Double-floating expanding pin

Abstract

The utility model provides a double-floating expanding pin, which relates to the technical field of automobile related accessories and comprises a cylinder body structure and an upper cover structure which are connected with each other. The upper cover structure comprises a connecting assembly and two pull rod fixing assemblies, one ends of the two pull rod fixing assemblies are used for being connected with through holes of external machined parts in an inserted mode, and the other ends of the two pull rod fixing assemblies are connected with the connecting assembly. The cylinder body structure comprises a piston, and the piston is connected with the connecting assembly and used for driving the two pull rod fixing assemblies to ascend and descend through the connecting assembly. The technical problems that in the prior art, two pull rods cannot be synchronously pushed and pulled through one piston, the dustproof effect is poor, and the applicability is poor due to the requirement for the hole pitch of a workpiece are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile related accessories, in particular to a double floating diameter expanding pin. Background Art

[0002] Parts with a through hole in the center are mostly clamped from the through hole of a cylindrical part. Existing fixtures mostly use a positioning base and a pressure plate to fix the parts. A positioning column is provided on the positioning base. The diameter of the positioning column is slightly smaller than the diameter of the through hole. The through hole of the part is inserted into the positioning column to achieve connection, and the existing expansion pin cannot push two pull rods through a piston.

[0003] However, the existing expansion pin has a relatively simple structure, and uses spring force to push the piston to drive the cone sleeve to expand and clamp the workpiece, and uses oil pressure to push the piston upward when releasing. In this process, there is no compensation action, that is, it can only move straight up and down. This method has high requirements for the hole distance of the workpiece. If the hole distance of the workpiece deviates, the insertion connection cannot be achieved. In addition, there is no dustproof design at the top of the pull rod of the existing expansion pin, which makes it easy for small chips and liquids to enter the interior of the product, which may damage the workpiece in serious cases. Utility Model Content

[0004] The utility model aims to provide a double floating expanding pin to alleviate the technical problems existing in the prior art, such as the inability to synchronously push and pull two pull rods by one piston, poor dustproof effect, and poor applicability due to the requirements on the workpiece hole distance.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] In a first aspect, the utility model provides a double floating enlarged diameter pin, comprising a cylinder structure and an upper cover structure, wherein the cylinder structure is connected to the upper cover structure;

[0007] The upper cover structure includes a connecting assembly and two groups of tie rod fixing assemblies, one end of the two groups of tie rod fixing assemblies are respectively used to be plugged into the through holes of the external processing parts, and the other ends are connected to the connecting assembly;

[0008] The cylinder structure includes a piston, which is connected to the connecting assembly, and the piston is used to drive the two groups of the pull rod fixing assemblies to rise and fall through the connecting assembly.

[0009] Furthermore, the upper cover structure further comprises an upper cover body, and the upper cover body is connected to the cylinder structure;

[0010] The upper cover body is provided with a receiving cavity, and the receiving cavity receives the connecting assembly and two groups of the pull rod fixing assemblies;

[0011] One end of the two groups of pull rod fixing components is arranged in the accommodating cavity, and the other end is used to pass through the upper cover body and be plugged into the through hole of the processing piece.

[0012] Furthermore, the tie rod fixing assembly comprises a tie rod, a cone body and a cone sleeve, and the cone sleeve is connected to one end of the tie rod passing through the upper cover body;

[0013] The vertebral body is slidably connected to the rod wall of the pull rod, and one end of the vertebral body is connected to the connecting assembly, and the other end is used to be inserted between the cone sleeve and the pull rod so that the cone sleeve expands toward the surroundings and is tightly connected to the through hole wall of the workpiece.

[0014] Furthermore, the pull rod fixing assembly further comprises a special-shaped nut, the special-shaped nut is connected to an end of the pull rod away from the cone sleeve, and the special-shaped nut is connected to the connecting assembly;

[0015] The connecting assembly is used to drive the pull rod to move downward through the special-shaped nut, thereby driving the vertebral body to withdraw from the cone sleeve.

[0016] Further, the connecting assembly includes a disc spring, a locking nut, a connecting block and a short pin, the connecting block is connected to the piston through the short pin, and the connecting block is connected to the special-shaped nut;

[0017] The locking nut is connected to the pull rod, one end of the locking nut is connected to the connecting block, and the other end is connected to the vertebral body through the disc spring.

[0018] Furthermore, the upper cover structure also includes a dust ring, which is connected to the inner wall of the accommodating cavity and the outer wall of the pull rod fixing assembly to seal the gap between the pull rod fixing assembly and the inner wall of the accommodating cavity.

[0019] Furthermore, the cylinder structure also includes a cylinder body, the cylinder body is connected to the upper cover body, and the cylinder body is connected to the piston.

[0020] Furthermore, a first sealing ring is provided on the top of the cylinder body, and the first sealing ring is used to seal the gap between the cylinder body and the upper cover body;

[0021] A second sealing ring is provided at the bottom of the cylinder body.

[0022] Furthermore, the piston is provided with a U-shaped ring, a third sealing ring and a fourth sealing ring from top to bottom, and the U-shaped ring, the third sealing ring and the fourth sealing ring are all in close contact with the cylinder body to seal the gap between the piston and the cylinder body.

[0023] Furthermore, the cylinder structure also includes a screw, which is connected to the bottom of the cylinder body and is used to connect to an external structure.

[0024] The utility model can achieve the following beneficial effects:

[0025] In the first aspect, the utility model provides a double floating expanding pin, including a cylinder structure and an upper cover structure, wherein the cylinder structure is connected to the upper cover structure; the upper cover structure includes a connecting assembly and two sets of tie rod fixing assemblies, one end of the two sets of tie rod fixing assemblies are respectively used to be plugged into the through holes of an external workpiece, and the other ends are connected to the connecting assembly; the cylinder structure includes a piston, the piston is connected to the connecting assembly, and the piston is used to drive the two sets of tie rod fixing assemblies to rise and fall through the connecting assembly.

[0026] In the utility model, the cylinder structure is connected to the upper cover structure, and a connecting assembly and two groups of pull rod fixing assemblies are provided in the upper cover structure, and the connecting assembly is respectively connected to the two groups of pull rod fixing assemblies; and a piston is provided in the cylinder structure. When in use, the connecting assembly is pushed upward by the piston, driving the two groups of pull rod fixing assemblies to move up or down synchronously, thereby realizing the effect of synchronously pushing and pulling the two pull rods by only one piston.

[0027] Compared with the prior art, the double floating expanding pin provided by the utility model synchronously drives two groups of tie rod fixing assemblies to move through the connecting assembly via the piston accommodated in the cylinder structure, thereby realizing the connection by inserting the tie rod fixing assembly into the through hole of the workpiece.

[0028] In summary, the utility model at least alleviates the technical problems existing in the prior art, such as the inability to synchronously push and pull two pull rods by one piston, poor dust prevention effect, and poor applicability due to the requirements on the hole distance of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the three-dimensional structure of the double floating enlarging pin provided by the embodiment of the utility model in the use state;

[0031] Figure 2 A schematic diagram of the main structure of the double floating enlarging pin provided in an embodiment of the utility model in a use state;

[0032] Figure 3A schematic diagram of the top view of the double floating enlarging pin in use provided by an embodiment of the utility model;

[0033] Figure 4 for Figure 3 AA cross-sectional structure diagram in;

[0034] Figure 5 A schematic top view of the structure of a double floating expanding pin provided in an embodiment of the utility model.

[0035] Icons: 1-cylinder structure; 11-cylinder body; 111-first sealing ring; 112-second sealing ring; 12-piston; 121-U-ring; 122-third sealing ring; 123-fourth sealing ring; 13-screw; 2-upper cover structure; 21-upper cover body; 22-pull rod fixing assembly; 221-pull rod; 222-vertebral body; 223-taper sleeve; 224-special-shaped nut; 23-connecting assembly; 231-disc spring; 232-locking nut; 233-connecting block; 234-short pin; 24-dustproof ring; 25-gas inspection channel; 3-processed parts. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0039] In the description of the present utility model, it should be noted that the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the utility model product is usually placed when in use, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0040] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0041] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting", "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0043] Embodiment 1

[0044] This embodiment provides a double floating enlarged diameter pin, referring to Figure 1 , Figure 2 or Figure 3 The double floating expanding pin includes a cylinder structure 1 and an upper cover structure 2, wherein the cylinder structure 1 is connected to the upper cover structure 2; the upper cover structure 2 includes a connecting assembly 23 and two groups of tie rod fixing assemblies 22, wherein one end of the two groups of tie rod fixing assemblies 22 are respectively used to be plugged into the through holes of the external workpiece 3, and the other ends are connected to the connecting assembly 23; the cylinder structure 1 includes a piston 12, which is connected to the connecting assembly 23, and the piston 12 is used to drive the two groups of tie rod fixing assemblies 22 to rise and fall through the connecting assembly 23.

[0045] The embodiments of the utility model at least alleviate the technical problems existing in the prior art, that is, the two pull rods 221 cannot be pushed and pulled synchronously by one piston 12, the dustproof effect is poor, and the applicability is poor due to the requirements on the hole distance of the workpiece.

[0046] In an embodiment of the utility model, the cylinder structure 1 is connected to the upper cover structure 2, and a connecting component 23 and two groups of tie rod fixing components 22 are provided in the upper cover structure 2, and the connecting component 23 is respectively connected to the two groups of tie rod fixing components 22; and a piston 12 is provided in the cylinder structure 1. When in use, the connecting component 23 is pushed upward by the piston 12, driving the two groups of tie rod fixing components 22 to move up or down synchronously, thereby realizing the effect of synchronously pushing and pulling the two tie rods 221 by only one piston 12.

[0047] Compared with the prior art, the double floating expanding pin provided in the embodiment of the utility model synchronously drives the two sets of tie rod fixing assemblies 22 to move through the connecting assembly 23 via the piston 12 accommodated in the cylinder structure 1, thereby realizing the insertion of the tie rod fixing assembly 22 into the through hole of the workpiece 3 for connection.

[0048] In an optional implementation manner of this embodiment, refer to Figure 4 The upper cover structure 2 also includes an upper cover body 21, which is connected to the cylinder structure 1; the upper cover body 21 is provided with a receiving cavity, which receives a connecting component 23 and two groups of tie rod fixing components 22; one end of the two groups of tie rod fixing components 22 is arranged in the receiving cavity, and the other end is used to pass through the upper cover body 21 and be plugged into the through hole of the processing part 3.

[0049] Specifically: the upper cover body 21 is provided with a accommodating cavity, and a connecting component 23 is provided at the bottom of the accommodating cavity, and a single space for accommodating two groups of tie rod fixing components 22 is provided above the accommodating cavity, and the other ends of the two groups of tie rod fixing components 22 pass through the upper cover body 21 and are plugged into the through holes of the processed part 3.

[0050] Further, refer to Figure 4 The pull rod fixing assembly 22 includes a pull rod 221, a vertebral body 222 and a conical sleeve 223. The conical sleeve 223 is connected to one end of the pull rod 221 that passes through the upper cover body 21; the vertebral body 222 is slidably connected to the rod wall of the pull rod 221, and one end of the vertebral body 222 is connected to the connecting assembly 23, and the other end is used to be inserted between the conical sleeve 223 and the pull rod 221 so that the conical sleeve 223 expands to the surroundings, and then is tightly connected to the through hole wall of the workpiece 3.

[0051] Specifically, one end of the pull rod 221 is inserted into the connecting assembly 23, and the other end is used to pass through the upper cover body 21 and plug into the through hole of the workpiece 3, and the cone body 222 is slidably sleeved on the pull rod 221 along the circumferential direction of the pull rod 221, and the cone sleeve 223 is sleeved on one end of the pull rod 221 located outside the upper cover body 21, and the bottom of the cone sleeve 223 is in an open state. During use, the pull rod 221 and the cone sleeve 223 are first inserted into the through hole of the workpiece 3, and then the cone body 222 is pushed up so that the cone body 222 is inserted into the cone sleeve 223, so as to support the cone sleeve 223 and tightly abut the through hole, thereby fixing the workpiece 3.

[0052] Further, refer to Figure 4 The pull rod fixing assembly 22 also includes a special-shaped nut 224, which is connected to one end of the pull rod 221 away from the tapered sleeve 223, and the special-shaped nut 224 is connected to the connecting assembly 23; the connecting assembly 23 is used to drive the pull rod 221 to move downward through the special-shaped nut 224, and then drive the vertebral body 222 to withdraw from the tapered sleeve 223.

[0053] Specifically: the special-shaped nut 224 is connected to one end of the pull rod 221 away from the tapered sleeve 223, and the special-shaped nut 224 is connected to the connecting assembly 23; preferably, when the pull rod 221 needs to be separated from the workpiece 3, the pull rod fixing assembly 22 and the vertebral body 222 are driven downward by pulling down the connecting assembly 23, at which time the vertebral body 222 is disengaged from the tapered sleeve 223, thereby loosening the connection tightness between the pull rod 221 and the workpiece 3.

[0054] Further, refer to Figure 4 The connecting assembly 23 includes a disc spring 231, a locking nut 232, a connecting block 233 and a short pin 234. The connecting block 233 is connected to the piston 12 through the short pin 234, and the connecting block 233 is connected to the special-shaped nut; the locking nut 232 is connected to the pull rod 221, and one end of the locking nut 232 is connected to the connecting block 233, and the other end is connected to the vertebral body 222 through the disc spring 231.

[0055] Specifically: a short pin 234 is provided at the center of the connecting block 233, and the connecting block 233 is connected to the piston 12 through the short pin 234, that is, the short pin 234 is driven by the piston 12 to help the connecting block 233 rise or fall, and two groups of disc springs 231 and locking nuts 232 are provided on the top of the connecting block 233, and each group of disc springs 231 and locking nuts 232 are connected to the corresponding pull rod fixing assembly 22, that is, the locking nut 232 is connected to the pull rod 221, and the disc spring 231 is provided at the top of the locking nut 232 and abuts against the vertebral body 222.

[0056] In an optional implementation manner of this embodiment, refer to Figure 4The upper cover structure 2 also includes a dust ring 24, which is connected to the inner wall of the accommodating cavity and the outer wall of the pull rod fixing assembly 22, so as to seal the gap between the pull rod fixing assembly 22 and the inner wall of the accommodating cavity.

[0057] Specifically: the dust ring 24 is connected to the inner wall of the accommodating cavity, and the dust ring 24 is connected to the outer wall of the pull rod fixing assembly 22, and preferably, the dust ring 24 is located near the top of the accommodating cavity to perform dust-proof sealing on the interior from a higher position.

[0058] In an optional implementation manner of this embodiment, refer to Figure 4 The cylinder structure 1 further includes a cylinder body 11 , which is connected to the upper cover body 21 , and the cylinder body 11 is connected to the piston 12 .

[0059] Specifically: the cylinder body 11 is connected to the upper cover body 21 , and the cylinder body 11 is connected to the piston 12 ; preferably, the cylinder body 11 is provided with a chamber for accommodating the piston 12 , and the piston 12 is located at the inner center of the cylinder body 11 .

[0060] Further, refer to Figure 4 A first sealing ring 111 is provided at the top of the cylinder body 11 , and the first sealing ring 111 is used to seal the gap between the cylinder body 11 and the upper cover body 21 ; a second sealing ring 112 is provided at the bottom of the cylinder body 11 .

[0061] Specifically: a first sealing ring 111 is provided on the top of the cylinder body 11, and a second sealing ring 112 is provided on the bottom thereof; preferably, the first sealing ring 111 is used for sealing with the upper cover body 21, and the second sealing ring 112 is used for sealing when connected with an external structure.

[0062] In an optional implementation manner of this embodiment, refer to Figure 4 The piston 12 is provided with a U-shaped ring 121, a third sealing ring 122 and a fourth sealing ring 123 from top to bottom. The U-shaped ring 121, the third sealing ring 122 and the fourth sealing ring 123 are all in close contact with the cylinder body 11 to seal the gap between the piston 12 and the cylinder body 11.

[0063] Specifically: the U-shaped ring 121, the third sealing ring 122 and the fourth sealing ring 123 are arranged in sequence along the extension direction of the piston 12 to achieve close contact with the cylinder body 11; and preferably, the upper half of the piston 12 is in close contact with the cylinder body 11 through the U-shaped ring 121; the lower half of the piston 12 is in close contact with the cylinder body 11 through the third sealing ring 122, and an oil path entry structure is provided at the bottom of the piston 12, and the fourth sealing ring 123 is used to closely contact the joint between the oil path entry structure and the cylinder body 11.

[0064] In an optional implementation manner of this embodiment, refer to Figure 2 or Figure 4 The cylinder structure 1 further includes a screw 13, which is connected to the bottom of the cylinder body 11 and is used to connect to an external structure.

[0065] Specifically: the screw 13 is connected to the bottom of the cylinder body 11, and there are multiple screws 13, and the multiple screws 13 are used to connect with the external structure; and the second sealing ring 112 is arranged on the outside of the screw 13, for surrounding the screw 13 and sealing the connection between the outside of the screw 13 and the external structure.

[0066] Further, refer to Figure 5 An air inspection channel 25 is provided in the upper cover body 21 , and the air inspection channel 25 is used to perform air inspection on the upper cover body 21 through an external air supply device.

[0067] Preferably, there is a gap between the outer walls of the connecting block 233, the locking nut 232 and the vertebral body 222 and the inner wall of the accommodating cavity of the upper cover body 21, so that the pull rod 221 connected to the connecting block 233, the locking nut 232 and the vertebral body 222 can be moved slightly relative to the upper cover body 21; therefore, the spacing between the two pull rods 221 can be adjusted over a short distance, so that the expansion pin has better applicability to the two through holes with different spacings in the workpiece 3, that is, the workpieces 3 of more specifications can be positioned and fixed by the pull rod 221 structure with adjustable spacing.

[0068] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other; the above embodiments in this specification are only used to illustrate the technical solution of the utility model, rather than to limit it; although the utility model is described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that: it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to replace some or all of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A double floating expansion pin, characterized in that: It comprises a cylinder structure (1) and an upper cover structure (2), wherein the cylinder structure (1) is connected to the upper cover structure (2); The upper cover structure (2) comprises a connecting assembly (23) and two groups of tie rod fixing assemblies (22), one end of the two groups of tie rod fixing assemblies (22) are respectively used to be plugged into the through holes of the external processing part (3), and the other ends are connected to the connecting assembly (23); The cylinder structure (1) comprises a piston (12), the piston (12) is connected to the connecting assembly (23), and the piston (12) is used to drive the two groups of the pull rod fixing assemblies (22) to rise and fall through the connecting assembly (23).

2. The double floating expanding pin according to claim 1, characterized in that: The upper cover structure (2) further comprises an upper cover body (21), and the upper cover body (21) is connected to the cylinder structure (1); The upper cover body (21) is provided with a receiving cavity, and the receiving cavity receives the connecting assembly (23) and two groups of the pull rod fixing assemblies (22); One end of the two groups of pull rod fixing components (22) is arranged in the accommodating cavity, and the other end is used to pass through the upper cover body (21) and be plugged into the through hole of the processing piece (3).

3. The double floating expanding pin according to claim 2, characterized in that: The pull rod fixing assembly (22) comprises a pull rod (221), a cone (222) and a cone sleeve (223), wherein the cone sleeve (223) is connected to one end of the pull rod (221) passing through the upper cover body (21); The vertebral body (222) is slidably connected to the rod wall of the pull rod (221), and one end of the vertebral body (222) is connected to the connecting assembly (23), and the other end is used to be inserted between the cone sleeve (223) and the pull rod (221) so that the cone sleeve (223) expands toward the surroundings and is tightly connected to the through hole wall of the processing part (3).

4. The double floating expanding pin according to claim 3, characterized in that: The pull rod fixing assembly (22) further comprises a special-shaped nut (224), wherein the special-shaped nut (224) is connected to an end of the pull rod (221) away from the cone sleeve (223), and the special-shaped nut (224) is connected to the connecting assembly (23); The connecting assembly (23) is used to drive the pull rod (221) to move downward through the special-shaped nut (224), thereby driving the vertebral body (222) to withdraw from the cone sleeve (223).

5. The double floating expanding pin according to claim 4, characterized in that: The connecting assembly (23) comprises a disc spring (231), a locking nut (232), a connecting block (233) and a short pin (234); the connecting block (233) is connected to the piston (12) via the short pin (234), and the connecting block (233) is connected to the special-shaped nut; The locking nut (232) is connected to the pull rod (221), and one end of the locking nut (232) is connected to the connecting block (233), and the other end is connected to the vertebral body (222) through the disc spring (231).

6. The double floating expanding pin according to claim 2, characterized in that: The upper cover structure (2) also includes a dust ring (24), which is connected to the inner wall of the accommodating cavity, and the dust ring (24) is connected to the outer wall of the pull rod fixing assembly (22) to seal the gap between the pull rod fixing assembly (22) and the inner wall of the accommodating cavity.

7. The double floating expanding pin according to claim 2, characterized in that: The cylinder structure (1) further comprises a cylinder body (11), wherein the cylinder body (11) is connected to the upper cover body (21), and the cylinder body (11) is connected to the piston (12).

8. The double floating expanding pin according to claim 7, characterized in that: A first sealing ring (111) is provided on the top of the cylinder body (11), and the first sealing ring (111) is used to seal the gap between the cylinder body (11) and the upper cover body (21); A second sealing ring (112) is provided at the bottom of the cylinder body (11).

9. The double floating expanding pin according to claim 7, characterized in that: The piston (12) is provided with a U-shaped ring (121), a third sealing ring (122) and a fourth sealing ring (123) at intervals from top to bottom. The U-shaped ring (121), the third sealing ring (122) and the fourth sealing ring (123) are all in close contact with the cylinder body (11) to achieve sealing of the gap between the piston (12) and the cylinder body (11).

10. The double floating expanding pin according to any one of claims 7 to 9, characterized in that: The cylinder structure (1) further comprises a screw (13), wherein the screw (13) is connected to the bottom of the cylinder body (11), and the screw (13) is used to connect to an external structure.

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