Brake master cylinder

Abstract

The utility model provides a brake master cylinder, and belongs to the technical field of brake systems. The brake master cylinder solves the problem that an existing brake master cylinder is not favorable for improving the response speed of continuous braking. The brake master pump comprises a pump body and a columnar piston, the pump body is provided with an oil inlet and a brake port, a pressure relief cavity communicated with a brake cavity, an oil supplementing cavity and an oil inlet cavity is formed in the piston, a pressure relief valve element and a pressure relief spring are arranged in the pressure relief cavity, and an oil supplementing channel communicated with the brake cavity and the oil inlet is further formed in the pump body. An oil supplementing valve element and an oil supplementing spring are arranged in the oil supplementing channel, and the oil supplementing valve element can overcome the elastic force of the oil supplementing spring to move under the action of oil pressure at the oil inlet and enable the brake cavity to be communicated with the oil inlet. The brake master cylinder has the advantage that the corresponding speed of continuous braking is high.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of brake system, and relates to a brake master cylinder. BACKGROUND

[0002] Among the existing brake master pumps with large oil displacement, one is divided into a brake chamber, an oil supplement chamber and an oil inlet chamber in sequence by a piston, and the cross-sectional area of the brake chamber is smaller than that of the oil inlet chamber. However, in the actual braking process of the brake master pump, the oil supplement speed of the oil supplement chamber into the brake chamber is slow with the inward pushing of the piston, which leads to the continuous increase of the oil pressure in the oil supplement chamber and causes great resistance to the movement of the piston and the push rod, which is not conducive to braking.

[0003] Therefore, the applicant designs a booster master pump and applies for a Chinese patent with the application number 202210247470.2 and the publication number CN114475547A. The booster master pump comprises a pump body and a piston assembly arranged in the pump body. The inner cavity of the pump body is divided into a brake chamber, an oil supplement chamber and an oil inlet chamber in sequence by the piston assembly. A sealing element allowing one-way flow of oil to the brake chamber is connected to the piston assembly between the brake chamber and the oil supplement chamber. The pump body has an oil inlet port in communication with the oil inlet chamber. The pump body also has an adjusting chamber with an adjusting valve core and an elastic element arranged therein. The adjusting chamber is in communication with the brake chamber, the oil supplement chamber and the oil inlet port. The adjusting valve core can block the communication between the oil supplement chamber and the oil inlet port under the elastic force of the elastic element. The adjusting valve core can move to connect the oil supplement chamber and the oil inlet port under the oil pressure of the brake chamber to overcome the elastic force of the elastic element. In the booster master pump, the adjusting chamber, the adjusting valve core and the elastic element in the adjusting chamber are used for pressure relief, and the oil in the oil supplement chamber is quickly discharged to the oil inlet port to reduce the braking resistance.

[0004] However, after braking is completed, the piston is reset, and the oil in the brake chamber is supplemented only by the oil supplement chamber through the one-way sealing sealing element, which has a slow oil supplement speed and is not conducive to improving the response speed of continuous braking. UTILITY MODEL CONTENTS

[0005] The utility model aims to solve the problem of the existing brake master pump that is not conducive to improving the response speed of continuous braking.

[0006] The utility model can be realized by the following technical solutions:

[0007] The brake master cylinder comprises a pump body with an oil inlet and a brake port and a cylindrical piston, the inner end of the piston extends into the pump body and separates the pump body into a brake chamber, an oil supplement chamber and an oil inlet chamber in sequence, characterized in that the piston is provided with a pressure relief chamber which is communicated with the brake chamber, the oil supplement chamber and the oil inlet chamber, the pressure relief chamber is provided with a pressure relief valve core and a pressure relief spring, the pressure relief valve core can block the brake chamber, the oil supplement chamber and the oil inlet chamber under the elastic force of the pressure relief spring, the pressure relief valve core can move against the elastic force of the pressure relief spring under the oil pressure of the brake chamber and make the oil supplement chamber and the oil inlet chamber communicated, the pump body is provided with an oil supplement channel which is communicated with the brake chamber and the oil inlet, the oil supplement channel is provided with an oil supplement valve core and an oil supplement spring, the oil supplement valve core can move against the elastic force of the oil supplement spring under the oil pressure of the oil inlet and make the brake chamber and the oil inlet communicated.

[0008] When the brake master cylinder brakes, the piston moves into the pump body, compresses the oil supplement chamber and the brake chamber, and outputs the oil in the brake chamber to the outside through the brake port to realize braking. Conversely, the piston resets. During the above braking process, when the oil pressure of the brake chamber rises to exceed the elastic force of the pressure relief spring, the oil pressure in the brake chamber pushes the pressure relief valve core in the pressure relief chamber to move against the elastic force of the pressure relief spring to make the oil supplement chamber and the oil inlet chamber communicated, and the high-pressure oil in the oil supplement chamber is discharged to the oil inlet chamber to reduce the resistance during the movement of the piston. When the piston resets, the oil pressure in the brake chamber decreases rapidly, while the oil pressure at the oil inlet is high, when the pressure difference between the two exceeds the elastic force of the oil supplement spring, the oil supplement valve core moves against the elastic force of the oil supplement spring and opens the oil supplement channel, and the oil in the oil inlet chamber supplements the oil in the brake chamber through the oil supplement channel, so that the piston resets quickly. In this way, by reducing the resistance during braking and quickly supplementing the oil during resetting, the response speed of the brake master cylinder during continuous braking is faster.

[0009] In the above brake master cylinder, the piston and the pump body are provided with annular cup one and cup two which are spaced apart along the axial direction of the piston, the cup one is closer to the brake chamber than the cup two, the inner wall of the pump body is provided with an annular groove, the cup one is arranged in the annular groove and the inner side of the cup one abuts against the outer wall of the piston, the outer side of the piston has an annular mounting groove, and the cup two is arranged in the mounting groove and the outer side of the cup two abuts against the inner wall of the pump body. By the spaced sealing arrangement of the cup one and the cup two, the pump body is separated into three chambers which are independent of each other by the piston.

[0010] In the brake master cylinder, the piston comprises two parts, part one and part two, which are coaxial and part two is sleeved on the outside of part one. The two parts each have a concave cavity at one end, and the two cavities form the pressure relief chamber. The piston is designed as a split structure, which facilitates the opening of the pressure relief chamber, the installation of the pressure relief valve core and the pressure relief spring, and the opening of other holes connected to the pressure relief chamber.

[0011] In the brake master cylinder, the piston has an axial hole at the inner end, which connects the brake chamber and the pressure relief chamber. The side of the piston has a side hole one and a side hole two, which connect the pressure relief chamber and the oil supplement chamber and the oil inlet chamber, respectively. The side hole one is closer to the brake chamber than the side hole two. The pressure relief chamber is connected to the brake chamber, the oil supplement chamber and the oil inlet chamber through the axial hole and the side hole one and the side hole two, which is simple in structure and convenient in hole opening.

[0012] In the brake master cylinder, the pressure relief valve core is cylindrical and coaxial with the piston. The two ends of the pressure relief valve core are fixed with two annular sealing rings. One of the sealing rings is arranged between the axial hole and the side hole one to form a seal between the pressure relief valve core and the side wall of the pressure relief chamber, and the other sealing ring is arranged between the side hole one and the side hole two to form a seal between the pressure relief valve core and the side wall of the pressure relief chamber. The axial hole, the side hole one and the side hole two are separated by the two sealing rings to block the oil circuit.

[0013] In the brake master cylinder, the piston inner end and the pump body inner wall are provided with a return spring and a spring seat. One end of the return spring abuts against the piston, and the other end of the return spring tightly presses the spring seat against the pump body inner wall. The spring seat limits and guides the return spring to ensure the stability of the return spring force.

[0014] Compared with the prior art, the brake master cylinder can reduce the resistance when the piston brakes, quickly supplement the brake chamber when the piston resets, and make the response speed of the brake master cylinder faster during continuous braking. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic view of the cross-sectional structure of the brake master cylinder.

[0016] In the figure, 1, pump body; 1a, oil inlet; 1b, brake port; 1c, brake cavity; 1d, oil supplement cavity; 1e, oil inlet cavity; 1f, oil supplement channel; 1g, annular groove; 2, piston; 2a, pressure relief cavity; 2b, mounting groove; 2c, part one; 2d, part two; 2e, axial hole; 2f, side hole one; 2g, side hole two; 3, pressure relief valve core; 4, pressure relief spring; 5, oil supplement valve core; 6, oil supplement spring; 7, cup one; 8, cup two; 9, sealing ring; 10, reset spring; 11, spring seat. DETAILED DESCRIPTION

[0017] The following is a specific embodiment of the utility model and further describes the technical scheme of the utility model in combination with the drawings, but the utility model is not limited to these embodiments.

[0018] As Figure 1 shown, the brake master cylinder, comprising a pump body 1 with an oil inlet 1a and a brake port 1b and a piston 2 in a cylindrical shape, the pump body 1 is recessed at one end to form a notch, the oil inlet 1a is opened in the side of the pump body 1, and the brake port 1b is opened through the end of the other end of the pump body 1. The inner end of the piston 2 extends into the pump body 1, and the piston 2 and the pump body 1 are spaced apart along the axial direction of the piston 2 and are provided with a cup one 7 and a cup two 8, which are both annular, to sequentially separate the brake cavity 1c, the oil supplement cavity 1d and the oil inlet cavity 1e in the pump body 1 from the bottom of the notch to the opening direction of the notch. In this embodiment, the cup one 7 is closer to the brake cavity 1c than the cup two 8, the inner wall of the pump body 1 is provided with an annular groove 1g, the cup one 7 is arranged in the annular groove 1g and the inner side of the cup one 7 abuts against the outer wall of the piston 2, the outer side of the piston 2 has an annular mounting groove 2b, and the cup two 8 is arranged in the mounting groove 2b and the outer side of the cup two 8 abuts against the inner wall of the pump body 1.

[0019] For the convenience of description, the end of the piston 2 extending into the pump body 1 is regarded as the inner end, and the other end is regarded as the outer end, and the other components are defined as inner and outer ends in the direction of the inner and outer ends of the piston 2.

[0020] The pump body 1 is further provided with a supplement oil channel 1f which is communicated with the brake cavity 1c and the oil inlet 1a, and the supplement oil channel 1f is provided with a supplement oil valve core 5 and a supplement oil spring 6, the supplement oil valve core 5 can be moved under the oil pressure at the oil inlet 1a to connect the brake cavity 1c and the oil inlet 1a by overcoming the elastic force of the supplement oil spring 6. In the embodiment, the supplement oil channel 1f includes a hole one which is opened along the axial direction of the piston 2, and a hole two which is opened along the radial direction of the piston 2, one end of the hole one is communicated with the oil inlet 1a, the other end of the hole one extends to the outside of the pump body 1, and the end of the hole one is threadedly connected with a plug for plugging the end of the hole one, one end of the hole two is communicated with the brake cavity 1c, the other end of the hole two is communicated with the hole one, the supplement oil valve core 5 and the supplement oil spring 6 are arranged in the hole one, the inner wall of the hole one between the supplement oil spring 6 and the oil inlet 1a is formed with an annular stepped surface, one end of the supplement oil valve core 5 passes through the stepped surface and is arranged towards the oil inlet 1a, the supplement oil spring 6 is arranged between the supplement oil valve core 5 and the plug, and the supplement oil valve core 5 is abutted on the stepped surface to block the hole one under the elastic force of the supplement oil spring 6, and the supplement oil valve core 5 has a gap between the side and the inner wall of the hole one for the oil to pass through.

[0021] The piston 2 is provided with a pressure relief cavity 2a which is communicated with the brake cavity 1c, the supplement oil cavity 1d and the oil inlet cavity 1e, the pressure relief cavity 2a is provided with a pressure relief valve core 3 and a pressure relief spring 4, and the pressure relief valve core 3 can block the brake cavity 1c, the supplement oil cavity 1d and the oil inlet cavity 1e by overcoming the elastic force of the pressure relief spring 4, and the pressure relief valve core 3 can be moved under the oil pressure of the brake cavity 1c to connect the supplement oil cavity 1d and the oil inlet cavity 1e by overcoming the elastic force of the pressure relief spring 4.

[0022] Specifically, the piston 2 includes a split one 2c and a split two 2d which are both in cylindrical shape, the split two 2d is coaxially arranged outside the outer end of the split one 2c, the end faces of the outer end of the split one 2c and the inner end of the split two 2d are both provided with recessed cavities, and the two recessed cavities form the pressure relief cavity 2a. In addition, the outer side of the outer end of the split one 2c is provided with a protruding circular ring-shaped protruding part one, the outer side of the inner end of the split two 2d is provided with a protruding circular ring-shaped protruding part two, and the inner end of the split two 2d is abutted on the end face of the protruding part one after the split two 2d is sleeved on the outer side of the split one 2c, and the protruding part one and the protruding part two form the mounting groove 2b for arranging the skin bowl two 8.

[0023] The inner end of the piston 2 is provided with an axial hole 2e which is communicated with the brake cavity 1c and the pressure relief cavity 2a along the axial direction, the side of the piston 2 is provided with a side hole one 2f which is communicated with the pressure relief cavity 2a and the supplement oil cavity 1d, and a side hole two 2g which is communicated with the pressure relief cavity 2a and the oil inlet cavity 1e, and the side hole one 2f is closer to the brake cavity 1c than the side hole two 2g.

[0024] The pressure relief cavity 2a is substantially cylindrical, and has a smaller diameter necked section at its inner end. The pressure relief valve core 3 is cylindrical and coaxial with the piston 2, and has a circular ring-shaped sealing ring 9 fixed at each end thereof, one of which is arranged between the axial hole 2e and the side hole 1, and forms a seal between the pressure relief valve core 3 and the side wall of the pressure relief cavity 2a, and the other is arranged between the side hole 1 and the side hole 2g, and forms a seal between the pressure relief valve core 3 and the side wall of the pressure relief cavity 2a. In this embodiment, the inner and outer ends of the pressure relief valve core 3 are outwardly convex to form a circular ring-shaped shoulder 1 and a shoulder 2, the shoulder 1 is located outwardly of the inner end of the pressure relief valve core 3, the shoulder 2 is located outwardly of the outer end of the pressure relief valve core 3, and the outer diameter of the shoulder 2 is greater than that of the shoulder 1, and the two sealing rings 9 are fixed outwardly of the shoulder 1 and the shoulder 2, respectively. The inner side of the split body 2d has a convex circular ring-shaped blocking portion, and the inner diameter of the blocking portion is smaller than the outer diameter of the shoulder 1, and when the shoulder 2 moves outwardly to abut against the blocking portion, the sealing ring 9 on the shoulder 1 is still located in the necked section of the pressure relief cavity 2a, and does not come out.

[0025] The piston 2 and the inner wall of the pump body 1 are provided with a return spring 10 and a spring seat 11, one end of the return spring 10 abuts against the piston 2, and the other end tightly presses the spring seat 11 against the inner wall of the pump body 1. The pump body 1 has two recesses, and a piston 2 is arranged in each recess, i.e. the brake master cylinder is a double-cavity pump, and the pump body 1 is provided with a balance hole which communicates the two recesses, and the balance hole is provided with a balance valve at each end, and the piston 2 can open the balance valve when moving inwardly. Here, the balance hole, the balance valve and the cooperating structure on the piston 2 are all prior art, and will not be described in detail.

[0026] When the brake master cylinder is braking, the outer end of the piston 2 is forced to move inwardly of the pump body 1, and the oil supplement cavity 1d and the brake cavity 1c are compressed, and the oil in the brake cavity 1c is outputted outwardly from the brake port 1b to realize braking. Conversely, under the elastic force of the return spring 10, the piston 2 is reset outwardly.

[0027] During braking, when the oil pressure of the brake cavity 1c continuously rises to exceed the elastic force of the pressure relief spring 4, the oil pressure in the brake cavity 1c pushes the pressure relief valve core 3 in the pressure relief cavity 2a to move against the elastic force of the pressure relief spring 4, so as to connect the oil supplement cavity 1d and the oil inlet cavity 1e, and the high-pressure oil in the oil supplement cavity 1d is discharged to the oil inlet cavity 1e, thereby reducing the resistance during the inward movement of the piston 2, and the brake cavity 1c remains disconnected with the oil supplement cavity 1d and the oil inlet cavity 1e.

[0028] When the brake ends and the piston 2 resets, the brake chamber 1c increases, the oil pressure in it decreases rapidly, and the oil pressure at the oil inlet 1a is high. When the pressure difference between the two exceeds the elastic force of the oil supplement spring 6, the oil supplement valve core 5 overcomes the elastic force of the oil supplement spring 6 and opens the oil supplement channel 1f, and the oil in the oil inlet 1a supplements the oil in the brake chamber 1c through the oil supplement channel 1f, so that the piston 2 resets quickly.

[0029] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, but will not deviate from the spirit of the present application or exceed the scope defined by the appended claims.

Claims

1. A brake master cylinder comprising a cylinder (1) having an oil inlet port (1a) and a brake port (1b), and a cylindrical piston (2) having an inner end extending into the cylinder (1) and dividing the cylinder (1) into a brake chamber (1c), an oil compensation chamber (1d) and an oil inlet chamber (1e) in this order, characterized in that, The piston (2) is provided with a pressure relief chamber (2a) communicated with the brake chamber (1c), the oil supplement chamber (1d) and the oil inlet chamber (1e), the pressure relief chamber (2a) is provided with a pressure relief valve core (3) and a pressure relief spring (4), the pressure relief valve core (3) can block the communication among the brake chamber (1c), the oil supplement chamber (1d) and the oil inlet chamber (1e) under the elastic force of the pressure relief spring (4), the pressure relief valve core (3) can move against the elastic force of the pressure relief spring (4) under the oil pressure of the brake chamber (1c) and make the oil supplement chamber (1d) and the oil inlet chamber (1e) communicated, the pump body (1) is provided with an oil supplement channel (1f) communicated with the brake chamber (1c) and the oil inlet (1a), the oil supplement channel (1f) is provided with an oil supplement valve core (5) and an oil supplement spring (6), the oil supplement valve core (5) can move against the elastic force of the oil supplement spring (6) under the oil pressure of the oil inlet (1a) and make the brake chamber (1c) and the oil inlet (1a) communicated.

2. The master brake cylinder according to claim 1, characterized in that The piston (2) and the pump body (1) are provided with a skin cup one (7) and a skin cup two (8) along the axial direction of the piston (2), the skin cup one (7) is closer to the brake chamber (1c) than the skin cup two (8), the inner wall of the pump body (1) is provided with an annular groove (1g), the skin cup one (7) is arranged in the annular groove (1g) and the inner side of the skin cup one (7) abuts against the outer wall of the piston (2), the outer side of the piston (2) is provided with an annular mounting groove (2b), the skin cup two (8) is arranged in the mounting groove (2b) and the outer side of the skin cup two (8) abuts against the inner wall of the pump body (1).

3. The master brake cylinder according to claim 1 or 2, characterized in that The piston (2) includes a split one (2c) and a split two (2d), the split one (2c) and the split two (2d) are coaxially arranged, and the split two (2d) is sleeved on the outer side of the split one (2c) at one end thereof, the split one (2c) and the split two (2d) are both provided with a concave cavity at one end thereof, and the two concave cavities form the pressure relief chamber (2a).

4. The master brake cylinder according to claim 1 or 2, characterized in that The inner end of the piston (2) is provided with an axial hole (2e) communicated with the brake chamber (1c) and the pressure relief chamber (2a), the side of the piston (2) is provided with a side hole one (2f) communicated with the pressure relief chamber (2a) and the oil supplement chamber (1d) and a side hole two (2g) communicated with the pressure relief chamber (2a) and the oil inlet chamber (1e), the side hole one (2f) is closer to the brake chamber (1c) than the side hole two (2g).

5. The master brake cylinder according to claim 4, characterized in that The pressure relief valve core (3) is cylindrical and coaxially arranged with the piston (2), the outer side of both ends of the pressure relief valve core (3) is fixed with a sealing ring (9), one of the sealing rings (9) is arranged between the axial hole (2e) and the side hole one (2f) and forms a seal between the pressure relief valve core (3) and the side wall of the pressure relief chamber (2a), the other sealing ring (9) is arranged between the side hole one (2f) and the side hole two (2g) and forms a seal between the pressure relief valve core (3) and the side wall of the pressure relief chamber (2a).

6. The master brake cylinder according to claim 1 or 2, characterized in that The inner end of the piston (2) and the inner wall of the pump body (1) are provided with a reset spring (10) and a spring seat (11), one end of the reset spring (10) abuts against the piston (2), and the other end tightly presses the spring seat (11) on the inner wall of the pump body (1).

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