Friction stirring joint tool

Abstract

To provide a small-sized friction stir welding tool comprising a rotary jig to approach and separate from a member to be welded and comprising a pin inserted to the rotary jig so as to be projectable from a shoulder face of the rotary jig.SOLUTION: An amount P of pin projection from a shoulder face 38 of a rotary jig 40 of a pin 42 is adjusted by screwing a feed screw shaft 58 being rotationally driven by an electric motor 46 housed in a cylindrical main body 44. Accordingly, a friction stir welding tool 10 can be substantially downsized compared to when the amount of projection from a shoulder face of a rotary jig of a pin is adjusted using a hydraulic cylinder, since the need is eliminated for a hydraulic cylinder, a hydraulic tank for recirculating a working fluid from the hydraulic cylinder, a hydraulic pump for supplying the working fluid in the hydraulic tank to the hydraulic cylinder, a solenoid control valve for controlling the working fluid respectively from the hydraulic pump to the hydraulic cylinder, a seal mechanism for supplying hydraulic pressure to a rotary body, and the like.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a friction stir welding device used when joining workpieces by friction stir welding, and more particularly to a friction stir welding tool that can change the amount of pin protrusion from a shoulder surface depending on the combination of thicknesses of the workpieces. [Background technology]

[0002] When joining workpieces made of the same or dissimilar metals by friction stir welding (FSW), a friction stir welding tool is used that has a shoulder surface that comes into surface contact with the workpieces to generate frictional heat and soften the workpieces, and a pin that protrudes from the center of the shoulder surface and joins the workpieces by plastically deforming and kneading the joint between the workpieces to join the atoms of the workpieces. An example of such a friction stir welding tool is described in Patent Document 1.

[0003] This friction stir welding tool comprises a rotating jig that is rotated about its axis by the rotational drive of an electric motor in the operating device and that is moved upward and downward by a first cylinder in the operating device to move it closer to and away from the workpieces to be welded, and a pin that is inserted into the rotating jig so as to be able to protrude downward from the shoulder surface of the rotating jig, and whose upward protruding portion is inserted into the operating device and connected to a second hydraulic cylinder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-000901 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional friction stir welding tool described in Patent Document 1, the rotating jig is moved upward and downward by a first cylinder in the actuation device, and a pin inserted into the rotating jig can be protruded downward from the shoulder surface of the rotating jig by a second cylinder in the actuation device. However, there is no disclosure of the mechanical relationship between the rotating jig and pin, which are rotated by an electric motor in the actuation device, and the first and second hydraulic cylinders, and there was a problem in that the feasibility of the friction stir welding tool was unclear.

[0006] Furthermore, even if the above-described friction stir welding tool could be realized, it would require a first hydraulic cylinder and a second hydraulic cylinder, a hydraulic tank for returning hydraulic oil from them, a hydraulic pump for supplying the hydraulic oil in the hydraulic tank to the first hydraulic cylinder and the second hydraulic cylinder, a plurality of electromagnetic control valves for controlling the hydraulic oil from the hydraulic pump to the first hydraulic cylinder and the second hydraulic cylinder, respectively, a sealing mechanism for supplying hydraulic oil to the rotating body, and so on, which would result in a disadvantage in that the friction stir welding tool would be large.

[0007] The present invention has been made against the background of the above circumstances, and its object is to provide a small friction stir welding tool comprising a rotating jig that can be moved toward and away from the workpieces to be welded, and a pin that is inserted into the rotating jig so as to be able to protrude from the shoulder surface of the rotating jig. [Means for solving the problem]

[0008] The gist of the present invention is a friction stir welding tool comprising: (a) an axial rotating jig that can be moved toward and away from workpieces to be welded; and a pin provided on the rotating jig so as to be protruding from a shoulder surface formed at the tip of the rotating jig, the friction stir welding tool being held by a tool chuck that is driven to rotate about its axis and moves in the axial direction; (b) a cylindrical main body whose base end is held by the tool chuck and whose tip end is concentrically connected to the rotating jig; (c) an electric motor inserted within the main body so as not to be able to rotate relative to the rotating jig about its axis; and (d) a feed screw shaft that is connected to the electric motor and threadedly engages with a nut member fixed to the main body, and that passes vertically through the rotating jig; and (e) the pin is moved axially together with the tip end of the feed screw shaft, so that the amount of protrusion from the shoulder surface of the rotating jig is changed. The reason is that. [Effects of the Invention]

[0009] According to the friction stir welding tool of the present invention, the amount of protrusion of the pin from the shoulder surface of the rotating jig is adjusted by the threaded advancement of a feed screw shaft that is rotationally driven by an electric motor housed in a cylindrical main body. This eliminates the need for a hydraulic cylinder, a hydraulic tank that returns hydraulic oil from the hydraulic cylinder, a hydraulic pump that supplies hydraulic oil from the hydraulic tank to the hydraulic cylinder, electromagnetic control valves that respectively control the hydraulic oil from the hydraulic pump to the hydraulic cylinder, and a sealing mechanism that supplies hydraulic pressure to the rotor, making the friction stir welding tool significantly smaller.

[0010] Preferably, the opening at the tip of the cylindrical main body has a tapered inner circumferential surface that increases in diameter outward, the base end of the rotating jig has a tapered outer circumferential surface that fits closely to the tapered inner circumferential surface, and the base end of the rotating jig is fixed to the tip of the main body with an annular nut that is threaded onto a male thread formed on the outer circumferential surface of the tip of the cylindrical main body, thereby improving the centering accuracy between the main body and the rotating jig.

[0011] Preferably, the base end of the rotating jig has an opening at the end surface of the base end of the rotating jig and the rotating jig The rotating jig has a radial slit that penetrates from the inner peripheral surface to the outer peripheral surface of the base end thereof, and the nut member is fitted onto the inner peripheral surface of the base end thereof, so that the nut member is firmly fixed by the collet chuck structure tightened by the annular nut.

[0012] Preferably, the pin has a small diameter portion and a large diameter portion, and the rotating jig has a vertical through-hole that accommodates the feed screw shaft and into which the large diameter portion of the pin is slidably fitted so that the tip of the feed screw shaft can contact and slide, and a through-hole that penetrates the bottom surface of the vertical through-hole so that the small diameter portion protrudes from the center of the shoulder surface. As a result, the load from the workpieces applied to the pin is supported by the main body via the feed screw shaft, the annular nut to which the feed screw shaft is threaded, and the rotating jig to which the annular nut is fixed.

[0013] Preferably, a compression coil spring is inserted between the large diameter portion of the pin and the periphery of the through hole of the rotating jig, so that the pin is constantly biased toward the body by the compression coil spring, and when the feed screw shaft is moved toward the body to reduce the amount of pin protrusion, the position of the pin also moves by the amount of movement of the feed screw shaft.

[0014] Preferably, a bearing metal is fitted into the vertical through-hole of the rotating jig, into which the tip of the feed screw shaft is slidably fitted. This allows the tip of the feed screw shaft to abut against the center of the end face of the large diameter portion of the pin, thereby preferably suppressing buckling of the feed screw shaft when a load from the workpiece is applied to the pin.

[0015] Preferably, the electric motor is fitted into the main body so as to be unable to rotate about its axis but movable in the axial direction, whereby the feed screw shaft is rotated by the electric motor and moved in the axial direction, thereby adjusting the amount of pin protrusion from the shoulder surface of the rotation jig.

[0016] Preferably, the electric motor, the nut member, the feed screw shaft, and the pin are concentric with the main body and have a smaller diameter than the main body, thereby making the friction stir welding tool compact and shaped like a single rod. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram illustrating a friction stir welding apparatus including a friction stir welding tool according to an embodiment of the present invention. [Figure 2] 2 is a front view partially including a longitudinal section showing the friction stir welding tool of FIG. 1. FIG. [Figure 3] 2 is an enlarged cross-sectional view showing a tip portion of the rotating jig of FIG. 1. FIG. [Figure 4] 4 is a cross-sectional view showing the tip of the rotating jig of FIG. 1, taken along line IV-IV of FIG. 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will now be described with reference to the drawings. [Example]

[0019] 1 shows a friction stir welding apparatus 12 to which a friction stir welding tool 10 according to one embodiment of the present invention is applied. The friction stir welding apparatus 12 includes a fixed position table 14 for fixing workpieces W on a horizontal upper surface, a support column 20 movably mounted on a base 16 in the horizontal X direction and driven in the X direction by an X-direction motor 18, a Y-direction moving member 26 movably mounted on a Y-direction guide member 22 fixed to the support column 20 in the horizontal Y direction perpendicular to the X direction and driven in the Y direction by a Y-direction motor 24, a Z-direction moving member 32 movably mounted on a Z-direction guide member 28 fixed to the Y-direction moving member 26 in the vertical direction, i.e., the Z direction, and driven in the Z direction by a Z-direction motor 30, and a tool chuck 36 rotatably mounted on the Z-direction moving member 32 about an axis in the Z direction and driven to rotate about a vertical central axis by a tool drive motor 34 while holding the friction stir welding tool 10.

[0020] The friction stir welding tool 10 is equipped with a longitudinal rotary jig 40 having a shoulder surface 38 as its tip surface, which is rotated and lowered in the Z direction to come into surface contact with the workpieces W to generate frictional heat and soften the workpieces W, and a pin 42 which is moved in the X or Y direction while protruding from the center of the shoulder surface 38 toward the workpieces W, plastically deforming and kneading the joint portions of the workpieces W to bond the atoms of the workpieces W together, thereby joining the workpieces W together.

[0021] As shown in detail in Fig. 2, the friction stir welding tool 10 includes a cylindrical main body 44 whose base end (the upper end in Fig. 2) is gripped by a tool chuck 36. A longitudinal rotation jig 40, which is concentric with the axis C1 of the main body 44, is connected to the tip end of the main body 44. A longitudinal electric motor 46 is inserted into the main body 44 so as to be unable to rotate relative to the main body 44 about the axis C1 but movable in the direction of the axis C1. For example, a plurality of longitudinal guide protrusions 48 extending in the direction of the axis C1 protrude from the outer circumferential surface of the electric motor 46 and a plurality of longitudinal guide protrusions 50 extending in the direction of the axis C1 protrude from the inner circumferential surface of the main body 44, prevent the electric motor 46 from rotating relative to the axis C1 while allowing movement in the direction of the axis C1.

[0022] An opening at the tip end (lower end in FIG. 2 ) of the cylindrical main body 44 is formed with a tapered inner circumferential surface 44a whose diameter increases toward the outside, i.e., downward, of the main body 44. A tapered outer circumferential surface 40b is formed at the base end (upper end in FIG. 2 ) 40a of the rotating jig 40, which is in intimate contact with the tapered inner circumferential surface 44a. A male thread 52 is formed on the outer circumferential surface at the tip end of the main body 44. The base end 40a of the rotating jig 40 has a larger diameter than the other portions. The annular nut 54 is formed with a through hole 54a whose diameter is smaller than that of the base end 40a of the rotating jig 40. The annular nut 54 is threaded onto the male thread 52 with the rotating jig 40 inserted and the base end 40a of the rotating jig 40 engaged with the through hole 54a. This concentrically fixes the rotating jig 40 to the tip end of the main body 44.

[0023] The base end 40a of the rotating jig 40 has multiple radial slits 56 formed in the circumferential direction, for example, three slits, which open on the upper end surface of the base end 40a of the rotating jig 40 and penetrate from the inner surface to the outer surface of the base end 40a of the rotating jig 40.

[0024] A nut member 60 that screws onto a base end 58a of a feed screw shaft 58, which has an external thread formed thereon, is fitted into the opening at the base end 40a of the rotating jig 40. The tapered inner circumferential surface 44a formed in the opening that opens at the tip of the main body 44, the tapered outer circumferential surface 40b formed at the base end of the rotating jig 40 so as to closely contact the tapered inner circumferential surface 44a, the slit 56 formed in the base end 40a of the rotating jig 40, and the annular nut 54 that screws onto the male thread 52 formed on the outer circumferential surface of the tip end of the main body 44 to tighten the rotating jig 40 all function as a collet chuck that detachably fixes the nut member 60 to the main body 44.

[0025] The pin 42 has a small diameter portion 42a that protrudes from the shoulder surface 38 of the rotating jig 40 and a large diameter portion 42b that is located within the tip of the rotating jig 40. The rotating jig 40 has a vertical through-hole 62 that accommodates the feed screw shaft 58 and into which the tip of the feed screw shaft 58 is slidably fitted so as to be able to contact the large diameter portion 42b of the pin 42, and a through-hole 64 that penetrates the bottom surface of the vertical through-hole 62 so that the small diameter portion 42a protrudes from the center of the concave shoulder surface 38.

[0026] As shown in detail in FIG. 3, the vertical hole 62 has a larger diameter than the through hole 64, and a compression coil spring 66 is inserted between the large diameter portion 42b of the pin 42 and the bottom surface of the vertical hole 62 of the rotating jig 40, i.e., the peripheral edge of the through hole 64, to constantly bias the pin 42 toward the large diameter portion 42b.

[0027] Cylindrical bearing metals 68 and 69 are fitted into the vertical through-hole 64 of the rotating jig 40 and are slidably fitted into the tip and middle portions of the feed screw shaft 58. The bearing metal 68 centers and positions the tip portion of the feed screw shaft 58 so that the tip portion of the feed screw shaft 58 abuts against the center of the end face of the large-diameter portion 42b of the pin 42. The bearing metal 69 centers and positions the middle portion of the feed screw shaft 58 so that the feed screw shaft 58 remains linear even when a large axial load is applied to the feed screw shaft 58.

[0028] The pin 42 is provided so as to be non-rotatable relative to the rotating jig 40 but movable in the axial direction. For example, as shown in Fig. 4, which is a cross section taken along line IV-IV in Fig. 3, a plurality of ridges 70 each having a triangular cross section are formed in the direction of the axis C1 on the outer peripheral surface of the large diameter portion 42b of the pin 42, and a plurality of V-shaped grooves 72 for receiving the ridges 70 are formed on the inner peripheral surface of at least the lower end of the vertical through hole 62 of the rotating jig 40.

[0029] The electric motor 46, nut member 60, feed screw shaft 58, and pin 42 have a smaller diameter than the main body 44 and are concentric with the main body 44. The electric motor 46 is, for example, a servo motor, and is provided with a motor drive circuit 74 and a motor control circuit 76. The motor control circuit 76 includes, for example, a receiving module that receives a command signal transmitted from a pin protrusion amount setting operation device (not shown) that is provided in a fixed position, and controls the rotation amount of the electric motor 46 via the motor drive circuit 74 so as to obtain the pin protrusion amount P set by the pin protrusion amount setting operation device.

[0030] According to the friction stir welding tool 10 of this embodiment, the amount of pin protrusion P from the shoulder surface 38 of the rotating jig 40 of the pin 42 is adjusted by the threaded movement of the feed screw shaft 58, which is rotated by the electric motor 46 housed in the cylindrical main body 44. This eliminates the need for a hydraulic cylinder, a hydraulic tank for returning hydraulic oil from the hydraulic cylinder, a hydraulic pump for supplying hydraulic oil from the hydraulic tank to the hydraulic cylinder, electromagnetic control valves for controlling the hydraulic oil from the hydraulic pump to the hydraulic cylinder, and a seal mechanism for supplying hydraulic pressure to the rotor, making the friction stir welding tool 10 significantly smaller in size than when the amount of pin protrusion from the shoulder surface of the rotating jig is adjusted using a hydraulic cylinder.

[0031] Furthermore, according to the friction stir welding tool 10 of this embodiment, an opening at the tip of the cylindrical main body 44 is formed with a tapered inner circumferential surface 44a that becomes larger in diameter outward, and a tapered outer circumferential surface 40b that comes into close contact with the tapered inner circumferential surface 44a is formed at the base end of the rotating jig 40, and the base end of the rotating jig 40 is fixed to the tip end of the main body 44 with an annular nut 54 that is threaded onto a male thread 52 formed on the outer circumferential surface of the tip end of the main body 44. This improves the centering accuracy between the main body 44 and the rotating jig 40.

[0032] Furthermore, according to the friction stir welding tool 10 of this embodiment, a radial slit 56 is formed in the base end of the rotating jig 40, opening in the end face of the base end of the rotating jig 40 and penetrating from the inner peripheral surface to the outer peripheral surface of the base end of the rotating jig 40, and a nut member 60 is fitted onto the inner peripheral surface of the base end of the rotating jig 40. As a result, the nut member 60 is firmly fixed by a collet chuck structure formed by tightening the annular nut 54.

[0033] Furthermore, according to the friction stir welding tool 10 of this embodiment, the pin 42 has a small diameter portion 42a and a large diameter portion 42b, and the rotating jig 40 accommodates the feed screw shaft 58 and has a vertical through-hole 62 into which the tip of the feed screw shaft 58 is fitted so as to be able to contact and slide, and a through-hole 64 that penetrates the bottom surface of the vertical through-hole 62 so that the small diameter portion 42a protrudes from the center of the shoulder surface 38. As a result, the load from the workpieces W applied to the pin 42 is supported by the main body 44 via the feed screw shaft 58, the annular nut 54 to which the feed screw shaft 58 is threaded, and the rotating jig 40 to which the annular nut 52 is fixed.

[0034] Furthermore, according to the friction stir welding tool 10 of this embodiment, a compression coil spring 66 is interposed between the large diameter portion 42b of the pin 42 and the periphery of the through hole 64 of the rotating jig 40. As a result, the pin 42 is constantly urged toward the main body 44 by the compression coil spring 66, and therefore, when the feed screw shaft 58 is moved toward the main body 44 to reduce the protrusion amount P of the pin 42, the position of the pin 42 is also moved by the amount of movement of the feed screw shaft 58.

[0035] Furthermore, according to the friction stir welding tool 10 of this embodiment, the bearing metal 68, into which the tip end of the feed screw shaft 58 is slidably fitted, is fitted in the vertical through-hole 62 of the rotating jig 40. This causes the tip end of the feed screw shaft 58 to abut against the center of the end face of the large diameter portion 42b of the pin 42, so that when a load from the workpieces W is applied to the pin 42, buckling of the feed screw shaft 58 is suitably suppressed.

[0036] Furthermore, according to the friction stir welding tool 10 of this embodiment, the electric motor 46 is fitted into the main body 44 so as to be unable to rotate about its axis but movable in the axial direction. As a result, the feed screw shaft 58 is rotated by the electric motor 46, and is moved in the axial direction, thereby adjusting the amount P of pin protrusion of the pin 42 from the shoulder surface 38 of the rotating jig 40.

[0037] Furthermore, according to the friction stir welding tool 10 of this embodiment, the electric motor 46, the nut member 60, the feed screw shaft 58, and the pin 42 are concentric with the main body 44 and have a smaller diameter than the main body 44. As a result, the friction stir welding tool 10 is configured in the shape of a single rod, and is compact.

[0038] The friction stir welding tool 10 has been described above with reference to the drawings, but this is merely one embodiment of the present invention, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

[0039] For example, in the above-described embodiment, the electric motor 46 is provided so as to be movable in the axial direction but not rotatable about its axis relative to the main body 44. However, if a coupling is used between the output shaft of the electric motor 46 and the feed screw shaft 58, which connects the electric motor 46 so as to be non-rotatable about its axial direction but movable in the axial direction, the electric motor 46 may be fixed to the main body 44.

[0040] Furthermore, in the above-described embodiment, the nut member 60 is fixed to the main body 44 via the rotating jig 40, but it may also be fixed directly to the main body 44.

[0041] Furthermore, in the above-described embodiment, the bearing metals 68 and 69 were provided in the vertical through-hole 62 of the rotating jig 40, but in cases where the diameter of the feed screw shaft 58 is large and the bending strength is sufficiently high, one or both of the bearing metals 68 and 69 do not necessarily have to be provided.

[0042] Furthermore, in the above-described embodiment, the small diameter portion 42a of the pin 42 and the rotating jig 40 were arranged so as to be unable to rotate relative to each other around the axis but movable in the axial direction, but the large diameter portion 42b of the pin 42 and the rotating jig 40 may be arranged so as to be unable to rotate relative to each other around the axis but movable in the axial direction.

[0043] In addition, in the above-described embodiment, a compression coil spring 66 is provided to bias the pin 42 toward the main body 44, but instead, the feed screw shaft 58 and the pin 42 may be connected in such a way that relative rotation is permitted but relative movement in the axial direction is prevented. [Explanation of symbols]

[0044] 10:Friction stir welding tool 12:Friction stir welding equipment 38: Shoulder 40: Rotating jig 42: Pin 42a: Small diameter part 42b: Large diameter section 44: Main body 46: Electric motor 52: Male thread 54: Annular nut 54a: Through hole 56: Slit 58: Feed screw shaft 60: Nut material 62: Vertical hole 64:Through hole 66: Compression coil spring 66: Compression coil spring 68: Bearing metal

Claims

1. A friction stir welding tool comprising: an axial rotating jig that can be moved toward and away from workpieces to be welded; and a pin that is provided on the rotating jig so as to be protruding from a shoulder surface formed at the tip of the rotating jig; and the tool is gripped by a tool chuck that is driven to rotate around its axis and moves in the axial direction, a cylindrical body having a base end portion gripped by the tool chuck and a tip end portion to which the rotating jig is concentrically connected; an electric motor inserted in the main body so as to be unable to rotate relative to the main body about its axis; a feed screw shaft connected to the electric motor and threadedly passing through the rotating jig while being threadedly engaged with a nut member fixed to the main body; The pin is moved axially together with the tip of the feed screw shaft, and the amount of protrusion from the shoulder surface of the rotating jig is changed. A friction stir welding tool characterized by:

2. An opening at the tip end of the cylindrical body has a tapered inner circumferential surface whose diameter increases outward, a tapered outer circumferential surface that is in close contact with the tapered inner circumferential surface is formed at a base end of the rotating jig; The base end of the rotating jig is fixed to the tip end of the cylindrical main body by an annular nut that is threaded onto a male thread formed on the outer peripheral surface of the tip end of the main body.

2. The friction stir welding tool according to claim 1.

3. A radial slit is formed in the base end of the rotating jig, the radial slit opening on the end face of the base end of the rotating jig and penetrating from the inner peripheral surface to the outer peripheral surface of the base end of the rotating jig, The nut member is fitted onto the inner peripheral surface of the base end of the rotating jig.

2. The friction stir welding tool according to claim 1.

4. The pin has a small diameter portion and a large diameter portion, the rotating jig has a vertical through-hole that accommodates the feed screw shaft and into which the large diameter portion of the pin is slidably fitted so that the tip of the feed screw shaft can come into contact with the large diameter portion of the pin; a through hole that penetrates the bottom surface of the longitudinal hole so that the small diameter portion protrudes from the center of the shoulder surface.

2. The friction stir welding tool according to claim 1.

5. A compression coil spring is inserted between the large diameter portion of the pin and the periphery of the through hole of the rotating jig.

5. The friction stir welding tool according to claim 4.

6. A bearing metal is fitted into the vertical through-hole of the rotating jig, into which the tip of the feed screw shaft is slidably fitted.

5. The friction stir welding tool according to claim 4.

7. The electric motor, the nut member, the feed screw shaft, and the pin are concentric with the main body and have a smaller diameter than the main body.

2. The friction stir welding tool according to claim 1.

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