Brake and multi-piston driving device

Abstract

The utility model relates to a multi-piston driving device of a friction brake, piston rods in a plurality of pistons are driven by a screw to move in the axial direction, and the multi-piston driving device is characterized in that the piston rods driven by the screw are respectively stopped by a rotation stopping mechanism. According to the utility model, the following rotation problem of the spiral transmission type piston rod is solved, so that the synchronism among multiple pistons is improved.

Description

Technical Field

[0001] This utility model relates to brakes and multi-piston drive devices. Background Technology

[0002] In a car's braking system, the brakes play a crucial role, and their performance directly affects the car's driving safety.

[0003] A significant problem in brake pistons driven by helical transmission is the tendency for the piston rod to rotate along with the piston. Some of the rotational motion is not converted into axial motion, resulting in stroke loss. This loss is particularly problematic in multi-piston brakes, where it also leads to asynchrony between pistons. This results in decreased braking stability, reduced passenger comfort, and compromised driving safety. Utility Model Content

[0004] The main purpose of this invention is to solve the synchronization problem between pistons driven by a helical mechanism, thereby providing a multi-piston drive device for a brake with good synchronization.

[0005] To achieve the above objectives, this utility model provides a multi-piston drive device for a friction brake, wherein the piston rods of the multiple pistons move axially under helical transmission, and the piston rods under helical transmission are respectively stopped by anti-rotation mechanisms.

[0006] In some embodiments of this utility model, the motor drives multiple piston rods via a transmission mechanism.

[0007] In some embodiments of this utility model, a motor output gear is provided on the output shaft of the motor. The motor output gear meshes with an intermediate gear, which meshes with multiple planetary gear systems. The planetary gear systems coaxially drive a helical drive shaft, and each helical drive shaft helically drives the piston rod of each piston.

[0008] In some embodiments of this utility model, the piston rod has an internal threaded hole, the helical drive shaft has an external threaded circumferential surface, and the helical drive shaft and the piston rod achieve helical transmission through the threaded engagement of the internal threaded hole and the external threaded circumferential surface.

[0009] In some embodiments of this utility model, the anti-rotation mechanism includes a limiting protrusion disposed on the inner side of the piston cavity and a limiting recess disposed on the outer surface of the piston rod. The limiting recess extends along the axial direction, and the limiting protrusion and the limiting recess are in a convex-concave fit. The limiting protrusion can slide relative to the limiting recess in the axial direction and prevent the limiting recess from rotating in the rotation direction.

[0010] In some embodiments of this utility model, the concave-convex fit is independently selected from wedge fit, dovetail fit, trapezoidal fit, spherical surface fit or rectangular fit.

[0011] In some embodiments of this utility model, the anti-rotation screw is fixed and protrudes from the inner side of the piston cavity to form the limiting protrusion.

[0012] In some embodiments of this invention, two pistons are included, and the piston rods of both pistons are driven by the helical mechanism.

[0013] In some embodiments of this invention, the front end of the piston rod has a friction plate mounting portion.

[0014] In some embodiments of this invention, a force sensor is provided at the rear end of one of the piston rods.

[0015] The second aspect of this invention relates to a brake, which includes any of the aforementioned multi-piston drive devices.

[0016] This invention solves the problem of the piston rod rotating in a helical drive system, thereby improving the synchronization between multiple pistons. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a multi-piston drive device.

[0018] Figure 2 for Figure 1 A partial sectional view.

[0019] Figure 3 This is a specific structural diagram of a stop-rotation mechanism.

[0020] Figure 4 for Figure 3 A cross-sectional schematic diagram.

[0021] In the diagram: 110 - Motor output gear, 120 - Intermediate gear, 130 - First planetary gear train, 140 - Second planetary gear train, 141 - Second sun gear, 142 - Second internal gear ring, 143 - Second planetary gear, 144 - Second planetary carrier, 150 - Force sensor, 210 - First piston, 220 - Second piston, 221 - Second piston rod, 222 - Second helical drive shaft, 2221 - Spline, 223 - Second piston cavity, 311 - First anti-rotation bolt, 321 - Second anti-rotation bolt, 322 - Second groove, 410 - Inner friction plate, 420 - Outer friction plate. Detailed Implementation

[0022] In some existing brake structures, the brake uses multiple pistons to drive friction pads to perform braking and releasing actions. These pistons are driven by the same motor, with the piston rods moving axially via a helical drive. After a period of operation, this type of friction brake experiences a loss of synchronization among the pistons, meaning that the axial positions of the piston rods differ at any given moment. This invention reveals that when the piston rods are driven by the helical drive, they sometimes rotate in tandem, losing part of their stroke and ultimately leading to asynchrony among the multiple piston rods.

[0023] This invention addresses the aforementioned problems by improving the multi-piston drive device of the friction brake based on the existing structure, aiming to enhance the synchronization between pistons. The improvement mainly includes: each piston rod subjected to helical drive is prevented from rotating by an anti-rotation mechanism. By setting the anti-rotation mechanism, the piston rods are prevented from rotating along with the helical drive, thus ensuring that the helical drive of each piston rod can be fully converted into linear motion.

[0024] The aforementioned anti-rotation structure can be any structure capable of preventing the piston rod from rotating. One specific structure of the anti-rotation mechanism includes a limiting protrusion disposed on the inner side of the piston cavity and a limiting recess disposed on the outer surface of the piston rod. The limiting recess extends along the axial direction, and the limiting protrusion and the limiting recess engage in a convex-concave fit. The limiting protrusion can slide relative to the limiting recess axially and prevents the limiting recess from rotating in the rotational direction. Furthermore, the convex-concave fit of the anti-rotation mechanism for each piston rod can be independently selected from wedge fit, dovetail fit, trapezoidal fit, spherical surface fit, rectangular fit, or other similar fit methods. See Appendix [for example]. Figures 1 to 3 A first anti-rotation structure and a second anti-rotation mechanism are provided on the piston chambers of the first piston 210 and the second piston 220. Taking the second anti-rotation mechanism as an example, it is used to prevent the second piston rod from rotating 221. The second anti-rotation mechanism includes a second anti-rotation bolt 321 and a second groove 322. The second anti-rotation bolt 321 is fixed and protrudes from the inner side of the second piston chamber 223 to form a second limiting protrusion. A second groove 322 extending axially is provided on the outer side of the second piston rod 221. The second anti-rotation bolt 321 and the second groove 322 cooperate to achieve anti-rotation and limiting. When the second piston rod 221 is subjected to helical transmission, the second anti-rotation bolt 321 and the second groove 322 move relative to each other axially to limit the second piston rod 221 to move only in the axial direction and prevent the second piston rod 221 from rotating.

[0025] The first and second planetary gear trains can adopt known planetary gear train structures. Their main functions include, but are not limited to, transmitting torque, configuring gear ratios, increasing braking torque, and achieving differential functionality.

[0026] Figures 1-4 A multi-piston drive device for a friction brake is shown. It includes a first piston 210 and a second piston 220. The front ends of the first piston rod of the first piston 210 and the second piston rod of the second piston 220 are connected to an inner friction plate 410, thereby driving the inner friction plate 410 to move closer to or further away from the outer friction plate 420 to perform braking or releasing the braking action.

[0027] In this multi-piston drive device, a single motor drives the piston rods of the two pistons axially via a transmission mechanism. (See also...) Figure 1 and Figure 2 A motor output gear 110 mounted on the motor output shaft meshes with an intermediate gear 120. The intermediate gear 120 meshes with a first planetary gear train 130 and a second planetary gear train 140. The first planetary gear train 130 and the second planetary gear train 140 coaxially drive a first helical drive shaft and a second helical drive shaft, respectively. The first helical drive shaft and the second helical drive shaft helically drive the first piston rod in the first piston 210 and the second piston rod in the second piston 220, respectively. The first planetary gear train 130 and the second planetary gear train 140 have the same structure. (Refer to...) Figure 1 and 2 Taking the second planetary gear system 140 as an example, it includes a second sun gear 141, a second internal gear ring 142, multiple second planet gears 143, and a second planet carrier 144. The intermediate gear 120 meshes with the second sun gear 141 for transmission. The second sun gear 141 meshes with the multiple second planet gears 143, causing them to rotate in the second internal gear ring 142 and drive the second planet carrier 144 to rotate. The second planet carrier 144 and the second helical drive shaft 222 are connected by a spline 2221 (…). Figure 3 Assembly enables coaxial transmission. (Reference) Figure 2 The second piston rod 221 has an internal threaded hole, and the second helical drive shaft 222 has an external threaded circumferential surface. The second helical drive shaft 222 and the second piston rod 221 achieve helical transmission through the threaded engagement of the internal threaded hole and the external threaded circumferential surface, so that the second piston rod 221 moves axially in the second piston cavity 223. Similarly, the first planetary gear system includes a first sun gear, a first internal gear ring, multiple first planet gears, and a first planet carrier. The intermediate gear meshes with the first sun gear for transmission. The first sun gear meshes with the multiple first planet gears to rotate in the first internal gear ring and drive the first planet carrier to rotate. The first planet carrier and the first helical drive shaft achieve coaxial transmission through spline assembly. (Reference) Figure 2 The first piston rod has an internal threaded hole, and the first helical drive shaft has an external threaded circumferential surface. The first helical drive shaft and the first piston rod achieve helical transmission through the threaded engagement of the internal threaded hole and the external threaded circumferential surface, so that the first piston rod moves axially in the first piston cavity.

[0028] A force sensor 150 is also provided between the bottom of the second piston chamber 223 and the second piston rod 221. This structure is known and will not be described in detail here.

[0029] A first anti-rotation structure and a second anti-rotation mechanism are provided on the piston chambers of the first piston 210 and the second piston 220. The first anti-rotation structure and the second anti-rotation mechanism have the same structure. Taking the second anti-rotation mechanism as an example, the second anti-rotation mechanism includes a second anti-rotation bolt 321 and a second groove 322. The second anti-rotation bolt 321 is fixed and protrudes from the inner side of the second piston chamber 223 to form the second limiting protrusion. A second groove 322 extending axially is provided on the outer side of the second piston rod 221. The second anti-rotation bolt 321 and the second groove 322 cooperate to achieve anti-rotation and limiting. Similarly, the first anti-rotation mechanism includes a first anti-rotation bolt and a first groove. The first anti-rotation bolt is fixed and protrudes from the inner side of the first piston chamber to form the first limiting protrusion. A first groove extending axially is provided on the outer side of the first piston rod. The first anti-rotation bolt and the first groove cooperate to achieve anti-rotation and limiting.

[0030] Therefore, when the motor starts working, the first and second piston rods move axially under helical transmission. The first and second anti-rotation screws move relative to the first and second grooves axially to restrict the first and second piston rods to move only in the axial direction and prevent them from rotating in tandem. This avoids loss of axial travel and ensures the synchronicity of the axial positions of the first and second piston rods.

[0031] The embodiments described in this utility model are for illustrative purposes only and do not constitute a limitation on the scope of the claims. Other substantially equivalent substitutions that can be conceived by those skilled in the art are all within the protection scope of this utility model.

Claims

1. A multi-piston drive device for a brake, wherein the piston rod of the multiple pistons moves axially under helical transmission, characterized in that... The piston rods driven by the screw are respectively prevented from rotating by anti-rotation mechanisms. The anti-rotation mechanism includes a limiting protrusion disposed on the inner side of the piston cavity and a limiting recess disposed on the outer surface of the piston rod. The limiting recess extends along the axial direction, and the limiting protrusion and the limiting recess are in a convex-concave fit. The limiting protrusion can slide relative to the limiting recess in the axial direction and prevent the limiting recess from rotating in the rotation direction.

2. The multi-piston drive device as described in claim 1, characterized in that... The motor drives multiple piston rods via a transmission mechanism.

3. The multi-piston drive device as described in claim 2, characterized in that... The motor output shaft is equipped with a motor output gear, which meshes with an intermediate gear, which in turn meshes with multiple planetary gear trains, which coaxially drive a helical drive shaft. Each helical drive shaft then helically drives the piston rod of its respective piston.

4. The multi-piston drive device as described in claim 3, characterized in that... The piston rod has an internal threaded hole, and the helical drive shaft has an external threaded circumferential surface. The helical drive shaft and the piston rod achieve helical transmission through the threaded engagement of the internal threaded hole and the external threaded circumferential surface.

5. The multi-piston drive device as described in claim 1, characterized in that... The concave-convex fits are independently selected from wedge fits, dovetail fits, trapezoidal fits, spherical surface fits, or rectangular fits.

6. The multi-piston drive device as described in claim 1, characterized in that... The anti-rotation screw is fixed and protrudes from the inner side of the piston cavity to form the limiting protrusion.

7. The multi-piston drive device as described in claim 1, characterized in that... It includes two pistons, and the piston rods of both pistons are driven by a helical mechanism.

8. The multi-piston drive device as described in claim 1, characterized in that... The piston rod has a friction plate mounting section at its front end.

9. The multi-piston drive device as described in claim 1, characterized in that... A force sensor is installed at the rear end of one of the piston rods.

10. A brake, characterized in that, Includes the multi-piston drive device according to any one of claims 1 to 9.

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