An oil circuit structure of a braking system

Abstract

The present invention provides an oil circuit structure of a braking system, belonging to the technical field of brakes. It solves the problem of excessively high oil temperature of the gear oil in the chambers of the dynamic friction plate and the static friction plate in the existing braking system. For the oil circuit structure of this braking system, the braking system includes a spindle head, a hub sleeved on the spindle head, and a cylinder block sleeved on the hub. There is an oil chamber between the spindle head and the hub. The cylinder block has an installation cavity, in which there is a transition flange, a brake pad arranged on the cylinder block, and a friction plate arranged on the hub. The cylinder block has an oil inlet passage one, an oil inlet passage two, a piston chamber one communicated with the oil inlet passage one, and a piston chamber two communicated with the oil inlet passage two. A parking piston is arranged in the piston chamber two, and a service piston is arranged in the piston chamber one. This oil circuit structure includes an oil return hole located between the installation cavity and the oil chamber. The oil return hole is opened on the hub, and there is an oil storage cavity between the transition flange and the service piston. The oil circuit structure of this braking system can improve the service life of the sealing elements.

Description

Technical Field

[0001] The present invention belongs to the technical field of brakes, and particularly relates to an oil circuit structure of a braking system. Background Art

[0002] During the process of coal mining, rail vehicles are usually used to transport the coal in the mine to the outside of the mine. After the coal is piled on the rail vehicle, the weight of the rail vehicle is very heavy. When the rail vehicle travels to the outside of the mine, it is necessary to brake the rail vehicle. Since the rail vehicle has a very large kinetic energy after traveling, a hydraulic brake is generally configured on the rail vehicle to brake the rail vehicle.

[0003] The existing braking system, such as the Chinese Patent Application [Publication Number: CN204284256U], discloses a double-acting wet hydraulic brake for a pickup truck, which includes a brake housing connected to the pickup truck axle housing. The brake housing includes a first sealing ring and a second sealing ring, and the first sealing ring and the second sealing ring are installed in the grooves of the brake housing. It also includes a brake seat, and the brake seat includes a friction plate, a first oil seal for sealing the oil in the brake oil chamber, and a first screw. The friction plate is connected to the brake seat through a spline and can move axially relative to the brake seat. The brake seat is connected to the pickup truck half shaft through the first screw. It also includes an internal gear ring, and the internal gear ring includes a pair of coupling plates. The internal gear ring is connected to the brake housing through a second screw. The pair of coupling plates are connected through a spline internal gear ring and can move axially relative to each other. It also includes a flange cover, and the flange cover includes a second oil seal. The flange cover is connected to the internal gear ring through a third screw. The second oil seal is used to seal the oil in the brake oil chamber. It also includes a parking piston, and the parking piston includes a third sealing ring, a fourth sealing ring, and a parking piston. The third sealing ring and the fourth sealing ring are installed in the grooves of the parking piston. The parking piston is installed in the internal gear ring and forms a first oil cylinder with the third sealing ring and the fourth sealing ring. It also includes a service piston, and the service piston includes a limit bolt, a parking piston, and a guide screw. The limit bolt is used to compress the parking piston and is installed on the service piston. The guide screw is used to guide the parking piston and is installed on the service piston. The service piston is installed in the brake housing and forms a second oil cylinder with the first sealing ring and the second sealing ring.

[0004] Although the above-mentioned brake can simultaneously internally drain the hydraulic fluid from ports A and B in case of an emergency, enabling the parking piston and the service piston to press the friction plate group under the action of the parking piston and achieving an emergency stop of the pickup truck, some coal mine railcars also need to use brakes. Although the above-mentioned brake can also achieve an emergency stop by internally draining the other port when port A or port B experiences internal leakage during the movement of the coal mine railcar, during normal use, a fully loaded coal mine railcar has a very large kinetic energy during travel. When the brake brakes the moving railcar, extremely intense friction will occur between the friction plate and the mating plate. However, since the space where the friction plate and the mating plate are located is sealed by multiple oil seals and sealing rings, the hydraulic fluid in the chamber where the friction plate and the mating plate are located prevents the friction plate from experiencing significant wear during use. However, when parking, a huge amount of heat is generated between the friction plate and the mating plate, resulting in a significant increase in the temperature of the entire chamber containing the friction plate and the mating plate. Since the space in the chamber is basically occupied by the friction plate and the mating plate, the storage space for the gear oil in the chamber is very small. After the heat is absorbed by the small amount of gear oil in the chamber, the temperature of the gear oil rises significantly. The sealing chamber is sealed with a seal, but when the temperature of the gear oil is too high, the rubber material of the seal is prone to deformation, thereby reducing the service life of the seal. Summary of the Invention

[0005] The object of the present invention is to address the above problems existing in the prior art and propose an oil circuit structure for a braking system. The technical problem to be solved by the present invention is: how to solve the problem of excessive oil temperature of the gear oil in the chambers of the existing dynamic friction plate and static friction plate.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] An oil circuit structure for a braking system, the braking system includes an axle head, a hub sleeved on the axle head, and a cylinder body sleeved on the hub. There is an oil chamber between the axle head and the hub. The cylinder body has an installation chamber. The installation chamber has a transition flange, a brake pad provided on the cylinder body, and a friction plate provided on the hub. The cylinder body has an oil inlet passage 1, an oil inlet passage 2, a piston chamber 1 communicated with the oil inlet passage 1, and a piston chamber 2 communicated with the oil inlet passage 2. A parking piston is provided in the piston chamber 2. It is characterized in that a service piston is provided in the piston chamber 1. This oil circuit structure includes an oil return hole located between the installation chamber and the oil chamber. The oil return hole is opened on the hub. There is an oil storage chamber between the transition flange and the service piston. The transition flange and the cylinder body are connected by a return spring. There is an oil passing gap between the cylinder body and the transition flange that communicates the oil storage chamber and the installation chamber. There is a gap 1 between the front end of the hub and the side wall of the rear end of the cylinder body. A seal is provided between the cylinder body and the hub to block the gap 1.

[0008] Working principle: This braking system is assembled on a coal mine rail vehicle. During the use of the braking system, the installation cavity, the oil cavity, and the oil storage cavity are all filled with gear oil. During the startup process of the braking system, the oil fluid enters the piston cavity two through the second oil inlet passage and pushes the parking piston in the piston cavity two to move away from the transition flange. At this time, the transition flange moves towards the traveling piston under the action of the return spring. The gear oil in the oil storage cavity between the traveling piston and the transition flange flows into the installation cavity from the oil passing gap under the action of the parking piston and the return spring, taking away the high temperature generated by the friction plates and brake pads in the installation cavity. The oil fluid in the oil storage cavity can timely squeeze out the high temperature gear oil in the installation cavity. At the same time, during the rotation of the wheel hub, the gear oil in the oil cavity is thrown outwards. The gap one between the front end of the wheel hub and the side wall at the rear end of the cylinder block is sealed by a seal to prevent the gear oil from flowing out of the gap one, so that the gear oil in the oil cavity is squeezed out of the high temperature gear oil between the wheel hub and the installation cavity through the oil return hole. During the circulation of the gear oil, the heat of the gear oil can be taken away by the shaft head and other parts, ensuring that the oil temperature in the installation cavity will not be too high, avoiding the influence of the oil temperature of the gear oil in the installation cavity on the sealing effect and service life of the seal, and further improving the service life of the seal.

[0009] In the oil circuit structure of the above-mentioned braking system, the traveling piston is in an annular shape.

[0010] The traveling piston is designed in an annular shape, increasing the contact area with the transition flange. On the one hand, it can quickly push the transition flange to press the brake pads against the friction plates, thereby achieving braking. On the other hand, the traveling piston abuts against the transition flange, which can quickly contract the space of the oil storage cavity, enhancing the flow rate of the oil fluid in the oil storage cavity, so that the oil fluid in the oil storage cavity can quickly drive the high temperature gear oil in the installation cavity out of the installation cavity, avoiding the oil temperature of the gear oil in the installation cavity from being too high.

[0011] In the oil circuit structure of the above-mentioned braking system, a relief concave cavity is provided at one end of the transition flange connected to the return spring, and the relief concave cavity is communicated with the installation cavity.

[0012] The setting of the relief concave cavity enables the oil fluid in the oil storage cavity to enter the relief concave cavity and the installation cavity more quickly through the oil passing gap, and can slow down the flow rate of the gear oil flowing through the installation cavity, so that the gear oil with a lower temperature can fully contact the brake pads and friction plates and take away more heat.

[0013] In the oil circuit structure of the above-mentioned braking system, the cylinder block is sleeved on the front end of the wheel hub, and there is an oil passing space communicating the oil cavity with the installation cavity between the transition flange and the front end of the wheel hub.

[0014] Under the combined action of the gear oil in the oil storage cavity and the gear oil in the oil cavity, the high-temperature gear oil in the installation cavity is extruded and then flows back into the oil cavity through the oil passage space, thereby reducing the temperature of the gear oil in the installation cavity. Therefore, the gear oil flows through the oil storage cavity, the installation cavity, the oil passage space, the oil cavity and the oil hole in sequence and then returns to the installation cavity again. The gear oil is in a circulating flow state, avoiding the overheating of the gear oil in the installation cavity.

[0015] In the oil circuit structure of the above-mentioned braking system, there is a buffer oil cavity between the front end of the cylinder block and the hub. The buffer oil cavity is located at the rear side of the installation cavity, and the oil return hole is communicated with the buffer oil cavity.

[0016] If the gear oil in the oil cavity is directly thrown into the installation cavity, the flow rate of the gear oil flowing through the installation cavity will be too fast, and the gear oil with a low temperature cannot fully contact the brake pads and friction pads, taking away less heat. Through the setting of this structure, the gear oil in the oil cavity is thrown into the buffer oil cavity through the oil return hole, and the gear oil in the buffer oil cavity then flows into the installation cavity, reducing the flow rate of the gear oil with a low temperature flowing through the installation cavity, so that the gear oil with a low temperature can fully contact the brake pads and friction pads and take away more heat.

[0017] In the oil circuit structure of the above-mentioned braking system, a gear ring located in the installation cavity is connected to the cylinder block. The brake pad is meshed and fixed with the gear ring. The gear ring has a guide cylinder through which the return spring can pass. One end of the guide cylinder is communicated with the installation cavity through a relief cavity, and there is a guide gap communicated with the installation cavity between the other end of the guide cylinder and the cylinder block.

[0018] The oil fluid in the oil storage cavity flows into the installation cavity, and can flow out between the brake pads and friction pads in the installation cavity, or can enter and flow out between the brake pad and the cylinder block through the guide gap, or can also flow out between the brake pad and the transition flange. This makes the heat driven by each brake pad in the installation cavity the same, avoiding the situation of partial overheating, and further improving the stability of the oil circuit circulation system.

[0019] In the oil circuit structure of the above-mentioned braking system, there is an annular flange on the outer peripheral surface of the front end of the hub. There is a circular ring cover plate protruding towards the rear end of the cylinder block on the side wall of the flange. There are gaps between the inner peripheral surface of the rear end of the cylinder block, the inner peripheral surface of the circular ring cover plate and the outer peripheral surface of the front end of the hub. There is a gap one between the front end of the circular ring cover plate and the side wall of the rear end of the cylinder block. The flange, the circular ring cover plate, the hub and the cylinder block form the buffer oil cavity, and the seal is arranged in the buffer oil cavity.

[0020] With the setting of this structure, there is a spacing between the inner peripheral surface at the rear end of the cylinder block and the outer peripheral surface at the front end of the hub, and there is a gap I between the front end of the circular ring cover plate and the side wall at the rear end of the cylinder block, so that the rotation of the hub does not interfere with the cylinder block, and the sealant seals the gap I to avoid oil leakage in the buffer oil chamber.

[0021] The sealant is the sealant

[0022] In the oil circuit structure of a braking system described above, the friction plate is sleeved on the front end of the hub, and the friction plate and the hub are connected by a spline; the brake pad and the cylinder block are connected by a spline, and there is a gap II between the inner peripheral surface of the brake pad and the front end of the hub.

[0023] With the setting of this structure, the friction plate and the hub are connected by a spline, there is a gap between the friction plate and the hub, and there is a gap II between the inner peripheral surface of the brake pad and the front end of the hub, so that the gear oil can flow through the installation cavity through these gaps and the gap II, thereby taking away the heat in the installation cavity.

[0024] In the oil circuit structure of the braking system described above, an inner end cover is sleeved on the shaft head, the inner end cover is fixedly connected to the cylinder block, the inner end cover has a brake spring and a placement cavity for placing the brake spring, the inner end cover has an oil inlet I communicating with the oil inlet passage I and an oil inlet II communicating with the oil inlet passage II, one end of the parking piston is connected to the brake spring, and the other end of the parking piston extends out of the piston cavity II and abuts against the transition flange.

[0025] When the braking system needs to drive, directly enter the gear oil from the oil inlet II into the oil inlet passage II. The oil inlet passage II communicates with the piston cavity II, and the gear oil can push the parking piston to move towards the brake spring. Under the action of the return spring, the transition flange also moves towards the brake spring with the parking piston and gradually approaches the driving piston. At this time, the brake pad releases the friction plate, thereby realizing driving. Since driving is completed under the combined force of the parking piston and the return spring, the driving of the braking system is more convenient and stable.

[0026] Compared with the prior art, the oil circuit structure of the braking system of the present invention has the following advantages: The transition flange moves towards the service piston under the action of the return spring, and the gear oil in the oil storage cavity between the service piston and the transition flange flows into the installation cavity from the oil passing gap under the action of the parking piston and the return spring, taking away the high temperature generated by the friction plates and brake pads in the installation cavity. The oil in the oil storage cavity can timely squeeze out the high-temperature gear oil in the installation cavity. At the same time, during the rotation of the hub, the gear oil in the oil cavity is thrown outwards. The gap between the front end of the hub and the side wall at the rear end of the cylinder block is sealed by a seal to prevent the gear oil from flowing out of the gap, ensuring that the oil temperature in the installation cavity will not be too high, avoiding the influence of the oil temperature of the gear oil in the installation cavity on the sealing effect and service life of the seal, and further improving the service life of the seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a cross-sectional view of the oil circuit structure of the present braking system.

[0028] Figure 2 is Figure 1 the partial enlarged view at A in

[0029] Figure 3 an exploded view of the transition flange and the service piston in the oil circuit structure of the present braking system.

[0030] In the figure, 1, axle head; 2, hub; 2a, friction plate; 2b, oil return hole; 2c, flange; 2d, circular ring cover plate; 4, cylinder block; 4a, first oil inlet passage; 4b, first piston cavity; 4c, second oil inlet passage; 4d, second piston cavity; 4e, installation cavity; 5, oil cavity; 6, transition flange; 6a, relief cavity; 7, gear ring; 7a, brake pad; 7b, guide tube; 7c, guide gap; 8, service piston; 9, oil storage cavity; 10, oil passing gap; 11, return spring; 12, oil passing space; 13, buffer oil cavity; 14, spacing; 15, gap one; 16, seal; 17, gap two; 18, inner end cover; 18a, brake spring; 18b, placement cavity; 18c, first oil inlet; 18d, second oil inlet; 19, parking piston. DETAILED DESCRIPTION OF THE INVENTION

[0031] The following are specific embodiments of the present invention in combination with the drawings, and the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0032] As Figure 1 shown, for the oil circuit structure of the present braking system, the braking system includes an axle head 1, a hub 2 sleeved on the axle head 1, and a cylinder block 4 sleeved on the hub 2.

[0033] Specifically, as Figures 1 - 3As shown, there is an oil cavity 5 between the shaft head 1 and the hub 2. The cylinder block 4 has an installation cavity 4e. Inside the installation cavity 4e, there is a transition flange 6, a brake pad 7a provided on the cylinder block 4, and a friction plate 2a provided on the hub 2. Inside the cylinder block 4, there are an oil inlet passage 4a, an oil inlet passage 4c, a piston cavity 4b communicating with the oil inlet passage 4a, and a piston cavity 4d communicating with the oil inlet passage 4c. A parking piston 19 is provided in the piston cavity 4d, and a service piston 8 is provided in the piston cavity 4b. This oil circuit structure includes an oil return hole 2b located between the installation cavity 4e and the oil cavity 5. The oil return hole 2b is opened on the hub 2. There is an oil storage cavity 9 between the transition flange 6 and the service piston 8. The transition flange 6 and the cylinder block 4 are connected by a return spring 11. There is an oil passing gap 10 between the cylinder block 4 and the transition flange 6 that communicates the oil storage cavity 9 and the installation cavity 4e. There is a gap 15 between the front end of the hub 2 and the side wall of the rear end of the cylinder block 4. A seal 16 is provided between the cylinder block 4 and the hub 2 to block the gap 15. The service piston 8 is annular.

[0034] Working principle: This braking system is assembled on a coal mine rail vehicle for use. During the use of the braking system, the installation cavity 4e, the oil cavity 5, and the oil storage cavity 9 are all filled with gear oil. During the startup process of the braking system, the oil fluid enters the piston cavity 4d from the oil inlet passage 4c and pushes the parking piston 19 in the piston cavity 4d to move away from the transition flange 6. At this time, the transition flange 6 moves towards the service piston 8 under the action of the return spring 11. The gear oil in the oil storage cavity 9 between the service piston 8 and the transition flange 6 flows into the installation cavity 4e from the oil passing gap 10 under the action of the parking piston 19 and the return spring 11, taking away the high temperature generated by the friction plate 2a and the brake pad 7a in the installation cavity 4e. And the oil fluid in the oil storage cavity 9 can timely squeeze out the high-temperature gear oil in the installation cavity 4e from the installation cavity 4e. At the same time, during the rotation of the hub 2, the gear oil in the oil cavity 5 will be thrown outwards. And the gap 15 between the front end of the hub 2 and the side wall of the rear end of the cylinder block 4 is blocked by the seal 16 to prevent the gear oil from flowing out from the gap 15, so that the gear oil in the oil cavity 5 is squeezed out of the high-temperature gear oil between the hub 2 and the installation cavity 4e through the oil return hole 2b. During the circulation of the gear oil, the heat of the gear oil can be taken away by the shaft head 1, etc., ensuring that the oil temperature in the installation cavity 4e will not be too high, avoiding the influence of the oil temperature of the gear oil in the installation cavity 4e on the sealing effect and service life of the seal 16, and further improving the service life of the seal 16.

[0035] As Figure 1 and Figure 2 shown, a return spring 11 is connected to the transition flange 6. One end of the return spring 11 is connected to the cylinder block 4. The end of the transition flange 6 connected to the return spring 11 is provided with a relief cavity 6a, and the relief cavity 6a communicates with the installation cavity 4e.

[0036] AsFigure 2 As shown, the cylinder block 4 is sleeved on the front end of the hub 2. There is an oil passage space 12 communicating the oil chamber 5 and the installation chamber 4e between the transition flange 6 and the front end of the hub 2. There is a buffer oil chamber 13 between the cylinder block 4 and the front end of the hub 2. The buffer oil chamber 13 is located at the rear side of the installation chamber 4e, and the oil return hole 2b communicates with the buffer oil chamber 13.

[0037] As Figure 2 shown, a gear ring 7 located in the installation chamber 4e is connected to the cylinder block 4. The brake pad 7a is meshed and fixed with the gear ring 7. The gear ring 7 has a guide cylinder 7b through which the return spring 11 can pass. One end of the guide cylinder 7b communicates with the installation chamber 4e through a relief cavity 6a, and there is a guide gap 7c communicating with the installation chamber 4e between the other end of the guide cylinder 7b and the cylinder block 4.

[0038] As Figure 2 shown, an annular flange 2c is provided on the outer peripheral surface of the front end of the hub 2. A circular ring cover plate 2d protruding towards the rear end of the cylinder block 4 is provided on the side wall of the flange 2c. There is a spacing 14 between the inner peripheral surface of the rear end of the cylinder block 4, the inner peripheral surface of the circular ring cover plate 2d and the outer peripheral surface of the front end of the hub 2. There is a gap one 15 between the front end of the circular ring cover plate 2d and the side wall of the rear end of the cylinder block 4. The buffer oil chamber 13 is formed by the flange 2c, the circular ring cover plate 2d, the hub 2 and the cylinder block 4. A seal 16 is arranged in the buffer oil chamber 13, and the seal 16 is a floating oil seal.

[0039] As Figure 2 shown, the friction plate 2a is sleeved on the front end of the hub 2, and the friction plate 2a is connected to the hub 2 through a spline; the brake pad 7a is connected to the cylinder block 4 through a spline, and there is a gap two 17 between the inner peripheral surface of the brake pad 7a and the front end of the hub 2.

[0040] As Figure 1 shown, an inner end cover 18 is sleeved on the shaft head 1. The inner end cover 18 is fixedly connected to the cylinder block 4. The inner end cover 18 has a brake spring 18a and a placement cavity 18b for placing the brake spring 18a. The inner end cover 18 has an oil inlet one 18c communicating with the first oil inlet passage 4a and an oil inlet two 18d communicating with the second oil inlet passage 4c. One end of the parking piston 19 is connected to the brake spring 18a, and the other end of the parking piston 19 extends out of the second piston chamber 4d and abuts against the transition flange 6.

[0041] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An oil circuit structure of a braking system. The braking system includes an axle head (1), a hub (2) sleeved on the axle head (1), and a cylinder block (4) sleeved on the hub (2). There is an oil chamber (5) between the axle head (1) and the hub (2). The cylinder block (4) has an installation cavity (4e). Inside the installation cavity (4e), there is a transition flange (6), a brake pad (7a) provided on the cylinder block (4), and a friction plate (2a) provided on the hub (2). Inside the cylinder block (4), there are an oil inlet passage one (4a), an oil inlet passage two (4c), a piston chamber one (4b) communicated with the oil inlet passage one (4a), and a piston chamber two (4d) communicated with the oil inlet passage two (4c). A parking piston (19) is provided in the piston chamber two (4d). Characterized in that, A service piston (8) is provided in the piston chamber one (4b). This oil circuit structure includes an oil return hole (2b) located between the installation cavity (4e) and the oil chamber (5). The oil return hole (2b) is opened on the hub (2). There is an oil storage cavity (9) between the transition flange (6) and the service piston (8). The transition flange (6) and the cylinder block (4) are connected by a return spring (11). There is an oil passing gap (10) between the cylinder block (4) and the transition flange (6) that communicates the oil storage cavity (9) and the installation cavity (4e). There is a gap one (15) between the front end of the hub (2) and the side wall of the rear end of the cylinder block (4). A seal (16) capable of blocking the gap one (15) is provided between the cylinder block (4) and the hub (2).

2. An oil circuit structure of a braking system according to claim 1, Characterized in that, The service piston (8) is in an annular shape.

3. An oil circuit structure of a braking system according to claim 1, Characterized in that, A relief cavity (6a) is opened at one end of the transition flange (6) connected to the return spring (11). The relief cavity (6a) communicates with the installation cavity (4e).

4. An oil circuit structure of a braking system according to any one of claims 1 to 3, Characterized in that, The cylinder block (4) is sleeved on the front end of the hub (2). There is an oil passing space (12) between the transition flange (6) and the front end of the hub (2) that communicates the oil chamber (5) and the installation cavity (4e).

5. An oil circuit structure of a braking system according to any one of claims 1 to 3, Characterized in that, There is a buffer oil chamber (13) between the cylinder block (4) and the front end of the hub (2). The buffer oil chamber (13) is located at the rear side of the installation cavity (4e), and the oil return hole (2b) is communicated with the buffer oil chamber (13).

6. An oil circuit structure of a braking system according to claim 3, Characterized in that, A ring gear (7) located within the installation cavity (4e) is connected to the cylinder block (4). The brake pad (7a) is fixedly engaged with the ring gear (7). The ring gear (7) has a guide cylinder (7b) through which the return spring (11) can pass. One end of the guide cylinder (7b) communicates with the installation cavity (4e) through a relief cavity (6a), and there is a guide gap (7c) communicating with the installation cavity (4e) between the other end of the guide cylinder (7b) and the cylinder block (4).

7. The oil circuit structure of a braking system according to any one of claims 1 to 3, characterized in that, An annular flange (2c) is provided on the outer peripheral surface at the front end of the hub (2). A circular ring cover plate (2d) protruding towards the rear end of the cylinder block (4) is provided on the side wall of the flange (2c). There is a gap (14) between the inner peripheral surface at the rear end of the cylinder block (4), the inner peripheral surface of the circular ring cover plate (2d), and the outer peripheral surface at the front end of the hub (2). The flange (2c), the circular ring cover plate (2d), the hub (2), and the cylinder block (4) form the buffer oil cavity (13), and the seal (16) is arranged within the buffer oil cavity (13).

8. The oil circuit structure of a braking system according to any one of claims 1 to 3, characterized in that, The friction plate (2a) is sleeved on the front end of the hub (2), and the friction plate (2a) is connected to the hub (2) through a spline connection; the brake pad (7a) is connected to the cylinder block (4) through a spline connection, and there is a second gap (17) between the inner peripheral surface of the brake pad (7a) and the front end of the hub (2).

9. The oil circuit structure of a braking system according to any one of claims 1 to 3, characterized in that, An inner end cover (18) is sleeved on the axle head (1). The inner end cover (18) is fixedly connected to the cylinder block (4). The inner end cover (18) has a brake spring (18a) and a placement cavity (18b) for placing the brake spring (18a). The inner end cover (18) has an oil inlet one (18c) communicating with the first oil inlet passage (4a) and an oil inlet two (18d) communicating with the second oil inlet passage (4c). One end of the parking piston (19) is connected to 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).

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