Workpiece holding device and workpiece conveyance device

1 . A workpiece holding device comprising:

a plurality of first claw portions disposed to hold a workpiece in a center of the plurality of first claw portions, and disposed to be spaced apart from each other in a predetermined plane, the plurality of first claw portions disposed to move linearly in a direction parallel to the predetermined plane;

a second claw portion and a third claw portion disposed to hold the workpiece therebetween, and to face each other in a direction orthogonal to the predetermined plane; and

a motion conversion mechanism portion that converts a linear motion associated with movement of the first claw portion into a linear motion in the direction orthogonal to the predetermined plane, transmits the linear motion to the second claw portion, and causes the second claw portion to linearly move in the direction orthogonal to the predetermined plane,

each one of the plurality of first claw portions having a first grasping surface,

the second claw portion having a second grasping surface,

the third claw portion having a third grasping surface,

the first grasping surface being different in shape from the second and third grasping surfaces.

2 . The workpiece holding device according to claim 1 , wherein the second claw portion and the third claw portion are provided in positions deviated from the plurality of first claw portions in the direction orthogonal to the predetermined plane.

3 . The workpiece holding device according to claim 1 , wherein the second claw portion and the third claw portion are provided in positions surrounded by the plurality of first claw portions when viewed in the direction orthogonal to the predetermined plane.

4 . A workpiece holding device comprising:

a plurality of first claw portions disposed to hold a workpiece in a center of the plurality of first claw portions, and disposed to be spaced apart from each other in a predetermined plane, the plurality of first claw portions disposed to move linearly in a direction parallel to the predetermined plane;

a second claw portion and a third claw portion disposed to the workpiece therebetween, and to face each other in a direction orthogonal to the predetermined plane; and

a motion conversion mechanism portion that converts a linear motion associated with movement of the first claw portion into a linear motion in the direction orthogonal to the predetermined plane, transmits the linear motion to the second claw portion, and causes the second claw portion to linearly move in the direction orthogonal to the predetermined plane,

the third claw portion being integrated with the first claw portion.

5 . The workpiece holding device according to claim 4 , wherein the second claw portion and the third claw portion are provided in positions deviated from the plurality of first claw portions in the direction orthogonal to the predetermined plane.

6 . The workpiece holding device according to claim 4 , wherein the second claw portion and the third claw portion are provided in positions surrounded by the plurality of first claw portions when viewed in the direction orthogonal to the predetermined plane.

7 . A workpiece holding device comprising:

a plurality of first claw portions disposed to hold a workpiece in a center of the plurality of first claw portions, and disposed to be spaced apart from each other in a predetermined plane, the plurality of first claw portions disposed to move linearly in a direction parallel to the predetermined plane;

a second claw portion and a third claw portion disposed to hold the workpiece therebetween, and to face each other in a direction orthogonal to the predetermined plane; and

a motion conversion mechanism portion that converts a linear motion associated with movement of the first claw portion into a linear motion in the direction orthogonal to the predetermined plane, transmits the linear motion to the second claw portion, and causes the second claw portion to linearly move in the direction orthogonal to the predetermined plane,

wherein

the motion conversion mechanism portion includes:

a movement member that has a first inclined surface extending in a diagonal direction relative to the predetermined plane, that is linearly movable in the direction parallel to the predetermined plane together with the first claw portion, and that is supported to be linearly movable in the direction orthogonal to the predetermined plane; and

a fixed member having a second inclined surface that is in surface contact with the first inclined surface, and

the second claw portion is provided in the movement member at a position away from the first inclined surface in the direction orthogonal to the predetermined plane.

8 . The workpiece holding device according to claim 7 , wherein

the plurality of first claw portions are disposed to be spaced apart from each other in a circumferential direction around a predetermined axis orthogonal to the predetermined plane and are linearly movable in a radial direction relative to the predetermined axis, and

the workpiece holding device comprises a unit member in which the first claw portion, the third claw portion, and a supporting portion that supports the movement member to allow the movement member to linearly move in the direction orthogonal to the predetermined plane are integrally provided.

9 . The workpiece holding device according to claim 7 , wherein

the movement member further has a third inclined surface that faces an opposite direction to the first inclined surface, and

the fixed member further has a fourth inclined surface that faces an opposite direction to the second inclined surface and that is in surface contact with the third inclined surface.

10 . A workpiece conveyance device comprising the workpiece holding device according to claim 1 to convey a workpiece held by the workpiece holding device.

11 . A workpiece conveyance device comprising the workpiece holding device according to claim 4 to convey a workpiece held by the workpiece holding device.

12 . A workpiece conveyance device comprising the workpiece holding device according to claim 7 to convey a workpiece held by the workpiece holding device.