Articulated robot

Abstract

To save a space around a swiveling portion of an articulated robot.SOLUTION: An articulated robot 1 comprises: a robot arm 10 having a plurality of joints; a swiveling portion 2 having a support face 26 which supports the robot arm 10; a speed reducer 3 which is positioned above or below the support face 26 along a first axis O1 extending in a vertical direction, and swivels the swiveling portion 2 around the first axis O1; and a motor 4 having a shaft 41 which rotates around a second axis O2 shifted from the first axis O1 in a horizontal direction and is connected to the speed reducer 3, and a case 42 which houses the shaft 41 and is supported by the swiveling portion 2, and in which the case 42 is positioned on a side same as the speed reducer 3 in the vertical direction with respect to the support face 26.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed herein relates to an articulated robot. [Background technology]

[0002] Patent Document 1 discloses an example of a multi-joint robot. The multi-joint robot disclosed in Patent Document 1 includes a first arm, a second arm, a third arm, a rotating unit, and an actuator. The first arm, the second arm, and the third arm are connected in series to each other. The rotating unit is connected to a base end of the first arm. The actuator rotates the rotating unit around a vertical axis. The actuator is composed of, for example, an electric motor, a reducer, and a brake. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5975129 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of an articulated robot such as that disclosed in Patent Document 1, it is possible to place an actuator near the axis of the rotating part. However, if the actuator is placed on a vertical axis, the dimensions around the rotating part may be longer in the vertical direction compared to when the actuator is placed in another location. The longer dimensions are inconvenient in terms of saving space around the rotating part. [Means for solving the problem]

[0005] The technology disclosed herein relates to an articulated robot, which includes a robot arm having multiple joints, a rotating part having a support surface that supports the robot arm, a reducer located above or below the rotating part along a first axis extending in a vertical direction and rotating the rotating part about the first axis, a shaft that rotates about a second axis that is horizontally shifted from the first axis and is connected to the reducer, and a case that houses the shaft and is supported by the rotating part, the case being located on the same side as the reducer in the vertical direction with respect to the support surface. Effect of the Invention

[0006] According to the articulated robot, the space around the rotating part can be saved. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a side view of an articulated robot. [Diagram 2] FIG. 2 is a vertical cross-sectional view of the swivel portion. [Diagram 3] FIG. 3 is a view corresponding to FIG. 1 of an articulated robot according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of an articulated robot will be described. The following embodiment is merely an example.

[0009] (Overall composition) FIG. 1 is a side view of a multi-joint robot 1. The multi-joint robot 1 is used, for example, in the field of logistics. Specifically, the multi-joint robot 1 illustrated in FIG. 1 can be used for loading and unloading goods. The use of the multi-joint robot 1 is not limited to the field of logistics. The multi-joint robot 1 is installed on an installation surface F. In other words, the installation surface F supports the multi-joint robot 1 from below. The installation surface F may be the floor surface of a loading and unloading area for goods, a factory, etc.

[0010] In the following description, the up-down direction refers to the height direction of the articulated robot 1, as shown by the double-headed arrow D1 in Fig. 1. The up-down direction corresponds to the up-down direction on the paper surface of Fig. 1. Similarly, the horizontal direction in the following description refers to the direction perpendicular to the up-down direction, as shown by the double-headed arrow D2 in Fig. 1. The horizontal direction corresponds to the left-right direction on the paper surface of Fig. 1.

[0011] As shown in FIG. 1, the articulated robot 1 includes a robot arm 10, a rotating unit 2, a reducer 3, a motor 4, and a first base 5. The robot arm 10 has a plurality of joints. The rotating unit 2 has a support surface 26 that supports the robot arm 10. The reducer 3 rotates the rotating unit 2 around a first axis O1. As described later, the first axis O1 is an axis that extends in the vertical direction. The motor 4 supplies power to the rotating unit 2 via the reducer 3. The first base 5 is interposed between the installation surface F and the rotating unit 2 in the vertical direction. Note that the first base 5 is not an essential element of the articulated robot 1.

[0012] When used for loading and unloading articles, the articulated robot 1 may utilize a so-called transport conveyor C. The transport conveyor C extends, for example, to directly above the swivel unit 2. The articulated robot 1 and the transport conveyor C constitute a transport system for transporting articles.

[0013] The robot arm 10 includes a second base 11. The second base 11 is a base end of the robot arm 10. The second base 11 includes a base body 111 and a support portion 112. The base body 111 has a flat upper surface. The support portion 112 is fixed to the upper surface of the base body 111. Note that the second base 11 is not essential.

[0014] The robot arm 10 also includes a robot hand 12 as an end effector. The robot hand 12 is the tip of the robot arm 10. The robot hand 12 grasps an object to be loaded or unloaded. Note that the end effector of the robot arm 10 is not limited to the robot hand 12.

[0015] The robot arm 10 is a seven-axis vertically articulated robot arm. Specifically, the robot arm 10 includes joints JT1-JT7. The joints JT1-JT7 are connected in series from the base end to the tip end.

[0016] The joint JT1 connects the rotating part 2 and the second base 11. The joint JT1 rotates the second base 11 around a first joint axis Ax1. By rotating the second base 11, the entire robot arm 10 rotates around the first joint axis Ax1. The first joint axis Ax1 is an axis perpendicular to the installation surface F. Note that the first joint axis Ax1 is not essential.

[0017] The joint JT2 is a joint that connects the second base 11 and the first link 61. The first link 61 is an arm that connects the joint JT2 to a joint JT3 described later. The first link 61 rotates relatively to the second base 11 around a second joint axis Ax2. The second joint axis Ax2 is a horizontal axis that is parallel to the installation surface F. The second joint axis Ax2 is perpendicular to the first joint axis Ax1.

[0018] The joint JT3 is a joint that connects the first link 61 and the second link 62. The second link 62 is an arm that connects the joint JT3 and a joint JT4 described below. The second link 62 rotates relatively to the first link 61 around a third joint axis Ax3. The third joint axis Ax3 is an axis parallel to the second joint axis Ax2.

[0019] The joint JT4 is a joint that connects the second link 62 and the third link 63. The third link 63 is an arm that connects the joint JT4 and a joint JT5 described later. The third link 63 rotates relative to the second link 62 around a fourth joint axis Ax4. The fourth joint axis Ax4 is an axis parallel to the second joint axis Ax2.

[0020] The joint JT5 is a joint that connects the third link 63 and the fourth link 64. The fourth link 64 is an arm to which the robot hand 12 is connected. The fourth link 64 rotates relative to the third link 63 about a fifth joint axis Ax5. The fifth joint axis Ax5 is an axis parallel to the second joint axis Ax2.

[0021] The sixth joint JT6 is a joint that rotates the third link 63. More specifically, the sixth joint JT6 rotates the third link 63 about a sixth joint axis Ax6. The sixth joint axis Ax6 is an axis perpendicular to the second joint axis Ax2.

[0022] The joint JT7 is a joint that rotates the fourth link 64. More specifically, the seventh joint JT7 rotates the fourth link 64 about a seventh joint axis Ax7. The seventh joint axis Ax7 is an axis perpendicular to the second joint axis Ax2.

[0023] The movement of the first joint JT1 is powered by the actuator 13 shown in Fig. 1. The actuator 13 is fixed to the upper surface of the base body 111, similar to the support part 112. The actuator 13 is aligned with the support part 112 in the horizontal direction.

[0024] The actuator 13 is an electric motor. The shaft of the electric motor rotates about a rotation axis Oa. The rotation axis Oa of the shaft is perpendicular to the installation plane F. The electric motor may be a servo motor or a step motor.

[0025] The actuator 13 operates based on an electrical signal input from the controller 100. The controller 100 is electrically connected to the actuator 13. The controller 100 includes a processor, a memory, and an input / output bus. The controller 100 generates an electrical signal.

[0026] The swivel unit 2 is a link member that connects the first base 5 and the second base 11. The link member as the swivel unit 2 extends in the horizontal direction. As described later, the swivel unit 2 can also be regarded as an arm extending in the horizontal direction.

[0027] In addition, the swivel unit 2 has a first end 21 and a second end 22. The first end 21 connects the swivel unit 2 to the first base 5. The first end 21 is a base end of the swivel unit 2. The second end 22 supports the second base 11. The second end 22 is a tip end of the swivel unit 2. The first end 21 and the second end 22 are separated in the horizontal direction. As shown in FIG. 1, the first joint axis Ax1 passes through the second end 22.

[0028] The swivel unit 2 can rotate relative to the first base 5. That is, the articulated robot 1 can also be called an eight-axis robot in which, in addition to the joints JT1-JT7, the connection between the swivel unit 2 and the first base 5 is regarded as an eighth joint JT8.

[0029] Specifically, the joint JT8 rotates the swivel unit 2 relatively to the first base 5 around a first axis O1. The first axis O1 is an axis extending in the vertical direction. For example, the first axis O1 is perpendicular to the installation surface F. The first axis O1 is also shifted in the horizontal direction with respect to the first joint axis Ax1. More specifically, the first axis O1 is closer to the first end 21 of the swivel unit 2 than the first joint axis Ax1 is in the horizontal direction. More specifically, the first axis O1 passes through the first end 21.

[0030] The operation of the joint JT8 is powered by a motor 4 shown in Fig. 1. Power output from the motor 4 drives the joint JT8 via a reduction gear 3. The reduction gear 3 and the motor 4 are supported by a rotating part 2. Although details will be described later, the motor 4 has a shaft 41 and a case 42. The shaft 41 is an output shaft of the motor 4. The case 42 is a main body that houses the shaft 41.

[0031] (Details of the first base 5, the rotating part 2, the reducer 3, and the motor 4) Hereinafter, the first base 5, the rotating part 2, the reducer 3, and the motor 4 will be described in detail with reference to Fig. 2. Fig. 2 is a vertical cross-sectional view of the rotating part 2. The vertical cross-sectional view of Fig. 2 shows the structure around the joint JT8 in the rotating part 2. The double-headed arrow D1 in Fig. 2 indicates the up-down direction as in Fig. 1. The double-headed arrow D2 in Fig. 2 indicates the horizontal direction as in Fig. 1.

[0032] -First Base 5- 2, the first base 5 supports the first end 21 of the swivel unit 2 from below.

[0033] Here, the base 51 is a hollow base having a cylindrical shape. The base 51 is placed on an installation surface F. In other words, the installation surface F supports the base 51 from below. The base 51 supports the connecting plate 52 from below.

[0034] The connecting plate 52 is an annular plate-like body. The connecting plate 52 is fixed to the upper surface of the base 51. The connecting plate 52 supports the first end 21 from below. Note that it is not essential that the base 51 and the connecting plate 52 are separate bodies. The base 51 and the connecting plate 52 may be integrated.

[0035] -Rotating part 2- The rotating part 2 is a hollow arm extending from a first end 21 to a second end 22. A reducer 3 is located at the first end 21 along a first axis O1. A robot arm 10 is located at the second end 22 along a first joint axis Ax1. Specifically, the rotating part 2 includes an arm body 23, a first cover 24, a second cover 25, and a support surface 26.

[0036] Here, the arm body 23 is an arm that extends horizontally and has an open upper surface. The arm body 23 extends horizontally from the first end 21 to the second end 22. The arm body 23 constitutes the side surface 2s and the lower surface 2u of the rotating part 2.

[0037] The arm body 23 has a through hole 23a extending in the up-down direction. Specifically, the through hole 23a according to this embodiment penetrates the lower surface 2u of the swivel part 2. The through hole 23a is horizontally spaced apart from the first end 21. More specifically, the through hole 23a is horizontally spaced apart from both the first end 21 and the second end 22. Furthermore, the case 42 of the motor 4 passes through the through hole 23a. The inner diameter of the through hole 23a is sized to allow the case 42 to pass through.

[0038] The first cover 24 is a plate-shaped member extending horizontally. The first cover 24 closes the open portion of the arm body 23. The first cover 24 forms the upper surface of the rotating part 2. The first cover 24 is fixed to the arm body 23. The first cover 24 can be removed from the arm body 23 as necessary.

[0039] The second cover 25 is a plate-like member extending in the horizontal direction. The second cover 25 is located inside the arm body 23. More specifically, the second cover 25 is disposed between the first cover 24 and the lower surface 2u in the vertical direction. The second cover 25 is fixed inside the arm body 23. The second cover 25 can be removed from the arm body 23 as necessary. The second cover 25 has an opening 25a that passes through the second cover 25 in the vertical direction. As shown in FIG. 2, the first axis O1 passes through the opening 25a.

[0040] Further, the second cover 25 divides the internal space of the swivel unit 2 into upper and lower spaces. Specifically, a first storage space S1 for storing the cable 8 is defined between the first cover 24 and the second cover 25. A second storage space S2 for storing the belt 7 is defined between the second cover 25 and the lower surface 2u. The first storage space S1 and the second storage space S2 communicate with each other through the opening 25a. Note that the second cover 25, and therefore the first storage space S1, are not essential.

[0041] The upper surface of the rotating unit 2 constitutes a support surface 26. The support surface 26 supports the robot arm 10. More specifically, the support surface 26 supports the robot arm 10 from below. For example, the support surface 26 may be the upper surface of a portion of the rotating unit 2 that includes the second end 22. The support surface 26 may be the upper surface of the first cover 24, or another surface parallel to the upper surface of the first cover 24.

[0042] -Reducer 3- 2, the reducer 3 is located below the support surface 26 along the first axis O1. More specifically, the reducer 3 is located below the first cover 24 along the first axis O1. More specifically, the reducer 3 is located below the second cover 25 and above the first base 5 along the first axis O1. As described above, the reducer 3 causes the swivel unit 2 to swivel about the first axis O1.

[0043] The reducer 3 is a cycloid gear reducer having a hollow structure. However, it is not essential that the reducer 3 is a cycloid gear reducer. The reducer 3 may be, for example, a planetary gear device or a wave gear device. It is also not essential that the reducer 3 is hollow.

[0044] Specifically, the reducer 3 according to this embodiment has a support shaft 31, a hollow tube 32, a first pulley 33, a reduction mechanism 34, and a case 35. The reducer 3 reduces the rotation input to the first pulley 33 by the reduction mechanism 34. The reducer 3 inputs the reduced rotation to the swivel section 2 via the case 35.

[0045] Here, the support shaft 31 is a hollow member having a cylindrical shape. The support shaft 31 is fixed to the upper surface of the connecting plate 52. The reducer 3 is supported by the first base 5 via the support shaft 31.

[0046] The hollow tube 32 has a cylindrical shape coaxial with the first axis O1. The lower end of the hollow tube 32 is inserted into the support shaft 31. The upper end of the hollow tube 32 is inserted into the first pulley 33 and the reduction gear mechanism 34. The cable 8 is inserted through the hollow tube 32. The cable 8 is pulled out into the first housing space S1 through the opening 25a.

[0047] The first pulley 33 rotates relative to the support shaft 31 and the hollow tube 32, centering on the first axis O1. A belt 7 is wound around the first pulley 33. The belt 7 connects the shaft 41 of the motor 4 to the first pulley 33 of the speed reducer 3. Power output from the shaft 41 is transmitted to the first pulley 33 via the belt 7. The first pulley 33 rotates in response to the transmitted power.

[0048] The reduction mechanism 34 is a gear mechanism having a crankshaft and a pinion. The reduction mechanism 34 is connected to the first pulley 33 and the case 35. When the first pulley 33 rotates, the reduction mechanism 34 rotates the case 35 at a rotation speed slower than that of the first pulley 33.

[0049] The case 35 rotates about the first axis O1 relative to the support shaft 31 and the hollow tube 32. The case 35 is fixed to the rotating part 2, particularly to the lower surface 2u of the arm body 23. The case 35 and the rotating part 2 operate integrally.

[0050] -Motor 4- As shown in Fig. 2, the motor 4 is located below the support surface 26. More specifically, the motor 4 is located below the first cover 24. More specifically, the motor 4 is located below the second cover 25. In addition, in the horizontal direction, the motor 4 is aligned with the reducer 3 along the longitudinal direction of the rotating part 2. As described above, the motor 4 drives the joint JT8 via the reducer 3.

[0051] The motor 4 is an electric motor. The electric motor serving as the motor 4 may be a servo motor or a step motor. The motor 4 is electrically connected to the above-mentioned controller 100. The motor 4 operates based on an electric signal input from the controller 100.

[0052] Specifically, as described above, the motor 4 according to this embodiment has the shaft 41 as an output shaft and the case 42 as a main body. The shaft 41 is the output shaft of the motor 4. The case 42 is the main body that houses the shaft 41. The motor 4 rotates the shaft 41 relative to the case 42 based on an electrical signal input from the controller 100.

[0053] The shaft 41 rotates around a second axis O2 and is connected to the reducer 3. The second axis O2 is an axis parallel to the first axis O1. In other words, the second axis O2 is an axis horizontally shifted from the first axis O1. More specifically, the second axis O2 is horizontally shifted from both the first axis O1 and the first joint axis Ax1. More specifically, the second axis O2 is closer to the first axis O1 than the first joint axis Ax1 in the horizontal direction. In other words, the second axis O2 is closer to the first end 21 than the second end 22 in the horizontal direction. The second axis O2 extends in the up-down direction. For example, the second axis O2 is perpendicular to the installation surface F. The second axis O2 is parallel to the first axis O1 and the first joint axis Ax1.

[0054] The shaft 41 is connected to the first pulley 33 as described above. Specifically, the shaft 41 has a first end 41a and a second pulley 41b. The first end 41a protrudes upward from the case 42. The first end 41a is the upper end of the shaft 41 in this embodiment. The second pulley 41b is located at the first end 41a. The shaft 41 is housed in the shaft 41 except for the first end 41a and the second pulley 41b. The belt 7 is wound around the second pulley 41b. The belt 7 connects the second pulley 41b to the first pulley 33. The first end 41a and the second pulley 41b are aligned with the first pulley 33 in the horizontal direction as shown in FIG. 2. The first pulley 33, the first end 41a, and the second pulley 41b are located in the second housing space S2, similar to the belt 7.

[0055] The case 42 houses the shaft 41 and is supported by the swivel section 2. In addition, the case 42 is located on the same side as the reducer 3 in the up-down direction with respect to the support surface 26. In this embodiment, the case 42 is located on the lower side with respect to the support surface 26, that is, below the support surface 26. More specifically, the case 42 is located below the first cover 24. More specifically, the case 42 is located below the second cover 25.

[0056] In addition, the case 42 protrudes downward from the rotating part 2. Specifically, the case 42 protrudes downward from the lower surface 2u of the rotating part 2. More specifically, the case 42 protrudes downward through the through-hole 23a of the arm body 23.

[0057] The case 42 is connected to the swivel unit 2 via a mounting plate 43. The mounting plate 43 is a plate-shaped member that is not large enough to pass through the through hole 23a. The mounting plate 43 is fixed to the case 42. The mounting plate 43 fixed to the case 42 forms a flange of the case 42. The case 42 is inserted into the through hole 23a from above with the mounting plate 43 fixed. The mounting plate 43 and the arm body 23 are fastened to each other by a fastener 44 inserted from above. The fastener 44 is, for example, a bolt. The case 42 is fastened to the periphery of the through hole 23a via the mounting plate 43. The mounting plate 43 functions as a retainer that prevents the case 42 from falling out of the through hole 23a. Note that the connection of the case 42 using the mounting plate 43 is not essential. Note that the case 42 and the mounting plate 43 may be integral.

[0058] (Regarding the operation of the rotating part) The controller 100 inputs an electric signal to the motor 4. The shaft 41 rotates in response to the electric signal. The rotation of the shaft 41 is input to the first pulley 33 via the belt 7. The first pulley 33 rotates in response to the input from the belt 7. The reduction mechanism 34 rotates the case 35 at a rotation speed slower than that of the first pulley 33. The case 35 rotates integrally with the arm body 23 and thus the rotating unit 2. The rotating unit 2 rotates relatively to the first base 5 around the first axis O1. As the rotating unit 2 rotates, the robot arm 10 supported on the second end 22 of the rotating unit 2 also rotates.

[0059] 2, the motor 4 is supported by the swivel unit 2. In this way, when the swivel unit 2 rotates, the motor 4 rotates integrally with the swivel unit 2 about the first axis O1.

[0060] (Regarding the space around the turning part) In the case of a conventional articulated robot, the motor of the rotating part that rotates around a vertical axis is generally fixed to a base that supports the rotating part near the axis. Therefore, in the articulated robot 1, it is conceivable to place the motor 4 near the first axis O1 of the rotating part 2. However, if the motor 4 is placed on the vertical first axis O1, the dimensions around the rotating part 2 may be longer in the vertical direction compared to cases where other layouts are adopted. The longer dimensions are inconvenient in terms of saving space around the rotating part 2.

[0061] For example, as a first method, it is possible to insert the motor 4 into the first base 5 from above at the first end 21 of the swivel part 2. In this case, the first base 5, the reducer 3, and the motor 4 are aligned in the vertical direction, so the periphery of the first end 21 becomes longer in the upward direction compared to the case where other layouts are adopted. Being longer in the upward direction is inconvenient because it may cause interference with the transport conveyor C, etc.

[0062] Therefore, as a second method for making the periphery of the swivel unit 2 compact, it is possible to insert the motor 4 into the first base 5 from below at the first end 21 of the swivel unit 2. The motor 4 inserted from below is housed in, for example, the pedestal 51 of the first base 5. However, when the second method is applied, it is necessary to turn the first base 5, and in turn the entire articulated robot 1 upside down when replacing the motor 4. Turning the entire articulated robot 1 upside down is time-consuming. The occurrence of such time-consuming work is inconvenient for efficient maintenance of the articulated robot 1.

[0063] As a third method for laying out the motor 4 in a location other than the first end 21, it is possible to place the motor 4 on the base body 111 of the second base 11. However, in order to place the motor 4 on the base body 111, it is necessary to make the upper surface of the base body 111 wider. Enlarging the base body 111 is inconvenient in terms of making the articulated robot 1 space-saving.

[0064] On the other hand, if the swivel unit 2 and the motor 4 rotate integrally as in this embodiment, interference between the swivel unit 2 and the motor 4 is suppressed. Furthermore, if the reducer 3 is disposed below the swivel unit 2, space is created to the side of the reducer 3 depending on the vertical dimension of the reducer 3. Therefore, in this embodiment, the motor 4 supported by the swivel unit 2 is disposed in the space to the side of the reducer 3, thereby saving space around the swivel unit 2.

[0065] Specifically, in the articulated robot 1 according to this embodiment, the first axis O1 of the reducer 3 and the second axis O2 of the motor 4 are offset in the horizontal direction as illustrated in Fig. 1. In addition, the reducer 3 and the case 42 of the motor 4 are located on the same side with respect to the support surface 26.

[0066] That is, the motor 4 according to this embodiment is located to the side of the reducer 3. Therefore, the space created to the side of the reducer 3 is utilized without waste. Utilizing the space makes the area around the revolving unit 2 more compact in the vertical direction. By making the area more compact in the vertical direction, the space around the revolving unit 2 can be saved.

[0067] Furthermore, since the rotating unit 2 supports the motor 4 as in this embodiment, the rotating unit 2 and the motor 4 rotate integrally. The integral rotation reduces interference between the rotating unit 2 and the motor 4. The articulated robot 1 according to this embodiment can simultaneously save space around the rotating unit 2 and reduce interference between the rotating unit 2 and the motor 4.

[0068] 1, in the articulated robot 1 according to this embodiment, the reducer 3 is located below the support surface 26. In addition, the motor 4 protrudes downward from the support surface 26.

[0069] That is, the reducer 3 and the motor 4 according to this embodiment are located on the opposite side of the transport conveyor C across the swivel unit 2. This makes it possible to suppress interference between the reducer 3 and the motor 4 and the transport conveyor C. The end of the transport conveyor C can be extended close to the robot arm 10.

[0070] As illustrated in FIG. 2, the swivel portion 2 according to this embodiment is provided with a through hole 23a that extends in the vertical direction and through which the case 42 of the motor 4 passes.

[0071] The motor 4 according to this embodiment can be removed upward from above, and can be fixed without inserting it into the rotating unit 2 from below. By eliminating the need to insert it from below, there is no need to turn the rotating unit 2 upside down when attaching and removing the motor 4. By eliminating the need to invert the rotating unit 2, the motor 4 can be easily attached and removed. By facilitating the attachment and removal of the motor 4, the articulated robot 1 can be efficiently maintained.

[0072] In the articulated robot 1 according to this embodiment, the shaft 41 is connected to the reducer 3 via a belt 7, as illustrated in FIG.

[0073] If the motor 4 and the reducer 3 were connected via gears, multiple gears would have to be used to separate the motor 4 and the reducer 3 horizontally. On the other hand, connection via belt 7 allows the motor 4 and the reducer 3 to be separated horizontally without using multiple belts. This makes it possible to reduce the number of parts when laying out the motor 4. Reducing the number of parts is effective in saving space around the rotating section 2.

[0074] In the articulated robot 1 according to this embodiment, the robot arm 10 rotates around a first joint axis Ax1 parallel to the first axis O1 and the second axis O2. As illustrated in Fig. 1, the second axis O2 is closer to the first axis O1 than the first joint axis Ax1 is to the horizontal direction.

[0075] The second axis O2 can be spaced apart from the first joint axis Ax1 by the amount of the second axis O2 being brought closer to the first axis O1. The space between the second axis O2 and the first joint axis Ax1 is effective in suppressing interference between the motor 4 and the second base 11, and between the motor 4 and the actuator 13.

[0076] Moreover, the robot arm 10 according to this embodiment is a seven-axis vertical articulated robot arm, as illustrated in FIG.

[0077] Generally, a seven-axis robot arm has a high degree of freedom in its posture. Also, as described above, the entire articulated robot 1 can be considered as an eight-axis robot that rotates the rotating unit 2. An eight-axis robot has an even higher degree of freedom in its posture. Because of this high degree of freedom in its posture, the articulated robot 1 is suitable for loading and unloading goods.

[0078] (Modification) Fig. 3 is a diagram of a modified articulated robot 1 corresponding to Fig. 1. In the modified example shown in Fig. 3, the layout of the reducer 3 and the motor 4 relative to the rotating part 2 differs from that of the above embodiment.

[0079] 3, the reducer 3 according to the modified example is located above the support surface 26 along the first axis O1. The case 42 of the motor 4 is located above the support surface 26, similar to the reducer 3. The case 42 protrudes upward from the support surface 26.

[0080] In the modified example, the case 42 is located on the upper side with respect to the support surface 26, that is, above the support surface 26. In other words, the case 42 according to the modified example is located on the same side as the reducer 3 in the up-down direction with respect to the support surface 26. Moreover, as shown in Fig. 3, the second axis O2 of the motor 4 is offset in the horizontal direction with respect to the first axis O1, similar to the above embodiment.

[0081] Therefore, as in the above embodiment, the space created to the side of the reduction gear 3 is utilized without waste by arranging the motor 4. Utilization of the space makes the area around the revolving unit 2 more compact in the vertical direction. By making the area more compact in the vertical direction, the area around the revolving unit 2 can be made more space-saving.

[0082] In addition, by disposing the reduction gear 3 at the top, the first base 5 becomes compact in the vertical direction. By making the first base 5 compact, the space around the swivel unit 2 can be further saved.

[0083] (Other embodiments) In the above embodiment, the case 42 is inserted into the through hole 23a of the arm body 23, but the through hole 23a is not essential. For example, the case 42 may be attached to the lower surface of the first cover 24 or the second cover 25.

[0084] In addition, in the above embodiment, the reduction gear 3 and the motor 4 are connected by the belt 7, but the belt 7 is not essential. For example, the reduction gear 3 and the motor 4 may be connected by gears.

[0085] Moreover, it is not essential that the second axis O2 be closer to the first end 21 than to the second end 22 in the horizontal direction, as in the above embodiment. For example, the second axis O2 may be closer to the second end 22 than to the first end 21.

[0086] In the above embodiment, the robot arm 10 is a seven-axis vertical articulated robot arm, but it is not essential to adopt seven axes. The robot arm 10 may have six or fewer joints.

[0087] Whichever of the variations described above is adopted, it is possible to save space around the swivel unit 2. The same applies when a combination of the variations is adopted.

[0088] The above-mentioned arrangement can be applied not only to the arrangement of the reducer 3 and the motor 4 relative to the rotating part 2 but also to the arrangement of the reducer 3 and the actuator 13 relative to the second base 11 of the articulated robot 1.

[0089] [Aspects] The above-described embodiments are specific examples of the following aspects.

[0090] (Aspect 1) a reduction gear 3 located above or below the support surface 26 along a first axis Ax1 extending in the vertical direction and rotating the rotating unit 2 about the first axis Ax1; a shaft 41 rotating about a second axis O2 horizontally shifted from the first axis O1 and connected to the reduction gear 3; and a motor 4 having a case 42 that houses the shaft 41 and is supported by the rotating unit 2, the case 42 being located on the same side as the reduction gear 3 in the vertical direction with respect to the support surface 26.

[0091] (Aspect 2) The articulated robot 1 according to aspect 1, wherein the reducer 3 and the case 42 are located below the support surface 26.

[0092] (Aspect 3) The articulated robot 1 according to aspect 1 or aspect 2, wherein the rotating part 2 has a through hole 23a extending in the vertical direction and through which the case 42 passes.

[0093] (Aspect 4) The articulated robot (1) according to any one of aspects (1) to (3), further comprising a belt (7) connecting the shaft (41) to the reducer (3).

[0094] (Aspect 5) The articulated robot 1 according to any one of aspects 1 to 4, wherein the rotating section 2 has a first end 21 at which the reducer 3 is located along the first axis O1 and a second end 22 that supports the robot arm 10, the robot arm 10 rotates around a first joint axis Ax1 parallel to the first axis O1 and the second axis O2, and the second axis O2 is closer to the first end 21 than the second end 22 in the horizontal direction.

[0095] (Aspect 6) The articulated robot 1 according to any one of aspects 1 to 5, wherein the robot arm 10 is a seven-axis, vertical articulated robot arm. [Explanation of symbols]

[0096] 1 Articulated robot 10 Robot Arm 11 Second Base 13 Actuator 2 Swivel section 21 1st end 22 2nd end 23 Arm body 23a Through hole 24 1st Cover 25 2nd Cover 25a opening 26 Support surface 3 Reducer 33 No. 1 pulley 4 Motor 41 Shaft 41a 1st end 41b 2nd pulley 42 cases 5. First Base 7 Belt 8 Cable Ax1 First joint axis JT1 joint JT2 joint JT3 joint JT4 Joint JT5 Joint JT6 Joint JT7 Joint JT8 Joint O1 1st axis O2 2nd axis S1 First Storage Space S2 Second Storage Space

Claims

1. A robot arm having multiple joints; A rotating part having a support surface for supporting the robot arm; A reducer that is located above or below the support surface along a first axis that extends in a vertical direction and rotates the rotating part about the first axis; an articulated robot comprising: a shaft that rotates about a second axis that is horizontally offset from the first axis and is connected to the reducer; and a case that houses the shaft and is supported on the rotating section, the case being positioned on the same side as the reducer in the up-down direction with respect to the support surface.

2. The articulated robot according to claim 1, The articulated robot, wherein the reducer and the case are located below the support surface.

3. The articulated robot according to claim 2, The rotating part of the articulated robot extends in the vertical direction and has a through hole through which the case passes.

4. The articulated robot according to claim 1, A multi-joint robot comprising a belt connecting the shaft to the reducer.

5. The articulated robot according to claim 1, The swivel unit includes: a first end at which the reducer is located along the first axis; a second end supporting the robot arm; the robot arm rotates about a first joint axis parallel to the first axis and the second axis, The second axis is closer to the first end than to the second end in the horizontal direction.

6. The articulated robot according to any one of claims 1 to 5, The robot arm is a seven-axis, vertically articulated robot arm, i.e., an articulated robot.

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