CN213839349U

CN213839349U - Oil circuit structure of braking system

Info

Publication number: CN213839349U
Application number: CN202022479390.9U
Authority: CN
Inventors: 许甫; 高振家; 赵林宾; 蔡一宇; 王星星
Original assignee: Zhejiang Haihong Hydraulic Technology Co ltd
Current assignee: Zhejiang Haihong Hydraulic Technology Co ltd
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2021-07-30
Anticipated expiration: 2030-10-30

Abstract

The utility model provides a braking system's oil circuit structure belongs to stopper technical field. The brake system solves the problem that the temperature of gear oil in cavities of the dynamic friction plate and the static friction plate in the conventional brake system is too high. This braking system's oil circuit structure, braking system includes the spindle nose, the wheel hub of cover on the spindle nose is established and the cylinder body of cover on wheel hub is established, the oil pocket has between spindle nose and the wheel hub, the cylinder body has the installation cavity, the transition ring flange has in the installation cavity, set up the braking piece on the cylinder body and set up the friction disc on wheel hub, oil feed passageway one has in the cylinder body, oil feed passageway two, piston cavity one with oil feed passageway one intercommunication and piston cavity two with oil feed passageway two intercommunication, be equipped with the parking piston in the piston cavity two, be equipped with the driving piston in the piston cavity one, this oil circuit structure is including the oil gallery that is located between installation cavity and the oil pocket, the oil gallery is seted up on wheel hub, the oil storage chamber has between transition ring flange and the driving piston. This braking system's oil circuit structure can promote the life of sealing member.

Description

Oil circuit structure of braking system

Technical Field

The utility model belongs to the technical field of the stopper, refer in particular to a braking system's oil circuit structure.

Background

In the process of coal mining, a rail car is generally adopted to transport coal under a mine out of the mine, after the coal is stacked on the rail car, the weight of the rail car is very heavy, when the rail car runs out of the mine, the rail car needs to be braked, and as the rail car runs out of the mine, the rail car has very large kinetic energy, a hydraulic brake is generally configured on the rail car to brake the rail car.

Existing brake systems, such as chinese patent application [ application publication No.: CN204284256U discloses a double-acting wet hydraulic brake for a pick-up truck, which comprises a brake shell connected with an axle housing of the pick-up truck, wherein the brake shell comprises a first sealing ring and a second sealing ring which are arranged in a groove of the brake shell, and a brake seat, the brake seat comprises a friction plate, a first oil seal and a first screw, the first oil seal is used for sealing oil in an oil cavity of the brake, the friction plate is connected with the brake seat through a spline and can move axially relatively, the brake seat is connected with a pick-up semi-axle through the first screw, the inner gear also comprises an inner gear ring, the inner gear ring comprises a dual plate, the inner gear ring is connected with the brake shell through a second screw, the dual plate is connected with the inner gear ring through the spline and can move axially relatively, the brake seat further comprises a flange cover, the flange cover comprises a second oil seal, the flange cover is connected with the inner gear ring through a third screw, the second oil seal is used for sealing the oil cavity of the brake, the parking piston comprises a third sealing ring, a fourth sealing ring and a parking piston, the third sealing ring and the fourth sealing ring are installed in a groove of the parking piston, the parking piston is installed in an inner gear ring and forms a first oil cylinder in the third sealing ring and the fourth sealing ring, the parking piston further comprises a traveling piston, the traveling piston comprises a limiting bolt, the parking piston and a guide screw, the limiting bolt is used for compressing the parking piston and is installed on the traveling piston, the guide screw is used for guiding the parking piston and is installed on the traveling piston, and the traveling piston is installed in a brake shell and forms a second oil cylinder with the first sealing ring and the second sealing ring.

Although the brake can simultaneously leak oil from the port A and the port B to press the friction plate group under the action of the parking piston and realize the emergency stop of the pickup truck, some coal mine railcars also need to use the brake, although the brake can also realize the internal leakage when the port A or the port B leaks on the coal mine railcars and can realize the emergency stop by leaking the other port, in the normal use process, the railcar filled with coal has very large kinetic energy in the driving process, when the brake brakes the driving railcar, the friction plate and the dual plate can generate very violent friction, but because the spaces of the friction plate and the dual plate are sealed by a plurality of oil seals and sealing rings, the oil in the cavities of the friction plate and the dual plate avoids the friction plate from being greatly abraded when in use, however, during parking, the friction plate and the dual plate generate huge heat, the temperature in the whole cavity which is provided with the friction plate and the dual plate is obviously increased, the space in the cavity is basically occupied by the friction plate and the dual plate, the storage space of gear oil in the cavity is very small, the temperature of the gear oil is obviously increased after the heat is absorbed by a small amount of gear oil in the cavity, the sealing part is adopted in the sealing cavity to seal the sealing cavity, but when the temperature of the gear oil is too high, the rubber material of the sealing part is easy to deform, and therefore the service life of the sealing part is shortened.

Disclosure of Invention

The utility model aims at having the above-mentioned problem to current technique, provided a braking system's oil circuit structure, the utility model aims to solve the technical problem that: how to solve the problem that the temperature of gear oil in the cavities of the existing dynamic friction plate and static friction plate is too high.

The purpose of the utility model can be realized by the following technical proposal:

an oil path structure of a braking system, the braking system comprises a shaft head, a wheel hub sleeved on the shaft head and a cylinder body sleeved on the wheel hub, an oil cavity is arranged between the shaft head and the wheel hub, the cylinder body is provided with an installation cavity, a transition flange plate, a braking piece arranged on the cylinder body and a friction plate arranged on the wheel hub are arranged in the installation cavity, a first oil inlet channel, a second oil inlet channel, a first piston cavity communicated with the first oil inlet channel and a second piston cavity communicated with the second oil inlet channel are arranged in the cylinder body, and a parking piston is arranged in the second piston cavity. The oil-passing gap between the cylinder body and the transition flange plate is communicated with the oil storage cavity and the mounting cavity, a first gap is formed between the front end of the hub and the side wall of the rear end of the cylinder body, and a first sealing element capable of blocking the first gap is arranged between the cylinder body and the hub.

The working principle is as follows: the brake system is assembled on a coal mine rail car for use, in the use process of the brake system, a mounting cavity, an oil cavity and an oil storage cavity are filled with gear oil, in the starting process of the brake system, oil enters a piston cavity II from an oil inlet channel II and pushes a parking piston in the piston cavity II to move away from a transition flange plate, the transition flange plate moves towards a travelling piston under the action of a return spring, the gear oil in the oil storage cavity between the travelling piston and the transition flange plate flows into the mounting cavity from an oil passing gap under the action of the parking piston and the return spring, the high-temperature gear oil in the mounting cavity can be extruded out of the mounting cavity by the oil in the oil storage cavity due to the high temperature generated by a friction plate and a brake plate in the mounting cavity in time, meanwhile, the gear oil in the oil cavity can be thrown outwards in the rotation process of a hub, and a gap between the front end of the hub and the side wall at the rear end of a cylinder body is sealed by a sealing element, avoid gear oil to flow out from space one for gear oil in the oil chamber is extruded through the oil gallery with the high temperature gear oil between wheel hub and the installation cavity, and the heat of gear oil can be taken away by spindle nose etc. at gear oil circulation in-process, guarantees that the oil temperature in the installation cavity can not be too high, has avoided the oil temperature of gear oil in the installation cavity to influence the sealed effect and the life of sealing member, further promotion the life of sealing member.

In the oil path structure of the braking system, the service piston is annular.

The driving piston adopts the design of ring shape, increased and transition flange disc between area of contact, on the one hand can be quick promote transition flange disc to braking piece compress tightly the friction disc, thereby realize the braking, on the other hand the driving piston leans on the space that can contract the oil storage chamber fast with transition flange disc counterbalance, strengthen the flow velocity of oil storage intracavity fluid, thereby can make the high temperature gear oil outflow installation cavity of the drive installation intracavity that oil storage intracavity fluid can be quick, the oil temperature of the gear oil in the installation cavity has been avoided too high.

In the oil circuit structure of the braking system, a yielding concave cavity is formed in one end, connected with the return spring, of the transition flange plate, and the yielding concave cavity is communicated with the mounting cavity.

The setting of the cavity of stepping down for fluid in the oil storage cavity can be more quick through crossing oily clearance and enter into the cavity of stepping down and the installation cavity, and can slow down the velocity of flow of gear oil through the installation cavity, make the gear oil that the temperature is low can fully contact with braking piece and friction disc, and the heat of taking away is many.

In the oil circuit structure of the braking system, the cylinder body is sleeved at the front end of the wheel hub, and an oil passing space for communicating the oil cavity with the mounting cavity is formed between the transition flange plate and the front end of the wheel hub.

High temperature gear oil in the installation cavity is under the combined action of gear oil in the oil storage cavity and gear oil in the oil cavity, and high temperature gear oil in the installation cavity flows into the oil cavity again through crossing oily space after extruding, and then has reduced the temperature of gear oil in the installation cavity, therefore, gear oil flows through the oil storage cavity in proper order, the installation cavity, cross oily space, the oil cavity and cross the oilhole and then return again in the installation cavity, and gear oil is in the circulation flow state, has avoided the gear oil high temperature in the installation cavity.

In the oil path structure of the braking system, a buffer oil cavity is arranged between the cylinder body and the front end of the wheel hub, the buffer oil cavity is positioned at the rear side of the mounting cavity, and the oil return hole is communicated with the buffer oil cavity.

If the gear oil in the oil cavity is directly thrown into the mounting cavity, the flow speed of the gear oil flowing through the mounting cavity is too high, the gear oil with low temperature cannot be in full contact with the brake disc and the friction disc, and the heat taken away is small; through the setting of this structure, gear oil in the oil cavity is got rid of to the cushion oil intracavity through the oil gallery in, and the gear oil of cushion oil intracavity flows into the installation cavity again, has reduced the velocity of flow of the gear oil flow through the installation cavity that the temperature is low for gear oil that the temperature is low can with braking piece and friction disc fully contact, and the heat of taking away is many.

In the oil circuit structure of the braking system, the cylinder body is connected with a gear ring located in the installation cavity, the braking piece is meshed and fixed with the gear ring, the gear ring is provided with a guide cylinder for the return spring to penetrate through, one end of the guide cylinder is communicated with the installation cavity through the abdicating concave cavity, and a guide gap communicated with the installation cavity is formed between the other end of the guide cylinder and the cylinder body.

The oil in the oil storage cavity flows into the mounting cavity, can flow out from between the brake disc and the friction disc in the mounting cavity, can also flow out from between the brake disc and the cylinder body from the guide gap, and can also flow out from between the brake disc and the transition flange plate, so that the heat driven by each brake disc in the mounting cavity is the same, the condition of partial overheating is avoided, and the stability of the oil circuit circulating system is further improved.

In the oil path structure of the braking system, an annular flange is arranged on the outer peripheral surface of the front end of the hub, an annular cover plate protruding towards the rear end of the cylinder body is arranged on the side wall of the flange, a gap is formed between the inner peripheral surface of the rear end of the cylinder body and the outer peripheral surface of the front end of the hub, a gap is formed between the front end of the annular cover plate and the side wall of the rear end of the cylinder body, the flange, the annular cover plate, the hub and the cylinder body form the buffer oil cavity, and the sealing element is arranged in the buffer oil cavity.

Through the setting of this structure, have interval and the front end of ring apron and the lateral wall of cylinder body rear end between the inner peripheral surface of cylinder body rear end and the outer peripheral face of wheel hub front end and have a space one for wheel hub's rotation does not take place to interfere with the cylinder body, and the sealing member blocks up space one, avoids buffer oil pocket to appear the problem of oil leakage.

In the oil path structure of the braking system, the friction plate is sleeved at the front end of the wheel hub, and the friction plate is connected with the wheel hub through a spline; the brake pad is connected with the cylinder body through a spline, and a second gap is formed between the inner circumferential surface of the brake pad and the front end of the hub.

Through the setting of this structure, through splined connection between friction disc and the wheel hub, there is the gap between friction disc and the wheel hub, has a space two between the inner peripheral surface of braking piece and the front end of wheel hub for gear oil can flow through the installation cavity through these gaps and space two, and then takes away the heat in the installation cavity.

In the oil circuit structure of the braking system, an inner end cover is sleeved on the shaft head and fixedly connected with the cylinder body, the inner end cover is provided with a braking spring and a placing cavity for placing the braking spring, the inner end cover is provided with a first oil inlet communicated with the first oil inlet channel and a second oil inlet communicated with the second oil inlet channel, one end of the parking piston is connected with the braking spring, and the other end of the parking piston extends out of the second piston cavity and abuts against the transition flange plate.

When the braking system needs to drive, gear oil directly enters the oil inlet channel II from the oil inlet II, the oil inlet channel II is communicated with the piston cavity II, the gear oil can push the parking piston to move towards the braking spring, the transition flange plate moves towards the braking spring along with the parking piston under the action of the return spring and gradually approaches to the driving piston, the friction plate is loosened by the braking plate at the moment, and therefore driving is achieved.

Compared with the prior art, the utility model discloses an advantage that braking system's oil circuit structure has: the transition flange plate moves towards the driving piston under the action of the return spring, gear oil in an oil storage cavity between the driving piston and the transition flange plate flows into the installation cavity from an oil passing gap under the action of the parking piston and the return spring, the high temperature generated by a friction plate and a braking plate in the installation cavity is taken away, oil in the oil storage cavity can extrude the high-temperature gear oil in the installation cavity out of the installation cavity in time, meanwhile, the gear oil in the oil cavity can be thrown outwards by the rotating process of the hub, the gap between the front end of the hub and the side wall of the rear end of the cylinder body is blocked by the sealing element, the gear oil is prevented from flowing out of the gap, the oil temperature in the installation cavity is ensured not to be too high, the sealing effect and the service life of the sealing element are prevented from being influenced by the oil temperature of the gear oil in the installation cavity, and the service life of the sealing element is further prolonged.

Drawings

Fig. 1 is a sectional view of an oil path structure of the present brake system.

Fig. 2 is a partially enlarged view of a portion a in fig. 1.

FIG. 3 is an exploded view of the transition flange and service piston of the oil circuit configuration of the present brake system.

In the figure, 1, a shaft head; 2. a hub; 2a, friction plates; 2b, an oil return hole; 2c, a flange; 2d, a circular ring cover plate; 4. a cylinder body; 4a, a first oil inlet channel; 4b, a piston cavity I; 4c, an oil inlet channel II; 4d, a piston cavity II; 4e, mounting a cavity; 5. an oil chamber; 6. a transition flange plate; 6a, yielding concave cavities; 7. a ring gear; 7a, a brake pad; 7b, a guide cylinder; 7c, a guide gap; 8. a traveling piston; 9. an oil storage chamber; 10. an oil passing gap; 11. a return spring; 12. an oil passing space; 13. a buffer oil cavity; 14. spacing; 15. a first gap; 16. a seal member; 17. a second gap; 18. an inner end cap; 18a, a brake spring; 18b, a placing cavity; 18c, a first oil inlet; 18d, a second oil inlet; 19. a parking piston.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

As shown in FIG. 1, the oil path structure of the braking system comprises a shaft head 1, a hub 2 sleeved on the shaft head 1, and a cylinder body 4 sleeved on the hub 2.

Specifically, as shown in fig. 1-3, an oil chamber 5 is provided between a spindle head 1 and a hub 2, a cylinder body 4 is provided with a mounting chamber 4e, a transition flange 6, a brake pad 7a arranged on the cylinder body 4 and a friction plate 2a arranged on the hub 2 are arranged in the mounting chamber 4e, a first oil inlet passage 4a, a second oil inlet passage 4c, a first piston chamber 4b communicated with the first oil inlet passage 4a and a second piston chamber 4d communicated with the oil inlet passage 4c are arranged in the cylinder body 4, a parking piston 19 is arranged in the second piston chamber 4d, a traveling piston 8 is arranged in the first piston chamber 4b, the oil path structure comprises an oil return hole 2b positioned between the mounting chamber 4e and the oil chamber 5, the oil return hole 2b is arranged on the hub 2, an oil storage chamber 9 is arranged between the transition flange 6 and the traveling piston 8, the transition flange 6 is connected with the cylinder body 4 through a return spring 11, an oil passing gap 10 communicating the oil storage chamber 9 and the mounting chamber 4e is arranged between the cylinder body 4 and the transition flange 6, a gap I15 is formed between the front end of the hub 2 and the side wall of the rear end of the cylinder body 4, a sealing piece 16 capable of sealing the gap I15 is arranged between the cylinder body 4 and the hub 2, and the traveling crane piston 8 is in a ring shape.

The working principle is as follows: the brake system is assembled on a coal mine rail car for use, in the use process of the brake system, a mounting cavity 4e, an oil cavity 5 and an oil storage cavity 9 are filled with gear oil, in the starting process of the brake system, the oil enters a piston cavity two 4d from an oil inlet channel two 4c and pushes a parking piston 19 in the piston cavity two 4d to move away from a transition flange 6, at the moment, the transition flange 6 moves towards a driving piston 8 under the action of a return spring 11, the gear oil in the oil storage cavity 9 between the driving piston 8 and the transition flange 6 flows into the mounting cavity 4e from an oil passing gap 10 under the action of the parking piston 19 and the return spring 11, the high temperature generated by a friction plate 2a and a brake plate 7a in the mounting cavity 4e is taken away, the high temperature gear oil in the mounting cavity 4e can be timely extruded out of the mounting cavity 4e by the oil in the oil storage cavity 9, and the gear oil in the oil cavity 5 can be thrown outwards in the rotation process of a hub 2, and a 15 clearance between the lateral wall of wheel hub 2's front end and cylinder body 4 rear end passes through sealing member 16 shutoff, avoid gear oil to flow out in a 15 clearance, make the gear oil in the oil pocket 5 pass through oil gallery 2b and be extruded the high temperature gear oil between wheel hub 2 and installation cavity 4e, the heat of gear oil can be taken away by spindle nose 1 etc. in gear oil circulation process, guarantee that the oil temperature in the installation cavity 4e can not be too high, the oil temperature of the gear oil in installation cavity 4e influence the sealed effect and the life of sealing member 16, further promotion the life of sealing member 16.

As shown in fig. 1 and 2, a return spring 11 is connected to the transition flange 6, one end of the return spring 11 is connected to the cylinder body 4, an abdicating cavity 6a is formed in one end of the transition flange 6, which is connected to the return spring 11, and the abdicating cavity 6a is communicated with the installation cavity 4 e.

As shown in fig. 2, the cylinder body 4 is sleeved at the front end of the hub 2, an oil passing space 12 for communicating the oil cavity 5 with the mounting cavity 4e is arranged between the transition flange 6 and the front end of the hub 2, a buffer oil cavity 13 is arranged between the cylinder body 4 and the front end of the hub 2, the buffer oil cavity 13 is positioned at the rear side of the mounting cavity 4e, and the oil return hole 2b is communicated with the buffer oil cavity 13.

As shown in fig. 2, the cylinder 4 is connected with a gear ring 7 located in the mounting cavity 4e, the brake pad 7a is meshed and fixed with the gear ring 7, the gear ring 7 is provided with a guide cylinder 7b through which a return spring 11 can penetrate, one end of the guide cylinder 7b is communicated with the mounting cavity 4e through a yielding cavity 6a, and a guide gap 7c communicated with the mounting cavity 4e is arranged between the other end of the guide cylinder 7b and the cylinder 4.

As shown in fig. 2, the outer peripheral surface of the front end of the hub 2 is provided with an annular flange 2c, the side wall of the flange 2c is provided with an annular cover plate 2d protruding towards the rear end of the cylinder 4, the inner peripheral surface of the rear end of the cylinder 4 and the inner peripheral surface of the annular cover plate 2d are provided with a gap 14 with the outer peripheral surface of the front end of the hub 2, a gap 15 is formed between the front end of the annular cover plate 2d and the side wall of the rear end of the cylinder 4, a buffer oil cavity 13 is formed by the flange 2c, the annular cover plate 2d, the hub 2 and the cylinder 4, a sealing element 16 is arranged in the buffer oil cavity 13, and the sealing element 16 is a floating oil seal.

As shown in fig. 2, the friction plate 2a is sleeved on the front end of the hub 2, and the friction plate 2a is connected with the hub 2 through a spline; the brake disc 7a is connected to the cylinder 4 by a spline, and a second gap 17 is provided between the inner peripheral surface of the brake disc 7a and the front end of the hub 2.

As shown in fig. 1, an inner end cap 18 is sleeved on the spindle head 1, the inner end cap 18 is fixedly connected with the cylinder body 4, the inner end cap 18 is provided with a brake spring 18a and a placing cavity 18b for placing the brake spring 18a, the inner end cap 18 is provided with a first oil inlet 18c communicated with the first oil inlet channel 4a and a second oil inlet 18d communicated with the second oil inlet channel 4c, one end of a parking piston 19 is connected with the brake spring 18a, and the other end of the parking piston 19 extends out of the second piston cavity 4d and abuts against the transition flange 6.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims

1. An oil circuit structure of a braking system comprises a shaft head (1), a hub (2) sleeved on the shaft head (1) and a cylinder body (4) sleeved on the hub (2), wherein an oil cavity (5) is formed between the shaft head (1) and the hub (2), the cylinder body (4) is provided with a mounting cavity (4e), a transition flange plate (6), a braking plate (7a) arranged on the cylinder body (4) and a friction plate (2a) arranged on the hub (2) are arranged in the mounting cavity (4e), a first oil inlet channel (4a), a second oil inlet channel (4c), a first piston cavity (4b) communicated with the first oil inlet channel (4a) and a second piston cavity (4d) communicated with the second oil inlet channel (4c) are arranged in the cylinder body (4), a piston (19) is arranged in the second piston cavity (4d), and a traveling piston (8) is arranged in the first piston cavity (4b), this oil circuit structure is including being located oil gallery (2b) between installation cavity (4e) and oil pocket (5), oil gallery (2b) are seted up on wheel hub (2), oil storage chamber (9) have between transition ring flange (6) and driving piston (8), be connected through return spring (11) between transition ring flange (6) and cylinder body (4), oil clearance (10) of crossing that have intercommunication oil storage chamber (9) and installation cavity (4e) between cylinder body (4) and transition ring flange (6), space (15) have between the front end of wheel hub (2) and the lateral wall of cylinder body (4) rear end, be equipped with sealing member (16) that can shutoff space (15) between cylinder body (4) and wheel hub (2).

2. An oil circuit arrangement of a brake system according to claim 1, characterized in that the traveling piston (8) is annular.

3. The oil circuit structure of the brake system according to claim 1, wherein an abdicating concave cavity (6a) is formed at one end of the transition flange (6) connected with the return spring (11), and the abdicating concave cavity (6a) is communicated with the mounting cavity (4 e).

4. The oil circuit structure of a brake system as claimed in any one of claims 1 to 3, wherein the cylinder body (4) is sleeved on the front end of the hub (2), and an oil passing space (12) for communicating the oil cavity (5) with the mounting cavity (4e) is arranged between the transition flange plate (6) and the front end of the hub (2).

5. The oil circuit structure of a brake system according to any one of claims 1 to 3, wherein a buffer oil chamber (13) is provided between the cylinder block (4) and the front end of the wheel hub (2), the buffer oil chamber (13) is located at the rear side of the mounting chamber (4e), and the oil return hole (2b) is communicated with the buffer oil chamber (13).

6. The oil circuit structure of a brake system according to claim 3, wherein a gear ring (7) located in the installation cavity (4e) is connected to the cylinder body (4), the brake disc (7a) is meshed and fixed with the gear ring (7), the gear ring (7) is provided with a guide cylinder (7b) through which a return spring (11) can penetrate, one end of the guide cylinder (7b) is communicated with the installation cavity (4e) through a yielding cavity (6a), and a guide gap (7c) communicated with the installation cavity (4e) is formed between the other end of the guide cylinder (7b) and the cylinder body (4).

7. The oil circuit structure of a brake system according to claim 5, wherein the outer peripheral surface of the front end of the wheel hub (2) is provided with a flange (2c) in a ring shape, the side wall of the flange (2c) is provided with an annular cover plate (2d) protruding towards the rear end of the cylinder body (4), the inner peripheral surface of the annular cover plate (2d) and the outer peripheral surface of the front end of the wheel hub (2) are provided with a gap (14), the flange (2c), the annular cover plate (2d), the wheel hub (2) and the cylinder body (4) form the buffer oil cavity (13), and the sealing element (16) is arranged in the buffer oil cavity (13).

8. The oil circuit structure of the brake system according to any one of claims 1 to 3, wherein the friction plate (2a) is sleeved on the front end of the hub (2), and the friction plate (2a) is connected with the hub (2) through a spline; the brake disc (7a) is connected with the cylinder (4) through a spline, and a second gap (17) is formed between the inner circumferential surface of the brake disc (7a) and the front end of the hub (2).

9. The oil circuit structure of the brake system according to any one of claims 1 to 3, wherein an inner end cap (18) is sleeved on the spindle head (1), the inner end cap (18) is fixedly connected with the cylinder body (4), the inner end cap (18) is provided with a brake spring (18a) and a placing cavity (18b) for placing the brake spring (18a), the inner end cap (18) is provided with a first oil inlet (18c) communicated with the first oil inlet channel (4a) and a second oil inlet (18d) communicated with the second oil inlet channel (4c), one end of the parking piston (19) is connected with the brake spring (18a), and the other end of the parking piston (19) extends out of the second piston cavity (4d) and abuts against the transition flange (6).