Sealing piston structure and backdoor hydraulic damping limitless limiter applying same

Abstract

The invention relates to a sealing piston structure and a backdoor hydraulic damping limitless limiter applying the same, the sealing piston structure comprises a shaft rod and a piston assembly, the piston assembly comprises a valve element, a first guide sleeve and a second guide sleeve, the first guide sleeve and the second guide sleeve are arranged on the two sides of the valve element, a first sliding block is arranged on the first guide sleeve, and a second sliding block is arranged on the second guide sleeve. A first spring is arranged on one side of the first sliding block, a second sliding block is arranged on the second guide sleeve, and a second spring is arranged on one side of the second sliding block. A first sealing ring is arranged on the outer side of the valve element and clamped between the first guide sleeve and the second guide sleeve. The valve core is fixed on the shaft rod; the device has the functions of limiting buffering and mute buffering, no insensitive force exists in the door opening or closing process, and the applied force is constant.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of endless limiters, and particularly relates to a sealed piston structure and a back door hydraulic damping endless limiter applying the same. BACKGROUND

[0002] In existing automobile tail door stoppers, mechanical limiters can only stay at fixed angles and have poor flexibility; ordinary spring openers have uneven opening and closing speeds and are prone to impact; and air spring openers are greatly affected by temperature and have unstable damping force. These defects result in low convenience, large noise and easy wear of components of the tail door, and the tail door cannot meet the needs of users for flexible opening, stable and silent operation.

[0003] An existing patent application with the publication number CN117738553A discloses a noise-reducing endless limiter, the valve core structure of which is complex, the assembly precision requirement is high, and the assembly and production are inconvenient. The present application is improved on this basis. SUMMARY

[0004] This section aims to summarize some aspects of the embodiments of the application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the application.

[0005] In view of the following technical problems in the prior art: solving the technical problems that the existing tail door stopper cannot realize stable stay at any angle, the opening and closing process is unstable, and it is greatly affected by environmental temperature.

[0006] To solve the above technical problems, the application provides the following technical solutions: a sealed piston structure, comprising,

[0007] The shaft rod and the piston assembly, the piston assembly comprising a valve core, first and second guide sleeves arranged on both sides of the valve core, a first sliding block arranged on the first guide sleeve, a first spring arranged on one side of the first sliding block, a second sliding block arranged on the second guide sleeve, and a second spring arranged on one side of the second sliding block;

[0008] A first sealing ring is arranged on the outer side of the valve core and clamped between the first and second guide sleeves.

[0009] The valve core is fixed on the shaft rod.

[0010] As a preferred technical solution of the sealed piston structure, the first sliding block comprises an inner sleeve, a circular plate arranged on the outer side of the sleeve, and an outer sleeve arranged on one side of the circular plate, the circular plate is provided with a first circular hole, the outer sleeve is provided with a second circular hole, and the second circular hole is communicated with the first circular hole.

[0011] As a preferred technical scheme of the sealing piston structure, a plurality of first bevels are arranged at one side edge of the valve core, and a plurality of second bevels are arranged at the other side edge of the valve core.

[0012] As a preferred technical scheme of the sealing piston structure, a gasket is arranged on the shaft rod, the gasket is in contact with one side of the second guide sleeve through a locking nut, and the second spring is connected with the second sliding block and the gasket.

[0013] As a preferred technical scheme of the sealing piston structure, side grooves are arranged on both sides of the valve core, and first damping washers are arranged in the side grooves.

[0014] The application further discloses a back door hydraulic damping infinite limit stopper using the sealing piston structure, and the back door hydraulic damping infinite limit stopper further comprises,

[0015] An outer pipe is sleeved at one end of an inner pipe, a cylinder barrel is arranged in the inner pipe, a piston rod is arranged in the outer pipe, and the cylinder barrel is provided with an isolation piston, so that the cylinder barrel is divided into an oil cavity and an air cavity.

[0016] The shaft rod is arranged at the end of the piston rod, and the piston rod and the shaft rod are arranged in the oil cavity.

[0017] As a preferred technical scheme of the back door hydraulic damping infinite limit stopper, a buffer piece is arranged on the piston rod, the buffer piece comprises a buffer framework shell, the buffer framework shell is sleeved on the piston rod, the buffer framework shell is fixedly connected with the cylinder barrel, and an open groove is arranged at the other end of the buffer framework shell.

[0018] A second damping washer is arranged on the inner side of the buffer framework shell.

[0019] As a preferred technical scheme of the back door hydraulic damping infinite limit stopper, a fixed seat and a buffer piston are arranged in the open groove, one end of the fixed seat is provided with a side hook, the side hook is arranged on the side surface of the end of the piston rod, a first spring is connected with the fixed seat and a first sliding block, and a buffer damping washer is arranged between the buffer piston and the fixed seat.

[0020] As a preferred technical scheme of the back door hydraulic damping infinite limit stopper, a buffer washer is arranged on one side of the buffer piston, a PTFE ring is arranged between the buffer washer and the buffer piston, an open retainer ring is arranged on the inner side of the buffer washer, and a damping hole is arranged on the buffer washer.

[0021] As a preferred technical scheme of the back door hydraulic damping infinite limit stopper, the elastic coefficient of the first spring is smaller than the elastic coefficient of the second spring.

[0022] The application has the advantages of limiting and buffering, silent buffering, no dull force in the process of opening and closing the door, and constant force. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0024] Figure 1 The structure diagram of the sealing piston structure in the present application;

[0025] Figure 2 The structure diagram of the first half shell and the second half shell in the present application;

[0026] Figure 3 The overall cross-sectional structure diagram of the non-limiting stopper in the present application;

[0027] Figure 4 The structure diagram of the buffer in the present application;

[0028] Figure 5 The working state structure diagram of the buffer in the present application;

[0029] Figure 6 The three-dimensional cross-sectional structure diagram of the buffer in the present application;

[0030] Figure 7 The working state structure diagram of the piston assembly in the present application;

[0031] Figure 8 The broken line graph of the force required for opening and closing the door in the prior art along with the stroke;

[0032] Figure 9 The broken line graph of the force required for opening and closing the door in the present application along with the stroke.

[0033] 200, piston assembly; 206, second slider; 208, first sealing ring; 202, first guide sleeve; 204a, tube sleeve; 204b, round plate; 204c, outer tube sleeve; 204e, second round hole; 204d, first round hole; 201a, first bevel; 201b, second bevel; 102, locking nut; 203, second guide sleeve; 101, gasket; 201, valve core; 201c, side groove; 201d, first damping gasket; 402, isolation piston; 404, air cavity; 100, shaft; 403, oil cavity; 500, buffer; 401, cylinder; 501, buffer skeleton shell; 501a, second damping gasket; 502, open slot; 503a, side hook; 301, piston rod; 204, first slider; 507, fluorine ring; 506a, open check ring; 506b, damping hole; 205, first spring; 207, second spring; 506, buffer gasket; 506d, first side plate; 504, buffer piston; 504a, second ring plate; 504b, first fence; 504c, second fence; 506c, first ring plate; 504d, first embedding groove; 504e, second embedding groove; 503, fixed seat; 505, damping gasket; 700, locking sleeve; 300, outer tube; 302, bushing; 303, first ball sleeve; 400, inner tube; 405, tail plug; 406, end gasket; 407, second ball sleeve. DETAILED DESCRIPTION

[0034] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the concept of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0036] Secondly, "one embodiment" or "embodiment" referred to herein means that a specific feature, structure or characteristic can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is separate or alternative to other embodiments.

[0037] Thirdly, the present application is described in detail in conjunction with the schematic diagram, and in the detailed description of the embodiments of the present application, the cross-sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application. In addition, three-dimensional spatial dimensions including length, width and depth should be included in actual manufacture.

[0038] Embodiment 1

[0039] With reference to Figures 1-2 The embodiment provides a sealed piston structure, which comprises a shaft 100 and a piston assembly 200, and the piston assembly 200 comprises a valve core 201, a first guide sleeve 202 and a second guide sleeve 203 arranged on the two sides of the valve core 201, a first sliding block 204 arranged on the first guide sleeve 202, a first spring 205 arranged on one side of the first sliding block 204, a second sliding block 206 arranged on the second guide sleeve 203, and a second spring 207 arranged on one side of the second sliding block 206; a first sealing ring 208 is arranged on the outer side of the valve core 201 and is clamped between the first guide sleeve 202 and the second guide sleeve 203; and the valve core 201 is fixed on the shaft 100.

[0040] The first guide sleeve 202 and the second guide sleeve 203, the first sliding block 204 and the second sliding block 206 are symmetrically arranged on the two sides of the valve core 201.

[0041] The first spring 205 and the second spring 207 are connected with components fixed on the shaft 100 in use, so that the first spring 205 and the second spring 207 are in a compressed state, the first sliding block 204 and the second sliding block 206 are extruded and close to the middle, and the first sealing ring 208 is clamped between the first sliding block 204 and the second sliding block 206.

[0042] The first sliding block 204 comprises an inner sleeve 204a, a circular plate 204b arranged on the outer side of the sleeve 204a and an outer sleeve 204c arranged on one side of the circular plate 204b, the circular plate 204b is provided with a first circular hole 204d, the outer sleeve 204c is provided with a second circular hole 204e, and the second circular hole 204e is communicated with the first circular hole 204d.

[0043] The inner sleeve 204a is sleeved on the outer side of the first guide sleeve 202, the outer sleeve 204c is sleeved on the outer side of the valve core 201, the first circular hole 204d is arranged in the axial direction of the sleeve 204a, and the second circular hole 204e is arranged in the radial direction of the sleeve 204a, specifically, the second circular hole 204e is arranged at the connection position of the outer sleeve 204c and the circular plate 204b.

[0044] The second sliding block 206 is the same in structure as the first sliding block 204.

[0045] A plurality of first bevels 201a are arranged at the side lines of one side of the valve core 201, and a plurality of second bevels 201b are arranged at the side lines of the other side of the valve core 201.

[0046] The valve core 201 is in a cylindrical structure, a through hole is arranged in the middle of the valve core 201, the shaft 100 is embedded in the through hole, the first bevel 201a and the second bevel 201b are respectively arranged at the edges of the two side planes of the valve core 201 and are communicated with the outer side of the circumferential surface of the valve core 201 and the side surface.

[0047] The shaft rod 100 is provided with a gasket 101, the gasket 101 is in contact with one side of the second guide sleeve 203 through a locking nut 102; the second spring 207 is connected with the second sliding block 206 and the gasket 101.

[0048] The gasket 101 and the locking nut 102 are arranged at the end of the shaft rod 100, and are used for limiting and positioning the second guide sleeve 203.

[0049] The valve core 201 is provided with a side groove 201c on both sides, and the side groove 201c is provided with a first damping washer 201d.

[0050] The sealing piston structure of the application is arranged in the oil cavity 403 as a whole when applied, and the sealing piston structure is arranged in the oil cavity 403 as a whole when applied. Figure 1 When the shaft rod 100 moves to the right, the hydraulic oil on the right side pushes the first sealing ring 208 and the first sliding block 204 to move to the left, and when the first sealing ring 208 moves to the first bevel 201a, the hydraulic oil flows from the first bevel 201a and flows to the left side of the first sealing ring 208 from the second circular hole 204e and the first circular hole 204d, and the thrust received by the first sealing ring 208 is consistent during the process, so that the operation is smooth and stable.

[0051] Example 2

[0052] Referring to Figures 1-7 The application further discloses a back door hydraulic damping limitless stopper applying the sealing piston structure, and further comprises an outer pipe 300 and an inner pipe 400, the outer pipe 300 is sleeved with one end of the inner pipe 400, the inner pipe 400 is provided with a cylinder barrel 401, the outer pipe 300 is provided with a piston rod 301, the cylinder barrel 401 is provided with an isolation piston 402, the isolation piston 402 divides the cylinder barrel 401 into an oil cavity 403 and a gas cavity 404; the shaft rod 100 is arranged at the end of the piston rod 301, and the piston rod 301 and the shaft rod 100 are arranged in the oil cavity 403.

[0053] The outer pipe 300 is provided with an opening on one side, the inner pipe 400 is embedded in the outer pipe 300 from the opening of the outer pipe, the inner pipe 400 is provided with an opening on one side and communicates with the inside of the outer pipe 300, the end of the cylinder barrel 401 is sleeved with the outside of the piston rod 301, and a sealing mechanism is arranged between the end of the cylinder barrel 401 and the outside of the piston rod 301 for sealing to prevent oil leakage.

[0054] The oil cavity 403 is provided with oil, and the gas cavity 404 is provided with gas.

[0055] The piston assembly 200 is arranged in the oil cavity 403 as a whole, the first sealing ring 208 is arranged between the outside of the valve core 201 and the inner wall of the oil cavity 403, and plays a role in isolating hydraulic oil on both sides.

[0056] The piston rod 301 is provided with a buffer 500, the buffer 500 comprises a buffer skeleton shell 501, the buffer skeleton shell 501 is sleeved on the piston rod 301, the buffer skeleton shell 501 is fixedly connected with the cylinder barrel 401, and the buffer skeleton shell 501 is provided with an open slot 502 at the other end;

[0057] The inner side of the buffer skeleton shell 501 is provided with a second damping washer 501a.

[0058] The diameter of the piston rod 301 is greater than the diameter size of the shaft rod 100.

[0059] The buffer skeleton shell 501 is a shell structure with a circular cross section, is arranged on the outer side of the piston rod 301, is fixed on the piston rod 301 close to the connecting position of the piston rod 301 and the shaft rod 100, is fixed with the cylinder barrel 401, and moves relative to the buffer skeleton shell 501 when the piston rod 301 moves.

[0060] The open slot 502 is provided with a fixing seat 503 and a buffer piston 504, one end of the fixing seat 503 is provided with a side hook 503a, the side hook 503a is arranged on the side surface of the end of the piston rod 301, the first spring 205 is connected between the fixing seat 503 and the first sliding block 204, and the buffer piston 504 and the fixing seat 503 are provided with a damping washer 505.

[0061] The side hook 503a is arranged at the connecting position of the end of the piston rod 301 and the shaft rod 100, and assists in limiting the fixing seat 503.

[0062] The first guide sleeve 202 is in contact with the side hook 503a, and a damping washer is also arranged at the contact position.

[0063] The buffer piston 504 is provided with a buffer washer 506 on one side, the buffer washer 506 and the buffer piston 504 are provided with a fluorine ring 507 therebetween, the inner side of the buffer washer 506 is provided with an open check ring 506a, and the buffer washer 506 is provided with a damping hole 506b.

[0064] The buffer washer 506 comprises a first ring plate 506c and a first side plate 506d arranged on one side of the first ring plate 506c, the buffer piston 504 comprises a second ring plate 504a and a first surrounding plate 504b and a second surrounding plate 504c arranged at both ends of the second ring plate 504a, the first ring plate 506c and the second ring plate 504a are both sleeved on the outer side of the piston rod 301 and are relatively fixed with the piston rod 301, the inner side of the first surrounding plate 504b is provided with a first embedding groove 504d, the inner side of the second surrounding plate 504c is provided with a second embedding groove 504e, the first ring plate 506c is embedded in the second embedding groove 504e, the other end of the fixing seat 503 is embedded in the first embedding groove 504d, and the damping washer 505 is arranged in the first embedding groove 504d.

[0065] The buffer piston 504 and the buffer ring 506 are separately arranged relative to the prior art, facilitating the assembly of the PTFE ring 507.

[0066] The second side plate 504f is arranged outside the second baffle plate 504c, and the PTFE ring 507 is arranged between the second side plate 504f and the first side plate 506d.

[0067] The locking sleeve 700 is arranged at the connection between the outer tube 300 and the inner tube 400, and is used to switch between the relative locking or relative movable state between the outer tube 300 and the inner tube 400. The structure is prior art and will not be described again.

[0068] The outer tube 300 is provided with a bushing 302 at the end, the piston rod 301 is provided with a first ball sleeve 303 at the end, and the inner tube 400 is provided with a tail plug 405, an end gasket 406 and a second ball sleeve 407 at the end.

[0069] In this embodiment, the endless limit stopper is used to connect the tail door and the vehicle body, to improve the hand feeling of opening and closing the tail door, and to open the tail door at a certain angle at any time. Specifically, the second ball sleeve 407 is connected with the connecting structure on the tail door, and the first ball sleeve 303 is connected with the connecting structure on the vehicle body.

[0070] In the prior art, the sealing piston structure is fixed at the end of the piston rod by riveting in a threaded connection manner. This separate structure may cause the sealing piston and the piston rod to move, be prone to gaps, and make abnormal noise and have poor stability after the gap is formed. The piston rod 301 and the shaft rod 100 are integrally formed in this application, and the piston assembly 200 is sleeved on the shaft rod 100 and moves together with the shaft rod 100, so that the tightness is high and the failure rate is low.

[0071] The prior art has a larger weight and a larger device diameter. The original structure has a weight of 1.2 kg, the outer tube has a diameter of Φ27, and after the improvement, the weight is 0.845 g, and the outer tube has a diameter of Φ22, which is more lightweight.

[0072] In the prior art, there is a difference between the locking force and the running force during the movement of the sealing piston. The specific structure is that the oil inlet of the oil-driven sealing structure is relatively small, and a larger force is required to drive the sealing structure to move away, which is the locking force. After the sealing structure is pushed away, the space becomes larger, and the force required for continuous movement becomes smaller, which is the running force. In use, it is reflected that a larger force is required to move the door when pushing the door open or closed, and the force during the movement of the door is smaller than the initial force. Figure 8, Fcl is the compression locking force when closing the door, Fcf is the compression operating force when closing the door, the stroke in the figure represents the relative position of the piston assembly in the oil cavity, when closing the door, the piston assembly moves from the left side to the right side of the oil cavity, and the constant force operates the door closing, and a larger force is required to start the piston assembly at the beginning, and then stop; Fsf is the extension locking force when opening the door, Fsl is the extension operating force when opening the door, and the figure shows that when the door is in an open angle state or a closed state, the piston assembly moves from the right side to the left side of the oil cavity, and a larger force is required to start the door, and then the constant force operates the door opening, and stops at any position.

[0073] It can be seen that the forces required when opening and closing the door in the prior art are different.

[0074] And the resistance (i.e. the force required) when opening or closing the door and during the movement of the door in the present application is maintained constant, and the door is opened smoothly without a dull force; refer to Figure 9 , F3 and F4 are the compression forces when closing the door, and F1 and F2 are the extension forces when opening the door, it can be seen that their sizes are consistent, and there is no distinction between locking force and operating force.

[0075] The elastic coefficient of the first spring 205 is smaller than the elastic coefficient of the second spring 207.

[0076] The elastic coefficients of the first spring 205 and the second spring 207 are set differently, and the elastic coefficient of the second spring 207 near one end of the air cavity is set to be larger, because: the air cavity will have an outward pressure, therefore, first, the side close to the air cavity is more likely to change relative to the oil cavity due to the air cavity pressure, so the right spring is set to be harder, which needs to compensate and overcome the pressure of the air cavity in a stable state; second, in order to make the forces required for opening and closing the door close to each other, the difference in the spring is also for compensation, so that the theoretical force required for opening the door is larger, and the theoretical force required for closing the door is smaller, thereby making the compensation of the forces required for opening and closing the door consistent.

[0077] Further, the cylinder is divided into an oil cavity (working cavity) and a nitrogen cavity (auxiliary cavity) by a separation piston; the nitrogen cavity is the air cavity 404, the oil cavity and the nitrogen cavity are separated by the separation piston 402 in the cylinder, which avoids direct contact between high-pressure nitrogen and hydraulic oil, reduces oxidation of the oil, and prolongs the service life of the device; the high-pressure nitrogen compensates for the volume change in real time, ensures the stability of the oil cavity pressure, and solves the "stuck" problem of traditional hydraulic rods; the hydraulic damping force and the nitrogen thrust work together.

[0078] The specific working state is referred to Figure 7 , Figure 7The left side is a tail gate opening process state diagram, at this time, the outer tube 300 and the inner tube 400 are relatively stretched, the piston rod 301 is relatively moved upward relative to the cylinder 401, and the oil cavity volume is increased; at this time, the high-pressure nitrogen gas of the nitrogen cavity pushes the isolation piston to move leftward, compensates the volume vacancy of the oil cavity, and avoids the negative pressure of the oil cavity; at the same time, the hydraulic oil of the upper side pushes the first sealing ring 208 and the second sliding block 206 to move downward, the hydraulic oil flows downward, and the tail gate opening process is stable by overcoming the resistance of the second spring 207.

[0079] Figure 7 The right side is a tail gate closing process state diagram, at this time, the outer tube and the inner tube are relatively compressed, the piston rod 301 is relatively moved downward relative to the cylinder 401, and the compression oil cavity volume is compressed; the hydraulic oil of the lower side pushes the first sealing ring 208 and the first sliding block 204 to move upward, the hydraulic oil moves upward, generates a reverse damping force, and at the same time, the isolation piston moves downward to compress the nitrogen cavity, the nitrogen pressure is increased, and a reverse thrust is formed to buffer the door closing speed.

[0080] When the tail gate is stopped to be pushed, the spring pushes the sealing ring to reset, the oil liquid stops flowing, the vehicle door is suspended, and the random stop function is realized.

[0081] The present application also has a limiting buffer function, which is embodied in that: the buffer function is realized by the buffer piston 504 and the buffer skeleton shell 501, the outer diameter of the buffer piston 504 is smaller than the outer diameter of the cylinder, so it will not affect the normal movement, when the buffer piston 401 enters the buffer skeleton shell 501, the hydraulic oil in the buffer skeleton shell 501 is compressed, the damping force is generated by the hydraulic oil passing through the damping hole 506b on the piston, and the buffer effect is achieved; the buffer skeleton shell 501 has a buffer washer 506 inside, which reduces the impact sound of the buffer piston 504 and the buffer skeleton shell 501; the buffer piston 504 also has a buffer shock absorber washer 505 inside, which reduces the sound of oil release in the buffer moment.

[0082] The present application also has a mute buffer function, which is embodied in that: the first shock absorber washer 201d on both sides of the valve core 201 absorbs the mechanical impact energy when the second sliding block 206 and the first sliding block 204 reset, and eliminates the "metal impact sound"; the buffer assembly realizes three-stage noise reduction: the damping force buffer impact when the buffer piston 504 enters the buffer skeleton shell 501, the buffer washer 506 in the buffer skeleton shell 501 absorbs the component collision sound, and the buffer shock absorber washer 505 of the buffer piston 504 weakens the "hydraulic sound" of oil release.

[0083] Further, as the temperature decreases, the oil liquid degree increases, and the sliding block can automatically adjust the opening according to the demand, maintains the running resistance during use, and has a low-temperature environment adaptation function.

[0084] It is to be understood that the development of the particular implementations described herein was motivated by the desire to solve real-world problems, and as such the claimed implementations can be susceptible to further implementation while still being generically consistent with the descriptions provided herein. Specifically, although many of the examples provided herein describe one or more implementations with any particular feature, an individual feature can be replaced by alternative features within the scope of the application. Thus, features discussed in one example can be interchanged with features in another example. Any implementation of more than one feature disclosed herein is specifically referenced within the scope of the application.

[0085] It should be noted that the above examples are merely used to illustrate the technical solutions of the present application, rather than limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A sealing piston structure, characterized in that: include, A shaft (100) and a piston assembly (200), wherein the piston assembly (200) comprises a valve core (201), a first guide sleeve (202) and a second guide sleeve (203) arranged on both sides of the valve core (201), wherein the first guide sleeve (202) is provided with a first slider (204), and a first spring (205) is provided on one side of the first slider (204), and the second guide sleeve (203) is provided with a second slider (206), and a second spring (207) is provided on one side of the second slider (206); A first sealing ring (208) is provided on the outside of the valve core (201), and the first sealing ring (208) is clamped between the first guide sleeve (202) and the second guide sleeve (203); The valve core (201) is fixed on the shaft (100).

2. The sealing piston structure according to claim 1, characterized in that: The first sliding block (204) comprises an inner tube sleeve (204a), a circular plate (204b) arranged outside the tube sleeve (204a), and an outer tube sleeve (204c) arranged on one side of the circular plate (204b); a first circular hole (204d) is provided on the circular plate (204b); a second circular hole (204e) is provided on the outer tube sleeve (204c); and the second circular hole (204e) is communicated with the first circular hole (204d).

3. The sealing piston structure according to claim 2, characterized in that: A plurality of first bevels (201a) are provided at one side edge of the valve core (201), and a plurality of second bevels (201b) are provided at the other side edge of the valve core (201).

4. The sealing piston structure according to claim 3, characterized in that: A washer (101) is provided on the shaft (100), and the washer (101) contacts one side of the second guide sleeve (203) through a locking nut (102); the second spring (207) connects the second slider (206) and the washer (101).

5. The sealing piston structure according to claim 4, characterized in that: Side grooves (201c) are provided on both sides of the valve core (201), and a first shock-absorbing washer (201d) is provided in the side grooves (201c).

6. A hydraulic damping unlimited positioner for a back door using the sealing piston structure according to any one of claims 1 to 5, characterized in that: Also includes, An outer tube (300) and an inner tube (400), wherein the outer tube (300) is sleeved on one end of the inner tube (400), a cylinder (401) is provided in the inner tube (400), a piston rod (301) is provided in the outer tube (300), and an isolation piston (402) is provided in the cylinder (401), wherein the isolation piston (402) divides the cylinder (401) into an oil chamber (403) and an air chamber (404); The shaft rod (100) is arranged at the end of the piston rod (301), and the piston rod (301) and the shaft rod (100) are arranged in the oil chamber (403).

7. The tailgate hydraulic damping unlimited positioner according to claim 6, characterized in that: A buffer member (500) is provided on the piston rod (301), and the buffer member (500) includes a buffer skeleton shell (501). The buffer skeleton shell (501) is sleeved on the piston rod (301), the buffer skeleton shell (501) is fixedly connected to the cylinder (401), and an open groove (502) is provided at the other end of the buffer skeleton shell (501); A second shock-absorbing washer (501a) is provided inside the buffer skeleton shell (501).

8. The tailgate hydraulic damping unlimited positioner according to claim 7, characterized in that: A fixing seat (503) and a buffer piston (504) are provided in the opening groove (502); a side hook (503a) is provided at one end of the fixing seat (503); the side hook (503a) is provided on the side of the end of the piston rod (301); a first spring (205) connects the fixing seat (503) and the first slider (204); a shock absorbing washer (505) is provided between the buffer piston (504) and the fixing seat (503).

9. The tailgate hydraulic damping unlimited positioner according to claim 8, characterized in that: A buffer washer (506) is provided on one side of the buffer piston (504), a polytetrafluoroethylene ring (507) is provided between the buffer washer (506) and the buffer piston (504), an open retaining ring (506a) is provided on the inner side of the buffer washer (506), and a damping hole (506b) is provided on the buffer washer (506).

10. The tailgate hydraulic damping unlimited positioner according to any one of claims 7 to 9, characterized in that: The elastic coefficient of the first spring (205) is smaller than the elastic coefficient of the second spring (207).

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