JP2012017773A - Direct acting guide bearing and friction stirring joint device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance yawing moment resistance in a compact configuration without extending the length of a slider.SOLUTION: The direct acting guide bearing 11B used as a linear guide unit of the offset axis 3 (Y axis) of the friction stirring joint device M has the linear guide rail 20, the pair of sliders 22 sandwiching the guide rail 20, and a table 23 to which the plurality of rolling bodies 25 arranged between the guide rail 20 and the rolling face B formed in the opposite surface of the respective sliders 22 and the pair of the slider 22 are fixed together, and the pair of sliders 22 are fixed to the table on which the spindle 30 of the joint tool 1 is mounted with the respective center positions in the guiding direction (Y axis) mutually displaced in the guiding direction by the guide rail 20.

Description

  The present invention relates to a linear motion guide bearing having a separation type slider and a friction stir welding apparatus using the linear motion guide bearing as a linear guide means for an offset shaft.

  As a conventional example of a linear motion guide bearing using a separation type slider, the one described in Patent Document 1 is known.

  FIG. 14 is a cross-sectional view of the linear motion guide bearing described in Patent Document 1, and FIG. 15 is a top view thereof. As shown in FIG. 14, in this linear motion guide bearing, a guide rail 210 is configured by mounting rail blocks 212 on both sides in the width direction of the base member 211, and a pair of guide rails 210 are sandwiched between the guide rails 210. A slider 220 is disposed, and both of the pair of sliders 220 are fixed to one table 230. Rolling surfaces 245A and 245B are respectively formed on the opposing surfaces of the rail block 212 and the slider 220 of the guide rail 210, and the relative movement of the slider 220 and the guide rail 210 is between the rolling surfaces 245A and 245B. A plurality of rolling elements (balls) 240 that enable the above are provided.

  The rolling elements 240 are provided in two rows for each slider 220, and the rolling elements 240 in each row circulate through circulation paths 246 formed in the respective sliders 220. The pair of sliders 220 are set to have the same length along the guide direction of the guide rail 210 and are symmetrically arranged in the width direction of the guide rail 210. The table 230 is provided with a bolt 250 for applying a preload. The bolt 250 applies a preload to the slider 220 so as to sandwich the guide rail 210.

  In Patent Document 2, by rotating the welding tool while pressing it against the workpiece, frictional heat is generated at the contact point between the welding tool and the workpiece to soften and stir the material around the contact point, thereby joining the workpiece. A friction stir welding method and apparatus are described in which a tool is immersed in a workpiece and the workpiece is linearly moved by moving the welding tool toward the surface of the workpiece after immersion.

  FIG. 16 shows a friction stir welding apparatus described in Patent Document 2. This friction stir welding apparatus includes a turning shaft 310 that rotates the welding tool 301 about its axis, a pressure shaft 320 that moves the welding tool 301 in the axial direction to approach / separate the workpiece 302, and a welding tool 301. And an offset shaft 330 that moves in the surface direction of the workpiece 302, which is a direction orthogonal to the axis of the pressing shaft 320. In this apparatus, the pressing shaft 320 is placed on the slider of the offset shaft 330 that offsets the joining tool 301, and the turning shaft 310 is placed on the slider of the pressing shaft 320.

  When joining the workpieces 302 with this friction stir welding apparatus, in the push-in operation for immersing the joining tool 301 into the workpiece 302, the joining tool 301 is pressed against the workpiece 302 by the pressure shaft 320 while rotating on the turning shaft 310, and a predetermined The joining tool 301 is immersed in the workpiece 302 to the depth. When the welding tool 301 is immersed in the workpiece 302, the pressure applied from the workpiece 302 acts on the welding tool 301 along the central axis of the welding tool 301. Note that the offset shaft 330 is stopped in the pushing operation.

  After the welding tool 301 is immersed to a predetermined depth of the workpiece 302, the pressing shaft 320 is moved slightly by stopping or holding the pressure, and the offset shaft 330 is driven to move the welding tool 301 toward the surface of the workpiece 302. Perform offset operation. In the offset operation, a pressing force is applied to the welding tool 301 from the workpiece 302, and an offset load, which is a reaction force from the workpiece 302, is opposite to the moving direction of the welding tool 301 as the welding tool 301 is offset. Acts on direction.

Japanese Patent Publication No. 1-444925 JP 2004-17128 A

  Incidentally, as shown in FIG. 15, the linear motion guide bearing described in Patent Document 1 is used when the slider 220 is used under a condition in which a yawing moment My acts on the two sliders 220 as an external load. There was a problem that the surface pressure of the rolling element increased at the end in the guiding direction, resulting in a short life. Here, the yawing moment My is perpendicular to the plane including the pair of sliders 220, and is the center between the pair of sliders 220 (that is, the center in the axial direction that is the guide direction and the width direction orthogonal to the guide direction) PH. Is a moment for rotating both sliders 220 around an axis passing through. In order to extend the life of the rolling elements, it is effective to extend the length of each slider 220. However, this increases the size of the linear motion guide device, which increases the cost and the size of the entire device. There was a connected problem.

  For example, when a linear motion guide bearing having a separation slider as shown in FIGS. 14 and 15 is used as the linear guide means of the offset shaft 330 of the friction stir welding apparatus as shown in Patent Document 2, in the offset operation, Since the yawing moment due to the applied pressure and the offset load acts on the linear guide bearing of the offset shaft 330, the surface pressure of the rolling element may increase at the end of the slider of the linear guide bearing, resulting in a short life. was there.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a linear motion guide bearing that improves yawing moment resistance in a compact form without extending the length of the slider. It is another object of the present invention to provide a friction stir welding apparatus using the linear motion guide bearing.

In order to achieve the above-described object, a linear motion guide bearing according to the invention of claim 1 includes at least one guide rail extending linearly, a pair of sliders sandwiching the guide rails, the guide rails, and the sliders. A plurality of rolling elements disposed between the rolling surfaces formed on the opposing surfaces and enabling relative movement between the sliders and the guide rail; and a table on which the pair of sliders are fixed together. ,
The pair of sliders are fixed to the table by shifting respective center positions in the guide direction by the guide rails in the guide direction.

The invention according to claim 2 is the linear motion guide bearing according to claim 1,
End caps are attached to both ends of the slider in the guiding direction,
A rolling path is formed between the rolling surface of the guide rail and the rolling surface of each slider so that the rolling element moves while rolling,
The slider and the end cap form a rolling path of the rolling element including the rolling path as a part of the path,
The rolling elements are accommodated so as to circulate through the circulation path.

In the friction stir welding apparatus according to the third aspect of the present invention, the welding tool is rotated while being pressed against the workpiece, thereby generating frictional heat at the contact point between the welding tool and the workpiece and softening the material around the contact point. A friction stir welding apparatus that stirs and thereby immerses the welding tool into the workpiece and, after immersing, moves the welding tool in the surface direction of the workpiece to join the workpiece linearly;
A pivot for rotating the welding tool about its axis;
A pressure shaft for approaching / separating the joining tool from the workpiece;
An offset shaft that moves the joining tool in the surface direction of the workpiece, which is a direction orthogonal to the axis of the pressing shaft, and
The linear motion guide bearing according to claim 1 or 2 is used as the linear guide means of the offset shaft,
The fixed side member of the linear guide means of the pressure shaft is fixed to the base, and the guide rail of the linear guide bearing is fixed on the movable side member of the linear guide means of the pressure shaft,
The pivot shaft is arranged on a table of the linear motion guide bearing.

The invention of claim 4 is the friction stir welding apparatus according to claim 3,
As the linear guide means and linear drive means of the pressure shaft,
The guide rail as the fixed side member having a substantially U-shaped cross section, the slider as the movable side member disposed in the U-shaped recess of the guide rail, the guide rail, and the slider A plurality of rolling elements disposed therebetween, wherein the guide rail has a rolling surface on an inner surface of each sleeve portion opposed to the slider, and the slider has the rolling surface of the guide rail. A rolling surface disposed opposite to the moving surface, and the rolling element is interposed between the rolling surface of the guide rail and the rolling surface of the slider, whereby the slider, the guide rail, A linear motion guide bearing that is relatively movable,
A ball screw nut formed in parallel with the guide rail, a ball screw shaft penetrating the ball screw nut, and a plurality of screws disposed between the spiral groove of the ball screw nut and the spiral groove of the ball screw shaft. A ball screw comprising a ball, and
A ball screw integrated linear motion guide unit in which the ball screw nut is provided in the slider is used.

  According to the present invention, the pair of sliders sandwiching the guide rails are arranged so that their positions are shifted from each other in the guide direction. Therefore, even when a unidirectional yawing moment acts on the table, the rolling elements at the end of the slider The surface pressure acting on the surface can be suppressed. Therefore, the yawing moment resistance can be improved without extending the lengths of the sliders separated from each other, which can contribute to the compactness of the apparatus and machine equipped with the linear motion guide bearing.

It is a side view of the friction stir welding apparatus including the linear motion guide bearing of one Embodiment of this invention. It is sectional drawing of the ball screw integrated linear motion guide unit utilized for the pressurization axis | shaft of the friction stir welding apparatus of FIG. FIG. 2 is a cross-sectional view of a linear guide bearing used as a linear guide means for an offset shaft of the friction stir welding apparatus of FIG. 1. It is a top view which shows the principal part structure of the linear motion guide bearing of FIG. It is a front view of a friction stir welding apparatus. It is a top view which shows the relationship between a pair of slider of a linear guide bearing, and the central axis of a joining tool. In a friction stir welding apparatus, it is a figure which shows distribution of the surface pressure which acts on each slider of the linear guide bearing at the time of pushing operation. In a friction stir welding apparatus, it is a figure which shows distribution of the surface pressure which acts on each slider of the linear guide bearing at the time of offset operation | movement. It is a figure which shows the comparative example with respect to embodiment of this invention, and is a top view corresponding to FIG. FIG. 10 is a diagram showing a distribution of surface pressure acting on each slider of the linear guide bearing during the pushing operation in the friction stir welding apparatus having the configuration of FIG. 9. FIG. 10 is a diagram showing a distribution of surface pressure acting on each slider of the linear guide bearing during the offset operation in the friction stir welding apparatus having the configuration of FIG. 9. It is a front view of the friction stir welding apparatus which concerns on a modification. It is a top view which shows the relationship between a pair of slider of the linear guide bearing in FIG. 12, and the central axis of a joining tool. 2 is a cross-sectional view of a linear motion guide bearing described in Patent Document 1. FIG. It is a top view of the linear guide bearing of FIG. It is a perspective view which shows an example of the friction stir welding apparatus of patent document 2. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a friction stir welding apparatus including a linear motion guide bearing according to an embodiment of the present invention, and FIG. 2 is a ball screw integrated linear motion guide used for a pressure shaft of the friction stir welding apparatus of FIG. 3 is a sectional view of a unit, FIG. 3 is a sectional view of a linear motion guide bearing used as a linear guide means for an offset shaft of the friction stir welding apparatus of FIG. 1, and FIG. FIG. 5 is a front view of the friction stir welding apparatus, and FIG. 6 is a plan view showing the relationship between a pair of sliders of the linear motion guide bearing and the central axis of the welding tool.

  As shown in FIG. 1, the friction stir welding apparatus M includes a pressurizing shaft 2 that brings a welding tool 1 for friction stir welding to approach / separate a workpiece, and the welding tool 1 is substantially orthogonal to the pressurizing shaft 2. An offset shaft 3 that moves in the direction and a pivot shaft 4 that rotates the welding tool 1 around its central axis Q (see FIG. 5) are provided. Here, the pressurizing shaft 2 is set as the X axis of the X axis and the Y axis orthogonal to each other, and the offset shaft 3 is set as the Y axis.

  As shown in FIG. 2, the pressure shaft 2 is configured by a ball screw integrated linear motion guide unit 10A, and the ball screw integrated linear motion guide unit 10A is a linear motion guide disposed along the X axis. The bearing 11A (linear guide means) and a ball screw 12A (linear drive means) are combined.

  The linear motion guide bearing 11A includes a linear guide rail 13 (fixed side member) having a substantially U-shaped cross section, and a slider 14 (movable side) disposed in a U-shaped recess of the guide rail 13. Member), and a plurality of rolling elements 15 disposed between the guide rail 13 and the slider 14. The guide rail 13 has a rolling surface 16A on the inner side surface of each sleeve portion 13A arranged to face the slider 14, and the slider 14 has a rolling surface 16B arranged to face the rolling surface 16A of the guide rail 13. A rolling element (roller in the present embodiment) 15 is interposed between the rolling surface 16A of the guide rail 13 and the rolling surface 16B of the slider 14, so that the slider 14 and the guide rail 13 are connected. Relatively linear movement is possible. In addition, you may use a ball instead of a roller as a rolling element.

  In this case, between the rolling surface 16A of the guide rail 13 and the rolling surface 16B of the slider 14, there are two rows of rolling passages 16C in which the rolling elements 15 move vertically, that is, two-to-four rows as a whole. Is done. The slider 14 is formed with a return path 16D of the rolling element 15 and a direction changing path (not shown) that connects the return path 16D and the rolling path 16 so that the rolling element 15 is connected to the rolling path 16 and the direction changing path. And an infinite circuit constituted by the return passage 16D.

  The ball screw 12A includes a ball screw nut 17 formed in parallel with the guide rail 13 of the linear guide bearing 11A, a ball screw shaft 18 passing through the ball screw nut 17, a spiral groove of the ball screw nut 17, and a ball. And a plurality of balls 19 arranged between the spiral grooves of the screw shaft 18. Then, the ball screw nut 17 which is an element of the ball screw 12A is directly formed on the slider 14 which is an element of the linear motion guide bearing 11A, so that the ball screw 12A and the linear motion guide bearing 11A are integrally provided. An integrated linear motion guide unit 10A is configured.

  The offset shaft 3 is composed of a linear motion guide bearing 11B as linear guide means shown in FIG. 3 and a ball screw unit 12B as linear drive means shown simply in FIG.

  Unlike the linear motion guide bearing 11A of the pressure shaft 2, the linear motion guide bearing 11B of the offset shaft 3 is a separation slider type, and a pair of rail blocks 21 are attached to both sides in the width direction of the base member 20A. A linear guide rail 20 configured, a pair of sliders (also referred to as bearing blocks) 22 arranged so as to sandwich the guide rail 20, and the rail blocks 21 of the guide rail 20 and the opposing surfaces of the sliders 22 A plurality of rolling elements 25 (balls in the present embodiment) disposed between the formed rolling surfaces 26A and 26B and allowing relative movement between each slider 22 and the guide rail 20, and a pair of sliders 22 are both provided. And a fixed table 23. The base member 20A of the guide rail 20 is coupled to the slider 14 of the ball screw integrated linear motion guide unit 10A constituting the pressure shaft 2 by a coupling means such as a bolt.

  End caps 28 are attached to both ends of each slider 22 in the guide direction (Y-axis direction). Further, a rolling passage 26C in which the rolling element 25 moves while rolling is formed between the rolling surface 26A of the rail block 21 and the rolling surface 26B of each slider 22, and the slider 22, the end cap 28, Thus, a rolling element circulation path 26D including the rolling passage 26 as a part of the path is formed, and the rolling element 25 is accommodated so as to circulate through the circulation path 26D. The rolling elements 25 are provided in one row for each slider 22, but may be provided in two or more rows as in the conventional example of FIG. Further, as the rolling element 25, a roller may be used instead of a ball.

  Further, as shown in FIG. 4, the pair of sliders 22 is set to have substantially the same length along the guide direction of the guide rail 20, and the center positions in the Y-axis direction are shifted from each other in the Y-axis direction to the table 23. It is fixed. A line parallel to the X axis passing through the center position of each slider 22 in the Y axis direction is defined as PA and PB, and a line parallel to the X axis direction passing through the midpoint between the lines PA and PB is defined as PX. And the distance between PX and PB are both Ls. Further, when a line parallel to the Y-axis direction passing through the intermediate point in the X-axis direction of both sliders 22 is defined as PY, an intersection PH of the line PX and the line PY is defined as the center of the linear motion guide bearing 11B.

  In the present embodiment, it is assumed that the counterclockwise yawing moment My in FIG. 4 acts on both sliders 22, and the sliders 22 are displaced from each other in the direction in which the yawing moment My acts. Specifically, as shown in FIGS. 5 and 6, both sliders 22 are aligned in the Y-axis direction, and the slider 22 closer to the welding tool 1 moves in the direction YA of the offset operation with respect to the line PX. The slider 22 that is displaced in the reverse direction by the dimension Ls and is far from the welding tool 1 is displaced by the dimension Ls in the direction in which the offset operation proceeds with respect to the line PX.

  Further, as shown in FIG. 3, the table 23 is formed in a substantially U-shaped cross section, and a pair of sliders 22 is accommodated inside sleeve portions 23A and 23A at both ends in the width direction. Between the slider 22, two tapered gibs 49 for applying a preload to the slider 22 are provided with the tapered surfaces in contact with each other. Note that a bolt may be attached to the table 23 as in the conventional example of FIG. 14, and the slider 22 may be preloaded with this bolt.

  On the other hand, unlike the case of the pressurizing shaft 2, the ball screw unit 12B, which is a linear drive means for the offset shaft 3, is provided at a location different from the linear motion guide bearing 11B. As shown in FIG. 5, the ball screw unit 12B also has a ball screw nut 17 arranged in parallel to the linear guide bearing 11B, a ball screw shaft 18 passing through the ball screw nut 17, and a spiral of the ball screw nut 17. And a plurality of balls disposed between the groove and the spiral groove of the ball screw shaft 18. The ball screw shaft 18 and the offset shaft motor 43 are attached to the table 23 side of the linear motion guide bearing 11B, and the ball screw nut 17 is provided on the guide rail 20 side of the linear motion guide bearing 11B. The ball screw unit 12B of the offset shaft 3 is driven by an offset shaft motor 43 via a belt 41B.

  Thereby, two axes of the X axis as the pressurizing shaft 2 and the Y axis as the offset shaft 3 which are orthogonal to each other are configured.

  As shown in FIG. 1, the friction stir welding apparatus M configured as described above generates frictional heat at the contact point between the welding tool 1 and the workpiece by rotating the welding tool 1 while pressing the workpiece 1 against the workpiece. The material around the contact point is softened and stirred, so that the welding tool 1 is immersed in the workpiece, and after the immersion, the workpiece is linearly moved by moving the welding tool 1 in the surface direction of the workpiece (Y-axis direction). To be joined.

  The pressing shaft 2 moves the joining tool 1 in the axial direction of the pressing shaft 2 to approach / separate the workpiece. The offset shaft 3 moves the joining tool 1 in a direction (Y axis) perpendicular to the pressing shaft 2. The guide rail 13 of the ball screw-integrated linear motion guide unit 10A constituting the pressing shaft 2 is fixed to the base end of a C-shaped arm 50 as a base via a plate 58, and the linear motion constituting the offset shaft 3 A spindle 30 on which the welding tool 1 is rotatably mounted via a bracket 48 is fixed to the table 23 of the guide bearing 11B. The slider 14 of the pressure shaft 2 is driven by a ball screw 12A of the pressure shaft 2. The ball screw shaft 18 of the pressure shaft 2 is driven by a pressure shaft motor 42 via a belt 41A.

  The welding tool 1 is rotatably held via a tool holder 35 by a spindle 30 that constitutes a turning shaft 4, and a tool base 1a that protrudes downward from a columnar tool base 1a and a shoulder 1b on the lower end surface of the tool base. A tool pin 1c having a smaller outer diameter. The spindle 30 includes a spindle housing 32 that houses the bearing 31, a bearing 31, and a spindle shaft 33 that is rotatably held by the bearing 31. The joining tool 1 is disposed on the joining tool 1 side of the spindle shaft 33. A tool holder 35 that is detachably held is provided. The spindle shaft 33 is directly connected to the turning shaft motor 44 via the coupling 34 and is driven to rotate by the turning shaft motor 44. The spindle 30 and the turning shaft motor 44 are inclined with respect to the axis of the pressure shaft 2 by fixing the bracket 48 to the table 23 of the offset shaft 3 at a predetermined inclination angle α.

  Thereby, as shown in FIG. 5, the center axis Q of the welding tool 1 passes through the center PH of the linear motion guide bearing 11B, and the inclination angle with respect to the axis of the pressure shaft 2 is α. As shown in FIG. 5, the inclination direction is a direction in which the welding tool 1 is offset (advanced) in the offset operation. By inclining the joining tool 1 in this manner, the shoulder portion 1b of the joining tool 1 can be brought into contact with the workpiece at an angle with respect to the traveling direction of the joining tool 1 during the offset operation. As a result, the fluidized workpiece material flows into the wedge portion 1b of the welding tool 1 in a wedge shape, so that the pressing force can be maintained without moving the pressing shaft 2 greatly. become.

  A pressure detection means 51 and a backing member 52 are provided at the tip of a C-shaped arm (base) 50 to which the guide rail 13 of the pressure shaft 2 is fixed. Then, by sandwiching the work between the joining tool 1 and the backing member 52, the joining tool 1 can apply pressure to the work.

Next, the relationship between the operation at the time of joining and the force acting during the operation will be described.
The welding tool 1 rotates at a high speed by driving the turning shaft motor 44. In the push-in operation for immersing the welding tool 1 into the workpiece, the pressure shaft motor 42 is driven and the ball screw shaft 18 of the pressure shaft 2 is rotated via the belt 41A, whereby the slider 14 of the pressure shaft 2 is moved. Move down. When the slider 14 of the pressure shaft 2 is moved downward, the welding tool 1 is moved downward in the X-axis direction via the offset shaft 3 and the spindle 30, and the welding tool 1 is pressed against the workpiece while rotating at high speed, The workpiece material is softened and agitated at and around the contact point. And the joining tool 1 is immersed in a workpiece | work to predetermined depth, stirring. Next, after immersing the welding tool 1 to a predetermined depth of the workpiece, an offset operation is performed while the pressure shaft 2 is finely moved along with stopping or holding the pressure.

  In the offset operation, the table 23 is moved together with the slider 22 of the offset shaft 3 by driving the offset shaft motor 43 and rotating the ball screw shaft 18 of the offset shaft 3 via the belt 41B. When the table 23 is moved, the joining tool 1 is moved in the Y axis direction (YA direction) together with the spindle 30. By this movement, the contact point and the stirring region of the joining tool 1 with respect to the workpiece move, and the workpiece is joined linearly. After moving the predetermined offset distance, the ball screw shaft 18 of the pressure shaft 2 is rotated in the opposite direction to the previous direction, so that the joining tool 1 is moved upward in the X-axis direction and detached from the workpiece. Thus, the friction stir welding is performed by the pushing operation and the offset operation.

  FIG. 7 is a diagram showing the distribution of surface pressure acting on each slider 22 of the linear guide bearing 11B of the offset shaft 3 during the pushing operation of the friction stir welding apparatus M of the present embodiment, and FIG. It is a figure which shows distribution of the surface pressure which acts on each slider 22 of the linear guide bearing 11B of the offset shaft 3 at the time of offset operation of the friction stir welding apparatus M. FIG. 9 shows an example of a friction stir welding apparatus when the positions of the pair of sliders 22 are not shifted in the Y-axis direction as a comparative example with respect to the friction stir welding apparatus M of the present embodiment. FIG. 11 is a diagram showing the distribution of surface pressure acting on each slider 22 of the offset shaft linear motion guide bearing during the pushing operation of the stir welding device, and FIG. 11 shows the linear motion guide bearing of the offset shaft when the friction stir welding device performs the offset operation. It is a figure which shows distribution of the surface pressure which acts on each slider 22 of. 7, 8 and FIGS. 10 and 11, the longer the length of the vertical line at the boundary surface between the rail block 21 and the slider 22, the higher the surface pressure.

First, the surface pressure when the friction stir welding apparatus M according to the present embodiment performs the pushing operation will be described with reference to FIG.
At the time of the pushing operation, the pressurizing force F acts as a reaction force on the slider 14 of the pressing shaft 2 along with the operation of immersing the welding tool 1 into the workpiece. The point of application of the pressure F (the central axis position of the welding tool 1) is away from the slider 22 of the offset shaft 3 in the normal direction of the attachment surface (arrow Z direction, hereinafter also referred to as the attachment surface normal direction). Therefore, a rolling moment, which is a moment about the Y axis, acts on the table 23 and the slider 22. However, since this is the same in the comparative example, the influence of the rolling moment is considered here for the sake of simplicity. Absent.

  At the time of this pushing operation (at the start of the offset operation), it is desirable that the yawing moment Mx1 (not shown) does not act on the slider 14 of the pressurizing shaft 2, so that the central axis Q of the welding tool 1 is pressurized. It is arranged so as to pass on the slider central axis of the shaft 2. That is, the axis of the pressing shaft 3 and the central axis Q of the welding tool 1 overlap each other when viewed from the direction (Z direction) perpendicular to the pressing shaft 2 and the offset shaft 3. Therefore, the center PH of the linear motion guide bearing 11 </ b> B set so as to pass on the center axis Q of the welding tool 1 is located on the axis of the pressure shaft 3. In this case, since the yawing moment Mx1 due to the applied pressure F does not act on the slider 14 of the pressurizing shaft 2, the surface pressure of the rolling element 15 is reduced at both ends of the slider at the start of the offset operation. The life of the slider 14 is extended.

  In this push-in operation, as can be seen by comparing FIG. 7 and FIG. 10, the friction stir welding apparatus M has a higher surface pressure at the slider end than the comparative example. This is because the moment acts as an internal force due to the imbalance of the load on the rolling elements 25 by disposing the respective center positions of the two sliders 22 in the Y-axis direction. However, since the offset shaft 3 is stopped during the pushing operation, even if the surface pressure at the end of the slider increases, the life does not decrease from the viewpoint of the rolling life.

  8 and 11, an offset load Fy in the direction opposite to the offset direction (traveling direction) acts on the welding tool 1, so that the yawing moment My due to the offset load Fy is applied to the slider 22. Works. Here, the yawing moment My is a moment for rotating the sliders 22 around the center PH of the linear guide bearing 11B. It can be seen that the surface pressure at the end of the slider is lower in the friction stir welding apparatus in FIG. 9 than in the comparative example in FIG. 11 under the conditions in which such a yawing moment My acts.

  In the upper slider 22 in the figure, the rolling element 25 on the left side in the figure has a higher surface pressure than the rolling element 25 on the right side, and the lower slider 25 in the figure is on the right side in the figure. The rolling element 25 has a higher surface pressure than the rolling element 25 on the left side in the figure. However, by shifting the center position of the slider 22, the number of rolling elements 25 on the higher surface pressure side is increased. This is because the load supported by the moving body 25 is reduced. It can be seen that the surface pressure of the slider 22 is reduced by reducing the load of the rolling elements 25 per one.

  The relationship between the above surface pressures is shown in FIG. 12 and FIG. 13 as a modified example when the bracket 48 is fixed to the table 23 of the offset shaft 3 without making an inclination angle, that is, the center axis Q of the welding tool 1 is added. The same applies to the case where the pressure shaft 2 is arranged in parallel to the axis.

  As described above, according to the friction stir welding apparatus M incorporating the linear motion guide bearing 11B of the present embodiment, the pair of sliders 22 sandwiching the guide rail 20 of the linear motion guide bearing 11B are positioned relative to each other in the Y-axis direction. Since they are shifted, the surface pressure acting on the rolling elements 25 at the end of the slider 22 can be suppressed even when the yawing moment My acts on the table 23. For example, in the friction stir welding apparatus M, the linear motion guide bearing 11B is used as the linear guide means of the offset shaft 3, and therefore, due to the yawing moment My of the linear motion guide bearing 11B during the offset operation of the friction stir welding M. Therefore, the surface pressure at the end of the slider can be reduced, and the life of the linear motion guide bearing 11B can be extended. Therefore, the yawing moment resistance in one direction can be improved without extending the lengths of the sliders 22 separated from each other, which can contribute to the compactness of the friction stir welding apparatus M.

  Further, since the ball screw integrated linear motion guide unit 10A, in which the linear motion guide bearing 11A and the ball screw 12A are integrated, is used for the pressure shaft 2 that moves the welding tool 1 in the axial direction thereof, the compactness of the apparatus is achieved. And simplification can be further achieved.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, in the above-described embodiment, the guide rail 20 is configured such that the rail blocks 21 are attached to both sides of the base member 20A. However, the base member 20A and the rail block 21 may be integrally processed to form a guide rail. Moreover, in the said embodiment, although the guide rail 20 is made into the structure which attached a pair of rail block 21 to the both sides of the base member 20A, even if it makes a pair of rail block 21 into one rail block and makes both sides into a rolling surface Good.

  In the above-described embodiment, the guide rail 20 is fixed in the Y-axis direction and the table 23 to which the slider 22 is fixed is movable in the Y-axis direction. That is, the slider 22 side may be a fixed side and the guide rail 20 side may move.

  Further, in the above embodiment, the case where the ball screw integrated linear motion guide unit 10A in which the ball screw nut 17 and the slider 14 are integrated is adopted as the pressure shaft 2, but the ball screw nut 17 and the slider 14 are used. The linear motion guide bearing 11A and the ball screw 12A may be combined as separate mechanisms.

  Moreover, in the said embodiment, although the rolling element 25 of the linear motion guide bearing 11B was comprised with the ball | bowl, it is good also as a roller and the non-circulation type linear motion which does not have the mechanism which circulates the linear motion guide bearing 11B through the rolling element 25 is sufficient. It may be a guide bearing. Further, an outer raceway groove having a right isosceles triangular cross section composed of a first inclined track surface and a second tilted track surface orthogonal to each other is provided on the outer peripheral surface of the rail block 21, and the inner peripheral surface of the slider 22 is mutually connected. A plurality of first rollers are provided which are provided with inner raceway grooves each having a right isosceles triangular cross section composed of a third inclined raceway surface and a fourth inclined raceway surface which are orthogonal to each other and are brought into rolling contact with the first and fourth inclined raceway surfaces, respectively. And the same number of second rollers as the first rollers that are located between the adjacent first rollers and that are in rolling contact with the second and third inclined raceway surfaces. It is good.

M Friction stir welding device PA, PB A line parallel to the X-axis direction passing through the center in the Y-axis direction of the slider PH Center of the linear motion guide bearing 1 Joining tool 2 Pressurizing shaft 3 Offset shaft 4 Swivel shaft 10A Ball screw integrated type straight Motion guide unit (pressure axis, X axis)
11A, 11B Linear motion guide bearing 12A Ball screw 12B Ball screw unit 13 Guide rail 13A Sleeve portion 14 Slider 15 Rolling element 16C Rolling passageway 16A, 16B Rolling surface 17 Ball screw nut 18 Ball screw shaft 19 Ball 20 Guide rail 22 Slider 23 Table 25 Rolling element 26A, 26B Rolling surface 42 Pressure shaft motor 43 Offset shaft motor 44 Rotating shaft motor 48 Rotating shaft bracket 49 Tapered give

Claims (4)

At least one guide rail extending in a straight line, a pair of sliders sandwiching the guide rail, and a rolling surface formed on the guide rail and the opposing surfaces of the sliders, the sliders and the guides. A plurality of rolling elements that enable relative movement with the rail, and a table to which the pair of sliders are fixed together,
The linear motion guide bearing, wherein the pair of sliders are fixed to the table by shifting respective center positions in the guide direction by the guide rails in the guide direction. End caps are attached to both ends of the slider in the guiding direction,
A rolling path is formed between the rolling surface of the guide rail and the rolling surface of each slider so that the rolling element moves while rolling,
The slider and the end cap form a rolling path of the rolling element including the rolling path as a part of the path,
The linear motion guide bearing according to claim 1, wherein the rolling elements are accommodated so as to circulate through the circulation path. By rotating the welding tool while pressing it against the workpiece, frictional heat is generated at the contact point between the welding tool and the workpiece to soften and agitate the material around the contact point, whereby the welding tool is applied to the workpiece. It is a friction stir welding apparatus that joins the workpieces linearly by moving the joining tool in the direction of the surface of the workpieces after immersion.
A pivot for rotating the welding tool about its axis;
A pressure shaft for approaching / separating the joining tool from the workpiece;
An offset shaft that moves the joining tool in the surface direction of the workpiece, which is a direction orthogonal to the axis of the pressing shaft, and
The linear motion guide bearing according to claim 1 or 2 is used as the linear guide means of the offset shaft,
The fixed side member of the linear guide means of the pressure shaft is fixed to the base, and the guide rail of the linear guide bearing is fixed on the movable side member of the linear guide means of the pressure shaft,
The friction stir welding apparatus, wherein the pivot shaft is disposed on a table of the linear motion guide bearing. As the linear guide means and linear drive means of the pressure shaft,
The guide rail as the fixed side member having a substantially U-shaped cross section, the slider as the movable side member disposed in the U-shaped recess of the guide rail, the guide rail, and the slider A plurality of rolling elements disposed therebetween, wherein the guide rail has a rolling surface on an inner surface of each sleeve portion opposed to the slider, and the slider has the rolling surface of the guide rail. A rolling surface disposed opposite to the moving surface, and the rolling element is interposed between the rolling surface of the guide rail and the rolling surface of the slider, whereby the slider, the guide rail, A linear motion guide bearing that is relatively movable,
A ball screw nut formed in parallel with the guide rail, a ball screw shaft penetrating the ball screw nut, and a plurality of screws disposed between the spiral groove of the ball screw nut and the spiral groove of the ball screw shaft. A ball screw comprising a ball, and
The friction stir welding apparatus according to claim 3, wherein a ball screw integrated linear motion guide unit including the ball screw nut in the slider is used.

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