Welding fixture

Abstract

The application discloses a welding tool for positioning a fixing ring and a traction wire, which comprises a backing rod for the fixing ring to be sleeved thereon, a guide sleeve and a limiting sleeve coaxially and oppositely sleeved on the backing rod, a through hole for the traction wire to pass through is arranged on the guide sleeve along the axial direction of the guide sleeve, and one of the guide sleeve and the limiting sleeve is axially movable relative to the backing rod, so that the fixing ring sleeved on the backing rod can be clamped and fixed between the limiting sleeve and the guide sleeve, and the traction wire passing through the guide sleeve is matched with a welding groove on the fixing ring between the limiting sleeve and the guide sleeve. The welding tool can limit the multiple degrees of freedom of the fixing ring and the traction wire during assembly, so that the change of a welding gap is ensured, the alignment precision of the fixing ring and the traction wire is improved, and the product bending function is prevented from being invalid due to the excessively large welding gap.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of interventional medical devices, and in particular to a welding tool. BACKGROUND

[0002] In interventional therapy, catheter is the most commonly used treatment consumables. Due to the complexity of human body structure, the catheter needs to meet a certain bending angle after entering the human body to better treat diseases. The current technical means is to realize the bending of the distal end part of the catheter through a pull wire. The main principle is that the distal end of the pull wire is directly fixed on the pull ring through welding, the proximal end of the pull wire is connected with the control system, the pull wire is pulled through the control system, the force is transmitted to the pull wire, the pull wire moves relatively in the axial direction of the catheter, the force is transmitted to the pull ring arranged on the catheter through the welding point, thereby bending the elastic section of the distal end part of the catheter, and realizing the bending of the catheter.

[0003] When the distal end part of the catheter adopts an adjustable bending design, the reliability of the fixed connection between the pull ring and the pull wire determines the success or failure of the product. The most common fixing method of the existing pull wire and pull ring is welding. The pull wire and the pull ring are welded and fixed through the combination of a welding rod and manual operation. However, due to the thinness of the pull wire, the welding gap cannot be guaranteed only through the welding rod and manual operation, and the process requirement of the welding process is high, which leads to the reduction of the strength of the pull wire after welding and low reliability. In the case that the pull wire is subjected to a large pulling force or is pulled repeatedly, the welding point is prone to breakage, resulting in the failure of the bending function of the product. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a welding tool for the above-mentioned defects in the prior art.

[0005] The technical solution adopted by the present application to solve the technical problem is:

[0006] The present application provides a welding tool for positioning and fixing a ring and a traction wire. The welding tool comprises a bushing rod for sleeving the fixing ring thereon, a guide sleeve coaxially and axially sleeved on the bushing rod, and a limiting sleeve coaxially and axially sleeved on the bushing rod. A through hole is formed in the guide sleeve and penetrates the proximal end face and the distal end face of the guide sleeve, and one of the guide sleeve and the limiting sleeve is axially movable relative to the bushing rod, so that the fixing ring sleeved on the bushing rod can be clamped between the limiting sleeve and the guide sleeve, and the traction wire passing through the guide sleeve is matched with the welding groove on the fixing ring located between the limiting sleeve and the guide sleeve.

[0007] In one embodiment, the guide sleeve comprises a first sub-sleeve fixedly arranged on the bushing rod, and the through hole comprises a first sub-hole penetrating the proximal end face and the distal end face of the first sub-sleeve. The limiting sleeve is detachably connected with the bushing rod, so that the limiting sleeve is axially movable relative to the bushing rod.

[0008] In one embodiment, the guide sleeve further includes a second sub-sleeve sleeved on the liner and with its two end faces respectively opposite to the first sub-sleeve and the limiting sleeve. The through hole further includes a second sub-hole penetrating the proximal end face and the distal end face of the second sub-sleeve. The second sub-sleeve is detachably connected to the first sub-sleeve and the second sub-sleeve can only move axially relative to the first sub-sleeve. When connected, the second sub-hole is opposite to and communicates with the first sub-hole.

[0009] In one embodiment, the second sub-hole is coaxially arranged with the first sub-hole, and the diameter of the second sub-hole is smaller than the diameter of the first sub-hole.

[0010] In one embodiment, the second sub-sleeve has a notch on the side opposite to the first sub-sleeve, and the second sub-hole communicates with the notch.

[0011] In one embodiment, the inner diameter of the second sub-sleeve is smaller than the outer diameter of the fixing ring.

[0012] In one embodiment, the first sub-sleeve has a recessed connecting groove on the side opposite to the second sub-sleeve, and the second sub-sleeve has a protruding connecting protrusion on the side opposite to the first sub-sleeve. The connecting protrusion is embedded in the connecting groove and cooperates with the connecting groove.

[0013] In one embodiment, multiple connecting grooves are provided at intervals along the circumference of the first sub-sleeve, and multiple connecting protrusions are provided at intervals along the circumference of the first sub-sleeve, with each of the multiple connecting protrusions cooperating with one of the multiple connecting grooves.

[0014] In one embodiment, when the limiting sleeve can move axially relative to the liner, the outer peripheral wall of the liner is provided with an external thread, the inner hole of the limiting sleeve is provided with an internal thread, and the limiting sleeve is threadedly connected to the liner.

[0015] In one embodiment, the limiting sleeve has a limiting groove that does not penetrate the outer peripheral wall of the limiting sleeve, allowing the fixing ring to be inserted. The axial length of the limiting groove is greater than the distance from the bottom wall of the welding groove of the fixing ring to its distal end.

[0016] In one embodiment, the liner includes a first section that sleeves the fixing ring and the guide sleeve, and a second section that sleeves the limiting sleeve, with the external thread provided on the second section.

[0017] In summary, the welding fixture of the present invention can limit multiple degrees of freedom of the fixing ring and the traction wire during the assembly process to ensure the variation of the welding gap, improve the alignment accuracy of the fixing ring and the traction wire, and avoid the failure of the product bending function due to excessive welding gap. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0019] Figure 1 This is a schematic diagram of the existing fixing ring and traction wire;

[0020] Figure 2 This is an overall schematic diagram of an exemplary welding fixture of the present invention; wherein, the overall schematic diagram shows a retaining ring and a traction wire;

[0021] Figure 3 yes Figure 2 An explosion diagram;

[0022] Figure 4 This is a front view of the welding fixture positioning and fixing ring and traction wire, which are exemplary components of the present invention.

[0023] Figure 5 yes Figure 4 A cross-sectional view of section AA; wherein the cross-sectional view contains a partially magnified portion;

[0024] Figure 6 This is a schematic diagram of the structure of the limiting sleeve in the welding fixture of the present invention;

[0025] Figure 7 This is a schematic diagram of the structure after using the welding fixture positioning and fixing ring and traction wire of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this disclosure and to fully convey the scope of this disclosure to those skilled in the art.

[0027] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0028] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0029] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0030] Additionally, it should be noted that in the field of interventional medical devices, the end of a medical device implanted in the human or animal body, or the delivery system that delivers the medical device, closer to the operator is generally referred to as the "proximal end," and the end farther from the operator is referred to as the "distal end." Based on this principle, the "proximal end" and "distal end" of any component of a medical device or delivery system are defined. "Axial direction" generally refers to the length direction of the medical device during delivery, and "radial direction" generally refers to the direction of the medical device perpendicular to its "axial direction." Based on this principle, the "axial direction" and "radial direction" of any component of a medical device are defined.

[0031] Given that the welding fixture 100 of this embodiment is mainly used to position the fixed ring a and the traction wire during the welding process, before providing a specific implementation of the welding fixture 100 of this application, this embodiment provides an exemplary description of the existing structure of the fixed ring a and the traction wire. It should be noted that the structure of the fixed ring a and the traction wire described in this example is not limited thereto.

[0032] See Figure 1 As shown, the fixing ring a includes a ring body a1. A welding groove a2 is recessed on one side of the ring body a1 near its proximal end. During welding, a traction wire b needs to be inserted into the welding groove a2 to cooperate with the ring body a1. For example, the material of the traction wire is stainless steel and / or nickel-titanium alloy and / or other steel. Generally, in the process of achieving bidirectional bending, two welding grooves a2 are provided on the ring body a1, and two traction wires b are provided correspondingly, with the distal ends of the two traction wires b respectively embedded in the two welding grooves a2. It should be noted that the number and arrangement of the welding grooves a2 and the traction wires are not limited to this.

[0033] See Figure 2 As shown, the present invention provides a welding fixture 100, which is used to perform high-precision positioning and fixing of the fixing ring a and the traction wire b during the welding process, thereby improving the welding strength and ensuring product reliability.

[0034] Reference Figures 2 to 4As shown, the welding fixture 100 includes a liner 10, a guide sleeve 20, and a limiting sleeve 30. The guide sleeve 20 and the limiting sleeve 30 are coaxially and axially oppositely sleeved on the liner 10, and one of the guide sleeve 20 and the limiting sleeve 30 can move axially relative to the liner 10. The guide sleeve 20 has a through hole 20a along its axial direction, which allows the traction wire to pass through the proximal end face and the distal end face of the guide sleeve 20. The axial movement of one of the guide sleeve 20 and the limiting sleeve 30 relative to the liner 10 includes: the guide sleeve 20 can move axially relative to the liner 10 while the limiting sleeve 30 is fixed relative to the liner 10; or the limiting sleeve 30 can move axially relative to the liner 10 while the guide sleeve 20 is fixed relative to the liner 10; or both the guide sleeve 20 and the limiting sleeve 30 can move axially relative to the liner 10. It should be noted that in this embodiment, "axially movable relative to the liner 10" refers to axial movement under the action of external force, while being fixed relative to the liner 10 when no external force is applied. In addition, the shape of the through hole 20a can be determined according to the shape of the traction wire.

[0035] During the welding process, the guide sleeve 20 and / or the limiting sleeve 30, which can move axially relative to the liner 10, are moved until they are detached from the liner 10. The fixing ring a is then fitted onto the liner 10, and the guide sleeve 20 and / or the limiting sleeve 30, which are detached from the liner 10, are moved again, so that the fixing ring a fitted onto the liner 10 can be clamped and fixed between the limiting sleeve 30 and the guide sleeve 20. At this time, the traction wire passing through the guide sleeve 20 engages with the welding groove a2 on the fixing ring a located between the limiting sleeve 30 and the guide sleeve 20.

[0036] In this embodiment, for ease of installation, the limiting sleeve 30 is axially movable relative to the liner 10 while the guide sleeve 20 is fixed relative to the liner 10. This method avoids the need for the guide sleeve 20 to move with the traction wire during adjustment. Preferably, the guide sleeve 20 can be fixed relative to the liner 10 in such a way that the guide sleeve 20 and the liner 10 are integrally formed as a single component.

[0037] Continue to refer to Figures 2 to 4 As shown, as a way to fix the guide sleeve 20 and the liner 10 relative to each other, the guide sleeve 20 includes a first sub-sleeve 21 fixed on the liner 10. For example, the first sub-sleeve 21 and the liner 10 are integrally formed and can be used as a single component. The through hole 20a includes a first sub-hole 21a that axially penetrates the proximal end face and the distal end face of the first sub-sleeve 21, through which the traction wire b can pass. Preferably, in order to facilitate the insertion of the traction wire b into the first sub-hole 21a, the first sub-sleeve 21 is coaxially sleeved and fixed to one end of the liner 10. In this embodiment, the fixing ring a sleeved on the liner 10 can be clamped and fixed between the limiting sleeve 30 and the first sub-sleeve 21. At this time, the traction wire b passing through the first sub-hole 21a on the first sub-sleeve 21 cooperates with the welding groove a2 of the fixing ring a located between the limiting sleeve 30 and the first sub-sleeve 21.

[0038] In another embodiment, the guide sleeve 20 further includes a second sub-sleeve 22 sleeved on the liner 10, with its two end faces respectively opposite to the first sub-sleeve 21 and the limiting sleeve 30. The through hole 20a further includes a second sub-hole 22a axially penetrating the proximal and distal end faces of the second sub-sleeve 22, through which the traction wire b can pass. The second sub-sleeve 22 is detachably connected to the first sub-sleeve 21, and the second sub-sleeve 22 can only move axially relative to the first sub-sleeve 21. When connected, the second sub-hole 22a is opposite to and communicates with the first sub-hole 21a. That is, in this embodiment, the guide sleeve 20 includes two parts: a first sub-sleeve 21 fixed on the liner 10 and a second sub-sleeve 22 detachably connected to the first sub-sleeve 21 and axially movable. For example, the inner diameter of the second sub-sleeve 22 is smaller than the outer diameter of the fixing ring a, so that the two opposing surfaces of the second sub-sleeve 22 sleeved on the liner 10 and the fixing ring a can abut.

[0039] In this embodiment, the guide sleeve 20 is divided into two parts, one fixed and one movable. This facilitates the machining of the through hole 20a through which the traction wire b can pass. During the actual design process, it was found that the guide sleeve 20 not only needs to provide axial guidance for the traction wire b, but also needs to prevent deformation of the traction wire b caused by impact during welding. Furthermore, the guide sleeve 20 needs to limit the traction wire b radially and circumferentially to improve accuracy. Therefore, the guide sleeve 20 needs to press and limit the fixing ring a. This requires a certain axial length for the guide sleeve 20, and the diameter of the through hole 20a on the guide sleeve 20 must be as close as possible to the diameter of the traction wire b. However, in practice, the diameter of the traction wire b is usually very small, which makes it very difficult to axially drill a small-diameter through hole 20a on the guide sleeve 20, which has a relatively long axial length. Therefore, in this embodiment, the guide sleeve 20 is divided into two parts, with one guide sleeve 20 having a relatively long axial length being divided into two sub-sleeves having shorter axial lengths. This greatly reduces the difficulty of drilling small holes in the axial direction and facilitates manufacturing. On the other hand, after the welding of the fixing ring a and the traction wire b is completed, sometimes problems such as perforation during the welding process make it difficult to remove the welded fixing ring a and traction wire b from the liner 10. That is, it is difficult to detach the welded fixing ring a and traction wire b from the liner 10. The fixing ring a usually has a thin wall and relatively weak strength. If external force is used to detach it, it will cause deformation of the fixing ring a, affecting its fit with the sheath. Therefore, in this embodiment, by moving the detachably connected second sub-sleeve 22, the welded fixing ring a and traction wire b are pushed off the liner 10. This embodiment, through this structure, not only solves the problem of difficult manufacturing processes but also cleverly solves the problem of the difficulty in detaching the welded fixing ring a and traction wire b from the liner 10. Preferably, the axial length of the second sleeve 22 is greater than the axial length of the first sleeve 21, so that there is sufficient operating space on the second sleeve 22 when disengaging from the welded retaining ring a and traction wire b by means of the second sleeve 22.

[0040] See Figure 4 and Figure 5 In this configuration, to facilitate the passage of the traction wire b through the first sub-hole 21a and the second sub-hole 22a, the first sub-hole 21a on the connected first sub-sleeve 21 and the second sub-hole 22a on the second sub-sleeve 22 are coaxially arranged. Further, in other embodiments, the diameter of the second sub-hole 22a is smaller than the diameter of the first sub-hole 21a. The larger diameter of the first sub-hole 21a on the end of the first sub-sleeve 21 facilitates the insertion of the end of the traction wire b, while the relatively smaller diameter of the second sub-hole 22a on the second sub-sleeve 22 near the fixing ring a reduces the gap between the traction wire b passing through the second sub-sleeve 22 and the wall of the second sub-sleeve 22, making it easier for the second sub-sleeve 22 to radially limit the traction wire b, thereby improving the accuracy of alignment and welding.

[0041] See Figures 2 to 5 In other embodiments, since the guide sleeve 20 is detachably configured in two parts, a notch 22c is provided on the side of the second sub-sleeve 22 opposite to the first sub-sleeve 21 in order to promptly know and judge the passage status of the traction wire b. The second sub-hole 22a is opposite to and communicates with the notch 22c. It should be understood that the notch 22c acts as a window, thus penetrating the inner and outer walls of the second sub-sleeve 22. Through the notch 22c, it is possible to quickly and clearly observe whether the traction wire b has passed through the first sub-sleeve 21 and whether it has accurately entered the second sub-hole 22a of the second sub-sleeve 22.

[0042] Combination Figure 2 and Figure 3 As shown, exemplarily, in one embodiment where the second sub-sleeve 22 is detachably connected to the first sub-sleeve 21 and the second sub-sleeve 22 can only move axially relative to the first sub-sleeve 21, a connecting groove 21b is recessed on the side of the first sub-sleeve 21 opposite to the second sub-sleeve 22, and a connecting protrusion 22b is protruded on the side of the second sub-sleeve 22 opposite to the first sub-sleeve 21. The connecting protrusion 22b is embedded in the connecting groove 21b and cooperates with the connecting groove 21b. It should be noted that this method is only one connection method and is not limited to it. For example, a groove can also be provided on the second sub-sleeve 22, and a protrusion that cooperates with the groove can be provided on the first sub-sleeve 21.

[0043] In other embodiments, to ensure the stability of the limiting position, multiple connecting grooves 21b are spaced apart circumferentially along the first sub-sleeve 21, and multiple connecting protrusions 22b are spaced apart circumferentially along the first sub-sleeve 21. Each connecting protrusion 22b engages with one of the multiple connecting grooves 21b. In this embodiment, "multiple" refers to two or more. For example, two connecting grooves 21b are spaced apart circumferentially along the first sub-sleeve 21, and two connecting protrusions 22b are spaced apart circumferentially along the first sub-sleeve 21. Each of the two connecting protrusions 22b engages with one of the two connecting grooves 21b. Preferably, the included angle between the two connecting grooves 21b and the two connecting protrusions 22b is 180°.

[0044] See Figures 2 to 5 As shown, in one embodiment where the limiting sleeve 30 can move axially relative to the liner 10, the outer peripheral wall of the liner 10 is provided with external threads, and the inner hole of the limiting sleeve 30 is provided with internal threads, and the limiting sleeve 30 is threadedly connected to the liner 10. It should be noted that this embodiment is only an illustrative example and is not limited thereto. For example, the limiting sleeve 30 can also be axially moved relative to the liner 10 under the action of external force and fixed relative to the liner 10 when no external force is applied, through a sliding groove, a sliding rail, and a locking structure.

[0045] See Figure 3As shown, to ensure the flatness of the bottom of the retaining ring a during welding, the liner 10 includes a first section 11 that sleeves the retaining ring a and the guide sleeve 20, and a second section 12 that sleeves the limiting sleeve 30, with external threads provided on the second section 12. Preferably, to ensure both smoothness and that the limiting sleeve 30 can clamp the retaining ring a during movement, the internal threads inside the limiting sleeve 30 are partially provided; the section near the retaining ring a has no internal threads, while the section away from the retaining ring a has internal threads.

[0046] See Figure 5 and Figure 6 As shown, since the two sides of the axial length are usually welded first during the welding process, there is a problem that the distal end of the traction wire b may curl up, affecting the welding accuracy. Therefore, in other embodiments, a limiting groove 30a, which is not through the outer peripheral wall of the limiting sleeve 30, is recessed on the side of the limiting sleeve 30 opposite to the guide sleeve 20, allowing the fixing ring to be embedded. The axial length L1 of the limiting groove 30a is greater than the distance L2 from the bottom wall of the welding groove of the fixing ring to its distal end. See also Figure 5 and Figure 7 As shown, this configuration allows the fixed ring a and a portion of the traction wire b on the distal side to simultaneously embed into the limiting groove 30a after the fixed ring a and traction wire b are installed. This allows the groove wall of the limiting groove 30a to radially limit the fixed ring and traction wire b. Furthermore, during the welding process, the groove wall of the limiting groove 30a can prevent the end of the traction wire b from warping up.

[0047] In actual operation, the limiting sleeve 30 can be moved axially first, so that the distal end of the fixing ring a and the distal end of the traction wire b are simultaneously embedded in the limiting groove 30a. Then, the welding groove a1 is welded to both sides of the traction wire b. After welding, the limiting sleeve 30 is moved further backward, so that only the distal end of the fixing ring b is embedded in the limiting groove 30a, while the distal end of the traction wire b is completely exposed. Then, the welding groove a1 and the distal end of the traction wire b are welded. After the distal end is welded, the limiting sleeve 30 is moved further to disengage it from the liner 10. Finally, the second sub-sleeve 22 can be moved directly or with the aid of tools, and the second sub-sleeve 22 pushes the welded fixing ring a and traction wire b away from the liner 10. The welding fixture of this embodiment, by limiting multiple degrees of freedom of the fixing ring and the traction wire b during the assembly process, ensures the change of welding gap, improves the alignment accuracy of the fixing ring and the traction wire b, and avoids the failure of the product bending function due to excessive welding gap.

[0048] The welding fixture of the present invention can limit multiple degrees of freedom of the fixing ring and the traction wire during the assembly process to ensure the variation of the welding gap, improve the alignment accuracy of the fixing ring and the traction wire, and avoid the failure of the product bending function due to excessive welding gap.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A welding fixture for positioning and fixing a ring and a traction wire, characterized in that, The device includes a retaining rod on which a fixing ring is fitted, and a guide sleeve and a limiting sleeve coaxially fitted onto the retaining rod. The guide sleeve has a through hole through the proximal and distal end faces of the guide sleeve through which a traction wire can pass. One of the guide sleeve and the limiting sleeve can move axially relative to the retaining rod, so that the fixing ring fitted onto the retaining rod can be clamped between the limiting sleeve and the guide sleeve. The traction wire passing through the guide sleeve engages with a welding groove on the fixing ring located between the limiting sleeve and the guide sleeve. The welding fixture is used to position and fix the fixing ring and the traction wire during the welding process.

2. The welding fixture according to claim 1, characterized in that, The guide sleeve includes a first sub-sleeve fixed to the liner, and the through hole includes a first sub-hole penetrating the proximal end face and the distal end face of the first sub-sleeve; the limiting sleeve is detachably and movably connected to the liner, so that the limiting sleeve can move axially relative to the liner.

3. The welding fixture according to claim 2, characterized in that, The guide sleeve further includes a second sub-sleeve sleeved on the liner and with its two end faces respectively opposite to the first sub-sleeve and the limiting sleeve. The through hole further includes a second sub-hole penetrating the proximal end face and the distal end face of the second sub-sleeve. The second sub-sleeve is detachably connected to the first sub-sleeve and the second sub-sleeve can only move axially relative to the first sub-sleeve. When connected, the second sub-hole is opposite to and communicates with the first sub-hole.

4. The welding fixture according to claim 3, characterized in that, The second sub-hole is coaxially arranged with the first sub-hole, and the diameter of the second sub-hole is smaller than the diameter of the first sub-hole.

5. The welding fixture according to claim 4, characterized in that, The second sub-sleeve has a notch on the side opposite to the first sub-sleeve, and the second sub-hole communicates with the notch.

6. The welding fixture according to claim 3, characterized in that, The inner diameter of the second sub-sleeve is smaller than the outer diameter of the fixed ring.

7. The welding fixture according to claim 3, characterized in that, The first sub-sleeve has a recessed connecting groove on the side opposite to the second sub-sleeve, and the second sub-sleeve has a protruding connecting protrusion on the side opposite to the first sub-sleeve. The connecting protrusion is embedded in the connecting groove and cooperates with the connecting groove.

8. The welding fixture according to claim 7, characterized in that, Multiple connecting grooves are provided at intervals along the circumference of the first sub-sleeve, and multiple connecting protrusions are provided at intervals along the circumference of the first sub-sleeve. Each of the multiple connecting protrusions mates with one of the multiple connecting grooves.

9. The welding fixture according to any one of claims 1 to 8, characterized in that, When the limiting sleeve can move axially relative to the liner, the outer peripheral wall of the liner is provided with an external thread, the inner hole of the limiting sleeve is provided with an internal thread, and the limiting sleeve is threadedly connected to the liner.

10. The welding fixture according to claim 9, characterized in that, The limiting sleeve has a limiting groove on the side opposite to the guide sleeve, which is not through the outer peripheral wall of the limiting sleeve, into which a fixing ring can be inserted. The axial length of the limiting groove is greater than the distance from the bottom wall of the welding groove of the fixing ring to its far end.

11. The welding fixture according to claim 9, characterized in that, The liner includes a first section that connects to the fixing ring and the guide sleeve, and a second section that connects to the limiting sleeve, with the external thread provided on the second section.

Images