Robotic Arms and Robots

Abstract

To provide a robot arm which enables easy change of a position of a restriction bolt.SOLUTION: A robot arm 1a includes: a first arm 7 having a housing 8 provided with a first stopper 37; a second arm 16 which rotates relative to the first arm 7; and a joint part 13 including an outer ring part 29 fixed to the second arm 16, a second stopper 34 which is provided at the outer ring part 29 and cooperates with the first stopper 37 to restrict relative rotation of the second arm 16 relative to the first arm 7, and an inner ring part 28 which is fixed to the first arm 7 and rotates coaxially with the outer ring part 29. The housing 8 has a first opening 36 which is open to the outer ring part 29 at a position facing the outer ring part 29. The first stopper 37 protrudes from the first opening 36.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a robot arm and a robot. [Background technology]

[0002] Robots with a joint between arms are widely used. The joint includes a motor and a reducer. A joint that limits a rotation angle is disclosed in Patent Document 1. According to this, the joint includes a ring-shaped bearing. A regulating bolt is attached to a frame fixed to the inner ring of the bearing and to the outer ring. When the bearing rotates to its rotation limit, the regulating bolts interfere with each other, limiting the rotation angle of the bearing. This frame includes multiple holes. The rotation angle regulating structure is structured such that the regulating bolts are inserted into the holes and secured with nuts. When changing the rotation angle of the bearing, an operator removes the regulating bolt from the frame and replaces it with a different hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 055752 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, when removing the regulating bolt from the frame, it is necessary to disassemble the bearing, frame, and reducer that are fixed by the bolt, and there was a problem that it was not easy to change the position of the regulating bolt or to replace the regulating bolt. [Means for solving the problem]

[0005] The robot arm comprises a first member having a housing provided with a first stopper, a second member rotating relatively to the first member, an outer ring portion fixed to the second member, a second stopper provided on the outer ring portion and cooperating with the first stopper to regulate the relative rotation of the second member to the first member, and an inner ring portion fixed to the first member and rotating coaxially with the outer ring portion, and the housing has a first opening that opens toward the outer ring portion at a position opposite the outer ring portion, and the first stopper protrudes from the first opening.

[0006] The robot comprises a robotic arm as described above. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional side view showing a configuration of a robot according to a first embodiment. [Diagram 2] FIG. [Diagram 3] FIG. 4 is a schematic diagram for explaining the arrangement of a stopper. [Figure 4] Schematic diagram for explaining the operation of a stopper. [Diagram 5] Schematic diagram for explaining the operation of a stopper. [Figure 6] FIG. 11 is a schematic cross-sectional side view for explaining the configuration of a stopper according to a second embodiment. [Figure 7] FIG. 4 is a schematic diagram for explaining the arrangement of a buffer portion. [Figure 8] FIG. 13 is a schematic cross-sectional side view showing the configuration of a joint portion according to a third embodiment. [Figure 9] FIG. 13 is a schematic cross-sectional side view showing the configuration of a joint portion according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments will be described with reference to the drawings. Note that each component in each drawing is illustrated at a different scale so that each component can be easily recognized in each drawing.

[0009] First embodiment In this embodiment, a characteristic example of a robot will be described with reference to the drawings. As shown in Fig. 1, the robot 1 includes a base 2 formed in a flat plate shape. One direction on the horizontal plane of the base 2 is defined as the X direction. The direction opposite to the direction of gravity is defined as the Z direction, and the direction perpendicular to the X direction and the Z direction is defined as the Y direction.

[0010] A support base 3 is disposed on a base 2. A cavity is formed inside the support base 3, and this cavity is divided into upper and lower portions by a support plate 4. A first motor 5 is disposed below the support plate 4.

[0011] A first reducer 6 is disposed on the upper side of the support plate 4, and a rotating shaft 5a of a first motor 5 is connected to an input shaft of the first reducer 6. An output shaft 6a of the first reducer 6 is disposed on the upper side of the first reducer 6. The output shaft 6a rotates at a rotation speed reduced from the rotation speed of the rotating shaft 5a of the first motor 5. A strain wave gear device is used for the first reducer 6. A strain wave gear device is also called a Harmonic Drive (registered trademark). A hole 3a is formed in the upper surface of the support base 3, and the output shaft 6a is disposed protruding from the hole 3a.

[0012] A first arm 7 as a first member having a substantially rectangular parallelepiped shape is connected to the output shaft 6a, and the first arm 7 is rotated about the output shaft 6a. When the first motor 5 rotates, the first arm 7 is rotated.

[0013] The first arm 7 has a housing 8. The housing 8 includes an upper plate 9, a middle plate 11, and a lower plate 12. There is a space between the upper plate 9 and the middle plate 11. There is also a space between the middle plate 11 and the lower plate 12. By providing the spaces, the housing 8 is lightweight. Thus, the housing 8 includes the middle plate 11 inside.

[0014] A joint 13 is disposed on the first arm 7 at the end opposite to the first motor 5. The joint 13 includes a second reducer 14 serving as a reducer and a harmonic gear device, and a second motor 15 serving as a motor. The second reducer 14 is a harmonic gear device. The output shaft of the second reducer 14 rotates at a rotational speed reduced from the rotational speed of the rotating shaft of the second motor 15. DC motors are used for the first motor 5 and the second motor 15.

[0015] The housing 8 has a window 10 serving as a cover at the end on the negative side in the X direction. The window 10, which is a part of the housing 8, is transparent. An operator can observe the inside of the housing 8 through the window 10.

[0016] A second arm 16 is disposed as a second member connected to the joint portion 13. The first arm 7, the joint portion 13, the second arm 16, etc. constitute a robot arm 1a. The second arm 16 is rotated with respect to the first arm 7 by the second reduction gear 14. The second arm 16 rotates relatively with respect to the first arm 7. A lifting device 17 is disposed on the end of the second arm 16 opposite the second motor 15. The lifting device 17 has a linear motion mechanism, and extends and retracts by driving the linear motion mechanism.

[0017] According to this configuration, because the second reducer 14 is a strain wave gear device, it is possible to reduce the weight of the joint portion 13. In addition, because the reduction ratio of the second reducer 14 is high, it is possible to control the relative angle between the first arm 7 and the second arm 16 with good positional accuracy.

[0018] A rotation device 18 is disposed below the lifting device 17. The rotation device 18 is equipped with a step motor. An actuator 19 is disposed below the rotation device 18. The actuator 19 is lifted and lowered by the lifting device 17. Furthermore, the actuator 19 is rotated by the rotation device 18.

[0019] A control device 21 is disposed on the positive side in the X direction of the support base 3. The control device 21 controls the operation of the robot 1 by controlling the first motor 5, the second motor 15, the lifting device 17, the rotation device 18, the actuator 19, and the like.

[0020] As shown in Fig. 2, the second motor 15 has a case 22. The case 22 has a flange 22a. The flange 22a of the case 22 is fixed to the second arm 16 by a first bolt 23. A rotor 24 and a stator 25 are disposed inside the case 22. The rotor 24 is rotatably supported by a first bearing 20. The rotor 24 rotates around a rotation shaft 24a.

[0021] The second reduction gear 14 includes a wave generator 26 as a wave generator, a flexspline 27 as an external gear, and an inner ring portion 28 and an outer ring portion 29 as internal gears. Therefore, the joint portion 13 includes an inner ring portion 28 and an outer ring portion 29. The wave generator 26 is fixed to the rotor 24 and rotates in synchronization with the rotor 24. The wave generator 26 has an elliptical shape when viewed from the axial direction of the rotor 24. The flexspline 27 is disposed between the wave generator 26 and the inner ring portion 28. The flexspline 27 is an external gear with teeth formed on the inner ring portion 28 side. The inner ring portion 28 is an internal gear with teeth formed on the flexspline 27 side.

[0022] The second reduction gear 14 has an inner ring portion 28 which is an internal gear and a flexspline 27 which is a flexible external gear. The flexspline 27 partially meshes with the inner ring portion 28 and rotates relatively around the rotation shaft 24a with respect to the inner ring portion 28. A wave generator 26 is provided inside the flexspline 27 and moves the meshing position in the circumferential direction around the rotation shaft 24a. The inner ring portion 28 is connected to and integrated with the internal gear.

[0023] At the location where the major axis of the ellipse of the wave generator 26 is, the teeth of the flexspline 27 mesh with the teeth of the inner ring portion 28. At the location where the ellipse of the wave generator 26 is the minor axis, the teeth of the flexspline 27 separate from the teeth of the inner ring portion 28. The number of teeth of the inner ring portion 28 is two more than the number of teeth of the flexspline 27. When the wave generator 26 makes one revolution, the flexspline 27 and the inner ring portion 28 rotate relatively by the amount of two teeth.

[0024] A cylindrical roller 31 is disposed between the inner ring portion 28 and the outer ring portion 29, and the inner ring portion 28 and the outer ring portion 29 function as bearings. The joint portion 13 includes the inner ring portion 28 which rotates coaxially with the outer ring portion 29. The outer ring portion 29 and an end of the flexspline 27 are fixed to the flange 22a of the case 22 by a plurality of second bolts 32. In this manner, the joint portion 13 includes the second motor 15 having the second reducer 14. The outer ring portion 29 is fixed to the second arm 16 via the case 22 of the second motor 15.

[0025] When the rotor 24 rotates, the inner ring portion 28 rotates relative to the case 22. Therefore, the inner ring portion 28 becomes the output shaft of the second reduction gear 14. According to this configuration, by removing the case 22 of the second motor 15 from the second arm 16, the outer ring portion 29 also comes off from the second arm 16. Therefore, the joint portion 13 can be easily removed from the second arm 16.

[0026] The second reduction gear 14 and the second motor 15 are integrated together to form the motor unit 33. According to this configuration, the second reduction gear 14 and the second motor 15 are integrated together as the motor unit 33. Therefore, the motor unit 33 can be easily removed from the second arm 16.

[0027] A second stopper 34 is provided on the outer ring portion 29. The second stopper 34 has a head portion 34a and a threaded portion 34b. Like the second bolt 32, the second stopper 34 fixes the outer ring portion 29 and the end of the flexspline 27 to the flange 22a of the case 22. The second stopper 34 rotates around the rotation shaft 24a.

[0028] The inner ring portion 28 is fixed to the middle plate 11 of the first arm 7 by the third bolt 35. When the inner ring portion 28 rotates relative to the outer ring portion 29, the second arm 16 rotates relative to the first arm 7.

[0029] A plurality of first openings 36 are provided in the middle plate 11 of the housing 8. The first openings 36 are disposed in a position facing the outer ring portion 29 and open toward the outer ring portion 29. A female thread is formed in the first openings 36. A first stopper 37 is provided in the first openings 36. Therefore, the first stopper 37 is disposed in the first opening 36 of the middle plate 11. According to this configuration, the housing 8 has the middle plate 11 inside, so that the horizontal rigidity is increased. Therefore, the first arm 7 can be made difficult to bend. In addition, since the second stopper 34 and the first stopper 37 are inside the housing 8, the housing 8 can be structured so that the second stopper 34 and the first stopper 37 do not get entangled with the wiring connected to the second motor 15.

[0030] The first stopper 37 is disposed on the opposite side of the joint portion 13 with respect to the first arm 7. In other words, the first stopper 37 is disposed on the negative side in the Z direction of the first arm 7. According to this configuration, since the first stopper 37 is disposed on the opposite side of the joint portion 13, it is possible to adjust the position of the first stopper 37 without removing the joint portion 13.

[0031] The surface of the outer ring portion 29 on the negative side in the Z direction is separated from the middle plate 11. Therefore, there is a space on the outside of the inner ring portion 28. The second stopper 34 is disposed on the outside of the inner ring portion 28. According to this configuration, the second stopper 34 is disposed on the outside of the inner ring portion 28. Because the second stopper 34 is disposed in the space on the outside of the inner ring portion 28, the volume occupied by the joint portion 13 and the second stopper 34 can be reduced.

[0032] The lower plate 12 has a bottom opening 38 as a second opening at a location facing the second reducer 14. The first arm 7 has a bottom opening 38 at the end of the housing 8 on the joint portion 13 side, and a cover 39 that covers the bottom opening 38. The cover 39 is fixed to the lower plate 12 by a set screw 43. The cover 39 can be easily attached and detached. The cover 39 and the window portion 10 may be removed when performing maintenance on the first stopper 37. The cover 39 is transparent, and the operator can see the first stopper 37 through the cover 39. When performing maintenance on the first stopper 37, the window portion 10 may be removed, and the first stopper 37 may be operated from the window portion 10 side.

[0033] According to this configuration, the bottom opening 38 of the housing 8 is covered with the cover 39. The cover 39 can prevent dirt and dust from entering the housing 8. By removing the cover 39, the position of the first stopper 37 can be easily adjusted.

[0034] According to this configuration, since the window portion 10, which is a part of the housing 8, is transparent, it is possible to observe the inside of the housing 8. Therefore, it is possible to adjust the position of the first stopper 37 while viewing the first stopper 37.

[0035] 3 to 5 are views of the second reducer 14 viewed from the bottom opening 38 side. The cover 39 has been removed. As shown in Fig. 3, the middle plate 11 has a plurality of first openings 36 in which first stoppers 37 are installed. The first openings 36 are arranged on a concentric circle.

[0036] According to this configuration, since there are a plurality of first openings 36, the location where the first stopper 37 is installed can be freely selected.

[0037] The first stopper 37 is composed of a right first stopper 37a and a left first stopper 37b. The second stopper 34 moves by rotating between the right first stopper 37a and the left first stopper 37b around the rotation shaft 24a.

[0038] The first arm 7 has a lateral opening 40 as a second opening at the end of the housing 8 on the joint portion 13 side, and has a window portion 10 that covers the lateral opening 40.

[0039] According to this configuration, the side opening 40 of the housing 8 is covered by the window portion 10. The window portion 10 can prevent dirt and dust from entering the housing 8. By removing the window portion 10, the position of the first stopper 37 can be easily adjusted.

[0040] 4, the outer ring portion 29 and the second stopper 34 rotate in the right rotation direction 41 relative to the inner ring portion 28. At this time, the second stopper 34 can move until it interferes with the right-side first stopper 37a.

[0041] 5, the outer ring portion 29 and the second stopper 34 rotate in the left rotation direction 42 relative to the inner ring portion 28. At this time, the second stopper 34 can move until it interferes with the left first stopper 37b.

[0042] The second stopper 34 cooperates with the first stopper 37 to restrict the relative rotation of the second arm 16 with respect to the first arm 7. In addition, the first stopper 37 protrudes from the first opening 36 to the negative side in the Z direction.

[0043] According to this configuration, the first arm 7 and the second arm 16 are connected by the joint portion 13. The first stopper 37 and the second stopper 34 restrict the relative rotation between the first arm 7 and the second arm 16. When changing the restricted range, the position of the first stopper 37 is changed. Since the first stopper 37 protrudes from the first opening 36, the position of the first stopper 37 can be easily changed.

[0044] The robot 1 includes a robot arm 1a. According to this configuration, the robot 1 includes the robot arm 1a. The robot arm 1a can easily change the position of the first stopper 37. Therefore, the robot 1 can be a robot including the robot arm 1a that can easily change the operating range of the second arm 16.

[0045] Second embodiment The present embodiment differs from the first embodiment in that a first stopper 37 includes a buffer portion. Note that the same components as those in the first embodiment are given the same reference numerals, and duplicated explanations will be omitted.

[0046] 6 and 7, the robot arm 45a of the robot 45 has a middle plate 11 in a housing 8. A first opening 46 corresponding to the first opening 36 is arranged in the middle plate 11. The first opening 46 is a through hole with no thread formed therein. A first stopper 47 is arranged in the first opening 46.

[0047] The first stopper 47 is composed of a fourth bolt 48 and a buffer portion 49. A female thread 49a is formed in the buffer portion 49. The fourth bolt 48 passes through the first opening 46 and screws into the female thread 49a of the buffer portion 49. Then, the first stopper 47 is fixed to the middle plate 11. In this manner, the first stopper 47 includes the buffer portion 49.

[0048] When the second stopper 34 rotates in the right rotation direction 41 and exceeds a specified range of movement, the second stopper 34 collides with the first stopper 47. The second stopper 34 is made of steel, and the buffer portion 49 is made of aluminum. The buffer portion 49 is softer and more easily deformed than the second stopper 34. With this configuration, the buffer portion 49 absorbs the impact, so that the impact can be prevented from being transmitted to the second reducer 14 from the second stopper 34 and the first stopper 47.

[0049] Even when the second stopper 34 rotates in the left rotation direction 42, if the rotation exceeds the specified movement range, the second stopper 34 collides with the first stopper 47. Therefore, the transmission of impact from the second stopper 34 and the first stopper 47 to the second reducer 14 can be suppressed.

[0050] Third embodiment This embodiment differs from the first embodiment in that there is no flange 22a on the case 22 of the second motor 15. Note that the same components as those in the first embodiment are given the same reference numerals and redundant description will be omitted.

[0051] 8, a robot arm 52a of a robot 52 includes a first arm 53 and a second arm 54. The first arm 53 and the second arm 54 are rotatably connected by a joint portion 55. The joint portion 55 includes a second motor 56 and a second reducer 14.

[0052] The second arm 54 has a second recess 54a, and a second through hole 54b is provided on the bottom surface of the second recess 54a. The output shaft 56a of the second motor 56 is inserted into the second through hole 54b. The second motor 56 is fixed to the bottom surface of the second recess 54a by the first bolt 23.

[0053] The output shaft 56a is fixed to the wave generator 26. The flexspline 27 and the outer ring portion 29 are fixed to the second arm 54 by the second bolt 32. The second stopper 34 is also fixed to the second arm 54.

[0054] The first arm 53 has a first recess 53a. The inner ring portion 28 is fixed to the bottom surface of the first recess 53a by a third bolt 35. First openings 36 are arranged on the bottom surface of the first recess 53a along a circle centered on the output shaft 56a. First stoppers 37 are screwed into two of the first openings 36.

[0055] In this manner, the outer ring portion 29 is fixed to the second arm 54. According to this configuration, the number of parts interposed between the outer ring portion 29 and the second arm 54 can be reduced.

[0056] Fourth embodiment This embodiment differs from the first embodiment in that a first recess 53a is formed in the first arm 53, and the inner ring portion 28 is fixed to the bottom surface of the first recess 53a. This embodiment differs from the third embodiment in that a second motor 15 including a flange 22a is installed. Note that the same components as those in the first and third embodiments are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0057] 9, a robot arm 61a of a robot 61 includes a first arm 53 and a second arm 16. The first arm 53 and the second arm 16 are rotatably connected by a joint portion 55. The joint portion 55 includes a second motor 15 and a second reducer 14.

[0058] The flange 22a of the case 22 is fixed to the second arm 16 by the first bolt 23. The rotor 24 of the second motor 15 is fixed to the wave generator 26. The flexspline 27 and the outer ring portion 29 are fixed to the flange 22a by the second bolt 32. A second stopper 34 is also fixed to the flange 22a.

[0059] The first arm 53 has a first recess 53a. The inner ring portion 28 is fixed to the bottom surface of the first recess 53a by a third bolt 35. First openings 36 are arranged on the bottom surface of the first recess 53a along a circle centered on the rotor 24. First stoppers 37 are fixed to two of the first openings 36 by screws.

[0060] In this structure, since the first stopper 37 is exposed from the first arm 53, the position of the first stopper 37 can be easily changed.

[0061] Fifth embodiment In the first embodiment, the robot 1 is described that includes the joint unit 13 between the first arm 7 and the second arm 16. Alternatively, the joint between the support base 3 as the first member and the first arm 7 as the second member may be structured to include the second stopper 34 and the first stopper 37, similar to the joint unit 13.

[0062] Alternatively, a structure may be used in which second arm 16 is connected to support base 3 and actuator 19 is provided on first arm 7. Second motor 15 may be fixed to the arm on the support base 3 side, and the output of second reducer 14 may be fixed to the arm on the actuator 19 side.

[0063] In addition, when the robot has a second arm and a third arm, the joint between the second arm as the first member and the third arm as the second member may be structured to have a second stopper 34 and a first stopper 37, similar to joint portion 13.

[0064] Sixth embodiment In the first embodiment, a horizontally articulated robot has been described, but the number of joints of the robot may be arbitrary, and the present invention is also applicable to a vertically articulated robot.

[0065] Furthermore, the arrangement of the second stopper 34 and the first stopper 37 of the present invention may be incorporated into various devices having a configuration for transmitting a driving force from one side to the other side of a first member and a second member that rotate relative to each other. [Explanation of symbols]

[0066] 1, 45, 52, 61...robot, 1a, 45a, 52a, 61a...robot arm, 3...support as first member, 7...first arm as first member or second member, 8...housing, 10...window portion as cover, 11...middle plate, 13...joint portion, 14...second reducer as reducer and strain wave gear device, 15...second motor as motor, 16...second arm as second member, 22...case, 26...wave generator as wave generator, 27...flexspline as external gear, 28...inner ring portion as internal gear, 29...outer ring portion, 33...motor unit, 34...second stopper, 36, 46...first opening, 37, 47...first stopper, 38...bottom opening as second opening, 39...cover, 40...side opening as second opening, 49...buffer portion, 53...first arm, 54...second arm.

Claims

1. a first member having a housing provided with a first stopper; a second member that rotates relative to the first member; An outer ring portion fixed to the second member, and a first stopper provided on the outer ring portion and cooperating with the first stopper a second stopper for restricting the relative rotation of the second member with respect to the first member; a joint portion including an inner ring portion fixed to the first member and rotating coaxially with the outer ring portion; picture, the first stopper is disposed on an opposite side of the joint portion with respect to the first member, The housing has a first opening that is open toward the outer ring portion at a position facing the outer ring portion. A department was established, the first stopper protrudes from the first opening; The robot is characterized in that the first opening in which the first stopper is installed is a plurality of openings. arm.

2. 2. The robot arm of claim 1, The housing has a midplate therein, and the first stopper is disposed at the first opening of the midplate. The robot arm is disposed on the

3. 2. The robot arm of claim 1, The housing is provided with a recess, and the first stopper is disposed in the recess. A robotic arm characterized by:

4. 2. The robot arm of claim 1, The joint portion includes a motor having a reducer, and the outer ring portion is connected to the motor case. and fixed to the second member, and the inner ring portion serves as an output shaft of the reducer. Robot arm.

5. 5. A robot arm according to claim 4, The reduction gear and the motor are integrated to form a motor unit. A robotic arm.

6. 6. A robot arm according to claim 5, The robot arm, wherein the reducer is a strain wave gear device.

7. 7. A robotic arm according to claim 6, The wave gear device has an internal gear and a rotor that is partially meshed with the internal gear and is opposed to the internal gear. and an external gear that rotates relatively around a rotation axis and has flexibility, and a gear set inside the external gear. and a wave generator for moving the meshing position in a circumferential direction around the rotation axis. The inner ring portion is connected to the internal gear, and the second stopper is disposed outside the inner ring portion. A robot arm characterized by:

8. 2. The robot arm of claim 1, a second opening at an end of the housing and a cover covering the second opening. A robotic arm that features

9. 9. A robotic arm according to claim 8, A robot arm, wherein a portion of the housing is transparent.

10. 2. The robot arm of claim 1, The robot arm, wherein the first stopper has a buffer portion.

11. 2. The robot arm of claim 1, A robot arm, characterized in that the outer ring portion is fixed to the second member.

12. A robot comprising the robot arm according to any one of claims 1 to 11. Yat.

Images