Belt transmission mechanism and transport robot including the same

Abstract

To provide a structure which can expand rotation angles of two pulleys in a belt transmission mechanism which is formed including two steel belts attached to the two pulleys with winding directions set opposite to each other.SOLUTION: A belt transmission mechanism includes: pulleys 6A, 6B; steel belts 71, 72 having both ends 711, 712 and both ends 721, 722; and covers 91, 92. The pulley 6A has recessed parts 61, 62 recessed from an outer peripheral surface 60. A block member 81 is fixed to the end 711 and the block member 81 is disposed in the recessed part 61. The cover 91 is fixedly disposed at the recessed part 61 so as to enclose the block member 81 and has an outer peripheral surface 910 having the same diameter as the outer peripheral surface 60 of the pulley 6A. A block member 82 is fixed to the end 721 and the block member 82 is disposed at the recessed part 62. The cover 92 is fixedly disposed at the recessed part 62 so as to enclose the block member 82 and has an outer peripheral surface 920 having the same diameter as the outer peripheral surface 60 of the pulley 6A.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to a belt transmission mechanism and a transport robot equipped with the same.

Background Art

[0002] Among transport robots, there are those equipped with a horizontal articulated arm mechanism. As such a transport robot, for example, there is one disclosed in Patent Document 1 below. This transport robot includes an arm rotatably attached to each other and a hand portion rotatably attached to the end of the arm. The arm and the hand portion are rotationally driven by a belt transmission device. In Patent Document 1, a metal steel belt is used as the belt constituting the belt transmission device. The steel belt generates less dust and outgassing than, for example, a rubber timing belt, and a belt transmission device using the steel belt is suitable for being installed in a transport robot arranged in a vacuum environment.

[0003] In the belt transmission device disclosed in Patent Document 1, two steel belts are installed for two pulleys (a driving pulley and a driven pulley). The two steel belts are not endless belts but end belts having both ends. The two steel belts are attached to the two pulleys with different vertical heights (see FIG. 1 of the same document). Also, the two steel belts are attached to the two pulleys with the winding directions opposite to each other (see FIG. 2 of the same document). By attaching the two end belts in this way, the pulley can be rotated in both rotational directions around the axis. Both ends of each steel belt are fastened to the pulley by a press-fit pin, a screw member, etc. in a state along the outer peripheral surface of the pulley. In a belt transmission device configured to fasten both ends of such an end belt to the pulley, the positioning accuracy is better than that of an endless belt, and displacement with respect to the pulley can be suppressed.

[0004] However, in the above-described conventional belt transmission mechanism, it is not allowed for the steel belt (endless belt) to overlap on the outer circumference of the pulley, and there is a limit to the rotation angle of the pulley. Further, regarding the belt wound around the pulley, since it is necessary to avoid interference with the fastening portion at the end of the belt, the rotation angle of the pulley is further restricted.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present disclosure has been conceived under such circumstances, and in a belt transmission mechanism configured to include two steel belts attached to two pulleys with their winding directions opposite to each other, the main problem is to provide a structure capable of expanding the rotation angle of the pulley.

[0007] To solve the above problems, the present disclosure employs the following technical means.

[0008] The belt transmission mechanism provided by the first aspect of the present disclosure includes a first pulley and a second pulley rotatably arranged about a pair of axes parallel to each other, a first end attached to the first pulley, and a second end attached to the second pulley. A first steel belt wound around the first pulley and the second pulley, a third end attached to the first pulley, and a fourth end attached to the second pulley, and being spaced apart from the first steel belt in the axial direction of the first pulley and the second pulley, and wound around the first pulley and the second pulley so as to be opposite to the winding direction of the first steel belt. A second steel belt, a first cover, and a second cover, wherein the first pulley has a first recess and a second recess each recessed from the outer peripheral surface, a first block member is fixed to the first end, and the first block member is disposed in the first recess. The first cover is fixedly disposed in the first recess so as to surround the first block member and has a first outer peripheral surface having the same diameter as the outer peripheral surface of the first pulley. A second block member is fixed to the third end, and the second block member is disposed in the second recess. The second cover is fixedly disposed in the second recess so as to surround the second block member and has a second outer peripheral surface having the same diameter as the outer peripheral surface of the first pulley.

[0009] In a preferred embodiment, a third cover and a fourth cover are further provided. The second pulley has a third recess and a fourth recess each recessed from the outer peripheral surface. A third block member is fixed to the second end, and the third block member is disposed in the third recess. The third cover is fixedly disposed in the third recess so as to surround the third block member and has a third outer peripheral surface having the same diameter as the outer peripheral surface of the second pulley. A fourth block member is fixed to the fourth end, and the fourth block member is disposed in the fourth recess. The fourth cover is fixedly disposed in the fourth recess so as to surround the fourth block member and has a fourth outer peripheral surface having the same diameter as the outer peripheral surface of the second pulley.

[0010] In a preferred embodiment, at least one of the first cover and the second cover is provided with a belt tension adjustment portion capable of pressing the corresponding first block member or second block member toward the circumferential direction of the first pulley.

[0011] In a preferred embodiment, the first recess has a first guide surface that abuts against the first steel belt and smoothly connects to the outer peripheral surface of the first pulley, and the second recess has a second guide surface that abuts against the second steel belt and smoothly connects to the outer peripheral surface of the first pulley.

[0012] The transfer robot provided by the second aspect of the present disclosure includes a belt transmission mechanism provided by the first aspect of the present disclosure, and a horizontal articulated arm mechanism having an arm rotated by the belt transmission mechanism.

Advantages of the Invention

[0013] According to the belt transmission mechanism according to the present disclosure, the first steel belt can be wound approximately one turn (about 360°) in the circumferential direction of the first pulley across the outer peripheral surface of the first pulley and the first outer peripheral surface of the first cover. Further, the second steel belt can be wound approximately one turn (about 360°) in the circumferential direction of the first pulley across the outer peripheral surface of the first pulley and the second outer peripheral surface of the second cover. Therefore, the rotation angle of the first pulley can be enlarged.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying out the Invention

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

[0016] Terms such as "first" and "second" in the present disclosure are merely used as labels and are not necessarily intended to assign an order to those objects.

[0017] FIGS. 1 to 7 show an example of a transport robot provided with a belt transmission mechanism according to the present disclosure. The transport robot A1 of the present embodiment is for transporting a thin plate-shaped workpiece (not shown) such as a circular silicon wafer. The transport robot A1 includes a support 1, a first arm 2, a second arm 3, a hand 4, first pulleys 6A, 6C, 6E, second pulleys 6B, 6D, 6F, a first steel belt 71, a second steel belt 72, a first block member 81, a second block member 82, a third block member 83, a fourth block member 84, a first cover 91, a second cover 92, a third cover 93, and a fourth cover 94.

[0018] The support 1 is supported by a moving mechanism (not shown) and is movable in a predetermined direction within a vertical plane. The configuration of the moving mechanism is not particularly limited, and examples include a vertical articulated arm mechanism and a configuration including a slider unit that can linearly move in the horizontal direction.

[0019] As shown in Fig. 2, the first arm 2 and the second arm 3 are supported by the support 1 and are horizontal articulated arm mechanisms that move along the horizontal plane. The base end portion (the right end portion in Fig. 2) of the first arm 2 is rotatably supported around a first axis O1 that extends in the vertical direction with respect to the support 1. An opening is formed in the lower wall at the base end portion of the first arm 2, and a cylindrical rotating shaft 50 that extends downward from around this opening is connected to the first arm 2. Although detailed illustration description is omitted, a drive source (such as a motor) for rotating the first arm 2 is arranged inside the support 1, and the first arm 2 is rotated around the first axis O1 via the rotating shaft 50 by the drive of the drive source. Further, a rotating shaft 51 and a rotating shaft 52 that extend upward from the support 1 side are inserted through the opening in the lower wall. The rotating shaft 52 is externally fitted to the rotating shaft 51. A bearing (not shown) is interposed between the rotating shaft 51 and the rotating shaft 52. The rotating shaft 51 and the rotating shaft 52 are rotatable around the first axis O1.

[0020] An opening is formed in the upper wall at the tip end portion (the left end portion in Fig. 2) of the first arm 2. Further, a fixed shaft 53 is provided in the lower wall at the tip end portion of the first arm 2. The fixed shaft 53 has a second axis O2 that extends in the vertical direction as a central axis, passes through the opening in the upper wall, and extends upward.

[0021] The second arm 3 is supported by the first arm 2. An opening is formed in the lower wall at the base end portion (the right end portion in FIG. 2) of the second arm 3, and a cylindrical rotating shaft 54 extending downward from around the opening is connected to the second arm 3. The rotating shaft 54 is externally fitted to the rotating shaft 55, and the rotating shaft 55 is externally fitted to the fixed shaft 53. Bearings (not shown) are interposed between the fixed shaft 53 and the rotating shaft 55, and between the rotating shaft 55 and the rotating shaft 54, respectively. Thereby, the rotating shaft 54 is rotatable around the second axis O2. With such a configuration, the second arm 3 is rotatably supported around the second axis O2 extending in the vertical direction with respect to the tip end portion (the left end portion in FIG. 2) of the first arm 2. Note that the fixed shaft 53 provided at the tip end portion of the first arm 2 passes through the opening in the lower wall of the second arm 3 and extends to the inside of the second arm 3.

[0022] An opening is formed in the upper wall at the tip end portion (the left end portion in FIG. 2) of the second arm 3. Further, a fixed shaft 56 is provided in the lower wall at the tip end portion of the second arm 3. The fixed shaft 56 has the third axis O3 extending in the vertical direction as the central axis, passes through the opening in the upper wall, and extends upward.

[0023] As shown in FIG. 1 and the like, the hand 4 has a bifurcated fork-shaped tip and is supported by the second arm 3 in a horizontal posture. The hand 4 is for placing and holding a thin plate-like workpiece (not shown) of a predetermined size, such as a circular silicon wafer. As shown in FIG. 2, a rotating shaft 57 extending downward is connected to the base end portion (the right end portion in FIG. 2) of the hand 4. The rotating shaft 57 is externally fitted to the fixed shaft 56 provided at the tip end portion of the second arm 3, and a bearing (not shown) is interposed between the fixed shaft 56 and the rotating shaft 57. With such a configuration, the hand 4 is rotatably supported around the third axis O3 extending in the vertical direction with respect to the tip end portion of the second arm 3.

[0024] The first pulleys 6A, 6C, 6E, the second pulleys 6B, 6D, 6F, the first steel belt 71, and the second steel belt 72 rotationally drive the second arm 3 (rotation axis 54) and the hand 4 (rotation axis 57). Although details will be described later, the first steel belt 71 and the second steel belt 72 are each made of a thin metal strip and are attached to the first pulleys 6A (6C, 6E) and the second pulleys 6B (6D, 6F). Also, the first block member 81 and the third block member 83 are attached to the first steel belt 71, and the second block member 82 and the fourth block member 84 are attached to the second steel belt 72 (see FIG. 3). The first cover 91 and the second cover 92 are attached to the first pulleys 6A (6C, 6E), and the third cover 93 and the fourth cover 94 are attached to the second pulleys 6B (6D, 6F). The first pulleys 6A, 6C, 6E, the second pulleys 6B, 6D, 6F, the first steel belt 71, the second steel belt 72, the first block member 81, the second block member 82, the third block member 83, the fourth block member 84, the first cover 91, the second cover 92, the third cover 93, and the fourth cover 94 constitute the belt transmission mechanism of the present disclosure.

[0025] As shown in Fig. 2, the first pulley 6A is connected to the upper end of the rotating shaft 51 and is rotatable about the first axis O1. The second pulley 6B is connected to the lower end of the rotating shaft 54 and is externally fitted to the rotating shaft 55, and is rotatable about the second axis O2. The first steel belt 71 and the second steel belt 72 are endless belts each having both ends. The first steel belt 71 and the second steel belt 72 are wound around the first pulley 6A and the second pulley 6B. The second steel belt 72 is positioned apart from the first steel belt 71 in the axial direction (vertical direction) of the first pulley 6A and the second pulley 6B. In the illustrated example, the second steel belt 72 is positioned below the first steel belt 71. Further, as shown in Fig. 3, the second steel belt 72 is wound around the first pulley 6A and the second pulley 6B so as to be opposite to the winding direction of the first steel belt 71. In Fig. 3, the second steel belt 72 is represented by a dotted line for distinction from the first steel belt 71. When the rotating shaft 51 is rotated, the first pulley 6A and the second pulley 6B that is linked to the first pulley 6A via the first steel belt 71 and the second steel belt 72 rotate. Then, the second arm 3 connected to the second pulley 6B via the rotating shaft 54 rotates around the second axis O2.

[0026] As shown in Fig. 2, the first pulley 6C is connected to the upper end of the rotating shaft 52 and is rotatable about the first axis O1. The second pulley 6D is connected to the lower end of the rotating shaft 55 and is externally fitted to the fixed shaft 53, and is rotatable about the second axis O2. The first steel belt 71 and the second steel belt 72 are wound around the first pulley 6C and the second pulley 6D in the same manner as the first pulley 6A and the second pulley 6B.

[0027] The first pulley 6E is connected to the upper end of the rotating shaft 55 and is externally fitted to the fixed shaft 53, and is rotatable about the second axis O2. The second pulley 6F has the lower end of the rotating shaft 57 connected thereto and is externally fitted to the fixed shaft 56, and is rotatable about the third axis O3. The first steel belt 71 and the second steel belt 72 are wound around the first pulley 6E and the second pulley 6F in the same manner as the first pulley 6A and the second pulley 6B. When the rotating shaft 52 is rotated, the first pulley 6C and the second pulley 6D that is linked to the first pulley 6C via the first steel belt 71 and the second steel belt 72 rotate. Further, when the second pulley 6D rotates, the first pulley 6E connected to the second pulley 6D via the rotating shaft 55 and the second pulley 6F that is linked to the first pulley 6E via the first steel belt 71 and the second steel belt 72 rotate. Then, the hand 4 connected to the second pulley 6F via the rotating shaft 57 rotates around the third axis O3.

[0028] Next, with reference to FIGS. 4 to 7, the first pulley 6A, the second pulley 6B, the first steel belt 71, the second steel belt 72, the first block member 81, the second block member 82, the third block member 83, the fourth block member 84, the first cover 91, the second cover 92, the third cover 93, and the fourth cover 94 will be specifically described.

[0029] As shown in FIG. 4, the first pulley 6A has a first recess 61. The first recess 61 is recessed from the outer peripheral surface 60 and the upper surface of the first pulley 6A, and has a first surface 611 and a first guide surface 612. The first surface 611 is a flat surface with which the contact surface 911 of the first cover 91 described later makes surface contact. The first guide surface 612 is a convex curved surface that smoothly connects to both the outer peripheral surface 60 and the first surface 611 of the first pulley 6A.

[0030] The first block member 81 is fixed to the first end portion 711, which is one end of the first steel belt 71, by appropriate means such as welding. A pair of through holes 811 are formed in the first block member 81. In the first end portion 711, through holes are formed in a region corresponding to the pair of through holes 811. The through holes 811 are elongated holes having the left-right direction in FIG. 4 as the longitudinal direction. Threaded holes are formed in the first surface 611 of the first pulley 6A, and mounting bolts 86 are tightened into the threaded holes through the through holes 811. Thereby, the first block member 81 is fixed to the first pulley 6A. The first steel belt 71 wound around the first pulley 6A abuts against the outer peripheral surface 60, the first guide surface 612, and the first surface 611.

[0031] The first cover 91 is disposed in the first recess 61 and has a first outer peripheral surface 910, a contact surface 911, a retracted surface 912, a recess 913, and working holes 914 and 915. The contact surface 911 is in surface contact with the first surface 611 of the first pulley 6A. The retracted surface 912 is a surface that is retracted slightly above the contact surface 911 in FIG. 4. The dimension by which the retracted surface 912 is retracted from the contact surface 911 is slightly larger than the thickness of the first steel belt 71. As a result, the portion of the first steel belt 71 located between the first surface 611 to the first guide surface 612 and the retracted surface 912 is slightly separated from the retracted surface 912. The recess 913 is a portion recessed upward in FIG. 4 from the contact surface 911, and the first block member 81 is accommodated in the recess 913. The working hole 914 is a through hole that communicates from the first outer peripheral surface 910 to the recess 913 and is for operating the mounting bolt 86 from the outside with a tool. The working hole 915 is for operating the adjustment screw 97 attached to the screw hole of the first cover 91 from the outside. When the adjustment screw 97 is tightened, the first block member 81 is pressed in the circumferential direction of the first pulley 6A (the right side in FIG. 4), and the tension of the first steel belt 71 increases. By operating the adjustment screw 97 in this way, the tension of the first steel belt 71 can be adjusted. The working hole 915 and the adjustment screw 97 are an example of the belt tension adjustment portion of the present disclosure. In the first recess 61 of the first pulley 6A, a screw hole extending in a direction orthogonal to the plane of FIG. 4 is formed, and the mounting bolt 96 is tightened into the screw hole. Thereby, the first cover 91 is fixed to the first pulley 6A so as to surround the first block member 81.

[0032] The first outer peripheral surface 910 of the first cover 91 has the same diameter as the outer peripheral surface 60 of the first pulley 6A. Here, "the first outer peripheral surface 910 has the same diameter as the outer peripheral surface 60" means that the first outer peripheral surface 910 is an arc shape having the same radius of curvature as the radius of the outer peripheral surface 60. In a state where the first cover 91 is fixed to the first pulley 6A, the center of the radius of curvature of the first outer peripheral surface 910 coincides with the center of the outer peripheral surface 60, and the outer peripheral surface 60 and the first outer peripheral surface 910 form a series of circumferential shapes with the same diameter. Although the first outer peripheral surface 910 and the outer peripheral surface 60 are designed to have the same diameter, in a state where the first cover 91 is actually fixed to the first pulley 6A, some errors may occur.

[0033] As shown in FIG. 5, the first pulley 6A has a second recess 62. The second recess 62 is recessed from the outer peripheral surface 60 and the lower surface of the first pulley 6A, and has a second surface 621 and a second guide surface 622. The second surface 621 is a flat surface with which the contact surface 921 of the second cover 92 described later makes surface contact. The second guide surface 622 is a convex curved surface that smoothly connects to both the outer peripheral surface 60 and the second surface 621 of the first pulley 6A.

[0034] The second block member 82 is fixed to the third end portion 721, which is one end of the second steel belt 72, by an appropriate means such as welding. A pair of through holes 821 are formed in the second block member 82. In the third end portion 721, through holes are formed in a region corresponding to the pair of through holes 821. The through hole 821 is a long hole having the vertical direction in FIG. 5 as the longitudinal direction. A screw hole is formed in the second surface 621 of the first pulley 6A, and a mounting bolt 86 is tightened into the screw hole through the through hole 821. Thereby, the second block member 82 is fixed to the first pulley 6A. The second steel belt 72 wound around the first pulley 6A abuts against the outer peripheral surface 60, the second guide surface 622, and the second surface 621.

[0035] The second cover 92 is disposed in the second recess 62 and has a second outer peripheral surface 920, a contact surface 921, a retreat surface 922, a recess 923, and working holes 924 and 925. The contact surface 921 is in surface contact with the second surface 621 of the first pulley 6A. The retreat surface 922 is a surface that retreats slightly to the right side of FIG. 5 from the contact surface 921. The dimension by which the retreat surface 922 retreats from the contact surface 921 is slightly larger than the thickness of the second steel belt 72. Thereby, the portion of the second steel belt 72 located between the second surface 621 to the second guide surface 622 and the retreat surface 922 is slightly separated from the retreat surface 922. The recess 923 is a portion recessed to the right side in FIG. 5 from the contact surface 921, and the second block member 82 is accommodated in the recess 923. The working hole 924 is a through hole that communicates from the second outer peripheral surface 920 to the recess 923 and is for operating the mounting bolt 86 from the outside with a tool. The working hole 925 is for operating the adjustment screw 97 attached to the screw hole of the second cover 92 from the outside. When the adjustment screw 97 is tightened, the second block member 82 is pressed in the circumferential direction (upper side in FIG. 5) of the first pulley 6A, and the tension of the second steel belt 72 increases. By operating the adjustment screw 97 in this way, the tension of the second steel belt 72 can be adjusted. The working hole 925 and the adjustment screw 97 are an example of the belt tension adjustment portion of the present disclosure. A screw hole extending in a direction perpendicular to the plane of FIG. 5 is formed in the second recess 62 of the first pulley 6A, and the mounting bolt 96 is tightened into the screw hole. Thereby, the second cover 92 is fixed to the first pulley 6A so as to surround the second block member 82.

[0036] The second outer peripheral surface 920 of the second cover 92 has the same diameter as the outer peripheral surface 60 of the first pulley 6A. Here, "the second outer peripheral surface 920 has the same diameter as the outer peripheral surface 60" means that the second outer peripheral surface 920 is an arc shape having the same radius of curvature as the radius of the outer peripheral surface 60. In a state where the second cover 92 is fixed to the first pulley 6A, the center of the radius of curvature of the second outer peripheral surface 920 coincides with the center of the outer peripheral surface 60, and the outer peripheral surface 60 and the second outer peripheral surface 920 form a series of circumferential shapes with the same diameter. Although the second outer peripheral surface 920 and the outer peripheral surface 60 are designed to have the same diameter, in a state where the second cover 92 is actually fixed to the first pulley 6A, some errors may occur.

[0037] As shown in FIG. 6, the second pulley 6B has a third recess 63. The third recess 63 is recessed from the outer peripheral surface 60 and the upper surface of the second pulley 6B, and has a third surface 631 and a third guide surface 632. The third surface 631 is a plane with which the contact surface 931 of the third cover 93 to be described later makes surface contact. The third guide surface 632 is a convex curved surface that smoothly connects to both the outer peripheral surface 60 and the third surface 631 of the second pulley 6B.

[0038] The third block member 83 is fixed to the second end portion 712, which is the other end of the first steel belt 71, by an appropriate means such as welding. A pair of through holes 831 are formed in the third block member 83. At the second end portion 712, through holes are formed in a region corresponding to the pair of through holes 831. A screw hole is formed in the third surface 631 of the second pulley 6B, and a mounting bolt 86 is tightened into the screw hole through the through hole 831. Thereby, the third block member 83 is fixed to the second pulley 6B. The first steel belt 71 wound around the second pulley 6B abuts against the outer peripheral surface 60, the third guide surface 632, and the third surface 631.

[0039] The third cover 93 is disposed in the third recess 63 and has a third outer peripheral surface 930, a contact surface 931, a retracted surface 932, a recess 933, and a working hole 934. The contact surface 931 is in surface contact with the third surface 631 of the second pulley 6B. The retracted surface 932 is a surface that is retracted slightly to the left in FIG. 6 from the contact surface 931. The dimension by which the retracted surface 932 is retracted from the contact surface 931 is slightly larger than the thickness of the first steel belt 71. Thereby, the portion of the first steel belt 71 located between the third surface 631 to the third guide surface 632 and the retracted surface 932 is slightly separated from the retracted surface 932.

[0040] The recess 933 is a portion recessed to the left in FIG. 6 from the contact surface 931, and the third block member 83 is accommodated in the recess 933. The working hole 934 is a through hole that communicates from the third outer peripheral surface 930 to the recess 933 and is for operating the mounting bolt 86 from the outside with a tool. A threaded hole extending in a direction orthogonal to the plane of FIG. 6 is formed in the third recess 63 of the second pulley 6B, and the mounting bolt 96 is tightened into the threaded hole. Thereby, the third cover 93 is fixed to the second pulley 6B so as to surround the third block member 83.

[0041] The third outer peripheral surface 930 of the third cover 93 has the same diameter as the outer peripheral surface 60 of the second pulley 6B. Here, "the third outer peripheral surface 930 has the same diameter as the outer peripheral surface 60" means that the third outer peripheral surface 930 is arcuate with the same radius of curvature as the radius of the outer peripheral surface 60, and in a state where the third cover 93 is fixed to the second pulley 6B, the center of the radius of curvature of the third outer peripheral surface 930 coincides with the center of the outer peripheral surface 60, and the outer peripheral surface 60 and the third outer peripheral surface 930 form a series of circumferential shapes with the same diameter. Although the third outer peripheral surface 930 and the outer peripheral surface 60 are designed to have the same diameter, in an actual state where the third cover 93 is fixed to the second pulley 6B, some errors may occur.

[0042] As shown in FIG. 7, the second pulley 6B has a fourth recess 64. The fourth recess 64 is recessed from the outer peripheral surface 60 and the lower surface of the second pulley 6B, and has a fourth surface 641 and a fourth guide surface 642. The fourth surface 641 is a flat surface with which the contact surface 941 of the fourth cover 94 described later makes surface contact. The fourth guide surface 642 is a convex curved surface that smoothly connects to both the outer peripheral surface 60 and the fourth surface 641 of the second pulley 6B.

[0043] The fourth block member 84 is fixed to the fourth end portion 722, which is the other end of the second steel belt 72, by appropriate means such as welding. A pair of through holes 841 are formed in the fourth block member 84. In the fourth end portion 722, through holes are formed in regions corresponding to the pair of through holes 841. A screw hole is formed in the fourth surface 641 of the second pulley 6B, and a mounting bolt 86 is tightened into the screw hole through the through hole 841. Thereby, the fourth block member 84 is fixed to the second pulley 6B. The second steel belt 72 wound around the second pulley 6B abuts against the outer peripheral surface 60, the fourth guide surface 642, and the fourth surface 641.

[0044] The fourth cover 94 is disposed in the fourth recess 64 and has a fourth outer peripheral surface 940, a contact surface 941, a retracted surface 942, a recess 943, and a working hole 944. The contact surface 941 is in surface contact with the fourth surface 641 of the second pulley 6B. The retracted surface 942 is a surface that is retracted slightly below the contact surface 941 in FIG. 7. The dimension by which the retracted surface 942 is retracted from the contact surface 941 is slightly larger than the thickness of the second steel belt 72. Thereby, the portion of the second steel belt 72 located between the fourth surface 641 to the fourth guide surface 642 and the retracted surface 942 is slightly separated from the retracted surface 942. The recess 943 is a portion recessed downward in FIG. 7 from the contact surface 941, and the fourth block member 84 is accommodated in the recess 943. The working hole 944 is a through hole that communicates from the fourth outer peripheral surface 940 to the recess 943 and is for operating the mounting bolt 86 from the outside with a tool. A screw hole extending in a direction orthogonal to the plane of FIG. 7 is formed in the fourth recess 64 of the second pulley 6B, and the mounting bolt 96 is tightened into the screw hole. Thereby, the fourth cover 94 is fixed to the second pulley 6B so as to surround the fourth block member 84.

[0045] The fourth outer peripheral surface 940 of the fourth cover 94 has the same diameter as the outer peripheral surface 60 of the second pulley 6B. Here, "the fourth outer peripheral surface 940 has the same diameter as the outer peripheral surface 60" means that the fourth outer peripheral surface 940 is arc-shaped with the same radius of curvature as the radius of the outer peripheral surface 60, and in a state where the fourth cover 94 is fixed to the second pulley 6B, the center of the radius of curvature of the fourth outer peripheral surface 940 coincides with the center of the outer peripheral surface 60, and the outer peripheral surface 60 and the fourth outer peripheral surface 940 form a series of circumferential shapes with the same diameter. In terms of design, the fourth outer peripheral surface 940 and the outer peripheral surface 60 are set to have the same diameter, but in an actual state where the fourth cover 94 is fixed to the second pulley 6B, some errors may occur.

[0046] FIG. 8 is a plan view schematically showing a state in which the first pulley 6A and the second pulley 6B are rotated most in one rotational direction and a state in which they are rotated most in the other rotational direction. In FIG. 8, the second steel belt 72 is represented by a dotted line for distinction from the first steel belt 71.

[0047] As shown in Fig. 8(a), when the first pulley 6A and the second pulley 6B rotate most in one rotational direction, the first steel belt 71 is wound around the outer peripheral surface 60 of the first pulley 6A and the first outer peripheral surface 910 of the first cover 91, and is wound approximately one turn (about 360°) in the circumferential direction of the first pulley 6A. Also, the second steel belt 72 is wound around the outer peripheral surface 60 of the second pulley 6B and the fourth outer peripheral surface 940 of the fourth cover 94, and is wound approximately one turn (about 360°) in the circumferential direction of the second pulley 6B.

[0048] As shown in Fig. 8(b), when the first pulley 6A and the second pulley 6B rotate most in the other rotational direction, the first steel belt 71 is wound around the outer peripheral surface 60 of the second pulley 6B and the third outer peripheral surface 930 of the third cover 93, and is wound approximately one turn (about 360°) in the circumferential direction of the second pulley 6B. Also, the second steel belt 72 is wound around the outer peripheral surface 60 of the first pulley 6A and the second outer peripheral surface 920 of the second cover 92, and is wound approximately one turn (about 360°) in the circumferential direction of the first pulley 6A. As can be understood from this, in this embodiment, the rotation angle of the first pulley 6A and the second pulley 6B is about 360°.

[0049] The structures of the first pulley 6C and the second pulley 6D shown in FIG. 2 are the same as those of the first pulley 6A and the second pulley 6B described above. Also in the first pulley 6C and the second pulley 6D, the first steel belt 71 and the second steel belt 72 are wound around. The attachment structures of the first steel belt 71 and the second steel belt 72 to these first pulley 6C and second pulley 6D are also the same as those of the first pulley 6A and the second pulley 6B described above. The first steel belt 71 and the second steel belt 72 are fixed to the first pulley 6C and the second pulley 6D using the first block member 81 to the fourth block member 84. Also, a first cover 91 and a second cover 92 are attached to the first pulley 6C in the same manner as the first pulley 6A, and a third cover 93 and a fourth cover 94 are attached to the second pulley 6D in the same manner as the second pulley 6B. The rotation angles of the first pulley 6C and the second pulley 6D are approximately 360°, the same as those of the first pulley 6A and the second pulley 6B described above.

[0050] The structures of the first pulley 6E and the second pulley 6F shown in FIG. 2 are the same as those of the first pulley 6A and the second pulley 6B described above. Also in the first pulley 6E and the first pulley 6E, the first steel belt 71 and the second steel belt 72 are wound around. The attachment structures of the first steel belt 71 and the second steel belt 72 to these first pulley 6E and first pulley 6E are also the same as those of the first pulley 6A and the second pulley 6B described above. The first steel belt 71 and the second steel belt 72 are fixed to the first pulley 6E and the second pulley 6F using the first block member 81 to the fourth block member 84. Also, a first cover 91 and a second cover 92 are attached to the first pulley 6E in the same manner as the first pulley 6A, and a third cover 93 and a fourth cover 94 are attached to the second pulley 6F in the same manner as the second pulley 6B. The rotation angles of the first pulley 6E and the second pulley 6F are approximately 360°, the same as those of the first pulley 6A and the second pulley 6B described above.

[0051] Next, the operation of this embodiment will be described.

[0052] In the transfer robot A1, a first steel belt 71 and a second steel belt 72 are wound around a first pulley 6A (6C, 6E) and a second pulley 6B (6D, 6F). The first steel belt 71 and the second steel belt 72 are endless belts each having both ends. The second steel belt 72 is positioned apart from the first steel belt 71 in the axial direction (vertical direction) of the first pulley 6A (6C, 6E) and the second pulley 6B (6D, 6F) with respect to the first steel belt 71. The second steel belt 72 is wound around the first pulley 6A (6C, 6E) and the second pulley 6B (6D, 6F) so as to be opposite to the winding direction of the first steel belt 71.

[0053] The first pulleys 6A (6C, 6E) each have a first recess 61 and a second recess 62 that are recessed from the outer peripheral surface 60. A first block member 81 is fixed to a first end portion 711, which is one end of the first steel belt 71, and the first block member 81 is disposed in the first recess 61. A first cover 91 is fixedly disposed in the first recess 61 so as to surround the first block member 81. The first cover 91 has a first outer peripheral surface 910 having the same diameter as the outer peripheral surface 60 of the first pulley 6A (6C, 6E). A second block member 82 is fixed to a third end portion 721, which is one end of the second steel belt 72, and the second block member 82 is disposed in the second recess 62. A second cover 92 is fixedly disposed in the second recess 62 so as to surround the second block member 82. The second cover 92 has a second outer peripheral surface 920 having the same diameter as the outer peripheral surface 60 of the first pulley 6A (6C, 6E). According to such a configuration, the first steel belt 71 can be wound around the first outer peripheral surface 910 of the first cover 91 fixedly disposed so as to surround the first block member 81 without interfering with the first block member 81, which is the fixing portion of the first steel belt 71 with respect to the first pulley 6A (6C, 6E). Further, the second steel belt 72 can be wound around the second outer peripheral surface 920 of the second cover 92 fixedly disposed so as to surround the second block member 82 without interfering with the second block member 82, which is the fixing portion of the second steel belt 72 with respect to the first pulley 6A (6C, 6E). Thereby, the first steel belt 71 (second steel belt 72) can be wound approximately one turn (about 360°) in the circumferential direction of the first pulley 6A (6C, 6E) across the outer peripheral surface 60 of the first pulley 6A (6C, 6E) and the first outer peripheral surface 910 (second outer peripheral surface 920) of the first cover 91 (second cover 92). Therefore, the rotation angle of the first pulley 6A (6C, 6E) can be enlarged.

[0054] The second pulleys 6B (6D, 6F) each have a third recess 63 and a fourth recess 64 that are recessed from the outer peripheral surface 60. A third block member 83 is fixed to the second end portion 712, which is the other end of the first steel belt 71, and the third block member 83 is disposed in the third recess 63. A third cover 93 is fixedly disposed in the third recess 63 so as to surround the third block member 83. The third cover 93 has a third outer peripheral surface 930 having the same diameter as the outer peripheral surface 60 of the second pulley 6B (6D, 6F). A fourth block member 84 is fixed to the fourth end portion 722, which is the other end of the second steel belt 72, and the fourth block member 84 is disposed in the fourth recess 64. A fourth cover 94 is fixedly disposed in the fourth recess 64 so as to surround the fourth block member 84. The fourth cover 94 has a fourth outer peripheral surface 940 having the same diameter as the outer peripheral surface 60 of the second pulley 6B (6D, 6F). According to such a configuration, the first steel belt 71 can be wound around the third outer peripheral surface 930 of the third cover 93 fixedly disposed so as to surround the third block member 83 without interfering with the third block member 83, which is the fixing portion of the first steel belt 71 with respect to the second pulley 6B (6D, 6F). Further, the second steel belt 72 can be wound around the fourth outer peripheral surface 940 of the fourth cover 94 fixedly disposed so as to surround the fourth block member 84 without interfering with the fourth block member 84, which is the fixing portion of the second steel belt 72 with respect to the second pulley 6B (6D, 6F). Thereby, the first steel belt 71 (second steel belt 72) can be wound approximately once (about 360°) in the circumferential direction of the second pulley 6B (6D, 6F) across the outer peripheral surface 60 of the second pulley 6B (6D, 6F) and the third outer peripheral surface 930 (fourth outer peripheral surface 940) of the third cover 93 (fourth cover 94). Also, as described above, the first steel belt 71 (second steel belt 72) can be wound approximately once (about 360°) in the circumferential direction of the first pulley 6A across the outer peripheral surface 60 of the first pulley 6A (6C, 6E) and the first outer peripheral surface 910 (second outer peripheral surface 920) of the first cover 91 (second cover 92). Thereby, the rotation angles of the first pulley 6A and the second pulley 6B become approximately 360°.In the conventional configuration (the configuration shown in FIG. 3 of JP-A-2008-223974), the rotation angle of the pulley is, for example, about 300°. In the present embodiment, it is possible to increase the rotation angles of the first pulleys 6A (6C, 6E) and the second pulleys 6B (6D, 6F).

[0055] The first cover 91 is provided with an adjusting screw 97 (belt tension adjusting portion) capable of pressing the first block member 81 in the circumferential direction of the first pulley 6A (6C, 6E). The second cover 92 is provided with an adjusting screw 97 (belt tension adjusting portion) capable of pressing the second block member 82 in the circumferential direction of the first pulley 6A (6C, 6E). According to such a configuration, as shown in FIG. 2, even when a plurality of first pulleys 6A and 6C are arranged side by side in the direction of the first axis O1, for example, the adjusting screw 97 can be easily operated from the outside, and the tensions of the first steel belt 71 and the second steel belt 72 can be easily adjusted. Note that, unlike the present embodiment, the adjusting screw 97 may be provided only on one of the first cover 91 and the second cover 92. Even in this case, by operating the adjusting screw 97, it is possible to adjust the tensions of the first steel belt 71 and the second steel belt 72 attached with their winding directions opposite to each other.

[0056] The first recess 61 of the first pulley 6A (6C, 6E) has a first guide surface 612. The first guide surface 612 smoothly connects to the outer peripheral surface 60 of the first pulley 6A and abuts against the first steel belt 71. Further, the second recess 62 of the first pulley 6A (6C, 6E) has a second guide surface 622. The second guide surface 622 smoothly connects to the outer peripheral surface 60 of the first pulley 6A and abuts against the second steel belt 72. According to such a configuration, it is possible to prevent an uneven load from occurring on the first steel belt 71 and the second steel belt 72 wound around the first pulley 6A (6C, 6E), and the first pulley 6A (6C, 6E) can be rotated smoothly. In the present embodiment, also in the second pulley 6B (6D, 6F), third guide surfaces 632 and fourth guide surfaces 642 similar to the first guide surface 612 and the second guide surface 622 of the first pulley 6A (6C, 6E) are formed. Thereby, it is possible to prevent an uneven load from occurring on the first steel belt 71 and the second steel belt 72 wound around the second pulley 6B (6D, 6F), and the second pulley 6B (6D, 6F) can be rotated smoothly.

[0057] The belt conduction mechanism according to the present disclosure is not limited to the above-described embodiments. The specific configuration of the conveying device according to the present disclosure can be freely designed in various ways.

Description of Reference Numerals

[0058] A1: Transfer robot, 2: First arm, 3: Second arm, 6A, 6C, 6E: First pulley, 6B, 6D, 6F: Second pulley, 60: Outer peripheral surface, 61: First recess, 612: First guide surface, 62: Second recess, 622: Second guide surface, 63: Third recess, 64: Fourth recess, 71: First steel belt, 711: First end, 712: Second end, 72: Second steel belt, 721: Third end, 722: Fourth end, 81: First block member, 82: Second block member, 83: Third block member, 84: Fourth block member, 91: First cover, 910: First outer peripheral surface, 92: Second cover, 920: Second outer peripheral surface, 93: Third cover, 930: Third outer peripheral surface, 94: Fourth cover, 940: Fourth outer peripheral surface, 97: Adjusting screw (belt tension adjusting part), O1: First axis, O2: Second axis, O3: Third axis

Claims

1. A first pulley and a second pulley rotatably arranged about a pair of mutually parallel axes respectively, a first end attached to the first pulley and a second end attached to the second pulley, and a first steel belt wound around the first pulley and the second pulley, a third end attached to the first pulley and a fourth end attached to the second pulley, and a second steel belt wound around the first pulley and the second pulley so as to be spaced apart in the axial direction of the first pulley and the second pulley with respect to the first steel belt and opposite to the winding direction of the first steel belt, a first cover, a second cover, and the first pulley has a first recess and a second recess each recessed from the outer peripheral surface, a first block member is fixed to the first end, and the first block member is disposed in the first recess, the first cover is fixedly disposed in the first recess so as to surround the first block member and has a first outer peripheral surface having the same diameter as the outer peripheral surface of the first pulley, a second block member is fixed to the third end, and the second block member is disposed in the second recess, the second cover is fixedly disposed in the second recess so as to surround the second block member and has a second outer peripheral surface having the same diameter as the outer peripheral surface of the first pulley, a belt transmission mechanism.

2. further comprising a third cover and a fourth cover, the second pulley has a third recess and a fourth recess each recessed from the outer peripheral surface, a third block member is fixed to the second end, and the third block member is disposed in the third recess, the third cover is fixedly disposed in the third recess so as to surround the third block member and has a third outer peripheral surface having the same diameter as the outer peripheral surface of the second pulley, a fourth block member is fixed to the fourth end, and the fourth block member is disposed in the fourth recess, the fourth cover is fixedly disposed in the fourth recess so as to surround the fourth block member and has a fourth outer peripheral surface having the same diameter as the outer peripheral surface of the second pulley, the belt transmission mechanism according to claim 1.

3. The belt drive mechanism according to claim 1, wherein at least one of the first cover and the second cover is provided with a belt tension adjustment portion capable of pressing the corresponding first block member or the second block member toward the circumferential direction of the first pulley.

4. The first recess has a first guide surface that abuts on the first steel belt and smoothly connects to the outer peripheral surface of the first pulley. The belt drive mechanism according to claim 1, wherein the second recess has a second guide surface that abuts on the second steel belt and smoothly connects to the outer peripheral surface of the first pulley.

5. A transfer robot comprising the belt drive mechanism according to any one of claims 1 to 4, and a horizontal articulated arm mechanism having an arm rotated by the belt drive mechanism.

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