Method for adjusting the tension of industrial robots and belts

Abstract

This invention provides a method for adjusting the tension of two belts. [Solution] In this industrial robot, the second pulley 46 positioned at the joint 33 of the parallel link arm comprises an upper pulley 50 to which the end of the first belt 47 is fixed, and a lower pulley 51 to which the end of the second belt 48 is fixed. The upper pulley 50 and the lower pulley 51 have positioning portions 50b and 51b formed therein for positioning the lower pulley 51 relative to the upper pulley 50 in the radial direction of the upper pulley 50 and the lower pulley 51. The lower pulley 51 has a first hole 51d that penetrates the lower pulley 51 in the vertical direction, and the first hole 51d is formed in the shape of an elongated hole with its longitudinal direction inclined with respect to the direction perpendicular to the radial direction and vertical direction of the lower pulley 51. The upper pulley 50 has a round second hole 50d that overlaps with the first hole 51d in the vertical direction and is connected to the first hole 51d.

Description

Technical Field

[0001] The present invention relates to an industrial robot. The present invention also relates to a belt tension adjustment method.

Background Art

[0002] Conventionally, a transport apparatus for transporting semiconductor wafers is known (see, for example, Patent Document 1). The transport apparatus described in Patent Document 1 includes a thin plate-shaped holding member for holding a semiconductor wafer, an arm to which the holding member is rotatably connected at a distal end portion, and a base to which a proximal end portion of the arm is rotatably connected. The arm is a parallel link arm having two parallel link mechanisms, and is constituted by a pair of a first inner arm and a second inner arm, and a pair of a first outer arm and a second outer arm.

[0003] In the transport apparatus described in Patent Document 1, the proximal end portion of the first inner arm and the proximal end portion of the second inner arm are rotatably connected to the base. A lower end portion of a first connection shaft is fixed to the distal end portion of the first inner arm. The proximal end portion of the first outer arm is rotatably attached to an upper end portion of the first connection shaft. The proximal end portion of the second outer arm is fixed to an upper end portion of a second connection shaft. A distal end portion of the second inner arm is rotatably attached to a lower end portion of the second connection shaft. A first pulley is fixed to the first connection shaft, and a second pulley is fixed to the second connection shaft.

[0004] In the transport apparatus described in Patent Document 1, one end portion of an upper belt and one end portion of a lower belt are fixed to the first pulley, and the other end portion of the upper belt and the other end portion of the lower belt are fixed to the second pulley. The upper belt and the lower belt are attached to the first pulley and the second pulley in a crossed belt arrangement. Therefore, in the transport apparatus described in Patent Document 1, when the first connection shaft and the first pulley rotate clockwise, the second connection shaft and the second pulley rotate counterclockwise via the lower belt. Further, when the first connection shaft and the first pulley rotate counterclockwise, the second connection shaft and the second pulley rotate clockwise via the upper belt.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-38686 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the conveying device described in Patent Document 1, it is necessary to adjust the tension of two belts, an upper belt and a lower belt. However, in this conveying device, the two belts are attached to the first pulley and the second pulley in a crisscross pattern, making it complicated to adjust the tension of the two belts. That is, for example, if the fixing position of the first pulley to the first connecting shaft is changed in the circumferential direction of the first connecting shaft, the tension of one belt will increase, but the tension of the other belt will decrease. Therefore, it is difficult to properly adjust the tension of the two belts by changing the fixing position of the first pulley to the first connecting shaft.

[0007] Similarly, in the conveying device described in Patent Document 1, it is difficult to properly adjust the tension of the two belts by changing the fixing position of the second pulley to the second connecting shaft in the circumferential direction of the second connecting shaft. Therefore, in the conveying device described in Patent Document 1, when adjusting the tension of the two belts, each end of the two belts must be removed from the first or second pulley, resulting in a complicated adjustment of the tension of the two belts.

[0008] Therefore, an object of the present invention is to provide an industrial robot with parallel link arms that allows for easy adjustment of the tension of two belts, even when two belts are attached in a diagonal fashion to a first pulley and a second pulley located at the joint of the parallel link arms. Another object of the present invention is to provide a method for adjusting the tension of two belts in such an industrial robot. [Means for solving the problem]

[0009] To solve the above problems, an industrial robot according to one aspect of the present invention comprises a hand on which an object to be transported is mounted, an arm to which the hand is rotatably connected at its tip, and a main body to which the base end of the arm is rotatably connected, wherein the arm is a parallel link arm having two parallel link mechanisms, comprising a first parallel arm section and a second parallel arm section parallel to each other, and a third parallel arm section and a fourth parallel arm section parallel to each other, wherein the base ends of the first parallel arm section and the base ends of the second parallel arm section are rotatably connected to the main body, and the base end of the third parallel arm section is the tip of the first parallel arm section The end of the fourth parallel arm is rotatably connected, the base end of the fourth parallel arm is rotatably connected to the tip of the second parallel arm, the tip of the third parallel arm and the tip of the fourth parallel arm are rotatably connected to the hands, and the joints that form the connection between the first parallel arm and the third parallel arm and the connection between the second parallel arm and the fourth parallel arm are equipped with a first pivot shaft to which the tip of the first parallel arm is fixed, a second pivot shaft to which the base end of the fourth parallel arm is fixed, a first pulley fixed to the first pivot shaft, a second pulley fixed to the second pivot shaft, and a first belt formed in the shape of a strip. A first and second belt are arranged, the axial direction of the first pivot shaft and the axial direction of the second pivot shaft coincide with the vertical direction, the base end of the third parallel arm is rotatably attached to the first pivot shaft, the tip of the second parallel arm is rotatably attached to the second pivot shaft, one end of the first belt and one end of the second belt are fixed to the first pulley, the other end of the first belt and the other end of the second belt are fixed to the second pulley, the winding direction of the first belt around the first pulley and the winding direction of the second belt around the first pulley are opposite, and the winding direction of the first belt around the second pulley The direction is opposite to the winding direction of the second belt around the second pulley, and the first pulley or second pulley comprises an upper pulley and a lower pulley that overlap in the vertical direction, the end of the first belt is fixed to the upper pulley and the end of the second belt is fixed to the lower pulley, the upper pulley and the lower pulley have positioning parts formed therein for positioning the lower pulley relative to the upper pulley in the radial direction of the upper pulley and the lower pulley, and a first hole is formed in either the upper pulley or the lower pulley that penetrates either the upper pulley or the lower pulley in the vertical direction.The first hole is formed in an elongated shape with its longitudinal direction inclined with respect to the direction perpendicular to the radial and vertical directions of the upper and lower pulleys. A second round hole is formed in either the upper or lower pulley, overlapping the first hole in the vertical direction and connecting to it.

[0010] In this embodiment of the industrial robot, the first or second pulley positioned at the joint of the parallel link arm comprises an upper pulley to which the end of the first belt is fixed and a lower pulley to which the end of the second belt is fixed. The upper and lower pulleys are formed with positioning portions for positioning the lower pulley relative to the upper pulley in the radial direction of the upper and lower pulleys. In this embodiment, a first hole is formed in either the upper or lower pulley, penetrating either the upper or lower pulley in the vertical direction. The first hole is formed in the shape of an elongated hole, with its longitudinal direction inclined with respect to the direction perpendicular to the radial and vertical directions of the upper and lower pulleys. Furthermore, in this embodiment, a second round hole is formed in either the upper or lower pulley, overlapping the first hole in the vertical direction and connecting to the first hole.

[0011] Therefore, in this embodiment, for example, a jig comprising a cylindrical jig body partially positioned in the first hole and a cylindrical pivot axis positioned in the second hole with its axis offset from the axis of the jig body is attached to the upper and lower pulleys, and with the fixing state of the upper and lower pulleys loosened, the jig body is rotated around the pivot axis, thereby rotating the upper and lower pulleys in opposite directions to make it possible to increase or decrease the tension of the first and second belts together. Consequently, in this embodiment, even if two belts are attached to the first and second pulleys in a crisscross pattern, it becomes possible to easily adjust the tension of the two belts.

[0012] In an industrial robot according to this embodiment, in which either the upper pulley or the lower pulley is fixed to the other of the upper pulley or the lower pulley, and the other of the upper pulley or the lower pulley is fixed to the first or second rotation axis, the tension of the first belt and the second belt are adjusted, for example, by the following belt tension adjustment method. In other words, in a belt tension adjustment method for adjusting the tension of the first and second belts, for example, the fixed state of the upper and lower pulleys is loosened, and a jig is attached to the upper and lower pulleys, which has a cylindrical jig body with part of it positioned in the first hole and a cylindrical pivot axis connected to one end face of the jig body and positioned in the second hole, with its axis offset from the axis of the jig body. The jig body is then rotated around the pivot axis to rotate the upper and lower pulleys, thereby adjusting the tension of the first and second belts, and after that, the upper and lower pulleys are fixed in place. By adjusting the tension of the first and second belts using this belt tension adjustment method, it becomes possible to easily adjust the tension of the two belts even if the two belts are attached to the first and second pulleys in a crisscross pattern. [Effects of the Invention]

[0013] As described above, in one aspect of the present invention, in a horizontal articulated industrial robot having parallel link arms, even if two belts are attached in a diagonal fashion to a first pulley and a second pulley located at the joint of the parallel link arms, it becomes possible to easily adjust the tension of the two belts. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a plan view of an industrial robot according to an embodiment of the present invention. [Figure 2] Figure 2 is a rear view of a part of the industrial robot shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view illustrating the configuration of the arm shown in Figure 1. [Figure 4]FIG. 4 is a cross-sectional view for explaining the configuration of the joint portion shown in FIG. 1. [Figure 5] FIG. 5 is a diagram showing the first pulley, the upper pulley, the first belt, and the like as viewed from the H-H direction in FIG. 4. [Figure 6] FIG. 6 is a diagram showing the first pulley, the lower pulley, the second belt, and the like as viewed from the J-J direction in FIG. 4. [Figure 7] FIG. 7 is a cross-sectional view for explaining the configuration of the first belt shown in FIG. 5. [Figure 8] FIG. 8 is a diagram for explaining a method of adjusting the tension of the first belt and the second belt shown in FIG. 5 and FIG. 6. [Mode for Carrying Out the Invention]

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0016] (Overall Configuration of Industrial Robot) FIG. 1 is a plan view of an industrial robot 2 according to an embodiment of the present invention. FIG. 2 is a rear view of a part of the industrial robot 2 shown in FIG. 1. FIG. 3 is a schematic cross-sectional view for explaining the configuration of the arms 7 and 8 shown in FIG. 1.

[0017] The industrial robot 2 of the present embodiment (hereinafter referred to as "robot 2") is a horizontal articulated robot for transporting a semiconductor wafer 3 (hereinafter referred to as "wafer 3") which is an object to be transported. The wafer 3 is formed in a thin disk shape. The robot 2 includes two hands 5 and 6 on which the wafer 3 is mounted, an arm 7 to which the hand 5 is rotatably connected at the distal end portion, an arm 8 to which the hand 6 is rotatably connected at the distal end portion, a main body portion 9 (see FIG. 3) to which the proximal end portion of the arm 7 and the proximal end portion of the arm 8 are rotatably connected, and a case body 10 in which the main body portion 9 is accommodated. That is, the robot 2 is a double-arm type robot.

[0018] Arm 7 is a multi-joint arm that extends and retracts in the horizontal direction. The arm 7 includes an arm portion 13 whose base end is rotatably connected to the main body portion 9, and an arm portion 16 whose base end is rotatably connected to the distal end portion of the arm portion 13. The arm 7 of the present embodiment is composed of the arm portion 13 and the arm portion 14. The arm portion 14 is disposed above the arm portion 13. The base end portion of the hand 5 is rotatably connected to the distal end portion of the arm portion 14. The base end portion of the hand 5 is disposed above the distal end portion of the arm portion 14.

[0019] Similar to the arm 7, the arm 8 is a multi-joint arm that extends and retracts in the horizontal direction. The arm 8 includes an arm portion 15 whose base end is rotatably connected to the main body portion 9, and an arm portion 16 whose base end is rotatably connected to the distal end portion of the arm portion 15. The arm 8 of the present embodiment is composed of the arm portion 15 and the arm portion 16. The arm portion 16 is disposed above the arm portion 15. The base end portion of the hand 6 is rotatably connected to the distal end portion of the arm portion 16. The base end portion of the hand 6 is disposed above the distal end portion of the arm portion 16.

[0020] The arms 7 and 8 are capable of extending and retracting in the horizontal direction between a position where the arms 7 and 8 extend such that the distal ends of the hands 5 and 6 move away from the main body portion 9, and a position where the arms 7 and 8 retract such that the distal ends of the hands 5 and 6 approach the main body portion 9. When the wafer 3 is transported by the hand 5, the arm 7 extends and retracts relative to the main body portion 9 so that the hand 5 moves linearly while the hand 5 faces a fixed direction. When the wafer 3 is transported by the hand 6, the arm 8 extends and retracts relative to the main body portion 9 so that the hand 6 moves linearly while the hand 6 faces a fixed direction.

[0021] The base end of arm portion 13 and the base end of arm portion 15 overlap in the vertical direction. In this embodiment, the base end of arm portion 13 is positioned below the base end of arm portion 15. Also, the base ends of arm portion 13 and arm portion 15 are positioned above the main body portion 9. The tip of arm portion 14 and the tip of arm portion 16 overlap in the vertical direction when arms 7 and 8 are retracted to a predetermined reference position. That is, when arms 7 and 8 are retracted to a predetermined reference position, hands 5 and 6 overlap in the vertical direction.

[0022] In this configuration, the tip of arm 14 is positioned above the tip of arm 16. That is, hand 5 is positioned above hand 6. When viewing robot 2 from above with arms 7 and 8 retracted to their reference positions, arms 7 and 8 are bent symmetrically, and are positioned symmetrically. The more specific configuration of arms 7 and 8 will be described later.

[0023] Robot 2 includes a first arm drive mechanism that rotates arm sections 13 and 14 to extend and retract arm 7, and a second arm drive mechanism that rotates arm sections 15 and 16 to extend and retract arm 8. The first and second arm drive mechanisms are housed in a case body 10. The first arm drive mechanism includes a hollow pivot shaft 18 (see Figure 3) rotatably held in the main body 9, and a motor, etc., for rotating the pivot shaft 18. The second arm drive mechanism includes a pivot shaft 19 (see Figure 3) rotatably held in the main body 9, and a motor, etc., for rotating the pivot shaft 19.

[0024] The pivot shafts 18 and 19 are rotatable relative to the main body 9 with the vertical direction as the axis of rotation. The pivot shaft 19 is located on the inner circumference side of the pivot shaft 18. The base end of the arm portion 13 is fixed to the upper end of the pivot shaft 18. The base end of the arm portion 15 is fixed to the upper end of the pivot shaft 19. The axis of the pivot shaft 18 and the axis of the pivot shaft 19 coincide. That is, the rotation center of the arm portion 13 relative to the main body 9 and the rotation center of the arm portion 15 relative to the main body 9 coincide.

[0025] Furthermore, robot 2 is equipped with a lifting mechanism that raises and lowers arms 7, 8, main body 9, first arm drive mechanism and second arm drive mechanism relative to the case body 10, and a rotation mechanism that rotates arms 7, 8, main body 9, first arm drive mechanism, second arm drive mechanism and lifting mechanism relative to the case body 10 with the vertical direction as the axis of rotation. The lifting mechanism and the rotation mechanism are housed in the case body 10.

[0026] (Arm configuration) In this embodiment, arms 7 and 8 are parallel link arms having two parallel link mechanisms 22. Arm section 13 is composed of two (a pair) parallel arm sections 23 and 24 that are parallel to each other, and arm section 14 is composed of two parallel arm sections 25 and 26 that are parallel to each other. Arm section 15 is composed of two parallel arm sections 27 and 28 that are parallel to each other, and arm section 16 is composed of two parallel arm sections 29 and 30 that are parallel to each other. In other words, arm 7 is equipped with parallel arm sections 23 to 26, and arm 8 is equipped with parallel arm sections 27 to 30.

[0027] The parallel arm sections 23-30 are formed of, for example, an aluminum alloy. Parallel arm sections 23 and 24 are positioned at the same height, and parallel arm sections 25 and 26 are positioned at the same height. Parallel arm sections 27 and 28 are positioned at the same height, and parallel arm sections 29 and 30 are positioned at the same height. In this embodiment, parallel arm sections 23 and 27 are the first parallel arm sections, parallel arm sections 24 and 28 are the second parallel arm sections, parallel arm sections 25 and 29 are the third parallel arm sections, and parallel arm sections 26 and 30 are the fourth parallel arm sections.

[0028] The base ends of the parallel arm sections 23, 24, 27, and 28 are rotatably connected to the main body section 9. In this embodiment, the base end of the parallel arm section 23 is fixed to the upper end of the pivot shaft 18, and the base end of the parallel arm section 27 is fixed to the upper end of the pivot shaft 19. The hands 5 are rotatably connected to the tips of the parallel arm sections 25 and 26. The hands 6 are rotatably connected to the tips of the parallel arm sections 29 and 30. The base end of the parallel arm section 25 is rotatably connected to the tip of the parallel arm section 23, and the base end of the parallel arm section 26 is rotatably connected to the tip of the parallel arm section 24. The base end of the parallel arm section 29 is rotatably connected to the tip of the parallel arm section 27, and the base end of the parallel arm section 30 is rotatably connected to the tip of the parallel arm section 28.

[0029] In the horizontal direction, the distance between the pivot center of the parallel arm portion 23 relative to the main body portion 9 and the pivot center of the parallel arm portion 25 relative to the parallel arm portion 23 is equal to the distance between the pivot center of the parallel arm portion 24 relative to the main body portion 9 and the pivot center of the parallel arm portion 26 relative to the parallel arm portion 24, the distance between the pivot center of the parallel arm portion 25 relative to the parallel arm portion 23 and the pivot center of the hand 5 relative to the parallel arm portion 25, and the distance between the pivot center of the parallel arm portion 26 relative to the parallel arm portion 24 and the pivot center of the hand 5 relative to the parallel arm portion 26.

[0030] Furthermore, in the horizontal direction, these distances are equal to the distance between the pivot center of the parallel arm portion 27 relative to the main body portion 9 and the pivot center of the parallel arm portion 29 relative to the parallel arm portion 27, the distance between the pivot center of the parallel arm portion 28 relative to the main body portion 9 and the pivot center of the parallel arm portion 30 relative to the parallel arm portion 28, the distance between the pivot center of the parallel arm portion 29 relative to the parallel arm portion 27 and the pivot center of the hand 6 relative to the parallel arm portion 29, and the distance between the pivot center of the parallel arm portion 30 relative to the parallel arm portion 28 and the pivot center of the hand 6 relative to the parallel arm portion 30.

[0031] The parallel arm sections 25 and 26 are formed in an oval, flat plate shape with the vertical direction being the thickness direction. When viewed from a direction perpendicular to the longitudinal direction and the vertical direction of the parallel arm sections 25 and 26, the shape of the parallel arm sections 25 and 26 is a straight line with the tip and base ends of the parallel arm sections 25 and 26 positioned at the same height. The parallel arm sections 27 and 28 are formed in an oval, flat plate shape with the vertical direction being the thickness direction. When viewed from a direction perpendicular to the longitudinal direction and the vertical direction of the parallel arm sections 27 and 28, the shape of the parallel arm sections 27 and 28 is a straight line with the tip and base ends of the parallel arm sections 27 and 28 positioned at the same height.

[0032] When viewed from above, the parallel arm sections 23 and 24 have an oval shape. As described above, the base end of arm section 13 is positioned below the base end of arm section 15, and the base ends of parallel arm sections 23 and 24 are positioned below the base ends of parallel arm sections 27 and 28. Parallel arm sections 23 and 24 are bent vertically so that the tips of parallel arm sections 23 and 24 and the tips of parallel arm sections 27 and 28 are at the same height. Parallel arm sections 23 and 24 are bent in a stepped shape (Z-bend shape).

[0033] When viewed from above, the parallel arm sections 29 and 30 have an oval shape. As described above, the tip of arm section 14 is positioned above the tip of arm section 16, and the tips of parallel arm sections 25 and 26 are positioned above the tips of parallel arm sections 29 and 30. Parallel arm sections 29 and 30 are bent vertically so that the base ends of parallel arm sections 25 and 26 and the base ends of parallel arm sections 29 and 30 are at the same height. Parallel arm sections 29 and 30 are bent in a stepped shape.

[0034] (Joint structure) Figure 4 is a cross-sectional view illustrating the configuration of the joint 33 shown in Figure 1. Figure 5 shows the pulley 45, upper pulley 50, and belt 47, etc., from the HH direction in Figure 4. Figure 6 shows the pulley 45, lower pulley 51, and belt 48, etc., from the JJ direction in Figure 4. Figure 7 is a cross-sectional view illustrating the configuration of the belt 47 shown in Figure 5. Note that in Figure 4, hatching is applied only to the cross-sections of some of the components.

[0035] Arm 7 is equipped with a joint portion 33 that connects arm portion 13 and arm portion 14. That is, arm 7 is equipped with a joint portion 33 that connects parallel arm portion 23 and parallel arm portion 25, and parallel arm portion 24 and parallel arm portion 26. Arm 8 is equipped with a joint portion 34 that connects arm portion 15 and arm portion 16. That is, arm 8 is equipped with a joint portion 34 that connects parallel arm portion 27 and parallel arm portion 29, and parallel arm portion 28 and parallel arm portion 30.

[0036] As described above, the arm portion 13 is bent so that the tip of the arm portion 13 and the tip of the arm portion 15 are at the same height, and the arm portion 16 is bent so that the base end of the arm portion 14 and the base end of the arm portion 16 are at the same height. In other words, the vertical length of the joint portion 33 and the vertical length of the joint portion 34 are equal. In this embodiment, the joint portion 33 and the joint portion 34 have the same structure and shape.

[0037] The joint 33 includes a pivot shaft 35 to which the tip of the parallel arm 23 is fixed, a pivot shaft 36 to which the base end of the parallel arm 26 is fixed, and a shaft holding member 37 that rotatably holds the pivot shafts 35 and 36. In other words, the joint 33 has the pivot shafts 35 and 36 and the shaft holding member 37 arranged therein. In this embodiment, the pivot shaft 35 is the first pivot shaft, and the pivot shaft 36 is the second pivot shaft.

[0038] The pivot shafts 35 and 36 are formed in a cylindrical shape with the vertical direction as the axial direction. That is, the axial direction of the pivot shafts 35 and 36 coincides with the vertical direction. The pivot shafts 35 and 36 are rotatable with the vertical direction as the axial direction of rotation. The pivot shafts 35 and 36 are arranged with a gap between them in the horizontal direction. The shaft holding member 37 holds the lower ends of the pivot shafts 35 and 36. A bearing 38 is positioned between the pivot shafts 35 and 36 and the shaft holding member 37. The bearing 38 is a rolling bearing having an inner ring fixed to the pivot shafts 35 and 36, an outer ring fixed to the shaft holding member 37, and rolling elements such as rollers positioned between the inner ring and the outer ring.

[0039] The tip of the parallel arm section 23 is fixed to the pivot shaft 35 above the shaft holding member 37. The base end of the parallel arm section 25 is rotatably attached to the pivot shaft 35. Specifically, the base end of the parallel arm section 25 is rotatably attached to the upper end of the pivot shaft 35. A bearing 39 is positioned between the base end of the parallel arm section 25 and the pivot shaft 35. The base end of the parallel arm section 26 is fixed to the upper end of the pivot shaft 36. The tip of the parallel arm section 24 is rotatably attached to the pivot shaft 36. Specifically, the tip of the parallel arm section 24 is rotatably attached to the pivot shaft 36 above the shaft holding member 37. A bearing 40 is positioned between the tip of the parallel arm section 24 and the pivot shaft 36.

[0040] Furthermore, the joint 33 includes a pulley 45 fixed to the pivot shaft 35, a pulley 46 fixed to the pivot shaft 36, and two belts 47 and 48 formed in a strip shape. In other words, the joint 33 is equipped with pulleys 45 and 46 and belts 47 and 48 for power transmission to operate the arm 7. The pulley 45 rotates together with the pivot shaft 35 with the vertical direction as the axis of rotation. The pulley 46 rotates together with the pivot shaft 36 with the vertical direction as the axis of rotation. In this embodiment, pulley 45 is the first pulley, pulley 46 is the second pulley, belt 47 is the first belt, and belt 48 is the second belt.

[0041] Pulley 45 is fixed to the lower end of the pivot shaft 35. Pulley 46 is fixed to the lower end of the pivot shaft 36. One end of belts 47 and 48 is fixed to pulley 45. The other end of belts 47 and 48 is fixed to pulley 46. Pulleys 45 and 46 and belts 47 and 48 are positioned below the tip ends of parallel arm sections 23 and 24 and the base ends of parallel arm sections 25 and 26. Pulleys 45 and 46 and belts 47 and 48 are also positioned below the shaft holding member 37. A cover 49 that covers pulleys 45 and 46 is attached to the lower surface of the shaft holding member 37.

[0042] The pulley 46 comprises an upper pulley 50 and a lower pulley 51 that overlap vertically. The pulley 46 is composed of an upper pulley 50 and a lower pulley 51. The lower pulley 51 is positioned below the upper pulley 50. The outer diameters of the upper pulley 50 and the lower pulley 51 are equal. The upper pulley 50 is fixed to the pivot shaft 36. The lower pulley 51 is fixed to the upper pulley 50. Specifically, the lower pulley 51 is fixed to the upper pulley 50 by a plurality of screws 52. In this embodiment, the lower pulley 51 is fixed to the upper pulley 50 by six screws 52 arranged at a constant pitch in the circumferential direction of the upper pulley 50 and the lower pulley 51.

[0043] The inner diameter of the upper pulley 50 is smaller than the inner diameter of the lower pulley 51. The upper pulley 50 has an annular contact surface 50b that contacts the inner circumferential surface 51b of the lower pulley 51. In this embodiment, the lower pulley 51 is positioned relative to the upper pulley 50 in the radial direction of the upper pulley 50 by the contact surface 50b of the lower pulley 51 and the inner circumferential surface 51b of the lower pulley 50. In this embodiment, the contact surface 50b and the inner circumferential surface 51b serve as positioning parts for positioning the lower pulley 51 relative to the upper pulley 50 in the radial direction of the upper pulley 50 and the lower pulley 51.

[0044] The lower pulley 51 has screw placement holes 51c formed therein, in which a portion of the shaft of the screw 52 is positioned. As shown in Figure 6, in this embodiment, six screw placement holes 51c are formed in the lower pulley 51, arranged at a constant pitch in the circumferential direction of the lower pulley 51. The screw placement holes 51c are through holes that penetrate the lower pulley 51 in the vertical direction. Furthermore, the screw placement holes 51c are formed in an elongated shape, with the longitudinal direction being perpendicular to the radial direction and vertical direction of the lower pulley 51. In other words, the screw placement holes 51c are elongated holes.

[0045] Furthermore, the lower pulley 51 has a first hole 51d that penetrates the lower pulley 51 in the vertical direction. The first hole 51d is used when adjusting the tension of the belts 47 and 48. The first hole 51d is formed in one location. The first hole 51d is formed as an elongated hole with its longitudinal direction inclined with respect to the direction perpendicular to the radial and vertical directions of the lower pulley 51. In this embodiment, the first hole 51d is formed as an elongated hole with its longitudinal direction aligned with the radial direction of the lower pulley 51. That is, the first hole 51d is an elongated hole with its longitudinal direction aligned with the radial direction of the lower pulley 51. The first hole 51d is located in the circumferential direction of the lower pulley 51, at an intermediate position between two circumferentially adjacent screw holes 51c.

[0046] The upper pulley 50 has screw holes 50c formed therein, into which a screw 52 engages. As shown in Figure 5, in this embodiment, six screw holes 50c are formed in the upper pulley 50, arranged at a constant pitch in the circumferential direction of the upper pulley 50. The screw holes 50c are formed from the lower surface of the upper pulley 50 toward the upper side. In this embodiment, the screw holes 50c penetrate the upper pulley 50 in the vertical direction. The screw 52 is tightened into the screw holes 50c from below. Note that the screw holes 50c do not necessarily have to penetrate the upper pulley 50 in the vertical direction.

[0047] Furthermore, the upper pulley 50 has a round second hole 50d that overlaps with the first hole 51d in the vertical direction. The second hole 50d is used when adjusting the tension of the belts 47 and 48. The second hole 50d is formed in one location. The second hole 50d is formed from the lower surface of the upper pulley 50 toward the upper side. In this embodiment, the second hole 50d penetrates the upper pulley 50 in the vertical direction. However, the second hole 50d does not necessarily have to penetrate the upper pulley 50 in the vertical direction.

[0048] The lower surface of the portion of the upper pulley 50 where the second hole 50d is formed is in contact with the upper surface of the portion of the lower pulley 51 where the first hole 51d is formed. The second hole 50d is connected to the first hole 51d. That is, the second hole 50d is connected to the first hole 51d. The inner diameter of the second hole 50d is smaller than the width of the elongated first hole 51d. For example, the inner diameter of the second hole 50d is about one-third of the width of the first hole 51d. However, the inner diameter of the second hole 50d and the width of the first hole 51d may be equal.

[0049] As described above, the upper pulley 50 is fixed to the pivot shaft 36. The joint portion 33 is configured to fix the upper pulley 50 to the pivot shaft 36 and includes a cylindrical fixing member 55 fixed to the lower end surface of the pivot shaft 36 and a plurality of screws 56 for fixing the fixing member 55 to the pivot shaft 36. Screw holes are formed on the lower surface of the pivot shaft 36 into which the screws 56 engage, and through holes are formed in the fixing member 55 into which a part of the shaft portion of the screws 56 is positioned. A flange portion 55b is formed at the lower end of the fixing member 55, extending radially outward from the upper pulley 50. In this embodiment, the upper pulley 50 is fixed to the pivot shaft 36 by being sandwiched between the inner ring of the bearing 38 and the flange portion 55b. When screw 56 is loosened, the upper pulley 50 becomes rotatable around the pivot shaft 36.

[0050] Belt 47 is a rubber belt made of rubber with multiple metal core wires 57 embedded inside, extending in the longitudinal direction of the belt 47, which is formed in a strip shape (see Figure 7). The core wires 57 are positioned at the center in the thickness direction of the belt 47. That is, the distance L1 between the core wires 57 and one surface of the belt 47 is equal to the distance L2 between the core wires 57 and the other surface of the belt 47. Belt 48 is constructed in the same way as belt 47.

[0051] As described above, one end of belts 47 and 48 is fixed to pulley 45. Also, as described above, the other ends of belts 47 and 48 are fixed to pulley 46. Specifically, the other end of belt 47 is fixed to the upper pulley 50, and the other end of belt 48 is fixed to the lower pulley 51. One end of belts 47 and 48 is fixed to the outer surface of pulley 45 by screw 58. The other end of belt 47 is fixed to the outer surface of upper pulley 50 by screw 58, and the other end of belt 48 is fixed to the outer surface of lower pulley 51 by screw 58.

[0052] The winding direction of belt 47 around pulley 45 is opposite to the winding direction of belt 48 around pulley 45. Also, the winding direction of belt 47 around pulley 46 is opposite to the winding direction of belt 48 around pulley 46. Specifically, the winding direction of belt 47 around the upper pulley 50 is opposite to the winding direction of belt 48 around the lower pulley 51. In other words, belts 47 and 48 are attached to pulleys 45 and 46 in a diagonal pattern.

[0053] More specifically, belt 47 is wrapped around pulley 45 in a clockwise direction as shown in Figures 5 and 6 (hereinafter referred to as "clockwise") from the fixing position of belt 47 on pulley 45, and belt 48 is wrapped around pulley 45 in a counterclockwise direction as shown in Figures 5 and 6 (hereinafter referred to as "counterclockwise") from the fixing position of belt 48 on pulley 45. Furthermore, belt 47 is wrapped clockwise from the fixing position of belt 47 on upper pulley 50, and belt 48 is wrapped counterclockwise from the fixing position of belt 48 on lower pulley 51. For example, belts 47 and 48 are wrapped around pulley 45 at an angle of approximately 90°. Also, for example, belt 47 is wrapped around upper pulley 50 at an angle of approximately 90°, and belt 48 is wrapped around lower pulley 51 at an angle of approximately 90°.

[0054] As described above, the joint portion 33 and the joint portion 34 have the same structure and shape. The joint portion 34, like the joint portion 33, includes a pivot shaft 35 to which the tip of the parallel arm portion 27 is fixed, a pivot shaft 36 to which the base end of the parallel arm portion 30 is fixed, a shaft holding member 37 that rotatably holds the pivot shafts 35 and 36, a pulley 45 fixed to the pivot shaft 35, a pulley 46 fixed to the pivot shaft 36, and two belts 47 and 48 formed in a strip shape.

[0055] The tip of the parallel arm section 27 is fixed to the pivot shaft 35 above the shaft holding member 37. The base end of the parallel arm section 29 is rotatably attached to the upper end of the pivot shaft 35. A bearing 39 is positioned between the base end of the parallel arm section 29 and the pivot shaft 35. The base end of the parallel arm section 30 is fixed to the upper end of the pivot shaft 36. The tip of the parallel arm section 28 is rotatably attached to the pivot shaft 36 above the shaft holding member 37. A bearing 40 is positioned between the tip of the parallel arm section 28 and the pivot shaft 36.

[0056] (How to adjust belt tension) Figure 8 is a diagram illustrating the method for adjusting the tension of belts 47 and 48 shown in Figures 5 and 6. In Figure 8, hatching is applied only to the cross-sections of some of the components.

[0057] When adjusting the tension of belts 47 and 48 fixed to pulleys 45 and 46, a tension adjustment jig 62 is used. The jig 62 comprises a cylindrical jig body 62b, a cylindrical pivot axis 62c connected to one end face of the jig body 62b, and a handle portion 62d that the operator grips when rotating the jig 62. If the end of the jig body 62b to which the pivot axis 62c is connected is considered one end of the jig body 62b, and the opposite end of the jig body 62b is considered the other end of the jig body 62b, then the handle portion 62d is connected to the other end of the jig body 62b.

[0058] The pivot axis 62c protrudes outward in the axial direction from one end face of the jig body 62b. The outer diameter of the pivot axis 62c is smaller than the outer diameter of the jig body 62b. The axis of the pivot axis 62c is offset from the axis of the jig body 62b. In other words, the jig 62 is an eccentric jig in which the axis of the pivot axis 62c is positioned offset from the axis of the jig body 62b. When the tension of the belts 47 and 48 is adjusted, the pivot axis 62c is positioned in the second hole 50d. The outer diameter of the pivot axis 62c is approximately equal to the inner diameter of the second hole 50d. Also, when the tension of the belts 47 and 48 is adjusted, a part of the jig body 62b (specifically, one end of the jig body 62b) is positioned in the first hole 51d. The outer diameter of the jig body 62b is approximately equal to the width of the first hole 51d, which is formed in an elongated shape (see Figure 6).

[0059] When adjusting the tension of the belts 47 and 48 fixed to pulleys 45 and 46, first loosen the fixed state of the upper pulley 50 and lower pulley 51. Specifically, loosen the screw 56 to loosen the fixed state of the upper pulley 50 relative to the pivot shaft 36, and loosen the screw 52 to loosen the fixed state of the lower pulley 51 relative to the upper pulley 50. Also, attach the jig 62 to the upper pulley 50 and lower pulley 51, position the pivot center shaft 62c in the second hole 50d, and position one end of the jig body 62b in the first hole 51d. The jig 62 is attached to the upper pulley 50 and lower pulley 51 from below.

[0060] In this state, the jig body 62b is rotated around the pivot axis 62c to rotate the upper pulley 50 and the lower pulley 51, thereby adjusting the tension of the belts 47 and 48. For example, if the jig body 62b is rotated clockwise from the state shown by the dashed line in Figure 6, the lower pulley 51 rotates clockwise relative to the upper pulley 50, and the upper pulley 50 rotates counterclockwise relative to the pivot axis 36, increasing the tension of the belts 47 and 48 (see arrows in Figures 5 and 6).

[0061] Furthermore, when the jig body 62b is rotated counterclockwise from the state shown by the dashed line in Figure 6, the lower pulley 51 rotates counterclockwise relative to the upper pulley 50, and the upper pulley 50 rotates clockwise relative to the pivot axis 36, causing the tension of the belts 47 and 48 to decrease. The amount of rotation (rotation angle) of the upper pulley 50 and the amount of rotation (rotation angle) of the lower pulley 51 become equal when the jig body 62b is rotated.

[0062] After adjusting the tension of belts 47 and 48, the upper pulley 50 and lower pulley 51 are fixed in place. Specifically, the upper pulley 50 is fixed to the pivot shaft 36 by tightening screw 56, and the lower pulley 51 is fixed to the upper pulley 50 by tightening screw 52. After adjusting the tension of belts 47 and 48, the jig 62 is removed from the upper pulley 50 and lower pulley 51 by moving it downwards.

[0063] (Main effects of this form) As described above, in this embodiment, the pulley 46 includes an upper pulley 50 to which the end of the belt 47 is fixed, and a lower pulley 51 to which the end of the belt 48 is fixed. In addition, in this embodiment, in order to position the lower pulley 51 relative to the upper pulley 50 in the radial direction of the upper pulley 50 and the lower pulley 51, a contact surface 50b is formed on the upper pulley 50 and an inner circumferential surface 51b is formed on the lower pulley 51. Furthermore, in this embodiment, the first hole 51d formed in the lower pulley 51 is formed in the shape of an elongated hole with the radial direction of the lower pulley 51 as the longitudinal direction, and the upper pulley 50 has a round second hole 50d that overlaps with the first hole 51d in the vertical direction and is connected to the first hole 51d.

[0064] Therefore, in this embodiment, as described above, by loosening the fixed state of the upper pulley 50 and the lower pulley 51, and attaching the jig 62 to the upper pulley 50 and the lower pulley 51, with the pivot axis 62c positioned in the second hole 50d and one end of the jig body 62b positioned in the first hole 51d, the jig body 62b is rotated with the pivot axis 62c as the pivot point, thereby rotating the upper pulley 50 and the lower pulley 51 in opposite directions, making it possible to increase or decrease the tension of the belts 47 and 48 together. Consequently, in this embodiment, even if the two belts 47 and 48 are attached to the pulleys 45 and 46 in a crisscross pattern, it becomes possible to easily adjust the tension of the two belts 47 and 48.

[0065] In this embodiment, the pulleys 45, 46 and belts 47, 48 are positioned below the tip portions of the parallel arm portions 23, 24, 27, 28 and the base portions of the parallel arm portions 25, 26, 29, 30. In addition, in this embodiment, a first hole 51d is formed in the lower pulley 51 and a second hole 50d is formed in the upper pulley 50. Therefore, in this embodiment, the jig 62 can be easily attached to the upper pulley 50 and the lower pulley 51 from below the joint portions 33, 34.

[0066] Furthermore, in this embodiment, since the pulleys 45 and 46 are positioned below the tips of the parallel arm sections 23, 24, 27, and 28 and the base ends of the parallel arm sections 25, 26, 29, and 30, it becomes possible to expand the area in which the pulleys 45 and 46 can be installed. Therefore, in this embodiment, it becomes possible to increase the outer diameter of the pulleys 45 and 46, and as a result, it becomes possible to improve the operational accuracy of the arms 7 and 8.

[0067] In this embodiment, a screw hole 50c is formed in the upper pulley 50, into which a screw 52 engages, and a screw arrangement hole 51c is formed in the lower pulley 51, into which a portion of the shaft of the screw 52 is positioned. Furthermore, in this embodiment, the screw arrangement hole 51c penetrates the lower pulley 51 in the vertical direction and is formed as an elongated hole with its longitudinal direction perpendicular to the radial and vertical directions of the lower pulley 51. Therefore, in this embodiment, even if the upper pulley 50 and the lower pulley 51 can be rotated in opposite directions using a jig 62, the lower pulley 51 can be easily fixed to the upper pulley 50.

[0068] In this embodiment, belts 47 and 48 are rubber belts with multiple metal core wires 57 embedded inside that extend in the longitudinal direction of belts 47 and 48. Therefore, in this embodiment, even if belts 47 and 48 deform by meandering, it is possible to suppress the concentration of stress at specific points on belts 47 and 48. Consequently, in this embodiment, it is possible to suppress the breakage of belts 47 and 48.

[0069] In this embodiment, multiple core wires 57 are positioned at the center of the belts 47 and 48 in the thickness direction. Therefore, in this embodiment, it is possible to reduce the difference between the rotation speed of pulley 46 when pulley 45 rotates in one direction and the rotation speed of pulley 46 when pulley 45 rotates in another direction, and also to reduce the difference between the amount of rotation of pulley 46 when pulley 45 rotates by a predetermined amount in one direction and the amount of rotation of pulley 46 when pulley 45 rotates by a predetermined amount in another direction. Consequently, in this embodiment, it is possible to operate arms 7 and 8 appropriately.

[0070] (Other embodiments) The above-described embodiments are examples of preferred embodiments of the present invention, but are not limited thereto, and various modifications can be made without altering the essence of the invention.

[0071] In the above-described configuration, the longitudinal direction of the first hole 51d does not need to coincide with the radial direction of the lower pulley 51, as long as it is inclined with respect to the direction perpendicular to the radial and vertical directions of the lower pulley 51. However, if the longitudinal direction of the first hole 51d coincides with the radial direction of the lower pulley 51, as in the above-described configuration, it becomes possible to increase the amount of rotation of the upper pulley 50 and the lower pulley 51 when the jig body 62b is rotated by a certain amount when adjusting the tension of the belts 47 and 48 using the jig 62. Therefore, it becomes possible to adjust the tension of the belts 47 and 48 efficiently.

[0072] In the above-described configuration, the screw placement hole 51c may be formed as an elongated hole with the circumferential direction of the lower pulley 51 as its longitudinal direction. Alternatively, in the above-described configuration, the upper pulley 50 may be directly fixed to the pivot shaft 36 by a screw 56. In this case, a through hole is formed in the upper pulley 50 in which a portion of the shaft of the screw 56 is placed. This through hole is formed as an elongated hole with the longitudinal direction being perpendicular to the radial and vertical directions of the upper pulley 50, or as an elongated hole with the circumferential direction of the upper pulley 50 as its longitudinal direction.

[0073] In the above-described configuration, the lower pulley 51 may be fixed to the pivot shaft 36, and the upper pulley 50 may be fixed to the lower pulley 51. In this case, a screw hole corresponding to the screw hole 50c is formed in the lower pulley 51, and a screw arrangement hole corresponding to the screw arrangement hole 51c is formed in the upper pulley 50. Furthermore, in the above-described configuration, if the jig 62 can be attached to the upper pulley 50 and the lower pulley 51 from above, a first hole corresponding to the first hole 51d may be formed in the upper pulley 50, and a second hole corresponding to the second hole 50d may be formed in the lower pulley 51.

[0074] In the above-described embodiment, instead of pulley 46, pulley 45 may be provided with an upper pulley 50 and a lower pulley 51 that overlap in the vertical direction. Also, in the above-described embodiment, the core wire 57 may be positioned offset from the center in the thickness direction of belts 47 and 48. Furthermore, in the above-described embodiment, belts 47 and 48 may be rubber belts without embedded core wires 57, or steel belts made of steel plates. Also, in the above-described embodiment, the number of hands and arms provided by robot 2 may be one. For example, robot 2 may be provided with only one hand 5 and one arm 7. Also, in the above-described embodiment, the object to be transported by robot 2 may be something other than wafers 3.

[0075] (Configuration of this technology) Furthermore, this technology can be configured as follows: (1) comprising a hand on which an object to be transported is mounted, an arm to which the tip of the hand is rotatably connected, and a main body to which the base end of the arm is rotatably connected, The aforementioned arm is a parallel link arm having two parallel link mechanisms, comprising a first parallel arm section and a second parallel arm section that are parallel to each other, and a third parallel arm section and a fourth parallel arm section that are parallel to each other. The base end of the first parallel arm and the base end of the second parallel arm are rotatably connected to the main body. The base end of the third parallel arm is rotatably connected to the tip of the first parallel arm, The base end of the fourth parallel arm is rotatably connected to the tip of the second parallel arm, The tip of the third parallel arm and the tip of the fourth parallel arm are rotatably connected to the hand. The joints that form the connection between the first parallel arm and the third parallel arm, and the connection between the second parallel arm and the fourth parallel arm, are provided with a first pivot shaft to which the tip of the first parallel arm is fixed, a second pivot shaft to which the base end of the fourth parallel arm is fixed, a first pulley fixed to the first pivot shaft, a second pulley fixed to the second pivot shaft, and a first and second belts formed in a strip shape. The axial direction of the first pivot axis and the axial direction of the second pivot axis coincide with the vertical direction. The base end of the third parallel arm portion is rotatably attached to the first pivot shaft, The tip of the second parallel arm is rotatably mounted on the second pivot shaft. One end of the first belt and one end of the second belt are fixed to the first pulley. The other end of the first belt and the other end of the second belt are fixed to the second pulley. The winding direction of the first belt around the first pulley and the winding direction of the second belt around the first pulley are in opposite directions. The winding direction of the first belt around the second pulley and the winding direction of the second belt around the second pulley are in opposite directions. The first pulley or the second pulley comprises an upper pulley and a lower pulley that overlap in the vertical direction, The end of the first belt is fixed to the upper pulley. The end of the second belt is fixed to the lower pulley. The upper pulley and the lower pulley are formed with a positioning portion for positioning the lower pulley relative to the upper pulley in the radial direction of the upper pulley and the lower pulley. A first hole is formed in either the upper pulley or the lower pulley, which penetrates the upper pulley or the lower pulley in the vertical direction. The first hole is formed in the shape of an elongated hole, with its longitudinal direction being inclined with respect to the directions perpendicular to the radial and vertical directions of the upper and lower pulleys. An industrial robot characterized in that the other of the upper pulley and the lower pulley has a second circular hole formed therein that overlaps with the first hole in the vertical direction and is connected to the first hole. (2) The industrial robot according to (1), characterized in that the first hole is formed in the shape of an elongated hole with the radial direction of the upper pulley and the lower pulley as the longitudinal direction. (3) The first pulley is fixed to the lower end of the first pivot shaft, The second pulley is fixed to the lower end of the second pivot shaft, The first pulley, the second pulley, the first belt, and the second belt are positioned below the tip of the first parallel arm, the tip of the second parallel arm, the base end of the third parallel arm, and the base end of the fourth parallel arm. The lower pulley, which is positioned below the upper pulley, has the first hole formed in it. The industrial robot according to (1) or (2), characterized in that the upper pulley has the second hole formed therein. (4) Either the upper pulley or the lower pulley is fixed to the other of the upper pulley or the lower pulley by a plurality of screws, A screw hole is formed in the other of the upper pulley and the lower pulley, into which the screw engages. A screw mounting hole is formed in either the upper pulley or the lower pulley, in which a portion of the screw shaft is positioned. The plurality of screw holes and the plurality of screw placement holes are arranged in the circumferential direction of the upper pulley and the lower pulley, The industrial robot according to any one of (1) to (3), characterized in that the screw arrangement hole penetrates either the upper pulley or the lower pulley in the vertical direction and is formed in the shape of an elongated hole with the longitudinal direction being perpendicular to the radial direction and vertical direction of the upper pulley and the lower pulley. (5) The industrial robot according to any one of (1) to (4), characterized in that the first belt and the second belt are rubber belts in which a plurality of metal core wires extending in the longitudinal direction of the first belt and the second belt are embedded inside. (6) The industrial robot according to (5), characterized in that the multiple core wires are arranged at the center in the thickness direction of the first belt and the second belt. (7) A method for adjusting the tension of the first belt and the second belt of an industrial robot described in any of (1) to (6), Either the upper pulley or the lower pulley is fixed to the other of the upper pulley or the lower pulley, and the other of the upper pulley or the lower pulley is fixed to the first pivot shaft or the second pivot shaft. The belt tension adjustment method is characterized by loosening the fixed state of the upper pulley and the lower pulley, attaching a jig to the upper pulley and the lower pulley, the jig having a cylindrical jig body with a portion of which is positioned in the first hole and a cylindrical pivot axis connected to one end face of the jig body and positioned in the second hole, with its axis offset from the axis of the jig body, and then rotating the jig body around the pivot axis to rotate the upper pulley and the lower pulley, thereby adjusting the tension of the first belt and the second belt, and then fixing the upper pulley and the lower pulley.

[0076] In this technology, it is preferable that the first hole is formed in the shape of an elongated hole with the radial direction of the upper pulley and the lower pulley as the longitudinal direction. With this configuration, for example, when adjusting the tension of the first belt and the second belt using the jig described above, it becomes possible to increase the amount of rotation of the upper pulley and the lower pulley when the jig body is rotated by a certain amount. Therefore, it becomes possible to adjust the tension of the first belt and the second belt efficiently.

[0077] In this technology, for example, the first pulley is fixed to the lower end of the first rotation shaft, and the second pulley is fixed to the lower end of the second rotation shaft. The first pulley, the second pulley, the first belt, and the second belt are positioned below the tip of the first parallel arm, the tip of the second parallel arm, the base of the third parallel arm, and the base of the fourth parallel arm. A first hole is formed in the lower pulley, which is positioned below the upper pulley, and a second hole is formed in the upper pulley.

[0078] In this case, the jig can be easily attached to the upper and lower pulleys from the underside of the joint. Furthermore, in this case, since the first and second pulleys are positioned below the tip of the first parallel arm, the tip of the second parallel arm, the base of the third parallel arm, and the base of the fourth parallel arm, the area in which the first and second pulleys can be installed can be expanded. Consequently, the outer diameters of the first and second pulleys can be increased, and as a result, the operational accuracy of the arms can be improved.

[0079] In this technology, it is preferable that either the upper pulley or the lower pulley is fixed to the other of the upper pulley or the lower pulley by a plurality of screws, that the other of the upper pulley or the lower pulley has screw holes into which the screws engage, that either the upper pulley or the lower pulley has a screw arrangement hole into which a part of the screw shaft is positioned, that the plurality of screw holes and the plurality of screw arrangement holes are arranged in the circumferential direction of the upper pulley and the lower pulley, that the screw arrangement holes penetrate either the upper pulley or the lower pulley in the vertical direction and are formed in the shape of elongated holes with the longitudinal direction being perpendicular to the radial direction and vertical direction of the upper pulley or the lower pulley. With this configuration, even if the upper pulley and the lower pulley can be rotated in opposite directions using a jig, it becomes possible to easily fix either the upper pulley or the lower pulley to the other of the upper pulley or the lower pulley.

[0080] In this technology, the first and second belts are preferably rubber belts in which multiple metal core wires extending in the longitudinal direction of the first and second belts are embedded inside. With this configuration, even if the first and second belts deform by meandering, for example, it becomes possible to suppress the concentration of stress at specific points on the first and second belts. Therefore, it becomes possible to suppress the breakage of the first and second belts.

[0081] In this technology, it is preferable that multiple core wires are positioned at the center in the thickness direction of the first and second belts. With this configuration, it is possible to reduce the difference between the rotation speed of the second pulley when the first pulley rotates in one direction and the rotation speed of the second pulley when the first pulley rotates in another direction, and it is also possible to reduce the difference between the amount of rotation of the second pulley when the first pulley rotates by a predetermined amount in one direction and the amount of rotation of the second pulley when the first pulley rotates by a predetermined amount in another direction. Therefore, it becomes possible to operate the arm appropriately. [Explanation of Symbols]

[0082] 2. Robots (Industrial Robots) 3. Wafer (semiconductor wafer, object to be transported) 5, 6 hands 7, 8 arms 9 Main body 22 Parallel link mechanism 23, 27 Parallel arm section (first parallel arm section) 24, 28 Parallel arm section (second parallel arm section) 25, 29 Parallel arm section (third parallel arm section) 26, 30 Parallel arm section (4th parallel arm section) 33, 34 Joints 35 rotation axis (1st rotation axis) 36 rotation axis (2nd rotation axis) 45 Pulley (1st pulley) 46 Pulley (2nd Pulley) 47 Belt (1st Belt) 48 Belt (2nd Belt) 50 Upper pulley 50b Contact surface (positioning part) 50c screw hole 50d Second hole 51 Lower pulley 51b Inner circumferential surface (positioning part) 51c Screw placement holes 51d Hole 1 52 screws 57 core wires 62 Jigs 62b Jig body 62c Rotation center axis

Claims

1. The system comprises a hand on which an object to be transported is mounted, an arm to which the tip of the hand is rotatably connected, and a main body to which the base end of the arm is rotatably connected. The aforementioned arm is a parallel link arm having two parallel link mechanisms, comprising a first parallel arm section and a second parallel arm section that are parallel to each other, and a third parallel arm section and a fourth parallel arm section that are parallel to each other. The base end of the first parallel arm and the base end of the second parallel arm are rotatably connected to the main body. The base end of the third parallel arm is rotatably connected to the tip of the first parallel arm, The base end of the fourth parallel arm is rotatably connected to the tip of the second parallel arm, The tip of the third parallel arm and the tip of the fourth parallel arm are rotatably connected to the hand. The joints that form the connection between the first parallel arm and the third parallel arm, and the connection between the second parallel arm and the fourth parallel arm, are provided with a first pivot shaft to which the tip of the first parallel arm is fixed, a second pivot shaft to which the base end of the fourth parallel arm is fixed, a first pulley fixed to the first pivot shaft, a second pulley fixed to the second pivot shaft, and a first and second belts formed in a strip shape. The axial direction of the first pivot axis and the axial direction of the second pivot axis coincide with the vertical direction. The base end of the third parallel arm portion is rotatably attached to the first pivot shaft, The tip of the second parallel arm is rotatably attached to the second pivot shaft. One end of the first belt and one end of the second belt are fixed to the first pulley. The other end of the first belt and the other end of the second belt are fixed to the second pulley. The winding direction of the first belt around the first pulley and the winding direction of the second belt around the first pulley are in opposite directions. The winding direction of the first belt around the second pulley and the winding direction of the second belt around the second pulley are in opposite directions. The first pulley or the second pulley comprises an upper pulley and a lower pulley that overlap in the vertical direction, The end of the first belt is fixed to the upper pulley. The end of the second belt is fixed to the lower pulley. The upper pulley and the lower pulley are formed with a positioning portion for positioning the lower pulley relative to the upper pulley in the radial direction of the upper pulley and the lower pulley. A first hole is formed in either the upper pulley or the lower pulley, which penetrates the upper pulley or the lower pulley in the vertical direction. The first hole is formed in the shape of an elongated hole, with its longitudinal direction being inclined with respect to the direction perpendicular to the radial and vertical directions of the upper and lower pulleys. An industrial robot characterized in that the other of the upper pulley and the lower pulley has a second circular hole formed therein that overlaps with the first hole in the vertical direction and is connected to the first hole.

2. The industrial robot according to claim 1, characterized in that the first hole is formed in the shape of an elongated hole with the radial direction of the upper pulley and the lower pulley as the longitudinal direction.

3. The first pulley is fixed to the lower end of the first pivot shaft, The second pulley is fixed to the lower end of the second pivot shaft, The first pulley, the second pulley, the first belt, and the second belt are positioned below the tip of the first parallel arm, the tip of the second parallel arm, the base end of the third parallel arm, and the base end of the fourth parallel arm. The lower pulley, which is positioned below the upper pulley, has the first hole formed in it. The industrial robot according to claim 1 or 2, characterized in that the upper pulley has the second hole formed therein.

4. Either the upper pulley or the lower pulley is fixed to the other of the upper pulley or the lower pulley by a plurality of screws. A screw hole is formed in the other of the upper pulley and the lower pulley, into which the screw engages. A screw mounting hole is formed in either the upper pulley or the lower pulley, in which a portion of the screw shaft is positioned. The plurality of screw holes and the plurality of screw placement holes are arranged in the circumferential direction of the upper pulley and the lower pulley, The industrial robot according to claim 1 or 2, characterized in that the screw arrangement hole penetrates either the upper pulley or the lower pulley in the vertical direction and is formed in the shape of an elongated hole with its longitudinal direction perpendicular to the radial direction and vertical direction of the upper pulley and the lower pulley.

5. The industrial robot according to claim 1 or 2, characterized in that the first belt and the second belt are rubber belts in which a plurality of metal core wires extending in the longitudinal direction of the first belt and the second belt are embedded inside.

6. The industrial robot according to claim 5, characterized in that the multiple core wires are arranged at the center in the thickness direction of the first belt and the second belt.

7. A method for adjusting the tension of the first belt and the second belt of an industrial robot according to claim 1 or 2, Either the upper pulley or the lower pulley is fixed to the other of the upper pulley or the lower pulley, and the other of the upper pulley or the lower pulley is fixed to the first pivot shaft or the second pivot shaft. The belt tension adjustment method is characterized by loosening the fixed state of the upper pulley and the lower pulley, attaching a jig to the upper pulley and the lower pulley, the jig having a cylindrical jig body with a portion of which is positioned in the first hole and a cylindrical pivot axis connected to one end face of the jig body and positioned in the second hole, with its axis offset from the axis of the jig body, and then rotating the jig body around the pivot axis to rotate the upper pulley and the lower pulley, thereby adjusting the tension of the first belt and the second belt, and then fixing the upper pulley and the lower pulley.

Images