JP2005211971A - Friction stir welding equipment - Google Patents

Abstract

The present invention provides a friction stir welding apparatus capable of preventing a decrease in strength of a member to be welded.
A friction stir welding apparatus includes a welding tool that is pressed and rotated by first and second welded members. The joining tool 50 includes a tool body 51 that is rotationally driven by the joining tool rotation mechanism 60, and an inner member 52 that is inserted into the tool body 51 so as to be movable in the axial direction thereof. The inner member 52 is movable in a first direction A that protrudes toward the first and second welded members 11 and 12 from the distal end surface 51a of the tool main body 51 that faces the first welded member 11. It is possible to move in the second direction B opposite to the direction A.
[Selection] Figure 3

Description

  The present invention relates to a friction stir welding apparatus used for, for example, an operation of joining two metal plates together.

  When welding members to be welded made of a metal having good thermal conductivity such as aluminum, resistance welding in which the members to be welded are melted and joined by resistance heat generation requires a lot of energy. For this reason, a spot welding device (friction stir welding device) that joins members using frictional heat has been proposed as a device for welding members to be welded with low energy and good thermal conductivity (for example, a patent) Reference 1).

  This spot bonding apparatus includes a bonding tool that rotates while being pressed by a plurality of bonded members to be bonded (welded members) and generates frictional heat with the bonded members. The joining tool has a shape integrally including a shoulder portion (tool main body) and a pin portion protruding from the tip of the shoulder portion.

The pin part is provided to increase the pressure of the rotating friction part between the member to be welded and obtain high frictional heat. When the member to be welded is melted by frictional heat, the pin part is inserted into the molten metal. Is done. The members to be joined are joined together by melting the vicinity of the pin portion by frictional heat generated by the rotation of the pin portion, and solidifying after the molten metal flows.
JP 2001-314982 A

  However, in the spot bonding apparatus, when the pin portion is pulled out from the member to be bonded after the bonding, the concave portion into which the pin has been inserted remains in the nugget of the member to be bonded. The thickness of the lower part of the recess is thinner than the surrounding area. Therefore, the concave portion causes a defect such as a crack when the load applied to the member to be welded is large, and the strength of the member to be joined after welding may be reduced.

  Therefore, the objective of this invention is providing the friction stir welding apparatus which can prevent the strength reduction of a to-be-welded member.

  In order to achieve the above object, a joining tool of the present invention includes a tool main body that is rotationally driven by a driving means, and an inner member that is inserted into the tool main body so as to be movable in the axial direction thereof. The inner member is movable in a first direction that protrudes from the tip surface facing the member to be welded of the tool main body toward the member to be welded and a second direction opposite to the first direction.

  The inner member is inserted into the member to be welded while rotating and melts the member to be welded, and then moves in the second direction in which the inner member moves away from the member to be welded while the tip surface of the tool body is in contact with the molten metal. To do. At this time, the tool main body is kept in contact with the member to be welded and rotating. For this reason, since the molten metal in the member to be welded is maintained in a molten state by frictional heat with the tool main end, a part of the molten metal flows into the trace where the inner member is retracted.

  In a preferred form of the invention, the inner member is movable to a position that is substantially flush with the tip surface of the tool body. According to this configuration, the nugget formed on the member to be welded is approximately flattened by the tool body and the inner member by moving the inner member until it is flush with the tool body after stirring the member to be welded. Is done.

  According to the first aspect of the present invention, since the formation of the recess due to the inner member being fitted into the nugget formed on the member to be welded is suppressed, the strength of the member to be welded after welding is reduced. Is suppressed.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the members to be welded can be joined to each other while further preventing the strength from being lowered.

  A friction stir welding apparatus according to a first embodiment of the present invention will be described with reference to FIGS. The friction stir welding apparatus 10 is an apparatus that joins a plurality of welded members, for example, a first welded member 11 and a second welded member 12. The first and second members to be welded 11 and 12 are each formed from, for example, an aluminum alloy having good thermal conductivity.

  The friction stir welding apparatus 10 includes a frame 20, a moving unit 30 that can move in the vertical direction with respect to the frame 20, and a moving mechanism 40 that can move the moving unit 30.

  As shown in FIG. 1, the frame 20 includes, for example, a base portion 22 that is fixed to the floor surface 21, and a housing portion 23 that is provided at the upper end portion of the base portion 22 and houses the moving mechanism 40. The base portion 22 has, for example, a substantially L shape, and is provided with a receiving portion 24 at which the first and second members to be welded 11 and 12 are overlapped and fixed in the vertical direction. In this specification, among the members to be welded, a member disposed on the upper side is referred to as a first member to be welded 11, and a member disposed on the lower side is referred to as a second member to be welded 12. A hole 23b penetrating in the horizontal direction is formed in the vertical wall 23a of the housing portion 23.

  The moving part 30 is engaged so that it can move to the up-down direction along the vertical wall 23a of the accommodating part 23, for example. In addition, the moving unit 30 has a protruding portion 31 that protrudes from the hole 23 b of the accommodating portion 23 into the accommodating portion 23. The hole 23b is formed to be larger in the vertical direction than the protruding portion 31 of the moving portion 30, and the protruding portion 31 is movable in the vertical direction within the hole 23b.

  The moving mechanism 40 includes, for example, a ball screw 41 and a first motor 42 that rotates the ball screw 41. The screw shaft 43 of the ball screw 41 is assembled in the vertical direction inside the housing portion 23. The nut 41 a of the ball screw 41 is assembled at the tip of the protruding portion 31 of the moving unit 30 and is screwed to the screw shaft 43.

  For example, a pulley 43 a is attached to the upper end portion of the screw shaft 43. For example, a pulley 42 b is attached to the upper end of the rotation shaft 42 a of the first motor 42. The pulley 43 a and the pulley 42 b are connected via a belt 44. As a result, the rotation of the first motor 42 is transmitted to the screw shaft 43 via the belt 44. Accordingly, the moving unit 30 can move in the vertical direction along the guide 30a as the first motor 42 rotates.

  The friction stir welding apparatus 10 includes a welding tool 50, a welding tool rotating mechanism 60, a moving mechanism 70, and the like. The joining tool 50 is a portion that rotates while being pressed by the first and second members to be welded 11 and 12 and generates frictional heat between the first and second members to be welded 11 and 12, and is a tool body. 51 and an inner member 52 are provided. The tool main body 51 and the inner member 52 are made of a material having a melting point higher than those of the first and second welded members 11 and 12, and are made of, for example, a metal mainly composed of iron.

  The tool main body 51 has, for example, a substantially cylindrical shape extending in the vertical direction, and has a rolling bearing 53 interposed so that the lower end thereof faces the upper surface 11a of the first welded member 11 and the axis is along the vertical direction. And is fixed to the moving part 30. That is, the tool main body 51 is fixed to the moving unit 30 so as to be freely rotatable about its axis.

  The tool main body 51 is fixed such that a front end surface 51 a facing the first member to be welded 11 protrudes below the lower surface 32 of the moving unit 30. As shown in FIG. 2, a plurality of tooth grooves (spline grooves) 54 are formed on the inner peripheral surface 51 b of the tool body 51 along the axial direction.

  As shown in FIG. 2, the inner member 52 has, for example, a cylindrical shape that extends in the vertical direction and is inserted into the inner peripheral hole of the tool main body 51, and has a plurality of side surfaces 52 a that engage with the tooth grooves 54 of the tool main body 51. This is a spline shaft in which a tooth groove (spline groove) 55 is formed. That is, the inner member 52 is engaged with the tool main body 51 by spline coupling, can move relative to the tool main body 51 along the axial direction, and can rotate integrally with the tool main body 51. it can.

  That is, the inner member 52 has a first direction A toward the first and second members to be welded 11 and 12 and a second opposite to the first direction with respect to the tip surface 51a of the tool body 51. It can move in direction B. Further, as shown in FIG. 1, the inner member 52 extends further upward than the upper end of the tool main body 51.

  The tooth grooves 54 and 55 of the tool main body 51 and the inner member 52 will be described in detail. As shown in FIG. 2, the lower end 55a of the tooth groove 55 from the front end surface 52b of the inner member 52 facing the first welded member 11. Is a predetermined distance L1. The predetermined distance L1 is formed to be longer than at least the length of the inner member 52 protruding from the tip surface 51a of the tool body 51.

  A distance L2 from the tip surface 51a of the tool body 51 to the lower end 54a of the tooth groove 54 is formed to be at least longer than L1. Thereby, the inner member 52 can move to a position where the front end surface 52 b is flush with the front end surface 51 a of the tool main body 51.

  The joining tool rotation mechanism 60 has a function of rotating the tool main body 51 around the axis. As shown in FIG. 1, the tool rotating mechanism 60 includes, for example, a second motor 61, a belt 62, pulleys 63 and 64, and the like. The second motor 61 is fixed, for example, in the vicinity of the welding tool 50 in the moving unit 30. The pulley 64 is fixed to the upper end portion of the tool main body 51, for example. The pulley 63 is fixed to the rotation shaft 61 a of the second motor 61. The pulley 64 and the pulley 63 are connected via a belt 62. Thereby, the rotation of the second motor 61 is transmitted to the tool body 51.

  The moving mechanism 70 has a function of moving the inner member 52 in the vertical direction with respect to the tool main body 51. The moving mechanism 70 includes, for example, a ball screw 71 and a third motor 73 that rotates a screw shaft 72 of the ball screw 71.

  For example, the third motor 73 is fixed to the upper portion of the moving unit 30 so that the rotation shaft 73 a of the third motor 73 is substantially parallel to the axis of the inner member 52. The upper end of the screw shaft 72 is fixed to the lower end of the rotation shaft 73 a of the third motor 73. Thereby, the rotation of the third motor 73 is transmitted to the screw shaft 72.

  The nut 71 a of the ball screw 71 is incorporated in, for example, a joint portion 74 that connects the upper end of the inner member 52 and the screw shaft 72, and is screwed into the screw shaft 72. Further, for example, a rolling bearing is incorporated in the joint portion 74. The upper end of the inner member 52 is attached to this rolling bearing. Thereby, the joining part 74 does not rotate integrally with the inner member 52, and the inner member 52 moves in the vertical direction by the operation of the third motor 73.

  Next, an example of the operation of the friction stir welding apparatus 10 will be described. In the initial state of the welding tool 50 (at the start of friction stir welding), for example, the inner member 52 protrudes from the distal end surface 51a of the tool body 51 as shown in FIG.

  First, the first and second welded members 11 and 12 are overlapped in the vertical direction and fixed to the receiving portion 24. The distance L3 from the tip surface 51a of the tool body 51 to the tip surface 52b of the inner member 52 is set to be smaller than the thickness L4 of the first and second welded members 11 and 12, for example.

  Next, the second motor 61 is operated to rotate the welding tool 50, and the first motor 42 is operated to move the moving unit 30 downward (in the direction indicated by the arrow A). For this reason, first, the inner member 52 comes into contact with the first welded member 11. Thereby, the first welded member 11 around the inner member 52 is melted by the friction between the inner member 52 and the first welded member 11.

  When the moving part 30 further moves in the direction of arrow A, the inner member 52 is inserted into the first and second welded members 11 and 12 while melting the first and second welded members 11 and 12 by frictional heat. . As shown in FIG. 4, when the tip surface 51 a of the tool main body 51 comes into contact with the first welded member 11, the operation of the first motor 42 is stopped and the movement of the moving unit 30 in the A direction is stopped. . The tip end surface 51 a of the tool main body 51 may be slightly recessed into the first welded member 11.

  During this time, the inner member 52 and the tool main body 51 are maintained in a rotating state, so that the molten metal 13 around the inner member 52 is agitated by the inner member 52. Further, the first and second members to be welded 11 and 12 are also melted by friction with the tip surface 51 a of the tool main body 51.

  When a predetermined time elapses after the tip surface 51a of the tool main body 51 comes into contact with the first welded member 11, the third motor 73 is operated, and the inner member 52 is moved upward (indicated by an arrow B) as shown in FIG. In the second direction). At this time, since the tool main body 51 is in contact with the first welded member 11 and maintained in a rotating state, the molten metal 13 inside the first and second welded members 11 and 12 is melted by frictional heat. Maintained. For this reason, the molten metal 13 flows into the trace of the movement of the inner member 52 inside the first and second welded members 11 and 12.

  The predetermined time from when the tip surface 51a of the tool body 51 abuts on the first welded member 11 to when the third motor 73 is operated is a molten metal inside the first and second welded members 11 and 12. 13 is set based on the time when the plastic flow is sufficiently performed.

  Next, as shown in FIG. 6, the operation of the third motor 73 is stopped when the front end surface 52 b of the inner member 52 is substantially flush with the front end surface 51 a of the tool main body 51. As a result, the surface 13 a of the molten metal 13 is leveled substantially flat by the both front end surfaces 51 a and 52 b of the tool main body 51 and the inner member 52.

  Next, when a predetermined time elapses, the first motor 42 is operated, and the moving unit 30 moves upward. At this time, since the molten metal 13 of the first and second members to be welded 11 and 12 does not come into contact with the joining tool 50, it is cooled and hardened. Accordingly, the first and second welded members 11 and 12 are joined to each other. It should be noted that the surface 13a of the molten metal 13 is sufficiently leveled for a predetermined time after the both end surfaces 51a, 52b of the tool body 51 and the inner member 52 are substantially flush and the first motor 42 is operated. It is set based on the time required.

  In the friction stir welding apparatus 10 configured as described above, after the welding tool 50 melts and stirs the first and second welded members 11 and 12, only the inner member 52 is first relative to the tool body 51. Move in the second direction B. At this time, the molten metal 13 of the first and second members to be welded 11 and 12 is maintained in a molten state by frictional heat with the tool body 51, so that the molten metal 13 flows into the movement trace of the inner member 52.

  In other words, the nuggets formed on the first and second welded members 11 and 12 can be prevented from forming a recess due to the inner member 52 being fitted, so that the first and second welded members after joining are joined. The strength reduction of the welding members 11 and 12 is suppressed.

  Further, the inner member 52 moves until the front end surface 52b of the tool main body 51 and the front end surface 51a of the tool main body 51 are flush with each other, so that the surface 13a of the molten metal 13 becomes both front end surfaces 51a of the tool main body 51 and the inner member 52. , 52b is leveled substantially flat. Therefore, the friction stir welding apparatus 10 can join the first and second welded members 11 and 12 while further preventing the strength from being lowered.

  Next, a friction stir welding apparatus 10 according to a second embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  FIG. 7 shows an engaged state between the tool main body 51 and the inner member 52. A key 80 is provided on the inner member 52. A key groove 81 that engages with the key 80 is formed on the inner peripheral surface 51 b of the tool body 51 along the axial direction of the tool body 51. The key 80 is engaged with a key groove 82 formed on the side surface 52 a of the inner member 52. The tool main body 51 and the inner member 52 are engaged using a key 80. A distance L5 from the front end surface 52b of the inner member 52 to the lower end 82a of the key groove 82 is formed longer than the protruding length L3 (shown in FIG. 3) of the inner member 52.

  The friction stir welding apparatus 10 according to the second embodiment configured as described above can obtain the same effects as those of the first embodiment. In the first and second embodiments, the first welded member 11 and the second welded member 12 are used as the welded members. However, the present invention is not limited to this. For example, three welded members Can also be welded.

The front view which notches and shows a part of friction stirring apparatus which concerns on the 1st Embodiment of this invention. The perspective view which shows engagement with the tool main body and inner member shown by FIG. Sectional drawing which shows a mode that the tool main body shown by FIG. 1 is stirring the 1st to-be-welded member. Sectional drawing which shows a mode that the tool main body shown by FIG. 1 is stirring the 1st to-be-welded member and the 2nd to-be-welded member. Sectional drawing which shows a mode that the inner side member shown by FIG. 1 moves to the direction away from a to-be-welded member. Sectional drawing which shows the state which moved until the front end surface of the inner member shown by FIG. 1 became flush | level with the front end surface of a tool main body. The perspective view which shows a tool main body and a part of inner member which concern on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Friction stir welding apparatus, 11 ... 1st to-be-welded member (member to be welded), 12 ... 2nd to-be-welded member (to-be-welded member), 50 ... Joining tool, 51 ... Tool main body, 51a ... Tip surface, 52 ... Inner member, A ... first direction, B ... second direction.

Claims (2)

A friction stir welding apparatus including a welding tool that is pressed and rotated by a member to be welded,
The joining tool is
A tool body that is rotationally driven by a driving means;
A first direction that is inserted into the tool body so as to be movable in the axial direction thereof, and protrudes from the tip end surface of the tool body facing the member to be welded toward the member to be welded, and the first direction. A friction stir welding apparatus, comprising: an inner member movable in a second direction opposite to the first member.   The friction stir welding apparatus according to claim 1, wherein the inner member is movable to a position that is substantially flush with the tip surface of the tool body.

Images