JP2014019247A - Vehicular brake control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a brake operation feeling at the time of rapid starting.
When a pedal switch is turned on, a brake ECU is rapidly activated, and starts control of wheel cylinder pressure with a master cut valve and a simulator cut valve closed (S11 to S12). When the master cylinder pressure Pm exceeds the threshold value Pmref, the simulator cut valve is operated at a predetermined duty ratio (S13 to S14). As a result, the simulator cut valve is opened with the degree of opening being reduced, and the working fluid flows from the master cylinder to the stroke simulator. As a result, an appropriate pedal stroke can be obtained with respect to the pedaling force on the brake pedal, and the feeling of the stepping on the board given to the driver can be mitigated.

Description

  The present invention relates to a vehicle brake control device that controls the hydraulic pressure of a wheel cylinder by electronic control.

  Conventionally, a brake for a vehicle that connects a power hydraulic pressure source and a wheel cylinder via a linear control valve and controls the hydraulic pressure of the wheel cylinder to a target hydraulic pressure by controlling the opening of the linear control valve by an electronic control device. Control devices are known. In such a vehicle brake control device, a control hydraulic pressure circuit that supplies hydraulic fluid from a power hydraulic pressure source to a wheel cylinder and a hydraulic fluid that is generated from a master cylinder that generates hydraulic pressure by an operation force input to a brake pedal are supplied to the wheel cylinder. And a master hydraulic circuit for supplying. The master hydraulic circuit is provided with a master cut valve that is a normally open solenoid valve. The master cylinder is connected to a stroke simulator that allows inflow of hydraulic fluid from the master cylinder. A simulator cut valve, which is a normally closed solenoid valve, is provided in the simulator passage connecting the master cylinder and the stroke simulator.

  The electronic control device is activated by power being supplied by turning on an ignition switch or turning on a courtesy switch that detects opening / closing of a vehicle door. When activated, the electronic control device closes the master cut valve and opens the simulator cut valve, and linear control valves (linear control valve for pressure increase and linear on the decompression side) so that the hydraulic pressure of the wheel cylinder becomes the target hydraulic pressure. Control of the control valve) is started. At this time, although the master hydraulic circuit is shut off, the simulator cut valve is kept open, so that the hydraulic fluid can flow out from the master cylinder toward the stroke simulator by operating the brake pedal, The pedal stroke can be operated, and an operation reaction force that increases as the amount of depression of the brake pedal increases can be obtained. When the ignition switch is turned off, the power supply to the electronic control unit is stopped to suppress the battery power consumption, the energization of the master cut valve and the simulator cut valve is stopped, and the master cut valve is closed. Then, the simulator cut valve is opened and the operation of the power hydraulic pressure source is stopped.

  Patent Document 1 describes a technology for starting an electronic control device when an operation of a brake pedal is detected even when an ignition switch is in an off state. The activation of the electronic control device upon detection of the operation of the brake pedal is called rapid activation. When the brake pedal is stepped on when the electronic control unit is not activated, the simulator cut valve is in the closed state, so that the brake operation feeling is somewhat hard unlike the normal brake stroke. When the electronic control unit is activated with the brake pedal depressed and the simulator cut valve is opened, the impression returns to the normal brake stroke (relatively soft brake operation feeling) and the brake pedal enters the driver. Will be given. Therefore, in the brake control device proposed in Patent Document 1, at the time of rapid start-up, it is difficult to enter the brake pedal, and the master cut valve is kept closed while the simulator cut valve is kept closed. A configuration that performs hydraulic pressure control using a control valve is employed.

JP 2004-268868 A

  However, in the brake control device proposed in Patent Document 1, the master cylinder and the wheel cylinder are shut off by the master cut valve and the simulator cut valve is maintained in the closed state at the time of rapid startup. The amount of hydraulic fluid that can be delivered from the cylinder becomes very small, and the hydraulic rigidity just below the brake pedal increases. As a result, the pedal stroke is reduced with respect to the depression force applied to the brake pedal, and the driver feels uncomfortable.

  The present invention has been made to solve the above-described problems, and an object thereof is to improve the brake operation feeling at the time of rapid activation.

A feature of the present invention that solves the above problems is that a plurality of wheel cylinders (82) that are provided in each of a plurality of wheels and receive the hydraulic pressure of hydraulic fluid to apply a braking force to the wheels, and an operating force input to a brake pedal Is connected to the master cylinder, and is sent from the master cylinder and operated by the master cylinder (20) that generates the hydraulic pressure by the power, the power hydraulic pressure source (30) that generates the hydraulic pressure regardless of the operation of the brake pedal. A stroke simulator (71) that allows inflow of liquid and generates a reaction force according to the amount of brake operation, pedal operation detection means (101, 102, 52R, 52L) that detects the brake pedal operation, and the plurality of wheels While the cylinder is disconnected from the master cylinder, the target hydraulic pressure is supplied from the power hydraulic pressure source while operating the stroke simulator. An electronic control device (40, 100) for controlling the hydraulic pressure of the wheel cylinder so as to be applied to the wheel cylinder, and a rapid starting means (100c, S11) for starting the electronic control device when a brake pedal is operated And the vehicle is maintained in a state where the master cylinder and at least a part of the plurality of wheel cylinders communicate with each other when the function of the stroke simulator is stopped in a state where the electronic control unit is not activated In the brake control device of
When the electronic control unit is activated by the rapid activation means, the wheel cylinder and the master cylinder are disconnected from each other and the hydraulic pressure control of the wheel cylinder is performed while the function of the stroke simulator is stopped. When the rapid activation control means (S12) that starts the operation and the operation related value that changes in conjunction with the operation of the brake pedal after the operation of the rapid activation time control means has exceeded a preset reference range Pedal depression rigidity control means (S13, S14, S24, S34, S44, S141, S142, S241, S242) for communicating the wheel cylinder and the master cylinder or for enabling the stroke simulator. Be prepared.

  In the present invention, when the electronic control unit is activated, the wheel cylinder is configured such that the target hydraulic pressure is applied from the power hydraulic pressure source to the wheel cylinder while operating the stroke simulator in a state where the plurality of wheel cylinders are disconnected from the master cylinder. Perform hydraulic pressure control. For example, the electronic control unit detects by a hydraulic pressure control valve that adjusts the wheel cylinder pressure, a hydraulic pressure sensor that detects the hydraulic pressure of the wheel cylinder, a valve driving circuit, a driving circuit that controls driving of the hydraulic power source, and a hydraulic pressure sensor. A microcomputer or the like that controls the hydraulic pressure control valve based on the wheel cylinder pressure and the target hydraulic pressure may be provided. The electronic control device is normally activated by turning on the ignition switch. However, in the present invention, the electronic control device is provided with a rapid activation means, and is configured to be activated even when the brake pedal is operated. Further, when the electronic control unit is not activated, the master cylinder and at least a part of the plurality of wheel cylinders are maintained in communication with the function of the stroke simulator being stopped.

  The electronic control device includes rapid starting control means and pedal depression rigidity control means. When the electronic control unit is activated by the rapid activation means (referred to as rapid activation), the rapid activation control means shuts off the communication between the wheel cylinder and the master cylinder while the function of the stroke simulator is stopped. Start hydraulic pressure control. When rapid activation is performed, the amount of hydraulic fluid that can be delivered from the master cylinder becomes very small, and the hydraulic rigidity just below the brake pedal increases. There is no problem when the amount of pedal operation is small, but when the amount of pedal operation is large, the pedal stroke becomes small with respect to the depressing force on the brake pedal, and the driver feels uncomfortable.

  Therefore, in the present invention, when the pedal depression rigidity control means starts operating the rapid start time control means, and the operation related value that changes in conjunction with the operation of the brake pedal exceeds a preset reference range, The wheel cylinder and the master cylinder are communicated with each other, or the stroke simulator is made operable. As a result, the working fluid flows from the master cylinder to the wheel cylinder or from the master cylinder to the stroke simulator. Therefore, an appropriate pedal stroke can be obtained with respect to the depressing force on the brake pedal, and the brake operation feeling can be improved.

  Another feature of the present invention is that the wheel cylinder and the master cylinder are connected via a normally open valve (46, 47), and the stroke simulator and the master cylinder are connected via a normally closed valve (72). The pedal depression rigidity control means opens the normally open valve to a state in which the opening degree is reduced by the energization control of the normally open valve to communicate the wheel cylinder and the master cylinder ( S24, S242), or opening the normally closed valve to a state in which the opening degree is reduced by energization control of the normally closed valve to enable the stroke simulator (S14, S34, S44, S142). It is in.

  In the present invention, since the wheel cylinder and the master cylinder are connected via a normally open valve, the wheel cylinder and the master cylinder communicate with each other when the electronic control unit is not activated. In addition, since the stroke simulator and the master cylinder are connected via a normally closed valve, the stroke simulator and the master cylinder are not in communication when the electronic control unit is not activated. Is in a stopped state. At the time of rapid activation, the rapid activation time control means closes the normally open valve to cut off the communication between the wheel cylinder and the master cylinder and starts the hydraulic pressure control of the wheel cylinder. The pedal depression rigidity control means narrows the opening degree of the normally open valve by the energization control of the normally open valve when the operation related value that changes in conjunction with the operation of the brake pedal exceeds a preset reference range. The wheel cylinder and the master cylinder are brought into communication with each other, or the normally closed valve is opened to a state in which the opening degree is reduced by energization control of the normally closed valve, so that the stroke simulator can be operated. Therefore, the amount of hydraulic fluid delivered from the master cylinder can be made appropriate, and the brake operation feeling can be further improved.

  Another feature of the present invention is that the pedal depression rigidity control means (S34, S44) gradually increases the degree of opening of the normally closed valve by energization control of the normally closed valve. This is to increase the speed at which the opening degree is increased as the stepping amount or the stepping force is increased.

  In the present invention, when the pedal depression rigidity control means makes the stroke simulator operable, the opening degree of the normally closed valve provided between the master cylinder and the stroke simulator is gradually increased. Thereby, a stroke simulator can be made to function gradually and a sudden change of brake operation feeling can be prevented. Further, the pedal depression rigidity control means increases the speed at which the opening degree is increased as the operation amount (depression amount or depression force) of the brake pedal is increased. Thereby, the larger the amount of operation of the brake pedal, the faster the function of the stroke simulator can be obtained. As a result, it is possible to create an appropriate pedal reaction force according to the pedal depression force of the driver, and to further improve the pedal operation feeling.

  Another feature of the present invention is that the pedal depression rigidity control means includes a storage means (100a) for storing reference data representing a relationship between a depression amount and a depression force of the brake pedal set in advance, and the actual brake Actual data acquisition means (101, 52) for acquiring actual data representing the depression amount and depression force of the pedal, the relationship between the depression amount and the depression force of the brake pedal represented by the actual data, and the reference data The degree of opening of the normally open valve or the normally closed valve is controlled so that the degree of difference (e) between the amount of depression of the brake pedal and the depression force represented by is reduced (S141, S142, S241, S242). ) That is.

  In this case, the degree of difference may be represented by a deviation (e = Pm−Pmref) between the depression force (Pmref) represented by the reference data with respect to the actual depression amount of the brake pedal and the actual depression force (Pm). .

  In the present invention, the storage means stores reference data representing a relationship between a predetermined depression amount of the brake pedal and a depression force. This reference data may be set, for example, in relation to normal time (during hydraulic pressure control in which the stroke simulator is functioning). Further, actual data acquisition means acquires actual data representing the actual depression amount and depression force of the brake pedal. The pedal depression rigidity control means reduces the degree of difference between the relationship between the brake pedal depression amount and the depression force represented by the actual data and the relationship between the brake pedal depression amount and the depression force represented by the reference data. The opening degree of the normally open valve or the normally closed valve is controlled. For example, a depression amount detecting means for detecting the depression amount of the brake pedal and a depression force detection means for detecting the depression force of the brake pedal are provided, and the depression of the brake pedal during the hydraulic pressure control after the rapid activation is performed by these detection means. Detect amount and stepping force. Then, a deviation between the depression force represented by the reference data with respect to the detected depression amount of the brake pedal and the detected depression force is calculated, and this deviation is set as a difference degree. Alternatively, a deviation between the depression amount represented by the reference data with respect to the detected depression force of the brake pedal and the detected depression amount may be calculated, and this deviation may be used as the degree of difference.

  The greater the degree of difference, the more different the brake operation feeling compared to normal times. Therefore, the pedal depression rigidity control means controls the opening degree of the normally open valve or the normally closed valve so as to reduce the degree of difference. As a result, the relationship between the depression amount of the brake pedal and the depression force does not change much from the normal time. Therefore, a good brake operation feeling can be obtained.

  Another feature of the present invention is that the operation-related value that changes in conjunction with the operation of the brake pedal is a depression amount of the brake pedal.

  In the present invention, when the depression amount of the brake pedal exceeds the reference range, that is, when the depression amount exceeds the threshold value, the wheel cylinder and the master cylinder are communicated or the stroke simulator is made operable. Accordingly, pedal depression rigidity control (hydraulic rigidity control immediately below the brake pedal) can be started at an appropriate timing.

  Another feature of the present invention is that the operation-related value that changes in conjunction with the operation of the brake pedal is a depression force of the brake pedal.

  In the present invention, when the depression force of the brake pedal exceeds the reference range, that is, when the depression force exceeds a threshold value, the wheel cylinder and the master cylinder are communicated or the stroke simulator is made operable. Therefore, pedal depression rigidity control can be started at an appropriate timing.

  Another feature of the present invention is that the operation-related value that changes in conjunction with the operation of the brake pedal includes a preset relationship between a depression amount and a depression force of the brake pedal, and an actual depression amount of the brake pedal. It is a value representing the degree of difference between the relationship between and the stepping force.

  In the present invention, a value representing a degree of difference between a preset relationship between the depression amount and the depression force of the brake pedal and an actual relationship between the depression amount and the depression force of the brake pedal is acquired, and this difference degree is obtained. It is used as an operation-related value that changes in conjunction with the operation of the brake pedal. When the value indicating the degree of difference exceeds the reference range, that is, when the value indicating the degree of difference exceeds a threshold value, the wheel cylinder and the master cylinder are communicated or the stroke simulator is made operable. Accordingly, pedal depression rigidity control (hydraulic rigidity control immediately below the brake pedal) can be started at an appropriate timing.

Another feature of the present invention is that a plurality of wheel cylinders (82) provided on each of a plurality of wheels to receive a hydraulic pressure of the hydraulic fluid to apply a braking force to the wheels, and a hydraulic pressure by an operation force input to the brake pedal. Is connected to the master cylinder, and is supplied from the master cylinder and flows in hydraulic fluid. The master cylinder (20) generates the hydraulic pressure, the power hydraulic pressure source (30) generates the hydraulic pressure regardless of the operation of the brake pedal. A stroke simulator (71) that generates a reaction force according to the amount of brake operation, pedal operation detection means (101, 102, 52R, 52L) that detects the brake pedal operation, and the plurality of wheel cylinders While the stroke simulator is operated while being disconnected from the master cylinder, the target hydraulic pressure is supplied from the power hydraulic pressure source to the wheel system. An electronic control device (40, 100) for controlling the hydraulic pressure of the wheel cylinder so as to be applied to the vehicle, and rapid starting means (100c, S11) for starting the electronic control device when a brake pedal is operated. In a state where the electronic control unit is not activated, the brake of the vehicle is maintained such that the master cylinder and at least a part of the plurality of wheel cylinders communicate with each other while the function of the stroke simulator is stopped. In the control device,
When the electronic control unit is activated by the rapid activation means, the wheel cylinder and the master cylinder are disconnected from each other and the hydraulic pressure control of the wheel cylinder is performed while the function of the stroke simulator is stopped. After the rapid activation control means (S12) for starting the operation and the rapid activation control means start operation, the wheel cylinder and the master cylinder are communicated with a reduced degree of opening, or the stroke simulator and the There is provided pedal depression rigidity control means (S14, S24, S34, S44, S141, S142, S241, S242) for communicating with the master cylinder in a state in which the opening degree is reduced.

  In the present invention, when the rapid activation control means is activated, the fluid pressure control of the wheel cylinder is started by interrupting the communication between the wheel cylinder and the master cylinder in a state where the function of the stroke simulator is stopped. . The pedal depression rigidity control means causes the wheel cylinder and the master cylinder to communicate with each other with the opening degree reduced after the rapid start-up control means starts operating, or the stroke simulator and the master cylinder reduce the opening degree. Communicate in the state. Thereby, an appropriate amount of hydraulic fluid flows from the master cylinder to the wheel cylinder or from the master cylinder to the stroke simulator. Therefore, an appropriate pedal stroke can be obtained with respect to the depressing force on the brake pedal, and the brake operation feeling can be improved.

  Note that “the wheel cylinder and the master cylinder communicate with each other while the opening degree is reduced” means that the opening degree is reduced compared to the communication opening degree between the wheel cylinder and the master cylinder when the electronic control unit is not activated. This means that the wheel cylinder and the master cylinder communicate with each other. In addition, “the stroke simulator and the master cylinder communicate with each other with a reduced opening degree” means that the communication opening degree between the stroke simulator and the master cylinder in normal hydraulic pressure control (hydraulic pressure control performed while the stroke simulator is functioning). This means that the stroke simulator and the master cylinder are communicated with each other in a state in which the opening degree is reduced.

  In the above description, in order to help the understanding of the invention, the reference numerals used in the embodiments are attached to the configuration of the invention corresponding to the embodiment in parentheses, but each constituent element of the invention is the reference numeral. It is not limited to the embodiment defined by.

1 is a schematic system configuration diagram of a vehicle brake control device according to an embodiment. 4 is a flowchart illustrating a pedal depression rigidity control routine according to the first embodiment. 6 is a flowchart illustrating a pedal depression rigidity control routine according to a second embodiment. It is a graph showing the relationship between a pedal stroke and a master cylinder pressure. It is a flowchart showing the characteristic part of the pedal depression rigidity control routine which concerns on the modification 1 of duty ratio control. It is a flowchart showing the characteristic part of the pedal depression rigidity control routine which concerns on the modification 2 of duty ratio control. It is a flowchart showing the characteristic part of the pedal depression rigidity control routine which concerns on the modification 3 of duty ratio control. It is a flowchart showing the characteristic part of the pedal depression rigidity control routine which concerns on the modification 4 of duty ratio control.

  Hereinafter, a vehicle brake control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic system configuration diagram of a vehicle brake control device according to the present embodiment.

  The brake control device of the present embodiment includes a brake pedal 10, a master cylinder 20, a power hydraulic pressure generator 30, a brake actuator 40, a reservoir 60, a stroke simulator device 70, and a disc brake provided on each wheel. Units 80FR, 80FL, 80RR, and 80RL, and a brake ECU 100 that is an electronic control unit that performs brake control are provided.

  The disc brake units 80FR, 80FL, 80RR, 80RL include brake discs 81FR, 81FL, 81RR, 81RL and wheel cylinders 82FR, 82FL, 82RR, 82RL built in the brake caliper. In addition, about the structure provided for every wheel, although FR is attached to the end of the code | symbol, FR is attached to the left front wheel, RR is attached to the right rear wheel, RL is attached to the left rear wheel, When the wheel position is not specified, the last symbol is omitted. Further, as necessary, the wheel cylinders 82FR and 82FL provided on the front wheel side are referred to as a front wheel cylinder 82F, and the wheel cylinders 82RR and 82RL provided on the rear wheel side are referred to as a rear wheel cylinder 82R.

  The wheel cylinders 82FR, 82FL, 82RR, and 82RL are connected to the brake actuator 40, and the brake discs 81FR, 81FL, 81RR, and 81RL that rotate together with the wheels by the hydraulic pressure of the hydraulic fluid supplied from the brake actuator 40 (brake fluid). Apply braking force to the wheels by pressing the brake pads.

  The master cylinder 20 includes two pressurizing chambers 21 and 22. The pressurizing chambers 21 and 22 are connected to the wheel cylinders 82FR and 82FL on the front wheel side by the master passages 23 and 24. When the brake pedal 10 is depressed, the pressurizing piston moves forward to pressurize the hydraulic fluid. The hydraulic pressure (master cylinder pressure) is transmitted to the wheel cylinders 82FR and 82FL. A reservoir 60 is connected to the pressurizing chambers 21 and 22 of the master cylinder 20. The reservoir 60 stores hydraulic fluid at atmospheric pressure. The master cylinder 20 is configured to allow the flow of hydraulic fluid from the reservoir 60 to the pressure chambers 21 and 22 when the pressurizing piston is retracted, and to block the reverse flow of the hydraulic fluid when the pressurizing piston is advanced. ing.

  A stroke simulator device 70 is connected to one pressurizing chamber 22 of the master cylinder 20. The stroke simulator device 70 includes a stroke simulator 71 and a simulator cut valve 72. The simulator cut valve 72 is a normally closed electromagnetic valve that maintains a closed state by the biasing force of a spring when the solenoid is not energized and opens only when the solenoid is energized. When the simulator cut valve 72 is in the closed state, the flow of hydraulic fluid between the master passage 24 and the stroke simulator 71 is interrupted, and when the simulator cut valve 72 is in the open state, the master passage 24 and the stroke simulator 71 are closed. Is allowed to flow in both directions.

  The stroke simulator 71 includes a plurality of pistons and springs. When the simulator cut valve 72 is in the open state, the stroke simulator 71 is operated by introducing an amount of hydraulic fluid in accordance with the amount of brake operation. And a reaction force according to the pedal operation amount is generated to improve the driver's brake operation feeling.

  The power hydraulic pressure generator 30 is a power hydraulic pressure source, and includes a pump 31 that pumps hydraulic fluid from a reservoir 60 via a suction passage 61, a motor 32 that drives the pump 31, and an accumulator 33. The accumulator 33 converts the pressure energy of the hydraulic fluid pressurized by the pump 31 into the pressure energy of an enclosed gas such as nitrogen and stores it. The power hydraulic pressure generator 30 is connected to the brake actuator 40 and supplies pressurized hydraulic fluid to the brake actuator 40.

  The brake actuator 40 is connected to an accumulator passage 41 to which pressurized hydraulic fluid is supplied from the power hydraulic pressure generator 30, a return passage 42 connected to the reservoir 60, and each wheel cylinder 82FR, 82FL, 82RR, 82RL. The four individual passages 43FR, 43FL, 43RR, 43RL are provided. Further, the brake actuator 40 includes pressure-increasing linear control valves 44FR, 44FL, 44RR, 44RL, and through the pressure-increasing linear control valves 44FR, 44FL, 44RR, 44RL, individual passages 43FR, 43FL, 43RR, 43RL are provided. It is connected to the accumulator passage 41. Further, the brake actuator 40 is provided with pressure reducing linear control valves 45FR, 45FL, 45RR, 45RL, and through the pressure reducing linear control valves 45FR, 45FL, 45RR, 45RL, individual passages 43FR, 43FL, 43RR, 43RL are provided. The return passage 42 is connected. Hereinafter, with respect to the four individual passages 43FR, 43FL, 43RR, 43RL, the four pressure increasing linear control valves 44FR, 44FL, 44RR, 44RL, and the four pressure reducing linear control valves 45FR, 45FL, 45RR, 45RL, any of the front, rear, left and right wheels When it is not necessary to specify the valve, they are simply referred to as an individual passage 43, a pressure-increasing linear control valve 44, and a pressure-decreasing linear control valve 45.

  The pressure-increasing linear control valve 44 and the pressure-decreasing linear control valve 45 have a predetermined fixed relationship between the hydraulic pressure difference between the upstream side and the downstream side and the energization amount to the solenoid, and increase / decrease in the energization amount. This is an electromagnetic control valve whose valve opening pressure changes in response to. Therefore, the pressure-increasing linear control valve 44 and the pressure-decreasing linear control valve 45 can continuously change the wheel cylinder pressure, which is the hydraulic pressure of the wheel cylinder 82, by controlling the energization amount. In the present embodiment, the four pressure-increasing linear control valves 44FR, 44FL, 44RR, 44RL and the front wheel side pressure reducing linear control valves 45FR, 45FL are normally closed electromagnetic control valves, and the rear wheel side pressure reducing valve is used. For the linear control valves 45RR and 45RL, a normally open electromagnetic control valve is used. Accordingly, the four pressure-increasing linear control valves 44FR, 44FL, 44RR, and 44RL are closed when the solenoid is not energized, and are opened at an opening corresponding to the energization amount when the solenoid is energized. The hydraulic fluid pressure generator 30 allows the hydraulic fluid to flow into the wheel cylinders 82FR, 82FL, 82RR, and 82RL, thereby increasing the wheel cylinder pressure. Further, the pressure-reducing linear control valves 45FR and 45FL on the front wheel side are closed when the solenoid is not energized, and when the solenoid is energized, they are opened at an opening degree corresponding to the energization amount. Allowing the hydraulic fluid to flow out of the cylinders 82FR and 82FL into the reservoir 60 allows the wheel cylinder pressure to be reduced. Further, the pressure-reducing linear control valves 45RR and 45RL on the rear wheel side are opened when the solenoid is not energized to allow the hydraulic fluid to flow from the wheel cylinders 82RR and 82RL to the reservoir 60 and to increase the wheel cylinder pressure. When the solenoid is energized, the valve is closed to prevent the hydraulic fluid from flowing from the wheel cylinders 82RR, 82RL to the reservoir 60. In this case, when the solenoid energization amount is small, the pressure-reducing linear control valves 45RR and 45RL are adjusted to the opening degree corresponding to the energization amount without moving the valve body to the valve closing position.

  Accordingly, by controlling the energization of the pressure-increasing linear control valve 44 and the pressure-decreasing linear control valve 45, the state in which the hydraulic fluid is allowed to flow from the power hydraulic pressure generator 30 to the wheel cylinder 82, and the wheel cylinder 82 Switching between a state in which the hydraulic fluid is allowed to flow out to the reservoir 60 and a state in which the hydraulic fluid is not allowed to flow from the power hydraulic pressure generator 30 to the wheel cylinder 82 and from the wheel cylinder 82 to the reservoir 60. It is possible. Thereby, each wheel cylinder pressure can be independently controlled to the target hydraulic pressure.

  As a result, the pressure increasing linear control valve 44FR and the pressure reducing linear control valve 45FR constitute a fluid pressure control valve 50FR for controlling the fluid pressure of the wheel cylinder 82FR, and the pressure increasing linear control valve 44FL and the pressure reducing linear control valve 45FL. Thus, a hydraulic pressure control valve 50FL for controlling the hydraulic pressure of the wheel cylinder 82FL is constituted, and the hydraulic pressure control valve for controlling the hydraulic pressure of the wheel cylinder 82RR by the pressure increasing linear control valve 44RR and the pressure reducing linear control valve 45RR. The hydraulic pressure control valve 50RL for controlling the hydraulic pressure of the wheel cylinder 82RL is configured by the pressure increasing linear control valve 44RL and the pressure reducing linear control valve 45RL. Hereinafter, when the hydraulic control valves 50FR, 50FL, 50RR, and 50RL are not distinguished, they are simply referred to as the hydraulic control valve 50.

  Further, the brake actuator 40 includes two master cut valves 46 and 47, which connects the master passage 23 and the individual passage 43 FR through one master cut valve 46 and through the other master cut valve 47. The master passage 24 and the individual passage 43FL are connected. The two master cut valves 46 and 47 are normally open solenoid valves that maintain the valve open state by the biasing force of the spring when the solenoid is not energized and are closed only when the solenoid is energized. When the master cut valve 46 is in the closed state, the flow of hydraulic fluid between the pressurizing chamber 21 of the master cylinder 20 and the wheel cylinder 82FR is interrupted, and when the master cut valve 46 is in the open state, the master cylinder The flow of hydraulic fluid between the 20 pressurizing chambers 21 and the wheel cylinder 82FR is allowed in both directions. Similarly, when the master cut valve 47 is in the closed state, the flow of hydraulic fluid between the pressurizing chamber 22 of the master cylinder 20 and the wheel cylinder 82FL is blocked, and when the master cut valve 47 is in the open state. The flow of hydraulic fluid between the pressurizing chamber 22 of the master cylinder 20 and the wheel cylinder 82FL is allowed in both directions.

  The brake actuator 40 also includes a relief valve 48 that connects the accumulator passage 41 and the return passage 42. When the hydraulic fluid pressure in the accumulator passage 41 increases abnormally, the brake actuator 40 opens to open the hydraulic fluid. Is returned to the reservoir 60.

  The brake actuator 40 includes an accumulator pressure sensor 51, two master cylinder pressure sensors 52R and 52L, and four wheel cylinder pressure sensors 53FR, 53FL, 53RR, and 53RL. The accumulator pressure sensor 51 is provided in an accumulator passage 41 that is a passage between the power hydraulic pressure generator 30 and each pressure-increasing linear control valve 44, and is an accumulator pressure Pa that is a hydraulic pressure output from the power hydraulic pressure generator 30. Is detected. The master cylinder pressure sensors 52R and 52L are provided in the master passages 23 and 24 between the pressurizing chambers 21 and 22 of the master cylinder 20 and the master cut valves 46 and 47, and are pressurized in the pressurizing chambers 21 and 22. The hydraulic pressure of the working fluid is detected. The hydraulic pressure detected by the master cylinder pressure sensors 52R and 52L is referred to as master cylinder pressure Pm. Wheel cylinder pressure sensors 53FR, 53FL, 53RR, 53RL are provided in the individual passages 43FR, 43FL, 43RR, 43RL, and detect the hydraulic pressures of the wheel cylinders 82FR, 82FL, 82RR, 82RL. The hydraulic pressure detected by the wheel cylinder pressure sensors 53FR, 53FL, 53RR, and 53RL is referred to as wheel cylinder pressure Pw. Hereinafter, the wheel cylinder pressure sensors 53FR, 53FL, 53RR, and 53RL are simply collectively referred to as the wheel cylinder pressure sensor 53 when it is not necessary to specify any of the front, rear, left, and right wheels.

  The power hydraulic pressure generating device 30, the brake actuator 40, and the stroke simulator device 70 are driven and controlled by the brake ECU 100. The brake ECU 100 includes a microcomputer 100a having a CPU, a RAM, a ROM, an input / output interface and the like, a drive circuit 100b having a pump drive circuit, a solenoid valve drive circuit, a sensor drive circuit, and the like, and a microcomputer 100a and a drive circuit 100b. The power supply circuit 100c is configured to supply power from a battery (not shown). The four pressure-increasing linear control valves 44 provided in the brake actuator 40, the four pressure-decreasing linear control valves 45, the two master cut valves 46 and 47, and the simulator cut valve 72 provided in the stroke simulator device 70 are: All are connected to the brake ECU 100, and the open / close state and the opening degree are controlled by a solenoid drive signal output from the drive circuit 100b. Further, the motor 32 provided in the power hydraulic pressure generator 30 is also connected to the brake ECU 100 and driven and controlled by a motor drive signal output from the drive circuit 100b.

  The brake ECU 100 connects the accumulator pressure sensor 51, master cylinder pressure sensors 52R, 52L, and wheel cylinder pressure sensors 53FR, 53FL, 53RR, 53RL, and signals representing the accumulator pressure Pa, the master cylinder pressure Pm, and the wheel cylinder pressure Pw. Enter.

  In addition, a pedal stroke sensor 101, a pedal switch 102, a courtesy switch 103, and an ignition switch 104 are connected to the brake ECU 100. The pedal stroke sensor 101 is a kind of pedal operation detection device, detects a pedal stroke that is the amount of depression of the brake pedal 10, and outputs a signal representing the detected pedal stroke Sp to the microcomputer 100a of the brake ECU 100. The pedal switch 102 is a kind of pedal operation detecting device, and is a switch for turning on a stop lamp (not shown) when the brake pedal 10 is depressed to a set position, and a signal (a pedal indicating a switch state Sw1). Switch signal Sw1) is output to the microcomputer 100a of the brake ECU 100. This pedal switch signal Sw1 is also used as a trigger for rapid activation described later.

  The brake ECU 100 includes both means for detecting the depression amount of the brake pedal and means for detecting the depression force of the brake pedal as means for detecting the operation amount of the brake pedal 10. The depression amount of the brake pedal is detected by the pedal stroke Sp output from the pedal stroke sensor 101, and the depression force of the brake pedal is detected by the master cylinder pressure Pm output from the master cylinder pressure sensors 52R and 52L. Both the depression amount and the depression force of the brake pedal represent the operation amount of the brake pedal.

  Since two master cylinder pressure sensors 52R and 52L are provided, the brake ECU 100 acquires two master cylinder pressures Pm. For example, one of the master cylinder pressures (for example, the one with the larger pressure) is used. The stepping force may be detected based on Pm, for example, the stepping force may be detected based on the average value of the two master cylinder pressures Pm. Hereinafter, the master cylinder pressure sensors 52R and 52L used for detecting the depression force of the brake pedal are referred to as a master cylinder pressure sensor 52, and the master cylinder pressure is referred to as a master cylinder pressure Pm. In the present embodiment, the master cylinder pressure sensor 52 is used as means for detecting the depression force of the brake pedal 10, but a pedal depression force sensor (not shown) that directly detects the force by which the driver steps on the brake pedal 10 is provided. The depression force of the brake pedal may be detected based on the depression force detected by the pedal depression force sensor.

  The courtesy switch 103 is a switch that outputs a signal corresponding to the open / closed state of the door of the vehicle, and outputs a signal representing the switch state Sw2 (referred to as a door switch signal Sw2) to the brake ECU 100. The ignition switch 104 outputs an ignition signal IG for starting the vehicle to various ECUs in the vehicle. The ignition signal IG is also input to the brake ECU 100.

  The brake ECU 100 is activated when electric power is supplied from the power supply circuit 100c to the microcomputer 100a and the drive circuit 100b, and accordingly, the brake actuator 40, the power hydraulic pressure generating device 30, and the stroke simulator device 70 become operable. In other words, the brake control system is in a stopped state when no power is supplied from the power supply circuit 100c, and when power is supplied from the power supply circuit 100c, the microcomputer 100a is activated and starts controlling the drive circuit 100b. Then, the brake actuator 40, the power hydraulic pressure generating device 30, and the stroke simulator device 70 are placed under control.

  The power supply circuit 100c is connected to the ignition switch 104, the courtesy switch 103, and the pedal switch 102. When any one of these switches is turned on from the off state, battery power is supplied to the microcomputer 100a and the drive circuit 100b. Thereby, brake ECU100 starts. The activation of the brake ECU 100 when the ignition switch 104 is turned on or the courtesy switch 103 is turned on when the vehicle door is opened is called normal activation, and when the brake pedal 10 is depressed, the pedal switch 102 is turned on and the brake ECU 100 is activated. Activating is called rapid activation. The power supply circuit 100c supplies battery power to the microcomputer 100a and the drive circuit 100b until the ignition switch 104 is turned off (or until a predetermined time elapses after being turned off) at any start-up. to continue.

  The microcomputer 100a of the brake ECU 100 determines whether the activation is normal activation or rapid activation based on the ignition signal IG, the door switch signal Sw2, and the pedal switch signal Sw1 when the electric power is supplied and the activation is performed. For example, the normal start-time braking control is executed, and if rapid start-up, the rapid start-time braking control is executed. At the time of rapid activation, the microcomputer 100a ends the rapid activation braking control when the brake operation is released, and switches to normal activation braking control.

  Before the brake ECU 100 is activated, the master cut valves 46 and 47 are in an open state, and the simulator cut valve 72 is in a closed state. When the brake ECU 100 is activated, the microcomputer 100a closes the master cut valves 46 and 47 by energization to shut off the master passage and opens the simulator cut valve 72 by energization to open the stroke simulator 71 during normal activation. Make it ready for operation. Further, the microcomputer 100a operates the power hydraulic pressure generator 30 to read the accumulator pressure Pa detected by the accumulator pressure sensor 51 at a predetermined cycle, and when the accumulator pressure Pa falls below a preset minimum set pressure. The motor 32 is driven to pressurize the hydraulic fluid by the pump 31, and control is performed so that the accumulator pressure Pa is always maintained within the set pressure range.

  The microcomputer 100a performs hydraulic pressure control of the wheel cylinders 82FR, 82FL, 82RR, 82RL by energizing the hydraulic pressure control valves 50FR, 50FL, 50RR, 50RL based on the operation amount of the brake pedal 10. In this case, the microcomputer 100a sets the target for each of the wheel cylinders 82FR, 82FL, 82RR, and 82RL based on the operation amount of the brake pedal (for example, the pedal stroke Sp that represents the depression amount or the master cylinder pressure Pm that represents the depression force). The hydraulic pressure is set, and the linear control valves 44FR, 44FL, 44RR, 44RL for pressure increase by feedback control so that the wheel cylinder pressure Pw detected by the wheel cylinder pressure sensors 53FR, 53FL, 53RR, 53RL becomes equal to the target hydraulic pressure. And the drive current to the pressure-reducing linear control valves 45FR, 45FL, 45RR, 45RL.

  On the other hand, the rapid activation differs from the normal activation in that the simulator cut valve 72 is not opened simultaneously with the activation. Therefore, when the rapid is started, the master cut valves 46 and 47 are closed, the operation of the power hydraulic pressure generator 30 is started, and the hydraulic pressure control by the hydraulic pressure control valve 50 is started. . Further, at the time of rapid start-up, as will be described later, when the operation-related value that changes in conjunction with the operation of the brake pedal 10 exceeds a preset reference range, the simulator cut valve 72 or the master cut valve 46, 47 is opened to a predetermined opening, and the hydraulic fluid in the master cylinder 20 is allowed to flow out to control the pedal depression rigidity. Hereinafter, pedal depression rigidity control which is this difference will be described.

<Embodiment 1 of pedal depression rigidity control>
FIG. 2 shows a pedal depression rigidity control routine executed by the brake ECU 100 according to the first embodiment. In step S11, the brake ECU 100 determines whether or not the brake ECU 100 (the microcomputer 100a) is in a sleep state and the pedal switch 102 is turned on. This process is performed by the power supply circuit 100c, and is repeated at a predetermined short cycle until the pedal switch signal Sw1 input from the pedal switch 102 is turned on when the brake ECU 100 is in the operation stop state. When the pedal switch signal Sw1 input to the power supply circuit 100c is turned on (S11: Yes), the power supply circuit 100c supplies battery power to the microcomputer 100a and the drive circuit 100b. Thereby, the microcomputer 100a is activated. In this case, the microcomputer 100a confirms that the pedal switch signal Sw1 is turned on, and performs rapid activation in step S12. That is, rapid braking control is started. By this rapid activation, the master cut valves 46 and 47 are closed, the operation of the power hydraulic pressure generator 30 is started, and the wheel cylinder pressure control by the hydraulic pressure control valve 50 is started. At this time, the simulator cut valve 72 is kept closed.

  Subsequently, in step S13, the microcomputer 100a determines whether or not a pedal stiffness control permission condition is satisfied. In this embodiment, the pedal stiffness control permission condition is set such that the master cylinder pressure Pm detected by the master cylinder pressure sensor 52 exceeds the threshold value Pmref. In other words, the pedal rigidity control permission condition is established when the pedaling force on the brake pedal 10 exceeds a predetermined value.

  In step S13, the microcomputer 100a reads the master cylinder pressure Pm detected by the master cylinder pressure sensor 52. If the master cylinder pressure Pm does not exceed the threshold value Pmref, the pedal rigidity control permission condition is not satisfied. Determination is made and the process proceeds to step S15. In step S15, the microcomputer 100a determines whether or not the pedal switch signal Sw1 is turned off. If the pedal switch signal Sw1 is not turned off, the microcomputer 100a returns the process to step S13.

  Therefore, after the rapid activation, while the brake pedal 10 is depressed, the determination as to whether or not the pedal stiffness control permission condition is satisfied is repeated. When the master cylinder pressure Pm exceeds the threshold value Pmref, the pedal stiffness control permission condition is satisfied, and the microcomputer 100a advances the process to step S14.

  At the time of rapid start-up, the master cylinder 20 and the wheel cylinder 82 are shut off by the master cut valves 46 and 47, and the simulator cut valve 72 is maintained in the closed state, so that the amount of hydraulic fluid that can be delivered from the master cylinder 20 Becomes very small and the hydraulic rigidity just below the brake pedal increases. There is no problem when the pedal operation amount is small, but when the pedal operation amount is large, the pedal stroke is reduced with respect to the pedaling force applied to the brake pedal 10, and the driver feels uncomfortable. That is, a hard brake operation feeling (a so-called board feeling) is felt. Therefore, in the present embodiment, when the brake pedal operation amount increases, the hydraulic rigidity just below the brake pedal 10 is lowered as described below.

  When the pedal stiffness control permission condition is satisfied (S13: Yes), the microcomputer 100a outputs a duty signal to the simulator cut valve 72 to open the simulator cut valve 72 in step S14. The simulator cut valve 72 employs an electromagnetic valve that can adjust the opening degree of the valve body by changing the duty ratio for energizing the solenoid. The simulator cut valve 72 is controlled so as to be opened by continuous energization to the solenoid (energization with a duty ratio of 100%) at the time of normal activation. In this step S14, the duty ratio is smaller than that at the time of normal activation. The solenoid is energized at (<100%). Therefore, in step S14, the simulator cut valve 72 is opened to an opening that is narrower than the opening at the time of normal activation.

  As a result, hydraulic fluid flows from the master cylinder 20 to the stroke simulator 71, and an increase in hydraulic rigidity just below the brake pedal 10 is suppressed.

  The microcomputer 100a repeats the processes of steps S13 to S15 until the pedal switch signal Sw1 is turned off. When the pedal switch signal Sw1 is turned off, the pedal depression rigidity control routine is terminated. If the pedal switch signal Sw1 is turned off after the rapid activation (S15: Yes), the microcomputer 100a switches to the normal activation braking control. Therefore, the simulator cut valve 72 is energized to the solenoid at a duty ratio of 100%.

  According to the pedal depression rigidity control according to the first embodiment described above, the pedal depression rigidity control (S14) is not performed because the driver does not feel the feeling of stepping on the pedal when the depression force on the brake pedal 10 is small. When the cylinder pressure Pm exceeds the threshold value Pmref, the working fluid is caused to flow from the master cylinder 20 to the stroke simulator 71. Thereby, an appropriate pedal stroke can be obtained with respect to the depression force applied to the brake pedal 10, and the feeling of board depression given to the driver can be reduced. In this case, since the opening degree of the simulator cut valve 72 is reduced as compared with the normal activation, it is difficult to give the driver the impression that the brake pedal 10 has entered. Furthermore, in this Embodiment 1, since it can implement even without providing the pedal stroke sensor 101, a system structure can be simplified.

<Embodiment 2 of pedal depression rigidity control>
FIG. 3 shows a pedal depression rigidity control routine executed by the brake ECU 100 according to the second embodiment. The pedal depression rigidity control routine of the second embodiment performs step S24 instead of step S14 of the pedal depression rigidity control routine of the first embodiment, and other processes are the same as those of the first embodiment. For the common processes, the same step symbols as those in the first embodiment are attached to the drawings, and the description thereof is omitted.

  When the pedal stiffness control permission condition is satisfied in step S13, the microcomputer 100a outputs a duty signal to the master cut valves 46 and 47 to open the master cut valves 46 and 47 in the subsequent step S24. As the master cut valves 46 and 47, electromagnetic valves that can adjust the opening degree of the valve body by changing the duty ratio of energizing the solenoid are employed. The master cut valves 46 and 47 are maintained in the valve open state when the brake ECU 100 is not in operation (not activated) and are not energized to the solenoid, and the solenoid is continuously energized by the activation of the brake ECU 100 (duty ratio 100%). Is closed by electromagnetic force. In this step S24, by reducing the energization amount to the solenoid, that is, by reducing the duty ratio energizing the solenoid, the electromagnetic force is lowered and the valve element is moved in the valve opening direction by a spring (not shown). . Therefore, the master cut valves 46 and 47 are opened to an opening that is throttled compared to the opening (fully opened) when the brake ECU 100 is not in operation.

  As a result, hydraulic fluid flows from the master cylinder 20 to the front wheel cylinders 82FR and 82FL, and an increase in hydraulic rigidity just below the brake pedal 10 is suppressed.

  According to the pedal depression rigidity control according to the second embodiment described above, the pedal depression rigidity control (S24) is not performed because the driver does not feel the feeling of stepping on the pedal when the depression force on the brake pedal 10 is small. When the cylinder pressure Pm exceeds the threshold value Pmref, the working fluid is caused to flow from the master cylinder 20 to the front wheel cylinders 82FR and 82FL. Thereby, an appropriate pedal stroke can be obtained with respect to the depression force applied to the brake pedal 10, and the feeling of board depression given to the driver can be reduced. In this case, since the opening degree of the master cut valves 46 and 47 is reduced, the flow rate of the hydraulic fluid flowing from the master cylinder 20 to the front wheel cylinders 82FR and 82FL can be made appropriate, and the brake pedal 10 enters the driver. It is hard to give an impression. Moreover, in this Embodiment 2, since it can implement even without providing the pedal stroke sensor 101, a system structure can be simplified.

  Further, at the time of rapid start-up that is started by stepping on the brake pedal 10, there may be a case where the hydraulic pressure (accumulator pressure) output from the power hydraulic pressure generator 30 immediately after startup is lower than the set pressure range. In such a case, in the second embodiment, the wheel cylinder pressure can be quickly increased by supplying hydraulic fluid from the master cylinder 20 to the front wheel cylinders 82FR and 82FL. Therefore, the pedal depression rigidity control routine of the second embodiment can be particularly effectively used from the viewpoint of fail-safe.

<Modification 1 of pedal rigidity control permission condition>
In the first and second embodiments of pedal depression rigidity control described above, the pedal rigidity control permission condition is that the master cylinder pressure Pm exceeds the threshold value Pmref, but the pedal rigidity control permission condition is not limited to this. For example, the pedal stiffness control permission condition may be set such that the depression amount of the brake pedal 10 exceeds a predetermined value. In this case, the microcomputer 100a reads the pedal stroke Sp detected by the pedal stroke sensor 101 in step S13, and determines that the pedal stiffness control permission condition is satisfied when the pedal stroke Sp exceeds the threshold value Spref. (S13: Yes).

<Modification 2 of pedal rigidity control permission condition>
Further, the pedal stiffness control permission condition may be set such that at least one of the depression force and the depression amount of the brake pedal 10 exceeds a predetermined value. In this case, the microcomputer 100a reads the master cylinder pressure Pm detected by the master cylinder pressure sensor 52 and the pedal stroke Sp detected by the pedal stroke sensor 101 in step S13, and the master cylinder pressure Pm exceeds the threshold value Pmref. Or when the pedal stroke Sp exceeds the threshold value Spref, it may be determined that the pedal stiffness control permission condition is satisfied (S13: Yes).

<Modification 3 of pedal rigidity control permission condition>
Further, based on the relationship between the depression amount and the depression force of the brake pedal 10, it may be set as a pedal rigidity control permission condition that the depression force with respect to the depression amount exceeds a predetermined value. For example, as shown by a solid line in FIG. 4, the microcomputer 100a stores a reference map (reference data) representing the relationship between the average pedal stroke Sp and the master cylinder pressure Pmref in the normal startup braking control. The degree of difference between the relationship between the pedal stroke Sp and the master cylinder pressure Pm detected after the rapid activation is started and the relationship in the reference map is calculated. The reference map has a characteristic that the master cylinder pressure Pmref increases as the pedal stroke Sp increases.

  In this case, in step S13, the microcomputer 100a reads the pedal stroke Sp detected by the pedal stroke sensor 101 and the master cylinder pressure Pm detected by the master cylinder pressure sensor 52 and displays them on the reference map for the detected pedal stroke Sp. The deviation e between the master cylinder pressure Pmref and the detected master cylinder pressure Pm is calculated. When the rapid activation is performed, the simulator cut valve 72 is closed, so that the actual master cylinder pressure Pm becomes higher than the master cylinder pressure Pmref (referred to as reference master cylinder pressure Pmref) in the reference map. Therefore, a value obtained by subtracting the reference master cylinder pressure Pmref from the master cylinder pressure Pm is a deviation e (Pm−Pmref).

  In the case of rapid activation, the characteristics shown by the broken line in FIG. 4 are shown. For this reason, when rapid activation is performed, the brake operation feeling is harder than when normal activation is performed, and the deviation e of the master cylinder pressure increases as the pedal stroke Sp increases. Therefore, in the third modification, the microcomputer 100a uses the deviation e as an index indicating the degree of difference, and when the deviation e exceeds the threshold eref (e> eref) in step S13, the pedal stiffness control permission condition is satisfied. It is determined that it has been established.

  According to this, since it is determined that the pedal rigidity control permission condition is satisfied using the deviation e of the master cylinder pressure with respect to the pedal stroke Sp, it is possible to accurately determine the degree of difference from the characteristic at the time of normal activation. As a result, pedal depression rigidity control (S14, S24) can be started at an appropriate timing. For this reason, the start of the pedal depression rigidity control is prevented from being delayed or conversely too early, and stable pedal depression rigidity control can be performed.

  In the third modification, the pedal rigidity control permission condition is set based on the deviation of the depression force with respect to the depression amount from the relationship between the depression amount of the brake pedal 10 and the depression force. The pedal stiffness control permission condition may be set based on the deviation of the depression amount with respect to the force. In this case, the microcomputer 100a determines that the pedal stroke deviation e ′ with respect to the detected master cylinder pressure Pm (a value obtained by subtracting the detected pedal stroke Sp from the pedal stroke Spref with respect to the master cylinder pressure Pm on the reference map (Spref−Sp )) Is calculated, and this deviation e ′ is used as an index representing the degree of difference. In step S13, it is determined that the pedal stiffness control permission condition is satisfied when the deviation e ′ exceeds the threshold value eref ′.

<Modification 1 of Duty Ratio Control>
In the first and second embodiments of the pedal depression rigidity control described above, when the pedal depression rigidity control is performed in steps S14 and S24, the simulator cut valve 72 or the master cut valves 46 and 47 are set at a preset duty ratio. The solenoid is energized, but the duty ratio may be varied. FIG. 5 is a flowchart showing a process performed in place of the processes of steps S13 to S15 in the pedal depression rigidity control routine (FIG. 2) of the first embodiment described above as a first modification of the duty ratio control. In this process, the process of step S34 is incorporated instead of step S14. In addition, about the process of step S11, S12, it is the same as embodiment.

In step S13, the microcomputer 100a determines whether the pedal rigidity control permission condition is satisfied. In determining whether the pedal rigidity control permission condition is satisfied, as described above, it may be determined that the master cylinder pressure Pm exceeds the threshold value Pmref (Pm> Pmref), or a modification example of the pedal rigidity control permission condition The determination described in 1, 2, 3 may be performed. When the pedal stiffness control permission condition is satisfied (S13: Yes), the microcomputer 100a reads the master cylinder pressure Pm detected by the master cylinder pressure sensor 52 in the subsequent step S34, and based on the master cylinder pressure Pm, the simulator cut valve The duty ratio d of 72 is set by the following equation (1).
d = d + k × f (Pm) (1)

  Here, k is a preset coefficient. For example, f (Pm) is a function (for example, a linear function) that calculates a value proportional to the master cylinder pressure Pm. Therefore, f (Pm) takes a larger value as the master cylinder pressure Pm increases. The initial value of the duty ratio d is set to an arbitrary value (for example, zero). When the duty ratio d is set, the microcomputer 100a energizes the solenoid of the simulator cut valve 72 at the set duty ratio. Thereby, the simulator cut valve 72 opens at an opening degree corresponding to the duty ratio d.

  Steps S13, S34, and S15 are repeated until the pedal switch signal Sw1 is turned off. Therefore, k × f (Pm) represents the increase amount of the duty ratio in one calculation cycle. Thereby, the duty ratio d gradually increases from the initial value. Therefore, the stroke simulator 71 can be made to function gradually, and a sudden change in the brake operation feeling can be prevented. Further, the increasing rate of the duty ratio d increases as the master cylinder pressure Pm increases. Therefore, the larger the master cylinder pressure Pm, the faster the function of the stroke simulator 71 can be obtained. As a result, it is possible to create an appropriate pedal reaction force according to the pedal depression force of the driver, and to further improve the pedal operation feeling.

<Modification 2 of Duty Ratio Control>
FIG. 6 is a flowchart showing a process performed in place of the processes of steps S13 to S15 in the pedal depression rigidity control routine (FIG. 2) of the first embodiment described above as a second modification of the duty ratio control. In this process, the process of step S44 is incorporated instead of step S14.

In step S13, the microcomputer 100a determines whether the pedal rigidity control permission condition is satisfied. The determination in step S13 is as described in the first modification of the duty ratio control. When the pedal stiffness control permission condition is satisfied (S13: Yes), the microcomputer 100a reads the pedal stroke Sp detected by the pedal stroke sensor 101 in the following step S44, and based on the pedal stroke Sp, the duty of the simulator cut valve 72 is read. The ratio d is set by the following equation (2).
d = d + k × f (Sp) (2)

  Here, k is a preset coefficient. For example, f (Sp) is a function (for example, a linear function) that calculates a value proportional to the pedal stroke Sp. Therefore, f (Sp) takes a larger value as the pedal stroke Sp is larger. The initial value of the duty ratio d is set to an arbitrary value (for example, zero). When the duty ratio d is set, the microcomputer 100a energizes the solenoid of the simulator cut valve 72 at the set duty ratio. Thereby, the simulator cut valve 72 opens at an opening degree corresponding to the duty ratio d.

  Steps S13, S44, and S15 are repeated until the pedal switch signal Sw1 is turned off. Therefore, k × f (Sp) represents an increase amount of the duty ratio in one calculation cycle. Thereby, the duty ratio d gradually increases from the initial value. Therefore, the stroke simulator 71 can be made to function gradually, and a sudden change in the brake operation feeling can be prevented. Further, the increasing speed of the duty ratio d increases as the pedal stroke Sp increases. Therefore, the larger the pedal stroke Sp, the faster the function of the stroke simulator 71 can be obtained. As a result, it is possible to create an appropriate pedal reaction force according to the pedal depression force of the driver, and to further improve the pedal operation feeling.

  In the first and second modifications of the duty ratio control, when the duty ratio d of the simulator cut valve 72 reaches 100%, the duty ratio d may be maintained at 100% thereafter. Therefore, it is possible to smoothly shift from the rapid starting braking control to the normal starting braking control.

<Modification 3 of Duty Ratio Control>
In the first and second modifications of the duty ratio control described above, the duty ratio d of the simulator cut valve 72 is gradually increased. In this third modification, the depression amount and the depression amount of the brake pedal 10 are set. The duty ratio d of the simulator cut valve 72 is controlled so that the relationship with the force (that is, the relationship between the pedal stroke and the master cylinder pressure) does not change from the normal startup braking control. FIG. 7 is a flowchart showing a process performed in place of the processes of steps S13 to S15 in the pedal depression rigidity control routine (FIG. 2) of the first embodiment described above as the third modification of the duty ratio control. In this process, steps S141 and S142 are incorporated instead of step S14.

  In step S13, the microcomputer 100a determines whether the pedal rigidity control permission condition is satisfied. The determination in step S13 is as described in the first modification of the duty ratio control. When the pedal stiffness control permission condition is satisfied (S13: Yes), the microcomputer 100a determines the pedal stroke Sp detected by the pedal stroke sensor 101 and the master cylinder pressure Pm detected by the master cylinder pressure sensor 52 in the subsequent step S141. The deviation e between the master cylinder pressure Pmref on the reference map for the read and detected pedal stroke Sp and the detected master cylinder pressure Pm is calculated. This reference map is a map indicated by a solid line in FIG. 4 described in Modification 3 of the pedal rigidity control permission condition.

Subsequently, in step S142, the microcomputer 100a sets the duty ratio d of the simulator cut valve 72 by the following equation (3) based on the deviation e.
d = f (e) (3)

  f (e) is a function for setting the duty ratio so that the deviation e becomes smaller using the deviation e as a parameter, and sets a duty ratio that increases as the deviation e increases. For example, it may be a linear function that sets a duty ratio that is proportional to the deviation e, or may be a function that sets the duty ratio in feedback control using the deviation e, for example, PID control. .

  When the duty ratio d is set, the microcomputer 100a energizes the solenoid of the simulator cut valve 72 with the set duty ratio d. Thereby, the simulator cut valve 72 opens at an opening degree corresponding to the duty ratio d.

  The processes in steps S13, S141, S142, and S15 are repeated until the pedal switch signal Sw1 is turned off. Thereby, the opening degree of the simulator cut valve 72 is adjusted so that the deviation e is reduced. Therefore, the relationship between the pedal stroke and the master cylinder pressure is not much different from the relationship in the normal activation braking control even when the rapid activation is performed, and an increase in hydraulic rigidity just below the brake pedal 10 is suppressed. For this reason, an appropriate pedal stroke can be obtained with respect to the depression force applied to the brake pedal 10, and the feeling of the stepping on the board given to the driver can be reduced.

<Modification 4 of Duty Ratio Control>
In the above-described modification 3 of the duty ratio control, by controlling the duty ratio of the simulator cut valve 72, the feeling of the step on the plate given to the driver at the time of the rapid start-up is alleviated. The target for controlling the duty ratio is the master cut valves 46 and 47 instead of the simulator cut valve 72. FIG. 8 is a flowchart showing a process performed in place of the processes of steps S13, S24, and S15 in the pedal depression rigidity control routine of the second embodiment described above as the fourth modification of the duty ratio control. In this process, steps S241 and S242 are incorporated in place of step S24. The process of step S241 is the same as the process of step S141 in modification 3 of the duty ratio control.

In step S241, the microcomputer 100a calculates a deviation e between the master cylinder pressure Pmref on the reference map with respect to the detected pedal stroke Sp and the detected master cylinder pressure Pm. Subsequently, in step S242, the microcomputer 100a sets the duty ratio dm of the master cut valves 46 and 47 by the following equation (4) based on the deviation e.
dm = f (e) (4)

  f (e) is a function for setting the duty ratio so that the deviation e becomes smaller using the deviation e as a parameter, and sets a duty ratio that increases as the deviation e increases. For example, it may be a linear function that sets a duty ratio that is proportional to the deviation e, or may be a function that sets the duty ratio in feedback control using the deviation e, for example, PID control. . Since the master cut valves 46 and 47 are normally open solenoid valves, the opening degree increases as the energization amount decreases. For this reason, the duty ratio dm represents the off-duty ratio, that is, the ratio of the off period in one on / off cycle of energization. Therefore, the larger the deviation e, the larger the off-duty ratio dm and the larger the opening of the master cut valves 46, 47.

  When the duty ratio dm is set, the microcomputer 100a energizes the solenoids of the master cut valves 46 and 47 with the set duty ratio dm. Thereby, the master cut valves 46 and 47 are opened at an opening degree corresponding to the duty ratio dm.

  Steps S13, S241, S242, and S15 are repeated until the pedal switch signal Sw1 is turned off. Thereby, the opening degree of the master cut valves 46 and 47 is adjusted so that the deviation e is reduced. Therefore, the relationship between the pedal stroke and the master cylinder pressure is not much different from the relationship in the normal activation braking control even when the rapid activation is performed, and an increase in hydraulic rigidity just below the brake pedal 10 is suppressed. For this reason, an appropriate pedal stroke can be obtained with respect to the depression force applied to the brake pedal 10, and the feeling of the stepping on the board given to the driver can be reduced.

  Further, according to the modification 4 of the duty ratio control, as described in the second embodiment of the pedal depression rigidity control, the hydraulic pressure (accumulator pressure) output from the power hydraulic pressure generator 30 immediately after the rapid start-up is within the set pressure range. Even when the pressure is lower than that, the hydraulic fluid is replenished from the master cylinder 20 to the front wheel cylinders 82FR and 82FL, so that the wheel cylinder pressure can be increased quickly. Therefore, it can be used particularly effectively from the viewpoint of fail-safe.

  In the third and fourth modifications of the duty ratio control, the master on the reference map for the pedal stroke Sp is maintained so that the relationship between the depression amount and the depression force of the brake pedal 10 does not change even at the time of rapid activation. The deviation e between the cylinder pressure Pmref and the detected master cylinder pressure Pm is used to control the duty ratio of the simulator cut valve 72 or the master cut valves 46, 47. Instead, the deviation of the depression amount with respect to the depression force The duty ratio may be controlled based on the above. In this case, the microcomputer 100a determines that the pedal stroke deviation e ′ with respect to the detected master cylinder pressure Pm (a value obtained by subtracting the detected pedal stroke Sp from the pedal stroke Spref with respect to the master cylinder pressure Pm on the reference map (Spref−Sp )) And the duty ratio of the simulator cut valve 72 or the master cut valves 46 and 47 may be controlled using the deviation e ′ so that the deviation e ′ is reduced.

<Embodiment 3 of pedal depression rigidity control>
In the first and second embodiments of the pedal depression rigidity control described above and the modifications thereof, it is determined in step S13 that the pedal rigidity control permission condition is satisfied, and the pedal rigidity control permission condition is satisfied (S13: Yes). ), The simulator cut valve 72 or the master cut valves 46 and 47 are opened (half-open) to reduce the hydraulic rigidity just below the brake pedal 10, but in the third embodiment, In the embodiment and the modification, the process of step S13 is omitted. That is, all of step S13 in the flowcharts shown in FIGS. 2 to 3 and FIGS. 5 to 8 is deleted, and pedal depression rigidity control is always performed without determining whether the pedal rigidity control permission condition is satisfied. According to the third embodiment, after the rapid activation, the simulator cut valve 72 or the master cut valves 46 and 47 are opened at an opening degree adjusted by the duty ratio (an opening degree that is throttled rather than fully opened). The feeling of entering the brake pedal 10 and the feeling of stepping on the plate can be suppressed.

  The vehicle brake control device according to this embodiment and the modification has been described above, but the present invention is not limited to the above-described embodiment and modification, and various modifications can be made without departing from the object of the present invention. It is.

  For example, in the present embodiment, four wheel cylinder pressures are applied to a brake control device that is independently controlled by a linear control valve provided for each wheel. The present invention can also be applied to a brake control device that is controlled by a linear control valve (for example, a pressure-increasing linear control valve and a pressure-decreasing linear control valve).

  In the present embodiment, the master cylinder 20 communicates only with the wheel cylinder on the front wheel side via the master cut valve. For example, the master cylinder 20 is connected to the four wheel wheel cylinder via the master cut valve. The structure which communicates may be sufficient.

  In the present embodiment, when the pedal depression rigidity control is performed, the two master cut valves 46 and 47 are simultaneously opened, but only one of the master cut valves 46 (47) is opened. It may be.

  Further, in the present embodiment, it is configured to normally start when either the ignition switch or the courtesy switch is turned on, but it may be configured to be normally started only by the ignition switch.

  DESCRIPTION OF SYMBOLS 10 ... Brake pedal, 20 ... Master cylinder, 21, 22 ... Pressurizing chamber, 23, 24 ... Master passage, 24 ... Master flow path, 30 ... Power hydraulic pressure generator, 31 ... Pump, 32 ... Motor, 33 ... Accumulator , 40 ... brake actuator, 42 ... return passage, 43FR, 43FL, 43RR, 43RL ... individual passage, 44FR, 44FL, 44RR, 44RL ... linear control valve for pressure increase, 45FR, 45FL, 45RR, 45RL ... linear control valve for pressure reduction, 46, 47 ... master cut valve, 50FR, 50FL, 50RR, 50RL ... hydraulic pressure control valve, 51 ... accumulator pressure sensor, 52R, 52L ... master cylinder pressure sensor, 53FR, 53FL, 53RR, 53RL ... wheel cylinder pressure sensor, 60 ... reservoir, 70 ... stroke simulator device, DESCRIPTION OF SYMBOLS 1 ... Stroke simulator, 72 ... Simulator cut valve, 80FR, 80FL, 80RR, 80RL ... Disc brake unit, 81FR, 81FL, 81RR, 81RL ... Brake disc, 82FR, 82FL, 82RR, 82RL ... Wheel cylinder, 100 ... Brake ECU, DESCRIPTION OF SYMBOLS 100a ... Microcomputer, 100b ... Drive circuit, 100c ... Power supply circuit, 101 ... Pedal stroke sensor, 102 ... Pedal switch, 103 ... Courtesy switch, 104 ... Ignition switch

Claims (9)

A plurality of wheel cylinders that are provided on each of the plurality of wheels and receive the hydraulic pressure of the hydraulic fluid to apply braking force to the wheels;
A master cylinder that generates hydraulic pressure by operating force input to the brake pedal;
A power hydraulic pressure source that generates hydraulic pressure regardless of the operation of the brake pedal;
A stroke simulator connected to the master cylinder, allowing a flow of hydraulic fluid sent from the master cylinder and generating a reaction force according to a brake operation amount;
Pedal operation detecting means for detecting the brake pedal operation;
With the plurality of wheel cylinders disconnected from the master cylinder, hydraulic pressure control of the wheel cylinder is performed so that a target hydraulic pressure is applied to the wheel cylinder from the power hydraulic pressure source while operating the stroke simulator. An electronic control unit;
Rapid starting means for starting the electronic control device triggered by a brake pedal operation,
Brake control of a vehicle in which the master cylinder and at least a part of the plurality of wheel cylinders are maintained in communication with each other while the function of the stroke simulator is stopped when the electronic control unit is not activated In the device
The electronic control device
When activated by the rapid activation means, the rapid operation of starting the hydraulic pressure control of the wheel cylinder by cutting off the communication between the wheel cylinder and the master cylinder with the function of the stroke simulator stopped Control means;
After the operation start of the rapid starting control means, when the operation related value that changes in conjunction with the operation of the brake pedal exceeds a preset reference range, the wheel cylinder and the master cylinder are communicated, Alternatively, a brake control device for a vehicle, comprising: pedal depression rigidity control means for making the stroke simulator operable. The wheel cylinder and the master cylinder are connected via a normally open valve,
The stroke simulator and the master cylinder are connected via a normally closed valve,
The pedal depression rigidity control means opens the normally open valve to a state in which the opening degree is reduced by energization control of the normally open valve to communicate the wheel cylinder and the master cylinder, or the normally closed valve 2. The vehicle brake control device according to claim 1, wherein the normally closed valve is opened to a state in which the opening degree is reduced by the energization control of the vehicle to make the stroke simulator operable. 3.   The pedal depression rigidity control means gradually increases the opening degree of the normally closed valve by energization control of the normally closed valve. The larger the depression amount or the depression force of the brake pedal, the larger the opening degree. The vehicle brake control device according to claim 2, wherein the increasing speed is increased. The pedal depression rigidity control means includes:
Storage means for storing reference data representing a relationship between a depression amount and a depression force of the brake pedal set in advance;
Actual data acquisition means for acquiring actual data representing the actual depression amount and depression force of the brake pedal,
The normally open valve is set such that the degree of difference between the relationship between the depression amount and the depression force of the brake pedal represented by the actual data and the relationship between the depression amount and the depression force of the brake pedal represented by the reference data is reduced. The vehicle brake control device according to claim 2, wherein the opening degree of the normally closed valve is controlled.   The vehicle brake control device according to claim 4, wherein the degree of difference is represented by a deviation between a depression force represented by the reference data and an actual depression force with respect to an actual depression amount of the brake pedal.   6. The vehicle brake control device according to claim 1, wherein the operation-related value that changes in conjunction with the operation of the brake pedal is a depression amount of the brake pedal.   The vehicle brake control device according to any one of claims 1 to 5, wherein the operation-related value that changes in conjunction with the operation of the brake pedal is a depression force of the brake pedal.   The operation-related value that changes in conjunction with the operation of the brake pedal is a preset relationship between the depression amount and the depression force of the brake pedal and an actual relationship between the depression amount and the depression force of the brake pedal. The vehicle brake control device according to any one of claims 1 to 5, wherein the vehicle brake control device is a value representing a degree of difference. A plurality of wheel cylinders that are provided on each of the plurality of wheels and receive the hydraulic pressure of the hydraulic fluid to apply braking force to the wheels;
A master cylinder that generates hydraulic pressure by operating force input to the brake pedal;
A power hydraulic pressure source that generates hydraulic pressure regardless of the operation of the brake pedal;
A stroke simulator connected to the master cylinder, allowing a flow of hydraulic fluid flowing out of the master cylinder and generating a reaction force according to a brake operation amount;
Pedal operation detecting means for detecting the brake pedal operation;
With the plurality of wheel cylinders disconnected from the master cylinder, hydraulic pressure control of the wheel cylinder is performed so that a target hydraulic pressure is applied to the wheel cylinder from the power hydraulic pressure source while operating the stroke simulator. An electronic control unit;
Rapid starting means for starting the electronic control device triggered by a brake pedal operation,
Brake control of a vehicle in which the master cylinder and at least a part of the plurality of wheel cylinders are maintained in communication with each other while the function of the stroke simulator is stopped when the electronic control unit is not activated In the device
The electronic control device
When activated by the rapid activation means, the rapid operation of starting the hydraulic pressure control of the wheel cylinder by cutting off the communication between the wheel cylinder and the master cylinder with the function of the stroke simulator stopped Control means;
After the operation of the rapid starting control means is started, the wheel cylinder and the master cylinder are communicated with a reduced opening, or the stroke simulator and the master cylinder are communicated with a reduced opening. A brake control device for a vehicle, comprising: pedal depression rigidity control means.

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