Height-adjustable shock absorber

Abstract

The utility model relates to the technical field of automobile shock absorbers, in particular to a height-adjustable shock absorber which comprises a shock absorption spring, a damper, an automobile body connecting seat and a chassis connecting seat, the damper comprises a cylinder body and a piston body, the chassis connecting seat is of an encircling structure and forms a sliding cavity, and the chassis connecting seat is arranged on the cylinder body in a sleeved mode through the sliding cavity. At least one fastening assembly is arranged on the chassis connecting base in the circumferential direction, each fastening assembly comprises a fixing sleeve, a reset spring and a fastening plug pin arranged in the fixing sleeve in a sliding mode, the two ends of each fixing sleeve are arranged in a penetrating mode, the two ends of each fastening plug pin extend out of the two ends of the corresponding fixing sleeve respectively, and penetrating holes corresponding to the fixing sleeves are formed in the chassis connecting base. A positioning hole is formed in the outer wall of the cylinder body, and the reset spring makes contact with the fixing sleeve and the fastening plug pin so as to drive the fastening plug pin to penetrate through the penetrating hole and be matched with the positioning hole. The height of the shock absorber can be adjusted, and the connection firmness degree of the chassis connecting base and the cylinder body is improved.

Description

Technical Field

[0001] This utility model relates to the field of automotive shock absorber technology, specifically to a height-adjustable shock absorber. Background Technology

[0002] Automotive shock absorbers consist of springs and dampers. Dampers are used to suppress the oscillations caused by the springs absorbing shocks and the impacts from the road surface. Widely used in automobiles, shock absorbers reduce vibrations between the chassis and body, improving ride comfort. In racing cars or high-end passenger vehicles, shock absorbers often require different installation heights to adjust the vehicle's ride height for different road conditions; for example, the vehicle needs to be raised for off-road driving and lowered for city driving.

[0003] Vehicle height adjustment is achieved by adjusting the shock absorbers. There are two types: full-length adjustable and non-full-length adjustable. The former adjusts the height of the lower mounting bracket of the shock absorber, while the latter uses a preload spring. Since the preload spring reduces the shock absorber's travel and affects its performance, the full-length adjustable type is preferable. One existing full-length adjustable shock absorber features a semi-enclosed lower mounting bracket fitted around the cylinder body. This semi-enclosed structure creates a side opening with two connecting parts. These two parts are bolted together to secure the lower mounting bracket to the cylinder body. Furthermore, the contact surfaces between the lower mounting bracket and the cylinder body are relatively fixed using anti-slip protrusions and grooves. In the prior art, when the position of the lower fixed seat needs to be adjusted, the bolts must first be removed so that the lower fixed seat is no longer clamped to the cylinder body and the anti-slip protrusion is dislodged from the anti-slip groove before the lower fixed seat can be moved. However, the lower fixed seat itself is a rigid component, so the deformation of the lower fixed seat is not significant in both the case of bolt tightening and loosening. Therefore, the mating depth between the anti-slip protrusion and the anti-slip groove needs to be shallow so that they can disengage when the bolt is loose, thus meeting the needs of adjusting the position of the lower fixed seat.

[0004] In other words, the existing technology has a locking structure in the circumferential direction of the lower fixed seat. However, it is not a completely enclosed structure in the circumferential direction, which has weak points. Furthermore, due to the limitations of the locking structure of the lower fixed seat, the mating depth of the anti-slip protrusions and anti-slip grooves between the lower fixed seat and the cylinder is relatively shallow. The relative fixation between the lower fixed seat and the cylinder is relatively weak. When the shock absorber is subjected to a large impact, it may cause relative movement between the lower fixed seat and the cylinder, which may not only cause a sudden change in the vehicle height but also pose a safety hazard. Utility Model Content

[0005] The purpose of this utility model is to provide a solution that solves the problem of weak connection between the chassis connecting seat and the damper cylinder. The chassis connecting seat is a fully enclosed, circumferentially enveloping structure that is fitted onto the cylinder with a sliding cavity. The chassis connecting seat is positioned and fixed by the fastening pin of the fastening assembly, so that the chassis connecting seat always tightly envelops the cylinder. The mating depth between the fastening pin and the positioning hole is not limited by the structure of the chassis connecting seat. Thus, while ensuring that the height of the chassis connecting seat is adjustable, the connection between the chassis connecting seat and the cylinder is strengthened.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: a height-adjustable shock absorber, comprising a shock-absorbing spring, a damper, a body connecting seat, and a chassis connecting seat. The damper includes a cylinder and a piston. The body connecting seat is fixed to the upper end of the piston. The chassis connecting seat is located at the lower end of the cylinder. The chassis connecting seat has a ring-shaped structure and forms a sliding cavity. The chassis connecting seat is sleeved on the cylinder through the sliding cavity. At least one fastening component is provided circumferentially on the chassis connecting seat. The fastening component includes a fixed sleeve, a return spring, and a fastening pin slidably disposed within the fixed sleeve. Both ends of the fixed sleeve are through-holes. Both ends of the fastening pin extend beyond both ends of the fixed sleeve. The chassis connecting seat has a through hole corresponding to the fixed sleeve. The outer wall of the cylinder has a positioning hole. The return spring contacts the fixed sleeve and the fastening pin respectively to drive the fastening pin through the through hole and engage with the positioning hole.

[0007] In one embodiment, the fastening pin is arranged perpendicular to the axial direction of the cylinder body, or the fastening pin is arranged obliquely upward from the end away from the cylinder body to the end near the cylinder body.

[0008] In one embodiment, the end of the fastening pin that is away from the cylinder extends out of the fixing sleeve and is fixed with a pull head, the diameter of which is larger than the diameter of the fastening pin.

[0009] In one embodiment, the chassis connecting seat is provided with at least one row of fastening components arranged along the cylinder axial direction, and the pull heads located in the same row are all fixedly connected to a linkage rod so as to drive the fastening pins in the same row to move simultaneously through the linkage rod.

[0010] In one embodiment, a plurality of reinforcing airbags are provided between the cylinder body and the chassis connecting seat, and the reinforcing airbags cooperate with the cylinder body and the chassis connecting seat respectively to fix the chassis connecting seat and the cylinder body relatively.

[0011] In one embodiment, a first connecting groove is provided on the wall of the sliding cavity, a second connecting groove is provided on the outer wall of the cylinder body, the reinforcing airbag is fixedly connected to the first connecting groove, and an air hole is provided on the chassis connecting seat, the air hole communicating with the first connecting groove, so as to inflate and deflate the reinforcing airbag through the air hole.

[0012] In one embodiment, the chassis connecting seat is provided with an air passage, and the outer wall of the chassis connecting seat is provided with a main opening. The air passage is connected to each of the air holes, and the main opening is connected to the air passage, so as to simultaneously inflate and deflate each of the reinforcing airbags.

[0013] In one embodiment, the chassis connecting seat is provided with an air passage, and the outer wall of the chassis connecting seat is provided with a main opening. The air passage is connected to each of the air holes, and the main opening is connected to the air passage, so as to simultaneously inflate and deflate each of the reinforcing airbags.

[0014] In one embodiment, a sliding groove is provided on the wall surface of the sliding cavity, and a sliding rib is provided on the outer wall of the cylinder body. Both the sliding groove and the sliding rib extend along the cylinder body axial direction, and the sliding rib slides in conjunction with the sliding groove.

[0015] The advantages of this application compared to the prior art are:

[0016] In this embodiment, a chassis connecting seat for a height-adjustable shock absorber is provided. Firstly, a sliding cavity that fully surrounds the cylinder body in the circumferential direction ensures the chassis connecting seat's structure is robust and stable, eliminating weak points in the circumferential direction and strongly preventing axial misalignment between the chassis connecting seat and the cylinder body, thus improving the relative stability between them. Furthermore, in embodiments where the sliding cavity wall is tightly fitted to the outer wall of the cylinder body, the friction between them is increased, further enhancing the axial fixation effect. Secondly, a fastening pin of the fastening assembly is inserted into a positioning hole to achieve axial positioning between the chassis connecting seat and the cylinder body. Unlocking is achieved simply by pulling the fastening pin, facilitating adjustment of the chassis connecting seat's position on the cylinder body. The fastening pin's unlocking relies on its own sliding within the fixed sleeve, without requiring the sliding cavity wall to detach from the outer wall of the cylinder body. Therefore, the engagement depth between the fastening pin and the positioning hole can be relatively deep, further increasing the relative fixation strength between the chassis connecting seat and the cylinder body. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of a height-adjustable shock absorber according to an embodiment of this application;

[0019] Figure 2 This is a cross-sectional plan view of the chassis connecting seat and the cylinder block in an embodiment of this application;

[0020] Figure 3 This is a top view of the chassis connecting seat in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of a column of fastening components according to an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of a reinforcing airbag provided between the cylinder block and the chassis connection seat in an embodiment of this application;

[0023] Figure 6 This is a schematic diagram of a column of reinforced airbags in the deflated state in an embodiment of this application. Detailed Implementation

[0024] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0025] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of this application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0027] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0028] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings.

[0029] Please refer to Figure 1This application embodiment provides a height-adjustable shock absorber comprising a shock-absorbing spring 100, a damper 200, a body connecting seat 300, and a chassis connecting seat 400. The damper 200 includes a cylinder 210 and a piston 220. The body connecting seat 300 is fixed to the upper end of the piston 220 for connecting to the vehicle body. The chassis connecting seat 400 is located at the lower end of the cylinder 210 for connecting to the chassis (such as a steering knuckle). It should be noted that the orientation descriptions in this application specification are based on the shock absorber being placed vertically, with the body connecting seat 300 at the upper end and the chassis connecting seat 400 at the lower end. The axis of the shock absorber is the vertical direction.

[0030] Please refer to Figure 2 , Figure 3The difference between this embodiment and the prior art is that, on the one hand, the chassis connecting seat 400 has an encircling structure and forms a sliding cavity 410. The encircling structure is a structure that completely surrounds the sliding cavity 410 in the circumferential direction, and its specific shape is not limited. The sliding cavity 410 is vertically connected, so that the chassis connecting seat 400 is fitted onto the cylinder body 210 through the sliding cavity 410. In this way, the chassis connecting seat 400 completely surrounds the cylinder body 210 in the circumferential direction. The chassis connecting seat 400 itself does not have an opening and closing structure, which ensures the structural strength of the chassis connecting seat 400 itself. Preferably, the wall surface of the sliding cavity 410 in the chassis connecting seat 400 is tightly attached to the outer wall of the cylinder body 210, so that the chassis connecting seat 400 itself is tightly clamped. On the other hand, the chassis connecting seat 400 is provided with at least one fastening component 500 in the circumferential direction. The fastening component 500 includes a fixing sleeve 510, a return spring 520, and a fastening pin 530 slidably disposed in the fixing sleeve 510. Both ends of the fixing sleeve 510 are through-holes, and both ends of the fastening pin 530 extend out of both ends of the fixing sleeve 510. The chassis connecting seat 400 is provided with a through hole 420 corresponding to the fixing sleeve 510, and the outer wall of the cylinder body 210 is provided with a positioning hole 211. The return spring 520 contacts the fixing sleeve 510 and the fastening pin 530 respectively, so as to drive the fastening pin 530 through the through hole 420 and close to the cylinder body 210. The positioning hole 211 engages, thus fixing the cylinder body 210 and the chassis connecting seat 400 relative to each other via the fastening pin 530. When the height of the chassis connecting seat 400 needs to be adjusted, force is applied to the end of the fastening pin 530 away from the cylinder body 210, overcoming the force of the return spring 520 to pull the fastening pin 530 outward, causing the end of the fastening pin 530 near the cylinder body 210 to disengage from the positioning hole 211. Then the position of the chassis connecting seat 400 can be adjusted. When the chassis connecting seat 400 is adjusted to a certain position, the fastening pin 530 is released, and the return spring 520 presses the fastening pin 530 into the corresponding positioning hole 211, fixing the chassis connecting seat 400 in that position. Specifically, the fixing sleeve 510 has a first flange, the fastening pin 530 has a second flange, and the return spring 520 is disposed between the first flange and the second flange, thereby pushing the fastening pin 530 to move relative to the fixing sleeve 510.

[0031] In summary, the chassis connecting seat 400 of the height-adjustable shock absorber in this embodiment of the application, on the one hand, is made structurally robust and stable by the circumferentially enclosed sliding cavity 410 fitted onto the cylinder body 210, eliminating weak points in the circumferential direction and strongly preventing axial misalignment between the chassis connecting seat 400 and the cylinder body 210, thereby improving the relative stability between the chassis connecting seat 400 and the cylinder body 210. Furthermore, in embodiments where the wall of the sliding cavity 410 is tightly fitted to the outer wall of the cylinder body 210, the friction between the two is also increased, further enhancing the relative fixation effect in the axial direction; on the other hand, through... The fastening pin 530 of the fastening assembly 500 is inserted into the positioning hole 211 to achieve axial positioning between the chassis connecting seat 400 and the cylinder 210. It can be unlocked simply by pulling the fastening pin 530, which makes it easy to adjust the position of the chassis connecting seat 400 on the cylinder 210. The unlocking of the fastening pin 530 is achieved by sliding itself in the fixing sleeve 510. It does not require the wall of the sliding cavity 410 to detach from the outer wall of the cylinder 210. Therefore, the engagement depth between the fastening pin 530 and the positioning hole 211 can be relatively deep, thereby further increasing the relative fixation between the chassis connecting seat 400 and the cylinder 210.

[0032] Furthermore, in this embodiment, the fastening pin 530 can be axially arranged perpendicular to the cylinder 210, or the fastening pin 530 can be obliquely upward from the end away from the cylinder 210 to the end near the cylinder 210. In the former embodiment, the fastening pin 530 is subjected to a shear force perpendicular to itself, and the axial relative fixation between the chassis connecting seat 400 and the cylinder 210 mainly relies on the rigidity of the fastening pin 530 itself. In the latter embodiment, the fastening pin 530 is inserted obliquely upward into the positioning hole 211. Since the cylinder 210 has a tendency to press down relative to the chassis connecting seat 400, the positioning hole 211 is fastened from top to bottom at the end of the fastening pin 530, providing an additional locking effect.

[0033] Please refer to Figure 4 In this embodiment, the end of the fastening pin 530 away from the cylinder 210 extends out of the fixed sleeve 510 and is fixed with a pull head 531. The diameter of the pull head 531 is larger than the diameter of the fastening pin 530, which makes it easier for the operator to apply force to the pull head 531, so that the operator can pull the fastening pin 530 away from the cylinder 210 with less effort.

[0034] Furthermore, in a preferred embodiment of this application, the chassis connecting seat 400 is provided with at least one row of fastening components 500 arranged axially along the cylinder body 210, and the pull heads 531 located in the same row are all fixedly connected to a linkage rod 532, so that the linkage rod 532 can simultaneously drive the fastening pins 530 in the same row to move. In this embodiment, the fastening pins 530 located in the same row face the same direction, so the direction of movement when they are pulled back away from the cylinder body 210 to unlock the fastening components 500 is also the same. Therefore, by setting the linkage rod 532, the fastening pins 530 in the same row can be pulled synchronously, saving time and effort. Moreover, setting the linkage rod 532 solves the problem of simultaneously pulling multiple fastening pins 530, thereby allowing multiple fastening components 500 to be set on the chassis connecting seat 400, thereby further improving the relative fixation between the chassis connecting seat 400 and the cylinder body 210. In some embodiments, multiple rows of fastening components 500 may be arranged circumferentially on the chassis connecting seat 400, and each row is provided with a linkage rod 532.

[0035] For further details, please refer to Figure 5 In some embodiments of this application, a plurality of reinforcing airbags 600 are preferably provided between the cylinder body 210 and the chassis connecting seat 400. The reinforcing airbags 600 cooperate with the cylinder body 210 and the chassis connecting seat 400 respectively. In this way, the reinforcing airbags 600 become the snap-fit ​​members between the cylinder body 210 and the chassis connecting seat 400. Under shear force, the relative fixation between the chassis connecting seat 400 and the cylinder body 210 is further improved. When the position of the chassis connecting seat 400 needs to be adjusted, the gas in the reinforcing airbag 600 is released. In this way, the reinforcing airbag 600 no longer acts as an obstacle when moving the chassis connecting seat 400. After the chassis connecting seat 400 has been moved, the reinforcing airbag 600 is inflated again, so that the reinforcing airbag 600 cooperates with both the cylinder 210 and the chassis connecting seat 400, thereby hindering the movement of the chassis connecting seat 400 relative to the cylinder 210. This disperses the pressure on the fastening pin 530, improves the service life of the fastening pin 530, and when the shock absorber is subjected to a sudden strong impact, the reinforcing airbag 600 can also play a buffering role, reducing the instantaneous pressure on the fastening pin 530 and protecting the fastening pin 530.

[0036] In embodiments of this application with a reinforced airbag 600, the reinforced airbag 600 needs to be inflated and deflated. One implementation involves providing an inflation / deflation channel between the cylinder 210 and the chassis connecting seat 400. However, this would disrupt the tight fit between the outer wall of the cylinder 210 and the wall of the sliding cavity 410. Therefore, please refer to... Figure 6In this preferred embodiment, the sliding cavity 410 has a first connecting groove 610 on its wall, and the cylinder 210 has a second connecting groove 620 on its outer wall. The reinforcing airbag 600 is fixedly connected to the first connecting groove 610, and the chassis connecting seat 400 has an air hole 630 that communicates with the first connecting groove 610, allowing the reinforcing airbag 600 to be inflated or deflated through the air hole 630. In this embodiment, the air hole 630 is directly located on the wall of the chassis connecting seat 400, so it does not affect the tight fit between the chassis connecting seat 400 and the cylinder 210. Furthermore, the short distance between the air hole 630 and the reinforcing airbag 600 improves inflation and deflation efficiency and facilitates operation. The reinforcing airbag 600 is fixedly connected in the first connecting groove 610. When the reinforcing airbag 600 is deflated, the deflated reinforcing airbag 600 will retract into the first connecting groove 610 and move with the chassis connecting seat 400. When it moves to the required position, the second connecting groove 620 located on the cylinder 210 at that position corresponds to the first connecting groove 610. Then, the reinforcing airbag 600 is inflated through the air hole 630, so that the inflated reinforcing airbag 600 is jointly accommodated by the first connecting groove 610 and the second connecting groove 620. The reinforcing airbag 600 is subjected to shear force to prevent relative axial movement between the chassis connecting seat 400 and the cylinder 210.

[0037] Furthermore, in a preferred embodiment of this application, an air passage 640 is provided within the chassis connecting seat 400, and a main opening 650 is provided on the outer wall of the chassis connecting seat 400, which communicates with each air hole 630. The main opening 650 communicates with the air passage 640 to simultaneously inflate and deflate each reinforced airbag 600. The air passage 640 is embedded within the chassis connecting seat 400 body, with one side of the air hole connected to the air passage 640 and the other side connected to the first connecting groove 610. The main opening 650 is located on the outer wall of the chassis connecting seat 400 and communicates with the air passage 640. Except for communicating with the main opening 650 and the air hole, the remaining portion of the air passage 640 is enclosed within the chassis connecting seat 400 body. When inflation or deflation is required, the operation is performed through the main opening 650, simultaneously inflating and deflating all air holes connected to the same air passage 640, achieving synchronous inflation and deflation of multiple reinforced airbags 600, saving time and effort.

[0038] Furthermore, in this embodiment, the sliding cavity 410 preferably has a sliding groove on its wall surface, and the cylinder body 210 has a sliding rib on its outer wall. Both the sliding groove and the sliding rib extend axially along the cylinder body 210, and the sliding rib is slidably connected to the sliding groove. This provides guidance for adjusting the position of the chassis connecting seat 400 axially, making it easier for the operator to adjust the position of the chassis connecting seat 400. On the other hand, it also prevents the chassis connecting seat 400 from rotating circumferentially relative to the cylinder body 210, thereby improving the circumferential stability of the chassis connecting seat 400.

[0039] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A height-adjustable shock absorber comprising a shock absorbing spring, a damper, a body connecting seat and a chassis connecting seat, the damper comprising a cylinder and a piston body, the body connecting seat being fixed to the upper end of the piston body, the chassis connecting seat being provided at the lower end of the cylinder, characterized in that, The chassis connecting seat is in a ring structure and forms a sliding cavity, the chassis connecting seat is sleeved on the cylinder through the sliding cavity, at least one fastening assembly is arranged on the chassis connecting seat in the circumferential direction, the fastening assembly comprises a fixing sleeve, a reset spring and a fastening bolt slidingly arranged in the fixing sleeve, both ends of the fixing sleeve are throughly arranged, both ends of the fastening bolt respectively extend out of both ends of the fixing sleeve, the chassis connecting seat is provided with a through hole corresponding to the fixing sleeve, the outer wall of the cylinder is provided with a positioning hole, the reset spring is in contact with the fixing sleeve and the fastening bolt respectively, so as to drive the fastening bolt to pass through the through hole and cooperate with the positioning hole.

2. A height adjustable shock absorber according to claim 1, wherein, The fastening bolt is arranged vertically to the axial direction of the cylinder, or the fastening bolt is arranged obliquely from the end away from the cylinder to the end close to the cylinder.

3. A height adjustable shock absorber according to claim 1, wherein, The end of the fastening bolt away from the cylinder extends out of the fixing sleeve, and a puller is fixed thereon, the diameter of the puller is greater than the diameter of the fastening bolt.

4. A height adjustable shock absorber according to claim 3, wherein, At least one row of the fastening assemblies arranged along the axial direction of the cylinder is arranged on the chassis connecting seat, and the pullers in the same row are fixedly connected with a linkage rod, so as to simultaneously drive the fastening bolts in the same row to move through the linkage rod.

5. A height adjustable shock absorber according to claim 1, wherein, A plurality of reinforcing air bags are arranged between the cylinder and the chassis connecting seat, the reinforcing air bags are respectively matched with the cylinder and the chassis connecting seat, so that the chassis connecting seat and the cylinder are relatively fixed.

6. A height adjustable shock absorber according to claim 5, wherein, A first connecting groove is arranged on the wall surface of the sliding cavity, a second connecting groove is arranged on the outer wall of the cylinder, the reinforcing air bags are fixedly connected with the first connecting groove, and a gas hole is arranged on the chassis connecting seat, the gas hole communicates with the first connecting groove, so that the reinforcing air bags are inflated and deflated through the gas hole.

7. A height adjustable shock absorber according to claim 6, wherein, An air channel is arranged in the chassis connecting seat, a total port is arranged on the outer wall of the chassis connecting seat, the air channel communicates with each gas hole, and the total port communicates with the air channel, so that each reinforcing air bag is inflated and deflated at the same time.

8. A height adjustable shock absorber according to claim 1, wherein, A sliding groove is arranged on the wall surface of the sliding cavity, and a sliding rib is arranged on the outer wall of the cylinder, the sliding groove and the sliding rib both extend along the axial direction of the cylinder, and the sliding rib and the sliding groove are in sliding cooperation.

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