Industrial robot

Abstract

An industrial robot is provided with: a hollow speed reducer (21) disposed in a joint part; and a speed reduction mechanism (22) for reducing the speed of the rotation of the motor and transmitting the rotation to the hollow speed reducer. An input shaft (23) of the hollow speed reducer is housed in a housing (25) of the hollow speed reducer, and a part of a stationary shaft (27) disposed in the radial center of the hollow speed reducer is disposed on the inner peripheral side of the input shaft (23). An input rotating shaft (30) of the speed reduction mechanism is provided with a held part (30c) rotatably held in a housing (25), is connected to an input shaft (23) inside the housing (25), and is connected to a motor outside the housing (25). A seal member (32) for preventing a lubricant from leaking from the inside of the housing (25) is disposed on the outer peripheral side of the held portion (30c), and the inner periphery of the seal member (32) is in contact with the outer peripheral surface of the held portion (30c). The outer diameter of the held portion (30c) is smaller than the outer diameter of the fixed shaft (27).

Description

Technical Field

[0001] This invention relates to an industrial robot. Background Technology

[0002] Industrial robots for handling glass substrates in a vacuum are known (see, for example, Patent Document 1). The industrial robot described in Patent Document 1 includes: two hands for loading the substrate; an arm connecting the two hands; a swing arm connecting the arm; and a main body connecting the swing arm. The arm includes: two front-end arm portions, each of which is rotatably connected to the two front-end arm portions; and a common arm portion, the base ends of which are rotatably connected to the common arm portion; and the common arm portion is rotatably connected to the front end of the swing arm.

[0003] Patent Document 1 describes an industrial robot comprising: a first drive mechanism and a second drive mechanism for rotating a front-end arm relative to a common arm and for rotating a hand relative to the front-end arm; and a third drive mechanism for rotating the common arm relative to a swing arm. The third drive mechanism includes a motor and a reducer connected to the motor. The reducer is located at the joint where the swing arm and the common arm connect. The reducer is a hollow wave gear assembly; that is, a hollow reducer. The input shaft of the reducer is hollow and is located 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 within the reducer housing. A pulley disposed outside the housing is fixed to one end of the input shaft. Grease is stored inside the housing as a lubricant. An annular sealing member is disposed on the outer periphery of the input shaft to prevent grease leakage from the housing. The inner periphery of the sealing member contacts the outer periphery of the input shaft with a specified contact pressure. A cylindrical fixed shaft is disposed on the inner periphery of the input shaft. Wiring extending from the first and second drive mechanisms is disposed on the inner periphery of the fixed shaft. Existing technical documents Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-54398 Summary of the Invention

[0006] In the industrial robot described in Patent Document 1, the wiring and other components in the reducer located at the joint are arranged on the inner circumference of the fixed shaft, making it easy to increase the outer diameter of the fixed shaft. Therefore, in this industrial robot, the outer diameter of the input shaft, on which the fixed shaft is located, also tends to increase. When 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 circumferential surface of the input shaft will increase, easily causing heat generation between the outer circumferential surface of the input shaft and the inner circumferential surface of the sealing component. When heat generation occurs between the outer circumferential surface of the input shaft and the inner circumferential surface of the sealing component, the temperature of the grease stored in the housing will rise, which may lead to a decrease in the viscosity of the grease. Therefore, in the case of the industrial robot described in Patent Document 1, for example, if the industrial robot is used under harsh operating conditions, the viscosity of the grease stored in the housing will decrease, posing a risk of grease leakage from the inside of the housing.

[0007] Therefore, the object of the present invention is to provide an industrial robot with a hollow reducer configured in the joint, which can suppress the leakage of lubricant from the inside of the hollow reducer housing even when used under harsh operating conditions.

[0008] To address the aforementioned problems, an industrial robot according to one aspect of the present invention includes a joint. The industrial robot comprises: a motor; a hollow reducer disposed in the joint; and a reduction mechanism for reducing the rotation of the motor and transmitting it to the hollow reducer. The hollow reducer includes: a hollow input shaft; a housing that holds the input shaft in a rotatable position; and a cylindrical fixed shaft fixed to the housing and disposed at the radial center of the hollow reducer. The reduction mechanism includes: an input rotation shaft connected to the input shaft and the motor; and an annular sealing member for preventing lubricant leakage from the inside of the housing. The input shaft is disposed inside the housing, a portion of the fixed shaft is disposed on the inner circumferential side of the input shaft, and the input rotation shaft has a retaining portion rotatably held in the housing, connected to the input shaft inside the housing, and connected to the motor outside the housing. The axis of the input shaft and the axis of the input rotation shaft are disposed at positions offset from each other. The sealing member is disposed on the outer circumferential side of the retaining portion, and the inner circumferential surface of the sealing member contacts the outer circumferential surface of the retaining portion. The outer diameter of the retaining portion is smaller than the outer diameter of the fixed shaft.

[0009] In the industrial robot of this embodiment, the reduction mechanism for slowing down 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. The axis of the input shaft and the axis of the input rotating shaft are arranged at a position offset from each other. Furthermore, in this embodiment, the input shaft is disposed inside the housing, the input rotating shaft is connected to the input shaft inside the housing, and connected to the motor outside the housing. Additionally, in this embodiment, the outer diameter of the retaining portion of the input rotating shaft that contacts the inner circumferential surface of the sealing member used to prevent lubricant leakage from inside the housing is smaller than the outer diameter of the fixed shaft.

[0010] Therefore, in this method, even if wiring is arranged on the inner circumference of the cylindrical fixed shaft located on the inner circumference of the input shaft, and the outer diameters of the fixed shaft and the input shaft are large, the outer diameter of the retained portion of the input rotating shaft can be reduced. Therefore, in this method, the speed (circumferential speed) of the outer circumferential surface of the retained portion that contacts the inner circumferential surface of the sealing member can be slowed down. As a result, in this method, heat generation between the outer circumferential surface of the retained portion of the input rotating shaft and the inner circumferential surface of the sealing member can be suppressed. Therefore, in this method, even when using an industrial robot under harsh operating conditions, the reduction in viscosity of the lubricant contained in the housing can be suppressed, and lubricant leakage from the inside of the housing can be prevented.

[0011] Furthermore, in this method, the rotational speed of the motor is reduced by a reduction mechanism before being transmitted to the hollow reducer, thus reducing the rotational speed of the input shaft rotating inside the housing. Therefore, this method can suppress heat generation inside the housing. As a result, even when using industrial robots under harsh operating conditions, this method can effectively suppress the decrease in viscosity of the lubricant contained in the housing and effectively prevent lubricant leakage from inside the housing.

[0012] As described above, in one aspect of the present invention, in an industrial robot with a hollow reducer configured at the joint, even when the industrial robot is used under harsh operating conditions, leakage of lubricant from the housing of the hollow reducer can be suppressed. Attached Figure Description

[0013] Figure 1 This is a top view of the industrial robot according to an embodiment of the present invention. Figure 2 yes Figure 1 The image shows a side view of an industrial robot. Figure 3 It is used for explanation Figure 2 The diagram shows a cross-sectional view of the base end of the arm and the internal structure of the swing arm. Figure 4 yes Figure 3 Enlarged view of section E in the middle. Detailed Implementation

[0014] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0015] (Structure of an industrial robot) Figure 1 This is a top view of the industrial robot 2 according to an embodiment of the present invention. Figure 2 yes Figure 1 The side view of industrial robot 2 shown.

[0016] The industrial robot 2 (hereinafter referred to as "robot 2") in this embodiment is a robot used to transport, for example, a glass substrate 3 for an organic EL (organic electroluminescent) display or a glass substrate 3 for a liquid crystal display (hereinafter referred to as "substrate 3"), which is the object of transport. Robot 2 is a horizontal multi-joint robot incorporated into the display manufacturing system. Robot 2 transports substrate 3 in a vacuum.

[0017] Robot 2 includes: hands 4 and 5 for loading a substrate 3; an arm 6 connecting the hands 4 and 5; a swing arm 7 connecting the arm 6; and a main body 8 connecting the swing arm 7. In this embodiment, robot 2 has two hands 4 and 5. The hands 4 and 5 are rotatably connected to the front end of the arm 6. The base end of the arm 6 is rotatably connected to the front end of the swing arm 7. The base end of the swing arm 7 is rotatably connected to the main body 8. In this embodiment, the swing arm 7 is an arm support rotatably connected to the base end of the arm 6.

[0018] Arm 6 comprises: two front-end arm portions 10 and 11, with two hands 4 and 5 rotatably connected to these two front-end arm portions 10 and 11 respectively; and a common arm portion 12, the base ends of the two front-end arm portions 10 and 11 being rotatably connected to the common arm portion 12, which is also rotatably connected to the front end of the swing arm 7. In this embodiment, arm 6 consists of two front-end arm portions 10 and 11 and a common arm portion 12. Hands 4 are rotatably connected to the front end of the front-end arm portion 10. Hands 5 are rotatably connected to the front end of the front-end arm portion 11.

[0019] Hand 4 can rotate relative to the front end arm 10 with the up-down direction as the axis of rotation. Hand 5 can rotate relative to the front end arm 11 with the up-down direction as the axis of rotation. Front end arms 10 and 11 can rotate relative to the common arm 12 with the up-down direction as the axis of rotation. Common arm 12 can rotate relative to the swing arm 7 with the up-down direction as the axis of rotation. Swing arm 7 can rotate relative to the main body 8 with the up-down direction as the axis of rotation.

[0020] Hand 4 is positioned above hand 5. Front side arm 10 is positioned above hand 4. Front side arm 11 is positioned below hand 5. Common arm 12 is positioned below front side arm 11. Common arm 12 is positioned above swing arm 7. Swing arm 7 is positioned above main body 8.

[0021] The main body 8 includes: a shell 13 formed into a bottomed cylindrical shape; and a cover 14 covering the opening at the upper end of the shell 13. The outer diameter of the cover 14 is larger than the outer diameter of the shell 13. The outer peripheral portion of the cover 14 is formed as a flange 14b extending radially outward from the shell 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 and 5, the arm 6, and the swing arm 7 are disposed in a vacuum region VR (in a vacuum). On the other hand, 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 front-end arms 10 and 11 are formed into elongated oval shapes when viewed from above and below, and are relatively thin in the vertical direction. The common arm 12 is formed into a generally V-shaped block. The central portion (apex portion) of the generally V-shaped common arm 12 is rotatably connected to the front end of the swing arm 7. Furthermore, the base end of the front-end arm 10 is rotatably connected to one front end of the generally V-shaped common arm 12, and the base end of the front-end arm 11 is rotatably connected to the other front end of the common arm 12. The swing arm 7 is formed into an elongated rectangle when viewed from above and below, and is relatively thin in the vertical direction.

[0023] The front end arms 10 and 11, as well as the common arm 12, are hollow. That is, arm 6 is hollow. Furthermore, the swing arm 7 is hollow. The interiors of the hollow front end arms 10 and 11 are a vacuum. On the other hand, the interiors of the hollow common arm 12 and swing arm 7 are at atmospheric pressure. The interior of the main body 8 is at atmospheric pressure.

[0024] In the horizontal direction, the distance between the rotation center of the shared arm 12 relative to the swing arm 7 and the rotation center of the front side arm 10 relative to the shared arm 12 is equal to the distance between the rotation center of the front side arm 10 relative to the shared arm 12 and the rotation center of the hand 4 relative to the front side arm 10. Similarly, the distance between the rotation center of the shared arm 12 relative to the swing arm 7 and the rotation center of the front side arm 11 relative to the shared arm 12 is equal to the distance between the rotation center of the front side arm 11 relative to the shared arm 12 and the rotation center of the hand 5 relative to the front side arm 11. Furthermore, in the horizontal direction, the distance between the rotation center of the shared arm 12 relative to the swing arm 7 and the rotation center of the front side arm 10 relative to the shared arm 12 is equal to the distance between the rotation center of the shared arm 12 relative to the swing arm 7 and the rotation center of the front side arm 11 relative to the shared arm 12.

[0025] Arm 6 is extendable relative to the swing arm 7 between a position where the tips of hands 4 and 5 are away from joint 16 and a position where the tips of hands 4 and 5 are close to joint 16. Joint 16 is the connection between the swing arm 7 and the common arm 12 (i.e., the connection between arm 6 and swing arm 7). In this embodiment, when the portion of arm 6 located on the front end arm 10 side extends so that the tip of hand 4 is away from joint 16, the portion of arm 6 located on the front end arm 11 side retracts; when the portion of arm 6 located on the front end arm 11 side extends so that the tip of hand 5 is away from joint 16, the portion of arm 6 located on the front end arm 10 side retracts. When arm 6 extends or retracts relative to the swing arm 7, hands 4 and 5 move linearly in the horizontal direction relative to the swing arm 7 while facing a fixed direction.

[0026] Robot 2 includes: an arm drive mechanism that causes hands 4 and 5 to move linearly in the horizontal direction relative to the swing arm 7 and to rotate arm 6 relative to the swing arm 7; a swing arm drive mechanism that causes the swing arm 7 to rotate relative to the main body 8; and a swing arm lifting mechanism that causes the swing arm 7 to rise and fall relative to the main body 8. The swing arm drive mechanism includes a motor, a reducer, etc., housed within the housing 13. The swing arm lifting mechanism, together with the swing arm drive mechanism, causes the swing arm 7 to rise and fall. The swing arm lifting mechanism is housed within the housing. The swing arm lifting mechanism includes a motor and a ball screw that rotates using the motor's power. The structure of the arm drive mechanism will be described below.

[0027] (Structure of the arm drive mechanism) Figure 3 It is used for explanation Figure 2 The cross-sectional view of the base end of arm 6 and the internal structure of swing arm 7 shown. Figure 4 yes Figure 3 Enlarged view of section E in the middle.

[0028] The arm drive mechanism extends and retracts the arm 6 relative to the swing arm 7, thereby causing the hands 4 and 5 to move linearly in the horizontal direction (i.e., extending and retracting the arm 6 causes the hands 4 and 5 to move linearly in the horizontal direction relative to the swing arm 7), and causes the common arm portion 12 to rotate relative to the swing arm 7. The arm drive mechanism includes a common arm drive mechanism 18 that rotates the common arm portion 12 relative to the swing arm 7. The arm drive mechanism also includes: a first front-end arm drive mechanism that rotates the front-end arm portion 10 relative to the common arm 12 and causes the hand 4 to rotate relative to the front-end arm portion 10; and a second front-end arm drive mechanism that rotates the front-end arm portion 11 relative to the common arm 12 and causes the hand 5 to rotate relative to the front-end arm portion 11.

[0029] The shared arm drive mechanism 18 includes: a motor 20; a hollow reducer 21 (hereinafter referred to as "reducer 21") disposed within the joint 16; and a reduction mechanism 22 for reducing the rotation of the motor 20 and transmitting it to the reducer 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 reducer 21 and the reduction mechanism 22 reduce the rotation of the motor 20 and transmit it to the shared arm 12.

[0030] The reducer 21 is an eccentric oscillating type reducer (RV reducer). The reduction ratio of the reducer 21 is, for example, 1 / 30. A through hole is formed at the radial center of the reducer 21. The through hole extends through the reducer 21 in the vertical direction. The lower part of the reducer 21 is disposed inside the swing arm 7. The reducer 21 includes: a hollow input shaft 23 and an output shaft 24; a housing 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 at the radial center of the reducer 21.

[0031] The input shaft 23 is configured such that its axial direction aligns with its vertical direction. The input shaft 23 is rotatably held on the lower end portion of the housing 25 via bearings. The output shaft 24 is configured such that its axial direction aligns with its vertical direction. The output shaft 24 is positioned above the input shaft 23. The output shaft 24 is rotatably supported on the upper end portion of the housing 25 via bearings. The input shaft 23 and output shaft 24 are coaxially arranged. The output shaft 24 is fixed to the base end portion of the common arm 12. Specifically, the upper end face of the output shaft 24 is fixed to the lower surface of the base end portion of the common arm 12. A through hole communicating with the inner circumferential side of the output shaft 24 is formed at the base end portion of the common arm 12.

[0032] The housing 25 is fixed to the front end of the swing arm 7. Specifically, the upper end of the housing 25 is fixed to the upper surface of the front end of the swing arm 7. The fixed shaft 27 is fixed to the housing 25. The fixed shaft 27 is arranged so that its axial direction is aligned with its vertical direction. A portion of the fixed shaft 27 is disposed 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 side of the fixed shaft 27 and the inner circumferential side of the output shaft 24 form a through hole formed at 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 housing 25. That is, the input shaft 23 is housed within the housing 25. The input gear 23b is integrally formed with the input shaft 23. The reducer 21 includes: three gears 28 meshing with the input gear 23b; a crankshaft on which the gears 28 are fixed; and RV gears mounted on the crankshaft, etc. The gears 28 are spur gears. The three gears 28 are housed within the housing 25. The three gears 28 are arranged on a concentric circle centered on the axis of the input shaft 23. The three gears 28 are arranged at 120° intervals around the axis of the input shaft 23. Inside the housing 25, in the portion where the input shaft 23 and gears 28 are disposed, grease is stored as a lubricant.

[0034] The magnetic fluid seal 26 prevents 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 peripheral side of the output shaft 24. The magnetic fluid seal 26 is held in the housing 25. Specifically, the magnet and pole pieces of the magnetic fluid seal 26 are fixed to the inner peripheral surface of the upper end of the housing 25. Magnetic fluid is maintained between the inner peripheral surface of the pole pieces and the outer peripheral 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 rotary shaft 30 connected to the input shaft 23 and the motor 20; a shaft retaining member 31 rotatably holding the input rotary shaft 30; and a sealing member 32 for preventing lubricant leakage from the inside of the housing 25 (i.e., grease leakage). The input rotary shaft 30 is arranged such that its axial direction is aligned with its vertical direction. The axis of the input rotary shaft 30 is disposed at a position offset from the axis of the input shaft 23. That is, the axis of the input shaft 23 and the axis of the input rotary shaft 30 are disposed at positions offset from each other.

[0036] The shaft retaining member 31 is cylindrical. The shaft retaining member 31 is arranged such that its axial direction aligns with its vertical direction. The shaft retaining member 31 is fixed to the housing 25. Specifically, the shaft retaining member 31 is fixed to the bottom surface of the housing 25. A through hole is formed on the bottom surface of the housing 25, leading from the bottom surface (lower surface) of the housing 25 to the interior of the housing 25, and the upper end of the shaft retaining member 31 is located within this through hole. A portion of the input rotating shaft 30 is disposed on the inner circumferential side of the shaft retaining member 31. A bearing is disposed on the inner circumferential side of the shaft retaining member 31 to support the input rotating shaft 30 so that it can rotate. The input rotating shaft 30 is rotatably held within the housing 25 via the bearing and the shaft retaining member 31.

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

[0038] As described above, the input rotation shaft 30 is rotatably held in the housing 25 via a bearing and a shaft retaining member 31. A portion of the input rotation shaft 30 disposed on the inner circumferential side of the shaft retaining member 31 forms a retained portion 30c, which is held rotatably by the housing 25. That is, the input rotation shaft 30 includes a retained portion 30c. The retained portion 30c is formed in a cylindrical shape. Specifically, the retained portion 30c is formed in a stepped cylindrical shape. The outer diameter of the retained portion 30c is smaller than the outer diameter of the fixed shaft 27.

[0039] The sealing member 32 is a ring-shaped rubber oil seal. The sealing member 32 is disposed on the inner circumferential side of the shaft retaining member 31. Specifically, the sealing member 32 is disposed on the inner circumferential side of the upper end of the shaft retaining member 31. The sealing member 32 is 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 retained portion 30c. The inner circumferential surface of the sealing member 32 contacts the outer circumferential surface of the retained portion 30c with a predetermined contact pressure.

[0040] As described above, the outer diameter of the retained portion 30c is smaller than the outer diameter of the fixed shaft 27. In this embodiment, the outer diameter of the portion of the retained portion 30c that contacts the inner circumferential surface of the sealing member 32 is the maximum outer diameter of the retained portion 30c. The retained portion 30c is formed in a stepped cylindrical shape, and the outer diameter of the portion of the retained portion 30c that contacts the inner circumferential surface of the sealing member 32 is smaller than the outer diameter of the fixed shaft 27.

[0041] Similar to the common arm drive mechanism 18, the first front-end arm drive mechanism and the second front-end arm drive mechanism also include a motor corresponding to the motor 20, a reducer corresponding to the reducer 21, and a reducer corresponding to the reducer mechanism 22. The motors of the first front-end arm drive mechanism and the second front-end arm drive mechanism are disposed inside the common arm 12. The wiring extending from the motor of the first front-end arm drive mechanism and the wiring extending from the motor of the second front-end arm drive mechanism are routed in a manner that passes through the inner circumference of the output shaft 24 and the inner circumference of the fixed shaft 27.

[0042] The reducer of the first front-end arm drive mechanism is disposed at the joint 36, which forms the connection between the common arm 12 and the front-end arm 10. The reducer of the second front-end arm drive mechanism is disposed at the joint 37, which forms the connection between the common arm 12 and the front-end arm 11. The output shaft of the reducer of the first front-end arm drive mechanism is connected by a cylindrical rotating shaft 38 (see...). Figure 1 The output shaft of the reducer of the second front-end arm drive mechanism is fixed to the lower surface of the base end of the front-end arm 11.

[0043] The first front-end arm drive mechanism includes: a pulley disposed inside the base end side of the front-end arm 10 and fixed to a front end side of the common arm 12 by a fixing member 39; a pulley disposed inside the front end side of the front-end arm 10 and fixed to the base end of the hand 4; and a belt mounted on the two pulleys. The fixing member 39 is disposed outside the front-end arm 10 and the common arm 12. Support shafts for supporting the pulleys to be rotatable are provided inside the base end side of the front-end arm 10 and inside the front end side of the front-end arm 10.

[0044] The second front-end arm drive mechanism includes: a pulley disposed inside the base end side of the front-end arm 11 and fixed to the other front end side of the common arm 12 by a fixing member 40; a pulley disposed inside the front end side of the front-end arm 11 and fixed to the base end of the hand 5; and a belt mounted on the two pulleys. The fixing member 40 is disposed outside the front-end arm 11 and the common arm 12. Support shafts for supporting the pulleys to be rotatable are provided inside the base end side of the front-end arm 11 and inside the front end side of the front-end arm 11.

[0045] (Main effects of this implementation method) As described above, in this embodiment, the axis of the input shaft 23 of the reducer 21 and the axis of the input rotation shaft 30 of the reduction mechanism 22 are arranged at offset positions. Furthermore, in this embodiment, the input shaft 23 is disposed inside the housing 25 of the reducer 21, and the input rotation shaft 30 is connected to the input shaft 23 inside the housing 25 and connected to the motor 20 outside the housing 25. Additionally, in this embodiment, the outer diameter of the retaining portion 30c of the input rotation shaft 30, which contacts the inner circumferential surface of the sealing member 32 used to prevent grease leakage from the inside of the housing 25, is smaller than the outer diameter of the fixed shaft 27 of the reducer 21.

[0046] Therefore, in this embodiment, by arranging the wiring on the inner circumference of the fixed shaft 27 located on the inner circumference of the input shaft 23, the outer diameter of the retained portion 30c can be reduced even if the outer diameters of the fixed shaft 27 and the input shaft 23 are large. Therefore, in this embodiment, the speed of the outer circumferential surface of the retained portion 30c in contact with the inner circumferential surface of the sealing member 32 can be slowed down. As a result, in this embodiment, heat generation between the outer circumferential surface of the retained portion 30c and the inner circumferential surface of the sealing member 32 can be suppressed. Therefore, in this embodiment, even when using the robot 2 under harsh operating conditions, the viscosity decrease of the grease contained in the housing 25 can be suppressed, thereby preventing grease leakage from the inside of the housing 25.

[0047] Furthermore, in this embodiment, the first and second front-end arm drive mechanisms, like the common arm drive mechanism 18, include a motor corresponding to the motor 20, a reducer corresponding to the reducer 21, and a reduction mechanism corresponding to the reduction mechanism 22. Therefore, in this embodiment, even when using the robot 2 under harsh operating conditions, leakage of grease from the reducer housing of the first front-end arm drive mechanism can be suppressed, and leakage of grease from the reducer housing of the second front-end arm drive mechanism can also be suppressed.

[0048] In this embodiment, the rotation of the motor 20 is reduced in speed by the reduction mechanism 22 and then transmitted to the reducer 21. Therefore, in this embodiment, the rotational speed of the input shaft 23 rotating inside the housing 25 can be reduced. Therefore, in this embodiment, heat generation inside the housing 25 can be suppressed. As a result, in this embodiment, even when using the robot 2 under harsh operating conditions, the viscosity decrease of the grease contained in the housing 25 can be effectively suppressed, and lubricant leakage from the inside of the housing 25 can be effectively suppressed.

[0049] Similarly, in this embodiment, even when using robot 2 under harsh operating conditions, it is possible to effectively prevent grease from leaking from the housing of the reducer of the first front-end arm drive mechanism, and it is also possible to effectively prevent grease from leaking from the housing of the reducer of the second front-end 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 lower than, for example, in the case where the reducer 21 is a hollow oscillating gear device. Therefore, in this embodiment, compared with the case where the reducer 21 is a hollow oscillating gear device, the rotational speed of the input shaft 23 rotating inside the housing 25 can be reduced, and heat generation inside the housing 25 can be effectively suppressed. As a result, in this embodiment, even when using the robot 2 under harsh operating conditions, the viscosity reduction of the grease contained in the housing 25 can be more effectively suppressed, and grease leakage from inside the housing 25 can be more effectively suppressed.

[0051] Similarly, in this embodiment, even when using robot 2 under harsh operating conditions, it is possible to more effectively suppress grease leakage from the housing of the reducer of the first front-end arm drive mechanism, and it is also possible to more effectively suppress grease leakage from the housing of the reducer of the second front-end arm drive mechanism.

[0052] (Other implementation methods) The above embodiments are examples of preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Various modifications can be made without departing from the spirit of the present invention.

[0053] In the above embodiments, the reducer 21 can be a hollow reducer in addition to an eccentric oscillating reducer. For example, the reducer 21 can be a hollow wave gear device. In the above embodiments, the gear 30b, which is separately formed from the input rotating shaft 30, can also be fixed to the input rotating shaft 30. In the above embodiments, the pulley 33 can also be integrally formed with the input rotating shaft 30.

[0054] In the above embodiment, the first front-end arm drive mechanism may not have a reduction mechanism equivalent to the reduction mechanism 22, and the second front-end arm drive mechanism may not have a reduction mechanism equivalent to the reduction mechanism 22. In this case, the lower ends of the input shafts of the reducers of the first and second front-end arm drive mechanisms are disposed outside the housing of the reducer, and belts are mounted on the pulley fixed to the lower end of the input shaft of the reducer and the pulley fixed to the output shaft of the motor.

[0055] Furthermore, in the above embodiment, if the first front-end arm drive mechanism or the second front-end arm drive mechanism has a reduction mechanism equivalent to the reduction mechanism 22, then the shared arm drive mechanism 18 does not need to have the reduction mechanism 22. In this case, the lower end of the input shaft 23 is disposed outside the housing 25, and a belt 34 is mounted on the pulley and pulley 19 fixed to the lower end of the input shaft 23.

[0056] In the above embodiment, the robot 2 may also omit the swing arm 7. In this case, the vertex portion of the common arm portion 12, which is formed in a generally V-shape, is rotatably connected to the main body portion 8. In this case, the main body portion 8 becomes the arm support portion, and the base end of the arm 6 is rotatably connected to the arm support portion. In addition, in the above embodiment, the common arm portion 12 is formed into a generally V-shaped block, but the common arm portion 12 may also be formed into a block that is elongated oval or rectangular in shape when viewed from the vertical direction and has a relatively thin thickness in the vertical direction.

[0057] In the above embodiment, robot 2 may have two arms instead of arm 6, one arm being rotatably connected to hand 4 at its front end, and the other arm being rotatably connected to hand 5 at its front end. In this case, the arm is formed, for example, by two arm portions that are rotatably connected to each other. In this case, for example, robot 2 does not have a swing arm 7, and the base ends of the two arms are rotatably connected to the main body 8.

[0058] In the above embodiment, robot 2 may have one hand. In this case, robot 2 may include, for example, an arm to which the hand is rotatably connected; and a main body to which the base end of the arm is rotatably connected. In this case, the arm may be composed of two or three arm parts that are rotatably connected to each other. Depending on the structure of robot 2, objects other than wiring may be arranged on the inner circumference of fixed shaft 27. For example, as disclosed in Japanese Patent Application Publication No. 2020-69577, a hollow rotating shaft with pulleys fixed to its upper and lower ends may be arranged on the inner circumference of fixed shaft 27.

[0059] In the above embodiments, the object transported by robot 2 can also be an object other than a glass substrate. For example, the object transported by robot 2 can be a semiconductor wafer, etc. In the above embodiments, the hands 4 and 5, the arm 6, and the swing arm 7 can be arranged in the atmosphere. In other words, robot 2 can transport the object in the atmosphere. In addition, in the above embodiments, robot 2 is a horizontal multi-joint robot for transporting objects, but robot 2 can also be a vertical multi-joint robot for other purposes, such as a welding robot.

[0060] (The composition of this technology) This technology can be configured as follows. (1) An industrial robot having joints, wherein... It includes: a motor; a hollow reducer disposed at the joint; and a reduction mechanism for reducing the rotation of the motor and transmitting it to the hollow reducer. The hollow reducer includes: an input shaft formed in a hollow shape; a housing that holds the input shaft in a rotatable manner; and a cylindrical fixed shaft fixed to the housing and disposed at the radial center of the hollow reducer. The reduction mechanism includes: an input rotation shaft connected to the input shaft and the motor; and an annular sealing member for preventing lubricating oil from leaking from the inside of the housing. The input shaft is disposed inside the housing. A portion of the fixed shaft is disposed on the inner circumferential side of the input shaft. The input rotating shaft has a retaining portion that is rotatably held in the housing, is connected to the input shaft inside the housing, and is connected to the motor outside the housing. The axis of the input shaft and the axis of the input rotating shaft are arranged at offset positions relative to each other. The sealing component is disposed on the outer peripheral side of the retained portion. The inner peripheral surface of the sealing component is in contact with the outer peripheral surface of the retained part. The outer diameter of the retained part is smaller than the outer diameter of the fixed shaft. (2) The industrial robot according to (1), wherein, A gear disposed inside the housing is formed or fixed at one end of the input rotating shaft. At the other end of the input rotating shaft, a pulley disposed outside the housing is formed or fixed. (3) The industrial robot according to (1) or (2), wherein, It comprises: a hand for loading an object to be transported; an arm rotatably connected to the front end of the arm; and an arm support rotatably connected to the base end of the arm. At least the connection between the arm and the arm support portion constitutes the joint portion. (4) The industrial robot according to any one of (1) to (3), wherein, The hollow reducer is an eccentric oscillating type reducer.

[0061] In this embodiment, for example, a gear is formed or fixed at one end of the input rotating shaft, the gear being disposed inside the housing, and a pulley is formed or fixed at the other end of the input rotating shaft, the pulley being disposed outside the housing.

[0062] In this embodiment, the industrial robot includes, for example, a hand for loading a transported object; an arm, the hand being rotatably connected to the front end of the arm; and an arm support, the base end of the arm being rotatably connected to the arm support, wherein at least the connection between the arm and the arm support is a joint.

[0063] In this embodiment, the hollow reducer is, for example, an eccentric oscillating reducer. In this case, compared to the case where the hollow reducer is a hollow wave gear device, the reduction ratio of the hollow reducer can be reduced. Therefore, compared to the case where the hollow reducer is a hollow wave gear device, the rotational speed of the input shaft rotating inside the housing can be reduced, and heat generation inside the housing can be effectively suppressed. As a result, even when using industrial robots under harsh operating conditions, the viscosity reduction of the lubricant contained in the housing can be more effectively suppressed, and lubricant leakage from inside the housing can be more effectively suppressed. Symbol Explanation

[0064] 2. Robots (Industrial Robots) 3. Substrate (glass substrate, object to be transported) 4, 5 hands 6 arms 7. Swing arm (arm support section) Joints 16, 36, and 37 20 motors 21. Gear reducer (hollow gear reducer) 22. Reduction Mechanism 23 Input axis 25. Housing 27 Fixed shaft 30 Input Rotation Axis 30b gear 30c is the retaining part 32 Sealing components 33. Pulley.

Claims

1. An industrial robot, comprising joints, characterized in that, It includes: a motor; a hollow reducer disposed at the joint; and a reduction mechanism for reducing the rotation of the motor and transmitting it to the hollow reducer. The hollow reducer includes: an input shaft formed in a hollow shape; a housing that holds the input shaft in a rotatable manner; and a cylindrical fixed shaft fixed to the housing and disposed at the radial center of the hollow reducer. The reduction mechanism includes: an input rotation shaft connected to the input shaft and the motor; and an annular sealing member for preventing lubricant leakage from the inside of the housing. The input shaft is disposed inside the housing. A portion of the fixed shaft is disposed on the inner circumferential side of the input shaft. The input rotating shaft has a retaining part that is rotatably held in the housing, and is connected to the input shaft inside the housing and to the motor outside the housing. The axis of the input shaft is positioned offset from the axis of the input rotation shaft. The sealing component is disposed on the outer peripheral side of the retained portion. The inner peripheral surface of the sealing component is in contact with the outer peripheral surface of the retained part. The outer diameter of the retained part is smaller than the outer diameter of the fixed shaft.

2. The industrial robot according to claim 1, characterized in that, A gear disposed inside the housing is formed or fixed at one end of the input rotating shaft. At the other end of the input rotating shaft, a pulley is formed or fixed outside the housing.

3. The industrial robot according to claim 1 or 2, characterized in that, It comprises: a hand for loading an object to be transported; an arm rotatably connected to the front end of the hand; and an arm support rotatably connected to the base end of the arm. At least the connection between the arm and the arm support portion constitutes the joint portion.

4. The industrial robot according to claim 1 or 2, characterized in that, The hollow reducer is an eccentric swing type reducer.

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