master cylinder

Abstract

This utility model provides a brake master cylinder, belonging to the technical field of brake system technology. It solves the problem of resistance to piston movement caused by the continuous increase in oil pressure in the replenishing chamber of existing brake pumps. This brake master cylinder includes a pump body and a piston. The piston sequentially divides the pump body cavity into a brake chamber, a replenishing chamber, and an inlet chamber. A recessed hole is formed at the inner end of the piston, and two side holes are formed on the side of the piston. The key feature is that a columnar pressure relief block is axially fixed within the recessed hole. The pressure relief block and the side wall of the recessed hole are sealed by two spaced-apart, annular sealing rings. A pressure relief hole connecting the two side holes is formed within the pressure relief block. A pressure relief valve core and a pressure relief spring are installed within the pressure relief block. This brake master cylinder has the advantage of low piston movement resistance.

Description

Technical Field

[0001] This utility model belongs to the field of braking system technology and relates to a brake master cylinder. Background Technology

[0002] With the continuous development of the motor vehicle industry, vehicle usage is constantly increasing, and people's requirements for vehicle comfort and safety are also constantly rising. The clutch and braking system of a vehicle plays a very important role in the process of vehicle use, and the brake pump is a device used to assist in the operation of the vehicle's braking system.

[0003] In existing large-displacement brake master cylinders, one type uses a piston to sequentially divide the master cylinder's internal cavity into a brake chamber, a replenishing chamber, and an inlet chamber. The cross-sectional area of ​​the brake chamber is smaller than that of both the replenishing and inlet chambers, and the piston's outer side is used to separate the three chambers. However, during actual braking, with the piston moving, the replenishing chamber replenishes oil to the brake chamber relatively slowly through the replenishing chamber, causing the oil pressure in the replenishing chamber to continuously increase. This creates significant resistance to the movement of the piston and push rod, which is detrimental to braking. Utility Model Content

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a brake master cylinder that solves the problem of resistance to piston movement caused by the continuous increase in oil pressure in the oil replenishment chamber of existing brake pumps.

[0005] The objective of this utility model can be achieved through the following technical solutions: A brake master cylinder includes a pump body and a cylindrical piston passing through the pump body. The piston sequentially divides the internal cavity of the pump body into a brake chamber, a replenishing chamber, and an inlet chamber. An axially recessed recess is formed at the inner end of the piston. A side hole connecting the replenishing chamber and the recess, and a second side hole connecting the inlet chamber and the recess, are formed on the side of the piston. The cylinder is characterized in that a cylindrical pressure relief block is axially fixed within the recess. The pressure relief block is separated from the sidewall of the recess by two annularly spaced, tightly sealed... The sealing rings form a seal, and the two sealing rings are respectively located between the opening end of the concave hole and side hole one, and between side hole one and side hole two. The pressure relief block has a pressure relief hole that can connect side hole one and side hole two. The pressure relief block is provided with a pressure relief valve core and a pressure relief spring. The pressure relief valve core can move towards the opening direction of the concave hole under the elastic force of the pressure relief spring and block the pressure relief hole. The pressure relief valve core can overcome the elastic force of the pressure relief spring and move under the oil pressure in the oil replenishment chamber and make the pressure relief hole open.

[0006] The pump body in this master cylinder has an existing structure, with an inlet port communicating with the oil inlet chamber and an outlet port communicating with the brake chamber. When the pump body is not braking, the two sealing rings between the pressure relief block and the side wall of the concave hole separate the opening of the concave hole, side hole one, and side hole two. The pressure relief hole connecting side hole one and side hole two is blocked by the pressure relief valve core moving towards the opening of the concave hole, i.e., towards the brake chamber, under the elastic force of the pressure relief spring, thus preventing communication between the brake chamber, the replenishing chamber, and the inlet chamber. When braking begins, the piston receives axial thrust from external push rods and other components, moving towards the brake chamber. The inlet port delivers external oil into the inlet chamber, increasing the oil pressure within the inlet chamber and providing assistance for the piston's inward movement. The replenishing chamber and the brake chamber are compressed. The oil pressure in the oil replenishment chamber continuously increases until it acts on the pressure relief valve core, causing it to overcome the elastic force of the pressure relief spring and move, thus opening the pressure relief hole. The oil in the oil replenishment chamber can then flow sequentially through side hole one, oil drain hole, and side hole two to the oil inlet chamber, thereby relieving the pressure in the oil replenishment chamber and reducing the resistance to piston inward movement.

[0007] In this brake master cylinder, two sealing rings that isolate the brake chamber, the replenishing chamber, and the inlet chamber are positioned between the stationary pressure relief block and the sidewall of the recessed hole. This prevents the sealing rings from wearing down during the opening and closing of the pressure relief hole, ensuring sealing performance and service life. Furthermore, the pressure relief valve core and pressure relief spring are housed within the pressure relief block and can be installed together into the piston's recessed hole after installation within the block. This facilitates assembly and prevents the pressure relief valve core and spring from shifting or wobbling during assembly, resulting in better structural stability and reliability.

[0008] In the aforementioned brake master cylinder, the pressure relief port includes an axial hole extending along the axial direction of the pressure relief block, and radial holes one connecting the axial hole and the side hole, and radial holes two connecting the side hole and the axial hole, both extending radially along the pressure relief block. The side wall of the axial hole located between radial holes one and two within the pressure relief block has a protruding, annular shoulder. A gap exists between the outer side of the pressure relief valve core and the wall of the axial hole, and the pressure relief valve core can abut against the shoulder and seal the axial hole under the elastic force of the pressure relief spring. This hole design, utilizing the axial hole, radial holes one, and radial holes two, not only facilitates the installation of the pressure relief valve core but also prevents the oil in the replenishment chamber from impacting the pressure relief valve core, ensuring the stability of the seal between the pressure relief valve core and the shoulder.

[0009] In the aforementioned master cylinder, the pressure relief valve core is spherical, and a columnar pressure relief seat is provided between the pressure relief valve core and the pressure relief spring. The pressure relief seat has a protruding annular flange on its outer side facing the pressure relief valve core. One end of the pressure relief spring is fitted onto the outer side of the pressure relief seat and abuts against the flange, while the other end of the pressure relief spring abuts against the pressure relief block. The end face of the pressure relief seat facing the pressure relief valve core is flat. The pressure relief seat between the pressure relief valve core and the pressure relief spring ensures stable actuation of the pressure relief valve core.

[0010] In the aforementioned master cylinder, the pressure relief block includes an adjacent sealing seat and a spring seat, with the sealing seat closer to the brake chamber than the spring seat. Radial holes one and two are formed on the sealing seat. The spring seat is recessed on one side facing the sealing seat, forming a notch. The other end of the pressure relief spring, relative to the pressure relief valve core, abuts against the bottom of the notch. Dividing the pressure relief block into a sealing seat and a spring seat facilitates the machining of the pressure relief block and the installation of the pressure relief valve core and spring.

[0011] In the aforementioned master cylinder, the axial hole faces the brake chamber and extends to the end of the pressure relief block, communicating with the brake chamber. A replenishing valve core and a replenishing spring are installed in the recess between the first side hole and the opening end of the recess. The replenishing valve core can move towards the pressure relief block under the elastic force of the replenishing spring, thus blocking the connection between the first side hole and the brake chamber. By installing the replenishing valve core and the replenishing spring in the recess between the first side hole and the brake chamber, the replenishing valve core can be pushed open and replenished with oil after the oil pressure in the replenishing chamber increases, thereby accelerating the replenishment speed and reducing the resistance to piston inward movement.

[0012] In the aforementioned master cylinder, a tubular pressure relief cylinder is inserted into the axial hole of the pressure relief block. A seal is formed between the outer circumference of the pressure relief cylinder facing the brake cavity and the pressure relief block. The replenishing valve core, under the elastic force of the replenishing spring, abuts against the port of the pressure relief cylinder facing the brake cavity, forming a seal. A gap exists between the outer side of the other end of the pressure relief cylinder and the pressure relief block, and the port of the other end of the pressure relief cylinder abuts against the pressure relief valve core. A through hole, always connected to the radial hole, is provided through the side of the pressure relief cylinder. By incorporating the pressure relief cylinder, the travel distance of the replenishing valve core is shortened, improving the response speed.

[0013] In the aforementioned master cylinder, the outer diameter of the pressure relief cylinder at one end facing the brake chamber is larger than the outer diameter at the other end, and a stepped surface is formed on the outer side of the middle part of the pressure relief cylinder. The inner wall of the pressure relief block has a protruding, annular shoulder. When the pressure relief valve core abuts against the shoulder, there is a gap between the stepped surface and the shoulder. The gap between the stepped surface and the shoulder divides the opening of the pressure relief valve core into two parts: first, it moves away from the shoulder, and then it moves away from the pressure relief cylinder, forming a two-stage pressure relief state, achieving pressure relief while ensuring the oil replenishment speed.

[0014] Compared with existing technologies, this brake master cylinder has the following advantages: 1. By setting up the oil replenishment valve core and oil replenishment spring, the oil in the oil replenishment chamber can be quickly replenished to the brake chamber, ensuring the braking effect while reducing the resistance of piston inward movement.

[0015] 2. By setting up the pressure relief valve core and pressure relief spring, the oil in the oil replenishment chamber can be discharged into the oil inlet chamber to quickly reduce the resistance of the piston moving inward.

[0016] 3. Two sealing rings, used to block the brake chamber, oil replenishment chamber and oil inlet chamber from each other, are placed between the fixed pressure relief block and the side wall of the concave hole, so that the sealing rings will not wear during the opening and closing of the pressure relief hole, thus ensuring sealing performance and service life.

[0017] 4. The pressure relief valve core and pressure relief spring are located inside the pressure relief block. They can be installed together into the concave hole of the piston after being installed inside the pressure relief block. This makes assembly more convenient and the pressure relief valve core and pressure relief spring are less likely to shift or wobble during assembly, resulting in better structural stability and reliability. Attached Figure Description

[0018] Figure 1 This is a cross-sectional structural schematic diagram of Embodiment 1 of the brake master cylinder.

[0019] Figure 2 This is a partial enlarged view of the pressure relief valve core in Embodiment 1 of this brake master cylinder.

[0020] Figure 3 This is a partial enlarged view of the pressure relief valve core in Embodiment 2 of this brake master cylinder.

[0021] Figure 4 This is a partial enlarged view of the pressure relief valve core in Embodiment 3 of this brake master cylinder.

[0022] In the diagram, 1. Pump body; 11. Braking chamber; 12. Oil replenishing chamber; 13. Oil inlet chamber; 2. Piston; 21. Concave hole; 22. Side hole one; 23. Side hole two; 3. Pressure relief block; 31. Pressure relief hole; 32. Axial hole; 33. Radial hole one; 34. Radial hole two; 35. Shoulder; 36. Sealing seat; 37. Spring seat; 38. Notch; 39. Shoulder; 4. Sealing ring; 5. Pressure relief valve core; 6. Pressure relief spring; 7. Pressure relief seat; 71. Edge; 8. Oil replenishing valve core; 9. Oil replenishing spring; 10. Pressure relief cylinder; 101. Through hole; 102. Stepped surface. Detailed Implementation

[0023] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments. Example 1

[0024] like Figure 1 As shown, this brake master cylinder includes a pump body 1 with an inlet and an outlet, and a cylindrical piston 2 with its inner end inserted inside the pump body 1. Two annular cups are fixed at intervals on the outer side of the piston 2. Through these two cups, the inner cavity of the pump body 1 is sequentially divided from the inside to the outside into a brake chamber 11, a replenishing chamber 12, and an inlet chamber 13. The inlet is connected to the inlet chamber 13, and the outlet is connected to the brake chamber 11. An axially recessed recess 21 is provided at the inner end of the piston 2. A side hole 22 connecting the replenishing chamber 12 and the recess 21, and a side hole 23 connecting the inlet chamber 13 and the recess 21 are provided on the side of the piston 2.

[0025] like Figure 2 As shown, a columnar pressure relief block 3 is axially fixed inside the recess 21. The axial direction of the pressure relief block 3 is consistent with the axial direction of the piston 2. Two annular sealing rings 4 are spaced apart on the outer side of the pressure relief block 3. The two sealing rings 4 form a seal between the pressure relief block 3 and the side wall of the recess 21. The two sealing rings 4 are located between the opening end of the recess 21 and the first side hole 22, and between the first side hole 22 and the second side hole 23, respectively. The pressure relief block 3 has a pressure relief hole 31 that connects the first side hole 22 and the second side hole 23. The pressure relief block 3 is equipped with a pressure relief valve core 5 and a pressure relief spring 6. The pressure relief valve core 5 can move towards the opening direction of the recess 21 under the elastic force of the pressure relief spring 6 and block the pressure relief hole 31. The pressure relief valve core 5 can overcome the elastic force of the pressure relief spring 6 and move under the oil pressure in the oil replenishment chamber 12, thus opening the pressure relief hole 31.

[0026] Specifically, the pressure relief block 3 includes an adjacent sealing seat 36 and a spring seat 37, with the sealing seat 36 closer to the brake chamber 11 than the spring seat 37. The recess 21 is a stepped hole. The aforementioned sealing ring 4, fitted on the outer side of the inner end of the sealing seat 36, abuts against the step to achieve axial limitation of the inner end of the sealing seat 36. A circular retaining ring is fixed on the inner side of the piston 2 at the outer end of the spring seat 37, which achieves axial limitation of the outer end of the spring seat 37. That is, the step of the recess 21 and the retaining ring achieve axial limitation of the two ends of the pressure relief block 3 composed of the sealing seat 36 and the spring seat 37.

[0027] The pressure relief hole 31 includes an axial hole 32 opened along the axial direction of the pressure relief block 3, and a radial hole 33 that connects the side hole 22 and the axial hole 32, and a radial hole 34 that connects the side hole 23 and the axial hole 32. The side wall of the axial hole 32 located between the radial hole 33 and the radial hole 34 in the pressure relief block 3 has a protruding annular shoulder 35. There is a gap between the outer side of the pressure relief valve core 5 and the hole wall of the axial hole 32 for oil to flow to the radial hole 34. The pressure relief valve core 5 can abut against the shoulder 35 and block the axial hole 32 under the elastic force of the pressure relief spring 6.

[0028] In this embodiment, the rear end face of the sealing seat 36 is recessed, and the front end face of the spring seat 37 is recessed to form a notch 38. After the two abut against each other, the aforementioned axial hole 32 is formed. Radial hole one 33 and radial hole two 34 are both opened on the side of the sealing seat 36. The pressure relief valve core 5 is spherical, and a columnar pressure relief seat 7 is also provided between the pressure relief valve core 5 and the pressure relief spring 6. The outer side of the pressure relief seat 7 facing the pressure relief valve core 5 has a protruding annular retaining edge 71. One end of the pressure relief spring 6 is sleeved on the outer side of the pressure relief seat 7 and abuts against the rear end face of the retaining edge 71. The other end of the pressure relief spring 6 abuts against the bottom of the notch 38 of the spring seat 37. The end face of the pressure relief seat 7 facing the pressure relief valve core 5 is flat.

[0029] When the pump body 1 in this master cylinder is not braking, the two sealing rings 4 between the pressure relief block 3 and the side wall of the concave hole 21 separate the opening of the concave hole 21, side hole 1 22 and side hole 23. The pressure relief hole 31 connecting side hole 1 22 and side hole 23 is sealed by the pressure relief valve core 5 moving towards the opening of the concave hole 21, that is, towards the brake chamber 11, under the elastic force of the pressure relief spring 6, and abutting against the shoulder 35, thus blocking the pressure relief hole 31 and making the brake chamber 11, the oil replenishment chamber 12 and the oil inlet chamber 13 not connected to each other.

[0030] When braking begins, piston 2 receives axial thrust from external components such as the push rod and moves towards brake chamber 11. The oil inlet sends external oil into oil inlet chamber 13, increasing the oil pressure within 13 and providing assistance for piston 2's inward movement. Oil replenishment chamber 12 and brake chamber 11 are compressed. The oil pressure in replenishment chamber 12 continuously increases until it acts on the pressure relief valve core 5, causing it to overcome the elastic force of pressure relief spring 6 and move away from shoulder 35. This opens pressure relief hole 31, allowing oil in replenishment chamber 12 to flow sequentially through side hole 22, radial hole 33, the gap between the wall of axial hole 32 and pressure relief valve core 5, radial hole 34, and side hole 23 to oil inlet chamber 13, thus relieving pressure in replenishment chamber 12 and reducing resistance to piston 2's inward movement. Example 2

[0031] like Figure 3As shown, the technical solution of this embodiment is largely the same as that of Embodiment 1, except that: the end of the axial hole 32 facing the brake cavity 11 passes through the sealing end and extends to the end of the inner end of the pressure relief block 3, communicating with the brake cavity 11. A protruding step is also provided on the side wall of the recess 21 between the inner end of the pressure relief block 3 and the opening end of the recess 21. A spherical oil replenishing valve core 8 and an oil replenishing spring 9 are provided in the recess 21 between the step and the pressure relief block 3. One end of the oil replenishing spring 9 abuts against the step, and the other end abuts against the oil replenishing valve core 8. The oil replenishing valve core 8 can move towards the pressure relief block 3 under the elastic force of the oil replenishing spring 9 and abut against the port of the inner end of the axial hole 32 to achieve a seal, thus blocking the connection between the side hole 22 and the brake cavity 11. Here, the spring force of the replenishing valve core 8 when it abuts against the pressure relief block 3 is less than the spring force of the pressure relief valve core 5 when it abuts against the shoulder 35. That is, after the oil pressure in the replenishing chamber 12 increases, the replenishing valve core 8 is opened first, so that the replenishing chamber 12 replenishes oil to the brake chamber 11. After the oil pressure in the replenishing chamber 12 continues to increase, the pressure relief valve core 5 is opened to discharge oil to the inlet chamber 13. Example 3

[0032] like Figure 4 As shown, the technical solution of this embodiment is largely the same as that of Embodiment 2, except that: one of the two sealing rings 4, the one closer to the brake chamber 11, is located between the inner end of the sealing seat 36 and the step; a cylindrical pressure relief cylinder 10 is inserted into the axial hole 32 of the pressure relief block 3; the outer circumferential surface of the inner end of the pressure relief cylinder 10 abuts against the inner side of the sealing ring 4 located at the inner end of the pressure relief block 3 and forms a seal. The oil replenishing valve core 8 can abut against the port of the inner end of the pressure relief cylinder 10 under the elastic force of the oil replenishing spring 9 and form a seal; there is a gap between the outer side of the outer end of the pressure relief cylinder 10 and the wall of the axial hole 32 of the pressure relief block 3; and the port of the outer end of the pressure relief cylinder 10 can abut against the pressure relief valve core 5; and a through hole 101, which is always connected to the radial hole 33, is opened through the side of the pressure relief cylinder 10. The outer diameter of the inner end of the pressure relief cylinder 10 is larger than the outer diameter of the outer end, and a stepped surface 102 is formed on the outer side of the middle part of the pressure relief cylinder 10. The inner wall of the pressure relief block 3 has a protruding annular shoulder 39. The shoulder 39 is located between the stepped surface 102 and the pressure relief valve core 5. When the pressure relief valve core 5 abuts against the shoulder 35 and the outer end of the pressure relief cylinder 10 abuts against the pressure relief valve core 5, there is a gap between the stepped surface 102 and the shoulder 39.

[0033] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A brake master cylinder, comprising a pump body (1) and a cylindrical piston (2) passing through the pump body (1), wherein the piston (2) sequentially divides the inner cavity of the pump body (1) into a brake chamber (11), a replenishing chamber (12), and an inlet chamber (13), wherein the inner end of the piston (2) is provided with an axially recessed recess (21), and the side of the piston (2) is provided with a side hole one (22) connecting the replenishing chamber (12) and the recess (21) and a side hole two (23) connecting the inlet chamber (13) and the recess (21), characterized in that, A columnar pressure relief block (3) is axially fixed inside the recess (21). The pressure relief block (3) and the side wall of the recess (21) are sealed by two spaced and annular sealing rings (4). The two sealing rings (4) are located between the opening end of the recess (21) and the first side hole (22) and between the first side hole (22) and the second side hole (23), respectively. The pressure relief block (3) is provided with a pressure relief hole (31) that can connect the first side hole (22) and the second side hole (23). The pressure relief block (3) is provided with a pressure relief valve core (5) and a pressure relief spring (6). The pressure relief valve core (5) can move towards the opening direction of the recess (21) under the elastic force of the pressure relief spring (6) and block the pressure relief hole (31). The pressure relief valve core (5) can overcome the elastic force of the pressure relief spring (6) and move under the oil pressure in the oil replenishment chamber (12) and make the pressure relief hole (31) open.

2. The brake master cylinder according to claim 1, characterized in that, The pressure relief hole (31) includes an axial hole (32) opened along the axial direction of the pressure relief block (3), a radial hole (33) connecting the side hole (22) and the axial hole (32) and a radial hole (34) connecting the side hole (23) and the axial hole (32) respectively. The side wall of the axial hole (32) located between the radial hole (33) and the radial hole (34) in the pressure relief block (3) has a protruding annular shoulder (35). There is a gap between the outer side of the pressure relief valve core (5) and the hole wall of the axial hole (32). The pressure relief valve core (5) can abut against the shoulder (35) and block the axial hole (32) under the elastic force of the pressure relief spring (6).

3. The brake master cylinder according to claim 2, characterized in that, A columnar pressure relief seat (7) is also provided between the pressure relief valve core (5) and the pressure relief spring (6). The pressure relief seat (7) has a protruding annular retaining edge (71) on the outer side of one end facing the pressure relief valve core (5). One end of the pressure relief spring (6) is sleeved on the outer side of the pressure relief seat (7) and abuts against the retaining edge (71). The other end of the pressure relief spring (6) abuts against the pressure relief block (3). The end face of the pressure relief seat (7) facing the pressure relief valve core (5) is a plane.

4. The brake master cylinder according to claim 3, characterized in that, The pressure relief block (3) includes a sealing seat (36) and a spring seat (37) arranged adjacent to each other, and the sealing seat (36) is closer to the brake chamber (11) than the spring seat (37). The radial hole one (33) and the radial hole two (34) are opened on the sealing seat (36). The spring seat (37) is recessed on one side facing the sealing seat (36) to form a notch (38). The pressure relief spring (6) abuts against the bottom of the notch (38) at the other end relative to the pressure relief valve core (5).

5. The brake master cylinder according to any one of claims 2 to 4, characterized in that, The axial hole (32) is opened at one end facing the brake chamber (11) and connected to the end of the pressure relief block (3). The concave hole (21) between the side hole (22) and the opening end of the concave hole (21) is provided with a replenishing valve core (8) and a replenishing spring (9). The replenishing valve core (8) can move towards the pressure relief block (3) under the elastic force of the replenishing spring (9) and block the connection between the side hole (22) and the brake chamber (11).

6. The brake master cylinder according to claim 5, characterized in that, A tubular pressure relief cylinder (10) is inserted through the axial hole (32) of the pressure relief block (3). The outer peripheral surface of the pressure relief cylinder (10) facing the brake chamber (11) forms a seal with the pressure relief block (3). The oil replenishing valve core (8) can abut against the port of the pressure relief cylinder (10) facing the brake chamber (11) under the elastic force of the oil replenishing spring (9) and form a seal. There is a gap between the outer side of the other end of the pressure relief cylinder (10) and the pressure relief block (3), and the port of the other end of the pressure relief cylinder (10) can abut against the pressure relief valve core (5). The side of the pressure relief cylinder (10) is provided with a through hole (101) that is always connected to the radial hole (33).

7. The brake master cylinder according to claim 6, characterized in that, The outer diameter of the pressure relief cylinder (10) facing the brake chamber (11) is larger than the outer diameter of the other end, and a stepped surface (102) is formed on the outer side of the middle part of the pressure relief cylinder (10). The inner wall of the pressure relief block (3) has a protruding annular shoulder (39). When the pressure relief valve core (5) abuts against the shoulder (35), there is a gap between the stepped surface (102) and the shoulder (39).

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