KR102431719B1 - Electric brake system - Google Patents

Abstract

An electronic brake system is disclosed. The electronic brake system according to an embodiment of the present invention generates hydraulic pressure by operating a hydraulic piston by an electrical signal output in response to the displacement of the brake pedal, provided at one side of the hydraulic piston movably accommodated in the cylinder block. A first hydraulic pressure supplying device including a first pressure chamber connected to one or more wheel cylinders and a second pressure chamber connected to one or more wheel cylinders provided on the other side of the hydraulic piston, and a first hydraulic pressure controlling hydraulic pressure transmitted to the two wheel cylinders and a hydraulic control unit having a second hydraulic circuit for controlling hydraulic pressure transmitted to the circuit and the other two wheel cylinders, the hydraulic control unit comprising: a first hydraulic passage communicating with the first pressure chamber; The second and third hydraulic oil passages branched and connected to the first and second hydraulic circuits respectively, the fourth hydraulic oil passage communicating with the second pressure chamber and connected to the second hydraulic oil passage, the second hydraulic oil passage and the third hydraulic oil a fifth hydraulic flow path connecting the furnace, a sixth hydraulic flow path connecting the second hydraulic flow path and the fifth hydraulic flow path, and first and second control valves provided in the second hydraulic flow path to control the flow of the braking fluid; A point where the third control valve provided in the third hydraulic flow path to control the flow of the braking fluid, the fourth control valve provided in the fourth hydraulic flow path to control the flow of the braking fluid, and the sixth hydraulic flow path are connected on the fifth hydraulic flow path a fifth control valve provided between a point where the and the second hydraulic flow passage is connected; It may be provided including a seventh control valve provided in the hydraulic flow path.

Description

Electronic brake system

The present invention relates to an electronic brake system, and more particularly, to an electronic brake system that generates a braking force using an electrical signal corresponding to a displacement of a brake pedal.

A brake system for braking is essential to a vehicle. Recently, various types of systems for obtaining a stronger and more stable braking force have been proposed.

An example of the brake system is an anti-lock brake system (ABS) that prevents wheel slipping during braking, and a brake traction control system (BTCS: Brake) that prevents slipping of the driving wheels when the vehicle starts or accelerates rapidly. Traction Control System), and Electronic Stability Control System (ESC), which controls the brake fluid pressure by combining an anti-lock brake system and traction control to maintain a stable driving state of the vehicle.

The conventional brake system supplies hydraulic pressure required for braking to the wheel cylinders using a mechanically connected booster when the driver presses the brake pedal, but recently, when the driver presses the brake pedal, the driver's An electronic brake system including a hydraulic pressure supply device for supplying hydraulic pressure required for braking to wheel cylinders by receiving a braking intention as an electrical signal is widely used.

Meanwhile, as the market demand for eco-friendly vehicles increases, the popularity of hybrid-driven vehicles is increasing. In general, a hybrid vehicle refers to a vehicle that recovers kinetic energy as electrical energy while the vehicle is braking, stores it in a battery, and then uses it as an auxiliary to drive the vehicle. Such a hybrid vehicle has the advantage of improving fuel efficiency. It is popular with consumers.

A hybrid vehicle recovers energy by a generator or the like during a braking operation of the vehicle in order to increase the energy recovery rate. This braking operation is called regenerative braking. However, during regenerative braking, it affects the distribution of the braking force applied to a plurality of wheels of the vehicle, resulting in oversteering, understeering, or slipping of the vehicle, thereby hindering the driving stability of the vehicle. have.

EP 2 520 473 A1 (Honda Motor Co., Ltd.) 2012. 11. 7.

An embodiment of the present invention is to provide an electronic brake system capable of stably distributing and providing a braking pressure to each wheel even during regenerative braking of a vehicle.

An embodiment of the present invention is to provide an electronic brake system that can effectively implement braking in various operating situations.

An embodiment of the present invention is to provide an electronic brake system capable of promoting driving stability of a vehicle.

An embodiment of the present invention is to provide an electronic brake system capable of stably generating a high-pressure braking pressure.

An embodiment of the present invention is to provide an electronic brake system with improved performance and operational reliability.

An embodiment of the present invention aims to provide an electronic brake system with improved durability of a product by reducing a load applied to a component element.

An embodiment of the present invention is to provide an electronic brake system capable of reducing the size and number of parts of a product.

According to one aspect of the present invention, hydraulic piston is operated by an electric signal output in response to the displacement of the brake pedal to generate hydraulic pressure, and one or more wheels are provided at one side of the hydraulic piston movably accommodated in the cylinder block. A hydraulic pressure supply device including a first pressure chamber connected to the cylinder and a second pressure chamber connected to one or more wheel cylinders provided on the other side of the hydraulic piston, and a first hydraulic circuit for controlling the hydraulic pressure transmitted to the two wheel cylinders; and a hydraulic control unit having a second hydraulic circuit for controlling hydraulic pressure transmitted to the other two wheel cylinders, wherein the hydraulic control unit includes a first hydraulic oil passage communicating with the first pressure chamber, and the first hydraulic oil passage 2nd and 3rd hydraulic oil passages branched from and connected to the first and second hydraulic circuits, respectively; A fifth hydraulic oil passage connecting the third hydraulic oil passage, a sixth hydraulic oil passage connecting the second hydraulic oil passage and the fifth hydraulic oil passage, and a first hydraulic oil passage provided in the second hydraulic oil passage to control the flow of the braking fluid and a second control valve, a third control valve provided in the third hydraulic flow path to control the flow of the braking fluid, a fourth control valve provided in the fourth hydraulic flow path to control the flow of the braking fluid, and the fifth a fifth control valve provided between a point where the sixth hydraulic flow path is connected and a point where the second hydraulic flow path is connected on the hydraulic flow path; It may include a sixth control valve provided between the points connected to, and a seventh control valve provided in the sixth hydraulic flow path.

The second control valve may be provided at a rear end of a point where the fourth hydraulic flow path is connected on the second hydraulic flow path.

The second control valve may be provided at a front end of a point where the fourth hydraulic flow path is connected on the second hydraulic flow path.

The second, fourth, and seventh control valves are provided as solenoid valves for controlling the flow of the braking fluid in both directions, and the first control valve is provided with a brake in a direction from the first pressure chamber to the first hydraulic circuit. is provided as a check valve allowing only the flow of fluid, and the third control valve is provided as a check valve allowing only the flow of the braking fluid in a direction from the first pressure chamber to the second hydraulic circuit, and the fifth control The valve is provided as a check valve allowing only a flow of a braking fluid in a direction from the second hydraulic flow path to a point where the sixth hydraulic flow path is connected, and the sixth control valve is configured to allow the flow of the braking fluid from the third hydraulic flow path to the sixth hydraulic flow path. It may be provided as a check valve that allows only the flow of the braking fluid in the direction to the point where is connected.

The hydraulic control unit further includes a seventh hydraulic oil passage branched from a front end of the fourth control valve on the fourth hydraulic oil passage and connected to the third hydraulic line, and an eighth control valve provided in the seventh hydraulic oil passage. can do.

The eighth control valve may be provided as a check valve allowing only the flow of the braking fluid in a direction from the second pressure chamber to the second hydraulic circuit.

The electronic control unit may further include an electronic control unit for controlling the valves based on the generator and hydraulic pressure information provided in the two wheel cylinders of the first hydraulic circuit and the displacement information of the brake pedal.

and a pedal displacement sensor sensing a displacement of the brake pedal, wherein the electronic control unit controls to open the second and seventh control valves when the pedal displacement sensor detects the displacement of the brake pedal, It can be controlled to close the second control valve during regenerative braking by the generator.

and a flow path pressure sensor sensing the hydraulic pressure of at least one of the first hydraulic circuit and the second hydraulic circuit, wherein the electronic control unit is configured to detect when the hydraulic pressure detected by the flow path pressure sensor is higher than a preset pressure level. At least a portion of the braking fluid discharged from the first pressure chamber may be controlled to be supplied to the second pressure chamber by opening the fourth control valve.

A master cylinder having a reservoir in which braking fluid is stored, first and second master chambers, and first and second pistons provided in each master chamber, the master cylinder discharging the braking fluid by a pedal effort of the brake pedal, a simulation chamber; , a simulation device provided with a reaction force piston provided in the simulation chamber, the simulation apparatus receiving the braking fluid discharged from the first master chamber and providing a reaction force to the pedal force of the brake pedal, the simulation chamber and the first master chamber; A reservoir flow path communicating with the reservoir, a simulator check valve provided in the reservoir flow path, and allowing only a flow of braking fluid from the reservoir to the first master chamber and the simulation chamber, and the simulator check valve on the reservoir flow path A simulator valve provided in the bypass flow path connected in parallel to control the flow of the braking fluid, but may further include a simulator valve configured to control the flow of the braking fluid in both directions.

A first backup passage connecting the first master chamber and the first hydraulic circuit, a second backup passage connecting the second master chamber and the second hydraulic circuit, and a first selectively opening and closing the first backup passage It further includes a cut valve and a second cut valve selectively opening and closing the second backup flow path, wherein the first and second hydraulic circuits are provided on the upstream side of each wheel cylinder and include a plurality of inlet valves for selectively opening and closing the flow path. Including, at least one of the first backup flow path and the second backup flow path may connect the first or second master chamber and a downstream side of any one of the plurality of inlet valves.

A first dump flow path connecting the first pressure chamber and the reservoir, a second dump flow path connecting the second pressure chamber and the reservoir, and provided in the first dump flow path to control the flow of a braking fluid from the reservoir A first dump valve provided as a check valve for allowing only the flow of the braking fluid in the direction toward the first pressure chamber, a first dump valve provided in the second dump flow path to control the flow of the braking fluid, from the reservoir to the second pressure chamber A second dump valve provided as a check valve that allows only the flow of the braking fluid in a direction and a bypass flow path connected in parallel to the second dump valve on the second dump flow path to control the flow of the braking fluid, A third dump valve provided as a solenoid valve for controlling the flow of the braking fluid in both directions between the reservoir and the second pressure chamber may be further included.

The first hydraulic circuit includes first and second inlet valves respectively controlling the hydraulic pressure supplied to the two wheel cylinders, and first and second outlet valves controlling the hydraulic pressure discharged from the two wheel cylinders to the reservoir, respectively. The second hydraulic circuit includes third and fourth inlet valves respectively controlling the hydraulic pressure supplied to the other two wheel cylinders, and third and fourth inlet valves respectively controlling the hydraulic pressure discharged from the other two wheel cylinders to the reservoir. It may include a fourth outlet valve.

The electronic brake system according to an embodiment of the present invention has the effect of stably distributing the braking pressure transmitted to each wheel during regenerative braking of the vehicle.

The electronic brake system according to an embodiment of the present invention has the effect of improving the driving stability of the vehicle.

The electronic brake system according to an embodiment of the present invention has the effect of stably and effectively implementing braking in various operating situations of a vehicle.

The electronic brake system according to an embodiment of the present invention has an effect of stably generating a high-pressure braking pressure.

The electronic brake system according to an embodiment of the present invention has the effect of improving the performance and operational reliability of the product.

The electronic brake system according to an embodiment of the present invention has an effect of stably providing a braking pressure even when a component element is broken or a braking fluid leaks.

The electronic brake system according to an embodiment of the present invention has a simple structure and reduces the number of parts, thereby reducing the size and weight of the product.

The electronic brake system according to an embodiment of the present invention has the effect of improving the durability of the product by reducing the load applied to the component elements.

1 is a hydraulic circuit diagram showing an electronic brake system according to a first embodiment of the present invention.
2 is an enlarged view illustrating a master cylinder, a reservoir, and a reservoir flow path of the electronic brake system according to an embodiment of the present invention.
3 is an enlarged view showing a hydraulic pressure providing unit of the electronic brake system according to an embodiment of the present invention.
4 is a diagram schematically illustrating characteristics of hydraulic pressure and regenerative braking pressure of a wheel cylinder during regenerative braking using an electronic brake system according to an embodiment of the present invention.
5 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the first embodiment of the present invention provides braking pressure in a low pressure mode while moving forward.
6 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the first embodiment of the present invention implements rear wheel regenerative braking while providing braking pressure.
7 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the first embodiment of the present invention provides a braking pressure in a high-pressure mode while moving forward.
8 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the first embodiment of the present invention releases the braking pressure in the high-pressure mode while moving backward.
9 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the first embodiment of the present invention releases the braking pressure in the low pressure mode while moving backward.
10 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the first embodiment of the present invention releases the braking pressure while moving forward.
11 is a hydraulic circuit diagram illustrating an abnormally operating state of the electronic brake system according to the first embodiment of the present invention.
12 is a hydraulic circuit diagram illustrating a state in which the electronic brake system according to the first embodiment of the present invention checks whether air is present in the leak or the master cylinder of the simulation device.
13 is a hydraulic circuit diagram illustrating an electronic brake system according to a second embodiment of the present invention.
14 is a hydraulic circuit diagram illustrating an electronic brake system according to a third embodiment of the present invention.
15 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston of the electronic brake system according to the third embodiment of the present invention implements rear wheel regenerative braking while providing braking pressure.
16 is a hydraulic circuit diagram illustrating an electronic brake system according to a fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the embodiments presented herein and may be embodied in other forms. The drawings may omit the illustration of parts irrelevant to the description in order to clarify the present invention, and may slightly exaggerate the size of the components to help understanding.

1 is a hydraulic circuit diagram showing an electromagnetic brake system 1 according to a first embodiment of the present invention.

Referring to FIG. 1 , in the electronic brake system 1 according to the first embodiment of the present invention, the master cylinder 20 pressurizes and discharges braking fluid such as brake oil accommodated inside by the pedaling force of the brake pedal 10 . And, a reservoir 30 that communicates with the master cylinder 20 and stores a braking fluid therein, and a wheel cylinder 40 that brakes each wheel RR, RL, FR, FL by transmitting the hydraulic pressure of the braking fluid ), the simulation device 50 that provides the driver with a reaction force according to the pedal effort of the brake pedal 10, and the pedal displacement sensor 11 that detects the displacement of the brake pedal 10. The hydraulic pressure supply device 100 for generating hydraulic pressure of the braking fluid through mechanical operation, the hydraulic control unit 200 for controlling the hydraulic pressure transferred to the wheel cylinder 40, and hydraulic pressure information and pedal displacement information. Based on the hydraulic pressure supply device 100 and may include an electronic control unit (ECU, not shown) for controlling various valves.

The master cylinder 20 is configured to include at least one chamber to pressurize and discharge the inner braking fluid. 2 is an enlarged view illustrating a master cylinder, a reservoir, and a reservoir flow path of an electronic brake system according to an embodiment of the present invention. Referring to FIG. 2 , the master cylinder 20 includes a first master chamber 20a and a second A master chamber 20b and a first piston 21a and a second piston 21b provided in each of the master chambers 20a and 20b may be provided.

A first piston 21a connected to the input rod 12 is provided in the first master chamber 20a, and a second piston 22a is provided in the second master chamber 20b. In addition, braking fluid may be introduced and discharged into the first master chamber 20a by the first hydraulic port 24a, and the braking fluid may be introduced and discharged into the second master chamber 20b by the second hydraulic port 24b. can be ejected. For example, the first hydraulic port 24a may be connected to a first backup passage 251 to be described later, and the second hydraulic port 24b may be connected to a second backup passage 252 to be described later. Meanwhile, a third hydraulic port 24c connected to a first reservoir flow path 231 to be described later may be provided in the first master chamber 20a.

On the other hand, the master cylinder 20 according to an embodiment of the present invention can ensure safety in case of failure of the component element by independently providing two master chambers (20a, 20b). For example, one master chamber 20a of the two master chambers 20a and 20b is located on two wheels of the right front wheel (FR), left front wheel (FL), left rear wheel (RL), and right rear wheel (RR) of the vehicle. connected, and the other master chamber 20b may be connected to the other two wheels. Accordingly, even if one of the master chambers fails, it may be possible to brake the vehicle.

For example, one of the two master chambers may be connected to the two front wheels FR and FL, and the other master chamber may be connected to the two rear wheels RR and RL. In addition, one of the two master chambers is connected to the left front wheel (FL) and the left rear wheel (RL), and the other master chamber is connected to the right rear wheel (RR) and the right front wheel (FR). can That is, the position of the wheel connected to the master chamber of the master cylinder 20 is not limited to any one structure and may be configured in various ways.

A first spring 21b is provided between the first piston 21a and the second piston 22a of the master cylinder 20, and a second spring is provided between the second piston 22a and the end of the master cylinder 20. (22b) may be provided. That is, the first piston 21b may be accommodated in the first master chamber 20a, and the second piston 22b may be accommodated in the second master chamber 20b.

As for the first spring 21b and the second spring 22b, the first piston 21a and the second piston 22a move as the driver operates the brake pedal 10 to change the displacement, and at this time, the first The spring 21b and the second spring 22b are compressed. When the pedaling force of the brake pedal 10 is released, the first and second pistons 21a and 22a may return to their original positions while the first spring 21b and the second spring 22b expand by the elastic force.

Meanwhile, the brake pedal 10 and the first piston 21a of the master cylinder 20 may be connected to each other by the input rod 12 . The input rod 12 may be directly connected to the first piston 21a or may be provided in close contact without a gap, and accordingly, when the driver presses the brake pedal 10, the master cylinder directly without a pedal invalid stroke section ( 20) can be pressurized.

The first master chamber 20a is connected to the reservoir 30 together with the simulation chamber 51 of the simulation device 50 to be described later through the first reservoir flow path 61 , and the second master chamber 20b is connected to the second It may be connected to the reservoir 30 through the reservoir flow path 62 . The first reservoir flow path 61 may be provided to be connected to communicate with the rear end of the simulation chamber 51 of the simulation device 50 and the first master chamber 20a and the reservoir 30, and the first reservoir flow path ( 61 , a bypass flow path 63 , a simulator valve 54 , and a check valve 55 to be described later may be provided. A detailed description thereof will be provided later.

The master cylinder 20 includes two sealing members 25a and 25b disposed before and after the first reservoir flow path 61 connected to the first master chamber 20a and before and after the second reservoir flow path 62 . It may include two sealing members (25c, 25d). The sealing members 25a, 25b, 25c, and 25d may be provided in a ring-shaped structure protruding from the inner wall of the master cylinder 20 or the outer peripheral surface of the pistons 21a and 22a.

The simulation device 50 may be connected to a first backup flow path 251 to be described later and receive hydraulic pressure discharged from the first master chamber 20a, and may provide a reaction force to the pedal effort of the brake pedal 10 to the driver. . The simulation device 50 provides a reaction force in response to the pedal force applied by the driver to the brake pedal 10 , thereby providing the driver with a sense of pedal to facilitate detailed operation of the brake pedal 10 , and accordingly, the braking force of the vehicle is also can be fine-tuned.

1 and 2 , the simulation device 50 includes a simulation chamber 51 provided to receive the braking fluid discharged from the first hydraulic port 24a of the master cylinder 20 , and the simulation chamber 51 . A pedal simulator including a reaction force piston 52 provided and a reaction force spring 53 elastically supporting it, and a simulator valve 54 provided at the rear end of the simulation chamber 51 on the first reservoir flow path 61 . do.

The reaction force piston 52 and the reaction force spring 53 are formed in the simulation chamber 51 by a braking fluid flowing from the first master chamber 20a into the simulation chamber 51 through a first backup flow path 251 to be described later. It is provided to have a displacement in a certain range, and the simulator valve 54 is connected in parallel to the check valve 55 on the first reservoir flow path 61 connecting the rear end of the simulation chamber 51 and the reservoir 30 . can be Accordingly, even when the reaction force piston 52 returns to its original position, the braking fluid is introduced from the reservoir 30 so that the inside of the simulation chamber 51 can always be filled with the braking fluid.

On the other hand, the reaction spring 53 shown in the drawing is only an example that can provide an elastic force to the reaction force piston 52, and may be formed of various structures capable of storing the elastic force. For example, it may be made of a material such as rubber, or may be formed of various members capable of storing elastic force by having a coil or plate shape.

The check valve 55 allows the flow of the braking fluid flowing from the reservoir 30 to the first master chamber 20a and the simulation chamber 51 , but from the first master chamber 20a and the simulation chamber 51 to the reservoir A check valve 55 that blocks the flow of the braking fluid flowing into the 30 may be provided. In other words, the check valve 55 may be provided to allow only the flow of the braking fluid from the reservoir 30 to the first master chamber 20a and the simulation chamber 51 .

A bypass flow path 63 connected in parallel to the check valve 55 may be provided in the first reservoir flow path 61 , and a simulator valve controlling the flow of braking fluid in both directions is provided in the bypass flow path 63 . (54) may be provided. Specifically, the bypass flow path 63 may be provided by bypassing the front and rear sides of the check valve 55 on the first reservoir flow path 61 and connected, and the simulator valve 54 is normally closed and described later. It may be provided as a normally closed type solenoid valve that operates to open the valve when receiving an electrical signal from the electronic control unit.

The simulator valve 54 is opened when the driver applies a pedal force to the brake pedal 10 , so that the braking fluid accommodated on the rear side of the reaction force piston 52 (the right side of the reaction force piston in reference to the drawing) side of the simulation chamber 51 is released. so that it can be transmitted to the reservoir 30 through the first reservoir flow path 61, whereby the braking fluid in the first master chamber 20a is in front of the reaction force piston 52 of the simulation chamber 51 (reaction force based on the drawing) the left side of the piston) to compress the reaction force spring 53 to give a pedal feel to the driver.

The operation of the simulation device 50 will be described. When the driver operates the brake pedal 10 to apply a pedaling force, the simulator valve 54 is opened, and the first piston 21a moves to move the first master chamber 20a. The braking fluid in the inside is supplied to the front of the reaction force piston 52 in the simulation chamber 51 . Accordingly, the reaction force piston 52 compresses the reaction force spring 53 to provide a pedal feel to the driver. At this time, the braking fluid filled behind the reaction force piston 52 in the simulation chamber 51 moves along the first reservoir flow path 61 opened by opening the simulator valve 54 to be delivered to the reservoir 30 . have. Thereafter, when the driver releases the pedaling force of the brake pedal 10 , the reaction force spring 53 expands by the elastic force, the reaction force piston 52 returns to its original position, and the reaction force piston 52 is filled in front of the simulation chamber 51 . The lost braking fluid is discharged to the first master chamber 20a or the first backup flow path 251 , and the rear of the reaction force piston 52 in the simulation chamber 51 is from the reservoir 30 through the first reservoir flow path 61 . The braking fluid may be supplied and the inside of the simulation chamber 51 may be filled with the braking fluid again.

As such, since the inside of the simulation chamber 51 is always filled with the braking fluid, the friction of the reaction force piston 52 is minimized when the simulation device 50 is operated, so that the durability of the simulation device 50 is improved as well as from the outside. The inflow of foreign substances may be blocked.

On the other hand, several reservoirs 30 are shown in the drawing, and each of the reservoirs 30 uses the same reference numerals. These reservoirs may be provided with the same part or may be provided with different parts. As an example, the reservoir 30 connected to the simulation device 50 is the same as the reservoir 30 connected to the master cylinder 20 , or independently of the reservoir 30 connected to the master cylinder 20 . It may be a storage that can be stored.

The hydraulic pressure supply device 100 is provided to generate hydraulic pressure of the braking fluid through mechanical operation by receiving the driver's braking intention as an electrical signal from the pedal displacement sensor 11 that detects the displacement of the brake pedal 10 .

The hydraulic pressure supply device 100 includes a hydraulic pressure supply unit 110 that provides the braking fluid pressure transmitted to the wheel cylinder 40, and a motor 120 that generates a rotational force by an electrical signal from the pedal displacement sensor 11; It may include a power conversion unit 130 that converts the rotational motion of the motor 120 into a linear motion and transmits it to the hydraulic pressure providing unit 110 . The hydraulic pressure providing unit 110 may be operated by the pressure provided from the high-pressure accumulator instead of the driving force supplied from the motor 120 .

3 is an enlarged view showing a hydraulic pressure providing unit of the electronic brake system according to an embodiment of the present invention. Referring to FIG. 3 , the hydraulic pressure providing unit 110 is a cylinder block having a pressure chamber that receives and stores a braking fluid. (111), the hydraulic piston 114 accommodated in the cylinder block 111, the sealing members (115a, 115b) provided between the hydraulic piston 114 and the cylinder block 111 to seal the pressure chamber, and power conversion It includes a drive shaft 133 for transmitting the power output from the unit 130 to the hydraulic piston (114).

The pressure chamber includes a first pressure chamber 112 positioned in front of the hydraulic piston 114 (a forward direction, a left direction of the hydraulic piston in reference to the drawing), and a rear (reverse direction, according to the drawing) of the hydraulic piston 114 . to the right side of the hydraulic piston) may include a second pressure chamber 113 . That is, the first pressure chamber 112 is partitioned by the front end of the cylinder block 111 and the hydraulic piston 114 so that the volume varies according to the movement of the hydraulic piston 114 , and the second pressure chamber 113 . is partitioned by the rear end of the cylinder block 111 and the hydraulic piston 114 so that the volume varies according to the movement of the hydraulic piston 114 .

The first pressure chamber 112 is connected to a first hydraulic flow passage 211 to be described later through a first communication hole 111a formed in the cylinder block 111 , and the second pressure chamber 113 is connected to the cylinder block 111 . ) is connected to a fourth hydraulic flow path 214 to be described later through a second communication hole 111b formed in the .

The sealing member 115 includes a piston sealing member 115a provided between the hydraulic piston 114 and the cylinder block 111 to seal between the first pressure chamber 112 and the second pressure chamber 113 , and the drive shaft 133 . ) and a drive shaft sealing member 115b provided between the cylinder block 111 and sealing the openings of the second pressure chamber 113 and the cylinder block 111 . The hydraulic pressure or negative pressure of the first and second pressure chambers 112 and 13 generated by the forward or backward movement of the hydraulic piston 114 is sealed by the piston sealing member 115a so as not to leak into the second pressure chamber 113. The hydraulic pressure or negative pressure of the second pressure chamber 113 generated by the forward or backward movement of the hydraulic piston 114 may be transmitted to the first and fourth hydraulic passages 211 and 214 without the drive shaft sealing member 115b. may not leak to the outside of the cylinder block 111 by being sealed by the .

The first and second pressure chambers 112 and 113 are connected to the reservoir 30 by first and second dump passages 116 and 117, respectively, and are connected to the reservoir 30 by first and second dump passages 116 and 117, respectively. The braking fluid may be received and received from the reservoir 30 , or the braking fluid of the first or second pressure chambers 112 and 113 may be delivered to the reservoir 30 . To this end, the first dump passage 116 may be provided in communication with the first pressure chamber 112 through the third communication hole 111c formed in the cylinder block 111 to be connected to the reservoir 30, The second dump passage 117 may be provided in communication with the second pressure chamber 113 through the fourth communication hole 111d formed in the cylinder block 111 to be connected to the reservoir 30 .

The motor 120 is provided to generate a driving force by an electrical signal output from the electronic control unit (ECU). The motor 120 may be provided including a stator 121 and a rotor 122 , and may provide power for generating displacement of the hydraulic piston 114 by rotating in a forward or reverse direction through this. The rotation angular speed and rotation angle of the motor 120 may be precisely controlled by the motor control sensor MPS. Since the motor 120 is a well-known technology, a detailed description thereof will be omitted.

The power conversion unit 130 is provided to convert the rotational force of the motor 120 into linear motion. The power conversion unit 130 may be provided in a structure including, for example, a worm shaft 131 , a worm wheel 132 , and a drive shaft 133 .

The worm shaft 131 may be integrally formed with the rotation shaft of the motor 120 , and a worm may be formed on an outer circumferential surface to engage the worm wheel 132 to rotate the worm wheel 132 . The worm wheel 132 is connected to engage the drive shaft 133 to move the drive shaft 133 in a straight line, and the drive shaft 133 is connected to the hydraulic piston 114, through which the hydraulic piston 114 is a cylinder block. It can be moved by sliding within (111).

In describing the above operations again, when the displacement of the brake pedal 10 is detected by the pedal displacement sensor 11 , the detected signal is transmitted to the electronic control unit, and the electronic control unit drives the motor 120 to drive the worm shaft. (131) is rotated in one direction. The rotational force of the worm shaft 131 is transmitted to the drive shaft 133 via the worm wheel 132, and the hydraulic piston 114 connected to the drive shaft 133 advances in the cylinder block 111, the first pressure chamber 112. can create hydraulic pressure.

Conversely, when the pedal effort of the brake pedal 10 is released, the electronic control unit drives the motor 120 to rotate the worm shaft 131 in the opposite direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and the hydraulic piston 114 connected to the drive shaft 133 moves backward in the cylinder block 111 to generate a negative pressure in the first pressure chamber 112 .

The generation of hydraulic pressure and negative pressure in the second pressure chamber 113 may be implemented by operating in the opposite direction to the above. That is, when the displacement of the brake pedal 10 is detected by the pedal displacement sensor 11 , the sensed signal is transmitted to the electronic control unit, and the electronic control unit drives the motor 120 to reverse the worm shaft 131 . rotate in the direction The rotational force of the worm shaft 131 is transmitted to the drive shaft 133 via the worm wheel 132, and the hydraulic piston 114 connected to the drive shaft 133 moves backward in the cylinder block 111, while the second pressure chamber 113. can create hydraulic pressure.

Conversely, when the pedal effort of the brake pedal 10 is released, the electronic control unit drives the motor 120 in one direction to rotate the worm shaft 131 in one direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and the hydraulic piston 114 connected to the drive shaft 133 advances in the cylinder block 111 to generate a negative pressure in the second pressure chamber 113 .

As such, the hydraulic pressure supply device 100 generates hydraulic pressure or negative pressure in the first pressure chamber 112 and the second pressure chamber 113 according to the rotation direction of the worm shaft 131 by driving the motor 120 , respectively. Whether to implement braking by delivering hydraulic pressure or release braking by using negative pressure can be determined by controlling the valves. A detailed description thereof will be provided later.

Meanwhile, although not shown in the drawings, the power conversion unit 130 may be configured as a ball screw nut assembly. For example, it consists of a screw formed integrally with the rotation shaft of the motor 120 or connected to rotate with the rotation shaft of the motor 120, and a ball nut that is screwed with the screw in a state of limited rotation and moves linearly according to the rotation of the screw. Since the structure of such a ball screw nut assembly is a well-known technique, a detailed description thereof will be omitted. In addition, the power conversion unit 130 according to an embodiment of the present invention is not limited to any one structure as long as it can convert a rotational motion into a linear motion, and it should be understood equally even if it is made of a device of various structures and methods. will be.

The hydraulic control unit 200 may be provided to control the hydraulic pressure transmitted to the wheel cylinder 40, and the electronic control unit (ECU) controls the hydraulic pressure supply device 100 and various valves based on the hydraulic pressure information and the pedal displacement information. provided to control.

The hydraulic control unit 200 includes a first hydraulic circuit 201 that controls the flow of hydraulic pressure delivered to the two wheel cylinders 40 and a second hydraulic circuit that controls the flow of hydraulic pressure delivered to the other two wheel cylinders 40 . It may include a hydraulic circuit 202 , and includes a plurality of flow paths and valves to control hydraulic pressure transmitted from the master cylinder 20 and the hydraulic pressure supply device 100 to the wheel cylinder 40 .

Hereinafter, with reference to FIG. 1 again, the hydraulic control unit 200 will be described.

Referring to FIG. 1 , the first hydraulic flow path 211 is provided to connect the first pressure chamber 112 and the first and second hydraulic circuits 201 and 202 , and the first hydraulic flow path 211 is the first The second hydraulic oil passage 212 communicating with the hydraulic circuit 201 and the third hydraulic oil passage 213 communicating with the second hydraulic circuit 202 may be provided. Accordingly, the hydraulic pressure generated in the first pressure chamber 112 by the advancement of the hydraulic piston 114 is transferred to the first hydraulic circuit 201 and the second hydraulic circuit through the second hydraulic oil passage 212 and the third hydraulic oil passage 213 . 202 .

A first control valve 231 and a second control valve 232 for controlling the flow of the braking fluid may be sequentially provided in the second hydraulic flow path 212 . The first control valve 231 may be provided as a check valve that allows only the flow of the braking fluid in the direction from the first pressure chamber 112 to the first hydraulic circuit 201 and blocks the flow of the braking fluid in the opposite direction. . That is, the first control valve 231 allows the hydraulic pressure generated in the first pressure chamber 112 to be transmitted to the first hydraulic circuit 201, while the hydraulic pressure in the first hydraulic circuit 201 is transferred to the second hydraulic flow path ( It is possible to prevent leakage into the first pressure chamber 112 through the 212 .

The second control valve 231 may be provided at a rear end of a point where a fourth hydraulic flow path 214 to be described later is connected on the second hydraulic flow path 214 . The second control valve 232 may be provided as a two-way control valve that controls the flow of the braking fluid transmitted through the second hydraulic flow path 212 , and the second control valve 232 is normally opened. It may be provided as a solenoid valve of a normally open type that operates to close the valve when receiving an electrical signal from the electronic control unit.

The second control valve 232 is provided between the pressure chamber of the hydraulic pressure generating device and the wheel cylinder to implement regenerative braking and selectively connects the pressure chamber and the hydraulic circuit so that only a part of the hydraulic pressure of the braking fluid is transmitted to the wheel cylinder. and blocking. For example, as shown in FIG. 1 , the second control valve 232 includes the first pressure chamber 112 and the first wheel cylinder 40 of the rear wheels RL and RR in which the rear wheel regenerative braking is implemented. The first pressure chamber 112 and the first pressure chamber 112 are provided in the second hydraulic flow path 212 between the hydraulic circuits 201 so that only a part of the hydraulic pressure of the braking fluid is transmitted to the rear wheel cylinder 40 of the first hydraulic circuit 201 . 1 It is possible to selectively connect and block the hydraulic circuit 201 . A detailed description thereof will be provided later.

A third control valve 233 for controlling the flow of the braking fluid may be provided in the third hydraulic flow path 213 . The third control valve 233 may be provided as a check valve that allows only the flow of the braking fluid in the direction from the first pressure chamber 112 to the second hydraulic circuit 202 and blocks the flow of the braking fluid in the opposite direction. . That is, the third control valve 233 allows the hydraulic pressure generated in the first pressure chamber 112 to be transferred to the second hydraulic circuit 202, while the hydraulic pressure in the second hydraulic circuit 202 is transferred to the third hydraulic flow path ( It is possible to prevent leakage into the first pressure chamber 112 through the 213 .

The fourth hydraulic oil passage 214 may be provided to connect the second pressure chamber 113 and the first and second hydraulic circuits 201 and 202 , and the fifth hydraulic oil passage 215 has one end of the second hydraulic oil passage. The second hydraulic flow path ( It may be provided to connect the 212 and the third hydraulic flow path 213 . In addition, the sixth hydraulic oil passage 216 may be provided to connect the second hydraulic oil passage 212 and the fifth hydraulic oil passage 215 . To this end, both ends of the sixth hydraulic flow path 216 may be provided in communication with the front end of the second hydraulic flow path 212 and the first control valve 231 and the fifth hydraulic flow path 215 .

A fourth control valve 234 for controlling the flow of the braking fluid may be provided in the fourth hydraulic flow path 214 .

The fourth control valve 234 may be provided as a two-way control valve for controlling the flow of the braking fluid transmitted along the fourth hydraulic flow path 214 communicating with the second pressure chamber 113 . The fourth control valve 224 may be provided as a normally closed type solenoid valve that is normally closed and operates to open the valve when receiving an electrical signal from the electronic control unit.

Fifth and sixth control valves 235 and 236 for controlling the flow of the braking fluid may be provided in the fifth hydraulic flow path 215 .

The fifth control valve 235 may be provided on the fifth hydraulic flow path 215 between a point where the sixth hydraulic flow path 216 is connected and a point where the second hydraulic flow path 212 is connected, and the sixth control valve 216 ) may be provided between a point where the sixth hydraulic flow path 216 is connected and a point where the third hydraulic flow path 213 is connected on the fifth hydraulic flow path 215 . The fifth control valve 235 may be provided as a check valve allowing only the flow of the braking fluid in the direction from the second hydraulic flow path 212 to the point where the sixth hydraulic flow path 216 is connected, and the sixth control valve ( 236 may be provided as a check valve that allows only the flow of the braking fluid in a direction from the third hydraulic flow path 213 to the point where the sixth hydraulic flow path 216 is connected.

A seventh control valve 237 for controlling the flow of the braking fluid may be provided in the sixth hydraulic flow path 216 .

The seventh control valve 237 may be provided as a two-way control valve for controlling the flow of the braking fluid transmitted along the sixth hydraulic flow path 216 . The seventh control valve 227 may be provided as a normally closed type solenoid valve that is normally closed and operates to open when an electrical signal is received from the electronic control unit.

With this flow path and valve structure, the hydraulic pressure generated in the second pressure chamber 113 by the backward movement of the hydraulic piston 114 is supplied to the second hydraulic flow path 212 through the fourth hydraulic flow path 214, It can be supplied to the third hydraulic oil passage 212 through the 4 hydraulic oil passage 214 and the fifth hydraulic oil passage 215, so that the hydraulic pressure generated in the second pressure chamber 113 is applied to the first hydraulic circuit 201 and the second hydraulic circuit 201. 2 may be transmitted to the hydraulic circuit 202 .

The second and seventh control valves 232 and 237 may be operated to open when supplying the braking fluid from the wheel cylinder 40 to the first pressure chamber 112 to release the hydraulic pressure applied to the wheel cylinder 40 . . This is because the first and third control valves 231 and 233 are provided as check valves allowing only one-way braking fluid flow.

Hereinafter, the first hydraulic circuit 201 and the second hydraulic circuit 202 of the hydraulic control unit 200 will be described.

The first hydraulic circuit 201 controls the hydraulic pressure of the wheel cylinders 40 installed in the right rear wheel RR and the left rear wheel RL, and the second hydraulic circuit 202 is the right front wheel FR and the left front wheel ( It is possible to control the hydraulic pressure of the wheel cylinder 40 installed in the FL).

The first hydraulic circuit 201 is connected to the first hydraulic passage 211 and the second hydraulic passage 212 to receive hydraulic pressure from the hydraulic pressure supply device 100 , and the second hydraulic passage 212 is connected to the right rear wheel RR ) and the left rear wheel RL may be branched into two flow paths. Similarly, the second hydraulic circuit 202 is connected to the first hydraulic oil passage 211 and the third hydraulic oil passage 213 to receive hydraulic pressure from the hydraulic pressure supply device 100 , and the third hydraulic passage 213 is the right front wheel. It may be provided by branching into two flow paths connected to the FR and the left front wheel FL.

The first and second hydraulic circuits 201 and 202 may each include a plurality of inlet valves 221 (221a, 221b, 221c, 221d) to control the flow and hydraulic pressure of the braking fluid. As an example, the first hydraulic circuit 201 may be provided with two inlet valves 221a and 221b connected to the second hydraulic flow path 212 to respectively control the hydraulic pressure transmitted to the two wheel cylinders 40 , , the second hydraulic circuit 202 may be provided with two inlet valves 221c and 221d connected to the third hydraulic flow path 213 to respectively control the hydraulic pressure transmitted to the wheel cylinder 40 .

These inlet valves 221 are disposed on the upstream side of the wheel cylinder 40 and are normally open solenoid valves of a normal open type that operate to close the valve when receiving an electrical signal from the electronic control unit. can be provided with

The first and second hydraulic circuits 201 and 202 may include check valves 223a, 223b, 223c, and 223d that are connected in parallel to each of the inlet valves 221a, 221b, 221c, and 221d. . The check valves (223a, 223b, 223c, 223d) are provided on the first and second hydraulic circuits (201, 202) in the bypass flow path connecting the front and rear of each inlet valve (221a, 221b, 221c, 221d). It may be provided to allow only the flow of the braking fluid from the wheel cylinder 40 to the hydraulic pressure providing unit 110, and to block the flow of the braking fluid from the hydraulic pressure providing unit 110 to the wheel cylinder 40. . The check valves 223a, 223b, 223c, and 223d can quickly release the hydraulic pressure of the braking fluid applied to the wheel cylinder 40, and even when the inlet valves 221a, 221b, 221c, and 221d do not operate normally, the wheel The hydraulic pressure of the braking fluid applied to the cylinder 40 may be introduced into the hydraulic pressure providing unit 110 .

The first and second hydraulic circuits 201 and 202 further include a plurality of outlet valves 222: 222a, 222b, 222c, 222d connected to the reservoir 30 to improve performance when braking of the wheel cylinder 40 is released. can be provided The outlet valves 222 are respectively connected to the wheel cylinders 40 to control the flow of the braking fluid exiting from the wheel cylinders 40 of the respective wheels RR, RL, FR, and FL. That is, the outlet valve 222 senses the braking pressure of each of the wheels RR, RL, FR, and FL and selectively opens when pressure-reducing braking is required to control the pressure reduction of the wheel cylinder 40 .

The outlet valve 222 may be provided as a normally closed type solenoid valve that is normally closed and operates to open when an electrical signal is received from the electronic control unit.

Meanwhile, first and second dump valves 241 and 242 for controlling the flow of the braking fluid may be provided in the first and second dump passages 116 and 117 , respectively. Referring back to FIG. 1 , the first and second dump valves 241 and 242 allow only the flow of the braking fluid from the reservoir 30 to the first and second pressure chambers 112 and 113 , and The brake fluid flow may be provided as a check valve that shuts off. That is, the first dump valve 241 allows the braking fluid to flow from the reservoir 30 to the first pressure chamber 112 , but the braking fluid flowing from the first pressure chamber 112 to the reservoir 30 is The second dump valve 242 allows the braking fluid to flow from the reservoir 30 to the second pressure chamber 113 , but the braking fluid flows from the second pressure chamber 113 to the reservoir 30 . things can be blocked.

In addition, a bypass flow path connected in parallel to the second dump valve 242 may be provided in the second dump flow path 117 . Specifically, the bypass flow path may be provided by bypassing the front and rear sides of the second dump valve 242 on the second dump flow path 117 and connected, and the bypass flow path includes the second pressure chamber 113 and the reservoir ( 30) A third dump valve 243 for controlling the flow of the braking fluid may be provided.

The third dump valve 243 may be provided as a two-way control valve for controlling the flow of the braking fluid between the second pressure chamber 113 and the reservoir 30 . The third dump valve 243 may be provided as a normally open type solenoid valve that is normally open and operates to close the valve when receiving an electrical signal from the electronic control unit.

The hydraulic pressure providing unit 110 of the electromagnetic brake system 1 according to an embodiment of the present invention may be operated in a double acting type.

Specifically, the hydraulic pressure generated in the first pressure chamber 112 while the hydraulic piston 114 moves forward is transmitted to the first hydraulic circuit 201 through the first hydraulic oil passage 211 and the second hydraulic oil passage 212 . Braking of the wheel cylinders 40 installed on the right rear wheel RR and the left rear wheel RL can be implemented, and the second hydraulic circuit 202 through the first hydraulic oil passage 211 and the third hydraulic oil passage 213 . It is possible to implement braking of the wheel cylinder 40 which is transmitted to the right front wheel FR and the left front wheel FL.

Similarly, the hydraulic pressure generated in the second pressure chamber 113 while the hydraulic piston 114 moves backward is transmitted to the first hydraulic circuit 201 through the fourth hydraulic oil passage 214 and the second hydraulic oil passage 212 to the right side. Braking of the wheel cylinder 40 installed on the rear wheel RR and the left rear wheel RL can be implemented, and the second hydraulic circuit 202 is similarly passed through the fourth hydraulic flow path 214 and the third hydraulic flow path 213 . ) to implement braking of the wheel cylinder 40 installed on the right front wheel FR and the left front wheel FL.

In addition, the negative pressure generated in the first pressure chamber 112 while the hydraulic piston 114 moves backward sucks the braking fluid of the wheel cylinders 40 installed in the right rear wheel RR and the left rear wheel RL, so that the first hydraulic pressure is applied. The braking fluid may be returned from the circuit 201 to the first pressure chamber 112 through the second hydraulic path 212 , the fifth hydraulic path 215 , and the sixth hydraulic path 216 , and the right front wheel FR ( The braking fluid may be returned to the first pressure chamber 112 through 216 .

In addition, when the electronic brake system 1 according to an embodiment of the present invention cannot operate normally due to a malfunction of the device, the braking fluid discharged from the master cylinder 20 is directly supplied to the wheel cylinder 40 to perform braking. It may include first and second backup flow paths 251 and 252 that can be implemented. A mode in which the hydraulic pressure of the master cylinder 20 is directly transmitted to the wheel cylinder 40 is referred to as a fallback mode.

The first backup passage 251 is provided to connect the first hydraulic port 24a of the master cylinder 20 and the first hydraulic circuit 201 , and the second backup passage 252 is the first of the master cylinder 20 . 2 may be provided to connect the hydraulic port (24b) and the second hydraulic circuit (202). Specifically, the first backup flow path 251 may be connected to join the rear end of the first or second inlet valves 221a and 221b on the first hydraulic circuit 201 , and the second backup flow path 252 is the second It may be connected to join the rear end of the third or fourth inlet valves 221c and 221d on the hydraulic circuit 202 .

A first cut valve 261 for controlling the flow of the braking fluid is provided in the first backup flow passage 251 , and a second cut valve 262 for controlling the flow of the braking fluid is provided in the second backup flow passage 252 . can be The first and second cut valves 261 and 262 may be provided as normal open type solenoid valves that are normally open and operate to close the valves when a closing signal is received from the electronic control unit. .

Accordingly, when the first and second cut valves 261 and 262 are closed, the hydraulic pressure provided from the hydraulic pressure supply device 100 is transferred to the wheel cylinder 40 through the first and second hydraulic circuits 201 and 202 . may be supplied, and when the first and second cut valves 261 and 262 are opened, the hydraulic pressure provided from the master cylinder 20 is transferred to the wheel cylinder 40 through the first and second backup passages 251 and 252. ) can be supplied.

The electronic brake system 1 according to the first embodiment of the present invention includes a backup passage pressure sensor PS1 for sensing the hydraulic pressure of a master cylinder 20, a first hydraulic circuit 201 and a second hydraulic circuit 202. It may include a flow path pressure sensor (PS21, PS22) for sensing at least any one of the hydraulic pressure. The backup flow path pressure sensor PS1 is, for example, provided at the front end of the first cut valve 262 on the first backup flow path 251 to sense hydraulic pressure generated from the master cylinder 20, and the flow path pressure sensor PS21, PS22) is provided at the front end of the inlet valve 221 of at least one of the first hydraulic circuit 201 and the second hydraulic circuit 202, and hydraulic pressure applied to the first hydraulic circuit 201 and the second hydraulic circuit 202 can detect In the drawings, the flow path pressure sensors PS21 and PS22 are illustrated as being provided in the first hydraulic circuit 201 and the second hydraulic circuit 202, respectively, but the structure is not limited thereto, and the hydraulic circuits 201 and 202 are not limited thereto. If it can sense the hydraulic pressure applied to it, it includes a case where one or various numbers are provided.

Meanwhile, in recent years, as the market demand for eco-friendly vehicles increases, hybrid vehicles with improved fuel efficiency are gaining popularity. A hybrid vehicle recovers kinetic energy as electric energy while the vehicle is braking, stores it in a battery, and uses the motor as an auxiliary driving source of the vehicle. During operation, energy is recovered by a generator (not shown) or the like. This braking operation is called regenerative braking. However, since regenerative braking pressure by a generator is added to the braking fluid pressure by hydraulic pressure applied to the four wheels of the vehicle during regenerative braking, the braking fluid pressure by the hydraulic pressure supply device so that the braking force applied to the four wheels is constant for safe braking. Cooperative control between and regenerative braking pressure should be closely performed.

4 is a diagram schematically illustrating characteristics of hydraulic pressure and regenerative braking pressure of a wheel cylinder during regenerative braking using an electronic brake system according to an embodiment of the present invention.

Referring to FIG. 4 , as shown as an example in FIG. 1 , when an energy recovery device such as a generator is installed on the rear wheels RL and RR of the first hydraulic circuit 201 , corresponding to the braking level the driver wants to implement. The brake fluid pressure is generated by the hydraulic pressure supply device, and the total braking force of the front wheel to which only the brake fluid pressure by hydraulic pressure is transmitted increases and maintains the same as the braking fluid pressure desired by the driver. However, in the case of a rear wheel that implements regenerative braking, the total braking force of the rear wheel to which the braking fluid pressure from the hydraulic pressure supply device and the regenerative braking pressure from the generator are added must be the same as the total braking force of the front wheels or the braking fluid pressure desired by the driver. Therefore, as the vehicle starts to implement regenerative braking, the second control valve 232 of the hydraulic control unit 200 is closed, so that the brake fluid pressure by the hydraulic pressure supply device applied to the rear wheels is kept constant, and at the same time , the regenerative braking force pressure by an energy recovery device such as a generator may increase, so that the total braking force of the rear wheels may be equal to the total braking force of the front wheels or the braking fluid pressure desired by the driver. A detailed description thereof will be described later with reference to FIG. 6 .

Hereinafter, the operation of the electronic brake system 1 according to an embodiment of the present invention will be described.

The electronic brake system 1 according to an embodiment of the present invention may use the hydraulic pressure supply device 100 by dividing it into a low pressure mode and a high pressure mode. The low-pressure mode and the high-pressure mode can be changed by changing the operation of the hydraulic control unit 200 . The hydraulic pressure supply device 100 can provide a high hydraulic pressure without increasing the output of the motor 120 by using the high-pressure mode, and further reduce the load applied to the motor 120 . Accordingly, a stable braking force may be secured while reducing the cost and weight of the brake system, and durability and operational reliability of the device may be improved.

When the hydraulic piston 114 moves forward by driving the motor 120 , hydraulic pressure is generated in the first pressure chamber 112 . As the hydraulic piston 114 advances from the initial position, that is, as the operating stroke of the hydraulic piston 114 increases, the supply amount of the braking fluid transferred from the first pressure chamber 112 to the wheel cylinder 40 increases, and the braking pressure decreases. rises However, since the hydraulic piston 114 has an effective stroke, there is a maximum pressure due to the advance of the hydraulic piston 114 .

At this time, the maximum pressure in the low pressure mode is smaller than the maximum pressure in the high pressure mode. However, in the high pressure mode, the pressure increase rate per stroke of the hydraulic piston 114 is smaller than in the low pressure mode. This is because not all of the braking fluid discharged from the first pressure chamber 112 is transferred to the wheel cylinder 40 , but some of it is transferred to the second pressure chamber 113 . This will be described later with reference to FIG. 7 .

Therefore, the low pressure mode with a large pressure increase rate per stroke can be used in the early stage of braking when braking response is important, and the high pressure mode with a large maximum pressure can be used in the late stage of braking when the maximum braking force is important.

5 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston 114 of the electronic brake system 1 according to the first embodiment of the present invention provides a braking pressure in a low pressure mode while moving forward, and FIG. 6 is the braking pressure of FIG. It is a hydraulic circuit diagram showing a state in which rear wheel regenerative braking is implemented in the provided state. 7 is a hydraulic circuit diagram showing a state in which the hydraulic piston 114 of the electromagnetic brake system 1 according to the first embodiment of the present invention provides a braking pressure in a high-pressure mode while moving forward.

Referring to FIG. 5 , when the driver steps on the brake pedal 10 at the initial stage of braking, the motor 120 operates to rotate in one direction, and the rotational force of the motor 120 is transmitted by the power transmission unit 130 to the hydraulic pressure providing unit It is transferred to 110 , and the hydraulic piston 114 of the hydraulic pressure providing unit 110 advances to generate hydraulic pressure in the first pressure chamber 112 . The hydraulic pressure discharged from the first pressure chamber 112 is transmitted to the wheel cylinders 40 provided in each of the four wheels through the first hydraulic circuit 201 and the second hydraulic circuit 202 to generate braking force.

Specifically, the hydraulic pressure provided from the first pressure chamber 112 is applied to the first hydraulic circuit 201 through the first hydraulic passage 211 and the second hydraulic passage 212 connected to the first communication hole 111a. It is directly transmitted to the wheel cylinder 40 provided. At this time, the first and second inlet valves 221a and 221b respectively installed in the two flow paths branching from the first hydraulic circuit 201 are provided in an open state, and the two flow paths branching from the first hydraulic circuit 201 . The first and second outlet valves 222a and 222b installed in the flow paths branching from the .

In addition, the hydraulic pressure provided from the first pressure chamber 112 is provided in the second hydraulic circuit 202 through the first hydraulic passage 211 and the third hydraulic passage 213 connected to the first communication hole 111a. It is transmitted directly to the wheel cylinder (40). At this time, the third and fourth inlet valves 221c and 221d respectively installed in the two flow paths branching from the second hydraulic circuit 202 are provided in an open state, and the two flow paths branching from the second hydraulic circuit 202 . The third and fourth outlet valves 222c and 222d installed in the flow paths branching from the . At this time, the second control valve 232 may maintain an open state, and the seventh control valve 237 may also be switched to an open state.

The fourth control valve 234 may be maintained in a closed state to block the fourth hydraulic flow path 214 . Through this, it is possible to prevent the hydraulic pressure generated in the first pressure chamber 112 from being transmitted to the second pressure chamber 113 through the fourth hydraulic flow passage 214 to improve the pressure increase rate per stroke of the hydraulic piston 114 . . Therefore, it is possible to achieve a quick braking response at the initial stage of braking.

When the hydraulic pressure of the braking fluid is generated by the hydraulic pressure supply device 100 , the first and second cut valves 261 and 262 provided in the first and second backup passages 251 and 252 are closed and in the master cylinder 20 . It is possible to prevent the discharged hydraulic pressure from being transmitted to the wheel cylinder 40 . The hydraulic pressure generated in the master cylinder 20 according to the pedal effort of the brake pedal 10 is transmitted to the simulation device 50 connected to the master cylinder 20 . At this time, the simulator valve 54 provided in the first reservoir flow path 61 is opened, and the braking fluid discharged from the first master chamber 20a of the master cylinder 20 is transmitted to the front of the reaction force piston 52 . As the reaction force piston 52 moves, the reaction force spring 53 is compressed, and the braking fluid accommodated in the simulation chamber 51 is stored in the reservoir ( 30) is transferred. By the elastic restoring force generated while the reaction force spring 53 is compressed, a reaction force corresponding to the pedal force may act, thereby providing an appropriate pedal feeling to the driver.

The flow path pressure sensors PS21 and PS22 that sense the hydraulic pressure of at least one of the first hydraulic circuit 201 and the second hydraulic circuit 202 sense the hydraulic pressure transmitted to the wheel cylinder 40, and supply hydraulic pressure based on this. By controlling the operation of the device 100 , the flow rate or hydraulic pressure of the braking fluid delivered to the wheel cylinder 40 may be controlled. Further, when regenerative braking of the rear wheel cylinder 40 of the first hydraulic circuit 201, the electronic control unit operates the closing operation of the second control valve 232 based on the pressure information sensed by the flow path pressure sensor P21. And it is possible to determine the operating time. In addition, when the hydraulic pressure transmitted to the wheel cylinder 40 is higher than the target pressure value according to the pedal effort of the brake pedal 10 , at least one of the first to fourth outlet valves 222 is opened to correspond to the target pressure value. The hydraulic pressure can be controlled to

Hereinafter, the operation of the rear wheel regenerative braking of the electronic brake system 1 according to an embodiment of the present invention will be described.

Referring to FIG. 6 , as described above, when the driver steps on the brake pedal 10 at the initial stage of braking for providing the pressure provided in the low pressure mode, the motor 120 operates to rotate in one direction, and the The rotational force is transmitted to the hydraulic pressure providing unit 110 by the power transmitting unit 130 , and the hydraulic piston 114 of the hydraulic pressure providing unit 110 advances to generate hydraulic pressure in the first pressure chamber 112 . The hydraulic pressure discharged from the first pressure chamber 112 is transmitted to the wheel cylinders 40 provided in each of the four wheels through the first hydraulic circuit 201 and the second hydraulic circuit 202 to generate braking force.

After that, when the electronic control unit determines that the regenerative braking is driven in the rear wheel of the vehicle, specifically, the wheel cylinder 40 of the first hydraulic circuit 201, the electronic control unit controls the driver's required braking pressure and the regenerative braking pressure. The size of the brake fluid pressure calculated according to the difference is calculated, and the first hydraulic circuit 201 can control to close the second control valve 232 after the hydraulic pressure is applied to the rear wheel cylinder 40 by the corresponding pressure level. have. Therefore, the hydraulic pressure of the rear wheel in which the regenerative braking occurs is lower than when the regenerative braking is not driven.

The electronic control unit uses a flow path pressure sensor PS21 that senses the hydraulic pressure of the first hydraulic circuit 201 , and the brake transmitted from the hydraulic pressure supply device 100 to the rear wheel cylinder 40 of the first hydraulic circuit 201 . The hydraulic pressure can be controlled stably. Specifically, the electronic control unit transmits the brake fluid pressure from the hydraulic pressure supply device 100 to the front wheel cylinder 40 of the second hydraulic circuit 202 to which only the hydraulic pressure is transmitted through the flow path pressure sensor PS22. Detected through and compared with the braking fluid pressure delivered to the rear wheel cylinder 40 of the first hydraulic circuit, the rear wheel to be blocked or reduced in the rear wheel cylinder 40 of the first hydraulic circuit 201 during regenerative braking. The brake fluid pressure can be controlled more precisely.

As such, as the electronic control unit controls the operation of the second control valve 232 during regenerative braking of the rear wheel, the braking fluid pressure applied to the rear wheel cylinder 40 of the first hydraulic circuit 201 is applied to the regenerative braking pressure. It can be adjusted stably according to the requirements of the vehicle, thereby uniformly distributing the braking pressure or braking force applied to the four wheels of the vehicle to ensure the vehicle's braking stability and to prevent oversteering or understeering to drive the vehicle. Stability can be improved.

The hydraulic pressure supply device 100 of the electronic brake system 1 according to the embodiment of the present invention is the high pressure mode shown in FIG. 7 in the low pressure mode shown in FIGS. 5 and 6 before the hydraulic piston 114 advances to the maximum. can be converted to

Referring to FIG. 7 , when the hydraulic pressure sensed by the flow path pressure sensors PS21 and PS22 is higher than a preset pressure level, the electronic control unit may switch from the low pressure mode to the high pressure mode. In the high pressure mode, the fourth control valve 234 may be switched to an open state to open the fourth hydraulic flow path 214 . Accordingly, some of the hydraulic pressure generated in the first pressure chamber 112 sequentially passes through the first hydraulic flow path 211 , the second hydraulic flow path 212 , and the fourth hydraulic flow path 214 to the second pressure chamber 113 . It can be utilized to further advance the hydraulic piston 114 by being transmitted and to reduce the load applied to the motor 120 .

In the high pressure mode, since a portion of the braking fluid discharged from the first pressure chamber 112 flows into the second pressure chamber 113 , the pressure increase rate per stroke decreases. However, since a portion of the hydraulic pressure generated in the first pressure chamber 112 is utilized to further advance the hydraulic piston 114 , the maximum pressure of the braking fluid may increase. This is because, as the drive shaft 133 passes through the second pressure chamber 113, the volume change rate per stroke of the hydraulic piston 114 is relatively smaller in the second pressure chamber 113 than in the first pressure chamber 112. .

In addition, as the hydraulic piston 114 moves forward, the hydraulic pressure of the first pressure chamber 112 increases, so that the hydraulic pressure of the first pressure chamber 112 increases the force to move the hydraulic piston 114 backward. Accordingly, the motor ( 120) is also increased. However, by opening the fourth hydraulic circuit 214 under the control of the fourth control valve 234 , a part of the braking fluid discharged from the first pressure chamber 112 is transferred to the second pressure chamber 113 , Hydraulic pressure is also formed in the second pressure chamber 113 to reduce the load applied to the motor 120 .

At this time, the third dump valve 243 may be switched to a closed state. As the third dump valve 243 is closed, the braking fluid in the first pressure chamber 112 can be quickly introduced into the second pressure chamber 113 in a negative pressure state, and hydraulic pressure can also be applied to the second pressure chamber 113 . have. However, if necessary, the third dump valve 243 may be maintained in an open state so that the braking fluid in the second pressure chamber 113 may be controlled to flow into the reservoir 30 .

Hereinafter, the operating state of releasing the braking pressure in the normal operating state of the electronic brake system 1 according to an embodiment of the present invention will be described.

8 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston 114 of the electronic brake system 1 according to an embodiment of the present invention releases the braking pressure in the high-pressure mode while moving backward. It is a hydraulic circuit diagram showing a state in which the hydraulic piston 114 of the electromagnetic brake system 1 releases the braking pressure in the low pressure mode while moving backward.

Referring to FIG. 8 , when the pedal force applied to the brake pedal 10 is released, the motor 120 generates a rotational force in the opposite direction during braking and transmits it to the power conversion unit 130 , and a worm of the power conversion unit 130 . The shaft 131 , the worm wheel 132 , and the drive shaft 133 rotate in the opposite direction during braking to reverse the hydraulic piston 114 to its original position. Thereby, the hydraulic pressure in the first pressure chamber 112 can be released, and negative pressure can be generated. At the same time, the braking fluid discharged from the wheel cylinder 40 is transmitted to the first pressure chamber 112 through the first and second hydraulic circuits 201 and 202 .

Specifically, the negative pressure generated in the first pressure chamber 112 is first applied through the second hydraulic oil passage 212 , the fifth hydraulic oil passage 215 , the sixth hydraulic oil passage 216 , and the first hydraulic oil passage 211 . The pressure of the wheel cylinder 40 provided in the hydraulic circuit 201 is released. At this time, the first and second inlet valves 221a and 221b respectively installed in the two flow paths branching from the first hydraulic circuit 201 are maintained in an open state, and the two flow paths branching from the second hydraulic circuit 201 . The first and second outlet valves 222a and 222b installed in the flow passages respectively branched from the . At this time, the second control valve 232 provided in the second hydraulic oil passage 212 and the seventh control valve 237 provided in the sixth hydraulic oil passage 216 are controlled in an open state.

In addition, the negative pressure generated in the first pressure chamber 112 is a third hydraulic oil passage 213 connected to the first communication hole 111a, a fifth hydraulic oil passage 215, a sixth hydraulic oil passage 216, the first The pressure of the wheel cylinder 40 provided in the second hydraulic circuit 202 is released through the hydraulic flow path 211 . At this time, the third and fourth inlet valves 221c and 221d respectively installed in the two flow paths branching from the second hydraulic circuit 202 are maintained in an open state, and the two flow paths branching from the second hydraulic circuit 202 are maintained. The third and fourth outlet valves 222c and 222d installed in the flow paths branching from the .

Meanwhile, the first control valve 234 is also switched to an open state to open the fourth hydraulic flow path 214 , so that the first pressure chamber 112 and the second pressure chamber 113 communicate with each other.

That is, in order for the negative pressure to be formed in the first pressure chamber 112 , the hydraulic piston 114 must move backward, but when the hydraulic pressure of the braking fluid exists in the second pressure chamber 113 , the reverse movement of the hydraulic piston 114 is resisted. This happens. Accordingly, by switching the fourth control valve 234 to an open state to communicate the first pressure chamber 112 and the second pressure chamber 113 , the braking fluid in the second pressure chamber 113 is transferred to the first pressure chamber 112 . ) can be supplied.

At this time, the third dump valve 243 may be switched to a closed state. As the third dump valve 243 is closed, the braking fluid in the second pressure chamber 113 may be discharged only through the fourth hydraulic flow path 214 . However, if necessary, the third dump valve 243 may be maintained in an open state so that the braking fluid in the second pressure chamber 113 may be controlled to flow into the reservoir 30 .

In addition, when the negative pressure transmitted to the first and second hydraulic circuits 201 and 202 is measured to be higher than the target pressure release value according to the release amount of the brake pedal 10 , among the first to fourth outlet valves 222 , At least one of the openings may be controlled to correspond to a target pressure value. In addition, the first and second cut valves 261 and 262 installed in the first and second backup passages 251 and 252 are closed so that the negative pressure formed in the master cylinder 20 is not transmitted to the hydraulic control unit 200 . can be controlled not to.

On the other hand, in the operating state of the high pressure mode shown in FIG. 8 , not only the braking fluid in the wheel cylinder 40 but also the second pressure chamber 113 due to the negative pressure in the first pressure chamber 112 generated while the hydraulic piston 114 moves backward. ) because the braking fluid in the first pressure chamber 112 is supplied to the pressure reduction rate of the wheel cylinder 40 is small. Therefore, it may be difficult to quickly release the braking pressure in the high pressure mode. For this reason, the braking pressure release operation in the high-pressure mode can be used only in a high-pressure situation of the braking pressure, and when the braking pressure is below a certain level, the braking pressure release operation of the low-pressure mode shown in FIG. can

Referring to FIG. 9 , when the braking pressure is released in the low pressure mode, the fourth control valve 234 is maintained or switched to the closed state to close the fourth hydraulic flow path 214 and the third dump valve 243 is The second pressure chamber 113 and the reservoir 30 may communicate with each other by being switched or maintained in an open state.

When the braking pressure is released in the low pressure mode, the negative pressure generated in the first pressure chamber 112 is used only to recover the braking fluid of the wheel cylinder 40, and compared with the case of releasing the braking pressure in the high pressure mode, the hydraulic piston 114 ) increases the rate of pressure reduction per stroke. At this time, the hydraulic pressure generated in the second pressure chamber 113 by the backward movement of the hydraulic piston 114 is transferred to the reservoir 30 as the third dump valve 243 is switched to an open state.

Unlike FIG. 9 , even when the hydraulic piston 114 moves forward, it is possible to release the braking pressure of the wheel cylinder 40 .

10 is a hydraulic circuit diagram showing a state in which the hydraulic piston 114 of the electronic brake system 1 according to the first embodiment of the present invention releases the braking pressure while moving forward.

Referring to FIG. 10 , when the pedal force applied to the brake pedal 10 is released, the motor 120 generates a rotational force in the opposite direction during braking and transmits it to the power conversion unit 130 , and a worm of the power conversion unit 130 . The shaft 131, the worm wheel 132, and the drive shaft 133 rotate in the opposite direction during braking to advance the hydraulic piston 114 to the original position to release the hydraulic pressure in the second pressure chamber 113, and to release the negative pressure. generate At the same time, the braking fluid discharged from the wheel cylinder 40 is transmitted to the second pressure chamber 113 through the first and second hydraulic circuits 201 and 202 .

Specifically, the negative pressure generated in the second pressure chamber 113 is applied to the first hydraulic circuit 201 through the fourth hydraulic passage 214 and the second hydraulic passage 212 connected to the second communication hole 111b. Release the pressure of the wheel cylinder 40 provided. At this time, the first and second inlet valves 221a and 221b respectively installed in the two flow paths branching from the first hydraulic circuit 201 are maintained in an open state, and the two flow paths branching from the first hydraulic circuit 201 . The first and second outlet valves 222a and 222b installed in the flow paths branching from the .

In addition, the negative pressure generated in the second pressure chamber 113 is a fourth hydraulic passage 214 , a second hydraulic passage 212 , a sixth hydraulic passage 216 , and a fifth connected to the second communication hole 111b. The pressure of the wheel cylinder 40 provided in the second hydraulic circuit 202 is released through the sixth control valve 236 side passage of the hydraulic oil passage 215 and the third hydraulic oil passage 213 . At this time, the third and fourth inlet valves 221c and 221d respectively installed in the two flow paths branching from the second hydraulic circuit 202 are maintained in an open state, and the two flow paths branching from the second hydraulic circuit 202 are maintained. The third and fourth outlet valves 222c and 222d installed in the flow passages respectively branched from the .

At this time, the fourth control valve 234 is switched to the open state to open the fourth hydraulic flow path 214 , and the seventh control valve 237 is also switched to the open state to open the sixth hydraulic flow path 216 . can be controlled.

In addition, the third dump valve 243 may be switched to a closed state, whereby the negative pressure formed in the second pressure chamber 113 may quickly recover the braking fluid of the wheel cylinder 40 .

In addition, when the negative pressure transmitted to the first and second hydraulic circuits 201 and 202 is measured to be higher than the target pressure release value according to the release amount of the brake pedal 10 , among the first to fourth outlet valves 222 , At least one of the openings may be controlled to correspond to a target pressure value. In addition, the first and second cut valves 261 and 262 installed in the first and second backup passages 251 and 252 are closed so that the negative pressure formed in the master cylinder 20 is not transmitted to the hydraulic control unit 200 . can be controlled not to.

Hereinafter, an operating state when the electronic brake system 1 according to the first embodiment of the present invention does not operate normally will be described.

11 is a hydraulic circuit diagram illustrating a state in which the electronic brake system 1 according to the first embodiment of the present invention operates abnormally.

Referring to FIG. 11 , when the electronic brake system 1 does not operate normally, each valve is controlled to an initial braking state that is an inoperative state. Then, when the driver presses the brake pedal 10, the first piston 21a connected to the brake pedal 10 advances, and the second piston 22a also advances by the movement of the first piston 21a. . Accordingly, hydraulic pressure is generated in the braking fluid accommodated in the first master chamber 20a and the second master chamber 20b, and the hydraulic pressure generated in the first and second master chambers 20a and 20b is applied to the first and second master chambers 20a and 20b. 2 is transmitted to the wheel cylinder 40 through the backup passages 251 and 252 to implement the braking force.

At this time, the first and second cut valves 261 and 262 provided in the first and second backup passages 251 and 252, and the inlet valves provided in the first and second hydraulic circuits 201 and 202 ( 221) is provided as a normally open type solenoid valve, the simulator valve 54 and the outlet valve 222 are provided as a normally closed type solenoid valve, the master cylinder 20 ), since the hydraulic pressure generated in the first and second master chambers 20a and 20b can be directly transferred to the four wheel cylinders 40, it is possible to achieve rapid braking as well as improvement of braking stability.

Hereinafter, an operation in the inspection mode of the electronic brake system 1 according to the first embodiment of the present invention will be described.

The inspection mode includes a mode for inspecting whether the simulation device 50 is leaking, and a mode for inspecting whether air exists in the master cylinder 20 . The brake system 1 according to an embodiment of the present invention may periodically or frequently inspect whether the device is abnormal by executing the inspection mode before the driver starts driving the vehicle, while the vehicle is stopped, or while driving.

12 is a hydraulic circuit diagram showing a state in which the electromagnetic brake system 1 according to the first embodiment of the present invention checks whether air is present in the leak or the master cylinder 20 of the simulator device 50 .

As described above, when the electronic brake system 1 operates abnormally, the respective valves are controlled to the inactive braking initial state, and the first and second backup passages 251 and 252 installed in the first and second backup passages 251 and 252 are controlled. 2 The cut valves 261 and 262 are opened so that hydraulic pressure can be directly transmitted to the wheel cylinder 40 .

At this time, the simulator valve 54 is provided in a closed state to prevent the hydraulic pressure transmitted to the wheel cylinder 40 through the first backup flow path 251 from leaking to the reservoir 30 through the simulation device 50 . Accordingly, the hydraulic pressure discharged from the master cylinder 20 is transmitted to the wheel cylinder 40 without loss by the driver pressing the brake pedal 10, and is controlled to ensure stable braking.

However, when a leak exists in the simulation chamber 51 or the simulator valve 54 of the simulator device 50 , a part of the hydraulic pressure discharged from the master cylinder 20 is transferred to the reservoir through the simulation chamber 51 or the simulator valve 54 . (30), there is a risk of loss, and as a result, the braking force intended by the driver may not be generated, and thus a problem may occur in braking stability of the vehicle.

Also, the same problem may occur when air is present in the master cylinder 20 . When air is present in the master cylinder 20 , the pedal feeling felt by the driver may be lightened, and when the driver recognizes this as a normal operating state and switches to the fallback mode, braking performance may be deteriorated.

If the hydraulic pressure discharged from the hydraulic pressure supply device 100 flows into the reservoir 30 and a pressure loss occurs, it is difficult to determine whether a leak exists in the simulator device 50 or air exists in the master cylinder 20 . . Therefore, in the inspection mode, the hydraulic circuit connected to the hydraulic pressure supply device 100 may be configured as a closed circuit by closing the simulator valve 54 . In other words, by closing the simulator valve 54 and the outlet valve 222 , the flow path connecting the hydraulic pressure supply device 100 and the reservoir 30 is blocked to form a closed circuit.

The brake system 1 may provide hydraulic pressure only to the first backup passage 251 to which the simulation device 50 is connected among the first and second backup passages 251 and 252 in the inspection mode. Accordingly, in order to prevent the hydraulic pressure discharged from the hydraulic pressure supply device 100 from being transferred to the master cylinder 20 along the second backup flow path 252 , the second cut valve 262 may be switched to a closed state. In addition, by controlling the fourth control valve 234 connecting the first hydraulic circuit 201 and the second hydraulic circuit 202 in a closed state, the hydraulic pressure in the first pressure chamber 112 is increased in the second pressure chamber 113 . ) to prevent leakage.

Referring to FIG. 12 , in the inspection mode, the respective valves of the electromagnetic brake system 1 according to the first embodiment of the present invention are controlled to an initial braking state in which they are not in operation, and the second to fourth inlet valves 221b and 221c are controlled. , 221d) and the second cut valve 262 are switched to a closed state, and the first inlet valve 221a and the first cut valve 261 to which the first backup flow path 251 is connected at the rear end are maintained in an open state. Thus, the hydraulic pressure generated in the hydraulic pressure supply device 100 may be transferred to the master cylinder 20 .

By controlling the second cut valve 262 in the closed state, the hydraulic pressure of the hydraulic pressure supply device 100 can be prevented from being discharged along the second backup flow path 252 , and by switching the simulator valve 54 to the closed state It is possible to prevent the hydraulic pressure transmitted from the hydraulic pressure supply device 100 to the master cylinder 20 from leaking into the reservoir 30 through the simulator device 50 and the first reservoir flow path 61 .

In the inspection mode, the electronic control unit generates hydraulic pressure through the hydraulic pressure supply device 100 , and then analyzes the pressure value of the master cylinder 20 measured by the backup flow path pressure sensor PS1 to cause leakage of the simulation device 50 . It is possible to determine the presence or the presence of air in the master cylinder 20 . For example, when there is no loss as a result of the measurement of the backup flow pressure sensor PS1, there is no leakage in the simulator chamber 51 or the simulator valve 54 of the simulation device 50, or air in the master cylinder 20 It is determined that it does not exist, and when a loss occurs, it may be determined that a leak exists in the simulation device 50 or that air exists in the master cylinder 20 .

Furthermore, the electronic brake system 1 according to the first embodiment of the present invention may perform a balance mode for balancing the first pressure chamber 112 and the second pressure chamber 113 . The balance mode may be performed when the pressures of the first pressure chamber 112 and the second pressure chamber 113 are not balanced. For example, when a leak occurs due to repeated operation of the hydraulic pressure supply device 100 or an ABS operation occurs suddenly, the pressure balance between the first pressure chamber 112 and the second pressure chamber 113 is broken, and accordingly, the hydraulic pressure The piston 114 is not in the calculated position, which may result in malfunction.

In the balance mode, the first and second pressure chambers 112 and 113 of the pressure providing unit 110 may communicate with each other to balance the pressure, and a balancing process may be performed. The electronic control unit detects the hydraulic pressure of the first hydraulic circuit 201 and the hydraulic pressure of the second hydraulic circuit 202 by the flow path pressure sensors PS21 and PS22 to determine whether the pressure is imbalanced.

For example, when the pressure of the first pressure chamber 112 is greater than the pressure of the second pressure chamber 113 , the first pressure chamber 112 and the second pressure chamber 113 are communicated to each other to communicate with the first pressure chamber 112 . ) and the pressure of the second pressure chamber 113 may be balanced.

To this end, in the balance mode, the hydraulic flow path and valve of the hydraulic control unit 200, specifically, the fourth control valve 234 may be controlled in an open state to open the fourth hydraulic flow path 214 . That is, the first pressure chamber 112 and the second pressure chamber 113 may communicate with each other through the first hydraulic oil passage 211 , the second hydraulic oil passage 212 , and the fourth hydraulic oil passage 214 , and thus The pressures of the first pressure chamber 112 and the second pressure chamber 113 may be balanced.

At this time, the first to fourth inlet valves 221 are controlled to be closed and the hydraulic piston 114 may be partially moved forward or backward by operating the motor 120 to quickly perform the balancing mode.

Hereinafter, the electronic brake system 2 according to the second embodiment of the present invention will be described.

In the description of the electronic brake system 2 according to the second embodiment of the present invention to be described below, the electromagnetic brake system 1 according to the first embodiment of the present invention described above, except for cases where separate reference numerals are used and additionally described. ) as the same as the description, and the description is omitted to prevent duplication of content.

13 is a hydraulic circuit diagram showing the electromagnetic brake system 2 according to the second embodiment of the present invention.

Referring to FIG. 13 , the hydraulic control unit 200 is branched from the fourth hydraulic flow path 214 and connected to the third hydraulic line 213 , the seventh hydraulic oil passage 317 , and the seventh hydraulic oil passage 317 . It may be provided to further include an eighth control valve 338 for controlling the flow of the braking fluid.

The seventh hydraulic flow path 317 may be provided by being branched from the front end of the fourth control valve 234 on the fourth hydraulic flow path 214 and joining the rear end of the third control valve 233 on the third hydraulic flow path 213 . have. In addition, the eighth control valve 338 provided in the seventh hydraulic flow path 317 allows only the braking fluid flow in the direction from the second pressure chamber 113 to the second hydraulic circuit 202, and the braking fluid in the opposite direction. The flow may be provided with a shut-off check valve. That is, the eighth control valve 338 permits the hydraulic pressure generated in the second pressure chamber 113 to be transmitted to the second hydraulic circuit 202 , while the hydraulic pressure in the second hydraulic circuit 202 increases the seventh hydraulic oil. It is possible to prevent leakage into the second pressure chamber 113 through the furnace 317 .

With such a flow path and valve structure, the electromagnetic brake system 2 according to the second embodiment of the present invention can provide braking pressure to the wheel cylinder 40 while the hydraulic piston 114 moves backward. Specifically, when the driver steps on the brake pedal 10 at the beginning of braking, the motor 120 operates to rotate in the opposite direction, and the rotational force of the motor 120 is transferred to the hydraulic pressure providing unit 110 by the power transmission unit 130 . is transmitted, and the hydraulic piston 114 of the hydraulic pressure providing unit 110 moves backward to generate hydraulic pressure in the second pressure chamber 113 . The hydraulic pressure discharged from the second pressure chamber 113 is transmitted to the wheel cylinders 40 provided in each of the four wheels through the first hydraulic circuit 201 and the second hydraulic circuit 202 to generate braking force.

Specifically, the hydraulic pressure provided from the second pressure chamber 113 is applied to the first hydraulic circuit 201 through the fourth hydraulic passage 214 and the second hydraulic passage 212 connected to the second communication hole 111b. It is directly transmitted to the two wheel cylinders 40 provided. At this time, the first and second inlet valves 221a and 221b are provided in an open state, and the first and second outlet valves 222a and 222b are maintained in a closed state to prevent leakage of hydraulic pressure to the reservoir 30 . prevent.

In addition, the hydraulic pressure provided from the second pressure chamber 113 sequentially passes through the fourth hydraulic flow path 214 , the seventh hydraulic flow path 317 , and the third hydraulic flow path 213 connected to the second communication hole 111b. It passes through and is directly transmitted to the wheel cylinder 40 provided in the second hydraulic circuit 202 . At this time, the third and fourth inlet valves 221c and 221d are provided in an open state, and the third and fourth outlet valves 222c and 222d are maintained in a closed state to prevent leakage of hydraulic pressure into the reservoir 30 . prevent.

At this time, the second and fourth control valves 232 and 234 are controlled in an open state to open the second and fourth hydraulic passages 212 and 214 , and the eighth control valve 338 is connected to the second pressure chamber ( 113), since it is provided as a check valve that allows the flow of the braking fluid in the direction of the wheel cylinder 40, the seventh hydraulic flow path 317 is also opened.

In addition, the seventh control valve 237 may be maintained in a closed state to block the sixth hydraulic flow path 216 . This prevents the hydraulic pressure generated in the second pressure chamber 113 from leaking to the first pressure chamber 112 through the sixth hydraulic flow path 216 to improve the pressure increase rate per stroke of the hydraulic piston 114, A quick braking response can be achieved at the beginning of braking.

The third dump valve 243 may be switched to a closed state. As the third dump valve 243 is closed, the hydraulic pressure of the braking fluid can be quickly and stably generated in the second pressure chamber 113, and the hydraulic pressure generated in the second pressure chamber 113 is transferred to the fourth hydraulic flow path ( 514) can be discharged only.

Hereinafter, the electronic brake system 3 according to the third embodiment of the present invention will be described.

In the description of the electronic brake system 3 according to the third embodiment of the present invention to be described below, the electromagnetic brake system 1 according to the first embodiment of the present invention described above, except where additional reference numerals are used to further describe it. ) as the same as the description, and the description is omitted to prevent duplication of content.

14 is a hydraulic circuit diagram showing an electromagnetic brake system 3 according to a third embodiment of the present invention. Referring to FIG. 14 , a first control valve ( 231 and the second control valve 432 may be sequentially provided. The first control valve 231 may be provided as a check valve that allows only the flow of the braking fluid in the direction from the first pressure chamber 112 to the first hydraulic circuit 201 and blocks the flow of the braking fluid in the opposite direction. . That is, the first control valve 231 allows the hydraulic pressure generated in the first pressure chamber 112 to be transmitted to the first hydraulic circuit 201, while the hydraulic pressure in the first hydraulic circuit 201 is transferred to the second hydraulic flow path ( It is possible to prevent leakage into the first pressure chamber 112 through the 212 .

The second control valve 231 may be provided at a front end of a point where a fourth hydraulic flow path 214 to be described later is connected on the second hydraulic flow path 214 . The second control valve 432 may be provided as a two-way control valve that controls the flow of the braking fluid transmitted through the second hydraulic flow path 212 , and the second control valve 432 is normally open. It may be provided as a solenoid valve of a normally open type that operates to close the valve when receiving an electrical signal from the electronic control unit.

The second control valve 432 is provided between the pressure chamber of the hydraulic pressure generator and the wheel cylinder to implement regenerative braking and selectively connects the pressure chamber and the hydraulic circuit so that only a part of the hydraulic pressure of the braking fluid is transmitted to the wheel cylinder. and blocking. For example, as shown in FIG. 1 , the second control valve 432 includes the first pressure chamber 112 and the first wheel cylinder 40 of the rear wheels RL and RR in which the rear wheel regenerative braking is implemented. The first pressure chamber 112 and the first pressure chamber 112 are provided in the second hydraulic flow path 212 between the hydraulic circuits 201 so that only a part of the hydraulic pressure of the braking fluid is transmitted to the rear wheel cylinder 40 of the first hydraulic circuit 201 . 1 It is possible to selectively connect and block the hydraulic circuit 201 . A detailed description thereof will be provided later.

Hereinafter, a rear wheel regenerative braking operation of the electronic brake system 3 according to the third embodiment of the present invention will be described.

15 is a hydraulic circuit diagram illustrating a state in which the hydraulic piston 114 of the electronic brake system 3 advances to provide braking pressure and realizes rear wheel regenerative braking according to the third embodiment of the present invention. Referring to FIG. 15 , as described above, when the driver steps on the brake pedal 10 at the initial stage of braking providing the pressure provided in the low pressure mode, the motor 120 operates to rotate in one direction, and the The rotational force is transmitted to the hydraulic pressure providing unit 110 by the power transmitting unit 130 , and the hydraulic piston 114 of the hydraulic pressure providing unit 110 advances to generate hydraulic pressure in the first pressure chamber 112 . The hydraulic pressure discharged from the first pressure chamber 112 is transmitted to the wheel cylinders 40 provided in each of the four wheels through the first hydraulic circuit 201 and the second hydraulic circuit 202 to generate braking force.

After that, when the electronic control unit determines that the regenerative braking is driven in the rear wheel of the vehicle, specifically, the wheel cylinder 40 of the first hydraulic circuit 201, the electronic control unit controls the driver's required braking pressure and the regenerative braking pressure. The size of the brake fluid pressure calculated according to the difference is calculated, and the first hydraulic circuit 201 can control the second control valve 432 to close after the hydraulic pressure is applied to the rear wheel cylinder 40 by the corresponding pressure level. have. Therefore, the hydraulic pressure of the rear wheel in which the regenerative braking occurs is lower than when the regenerative braking is not driven.

The electronic control unit uses a flow path pressure sensor PS21 that senses the hydraulic pressure of the first hydraulic circuit 201 , and the brake transmitted from the hydraulic pressure supply device 100 to the rear wheel cylinder 40 of the first hydraulic circuit 201 . The hydraulic pressure can be controlled stably. Specifically, the electronic control unit transmits the brake fluid pressure from the hydraulic pressure supply device 100 to the front wheel cylinder 40 of the second hydraulic circuit 202 to which only the hydraulic pressure is transmitted through the flow path pressure sensor PS22. Detected through and compared with the braking fluid pressure delivered to the rear wheel cylinder 40 of the first hydraulic circuit, the rear wheel to be blocked or reduced in the rear wheel cylinder 40 of the first hydraulic circuit 201 during regenerative braking. The brake fluid pressure can be controlled more precisely.

As such, as the electronic control unit controls the operation of the second control valve 432 during regenerative braking of the rear wheel, the braking fluid pressure applied to the rear wheel cylinder 40 of the first hydraulic circuit 201 is applied to the regenerative braking pressure. It can be adjusted stably according to the requirements of the vehicle, thereby uniformly distributing the braking pressure or braking force applied to the four wheels of the vehicle to ensure the vehicle's braking stability and to prevent oversteering or understeering to drive the vehicle. Stability can be improved.

Hereinafter, the electronic brake system 4 according to the fourth embodiment of the present invention will be described.

In the description of the electromagnetic brake system 4 according to the fourth embodiment of the present invention to be described below, except for cases where separate reference numerals are used to further describe the electronic brake system 3 according to the third embodiment of the present invention described above ) as the same as the description, and the description is omitted to prevent duplication of content.

16 is a hydraulic circuit diagram showing the electromagnetic brake system 4 according to the fourth embodiment of the present invention.

Referring to FIG. 16 , the hydraulic control unit 200 is branched from the fourth hydraulic oil passage 214 and connected to the third hydraulic line 213 and a seventh hydraulic oil passage 517 and a seventh hydraulic oil passage 517 . It may be provided to further include an eighth control valve 538 for controlling the flow of the braking fluid.

The seventh hydraulic flow path 517 may be provided by being branched from the front end of the fourth control valve 234 on the fourth hydraulic flow path 214 and joining the rear end of the third control valve 233 on the third hydraulic flow path 213 . have. In addition, the eighth control valve 538 provided in the seventh hydraulic flow path 517 allows only the braking fluid flow in the direction from the second pressure chamber 113 to the second hydraulic circuit 202, and the braking fluid in the opposite direction. The flow may be provided with a shut-off check valve. That is, the eighth control valve 538 permits the hydraulic pressure generated in the second pressure chamber 113 to be transmitted to the second hydraulic circuit 202 , while the hydraulic pressure in the second hydraulic circuit 202 increases the pressure of the seventh hydraulic oil. It is possible to prevent leakage into the second pressure chamber 113 through the furnace 517 .

With such a flow path and valve structure, the electromagnetic brake system 2 according to the second embodiment of the present invention can provide braking pressure to the wheel cylinder 40 while the hydraulic piston 114 moves backward. Specifically, when the driver steps on the brake pedal 10 at the beginning of braking, the motor 120 operates to rotate in the opposite direction, and the rotational force of the motor 120 is transferred to the hydraulic pressure providing unit 110 by the power transmission unit 130 . is transmitted, and the hydraulic piston 114 of the hydraulic pressure providing unit 110 moves backward to generate hydraulic pressure in the second pressure chamber 113 . The hydraulic pressure discharged from the second pressure chamber 113 is transmitted to the wheel cylinders 40 provided in each of the four wheels through the first hydraulic circuit 201 and the second hydraulic circuit 202 to generate braking force.

Specifically, the hydraulic pressure provided from the second pressure chamber 113 is applied to the first hydraulic circuit 201 through the fourth hydraulic passage 214 and the second hydraulic passage 212 connected to the second communication hole 111b. It is directly transmitted to the two wheel cylinders 40 provided. At this time, the first and second inlet valves 221a and 221b are provided in an open state, and the first and second outlet valves 222a and 222b are maintained in a closed state to prevent leakage of hydraulic pressure to the reservoir 30 . prevent.

In addition, the hydraulic pressure provided from the second pressure chamber 113 sequentially flows through the fourth hydraulic passage 214 , the seventh hydraulic passage 517 , and the third hydraulic passage 213 connected to the second communication hole 111b. It passes through and is directly transmitted to the wheel cylinder 40 provided in the second hydraulic circuit 202 . At this time, the third and fourth inlet valves 221c and 221d are provided in an open state, and the third and fourth outlet valves 222c and 222d are maintained in a closed state to prevent leakage of hydraulic pressure into the reservoir 30 . prevent.

At this time, the fourth control valve 234 is controlled in an open state to open the fourth hydraulic flow path 214 , and the eighth control valve 538 moves from the second pressure chamber 113 to the wheel cylinder 40 direction. Since it is provided as a check valve that allows the flow of the braking fluid, the seventh hydraulic flow path 517 is also opened.

In addition, the seventh control valve 237 may be maintained in a closed state to block the sixth hydraulic flow path 216 . This prevents the hydraulic pressure generated in the second pressure chamber 113 from leaking to the first pressure chamber 112 through the sixth hydraulic flow path 216 to improve the pressure increase rate per stroke of the hydraulic piston 114, A quick braking response can be achieved at the beginning of braking.

The third dump valve 243 may be switched to a closed state. As the third dump valve 243 is closed, the hydraulic pressure of the braking fluid can be quickly and stably generated in the second pressure chamber 113, and the hydraulic pressure generated in the second pressure chamber 113 is transferred to the fourth hydraulic flow path ( 514) can be discharged only.

10: brake pedal 11: pedal displacement sensor
20: master cylinder 30: reservoir
40: wheel cylinder 50: simulation device
54: simulator valve 60: inspection valve
100: hydraulic pressure supply unit 110: hydraulic pressure supply unit
120: motor 130: power conversion unit
200: hydraulic control unit 201: first hydraulic circuit
202: second hydraulic circuit 211: first hydraulic flow path
212: second hydraulic flow path 213: third hydraulic flow path
214: fourth hydraulic flow path 215: fifth hydraulic flow path
216: 6th hydraulic flow path 317, 517: 7th hydraulic flow path
221: inlet valve 222: outlet valve
231: first control valve 232, 432: second control valve
233: third control valve 234: fourth control valve
235: fifth control valve 236: sixth control valve
237: seventh control valve 338, 538: eighth control valve
241: first dump valve 242: second dump valve
243: third dump valve 251: first backup flow path
252: second backup flow path 261: first cut valve
262: second cut valve

Claims (13)

A first pressure chamber to generate hydraulic pressure by operating a hydraulic piston by an electrical signal output in response to the displacement of the brake pedal, provided at one side of the hydraulic piston movably accommodated in the cylinder block and connected to one or more wheel cylinders and a second pressure chamber provided on the other side of the hydraulic piston and connected to one or more wheel cylinders;
a hydraulic control unit including a first hydraulic circuit for controlling the hydraulic pressure transmitted to the two wheel cylinders and a second hydraulic circuit for controlling the hydraulic pressure transferred to the other two wheel cylinders;
a reservoir in which braking fluid is stored;
a master cylinder having a first master chamber and a first piston provided in the first master chamber, the master cylinder discharging a braking fluid by a pressing force of the brake pedal;
a simulation apparatus comprising a simulation chamber and a reaction force piston provided in the simulation chamber, the simulation apparatus receiving the braking fluid discharged from the first master chamber and providing a reaction force to the pedal effort of the brake pedal;
a reservoir flow path for communicating the first master chamber, a rear end of the simulation chamber, and the reservoir;
a simulator check valve provided in the reservoir flow path and allowing only the flow of the braking fluid from the reservoir to the first master chamber and the flow of the braking fluid from the reservoir to the rear end of the simulation chamber; and
Provided in a bypass flow path connected in parallel to the simulator check valve on the reservoir flow path to control the flow of braking fluid, the flow of braking fluid in both directions between the reservoir and the first master chamber and between the reservoir and the simulation chamber A simulator valve that controls the flow of braking fluid in both directions between the rear ends;
The hydraulic control unit
A first hydraulic oil passage communicating with the first pressure chamber, second and third hydraulic oil passages branched from the first hydraulic oil passage and connected to the first and second hydraulic circuits, respectively, and the second pressure chamber communicate with each other, A fourth hydraulic oil passage connected to the second hydraulic oil passage, a fifth hydraulic oil passage connecting the second hydraulic oil passage and the third hydraulic oil passage, and a sixth hydraulic oil connecting the second hydraulic oil passage and the fifth hydraulic oil passage furnace, first and second control valves provided in the second hydraulic flow path to control the flow of the braking fluid, a third control valve provided in the third hydraulic flow path to control the flow of the braking fluid, and the fourth hydraulic oil a fourth control valve provided in the furnace to control the flow of the braking fluid; a fifth control valve provided on the fifth hydraulic flow path between a point where the sixth hydraulic flow passage is connected and a point where the second hydraulic flow passage is connected; An electromagnetic brake system comprising: a sixth control valve provided between a point where the sixth hydraulic oil passage is connected and a point where the third hydraulic oil passage is connected on a fifth hydraulic oil passage; and a seventh control valve provided in the sixth hydraulic oil passage. According to claim 1,
The second control valve is
An electromagnetic brake system provided at a rear end of a point where the fourth hydraulic flow path is connected on the second hydraulic flow path. According to claim 1,
The second control valve is
An electromagnetic brake system provided at a front end of a point where the fourth hydraulic flow path is connected on the second hydraulic flow path. 4. The method of claim 2 or 3,
The second, fourth, and seventh control valves are provided as solenoid valves for controlling the flow of the braking fluid in both directions,
The first control valve is provided as a check valve that allows only the flow of the braking fluid in the direction from the first pressure chamber to the first hydraulic circuit,
The third control valve is provided as a check valve that allows only the flow of the braking fluid in the direction from the first pressure chamber to the second hydraulic circuit,
The fifth control valve is provided as a check valve that allows only the flow of the braking fluid in a direction from the second hydraulic passage to a point where the sixth hydraulic passage is connected,
and the sixth control valve is provided as a check valve that allows only the flow of the braking fluid in a direction from the third hydraulic passage to a point where the sixth hydraulic passage is connected. 5. The method of claim 4,
The hydraulic control unit
The electromagnetic brake system further comprising: a seventh hydraulic passage branched from a front end of the fourth control valve on the fourth hydraulic oil passage and connected to the third hydraulic oil passage; and an eighth control valve provided in the seventh hydraulic oil passage. 6. The method of claim 5,
and the eighth control valve is provided as a check valve that allows only the flow of the braking fluid in a direction from the second pressure chamber to the second hydraulic circuit. 7. The method of claim 6,
a generator provided in the two wheel cylinders of the first hydraulic circuit; and
The electronic brake system further comprising an electronic control unit controlling the valves based on hydraulic pressure information and displacement information of the brake pedal. 8. The method of claim 7,
Further comprising a pedal displacement sensor for detecting the displacement of the brake pedal,
The electronic control unit
When the pedal displacement sensor detects the displacement of the brake pedal, control to open the second and seventh control valves,
An electronic brake system that controls to close the second control valve during regenerative braking by the generator. 9. The method of claim 8,
Further comprising a flow path pressure sensor for sensing the hydraulic pressure of at least one of the first hydraulic circuit and the second hydraulic circuit,
The electronic control unit
When the hydraulic pressure sensed by the flow path pressure sensor is higher than a preset pressure level, the fourth control valve is opened to supply at least a portion of the braking fluid discharged from the first pressure chamber to the second pressure chamber. system. 10. The method of claim 9,
The master cylinder
The electronic brake system further comprising a second master chamber and a second piston provided in the second master chamber. 11. The method of claim 10,
a first backup passage connecting the first master chamber and the first hydraulic circuit;
a second backup passage connecting the second master chamber and the second hydraulic circuit;
a first cut valve selectively opening and closing the first backup flow path; and
Further comprising a second cut valve for selectively opening and closing the second backup flow path,
The first and second hydraulic circuits include a plurality of inlet valves provided on the upstream side of each wheel cylinder to selectively open and close the flow path,
At least one of the first backup flow path and the second backup flow path connects the first or second master chamber to a downstream side of any one of the plurality of inlet valves. 12. The method of claim 11,
a first dump passage connecting the first pressure chamber and the reservoir;
a second dump passage connecting the second pressure chamber and the reservoir;
a first dump valve provided in the first dump flow path to control the flow of the braking fluid, but provided as a check valve for allowing only the flow of the braking fluid in a direction from the reservoir to the first pressure chamber;
a second dump valve provided in the second dump flow path to control the flow of the braking fluid and provided as a check valve for allowing only the flow of the braking fluid in a direction from the reservoir to the second pressure chamber; and
Provided in a bypass flow path connected in parallel to the second dump valve on the second dump flow path to control the flow of the braking fluid, and to control the flow of the braking fluid in both directions between the reservoir and the second pressure chamber Electronic brake system further comprising a third dump valve provided as a solenoid valve. 13. The method of claim 12,
The first hydraulic circuit includes first and second inlet valves respectively controlling the hydraulic pressure supplied to the two wheel cylinders, and first and second outlet valves controlling the hydraulic pressure discharged from the two wheel cylinders to the reservoir, respectively. including,
The second hydraulic circuit includes third and fourth inlet valves for controlling hydraulic pressure supplied to the other two wheel cylinders, respectively, and third and fourth outlets for controlling hydraulic pressure discharged from the other two wheel cylinders to the reservoir, respectively. Electronic brake system with valve.

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