JP2020069575A - Industrial robot - Google Patents

Abstract

To provide an industrial robot equipped with a pulley to be connected to an input side of a speed reducer arranged at a joint part and a rolling bearing arranged at an inner periphery side of the pulley, which can suppress damage of the rolling bearing caused by heat generated in the speed reducer although the pulley is formed of aluminium alloy.SOLUTION: The industrial robot is equipped with: a speed reducer 22 arranged at a joint part 16; a pulley 32 made of aluminium alloy connected to an input side of the speed reducer 22; a rolling bearing 36 with an outer ring made of steel arranged at an inner periphery side of the pulley 32; and a sleeve 45 fixed to the pulley 32 and arranged between the outer ring of the rolling bearing 36 and the pulley 32 in a radial direction of the pulley 32. The sleeve 45 is formed of a material closer in heat expansion coefficient to steel than aluminium alloy or steel, and the inner peripheral surface of the sleeve 45 is in contact with the outer peripheral surface of the outer ring of the rolling bearing 36 by predetermined contact pressure.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an industrial robot having a joint section.

  Conventionally, an industrial robot that conveys a glass substrate in a vacuum is known (see, for example, Patent Document 1). The industrial robot described in Patent Document 1 includes a hand on which a glass substrate is mounted, an arm to which the hand is rotatably connected to the tip side, and a main body to which the base end side of the arm is rotatably connected. Is equipped with. The arm is composed of a first arm portion whose proximal end side is rotatably connected to the main body portion, and a second arm portion whose proximal end side is rotatably connected to the tip end side of the first arm portion. .. A hand is rotatably connected to the tip end side of the second arm portion.

  In the industrial robot described in Patent Document 1, the hand and the arm are arranged in vacuum. The first arm portion and the second arm portion are formed in a hollow shape. The pressure inside the first arm portion and the second arm portion is atmospheric pressure. Inside the first arm portion, there are a first motor for rotating the second arm portion with respect to the first arm portion and a second motor for rotating the hand with respect to the second arm portion. It is arranged. A speed reducer that decelerates the rotation of the first motor and transmits the decelerated rotation of the first motor to the second arm is disposed at the joint that serves as a connection between the first arm and the second arm. The speed reducer is a hollow speed reducer, and a hollow rotary shaft is arranged on the inner peripheral side of the speed reducer.

  Further, in the industrial robot described in Patent Document 1, a pulley is fixed to the input shaft of the speed reducer. The power of the first motor is transmitted to the pulley via a belt. A rolling bearing is arranged on the inner peripheral side of the pulley. The inner ring of the rolling bearing is fixed to the hollow rotary shaft. The inner peripheral surface of the pulley is in contact with the outer peripheral surface of the outer ring of the rolling bearing at a predetermined contact pressure, and the frictional force between the outer peripheral surface of the outer ring of the rolling bearing and the inner peripheral surface of the pulley causes the pulley and the outer ring to contact each other. And rotate together. A pulley is fixed to the lower end of the hollow rotary shaft, and the power of the second motor is transmitted to the pulley via a belt.

JP, 2014-144527, A

  In the industrial robot described in Patent Document 1, heat is generated by the speed reducer arranged at the joint. In order to efficiently dissipate the heat generated by the reducer, the pulley that is fixed to the input shaft of the reducer (that is, the pulley that contacts the input shaft of the reducer) is a material with high heat conductivity and high heat dissipation. Is preferably formed. Further, in the industrial robot described in Patent Document 1, it is preferable that the pulley be lightweight in order to reduce the moment of inertia in the joint portion. Therefore, the inventor of the present application is considering forming the pulley fixed to the input shaft of the speed reducer from an aluminum alloy.

  However, according to the study by the inventor of the present application, in the industrial robot described in Patent Document 1, when the pulley fixed to the input shaft of the reduction gear is made of aluminum alloy, the outer ring of the rolling bearing is generally made of steel. Since the coefficient of thermal expansion of the pulley is significantly larger than the coefficient of thermal expansion of the outer ring, when the pulley and the outer ring thermally expand due to the heat generated by the reducer, the outer peripheral surface of the outer ring and the inner peripheral surface of the pulley are separated. It has become clear that the contact pressure may drop and slip may occur between the outer ring and the pulley. Also, if slippage occurs between the outer ring and the pulley, frictional heat is generated between the outer ring and the pulley in addition to the heat generated by the reducer, so the rolling bearing may be damaged due to the heat. It was clarified by the study by the inventor of the present application.

  Then, the subject of this invention is an industrial robot provided with the pulley connected with the input side of the reduction gear arrange | positioned at a joint part, and the rolling bearing arrange | positioned at the inner peripheral side of a pulley, and a pulley is an aluminum alloy. An object of the present invention is to provide an industrial robot capable of suppressing damage to a rolling bearing due to heat generated in a speed reducer even if formed.

  In order to solve the above-mentioned problems, an industrial robot of the present invention is an industrial robot including a joint portion, and a reducer arranged at the joint portion, and an aluminum alloy pulley connected to an input side of the reducer. A rolling bearing having an outer ring made of steel and arranged on the inner peripheral side of the pulley, and a cylindrical sleeve fixed to the pulley and arranged between the outer ring of the rolling bearing and the pulley in the radial direction of the pulley. The sleeve is formed of a material having a coefficient of thermal expansion closer to that of steel than aluminum alloy or steel, and the inner peripheral surface of the sleeve is in contact with the outer peripheral surface of the outer ring at a predetermined contact pressure. ..

  In the industrial robot of the present invention, the inner peripheral surface of the sleeve, which is fixed to the pulley made of aluminum alloy and is arranged between the outer ring of the rolling bearing and the pulley in the radial direction of the pulley, is a rolling bearing with a predetermined contact pressure. Is in contact with the outer peripheral surface of the outer ring. Further, in the present invention, the sleeve is formed of a material or steel having a thermal expansion coefficient closer to that of steel than that of an aluminum alloy. Therefore, in the present invention, even when the pulley is formed of an aluminum alloy, when the outer ring and the sleeve of the rolling bearing thermally expand due to the influence of heat generated in the reduction gear, the outer peripheral surface of the outer ring and the inner peripheral surface of the sleeve are It is possible to suppress the decrease of the contact pressure.

  Therefore, in the present invention, even if the pulley is formed of an aluminum alloy, it suppresses the slip between the outer ring and the sleeve when the outer ring and the sleeve of the rolling bearing thermally expand due to the influence of heat generated in the reduction gear. Thus, it becomes possible to suppress the generation of frictional heat between the outer ring and the sleeve. As a result, in the present invention, even if the pulley is made of an aluminum alloy, it is possible to suppress damage to the rolling bearing due to heat generated in the speed reducer.

  In the present invention, the sleeve is preferably made of steel. With this structure, the hardness of the sleeve can be made equal to the hardness of the outer ring of the rolling bearing, or the hardness of the sleeve can be made closer to the hardness of the outer ring of the rolling bearing. Therefore, when the outer ring and the sleeve of the rolling bearing thermally expand due to the heat generated by the reducer, even if slippage occurs between the outer ring and the sleeve, it is possible to suppress wear of the outer ring and the sleeve. It will be possible.

  In the present invention, the pulley is preferably fixed to the input shaft of the speed reducer and is in contact with the input shaft of the speed reducer. According to this structure, even if the sleeve is arranged between the outer ring of the rolling bearing and the pulley in the radial direction of the pulley, the aluminum alloy pulley that comes into contact with the input shaft of the speed reducer is used in the reducer. The heat generated can be efficiently dissipated.

  In the present invention, the sleeve includes a cylindrical cylindrical portion and an annular ring portion that is connected to one end of the cylindrical portion and is connected to the inner peripheral side of the cylindrical portion, and the pulley is fixed to the input shaft. The inner peripheral surface of the cylindrical portion contacts the outer peripheral surface of the outer ring with a predetermined contact pressure, and the pulley and sleeve are fixed between the one end surface of the input shaft and the annular portion in the axial direction of the input shaft. It is preferable that the portion is sandwiched and fixed to the input shaft by a screw inserted through the annular portion and the fixed portion.

  According to this structure, it is possible to fix the pulley to the input shaft of the speed reducer and the sleeve to the pulley using a common screw. Therefore, the structure of the joint can be simplified as compared with the case where the screw for fixing the pulley to the input shaft and the screw for fixing the sleeve to the pulley are individually provided. .. Further, with this configuration, since the shape of the cylindrical portion whose inner peripheral surface contacts the outer peripheral surface of the outer ring under a predetermined contact pressure is a simple cylindrical shape, the dimensional tolerance of the inner peripheral surface of the cylindrical portion is reduced. Even if it does, it becomes possible to manufacture a sleeve easily. Therefore, it is possible to accurately form the inner peripheral surface of the cylindrical portion while reducing the manufacturing cost of the sleeve, and as a result, it is possible to suppress the variation in the contact pressure between the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the outer ring. It becomes possible to do.

  In the present invention, the industrial robot may include, for example, a hand on which an object to be conveyed is mounted, an arm to which the hand is rotatably connected to a tip side, and a body portion to which a base end side of the arm is rotatably connected. The arm includes a first arm portion whose proximal end side is rotatably connected to the main body portion, and a proximal end side is rotatably connected to the distal end side of the first arm portion and a hand is attached to the distal end side. A second arm portion that is rotatably connected is provided, and a reduction gear, a pulley, a rolling bearing, and a sleeve are arranged at a joint portion that serves as a connection portion between the first arm portion and the second arm portion.

  As described above, according to the present invention, in the industrial robot including the pulley connected to the input side of the speed reducer arranged in the joint and the rolling bearing arranged on the inner peripheral side of the pulley, the pulley is made of an aluminum alloy. Even if it is formed by, it is possible to suppress the damage of the rolling bearing due to the heat generated in the speed reducer.

It is a figure which shows the industrial robot concerning embodiment of this invention, (A) is a top view, (B) is a side view. It is sectional drawing for demonstrating the internal structure of the joint part shown in FIG. 1 from a side surface. It is an enlarged view of the E section of FIG.

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

(Overall structure of industrial robot)
FIG. 1 is a diagram showing an industrial robot 1 according to an embodiment of the present invention, (A) is a plan view, and (B) is a side view. FIG. 2 is a cross-sectional view for explaining the internal structure of the joint section 16 shown in FIG. 1 from the side.

  The industrial robot 1 (hereinafter, referred to as "robot 1") of the present embodiment includes a glass substrate 2 (hereinafter, referred to as "substrate 2") for an organic EL (organic electroluminescence) display, which is an object to be transported. It is a horizontal articulated robot for transportation. The robot 1 is used by being incorporated in a manufacturing system of an organic EL display. The robot 1 includes a hand 3 on which the substrate 2 is mounted, an arm 4 to which the hand 3 is rotatably connected to the tip side, and a main body 5 to which the base end side of the arm 4 is rotatably connected. ing.

  The robot 1 also includes a case body 7 in which the main body 5 is housed. An elevating mechanism (not shown) for elevating the main body 5 is housed in the case body 7. A disk-shaped flange 8 is fixed to the upper end of the case body 7. The flange 8 is formed with a through hole in which the upper end portion of the main body 5 is arranged. In addition, in FIG. 1 (A), illustration of the case body 7 and the flange 8 is omitted.

  The hand 3 and the arm 4 are arranged above the main body 5. Further, the hand 3 and the arm 4 are arranged above the flange 8. A portion of the robot 1 above the lower end surface of the flange 8 is arranged inside a vacuum chamber that constitutes a manufacturing system for an organic EL display. That is, the portion of the robot 1 above the lower end surface of the flange 8 is arranged in the vacuum region VR, and the hand 3 and the arm 4 are arranged in vacuum. On the other hand, the portion of the robot 1 below the lower end surface of the flange 8 is arranged in the atmosphere region AR (in the atmosphere). The robot 1 conveys the substrate 2 in a vacuum.

  The hand 3 includes a base portion 10 connected to the arm 4 and four linear fork portions 11 on which the substrate 2 is mounted. The arm 4 is composed of two arm portions, a first arm portion 13 and a second arm portion 14. The first arm portion 13 and the second arm portion 14 are formed in a hollow shape. The base end side of the first arm portion 13 is rotatably connected to the main body portion 5. The base end side of the second arm portion 14 is rotatably connected to the tip end side of the first arm portion 13. The hand 3 (specifically, the base portion 10) is rotatably connected to the tip end side of the second arm portion 14. The second arm portion 14 is arranged above the first arm portion 13. Further, the hand 3 is arranged above the second arm portion 14.

  A joint portion between the arm 4 and the main body portion 5 (that is, a joint portion between the first arm portion 13 and the main body portion 5) is a joint portion 15. The joint portion between the first arm portion 13 and the second arm portion 14 is a joint portion 16. A joint portion between the arm 4 and the hand 3 (that is, a joint portion between the second arm portion 14 and the hand 3) is a joint portion 17. That is, the robot 1 includes a plurality of joint parts 15 to 17. Specifically, the robot 1 includes three joint parts 15 to 17.

  The case body 7 accommodates a rotation mechanism (not shown) for rotating the first arm portion 13 with respect to the main body portion 5. The rotating mechanism includes a motor and a speed reducer that reduces the rotation of the motor and transmits the decelerated rotation to the first arm unit 13. A magnetic fluid seal (not shown) is arranged in the joint portion 15 to prevent air from flowing into the vacuum region VR. Further, a bellows (not shown) for preventing the inflow of air into the vacuum region VR is arranged in the joint portion 15. The bellows is arranged on the outer peripheral side of the magnetic fluid seal and expands and contracts when the main body portion 5 moves up and down.

  As described above, the first arm portion 13 and the second arm portion 14 are hollow. The pressure inside the first arm portion 13 and the second arm portion 14 which are formed in a hollow shape is atmospheric pressure. Inside the first arm portion 13, a first motor 21 for rotating the second arm portion 14 with respect to the first arm portion 13, and for rotating the hand 3 with respect to the second arm portion 14. Second motor (not shown) is arranged. The joint unit 16 is provided with a speed reducer 22 that decelerates the rotation of the first motor 21 and transmits the decelerated rotation to the second arm unit 14.

  The speed reducer 22 is a hollow speed reducer in which a through hole is formed in the radial center of the speed reducer 22. Specifically, the speed reducer 22 is a hollow wave gear device. The speed reducer 22 includes an input shaft 23 and an output shaft 24 that are hollow. The input shaft 23 is arranged so that the axial direction of the input shaft 23 and the vertical direction coincide with each other. That is, the vertical direction is the axial direction of the input shaft 23. Further, the output shaft 24 is arranged so that the axial direction of the output shaft 24 and the vertical direction coincide with each other. The output shaft 24 is arranged above the input shaft 23.

  The speed reducer 22 also includes a bearing 25 that rotatably supports the output shaft 24, and a magnetic fluid seal 26 that is arranged on the outer peripheral side of the output shaft 24. Further, the speed reducer 22 includes a rigid internal gear 28, a flexible external gear 29, a wave bearing 30 attached to the outer peripheral side of the input shaft 23, a case body 31 holding the bearing 25 and the magnetic fluid seal 26. It has and.

  The upper end portion of the case body 31 is fixed to the upper surface side of the tip end portion of the first arm portion 13. The bearing 25 is a cross roller bearing. The outer ring of the bearing 25 is fixed to the upper end of the case body 31. The inner ring of the bearing 25 is fixed to the output shaft 24. The upper end surface of the output shaft 24 is fixed to the lower surface of the base end portion of the second arm portion 14. The magnetic fluid seal 26 is arranged on the upper side of the bearing 25 and has a function of preventing air from flowing into the vacuum region VR. The magnet and pole piece of the magnetic fluid seal 26 are fixed to the inner peripheral surface of the upper end portion of the case body 31. The magnetic fluid is held between the inner peripheral surface of the pole piece and the outer peripheral surface of the output shaft 24.

  The input shaft 23 is rotatably supported by the lower end of the case body 31 via a bearing. The input shaft 23 is formed with an elliptical portion whose outer peripheral surface has an elliptical shape when viewed from above and below. The rigid internal gear 28 is fixed to the lower end of the case body 31. Internal teeth are formed on the inner peripheral surface of the rigid internal gear 28. The upper end of the flexible external gear 29 is fixed to the lower end of the output shaft 24. External teeth that mesh with the internal teeth of the rigid internal gear 28 are formed on the outer peripheral surface of the lower end of the flexible external gear 29. The flexible external gear 29 is rotatable relative to the input shaft 23.

  The wave bearing 30 is a ball bearing having a flexible inner ring and an outer ring. The wave bearing 30 is arranged along the outer peripheral surface of the elliptical portion of the input shaft 23 and is bent in an elliptical shape. The lower end portion of the flexible external gear 29 on which the external teeth are formed is arranged on the outer peripheral side of the wave bearing 30 so as to surround the wave bearing 30, and this portion is bent in an elliptical shape. The external teeth of the flexible external gear 29 mesh with the internal teeth of the rigid internal gear 28 at two locations in the longitudinal direction of the lower end side portion of the flexible external gear 29 that bends in an elliptical shape. .. When the power of the first motor 21 is transmitted to the speed reducer 22, heat is mainly generated in the speed reducer 22 at the meshing portion of the rigid internal gear 28 and the flexible external gear 29.

  A pulley 32 is connected to the input side of the speed reducer 22. Specifically, the pulley 32 is fixed to the input shaft 23 of the speed reducer 22. The pulley 32 is fixed to the lower end of the input shaft 23. The pulley 32 is rotatably supported by the lower end of the case body 31 via a bearing, and is rotatable with respect to the case body 31 together with the input shaft 23. At the center of the pulley 32, a through hole that penetrates in the vertical direction is formed. The power of the first motor 21 is transmitted to the pulley 32 via a belt 33. The belt 33 is a toothed belt.

  A hollow rotary shaft 34 is arranged on the inner peripheral side of the speed reducer 22. Specifically, the hollow rotary shaft 34 is arranged on the inner peripheral side of the input shaft 23, the output shaft 24, and the pulley 32. The hollow rotating shaft 34 is formed in a vertically elongated cylindrical shape. A bearing 35 is arranged between the outer peripheral surface of the hollow rotary shaft 34 and the inner peripheral surface of the output shaft 24. A bearing 36 is arranged between the outer peripheral surface of the hollow rotary shaft 34 and the inner peripheral surface of the pulley 32.

  A pulley 37 is fixed to the lower end of the hollow rotary shaft 34. At the center of the pulley 37, a through hole that penetrates in the vertical direction is formed. The pulley 37 is arranged below the pulley 32. The power of the second motor is transmitted to the pulley 37 via a belt 38. The belt 38 is a toothed belt. A pulley 39 is fixed to the upper end of the hollow rotary shaft 34. At the center of the pulley 39, a through hole that penetrates in the vertical direction is formed. The pulley 39 is arranged inside the base end side of the second arm portion 14.

  A reducer (not shown) that reduces the rotation of the second motor and transmits it to the hand 3 is arranged in the joint portion 17. Like the speed reducer 22, this speed reducer is a hollow wave gear device. A pulley (not shown) is fixed to the input shaft of the speed reducer, and a belt 40 is stretched over the pulley and the pulley 39. The belt 40 is a toothed belt. The output shaft of the speed reducer is fixed to the hand 3, and the case body is fixed to the tip of the second arm portion 14.

(Structure of joint)
FIG. 3 is an enlarged view of part E in FIG.

  As described above, the reduction gear 22 is arranged in the joint portion 16. Further, a pulley 32 and a bearing 36 are arranged in the joint section 16. The bearing 36 is arranged between the outer peripheral surface of the hollow rotary shaft 34 and the inner peripheral surface of the pulley 32, as described above. That is, the bearing 36 is arranged on the inner peripheral side of the pulley 32. Further, the joint portion 16 is provided with a tubular sleeve 45 arranged between the bearing 36 and the pulley 32 in the radial direction of the pulley 32.

  The bearing 36 is a rolling bearing. Specifically, the bearing 36 is a ball bearing (ball bearing), and includes a steel inner ring 36a, a steel outer ring 36b, and a plurality of steel balls arranged between the inner ring 36a and the outer ring 36b. And 36c. The inner ring 36a is fixed to the hollow rotary shaft 34. In the present embodiment, the inner ring 36a is fixed to the hollow rotary shaft 34 by a screw 46 inserted in the pulley 37 in a state of being sandwiched between the hollow rotary shaft 34 and the pulley 37 in the vertical direction.

  Specifically, a contact surface with which the upper end surface of the inner ring 36a contacts is formed at the lower end of the hollow rotary shaft 34, and this contact surface is an annular flat surface orthogonal to the vertical direction. .. Further, a through hole into which the screw 46 is inserted is formed in the pulley 37 so as to penetrate the pulley 37 in the vertical direction, and a screw hole into which the upper end of the screw 46 is screwed is formed in the lower end surface of the hollow rotary shaft 34. Has been formed. The inner ring 36a is sandwiched between the contact surface of the hollow rotary shaft 34 and the upper surface of the pulley 37, and is hollow by the screw 46 that is inserted into the through hole of the pulley 37 and screwed into the screw hole of the hollow rotary shaft 34. It is fixed to the rotating shaft 34. Further, the pulley 37 is fixed to the hollow rotary shaft 34 with a screw 46.

  The pulley 32 is made of an aluminum alloy. As described above, the through hole that penetrates in the vertical direction is formed in the center of the pulley 32. The pulley 32 includes an annular belt engaging portion 32a with which the belt 33 engages, and an annular fixed portion 32b that is fixed to the input shaft 23. The pulley 32 of this embodiment includes a belt engaging portion 32a and a fixed portion 32b. The belt engaging portion 32a constitutes a lower portion of the pulley 32, and the fixed portion 32b constitutes an upper portion of the pulley 32.

  The outer diameter of the belt engaging portion 32a is larger than the outer diameter of the fixed portion 32b. The inner diameter of the belt engaging portion 32a is larger than the inner diameter of the fixed portion 32b. A step surface 32c is formed at the boundary between the inner peripheral surface of the belt engaging portion 32a and the inner peripheral surface of the fixed portion 32b. The step surface 32c is a plane orthogonal to the vertical direction. The step surface 32c is an annular plane centered on the shaft center of the pulley 32. A plurality of teeth are formed on the outer peripheral surface of the belt engaging portion 32a. A through hole through which a screw 47 for fixing the pulley 32 to the input shaft 23 is inserted is formed in an inner portion of the fixed portion 32b in the radial direction of the pulley 32. The through hole penetrates the fixed portion 32b in the vertical direction.

  The sleeve 45 is made of steel. The sleeve 45 includes a cylindrical cylindrical portion 45a and a circular annular portion 45b connected to one end of the cylindrical portion 45a. The sleeve 45 of this embodiment includes a cylindrical portion 45a and an annular portion 45b. The cylindrical portion 45a is arranged so that the axial direction of the cylindrical portion 45a and the vertical direction coincide with each other. The annular portion 45b is connected to the upper end of the cylindrical portion 45a. The annular portion 45b is connected to the inner peripheral side of the cylindrical portion 45a. The cylindrical portion 45a and the annular portion 45b are coaxially arranged.

  The outer diameter of the cylindrical portion 45a is substantially equal to the inner diameter of the belt engaging portion 32a. The inner diameter of the annular portion 45b is substantially equal to the inner diameter of the fixed portion 32b. The outer peripheral surface of the cylindrical portion 45a is in contact with the inner peripheral surface of the belt engaging portion 32a. The upper surface of the annular portion 45b is in contact with the step surface 32c. The annular portion 45b is formed with a through hole into which the screw 47 is inserted. The through hole penetrates the annular portion 45b in the vertical direction.

  The sleeve 45 is fixed to the pulley 32 and the input shaft 23. Further, as described above, the pulley 32 is fixed to the lower end of the input shaft 23. Specifically, in the vertical direction, the pulley 32 and the sleeve 45 have a through hole of the annular portion 45b and a fixed portion 32b sandwiched between the lower end surface of the input shaft 23 and the annular portion 45b. It is fixed to the input shaft 23 by a screw 47 inserted through the through hole of the fixed portion 32b. A screw hole into which the upper end of the screw 47 is screwed is formed on the lower end surface of the input shaft 23.

  The upper end surface of the fixed portion 32b is in contact with the lower end surface of the input shaft 23. That is, the pulley 32 is in contact with the input shaft 23. The sleeve 45 is arranged between the outer ring 36 b of the bearing 36 and the pulley 32 in the radial direction of the pulley 32. The inner peripheral surface of the sleeve 45 is in contact with the outer peripheral surface of the outer ring 36b of the bearing 36 with a predetermined contact pressure. Specifically, the cylindrical portion 45a of the sleeve 45 is arranged between the outer ring 36b of the bearing 36 and the belt engaging portion 32a of the pulley 32 in the radial direction of the pulley 32, and the inner peripheral surface of the cylindrical portion 45a is The outer ring 36b is in contact with the outer peripheral surface thereof at a predetermined contact pressure. In this embodiment, the outer ring 36b is fitted in the sleeve 45 by intermediate fitting.

(Main effects of this embodiment)
As described above, in the present embodiment, the sleeve 45 whose inner peripheral surface contacts the outer peripheral surface of the outer race 36b of the steel bearing 36 with a predetermined contact pressure is made of steel. Therefore, in the present embodiment, even if the pulley 32 is formed of an aluminum alloy, when the outer ring 36b and the sleeve 45 are thermally expanded due to the influence of heat generated in the speed reducer 22, the outer peripheral surface of the outer ring 36b and the inner surface of the sleeve 45 are It is possible to suppress a decrease in contact pressure with the peripheral surface.

  Therefore, in the present embodiment, even if the pulley 32 is formed of an aluminum alloy, when the outer ring 36b and the sleeve 45 are thermally expanded by the influence of the heat generated in the speed reducer 22, slippage between the outer ring 36b and the sleeve 45 occurs. It is possible to suppress the occurrence of frictional heat between the outer ring 36b and the sleeve 45 by suppressing the above. As a result, in this embodiment, even if the pulley 32 is made of an aluminum alloy, it is possible to suppress damage to the bearing 36 due to heat generated in the speed reducer 22.

  Further, in the present embodiment, since the sleeve 45 is made of steel, it is possible to make the hardness of the sleeve 45 the same as the hardness of the outer ring 36b, or to make the hardness of the sleeve 45 close to the hardness of the outer ring 36b. .. Therefore, in the present embodiment, when the outer ring 36b and the sleeve 45 thermally expand due to the influence of the heat generated in the speed reducer 22, even if a slip occurs between the outer ring 36b and the sleeve 45, the outer ring 36b and the sleeve 45 may be slipped. It becomes possible to suppress the wear of 45.

  In this embodiment, the shape of the cylindrical portion 45a whose inner peripheral surface contacts the outer peripheral surface of the outer ring 36b with a predetermined contact pressure is a simple cylindrical shape. Therefore, in this embodiment, the sleeve 45 can be easily manufactured even if the dimensional tolerance of the inner peripheral surface of the cylindrical portion 45a is reduced. Therefore, in this embodiment, it is possible to accurately form the inner peripheral surface of the cylindrical portion 45a while reducing the manufacturing cost of the sleeve 45, and as a result, the inner peripheral surface of the cylindrical portion 45a and the outer peripheral surface of the outer ring 36b. It is possible to suppress the variation of the contact pressure with.

  In this embodiment, the pulley 32 is in contact with the input shaft 23 of the speed reducer 22. Therefore, in the present embodiment, even if the sleeve 45 is arranged between the outer ring 36b and the pulley 32 in the radial direction of the pulley 32, the speed reducer 22 is provided by using the aluminum alloy pulley 32 that contacts the input shaft 23. It is possible to efficiently dissipate the heat generated in.

  In the present embodiment, the pulley 32 and the sleeve 45 are arranged in the vertical direction such that the fixed portion 32b is sandwiched between the lower end surface of the input shaft 23 and the annular portion 45b in the vertical direction. It is fixed to the input shaft 23 by a screw 47 inserted through the through hole of the fixing portion 32b. That is, in this embodiment, the pulley 32 is fixed to the input shaft 23 and the sleeve 45 is fixed to the pulley 32 by the common screw 47. Therefore, in the present embodiment, as compared with the case where the screw for fixing the pulley 32 to the input shaft 23 and the screw for fixing the sleeve 45 to the pulley 32 are individually provided, the structure of the joint portion 16 is configured. Can be simplified.

(Other embodiments)
The embodiment described above is an example of the preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

  In the above-mentioned form, the sleeve 45 may be made of a material other than steel. Specifically, the sleeve 45 may be formed of a material having a thermal expansion coefficient closer to that of steel than that of an aluminum alloy. For example, the sleeve 45 may be formed of a copper alloy such as brass (brass). Even in this case, when the outer ring 36b and the sleeve 45 are thermally expanded under the influence of the heat generated in the speed reducer 22, a reduction in the contact pressure between the outer peripheral surface of the outer ring 36b and the inner peripheral surface of the sleeve 45 is suppressed. Therefore, even if the pulley 32 is made of an aluminum alloy, it is possible to suppress damage to the bearing 36 due to heat generated in the speed reducer 22. Even in this case, the sleeve 45 is preferably made of a material whose hardness is closer to that of steel than that of an aluminum alloy.

  In the above-mentioned form, a screw for fixing the pulley 32 to the input shaft 23 and a screw for fixing the sleeve 45 to the pulley 32 may be separately provided. Further, in the above-described embodiment, the pulley 32 may not be in contact with the input shaft 23 of the speed reducer 22. In this case, the sleeve 45 is in contact with the input shaft 23. Furthermore, in the above-mentioned form, the bearing 36 may be a roller bearing.

  In the above-described embodiment, the inner ring 36a may be fitted and fixed to the lower end of the hollow rotary shaft 34 by an interference fit, or may be fixed to the lower end of the hollow rotary shaft 34 by another fixing means. good. Further, in the above-described embodiment, similarly to the joint portion 16, the aluminum alloy pulley is fixed to the input shaft of the reduction gear arranged in the joint portion 17, and the bearing 36 is arranged on the inner peripheral side of the pulley. The sleeve 45 may be arranged between the bearing 36 and the pulley in the radial direction of the pulley.

  In the above-mentioned form, the hand 3 and the arm 4 may be arranged in the atmosphere. That is, the robot 1 may transfer the substrate 2 in the atmosphere. Further, in the above-described embodiment, the inside of the first arm portion 13 and the second arm portion 14 may be in a vacuum. Further, in the above-described embodiment, one motor rotates the second arm portion 14 with respect to the first arm portion 13 and rotates the hand 3 with respect to the second arm portion 14. A mechanism for transmitting power from the motor to the arm 4 may be configured.

  In the above-mentioned form, arm 4 may be constituted by three or more arm parts. In addition, in the above-described embodiment, the arm 4 is configured by one first arm portion 13 and two second arm portions 14 rotatably connected to the one first arm portion 13. May be. Furthermore, in the above-described embodiment, the robot 1 is rotatably connected to the two arms 4 whose proximal ends are rotatably connected to the main body 5 and the respective distal ends of the two arms 4. Two hands 3 may be provided. That is, the robot 1 may include four or more joints. Further, the number of joints included in the robot 1 may be one.

  In the above-described embodiment, the transport target transported by the robot 1 is the substrate 2 for the organic EL display, but the transport target transported by the robot 1 may be a glass substrate for the liquid crystal display, It may be a semiconductor wafer or the like. Further, in the above-described embodiment, the robot 1 is a horizontal articulated robot for carrying an object to be carried, but the robot 1 is a vertical articulated robot used for other purposes such as a welding robot. May be

  In addition, in the above-mentioned form, the pulley 32 may be formed of a material other than an aluminum alloy. In this case, for example, the pulley 32 is formed of metal or resin such as brass having a thermal expansion coefficient relatively higher than that of steel.

1 robot (industrial robot)
2 substrates (glass substrate, object to be transported)
3 Hand 4 Arm 5 Main Body 13 First Arm Part 14 Second Arm Part 16 Joint Part 22 Reducer 23 Input Shaft 32 Pulley 32b Fixed Part 36 Bearing (Rolling Bearing)
36b Outer ring 45 Sleeve 45a Cylindrical part 45b Annular part 47 Screw

Claims (5)

In an industrial robot equipped with joints,
A speed reducer arranged at the joint, an aluminum alloy pulley connected to the input side of the speed reducer, a rolling bearing having an outer ring made of steel and arranged on the inner peripheral side of the pulley, A tubular sleeve fixed to the pulley and arranged between the outer ring of the rolling bearing and the pulley in the radial direction of the pulley,
The sleeve is formed of a material or steel whose coefficient of thermal expansion is closer to that of steel than aluminum alloy,
The industrial robot, wherein the inner peripheral surface of the sleeve is in contact with the outer peripheral surface of the outer ring with a predetermined contact pressure.   The industrial robot according to claim 1, wherein the sleeve is made of steel.   3. The industrial robot according to claim 1, wherein the pulley is fixed to the input shaft of the speed reducer and is in contact with the input shaft. The sleeve includes a cylindrical cylindrical portion and an annular ring portion that is connected to one end of the cylindrical portion and is connected to an inner peripheral side of the cylindrical portion,
The pulley includes a fixed portion fixed to the input shaft,
The inner peripheral surface of the cylindrical portion contacts the outer peripheral surface of the outer ring at a predetermined contact pressure,
The pulley and the sleeve are attached to the annular portion and the fixed portion in a state where the fixed portion is sandwiched between the one end surface of the input shaft and the annular portion in the axial direction of the input shaft. The industrial robot according to claim 3, wherein the industrial robot is fixed to the input shaft by a screw that is inserted. A hand on which an object to be conveyed is mounted; an arm to which the hand is rotatably connected to a tip side; and a body to which a base end side of the arm is rotatably connected,
The arm includes a first arm portion whose proximal end side is rotatably connected to the main body portion, a proximal end side which is rotatably connected to the distal end side of the first arm portion, and the hand which is connected to the distal end side. A second arm portion rotatably connected,
The reducer, the pulley, the rolling bearing, and the sleeve are arranged in the joint portion that is a connecting portion between the first arm portion and the second arm portion. The industrial robot according to any one of 4 above.

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