CN109093245B

CN109093245B - Double-drive differential stirring friction welding tool

Info

Publication number: CN109093245B
Application number: CN201811085361.5A
Authority: CN
Inventors: 王豪; 郭晓娟; 仇晓磊; 曹占山; 徐飞; 陆彦臻
Original assignee: AVIC Beijing Aeronautical Manufacturing Technology Research Institute
Current assignee: AVIC Beijing Aeronautical Manufacturing Technology Research Institute
Priority date: 2018-09-18
Filing date: 2018-09-18
Publication date: 2020-11-13
Anticipated expiration: 2038-09-18
Also published as: CN109093245A

Abstract

The invention relates to a double-drive differential stirring friction welding tool. This instrument includes stirring needle and shaft shoulder, the rotatable cover of stirring needle is established in the central through-hole of shaft shoulder, and, the tip of stirring needle surpasss the shaft shoulder tip, its characterized in that the stirring needle with the department is established to the cover of shaft shoulder tip, from the bottom up is equipped with two polar motion seal structure in proper order and arranges the material structure, two polar motion seal structure include that the labyrinth that sets gradually from the bottom up moves seal structure and screw thread and moves seal structure, it establishes to arrange the material structure the upper portion that the seal structure was moved to the screw thread is used for with the stirring head with welding clamp material in the clearance of shaft shoulder discharges and goes. Through two pole dynamic seal structures and row material through-hole, the welding material of having solved among the current friction stir welding process gets into welding tool and accumulational problem through the clearance easily.

Description

Double-drive differential stirring friction welding tool

Technical Field

The invention relates to the technical field of friction stir welding, in particular to a double-drive differential friction stir welding tool.

Background

The principle of friction stir welding is that the welding seam material is plasticized and flows along with the rotation of a stirring needle through the friction heat generation of the stirring needle and a workpiece to be welded. And forming a welding line under the action of the upsetting force of the shaft shoulder of the stirring pin. Currently, friction stir welding technology has been widely used in the aerospace, marine and rail transportation industries. As the application area expands, increasing the weld thickness is a significant challenge for the technology to continue to extend to other industries. The problem of unbalanced heat input between the end part and the root part of the stirring pin is obvious along with the increase of the thickness of the workpiece to be welded. The heat input sources for friction stir welding are mainly from two sources: friction generates heat and plastic deformation generates heat. The frictional heat generation is mainly dependent on the rotational speed of the stirring pin. The increase of the rotating speed increases the heat input at the end part of the stirring pin, and the connection of the root part of the stirring pin and the shaft shoulder causes excessive heat input and causes welding defects. To solve the problem of welding overheating, a double-drive differential friction stir welding tool was studied and developed.

The existing double-drive differential stirring friction welding tool is designed to be of a shaft shoulder and a stirring pin in a split structure. The stirring pin can rotate at a high speed, and the shaft shoulder can rotate at a low speed, so that the welding heat input of the thick plate is balanced. Due to the structural design requirement, a gap exists between the shaft shoulder and the stirring pin. The clearance mainly causes the following two problems: 1. during welding, plastic welding material is easily introduced into the interior of the welding tool through the gap and accumulates. The materials are continuously accumulated, so that the main shaft is locked when the welding distance is limited or serious. 2. After welding, the stirring pin and the shaft shoulder are adhered to each other by welding and clamping materials in the gap and cannot be detached.

Accordingly, to solve the above problems, the inventors provide a dual drive differential friction stir welding tool.

Disclosure of Invention

The embodiment of the invention provides a double-drive differential stirring friction welding tool, which solves the problem that welding materials in the existing stirring friction welding process easily enter the welding tool through gaps and are accumulated through a bipolar motion sealing structure and a discharge through hole.

The embodiment of the invention provides a double-drive differential friction stir welding tool which comprises a stirring needle and a shaft shoulder, wherein the stirring needle is rotatably sleeved in a central through hole of the shaft shoulder, and the end part of the stirring needle exceeds the end part of the shaft shoulder.

Preferably, the stirring needle with the central through-hole cooperation department of shaft shoulder tip is notch cuttype step fit clearance, labyrinth dynamic seal structure with screw thread dynamic seal structure forms notch cuttype step fit clearance for prevent that the welding presss from both sides the material and gets into from the fit clearance.

Preferably, the inner wall of the central through hole of the shaft shoulder at the end part is an annular shaft shoulder flange, and the shaft shoulder flange is in clearance fit with the outer surface of the stirring needle to form the labyrinth seal structure.

Preferably, the outer periphery of the stirring pin close to the matching position of the shaft shoulder flange is an annular stirring pin flange, and the outer surface of the stirring pin flange is provided with threads.

Preferably, an annular sunken groove is formed in the periphery of the stirring pin on the upper portion of the stirring pin flange, and one or more discharge through holes are formed in the shaft shoulder in the wall thickness direction opposite to the annular sunken groove and used for discharging welding clamping materials.

Preferably, the discharge through hole comprises a stepped hole formed by an inner hole and an outer hole, and the aperture of the inner hole is smaller than that of the outer hole.

Preferably, the stirring pin is of a conical structure, correspondingly, the central through hole of the shaft shoulder is a conical through hole, and the stirring pin of the conical structure and the conical through hole adopt a coaxial clearance fit mode.

Preferably, the end of the stirring pin is provided with a thread beyond the periphery of the conical structure of the end of the shaft shoulder.

Preferably, the rotational speed of the stirring pin is greater than the rotational speed of the shaft shoulder.

In summary, the double-pole dynamic sealing structure and the material discharging through hole structure are designed, welding clamping materials can be blocked outside a tool by the double-pole dynamic sealing structure, the welding clamping materials in gaps can be discharged by the material discharging through hole structure, the problem that the welding clamping materials easily enter the tool through gaps and are accumulated in the tool in the existing double-drive friction stir welding process is solved, the welding distance is not limited by the tool, a stirring needle and a shaft shoulder cannot be adhered, the tool is easy to disassemble, and the friction stir welding efficiency is remarkably improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic cross-sectional view of a dual drive differential friction stir welding tool according to an embodiment of the present invention.

1-a labyrinth type dynamic sealing structure; 2-a thread dynamic sealing structure; 3-annular sinking groove; 4-a discharge through hole;

10-a stirring pin; (ii) a 20-shaft shoulder.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention and are not intended to limit the scope of the invention, i.e., the invention is not limited to the embodiments described, but covers any modifications, alterations, and improvements in the parts, components, and connections without departing from the spirit of the invention.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

FIG. 1 is a schematic cross-sectional view of a dual drive differential friction stir welding tool according to an embodiment of the present invention. As shown in fig. 1, this instrument has included pin mixer 10 and shaft shoulder 20, the rotatable cover of pin mixer 10 is established in the central through-hole of shaft shoulder 20, and, the tip of pin mixer 10 surpasss the tip of shaft shoulder 20, establish the department at the cover of the tip of pin mixer 10 and shaft shoulder 20, from the bottom up is equipped with two pole dynamic seal structure (1, 2) and arranges material structure (3, 4) in proper order, wherein, two pole dynamic seal structure include labyrinth dynamic seal structure 1 and the screw dynamic seal structure 2 that set gradually from the bottom up, arrange material structure (3, 4) and establish on the upper portion of screw dynamic seal structure 2, be used for pressing from both sides the welding material in the clearance with shaft shoulder 20 with pin mixer 10 and discharge.

The matching position of the stirring pin 10 and the central through hole at the end part of the shaft shoulder 20 is a stepped step matching gap, and the labyrinth type dynamic sealing structure 1 and the thread dynamic sealing structure 2 jointly form the stepped step matching gap for preventing welding clamping materials from entering a welding tool from the matching gap.

Specifically, the inner wall of the central through hole of the shaft shoulder 20 at the end is an annular shaft shoulder flange, and the shaft shoulder flange is in clearance fit with the outer surface of the stirring pin 10 to form the labyrinth dynamic seal structure 1. Compared with a straight-tube type gap, the labyrinth type dynamic sealing structure can reduce the passing rate of welding clamping materials.

In addition, the outer circumference of the pin 10 near the shoulder flange engagement is a circular pin flange, the pin flange has threads on its outer surface, and the pin flange with threads engages with the smooth central through hole of the shoulder to form a threaded dynamic seal. The periphery of the stirring pin 10 at the upper part of the flange is provided with an annular sunken groove 3, and one or more discharge through holes 4 are formed in the shaft shoulder 20 in the wall thickness direction opposite to the annular sunken groove 3 and used for discharging welding clamping materials. Annular heavy groove 3 can reduce the extra heat that the friction of pin 10 and shaft shoulder produced, arranges material through-hole 4 and can send out the welding clamp material in the clearance, prevents inside the welding clamp material further gets into the instrument.

Through differential rotation of the shoulder 20 and pin 10, the threaded pin flange moves relative to the plain central bore of the shoulder. Meanwhile, when the friction stir welding of the embodiment adopts the anticlockwise rotating direction, the threads on the flange of the stirring pin can generate a reaction force on the welding material. During welding, the reverse thrust can reduce the welding material clamping passing speed. After the welding is finished, the reverse thrust can push out the clamping materials existing in the gap, and the function of separating the shaft shoulder 20 from the stirring pin 10 is achieved. Compared with the thrust generated by the welding upset forging force on the welding clamping materials, the bipolar sealing structure cannot completely prevent the welding clamping materials from entering the tool. For the clamping materials entering the tool, the welding clamping materials are discharged from the discharge through hole 4 mainly under the action of the self-thrust of the welding clamping materials.

As a preferred embodiment, the discharge through-hole 4 comprises a stepped hole consisting of an inner hole and an outer hole, wherein the inner hole has a smaller diameter than the outer hole. The advantage of the small inner bore is that the discharge resistance can be reduced, so that the excess material can be discharged from the discharge through-hole 4 as soon as possible, without the material entering the inside of the pin 10 and the shoulder 20 through the gap. The outer hole is big then can contact discharged double-layered material with the air very fast and the sclerosis fracture, makes the discharged double-layered material can not pile up in arranging the material downthehole to row material when can not influence next welding.

As another alternative, the pin 10 is a tapered structure, and correspondingly, the central through hole of the shoulder 20 is a tapered through hole, and the pin and the tapered through hole of the tapered structure are assembled in a coaxial clearance fit manner. The stirring pin 10 moves in the central through hole of the shaft shoulder 20 along the axial direction within a certain range, so that the stirring pin 10 and the shaft shoulder 20 can rotate relatively, and the rotating speed of the stirring pin 10 is greater than that of the shaft shoulder 20, thereby realizing the process operation of the double-drive differential stirring friction welding.

As an alternative embodiment, the end of the pin 10 is threaded beyond the outer circumference of the conical configuration of the end of the shoulder 20.

In conclusion, the double-drive differential friction stir welding tool disclosed by the invention has the advantages that through designing the bipolar motion sealing structure and the material discharge through hole structure, most welding clamping materials are blocked outside a gap between the stirring needle and the shaft shoulder at first, and then a small amount of welding clamping materials in the gap are discharged through the material discharge through hole structure, so that the problem that the welding clamping materials easily enter the tool through the gap and are accumulated in the welding process of the conventional double-drive friction stir welding tool is solved.

It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the drawings. Also, a detailed description of known process techniques is omitted herein for the sake of brevity.

The above description is only an example of the present application and is not limited to the present application. Various modifications and alterations to this application will become apparent to those skilled in the art without departing from the scope of this invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. The double-drive differential friction stir welding tool comprises a stirring needle and a shaft shoulder, wherein the stirring needle is rotatably sleeved in a central through hole of the shaft shoulder, the end part of the stirring needle exceeds the end part of the shaft shoulder, and the double-drive differential friction stir welding tool is characterized in that a bipolar motion sealing structure and a discharging structure are sequentially arranged at the position where the stirring needle is sleeved with the end part of the shaft shoulder from bottom to top;

the inner wall of the central through hole of the shaft shoulder at the end part is an annular shaft shoulder flange, and the shaft shoulder flange is in clearance fit with the outer surface of the stirring needle to form the labyrinth seal structure;

the periphery of the stirring pin close to the matching position of the shaft shoulder flange is an annular stirring pin flange, and the outer surface of the stirring pin flange is provided with threads;

an annular sinking groove is formed in the periphery of the stirring pin at the upper part of the stirring pin flange, and more than one discharge through hole is formed in the shaft shoulder in the wall thickness direction opposite to the annular sinking groove and used for discharging welding clamping materials;

the discharge through hole comprises a stepped hole formed by an inner hole and an outer hole, and the aperture of the inner hole is smaller than that of the outer hole.

2. The dual drive differential friction stir welding tool of claim 1 wherein the needle is engaged with the central bore at the shoulder end by a stepped step engagement gap, and the labyrinth dynamic seal and the threaded dynamic seal form the stepped step engagement gap for preventing weld material from entering the engagement gap.

3. The dual drive differential friction stir welding tool of any one of claims 1-2 wherein the pin is tapered and correspondingly the central bore of the shoulder is tapered, the pin and the tapered bore of the tapered configuration being in a coaxial clearance fit.

4. The dual drive differential friction stir welding tool of claim 3 wherein the pin end is threaded beyond the outer circumference of the tapered configuration of the shoulder end.

5. The dual drive differential friction stir welding tool of claim 3 wherein the pin has a rotational speed greater than a rotational speed of the shoulder.