Limiting brake cylinder

Abstract

The utility model provides a limiting brake cylinder, and belongs to the technical field of brake devices. The problem that the brake stroke of a piston in an existing brake cylinder is continuously increased is solved. The limiting brake cylinder comprises a cylinder body, a piston and a rod-shaped ejector rod, one side of the cylinder body is provided with a concave cavity, the piston extends into the concave cavity, the outer side of the piston is provided with an annular protruding shoulder, the outer side of the piston is sleeved with an annular limiting check ring, and an annular limiting groove is formed between the limiting check ring and the protruding shoulder. A limiting piece capable of preventing the limiting check ring from being separated from the piston in the direction of the bottom of the concave cavity is fixed to the outer side of the piston, the piston is further sleeved with an annular limiting ring, the outer side of the limiting ring is in close fit with the pump body, the limiting ring is located in the limiting groove, and the maximum width of the limiting groove in the axial direction of the piston is larger than the axial length of the limiting ring. And the piston can drive the limiting ring to move synchronously when moving towards the opening direction of the concave cavity. The limiting brake cylinder has the advantage of constant brake stroke.

Description

TECHNICAL FIELD

[0001] The utility model belongs to brake device technical field relates to a limit stop brake sub pump. BACKGROUND

[0002] Brake system is the important component part of vehicle safety use, including brake master cylinder and brake sub pump, and the brake sub pump is indispensable part of brake system.

[0003] The brake sub pump generally includes pump body, piston and top rod, the piston is inserted into the pump body, and the top rod is arranged at the outer end of the piston, and the top rod is used for cooperating and connecting with the brake structure such as rocker arm. When braking, the brake pedal is stepped on, the brake master cylinder delivers hydraulic oil to each brake sub pump through pipeline, the hydraulic oil drives the piston and the top rod to move outward to drive the brake structure to realize braking. After braking, the piston and the top rod are reset to the initial state by the restoring force of the brake structure.

[0004] However, in the process of long-term braking, the brake pad and other structures in the brake structure are worn, so that the piston and the top rod move outward to the effective braking stroke, and under the condition of the same pressure of hydraulic drive, the brake will be delayed. UTILITY MODEL CONTENTS

[0005] The utility model discloses a kind of limit stop brake sub pumps to solve the problem that the brake stroke of piston in existing brake sub pump is constantly increased.

[0006] The utility model discloses a kind of limit stop brake sub pumps to solve the problem that the brake stroke of piston in existing brake sub pump is constantly increased.

[0007] The limit stop brake sub pump includes pump body, piston and top rod, one side of the pump body has recessed cavity, the piston is inserted into the recessed cavity, and the outer side of the piston and the side wall of the recessed cavity form a seal, the other side of the pump body is provided with an oil inlet hole, characterized in that the outer side of the piston has a protruding annular shoulder, the outer side of the piston towards the bottom of the recessed cavity is provided with an annular limit stop ring, and an annular limit stop groove is formed between the limit stop ring and the shoulder, the outer side of the piston is fixed with a limit stop piece that can prevent the limit stop ring from separating from the piston towards the bottom of the recessed cavity, the outer side of the piston is also provided with an annular limit stop ring, and the outer side of the limit stop ring is tightly matched with the pump body, the limit stop ring is located in the limit stop groove, and the maximum width of the limit stop groove in the axial direction of the piston is greater than the axial length of the limit stop ring, when the piston moves towards the opening direction of the recessed cavity, the limit stop ring can be driven to move synchronously.

[0008] The limit stop brake master cylinder requires that the friction force between the limit ring and the pump body after tight fit is greater than the elastic restoring force of the brake structure. When the limit stop brake master cylinder is not braked, the other end of the jack relative to the piston is subjected to the elastic restoring force of the brake structure such as a rocker arm, and the piston is pushed to move into the concave cavity until the convex shoulder on one side of the limit groove abuts against the end face of the limit ring. Because the friction force between the limit ring and the pump body after tight fit is greater than the elastic restoring force of the brake structure, the limit ring will not move axially under the action of the elastic restoring force, and it remains stationary and blocks the piston. When braking starts, hydraulic oil is input from the oil inlet hole on the other side of the pump body into the concave cavity, and the hydraulic oil acts on the piston to push the piston and the jack to move outward to drive the brake structure to brake. When the brake pad of the brake structure is worn, the piston moves outward under the action of the oil pressure until the limit ring abuts against the other end of the limit stop ring on the other side of the limit groove, and the brake pad still has a gap between the brake disc, that is, effective braking has not been achieved, and then the oil pressure is further increased to push the piston and the limit stop ring to move outward synchronously to achieve effective braking. After braking, the piston and the jack are reset, and the limit ring remains stationary at the new position after movement under the action of the friction force, so that the piston can only be reset to the position where the convex shoulder abuts against the limit ring, and the next time the piston only needs to move to the position where the limit stop ring abuts against the limit ring under the action of the oil pressure to achieve effective braking. That is, the stroke of the piston to achieve effective braking each time is the difference between the axial length of the limit groove and the axial length of the limit ring, and the stroke can be kept substantially the same to avoid the situation that the brake is delayed due to wear of the brake pad.

[0009] In the limit stop brake master cylinder, a recessed annular groove is formed on the outer side of the one end of the piston towards the bottom of the concave cavity, the limit piece is annular and is arranged in the groove, and the limit piece extends out of the groove on the outer side and the limit stop ring can abut against the limit piece. The limit stop ring is limited by the annular groove and the limit piece extending out of the groove, and the structure is simple and the limiting effect is good.

[0010] In the limit stop brake master cylinder, the limit stop ring has a protruding abutting portion on the inner side of the one end towards the opening of the concave cavity, and the limit piece can penetrate into the bore of the limit stop ring and abut against the abutting portion. The limit piece can penetrate into the limit stop ring and abut against the abutting portion to limit the limit stop ring, which can better utilize the axial space of the piston and shorten the requirement for the axial length of the piston compared with the scheme that the limit piece directly limits the end of the limit stop ring, so that the structure of the entire brake master cylinder is more compact.

[0011] In the above-mentioned limit brake master cylinder, the limit stop ring has a protruding annular protrusion on the inner side of the end of the limit stop ring facing the opening of the recess, the outer side of the piston has a protruding annular boss, and the boss is located between the shoulder and the limit stop ring, the boss and the protrusion are oppositely arranged, and the outer diameter of the boss and the outer diameter of the protrusion are both smaller than the inner diameter of the limit ring. The boss and the protrusion are arranged so that the limit stop ring can be pushed open in advance when the piston is reset, leaving a gap.

[0012] In the above-mentioned limit brake master cylinder, a bleed hole is provided through the side wall of the bottom of the recess, and a bleed screw is threadedly connected to the pump body at the bleed hole. The air in the pump body can be discharged through the bleed screw.

[0013] In the above-mentioned limit brake master cylinder, the outer side of the shoulder has a recessed annular sealing groove, and a circular sealing ring is arranged in the sealing groove, the outer side of the sealing ring extends out of the sealing groove and abuts against the side wall of the recess. The sealing ring on the outer side of the shoulder realizes the sealing between the piston and the inner wall of the pump body.

[0014] In the above-mentioned limit brake master cylinder, the end of the piston facing the opening of the recess has a recess, and one end of the ejector rod extends into the recess. The recess facilitates the positioning of the ejector rod.

[0015] Compared with the prior art, the design of the limit ring and the limit groove in the limit brake master cylinder makes the effective braking stroke of the piston each time the brake is applied be the difference between the axial length of the limit groove and the axial length of the limit ring, which can keep the stroke substantially the same, avoid the occurrence of brake lag caused by wear of the brake pad, and improve safety. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic view of the sectional structure of the limit brake master cylinder.

[0017] In the figure, 1 is a pump body, 1a is a recess, 1b is an oil inlet hole, 1c is a bleed hole, 2 is a piston, 2a is a shoulder, 2b is a recess, 2c is a boss, 2d is a sealing groove, 2e is a recess, 3 is an ejector rod, 4 is a limit stop ring, 4a is an abutting portion, 4b is a protrusion, 5 is a limit groove, 6 is a limit member, 7 is a limit ring, 8 is a bleed screw, and 9 is a sealing ring. DETAILED DESCRIPTION

[0018] The following is a specific embodiment of the present utility model and further describes the technical scheme of the present utility model in combination with the drawings, but the present utility model is not limited to these embodiments.

[0019] For example, Figure 1As shown, the limit brake pump comprises a pump body 1, a piston 2 and a rod-shaped top rod 3. The pump body 1 has a recessed cylindrical recess 1a on one side, the piston 2 extends into the recess 1a and a seal is formed between the outer side of the piston 2 and the side wall of the recess 1a, and an oil inlet hole 1b is formed through the other side of the pump body 1. A vent hole 1c is formed through the side wall of the bottom of the recess 1a, and a vent screw 8 is threadedly connected to the pump body 1 at the vent hole 1c. The end of the piston 2 facing the opening of the recess 1a has a recessed notch 2e, and one end of the top rod 3 extends into the notch 2e. A dustproof cover in the shape of a cylinder is arranged at the opening of the recess 1a, one end of the dustproof cover is arranged around the opening of the recess 1a and is fixed with the pump body 1, and the other end is fixed with the outer side of the top rod 3.

[0020] The outer side of the piston 2 has a protruding annular shoulder 2a, the outer side of the shoulder 2a has a recessed annular sealing groove 2d, and a circular annular sealing ring 9 is arranged in the sealing groove 2d. The outer side of the sealing ring 9 extends out of the sealing groove 2d and abuts against the side wall of the recess 1a. The outer side of the end of the piston 2 facing the bottom of the recess 1a is provided with a recessed annular groove 2b, and a circular annular limit piece 6 made of metal material is arranged in the groove 2b. The outer side of the limit piece 6 extends out of the groove 2b. In this embodiment, the limit piece 6 is a snap ring which has a notch for easy installation.

[0021] The outer side of the end of the piston 2 facing the bottom of the recess 1a is provided with a circular annular limit stop ring 4, and the inner side of the end of the limit stop ring 4 facing the opening of the recess 1a has a protruding annular abutting portion 4a. The limit piece 6 can penetrate into the inner hole of the limit stop ring 4 and abut against the side of the abutting portion 4a facing the bottom of the recess 1a.

[0022] The limit stop ring 4 and the shoulder 2a form a circular annular limit groove 5, and the outer side of the piston 2 is further provided with a circular annular limit ring 7 which is tightly fitted with the pump body 1. The frictional force between the limit ring 7 and the pump body 1 is greater than the elastic restoring force of the existing rocker arm structure. The limit ring 7 is located in the limit groove 5, and the maximum width of the limit groove 5 in the axial direction of the piston 2 is greater than the axial length of the limit ring 7. When the piston 2 moves in the direction of the opening of the recess 1a, the limit ring 7 can be driven to move synchronously.

[0023] The inner side of the end of the limit stop ring 4 facing the opening of the recess 1a has a protruding annular convex portion 4b in the direction of the opening of the recess 1a, and the outer side of the piston 2 further has a protruding annular boss 2c. The boss 2c is located between the shoulder 2a and the limit stop ring 4, and the boss 2c is arranged adjacent to the shoulder 2a. The boss 2c and the convex portion 4b are arranged opposite to each other, and the outer diameter of the boss 2c and the outer diameter of the convex portion 4b are both smaller than the inner diameter of the limit ring 7. The distance between the boss 2c and the convex portion 4b is smaller than the difference between the length of the limit groove 5 in the axial direction of the piston 2 and the axial length of the limit ring 7.

[0024] The limit stop brake pump needs to be used with the existing brake structure such as a rocker arm. When installed, the outer end of the jacking rod 3 is connected with or abuts against the brake structure. When not braking, the other end of the jacking rod 3 relative to the piston 2 is subjected to the elastic return force of the brake structure such as a rocker arm, and the piston 2 is pushed to move into the concave cavity 1a until the convex shoulder 2a on one side of the limit groove 5 abuts against the end face of the limit ring 7. Since the friction force between the limit ring 7 and the pump body 1 after being tightly connected is greater than the elastic return force of the brake structure, the limit ring 7 will not move axially under the action of the elastic return force, and it remains stationary and blocks the piston 2.

[0025] When starting to brake, hydraulic oil is input from the oil inlet hole 1b on the other side of the pump body 1 into the concave cavity 1a, and the hydraulic oil acts on the piston 2 to push the piston 2 and the jacking rod 3 to move outward to drive the brake structure to brake.

[0026] When the brake pad of the brake structure is worn, the piston 2 moves outward under the action of the oil pressure until the limit ring 7 abuts against the limit stop ring 4 on the other side of the limit groove 5. At this time, the brake pad still has a gap between the brake disc, that is, effective braking has not been achieved. Therefore, the oil pressure is further increased to push the piston 2 and the limit stop ring 4 axially limited by the piston 2 to drive the limit ring 7 to move outward synchronously to achieve effective braking.

[0027] After braking, the piston 2 and the jacking rod 3 are reset, and the limit ring 7 remains stationary at the new position after moving under the action of the friction force, so that the piston 2 can only be reset until the convex shoulder 2a abuts against the limit ring 7. Therefore, the next time the piston 2 only needs to move to the limit stop ring 4 abutting against the limit ring 7 under the action of the oil pressure to achieve effective braking.

[0028] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art to which the present application belongs can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, without deviating from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A limited brake cylinder, comprising a pump body (1), a piston (2) and a rod-shaped push rod (3), wherein one side of the pump body (1) has a concave cavity (1a), the piston (2) extends into the cavity (1a) and a seal is formed between the outer side of the piston (2) and the side wall of the cavity (1a), and an oil inlet hole (1b) is formed through the other side of the pump body (1), characterized in that: The outer side of the piston (2) has a protruding annular shoulder (2a), and the outer side of the piston (2) facing the bottom of the cavity (1a) is provided with an annular limiting retaining ring (4), and an annular limiting groove (5) is formed between the limiting retaining ring (4) and the shoulder (2a). The outer side of the piston (2) is fixed with a limiting member (6) that can prevent the limiting retaining ring (4) from separating from the piston (2) toward the bottom of the cavity (1a). The outer side of the piston (2) is also provided with an annular limiting ring (7), and the outer side of the limiting ring (7) is tightly matched with the pump body (1). The limiting ring (7) is located in the limiting groove (5), and the maximum width of the limiting groove (5) in the axial direction of the piston (2) is greater than the axial length of the limiting ring (7). When the piston (2) moves toward the opening direction of the cavity (1a), it can drive the limiting ring (7) to move synchronously.

2. The limited brake cylinder according to claim 1, characterized in that: An annular groove (2b) is provided on the outer side of one end of the piston (2) facing the bottom of the cavity (1a); the limiting member (6) is annular and is arranged in the groove (2b); the outer side of the limiting member (6) extends out of the groove (2b) and the limiting retaining ring (4) can abut against the limiting member (6).

3. The limited brake cylinder according to claim 2, characterized in that: The inner side of one end of the limit retaining ring (4) that opens toward the cavity (1a) has a protruding abutting portion (4a), and the limit member (6) can penetrate into the inner hole of the limit retaining ring (4) and abut against the abutting portion (4a).

4. The limited brake cylinder according to claim 1, 2 or 3, characterized in that: The inner side of one end of the limit ring (4) facing the opening of the cavity (1a) has a convex portion (4b) in the shape of a circular ring that protrudes in the direction of the opening of the cavity (1a); the outer side of the piston (2) has a boss (2c) that protrudes in the shape of a circular ring, and the boss (2c) is located between the shoulder (2a) and the limit ring (4); the boss (2c) and the convex portion (4b) are arranged relative to each other, and the outer diameter of the boss (2c) and the outer diameter of the convex portion (4b) are both smaller than the inner diameter of the limit ring (7).

5. The limited brake cylinder according to claim 1, 2 or 3, characterized in that: A vent hole (1c) is provided through the side wall of the bottom of the cavity (1a), and a vent screw (8) is threadedly connected to the pump body (1) at the vent hole (1c).

6. The limited brake cylinder according to claim 1, 2 or 3, characterized in that: The outer side of the boss (2a) has a recessed annular sealing groove (2d), and a ring-shaped sealing ring (9) is arranged in the sealing groove (2d). The outer side of the sealing ring (9) extends out of the sealing groove (2d) and abuts against the side wall of the cavity (1a).

7. The limited brake cylinder according to claim 1, 2 or 3, characterized in that: One end of the piston (2) that opens toward the cavity (1a) has a recessed notch (2e), and one end of the push rod (3) extends into the notch (2e).

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