robot

Abstract

A robot exhibits excellent assemblability and maintainability. The robot has a robotic arm comprising: a first arm; and a second arm connected to the first arm and rotating relative to the first arm about a first rotation axis. The first arm has: an axis along the first rotation axis; and a mounting portion disposed on the axis and detachably connected to the second arm. The second arm has a slit-shaped shaft through-hole, into which the shaft is radially inserted, and the slit-shaped shaft through-hole positions the shaft relative to the second arm. In the positional state by the shaft through-hole, the shaft is connected to the second arm via the mounting portion and rotates relative to at least one of the first and second arms.

Description

Technical Field

[0001] This invention relates to robots. Background Technology

[0002] The robot described in Patent Document 1 is a so-called "parallel linkage robot" and has: a base; a first arm that rotates relative to the base about a first rotation axis; a second arm that rotates relative to the first arm about a second rotation axis parallel to the first rotation axis; a first drive source for rotating the first arm; a second drive source for rotating the second arm; and a linkage mechanism that starts from the base end side of the first arm, connects to the end side of the first arm via multiple links, and transmits the rotational force generated by the second drive source to the second arm.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-073777

[0004] However, in such robots, no consideration was given to the ease of assembly and disassembly of the second arm relative to the first arm. Therefore, problems arise with low assemblability and maintainability. Summary of the Invention

[0005] The robot involved in the application examples of this invention has: A robotic arm has: a first arm; and a second arm connected to the first arm and rotating relative to the first arm about a first rotation axis. The first arm has: a shaft along a first rotation axis; and a mounting portion disposed on the shaft and detachably connected to the second arm. The second arm has a slit-shaped shaft through hole into which the shaft is inserted radially, and the slit-shaped shaft through hole positions the shaft relative to the second arm. The shaft, after being positioned through the shaft through the hole, is connected to the second arm via the mounting portion and rotates relative to at least one of the first arm and the second arm. Attached Figure Description

[0006] Figure 1 This is a perspective view showing the robot system according to the first embodiment.

[0007] Figure 2 This is a sectional view of the first arm.

[0008] Figure 3 This is a cross-sectional view of the base end of the third arm.

[0009] Figure 4 This is a three-dimensional view of the arm base of the third arm.

[0010] Figure 5This is a cross-sectional view of the end of the third arm.

[0011] Figure 6 This is a cross-sectional view showing the steps of mounting the third arm onto the second arm.

[0012] Figure 7 This is a cross-sectional view showing the steps of mounting the third arm onto the second arm.

[0013] Figure 8 This is the front view of the fourth arm.

[0014] Figure 9 This is a front view showing the steps of installing the fourth arm onto the third arm.

[0015] Figure 10 This is a front view showing the steps of installing the fourth arm onto the third arm.

[0016] Figure 11 This is a partial sectional view showing the fourth arm.

[0017] Figure 12 This is a sectional view of the end shaft of the fourth arm.

[0018] Figure 13 This is a partial cross-sectional view showing the intermediate rotary transmission component configured in the fourth arm.

[0019] Figure 14 It is a top view showing the configuration of the motor's rotating shaft, the rotating shaft of the intermediate rotation transmission component, and the rotating shaft of the end shaft.

[0020] Figure 15 This is a partial cross-sectional view showing the first drive unit.

[0021] Figure 16 This is a side view showing the linkage mechanism.

[0022] Figure 17 This is a partial cross-sectional view of the fourth arm of the robot according to the second embodiment.

[0023] Figure 18 This is a side view showing the steps of mounting the fourth arm onto the third arm.

[0024] Figure 19 This is a side view showing the steps of mounting the fourth arm onto the third arm.

[0025] Figure 20 This is a side view showing a modified example of a shaft passing through a hole.

[0026] Figure 21 This is a side view showing a modified example of a shaft passing through a hole.

[0027] Figure 22This is a side view showing a modified example of a shaft passing through a hole.

[0028] Explanation of reference numerals in the attached figures

[0029] 1: Robot system; 10: Robot; 110: Base; 120: Robotic arm; 121: First arm; 122: Second arm; 123: Third arm; 124: Fourth arm; 125: End shaft; 125a: Through hole; 131: Linkage mechanism; 131a: Link; 131b: Link; 131c: Pivot; 131d: Pivot; 132: Linkage mechanism; 132a: Link; 132b: Link; 132c: Link; 132d: Pivot; 132e: Pivot; 132f: Pivot; 132g: Pivot; 140: First drive unit; 141: Motor; 141a: Output shaft; 142: Power transmission unit; 142a: Input-side rotational transmission component; 142b: Output-side rotational transmission component. 142c: Ring-shaped component; 150: Second drive unit; 151: Motor; 151a: Output shaft; 152: Power transmission part; 152a: Input-side rotational transmission component; 152b: Output-side rotational transmission component; 152c: Ring-shaped component; 160: Third drive unit; 161: Motor; 161a: Output shaft; 162: Power transmission part; 162a: Input-side rotational transmission component; 162b: Output-side rotational transmission component; 162c: Ring-shaped component; 163: Bearing part; 20: Arm base; 21: Shaft; 22: Bearing part; 23: Bearing part; 30: Arm base; 31: Shaft; 32: First connecting part; 321: First bearing part; 322: First bearing holding part; 3 3: Second connecting part; 331: Second bearing part; 332: Second bearing retaining part; 34: Third connecting part; 341: Third bearing part; 342: Third bearing retaining part; 35: Restricting part; 351: Flange; 352: Gasket; 353: Gasket; 354: Gasket; 355: Gasket; 356: Nut; 357: Nut; 40: Arm base; 40a: First base plate; 40b: Second base plate; 41: Bottom; 42: Side plate part; 421: Shaft through hole; 422: Shaft through hole; 43: Side plate part; 431: Shaft through hole; 432: Shaft through hole; 50: Arm base; 50a: First base plate; 50b: Second base plate; 500: Restricting part; 501: Flange; 5 02: Flange; 503: Shim; 504: Shim; 505: Shim; 506: Shim; 507: Shim; 508: Nut; 509: Nut; 51: Bottom; 52: Side plate; 521: Shaft through hole; 53: Side plate; 531: Shaft through hole; 54: Shaft; 55: Shaft retaining part; 551: Bearing part; 552: Bearing retaining part; 56: Shaft retaining part; 561: Bearing part; 562: Bearing retaining part; 57: Mounting part; 58: Mounting part; 59: Connecting part; 60: Drive unit; 61: Motor; 611: Output shaft; 62: Power transmission part; 621: Input side rotation transmission component; 622: Output side rotation transmission component; 623: Intermediate rotation transmission component;623a: Third rotational transmission component; 623b: Fourth rotational transmission component; 624: First annular component; 625: Second annular component; 68: Holding part; 681: Bearing part; 682: Bearing holding part; 69: Support part; 90: Control device; A1: Rotating shaft; A2: Rotating shaft; A3: Rotating shaft; A4: Rotating shaft; A5: Rotating shaft; B1: Rotating shaft; B2: Rotating shaft; J1: Shaft; J2: Shaft; J3: Shaft; J4: Shaft; J5: Shaft; J6: Shaft; LL: Virtual straight line; Q1: Parallelogram; Q11: Straight line; Q12: Straight line; Q2: Parallelogram; Q21: Straight line; Q22: Straight line; Q3: Parallelogram; Q31: Straight line; Q32: Straight line; V: Radial. Detailed Implementation

[0030] The robot of the present invention will now be described in detail based on the embodiments shown in the accompanying drawings. In the figures, for ease of explanation, three mutually orthogonal axes are illustrated: the X-axis, Y-axis, and Z-axis. The Z-axis is vertical, while the X-axis and Y-axis are horizontal. Furthermore, in the following text, the direction along the X-axis will be referred to as the X-axis direction, the direction along the Y-axis as the Y-axis direction, and the direction along the Z-axis as the Z-axis direction. Additionally, the side with the arrow on the Z-axis will be referred to as the upper side, and the opposite side as the lower side.

[0031] Furthermore, in this specification, the terms "orthogonal," "parallel," and "symmetrical" refer to their meanings within the permissible range of manufacturing tolerances. Specifically, "orthogonal" means substantially orthogonal, including angles between two lines or planes ranging from 80 degrees to 100 degrees. "Parallel" means substantially parallel, including angles between two lines or planes ranging from 0 degrees to 10 degrees. "Symmetrical" means substantially symmetrical, including when one element is superimposed on the other, the ratio of the overlapping area to the total area of ​​the two elements is between 90% and 100%.

[0032] First Implementation Method

[0033] Figure 1 This is a perspective view showing the robot system according to the first embodiment. Figure 2 This is a sectional view of the first arm. Figure 3 This is a cross-sectional view of the base end of the third arm. Figure 4 This is a three-dimensional view of the arm base of the third arm. Figure 5 This is a cross-sectional view of the end of the third arm. Figure 6 and Figure 7 This is a cross-sectional view showing the steps of mounting the third arm onto the second arm. Figure 8 This is the front view showing the fourth arm. Figure 9 and Figure 10This is a front view showing the steps of installing the fourth arm onto the third arm. Figure 11 This is a partial sectional view showing the fourth arm. Figure 12 This is a sectional view of the end shaft of the fourth arm. Figure 13 This is a partial cross-sectional view showing the intermediate rotary transmission component configured in the fourth arm. Figure 14 It is a top view showing the configuration of the motor's rotating shaft, the rotating shaft of the intermediate rotation transmission component, and the rotating shaft of the end shaft. Figure 15 This is a partial cross-sectional view showing the first drive unit. Figure 16 This is a side view showing the linkage mechanism.

[0034] Figure 1 The robot system 1 shown includes a robot 10 and a control device 90 that controls the operation of each part of the robot 10.

[0035] Control device 90

[0036] The control device 90 is connected to the robot 10 via wired or wireless means, capable of transmitting and receiving signals, and controls the operation of various parts of the robot 10. The control device 90 is, for example, a computer, and includes a processor such as a CPU (Central Processing Unit), a storage unit consisting of volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory), and a communication unit for transmitting and receiving signals with the robot. Furthermore, various programs executable by the processor are stored in the storage unit. The processor controls the operation of various parts of the robot 10 by reading and executing the programs stored in the storage unit. It should be noted that in this embodiment, the control device 90 is disposed on the outside of the robot 10, but the placement of the control device 90 is not particularly limited; for example, it may also be disposed inside the robot 10.

[0037] Robot 10

[0038] Robot 10 is a parallel-link, multi-joint robot, used for food manufacturing in a broad sense, including food conveying, food serving, food packaging, and food processing. In this case, the workpiece in robot 10 is food or food packaging. However, the application of robot 10 and the type of workpiece are not particularly limited.

[0039] The robot 10 has a base 110 fixed to the floor or the like and a robotic arm 120 rotatably connected to the base 110. The robotic arm 120 is configured to be rotatably connected from the base 110 side by a first arm 121, a second arm 122, a third arm 123 and a fourth arm 124 in that order.

[0040] Specifically, the robotic arm 120 includes: a first arm 121 rotatably connected to a base 110 about a rotation axis A1 along the Z-axis; a second arm 122 rotatably connected to the first arm 121 about a rotation axis A2 along the X-axis; a third arm 123 rotatably connected to the second arm 122 about a rotation axis A3 along the X-axis; and a fourth arm 124 rotatably connected to the third arm 123 about a rotation axis A4 along the X-axis. An end effector 125 rotatable about a rotation axis A5 along the Z-axis is disposed on the fourth arm 124. Furthermore, an end effector (not shown) for performing a predetermined operation on the workpiece is detachably mounted to the end effector 125. It should be noted that the end effector may or may not be a component of the robot 10.

[0041] Thus, by utilizing four arms 121, 122, 123, and 124 to construct the robotic arm 120, the number of arms can be reduced, thereby decreasing the manufacturing cost of the robot 10. Therefore, the robot 10 can be provided at a low cost. Next, each arm 121 to 124 will be described sequentially. It should be noted that in this embodiment, the fourth arm 124 is the "first arm" of the present invention, and the third arm 123 is the "second arm" of the present invention. Furthermore, the rotation axis A4 is the "first rotation axis" of the present invention.

[0042] First arm 121

[0043] First, the first arm 121 will be described. The first arm 121 is located on the upper side of the base 110 and is capable of rotating relative to the base 110 about the rotation axis A1. For example... Figure 2 As shown, this first arm 121 has an arm base 20. Furthermore, at the upper end of the arm base 20, a shaft 21 extending along the X-axis is held rotatably by bearing portions 22 and 23. In the robot 10, a rotation axis A2 is formed by this shaft 21.

[0044] Second arm 122

[0045] Next, the second arm 122 will be described. For example... Figure 1 As shown, the second arm 122 is located at the end of the first arm 121 and is rotatable relative to the first arm 121 about the rotation axis A2. Furthermore, the second arm 122 has a rod-shaped arm base 30 extending in a direction orthogonal to the rotation axis A2. And, as... Figure 2 As shown, the base end of the arm base 30 is fixed to the shaft 21. Therefore, the arm base 30 rotates together with the shaft 21 about the rotation axis A2. In particular, the arm base 30 is fixed to the central part of the shaft 21, that is, the part located between the bearing portions 22 and 23. With this configuration, since the arm base 30 is supported from both sides, the rotation of the arm base 30 is stable. In addition, as... Figure 3As shown, a shaft 31 extending along the X-axis is fixed to the end of the arm base 30. In the robot 10, the rotation axis A3 is formed by this shaft 31. Furthermore, the arm base 30 supports the shaft 31 at its central portion, that is, the portion excluding the two ends. Therefore, the two ends of the shaft 31 protrude from the arm base 30 to both sides in the X-axis direction.

[0046] And, as Figure 3 As shown, the second arm 122 has a first connecting portion 32 and a second connecting portion 33 disposed at both ends of the shaft 31. The first connecting portion 32 is located on the positive side of the arm base 30 in the X-axis direction, and the second connecting portion 33 is located on the negative side of the arm base 30 in the X-axis direction. That is, the first and second connecting portions 32 and 33 are located on opposite sides of each other in the X-axis direction relative to the arm base 30. Furthermore, the third arm 123 can be rotatably connected to the arm base 30 about the rotation axis A3 via these first and second connecting portions 32 and 33.

[0047] Furthermore, the second arm 122 has a third connecting portion 34 disposed on the shaft 31 between the arm base 30 and the second connecting portion 33. The connecting rod 132b is rotatably connected to the shaft 31 via the third connecting portion 34. It should be noted that the connecting rod 132b will be described in detail in the section on the linkage mechanism 132 described later.

[0048] The first connecting portion 32 has a first bearing portion 321 through which the shaft 31 passes and a first bearing retaining portion 322 for retaining the first bearing portion 321. The first bearing retaining portion 322 is rotatable relative to the shaft 31 about the rotation axis A3. Furthermore, the first bearing retaining portion 322 is connected to the third arm 123. The first bearing portion 321 is a deep groove ball bearing and has an inner ring for fixing the shaft 31, an outer ring for fixing the first bearing retaining portion 322, and a plurality of balls sandwiched between them.

[0049] Similarly, the second connecting portion 33 has a second bearing portion 331 through which the shaft 31 passes and a second bearing retaining portion 332 for retaining the second bearing portion 331. The second bearing retaining portion 332 is rotatable relative to the shaft 31 about the rotation axis A3. Furthermore, the second bearing retaining portion 332 is connected to the third arm 123. The second bearing portion 331 is a deep groove ball bearing and has an inner ring for fixing the shaft 31, an outer ring for fixing the second bearing retaining portion 332, and a plurality of balls sandwiched between them.

[0050] Similarly, the third connecting portion 34 has a third bearing portion 341 through which the shaft 31 passes and a third bearing retaining portion 342 for retaining the third bearing portion 341. The third bearing retaining portion 342 is rotatable relative to the shaft 31 about the rotation axis A3. Furthermore, the connecting rod 132b is fixed to the third bearing retaining portion 342. The third bearing portion 341 is composed of two deep groove ball bearings arranged side by side. Each deep groove ball bearing has an inner ring for fixing the shaft 31, an outer ring for fixing the third bearing retaining portion 342, and a plurality of balls sandwiched between them.

[0051] It should be noted that in industrial robots like Robot 10, crossed roller bearings, which can achieve high rigidity and rotational accuracy, are often used. However, crossed roller bearings are prone to large-scale construction and are also expensive. In contrast, by using deep groove ball bearings, which are widely used as "rolling bearings," as the first, second, and third bearing sections 321, 331, and 341, the manufacturing cost of Robot 10 can be effectively reduced, allowing Robot 10 to be provided at a lower cost. Furthermore, due to the simple and small structure of deep groove ball bearings, the miniaturization and weight reduction of Robot 10 can also be achieved.

[0052] However, the configuration of the first and second connecting parts 32 and 33 is not particularly limited as long as it allows the third arm 123 to be rotatably connected to the shaft 31 around the rotation axis A3. Similarly, the configuration of the third connecting part 34 is not particularly limited as long as it allows the connecting rod 132b to be rotatably connected to the shaft 31 around the rotation axis A3. For example, the first, second, and third bearing parts 321, 331, and 341 can also be cylindrical roller bearings, angular contact ball bearings, etc.

[0053] In addition, such as Figure 3 As shown, the second arm 122 has a limiting part 35 that restricts the third arm 123 from deviating from the second arm 122 in the direction along the rotation axis A3. By having the limiting part 35, the decrease in positional accuracy due to deviation can be suppressed. In addition, the torsion of each part can be effectively suppressed, and the drive of the robot 10 is stable in the long term. It should be noted that the limiting part 35 is not particularly limited, but in this embodiment, it has a flange 351 protruding from the shaft 31, four annular gaskets 352, 353, 354, and 355 mounted on the shaft 31, and nuts 356 and 357 mounted on both ends of the shaft 31, which together form a configuration that restricts the deviation of the first, second, and third connecting parts 32, 33, and 34.

[0054] Specifically, flange 351 is located between the first connecting portion 32 and arm base 30, and gasket 352 is located on the outside of the first connecting portion 32, that is, on the positive side in the X-axis direction. Furthermore, nut 356 is fastened to shaft 31 on the outside of the first connecting portion 32. Therefore, by tightening nut 356, the first connecting portion 32 is clamped between flange 351 and gasket 352, and the position of the first connecting portion 32 is fixed.

[0055] Furthermore, gasket 353 is located between the arm base 30 and the third connecting portion 34, gasket 354 is located between the third connecting portion 34 and the second connecting portion 33, and gasket 355 is located on the outside of the second connecting portion 33, that is, on the negative side in the X-axis direction. Nut 357 is fastened to the shaft 31 on the outside of the second connecting portion 33. Therefore, by tightening nut 357, the third connecting portion 34 is clamped between gaskets 353 and 354, and the position of the third connecting portion 34 is fixed. Additionally, the second connecting portion 33 is clamped between gaskets 354 and 355, and the position of the second connecting portion 33 is fixed.

[0056] In particular, as in this embodiment, by having a flange 351 integrally formed with the shaft 31 and not deviating relative to the shaft 31, the first, second, and third connecting portions 32, 33, and 34 can be positioned using the flange 351 as a reference. Therefore, the positioning accuracy of the first, second, and third connecting portions 32, 33, and 34 is improved.

[0057] Third arm 123

[0058] Next, the third arm 123 will be described. As mentioned above, in this embodiment, the third arm 123 constitutes the "second arm" of the present invention. Figure 1 As shown, the third arm 123 is located at the end of the second arm 122 and is rotatable relative to the second arm 122 about the rotation axis A3. Furthermore, the third arm 123 has an arm base 40 extending in a direction orthogonal to the rotation axis A2. Figure 4 As shown, the arm base 40 is a component formed by bending a metal plate such as steel plate, and is a U-shaped semi-tubular structure. Specifically, the arm base 40 has: a plate-shaped bottom 41; and a pair of side plates 42, 43, which are erected vertically from the ends of the bottom 41 in the X-axis direction. The side plates 42, 43 are arranged side by side in the X-axis direction, with side plate 42 located on the positive side of the arm base 30 in the X-axis direction and side plate 43 located on the negative side of the X-axis direction. In addition, side plate 42 extends further towards the base end than side plate 43, such as... Figure 1 As shown, the end portion of link 131b is rotatably connected to its base end. Link 131b will be described in the link mechanism 131 described later.

[0059] In particular, in this embodiment, such as Figure 4 and Figure 5 As shown, the arm base 40 is constructed by integrally fastening two parts—an L-shaped first base piece 40a having a bottom 41 and a side plate portion 42, and an L-shaped second base piece 40b having a bottom 41 and a side plate portion 43—with screws. Specifically, the bottom 41 of both the first and second base pieces 40a and 40b are overlapped, and this part is fastened to each other with screws, thereby forming an arm base 40 integrally connected by the first and second base pieces 40a and 40b. Therefore, by removing the screws, the arm base 40 can be easily separated into the first base piece 40a and the second base piece 40b. Therefore, as will be described later, the assembly and disassembly of the third arm 123 relative to the arm base 30 becomes easier, and the assemblability and maintainability of the robot 10 are improved. In particular, by using screws to connect the first and second base pieces 40a and 40b, the first and second base pieces 40a and 40b can be easily connected or separated. However, there are no particular limitations on the method of detachably connecting the first and second base plates 40a and 40b.

[0060] In addition, such as Figure 4 and Figure 5 As shown, shaft through holes 421 and 431, arranged side-by-side in the X-axis direction, are formed at the base ends of a pair of side plate portions 42 and 43. The shaft through holes 421 and 431 are closed holes. Furthermore, as... Figure 3 As shown, both ends of the shaft 31 pass through shaft through holes 421 and 431. That is, the first base plate 40a is inserted into the positive X-axis end of the shaft 31 from the outside of the first connecting portion 32, i.e., the positive X-axis side, and the second base plate 40b is inserted into the negative X-axis end of the shaft 31 from the outside of the second connecting portion 33, i.e., the negative X-axis side. Furthermore, around the shaft through hole 421, the side plate portion 42 and the first bearing retaining portion 322 of the first connecting portion 32 are fixed by multiple screws in a screw-locking manner; around the shaft through hole 431, the side plate portion 43 and the second bearing retaining portion 332 of the second connecting portion 33 are fixed by multiple screws in a screw-locking manner. Thus, the third arm 123 is connected to the shaft 31 in a manner that allows it to rotate around the rotation axis A3.

[0061] Here, the side plate portion 42 is located on the outer side relative to the first connecting portion 32, that is, on the positive side in the X-axis direction. Therefore, the first base plate 40a can be removed from the shaft 31 simply by removing the screws fixing the side plate portion 42 and the first bearing retaining portion 322. Furthermore, since the screws fixing the side plate portion 42 and the first bearing retaining portion 322 are tightened from the side plate portion 42 side, the screw heads are exposed on the outer side, making disassembly and assembly easy. Similarly, the side plate portion 43 is located on the outer side relative to the second connecting portion 33, that is, on the negative side in the X-axis direction. Therefore, the second base plate 40b can be removed from the shaft 31 simply by removing the screws fixing the side plate portion 43 and the second bearing retaining portion 332. Furthermore, since the screws fixing the side plate portion 43 and the second bearing retaining portion 332 are tightened from the side plate portion 43 side, the screw heads are exposed on the outer side, making disassembly and assembly easy. With this configuration, the disassembly and assembly of the third arm 123 relative to the second arm 122 becomes easier, and the assemblability and maintainability of the robot 10 are improved.

[0062] For example, when assembling the third arm 123 onto the second arm 122, firstly, with the first and second base pieces 40a and 40b separated, as follows: Figure 6 As shown, one end of the shaft 31 passes through the shaft through hole 421 of the side plate portion 42, and the side plate portion 42 and the first bearing retaining portion 322 are screwed together. Thus, the first base plate 40a is mounted onto the shaft 31. Next, as... Figure 7 As shown, the other end of the shaft 31 passes through the shaft through hole 431 of the side plate portion 43 to screw fasten the side plate portion 43 and the second bearing retaining portion 332. Thus, the second base plate 40b is mounted onto the shaft 31. Next, the bottoms 41 of the first and second base plates 40a and 40b are overlapped and screwed fastened together, forming an integrated unit. As described above, the third arm 123 is assembled onto the second arm 122. It should be noted that when removing the third arm 123 from the second arm 122, the reverse steps are performed. In this way, the third arm 123 can be disassembled and assembled from the second arm 122 by only removing and installing the screws on the arm base 40. Therefore, the assemblability and maintainability of the robot 10 are improved.

[0063] In addition, such as Figure 4 and Figure 8 As shown, slit-shaped shaft through holes 422 and 432, arranged side-by-side in the X-axis direction, are formed at the ends of a pair of side plate portions 42 and 43. The shaft 54, described later, of the fourth arm 124 passes through these shaft through holes 422 and 432. It should be noted that the shaft through holes 422 and 432 are elongated holes opening onto the outer edges of the side plate portions 42 and 43, respectively. Furthermore, the shaft through holes 422 and 432 extend in directions orthogonal to the extension direction of the third arm 123 and the X-axis direction, respectively, and their lower ends in the figure open onto the outer edges of the side plate portions 42 and 43.

[0064] Fourth arm 124

[0065] Next, the fourth arm 124 will be described. As mentioned earlier, in this embodiment, the fourth arm 124 constitutes the "first arm" of the present invention. Figure 1 As shown, the fourth arm 124 is located at the end of the third arm 123 and is capable of rotating relative to the third arm 123 about a rotation axis A4, which serves as the first rotation axis. Additionally, as... Figure 8 As shown, the fourth arm 124 has an arm base 50 extending in a direction orthogonal to the rotation axis A4. The arm base 50 is a component formed by bending a metal plate such as steel plate and is U-shaped. Furthermore, the arm base 50 has: a plate-shaped bottom 51 along a horizontal plane, i.e., the XY plane; and a pair of side plates 52, 53 erected upwards from the ends of the bottom 51 in the X-axis direction. The side plates 52, 53 are arranged side-by-side in the X-axis direction, with side plate 52 located on the positive side of the side plate 53 in the X-axis direction. Additionally, as... Figure 1 As shown, the side plate portion 53 is slightly larger than the side plate portion 52, and its upper end is rotatably connected to the end portion of the connecting rod 132c. It should be noted that the connecting rod 132c will be described in the link mechanism 132 described later.

[0066] In particular, in this embodiment, the arm base 50 is constructed by screwing together two parts: a plate-shaped first base piece 50a having a side plate portion 52 and an L-shaped second base piece 50b having a bottom 51 and a side plate portion 53. Specifically, the first and second base pieces 50a and 50b are overlapped at the side plate portion 52, and the overlapping portions are fastened with screws, thereby forming an arm base 50 integrally formed by the first and second base pieces 50a and 50b. Therefore, by removing the screws, the arm base 50 can be easily separated into the first base piece 50a and the second base piece 50b. With this configuration, it becomes easier to assemble and disassemble the bottom 51, improving the assemblability and maintainability of the robot 10. However, the configuration of the arm base 50 is not particularly limited; for example, the bottom 51 and the side plate portions 52 and 53 may also be integrally formed from a single metal plate.

[0067] Furthermore, the fourth arm 124 has a connecting portion 59 that connects the side plate portions 52 and 53 to each other. The connecting portion 59 is a U-shaped plate component formed by bending a metal plate such as a steel plate, and its two ends are fixed to the side plate portions 52 and 53 by screws. In this way, the connecting portion 59 functions as a reinforcement portion for reinforcing the arm base 50 and as a support portion for supporting the drive unit 60 described later.

[0068] In addition, such as Figure 8As shown, shaft through holes 521 and 531 are formed side-by-side in the X-axis direction at the upper ends of side plate portions 52 and 53. It should be noted that shaft through holes 521 and 531 are elongated cutouts extending along the Y-axis direction with their negative Y-axis ends opening onto the outer edges of side plate portions 52 and 53. A shaft 54 ​​extending along the X-axis direction passes through these shaft through holes 521 and 531. The shaft 54 ​​is rotatably held in the side plate portions 52 and 53 via a pair of shaft holding portions 55 and 56. In the robot 10, a rotation axis A4 is formed by this shaft 54. However, the shaft through holes 521 and 531 are not particularly limited; for example, they can also be closed holes.

[0069] The shaft retaining portion 55 includes: a bearing portion 551 through which the shaft 54 ​​passes; and a bearing retaining portion 552 that retains the bearing portion 551, the bearing retaining portion 552 being rotatable relative to the shaft 54 ​​about a rotation axis A4. Furthermore, the shaft retaining portion 55 is fixed to the side plate portion 52 in the bearing retaining portion 552 by screws. The bearing portion 551 is a deep groove ball bearing and has an inner ring for fixing the shaft 54, an outer ring for fixing the bearing retaining portion 552, and a plurality of balls sandwiched between them.

[0070] Similarly, the shaft retaining portion 56 has: a bearing portion 561 through which the shaft 54 ​​passes; and a bearing retaining portion 562 that retains the bearing portion 561, and the bearing retaining portion 562 is rotatable relative to the shaft 54 ​​about the rotation axis A4. Furthermore, the shaft retaining portion 56 is fixed to the side plate portion 53 in the bearing retaining portion 562 by screws. The bearing portion 561 is a deep groove ball bearing and has an inner ring for fixing the shaft 54, an outer ring for fixing the bearing retaining portion 562, and a plurality of balls sandwiched between them.

[0071] In this way, by using deep groove ball bearings as bearing portions 551 and 561, the manufacturing cost of robot 10 can be effectively reduced, and robot 10 can be provided at a lower cost. Furthermore, since deep groove ball bearings have a simple and small structure, miniaturization and weight reduction of robot 10 can also be achieved. However, there are no particular limitations on the configuration of shaft retaining portions 55 and 56, as long as the shaft 54 ​​can be rotatably held in the side plate portions 52 and 53. For example, bearing portions 551 and 561 can also be cylindrical roller bearings, angular contact ball bearings, etc.

[0072] Furthermore, the shaft retaining part 55 is located inside the side plate part 52, that is, on the negative side in the X-axis direction, and the shaft retaining part 56 is located inside the side plate part 53, that is, on the positive side in the X-axis direction. In other words, the shaft retaining parts 55 and 56 are located between the side plate parts 52 and 53. Therefore, the shaft retaining parts 55 and 56 can be prevented from extending beyond the arm base 50, enabling miniaturization of the fourth arm 124. Additionally, the screws securing the side plate part 52 and the bearing retaining part 552 are tightened from the side plate part 52 side, with the screw heads protruding outside the arm base 50. Similarly, the screws securing the side plate part 53 and the bearing retaining part 562 are tightened from the side plate part 53 side, with the screw heads protruding outside the arm base 50. Therefore, the installation and removal of these screws are easy.

[0073] In addition, such as Figure 8 As shown, the fourth arm 124 has a pair of mounting portions 57 and 58 disposed on the shaft 54. One mounting portion 57 is located between the shaft holding portions 55 and 56, and the other mounting portion 58 is located outside the shaft holding portion 56, that is, on the negative side in the X-axis direction. That is, on the shaft 54, the shaft holding portion 55, the mounting portion 57, the shaft holding portion 56, and the mounting portion 58 are arranged side by side in sequence from the positive side in the X-axis direction, and the shaft holding portions 55 and 56 and the mounting portions 57 and 58 are arranged alternately. However, the arrangement of the shaft holding portions 55 and 56 and the mounting portions 57 and 58 is not particularly limited.

[0074] Mounting portions 57 and 58 are flanges of discs protruding radially from the outer periphery of shaft 54. Furthermore, mounting portions 57 and 58 are formed as separate entities from shaft 54 ​​and are fixed to shaft 54 ​​by means of screws or similar methods. Shaft 54 ​​is connected to the third arm 123 via these mounting portions 57 and 58 in a detachable manner. Specifically, around shaft 54, mounting portion 57 is fixed to side plate portion 42 by multiple screws; around shaft 54, mounting portion 58 is fixed to side plate portion 43 by multiple screws. By making mounting portions 57 and 58 flange-shaped, their configuration is simplified, and they are easily fixed to the third arm 123 around shaft 54. Furthermore, by fixing mounting portions 57 and 58 and the third arm 123 with screws, they can be easily installed and removed.

[0075] Thus, by forming the mounting portions 57 and 58 and the shaft 54 ​​as separate entities, their formation becomes easier. Furthermore, the freedom of shape and material for the shaft 54 ​​and the mounting portions 57 and 58 is increased. However, this is not a limitation; for example, at least one of the mounting portions 57 and 58 may be integrally formed with the shaft 54. Even by integrally forming at least one of the mounting portions 57 and 58 with the shaft 54, they can be easily formed. Additionally, since there is no need to fix at least one of the mounting portions 57 and 58 to the shaft 54, the assembly of the robot 10 becomes easier. Furthermore, since there is no deviation of at least one of the mounting portions 57 and 58 relative to the shaft 54, the drive of the robot 10 remains stable over a long period. It should be noted that, in this embodiment, in order to facilitate the operation of passing the shaft 54 ​​through the bearing portion 561, it is preferable that the mounting portion 58 is not integrally formed with the shaft 54, and only the mounting portion 57 is integrally formed with the shaft 54.

[0076] Here, the steps for attaching the fourth arm 124 to the third arm 123 are explained. First, as Figure 9 As shown, shaft 54, along the X-axis direction, is inserted radially (in a direction orthogonal to the X-axis) into a pair of shaft through holes 422, 432 formed at the end of the third arm 123. Then, as... Figure 10 As shown, the outer peripheral surface of shaft 54 ​​is brought into contact with the bottom of shaft through holes 422 and 432. This positions shaft 54 ​​relative to the third arm 123, allowing the rotating shaft A4 to be positioned correctly. Next, maintaining this state, mounting portions 57 and 58 and the arm base 40 are secured with screws. Specifically, mounting portion 57 and side plate portion 42 are secured with screws, and mounting portion 58 and side plate portion 43 are secured with screws. The fourth arm 124 is then attached to the third arm 123. It should be noted that when removing the fourth arm 124 from the third arm 123, the reverse steps are performed. Thus, the fourth arm 124 can be attached to the third arm 123 simply by removing and installing screws on the arm base 40. Therefore, the assemblability and maintainability of the robot 10 are improved. Furthermore, since only the fourth arm 124 can be removed, its maintainability is improved.

[0077] Here, as Figure 10As shown, the mounting portion 57 is located on the outer side relative to the side plate portion 42, that is, on the positive side in the X-axis direction. Furthermore, the screws securing the mounting portion 57 and the side plate portion 42 are tightened from the side plate portion 42 side. On the outer side of the side plate portion 42, that is, on the positive side in the X-axis direction, the shaft retaining portion 55 is located nearby, making it difficult to ensure sufficient space for screw tightening. In contrast, a wider space is ensured on the inner side of the side plate portion 42 than on the outer side. Therefore, as in this embodiment, by tightening the screws from the side plate portion 42 side, it is easy to ensure sufficient space for screw tightening, allowing the operation to be performed smoothly. On the other hand, the mounting portion 58 is located on the inner side relative to the side plate portion 43, that is, on the positive side in the X-axis direction. Furthermore, the screws securing the mounting portion 58 and the side plate portion 43 are tightened from the side plate portion 43 side. Therefore, the screw heads are exposed on the outer side, making screw removal and installation easier. With this configuration, the fourth arm 124 is easier to assemble and disassemble relative to the third arm 123, improving the assemblability and maintainability of the robot 10.

[0078] Furthermore, as mentioned above, since a mounting portion 57 is arranged between the shaft holding portions 55 and 56, the shaft 54 ​​is fixed to the side plate portion 42 via the mounting portion 57 at the portion between the shaft holding portions 55 and 56. With this configuration, since the central portion of the shaft 54 ​​is supported by the third arm 123, the shaft 54 ​​is less prone to bending. Therefore, the rotating shaft A4 is less likely to vibrate, and the rotation of the fourth arm 124 is stable.

[0079] In addition, such as Figure 8 As shown, the fourth arm 124 has a limiting portion 500 that restricts the deviation of the fourth arm 124 relative to the third arm 123 in the direction along the rotation axis A4. By having the limiting portion 500, the decrease in positional accuracy associated with the deviation can be suppressed. In addition, the torsion of each part can be effectively suppressed, and the drive of the robot 10 is stable in the long term. It should be noted that the limiting portion 500 is not particularly limited, but in this embodiment, it has two flanges 501, 502 protruding from the shaft 54, five annular gaskets 503, 504, 505, 506, 507 mounted on the shaft 54, and nuts 508, 509 mounted on both ends of the shaft 54, thereby forming a configuration that restricts the deviation of the shaft holding portions 55, 56 and the mounting portions 57, 58.

[0080] Specifically, flange 501 is located inside side plate portion 42, and gasket 505 is located between side plate portion 42 and flange 501. Additionally, gasket 504 is located between shaft retaining portion 55 and mounting portion 57, and gasket 503 is located outside shaft retaining portion 55. Furthermore, nut 508 is fastened to shaft 54 ​​from the outside of gasket 503. Therefore, by tightening nut 508, shaft retaining portion 55 and mounting portion 57 are clamped between flange 501 and gasket 503, and their positions are fixed.

[0081] Furthermore, the flange 502 is located inside the shaft retaining portion 56, and the gasket 506 is located between the shaft retaining portion 56 and the mounting portion 58. Additionally, the gasket 507 is located outside the side plate portion 43, and the nut 509 is fastened to the shaft 54 ​​from the outside of the gasket 507. Therefore, by tightening the nut 509, the shaft retaining portion 56 and the mounting portion 58 are clamped between the flange 502 and the gasket 507, and their positions are fixed.

[0082] In particular, as in this embodiment, by having flanges 501 and 502 integrally formed with the shaft 54 ​​and not deviating relative to the shaft 54, the shaft holding portion 55 and the mounting portion 57 can be positioned with the flange 501 as a reference, and the shaft holding portion 56 and the mounting portion 58 can be positioned with the flange 502 as a reference. Therefore, the positioning accuracy of the shaft holding portions 55 and 56 and the mounting portions 57 and 58 is improved.

[0083] It should be noted that, as Figure 9 and Figure 10 As shown, when attaching the fourth arm 124 to the third arm 123, it is sufficient to remove the gaskets 503, 507 and nuts 508, 509 located at both ends of the shaft 54 ​​beforehand, attach the fourth arm 124 to the third arm 123, and then install the gaskets 503, 507 and nuts 508, 509 onto the shaft 54. Alternatively, the gaskets 503, 507 and nuts 508, 509 may not be removed from the shaft 54, but the nuts 508, 509 may be fully loosened.

[0084] In addition, such as Figure 11 As shown, the fourth arm 124 has the aforementioned end shaft portion 125 and a drive unit 60 for rotating the end shaft portion 125 about the rotation axis A5. In addition, the drive unit 60 includes: a motor 61 having an output shaft 611; and a power transmission unit 62 for transmitting the rotation of the output shaft 611 to the end shaft portion 125.

[0085] The end shaft 125 is held at the bottom 51 in a manner that allows it to rotate about a rotation axis A5 along the Z-axis. The rotation axis A5 is parallel to the rotation axis A1 of the first arm 121 and is parallel to but separated from the rotation axis A1 in the Y-axis direction. That is, the rotation axes A1 and A5 are far apart from each other, and the line segment connecting the rotation axes A1 and A5 is parallel to the Y-axis. Furthermore, as... Figure 12 As shown, the end shaft portion 125 is hollow and has through holes 125a extending through both end faces, namely the upper and lower surfaces. With this configuration, for example, wiring or conduits connected to the end effector can be laid within the through holes 125a. Therefore, it is possible to prevent wiring or conduits from protruding around the end effector, and the wiring or conduits are less likely to become obstacles to operation.

[0086] The motor 61 is, for example, a servo motor, particularly a three-phase motor driven by three-phase AC, and is fixed to the connecting part 59 via the support part 69. Furthermore, the output shaft 611 of the motor 61 rotates about a rotation axis B1 along the Z-axis. It should be noted that the rotation axis B1 is parallel to and separate from the rotation axis A1.

[0087] The power transmission unit 62 is a speed reducer and has an input-side rotary transmission member 621 as a first rotary transmission member, an output-side rotary transmission member 622 as a second rotary transmission member, an intermediate rotary transmission member 623, a first annular member 624 wrapped around the input-side rotary transmission member 621 and the intermediate rotary transmission member 623, and a second annular member 625 wrapped around the intermediate rotary transmission member 623 and the output-side rotary transmission member 622.

[0088] The input-side rotational transmission member 621 is disposed and fixed to the output shaft 611, and rotates together with the output shaft 611 about the rotational axis B1. On the other hand, the output-side rotational transmission member 622 is disposed and fixed to the end shaft portion 125, and rotates together with the end shaft portion 125 about the rotational axis A5. The intermediate rotational transmission member 623 is held at the bottom 51 by the holding portion 68 in a manner that allows it to rotate about the rotational axis B2 along the Z-axis. It should be noted that the rotational axis B2 is parallel to the rotational axis A1 and is separated from the rotational axes A1 and B1. That is, the rotational axes A5, B1, and B2 are parallel to each other and separated from each other.

[0089] like Figure 13 As shown, the retaining part 68 has a bearing part 681 and a bearing retaining part 682 that retains the bearing part 681. The retaining part 68 is fixed to the bottom 51 in the bearing retaining part 682 by screws. The bearing part 681 is a deep groove ball bearing and has an inner ring for fixing the intermediate rotational transmission member 623, an outer ring for fixing the bearing retaining part 682, and a plurality of balls sandwiched between them. Thus, by using a deep groove ball bearing as the bearing part 681, the manufacturing cost of the robot 10 can be effectively reduced, and the robot 10 can be provided more cheaply. Furthermore, since the deep groove ball bearing has a simple and small structure, the robot 10 can also be miniaturized and lightweight. However, the configuration of the retaining part 68 is not particularly limited as long as the intermediate rotational transmission member 623 can be rotatably held in the bottom 51. For example, the bearing part 681 can also be a cylindrical roller bearing, an angular contact ball bearing, etc. Furthermore, for example, the intermediate rotational transmission member 623 can also be rotatably held in the support part 69 by the retaining part 68. Furthermore, the intermediate rotation transmission component 623 can also be rotatably supported at both ends by a pair of retaining parts 68 by the bottom 51 and the support part 69.

[0090] In addition, such as Figure 13As shown, the intermediate rotary transmission component 623 has a third rotary transmission component 623a and a fourth rotary transmission component 623b arranged side-by-side and concentrically on each other in the Z-axis direction. The diameter of the third rotary transmission component 623a is larger than that of the input-side rotary transmission component 621, that is, its outer diameter is larger. In addition, the third rotary transmission component 623a is positioned at the same height as the input-side rotary transmission component 621. Furthermore, a first annular component 624 is wound around the third rotary transmission component 623a and the input-side rotary transmission component 621. These components, including the input-side rotary transmission component 621, the third rotary transmission component 623a, and the first annular component 624, constitute the first-stage reduction mechanism.

[0091] On the other hand, the diameter of the fourth rotary transmission member 623b is smaller than that of the third rotary transmission member 623a and the output-side rotary transmission member 622, meaning its outer diameter is smaller. Furthermore, the fourth rotary transmission member 623b is positioned at the same height as the output-side rotary transmission member 622. Moreover, a second annular member 625 is wound around both the fourth rotary transmission member 623b and the output-side rotary transmission member 622. These components—the fourth rotary transmission member 623b, the output-side rotary transmission member 622, and the second annular member 625—constitute the second-stage reduction mechanism.

[0092] In this configuration, the rotation of the output shaft 611 is transmitted to the third rotation transmission member 623a via the input-side rotation transmission member 621 and the first annular member 624, while the intermediate rotation transmission member 623 rotates around the rotation axis B2. Furthermore, the rotation of the intermediate rotation transmission member 623 is transmitted to the output-side rotation transmission member 622 via the fourth rotation transmission member 623b, and the output-side rotation transmission member 622 rotates together with the end shaft 125 around the rotation axis A5. Thus, the power transmission unit 62 has a total of two-stage reduction mechanisms, enabling the rotation of the output shaft 611 to be reduced in two stages, allowing the end shaft 125 to rotate with a greater torque. In addition, because the reduction ratio of the power transmission unit 62 is large, a high-speed motor 61 can be used. Since higher-speed motors have lower drive currents and tend to be smaller, the motor 61 can be miniaturized. Therefore, the end weight of the robotic arm 120 is suppressed, and the vibration of the robotic arm 120 can be effectively suppressed.

[0093] However, as long as the power transmission unit 62 can transmit the rotation of the output shaft 611 to the end shaft 125, there are no particular limitations. For example, the power transmission unit 62 may not be a speed reducer. It can transmit the rotation of the output shaft 611 to the end shaft 125 at the same speed, or it can accelerate the rotation of the output shaft 611 and transmit it to the end shaft 125.

[0094] It should be noted that the combination of the rotary transmission components 621, 622, 623 and the annular components 624, 625 is not particularly limited; for example, pulleys / belts, sprockets / chains, wheels / wires, etc., can be listed. However, in this embodiment, pulleys / belts are used. With this configuration, since no lubricating grease or oil is used in the power transmission section 62, there is no possibility of lubricating grease or oil scattering onto the workpiece. Therefore, the robot 10 can be applied to food manufacturing.

[0095] In addition, such as Figure 14 As shown, when viewed from above along the rotation axis A5 (Z-axis), rotation axis A5 and rotation axis A1 are arranged side-by-side in the Y-axis direction. Furthermore, the rotation axis B1 of the output shaft 611 and the rotation axis B2 of the intermediate rotation transmission component 623 are located on opposite sides of the virtual straight line LL connecting rotation axes A5 and A1. In this embodiment, rotation axis B2 is located on the positive side of the virtual straight line LL in the X-axis direction, and rotation axis B1 is located on the negative side in the X-axis direction. This configuration allows for a well-balanced arrangement of the end-effector 125, motor 61, and power transmission component 62 on the fourth arm 124, minimizing the weight difference between the portion closer to the positive side of the X-axis direction than the virtual straight line LL and the portion closer to the negative side of the X-axis direction than the virtual straight line LL. Therefore, the twisting of the robotic arm 120 during operation can be effectively suppressed, improving the robot 10's stability, i.e., motion accuracy. As a result, the cycle time of operations can be shortened, and productivity is increased.

[0096] Furthermore, when viewed from above along the rotation axis A5 (Z-axis), rotation axes B1 and B2 are located between rotation axes A5 and A1 in the Y-axis direction. In other words, compared to rotation axis A5, rotation axes B1 and B2 are located closer to rotation axis A1. With this configuration, the center of gravity of the fourth arm 124 can be moved closer to the rotation axis A1, reducing the inertia of the robotic arm 120 about rotation axis A1. Therefore, the load torque of the robotic arm 120 is reduced, and the stability of the robot 10 is improved. However, this is not a limitation; for example, at least one of rotation axes B1 and B2 may not be located between rotation axes A5 and A1.

[0097] Furthermore, when viewed from above along the rotation axis A5 (Z-axis), the rotation axis A4 is located between rotation axis A5 and rotation axis A1. Also, rotation axes B1 and B2 are located between rotation axis A5 and rotation axis A4 in the Y-axis direction. With this configuration, the motor 61 and the intermediate rotation transmission member 623 are not excessively separated from the rotation axis A5. Therefore, the end shaft 125, motor 61, and intermediate rotation transmission member 623 can be compactly arranged, enabling miniaturization of the fourth arm 124. However, this is not a limitation; for example, at least one of the rotation axes B1 and B2 may not be located between rotation axis A5 and rotation axis A4.

[0098] In particular, in this embodiment, rotating shafts B1 and B2 are positioned further away from rotating shaft A4 than rotating shaft A5. That is, in the Y-axis direction, the separation distance between rotating shaft B1 and rotating shaft A4 is shorter than the separation distance between rotating shaft B1 and rotating shaft A5, and the separation distance between rotating shaft B2 and rotating shaft A4 is shorter than the separation distance between rotating shaft B2 and rotating shaft A5. With this configuration, rotating shaft A5 is appropriately separated from rotating shafts B1 and B2, making it easier to increase the outer diameter of the output-side rotation transmission member 622 and the third rotation transmission member 623a. Therefore, the power transmission unit 62 can be configured as a reducer with a larger reduction ratio.

[0099] Furthermore, when viewed from above along the rotation axis A5 (Z-axis), rotation axis B2 is located between rotation axis A5 and rotation axis B1 in the Y-axis direction. That is, in the Y-axis direction, the isolation distance between rotation axis B2 and rotation axis A5 is shorter than the isolation distance between rotation axis B1 and rotation axis A5. With this configuration, the intermediate rotation transmission component 623, whose top-view shape is easily enlarged compared to motor 61, is less likely to extend from the arm base 50. Therefore, contact between the intermediate rotation transmission component 623 and other parts is suppressed, and the drive of robot 10 is stable. However, this is not a limitation; rotation axis B2 may not be located between rotation axis A5 and rotation axis B1.

[0100] Furthermore, when viewed from above along the rotation axis A5 (Z-axis), the opening on the upper side of the through hole 125a formed in the end shaft portion 125, that is, the base end side, does not overlap with the power transmission portion 62. In other words, when viewed from above (positive side in the Z-axis direction), the opening on the upper side of the through hole 125a exposes the motor 61, the input-side rotary transmission member 621 constituting the power transmission portion 62, the output-side rotary transmission member 622, the intermediate rotary transmission member 623, the first annular member 624, and the second annular member 625. With this configuration, wiring and pipe laying of the through hole 125a become easier. However, it is not limited to this; at least a portion of the opening on the upper side of the through hole 125a may overlap with the motor 61 or the power transmission portion 62.

[0101] The above provides an explanation of each arm 121 to 124.

[0102] like Figure 1 As shown, the robot 10 further includes: a first drive unit 140 for rotating the first arm 121 relative to the base 110 about a rotation axis A1; a second drive unit 150 for rotating the second arm 122 relative to the first arm 121 about a rotation axis A2; and a third drive unit 160 for rotating the third arm 123 relative to the second arm 122 about a rotation axis A3. Additionally, the robot 10 includes: a linkage mechanism 131 for transmitting the power output from the third drive unit 160 to the third arm 123; and a linkage mechanism 132 for maintaining the fourth arm 124 in a constant posture regardless of the postures of the second arm 122 and the third arm 123. It should be noted that the "constant posture" refers to... Figure 1 Rotate axis A5 in that orientation along the Z-axis.

[0103] like Figure 15 As shown, the first drive unit 140 is disposed within the base 110. Such a first drive unit 140 includes: a motor 141 having an output shaft 141a that rotates about the Z-axis; and a power transmission unit 142 that transmits the rotation of the motor 141 to the first arm 121.

[0104] The motor 141 is, for example, a servo motor, particularly a three-phase motor driven by three-phase AC, and is fixed to the base 110.

[0105] The power transmission unit 142 is a speed reducer and includes: an input-side rotary transmission member 142a fixed to the output shaft 141a; an output-side rotary transmission member 142b fixed to the first arm 121, with a diameter larger than that of the input-side rotary transmission member 142a; and an annular member 142c wrapped around the input-side rotary transmission member 142a and the output-side rotary transmission member 142b. It should be noted that the combination of the input and output-side rotary transmission members 142a, 142b / annular member 142c is not particularly limited; examples include pulleys / belts, sprockets / chains, wheels / wires, etc., but a pulley / belt is used in this embodiment.

[0106] In this configuration, the rotation of the output shaft 141a is transmitted to the output side rotation transmission member 142b via the input side rotation transmission member 142a and the annular member 142c. The output side rotation transmission member 142b and the first arm 121 rotate integrally around the rotation axis A1. In this way, by using the reducer as the power transmission unit 142, the rotation of the output shaft 141a can be reduced, while the first arm 121 can be rotated with a sufficiently large torque.

[0107] The first drive unit 140 has been described above, but its configuration is not particularly limited. For example, the power transmission unit 142 may be a gear mechanism such as a planetary gear or a wave gear. Furthermore, for example, in this embodiment, the power transmission unit 142 is configured as a single-stage reducer, but it may also be configured as a two-stage or more reducer. To briefly illustrate a two-stage reducer, for example, an intermediate rotary transmission member, having a first rotary transmission member with a diameter larger than that of the input-side rotary transmission member 142a and a second rotary transmission member with a diameter smaller than that of the output-side rotary transmission member 142b, is configured to rotate about the Z-axis. An annular member is wound around the input-side rotary transmission member 142a and the first rotary transmission member, thereby forming a first reducer; the annular member is wound around the second rotary transmission member and the output-side rotary transmission member 142b, thereby forming a second reducer, thus forming a two-stage reducer. Similarly, two or more intermediate rotary transmission members may be configured to form a three-stage or more reducer.

[0108] like Figure 2 As shown, the second drive unit 150 and the third drive unit 160 are respectively disposed within the first arm 121. It should be noted that the second drive unit 150 and the third drive unit 160 have the same configuration as the aforementioned first drive unit 140.

[0109] The second drive unit 150 includes: a motor 151 having an output shaft 151a that rotates about an X-axis; and a power transmission unit 152 that transmits the rotation of the motor 151 to the second arm 122. The motor 151 is, for example, a servo motor, particularly a three-phase motor driven by three-phase AC, and is fixed to the arm base 20.

[0110] The power transmission unit 152 is a speed reducer and includes an input-side rotary transmission component 152a fixed to the output shaft 151a, an output-side rotary transmission component 152b fixed to the shaft 21 and having a diameter larger than that of the input-side rotary transmission component 152a, and an annular component 152c wound around the input-side rotary transmission component 152a and the output-side rotary transmission component 152b. It should be noted that the combination of the input and output-side rotary transmission components 152a, 152b / annular component 152c is not particularly limited; for example, pulleys / belts, sprockets / chains, wheels / wires, etc., can be listed. However, in this embodiment, a pulley / belt is used.

[0111] In this configuration, the rotation of the output shaft 151a is transmitted to the output side rotation transmission member 152b via the input side rotation transmission member 152a and the annular member 152c. The output side rotation transmission member 152b and the shaft 21 rotate integrally around the rotation axis A2. Consequently, the second arm 122, fixed to the shaft 21, rotates relative to the first arm 121 around the rotation axis A2. Thus, by using a speed reducer as the power transmission unit 152, the rotation of the output shaft 151a can be reduced, while the second arm 122 can be rotated with a sufficiently large torque.

[0112] The second drive unit 150 has been described above, but its configuration is not particularly limited. For example, the power transmission unit 152 may be a gear device such as a planetary gear or a wave gear. In addition, for example, in this embodiment, the power transmission unit 152 is composed of a single-stage reducer, but it may also be composed of a two-stage or higher reducer, similar to the first drive unit 140 described above.

[0113] like Figure 2 As shown, the third drive unit 160 includes: a motor 161 having an output shaft 161a that rotates about the X-axis; and a power transmission unit 162 that transmits the rotation of the motor 161 to the third arm 123 via a linkage mechanism 131. The motor 161 is, for example, a servo motor, particularly a three-phase motor driven by three-phase AC, and is fixed to the arm base 20.

[0114] The power transmission unit 162 is a speed reducer and includes: an input-side rotary transmission member 162a fixed to the output shaft 161a; an output-side rotary transmission member 162b rotatably held on the shaft 21 via a bearing portion 163, and having a diameter larger than that of the input-side rotary transmission member 162a; and an annular member 162c wrapped around the input-side rotary transmission member 162a and the output-side rotary transmission member 162b. It should be noted that the combination of the input and output-side rotary transmission members 162a and 162b / annular member 162c is not particularly limited; examples include pulleys / belts, sprockets / chains, wheels / wires, etc. In this embodiment, a pulley / belt is used.

[0115] In this configuration, the rotation of the output shaft 161a is transmitted to the output-side rotation transmission member 162b via the input-side rotation transmission member 162a and the annular member 162c. The output-side rotation transmission member 162b rotates about the rotation axis A2 relative to the shaft 21. Then, the rotation of the output-side rotation transmission member 162b is transmitted to the third arm 123 via the linkage mechanism 131. The third arm 123 rotates about the rotation axis A3 relative to the second arm 122. In this way, by using the reducer as the power transmission unit 162, the rotation of the output shaft 161a can be reduced, while the third arm 123 can be rotated with a sufficiently large torque.

[0116] The third drive unit 160 has been described above, but its configuration is not particularly limited. For example, the power transmission unit 162 may be a gear device such as a planetary gear or a wave gear. In addition, for example, in this embodiment, the power transmission unit 162 is composed of a single-stage reducer, but it may also be composed of a two-stage or higher reducer, similar to the first drive unit 140 described above.

[0117] like Figure 16 As shown, the linkage mechanism 131 for transmitting the rotation of the output-side rotation transmission component 162b to the third arm 123 includes a link 131a, a link 131b, and pivots 131c and 131d.

[0118] Link 131a is plate-shaped with the X-axis as its normal and extends in a direction orthogonal to the rotation axis A2. Link 131a is fixed at its base end to the output-side rotation transmission member 162b of the power transmission unit 162. Link 131b is rod-shaped, extending in a direction orthogonal to the rotation axis A2, and is arranged parallel to the second arm 122. Link 131b is connected at its base end to the end of link 131a via pivot 131c, allowing it to rotate about an axis J1 parallel to the rotation axis A2. It should be noted that axis J1 is isolated from the rotation axis A2. Furthermore, link 131b is connected at its end to the base end of the third arm 123 via pivot 131d, allowing it to rotate about an axis J2 parallel to the rotation axis A3. It should be noted that axis J2 is isolated from the rotation axis A3.

[0119] In this linkage mechanism 131, when viewed from the X-axis, a parallelogram Q1 is formed with rotation axes A2, A3 and axes J1, J2 as vertices. In this parallelogram Q1, the line Q11 connecting rotation axes A2 and J1 and the line Q12 connecting rotation axes A3 and J2 remain parallel even when deformed. Therefore, when the linkage 131a rotates about rotation axis A2, the third arm 123 rotates about rotation axis A3 while maintaining the parallelism of lines Q11 and Q12.

[0120] The linkage mechanism 131 has been described above. However, as long as the third arm 123 can rotate relative to the second arm 122 about the rotation axis A3, there are no particular limitations on the configuration of the linkage mechanism 131.

[0121] Next, the linkage mechanism 132 will be described. For example... Figure 16As shown, linkage 132 is a mechanism for maintaining the posture of the fourth arm 124 in a constant manner, ensuring that the rotation axis A5 is always along the Z-axis, regardless of the postures of the second arm 122 and the third arm 123. Such linkage 132 has links 132a, 132b, 132c and pivots 132d, 132e, 132f, 132g.

[0122] Link 132a is a rod-shaped rod extending in a direction orthogonal to the rotation axis A2, and is arranged side by side with the second arm 122. Furthermore, link 132a is connected at its base end to the upper end of the first arm 121 via a pivot 132d in a manner rotatable about an axis J3 parallel to the rotation axis A2. It should be noted that axis J3 is isolated from the rotation axis A2.

[0123] Link 132b is a triangular plate with the X-axis as its normal, and at one corner, it is rotatably held to shaft 31 via a third connecting part 34. Furthermore, at its base end, link 132b is connected to the end of link 132a via pivot 132e, allowing it to rotate about axis J4, which is parallel to the rotation axis A3. It should be noted that axis J4 is isolated from the rotation axis A3.

[0124] Link 132c is a rod-shaped rod extending in a direction orthogonal to the rotation axis A3, and is arranged parallel to the third arm 123. Furthermore, link 132c is connected at its base end to the corner of the end of link 132b via pivot 132f, allowing it to rotate about an axis J5 parallel to the rotation axis A3. It should be noted that axis J5 is isolated from the rotation axis A3. Moreover, link 132c is connected at its end end to the base of the fourth arm 124 via pivot 132g, allowing it to rotate about an axis J6 parallel to the rotation axis A4. It should be noted that axis J6 is isolated from the rotation axis A4. In other words, link 132c connects the position of link 132b offset from the rotation axis A3 and the position of the fourth arm 124 offset from the rotation axis A4.

[0125] In this linkage mechanism 132, when viewed from the X-axis, a parallelogram Q2 is formed with rotation axes A2, A3 and axes J3, J4 as vertices. In this parallelogram Q2, the line Q21 connecting rotation axes A2 and J3 and the line Q22 connecting rotation axes A3 and J4 remain parallel even when deformed. Furthermore, when viewed from the X-axis, a parallelogram Q3 is formed with rotation axes A3, A4 and axes J5, J6 as vertices. In this parallelogram, the line Q31 connecting rotation axes A3 and J5 and the line Q32 connecting rotation axes A4 and J6 remain parallel even when deformed.

[0126] Furthermore, the tilt of line Q21 relative to the Z-axis is constant and independent of the orientation of the second and third arms 122 and 123. Therefore, the tilt of line Q22, which is paired with line Q21, is also constant and independent of the orientation of the second and third arms 122 and 123. As a result, the orientation of link 132b is also constant. Additionally, since the orientation of link 132b is constant, the orientation of paired lines Q31 and Q32 is also constant and independent of the orientation of the second and third arms 122 and 123. Therefore, regardless of the orientation of the second and third arms 122 and 123, the fourth arm 124 is maintained in a constant orientation, that is, the orientation of the rotation axis A5 along the Z-axis. Thus, by forming a configuration that mechanically maintains the orientation of the fourth arm 124 as constant, electrical control is not required, and the control of the robot 10 becomes easier. It should be noted that "maintaining the orientation of the fourth arm 124 as constant" means allowing slight orientation changes, such as changes within a range of less than 5 degrees relative to the Z-axis.

[0127] The linkage mechanism 132 has been described above. In this linkage mechanism 132, the portion of the link 132b between the first connecting portion 32 and the second connecting portion 33 is connected to the shaft 31. With this configuration, since the extension of the link 132b to the side of the third arm 123 is suppressed, miniaturization of the robot 10 can be achieved. Furthermore, the center of gravity of the robotic arm 120 is less likely to deviate in the X-axis direction relative to the rotation axis A1, thus improving the weight balance of the robotic arm 120.

[0128] Furthermore, when viewed from above in a direction orthogonal to the long side of the third arm 123 (which is the X-axis direction along the rotation axis A3 and the direction parallel to rotation axes A3 and A4), the link 132c overlaps with the third arm 123. In other words, the link 132c is located between the side plates 42 and 43. With this configuration, the extension of the link 132c to the side of the third arm 123 is suppressed, thus enabling miniaturization of the robot 10. Additionally, the center of gravity of the robotic arm 120 is less likely to deviate from the X-axis direction relative to the rotation axis A1, improving the weight balance of the robotic arm 120.

[0129] The robot system 1 has been described above. As previously mentioned, such a robot system 1 includes a robot 10 with a robotic arm 120, wherein the robotic arm 120 comprises: a fourth arm 124 as a first arm; and a third arm 123 as a second arm, connected to the fourth arm 124 and rotating relative to the fourth arm 124 about a rotation axis A4 as a first rotation axis. Furthermore, the fourth arm 124 has: a shaft 54 ​​along the rotation axis A4; and mounting portions 57 and 58 disposed on the shaft 54 ​​and detachably connected to the third arm 123. Additionally, the third arm 123 has slit-shaped shaft through holes 422 and 432, into which the shaft 54 ​​is inserted radially V from the shaft 54, and the slit-shaped shaft through holes 422 and 432 position the shaft 54 ​​relative to the third arm 123. Furthermore, after being positioned by the shaft through holes 422 and 432, shaft 54 ​​is connected to the third arm 123 via mounting portions 57 and 58, and rotates relative to at least one of the fourth arm 124 and the third arm 123 (the fourth arm 124 in this embodiment). With this configuration, it becomes easy to attach and detach the fourth arm 124 from the third arm 123. Therefore, the assemblability and maintainability of the robot 10 are improved.

[0130] Furthermore, as mentioned above, the mounting portions 57 and 58 are flanges that protrude radially toward the shaft 54. With this configuration, the mounting portions 57 and 58 are simplified and can be easily fixed to the third arm 123 around the shaft 54.

[0131] Furthermore, the mounting portions 57 and 58 are formed as separate entities from the shaft 54. This configuration facilitates the formation of the mounting portions 57 and 58. Consequently, the freedom in determining the shape and material of the shaft 54 ​​and the mounting portions 57 and 58 is increased.

[0132] Alternatively, as mentioned above, at least one of the mounting portions 57 and 58 may be integrally formed with the shaft 54. Even with such a configuration, at least one of the mounting portions 57 and 58 can be easily formed. Furthermore, since there is no need to fix at least one of the mounting portions 57 and 58 to the shaft 54, the assembly of the robot 10 becomes easier. In addition, since there is no deviation of at least one of the mounting portions 57 and 58 relative to the shaft 54, the drive of the robot 10 remains stable over a long period.

[0133] Furthermore, as mentioned above, the robot 10 has a limiting part 500 that restricts the deviation of the fourth arm 124 and the third arm 123 in the direction along the rotation axis A4. With this configuration, it is possible to suppress the decrease in positional accuracy caused by the deviation of the fourth arm 124 and the third arm 123 in the direction along the rotation axis A4. In addition, torsion of each part can be effectively suppressed, ensuring long-term stable operation of the robot 10.

[0134] Furthermore, as mentioned earlier, the fourth arm 124 is located at the end of the robotic arm 120 relative to the third arm 123. This configuration facilitates the assembly and disassembly of the fourth arm 124.

[0135] Furthermore, as described above, the fourth arm 124 has a pair of shaft retaining portions 55 and 56 disposed on the shaft 54 ​​and separated in the direction along the rotation axis A4. The portion of the shaft 54 ​​between the pair of shaft retaining portions 55 and 56 is fixed to the third arm 123 by a mounting portion 57. With this configuration, since the central portion of the shaft 54 ​​is supported by the third arm 123, the shaft 54 ​​is less prone to bending. Therefore, the rotation axis A4 is less likely to vibrate, and the rotation of the fourth arm 124 is stable.

[0136] Second Implementation Method

[0137] Figure 17 This is a partial cross-sectional view of the fourth arm of the robot according to the second embodiment. Figure 18 and Figure 19 These are side views showing the steps of mounting the fourth arm onto the third arm.

[0138] This embodiment differs primarily in the configuration of the third arm 123 and the fourth arm 124; otherwise, it is identical to the first embodiment described above. It should be noted that in the following description, this embodiment will be described primarily in terms of its differences from the first embodiment, while identical details will be omitted. Furthermore, in the figures of this embodiment, the same reference numerals are used to label configurations identical to those in the previous embodiment. It should be noted that, in this embodiment, unlike the first embodiment, the fourth arm 124 is the "second arm" of the invention, and the third arm 123 is the "first arm" of the invention.

[0139] In the robot 10 of this embodiment, as Figure 17 As shown, with the shaft 54 ​​passing through the shaft through holes 422 and 432 of the third arm, it is rotatably held in the third arm 123 by a pair of shaft retaining parts 55 and 56. Specifically, the shaft 54 ​​is screwed to the side plate 42 around the shaft through hole 422 by the shaft retaining part 55, and is screwed to the side plate 43 around the shaft through hole 432 by the shaft retaining part 56. It should be noted that, in this embodiment, the shaft through holes 422 and 432 may also be closed holes.

[0140] Additionally, the third arm 123 has a pair of mounting portions 57 and 58 disposed on the shaft 54. One mounting portion 57 is located outside the shaft holding portion 55, that is, on the positive side in the X-axis direction, and the other mounting portion 58 is located between the shaft holding portions 55 and 56. That is, on the shaft 54, the mounting portion 57, the shaft holding portion 55, the mounting portion 58, and the shaft holding portion 56 are arranged side by side in sequence from the positive side in the X-axis direction. However, the arrangement of the shaft holding portions 55 and 56 and the mounting portions 57 and 58 is not particularly limited.

[0141] Furthermore, the shaft 54 ​​is detachably connected to the fourth arm 124 via mounting portions 57 and 58. Specifically, with the shaft 54 ​​passing through the slit-shaped shaft through holes 521 and 531 formed in the fourth arm 124, the mounting portion 57 is secured to the side plate portion 52 by multiple screws around the shaft 54; and the mounting portion 58 is secured to the side plate portion 53 by multiple screws around the shaft 54. By making the mounting portions 57 and 58 flange-shaped, their configuration is simplified, and they are easily secured to the fourth arm 124 around the shaft 54. However, this is not a limitation; for example, at least one of the mounting portions 57 and 58 may be integrally formed with the shaft 54. It should be noted that in this embodiment, to facilitate the operation of passing the shaft 54 ​​through the bearing portion 551, it is preferable that the mounting portion 57 is not integrally formed with the shaft 54, but only the mounting portion 58 is integrally formed with the shaft 54.

[0142] The steps for attaching the fourth arm 124 to the third arm 123 are explained below. First, as follows: Figure 18 As shown, the fourth arm 124 is displaced radially V relative to the shaft 54 ​​disposed on the third arm 123, and the shaft 54 ​​is inserted into the shaft through holes 521 and 531 of the fourth arm 124. Then, as... Figure 19 As shown, the outer peripheral surface of shaft 54 ​​is brought into contact with the bottom of shaft through holes 521 and 531. This positions the fourth arm 124 relative to shaft 54, allowing it to be correctly positioned relative to the rotation axis A4. Next, maintaining this state, mounting portions 57 and 58 and arm base 50 are secured with screws. Specifically, mounting portions 57 and side plate 52 are secured with screws, and mounting portions 58 and side plate 53 are secured with screws. Through this process, the fourth arm 124 is attached to the third arm 123. It should be noted that when removing the fourth arm 124 from the third arm 123, the reverse steps are performed. Thus, the fourth arm 124 can be attached to the third arm 123 simply by removing and installing screws on the arm base 50. This improves the assemblability and maintainability of the robot 10. Furthermore, since only the fourth arm 124 can be removed, its maintainability is improved.

[0143] As described above, the robot 10 of this embodiment has a robotic arm 120, which includes a third arm 123 as a first arm and a fourth arm 124 as a second arm, connected to the third arm 123 and rotating relative to the third arm 123 about a rotation axis A4 as a first rotation axis. The third arm 123 has a shaft 54 ​​along the rotation axis A4 and mounting portions 57 and 58 disposed on the shaft 54 ​​and detachably connected to the fourth arm 124. The fourth arm 124 has slit-shaped shaft through holes 521 and 531, through which the shaft 54 ​​is inserted radially V into the slit-shaped shaft through holes 521 and 531, and the slit-shaped shaft through holes 521 and 531 position the shaft 54 ​​relative to the fourth arm 124. Furthermore, after being positioned by the shaft through holes 521 and 531, shaft 54 ​​is connected to the fourth arm 124 via mounting portions 57 and 58, and rotates relative to at least one of the third arm 123 and the fourth arm 124 (the third arm 123 in this embodiment). With this configuration, it becomes easier to attach and detach the fourth arm 124 from the third arm 123. Therefore, the assembleability and maintainability of the robot 10 are improved.

[0144] Furthermore, as mentioned earlier, the fourth arm 124 is located at the end of the robotic arm 120 relative to the third arm 123. This configuration facilitates the assembly and disassembly of the fourth arm.

[0145] Even with this second implementation method, the same effect as the first implementation method described above can be achieved.

[0146] The robot of the present invention has been described above with reference to the illustrated embodiments, but the present invention is not limited thereto. Furthermore, the various parts of the robot can be replaced with any structure that can perform the same function. Additionally, any structure can be added to the robot.

[0147] Furthermore, for example, the shape of the shaft through holes 422 and 432 in the first embodiment described above is not particularly limited as long as the shaft 54 ​​can be inserted and the shaft 54 ​​can be positioned by surface contact or two or more isolated point contacts. For example, it could also be... Figures 20 to 22 The shape shown. Figure 20 The shaft through holes 422 and 432 are semi-circular cuts opening at the end faces of the side plate portions 42 and 43. With this configuration, the shaft 54 ​​can be positioned at the very end of the third arm 123. Therefore, while limiting the overall length of the arm 123, the isolation distance between the rotating shaft A2 and the rotating shaft A3 can be increased. Furthermore, Figure 21The shaft through holes 422 and 432 are rectangular cuts that open onto the end faces and lower surfaces of the side plate portions 42 and 43. With this configuration, the openings of the shaft through holes 422 and 432 are widened, making it easier to insert the shaft 54 ​​into the shaft through holes 422 and 432. Figure 22 The shaft passes through holes 422 and 432, which are rectangular cuts that open onto the lower surfaces of the side plate portions 42 and 43.

[0148] Alternatively, for example, the mounting parts 57 and 58 may be configured as bearing structures such as shaft retaining parts 55 and 56, and the shaft 54 ​​may be rotatable relative to both the third arm 123 and the fourth arm 124.

Claims

1. A robot, characterized in that, have: A robotic arm includes: a first arm; and a second arm connected to the first arm and rotating relative to the first arm about a first rotation axis. The first arm has: a shaft along the first rotation axis; and a mounting portion disposed on the shaft and detachably connected to the second arm. The second arm has a slit-shaped shaft through hole into which the shaft is inserted radially, and the slit-shaped shaft through hole positions the shaft relative to the second arm. The shaft, after being positioned by the shaft through the hole, is connected to the second arm via the mounting part and rotates relative to at least one of the first arm and the second arm.

2. The robot according to claim 1, characterized in that, The mounting portion is a flange that protrudes radially from the axis relative to the axial direction.

3. The robot according to claim 2, characterized in that, The mounting portion is integrally formed with the shaft.

4. The robot according to claim 2, characterized in that, The mounting part and the shaft are formed as separate entities.

5. The robot according to claim 1, characterized in that, The robot has a limiting part that restricts the first arm and the second arm from deviating in a direction along the first rotation axis.

6. The robot according to claim 1, characterized in that, The first arm is located at the end of the robotic arm relative to the second arm.

7. The robot according to claim 1, characterized in that, The second arm is located at the end of the robotic arm relative to the first arm.

8. The robot according to claim 1, characterized in that, The first arm has a pair of shaft retaining portions, which are disposed on the shaft and spaced apart in the direction along the first rotation axis. The portion of the shaft between the pair of shaft retainers is fixed to the second arm via the mounting portion.

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