An active hydraulic brake cylinder with clearance adjustment function

Abstract

This invention relates to an active hydraulic brake cylinder with clearance adjustment function, comprising a cylinder body, a piston, a drive shaft, and a clearance adjustment ring. The cylinder body has an internal cylinder cavity with an opening at one axial end. A stop sleeve is installed at the opening. A piston is located within the cylinder cavity, dividing the cylinder cavity into a first oil chamber and a second oil chamber. A drive shaft is located within the second oil chamber, with one end connected to the piston and the other end extending out of the cylinder body via the stop sleeve. A clearance adjustment ring is mounted on the drive shaft, allowing axial movement within the second oil chamber along with the drive shaft. The ring is also limited by the stop sleeve, resulting in axial deformation. This invention achieves braking, brake release, and clearance adjustment functions by changing the oil pressure on both sides of the piston. The overall structure is simple, highly integrated and modular, with rapid braking response, improving braking sensitivity and driving safety.

Description

Technical Field

[0001] This invention belongs to the field of braking technology for rail transit vehicles, and particularly relates to an active hydraulic brake cylinder with clearance adjustment function. Background Technology

[0002] With the rapid development of rail transit technology, the types of rail vehicles are increasing, and vehicle bogies are developing towards lightweight and compact designs. Compared with pneumatic braking systems, hydraulic braking systems have advantages such as compact structure, small size, light weight, and high braking power, and are therefore used in low-floor trams, straddle-type monorail vehicles, maglev trains, and other rail vehicles.

[0003] In existing hydraulic basic braking technology, the drawback of active hydraulic brake cylinders without gap adjustment function is that, in the released state, the brake pads of hydraulic brake calipers without automatic reset function can move along the brake pad mounting axis. This movement may cause the brake pads and brake discs to be misaligned, resulting in brake pad wear, metal embedding in the brake disc, and sparks between them during operation. Furthermore, when the hydraulic pressure is initially released, the brake pads may be close to or loosely attached to the brake disc, increasing friction and wear between the brake pads and the brake disc. On the other hand, hydraulic brake calipers with automatic reset function become thinner as the brake pads wear down, leading to longer braking response time and excessive braking distance, which affects driving safety.

[0004] For active hydraulic brake cylinders that can achieve gap adjustment, there are some existing designs. For example, Chinese invention patent CN115978113A discloses an active hydraulic brake caliper with automatic brake pad gap adjustment function. It uses a return spring and a rectangular spring to automatically generate a set gap, realizing the separation of the brake pad and brake disc after the brake is released. However, the hydraulic brake cylinder still has the problems of complex structure and high requirements for spring performance. Summary of the Invention

[0005] The purpose of this invention is to solve one of the above-mentioned technical problems and to provide an active hydraulic brake cylinder with clearance adjustment function.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An active hydraulic brake cylinder with clearance adjustment function includes a cylinder body, a cylinder cavity inside the cylinder body, an opening at one end of the cylinder body in the axial direction, and a stop sleeve installed at the opening.

[0008] A piston is installed inside the cylinder cavity. The piston is coaxial with the main axis of the cylinder body. The piston seals the cylinder cavity radially and can move relative to the cylinder cavity. The piston divides the cylinder cavity into a first oil chamber and a second oil chamber.

[0009] The second oil chamber is equipped with a drive shaft. One end of the drive shaft is fixedly connected to the piston, and the end of the drive shaft away from the piston extends out of the cylinder body through the stop sleeve.

[0010] The cylinder body is provided with a first oil passage communicating with the first oil chamber and a second oil passage communicating with the second oil chamber;

[0011] A clearance adjusting ring is provided on the drive shaft. The clearance adjusting ring can move axially with the drive shaft in the second oil chamber and can be blocked and limited by the stop sleeve, resulting in axial elastic deformation.

[0012] This technical solution solves the problems of existing active hydraulic brake cylinders with gap adjustment function having complex structure, high requirements for spring performance, and unstable gap adjustment effect. It can achieve the effects of braking, brake release and gap adjustment by changing the oil pressure on both sides of the piston.

[0013] In some embodiments of the present invention, a plurality of lugs protruding radially from the inner wall of the cylinder body at the second oil cavity are provided, and the plurality of lugs are evenly distributed circumferentially on the inner wall of the cylinder body; the gap adjusting ring is provided between the lugs and the stop sleeve, and can be blocked and limited by the lugs.

[0014] In some embodiments of the present invention, the gap adjusting ring is interference-fitted onto the drive shaft, and the gap adjusting ring has radial elasticity.

[0015] In some embodiments of the present invention, the frictional force between the gap adjusting ring and the drive shaft is less than the piston thrust generated by the hydraulic pressure applied during braking, and the frictional force between the gap adjusting ring and the drive shaft is greater than the piston thrust generated by the hydraulic pressure applied during braking release.

[0016] In some embodiments of the present invention, a plurality of sealing grooves are provided on the inner wall of the cylinder between the piston and the cylinder body, and a sealing element is installed in each sealing groove. The sealing element is used to achieve sealing between the cylinder body and the piston and / or to guide the piston.

[0017] In some embodiments of the present invention, a cylinder bushing hole is provided on the cylinder body, and a cylinder bushing is interference-fitted into the cylinder bushing hole; an air passage is provided on the cylinder body, and the air passage connects the outside atmosphere and the cylinder bushing hole.

[0018] In some embodiments of the present invention, one end of the drive shaft extending out of the cylinder body is connected to a cover assembly, the cover assembly having a cover bushing hole, and a cover bushing being interference-fitted into the cover bushing hole.

[0019] In some embodiments of the present invention, a first sealing element for sealing is provided between the stop sleeve and the cylinder body.

[0020] In some embodiments of the present invention, a second sealing element for sealing and a guide ring for guiding the drive shaft are provided between the stop sleeve and the drive shaft.

[0021] In some embodiments of the present invention, a dust cover is provided between the cylinder body and the extended end of the transmission shaft. One end of the dust cover is connected to the outer wall of the cylinder body, and the other end is connected to the transmission shaft.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention achieves automatic gap adjustment function through the cooperation of gap adjustment ring, ear seat and stop sleeve, which can adjust the gap between brake pad and brake disc; during braking, when the brake pad is worn, the piston in the hydraulic brake cylinder moves more, which can quickly compensate for the increase in braking stroke caused by brake pad and brake disc wear or other factors, the braking response is rapid, and the braking sensitivity and driving safety are improved.

[0024] 2. The gap adjustment mechanism of the present invention eliminates the traditional structure of disc spring energy storage and relief and oil-filled braking. The braking, braking relief and gap compensation functions can be realized by the oil pressure on both sides of the piston and the oil pressure magnitude. The overall structure is simple, with few parts and a high degree of integration and modularity.

[0025] 3. This invention can adjust the brake pad opening degree of the brake caliper mechanism and set the brake pad gap by changing the oil pressure of the oil chambers on both sides of the piston and setting the position of the gap adjustment ring on the transmission shaft, which facilitates brake pad replacement and subsequent maintenance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a structure with an active hydraulic brake cylinder.

[0028] Figure 2 This is an enlarged view of part A in the structural schematic diagram of a hydraulic brake cylinder with active braking.

[0029] Wherein, λ is the rated retraction distance of the gap adjusting ring;

[0030] The attached figures are labeled as follows:

[0031] 1. Cylinder body; 11. Cylinder bushing hole; 12. Cylinder bushing; 13. Air passage; 14. Sealing groove; 15. Ear seat; 16. First oil passage; 17. Second oil passage; 2. Piston; 31. First oil chamber; 32. Second oil chamber; 4. Drive shaft; 5. Gap adjusting ring; 6. First seal; 7. Stop sleeve; 8. Guide ring; 9. Second seal; 10. Cover assembly; 101. Cover bushing; 102. Cover bushing hole; 11. Dust cover. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0033] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without any creative effort.

[0034] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0035] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] As attached Figure 1 - Appendix Figure 2As shown, in an illustrative embodiment of an active hydraulic brake cylinder with clearance adjustment function according to the present invention, the active hydraulic brake cylinder with clearance adjustment function includes a cylinder body 1, the cylinder body 1 has a cylinder cavity inside, one end of the cylinder body 1 in the axial direction is provided with an opening, a stop sleeve 7 is installed at the opening, the stop sleeve 7 and the cylinder body 1 are connected together by threads and are sealed to prevent oil leakage.

[0038] A piston 2 is provided inside the cylinder cavity. The piston 2 includes a piston head and a piston rod. The piston head and piston rod are cylindrical with a stepped shape. The piston 2 is coaxial with the main axis of the cylinder body 1. The piston 2 radially closes the cylinder cavity and can move relative to the cylinder cavity. The piston head part with a larger diameter is in contact with the inner wall of the cylinder body 1. The piston 2 divides the cylinder cavity into a first oil chamber 31 and a second oil chamber 32.

[0039] The second oil chamber 32 is equipped with a drive shaft 4 for transmitting braking force. One end of the drive shaft 4 is fixedly connected to the piston 2. Specifically, the drive shaft 4 and the piston rod of the piston 2 are connected by threads, and the diameter of the drive shaft and the piston rod of the piston 2 are the same. The end of the drive shaft 4 away from the piston 2 extends out of the cylinder body 1 through the stop sleeve 7, and the drive shaft 4 and the stop sleeve 7 are sealed to prevent oil leakage.

[0040] The cylinder body 1 is provided with a first oil passage 16 connected to the first oil chamber 31 for applying hydraulic pressure to push the piston 2 toward the stop sleeve 7 for braking, and a second oil passage 17 connected to the second oil chamber 32 for applying hydraulic pressure to push the piston 2 away from the stop sleeve 7 for braking relief.

[0041] A clearance adjusting ring 5 is provided on the drive shaft 4. The clearance adjusting ring 5 has friction with the drive shaft 4, allowing it to move axially within the second oil chamber 32 along with the drive shaft 4. It can also be stopped and limited by the stop sleeve 7, resulting in axial elastic deformation. Specifically, the clearance adjusting ring 5 is made of high-strength, high-stress elastic rubber. During braking, after being stopped and limited by the stop sleeve 7, the clearance adjusting ring 5 remains in its original position. Under the hydraulic pressure within the first oil chamber 31, the drive shaft 4 can continue to move relative to the clearance adjusting ring 5.

[0042] In the above illustrative embodiment, the active hydraulic brake cylinder has an automatic gap adjustment function. By changing the oil pressure on both sides of the piston 2 and the oil pressure magnitude, braking, brake release, and automatic gap adjustment can be achieved, which can achieve the effects of rapid braking response, improved braking sensitivity, and improved driving safety.

[0043] In some embodiments of the present invention, a plurality of lugs 15 protruding radially from the inner wall of the cylinder body 1 at the second oil chamber 32 are provided, and the plurality of lugs 15 are evenly distributed circumferentially on the inner wall of the cylinder body 1; in this embodiment, three lugs 15 are evenly distributed circumferentially on the inner wall of the cylinder body 1; the gap adjusting ring 5 is disposed between the lugs 15 and the stop sleeve 7, and can be blocked and limited by the lugs 15 when the brake is released. When the position of the gap adjusting ring 5 on the transmission shaft 7 is adjusted by the oil pressure on both sides of the piston 2, the gap adjusting ring 5 can remain in its original position after being blocked and limited by the lugs 15, and under the hydraulic pressure in the second oil chamber 32, the transmission shaft 4 can continue to move relative to the gap adjusting ring 5.

[0044] It is understandable that by using the ear seat 15 and the stop sleeve 7 to limit the movement of the clearance adjusting ring 5, the different hydraulic pressures in the oil chambers on both sides of the piston 2 can achieve braking, brake release, and clearance compensation functions. At the same time, the position of the clearance adjusting ring 5 on the transmission shaft 4 can be adjusted by changing the magnitude of the hydraulic pressure on both sides of the piston 2, thereby adjusting the brake pad opening degree of the brake caliper mechanism and setting the brake pad clearance, which facilitates the maintenance and replacement of the brake pads. It can also prevent the clearance adjusting ring 5 from moving axially along the transmission shaft 4 and coming off during operation.

[0045] The movable distance of the gap adjusting ring 5 between the lug 15 and the stop sleeve 7 is the rated retraction distance λ of the gap adjusting ring 5. The distance between the lug 15 and the stop sleeve 7, as well as the rated retraction distance λ of the gap adjusting ring 5, can be set according to the requirements of the brake pad clearance. When the brake pad clearance is ζ, the rated retraction distance λ of the gap adjusting ring 5 is approximately ζ + 1.5. It should be noted that since rail vehicles preferentially use electric braking, the speed is already low when hydraulic braking is applied, so the wear between the brake pad and the brake disc is very small. During braking, the frictional movement distance of the gap adjusting ring 5 relative to the drive shaft 4 after moving the rated retraction distance λ is very short.

[0046] It should be noted that the maximum movement distance of piston 2 is the distance between the end of piston 2 away from the first oil chamber and the ear seat 15 in the brake release state. The maximum adjustment amount of the active hydraulic brake cylinder is the same as the maximum movement distance of piston 2. The single adjustment amount of the active hydraulic brake cylinder is the same as the brake pad gap, but does not exceed the maximum adjustment amount of the active hydraulic brake cylinder.

[0047] In some embodiments of the present invention, the gap adjusting ring 5 is interference-fitted to the drive shaft 4. Specifically, the inner hole of the gap adjusting ring 5 is interference-fitted to the outer cylindrical surface of the drive shaft 4. There is friction between the gap adjusting ring 5 and the drive shaft 4. At the same time, since the gap adjusting ring 5 itself has radial elasticity, it is not easy to slide relative to the drive shaft 4.

[0048] Furthermore, the frictional force between the gap adjusting ring 5 and the drive shaft 4 is less than the piston thrust generated by the hydraulic pressure applied during braking, and the frictional force between the gap adjusting ring 5 and the drive shaft 4 is greater than the piston thrust generated by the hydraulic pressure applied during brake release.

[0049] In some embodiments of the present invention, a plurality of sealing grooves 14 are formed on the inner wall of the cylinder body 1 between the piston 2 and the cylinder body 1. Each sealing groove 14 is equipped with a sealing element, which is used to achieve sealing between the cylinder body 1 and the piston 2 and / or guide the piston 2. It should be noted that when the piston 2 moves axially within the cylinder cavity, the sealing groove 14 is always located between the cylinder cavity and the piston 2. In this embodiment, two sealing grooves 14 are formed on the cylinder body 1, namely a guide ring mounting groove and a sealing ring mounting groove. The sealing element installed in the guide ring mounting groove is a guide ring, and the sealing element installed in the sealing ring mounting groove is an O-ring.

[0050] In some embodiments of the present invention, a cylinder bushing hole 11 is provided on the cylinder body 1, and a cylinder bushing 12 is interference-fitted into the cylinder bushing hole 11. The cylinder bushing 12 is pressed into the cylinder bushing hole 11 and integrated with the cylinder body 1. The cylinder bushing 12 and the cylinder bushing hole 11 are interference-fitted and used to connect with the brake caliper lever. In this embodiment, two pairs of cylinder bushings 12 and cylinder bushing holes 11 are provided. The two cylinder bushing holes 11 are arranged vertically coaxially and symmetrically on the cylinder body 1.

[0051] Furthermore, the cylinder bushing hole 11 can be a cylindrical hole or a cylindrical stepped hole. Correspondingly, the cylinder bushing 12 can be a cylindrical structure or a stepped cylindrical structure with a flange. It can be understood that the shape of the cylinder bushing hole 11 matches the structure of the cylinder bushing 12.

[0052] Furthermore, an air passage 13 is provided on the cylinder body 1. The air passage 13 connects the cylinder bushing hole 11 with the outside atmosphere. When the cylinder bushing 12 is pressed into the cylinder bushing hole 11, the air in the cylinder bushing hole 11 is discharged through the air passage 13. Specifically, the air passage 13 is a small-diameter circular channel.

[0053] In some embodiments of the present invention, one end of the drive shaft 4 extending out of the cylinder body 1 is connected to a cover assembly 10 for transmitting braking force. The drive shaft 4 and the cover assembly 10 are fastened together by bolts. The cover assembly 10 has a cover bushing hole 102. A cover bushing 101 is interference-fitted into the cover bushing hole 102. The cover bushing 101 is pressed into the cover bushing hole 102 and integrated with the cover assembly 10. The cover bushing 101 and the cover bushing hole 102 are interference-fitted and used to connect with the brake caliper lever. In this embodiment, two pairs of cover bushings 101 and cover bushing holes 102 are provided. The two cover bushing holes 102 are arranged vertically coaxially and symmetrically on the cover assembly 10.

[0054] Furthermore, the cover bushing hole 102 can be a cylindrical hole or a cylindrical stepped hole. Correspondingly, the cover bushing 101 can be a cylindrical structure or a stepped cylindrical structure with a flange. It can be understood that the shape of the cover bushing hole 102 matches the structure of the cover bushing 101.

[0055] In some embodiments of the present invention, a first sealing element 6 is provided between the stop sleeve 7 and the cylinder body 1 and on the side close to the cylinder cavity, for sealing between the stop sleeve 7 and the cylinder body 1 to prevent oil leakage during braking and braking release. Specifically, the first sealing element 6 is an O-ring.

[0056] In some embodiments of the present invention, a guide ring 8 for guiding and a second sealing element 9 for sealing are provided between the stop sleeve 7 and the drive shaft 4. Specifically, the second sealing element 9 is an O-ring. Furthermore, a dustproof sealing ring can be added to one end of the stop sleeve 7 near the cover assembly 10 to prevent external dust and water stains from entering and contaminating the internal moving mechanism.

[0057] In some embodiments of the present invention, a dust cover 11 is provided between the cylinder body 1 and the extended end of the transmission shaft 4. One end of the dust cover 11 is connected to the outer wall of the cylinder body 1, and the other end is connected to the transmission shaft 4, in order to further prevent external dust and water stains from entering and contaminating the internal moving mechanism.

[0058] The working principle of this invention is explained in detail below:

[0059] When braking under normal clearance conditions, hydraulic oil is added to the first oil chamber 31 through the first oil passage 16. The hydraulic pressure in the first oil chamber 31 generates piston thrust on the piston 2 in the cylinder cavity, pushing the piston 2, drive shaft 4 and clearance adjusting ring 5 together to move towards the stop sleeve 7. After moving the rated back distance λ, the clearance adjusting ring 5 and the stop sleeve 7 are tightly attached. At this time, the brake pad is attached to the brake disc. Since the clearance adjusting ring 5 can generate axial elastic deformation, the piston 2 and drive shaft 4 continue to move for one axial elastic deformation e displacement and then stop moving. The brake pad is tightly attached to the brake disc, generating braking force.

[0060] When braking with a worn gap in the brake pads, hydraulic oil is added to the first oil chamber 31 through the first oil passage 16. The hydraulic pressure in the first oil chamber 31 generates a piston thrust on the piston 2 in the cylinder cavity, pushing the piston 2, drive shaft 4, and gap adjusting ring 5 together towards the stop sleeve 7. After moving the rated retraction distance λ, the gap adjusting ring 5 and the stop sleeve 7 are tightly pressed together. Blocked by the stop sleeve 7, the gap adjusting ring 5 can no longer move. Since the wear thickness of the brake pads exceeds the axial elastic deformation of the gap adjusting ring 5, the piston 2 and drive shaft 4 continue to move forward after moving a displacement e. At this time, the piston thrust generated by the hydraulic pressure in the first oil chamber 31 is greater than the frictional force generated by the radial elastic force of the gap adjusting ring 5. The piston 2 and drive shaft 4 continue to move forward until the brake pads are pressed against the brake disc to generate braking force. Since the gap adjusting ring 5 has radial elastic force, it can be repositioned on the drive shaft 4 when the axial piston thrust is less than the frictional force.

[0061] When the brakes are released, the piston thrust generated by the hydraulic pressure in the first oil chamber 31 quickly dissipates. Simultaneously, hydraulic oil is added to the second oil chamber 32 through the second oil passage 17. The hydraulic pressure in the second oil chamber 32 generates piston thrust on the piston 2 in the cylinder cavity, pushing the piston 2, drive shaft 4, and clearance adjusting ring 5 together to move away from the stop sleeve 7. After moving the rated retraction distance λ, the clearance adjusting ring 5 is tightly pressed against the lug 15. Blocked by the lug 15, the clearance adjusting ring 5 can no longer move, and the piston 2 and drive shaft 4 also stop moving. At this time, the distance between the clearance adjusting ring 5 and the stop sleeve 7 remains at the rated retraction distance λ, that is, the set position is reached, and the brake pad also reaches the position where it maintains a normal clearance with the brake disc. The clearance compensation action is completed. It should be noted that the piston thrust F generated by the hydraulic pressure loaded in the second oil chamber 32 during brake release should be less than the frictional force F between the clearance adjusting ring 5 and the drive shaft 4. S That is, F < F S .

[0062] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. An active hydraulic brake cylinder with a gap adjustment function, characterized by, The oil cylinder body is internally provided with an oil cylinder cavity, and an opening is arranged at one end of the oil cylinder body in the axial direction, and a stop sleeve is arranged at the opening; The oil cylinder cavity is provided with a piston, the piston is coaxially arranged with the main axis of the oil cylinder body, the piston radially seals the oil cylinder cavity, and the piston can move relative to the oil cylinder cavity; The piston divides the oil cylinder cavity into a first oil cavity and a second oil cavity; The second oil cavity is provided with a transmission shaft, one end of the transmission shaft is fixedly connected with the piston, and the other end of the transmission shaft away from the piston extends out of the oil cylinder body through the stop sleeve; The oil cylinder body is provided with a first oil channel communicated with the first oil cavity and a second oil channel communicated with the second oil cavity; The transmission shaft is provided with a gap adjusting ring made of elastic rubber material, the gap adjusting ring is interference connected on the transmission shaft, has radial elastic force, the gap adjusting ring can move axially in the second oil cavity with the transmission shaft, and can be blocked and limited by the stop sleeve to generate axial elastic deformation; A plurality of lug seats protruding in the radial direction of the oil cylinder body are arranged on the inner wall of the oil cylinder body at the second oil cavity, and the plurality of lug seats are uniformly distributed on the inner wall of the oil cylinder body in the circumferential direction; the gap adjusting ring is arranged between the lug seat and the stop sleeve and can be blocked and limited by the lug seat; The friction force between the gap adjusting ring and the transmission shaft is less than the piston thrust generated by the hydraulic pressure loaded in the braking process, and the friction force between the gap adjusting ring and the transmission shaft is greater than the piston thrust generated by the hydraulic pressure loaded in the braking relief process.

2. The gap-adjustable active hydraulic brake cylinder according to claim 1, characterized in that A plurality of sealing grooves are arranged on the inner wall of the cylinder between the piston and the oil cylinder body, and a sealing element is arranged in each sealing groove, which is used for sealing and / or guiding the piston.

3. The gap-adjustable active hydraulic brake cylinder according to claim 1, characterized in that An oil cylinder bush hole is arranged on the oil cylinder body, and an oil cylinder bush is interference connected in the oil cylinder bush hole; an air passage is arranged on the oil cylinder body, and the air passage is communicated with the outside air and the oil cylinder bush hole.

4. The gap-adjustable active hydraulic brake cylinder according to claim 1, characterized in that A cover body is connected to the end of the transmission shaft extending out of the oil cylinder body, a cover body bush hole is arranged on the cover body, and a cover body bush is interference connected in the cover body bush hole.

5. The gap-adjustable active hydraulic brake cylinder according to claim 1, wherein A first sealing element for sealing is arranged between the stop sleeve and the oil cylinder body.

6. The gap-adjustable active hydraulic brake cylinder according to claim 1, wherein A second sealing element for sealing and a guide ring for guiding the transmission shaft are arranged between the stop sleeve and the transmission shaft.

7. The gap-adjustable active hydraulic brake cylinder according to claim 1, wherein A dust cover is arranged between the oil cylinder body and the extended end of the transmission shaft, one end of the dust cover is connected to the outer wall of the oil cylinder body, and the other end of the dust cover is connected to the transmission shaft.

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