Vertical multi-joint robot

Abstract

To provide a vertical multi-joint robot which can reduce a moment of inertia of a robot arm.SOLUTION: A vertical multi-joint robot has a base, a first arm rotated around a vertical axis to the base, a second arm which is connected to the first arm and is rotated around a first horizontal axis to the first arm, a third arm which is connected to the second arm and is rotated around a second horizontal axis to the second arm, a first motor for rotating the second arm with respect to the first arm around the first horizontal axis, and a second motor for rotating the third arm with respect to the second arm around the second horizontal axis. The first motor and the second motor are each arranged on the first arm.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vertically articulated robot. [Background technology]

[0002] The robot described in Patent Document 1 has a robot main body including a base and a robot arm connected to the base. The robot arm has a first arm rotatably connected to the base, a second arm rotatably connected to the first arm, a third arm rotatably connected to the second arm, a fourth arm rotatably connected to the third arm, a fifth arm rotatably connected to the fourth arm, and a sixth arm rotatably connected to the fifth arm.

[0003] Furthermore, the robot described in Patent Document 1 has a first motor that rotates the first arm relative to the base, a second motor that rotates the second arm relative to the first arm, a third motor that rotates the third arm relative to the second arm, a fourth motor that rotates the fourth arm relative to the third arm, a fifth motor that rotates the fifth arm relative to the fourth arm, and a sixth motor that rotates the sixth arm relative to the fifth arm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-063933 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the robot described in Patent Document 1, the second and third motors, which are heavy, are located in the center of the second arm in the longitudinal direction, which makes it difficult to reduce the weight of the tip of the robot arm, and the moment of inertia of the robot arm tends to increase. [Means for solving the problem]

[0006] The vertical articulated robot of the present invention comprises: a base; a first arm that rotates about a vertical axis relative to the base; a second arm connected to the first arm and rotatable about a first horizontal axis relative to the first arm; a third arm connected to the second arm and rotatable about a second horizontal axis relative to the second arm; a first motor that rotates the second arm about the first horizontal axis relative to the first arm; a second motor that rotates the third arm about the second horizontal axis relative to the second arm, The first motor and the second motor are each disposed on the first arm. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a vertical articulated robot according to a first embodiment. FIG. [Figure 2] 2 is a schematic diagram showing the joints of the vertical articulated robot shown in FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view showing a first power transmission mechanism. [Figure 4] FIG. 4 is a cross-sectional view showing a second power transmission mechanism. [Figure 5] FIG. 4 is a cross-sectional view showing a second power transmission mechanism. [Figure 6] FIG. 2 is a side view showing the arrangement of a first motor and a second motor. [Figure 7] FIG. 10 is a cross-sectional view showing a vertical articulated robot according to a second embodiment. [Figure 8] FIG. 2 is a side view showing the arrangement of a first motor and a second motor. [Figure 9] FIG. 10 is a cross-sectional view showing a vertical articulated robot according to a third embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a vertical articulated robot according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vertical articulated robot according to the present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings.

[0009] For ease of explanation, each figure illustrates three mutually orthogonal axes as the X-axis, Y-axis, and Z-axis. For ease of explanation, the direction parallel to the X-axis will be referred to as the "X-axis direction," the direction parallel to the Y-axis will be referred to as the "Y-axis direction," and the direction parallel to the Z-axis will be referred to as the "Z-axis direction." The XY plane defined by the X-axis and Y-axis is along the horizontal plane, and the Z-axis direction is along the vertical direction. Therefore, hereinafter, the direction along the XY plane will also be referred to as the horizontal direction, and the arrow side of the Z-axis will be referred to as "up" and the opposite side as "down." In this specification, "horizontal" refers not only to a completely horizontal position but also to a position that can be considered equivalent to horizontal in terms of technical common sense, for example, a position tilted within ±5° from the horizontal. Similarly, "vertical" refers not only to a completely vertical position but also to a position that can be considered equivalent to vertical in terms of technical common sense, for example, a position tilted within ±5° from the vertical.

[0010] First Embodiment Fig. 1 is a perspective view showing a vertical articulated robot according to a first embodiment. Fig. 2 is a schematic diagram showing joints of the vertical articulated robot shown in Fig. 1. Fig. 3 is a cross-sectional view showing a first power transmission mechanism. Figs. 4 and 5 are cross-sectional views showing a second power transmission mechanism. Fig. 6 is a side view showing the arrangement of a first motor and a second motor.

[0011] 1 and 2 includes a base 11 and a robot arm 12 rotatably connected to the base 11. The base 11 is fixed to the floor, for example. The robot arm 12 also has a first arm 121 rotatably connected to the base 11 around a first rotation axis J1, which is a vertical axis extending vertically relative to the base 11; a second arm 122 rotatably connected to the first arm 121 around a second rotation axis J2, which is a first horizontal axis extending horizontally relative to the first arm 121; a third arm 123 rotatably connected to the second arm 122 around a third rotation axis J3, which is a second horizontal axis extending horizontally relative to the second arm 122; a fourth arm 124 rotatably connected to the third arm 123 around a fourth rotation axis J4; a fifth arm 125 rotatably connected to the fourth arm 124 around a fifth rotation axis J5, which is horizontally relative to the fourth arm 124; and a sixth arm 126 rotatably connected to the fifth arm 125 around a sixth rotation axis J6.

[0012] As shown in FIG. 1, the second arm 122 is connected to the first arm 121 from one side in the direction along the second rotation axis J2. In the illustrated example, the second arm 122 is connected to the first arm 121 from the positive side in the Y-axis direction. In other words, the second arm 122 is cantilevered at its base end by the first arm 121. This configuration allows the weight of the second arm 122 to be reduced. As a result, the weight of the entire robot arm 12 can be reduced, and the moment of inertia of the robot arm 12 can be reduced accordingly. Therefore, the robot arm 12 can be controlled with higher precision. The moment of inertia may also be referred to as inertia or moment of inertia.

[0013] As shown in FIG. 1, the second arm 122 is supported by the third arm 123 from one side in the direction along the third rotation axis J3. In the illustrated example, the second arm 122 supports the third arm 123 from the positive side in the Y-axis direction. In other words, the second arm 122 supports the third arm 123 in a cantilevered manner at its tip. This configuration allows the weight of the second arm 122 to be reduced. As a result, the weight of the entire robot arm 12 can be reduced, and the moment of inertia of the robot arm 12 can be reduced accordingly. Therefore, the robot arm 12 can be controlled with higher precision.

[0014] As shown in Figures 1 and 2, the vertical articulated robot 1 has a first drive unit 131 that rotates the first arm 121 around a first rotation axis J1 relative to the base 11, a second drive unit 132 that rotates the second arm 122 around a second rotation axis J2 relative to the first arm 121, a third drive unit 133 that rotates the third arm 123 around a third rotation axis J3 relative to the second arm 122, a fourth drive unit 134 that rotates the fourth arm 124 around a fourth rotation axis J4 relative to the third arm 123, a fifth drive unit 135 that rotates the fifth arm 125 around a fifth rotation axis J5 relative to the fourth arm 124, and a sixth drive unit 136 that rotates the sixth arm 126 around a sixth rotation axis J6 relative to the fifth arm 125. Each of the drive units 131 to 136 includes, for example, a motor as a drive source, a reducer that reduces the rotation of the motor to increase and output rotational force (torque), and an encoder that detects the amount of rotation of the motor.

[0015] 1, the vertical articulated robot 1 has a control board 14 and a power supply board 15 arranged in the base 11. However, the arrangement of the control board 14 and the power supply board 15 is not particularly limited.

[0016] The control board 14 independently controls the driving of the motors provided in each of the drive units 131 to 136. Such control board 14 includes a board on which wiring is provided, and a CPU (Central Processing Unit) which is an example of a processor, RAM (Random Access Memory), ROM (Read Only Memory) in which a program is stored, and the like, which are provided on the board. The CPU reads and executes the program stored in the ROM, thereby achieving the function of a control unit that controls the driving of the vertical articulated robot 1.

[0017] The power supply board 15 supplies power to the control board 14. The power supply board 15 includes a board on which wiring is provided, and a conversion circuit provided on the board for converting externally supplied power into a predetermined value. Note that the conversion circuit differs depending on the configuration of the vertical articulated robot 1, but examples of the conversion circuit include an AC / DC conversion circuit that converts an alternating current (AC) signal into a direct current (DC) signal, and a step-up circuit or step-down circuit that converts the voltage level of a signal.

[0018] The above is a brief description of the overall configuration of the vertical articulated robot 1. Next, we will explain in detail the second drive unit 132 and the third drive unit 133, which are characteristics of the vertical articulated robot 1. As mentioned above, the second drive unit 132 is a unit that rotates the second arm 122 about the second rotation axis J2 relative to the first arm 121, and the third drive unit 133 is a unit that rotates the third arm 123 about the third rotation axis J3 relative to the second arm 122.

[0019] First, we will explain the second drive unit 132. As shown in Fig. 3, the second drive unit 132 has a first motor 21 which is a motor with a built-in encoder, a first reducer 22 which connects the first arm 121 and the second arm 122, and a first power transmission mechanism 23 which connects the first motor 21 and the first reducer 22 and transmits the power of the first motor 21 to the first reducer 22.

[0020] The first motor 21 is disposed within the first arm 121. The first motor 21 is disposed such that its output shaft 211 is aligned with the second rotation axis J2. The first motor 21 is disposed such that its output shaft 211 is offset from the second rotation axis J2. In this embodiment, in a plan view from the Z axis direction, the first motor 21 is disposed at a position offset to the negative side in the X axis direction with respect to the second rotation axis J2. While there are no particular limitations on the first motor 21, in this embodiment it is a servo motor, particularly a three-phase motor driven by three-phase AC. By using a servo motor as the first motor 21, the drive of the second arm 122 can be controlled with high precision and ease.

[0021] The first reducer 22 is a strain wave gear device. By using a strain wave gear device as the first reducer 22, it is possible to reduce backlash in the first reducer 22. As a result, it is possible to control the second arm 122 with high precision. However, the first reducer 22 is not particularly limited, and may be a planetary gear device, a roller cam reduction device, or the like.

[0022] The first reducer 22 is mainly composed of a circular spline 221, a flexspline 222, and a wave generator 223. The circular spline 221 is fixed to the first arm 121, the flexspline 222 is fixed to the second arm 122, and the wave generator 223 is connected to the first motor 21 via the first power transmission mechanism 23. The wave generator 223 is cylindrical. Therefore, a through hole H1 is formed in the first reducer 22 along the second rotation axis J2, connecting the inside of the first arm 121 with the inside of the second arm 122. Wiring L electrically connects at least one of the control board 14 and the power supply board 15 to each drive unit of the robot arm 12. Note that if an inertial sensor is provided in the robot arm 12, the wiring L may include wiring that electrically connects at least one of the control board 14 and the power supply board 15 to the inertial sensor. As will be described later, a shaft 36 and a wire L are inserted through the through hole H1.

[0023] The first power transmission mechanism 23 is disposed within the first arm 121 together with the first motor 21. The first power transmission mechanism 23 has a first motor-side pulley 231 attached to the output shaft 211 of the first motor 21, a first reducer-side pulley 232 attached to the wave generator 223 which is the input shaft of the first reducer 22, and a first belt 233 wound around the first motor-side pulley 231 and the first reducer-side pulley 232.

[0024] In this configuration, the rotation of the first motor 21 is transmitted to the wave generator 223 of the first reducer 22 via the first motor-side pulley 231, the first belt 233, and the first reducer-side pulley 232, causing the wave generator 223 to rotate around the second rotation axis J2. Furthermore, the flexspline 222 rotates at a predetermined reduction ratio relative to the rotation of the wave generator 223, causing the second arm 122 to rotate around the second rotation axis J2 relative to the first arm 121.

[0025] In this manner, the power of the first motor 21 is transmitted to the first reducer 22 via the first power transmission mechanism 23, thereby increasing the degree of freedom in the placement of the first motor 21. In particular, the output shaft 211 of the first motor 21 can be positioned offset from the second rotation axis J2, effectively preventing the first motor 21 from overlapping with the through-hole H1 of the first reducer 22. This facilitates the insertion of the shaft 36 and the wiring L through the through-hole H1. Furthermore, for example, by adjusting the diameters of the first motor-side pulley 231 and the first reducer-side pulley 232, the first power transmission mechanism 23 can be used as a reducer. By using the first power transmission mechanism 23 in combination with the first reducer 22, a larger reduction ratio can be achieved. Furthermore, the use of two pulleys and a belt allows these to be formed from lightweight materials such as resin and rubber, thereby reducing the weight of the first power transmission mechanism 23.

[0026] However, the first power transmission mechanism 23 is not particularly limited, and may be configured, for example, by replacing the first motor-side pulley 231 and the first reducer-side pulley 232 with gears, and replacing the first belt 233 with a chain that meshes with these two gears. Alternatively, the chain may be omitted, and the gears may mesh directly with each other. However, compared to such a configuration using gears and a chain, the configuration using pulleys and belts as in this embodiment can reduce backlash in the first power transmission mechanism 23 and enable precise control of the second arm 122.

[0027] Next, the third drive unit 133 will be described. As shown in Figures 4 and 5, the third drive unit 133 has a second motor 31 which is a motor with a built-in encoder, a second reducer 32 which connects the second arm 122 and the third arm 123, and a second power transmission mechanism 33 which connects the second motor 31 and the second reducer 32 and transmits the power of the second motor 31 to the second reducer 32.

[0028] The second motor 31 is disposed within the first arm 121. The second motor 31 is disposed such that its output shaft 311 is aligned with the second rotation axis J2. The second motor 31 is disposed such that its output shaft 311 is offset from the second rotation axis J2. As shown in FIG. 3 , in this embodiment, the second motor 31 is disposed offset in the positive direction of the X axis with respect to the second rotation axis J2 in a plan view from the Z axis direction. While not particularly limited, the second motor 31 is a servo motor, particularly a three-phase motor driven by three-phase AC, similar to the first motor 21 described above. By using a servo motor as the second motor 31, the third arm 123 can be easily controlled with high precision.

[0029] The second reducer 32 is a strain wave gear device, similar to the above-described first reducer 22. By using a strain wave gear device as the second reducer 32, it is possible to reduce backlash in the second reducer 32. As a result, it is possible to control the third arm 123 with high precision. However, the second reducer 32 is not particularly limited, and may be a planetary gear device, a roller cam reduction device, or the like.

[0030] As shown in Fig. 5, the second reducer 32 is mainly composed of a circular spline 321, a flexspline 322, and a wave generator 323. The circular spline 321 is fixed to the second arm 122, the flexspline 322 is fixed to the third arm 123, and the wave generator 323 is connected to the second motor 31 via the second power transmission mechanism 33. The wave generator 323 is cylindrical. Therefore, the second reducer 32 is formed with a through hole H2 that runs along the third rotation axis J3 and connects the inside of the second arm 122 to the inside of the third arm 123. A wire L is inserted through the through hole H2.

[0031] As shown in FIGS. 4 and 5, the second power transmission mechanism 33 has a first transmission mechanism 34 arranged in the first arm 121 and a second transmission mechanism 35 arranged in the second arm 122.

[0032] The first transmission mechanism 34 has a second motor-side pulley 341 attached to the output shaft 311 of the second motor 31, a first intermediate pulley 342 supported rotatably about a second rotation axis J2 with respect to the first arm 121, and a second belt 343 passed around the second motor-side pulley 341 and the first intermediate pulley 342. On the other hand, the second transmission mechanism 35 has a second reducer-side pulley 351 attached to the wave generator 323 which is the input shaft of the second reducer 32, a second intermediate pulley 352 supported rotatably about the second rotation axis J2 with respect to the second arm 122, and a third belt 353 passed around the second reducer-side pulley 351 and the second intermediate pulley 352.

[0033] The second power transmission mechanism 33 also has a shaft 36 inserted through the through-hole H1 of the first reducer 22. The shaft 36 is disposed coaxially with the second rotation axis J2, with one end facing the inside of the first arm 121 and the other end facing the inside of the second arm 122. A first intermediate pulley 342 is fixed to one end of the shaft 36, and a second intermediate pulley 352 is fixed to the other end. That is, in the second power transmission mechanism 33, the first transmission mechanism 34 and the second transmission mechanism 35 are connected via the shaft 36. This configuration makes it possible to connect the first transmission mechanism 34 disposed in the first arm 121 and the second transmission mechanism 35 disposed in the second arm 122 with a simple configuration.

[0034] In this configuration, the rotation of the second motor 31 is transmitted to the first intermediate pulley 342 via the second motor-side pulley 341 and the second belt 343, causing the first intermediate pulley 342 and the second intermediate pulley 352 to rotate integrally around the second rotation axis J2. The rotation of the second intermediate pulley 352 is transmitted to the wave generator 323 of the second reducer 32 via the third belt 353 and the second reducer-side pulley 351, causing the wave generator 323 to rotate around the third rotation axis J3. Furthermore, the flexspline 322 rotates at a predetermined reduction ratio with respect to the rotation of the wave generator 323, causing the third arm 123 to rotate around the third rotation axis J3 relative to the second arm 122.

[0035] The second power transmission mechanism 33 has the first transmission mechanism 34, which increases the degree of freedom in arranging the second motor 31. In particular, the output shaft 311 of the second motor 31 can be arranged offset from the second rotation axis J2, which effectively prevents the through hole H1 of the first reducer 22 from overlapping with the second motor 31. This makes it easy to insert the shaft 36 and the wiring L into the through hole H1.

[0036] Furthermore, in the second power transmission mechanism 33, the first transmission mechanism 34 can be used as a reducer by adjusting the diameters of the second motor-side pulley 341 and the first intermediate pulley 342. Similarly, the second transmission mechanism 35 can be used as a reducer by adjusting the diameters of the second reducer-side pulley 351 and the second intermediate pulley 352. In this way, a larger reduction ratio can be achieved by using two reducers formed by the first and second transmission mechanisms 34 and 35 and the second reducer 32. Furthermore, by configuring the first and second transmission mechanisms 34 and 35 using two pulleys and a belt, these can be formed from lightweight materials such as resin and rubber, thereby reducing the weight of the second power transmission mechanism 33.

[0037] However, the second power transmission mechanism 33 is not particularly limited. For example, the first transmission mechanism 34 may be configured such that the second motor-side pulley 341 and the first intermediate pulley 342 are each replaced with gears, and the second belt 343 is replaced with a chain that meshes with these two gears. Alternatively, the chain may be omitted, and the gears may mesh directly with each other. Similarly, the second transmission mechanism 35 may be configured such that the second reducer-side pulley 351 and the second intermediate pulley 352 are each replaced with gears, and the third belt 353 is replaced with a chain that meshes with these two gears. Alternatively, the chain may be omitted, and the gears may mesh directly with each other. However, compared to such a configuration using gears and chains, the configuration using pulleys and belts as in this embodiment can reduce backlash in the second power transmission mechanism 33 and enable more accurate control of the third arm 123. Alternatively, the first transmission mechanism 34 may be omitted, and the second motor 31 may be directly connected to the shaft 36. In this case, the shaft 36 and the output shaft 311 may be integrally formed.

[0038] As shown in FIG. 3 , in this embodiment, the shaft 36 is a hollow shaft, and a through-hole 361 is formed therein, which connects the first arm 121 with the second arm 122. The wiring L is routed from the first arm 121 to the second arm 122 through the through-hole 361. This configuration makes it easy to route the wiring L from the first arm 121 to the second arm 122. Furthermore, as shown in FIG. 5 , the wiring L routed to the second arm 122 passes through the through-hole H2 of the second reducer 32 and is routed to the third arm 123 beyond. This configuration makes it easy to route the wiring L from the second arm 122 to the third arm 123.

[0039] As described above, in the vertical articulated robot 1, the first motor 21 provided in the second drive unit 132 and the second motor 31 provided in the third drive unit 133 are both disposed inside the first arm 121 located at the base end of the robot arm 12. By disposing the first and second motors 21, 31, which are heavy objects, inside the first arm 121 in this way, the weight of the tip end of the robot arm 12 can be reduced, and the moment of inertia of the robot arm 12 can be reduced accordingly. This allows the robot arm 12 to be controlled with high precision.

[0040] In particular, in this embodiment, only the second transmission mechanism 35 (including components related to the second transmission mechanism 35, such as bearing members) and the wiring L (including components attached to the wiring L, such as tie wraps for bundling the wiring L) are arranged within the second arm 122. In other words, no components other than the second transmission mechanism 35 and the wiring L are arranged within the second arm 122. This makes the second arm 122 lighter, thereby further reducing the moment of inertia of the robot arm 12. Furthermore, by reducing the number of components arranged in the second arm 122, the second arm 122 can be made shorter, thereby further reducing the moment of inertia of the robot arm 12. Note that the drive units 134, 135, and 136 of the fourth, fifth, and sixth arms 124, 125, and 126 at the tip side may be arranged in the second arm 122 of this embodiment. This reduces the weight of the tip of the robot arm 12.

[0041] In this embodiment, as shown in FIGS. 3 and 6 , the first motor 21 and the second motor 31 overlap each other in a horizontal direction perpendicular to the second rotation axis J2, i.e., in a plan view from the X-axis direction. In other words, the first motor 21 and the second motor 31 are arranged side by side in the horizontal direction. Note that the phrase "the first motor 21 and the second motor 31 overlap each other in a plan view from the horizontal direction perpendicular to the second rotation axis J2" means that at least a portion of the first motor 21 and the second motor 31 overlap each other in a plan view from the X-axis direction. This configuration allows the first motor 21 and the second motor 31 to be positioned as close as possible to the lower end of the first arm 121, thereby lowering the center of gravity of the robot arm 12. This further reduces the moment of inertia of the robot arm 12. Furthermore, in this embodiment, the output shafts 211 and 311 of the first motor 21 and the second motor 31 are located below the second rotation axis J2. Therefore, the center of gravity of the robot arm 12 is further lowered, and the above-mentioned effects become more pronounced.

[0042] In this embodiment, as shown in FIGS. 3 and 6 , the second rotation axis J2 is located between the first motor 21 and the second motor 31 in a vertical plan view. That is, the first motor 21 is located on one side of the second rotation axis J2 in the horizontal direction, and the second motor 31 is located on the other side. Alternatively, the first rotation axis J1 may be located between the first motor 21 and the second motor 31 in a vertical plan view. That is, the first motor 21 may be located on one side of the first rotation axis J1 in the horizontal direction, and the second motor 31 may be located on the other side. This configuration effectively prevents the center of gravity of the first arm 121 from shifting relative to the first rotation axis J1. This allows the first arm 121 to rotate about the first rotation axis J1 more smoothly and accurately.

[0043] In this embodiment, the first and second motors 21, 31 are arranged inside the first arm 121, but this is not limiting, and at least one of the first and second motors 21, 31 may be arranged outside the first arm 121. In other words, at least one of the first and second motors 21, 31 may be exposed to the outside of the vertical articulated robot 1.

[0044] The above has described the vertical articulated robot 1. As described above, the vertical articulated robot 1 has the base 11, the first arm 121 that rotates around the first rotation axis J1 that is a vertical axis relative to the base 11, the second arm 122 that is connected to the first arm 121 and rotates around the second rotation axis J2 that is a first horizontal axis relative to the first arm 121, the third arm 123 that is connected to the second arm 122 and rotates around the third rotation axis J3 that is a second horizontal axis relative to the second arm 122, the first motor 21 that rotates the second arm 122 around the second rotation axis J2 relative to the first arm 121, and the second motor 31 that rotates the third arm 123 around the third rotation axis J3 relative to the second arm 122, and the first motor 21 and the second motor 31 are each disposed on the first arm 121. In this way, by arranging the first and second motors 21, 31, which are heavy objects, on the first arm 121, it is possible to reduce the weight of the tip of the robot arm 12, and accordingly reduce the moment of inertia of the robot arm 12. As a result, it is possible to control the robot arm 12 with high precision.

[0045] As described above, the vertical articulated robot 1 also has the first reducer 22 that connects the first arm 121 and the second arm 122, and the first power transmission mechanism 23 that connects the first motor 21 and the first reducer 22 and transmits the power of the first motor 21 to the first reducer 22. This configuration increases the degree of freedom in arranging the first motor 21.

[0046] As described above, the first power transmission mechanism 23 includes the first motor-side pulley 231 disposed on the output shaft 211 of the first motor 21, the first reducer-side pulley 232 disposed on the wave generator 223, which is the input shaft of the first reducer 22, and the first belt 233 wound around the first motor-side pulley 231 and the first reducer-side pulley 232. This configuration simplifies the configuration of the first power transmission mechanism 23. Furthermore, by adjusting the diameters of the first motor-side pulley 231 and the first reducer-side pulley 232, the first power transmission mechanism 23 can also be used as a reducer. Therefore, a larger reduction ratio can be achieved by using the first power transmission mechanism 23 and the first reducer 22. Furthermore, backlash in the first power transmission mechanism 23 can be reduced, enabling precise control of the second arm 122.

[0047] As described above, the vertical articulated robot 1 also has the second reducer 32 that connects the second arm 122 and the third arm 123, and the second power transmission mechanism 33 that connects the second motor 31 and the second reducer 32 and transmits the power of the second motor 31 to the second reducer 32. This configuration increases the degree of freedom in arranging the second motor 31.

[0048] As described above, the second power transmission mechanism 33 includes a first transmission mechanism 34 disposed within the first arm 121 and a second transmission mechanism 35 disposed within the second arm 122. The first transmission mechanism 34 includes a second motor-side pulley 341 disposed on the output shaft 311 of the second motor 31, a first intermediate pulley 342 that rotates about the second rotation axis J2, and a second belt 343 that is wound around the second motor-side pulley 341 and the first intermediate pulley 342. The second transmission mechanism 35 includes a second intermediate pulley 352 that rotates about the second rotation axis J2 together with the first intermediate pulley 342, a second reducer-side pulley 351 disposed on the wave generator 323 that is the input shaft of the second reducer 32, and a third belt 353 that is wound around the second intermediate pulley 352 and the second reducer-side pulley 351. This configuration simplifies the configuration of the second power transmission mechanism 33. Furthermore, by adjusting the diameters of the second motor-side pulley 341 and the first intermediate pulley 342, the first transmission mechanism 34 can be used as a reducer, and by adjusting the diameters of the second reducer-side pulley 351 and the second intermediate pulley 352, the second transmission mechanism 35 can be used as a reducer. Therefore, a larger reduction ratio can be achieved by using the first and second transmission mechanisms 34, 35 and the second reducer 32. Furthermore, backlash in the second power transmission mechanism 33 can be reduced, allowing the third arm 123 to be controlled with high precision.

[0049] As described above, the first reducer 22 is provided with a through hole H1 along the second rotation axis J2, which connects the inside of the first arm 121 with the inside of the second arm 122. The first intermediate pulley 342 and the second intermediate pulley 352 are connected via the shaft 36 that is inserted through the through hole H1. With this configuration, the first intermediate pulley 342 and the second intermediate pulley 352 can be connected with a simple structure and rotated integrally around the second rotation axis J2.

[0050] As described above, the shaft 36 is a hollow shaft, and the wire L is routed between the first arm 121 and the second arm 122 through the inside of the shaft 36. With this configuration, the wire L can be easily routed.

[0051] As described above, the second arm 122 is connected to the first arm 121 from one side in the direction along the second rotation axis J2. In other words, the second arm 122 is cantilevered by the first arm 121. This configuration allows the weight of the second arm 122 to be reduced. As a result, the weight of the entire robot arm 12 can be reduced, and the moment of inertia of the robot arm 12 can be reduced accordingly.

[0052] As described above, the first motor 21 and the second motor 31 overlap each other in a plan view from a horizontal direction perpendicular to the second rotation axis J2. With this configuration, both the first motor 21 and the second motor 31 can be disposed closer to the lower end of the first arm 121, lowering the center of gravity of the robot arm 12. This allows the moment of inertia of the robot arm 12 to be further reduced.

[0053] Furthermore, as described above, in a plan view from the vertical direction, the second rotation axis J2 is located between the first motor 21 and the second motor 31. With this configuration, it is possible to effectively suppress deviation of the center of gravity of the first arm 121 with respect to the first rotation axis J1. Therefore, it is possible to more smoothly and accurately rotate the first arm 121 about the first rotation axis J1.

[0054] Second Embodiment Fig. 7 is a cross-sectional view showing a vertical articulated robot according to the second embodiment, Fig. 8 is a side view showing the arrangement of the first motor and the second motor.

[0055] This embodiment is similar to the first embodiment described above, except that the first and second motors 21, 31 are arranged differently within the first arm 121. In the following description, differences between this embodiment and the first embodiment will be mainly described, and similar points will not be described again. In addition, in each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above embodiment.

[0056] As shown in FIGS. 7 and 8 , in the vertically articulated robot 1 of this embodiment, the first motor 21 and the second motor 31 overlap each other in the vertical direction, i.e., in a plan view from the Z-axis direction. In other words, the first motor 21 and the second motor 31 are arranged side by side in the vertical direction. Note that the phrase "the first motor 21 and the second motor 31 overlap each other in a plan view from the vertical direction" means that at least a portion of the first motor 21 and the second motor 31 overlap each other in a plan view from the Z-axis direction. This configuration can suppress the horizontal expansion of the first arm 121, thereby enabling the first arm 121 to be made smaller. This reduces the weight of the first arm 121, further reducing the moment of inertia of the robot arm 12.

[0057] In the present embodiment, the first motor 21 is positioned above the second motor 31, but this is not limiting, and for example, the first motor 21 may be positioned below the second motor 31. Furthermore, in the present embodiment, the first motor 21 is positioned above the second rotation axis J2, and the second motor 31 is positioned below the second rotation axis J2, but this is not limiting, and for example, the first motor 21 may be positioned below the second rotation axis J2, and the second motor 31 may be positioned above the second rotation axis J2, or both the first and second motors 21, 31 may be positioned above the second rotation axis J2, or both the first and second motors 21, 31 may be positioned below the second rotation axis J2.

[0058] As described above, in the vertically articulated robot 1 of this embodiment, the first motor 21 and the second motor 31 overlap each other in a plan view from the vertical direction. With this configuration, the horizontal spread of the first arm 121 can be suppressed, and the first arm 121 can be made smaller. Therefore, the weight of the first arm 121 can be reduced, and the moment of inertia of the robot arm 12 can be further reduced.

[0059] The second embodiment can also achieve the same effects as the first embodiment described above.

[0060] <Third embodiment> FIG. 9 is a cross-sectional view showing a vertical articulated robot according to the third embodiment.

[0061] This embodiment is similar to the first embodiment described above, except for the configurations of the second arm 122, the second drive unit 132, and the third drive unit 133. In the following description, the differences between this embodiment and the first embodiment will be mainly described, and a description of similar points will be omitted. In the drawings of this embodiment, the same reference numerals are used to designate similar components to those in the previously described embodiment.

[0062] 9, in the vertical articulated robot 1 of this embodiment, the second arm 122 is connected to the first arm 121 from both sides in the direction along the second rotation axis J2. In other words, the second arm 122 is supported at both ends by the first arm 121. With this configuration, for example, the rigidity of the second arm 122 is increased compared to the first embodiment described above. Therefore, vibration of the second arm 122 can be effectively suppressed.

[0063] At a connecting portion on one side in the direction along the second rotation axis J2, the first arm 121 and the second arm 122 are connected via a first reducer 22, as in the first embodiment described above. On the other hand, at a connecting portion on the other side in the direction along the second rotation axis J2, the first arm 121 and the second arm 122 are connected via a bearing. A communication hole 5 is formed in this portion along the second rotation axis J2, connecting the inside of the first arm 121 with the inside of the second arm 122. The communication hole 5 is formed by overlapping a first communication hole 51 formed in the first arm 121 and a second communication hole 52 formed in the second arm 122. A shaft 36 connecting the first intermediate pulley 342 and the second intermediate pulley 352 is inserted through the communication hole 5. Furthermore, a wire L is routed from the first arm 121 to the second arm 122 through the inside of the shaft 36 .

[0064] In this embodiment, there is no need to insert the shaft 36 or the wiring L into the first reducer 22. Therefore, the wave generator 223 of the first reducer 22 has a solid structure. By making the wave generator 223 a solid structure in this way, the rigidity of the first reducer 22 can be increased compared to the first embodiment described above. Therefore, vibration of the second arm 122 can be effectively suppressed. Furthermore, compared to the first embodiment described above, the first reducer 22 can be made smaller and lighter, and accordingly, the robot arm 12 can be made smaller and lighter. Therefore, the moment of inertia of the robot arm 12 can be reduced.

[0065] As described above, in the vertical articulated robot 1 of this embodiment, the second arm 122 is connected to the first arm 121 from both sides in the direction along the second rotation axis J2. With this configuration, the rigidity of the second arm 122 can be increased. Furthermore, the shaft 36 connecting the first intermediate pulley 342 and the second intermediate pulley 352 can be disposed in a connecting portion separate from the first reducer 22. Therefore, the wave generator 223 has a solid structure, and the rigidity of the first reducer 22 can be increased. Therefore, vibration of the second arm 122 can be effectively suppressed.

[0066] The third embodiment can also achieve the same effects as the first embodiment described above.

[0067] <Fourth embodiment> FIG. 10 is a cross-sectional view showing a vertical articulated robot according to the fourth embodiment.

[0068] This embodiment is similar to the first embodiment described above, except that the third motor 41 provided in the first drive unit 131 is disposed inside the first arm 121. In the following description, differences between this embodiment and the first embodiment will be mainly described, and descriptions of similar points will be omitted. In addition, in the drawings of this embodiment, the same reference numerals are used to designate the same components as those in the previously described embodiment.

[0069] 10, in the vertical articulated robot 1 of this embodiment, a third motor 41 provided in a first drive unit 131 that rotates the first arm 121 about a first rotation axis J1 relative to the base 11 is disposed within the first arm 121. Although not specifically explained, in the first embodiment described above, the third motor 41 is disposed within the base 11. In contrast, by disposing the third motor 41 within the first arm 121 as in this embodiment, the base 11 can be made smaller. As a result, the installation area of ​​the vertical articulated robot 1 can be reduced.

[0070] Like the second drive unit 132, the first drive unit 131 has a third motor 41 which is a motor with a built-in encoder, a third reducer 42 which connects the base 11 and the first arm 121, and a third power transmission mechanism 43 which connects the third motor 41 and the third reducer 42 and transmits the power of the third motor 41 to the third reducer 42.

[0071] The third motor 41, like the first motor 21, is a servo motor, in particular a three-phase motor driven by three-phase AC. Similarly to the first reduction gear 22, the third reduction gear 42 is a wave gear device and is mainly composed of a circular spline 421, a flexspline 422, and a wave generator 423. Similarly to the first power transmission mechanism 23, the third power transmission mechanism 43 has a third motor-side pulley 431 attached to the output shaft 411 of the third motor 41, a third reduction gear-side pulley 432 attached to the wave generator 423 which is the input shaft of the third reduction gear 42, and a fourth belt 433 passed around the third motor-side pulley 431 and the third reduction gear-side pulley 432.

[0072] The fourth embodiment as described above can also achieve the same effects as the first embodiment.

[0073] While the vertical articulated robot of the present invention has been described above based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other configuration may be added to the present invention. Furthermore, the above-described embodiments may be combined as appropriate. [Explanation of symbols]

[0074] 1...vertical articulated robot, 11...base, 12...robot arm, 121...first arm, 122...second arm, 123...third arm, 124...fourth arm, 125...fifth arm, 126...sixth arm, 131...first drive unit, 132...second drive unit, 133...third drive unit, 134...fourth drive unit, 135...fifth drive unit, 136...sixth drive unit, 14...control board, 15...power supply Circuit board, 21...first motor, 211...output shaft, 22...first reducer, 221...circular spline, 222...flexspline, 223...wave generator, 23...first power transmission mechanism, 231...first motor side pulley, 232...first reducer side pulley, 233...first belt, 31...second motor, 311...output shaft, 32...second reducer, 321...circular spline, 322...flexspline , 323...wave generator, 33...second power transmission mechanism, 34...first transmission mechanism, 341...second motor side pulley, 342...first intermediate pulley, 343...second belt, 35...second transmission mechanism, 351...second reducer side pulley, 352...second intermediate pulley, 353...third belt, 36...shaft, 361...through hole, 41...third motor, 411...output shaft, 42...third reducer, 421...circular pulley In, 422... flexspline, 423... wave generator, 43... third power transmission mechanism, 431... third motor side pulley, 432... third reducer side pulley, 433... fourth belt, 5... communication hole, 51... first communication hole, 52... second communication hole, H1... through hole, H2... through hole, J1... first rotating shaft, J2... second rotating shaft, J3... third rotating shaft, J4... fourth rotating shaft, J5... fifth rotating shaft, J6... sixth rotating shaft, L... wiring

Claims

1. The base and a first arm that rotates about a vertical axis relative to the base; a second arm connected to the first arm and rotatable relative to the first arm about a first horizontal axis; a third arm connected to the second arm and rotatable about a second horizontal axis relative to the second arm; a first motor that rotates the second arm relative to the first arm about the first horizontal axis; a second motor that rotates the third arm about the second horizontal axis relative to the second arm, A vertical articulated robot, characterized in that the first motor and the second motor are each arranged on the first arm.

2. a first reducer connecting the first arm and the second arm; 2. The vertical articulated robot according to claim 1, further comprising: a first power transmission mechanism that connects the first motor and the first reducer and transmits the power of the first motor to the first reducer.

3. The first power transmission mechanism includes: a first motor side pulley disposed on an output shaft of the first motor; a first reducer side pulley disposed on an input shaft of the first reducer; 3. The vertical articulated robot according to claim 2, further comprising: a first belt that is wound around the first motor-side pulley and the first reducer-side pulley.

4. a second reducer connecting the second arm and the third arm; 4. The vertical articulated robot according to claim 3, further comprising: a second power transmission mechanism that connects the second motor and the second reducer and transmits the power of the second motor to the second reducer.

5. The second power transmission mechanism is a first transmission mechanism disposed in the first arm and a second transmission mechanism disposed in the second arm, The first transmission mechanism includes: a second motor side pulley disposed on an output shaft of the second motor; a first intermediate pulley that rotates about the first horizontal axis; a second belt that is wound around the second motor-side pulley and the first intermediate pulley, The second transmission mechanism includes: a second intermediate pulley that rotates together with the first intermediate pulley about the first horizontal axis; a second reducer side pulley disposed on an input shaft of the second reducer; 5. The vertical articulated robot according to claim 4, further comprising a third belt that is wound around the second intermediate pulley and the second reducer-side pulley.

6. the first reducer is provided with a through hole along the first horizontal axis, the through hole communicating the first arm with the second arm; The vertical articulated robot according to claim 5 , wherein the first intermediate pulley and the second intermediate pulley are connected via a shaft inserted through the through hole.

7. the shaft is a hollow shaft, 7. The vertical articulated robot according to claim 6, wherein wiring is routed between the first arm and the second arm through the inside of the shaft.

8. 2. The vertical articulated robot according to claim 1, wherein the second arm is connected to the first arm from one side in a direction along the first horizontal axis.

9. The vertical articulated robot according to claim 1 , wherein the second arm is connected to the first arm from both sides in a direction along the first horizontal axis.

10. The vertical articulated robot according to claim 1 , wherein the first motor and the second motor overlap each other in a plan view from a horizontal direction perpendicular to the first horizontal axis.

11. The vertical articulated robot according to claim 10 , wherein the first horizontal shaft is located between the first motor and the second motor in a plan view from the vertical direction.

12. The vertically articulated robot according to claim 1 , wherein the first motor and the second motor overlap each other in a plan view from the vertical direction.

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