Joint structure of industrial robots

Abstract

The present invention provides a joint structure (1) of a robot, comprising: a first component (4); a second component (5), which is supported by the first component (4) so ​​as to be rotatable around a horizontal rotation axis (B) relative to the first component (4); and an actuator, which drives the second component (5) to rotate the second component (5) relative to the first component (4), at least one of the first component (4) and the second component (5) is provided with a through hole (14), the through hole (14) connecting a lubrication space sealed with lubricating material of the actuator with an external space, and the number of the through holes (14) is more than three, and they are arranged in a spaced-apart manner in a circumferential direction centered on the horizontal rotation axis (B).

Description

Technical Field

[0001] The invention relates to a joint structure of an industrial robot. Background Art

[0002] The joint shaft of the industrial robot is provided with a speed reducer etc. for reducing the rotation speed of the motor to obtain the required torque. The speed reducer etc. are arranged in a closed space and lubricated by a lubricant filled in the space.

[0003] A lubricant supply port is provided at a lower portion of the speed reducer, and a lubricant discharge port is provided at an upper portion of the speed reducer (for example, refer to Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 3977326 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the joint structure of Patent Document 1, when the lubricant is supplied and discharged, the joint axis of the robot is moved so that the lubricant supply port is arranged at the bottom and the lubricant discharge port is arranged at the top. In addition, when the installation angle of the robot designed to be installed on the ground is changed, the lubricant supply port and the lubricant discharge port cannot be arranged in a vertical positional relationship in this state.

[0009] Therefore, it is desired to perform the supply and discharge operations of the lubricant without changing the posture of the robot and to be able to efficiently perform the supply and discharge operations of the lubricant even for robots installed at different angles.

[0010] Solutions for solving problems

[0011] One aspect of the present application is a joint structure of a robot, comprising: a first member; a second member, which is supported by the first member so as to be rotatable around a horizontal rotation axis relative to the first member; and an actuator, which drives the second member to rotate the second member relative to the first member, at least one of the first member and the second member is provided with a through hole, which connects a lubrication space for enclosing a lubricating material of the actuator with an external space, the number of the through holes is more than three, and the through holes are arranged at intervals in a circumferential direction centered on the horizontal rotation axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1This is a schematic diagram of a robot having a joint structure according to one embodiment of the present application.

[0013] Figure 2 To express Figure 1 A partial enlarged view of the joint structure.

[0014] Figure 3 for Figure 1 Longitudinal section view of the joint structure.

[0015] Figure 4 To express that Figure 1 A partial enlarged view of the robot when it is set on a horizontal ground.

[0016] Figure 5 To express that Figure 1 A partial enlarged view of the robot set on a vertical wall.

[0017] Figure 6 For the general Figure 1 A schematic diagram illustrating the positions of through holes when a robot is installed on a mounting surface inclined at 22.5 degrees with respect to a horizontal plane.

[0018] Figure 7 To express Figure 2 A partially enlarged view of a deformation example of the joint structure.

[0019] Figure 8 To express in Figure 7 A partial enlarged view of the state where the angle of the robot arm is changed in the joint structure.

[0020] Fig. 9 To express Figure 2 A partially enlarged view of other variations of the joint structure.

[0021] Fig.10 To express Fig. 9 An enlarged longitudinal cross-sectional view of a portion of the joint structure. DETAILED DESCRIPTION

[0022] Hereinafter, a robot joint structure 1 according to an embodiment of the present application will be described with reference to the drawings.

[0023] like Figure 1 As shown, the joint structure 1 according to the present embodiment is mounted on a six-axis multi-articulated robot 2, for example.

[0024] The robot 2 includes a base 3 installed on the ground, and a rotating body (first member) 4 supported by the base 3 so as to be rotatable about a first axis A that is vertical to the base 3 .

[0025] In addition, the robot 2 includes: a first robot arm (second component) 5, which is supported by the rotating body 4 so as to be able to swing around a horizontal second axis B relative to the rotating body 4; and a second robot arm 6, which is supported by the first robot arm 5 so as to be able to swing around a horizontal third axis C relative to the first robot arm 5.

[0026] Furthermore, a three-axis wrist unit 7 is mounted on the front end of the second robot arm 6 .

[0027] like Figure 2 and Figure 3 As shown, the joint structure 1 according to the present embodiment includes: a rotating body 4; a first robot arm 5, which is supported by the rotating body 4 so as to be rotatable around a second axis B relative to the rotating body 4; and an actuator 8, which drives the first robot arm 5 so as to rotate the first robot arm 5 relative to the rotating body 4. The actuator 8 includes: a servo motor 9, which is installed on the outside of a bracket 11 constituting a part of the rotating body 4; and a reducer 12, which is installed between the inside of the bracket 11 and the first robot arm 5.

[0028] A lubrication space 13 sealed by a sealing member (not shown) is provided between the bracket 11, the speed reducer 12, and the first robot arm 5. An input gear (not shown) fixed to the shaft 9a of the servo motor 9 and a lubricant for lubricating various parts inside the speed reducer 12 are enclosed in the lubrication space 13. The speed reducer 12 reduces the rotation of the shaft 9a of the servo motor 9 and transmits it to the first robot arm 5, thereby driving the first robot arm 5 to rotate relative to the rotating body 4.

[0029] In this embodiment, the bracket 11 is provided with a plurality of through holes 14 that communicate the lubrication space 13 with the external space 15. The through holes 14 are formed with internal threads for installing plugs (not shown). The through holes 14 are blocked by fastening the plugs to the internal threads, thereby sealing the lubricating material in the lubrication space 13, and the lubricating material can be led out to the external space 15 through the through holes 14 by removing the plugs.

[0030] The through holes 14 are formed at eight locations of the bracket 11 in a manner substantially parallel to the second axis B, and the eight locations are equally spaced along the circumferential direction around the second axis B. Seven of the eight through holes 14 may be blocked with plugs, and an injection port for supplying a lubricant may be installed at the remaining location.

[0031] The operation of the joint structure 1 of the robot 2 according to the present embodiment configured as described above will be described.

[0032] Depending on the angle of the installation surface where the robot 2 having the joint structure 1 according to this embodiment is installed, an injection port is installed in the through hole 14 located at the bottom when installed on the installation surface, and other through holes 14 are blocked by plugs.

[0033] For example, Figure 4 As shown, when the robot 2 is placed on a substantially horizontal ground 16 , an injection port is installed in the through hole 14 disposed at a position closest to the base 3 , and the other through holes 14 are blocked by plugs.

[0034] On the other hand, Figure 5 As shown, when the robot 2 is installed on a substantially vertical wall surface 17 , an injection port is installed in the through hole 14 located at the bottom when the rotating body 4 is located at the origin position, and other through holes 14 are blocked by plugs.

[0035] Next, the replacement operation of the lubricant of the joint structure 1 of the robot 2 according to the present embodiment will be described.

[0036] like Figure 4 As shown, when the robot 2 is placed on a substantially horizontal ground 16 , the plug of the uppermost through-hole 14 among the eight through-holes 14 is removed, and the lubricant is supplied from the injection port installed in the lowermost through-hole 14 .

[0037] Thus, new lubricant is filled into the lubricating space 13 from the injection port, and the old lubricant in the lubricating space 13 is pushed from the bottom to the top and discharged to the external space 15 through the open through hole 14 located at the top. Before the new lubricant is discharged through the through hole 14, the supply of lubricant through the injection port is continued, so that the lubricant in the lubricating space 13 can be replaced with the new lubricant.

[0038] In the present embodiment, the through holes 14 are arranged at intervals of 45° along the circumferential direction around the second axis B. Therefore, if the setting angle of the robot 2 is an integer multiple of 45°, any one of the through holes 14 at the eight locations can be arranged at the uppermost portion of the lubrication space 13, and another through hole 14 can be arranged at the lowermost portion of the lubrication space 13.

[0039] On the other hand, the robot 2 can be installed on an installation surface at any angle. Depending on the installation angle of the robot 2 , there may be a situation where any through hole 14 is not arranged at the uppermost or lowermost position of the lubrication space 13 .

[0040] Reference Figure 6 This point will be explained.

[0041] exist Figure 6In the figure, the positions of the through holes 14 when the angle of the setting surface is 22.5° with the horizontal plane (setting angle is 22.5°) are indicated by solid lines. In addition, for comparison, the through holes 14 located at the top and bottom of the through holes 14 when the setting surface is horizontal (setting angle is 0°) are indicated by dotted lines.

[0042] Reference Figure 6 When the setting angle of the robot 2 is 22.5°, two uppermost through holes 14 are arranged in the horizontal direction at a position slightly lower than the uppermost through hole 14 when the setting angle is 0°. In addition, when the setting angle is 22.5°, two lowermost through holes 14 are arranged in the horizontal direction at a position slightly higher than the lowermost through hole 14 when the setting angle is 0°.

[0043] That is, when the setting angle of the robot 2 is 0°, any through hole 14 is arranged at the top and bottom of the lubrication space 13. On the other hand, when the setting angle is an odd multiple of 22.5°, the top through hole 14 becomes the lowest and the bottom through hole 14 becomes the highest.

[0044] However, if Figure 6 As shown, the height of the top through hole 14 when the setting angle is 0° is set to H, the height of the top through hole 14 when the setting angle is an odd multiple of 22.5° is 4% lower, and the bottom through hole 14 when the setting angle is an odd multiple of 22.5° is configured at a position where the height is increased by 4%.

[0045] Therefore, according to the joint structure 1 of the present embodiment, even if the setting angle of the robot 2 is set to an arbitrary angle, the heights of the uppermost and lowermost through holes 14 can be arranged within a range of 4% respectively, without significantly changing the lubricant supply position and the lubricant discharge position relative to the lubrication space 13. As a result, there is an advantage that the lubricant in the lubrication space 13 can be efficiently replaced regardless of the setting angle of the robot 2.

[0046] In this embodiment, eight through holes 14 are provided, but any number of through holes 14 may be provided as long as the number is at least three. As the number of through holes 14 increases, the positional variation of the uppermost and lowermost through holes 14 corresponding to the installation angle decreases.

[0047] In addition, in the present embodiment, the through holes 14 are arranged at equal intervals on a single circle centered on the second axis B, but instead, a plurality of pairs of two through holes 14 arranged at positions spaced 180° apart around the second axis B may be arranged unevenly in the circumferential direction. When the installation angle of the robot 2 is limited, the variation of the lubricant supply position and the lubricant discharge position corresponding to the installation angle can be suppressed within the limited range.

[0048] In addition, in the present embodiment, the through hole 14 is formed in the rotating body 4 around the second axis B, wherein the second axis B is arranged in a positional relationship that is twisted relative to the first axis A. Therefore, as the setting angle increases, when the rotating body 4 is arranged at a position other than the origin position around the first axis A relative to the base 3, the positional relationship between the lubricant supply position and the lubricant discharge position cannot be arranged up and down.

[0049] Therefore, the larger the setting angle is, the more it is necessary to rotate the rotating body 4 so that the second axis B approaches the horizontal direction when performing the supply and discharge operations of the lubricant.

[0050] In addition, in this embodiment, the rotating body 4 is provided with a through hole 14, but instead, as Figure 7 and Figure 8 As shown, a through hole 14' may also be formed on the first robot arm 5'.

[0051] exist Figure 7 and Figure 8 In the example shown, eight through holes 14' are formed on the first robot arm 5' at equal intervals along the circumference around the second axis B. Figure 7 and Figure 8 As shown, whenever the angle of the first robot arm 5' around the second axis B changes by an integer multiple of 45°, the through holes 14' are arranged in the same phase.

[0052] In addition, whenever the posture of the first robot arm 5' changes by an odd multiple of 22.5°, the height difference between the uppermost through hole 14' and the lowermost through hole 14' is the smallest, but this change is slight. Therefore, even in this joint structure 1', regardless of the angle of the first robot arm 5', the supply and discharge operation of the lubricant can be performed efficiently.

[0053] Even in this case, when the setting angle of the robot 2 is other than 0°, although it is necessary to rotate the rotating body 4 so that the second axis B is close to horizontal when supplying and discharging the lubricant, it is not necessary to change the angle of the first robot arm 5'. For example, there is an advantage that in the case where a large tool is attached to the front end of the wrist, in order to supply and discharge the lubricant, it is only necessary to avoid interference between the tool and other components and keep the robot arm inactive.

[0054] In addition, if Fig. 9 and Fig.10 As shown, the heat dissipation components 18 a and 18 b may be installed inside and outside the lubrication space 13 by utilizing at least one through hole 14 provided in the bracket 11 .

[0055] That is, Fig. 9 and Fig.10 As shown, annular heat dissipating members 18a and 18b are disposed inside and outside the lubrication space 13 via the bracket 11. For example, the inner heat dissipating member 18b is provided with a boss that fits into the through hole 14 of the bracket 11, and a threaded hole 19 is formed in advance in the boss.

[0056] The two heat dissipation members 18a and 18b are fixed in a tightly fitted state by fastening bolts inserted into the through holes of the outer heat dissipation member 18a to the threaded holes 19 of the inner heat dissipation member 18b. The heat dissipation members 18a and 18b are made of a material with high thermal conductivity, such as aluminum, tungsten, or molybdenum.

[0057] Thus, the heat of the lubrication space 13 and the lubricant is released to the external space 15 via the heat dissipating members 18 a and 18 b , so that the lubrication space 13 and the lubricant can be cooled.

[0058] Thus, the heat dissipating members 18 a and 18 b can be fixed by bolts, and the bolts can be removed from the two screw holes 19 in an upper and lower relationship in the vertical direction to be used as the lubricant supply port and the lubricant discharge port.

[0059] In this case, by forming a threaded hole in the through hole of the outer heat dissipation member 18a in advance and forming a through hole in the inner heat dissipation member 18b in advance, it is only necessary to remove the bolt and install the injection port in the threaded hole of the outer heat dissipation member 18a for the through hole for supplying the lubricant. In addition, it is only necessary to remove the bolt and open the through hole of the inner heat dissipation member 18b for the through hole for discharging the lubricant.

[0060] Thus, by suppressing an excessive temperature rise of the lubricant, it is possible to suppress the aging of the lubricant and extend the replacement cycle of the lubricant.

[0061] In addition, in the above-described embodiment, the joint structure 1 of the robot 2 is exemplified, but instead, a joint structure 1 driven around another horizontal rotation axis may be applied. For example, a joint structure 1 having a first robot arm 5, a second robot arm 6 rotating around a third axis C, and an actuator 8 may also be applied.

[0062] In addition, although one through hole 14 is provided as each of the lubricant supply port and the lubricant discharge port, the present invention is not limited thereto, and the number of through holes 14 used as at least one of the lubricant supply port and the lubricant discharge port may be plural.

[0063] Description of Reference Numerals

[0064] 1. 1': Joint structure

[0065] 2: Robot

[0066] 4, 4': Rotating body (first component)

[0067] 5, 5': First robot arm (second component)

[0068] 8: Actuator

[0069] 13: Lubrication space

[0070] 14, 14': Through hole

[0071] 15: External Space

[0072] 18a, 18b: heat dissipation components

[0073] 19: Threaded hole

[0074] A: First axis (rotation axis)

Claims

1. A joint structure of a robot, characterized in that: include: first component; a second member supported by the first member so as to be rotatable about a horizontal rotation axis relative to the first member; as well as an actuator that drives the second member to rotate the second member relative to the first member, At least one of the first member and the second member is provided with a through hole, the through hole communicating a lubrication space in which a lubrication material of the actuator is sealed with an external space, The number of the through holes is three or more, and the through holes are arranged at intervals in a circumferential direction centered on the horizontal rotation axis; The joint structure of the robot includes a heat dissipation component, and the heat dissipation component is arranged inside and outside the lubrication space using at least one of the through holes.

2. The joint structure of the robot according to claim 1, characterized in that: The through holes are arranged at equal intervals.

3. The joint structure of the robot according to claim 1, characterized in that: The through holes are provided in multiple pairs, Each pair of the through holes is arranged at positions separated by 180° around the horizontal rotation axis.

4. The joint structure of the robot according to any one of claims 1 to 3, characterized in that: The first member is fixed to the installation surface. The through hole is disposed in the first component.

5. The joint structure of a robot according to any one of claims 1 to 3, characterized in that: The through hole is provided in the second member.

6. The joint structure of a robot according to any one of claims 1 to 3, characterized in that: Each through hole is provided with an internal thread.

7. The joint structure of a robot according to any one of claims 1 to 3, characterized in that: The heat dissipating member is provided with a threaded hole that communicates the lubrication space with the external space.

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