KR20230133139A - Electronic parking brake - Google Patents

Abstract

Disclosed is an electronic parking brake. According to one aspect of the present invention, the provided electronic parking brake comprises: a pair of pressurizing units provided in a caliper housing to convert rotational movement into linear movement to pressurize a brake pad; a driving unit which receives a power supply from the exterior and generates a power; a differential gear unit connected to the driving unit and provided so that a first shaft and a second shaft arranged in a straight line rotate in the same direction by a rotational force of the driving unit; a pair of power transmitting units respectively connected to the first shaft and the second shaft; and a reducing gear unit which is respectively connected to the pair of power transmitting units and transmits the rotational force to the pair of pressurizing units.

Description

Electronic parking brake

The present invention relates to an electronic parking brake, and more specifically, to an electronic parking brake in which a caliper brake having two pistons can implement a parking function by applying a uniform load to the two pistons by the operation of one motor. will be.

In general, a brake device is a device for stopping a vehicle from moving during braking or parking, and serves to prevent the wheels of the vehicle from rotating.

Recently, an electronic parking brake (EPB) system that electronically controls the operation of the parking brake has been widely used. It is mounted on a regular caliper brake and performs the function of a parking brake. There are three types of electronic caliper brakes: cable puller type, motor-on-caliper (MOC) type, and hydraulic parking brake type.

Looking at patent document Korea Patent Publication No. 10-2011-0072877 (2011.06.29.), the document relates to a MOC type electronic parking brake, in which a motor that generates power is connected to an actuator, and the power generated from the motor is connected to the actuator. A structure is disclosed that uses multiple gear devices to reduce speed while increasing torque to press the brake pad with a piston to perform a braking operation.

Meanwhile, vehicles such as large trucks that require large braking force are provided with a plurality of pistons (usually two pistons) and are used to perform braking operations.

However, when a plurality of pistons are provided and the driving force is transmitted from a single actuator, the braking force required for vehicles such as large trucks cannot be provided, which poses a safety problem. In addition, there is a problem in that load is unevenly transmitted to a plurality of pistons depending on the uneven initial piston position, and uneven wear of brake pads, uneven wear of gears, and motor overload occur due to asymmetry. As a result, there is a problem in that parking performance deteriorates.

To solve this problem, the same number of actuators as the pistons were provided to transmit power to each of the plurality of pistons, but there is a problem in that the weight and cost increase, and the installation space is narrow, making application difficult.

Korean Patent Publication No. 10-2011-0072877 (2011.06.29)

The electronic parking brake according to an embodiment of the present invention applies a uniform load to a plurality of pistons through one motor and implements a parking function.

According to one aspect of the present invention, a pair of pressing parts provided in the caliper housing to convert rotational motion into linear motion to pressurize the brake pad; A driving unit that receives power from the outside and generates power; A differential gear unit connected to the drive unit and provided so that a first shaft and a second shaft arranged in a straight line rotate in the same direction by the rotational force of the drive unit; a pair of power transmission units respectively connected to the first shaft and the second shaft; And an electronic parking brake including a reduction gear unit respectively connected to the pair of power transmission units and transmitting rotational force to the pair of pressing units.

In addition, the differential gear unit includes a driving gear coupled to the rotation shaft of the driving unit; A ring gear having a ring shape with a hollow center, the outer surface of which rotates in engagement with the driving gear; a pair of first gears installed to face each other on the inner surface of the ring gear and rotating together with the ring gear; The first shaft disposed on one side of the ring gear toward the hollow; the second shaft disposed on the other side of the ring gear toward the hollow; and a pair of second gears installed to face each other on the first shaft and the second shaft so as to be vertically engaged with the pair of first gears.

In addition, the pair of power transmission units includes a worm gear installed on the first shaft and the second shaft; and a worm wheel gear engaged with and rotating with the worm gear.

In addition, the pair of reduction gear units includes a reduction sun gear coupled to the center of the worm wheel gear and rotating together with the rotation of the worm wheel gear; a plurality of reduction planetary gears meshed on the outside of the reduction sun gear; a reduction ring gear made of internal gears to accommodate the plurality of reduction planetary gears; and a reduction carrier that rotatably supports the plurality of reduction planet gears and is installed to rotate coaxially with the reduction sun gear to output rotational power.

Additionally, the pair of reduction gear units may each be provided to have a multi-stage planetary gear assembly structure.

In addition, the pair of pressing parts includes a piston slidably inserted into the cylinder part of the caliper housing; and a spindle that rotates within the cylinder unit by receiving driving force from the reduction gear unit, and is connected to the spindle and moves forward or backward by forward and reverse rotation of the spindle, and is provided on the inside of the piston to press or release the piston. It may include a power conversion unit having a nut.

The electronic parking brake according to an embodiment of the present invention has the effect of implementing a stable parking function by imparting a uniform load by transmitting uniform power to a pair of pressing parts through a differential gear unit. In other words, it is possible to provide the braking force required for a vehicle that requires a large braking force by applying a uniform load to a plurality of pistons through one motor. Accordingly, it has the effect of significantly reducing the volume and manufacturing cost of the electronic parking brake compared to the prior art.

The present invention will be explained in detail with the drawings below, but since these drawings show preferred embodiments of the present invention, the technical idea of the present invention should not be construed as limited to the drawings.
1 is a perspective view showing an electronic parking brake according to an embodiment of the present invention.
Figure 2 is a rear perspective view showing an electronic parking brake according to an embodiment of the present invention.
Figure 3 is a side cross-sectional view showing an electronic parking brake according to an embodiment of the present invention.
Figure 4 is a partial perspective view showing an electronic parking brake according to an embodiment of the present invention.
Figure 5 is an exploded perspective view showing a pair of pressing parts provided in an electronic parking brake according to an embodiment of the present invention.
Figure 6 is an exploded perspective view showing the combined state of the driving unit, differential gear unit, and power transmission unit provided in the electronic parking brake according to an embodiment of the present invention.
Figure 7 is an assembled perspective view of Figure 6.
Figure 8 is an exploded perspective view showing the coupled state of the power transmission unit and the reduction gear unit provided in the electronic parking brake according to an embodiment of the present invention.
Figure 9 is a perspective view showing a state in which a pair of pressing parts and a reduction gear part provided in an electronic parking brake according to an embodiment of the present invention are assembled.
10 and 11 are diagrams for explaining the operating state of the electronic parking brake according to an 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 to sufficiently convey the idea of the present invention to those skilled in the art. The present invention is not limited to the embodiments presented herein and may be embodied in other forms. In order to clarify the present invention, the drawings may omit illustrations of parts unrelated to the description and may slightly exaggerate the sizes of components to aid understanding.

Figure 1 is a perspective view showing an electronic parking brake according to an embodiment of the present invention, Figure 2 is a rear perspective view showing an electronic parking brake according to an embodiment of the present invention, and Figure 3 is a rear perspective view showing an electronic parking brake according to an embodiment of the present invention. It is a side cross-sectional view showing the electronic parking brake, Figure 4 is a partial perspective view showing the electronic parking brake according to an embodiment of the present invention, and Figure 5 is a pair of pressure brakes provided in the electronic parking brake according to an embodiment of the present invention. It is an exploded perspective view showing a part, and Figure 6 is an exploded perspective view showing the combined state of the driving part, differential gear part, and power transmission part provided in the electronic parking brake according to an embodiment of the present invention, Figure 7 is an assembled perspective view of Figure 6, Figure 8 is an exploded perspective view showing the combined state of the power transmission unit and the reduction gear unit provided in the electronic parking brake according to an embodiment of the present invention, and Figure 9 is an exploded perspective view showing the combined state of the electronic parking brake provided in the electronic parking brake according to an embodiment of the present invention. This is a perspective view showing the state in which the pair of pressurizing parts and the reduction gear part are assembled.

1 to 9, the electronic parking brake 1 according to one aspect of the present invention includes a pair of pressing parts 100 and an actuator 200 for operating the pair of pressing parts 100. It can be included. At this time, the actuator 200 may include a driving unit 210, a differential gear unit 220, a power transmission unit 230, and a reduction gear unit 240. In addition, the electronic parking brake (1) is installed on a carrier (20) on which a pair of brake pads (30) are installed to pressurize a disk (not shown) that rotates with the wheel of the vehicle, and is slidably installed on the carrier (20). It may further include an electronic control unit (not shown) that controls the operation of the caliper housing 10 and the actuator 200 that operate the pair of brake pads 30. Here, the driving unit 210, the differential gear unit 220, the power transmission unit 230, and the reduction gear unit 240 are provided in the actuator housing 201 installed in the caliper housing 10 and form a pair of pressurizing units ( Parking braking force can be implemented by transmitting power to 100).

The unexplained reference numeral '202' is a cover that closes the opening of the actuator housing 201.

The caliper housing 10 is formed to be bent downward on the front side (right side with respect to FIG. 3) to operate a pair of brake pads 30 consisting of an outer brake pad 30 and an inner brake pad 30. It includes a cylinder portion 11 provided with a finger portion 12 and a pair of pressing portions 100, and is slidably fastened to the carrier 20. The cylinder portion 11 and the finger portion 12 are formed as one piece. A braking operation is performed by pressing a pair of brake pads 30 through the piston 110 provided in the finger portion 12 and the cylinder portion 11 of the caliper housing 10 and causing friction with the disc. Since the configuration of this caliper brake is already a well-known technology, detailed description will be omitted.

A pair of pressurizing units 100 may be installed in the caliper housing 10 to receive power from the actuator 200 and convert rotational motion into linear motion. That is, the pair of pressing units 100 are provided to press the brake pad 30, which generates contact friction with the vehicle's disc (not shown). This pair of pressing parts 100 may be arranged side by side within the cylinder part 11. For example, a pair of pressing parts 100 are symmetrically disposed on the left and right sides of the central part of the brake pad 30. Accordingly, the pair of pressurizing units 100 receive power from the actuator 200 and pressurize the brake pad 30 with the same pressurizing load to generate parking braking force due to friction between the brake pad 30 and the disc.

As shown in FIG. 5, this pair of pressing parts 100 each includes a piston 110 and a power conversion unit 120. At this time, since the pair of pressing units 100 are provided to have the same configuration, the description will be based on one pressing unit.

The pressurizing part 100 receives driving force from the piston 110 and the actuator 200 that are slidably inserted into the cylinder part 11 of the caliper housing 10 and converts the rotational motion into linear motion to move the piston 110. It may include a power conversion unit 120 that pressurizes or releases pressure.

The power conversion unit 120 includes a spindle 121 that rotates by receiving driving force within the cylinder unit 11, and a nut ( 123) can be provided. At this time, the nut 123 may be provided to limit rotation inside the piston 110.

The spindle 121 has a predetermined length, and threads may be formed on its outer peripheral surface for coupling to the nut 123. A nut 123 is coupled to one side of the spindle 121 (the front side, which is the right side based on FIG. 3), and the other side (the rear side, which is the left side based on FIG. 3) is connected to the actuator 200 to provide driving force. It is made to receive. For example, the other side of the spindle 121 may be coupled in a spline structure with a reduction output gear 245, which outputs torque through a reduction gear unit 240, which will be described later.

The nut 123 may have a thread formed on the inside to engage the thread of the spindle 121. This nut 123 may be provided inside the piston 110 with limited rotation. Accordingly, the nut 123 moves linearly according to the forward or reverse rotation direction of the spindle 121 and pressurizes or releases the pressure on the piston 110.

This power conversion unit 120 is shown and described as having the spindle 121 and the nut 123 screwed together, but it is not limited to this, and a ball is provided between the spindle 121 and the nut 123 to achieve linear rotational movement. It can be provided with a ball-screw type conversion device that converts it into movement.

The actuator 200 includes a driving unit 210 that generates power, a differential gear unit 220 connected to the driving unit 210, and a power transmission unit 230 connecting the differential gear unit 220 and the reduction gear unit 240. ) and a reduction gear unit 240 that transmits output torque to the pair of pressurizing units 100. This actuator 200 may be accommodated in the actuator housing 201 and installed outside the rear of the caliper housing 10 or in a vehicle.

The driving unit 210 may be configured as a motor that receives power by operating a switch (not shown) provided in the driver's seat of the vehicle and converts electrical energy into mechanical rotational kinetic energy. Control of the braking operation according to the operation signal of the switch may be performed by the vehicle's electronic control unit (ECU), not shown. The rotational force generated through the drive unit 210 is transmitted to the differential gear unit 220 through the drive gear 221 coupled to the rotation shaft 211.

The differential gear unit 220 is connected to the driving unit 210 and is provided to rotate by the rotational force of the driving unit 210. This differential gear unit 220 includes a driving gear 221, a ring gear 222, a first shaft 224, a second shaft 225, a first gear 223, and a second gear 226. ) may include.

The ring gear 222 has a hollow portion 222a whose center is hollow, and its outer peripheral surface is provided to rotate in engagement with the drive gear 221.

The first gear 223 is located in the hollow portion 222a of the ring gear 222 and is coupled to rotate with the ring gear 222. As shown, the first gear 223 consists of a pair and is coupled to the inner surface of the ring gear 222 to face each other with a 180-degree phase difference.

The first shaft 224 is arranged to face the hollow part 222a on one side of the ring gear 222, and the second shaft 225 is arranged to face the hollow part 222a on the other side of the ring gear 222. do. That is, the first shaft 224 and the second shaft 225 are arranged in a straight line at a certain distance from each other. Although not shown, the first shaft 224 and the second shaft 225 may be rotatably supported on the actuator housing 201.

The second gear 226 may be provided as a pair to be vertically engaged with the pair of first gears 223. Accordingly, the second gear 226 may be installed on one end of the first shaft 224 and the other end of the second shaft 225 to face each other. At this time, the second gear 226 may be coupled to rotate together with the first shaft 224 and the second shaft 225. Therefore, the second gear 226 rotates in engagement with the first gear 223, which rotates together with the rotation of the ring gear 222, and the first shaft 224 coupled with the second gear 226 and the The two shafts 225 rotate in the same direction.

This differential gear unit 220 allows the first shaft 224 and the second shaft 225 to rotate uniformly in the same direction, so that power can be equally transmitted to the power transmission unit 230, which will be described later. By combining the first gear 223 and the second gear 226 in the hollow portion 222a of the ring gear 222, the structure is simplified, which has the effect of reducing the volume and manufacturing cost compared to the prior art.

The power transmission unit 230 is directly connected to the differential gear unit 220 and the reduction gear unit 240, which will be described later, and transmits the rotational force of the driving unit 210 to the reduction gear unit 240. These power transmission units 230 may be provided as a pair to be connected to the first shaft 224 and the second shaft 225 of the differential gear unit 220, respectively. Specifically, the power transmission unit 230 may include a worm gear 231 installed on the first shaft 224 and the second shaft 225, respectively, and a worm wheel gear 233 that engages and rotates the worm gear 231. there is. That is, the pair of power transmission units 230 each consists of one worm gear 231 and one whim wheel gear 233, and may be provided to have the same reduction ratio.

Meanwhile, as the power transmission unit 230 is provided with a worm gear assembly structure, the friction between gears increases, so that the parking state is maintained by implementing a self-locking function even if the operation of the drive unit 210 is stopped after the parking braking force is achieved. .

The reduction gear unit 240 is respectively connected to a pair of power transmission units 230 and is provided to transmit power to the pair of pressurizing units 100, respectively. Accordingly, the reduction gear unit 240 may be provided as a pair so as to be respectively connected to a pair of pressing units 100. Since the pair of reduction gear units 240 are provided to have substantially the same structure, the description below will be based on one reduction gear unit.

The reduction gear unit 240 includes a reduction sun gear 241, a plurality of reduction planetary gears 242 meshed on the outside of the reduction sun gear 241, and a reduction ring with internal gears to accommodate the plurality of reduction planetary gears 242. It may include a reduction carrier 244 that rotatably supports the gear 243 and the plurality of reduction planet gears 242 and is installed to rotate coaxially with the reduction sun gear 241 and outputs rotational power.

The reduction sun gear 241 may be provided at the center of the worm wheel gear 233. As shown, the reduction sun gear 241 may be provided at the center of the worm wheel gear 233 and rotate together with the worm wheel gear 233. At this time, the reduction sun gear 241 may be provided integrally with the center of the worm wheel gear 233 or may be provided separately and coupled thereto.

A plurality of reduction planetary gears 242 are provided in three or four pieces in consideration of efficiency and economy, and are rotatable on branch axes in four directions branched from the reduction carrier 244, respectively.

The reduction ring gear 243 accommodates a plurality of reduction planetary gears 242 inside, and an internal gear is provided to mesh with the plurality of reduction planetary gears 242. This reduction ring gear 243 may be provided to be fixed to the actuator housing 201. Accordingly, the plurality of reduction planetary gears 242 may rotate and rotate within the reduction ring gear 243 according to the rotation of the reduction sun gear 241.

The reduction carrier 244 may be formed in the form of a disk, and on one side is provided with a plurality of planetary gear branch shafts (not shown) spaced apart at predetermined intervals along the circumferential direction, and at the center is the spindle 121 of the pressing unit 100 and An output gear 245 may be provided to be coupled. At this time, the reduction output gear 245 is formed coaxially with the reduction sun gear 241.

The reduction output gear 245 may be spline-coupled with the spindle 121 to transmit rotational force to the spindle 121, or may be coupled to mesh with the spindle 121 through a gear. Accordingly, the spindle 121 rotates together with the rotation of the output carrier 244.

The reduction gear unit 240 as described above has a planetary gear assembly structure to amplify the driving force and transmits it to the pressing unit 100. At this time, the gear ratio of the reduction gear unit 240 can be adjusted to provide the required load through one driving unit 210 and a pair of pressing units 100. For example, the reduction gear unit 240 may be provided with a multi-stage planetary gear assembly structure to transmit the required torque. That is, as shown, the reduction gear unit 240 may be composed of a two-stage planetary gear assembly (240a, 240b). Each of these planetary gear assemblies (240a, 240b) may be composed of a reduction carrier 244 having a reduction sun gear 241, a plurality of reduction planet gears 242, a reduction ring gear 243, and a reduction output gear 245. there is. Accordingly, the reduction sun gear 241 of the first-stage planetary gear assembly 240a is provided to rotate together with the worm wheel gear 233, and the reduction output gear 245 is the reduction sun gear of the second-stage planetary gear assembly 240b ( 241). These multi-stage planetary gear assemblies (240a, 240b) are connected to the centers of each reduction sun gear (241, 245) and the reduction carrier (244) by one central axis (246). Therefore, even if the planetary gear assembly is connected in addition to the two-stage planetary gear assembly structure, torque is ultimately output through the reduction output gear 245 of the reduction carrier 244.

Hereinafter, the operating state for generating parking braking force of the electronic parking brake according to an embodiment of the present invention will be described with reference to FIGS. 10 and 11.

Figure 10 shows a state before the driver applies the parking brake after stopping the vehicle, in which the brake pad 30 is not pressed by the pair of pressing parts 100 and is spaced apart from the disk (not shown).

In this state, when the parking brake is activated, the drive unit 210 generates rotational force, causing the drive gear 221 coupled to the rotation shaft 211 to rotate, and the differential gear unit 220 engaged with the drive gear 221 to rotate. .

Specifically, referring to FIG. 11, the ring gear 222 engaged with the drive gear 221 rotates, and the pair of first gears 223 coupled with the ring gear 222 rotate together, The pair of second gears 226 engage with the first gear 223 and rotate. At this time, the pair of second gears 226 are coupled to the first shaft 224 and the second shaft 225, respectively, so that the first shaft 224 and the second shaft 225 are connected to the second gear 226. rotates in the same direction.

The worm gear 231 coupled to the first shaft 224 and the second shaft 225 rotates together with the rotation of the first shaft 224 and the second shaft 225 and transmits rotational force to the worm wheel gear 233. I do it. At this time, the worm wheel gear 233 is provided as a pair and is meshed with the worm gear 231 provided on the first shaft 224 and the worm gear 231 provided on the second shaft 225, respectively, and rotates in the same direction.

Rotational force is output to the spindle 121 connected to the reduction gear unit 240 through the reduction sun gear 241 that rotates together with the worm wheel gear 233. Specifically, the reduction sun gear 241 is provided at the lower center of the worm wheel gear 233, rotates together with the worm wheel gear 233, and transmits rotational force to the plurality of reduction planetary gears 242, and the plurality of reduction planetary gears 242 rotates and rotates within the reduction ring gear 243 according to the rotation of the reduction sun gear 241. Therefore, the reduction carrier 244 rotates coaxially with the reduction sun gear 241 by the plurality of revolving planetary gears 242 and outputs rotational force to the spindle 121. At this time, in order to transmit sufficient torque to the pressing unit 100 to generate stable parking braking force, the reduction gear unit 240 is provided with a two-stage planetary gear assembly (240a, 240b).

As the spindle 121 rotates, the nut 123 converts the rotational force into linear motion and presses the piston 110. Accordingly, the piston 110 compresses the brake pad 30 with a disc (not shown), thereby generating parking braking force.

After braking, the operation of the driving unit 210 is stopped, and reverse rotation of the spindle 121 is prevented by the power transmission unit 230 with a large reduction ratio. Accordingly, the braking state is maintained as is unless the driving unit 210 is driven again.

When the driver releases the brakes, he or she operates the parking switch on the driver's seat to release the brakes. At this time, the driving unit 210 generates rotational force in the reverse direction during parking braking, and the differential gear unit 220, power transmission unit 230, reduction gear unit 240, and spindle 121 rotate in the reverse direction during parking braking. , the nut 123 releases the pressure of the piston 110 and the parking force is released.

As described above, although the present invention has been described with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the following will be understood by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalence of the patent claims to be described.

1: Electronic parking brake 10: Caliper housing
100: pressurizing part 110: piston
120: Power conversion unit 200: Actuator
210: driving unit 220: differential gear unit
230: Power transmission unit 240: Reduction gear unit

Claims (6)

A pair of pressurizing units provided in the caliper housing to convert rotational movement into linear movement to pressurize the brake pads;
A driving unit that receives power from the outside and generates power;
A differential gear unit connected to the drive unit and provided so that a first shaft and a second shaft arranged in a straight line rotate in the same direction by the rotational force of the drive unit;
a pair of power transmission units respectively connected to the first shaft and the second shaft; and
An electronic parking brake comprising a reduction gear unit respectively connected to the pair of power transmission units and transmitting rotational force to the pair of pressing units. According to paragraph 1,
The differential gear unit,
A driving gear coupled to the rotating shaft of the driving unit;
A ring gear having a ring shape with a hollow center, the outer surface of which rotates in engagement with the driving gear;
a pair of first gears installed to face each other on the inner surface of the ring gear and rotating together with the ring gear;
The first shaft disposed on one side of the ring gear toward the hollow;
the second shaft disposed on the other side of the ring gear toward the hollow; and
An electronic parking brake comprising: a pair of second gears installed to face each other on the first shaft and the second shaft so as to engage vertically with the pair of first gears. According to paragraph 1,
The pair of power transmission units,
Worm gears installed on the first shaft and the second shaft; and
An electronic parking brake comprising a worm wheel gear that engages and rotates with the worm gear. According to paragraph 3,
The pair of reduction gear units,
a reduction sun gear coupled to the center of the worm wheel gear and rotating together with the rotation of the worm wheel gear;
a plurality of reduction planetary gears meshed on the outside of the reduction sun gear;
a reduction ring gear made of internal gears to accommodate the plurality of reduction planetary gears; and
An electronic parking brake comprising: a reduction carrier that rotatably supports the plurality of reduction planet gears and is installed to rotate coaxially with the reduction sun gear to output rotational power. According to paragraph 1,
An electronic parking brake wherein the pair of reduction gear units each have a multi-stage planetary gear assembly structure. According to paragraph 1,
The pair of pressurizing parts,
A piston slidably inserted into the cylinder portion of the caliper housing; and
A spindle that rotates by receiving driving force from the reduction gear unit within the cylinder unit, and a spindle connected to the spindle that moves forward or backward by forward and reverse rotation of the spindle and is provided on the inside of the piston to press or release the piston. An electronic parking brake including a power conversion unit having a nut.

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