Transmission device for vehicle braking system

Abstract

The invention relates to the technical field of brake systems, in particular to a transmission device for a vehicle brake system, which comprises a motor assembly, a gear reducer, a ball screw pair, a brake caliper body, a first brake friction block and a brake disc, the gear reducer comprises an input gear shaft, and the input gear shaft is in transmission connection with an output shaft of the motor assembly; the input gear shaft, the first-stage planetary gear transmission pair, the sun gear, the second-stage planetary gear transmission pair, the speed reducer output shaft and the ball screw pair are sequentially in transmission connection, a first friction pad is arranged at the end, facing the sun gear, of the input gear shaft, and a second friction pad is arranged at the end, coaxially facing the sun gear, of the speed reducer output shaft. The input gear shaft is separated from the sun gear, and the sun gear is separated from the speed reducer output shaft, so that impact in the operation process is avoided, and noise is reduced; and the friction area with the sun gear is reduced, and the friction coefficient is reduced, so that the friction loss is reduced, and the noise is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of brake systems, and in particular to a transmission device for a vehicle brake system. Background Art

[0002] In recent years, with the rapid development of automobile electrification and intelligent driving technology, higher requirements have been placed on the drive-by-wire chassis, and brake-by-wire (BBW) is a key component of the drive-by-wire chassis technology.

[0003] Braking by wire is divided into electronic hydraulic braking (EHB) and electronic mechanical braking (EMB). Compared with EHB, EMB completely abandons the brake fluid and hydraulic pipelines of the traditional braking system, and installs an independent electronic mechanical brake on each wheel. The motor directly drives the caliper to complete the braking, which is also called a dry braking system. The EMB system is mainly composed of sensors, electronic control units, motors and brake actuators. The EMB structure is very simple and compact, making the layout, assembly and maintenance of the braking system more convenient, and the braking response faster and more accurate. Since the use of brake fluid is completely abandoned, it is more environmentally friendly and is the development direction of future vehicles.

[0004] The function of the transmission mechanism is to convert the torque of the motor into the brake clamping force of the caliper. It is a key component of the EMB system. Its transmission efficiency, operating noise, precision and reliability directly affect the performance of the EMB system. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a transmission device for a vehicle braking system, which can effectively reduce the operating noise of the transmission mechanism during operation.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: a transmission device for a vehicle braking system, comprising a motor assembly, a gear reducer, a ball screw pair, a brake caliper body, a first brake friction block and a brake disc, the ball screw pair is arranged on the inner side of the brake caliper body, the output shaft of the motor assembly is transmission-connected with the input gear shaft of the gear reducer, the output shaft of the gear reducer is transmission-connected with the first brake friction block of the ball screw pair to drive the first brake friction block close to the brake disc, the gear reducer comprises an input gear shaft, a first-stage planetary gear transmission pair, a sun gear, a second-stage planetary gear transmission pair and a reducer output shaft, the input gear shaft and The output shaft of the motor assembly is transmission connected, the input gear shaft is transmission connected to the input end of the first-stage planetary gear transmission pair, the output end of the first-stage planetary gear transmission pair is transmission connected to the sun gear, the sun gear is transmission connected to the input end of the second-stage planetary gear transmission pair, the output end of the second-stage planetary gear transmission pair is transmission connected to the reducer output shaft, the reducer output shaft is transmission connected to the ball screw pair, the input gear shaft, the sun gear and the reducer output shaft are coaxially arranged, and a first friction pad is arranged at one end of the input gear shaft facing the sun gear, and a second friction pad is arranged at one end of the reducer output shaft coaxially facing the sun gear.

[0007] The beneficial effects of the present invention are as follows: a two-stage planetary gear transmission pair is connected in series, and a first friction pad and a second friction pad are respectively arranged on the end surfaces of the input gear shaft and the reducer output shaft facing each other, so as to isolate the input gear shaft from the sun gear and the sun gear from the reducer output shaft, avoid impact during operation, and reduce noise; and reduce the friction area with the sun gear, reduce the friction coefficient, thereby reducing friction loss and further reducing noise.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the motor assembly includes a motor housing, a motor rotor and a motor stator, the motor stator is fixedly arranged in the motor housing, the motor rotor is rotatably arranged on the inner side of the motor stator, an axial hole is arranged in the motor rotor, the input gear shaft is coaxially arranged with the axial hole, and one end of the input gear shaft is fixedly arranged in the axial hole.

[0010] The beneficial effect of adopting the above further solution is that the rotation of the motor rotor drives the input gear shaft in the shaft hole to rotate axially, and the transmission structure is arranged inside the motor, which greatly reduces unnecessary waste of space.

[0011] Further, the first-stage planetary gear transmission pair includes an inner gear ring, a planetary disk and a first-stage planetary wheel, the inner gear ring is arranged in the shaft hole, the planetary disk is rotatably arranged in the inner gear ring, the planetary disk is coaxially arranged with the inner gear ring, one end of the sun gear is coaxially fixedly connected with the planetary disk, a plurality of first cylindrical pins are arranged on the side of the planetary disk facing the input gear shaft, the first-stage planetary wheel is rotatably sleeved on the first cylindrical pin, the first-stage planetary wheel is meshed with the inner gear ring, and the other end of the input gear shaft is meshed with the plurality of first-stage planetary wheels.

[0012] The beneficial effect of adopting the above further scheme is that the rotation of the input gear shaft drives the rotation of the planetary gear, thereby driving the primary planetary gear to rotate in the inner ring gear, and then drives the sun gear to rotate, thereby realizing a primary reduction transmission.

[0013] Furthermore, an inner gear ring flange is fixedly provided at one end of the inner gear ring facing the brake caliper body, a plurality of third cylindrical pins are fixedly provided on the inner gear ring flange, the brake caliper body is provided with pin holes corresponding one to one to the third cylindrical pins, a step hole is provided at the mouth of the pin hole, a vibration damping ring is embedded in the step hole, and one end of the third cylindrical pin away from the inner gear ring flange passes through the vibration damping ring and is inserted into the pin hole.

[0014] The beneficial effect of adopting the above further scheme is: when the motor mechanism is started, the input gear shaft will be subjected to an instantaneous impact force (or torque), and the impact force is transmitted to the inner ring gear. The inner ring gear will first squeeze the damping ring when subjected to the impact force, and the damping ring will absorb the generated impact energy, thereby reducing impact damage. When the impact force (or torque) exceeds a certain value, the damping ring will no longer be further compressed. At this time, the third cylindrical pin will abut against the small hole in the brake caliper body, limiting the rotation of the inner ring gear.

[0015] Furthermore, the secondary planetary gear transmission pair includes a secondary planetary gear, an output shaft flange is fixedly provided on one end of the reducer output shaft facing the sun gear, a plurality of second cylindrical pins are fixedly provided on the side of the output shaft flange facing the sun gear, the secondary planetary gear is rotatably provided on the second cylindrical pins, and the secondary planetary gear is meshed with the sun gear and the inner gear ring.

[0016] The beneficial effect of adopting the above further scheme is that the sun gear rotates under the transmission action of the first-stage planetary gear transmission pair, thereby driving the second-stage planetary gear to rotate along the inner ring gear, and then driving the output shaft of the reducer to rotate, realizing the second-stage reduction transmission and reducing the space occupied by the overall structure.

[0017] Furthermore, a flat gasket is provided between the brake caliper body and a side of the output shaft flange away from the sun gear.

[0018] The beneficial effect of adopting the above further scheme is that the provision of the flat gasket can reduce the friction loss of the rotation between the output shaft and the end face of the sliding bearing. The flat gasket has a simple structure, is easy to process and has high precision, which reduces the difficulty of processing the output shaft and isolates the impact of the cylindrical pin hole of the output shaft flange on the scratching of the end face of the sliding bearing.

[0019] Furthermore, a sliding bearing is provided in the center hole of the brake caliper body, the reducer output shaft is inserted in the sliding bearing, the screw of the ball screw pair is splined to the end of the reducer output shaft away from the sun gear, the end of the nut of the ball screw pair away from the sun gear is axially in contact with the first brake friction block, and a mounting hole is provided on the brake caliper body, the mounting hole and the end of the nut of the ball screw pair facing the sun gear are arranged opposite to each other, a vibration damping pad is provided in the mounting hole, and the vibration damping pad protrudes from the mounting hole at one end of the nut of the ball screw pair facing the sun gear.

[0020] The beneficial effect of adopting the above further solution is that when the motor assembly is reversed, the retraction of the nut will first squeeze the vibration-damping pad, and the vibration-damping pad will absorb part of the impact energy generated by the return of the nut, further reducing noise.

[0021] Furthermore, one end of the mounting hole away from the nut of the ball screw pair is a V-shaped countersunk hole, and one end of the vibration damping pad away from the nut of the ball screw pair is a frustum-shaped structure matching the V-shaped countersunk hole.

[0022] The beneficial effect of adopting the above further solution is that the frustum-shaped structure of the vibration damping pad and the matching V-shaped countersunk hole can effectively prevent the vibration damping pad from axially dislodging, and the V-shaped countersunk hole can provide deformation space for the vibration damping pad to deform when under pressure.

[0023] Furthermore, a locking nut is threadedly connected to the end of the reducer output shaft away from the sun gear, an inner ring platform is arranged on the inner side of the screw of the ball screw pair, the inner ring platform is connected to the reducer output shaft through a spline, a ring groove is arranged on the side of the locking nut facing the inner ring platform, a wave spring is arranged between the ring groove and the side wall of the inner ring platform; a plane thrust bearing and a force sensor are arranged in sequence between the other side of the inner ring platform and the inner wall of the brake caliper body.

[0024] The beneficial effect of adopting the above-mentioned further scheme is: the locking nut presses the screw, the plane thrust bearing and the force sensor together against the brake caliper body through the wave spring, and the wave spring provides a preload force to eliminate the axial assembly clearance of the screw, the plane thrust bearing, the force sensor, etc. caused by processing errors; the plane thrust bearing provides axial support, transmits the axial force of the ball screw pair to the force sensor, and isolates the rotational motion of the screw from the force sensor, and the force sensor and the brake caliper body are relatively stationary.

[0025] Furthermore, an input shaft countersunk hole is provided at one end of the input gear shaft facing the sun gear, and one end of the first friction pad is embedded in the input shaft countersunk hole; an output shaft countersunk hole is provided at one end of the reducer output shaft coaxially facing the sun gear, and one end of the second friction pad is embedded in the output shaft countersunk hole.

[0026] The beneficial effect of adopting the above further solution is that the installation of the first friction pad and the second friction pad is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention;

[0028] Figure 2 It is a schematic diagram of the installation of the gear reducer and the ball screw pair in the present invention;

[0029] Figure 3 For the present invention Figure 2 AA surface section view in;

[0030] Figure 4 For the present invention Figure 2 BB surface section view in;

[0031] Figure 5 For the present invention Figure 2 The CC section view in the figure;

[0032] Figure 6 For the present invention Figure 4 DD plane section view in;

[0033] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0034] 100, motor assembly; 101, motor housing; 102, motor rotor; 103, motor stator;

[0035] 200, gear reducer; 201, inner gear ring; 202, planetary disc; 203, input gear shaft; 204, first friction pad; 205, first cylindrical pin; 206, primary planetary gear; 207, sun gear; 208, second cylindrical pin; 209, secondary planetary gear; 210, reducer output shaft; 211, second friction pad; 212, third cylindrical pin; 213, input shaft countersink; 214, output shaft countersink;

[0036] 300, ball screw pair; 301, screw; 302, nut; 303, inner ring;

[0037] 1. Force sensor; 2. Planar thrust bearing; 3. Fourth cylindrical pin; 4. Wave spring; 5. Lock nut; 6. End cover; 7. Sliding bearing; 8. Flat washer; 9. Vibration damping ring; 10. Vibration damping pad; 11. Flanging; 12. Boss end face; 13. Ring groove;

[0038] 401, brake caliper body; 402, first brake friction block; 403, brake disc; 404, second brake friction block; 405, countersunk groove; 406, convex ring; 407, piston hole; 408, pin shaft hole bottom; 409, step hole; 410, pin hole; 411, V-shaped countersunk hole; 412, piston hole bottom; 413, caliper body countersunk hole; 414, mounting hole. DETAILED DESCRIPTION

[0039] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0040] like Figures 1 to 6 As shown, in an embodiment of the present invention, it includes a motor assembly 100, a gear reducer 200, a ball screw pair 300, a brake caliper body 401, a first brake friction block 402 and a brake disc 403, the ball screw pair 300 is arranged on the inner side of the brake caliper body 401, the output shaft of the motor assembly 100 is transmission-connected with the input gear shaft 203 of the gear reducer 200, and the output shaft of the gear reducer 200 is transmission-connected with the first brake friction block 402 of the ball screw pair 300 for driving the first brake friction block 402 Close to the brake disc 403, specifically, the motor assembly 100 includes a motor housing 101, a motor rotor 102 and a motor stator 103. The motor housing 101 is fixedly connected to the brake caliper body 401 by bolts, the motor stator 103 is fixedly arranged in the motor housing 101, the motor rotor 102 is rotatably arranged on the inner side of the motor stator 103, an axial hole is arranged in the motor rotor 102, the input gear shaft 203 is coaxially arranged with the axial hole, and one end of the input gear shaft 203 is fixedly arranged in the axial hole.

[0041] like Figure 1 , Figure 2 , Figure 3As shown, the gear reducer 200 includes an input gear shaft 203, a primary planetary gear transmission pair, a sun gear 207, a secondary planetary gear transmission pair and a reducer output shaft 210, the input gear shaft 203 is drivingly connected to the output shaft of the motor assembly 100, the input gear shaft 203 is drivingly connected to the input end of the primary planetary gear transmission pair, the output end of the primary planetary gear transmission pair is drivingly connected to the sun gear 207, the sun gear 207 is drivingly connected to the input end of the secondary planetary gear transmission pair, the output end of the secondary planetary gear transmission pair is drivingly connected to the reducer output shaft 210, the reducer output shaft 210 is drivingly connected to the ball screw pair 300, the input gear shaft 203, the sun gear 207 and the reducer output shaft 210 are coaxially arranged, and a first friction pad 204 is arranged at one end of the input gear shaft 203 facing the sun gear 207, and a second friction pad 211 is arranged at one end of the reducer output shaft 210 coaxially facing the sun gear 207.

[0042] like Figure 1 As shown, specifically, an input shaft counterbore 213 is provided at one end of the input gear shaft 203 facing the sun gear 207, and one end of the first friction pad 204 is embedded in the input shaft counterbore 213; an output shaft counterbore 214 is provided coaxially at one end of the reducer output shaft 210 facing the sun gear 207, and one end of the second friction pad 211 is embedded in the output shaft counterbore 214.

[0043] like Figure 2 , Figure 3 As shown, in an embodiment of the present invention, the first-stage planetary gear transmission pair includes an inner gear ring 201, a planetary disk 202 and a first-stage planetary gear 206, the inner gear ring 201 is arranged in the shaft hole, the planetary disk 202 is rotatably arranged in the inner gear ring 201, the planetary disk 202 is coaxially arranged with the inner gear ring 201, one end of the sun gear 207 is coaxially fixedly connected with the planetary disk 202, a plurality of first cylindrical pins 205 are arranged on the side of the planetary disk 202 facing the input gear shaft 203, the first-stage planetary gear 206 is rotatably sleeved on the first cylindrical pin 205, the first-stage planetary gear 206 is meshed with the inner gear ring 201, and the other end of the input gear shaft 203 is meshed with the plurality of first-stage planetary gears 206, the rotation of the input gear shaft 203 drives the rotation of the planetary wheels, thereby driving the first-stage planetary gear 206 to rotate in the inner gear ring 201, and then driving the sun gear 207 to rotate, thereby realizing a first-stage reduction transmission.

[0044] The inner gear ring 201 is fixedly provided with an inner gear ring 201 flange at one end facing the brake caliper body 401, and a plurality of third cylindrical pins 212 are fixedly provided on the inner gear ring 201 flange. The brake caliper body 401 is provided with pin holes 410 corresponding to the third cylindrical pins 212 one by one, and a step hole 409 is provided at the orifice of the pin hole 410, and a vibration damping ring 9 is embedded in the step hole 409. The end of the third cylindrical pin 212 away from the inner gear ring 201 flange passes through the vibration damping ring 9 and is inserted into the pin hole 410. The outer diameter of the third cylindrical pin 212 is slightly smaller than the inner diameter of the pin hole 410. When the motor mechanism is started, the input gear shaft 203 will be subjected to an instantaneous impact force (or torque), which is transmitted to the inner gear ring 201. The inner gear ring 201 will first squeeze the damping ring 9 when subjected to the impact force, and the damping ring 9 will absorb the generated impact energy, thereby reducing impact damage. When the impact force (or torque) exceeds a certain value, the damping ring 9 will no longer be further compressed. At this time, the third cylindrical pin 212 will abut against the small hole in the brake caliper body 401, limiting the rotation of the inner gear ring 201.

[0045] like Figure 2 As shown, preferably, the secondary planetary gear transmission pair includes a secondary planetary gear 209, an output shaft flange is fixedly provided at one end of the reducer output shaft 210 facing the sun gear 207, a plurality of second cylindrical pins 208 are fixedly provided on the side of the output shaft flange facing the sun gear 207, the secondary planetary gear 209 is rotatably provided on the second cylindrical pin 208, the secondary planetary gear 209 is meshed with the sun gear 207 and the inner gear ring 201, the sun gear 207 rotates under the transmission action of the primary planetary gear transmission pair, thereby driving the secondary planetary gear 209 to rotate along the inner gear ring 201, and then driving the reducer output shaft 210 to rotate, realizing secondary reduction transmission, and reducing the space occupied by the overall structure.

[0046] A sliding bearing 7 is provided in the center hole of the brake caliper body 401, and the reducer output shaft 210 is inserted in the sliding bearing 7. The screw 301 of the ball screw pair 300 is splined to the end of the reducer output shaft 210 away from the sun gear 207, and the nut 302 of the ball screw pair 300 is axially in contact with the first brake friction block 402 at one end away from the sun gear 207. Specifically, the end of the nut 302 away from the sun gear 207 is fixedly connected to the end cover 6 by threads, and the end cover 6 abuts against the first brake friction block 402.

[0047] In an embodiment of the present invention, a plurality of pin shaft holes are provided on the brake caliper body 401, and the fourth cylindrical pin 3 is provided in the pin shaft hole, one end of the fourth cylindrical pin 3 abuts against the bottom 408 of the pin shaft hole, and the other end of the fourth cylindrical pin 3 abuts against the end face of the flange of the inner gear ring 201; an arc groove connected to the pin shaft hole is provided on the outer circle of the nut 302, and the fourth cylindrical pin 3 is partially arranged in the arc groove to prevent the nut 302 from axial rotation.

[0048] The brake caliper body 401 is provided with a mounting hole 414, and the mounting hole 414 is arranged opposite to the end of the nut 302 of the ball screw pair 300 facing the sun gear 207. In the brake caliper body 401, the space for the nut 302 to slide is the piston hole 407, and the mounting hole 414 is arranged on the bottom 412 of the piston hole. A vibration damping pad 10 is provided in the mounting hole 414, and the vibration damping pad 10 protrudes from the mounting hole 414 at one end of the nut 302 of the ball screw pair 300. When the motor assembly 100 reverses, the nut 302 retreats and first squeezes the vibration damping pad 10. The vibration damping pad 10 absorbs part of the impact energy generated by the return of the nut 302, thereby further reducing noise.

[0049] A flat gasket 8 is disposed between the side of the output shaft flange away from the sun gear 207 and the brake caliper body 401 . Specifically, the flat gasket 8 rotates in contact with the end surface of the sliding bearing 7 through friction, thereby reducing friction loss.

[0050] Specifically, a center hole of the brake caliper body 401 is provided with a recessed groove 405 at one end facing the sun gear 207, and a flange 11 extending toward the periphery is provided at one end of the sliding bearing 7 facing the sun gear 207. The flange 11 is arranged in the recessed groove 405, and the flat gasket 8 is arranged between the output shaft flange and the flange 11, with one side abutting against the flange 11 and the other side abutting against the output shaft flange.

[0051] The end of the mounting hole 414 away from the nut 302 of the ball screw pair 300 is a V-shaped countersunk hole 411, and the end of the vibration damping pad 10 away from the nut 302 of the ball screw pair 300 is a frustum-shaped structure matching the V-shaped countersunk hole 411, and one end of the frustum-shaped structure abuts against the end surface of the flange of the inner gear ring 201. The frustum-shaped structure of the vibration damping pad 10 and the V-shaped countersunk hole 411 matching it can effectively prevent the vibration damping pad 10 from axially dislodging, and the V-shaped countersunk hole 411 can provide deformation space for the deformation of the vibration damping pad 10 when it is under pressure.

[0052] In an embodiment of the present invention, a locking nut 5 is threadedly connected to one end of the reducer output shaft 210 away from the sun gear 207, an inner ring stage 303 is arranged on the inner side of the lead screw 301 of the ball screw pair 300, and the inner ring stage 303 is connected to the reducer output shaft 210 through a spline, and a ring groove 13 is arranged on the side of the locking nut 5 facing the inner ring stage 303, and a wave spring 4 is arranged between the ring groove 13 and the side wall of the inner ring stage 303, and the wave spring 4 is arranged so that a certain gap is left between the boss end face 12 of the locking nut 5 (the end face of the wave spring 4 facing the inner ring stage 303 on the side of the ring groove 13 close to the axis of the locking nut 5) and the bottom of the left hole of the lead screw 301, and the lead screw 301 and the reducer output shaft 210 can slide slightly axially relative to each other; the other side of the inner ring stage 303 A plane thrust bearing 2 and a force sensor 1 are arranged in sequence between the inner wall of the brake caliper body 401. The locking nut 5 presses the lead screw 301, the plane thrust bearing 2 and the force sensor 1 together against the brake caliper body 401 through the wave spring 4. Specifically, a convex ring 406 is provided on the inner wall of the brake caliper body 401. The side of the force sensor 1 away from the plane thrust bearing 2 abuts against the side of the convex ring 406. The wave spring 4 provides a preload force to eliminate the axial assembly clearance of the lead screw 301, the plane thrust bearing 2, the force sensor 1, etc. caused by processing errors; the plane thrust bearing 2 provides axial support, transmits the axial force of the ball screw pair 300 to the force sensor 1, and isolates the rotational movement of the lead screw 301 from the force sensor 1. The force sensor 1 and the brake caliper body 401 are relatively stationary.

[0053] The motor assembly 100 is a power source. The motor assembly 100 drives the input gear shaft 203 to rotate. The first-stage planetary gear 206 meshes with the input gear shaft 203 and the inner gear ring 201 to rotate, and drives the planetary disc 202 and the sun gear 207 to rotate. The second-stage planetary gear 209 meshes with the sun gear 207 and the inner gear ring 201 to rotate, and drives the reducer output shaft 210 to rotate. The reducer output shaft 210 drives the lead screw 301 to rotate. The lead screw 301 rotates to drive the nut 302 to perform linear translational motion. The pin hole 410 on the brake caliper body 401 and the damping ring 9 The torsion of the third cylindrical pin 212 and the inner gear ring 201 is limited, and the vibration damping ring 9 absorbs the impact energy when the third cylindrical pin 212 and the inner gear ring 201 are torsion; when the planetary gear reducer 200 is running, the sun gear 207 rotates relative to the input gear shaft 203 and the reducer output shaft 210, and due to the axial force of the helical gear, the sun gear 207 will move axially, and the first friction pad 204 and the second friction pad 211 arranged between the three play the role of reducing friction loss and buffering vibration; the sliding bearing 7 radially and axially supports and positions the reducer output shaft 210; the caliper body countersunk hole 413 radially positions the inner gear ring 201, and axially limits the inner gear ring 201 with the motor housing 101; the locking nut 5 presses the screw 301, the plane thrust bearing 2, and the force sensor 1 together against the brake caliper body 401 through the wave spring 4, and the output shaft flange and the flat gasket 8 are axially pressed against the sliding bearing 7. The wave spring 4 provides a preload elastic force to eliminate the axial assembly clearance caused by the processing error of the screw 301, the bearing, the force sensor 1, the output shaft, etc.; the plane thrust bearing 2 provides axial support to transmit the axial force of the ball screw pair 300 to the force sensor 1 , and isolates the rotational movement of the lead screw 301 from the force sensor 1, and the force sensor 1 and the brake caliper body 401 are relatively stationary; the pin hole 410 of the brake caliper body 401 positions the fourth cylindrical pin 3, and the fourth cylindrical pin 3 limits the rotation of the nut 302 to ensure that the nut 302 moves in a straight line; the piston hole bottom 412 of the brake caliper body 401 axially limits the return of the nut 302, and the vibration damping pad 10 absorbs the impact energy when the nut 302 returns, and the V-shaped countersunk hole 411 of the brake caliper body 401 prevents the vibration damping pad 10 from axially disengaging, and serves as a deformation space when the vibration damping pad 10 is under pressure.

[0054] When braking is required, the motor assembly 100 drives the lead screw 301 to rotate according to the instructions issued by the control unit through the deceleration and torque increase of the gear reducer 200, and the ball screw pair 300 converts the rotational motion of the lead screw 301 into the linear motion of the nut 302. The nut 302 and the end cover 6 push the first brake friction block 402 and the second brake friction block 404 to clamp the brake disc 403. The brake disc 403 is fixed together with the wheel and rotates, so that the vehicle stops. In this process, the force sensor 1 collects the magnitude of the output clamping force in real time, and changes the magnitude of the brake clamping force by controlling the displacement of the nut 302. On the contrary, by controlling the motor assembly 100 to reverse and drive the nut 302 to retreat, the end cover 6 is separated from the brake friction block, and the brake clamping force is released to end braking.

[0055] When the motor assembly 100 is started or reversed, the gear mechanism will be subjected to an instantaneous impact force (or torque). The impact force generated by the inner ring gear 201 will first squeeze the damping ring 9, and the damping ring 9 will absorb the generated impact energy. When the impact force (or torque) exceeds a certain value, the damping ring 9 will no longer be further compressed. At this time, the third cylindrical pin 212 will abut against the pin hole 410 of the brake caliper body 401, limiting the rotation of the inner ring gear 201.

[0056] When the motor assembly 100 reverses and the nut 302 returns, the nut 302 will first squeeze the vibration-damping pad 10, and the vibration-damping pad 10 will absorb part of the impact energy generated. The nut 302 continues to retreat and finally stops against the piston hole bottom 412 of the brake caliper body 401.

[0057] The present invention has the following beneficial effects:

[0058] A two-stage planetary gear transmission pair is adopted in series, and a first friction pad 204 and a second friction pad 211 are respectively arranged on the end faces of the input gear shaft 203 and the reducer output shaft 210 facing each other, so as to isolate the input gear shaft 203 from the sun gear 207 and the sun gear 207 from the reducer output shaft 210, so as to avoid impact during operation and reduce noise; and reduce the friction area with the sun gear 207, reduce the friction coefficient, thereby reducing friction loss and further reducing noise; an anti-rotation buffer structure is arranged on the inner gear ring 201 to reduce the impact on the gear mechanism during starting, reversing and stopping; a vibration-damping buffer structure is arranged on the return position of the nut 302 of the ball screw pair 300 to reduce impact and noise; the ball screw 301 and the reducer output shaft 210 are connected by axial pre-tightening to eliminate axial play clearance, improve the assembly accuracy of the system, and reduce the risk of vibration damage to parts caused by external vibration; the overall structure is compact and easy to assemble and maintain.

[0059] In the description of the present invention, it is necessary to understand that the terms "center", "length", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "inside", "outside", "peripheral", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred system or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0060] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0061] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A transmission device for a vehicle brake system, comprising a motor assembly (100), a gear reducer (200), a ball screw pair (300), a brake caliper body (401), a first brake friction block (402) and a brake disc (403), wherein the ball screw pair (300) is arranged on the inner side of the brake caliper body (401), the output shaft of the motor assembly (100) is transmission-connected to the input gear shaft (203) of the gear reducer (200), the output shaft of the gear reducer (200) is transmission-connected to the first brake friction block (402) through the ball screw pair (300) to drive the first brake friction block (402) to approach the brake disc (403), characterized in that: The gear reducer (200) comprises an input gear shaft (203), a primary planetary gear transmission pair, a sun gear (207), a secondary planetary gear transmission pair and a reducer output shaft (210), wherein the input gear shaft (203) is drivingly connected to the output shaft of the motor assembly (100), the input gear shaft (203) is drivingly connected to the input end of the primary planetary gear transmission pair, the output end of the primary planetary gear transmission pair is drivingly connected to the sun gear (207), and the sun gear (207) is drivingly connected to the input end of the secondary planetary gear transmission pair. The output end of the secondary planetary gear transmission pair is transmission-connected to the reducer output shaft (210), and the reducer output shaft (210) is transmission-connected to the ball screw pair (300). The input gear shaft (203), the sun gear (207) and the reducer output shaft (210) are coaxially arranged, and a first friction pad (204) is arranged at one end of the input gear shaft (203) facing the sun gear (207), and a second friction pad (211) is arranged at one end of the reducer output shaft (210) coaxially facing the sun gear (207).

2. A transmission device for a vehicle braking system according to claim 1, characterized in that: The motor assembly (100) comprises a motor housing (101), a motor rotor (102) and a motor stator (103); the motor stator (103) is fixedly arranged in the motor housing (101); the motor rotor (102) is rotatably arranged inside the motor stator (103); an axial hole is arranged in the motor rotor (102); the input gear shaft (203) is coaxially arranged with the axial hole, and one end of the input gear shaft (203) is fixedly arranged in the axial hole.

3. A transmission device for a vehicle braking system according to claim 2, characterized in that: The first-stage planetary gear transmission pair comprises an inner gear ring (201), a planetary disc (202) and a first-stage planetary wheel (206); the inner gear ring (201) is arranged in the shaft hole; the planetary disc (202) is rotatably arranged in the inner gear ring (201); the planetary disc (202) is coaxially arranged with the inner gear ring (201); one end of the sun gear (207) is coaxially fixedly connected with the planetary disc (202); a plurality of first cylindrical pins (205) are arranged on a side of the planetary disc (202) facing the input gear shaft (203); the first-stage planetary wheel (206) is rotatably sleeved on the first cylindrical pin (205); the first-stage planetary wheel (206) is meshed with the inner gear ring (201); and the other end of the input gear shaft (203) is meshed with the plurality of first-stage planetary wheels (206).

4. A transmission device for a vehicle braking system according to claim 3, characterized in that: An inner gear ring flange is fixedly provided on one end of the inner gear ring (201) facing the brake caliper body (401), and a plurality of third cylindrical pins (212) are fixedly provided on the inner gear ring flange. The brake caliper body (401) is provided with pin holes (410) corresponding to the third cylindrical pins (212) one by one, and a step hole is provided at the opening of the pin hole (410), and a vibration damping ring (9) is embedded in the step hole. One end of the third cylindrical pin (212) away from the inner gear ring flange passes through the vibration damping ring (9) and is inserted into the pin hole (410).

5. A transmission device for a vehicle braking system according to claim 3, characterized in that: The secondary planetary gear transmission pair comprises a secondary planetary gear (209); an output shaft flange is fixedly provided on one end of the reducer output shaft (210) facing the sun gear (207); a plurality of second cylindrical pins (208) are fixedly provided on the side of the output shaft flange facing the sun gear (207); the secondary planetary gear (209) is rotatably provided on the second cylindrical pins (208); and the secondary planetary gear (209) is meshed with the sun gear (207) and the inner gear ring (201).

6. A transmission device for a vehicle braking system according to claim 5, characterized in that: A flat gasket (8) is provided between the side of the output shaft flange away from the sun gear (207) and the brake caliper body (401).

7. A transmission device for a vehicle braking system according to claim 1, characterized in that: A sliding bearing (7) is provided in the center hole of the brake caliper body (401), the reducer output shaft (210) is inserted into the sliding bearing (7), the screw (301) of the ball screw pair (300) is connected to the reducer output shaft (210) at one end away from the sun gear (207) via a spline, and the nut (302) of the ball screw pair (300) is connected to the first brake friction member at one end away from the sun gear (207). The wiper block (402) is in axial contact, and a mounting hole (414) is provided on the brake caliper body (401). The mounting hole (414) is arranged opposite to one end of the nut (302) of the ball screw pair (300) facing the sun gear (207). A vibration damping pad (10) is provided in the mounting hole (414), and the vibration damping pad (10) protrudes out of the mounting hole (414) at one end of the nut (302) of the ball screw pair (300).

8. A transmission device for a vehicle braking system according to claim 7, characterized in that: One end of the mounting hole (414) away from the nut (302) of the ball screw pair (300) is a V-shaped countersunk hole (411), and one end of the vibration damping pad (10) away from the nut (302) of the ball screw pair (300) is a frustum-shaped structure matching the V-shaped countersunk hole (411).

9. A transmission device for a vehicle braking system according to claim 7, characterized in that: A locking nut (5) is threadedly connected to one end of the reducer output shaft (210) away from the sun gear (207); an inner ring platform (303) is arranged on the inner side of the screw (301) of the ball screw pair (300); the inner ring platform (303) is connected to the reducer output shaft (210) via a spline; a ring groove (13) is arranged on the side of the locking nut (5) facing the inner ring platform (303); a wave spring (4) is arranged between the ring groove (13) and the side wall of the inner ring platform (303); a plane thrust bearing (2) and a force sensor (1) are arranged in sequence between the other side of the inner ring platform (303) and the inner wall of the brake caliper body (401).

10. A transmission device for a vehicle brake system according to any one of claims 1 to 9, characterized in that: An input shaft countersunk hole (213) is provided at one end of the input gear shaft (203) facing the sun gear (207), and one end of the first friction pad (204) is embedded in the input shaft countersunk hole (213); an output shaft countersunk hole (214) is provided at one end of the reducer output shaft (210) coaxially facing the sun gear (207), and one end of the second friction pad (211) is embedded in the output shaft countersunk hole (214).

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