JP6936608B2 - Friction stir welding method and rotary tool for friction stir welding - Google Patents

Description

The present invention relates to a friction stir welding method for joining aluminum and the like, and a rotary tool thereof, and more specifically, to a technique capable of backfilling a hole at the end of a workpiece when friction stir welding is performed.

In making the body of transportation equipment such as automobiles and railroad vehicles, resistance spot welding or rivet joining is used when joining metal materials. However, in recent years, attention has also been focused on a method of joining using friction stir welding. This is because the joints are joined in a solid phase, so the heat effect of the joints can be suppressed without melting the members, and since there is no bead formation seen in arc welding, the appearance after processing is good and post-treatment. This is because there is a merit that it becomes easy.

Patent Document 1 and Patent Document 2 disclose techniques for a friction stir point joining device and a friction stir point joining method. The friction stir welding point joining device that joins by partially stirring the object to be joined with a rotary tool is misaligned with a pin member, a shoulder member, a tool drive unit, a press-fitting reference setting unit, and a tool drive control unit. It is equipped with a quantity calculation unit. The pin member is a columnar member that rotates around an axis as the rotary tool and can move forward and backward in the axial direction. Further, the shoulder member is a cylindrical member that is arranged so as to surround the outside of the pin member, rotates around the same axis as the pin member, and can move forward and backward in the axial direction.

In addition, the tool moving unit operates the pin member and the shoulder member so as to move forward and backward along the axis, respectively. The operation of the tool movement unit is controlled by the tool movement control unit, and the deviation amount of the tip position of the pin member or the shoulder member is calculated by the position deviation amount calculation unit. With such a configuration, by controlling the press-fitting depth from the surface of the object to be joined of the pin member, the recess formed around the pin member insertion portion can be backfilled.

Japanese Unexamined Patent Publication No. 2015-18513 Japanese Patent No. 5815961

As described in Patent Document 1 and Patent Document 2, when joining by friction stir welding, there is a problem that a raised portion and a concave portion are formed on the surface of the workpiece. Although the friction stir welding is described in Patent Document 1 and Patent Document 2, the same problem occurs even in the case of linear machining or the like, a bulge is formed at the machining start end, and a dent is formed at the machining end end. Therefore, in Patent Document 1 and Patent Document 2, by controlling the positions of the pin member and the shoulder member, a process of backfilling a part of the raised portion of the workpiece to a portion where a recess is formed after processing is performed. Attempts have been made to keep the surface in good condition. It is conceivable to apply this to linear machining such as butt-joining workpieces, but there are also problems.

In Patent Document 1 and Patent Document 2, the pin member and the shoulder member arranged around the pin member are respectively rotated, but in order to perform linear machining or the like, the pin member is inserted into the workpiece while being rotated. It is necessary to move it along the joint line in that state. Therefore, bending stress is applied to the pin member. As a result, there may be a problem such as hindering the rotation of the shoulder member.

Therefore, in order to solve such a problem, the present invention provides a friction stir welding method and a friction stir welding method that can backfill the recesses generated at the processed end even when performing linear machining using friction stir welding. It is an object of the present invention to provide a rotary tool for use.

In order to achieve the above object, the friction stir welding method according to one aspect of the present invention has the following features.
(1) In the friction stir welding method of joining by stirring the machined portion of the workpiece with a rotary tool, the rotary tool is a columnar columnar that can move forward and backward in the axial direction and can rotate around the axis. A pin member, a substantially cylindrical shoulder member arranged so as to surround the outside of the pin member, and a cylindrical shape capable of advancing and retreating in the axial direction in a space formed between the shoulder member and the pin member. The sleeve member is provided, and the tip of the sleeve member is brought into contact with the surface of the workpiece in a state where the shoulder member and the pin member are housed from the tip of the sleeve member, and the pin member is rotated. The sleeve member is pushed up by a part of the work piece by advancing in the axial direction and inserting the pin member inside the work piece, and a part of the work piece is in the space. The sleeve member moves by retracting the pin member after processing the processed portion of the workpiece with the pin member, and a part of the workpiece is discharged from the space. As a result, the end portion of the processed portion of the workpiece is backfilled.

According to the aspect described in (1) above, even when wire processing such as joining is performed by the friction stir welding method, it is possible to backfill the workpiece without forming a recess at the end of the processed portion. Become. This is due to the following reasons. First, a part of the workpiece is sucked up into the space formed between the shoulder member and the pin member after the start of machining. As a result, a part of the workpiece is held around the rotating pin member. Since the recess is formed at the end of the machined part, a part of the work piece is held in the space in this way, and the work piece is held in this space when the pin member is pulled out after the work is finished. This is to backfill a part of the thing. As a result, the processed surface of the work piece can be kept good, and a good effect can be expected in terms of processing cost and the like.
(2) In the friction stir welding method according to (1), it is preferable that a pressing mechanism for pressing the sleeve member in the axial direction is provided inside the shoulder member.

According to the embodiment described in (2) above, by providing a mechanism for pushing down the sleeve member in the axial direction, it is possible to more reliably backfill the end portion of the machined portion.

Further, in order to achieve the above object, the rotary tool for friction stir welding according to another aspect of the present invention has the following features.
(3) In a friction stir welding rotary tool that joins by stirring the machined part of the work piece, a cylindrical pin member that can move forward and backward in the axial direction and can rotate around the axis, and the pin. A substantially cylindrical shoulder member arranged so as to surround the outside of the member, a cylindrical sleeve member capable of advancing and retreating in the axial direction in a space formed between the shoulder member and the pin member, and the above. A pressing mechanism for pressing the sleeve member in the axial direction is provided inside the shoulder member.

According to the aspect described in (3) above, when performing friction stir welding, it is possible to backfill the workpiece without forming a recess at the end of the processed portion. This is because a part of the work piece is held around the pin member that continues to rotate at the start of machining by moving the pin member up and down, and a part of the work piece is backfilled at the end of machining. The processed surface can be kept good.

It is sectional drawing of the rotary tool of this embodiment. (A) The state of the rotary tool of the present embodiment before the start of machining is shown. (B) The state of the rotary tool at the start of machining according to the present embodiment is shown. (C) The state of the rotary tool during machining according to the present embodiment is shown. (D) The state of the rotary tool at the end of machining according to the present embodiment is shown. It is a perspective view at the time of processing using a rotary tool of this embodiment. It is sectional drawing which shows the state from the side surface at the time of processing using the rotary tool of this embodiment. It is a side sectional view which shows the state of the friction stir welding of this embodiment.

First, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of the rotary tool of the present embodiment. The rotary tool 100 is a rotary tool for friction stir welding of workpieces such as aluminum, and includes a shoulder member 10, a pin member 20, a sleeve member 30, and the like. The shoulder member 10 is a member that comes into contact with the surface of the workpiece without rotating, and is attached to a cylindrical outer cylinder portion 11 and one end of the outer cylinder portion 11 at the tip portion 12 and the other end of the outer cylinder portion 11. It consists of three parts of the lid portion 13 to be attached. A step portion 11a is formed inside the outer cylinder portion 11.

The pin member 20 is a member called a columnar probe or pin, and the tip 20a is a metal member that is processed into a truncated cone shape and is inserted into an workpiece while rotating. A screw-shaped spiral groove is provided as needed, but the shape thereof will be omitted here. Various materials such as PCBN (cubic boron nitride sintered body), W-Re (tungsten-rhenium) alloy, cemented carbide, Ir (iridium) alloy, etc. can be considered, but the optimum material is suitable for the member to be processed. It should be chosen and is not specifically mentioned here.

The sleeve member 30 has a stepped cylindrical shape and is arranged between the shoulder member 10 and the pin member 20. A tip portion 30a is formed at one end of the sleeve member 30, a rear end surface 30c is formed at the other end, and a step portion 30b is formed in the vicinity thereof. The rear end surface 30c of the sleeve member 30 is in contact with the spring 40, and the spring 40 urges the sleeve member 30 so that the tip of the sleeve member 30 is aligned with the tip of the shoulder member 10. There is. One end of the spring 40 is arranged so as to be in contact with the rear end surface 30c of the sleeve member 30, and the other end is arranged so as to be in contact with the lid portion 13.

The sleeve member 30 is arranged in the space 50 between the shoulder member 10 and the pin member 20 so as to be able to advance and retreat in the axial direction of the pin member 20, and is urged by the spring 40 in the direction in which the sleeve member 30 protrudes. When the tip portion 12 is not in contact with the workpiece 200, the heights of the tip end portion 12 and the tip portion 30a of the sleeve member 30 are aligned as shown in FIG. The forward position of the sleeve member 30 is positioned when the step portion 11a and the step portion 30b come into contact with each other. It should be noted that it does not prevent the sleeve member 30 from being pressed by air pressure instead of the spring 40.

The rotary tool 100 has the above configuration, and the work piece is machined by rotating the pin member 20 by a rotation mechanism (not shown). Next, the procedure of the friction stir welding method using the rotary tool 100 will be described. FIG. 2A shows the state of the rotary tool 100 before the start of machining. (B) shows the state of the rotary tool 100 at the start of machining. (C) shows the state of the rotary tool 100 being machined. (D) shows the state of the rotary tool 100 at the end of machining. FIG. 2 is a cross-sectional view. The workpiece 200 is assumed to be a light metal having a low melting point such as aluminum, but it can also be applied to a steel material or a resin material.

As shown in FIG. 2A, the rotary tool 100 brings the tip portion 12 into contact with the workpiece 200. At this time, the tip 20a of the pin member 20 does not protrude from the tip 12. Further, the tip portion 30a of the sleeve member 30 is in a position aligned with the tip portion 20a of the pin member 20. That is, the tip positions of the tip portion 12, the tip end 20a of the pin member 20, and the tip end portion 30a of the sleeve member 30 are aligned. Then, while rotating the pin member 20, heating of the workpiece 200 is started, and the pin member 20 is advanced as shown in FIG. 2 (b). At this time, the portion in contact between the workpiece 200 and the pin member 20 generates heat due to friction, and the material softens and easily flows. Therefore, the sleeve member 30 retracts and at the same time, the inflow portion 200a is formed in the space 50 described later. Will be done.

Then, in that state, the rotary tool 100 is moved to process the workpiece 200. Processing is performed in the state shown in FIG. 2C, and the inflow portion 200a continues to be maintained in that state. In FIG. 2D, at the same time that the pin member 20 is pulled out, the sleeve member 30 returns to its original position, and the inflow portion 200a is pushed out toward the workpiece 200. FIG. 3 shows a perspective view during machining with the rotary tool 100. A machining mark is formed linearly on the workpiece 200, and if this is used as a machining portion P1, a machining start end P2 and a machining end end P3 are formed. At the machining start end P2, the state shown in FIG. 2B is obtained, and at the machining end end P3, the state shown in FIG. 2D is obtained. At the end of processing P3, the work piece 200 is backfilled as shown in FIG. 2 (d).

Since the friction stir welding method of the present embodiment has the above configuration, it exhibits the actions and effects described below. Specifically, for example, the friction stir welding method according to the present invention prevents the heat effect on the base material and obtains a beautiful processed surface. This is a friction stir welding method in which the workpiece 200 is joined by stirring with the rotary tool 100. The rotary tool 100 can move forward and backward in the axial direction, and is provided with a columnar pin that can rotate around the axis. The member 20, the substantially cylindrical shoulder member 10 arranged so as to surround the outside of the pin member 20, and the cylindrical body capable of advancing and retreating in the axial direction in the space 50 formed between the shoulder member 10 and the pin member 20. A sleeve member 30 having a shape is provided, and the tip of the sleeve member 30 is brought into contact with the surface of the workpiece 200 in a state where the shoulder member 10 and the pin member 20 are housed from the tip of the sleeve member 30, and the pin member is provided. By inserting the pin member 20 into the workpiece 200 by moving the 20 forward in the axial direction while rotating the sleeve member 30, the sleeve member 30 is pushed up by a part of the workpiece 200, and a part of the workpiece 200 is a space. After being held in the 50 and the processing portion P1 which is the processing portion of the workpiece 200 is processed by the pin member 20, the sleeve member 30 is moved by retracting the pin member 20, and a part of the workpiece 200 is moved. This is because the processing end end P3, which is the end portion of the processing portion P1 of the workpiece 200, is backfilled by being discharged from the space 50.

That is, when the workpiece 200 is machined by the rotary tool 100, the machining start end P2 is in the state shown in FIG. 2B, and the machining end end P3 is in the state shown in FIG. 2D. That is, the raised portion of the material is backfilled at the machining start end P2, and the inflow portion 200a is backfilled at the machining end end P3. By doing so, it is possible to end the processing without forming a recess as shown in the problem at the processing end end P3.

FIG. 4 shows a cross-sectional view of the state from the side surface during processing. When linear machining is performed with the rotary tool 100 inserted inside the workpiece 200, the workpiece 200 acts as a resistance and bending stress is generated in the pin member 20. As a result, the pin member 20 is bent as shown in FIG. In this case, the space 50 is filled with the inflow portion 200a, but the inflow portion 200a is in a relatively fluid state. Therefore, when the pin member 20 is bent, the inflow portion 200a is in a relatively fluid state. The shape will be changed. Therefore, the sleeve member 30 does not hinder the friction stir welding. Further, when the sleeve member 30 advances and pushes out the inflow portion 200a, the pin member 20 of the rotary tool 100 has been processed, so that the bending stress applied to the pin member 20 is eliminated, and the sleeve member 30 is in a state of being eliminated. Does not hinder the progress of.

FIG. 5 shows a side sectional view showing a state of friction stir welding. FIG. 5 shows an example of joining the L-shaped bracket 202 to the plate 201. The L-shaped bracket 202 is brought into contact with the back surface of the plate 201, and friction stir welding is performed with the rotary tool 100. The processed portion P1 is formed together with the L-shaped bracket 202, and is joined while being stirred by the pin member 20. Since friction stir welding is possible from the back surface of the plate 201 in this way, it is not necessary to finish the front surface. As a result, it is possible to contribute to cost reduction when forming a body of a railroad vehicle or the like.

Further, since the spring 40 for urging the sleeve member 30 is provided inside the rotary tool 100, the inflow portion 200a is pushed out at the machining end end P3, and smooth backfilling is possible. When the machining end end P3 of the machining portion P1 is reached, the pin member 20 is pulled into the rotary tool 100, but at that time, the sleeve member 30 moves forward, that is, in the direction of being pulled out in relation to the workpiece 200. It is considered that the inflow portion 200a exits from the space 50 even if the spring 40 is not provided, because the force acts on the sleeve member 30, but this operation can be performed more smoothly by urging the sleeve member 30 with the spring 40. Be expected.

Although the embodiment of the friction stir welding method according to the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the rotary tool 100 is provided with a spring 40 to urge the sleeve member 30, but this does not prevent the rotary tool 100 from being replaced with another mechanism such as urging by air pressure. Further, it can be applied to various machining without being limited to the machining examples as shown in FIG.

10 Shoulder member 11 Outer cylinder 12 Tip 13 Lid 20 Pin member 30 Sleeve member 40 Spring 100 Rotating tool

Claims (3)

In the friction stir welding method of joining by stirring the machined part of the workpiece with a rotary tool,
The rotary tool
A columnar pin member that can move forward and backward in the axial direction and can rotate around the axis,
A substantially cylindrical shoulder member arranged so as to surround the outside of the pin member, and
A cylindrical sleeve member capable of advancing and retreating in the axial direction in a space formed between the shoulder member and the pin member is provided.
At the processing start end, the tip of the sleeve member is brought into contact with the surface of the work piece in a state where the shoulder member and the pin member are housed from the tip of the sleeve member.
By inserting the pin member into the work piece by moving the pin member forward in the axial direction while rotating the pin member, the sleeve member is pushed up by a part of the work piece, and one of the work pieces. The part is held in the space and
The rotary tool is moved while a part of the workpiece is held in the space, the machining portion of the workpiece is machined with the pin member, and then the pin member is retracted at the end of machining. As a result, the sleeve member moves and a part of the work piece is discharged from the space, so that the end portion of the work piece of the work piece is backfilled.
A friction stir welding method characterized by. In the friction stir welding method according to claim 1,
A pressing mechanism for pressing the sleeve member in the axial direction is provided inside the shoulder member.
A friction stir welding method characterized by. In a friction stir welding rotary tool that joins by stirring the machined part of the work piece,
A columnar pin member that can move forward and backward in the axial direction and can rotate around the axis,
A substantially cylindrical shoulder member arranged so as to surround the outside of the pin member, and
A cylindrical sleeve member having a stepped portion in the vicinity of the rear end portion capable of advancing and retreating in the axial direction in the space formed between the shoulder member and the pin member.
A pressing mechanism for pressing the sleeve member in the axial direction is provided inside the shoulder member .
When the step portion of the sleeve member comes into contact with the inner step portion provided inside the shoulder member, the heights of the tip portion of the shoulder member and the tip portion of the sleeve member are aligned.
A rotary tool for friction stir welding.

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