Hand brake assembly and all-terrain vehicle using same

Abstract

The invention discloses a hand brake assembly and an all-terrain vehicle using the hand brake assembly. The hand brake assembly comprises a pump body, a control handle, a piston and an elastic piece, and the control handle is installed on the pump body; the piston is connected with a control handle; the elastic piece abuts against the piston. The hand brake assembly further comprises a sealing assembly, and the sealing assembly is fixed to the pump body and arranged on the outer edge of the piston in a sleeving mode. The pump body is provided with a first cavity, a second cavity communicated with the first cavity and an oil outlet communicated with the second cavity, the first cavity is used for storing oil, and the piston is arranged in the second cavity and can axially move in the second cavity; one end of the piston is connected with the control handle, and the elastic piece abuts against the piston. A compensation hole is formed in the piston, when the control handle is in an initial state, the compensation hole is communicated with the first cavity, and when the control handle is in a braking state, the compensation hole is blocked by the sealing assembly. Through the arrangement, the impact resistance of the hand brake assembly is improved, and the hand brake assembly is prevented from being damaged by hydraulic pulse force when the ABS control module works.

Description

Technical Field

[0001] The present application relates to the field of vehicle engineering, and particularly to a handbrake assembly and an all-terrain vehicle using the handbrake assembly. Background Art

[0002] In the related art, a compensation hole of the handbrake assembly is opened on the pump body, a piston is arranged in a chamber formed by the pump body, and a sealing member is sleeved on the outer edge of the piston and can move along with the piston. When the piston moves, the outer edge of the sealing member blocks the compensation hole to prevent the hydraulic pulse force generated by the ABS control module from flushing back into the chamber of the pump body.

[0003] When the ABS control module is triggered, the control handle will switch to the initial state due to the action of the hydraulic pulse force generated by the ABS control module. When the hydraulic pulse force becomes smaller, if the user keeps pressing the control handle, the control handle will switch from the initial state to the braking state again, which may trigger the ABS control module again, forming a continuous and periodic state switch. During the process of the control handle switching from the initial state to the braking state, the piston is impacted by the hydraulic pulse force and moves, and the sealing member also moves accordingly until the sealing member does not completely block the compensation hole to complete pressure relief. During this process, the sealing member and the pump body are worn, and the impact resistance of the handbrake assembly is relatively low, resulting in damage to the handbrake assembly by the hydraulic pulse force when the ABS control module is working. Summary of the Invention

[0004] In order to solve the deficiencies of the prior art, the purpose of the present application is to provide a handbrake assembly and an all-terrain vehicle using the handbrake assembly, and the handbrake assembly has relatively high impact resistance and can avoid damage to the handbrake assembly by the hydraulic pulse force when the ABS control module is working.

[0005] To achieve the above purpose, the present application adopts the following technical solutions: In the first aspect, the present application provides a handbrake assembly, which includes a pump body, a control handle, a piston and an elastic member. The control handle is installed on the pump body and can rotate relative to the pump body; the piston is arranged in the pump body and is connected to the control handle; the elastic member is arranged in the pump body and abuts against the piston; the handbrake assembly further includes a sealing assembly, the sealing assembly is fixed to the pump body and sleeved on the outer edge of the piston; the pump body has a first chamber, a second chamber communicating with the first chamber, and an oil outlet communicating with the second chamber. The first chamber is used for storing oil, the piston is arranged in the second chamber and can axially move in the second chamber; one end of the piston is connected to the control handle, and the elastic member is located between the other end of the piston and the oil outlet and abuts against the piston; a compensation hole is opened on the piston. When the control handle is in the initial state, the compensation hole communicates with the first chamber, and when the control handle is in the braking state, the compensation hole is blocked by the sealing assembly.

[0006] Further, an installation groove is formed in the pump body. The installation groove is used for installing the sealing assembly and axially limiting the sealing assembly.

[0007] Further, an oil delivery hole is formed between the first chamber and the second chamber. The sealing assembly includes a first seal and a second seal. When observed radially from the piston, the first seal and the second seal are respectively arranged on both sides of the oil delivery hole, and the second seal is located between the first seal and the oil outlet.

[0008] Further, when the control handle is in the braking state, the compensation hole is covered by the second seal.

[0009] Further, a liquid storage chamber is formed at one end of the piston that abuts against the elastic member. The liquid storage chamber communicates with the second chamber. The piston includes side walls circumferentially distributed around the liquid storage chamber. The compensation hole is located on the side wall and is distributed around the liquid storage chamber.

[0010] Further, the handbrake assembly further includes a limit pin. The limit pin is arranged in the liquid storage chamber and extends along a preset direction. The limit pin is used to limit the compression direction of the elastic member, and the compression direction coincides with the preset direction.

[0011] Further, a fixing groove is also formed in the pump body. The fixing groove is arranged around the oil outlet. A convex portion is provided on the outer edge of the limit pin. One end of the elastic member is arranged in the fixing groove, and the other end of the elastic member abuts against the convex portion.

[0012] Further, an annular groove communicating with the oil delivery hole is formed on the inner wall of the pump body. The inner diameter of the annular groove is larger than the outer diameter of the piston. The cross-section of the annular groove is trapezoidal, wherein the cross-section of the annular groove is parallel to the axis of the piston.

[0013] Further, the handbrake assembly further includes a piston push rod, a dust cover and a retaining ring. The two ends of the piston push rod are respectively abutted against the control handle and the piston. The dust cover circumferentially covers at least part of the piston push rod. The retaining ring is arranged between the dust cover and the piston. The dust cover and the retaining ring jointly seal the second chamber.

[0014] In a second aspect, the present application further provides an all-terrain vehicle, including a running system and a braking system. The running system includes a front wheel and a rear wheel; the braking system includes a brake pedal, a brake pump and an ABS control module. The brake pedal transmits the braking pressure to the ABS control module through the brake pump and distributes the braking pressure to the front wheel and / or the rear wheel according to the ABS control module; the braking system further includes the above-mentioned handbrake assembly.

[0015] The handbrake assembly provided by this application fixes the sealing component to the pump body and opens the compensation hole in the piston. During the movement of the piston, the wear of the sealing component is relatively small. Compared with the related art, in this application, the sealing component is fixed to the pump body, making the handbrake assembly have higher impact resistance and being able to avoid damage to the handbrake assembly by hydraulic pulse force when the ABS control module is working. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of an all-terrain vehicle in an embodiment of this application; Figure 2 Control logic diagram of the ABS control module in an embodiment of this application; Figure 3 Exploded view of the handbrake assembly in an embodiment of this application; Figure 4 Cross-sectional view of the handbrake assembly in an embodiment of this application; Figure 5 is Figure 4 enlarged view of part A in Figure 6 Schematic diagram of a handbrake assembly using a cylindrical spring in an embodiment of this application. SPECIFIC EMBODIMENTS

[0017] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the specific embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application.

[0018] It should be noted that the "first", "second" and similar terms used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not indicate a quantity limitation, but indicate that there is at least one. "Multiple" or "several" means at least two. "Including" means that the elements or objects appearing before "including" cover the elements or objects listed after "including" and their equivalents, and do not exclude other elements or objects. "Connect" or "be connected" and similar terms are not limited to physical or mechanical connections, whether direct or indirect.

[0019] Such as Figure 1 and Figure 2As shown in the figure, the present application provides an all-terrain vehicle 100, which includes a frame 10, a suspension system 20, a running system 30, and a braking system 40. The frame 10 constitutes the main frame of the all-terrain vehicle 100. The running system 30 is located below the frame 10 and is used to support the frame 10. The suspension system 20 can transmit the force and torque between the frame 10 and the running system 30. The running system 30 includes a front wheel 31 and a rear wheel 32. The front wheel 31 is connected to the front part of the frame 10 through at least part of the suspension system 20, and the rear wheel 32 is connected to the rear part of the frame 10 through at least part of the suspension system 20. The braking system 40 includes a brake pedal 41, a brake pump 42, and an ABS (Anti-Lock Braking System) control module 43. The brake pedal 41 transmits the braking pressure to the ABS control module 43 through the brake pump 42, and distributes the braking pressure to the front wheel 31 and / or the rear wheel 32 according to the ABS control module 43 to realize the braking of the all-terrain vehicle 100 on the premise of ensuring the handling stability.

[0020] As Figure 2 and Figure 3 shown in the figure, the braking system 40 further includes a handbrake assembly 44. The handbrake assembly 44 can generate braking pressure and transmit the braking pressure to the ABS control module 43 through the brake pump 42. After receiving the braking pressure, the ABS control module 43 distributes the braking pressure to the front wheel 31 to realize the braking of the front wheel 31. The handbrake assembly 44 includes a pump body 441, a control handle 442, a piston 443, and an elastic member 444. The control handle 442 is installed on the pump body 441 and can rotate relative to the pump body 441. The piston 443 is located in the pump body 441 and is connected to the elastic member 444.

[0021] As Figure 3 and Figure 4 shown in the figure, as an implementation manner, the pump body 441 has a first chamber 4411, a second chamber 4412, and an oil outlet 4413. The first chamber 4411 is used to store oil, and the first chamber 4411 is communicated with the second chamber 4412, so that the oil can enter the second chamber 4412 from the first chamber 4411 or enter the first chamber 4411 from the second chamber 4412 according to the change of the pressure in the second chamber 4412. The second chamber 4412 is communicated with the oil outlet 4413, so that the oil in the second chamber 4412 can flow out of the second chamber 4412 through the oil outlet 4413 and flow into the brake pump 42.

[0022] The handbrake assembly 44 further includes a sealing assembly 445. The sealing assembly 445 is sleeved on the outer edge of the piston 443 and fixed to the pump body 441. The piston 443 is arranged in the second chamber 4412 and can axially move in the second chamber 4412. The piston 443 has a first end 4431 and a second end 4432. The first end 4431 of the piston 443 is connected to the control handle 442, and the second end 4432 of the piston 443 abuts against the elastic member 444. The elastic member 444 is located between the second end 4432 of the piston 443 and the oil outlet 4413.

[0023] It should be noted that since the inner wall of the pump body 441 is formed by injection molding, the flatness of the inner wall of the pump body 441 is lower. Fixing the sealing assembly 445 to the pump body 441 can avoid mutual friction between the sealing assembly 445 and the inner wall of the pump body 441 when the piston 443 moves in the second chamber 4412, thereby extending the service life of the sealing assembly 445.

[0024] A compensation hole 4433 is formed in the piston 443. When the control handle 442 is in the initial state, the compensation hole 4433 communicates with the first chamber 4411. When the control handle 442 is in the braking state, the compensation hole 4433 is blocked by the sealing assembly 445.

[0025] It should be noted that the initial state of the control handle 442 means that the control handle is in a non-braking state, that is, the control handle 442 does not brake the all-terrain vehicle 100.

[0026] To clearly illustrate the technical solution of the present application, the part from the second end 4432 of the piston 443 to the oil outlet 4413 in the second chamber 4412 is defined as the pressure chamber 4412a. When the control handle 442 is in the initial state, the pressure chamber 4412a communicates with the first chamber 4411 through the compensation hole 4433. When the control handle 442 is in the braking state, the compensation hole 4433 is blocked by the sealing assembly 445, and the pressure chamber 4412a is not communicated with the first chamber 4411.

[0027] Specifically, when the control handle 442 is in the braking state, the control handle 442 applies a force to the piston 443. The piston 443 moves in the direction towards the elastic member 444 under the action of the force of the control handle 442 and applies a pressure to the elastic member 444. At this time, the elastic member 444 is compressed. When the piston 443 moves to the position where the compensation hole 4433 is blocked by the sealing assembly 445, the pressure chamber 4412a is not communicated with the first chamber 4411, and the oil fluid cannot flow between the pressure chamber 4412a and the first chamber 4411 through the compensation hole 4433. The oil fluid flows to the brake pump 42 through the oil outlet 4413.

[0028] Since the elastic member 444 is compressed and stores a certain amount of elastic potential energy, if the control handle 442 is changed from the braking state to the initial state at this time, the acting force exerted by the control handle 442 on the piston 443 disappears, and the elastic potential energy of the elastic member 444 will be converted into kinetic energy, thereby driving the piston 443 to move in a direction away from the elastic member 444. Until the compensation hole 4433 is not blocked by the sealing assembly 445, the pressure chamber 4412a communicates with the first chamber 4411, and the hydraulic oil can flow from the pressure chamber 4412a into the first chamber 4411 through the compensation hole 4433 to balance the pressure in the pressure chamber 4412a, and the hydraulic oil in the brake pump 42 flows back to the pressure chamber 4412a through the oil outlet 4413.

[0029] Further, when the control handle 442 is in the braking state, if a risk of wheel lock-up is detected, the ABS control module 43 is triggered to intervene. The ABS control module 43 generates a hydraulic pulse force, and the hydraulic oil flows from the brake pump 42 into the pressure chamber 4412a through the oil outlet 4413, causing the pressure in the pressure chamber 4412a to increase instantaneously, thereby driving the piston 443 to move in a direction away from the elastic member 444, so that the control handle 442 has a tendency to switch from the braking state to the initial state under the action of the piston 443. When the control handle 442 is switched from the braking state to the initial state, the sealing assembly 445 no longer blocks the compensation hole 4433, and the hydraulic oil flows from the pressure chamber 4412a into the first chamber 4411, realizing the pressure relief of the pressure chamber 4412a.

[0030] With the above settings, if the ABS control module 43 is triggered, the piston 443 moves in a direction away from the elastic member 444, causing the hydraulic oil to enter the first chamber 4411 through the compensation hole 4433. The sealing assembly 445 and the pump body 441 remain stationary, which can reduce the wear of the sealing assembly 445, improve the impact resistance of the handbrake assembly 44, and prevent the handbrake assembly 44 from being damaged by the hydraulic pulse force when the ABS control module 43 is working.

[0031] As an implementation method, a plurality of installation grooves 4414 for installing the sealing assembly 445 are provided on the inner wall of the pump body 441. The installation grooves 4414 are arranged circumferentially around the piston 443. The sealing assembly 445 is sleeved on the outer edge of the piston 443 and installed in the installation grooves 4414. When the piston 443 moves in the second chamber 4412, the installation grooves 4414 limit the movement of the sealing assembly 445 along the axial direction of the piston 443, so that the sealing assembly 445 and the pump body 441 remain relatively stationary.

[0032] In some embodiments, the material of the sealing assembly 445 includes but is not limited to rubber, polytetrafluoroethylene, polyurethane, etc.

[0033] In some embodiments, the sealing assembly 445 can be a leather cup. During the operation of the handbrake assembly 44, the root of the leather cup contacts the compensation hole 4433. The root of the leather cup has better anti-wear and anti-impact capabilities compared to the lip of the leather cup. And since the root of the leather cup contacts the outer surface of the piston 443, and the outer surface of the piston 443 is relatively smooth, even if the piston 443 rubs against the root of the leather cup during movement, the wear of the root of the leather cup is small, enabling the leather cup to bear the pressure in the pressure chamber 4412a when the operating handle 442 is in the braking state.

[0034] In an embodiment of the present application, the handbrake assembly 44 further includes a piston push rod 446, a dust cover 447, and a retaining ring 448. One end of the piston push rod 446 is connected to the operating handle 442, and the other end of the piston push rod 446 is connected to the first end 4431 of the piston 443, so that the piston push rod 446 can transmit the acting force on the operating handle 442 to the first end 4431 of the piston 443, thereby pushing the piston 443 to move in the direction close to the elastic member 444. The dust cover 447 circumferentially covers at least a part of the piston push rod 446, and the retaining ring 448 is disposed between the dust cover 447 and the piston 443. The dust cover 447 and the retaining ring 448 jointly seal the second chamber 4412.

[0035] As Figure 4 and Figure 5 shown, as an implementation, an oil delivery hole 4415 is provided between the first chamber 4411 and the second chamber 4412. One end of the oil delivery hole 4415 communicates with the first chamber 4411, and the other end of the oil delivery hole 4415 communicates with the second chamber 4412. The sealing assembly 445 includes a first seal 4451 and a second seal 4452. When viewed radially from the piston 443, the first seal 4451 and the second seal 4452 are respectively arranged on both sides of the oil delivery hole 4415, and the second seal 4452 is located between the first seal 4451 and the oil outlet 4413. The first seal 4451 and the second seal 4452 can block the gap between the piston 443 and the pump body 441. The first seal 4451 seals the oil from the side of the first seal 4451 close to the oil outlet 4413, and the second seal 4452 seals the oil from the side of the second seal 4452 away from the oil outlet 4413. When the operating handle 442 is in the braking state, the second seal 4452 blocks the compensation hole 4433.

[0036] Specifically, when the control handle 442 is in the braking state, the compensation hole 4433 is blocked by the second seal 4452, that is, the second seal 4452 seals the pressure chamber 4412a. If the pressure at the oil outlet 4413 is the same as the pressure in the pressure chamber 4412a, at this time, the second seal 4452 can prevent the oil in the pressure chamber 4412a from entering the first chamber 4411 through the compensation hole 4433 and the oil delivery hole 4415, realizing pressure build-up from the pressure chamber 4412a to the oil outlet 4413.

[0037] Furthermore, when the control handle 442 is in the braking state, the compensation hole 4433 is blocked by the second seal 4452. If the ABS control module 43 is triggered at this time, the control handle 442 will switch to the initial state under the action of the hydraulic pulse force generated by the ABS control module 43. If the user keeps pressing the control handle 442, when the hydraulic pulse force becomes smaller, the control handle 442 will switch from the initial state to the braking state again, forming a continuous and periodic state switch. During the process of the control handle 442 switching from the braking state to the initial state, the oil is compressed from the brake pump 42 towards the oil outlet 4413, making the pressure at the oil outlet 4413 greater than the pressure in the pressure chamber 4412a. The high-pressure oil will force the piston 443 to move away from the elastic member 444 until the oil can flow into the first chamber 4411 through the compensation hole 4433, realizing the pressure relief of the pressure chamber 4412a.

[0038] In the embodiment of the present application, both the first seal 4451 and the second seal 4452 are set as "C"-type leather cups. It should be noted that the first seal 4451 and the second seal 4452 can be set as any combination of "C"-type leather cups and "E"-type leather cups.

[0039] Through the above settings, any combination of the first seal 4451 and the second seal 4452 is used to seal the gap between the piston 443 and the pump body 441, improving the tightness of the handbrake assembly 44.

[0040] Such as Figure 4 and Figure 5As shown, as an implementation, a liquid storage cavity 4434 is formed at the second end 4432. When observed axially from the piston 443, the liquid storage cavity 4434 communicates with the pressure cavity 4412a. The piston 443 includes a side wall 4436 circumferentially distributed around the liquid storage cavity 4434. The compensation holes 4433 are located on the side wall 4436. The piston 443 has a plurality of compensation holes 4433. The plurality of compensation holes 4433 are circumferentially spaced apart on the side wall 4436 of the piston 443 along the circumferential direction of the piston 443 and are distributed around the liquid storage cavity 4434. The hydraulic oil can enter the liquid storage cavity 4434 through the pressure cavity 4412a and enter the first chamber 4411 through the compensation holes 4433. The compensation holes 4433 distributed around the liquid storage cavity 4434 can improve the pressure transmission efficiency, reduce the time for the operating handle 442 to receive feedback after the ABS control module 43 is triggered, and at the same time make the stress distribution more uniform, avoiding the reduction of the strength of the piston 443 caused by local stress concentration.

[0041] Specifically, the handbrake assembly 44 further includes a limit pin 449. The limit pin 449 is disposed in the liquid storage cavity 4434 and extends along a preset direction. Herein, the direction in which the piston 443 moves closer to the elastic member 444 is defined as the preset direction, that is, the preset direction is the same as the compression direction of the elastic member 444.

[0042] The limit pin 449 is connected to the elastic member 444, and the elastic member 444 is radially limited by the limit pin 449 on the piston 443. Herein, the limit pin 449 and the piston 443 are integrally formed.

[0043] Furthermore, the limit pin 449 is provided as an injection molded part. By using a casting mold, molten plastic is injected into the mold, and the limit pin 449 can be obtained after cooling, which improves the production efficiency of the limit pin 449. Since the weight of the injection molded part is lighter than that of common metal materials such as aluminum alloy, it is beneficial to the lightweight design of the handbrake assembly 44.

[0044] In the implementation manner of the present application, a fixing groove 4416 is further formed in the pump body 441 (see Figure 4 ), the fixing groove 4416 is arranged around the oil outlet 4413, and the fixing groove 4416 is located at the part where the oil outlet 4413 is connected to the second chamber 4412. The elastic member 444 can be a conical spring. The end with a larger diameter of the conical spring is defined as the base of the conical spring, and the end with a smaller diameter of the conical spring is defined as the tip of the conical spring. When observed along the radial direction of the piston 443, the limit pin 449 has a convex portion 4491 (see Figure 5), the protrusion 4491 is arranged on the outer edge of the limit pin 449. The base of the conical spring is located in the fixing groove 4416, and the tip of the conical spring abuts against the protrusion 4491 of the limit pin 449. When the piston 443 moves, the base of the conical spring is subjected to a force in the direction opposite to the preset direction, and the tip of the conical spring is subjected to a force in the preset direction, causing the conical spring to be compressed along its own axial direction.

[0045] Through the above settings, during the working process of the parking brake assembly 44, the elastic member 444 is prevented from rubbing against the pump body 441 due to compression or rebound, improving the durability of the elastic member 444.

[0046] As Figure 6 shown, as an alternative implementation, the pump body 441 includes a fixing groove 4416 arranged around the oil outlet 4413, and the fixing groove 4416 is located at the part where the oil outlet 4413 is connected to the second chamber 4412. The piston 443 is provided with a fixing portion 4435. When observing along the axial direction of the piston 443, the fixing portion 4435 coincides with the fixing groove 4416. The elastic member 444 is set as a cylindrical spring, one end of the cylindrical spring is fixedly connected to the fixing portion 4435, and the other end of the cylindrical spring is located in the fixing groove 4416. The piston 443 is provided with a plurality of oil channels, and the oil channels extend from the second end 4432 of the piston 443 to the compensation hole 4433, so that the oil in the pressure chamber 4412a can flow through the oil channels to the compensation hole 4433.

[0047] As Figure 5 shown, as an implementation, an annular groove 4417 communicating with the oil delivery hole 4415 is formed on the inner wall of the pump body 441. The annular groove 4417 is located between the first seal 4451 and the second seal 4452, and there is a gap between the annular groove 4417 and the piston 443. Specifically, the inner diameter D1 of the annular groove 4417 is larger than the outer diameter D2 of the piston 443. The cross-section of the annular groove 4417 is trapezoidal, and the cross-section of the annular groove 4417 is parallel to the axis of the piston 443.

[0048] When the control handle 442 changes from the braking state to the initial state, the piston 443 moves in a direction away from the elastic member 444, causing the compensation hole 4433 to gradually separate from the second seal 4452. When the compensation hole 4433 does not overlap with the oil delivery hole 4415, the oil flowing out of the compensation hole 4433 can also be delivered to the oil delivery hole 4415 through the annular groove 4417, and then the oil flows into the first chamber 4411.

[0049] Through the above settings, the pressure relief speed when the control handle 442 changes from the braking state to the initial state is increased, and the control handle 442 is prevented from jamming.

[0050] It should be understood that those of ordinary skill in the art can make improvements or modifications based on the above description, and all such improvements and modifications shall fall within the protection scope of the appended claims of this application.

Claims

1. A handbrake assembly, comprising: Pump body; A control handle, the control handle is mounted on the pump body and can rotate relative to the pump body; A piston, the piston is arranged in the pump body and connected to the control handle; an elastic member, the elastic member being arranged in the pump body and abutting against the piston; It is characterized in that The handbrake assembly further includes a sealing component, which is fixed to the pump body and sleeved on the outer edge of the piston; the pump body has a first chamber, a second chamber connected to the first chamber, and an oil outlet connected to the second chamber, the first chamber is used to store oil, the piston is arranged in the second chamber and can move axially in the second chamber; one end of the piston is connected to the control handle, and the elastic member is located between the other end of the piston and the oil outlet and abuts against the piston; A compensation hole is provided on the piston. When the control handle is in an initial state, the compensation hole is communicated with the first chamber. When the control handle is in a braking state, the compensation hole is blocked by the sealing assembly.

2. The handbrake assembly according to claim 1, characterized in that: A mounting groove is formed in the pump body, and the mounting groove is used to install the sealing assembly and limit the sealing assembly in the axial direction.

3. The handbrake assembly according to claim 1, characterized in that: An oil delivery hole is opened between the first chamber and the second chamber, and the sealing assembly includes a first seal and a second seal. From the radial observation of the piston, the first seal and the second seal are respectively arranged on both sides of the oil delivery hole, and the second seal is located between the first seal and the oil outlet.

4. The handbrake assembly according to claim 3, characterized in that: When the control handle is in the braking state, the compensation hole is covered by the second sealing member.

5. The handbrake assembly according to claim 1, characterized in that: A liquid storage cavity is formed at one end of the piston abutting against the elastic member, and the liquid storage cavity is connected to the second chamber. The piston includes a side wall distributed circumferentially around the liquid storage cavity, and the compensation holes are located on the side wall and distributed around the liquid storage cavity.

6. The handbrake assembly according to claim 5, characterized in that: The handbrake assembly also includes a limit pin, which is arranged in the liquid storage cavity and extends along a preset direction. The limit pin is used to limit the compression direction of the elastic member, and the compression direction coincides with the preset direction.

7. The handbrake assembly according to claim 6, characterized in that: The pump body is also provided with a fixing groove, which is arranged around the oil outlet. A protrusion is provided on the outer edge of the limit pin. One end of the elastic member is arranged in the fixing groove, and the other end of the elastic member abuts against the protrusion.

8. The handbrake assembly according to claim 1, characterized in that: The inner wall of the pump body is provided with an annular groove connected with the oil delivery hole, the inner diameter of the annular groove is larger than the outer diameter of the piston, the cross section of the annular groove is trapezoidal, wherein the cross section of the annular groove is parallel to the axis of the piston.

9. The handbrake assembly according to claim 1, characterized in that: The handbrake assembly also includes a piston push rod, a dust cover and a retaining ring. The two ends of the piston push rod are respectively abutted against the control handle and the piston. The dust cover covers at least a portion of the piston push rod along the circumference of the piston push rod. The retaining ring is arranged between the dust cover and the piston. The dust cover and the retaining ring jointly seal the second chamber.

10. An all-terrain vehicle comprising: A walking system, the walking system comprising front wheels and rear wheels; A braking system, the braking system comprising a brake pedal, a brake pump and an ABS control module, the brake pedal transmits brake pressure to the ABS control module through the brake pump, and the ABS control module distributes the brake pressure to the front wheel and / or the rear wheel; It is characterized in that the braking system also includes a handbrake assembly as described in any one of claims 1-9.

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