Industrial robots

Abstract

An industrial robot is provided that allows easy installation of a gear for rotating a work tool on the robot without requiring backlash adjustment. The robot comprises: a first wrist element rotatable at the front end of a forearm of the robot about a first axis extending along the length of the forearm; a second wrist element rotatable on the first wrist element about a second axis intersecting approximately perpendicularly with the first axis; a third wrist element rotatable on the second wrist element about a third axis extending from the intersection of the first and second axes in a direction approximately perpendicular to the direction in which the second axis extends; a first gear mounted on the third wrist element concentrically with the third axis and rotatable about the third axis; a second gear meshing with the first gear and rotatable in response to the rotation of the first gear; and a housing fixed to the second wrist element, the second gear being mounted on the housing via a bearing so as to be rotatable about a fourth axis disposed a predetermined distance from the third axis.

Description

Technical Field

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

[0002] In industrial robots (hereinafter referred to as "robots"), the following situations are common: a working tool is installed at the front end of the robot's forearm, and a line body including at least one of wiring and piping is used to supply materials such as air or energy or signals such as electricity to the working tool (for example, refer to Patent Document 1).

[0003] The working tool is mounted on the front end of a rotating shaft consisting of a gear (the second gear), which rotates in response to a gear (the first gear) on the rotating shaft disposed at the front end of the robot's forearm. The second gear is offset to the side of the first gear and meshes with the first gear. The linear body passes through a hollow portion arranged along the axis of the second gear and is connected to the working tool. This allows the robot to rotate the second gear, which serves as the final rotating shaft, at high speed in a high-speed visual tracking system or the like.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-7409 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The second gear is installed post-installed to mesh with the first gear pre-installed on the front end of the robot's forearm. However, backlash occurs at the meshing portion of the gears, requiring complex backlash adjustment when installing the second gear post-installed. Therefore, it is desirable to be able to easily install the gear used to rotate the work tool on the robot post-installed without requiring backlash adjustment.

[0009] Solutions for solving problems

[0010] An industrial robot according to one embodiment of the present invention includes: a first wrist element rotatably disposed at a front end of a forearm of the robot about a first axis extending along the longitudinal direction of the forearm; a second wrist element rotatably disposed on the first wrist element about a second axis intersecting approximately perpendicularly with the first axis; a third wrist element rotatably disposed on the second wrist element about a third axis extending from an intersection of the first and second axes in a direction approximately perpendicular to the extension direction of the second axis; a first gear mounted on the third wrist element concentrically with the third axis and rotatable about the third axis; a second gear meshing with the first gear and rotatably disposed in response to rotation of the first gear; and a housing fixed to the second wrist element, the second gear being rotatably mounted on the housing via a bearing about a fourth axis disposed a predetermined distance from the third axis.

[0011] Effects of the Invention

[0012] According to one aspect, an industrial robot can be provided that allows a gear for rotating a working tool to be easily retrofitted to the robot without requiring backlash adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the front view of an industrial robot.

[0014] Figure 2 This is a cross-sectional view of the rotator unit of an industrial robot.

[0015] Figure 3 This is a perspective view illustrating a method for assembling a rotator unit of an industrial robot.

[0016] Figure 4 This is a perspective view illustrating a method for assembling a rotator unit of an industrial robot.

[0017] Figure 5 This is a perspective view illustrating a method for assembling a rotator unit of an industrial robot.

[0018] Figure 6 This is a perspective view illustrating a method for assembling a rotator unit of an industrial robot.

[0019] Figure 7 This is a front view of an industrial robot according to another embodiment. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Figure 1 This is the front view of an industrial robot. Figure 2 2 is a cross-sectional view of a rotator unit of an industrial robot. In the following figures, the Z direction indicated by the arrows indicates the upward direction perpendicular to the floor F on which the robot 1 is installed.

[0021] The robot 1 shown in this embodiment is a six-axis transfer robot controlled by a robot controller (not shown). The robot 1 includes a first wrist element 11, a second wrist element 12, a third wrist element 13, and a rotator unit 2 at the front end of a forearm 10 disposed at the front end of the arm.

[0022] The first wrist element 11 is formed from the front end of the forearm 10 along the longitudinal direction of the forearm 10 ( Figure 1 The first wrist element 11 is configured to be rotatable relative to the forearm 10 around a first axis A1 along the longitudinal direction of the forearm 10.

[0023] The second wrist element 12 is formed in a rectangular box shape and is attached to the front end of the first wrist element 11. The second wrist element 12 is provided to be rotatable relative to the first wrist element 11 around a second axis A2 that intersects substantially perpendicularly with the first axis A1, which is the rotation axis of the first wrist element 11. The second wrist element 12 has a longitudinal direction toward Figure 1 A cylindrical portion 120 protruding downward in the middle.

[0024] The third wrist element 13 comprises a substantially disc-shaped member and is concentrically mounted on the cylindrical portion 120 of the second wrist element 12. The third wrist element 13 is configured to be movable relative to the second wrist element 12 around the intersection of the first axis A1 and the second axis A2 in the direction extending relative to the second axis A2 ( Figure 1 The direction roughly perpendicular to the vertical direction of the paper) Figure 1 The third axis A3 extending in the up and down directions (in the middle) rotates.

[0025] In the present embodiment, “substantially vertical” is not limited to being strictly vertical, and may be slightly inclined relative to the vertical to an extent that does not impair the functions of the second wrist element 12 and the third wrist element 13 .

[0026] like Figure 2 As shown, the first gear 14 is mounted concentrically on the third wrist element 13 with respect to the third axis A3, which is the rotation axis of the third wrist element 13. The first gear 14 has an outer diameter larger than that of the third wrist element 13 and is configured to rotate about the third axis A3. In this embodiment, the first gear 14 is configured as a spur gear. However, the first gear 14 is not limited to a spur gear and may also be a helical gear or the like.

[0027] The rotator unit 2 has a working tool 100, which is mounted on the front end of the second wrist element 12. The working tool 100 is, for example, a claw (Japanese: ハンド), which is arranged on the lower surface of the rotator unit 2 with the aid of a jig. The line body 3 is connected to the working tool 100. The line body 3 includes at least one of piping and wiring for supplying materials such as air or electrical energy or signals for driving the working tool 100 to the line body 3. One end of the line body 3 is connected to the solenoid valve box 4 mounted on the upper part of the forearm 10. One end of the line body 3 passes through the rotator unit 2 and is connected to the working tool 100. In addition, Figure 1 and Figure 2 One linear body 3 is shown. However, there may be multiple linear bodies 3.

[0028] A conduit 5 composed of a flexible tube is provided from the solenoid valve box 4 to the rotator unit 2. In detail, the robot 1 has a first conduit mounting portion 51 arranged near the forearm 10 and a second conduit mounting portion 52 arranged on the side of the rotator unit 2. The vicinity of the forearm 10 where the first conduit mounting portion 51 is arranged refers to an area around the first axis A1 near the forearm 10. Specifically, the first conduit mounting portion 51 of the present embodiment is connected to the solenoid valve box 4 mounted on the upper surface of the forearm 10. The second conduit mounting portion 52 is connected to the second gear 24 described later provided on the rotator unit 2 in a rotatable manner. The conduit 5 is provided across the first conduit mounting portion 51 and the second conduit mounting portion 52. The conduit 5 is installed in a manner that allows rotation relative to at least the second conduit mounting portion 52 of the first conduit mounting portion 51 and the second conduit mounting portion 52. The linear body 3 passes through the interior of the conduit 5 and extends from the solenoid valve box 4 to the working tool 100.

[0029] like Figure 2 As shown, the rotator unit 2 includes a metal housing 20. The housing 20 is fixed to the cylindrical portion 120 of the second wrist element 12. The lower portion of the housing 20 is largely open, and the housing 20 protrudes significantly laterally from the cylindrical portion 120 of the second wrist element 12 in a direction substantially perpendicular to the third axis A3.

[0030] The housing 20 has a first opening 21 that opens upward in a circular shape. The first opening 21 is concentric with the third axis A3. The first opening 21 has an opening diameter that is smaller than the outer diameter of the cylindrical portion 120 of the second wrist element 12 but larger than the outer diameter of the third wrist element 13. When the housing 20 is fixed to the cylindrical portion 120 of the second wrist element 12, the first opening 21 surrounds the radially outer side of the third wrist element 13.

[0031] A fitting portion 22 formed of a stepped portion is provided on the outer side of the first opening 21. The fitting portion 22 has an inner diameter larger than the opening diameter of the first opening 21 and is provided to surround the first opening 21 on the upper surface of the housing 20. The first opening 21 is provided to open concentrically with the bottom of the fitting portion 22. The inner diameter of the fitting portion 22 is substantially equal to the outer diameter of the cylindrical portion 120 of the second wrist element 12. The housing 20 is mounted on the second wrist element 12 by fitting the fitting portion 22 with the outer circumference of the cylindrical portion 120 of the second wrist element 12 and is secured to the cylindrical portion 120 of the second wrist element 12 by a plurality of bolts 200. Thus, since the housing 20 is mounted by fitting the fitting portion 22 with the cylindrical portion 120 of the second wrist element 12, positioning of the housing 20 is facilitated, simplifying the assembly of the rotator unit 2.

[0032] The upper surface of the housing 20 has a raised portion 20a located to the side of the first opening 21, which is raised upward along the third axis A3 relative to the fitting portion 22. The raised portion 20a of the housing 20 has a second opening 23 that opens upward in a circular shape. The fourth axis A4, which serves as the central axis of the second opening 23, is spaced a predetermined distance from the fitting portion 22 with a predetermined tolerance. The fourth axis A4 extends approximately parallel to the third axis A3, which serves as the central axis of the first opening 21.

[0033] A second gear 24, serving as the final rotation axis of the robot 1, is mounted within the housing 20 within the second opening 23. This second gear 24 meshes with the first gear 14. The second gear 24 includes a cylindrical portion 240 and a toothed portion 242 disposed on the outer periphery of the cylindrical portion 240. Furthermore, the cylindrical portion 240 includes a hollow portion 241 disposed along the fourth axis A4. The second gear 24 is mounted within the second opening 23 via an appropriate number of bearings 25 disposed within the inner periphery of the second opening 23.

[0034] The housing 20 is sealed by a cover 26 while housing the first gear 14 and the second gear 24 along with a lubricant such as grease. The cover 26 is secured to the lower end of the housing 20 (as shown) by a plurality of bolts 201. By housing the first gear 14 and the second gear 24 along with the lubricant in the housing 20, wear of the first gear 14 and the second gear 24 is suppressed.

[0035] The cover 26 has a circular opening 260. The front end surface 243 of the cylindrical portion 240 of the second gear 24 passes through the opening 260 and is exposed to the outside of the cover 26. The front end surface 243 of the cylindrical portion 240 constitutes the working tool 100 (in Figure 2 Mounting surface (not shown).

[0036] The cylindrical portion 240 of the second gear 24 protrudes upward from the second opening 23 of the housing 20. The second conduit mounting portion 52 is connected to the cylindrical portion 240 protruding upward from the second opening 23. As a result, the interior of the conduit 5 and the hollow portion 241 are connected. The filament body 3 passing through the conduit 5 is guided from the solenoid valve box 4 mounted on the forearm 10 to the working tool 100 via the hollow portion 241. Therefore, the filament body 3 is led out in a direction opposite to the direction in which the second wrist element 12 directs the front end portion of the working tool 100 directly downward.

[0037] The guide tube 5 extends along the side of the first wrist element 11, between the first guide tube mounting portion 51 and the second guide tube mounting portion 52, on the side opposite to the front end of the working tool 100, and is arranged so as not to contact the body of the robot 1. This allows the umbilical member 3 to be stably mounted relative to the robot 1.

[0038] The second opening 23 of the housing 20, for mounting the second gear 24, is located in the raised portion 20a of the housing 20. The rear end surface 244 of the hollow portion 241 of the second gear 24 protrudes upward from the second opening 23. Therefore, the second conduit mounting portion 52, connected to the hollow portion 241 of the second gear 24, is located closer to the second wrist element 12 than the third wrist element 13, relative to the fixed portion between the fitting portion 22 of the housing 20 and the cylindrical portion 120 of the second wrist element 12. Consequently, the connection between the second gear 24 and the second conduit mounting portion 52 is located closer to the second wrist element 12 than the third wrist element 13. As a result, the second conduit mounting portion 52 can be easily mounted to the hollow portion 241 of the second gear 24.

[0039] Furthermore, the connection between the raised portion 20a of the housing 20 and the second gear 24 and the second conduit mounting portion 52 is arranged in the space S to the side of the cylindrical portion 120 of the second wrist element 12. This allows the raised portion 20a and the connection between the second gear 24 and the second conduit mounting portion 52 to be closer to the second wrist element 12. Consequently, the rotator unit 2 can be constructed in a compact manner.

[0040] Furthermore, since the second opening 23, to which the second gear 24 is mounted, is disposed in the raised portion 20a of the housing 20, the second opening 23 can rotatably support the second gear 24 via the bearing 25 over a relatively long distance along the extending direction of the fourth axis A4. Therefore, the second gear 24 can rotate stably.

[0041] Next, refer to Figures 3 to 6 The following describes an assembly method for mounting the rotator unit 2 relative to the second wrist element 12. Figures 3 to 6Only the second wrist element 12, the third wrist element 13, and the rotator unit 2 of the robot 1 are shown. Figures 3 to 6 In the embodiment, the second wrist element 12, the third wrist element 13 and the rotator unit 2 are relative to Figure 1 and Figure 2 The diagram is shown upside down.

[0042] First, if Figure 3 As shown, the first opening 21 of the housing 20 of the rotator unit 2 is concentrically mounted to the cylindrical portion 120 of the second wrist element 12 to which the third wrist element 13 is mounted, via an O-ring 202. Specifically, the housing 20 is mounted to the cylindrical portion 120 by engaging the fitting portion 22 of the housing 20, which is concentrically arranged with the first opening 21. At this time, the second gear 24 is pre-mounted in the housing 20 via the bearing 25 (in the Figure 3 The housing 20 mounted on the cylindrical portion 120 is fixed to the cylindrical portion 120 by a plurality of bolts 200.

[0043] Then, if Figure 4 As shown, the first gear 14 is concentrically mounted on the third wrist element 13 disposed within the housing 20 and secured to the third wrist element 13 by a plurality of bolts 203. The fourth axis A4, which represents the central axis of the second gear 24, is positioned a predetermined distance from the fitting portion 22 of the housing 20, with a predetermined tolerance. The predetermined distance refers to the distance within the housing 20 at which the second gear 24 is positioned so that the teeth 242 of the second gear 24 properly mesh with the teeth of the first gear 14. Therefore, when the first gear 14 is mounted on the third wrist element 13, the first and second gears 14 and 24 are configured to mesh with each other.

[0044] Next, the interior of the housing 20 to which the first gear 14 and the second gear 24 are mounted is filled with a lubricant such as grease. Figure 5 As shown, the cover 26 is mounted on the housing 20 via a gasket 204 and fixed to the housing 20 by a plurality of bolts 201. The front end surface 243 of the cylindrical portion 240 of the second gear 24 is exposed to the outside of the housing 20 through the opening 260 of the cover 26.

[0045] For the rotator unit 2 in which the housing 20 is closed by the cover 26, as shown in FIG. Figure 6 As shown, a jig 101 is attached to the second gear 24 via an oil seal 102. A working tool 100 is attached to the jig 101. Thus, the robot 1 is provided with the working tool 100 that rotates in response to the rotation of the third wrist element 13.

[0046] The housing 20 of the rotator unit 2 is positioned and mounted on the cylindrical portion 120 of the second wrist element 12 by engaging the engaging portion 22. Inside the housing 20, the second gear 24, which meshes with the first gear 14 and rotates driven by the first gear 14, is mounted in a second opening 23, which is arranged at a predetermined distance from the third axis A3, the rotation axis of the first gear 14, at a predetermined intersection, so as to be rotatable about the fourth axis A4. Thus, simply by mounting the first gear 14 on the third wrist element 13, the first gear 14 and the second gear 24, which is pre-mounted on the housing 20, can be properly positioned and meshed. Therefore, there is no need to adjust the backlash after mounting the two gears, and the rotator unit 2 can be easily mounted on the front end of the forearm 10 of the robot 1.

[0047] In the embodiment described above, the catheter 5 extends along the first axis A1 outside the first wrist element 11 and is connected to the solenoid valve box 4 installed on the upper part of the forearm 10. Figure 7 As shown, the catheter 5 can also be passed through the hollow hole 10a provided in the forearm 10. The hollow hole 10a is provided concentrically with the first axis A1 passing through the center of the forearm 10. In the first wrist element 11, a connecting hole 11a connected to the hollow hole 10a of the forearm 10 is provided from the connection end connected to the forearm 10 to the middle of the first wrist element 11. The catheter 5 extends along the first axis A1 inside the hollow hole 10a of the forearm 10 and inside the connecting hole 11a of the first wrist element 11. The first catheter mounting portion 51 is arranged at the rear portion 10b of the forearm 10 and extends rearward from the rear portion 10b. The catheter 5, which exits the connecting hole 11a and extends toward the front end of the first wrist element 11, is curved in an arc shape along the direction around the second axis A2 and is connected to the rotator unit 2 using the second catheter mounting portion 52.

[0048] By disposing the catheter 5 in this manner, with the above-mentioned characteristics, the behavior of the catheter 5 during operation of the first wrist element 11 can be stabilized while maintaining the minimum curvature radius of the catheter 5 around the second axis A2.

[0049] Description of Reference Numerals

[0050] 1. Industrial robot; 10. Forearm; 10a. Hollow hole; 10b. Rear portion; 11. First wrist element; 12. Second wrist element; 13. Third wrist element; 14. First gear; 20. Housing; 22. Fitting portion; 24. Second gear; 241. Hollow portion; 25. Bearing; 3. Linear body; 5. Conduit; 51. First conduit mounting portion; 52. Second conduit mounting portion; 100. Working tool; A1. First axis; A2. Second axis; A3. Third axis; A4. Fourth axis.

Claims

1. An industrial robot, wherein: The industrial robot includes: a first wrist element, which is provided at the front end of the forearm of the robot and is capable of rotating about a first axis along the length direction of the forearm; a second wrist element, provided on the first wrist element and capable of rotating about a second axis that intersects the first axis substantially perpendicularly; a third wrist element mounted on a front end surface of a cylindrical portion provided at a front end of the second wrist element and rotatable about a third axis extending from an intersection of the first axis and the second axis in a direction substantially perpendicular to an extending direction of the second axis; a first gear mounted on the third wrist element so as to be concentrically fitted with the third axis and rotatable about the third axis; a second gear meshing with the first gear so as to be rotatable following rotation of the first gear; and a housing fixed to the second wrist element, The housing has: a first opening portion, which is configured to surround the outer side of the third wrist element; a fitting portion provided outside the first opening in a concentric manner with the first opening and having an inner diameter larger than an opening diameter of the first opening; a raised portion that is raised laterally from the fixed portion of the second wrist element and extends in a direction in which the second wrist element extends relative to the housing, relative to the fixed portion; and a second opening that passes through the raised portion and has a fourth axis as its central axis and is disposed substantially parallel to the third axis at a predetermined distance; The second gear is mounted on the second opening of the housing via a bearing so as to be rotatable about a fourth axis, and is disposed in the housing at a predetermined distance from the fitting portion. The first gear and the second gear are positioned by fitting the outer periphery of the cylindrical portion of the second wrist element into the fitting portion.

2. The industrial robot according to claim 1, wherein: The housing accommodates the first gear and the second gear together with lubricant therein.

3. The industrial robot according to claim 1 or 2, wherein: The second gear has a hollow portion along the fourth axis, and a working tool is mounted on the front end of the second gear. The industrial robot further comprises: a ramid including at least one of a wiring and a pipe connected to the working tool; a flexible conduit for the umbilical cord to pass through, guiding the umbilical cord from the forearm through the hollow portion to the working tool; a first catheter mounting portion, disposed near the forearm; and a second conduit mounting portion connected to the second gear, The umbilical body is led out through the second guide tube mounting portion in a direction opposite to the direction in which the second wrist element directs the front end of the working tool directly downward. One end of the conduit is mounted on the first conduit mounting portion, and the other end of the conduit is mounted on the second conduit mounting portion. The guide tube extends along the first wrist element between the first guide tube mounting portion and the second guide tube mounting portion, on the side of the first wrist element opposite to the front end portion of the working tool, and is arranged so as not to contact the body of the robot. At least the other end of the pipe is rotatably mounted on the second pipe mounting portion.

4. The industrial robot according to claim 3, wherein: The second catheter mounting portion is arranged closer to the second wrist element than the third wrist element with respect to a fixing portion between the housing and the second wrist element.

5. The industrial robot according to claim 3, wherein: The catheter passes through the hollow hole provided in the forearm, The first catheter mounting portion is disposed on the rear portion of the forearm.

6. The industrial robot according to claim 4, wherein: The catheter passes through the hollow hole provided in the forearm, The first catheter mounting portion is disposed on the rear portion of the forearm.

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