Industrial robot

Abstract

SOLUTION: This industrial robot comprises: a hollow speed reducer 21 arranged in a joint part; and a speed reduction mechanism 22 for reducing, in speed, and transmitting, to the hollow speed reducer 21, rotation of a motor. An input shaft 23 of the hollow speed reducer 21 is housed in a case 25 of the hollow speed reducer 21, and a part of the fixed shaft 27 disposed at the center in the radial direction of the hollow speed reducer 21 is disposed on the inner peripheral side of the input shaft 23. The input-use rotary shaft 30 of the speed reduction mechanism 22 includes a held portion 30c rotatably held by the case body 25, and is coupled to the input-use shaft 23 inside the case body 25, as well as, coupled to the motor outside the case body 25. In order to prevent leakage of lubricant from inside the case body 25, a seal member 32 is disposed on an outer peripheral side of the held portion 30c, and an inner peripheral surface of the seal member 32 is in contact with an outer peripheral surface of the held portion 30c. An outer diameter of the held portion 30c is smaller than an outer diameter of the fixed shaft 27.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an industrial robot. [Background technology]

[0002] Conventionally, an industrial robot for transporting glass substrates in a vacuum has been known (see, for example, Patent Document 1). The industrial robot described in Patent Document 1 includes two hands on which substrates are placed, an arm to which the two hands are connected, a swing arm to which the arms are connected, and a main body to which the swing arm is connected. The arm includes two tip-side arms to which the tips of the two hands are rotatably connected, and a common arm to which the base ends of the two tip-side arm sections are rotatably connected and which is also rotatably connected to the tip side of the swing arm.

[0003] The industrial robot described in Patent Document 1 includes a first drive mechanism and a second drive mechanism that rotate the tip-side arm relative to the common arm and rotate the hand relative to the tip-side arm, and a third drive mechanism that rotates the common arm relative to the swing arm. The third drive mechanism includes a motor and a reducer connected to the motor. The reducer is disposed at a joint that is the connection between the swing arm and the common arm. The reducer is a hollow wave gear device. In other words, the reducer is a hollow reducer. The input shaft of the reducer is hollow and disposed at the radial center of the reducer.

[0004] In the industrial robot described in Patent Document 1, the input shaft of the reducer is rotatably held in a case body of the reducer. A pulley located outside the case body is fixed to one end of the input shaft. Grease is contained inside the case body as a lubricant. An annular seal member is arranged on the outer periphery of the input shaft to prevent the grease from leaking from inside the case body. The inner periphery of the seal member is in contact with the outer periphery of the input shaft with a predetermined contact pressure. A cylindrical fixed shaft is arranged on the inner periphery of the input shaft. Wiring and the like drawn from the first drive mechanism and the second drive mechanism are arranged on the inner periphery of the fixed shaft. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2023-54398 Summary of the Invention [Problem to be solved by the invention]

[0006] In the industrial robot described in Patent Document 1, the reducer disposed in the joint has wiring and other components disposed on the inner periphery of the fixed shaft, which tends to increase the outer diameter of the fixed shaft. Therefore, in this industrial robot, the outer diameter of the input shaft, which is disposed on the inner periphery of the fixed shaft, also tends to increase. As the outer diameter of the input shaft increases, even if the rotational speed of the input shaft is constant, the speed (circumferential speed) of the outer periphery of the input shaft increases, making it more likely for heat to be generated between the outer periphery of the input shaft and the inner periphery of the seal member. Heat generation between the outer periphery of the input shaft and the inner periphery of the seal member may increase the temperature of the grease contained in the case, resulting in a decrease in the viscosity of the grease. Therefore, in the case of the industrial robot described in Patent Document 1, for example, when the industrial robot is used under harsh operating conditions, the viscosity of the grease contained in the case may decrease, potentially causing the grease to leak from inside the case member.

[0007] Therefore, the object of the present invention is to provide an industrial robot in which a hollow reducer is arranged in a joint, and which is capable of suppressing leakage of lubricant from inside the case body of the hollow reducer, even when the industrial robot is used under harsh operating conditions, for example. [Means for solving the problem]

[0008] In order to solve the above problems, one aspect of the present invention provides an industrial robot having a joint, the industrial robot comprising a motor, a hollow reducer disposed in the joint, and a reduction mechanism for reducing the rotation of the motor and transmitting the reduced rotation to the hollow reducer, the hollow reducer comprising an input shaft formed in a hollow shape, a case body for rotatably holding the input shaft, and a cylindrical fixed shaft fixed to the case body and disposed at the radial center of the hollow reducer, the reduction mechanism comprising an input rotating shaft connected to the input shaft and the motor, and a reduction mechanism for preventing leakage of lubricant from inside the case body. the input shaft is disposed inside the case body, a part of the fixed shaft is disposed on the inner peripheral side of the input shaft, the input rotating shaft has a held portion rotatably held in the case body, is connected to the input shaft inside the case body and is connected to the motor outside the case body, the axis of the input shaft and the axis of the input rotating shaft are disposed at positions offset from each other, the seal member is disposed on the outer peripheral side of the held portion, the inner peripheral surface of the seal member contacts the outer peripheral surface of the held portion, and the outer diameter of the held portion is smaller than the outer diameter of the fixed shaft.

[0009] In the industrial robot of this aspect, the reduction mechanism for reducing the rotation of the motor and transmitting it to the hollow reducer includes an input rotating shaft connected to the input shaft of the hollow reducer and the motor, and the axes of the input shaft and the input rotating shaft are offset from each other. Also, in this aspect, the input shaft is disposed inside the case body, and the input rotating shaft is connected to the input shaft inside the case body and to the motor outside the case body. Furthermore, in this aspect, the outer diameter of the held portion of the input rotating shaft, which comes into contact with the inner circumferential surface of the seal member for preventing leakage of lubricant from inside the case body, is smaller than the outer diameter of the fixed shaft.

[0010] Therefore, in this aspect, even if the outer diameters of the cylindrical fixed shaft, which is disposed on the inner periphery of the input shaft, are large because wiring or the like is disposed on the inner periphery of the cylindrical fixed shaft, the outer diameter of the held portion of the rotating input shaft can be reduced. Therefore, in this aspect, the speed (circumferential speed) of the outer periphery of the held portion that contacts the inner periphery of the seal member can be slowed. As a result, in this aspect, heat generation between the outer periphery of the held portion of the rotating input shaft and the inner periphery of the seal member can be suppressed. Therefore, in this aspect, even when an industrial robot is used under harsh operating conditions, for example, a decrease in the viscosity of the lubricant contained in the case body can be suppressed, thereby suppressing leakage of the lubricant from inside the case body.

[0011] In addition, in this aspect, the speed reduction mechanism reduces the rotational speed of the motor before transmitting it to the hollow reducer, thereby lowering the rotational speed of the input shaft rotating inside the case body. Therefore, in this aspect, heat generation inside the case body can be suppressed. As a result, in this aspect, even when the industrial robot is used under harsh operating conditions, a decrease in the viscosity of the lubricant contained in the case body can be effectively suppressed, and leakage of the lubricant from inside the case body can be effectively suppressed. [Effects of the Invention]

[0012] As described above, in one aspect of the present invention, in an industrial robot in which a hollow reducer is arranged in a joint, it is possible to suppress leakage of lubricant from inside the case body of the hollow reducer, even if the industrial robot is used under harsh operating conditions, for example. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view of an industrial robot according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view of the industrial robot shown in FIG. [Figure 3]FIG. 3 is a cross-sectional view for explaining the internal configuration of the base end portion of the arm and the swing arm shown in FIG. [Figure 4] FIG. 4 is an enlarged view of part E in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] (Configuration of industrial robots) Fig. 1 is a plan view of an industrial robot 2 according to an embodiment of the present invention, and Fig. 2 is a side view of the industrial robot 2 shown in Fig. 1.

[0016] The industrial robot 2 (hereinafter referred to as "robot 2") of this embodiment is a robot for transporting objects to be transported, such as glass substrates 3 for organic EL (organic electroluminescence) displays and glass substrates 3 for liquid crystal displays (hereinafter referred to as "substrates 3"). The robot 2 is a horizontal articulated robot incorporated into a display manufacturing system for use. The robot 2 transports the substrates 3 in a vacuum.

[0017] The robot 2 comprises hands 4, 5 on which the substrate 3 is mounted, an arm 6 to which the hands 4, 5 are connected, a swing arm 7 to which the arm 6 is connected, and a main body 8 to which the swing arm 7 is connected. The robot 2 in this embodiment comprises two hands 4, 5. The hands 4, 5 are rotatably connected to the tip end of the arm 6. The base end side of the arm 6 is rotatably connected to the tip end side of the swing arm 7. The base end side of the swing arm 7 is rotatably connected to the main body 8. The swing arm 7 in this embodiment is an arm support part to which the base end side of the arm 6 is rotatably connected.

[0018] The arm 6 includes two tip-side arms 10, 11 to which the two hands 4, 5 are rotatably connected at their tip ends, and a common arm 12 to which the base ends of the two tip-side arms 10, 11 are rotatably connected and which is also rotatably connected to the tip end of the swing arm 7. The arm 6 in this embodiment is composed of the two tip-side arms 10, 11 and one common arm 12. The hand 4 is rotatably connected to the tip end of the tip-side arm 10. The hand 5 is rotatably connected to the tip end of the tip-side arm 11.

[0019] The hand 4 is rotatable relative to the tip-side arm portion 10 with the vertical direction as the axis of rotation. The hand 5 is rotatable relative to the tip-side arm portion 11 with the vertical direction as the axis of rotation. The tip-side arms 10, 11 are rotatable relative to the common arm portion 12 with the vertical direction as the axis of rotation. The common arm portion 12 is rotatable relative to the swing arm 7 with the vertical direction as the axis of rotation. The swing arm 7 is rotatable relative to the main body portion 8 with the vertical direction as the axis of rotation.

[0020] The hand 4 is arranged above the hand 5. The tip side arm portion 10 is arranged above the hand 4. The tip side arm portion 11 is arranged below the hand 5. The common arm portion 12 is arranged below the tip side arm portion 11. The common arm portion 12 is arranged above the swing arm 7. The swing arm 7 is arranged above the main body portion 8.

[0021] The main body 8 includes a case body 13 formed in a cylindrical shape with a bottom, and a lid body 14 that covers the opening at the top end of the case body 13. The outer diameter of the lid body 14 is larger than the outer diameter of the case body 13. The outer peripheral portion of the lid body 14 forms a flange 14b that extends radially outward from the case body 13. In this embodiment, the portion of the robot 2 above the lower surface of the flange 14b is disposed in a vacuum chamber, and the hands 4, 5, arm 6, and swing arm 7 are disposed in a vacuum region VR (in a vacuum). Meanwhile, the portion of the robot 2 below the lower surface of the flange 14b is disposed in an atmospheric region AR (in the atmosphere).

[0022] The tip-side arms 10, 11 are formed in a block shape that has an elongated oval shape when viewed from the top-bottom direction and is relatively thin in thickness in the top-bottom direction. The common arm 12 is formed in a generally V-shaped block shape. A central portion (vertex portion) of the generally V-shaped common arm 12 is rotatably connected to the tip side of the swing arm 7. The base end side of the tip-side arm 10 is rotatably connected to one tip side of the generally V-shaped common arm 12, and the base end side of the tip-side arm 11 is rotatably connected to the other tip side of the common arm 12. The swing arm 7 is formed in a block shape that has an elongated rectangular shape when viewed from the top-bottom direction and is relatively thin in thickness in the top-bottom direction.

[0023] The tip-side arm portions 10, 11 and the common arm portion 12 are formed to be hollow. That is, the arm 6 is formed to be hollow. Also, the swing arm 7 is formed to be hollow. The inside of the tip-side arm portions 10, 11, which are formed to be hollow, is a vacuum. On the other hand, the inside of the hollow common arm portion 12 and the swing arm 7 is at atmospheric pressure. Also, the inside of the main body portion 8 is at atmospheric pressure.

[0024] In the horizontal direction, the distance between the rotation center of the common arm section 12 with respect to the swing arm 7 and the rotation center of the tip-side arm section 10 with respect to the common arm section 12 is equal to the distance between the rotation center of the tip-side arm section 10 with respect to the common arm section 12 and the rotation center of the hand 4 with respect to the tip-side arm section 10, and the distance between the rotation center of the common arm section 12 with respect to the swing arm 7 and the rotation center of the tip-side arm section 11 with respect to the common arm section 12 is equal to the distance between the rotation center of the tip-side arm section 11 with respect to the common arm section 12 and the rotation center of the hand 5 with respect to the tip-side arm section 11. Furthermore, in the horizontal direction, the distance between the rotation center of the common arm section 12 with respect to the swing arm 7 and the rotation center of the tip-side arm section 10 with respect to the common arm section 12 is equal to the distance between the rotation center of the common arm section 12 with respect to the swing arm 7 and the rotation center of the tip-side arm section 11 with respect to the common arm section 12.

[0025] The arm 6 is extendable relative to the swing arm 7 between a position where the tips of the hands 4, 5 extend away from a joint 16, which is a connection between the swing arm 7 and the common arm unit 12 (i.e., a connection between the arm 6 and the swing arm 7), and a position where the tips of the hands 4, 5 retract so as to approach the joint 16. In this embodiment, when the part of the arm 6 on the tip-side arm unit 10 side extends so that the tip of the hand 4 moves away from the joint 16, the part of the arm 6 on the tip-side arm unit 11 side retracts, and when the part of the arm 6 on the tip-side arm unit 11 side extends so that the tip of the hand 5 moves away from the joint 16, the part of the arm 6 on the tip-side arm unit 10 side retracts. When the arm 6 retracts or expands relative to the swing arm 7, the hands 4, 5 move linearly in the horizontal direction while facing in a fixed direction relative to the swing arm 7.

[0026] The robot 2 is equipped with an arm drive mechanism that moves the hands 4 and 5 linearly in the horizontal direction relative to the swing arm 7 and rotates the arm 6 relative to the swing arm 7, a swing arm drive mechanism that rotates the swing arm 7 relative to the main body 8, and a swing arm lifting mechanism that raises and lowers the swing arm 7 relative to the main body 8. The swing arm drive mechanism is equipped with a motor, a reducer, etc. that are housed in a case body 13. The swing arm lifting mechanism raises and lowers the swing arm 7 together with the swing arm drive mechanism. The swing arm lifting mechanism is housed in the case body. The swing arm lifting mechanism is equipped with a motor, a ball screw that rotates by the power of the motor, etc. The configuration of the arm drive mechanism will be described below.

[0027] (Arm drive mechanism configuration) Fig. 3 is a cross-sectional view for explaining the internal configuration of the base end portion of the arm 6 and the swing arm 7 shown in Fig. 2. Fig. 4 is an enlarged view of part E in Fig. 3.

[0028] The arm drive mechanism extends and retracts the arm 6 relative to the swing arm 7 to linearly move the hands 4 and 5 in the horizontal direction (i.e., extends and retracts the arm 6 to linearly move the hands 4 and 5 in the horizontal direction relative to the swing arm 7), and also rotates the common arm unit 12 relative to the swing arm 7. The arm drive mechanism includes a common arm unit drive mechanism 18 that rotates the common arm unit 12 relative to the swing arm 7. The arm drive mechanism also includes a first tip-side arm unit drive mechanism that rotates the tip-side arm unit 10 relative to the common arm unit 12 and rotates the hand 4 relative to the tip-side arm unit 10, and a second tip-side arm unit drive mechanism that rotates the tip-side arm unit 11 relative to the common arm unit 12 and rotates the hand 5 relative to the tip-side arm unit 11.

[0029] The common arm section drive mechanism 18 includes a motor 20, a hollow reducer 21 (hereinafter referred to as "reduction gear 21") disposed in the joint section 16, and a reduction mechanism 22 for reducing the rotation of the motor 20 and transmitting the rotation to the reduction gear 21. The motor 20 is a servo motor. The motor 20 is disposed inside the swing arm 7. A pulley 19 is fixed to the output shaft of the motor 20. The reduction gear 21 and the reduction mechanism 22 reduce the rotation of the motor 20 and transmit the rotation to the common arm section 12.

[0030] The reducer 21 is an eccentric oscillating reducer (RV reducer). The reduction ratio of the reducer 21 is, for example, 1 / 30. A through-hole is formed in the radial center of the reducer 21. The through-hole passes through the reducer 21 in the vertical direction. A lower portion of the reducer 21 is disposed inside the swing arm 7. The reducer 21 includes an input shaft 23 and an output shaft 24 formed in a hollow shape, a case body 25 that rotatably holds the input shaft 23 and the output shaft 24, a magnetic fluid seal 26 disposed on the outer periphery of the output shaft 24, and a cylindrical fixed shaft 27 disposed in the radial center of the reducer 21.

[0031] The input shaft 23 is arranged such that its axial direction coincides with the up-down direction. The input shaft 23 is rotatably held in the lower end portion of the case body 25 via a bearing. The output shaft 24 is arranged such that its axial direction coincides with the up-down direction. The output shaft 24 is arranged above the input shaft 23. The output shaft 24 is rotatably held in the upper end portion of the case body 25 via a bearing. The input shaft 23 and the output shaft 24 are arranged coaxially. The output shaft 24 is fixed to the base end portion of the common arm portion 12. Specifically, the upper end surface of the output shaft 24 is fixed to the lower surface of the base end portion of the common arm portion 12. A through hole is formed in the base end portion of the common arm portion 12, leading to the inner circumferential side of the output shaft 24.

[0032] The case body 25 is fixed to the tip of the swing arm 7. Specifically, the upper end of the case body 25 is fixed to the upper surface of the tip of the swing arm 7. The fixed shaft 27 is fixed to the case body 25. The fixed shaft 27 is arranged so that the axial direction of the fixed shaft 27 coincides with the up-down direction. A portion of the fixed shaft 27 is arranged on the inner circumferential side of the input shaft 23. The inner circumferential side of the fixed shaft 27 communicates with the inner circumferential side of the output shaft 24. The inner circumferential sides of the fixed shaft 27 and the output shaft 24 form a through hole formed in the radial center of the reducer 21. The inner diameter of the output shaft 24 is larger than the inner diameter of the fixed shaft 27.

[0033] The input shaft 23 is disposed inside the case body 25. That is, the input shaft 23 is housed in the case body 25. An input gear 23b is formed integrally with the input shaft 23. The reducer 21 includes three gears 28 that mesh with the input gear 23b, a crankshaft to which the gears 28 are fixed, and an RV gear attached to the crankshaft. The gears 28 are spur gears. The three gears 28 are housed in the case body 25. The three gears 28 are arranged on concentric circles centered on the axis of the input shaft 23. The three gears 28 are also arranged at 120° intervals around the axis of the input shaft 23. Grease is housed as a lubricant in the portion of the case body 25 where the input shaft 23 and the gears 28 are disposed.

[0034] The magnetic fluid seal 26 functions to prevent air from flowing into the vacuum region VR from inside the swing arm 7. As described above, the magnetic fluid seal 26 is disposed on the outer circumferential side of the output shaft 24. The magnetic fluid seal 26 is held in the case body 25. Specifically, the magnet and pole piece of the magnetic fluid seal 26 are fixed to the inner circumferential surface of the upper end of the case body 25. A magnetic fluid is held between the inner circumferential surface of the pole piece and the outer circumferential surface of the output shaft 24.

[0035] The reduction mechanism 22 is disposed inside the swing arm 7. The reduction mechanism 22 includes an input rotating shaft 30 connected to the input shaft 23 and the motor 20, a shaft holding member 31 that rotatably holds the input rotating shaft 30, and a seal member 32 that prevents leakage of lubricant (i.e., leakage of grease) from inside the case body 25. The input rotating shaft 30 is disposed so that its axial direction coincides with the up-down direction. The axis of the input rotating shaft 30 is disposed at a position offset from the axis of the input shaft 23. In other words, the axis of the input shaft 23 and the axis of the input rotating shaft 30 are disposed at positions offset from each other.

[0036] The shaft holding member 31 is formed in a cylindrical shape. The shaft holding member 31 is disposed so that the axial direction of the shaft holding member 31 coincides with the up-down direction. The shaft holding member 31 is fixed to the case body 25. Specifically, the shaft holding member 31 is fixed to the bottom surface of the case body 25. A through-hole is formed in the bottom surface of the case body 25, leading from the bottom surface (lower surface) of the case body 25 to the interior of the case body 25, and the upper end of the shaft holding member 31 is disposed in this through-hole. A portion of the input rotating shaft 30 is disposed on the inner circumferential side of the shaft holding member 31. A bearing that rotatably supports the input rotating shaft 30 is disposed on the inner circumferential side of the shaft holding member 31. The input rotating shaft 30 is rotatably held in the case body 25 via the bearing and the shaft holding member 31.

[0037] A gear 30b disposed inside the case body 25 is integrally formed on the upper end (one end) of the input rotating shaft 30. The gear 30b is in mesh with the input gear 23b. That is, the input rotating shaft 30 is connected to the input shaft 23 inside the case body 25. The outer diameter of the gear 30b is smaller than the outer diameter of the input gear 23b. A pulley 33 disposed outside the case body 25 is fixed to the lower end (other end) of the input rotating shaft 30. That is, the reduction mechanism 22 includes the pulley 33. A belt 34 is stretched between the pulley 19 fixed to the output shaft of the motor 20 and the pulley 33. That is, the input rotating shaft 30 is connected to the motor 20 outside the case body 25. The outer diameter of the pulley 33 is larger than the outer diameter of the gear 30b.

[0038] As described above, the input rotating shaft 30 is rotatably held in the case body 25 via the bearing and the shaft holding member 31. A portion of the input rotating shaft 30 arranged on the inner circumferential side of the shaft holding member 31 forms the held portion 30c that is rotatably held in the case body 25. That is, the input rotating shaft 30 has the held portion 30c. The held portion 30c is formed in a cylindrical shape. Specifically, the held portion 30c is formed in a stepped cylindrical shape. The outer diameter of the held portion 30c is smaller than the outer diameter of the fixed shaft 27.

[0039] The sealing member 32 is a rubber oil seal formed in an annular shape. The sealing member 32 is disposed on the inner circumferential side of the shaft holding member 31. Specifically, the sealing member 32 is disposed on the inner circumferential side of the upper end portion of the shaft holding member 31. The sealing member 32 is also disposed on the outer circumferential side of the input rotating shaft 30. Specifically, the sealing member 32 is disposed on the outer circumferential side of the held portion 30c. The inner circumferential surface of the sealing member 32 contacts the outer circumferential surface of the held portion 30c with a predetermined contact pressure.

[0040] As described above, the outer diameter of the held portion 30c is smaller than the outer diameter of the fixed shaft 27. In this embodiment, the outer diameter of the portion of the held portion 30c that comes into contact with the inner circumferential surface of the seal member 32 is the maximum outer diameter of the held portion 30c that is formed in a stepped cylindrical shape, and the outer diameter of the portion of the held portion 30c that comes into contact with the inner circumferential surface of the seal member 32 is smaller than the outer diameter of the fixed shaft 27.

[0041] Like common arm drive mechanism 18, the first tip-side arm drive mechanism and the second tip-side arm drive mechanism include a motor corresponding to motor 20, a reducer corresponding to reducer 21, and a speed reduction mechanism corresponding to speed reduction mechanism 22. The motor of the first tip-side arm drive mechanism and the motor of the second tip-side arm drive mechanism are disposed inside common arm 12. Wiring drawn from the motor of the first tip-side arm drive mechanism and wiring drawn from the motor of the second tip-side arm drive mechanism are routed so as to pass through the inner periphery of output shaft 24 and the inner periphery of fixed shaft 27.

[0042] The reducer of the first tip-side arm drive mechanism is disposed at joint 36, which is the connecting part between the common arm 12 and the tip-side arm 10, and the reducer of the second tip-side arm drive mechanism is disposed at joint 37, which is the connecting part between the common arm 12 and the tip-side arm 11. The output shaft of the reducer of the first tip-side arm drive mechanism is fixed to the underside of the base end of the tip-side arm 10 via a cylindrical rotating shaft 38 (see FIG. 1 ). The output shaft of the reducer of the second tip-side arm drive mechanism is fixed to the underside of the base end of the tip-side arm 11.

[0043] The first tip-side arm drive mechanism includes a pulley that is arranged inside the base end of the tip-side arm 10 and fixed to one tip of the common arm 12 via a fixing member 39, a pulley that is arranged inside the tip end of the tip-side arm 10 and fixed to the base end of the hand 4, and a belt that is stretched across these two pulleys. The fixing member 39 is arranged outside the tip-side arm 10 and the common arm 12. Support shafts that rotatably support the pulleys are installed inside the base end of the tip-side arm 10 and inside the tip end of the tip-side arm 10.

[0044] The second tip-side arm drive mechanism includes a pulley that is arranged inside the base end of the tip-side arm 11 and fixed to the other tip end of the common arm 12 via a fixing member 40, a pulley that is arranged inside the tip end of the tip-side arm 11 and fixed to the base end of the hand 5, and a belt that is stretched across these two pulleys. The fixing member 40 is arranged outside the tip-side arm 11 and the common arm 12. Support shafts that rotatably support the pulleys are installed inside the base end of the tip-side arm 11 and inside the tip end of the tip-side arm 11.

[0045] (Main effect of this form) As described above, in this embodiment, the axis of the input shaft 23 of the reducer 21 and the axis of the input rotating shaft 30 of the reduction mechanism 22 are disposed at positions offset from each other. Also, in this embodiment, the input shaft 23 is disposed inside the case body 25 of the reducer 21, and the input rotating shaft 30 is connected to the input shaft 23 inside the case body 25 and is connected to the motor 20 outside the case body 25. Furthermore, in this embodiment, the outer diameter of the held portion 30c of the input rotating shaft 30, which comes into contact with the inner circumferential surface of the seal member 32 that prevents grease from leaking from inside the case body 25, is smaller than the outer diameter of the fixed shaft 27 of the reducer 21.

[0046] Therefore, in this embodiment, even if the wiring is arranged on the inner periphery of the fixed shaft 27, which is arranged on the inner periphery of the input shaft 23, and the outer diameter of the held portion 30c is large, the outer diameter of the held portion 30c can be reduced. Therefore, in this embodiment, the speed of the outer periphery of the held portion 30c, which comes into contact with the inner periphery of the seal member 32, can be slowed. As a result, in this embodiment, it is possible to suppress heat generation between the outer periphery of the held portion 30c and the inner periphery of the seal member 32. Therefore, in this embodiment, even if the robot 2 is used under harsh operating conditions, for example, it is possible to suppress a decrease in the viscosity of the grease contained in the case body 25 and suppress leakage of grease from inside the case body 25.

[0047] Furthermore, in this embodiment, the first tip-side arm drive mechanism and the second tip-side arm drive mechanism, like the common arm drive mechanism 18, are equipped with a motor equivalent to motor 20, a reducer equivalent to reducer 21, and a speed reduction mechanism equivalent to speed reduction mechanism 22. Therefore, in this embodiment, even if the robot 2 is used under harsh operating conditions, for example, it is possible to prevent grease from leaking from inside the case body of the reducer of the first tip-side arm drive mechanism, and it is also possible to prevent grease from leaking from inside the case body of the reducer of the second tip-side arm drive mechanism.

[0048] In this embodiment, the speed of the motor 20 is reduced by the speed reduction mechanism 22 and transmitted to the reducer 21. Therefore, in this embodiment, it is possible to lower the rotation speed of the input shaft 23 rotating inside the case body 25. Therefore, in this embodiment, it is possible to suppress heat generation inside the case body 25. As a result, in this embodiment, even if the robot 2 is used under harsh operating conditions, it is possible to effectively suppress a decrease in the viscosity of the grease contained in the case body 25 and effectively suppress leakage of the lubricant from inside the case body 25.

[0049] Similarly, in this embodiment, even if the robot 2 is used under harsh operating conditions, it is possible to effectively prevent grease from leaking from inside the case body of the reducer of the first tip-side arm drive mechanism, and it is also possible to effectively prevent grease from leaking from inside the case body of the reducer of the second tip-side arm drive mechanism.

[0050] In this embodiment, the reducer 21 is an eccentric oscillating reducer. Therefore, in this embodiment, the reduction ratio of the reducer 21 can be made smaller than when the reducer 21 is a hollow wave gearing, for example. Therefore, in this embodiment, the rotational speed of the input shaft 23 rotating inside the case body 25 can be made lower than when the reducer 21 is a hollow wave gearing, and heat generation inside the case body 25 can be effectively suppressed. As a result, in this embodiment, even when the robot 2 is used under harsh operating conditions, for example, it is possible to more effectively suppress a decrease in the viscosity of the grease contained in the case body 25 and more effectively suppress grease leakage from inside the case body 25.

[0051] Similarly, in this embodiment, even if the robot 2 is used under harsh operating conditions, it is possible to more effectively prevent grease from leaking from inside the case body of the reducer of the first tip-side arm drive mechanism, and it is also possible to more effectively prevent grease from leaking from inside the case body of the reducer of the second tip-side arm drive mechanism.

[0052] (Other embodiments) The above-described embodiment is one example of a preferred embodiment of the present invention, but the present invention is not limited to this embodiment and various modifications can be made without departing from the spirit of the present invention.

[0053] In the above-described embodiment, the reducer 21 may be a hollow reducer other than an eccentric oscillating reducer. For example, the reducer 21 may be a hollow wave gear device. In the above-described embodiment, the gear 30b formed separately from the input rotating shaft 30 may be fixed to the input rotating shaft 30. In the above-described embodiment, the pulley 33 may be formed integrally with the input rotating shaft 30.

[0054] In the above-described embodiment, the first tip-side arm drive mechanism may not have a speed reduction mechanism equivalent to speed reduction mechanism 22, and the second tip-side arm drive mechanism may not have a speed reduction mechanism equivalent to speed reduction mechanism 22. In this case, the lower ends of the input shafts of the reducers of the first tip-side arm drive mechanism and the second tip-side arm drive mechanism are disposed outside the case body of the reducer, and a belt is stretched between a pulley fixed to the lower end of the input shaft of the reducer and a pulley fixed to the output shaft of the motor.

[0055] In the above-described embodiment, if the first tip-side arm drive mechanism or the second tip-side arm drive mechanism is equipped with a speed reduction mechanism equivalent to speed reduction mechanism 22, common arm drive mechanism 18 does not need to be equipped with speed reduction mechanism 22. In this case, the lower end of input shaft 23 is disposed outside case body 25, and belt 34 is stretched between pulley 19 and a pulley fixed to the lower end of input shaft 23.

[0056] In the above-described embodiment, the robot 2 does not necessarily have to include the swing arm 7. In this case, the vertex of the common arm 12, which is formed in a generally V shape, is rotatably connected to the main body 8. In this case, the main body 8 serves as an arm support to which the base end of the arm 6 is rotatably connected. Furthermore, in the above-described embodiment, the common arm 12 is formed in a generally V-shaped block shape, but the common arm 12 may also be formed in a block shape that has an elongated oval or rectangular shape when viewed from above and that is relatively thin in thickness in the vertical direction.

[0057] In the above-described embodiment, the robot 2 may include two arms, instead of the arm 6: an arm to which the hand 4 is rotatably connected at its tip end, and an arm to which the hand 5 is rotatably connected at its tip end. In this case, the arm is configured, for example, by two arm portions rotatably connected to each other. Also, in this case, for example, the robot 2 does not include the swing arm 7, and the base ends of the two arms are rotatably connected to the main body portion 8.

[0058] In the above-described embodiment, the robot 2 may be equipped with only one hand. In this case, the robot 2 includes, for example, one arm to which the hand is rotatably connected at the tip end, and a main body to which the base end of the arm is rotatably connected. In this case, the arm is configured, for example, by two or three arm portions rotatably connected to each other. Depending on the configuration of the robot 2, items other than wiring may be arranged on the inner periphery of the fixed shaft 27. For example, as disclosed in Japanese Patent Application Laid-Open No. 2020-69577, a hollow rotating shaft to which pulleys are fixed at the upper and lower ends may be arranged on the inner periphery of the fixed shaft 27.

[0059] In the above-described embodiment, the object to be transported by the robot 2 may be an object other than a glass substrate. For example, the object to be transported by the robot 2 may be a semiconductor wafer or the like. In addition, in the above-described embodiment, the hands 4, 5, arm 6, and swing arm 7 may be disposed in the atmosphere. That is, the robot 2 may transport the object in the atmosphere. Furthermore, in the above-described embodiment, the robot 2 is a horizontal articulated robot for transporting the object, but the robot 2 may also be a vertical articulated robot used for other purposes, such as a welding robot.

[0060] (Configuration of this technology) The present technology can be configured as follows: (1) In an industrial robot having a joint, a motor, a hollow reducer disposed in the joint, and a reduction mechanism for reducing the rotation of the motor and transmitting the reduced rotation to the hollow reducer, The hollow reducer includes an input shaft formed in a hollow shape, a case body that rotatably holds the input shaft, and a cylindrical fixed shaft that is fixed to the case body and is disposed at the radial center of the hollow reducer, the reduction mechanism includes an input rotating shaft connected to the input shaft and the motor, and an annular sealing member for preventing leakage of lubricant from inside the case body; the input shaft is disposed inside the case body, a portion of the fixed shaft is disposed on the inner peripheral side of the input shaft, the input rotation shaft includes a held portion that is rotatably held by the case body, and is coupled to the input shaft inside the case body and to the motor outside the case body; the axis of the input shaft and the axis of the input rotation shaft are arranged at positions offset from each other, the sealing member is disposed on the outer circumferential side of the held portion, an inner circumferential surface of the seal member contacts an outer circumferential surface of the held portion; An industrial robot characterized in that the outer diameter of the held portion is smaller than the outer diameter of the fixed shaft. (2) A gear disposed inside the case body is formed or fixed to one end of the input rotation shaft, The industrial robot according to (1), wherein a pulley disposed outside the case body is formed or fixed to the other end of the input rotation shaft. (3) A robot includes a hand on which an object to be transported is placed, an arm to which the hand is rotatably connected at its tip end, and an arm support part to which the base end of the arm is rotatably connected, The industrial robot according to (1) or (2), wherein at least the connecting portion between the arm and the arm support portion is the joint portion. (4) The industrial robot according to any one of (1) to (3), wherein the hollow reducer is an eccentric oscillating reducer.

[0061] In this embodiment, for example, a gear that is arranged inside the case body is formed or fixed to one end of the input rotating shaft, and a pulley that is arranged outside the case body is formed or fixed to the other end of the input rotating shaft.

[0062] In this aspect, the industrial robot includes, for example, a hand on which an object to be transported is placed, an arm to which the hand is rotatably connected at its tip end, and an arm support part to which the base end of the arm is rotatably connected, and at least the connection part between the arm and the arm support part is a joint part.

[0063] In this aspect, for example, the hollow reducer is an eccentric oscillating reducer. In this case, the reduction ratio of the hollow reducer can be made smaller, for example, compared to when the hollow reducer is a hollow wave gearing. Therefore, compared to when the hollow reducer is a hollow wave gearing, the rotational speed of the input shaft rotating inside the case body can be made lower, making it possible to effectively suppress heat generation inside the case body. As a result, even when the industrial robot is used under harsh operating conditions, for example, it is possible to more effectively suppress a decrease in the viscosity of the lubricant contained in the case body and more effectively suppress leakage of the lubricant from inside the case body. [Explanation of symbols]

[0064] 2. Robots (industrial robots) 3. Substrates (glass substrates, transported objects) 4th and 5th hands 6 Arm 7 Swing arm (arm support) 16, 36, 37 Joints 20 Motor 21 Reducer (hollow reducer) 22 Reduction mechanism 23 Input shaft 25 Case body 27 Fixed axis 30 Input rotating shaft 30b Gear 30c Holding part 32 Sealing material 33 Pulley

Claims

1. In an industrial robot equipped with a joint, a motor, a hollow reducer disposed in the joint, and a reduction mechanism for reducing the rotation of the motor and transmitting the reduced rotation to the hollow reducer, The hollow reducer includes an input shaft formed in a hollow shape, a case body that rotatably holds the input shaft, and a cylindrical fixed shaft that is fixed to the case body and is disposed at the radial center of the hollow reducer, the reduction mechanism includes an input rotating shaft connected to the input shaft and the motor, and an annular sealing member for preventing leakage of lubricant from inside the case body; the input shaft is disposed inside the case body, a portion of the fixed shaft is disposed on the inner peripheral side of the input shaft, the input rotation shaft includes a held portion that is rotatably held by the case body, and is coupled to the input shaft inside the case body and to the motor outside the case body; the axis of the input shaft and the axis of the input rotation shaft are arranged at positions offset from each other, the sealing member is disposed on the outer circumferential side of the held portion, an inner circumferential surface of the seal member contacts an outer circumferential surface of the held portion; An industrial robot characterized in that the outer diameter of the held portion is smaller than the outer diameter of the fixed shaft.

2. a gear disposed inside the case body is formed or fixed to one end of the input rotation shaft; 2. The industrial robot according to claim 1, wherein a pulley disposed outside the case body is formed or fixed to the other end of the input rotary shaft.

3. a hand on which an object to be transported is placed, an arm to which the hand is rotatably connected at a tip end thereof, and an arm support part to which the arm is rotatably connected at a base end thereof; 3. The industrial robot according to claim 1, wherein at least the joint portion is a connection portion between the arm and the arm support portion.

4. 3. The industrial robot according to claim 1, wherein the hollow reducer is an eccentric oscillating reducer.

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