JP4714045B2 - Work support device - Google Patents

Description

  The present invention relates to a workpiece support device including an original position return mechanism for returning a workpiece support from a support position to an original position.

  For example, a workpiece such as an automobile part is subjected to processing while being positioned and supported by one or a plurality of workpiece support devices. In order to support the workpiece in a stable state by the workpiece support device, the workpiece support device is moved to a position suitable for supporting the workpiece. After the workpiece machining is completed, the workpiece support device is once returned to the position before movement (original position), and then again to a position suitable for supporting the workpiece to be used for the next machining. It has been moved.

  An example of the workpiece support device configured so that the workpiece support device can be returned to the original position is a workpiece conveyance support device disclosed in Patent Document 1. The workpiece conveyance support device disclosed in Patent Document 1 includes a pair of support portions that support two positions with respect to a workpiece on a carriage that conveys and supports the workpiece. One support part of the pair of support parts is fixed on the carriage. Moreover, on the linear guide rail extended in the length direction of a trolley | bogie, the moving body which can move along this linear guide rail is provided, and the other support part is provided in this moving body.

  The moving body is connected to an external driving mechanism by a connecting portion, and the moving body is moved along the linear guide rail by the external driving mechanism. The external drive mechanism includes a drive unit that moves the connecting portion along the extending direction of the linear guide rail. This drive unit has a screw rod extending parallel to the linear guide rail. A ball guide nut is coupled to the screw rod, and the connecting portion is provided on the ball guide nut. In addition, the screw rod is rotated by a motor, and by driving the motor (NC drive), the ball guide nut, that is, the connecting portion can be moved to a designated position on the screw rod. It can be done.

  And in the workpiece conveyance support apparatus disclosed in Patent Document 1, by driving and controlling the motor, the screw rod rotates and the ball guide nut moves along the screw rod. As the ball guide nut moves, the connecting portion also moves, and the other support portion connected to the ball guide nut via the connecting portion also moves along the linear guide rail. The other support portion is disposed at a position suitable for supporting the workpiece, and the workpiece is supported in a stable state by the pair of support portions and is used for processing. After the workpiece is processed, the moving body is moved by the movement of the ball guide nut by motor drive control in the same manner as described above, and the other support portion is returned to the original position.

As a mechanism for returning the workpiece support device to the original position, there is a mechanism using a spring in addition to Patent Document 1. In the return mechanism using the spring, the spring is connected to the work support device, and the spring is compressed as the work support device moves toward the position for supporting the work. Further, in the return mechanism using the spring, the work support device is moved to a position suitable for supporting the work and is prevented from moving to the original position by the reaction force of the compressed spring. A locking device is provided for locking. After the processing of the workpiece is completed, when the lock device is unlocked, the workpiece support device is pressed by the reaction force of the compressed spring, and the workpiece support device is returned to the original position. Yes.
Japanese Patent Laid-Open No. 2004-154917

  However, in the work conveyance support device disclosed in Patent Document 1, the mechanism for returning the other support portion to the original position includes a motor for rotating the screw rod in addition to the screw rod and the ball guide nut. Is large. Further, in a mechanism that uses a spring to return the workpiece support device to the original position, the spring force of the spring is proportional to the amount of expansion and contraction, so that the amount of movement of the workpiece support device is small and the spring compression amount is small. Although the force (reaction force) is small, the amount of movement of the work support device increases, and the spring force (reaction force) increases as the amount of compression of the spring increases. For this reason, when the movement amount of the work support device is small, the force with which the work support device is pressed by the spring is small, but when the movement amount of the work support device is large, the force with which the work support device is pressed by the spring is small. It becomes larger and it becomes easy to move to the original position. Therefore, the force for locking the work support device by the lock device must be changed according to the amount of movement of the work support device, and when the work support device has a large amount of movement, the work support device is locked. There was a risk of instability.

  An object of the present invention is to provide a work support device that can lock a work support in a stable state at a support position with a constant force while reducing a mechanism for returning the work support to an original position.

  In order to solve the above problem, the invention described in claim 1 includes a linear guide rail extending linearly and a support portion for supporting the workpiece, and the workpiece by the support portion from the original position on the linear guide rail. A workpiece support that moves along the linear guide rail to the support position, a lock device that locks the workpiece support that has moved from the original position to the support position on the linear guide rail, and the workpiece support that supports the workpiece An original position return mechanism for returning from the position to the original position. The original position return mechanism is connected to the shaft-shaped shaft member and the workpiece support, and the shaft is disposed on the outer peripheral side of the shaft member. A magnetic spring having a movable member mounted so as to be relatively movable with respect to the member, and a magnet magnetized with different magnetic poles disposed oppositely between the movable member and the shaft member The movable member moves along the shaft member in conjunction with the movement of the workpiece support from the original position to the support position, while the workpiece support is moved by the attractive force between the magnets. The gist is that the support position is returned to the original position.

  According to a second aspect of the present invention, in the workpiece support device according to the first aspect, a plurality of movable members are mounted on the outer peripheral side of the shaft member in a radial direction of the shaft member, and the radial direction The gist is that magnets magnetized with different magnetic poles are arranged opposite to each other between the movable members facing each other.

  According to a third aspect of the present invention, in the workpiece support device according to the second aspect, the plurality of movable members include a first movable member mounted on an outer peripheral side of the shaft member, and an outer periphery of the first movable member. The gist is that the second movable member is mounted on the side.

  According to a fourth aspect of the present invention, in the workpiece support device according to any one of the first to third aspects, the shaft member and the linear guide rail include an axial direction of the shaft member and a linear guide. It is arranged that the length direction of the rail is parallel to each other, and the movable member moves in the same direction as the movement direction of the workpiece support.

  The invention according to claim 5 is the work support device according to any one of claims 1 to 4, wherein the movable member is fixed to the support portion of the work support, The gist is that the workpiece support and the in-situ return mechanism are connected by the support portion.

  The gist of the invention according to claim 6 is the work support device according to any one of claims 1 to 5, wherein the original position is an axial center of the shaft member.

  ADVANTAGE OF THE INVENTION According to this invention, a workpiece | work support body can be locked in the stable state in a support position with fixed force, making the mechanism which returns a workpiece | work support body to an original position compact.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which a workpiece support device of the present invention is embodied as a workpiece support device that positions and supports a workpiece when processing a workpiece (automobile part) will be described with reference to FIGS. In the following description, “front” and “rear” of the workpiece support device are the directions of the arrow Y1 shown in FIG. 1, and “upper” and “lower” are the directions of the arrow Y2 shown in FIG. And

  As shown in FIGS. 1 and 2, work support devices 10 are installed at the four corners of a rectangular carriage-like carriage P, and the carriage P is movable in the front-rear direction indicated by the arrow Y1. Has been. Further, the workpiece W is positioned and supported by the four workpiece support devices 10 on the transport carriage P.

  When processing the workpiece W, first, the transport carriage P is moved to the workpiece input position, and the workpiece support device 10 is moved to a predetermined position (moving step). Thereafter, the workpiece W is loaded (a loading step), and the workpiece W is positioned and supported by the workpiece support device 10 (a supporting step). Furthermore, the transport carriage P is moved to the work position while the work support device 10 supports the work W, and the work W is transported to the work position (transport process). Thereafter, the work of the work W such as a welding work is performed at the work position (work process). In addition, after the work process is finished, the processed workpiece W is removed from the transport carriage P, and the transport carriage P and the work support device 10 are returned to the positions before the movement (return process).

  Next, the workpiece support device 10 will be described. As shown in FIGS. 3A and 3B, the work support device 10 has a base B having an elongated rectangular plate shape, and the base B extends in the longitudinal direction of the transport carriage P. In this way, it is fixed on each corner of the transport carriage P. On the base B, a linear guide rail 11 that extends linearly along the length direction of the base B is fixed. A linear guide block 12 is mounted and supported on the linear guide rail 11, and the linear guide block 12 can be moved in the front-rear direction along the linear guide rail 11 by a driving force of an external driving source (not shown). It has become.

  Further, a table 13 as a support part for supporting the workpiece W is fixed to the upper surface of the linear guide block 12, and the table 13 has a thick plate shape, and positioning pins 14 are directed upward on the upper surface 13a. Projected toward. The positioning pin 14 is inserted into a reference hole (not shown) provided in the workpiece W. Then, the positioning pin 14 is inserted into the reference hole, and the workpiece W is supported on the upper surface 13 a of the table 13, whereby the workpiece W is positioned and supported on the table 13.

  In the present embodiment, a workpiece support T that supports the workpiece W is constituted by the linear guide block 12 and the table 13 fixed to the linear guide block 12. During the movement process, the workpiece support T is positioned so that the positioning pin 14 matches the reference hole of the workpiece W and can support the workpiece W in a stable state (support position) by the driving force of the external drive source. ) (See FIGS. 1 and 2).

  In the workpiece support device 10, a locking device 15 is attached to the linear guide rail 11, and the locking device 15 is connected and fixed to the table 13 by a fixing member 24. For this reason, the workpiece support T is integrally provided with a locking device 15, and the locking device 15 moves integrally on the linear guide rail 11 as the workpiece support T moves. The lock device 15 has an air supply / discharge port 15a. The lock device 15 can be locked onto the linear guide rail 11 by supplying air to the air supply / discharge port 15a, while the lock device 15 is discharged by discharging air from the air supply / discharge port 15a. Can be unlocked. That is, since the workpiece support T is integrally provided with the lock device 15, the workpiece support T can be locked onto the linear guide block 12 by the lock by the lock device 15, and the workpiece can be released by the lock device 15 being unlocked. The lock of the support T on the linear guide rail 11 can be released.

  In the work support device 10, an original position return mechanism H is provided on the base B to return the work support T (linear guide block 12) from the movement destination (support position) to the position before movement (original position). It has been. Next, the original position return mechanism H will be described.

  First, on the base B, a pair of mounting members 16 facing the length direction of the base B are fixed, and each end of the shaft member 17 is fixedly mounted on the pair of mounting members 16 (FIG. 5). And FIG. 6). The shaft member 17 is disposed on the base B so that the axial direction thereof is parallel to the extending direction (length direction) of the linear guide rail 11. As shown in FIGS. 4 and 5, a cylindrical exterior member 18 is mounted on the peripheral surface of the shaft member 17, and a magnet (permanent magnet) is provided at the center in the length direction of the exterior member 18. ) 19 is bonded and fixed.

  Further, a cylindrical first movable member 21 is mounted on the outer peripheral side of the exterior member 18, and the first movable member 21 is opposed to the shaft member 17 (the exterior member 18). It is provided so that relative movement is possible along the axial direction. A magnet (permanent magnet) 20 as a magnet is bonded and fixed to the outer peripheral surface of the first movable member 21 so as to face the magnet 19. The exterior member 18 (magnet 19) and the first movable member 21 are arranged with a slight gap (not shown) in the radial direction of the shaft member 17.

  The magnet 19 of the shaft member 17 and the magnet 20 of the first movable member 21 are formed so that the lengths in the axial direction are the same length. The magnet 19 is divided into two in the circumferential direction of the exterior member 18 and is configured by arranging an N pole band 19N and an S pole band 19S formed in a band shape with a width of 180 degrees. An N-pole band 20N and an S-pole band 20S that are divided into two in the circumferential direction of the movable member 21 and are formed in a band shape with a width of 180 degrees are arranged. The magnet 19 and the magnet 20 are configured by arranging different magnetic poles to face each other.

  The first movable member 21 is movable along the shaft member 17 by the length of the magnet 20. Further, the magnet 19 and the magnet 20 generate a magnetic force that acts so as to attract the relative displacement between the shaft member 17 and the first movable member 21, thereby exerting the spring function. This spring function is exerted by an attractive force that attempts to pull back the moved magnet 20 with respect to the fixed magnet 19 when the first movable member 21 moves along the shaft member 17.

  A second movable member 22 having a rectangular tube shape is mounted on the outer peripheral side of the first movable member 21, and the second movable member 22 is fixed to the lower surface of the table 13. A plurality (two in this embodiment) of movable members 21 and 22 are attached to the shaft member 17 so as to overlap along the radial direction of the shaft member 17. The second movable member 22 is provided to be movable relative to the shaft member 17 (exterior member 18) and the first movable member 21. A magnet (permanent magnet) 23 as a magnet is bonded and fixed to the inner peripheral surface of the second movable member 22 so as to face the magnet 20. The magnet 20 of the first movable member 21 and the magnet 23 of the second movable member 22 are arranged with a slight gap (not shown) in the radial direction of the shaft member 17.

  The magnet 20 of the first movable member 21 and the magnet 23 of the second movable member 22 are formed to have the same length in the axial direction. Further, the magnet 20 is configured by arranging the above-described N-pole band 20N and S-pole band 20S, and the magnet 23 is divided into two in the circumferential direction of the second movable member 22 and is formed in a band shape with a width of 180 degrees. The N pole band 23N and the S pole band 23S are arranged. The magnet 20 and the magnet 23 are configured by alternately disposing different magnetic poles.

  The second movable member 22 is movable along the first movable member 21 by the length of the magnet 23. Further, the magnet 20 and the magnet 23 generate a magnetic force that acts so as to attract the relative displacement between the first movable member 21 and the second movable member 22, thereby exhibiting a spring function. This spring function is exhibited by an attractive force that attempts to pull back the moved magnet 23 relative to the fixed magnet 20 when the second movable member 22 moves along the first movable member 21.

  Then, as shown in FIG. 5, the original position return mechanism H in the workpiece support device 10 is constituted by the shaft member 17 (magnet 19), the first movable member 21 (magnet 20), and the second movable member 22 (magnet 23). Is configured. Further, the magnet 19 in the shaft member 17, the magnet 20 in the first movable member 21, the magnet 20 in the first movable member 21, and the magnet 23 in the second movable member 22, the original position return mechanism H has a magnetic spring mechanism. Is configured. In the original position return mechanism H, the magnet 19 of the shaft member 17 and the magnet 20 of the first movable member 21 are magnetized, and further, the magnet 20 of the first movable member 21 and the magnet 23 of the second movable member 22 are magnetized. In the magnetized state, the table 13 is positioned at the axial center of the shaft member 17. Thus, when the table 13 is located at the center of the shaft member 17 in the axial direction, the workpiece support T is the original in the workpiece support device 10 as shown in the two-dot chain line of FIGS. Located in position. The workpiece support T is movable from the original position to the support position as shown by the solid lines in FIGS. 1 and 2 by the driving force of the external drive source.

  Next, the operation of the workpiece support device 10 having the above configuration will be described. When processing the workpiece W, first, in the moving process, the transport carriage P is moved, and as shown by the solid lines in FIGS. 1 and 2, the positioning pins of the workpiece support devices 10 are inserted into the reference holes of the workpiece W. The workpiece support T (linear guide block 12) is moved to the support position along the linear guide rail 11 so that 14 matches. At this time, as indicated by a two-dot chain line in FIG. 5, the second movable member 22 moves in the backward direction (the direction from left to right in FIG. 1) as the work support T moves. The magnet 23 provided on the second movable member 22 moves in the same direction together with the second movable member 22. When the second movable member 22 moves, an attractive force that pulls back the moved magnet 23 relative to the magnet 20 fixed in position between the magnet 20 of the first movable member 21 and the magnet 23 of the second movable member 22. Is working.

  Further, as shown in FIG. 6, the first movable member 21 moves in the backward direction (in the direction from left to right in FIG. 1) as the second movable member 22 moves. At this time, the magnet 20 provided on the first movable member 21 moves in the same direction together with the first movable member 21. When the first movable member 21 moves, an attractive force is exerted between the magnet 20 of the first movable member 21 and the magnet 19 of the shaft member 17 to pull back the moved magnet 20 with respect to the magnet 19 fixed in position. ing.

  The suction force generated in the original position return mechanism H shows a constant value regardless of the movement amounts of the first movable member 21 and the second movable member 22. That is, in the magnetic spring mechanism, when the magnet 20 and the magnet 23 and the magnet 19 and the magnet 20 are displaced in the axial direction, the magnetic force lines generated obliquely at the end portions of the magnets 19 and 20 and the magnets 20 and 23 are axial. A certain thrust is generated by the component force. That is, when the magnets 19 and 20 and the magnets 20 and 23 are shifted and overlapped, an oblique line of magnetic force is generated in a certain direction (constant inclination) at the ends of the magnets 19 and 20 and the magnets 20 and 23. In the overlapping portion between them, magnetic field lines only in the vertical direction that do not affect the axial force are generated. For this reason, the axial force acts on the magnets 19 and 20 and the magnets 20 and 23 only by the axial component of the oblique lines of magnetic force generated at the ends regardless of the overlapping width. Therefore, in the original position return mechanism H, a constant suction force is always generated between the magnet 19 and the magnet 20 and between the magnet 20 and the magnet 23, and the workpiece support T is always a constant suction. It is pulled to the original position by force.

  1 and FIG. 2, after the workpiece support T has moved to the support position, the linear guide block 12 is locked to the linear guide rail 11 by the lock device 15, and the workpiece support T is supported at the support position. Lock to. Thereafter, a charging process, a transport process, and a work process are performed.

  When the work W is removed after the work process is finished, the lock by the lock device 15 is released. Then, the second movable member 22 is pulled back to the first movable member 21 by the attractive force acting between the magnet 20 of the first movable member 21 and the magnet 23 of the second movable member 22. Further, the first movable member 21 is pulled back to the axial center of the shaft member 17 by the attractive force acting between the magnet 20 of the first movable member 21 and the magnet 19 of the shaft member 17. As a result, as shown by the two-dot chain line in FIGS. 1 and 2, the workpiece support T is automatically returned to the original position.

According to the above embodiment, the following effects can be obtained.
(1) In the workpiece support device 10, the original position return mechanism H that returns the workpiece support T moved to the support position to the original position is provided with a magnetic spring mechanism, and the workpiece is generated by the attractive force generated by the magnetic spring mechanism. The support T is returned from the support position to the original position. The original position return mechanism H is configured by mounting the first movable member 21 and the second movable member 22 on the shaft member 17, and the shaft member 17, the first movable member 21, and the second movable member 22. The workpiece support T can be returned to the original position by the attraction force of the magnets 19, 20, and 23 provided on. That is, the physique of the original position return mechanism H is formed by only the shaft member 17, the first movable member 21, and the second movable member 22, and does not require an external drive source such as a motor. The physique of H can be made compact.

  (2) Further, the original position return mechanism H generates an attractive force in the same manner as the coil spring by the action of the magnet 19 and the magnet 20 constituting the magnetic spring mechanism and the action of the magnet 20 and the magnet 23, and the attractive force. Are constant values regardless of the amount of movement of the first movable member 21 and the amount of movement of the second movable member 22. That is, since the suction force is constant, the force required to lock the workpiece support T by the lock device 15 is constant even if the movement amount of the first movable member 21 and the second movable member 22 varies. It's okay. As a result, as the coil spring is compressed as the workpiece support T is moved, for example, when the coil spring is used as the original position return mechanism H, the force that locks the workpiece support T is increased. The workpiece support T can be locked at the support position in a stable state with a constant force without requiring a large amount.

  (3) The shaft member 17 is disposed so as to be parallel to the linear guide rail 11, and the first movable member 21 and the second movable member 22 move in the same direction as the movement direction of the workpiece support T. For this reason, for example, the shaft member 17 is arranged so as to be orthogonal to the linear guide rail 11 and the workpiece support T and the original position return mechanism H are connected via a link mechanism or the like. The physique of the position return mechanism H can be made compact, and the workpiece support T can be returned quickly and accurately.

  (4) In the original position return mechanism H, the first movable member 21 and the second movable member 22 are mounted on the shaft member 17 in an overlapping manner, and the first movable member 21 is moved relative to the shaft member 17, and By moving the second movable member 22 relative to the first movable member 21, the movable distance of the workpiece support T can be increased. For this reason, for example, when the distance by which the workpiece support T can be moved by overlapping the first movable member 21 and the second movable member 22 can be moved by one movable member, A dimension becomes long and the original position return mechanism H will enlarge. On the other hand, by overlapping the first movable member 21 and the second movable member 22, the length of the magnet in the axial direction can be shortened, and the original position return mechanism H can be made compact. .

  (5) The second movable member 22 in the original position return mechanism H is fixed to the table 13 in the workpiece support T. That is, the original position return mechanism H and the workpiece support T are connected by the table 13 that supports the workpiece W. For this reason, for example, compared with the case where the original position return mechanism H and the workpiece support T are connected not by the table 13 but by another connecting member, the number of members of the workpiece support device 10 is reduced, and the workpiece support device 10 It can contribute by downsizing and can reduce the manufacturing cost.

  (6) The original position of the workpiece support T is a position where the second movable member 22 in the original position return mechanism H is disposed at the axial center of the shaft member 17. For this reason, the first movable member 21 and the second movable member 22 can move equidistantly both forward and backward along the axial direction of the shaft member 17. Therefore, the movable range of the workpiece support T can be maximized, the workpiece W can be supported at a more appropriate position by the workpiece support device 10, and the workpiece W can be processed in a more stable state. Is possible. Even when the workpiece W moves from the original position to the position farthest away in the front-rear direction, the return time to the original position can be minimized.

In addition, you may change the said embodiment as follows.
The second movable member 22 in the original position return mechanism H and the work support T may be connected by a connecting member different from the table 13. For example, the locking device 15 connected to the workpiece support T and the second movable member 22 may be connected by a connecting member.

  A configuration in which the original position return mechanism H is constituted by the shaft member 17 (magnet 19) and the first movable member 21 (magnet 20) mounted on the outer periphery of the shaft member 17, and the second movable member 22 is omitted. In this case, the table 13 of the workpiece support T is fixed to the first movable member 21.

  In the original position return mechanism H, a third movable member provided with a magnet that magnetizes the magnet 23 of the second movable member 22 is mounted on the outer periphery of the second movable member 22, and a workpiece support is attached to the third movable member. The T table 13 may be fixed.

In the original position return mechanism H, the number of movable members attached to the shaft member 17 may be arbitrarily changed according to the length of the shaft member 17 in the axial direction.
In the original position return mechanism H, the lengths of the magnets 19, 20, 23 in the axial direction may be changed.

  ○ The shaft member 17 is arranged so as to extend in a direction orthogonal to the direction in which the linear guide rail 11 extends, and the second movable member 22 of the original position return mechanism H and the work support T are connected via a link mechanism. Thus, the workpiece support device 10 may be configured.

The locking device 15 may be integrally formed with the work support T.
O It is good also as the workpiece support T which integrally formed the table 13 in the linear guide block 12.

A side view showing arrangement of a work support device of an embodiment. The top view which shows the state which supported the workpiece | work with the workpiece | work support apparatus of embodiment. (A) is a top view which shows a workpiece | work support apparatus, (b) is a side view which shows a workpiece | work support apparatus. FIG. 4B is a sectional view taken along line 4-4 in FIG. FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. Sectional drawing which shows operation | movement of a workpiece | work support apparatus.

Explanation of symbols

  H ... Original position return mechanism, T ... Work support, W ... Work, 10 ... Work support device, 11 ... Linear guide rail, 13 ... Table constituting support part, 15 ... Lock device, 17 ... Shaft member, 19, 20, 23 ... Magnets as magnets constituting the magnetic spring mechanism, 21 ... first movable member, 22 ... second movable member.

Claims (6)

A linear guide rail extending linearly;
A work support that moves along the linear guide rail from an original position on the linear guide rail to a work support position by the support;
A locking device that locks the workpiece support moved from the original position to the support position on the linear guide rail;
An original position return mechanism for returning the workpiece support from the support position to the original position;
The original position return mechanism includes a shaft-shaped shaft member and a movable member that is connected to the workpiece support and is mounted on the outer peripheral side of the shaft member so as to be movable relative to the shaft member. The movable member and the shaft member are composed of a magnetic spring mechanism in which magnets magnetized with different magnetic poles are arranged opposite to each other, and interlocked with the movement of the workpiece support from the original position to the support position. Then, while the movable member moves along the shaft member, the workpiece support is returned from the support position to the original position by the attractive force of the magnets. On the outer peripheral side of the shaft member, a plurality of movable members are mounted in the radial direction of the shaft member, and magnets magnetized with different magnetic poles are opposed to the movable members facing in the radial direction. The workpiece support device according to claim 1. The plurality of movable members include a first movable member mounted on the outer peripheral side of the shaft member and a second movable member mounted on the outer peripheral side of the first movable member. Work support device. The shaft member and the linear guide rail are arranged such that the axial direction of the shaft member and the length direction of the linear guide rail are parallel to each other, and the movable member is in the same direction as the moving direction of the workpiece support The workpiece support device according to any one of claims 1 to 3, which moves to a position. The said movable member is being fixed to the said support part of the said work support body, The work support body and the original position return mechanism are connected by this support part. The workpiece support device described in 1. The workpiece support device according to any one of claims 1 to 5, wherein the original position is an axial center of the shaft member.

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