Reducing device

Abstract

The utility model provides a reducing device, which is used for positioning a lug reaming hole of a crane truss arm and comprises a connecting rod, a first driving piece, a second driving piece and a linkage piece, the connecting rod penetrates through the first driving piece and the second driving piece, and the first driving piece and the second driving piece can move on the connecting rod. The linkage piece is connected to the outer wall of the first driving piece and the outer wall of the second driving piece and comprises a linkage part, a first connecting piece and a second connecting piece, the first connecting piece is connected to one end of the linkage part, the second connecting piece is connected to the other end of the linkage part, and the linkage piece has a contraction state and an expansion state; when the connecting rod is rotated to enable the first driving piece and the second driving piece to get close to each other or get away from each other, the linkage piece can be switched between the contraction state and the expansion state, and the linkage part can move relative to the first connecting piece and the second connecting piece. The reducing device can prevent the lug hinge from deforming during welding, and is convenient and fast to disassemble and assemble.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering machinery, in particular to a diameter-changing device for positioning ear-reaming holes of a crane truss arm. Background Art

[0002] The crane boom is made up of multiple truss boom sections, and the boom sections are connected in series by four ear hinges at the front and rear through pins. Therefore, the concentricity and coaxiality between the ear hinges of the truss arm, the flatness and verticality of the four ear hinges on the same side, and the deflection accuracy of the entire truss arm are required to be high. In addition, the ear hinges of the truss arm are machined before welding. When the ear hinges of the truss arm are assembled and welded with the chord rod, due to the large amount of ear hinge welds, large welding deformation will occur after welding. Due to welding deformation and poor positioning, the concentricity and coaxiality of the ear hinge holes of the truss arm will be poor, resulting in interference when the boom sections are installed in series, and rework and repair are often required. In order to ensure the dimensional accuracy of the ear hinges, the current manufacturing method is to use a round steel machine to add a whole pin shaft, and then the pin shaft needs to be passed through the entire ear hinge hole through cooperation with the ear hinge support, and then the welding is completed. However, since the gap between the ear hinge hole diameter and the pin shaft diameter is required to be extremely small, if the gap is too large, the ear hinge force will be offset during welding, resulting in the concentricity and coaxiality between the ear hinges. The extremely small matching gap makes it very difficult to assemble the ear hinges, and workers often need to use a hammer to hammer the pin shaft vigorously to ensure that the pin shaft penetrates the ear hinge support and the ear hinge installation hole; and After welding is completed, due to the existence of welding stress, the pin and the ear hinge are clamped tighter, and a mutual misalignment reaction force occurs between the pin and the ear hinge. Therefore, due to the reaction force, it is more difficult to remove the pin after the workpiece cools to room temperature after welding. Workers need to use a hammer to hammer the pin for a long time to knock the pin out of the ear hinge support and the ear hinge mounting hole. The labor intensity of the workers is high, and since the height of the crane truss arm is relatively high, there is a safety risk when the pin is knocked off. In addition, since the pin is hammered for a long time, it is easy to deform and damage, the pin is replaced frequently, and the production cost is relatively high. Utility Model Content

[0003] In view of this, the purpose of the utility model is to provide a diameter-changing device, which can solve the problems existing in the prior art, avoid deformation of the ear hinge during welding, and is convenient and quick to disassemble and assemble.

[0004] The utility model provides a diameter-changing device, which is used for positioning the ear-reaming hole of a crane truss arm. The device comprises a connecting rod, a first driving member, a second driving member and a linkage member. The first driving member and the second driving member are respectively movably connected to the connecting rod, and the linkage member is connected to the outer wall of the first driving member and the outer wall of the second driving member. The linkage member comprises a linkage part, a first connecting member and a second connecting member. The first connecting member is connected to one end of the linkage part, and the second connecting member is connected to the other end of the linkage part. The linkage member comprises a contracted state and an expanded state. When the connecting rod is rotated to make the first driving member and the second driving member approach each other or move away from each other, the linkage member can switch between the contracted state and the expanded state, and the linkage part can move relative to the first connecting member and the second connecting member.

[0005] In one embodiment, the first driving member is a conical structure, the first driving member includes a first end and a second end, the outer diameter of the first end is smaller than the outer diameter of the second end, the second driving member is a conical structure, the second driving member includes a third end and a fourth end, the outer diameter of the third end is smaller than the outer diameter of the fourth end, the third end is arranged on a side of the second driving member close to the first end; or the fourth end is arranged on a side of the second driving member close to the second end.

[0006] In one embodiment, the linkage portion includes a first reducing end and a second reducing end that are relatively arranged, the first reducing end is provided with a plurality of first waist-shaped holes, a plurality of first fasteners cooperate with the first waist-shaped holes to connect the first reducing end to the first connecting piece, the first fastener can move in the first waist-shaped hole along the length direction of the first waist-shaped hole, a plurality of second fasteners cooperate with the second waist-shaped hole of the second reducing end to connect the second connecting piece, and the second fastener can move in the second waist-shaped hole along the length direction of the second waist-shaped hole.

[0007] In one embodiment, the cross-section of the linkage part is fan-shaped, six linkage parts are provided, and the linkage parts are spliced ​​to form a cylinder.

[0008] In one embodiment, the first driving member is a conical structure, the first driving member includes a first end and a second end, the outer diameter of the first end is smaller than the outer diameter of the second end, the second driving member is a conical structure, the second driving member includes a third end and a fourth end, and the fourth end is arranged on a side of the second driving member close to the second end.

[0009] In one embodiment, the linkage member is provided with a plurality of linkage parts, each of which is circumferentially arranged around the first driving member and the second driving member, each of the linkage parts is respectively provided with a first groove and a second groove, the first driving member is provided with a plurality of first protrusions, each of which is respectively arranged in each of the first grooves, the second driving member is provided with a plurality of second protrusions, each of which is respectively arranged in each of the second grooves, when the first driving member and the second driving member approach each other or move away from each other, the first protrusion can move in the first groove, and the second protrusion can move in the second groove.

[0010] In one embodiment, the linkage portion includes a first sliding surface and a second sliding surface, the first sliding surface and the second sliding surface have opposite inclination directions, the first groove is arranged on the first sliding surface, the first driving member is arranged corresponding to the first sliding surface, the second groove is arranged on the second sliding surface, and the second driving member is arranged corresponding to the second sliding surface.

[0011] In one embodiment, the connecting rod includes a first thread segment and a second thread segment, the first thread segment and the second thread segment have opposite spiral directions, the first driving member is threadedly connected to the first thread segment, and the second driving member is threadedly connected to the second thread segment.

[0012] In one embodiment, both ends of the connecting rod are respectively provided with a clamping groove, and the clamping groove is used to cooperate with a wrench to rotate the connecting rod.

[0013] In one embodiment, the outer diameter expansion range of the diameter-changing device is 0 mm to 5 mm.

[0014] The diameter-changing device of the utility model can realize the contraction and expansion of the outer diameter of the linkage member through the cooperation of the first driving member, the second driving member and the linkage member. When the linkage member is in the contracted state, the outer diameter of the diameter-changing device is smaller than the outer diameter of the ear reaming hole, and the diameter-changing device can be inserted into the ear reaming hole. At this time, the first driving member and the second driving member are moved away from each other by rotating the connecting rod, and the linkage member is in the expanded state. At this time, the outer diameter of the diameter-changing device is the same as the inner diameter of the ear reaming hole, and the diameter-changing device plays a supporting role. When the ear hinge is welded to the chord rod, the diameter of the driving mechanism device is expanded to be consistent with the ear reaming hole. It is installed and tightened with the ear hinge, and welding deformation of the ear hinge can be avoided when it is welded to the chord rod. After welding, wait for the workpiece to cool to room temperature, and then rotate the connecting rod to make the linkage part contracted. At this time, the reducing device can be pulled out from the ear hinge hole, so that the outer diameter of the entire reducing device can be freely retracted and extended. The whole process is convenient, smooth and fast, replacing the original production method of using a fixed pin shaft for positioning, which requires manual repeated use of a hammer to hammer the pin shaft for a long time, ensuring the production quality of the truss arm size, reducing the labor intensity of workers and the cost of using pin shaft materials, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a schematic structural diagram of the diameter-changing device of the first embodiment of the utility model when in use;

[0017] Figure 2 It is a structural schematic diagram of the variable diameter device of the first embodiment of the utility model in an expanded state;

[0018] Figure 3 It is a structural schematic diagram of the diameter-changing device of the first embodiment of the utility model in a contracted state;

[0019] Figure 4 The diameter-changing device of the first embodiment of the utility model is a side view structural schematic diagram;

[0020] Figure 5 It is a structural schematic diagram of the linkage part of the first embodiment of the utility model;

[0021] Figure 6 It is a side structural schematic diagram of the linkage part of the first embodiment of the utility model;

[0022] Figure 7 This is a schematic structural diagram of a first driving member of a first embodiment of the utility model;

[0023] Figure 8 yes Figure 7 A side view structural schematic diagram of;

[0024] Explanation of the accompanying reference numerals: reducing device-10; first groove-101; second groove-102; slot-103; first waist-shaped hole-104; connecting rod-11; first driving member-12; first end-121; second end-122; first protrusion-123; second driving member-13; third end-131; fourth end-132; linkage part-141; first sliding surface-1411; second sliding surface-1412; first reducing end-1413; second reducing end-1414; first connecting member-142; second connecting member-143; first fastener-151; second fastener-152; ear hinge-21; chord rod-22.

[0025] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0026] The following will describe in detail a specific embodiment of the utility model in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Based on the description of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] In the description of the present utility model, unless otherwise clearly specified and limited, the terms "set", "install", "connection" and the like 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 an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0028] The directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of description and simplified description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the utility model.

[0029] The terms "first", "second", "third" and the like are merely used to distinguish elements of similar nature, and do not indicate or imply relative importance or a particular order.

[0030] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of the elements listed and may also include additional elements not expressly listed.

[0031] First embodiment

[0032] like Figures 1 to 8As shown, the diameter-changing device 10 is used to position the ear-reaming hole of the crane truss arm. The diameter-changing device 10 includes a connecting rod 11, a first driving member 12, a second driving member 13 and a linkage member. The first driving member 12 and the second driving member 13 are respectively movably connected to the connecting rod 11. The connecting rod 11 is cylindrical. The linkage member is connected to the outer wall of the first driving member 12 and the outer wall of the second driving member 13. The linkage member includes a linkage part 141, a first connecting member 142 and a second connecting member 143. The first connecting member 142 is connected to one end of the linkage part 141, and the second connecting member 143 is connected to the other end of the linkage part 141. The linkage member includes a contracted state and an expanded state. When the connecting rod 11 is rotated to make the first driving member 12 and the second driving member 13 approach each other or move away from each other, the linkage member can switch between the contracted state and the expanded state, and the linkage part 141 can move relative to the first connecting member 142 and the second connecting member 143. The connecting rod 11 is arranged through the first connecting member 142 and the second connecting member 143. The first connecting member 142 and the second connecting member 143 clamp and fix multiple limiting parts by bolts, which not only prevents the linkage part 141 from scattering and deforming after being stressed, but also ensures that when the first driving member 12 and the second driving member 13 slide, the uniformity and consistency of the outer diameter size of all the linkage parts 141 are retracted, thereby ensuring that the outer diameter of the diameter reducing device 10 and the ear-ream hole of the truss arm ear hinge 21 have a tight gap. The outer diameter of the diameter reducing device 10 has a telescopic range of 0mm to 5mm, wherein, when the diameter reducing device 10 needs to be pulled out, the outer diameter of the diameter reducing device 10 shrinks by 3mm, so that the gap between the inner wall of the ear-ream hole of the outer wall of the diameter reducing device 10 is 3mm, which is convenient for the rapid pulling out of the diameter reducing device 10.

[0033] The variable diameter device 10 of the utility model can realize the contraction and expansion of the outer diameter of the linkage member through the cooperation of the first driving member 12, the second driving member 13 and the linkage member. When the linkage member is in the contracted state, the outer diameter of the variable diameter device 10 is smaller than the outer diameter of the ear reaming hole, and the variable diameter device 10 can be inserted into the ear reaming hole. At this time, the first driving member 12 and the second driving member 13 are moved away from each other by rotating the connecting rod 11, and the linkage member is in the expanded state. At this time, the outer diameter of the variable diameter device 10 is the same as the inner diameter of the ear reaming hole, and the variable diameter device 10 plays a supporting role. When the ear hinge 21 is welded to the chord rod 22, the diameter of the driving mechanism device is expanded to be consistent with the ear reaming hole. The reducing device 10 is installed and tightened with the ear hinge 21. When the ear hinge 21 is welded with the chord rod 22, welding deformation of the ear hinge 21 can be avoided. After welding is completed and the workpiece is cooled to room temperature, the linkage part is retracted by rotating the connecting rod 11. At this time, the reducing device 10 can be pulled out from the ear hinge hole, so that the outer diameter of the entire reducing device 10 can be freely retracted and extended. The whole process is convenient, smooth and fast, replacing the original production method of using a fixed pin shaft for positioning, which requires manual repeated use of a hammer to hammer the pin shaft for a long time, thereby ensuring the production quality of the truss arm size, reducing the labor intensity of workers and the cost of using pin shaft materials, and improving production efficiency.

[0034] like Figure 1 and Figure 5 As shown, the first reducing end 1413 is provided with a plurality of first waist-shaped holes 104, a plurality of first fasteners 151 cooperate with the first waist-shaped holes 104 to connect the first reducing end 1413 with the first connecting member 142, the first fasteners 151 can move in the first waist-shaped hole 104 along the length direction of the first waist-shaped hole 104, a plurality of second fasteners 152 cooperate with the second waist-shaped holes to connect the second reducing end 1414 with the second connecting member 143, and the second fasteners 152 can move in the second waist-shaped hole along the length direction of the second waist-shaped hole.

[0035] like Figure 1 , Figure 7 and Figure 8 As shown, the first driving member 12 is a conical structure, the first driving member 12 includes a first end 121 and a second end 122, the outer diameter of the first end 121 is smaller than the outer diameter of the second end 122, the second driving member 13 is a conical structure, the second driving member 13 includes a third end 131 and a fourth end 132, the outer diameter of the third end 131 is smaller than the outer diameter of the fourth end 132, the third end 131 is arranged on the side of the second driving member 13 close to the first end 121, the first end 121 and the third end 131 are arranged opposite to each other, so when the first driving member 12 and the second driving member 13 approach each other, the linkage member is driven to contract, so that the outer diameter of the linkage member is reduced.

[0036] Preferably, the linkage member is made of a non-elastic material, such as alloy structural steel, so that the linkage member can withstand a larger load and reaction force to meet the use of high-strength material positioning and welding; the linkage member is provided with a plurality of linkage parts 141, each linkage part 141 is circumferentially arranged around the first driving member 12 and the second driving member 13, each linkage part 141 is respectively provided with a first groove 101 and a second groove 102, the first driving member 12 is provided with a plurality of first protrusions 123, each first protrusion 123 is respectively arranged in each first groove 101, the second driving member 13 is provided with a plurality of second protrusions, each second protrusion is respectively arranged in each second In the groove 102, when the first driving member 12 and the second driving member 13 are close to or away from each other, the first protrusion 123 can move in the first groove 101, and the second protrusion can move in the second groove 102. The first protrusion 123 and the second protrusion can prevent the connecting rod 11 from driving the first driving member 12 and the second driving member 13 to move and cause a circular rotation, thereby causing the diameter reducing device 10 to loosen, and avoid the phenomenon that the fixing bolt is worn and broken due to axial shear force; the cross section of the first protrusion 123 is preferably rectangular or fan-shaped, and the cross section of the second protrusion is preferably rectangular or fan-shaped. Among them, the cross section of the linkage part 141 is fan-shaped, and the linkage part 141 is preferably provided with six linkage parts 141, and each linkage part 141 is spliced ​​to form a cylinder. When the diameter reducing device 10 is set in the ear reaming hole, the outer wall of the linkage part 141 contacts the inner wall of the ear reaming hole.

[0037] like Figure 5 As shown, the linkage part 141 includes a first sliding surface 1411 and a second sliding surface 1412. The inclination directions of the first sliding surface 1411 and the second sliding surface 1412 are opposite. The first groove 101 is arranged on the first sliding surface 1411, and the first driving member 12 is arranged corresponding to the first sliding surface 1411. The second groove 102 is arranged on the second sliding surface 1412, and the second driving member 13 is arranged corresponding to the second sliding surface 1412.

[0038] Preferably, the connecting rod 11 includes a first thread segment and a second thread segment, the spiral directions of the first thread segment are opposite to those of the second thread segment, the first driving member 12 is threadedly connected to the first thread segment, and the second driving member 13 is threadedly connected to the second thread segment. When the connecting rod 11 is driven to rotate in a first direction, the first driving member 12 and the second driving member 13 approach each other, and when the connecting rod 11 is driven to rotate in the second direction, the first driving member 12 and the second driving member 13 move away from each other, and the first direction is opposite to the second direction.

[0039] like Figure 1 As shown, both ends of the connecting rod 11 are provided with a clamping groove 103, which is used to cooperate with a wrench to rotate the connecting rod 11. The wrench is preferably an electric wrench. The electric wrench replaces the manual twisting of the connecting rod 11, which reduces the labor intensity.

[0040] Using method of reducing device 10: firstly, use electric torque wrench to automatically rotate connecting rod 11 to drive first driving member 12 and second driving member 13 to slide to two ends of reducing device 10 along first groove 101 and second groove 102 on each linkage part 141 respectively, and the diameter of reducing device 10 shrinks to about 3mm smaller than ear reaming hole, and the shrunk mechanism device has smaller outer diameter, thereby increasing the gap between reducing device 10 and ear reaming hole diameter, so that reducing device 10 can be inserted into ear reaming 21 support and ear reaming hole conveniently, smoothly and quickly, realizing accurate, efficient and fast positioning, after reducing device 10 passes through ear reaming hole, use electric torque wrench to automatically rotate connecting rod 11 to drive first driving member 12 and second driving member 13 to slide to the middle of mechanism device simultaneously along first groove 101 and second groove 102 on each linkage part 141, thereby driving mechanism device diameter to expand to about the same size as ear reaming hole. The mounting holes of the hinge 21 are consistent, the reducing device 10 and the ear hinge 21 are kept installed and tightened, and then the weld of the ear hinge 21 is welded. After the welding is completed, when the workpiece cools to room temperature and the reducing device 10 needs to be removed, the electric torque wrench is used again to automatically twist the connecting rod 11 to drive the first driving member 12 and the second driving member 13 to slide along the first groove 101 and the second groove 102 on each linkage part 141 to the two ends of the reducing device 10 at the same time, and the diameter of the driving mechanism device is shrunk to about 3mm smaller than the mounting hole of the ear hinge 21, and the reducing device 10 is pulled out; the whole process is achieved by automatically twisting the connecting rod 11 to drive the first driving member 12 and the second driving member 13 to slide along the first groove 101 and the second groove 102 on each linkage part 141 at the same time to realize the free-style retraction and extension of the diameter size of the entire reducing device 10. The whole process is convenient, smooth and fast, replacing the original fixed pin positioning that needs to be repeatedly used manually.

[0041] Second embodiment

[0042] The diameter-changing device of this embodiment is substantially the same in structure as the diameter-changing device of the first embodiment, except that the structures of the first driving member and the second driving member are different.

[0043] Specifically, the first driving member 12 is a conical structure, the first driving member 12 includes a first end 121 and a second end 122, the outer diameter of the first end 121 is smaller than the outer diameter of the second end 122, the second driving member 13 is a conical structure, the second driving member 13 includes a third end 131 and a fourth end 132, the fourth end 132 is arranged on the side of the second driving member 13 close to the second end 122, when the connecting rod 11 is rotated to make the first driving member 12 and the second driving member 13 move away from each other, the linkage member is in a contracted state, and when the connecting rod 11 is rotated to make the first driving member 12 and the second driving member 13 move closer to each other, the linkage member is in an expanded state.

[0044] The above are only specific implementations of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model shall be subject to the attached claims.

Claims

1. A diameter reducing device for positioning the ear reaming hole of a crane truss arm, characterized in that: The invention comprises a connecting rod (11), a first driving member (12), a second driving member (13) and a linkage member, wherein the connecting rod (11) passes through the first driving member (12) and the second driving member (13), the first driving member (12) and the second driving member (13) are movable on the connecting rod (11), the linkage member is connected to the outer wall of the first driving member (12) and the outer wall of the second driving member (13), the linkage member comprises a linkage part (141), a first connecting member (142) and a second connecting member (143), The first connecting member (142) is connected to one end of the linkage part (141), and the second connecting member (143) is connected to the other end of the linkage part (141). The linkage part includes a contracted state and an expanded state. When the connecting rod (11) is rotated to make the first driving member (12) and the second driving member (13) approach each other or move away from each other, the linkage part can switch between the contracted state and the expanded state, and the linkage part (141) can move relative to the first connecting member (142) and the second connecting member (143).

2. The diameter-changing device according to claim 1, characterized in that: The linkage part (141) comprises a first reducing end (1413) and a second reducing end (1414) which are arranged opposite to each other. The first reducing end (1413) is provided with a plurality of first waist-shaped holes (104). A plurality of first fasteners (151) cooperate with the first waist-shaped holes (104) to connect the first reducing end (1413) with the first connecting member (142). The first fastener (151) can move in the first waist-shaped hole (104) along the length direction of the first waist-shaped hole (104). A plurality of second fasteners (152) cooperate with the second waist-shaped hole of the second reducing end (1414) to connect the second reducing end (1414) with the second connecting member (143). The second fastener (152) can move in the second waist-shaped hole along the length direction of the second waist-shaped hole.

3. The diameter-changing device according to claim 2, characterized in that: The cross section of the linkage part (141) is fan-shaped. There are six linkage parts (141), and the linkage parts (141) are spliced ​​to form a cylinder.

4. The diameter-changing device according to claim 2, characterized in that: The first driving member (12) is a conical structure, the first driving member (12) comprises a first end (121) and a second end (122), the outer diameter of the first end (121) is smaller than the outer diameter of the second end (122), the second driving member (13) is a conical structure, the second driving member (13) comprises a third end (131) and a fourth end (132), the outer diameter of the third end (131) is smaller than the outer diameter of the fourth end (132), and the third end (131) is arranged on a side of the second driving member (13) close to the first end (121).

5. The diameter-changing device according to claim 2, characterized in that: The first driving member (12) is a conical structure, the first driving member (12) comprises a first end (121) and a second end (122), the outer diameter of the first end (121) is smaller than the outer diameter of the second end (122), the second driving member (13) is a conical structure, the second driving member (13) comprises a third end (131) and a fourth end (132), the fourth end (132) is arranged on a side of the second driving member (13) close to the second end (122).

6. The diameter-changing device according to claim 4 or 5, characterized in that: The linkage member is provided with a plurality of linkage parts (141), each of the linkage parts (141) is circumferentially arranged around the first driving member (12) and the second driving member (13), each of the linkage parts (141) is respectively provided with a first groove (101) and a second groove (102), the first driving member (12) is provided with a plurality of first protrusions (123), each of the first protrusions (123) is respectively arranged in each of the first grooves (101), the second driving member (13) is provided with a plurality of second protrusions, each of the second protrusions is respectively arranged in each of the second grooves (102), when the first driving member (12) and the second driving member (13) are approached to or away from each other, the first protrusions (123) can move in the first groove (101), and the second protrusions can move in the second groove (102).

7. The diameter-changing device according to claim 6, characterized in that: The linkage portion (141) comprises a first sliding surface (1411) and a second sliding surface (1412); the first sliding surface (1411) and the second sliding surface (1412) are inclined in opposite directions; the first groove (101) is arranged on the first sliding surface (1411); the first driving member (12) is arranged corresponding to the first sliding surface (1411); the second groove (102) is arranged on the second sliding surface (1412); and the second driving member (13) is arranged corresponding to the second sliding surface (1412).

8. The diameter-changing device according to claim 6, characterized in that: The connecting rod (11) comprises a first thread segment and a second thread segment, wherein the spiral directions of the first thread segment and the second thread segment are opposite, the first driving member (12) is threadedly connected to the first thread segment, and the second driving member (13) is threadedly connected to the second thread segment.

9. The diameter-changing device according to claim 7 or 8, characterized in that: Both ends of the connecting rod (11) are respectively provided with clamping grooves (103), and the clamping grooves (103) are used to cooperate with a wrench to rotate the connecting rod (11).

10. The diameter-changing device according to claim 9, characterized in that: The outer diameter expansion range of the diameter-changing device (10) is 0 mm to 5 mm.

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