CN116262279A - Welding Tooling - Google Patents

Abstract

The invention discloses a welding tool for positioning a fixed ring and a drawing wire, which comprises a liner rod for the fixed ring to be sleeved on, and a guide sleeve and a limit sleeve coaxially and axially oppositely sleeved on the liner rod , the guide sleeve is provided with a through hole along its axial direction for the passage of the pulling wire, one of the guide sleeve and the limit sleeve can move axially relative to the liner rod, so that the fixed ring sleeved on the liner rod can be It is clamped and fixed between the limit sleeve and the guide sleeve, and the pulling wire passing through the guide sleeve cooperates with the welding groove on the fixing ring between the limit sleeve and the guide sleeve. The welding tooling of the present invention can limit the multiple degrees of freedom of the fixed ring and the drawing wire during the assembly process, so as to ensure the change of the welding gap, improve the alignment accuracy of the fixing ring and the drawing wire, and avoid excessive welding gaps. As a result, the bending function of the product fails.

Description

Welding Tooling

technical field

The invention relates to the technical field of interventional medical devices, in particular to a welding tool.

Background technique

In interventional therapy, the catheter is the most commonly used treatment consumable. Due to the complex structure of the human body, the catheter needs to meet a certain bending angle after entering the human body to better treat diseases. The current technical method is to realize the bending of the distal part of the catheter through a pull wire. The main principle is: the far end of the pull wire is directly fixed on the pull ring by welding, the proximal end of the pull wire is connected to the control system, and the pull wire is pulled by the control system to The force is transmitted to the pull wire, and the pull wire moves relatively in the axial direction of the catheter, and transmits the force to the pull ring arranged on the catheter through the welding spot, thereby driving the elastic section at the distal end of the catheter to bend, thereby realizing the bending of the catheter.

When the distal part of the catheter adopts an adjustable bend design, the reliability of the fixed connection of the pull ring and the pull wire determines the success or failure of the product. The most common way to fix the existing pull wires and pull rings is welding. The pull wires and pull rings are welded and fixed by welding rods and manual methods. Gaps, and high requirements for the welding process, resulting in reduced strength and low reliability of the cable after welding. In the case of large tension or multiple pulls on the cable, the solder joints are prone to breakage, resulting in product bending Function fails.

Contents of the invention

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

The technical solution adopted by the present invention to solve its technical problems is:

A welding tool is provided, which is used for positioning the fixed ring and the drawing wire. The welding tool includes a liner rod for the fixed ring to be sleeved on, and a guide sleeve and a limiter coaxially and axially oppositely sleeved on the liner bar. The guide sleeve is provided with a through hole through the proximal end surface and the distal end surface of the guide sleeve through which the pulling wire can pass, and one of the guide sleeve and the limit sleeve can be opposite to the The liner rod moves axially, so that the fixed ring sleeved on the liner rod can be clamped between the limit sleeve and the guide sleeve, and the pulling wire passing through the guide sleeve is in contact with the guide sleeve. Fit the welding groove on the fixing ring between the limiting sleeve and the guide sleeve.

In one of the embodiments, the guide sleeve includes a first sub-sleeve fixed on the liner rod, and the through hole includes a first sub-hole passing through the proximal end surface and the distal end surface of the first sub-sleeve ; The spacer sleeve is detachably connected to the liner rod, so that the spacer sleeve can move axially relative to the liner rod.

In one of the embodiments, the guide sleeve further includes a second sub-sleeve sleeved on the liner rod and opposite to the first sub-sleeve and the limiting sleeve at both ends thereof, and the through hole It also includes a second sub-hole passing through the proximal end surface and the distal end surface of the second sub-sleeve, the second sub-sleeve is detachably connected to the first sub-sleeve, and the second sub-sleeve can only be opposite to the The first sub-sleeve moves axially, and when connected, the second sub-hole is opposite to and communicates with the first sub-hole.

In one of the embodiments, the second sub-hole is arranged coaxially with the first sub-hole, and the diameter of the second sub-hole is smaller than the diameter of the first sub-hole.

In one of the embodiments, a notch is provided on the side of the second sub-case opposite to the first sub-case, and the second sub-hole communicates with the notch.

In one of the embodiments, the inner diameter of the second sub-sleeve is smaller than the outer diameter of the fixing ring.

In one of the embodiments, the side of the first sub-sleeve opposite to the second sub-sleeve is recessed with a connecting groove, and the side of the second sub-sleeve opposite to the first sub-sleeve The protrusion is provided with a connection protrusion, and the connection protrusion is embedded in the connection groove to cooperate with the connection groove.

In one of the embodiments, a plurality of connecting grooves are arranged at intervals along the circumferential direction of the first sub-sleeve, a plurality of connecting protrusions are arranged at intervals along the circumferential direction of the first sub-sleeve, and the plurality of The connection protrusions cooperate with the plurality of connection grooves one by one.

In one of the embodiments, when the limit sleeve can move axially relative to the liner rod, the outer peripheral wall of the liner rod is provided with external threads, and the inner hole of the limit sleeve is provided with internal threads, The limiting sleeve is threadedly connected with the liner rod.

In one of the embodiments, the side of the limiting sleeve opposite to the guide sleeve is concavely provided with a limiting groove that does not pass through the outer peripheral wall of the limiting sleeve and can be embedded by a fixing ring. The axial length of the groove is greater than the distance from the bottom wall of the welding groove of the fixing ring to the distal end thereof.

In one of the embodiments, the liner rod includes a first section that is sleeved on the fixing ring and the guide sleeve and a second section that is sleeved on the limiting sleeve, and the external thread is provided on the second section .

To sum up, the welding tooling of the present invention can limit the multiple degrees of freedom of the fixing ring and the drawing wire during the assembly process, so as to ensure the change of the welding gap, improve the alignment accuracy of the fixing ring and the drawing wire, and avoid the If the welding gap is too large, the bending function of the product will fail.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Fig. 1 is the structural representation of existing fixed ring and pulling wire;

Fig. 2 is an overall schematic diagram of an exemplary welding tool of the present invention; wherein, a fixed ring and a drawing wire are shown in the overall schematic diagram;

Fig. 3 is the explosion diagram of Fig. 2;

Fig. 4 is the front view after adopting the exemplary welding tool of the present invention to locate the fixed ring and the drawing wire;

Fig. 5 is a sectional view of A-A of Fig. 4; wherein, the sectional view contains a partially enlarged part;

Fig. 6 is a structural schematic diagram of a limit sleeve in an exemplary welding tool of the present invention;

Fig. 7 is a structural schematic view of the positioning of the fixing ring and the pulling wire by using the exemplary welding tool of the present invention.

Detailed ways

In order to make the objects, technical solutions and advantages of the present invention more clear, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

It should be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be meant to include the plural forms unless the context clearly dictates otherwise. The terms "comprising", "comprising", "containing" and "having" are inclusive and thus indicate the presence of stated features, steps, operations, elements and/or parts but do not exclude the presence or addition of one or Various other features, steps, operations, elements, components, and/or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless an order of performance is specifically indicated. It should also be understood that additional or alternative steps may be used.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be referred to as These terms are limited. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

For the convenience of description, spatial relative terms may be used herein to describe the relationship of one element or feature as shown in the figures with respect to another element or feature, such as "inner", "outer", "inner". ", "Outside", "Below", "Below", "Above", "Above", etc. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "beneath" the other elements or features. feature above". Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, it should be noted that in the field of interventional medical devices, the end of the medical device implanted in the human body or animal body or the delivery system that transports the medical device that is closer to the operator is generally referred to as the "proximal end", and the distance from the operator The far end is called the "distal end", and according to this principle, the "proximal end" and "distal end" of any part of the medical device or delivery system are defined. "Axial" generally refers to the length direction of the medical device when it is being transported, and "radial" generally refers to the direction perpendicular to the "axial" of the medical device, and the "axis" of any part of the medical device is defined according to this principle to" and "radial".

In view of the fact that the welding tool 100 of this embodiment is mainly used to position the fixing ring a and the drawing wire during the welding process, therefore, before providing the specific implementation of the welding tool 100 of the present application, the existing fixing ring a a and the structure of the pulling wire are described as examples, and it should be noted that the structures of the fixing ring a and the pulling wire shown in this example are not limited thereto.

As shown in Fig. 1, the fixed ring a includes a ring body a1, and a welding groove a2 is recessed on the side of the ring body a1 close to the proximal end. During the welding process, the pulling wire b needs to be inserted into the welding groove a2 and the Body a1 cooperates. Exemplarily, the material of the pulling wire is stainless steel and/or nickel-titanium alloy and/or other steel materials. Generally, in the process of realizing two-way bending adjustment, two welding grooves a2 are provided on the ring body a1 opposite to each other, and two drawing wires b are correspondingly arranged, and the distal ends of the two drawing wires b are respectively embedded in two welding grooves a2 . It should be noted that the number and arrangement of the welding slots a2 and the drawing wires are not limited thereto.

Referring to Fig. 2, the present invention exemplarily provides a welding tool 100, which is used for high-precision positioning and fixing of the fixing ring a and the drawing wire b during the welding process, thereby improving the welding strength and ensuring product reliability .

Referring to FIGS. 2 to 4 , the welding tool 100 includes a backing rod 10 , a guide sleeve 20 and a limit sleeve 30 . The guide sleeve 20 and the limit sleeve 30 are coaxially and axially oppositely sleeved on the liner rod 10, and one of the guide sleeve 20 and the limit sleeve 30 can move axially relative to the liner rod 10, and the guide sleeve 20 moves along its axis. A through hole 20a through the proximal end surface and the distal end surface of the guide sleeve 20 through which the pulling wire can pass is provided upward. Wherein, one of the guide sleeve 20 and the limit sleeve 30 can move axially relative to the liner rod 10, including the guide sleeve 20 can move axially relative to the liner rod 10 while the limit sleeve 30 is fixed relative to the liner rod 10, or the limit sleeve 30 The guide sleeve 20 can move axially relative to the liner rod 10 while the guide sleeve 20 is fixed relative to the liner rod 10 , or both the guide sleeve 20 and the limit sleeve 30 can move axially relative to the liner rod 10 . It should be noted that the axially movable relative to the liner rod 10 in this embodiment means that it can move axially under the action of an external force, and is relatively fixed to the liner rod 10 when no external force is applied. In addition, the shape of the through hole 20a may be determined according to the shape of the pulling wire.

During the welding process, the guide sleeve 20 and/or the limit sleeve 30 that can move axially relative to the liner rod 10 are moved until they are separated from the liner rod 10, and the fixing ring a is set on the liner rod 10 and then separated from the liner rod 10 The guide sleeve 20 and/or the limit sleeve 30 move again, so that the fixed ring a sleeved on the liner rod 10 can be clamped and fixed between the limit sleeve 30 and the guide sleeve 20, and at this time pass through the guide sleeve 20 The pulling wire is matched with the welding groove a2 on the fixing ring a between the limit sleeve 30 and the guide sleeve 20 .

In this embodiment, in order to facilitate installation, the way that the limit sleeve 30 can move axially relative to the liner rod 10 and the guide sleeve 20 is fixed relative to the liner rod 10 is adopted, which avoids the need for the guide sleeve 20 to be dragged Wire moves. Preferably, the fixing method of the guide sleeve 20 relative to the liner rod 10 may be that the guide sleeve 20 is integrally arranged with the liner rod 10 , and the whole is used as a component.

Continuing to refer to Figures 2 to 4, as a way of relatively fixing the guide sleeve 20 and the liner rod 10, the guide sleeve 20 includes a first sub-sleeve 21 fixed on the liner rod 10, for example, the first sub-sleeve The sleeve 21 is integrated with the liner rod 10, and the whole can be used as a component. The through hole 20a includes a first sub-hole 21a axially penetrating through the proximal end surface and the distal end surface of the first sub-sleeve 21, and the first sub-hole 21a can pass through the pulling wire b. Preferably, in order to facilitate the insertion of the pulling wire b into the first sub-hole 21a, the first sub-sleeve 21 is coaxially sleeved and fixed on one end of the liner rod 10. In this embodiment, the fixing ring sleeved on the liner rod 10 a can be clamped and fixed between the limiting sleeve 30 and the first sub-cover 21, at this time, the drawing wire b passing through the first sub-hole 21a on the first sub-cover 21 and the pulling wire b located between the limiting sleeve 30 and the first The welding groove a2 of the fixing ring a between the sub-cases 21 fits.

In another embodiment, the guide sleeve 20 also includes a second sub-sleeve 22 sleeved on the liner rod 10 and opposite to the first sub-sleeve 21 and the limit sleeve 30 on both ends thereof, and the through hole 20a also includes an axial The second sub-hole 22a passes through the proximal end surface and the distal end surface of the second sub-sleeve 22, the second sub-hole 22a can pass through the pulling wire b, the second sub-sleeve 22 is detachably connected with the first sub-sleeve 21 and The second sub-sleeve 22 can only move axially relative to the first sub-sleeve 21 , and when connected, the second sub-hole 22 a is opposite to and communicates with the first sub-hole 21 a. That is to say, in this embodiment, the guide sleeve 20 includes two parts, a first sub-sleeve 21 fixed on the liner rod 10 and a second sub-sleeve 22 detachably connected with the first sub-sleeve 21 and movable axially. Exemplarily, the inner diameter of the second sub-sleeve 22 is smaller than the outer diameter of the fixing ring a, so that two opposite surfaces of the second sub-sleeve 22 sleeved on the liner rod 10 and the fixing ring a can abut against each other.

In this embodiment, the guide sleeve 20 is divided into two and one fixed and one movable are arranged. On the one hand, it is convenient to process the through hole 20a through which the pulling wire b can pass. Because it is found in the actual design process that the guide sleeve 20 not only needs to realize the axial guiding effect on the drawing wire b, but also needs to use the guide sleeve 20 to avoid the deformation of the drawing wire b caused by the impact in the welding process, and also needs to use the guide The sleeve 20 limits the radial and circumferential positions of the pulling wire b to improve the accuracy. Therefore, it is necessary to use the guide sleeve 20 to press and limit the fixed ring a. Then the guide sleeve 20 needs a certain axial length, and also It is necessary to make the aperture of the through hole 20a opened on the guide sleeve 20 as close as possible to the diameter of the drawing wire b, but in practice the diameter of the drawing wire b is usually very small, which leads to a larger diameter on the guide sleeve 20 with a longer axial length. It is very difficult to open the through hole 20a with a small diameter in the axial direction. For this reason, the present embodiment divides the guide sleeve 20 into two, so that a guide sleeve 20 with a longer axial length is divided into two sub-sleeves with a relatively long axial length, thereby greatly reducing the The difficulty of opening small holes in the axial direction is convenient for production and processing. On the other hand, after the welding of the fixing ring a and the drawing wire b is completed, sometimes it is difficult to remove the welded fixing ring a and drawing wire b from the liner bar 10 due to problems such as perforation in the welding process, that is, it is difficult to The welded fixing ring a and pulling wire b are detached from the backing rod 10, and the fixing ring a is usually thin and its strength is relatively weak. If external force is used to detach, the fixing ring a will be deformed and affect the cooperation with the sheath . So far, in this embodiment, by moving the detachably connected second sub-sleeve 22 , the welded fixing ring a and pulling wire b are pushed away from the liner bar 10 through the second sub-sleeve 22 . Through this structure, this embodiment not only solves the problem of difficult process, but also cleverly solves the problem of the difficulty in detaching the welded fixing ring a and drawing wire b from the liner rod 10 . Preferably, the axial length of the second sub-sleeve 22 is greater than the axial length of the first sub-sleeve 21, so that when the second sub-sleeve 22 breaks away from the welded fixing ring a and the pulling wire b, the second sub-sleeve 22 There can be enough room to operate.

Referring to Fig. 4 and Fig. 5, wherein, in order to facilitate the pulling wire b to pass through the first sub-hole 21a and the second sub-hole 22a, the first sub-hole 21a on the connected first sub-case 21 and the second sub-case 22 The second sub-hole 22a is 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 first sub-hole 21a on the first sub-sleeve 21 located at the end has a larger aperture, which facilitates the insertion of the end of the drawing wire b, while the second sub-hole 22a on the second sub-sleeve 22 near the fixing ring a has a relatively smaller aperture , so that the gap between the drawing wire b passing through the second sub-sleeve 22 and the wall of the second sub-sleeve 22 is smaller, which is more conducive to the radial limitation of the second sub-sleeve 22 on the drawing wire b, thereby improving Alignment and precision during welding.

Referring to Fig. 2 to Fig. 5, in other embodiments, since the guide sleeve 20 is provided in two detachable parts, in order to be able to know and judge the passing situation of the drawing wire b in time, the second sub-sleeve 22 and the first sub-sleeve 22 A notch 22c is provided on the opposite side of the sub-case 21 , and the second sub-hole 22a is opposite to and communicated with the notch 22c. Through the gap 22c, it can be quickly and clearly observed whether the pulling wire b has passed through the first sub-case 21 and whether it has accurately penetrated into the second sub-hole 22a of the second sub-case 22 .

As shown in FIG. 2 and FIG. 3 , as an example, as an embodiment in which 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 The side of the first sub-cover 21 opposite to the second sub-cover 22 is concavely provided with a connecting groove 21b, and the side of the second sub-cover 22 opposite to the first sub-cover 21 is convexly provided with a connecting protrusion 22b. The protrusion 22b is embedded in the connecting groove 21b to cooperate with the connecting groove 21b. It should be noted that this method is only one of the connection methods, and is not limited thereto. For example, a groove may also be provided on the second sub-housing 22, and the first sub-housing 21 may be provided on the groove to fit of the bulge.

In other embodiments, in order to ensure the stability of the limit position, a plurality of connecting grooves 21b are arranged at intervals along the circumferential direction of the first sub-case 21, and a plurality of connecting protrusions 22b are arranged at intervals along the circumferential direction of the first sub-case 21, A plurality of connection protrusions 22b are matched with a plurality of connection grooves 21b one by one. Wherein, multiple in this embodiment refers to two or more than two. Exemplarily, two connecting grooves 21b are arranged at intervals along the circumferential direction of the first sub-case 21, two connecting protrusions 22b are arranged at intervals along the circumferential direction of the first sub-case 21, and the two connecting protrusions 22b are connected with two The grooves 21b fit one by one. Preferably, the included angles between the two connecting grooves 21b and the two connecting protrusions 22b are both 180°.

Referring to Figures 2 to 5, as an embodiment in which the limit sleeve 30 can move axially relative to the liner rod 10, the outer peripheral wall of the liner rod 10 is provided with external threads, and the inner hole of the limit sleeve 30 is provided with an inner thread. Thread, the limit sleeve 30 is threadedly connected with the liner rod 10. It should be noted that this embodiment is only an example and is not limited thereto. For example, the limit sleeve 30 can move axially relative to the liner rod 10 under the action of an external force by means of sliding grooves, sliding rails and locking structures. And when no external force is applied, it is relatively fixed with the liner rod 10 .

Referring to Fig. 3, in which, in order to ensure the flatness of the bottom of the fixing ring a during the welding process, the lining bar 10 includes a first section 11 which is sleeved with the fixing ring a and the guide sleeve 20, and a second section 11 which is sleeved with the limit sleeve 30. Section 12, the external thread is provided on the second section 12. Preferably, in order to ensure smoothness while ensuring that the limit sleeve 30 can clamp the fixed ring a during the movement process, the internal thread in the limit sleeve 30 is partially provided, and no internal thread is provided on a section close to the fixed ring a. An internal thread is set on a section away from the fixed ring a.

Referring to Figures 5 and 6, since the two sides of the axial length are usually welded first in the welding process, there will be a problem that the distal end of the drawing wire b is lifted, which will affect the welding accuracy. Therefore, in other embodiments The side of the limit sleeve 30 opposite to the guide sleeve 20 is recessed with a limit groove 30a that does not penetrate the outer peripheral wall of the limit sleeve 30 and can be embedded by the fixing ring. The axial length L1 of the limit groove 30a is greater than that of the fixed ring. The distance L2 from the bottom wall of the welding groove of the ring to its distal end. Referring to Fig. 5 and Fig. 7, this setting can make the fixing ring a on the distal side and a part of the pulling wire b on the distal end be embedded in the limiting groove 30a at the same time after the installation of the fixing ring a and the pulling wire b is completed. The groove wall of the limiting groove 30a can radially limit the fixing ring and the pulling wire b. In this way, during the welding process, the groove wall of the limiting groove 30a can limit the end of the drawing wire b from lifting.

In the actual operation process, the limit sleeve 30 can be moved axially first, so that the distal end of the fixed ring a and the distal end of the pulling wire b are embedded in the limit groove 30a at the same time, and then the welding groove a1 and the two ends of the pulling wire b After the welding is completed, further move the limit sleeve 30 to move backward, so that only the distal end of the fixing ring b is embedded in the limit groove 30a, and the distal end of the drawing wire b is completely exposed, and then the welding groove a1 And the far end of the pulling wire b is welded. After the welding of the distal end is completed, the spacer sleeve 30 is further moved to separate it from the liner rod 10, and finally the second sub-sleeve 22 can be moved directly or with the help of a tool, and the fixed ring a and the pulling wire after welding can be pushed through the second sub-sleeve 22 b breaks away from the liner rod 10 . The welding tooling of this embodiment, through the limitation of multiple degrees of freedom of the fixed ring and the drawing wire b during the assembly process, ensures the change of the welding gap, improves the alignment accuracy of the fixing ring and the drawing wire b, and avoids the welding gap If it is too large, the bending function of the product will fail.

The welding tooling of the present invention can limit the multiple degrees of freedom of the fixed ring and the drawing wire during the assembly process, so as to ensure the change of the welding gap, improve the alignment accuracy of the fixing ring and the drawing wire, and avoid excessive welding gaps. As a result, the bending function of the product fails.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (11)

1. A welding tool for positioning the fixed ring and the pulling wire, characterized in that it includes a liner rod for the fixed ring to be sleeved on it and a guide sleeve coaxially and axially oppositely sleeved on the liner rod and a limit sleeve, the guide sleeve is provided with a through hole through which the pulling wire can pass through the proximal end surface and the distal end surface of the guide sleeve, and one of the guide sleeve and the limit sleeve can be Move axially relative to the liner rod, so that the fixed ring sleeved on the liner rod can be sandwiched between the limit sleeve and the guide sleeve, and the pulling wire passing through the guide sleeve Cooperate with the welding groove on the fixing ring between the limit sleeve and the guide sleeve. 2. The welding tool according to claim 1, wherein the guide sleeve includes a first sub-sleeve fixed on the backing rod, and the through hole includes a proximal end surface that passes through the first sub-sleeve. and the first sub-hole on the distal end face; the spacer sleeve is detachably and movably connected to the liner rod, so that the spacer sleeve can move axially relative to the liner rod. 3. The welding tool according to claim 2, characterized in that, the guide sleeve further includes two ends sleeved on the liner rod and opposite to the first sub-sleeve and the limiting sleeve respectively. The second sub-sleeve, the through hole also includes a second sub-hole passing through the proximal end surface and the distal end surface of the second sub-sleeve, the second sub-sleeve is detachably connected to the first sub-sleeve and the The second sub-sleeve can only move axially relative to the first sub-sleeve, and when connected, the second sub-hole is opposite to and communicates with the first sub-hole. 4. The welding tool according to claim 3, wherein the second sub-hole is arranged coaxially with the first sub-hole, and the diameter of the second sub-hole is smaller than that of the first sub-hole aperture. 5 . The welding tool according to claim 4 , wherein a notch is provided on a side of the second sub-case opposite to the first sub-case, and the second sub-hole communicates with the notch. 6. The welding tool according to claim 3, wherein the inner diameter of the second sub-shell is smaller than the outer diameter of the fixing ring. 7. The welding tool according to claim 3, characterized in that, the side of the first sub-set opposite to the second sub-set is concavely provided with a connection groove, and the second sub-set is connected to the second sub-set. The opposite side of the first sub-cover is provided with a connecting protrusion, and the connecting protrusion is embedded in the connecting groove to cooperate with the connecting groove. 8. The welding tool according to claim 7, characterized in that, a plurality of connecting grooves are arranged at intervals along the circumference of the first sub-set, and the connecting protrusions are arranged along the circumference of the first sub-set. A plurality of connecting protrusions are arranged at intervals, and a plurality of connecting protrusions are matched with a plurality of connecting grooves one by one. 9. The welding tool according to any one of claims 1-8, characterized in that, when the spacer sleeve can move axially relative to the liner bar, the outer peripheral wall of the liner bar is provided with external threads, An internal thread is provided in the inner hole of the limiting sleeve, and the limiting sleeve is threadedly connected with the liner rod. 10. The welding tool according to claim 9, characterized in that, the side of the limiting sleeve opposite to the guide sleeve is concavely provided with a hole that does not pass through the outer peripheral wall of the limiting sleeve and can be embedded by a fixing ring. A limiting groove, 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. 11. The welding tool according to claim 9, characterized in that, the liner rod comprises a first section sleeved with the fixing ring and the guide sleeve and a second section sleeved with the limiting sleeve, and the outer Threads are provided on the second segment.

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