robot

Abstract

To provide a robot which is excellent in damping performance.SOLUTION: A robot includes: a base; a first arm which rotates around a first axis; a second arm which rotates around a second axis parallel to the first axis; a first shaft which moves in an axial direction of a third axis parallel to the second axis and rotates around the third axis; a first motor which is provided at the second arm and driven so as to move the first shaft in the axial direction of the third axis; a second motor which is provided at the second arm and driven so as to rotate the first shaft around the third axis; a second shaft which is arranged along a fourth axis, which is different from the third axis and parallel to the third axis, and transmits a driving force of the first motor to the first shaft through a connection member; and a pulley which is disposed so that its rotation center overlaps with a central axis of the second shaft and transmits a driving force from the second motor to the first shaft. The second shaft overlaps with a straight line connecting the second axis with the third axis when viewed from an axial direction of the fourth axis.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a robot.

Background Art

[0002] In recent years, in factories, due to the soaring labor costs and the shortage of human resources, the automation of operations that have been carried out manually has been accelerating by various robots and their peripheral devices. Examples of such various robots include scalar robots as described in Patent Document 1.

[0003] The scalar robot described in Patent Document 1 includes a base, a first arm connected to the base, a second arm connected to the first arm, a work axis that is connected to the second arm and moves up and down and rotates, and a work axis lifting mechanism that lifts the work axis.

[0004] Further, the work axis lifting mechanism includes a lifting belt that transmits the driving force of a work axis lifting motor via a drive pulley and a driven pulley, a vertical movement bracket that rotatably holds the work axis in a state of being fixed to the lifting belt and moves up and down integrally with the work axis as the lifting belt is conveyed, and a guide shaft that guides the up and down movement of the vertical movement bracket. The work axis and the guide shaft are arranged offset from the center in the longitudinal direction of the second arm.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the scalar robot described in Patent Document 1, the weight balance cannot be achieved on both sides via the central axis, and excessive vibration may occur when the robot arm is driven. [Means for solving the problem]

[0007] This invention was made to solve at least some of the aforementioned problems and can be realized as follows.

[0008] The robot of the present invention comprises a base and A first arm connected to the base and rotating around a first axis, A second arm connected to the first arm and rotating around a second axis parallel to the first axis, A first shaft is connected to the second arm and moves in the axial direction of a third axis parallel to the second axis, and rotates around the third axis, A first motor is provided on the second arm and drives the first shaft to move in the axial direction of the third axis, A second motor is provided on the second arm and drives the first shaft to rotate around the third axis, A second shaft is arranged along a fourth axis that is different from the third axis and parallel to the third axis, and transmits the driving force of the first motor to the first shaft via a connecting member, The system includes a pulley whose center of rotation is positioned to coincide with the central axis of the second shaft, and which transmits the driving force from the second motor to the first shaft, The second shaft is characterized in that, when viewed from the axial direction of the fourth axis, it coincides with the straight line connecting the second axis and the third axis. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view showing a first embodiment of the robot of the present invention. [Figure 2] Figure 1 is a block diagram of the robot system shown. [Figure 3] This is a partial cross-sectional view showing the inside of the second arm of the robot arm shown in Figure 1. [Figure 4]This is a schematic plan view showing the interior of the second arm of the robot arm shown in Figure 1. [Figure 5] This is a schematic plan view showing the interior of the second arm of a second embodiment of the robot of the present invention. [Figure 6] This is a schematic plan view showing the interior of the second arm of a third embodiment of the robot of the present invention. [Figure 7] This is a partial cross-sectional view showing the inside of the second arm of a fourth embodiment of the robot of the present invention. [Modes for carrying out the invention]

[0010] The robot of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. <First Embodiment> Figure 1 is a side view showing a first embodiment of the robot of the present invention. Figure 2 is a block diagram of the robot system shown in Figure 1. Figure 3 is a partial cross-sectional view showing the interior of the second arm of the robot arm shown in Figure 1. Figure 4 is a schematic plan view showing the interior of the second arm of the robot arm shown in Figure 1.

[0011] Furthermore, in Figures 1, 3, and 4 (and similarly in Figures 5 and 6), for the sake of explanation, the x, y, and z axes are depicted as three mutually orthogonal axes. In the following, the direction parallel to the x-axis will also be referred to as the "x-axis direction," the direction parallel to the y-axis as the "y-axis direction," and the direction parallel to the z-axis as the "z-axis direction." In the following, the tip of each arrow shown will be referred to as "+ (plus)" and the base as "- (minus)." The direction parallel to the +x-axis direction will also be referred to as the "+x-axis direction," the direction parallel to the -x-axis direction as the "-x-axis direction," the direction parallel to the +y-axis direction as the "+y-axis direction," the direction parallel to the -y-axis direction as the "-y-axis direction," the direction parallel to the +z-axis direction as the "+z-axis direction," and the direction parallel to the -z-axis direction as the "-z-axis direction." In addition, the direction around the z-axis and the direction around the axis parallel to the z-axis will also be referred to as the "u-axis direction."

[0012] In the following, for the sake of convenience of explanation, the +z-axis direction in FIG. 1, that is, the upper side, is also referred to as "up" or "above", and the -z-axis direction, that is, the lower side, is also referred to as "down" or "below". Regarding the robot arm 20, the base 21 side in FIG. 1 is referred to as the "base end", and the opposite side, that is, the end effector 7 side, is referred to as the "tip". Also, the z-axis direction in FIG. 1, that is, the vertical direction, is referred to as the "vertical direction", and the x-axis direction and the y-axis direction, that is, the horizontal direction, are referred to as the "horizontal direction".

[0013] The robot system 100 shown in FIGS. 1 and 2 is a device used, for example, in operations such as holding, transporting, assembling, and inspecting workpieces such as electronic components and electronic devices. The robot system 100 includes a control device 1, a robot 2, and an end effector 7.

[0014] Also, the control device 1 is arranged at a position different from the robot 2, that is, outside the robot 2. In the illustrated configuration, the robot 2 and the control device 1 are electrically connected (hereinafter, also simply referred to as "connected") by a cable 200, but it is not limited to this, and the cable 200 may be omitted and communication may be performed by a wireless method. That is, the robot 2 and the control device 1 may be connected by wired communication or may be connected by wireless communication.

[0015] In the illustrated configuration, the robot 2 is a horizontal articulated robot, that is, a scalar robot.

[0016] As shown in FIG. 1, the robot 2 includes a base 21, a first arm 22, a second arm 23, a third arm 24 which is a work head, and a force detection unit 5. The robot arm 20 is constituted by the first arm 22, the second arm 23, and the third arm 24.

[0017] Further, the robot 2 includes a drive unit 25 that rotates the first arm 22 with respect to the base 21, a drive unit 26 that rotates the second arm 23 with respect to the first arm 22, a u drive unit 27 that rotates the tip shaft (first shaft) 241 of the third arm 24 with respect to the second arm 23, and a z drive unit 28 that moves the tip shaft 241 in the z-axis direction with respect to the second arm 23.

[0018] As shown in FIGS. 1 and 2, the drive unit 25 is built into the base 21 and includes a motor 251 that generates a driving force, a speed reducer 252 that reduces the rotational speed of the motor 251, that is, reduces the driving force, and a position sensor 253 that detects the rotational angle of the rotating shaft of the motor 251 or the speed reducer 252.

[0019] The drive unit 26 is built into the housing 230 of the second arm 23 and includes a motor 261 that generates a driving force, a speed reducer 262 that reduces the driving force of the motor 261, and a position sensor 263 that detects the rotational angle of the rotating shaft of the motor 261 or the speed reducer 262.

[0020] The u drive unit 27 is built into the housing 230 of the second arm 23 and includes a motor 271 that generates a driving force and a position sensor 273 that detects the rotational angle of the rotating shaft of the motor 271.

[0021] The z drive unit 28 is built into the housing 230 of the second arm 23 and includes a motor 281 that generates a driving force and a position sensor 283 that detects the rotational angle of the rotating shaft of the motor 281.

[0022] As the motors 251, 261, 271, and 281, for example, servo motors such as AC servo motors and DC servo motors can be used.

[0023] Furthermore, for the reduction gears 252 and 262, for example, planetary gear type reduction gears, harmonic drive gears, etc., can be used. Also, the position sensors 253, 263, 273, and 283 can be, for example, angle sensors.

[0024] The drive units 25, 26, u-drive unit 27, and z-drive unit 28 are each connected to corresponding motor drivers (not shown) and are controlled by the robot control unit 11 of the control device 1 via the motor drivers.

[0025] The base 21 is fixed to a floor surface (not shown) by bolts or the like. The first arm 22 is connected to the upper end of the base 21. The first arm 22 is rotatable around a first axis O1 that is perpendicular to the base 21. When the drive unit 25 that rotates the first arm 22 is driven, the first arm 22 rotates in the horizontal plane around the first axis O1 relative to the base 21. In addition, the amount of rotation of the first arm 22 relative to the base 21 can be detected by the position sensor 253.

[0026] Furthermore, a second arm 23 is connected to the tip of the first arm 22. The second arm 23 is rotatable around a second axis O2 that is perpendicular to the first arm 22. The axial direction of the first axis O1 and the axial direction of the second axis O2 are the same. That is, the second axis O2 is parallel to the first axis O1. When the drive unit 26 that rotates the second arm 23 is driven, the second arm 23 rotates in the horizontal plane around the second axis O2 relative to the first arm 22. In addition, the position sensor 263 can detect the drive of the second arm 23 relative to the first arm 22, specifically the amount of rotation. That is, the second axis O2 is the center of the output rotation axis of the reduction gear 262.

[0027] Furthermore, the second arm 23 has a housing 230 having a base portion 231 which is a wall portion, a top plate 232, and four side walls 233 which connect them. Inside this housing 230, that is, on the base portion 231, the drive unit 26, the u drive unit 27, and the z drive unit 28 are arranged in this order from the +y axis side.

[0028] Furthermore, as shown in Figure 3, the base portion 231 is the bottom of the second arm 23. The base portion 231 also has recesses, although not shown, where the u-drive unit 27 and the z-drive unit 28 are located.

[0029] Furthermore, a third arm 24 is installed at the tip of the second arm 23. The third arm 24 has a tip shaft 241.

[0030] The tip shaft 241 is rotatable around a third axis O3 that is perpendicular to the second arm 23, and is also movable (up and down) in the vertical direction. In this embodiment, the tip shaft 241 is a ball spline axis and is the furthest arm of the robot arm 20.

[0031] Furthermore, various end effectors are detachably connected to the tip of the tip shaft 241. The end effectors are not particularly limited and include, for example, those for gripping objects to be conveyed, for processing objects, and for inspection. In this embodiment, an end effector 7 is detachably connected.

[0032] In this embodiment, the end effector 7 is not a component of the robot 2, but part or all of the end effector 7 may be a component of the robot 2. Also, in this embodiment, the end effector 7 is not a component of the robot arm 20, but part or all of the end effector 7 may be a component of the robot arm 20.

[0033] Furthermore, in this embodiment, the end effector 7 is detachable from the robot arm 20, but this is not limited to this, and for example, the end effector 7 may be made indestructible from the robot arm 20.

[0034] As shown in Figure 2, the control device 1 comprises a robot control unit 11, a motor control unit 12 (end effector control unit), a display control unit 13, a storage unit 14, and a reception unit 15, and controls the drive of each part of the robot system 100, such as the robot 2 and the motor 72 of the end effector 7.

[0035] Furthermore, the control device 1 is configured to communicate with each other: the robot control unit 11, the motor control unit 12, the display control unit 13, the storage unit 14, and the reception unit 15. In other words, the robot control unit 11, the motor control unit 12, the display control unit 13, the storage unit 14, and the reception unit 15 are connected to each other by wired or wireless communication.

[0036] Furthermore, the control device 1 is connected to the robot 2 and the end effector 7, respectively, by wired or wireless communication.

[0037] The robot control unit 11 controls the driving of the robot 2, that is, the driving of the robot arm 20, etc. The robot control unit 11 is a computer on which programs such as an OS are installed. This robot control unit 11 has, for example, a CPU as a processor, RAM and ROM where programs are stored. Furthermore, the functions of the robot control unit 11 can be realized, for example, by executing various programs using the CPU.

[0038] The motor control unit 12 controls the drive of the motor 72. The motor control unit 12 is a computer on which programs such as an OS are installed. This motor control unit 12 has, for example, a CPU as a processor, RAM and ROM where programs are stored. Furthermore, the functions of the motor control unit 12 can be realized, for example, by executing various programs using the CPU.

[0039] The display control unit 13 has the function of displaying various screens such as windows and characters on a display device (not shown).

[0040] The memory unit 14 has the function of storing various types of information (including data and programs). This memory unit 14 stores control programs and the like. The functions of the memory unit 14 can be realized by a so-called external storage device (not shown), such as a ROM. The reception unit 15 has the function of receiving input from an input device (not shown).

[0041] Next, we will describe the interior of the second arm 23. As shown in Figure 3, the housing 230 of the second arm 23 is provided with a u-drive unit 27 for rotating the third arm 24 around the third axis O3, a z-drive unit 28 for moving the third arm 24 in the z-axis direction, and a transmission shaft (second shaft) 29.

[0042] As shown in Figure 3, the u-drive unit 27 has the aforementioned motor 271 and position sensor 273. The u-drive unit 27 is fixed to the bottom of the base portion 231, although this is not shown in the figure.

[0043] The z-drive unit 28 also includes the aforementioned motor 281 and position sensor 283. Although not shown in the figures, the z-drive unit 28 is fixed to the bottom of the base portion 231.

[0044] Furthermore, the -z-axis end of the tip shaft 241 is rotatably supported by the base portion 231. A spline nut 245 and a pulley 242 are also provided at the -z-axis end of the tip shaft 241. A belt 243 is wrapped around the pulley 242. The belt 243 is wrapped around the pulley 242 and a connecting member pulley 291.

[0045] Furthermore, a connecting member 244 is fixed to the +z-axis end of the tip shaft 241 via a bearing 247. The connecting member 244 is a member that connects the tip shaft 241 and the transmission shaft 29. The connecting member 244 is fixed to the transmission shaft 29 via a ball screw nut 246. The ball screw nut 246 is provided at the +z-axis end of the transmission shaft 29 and is attached to the aforementioned connecting member 244 in a manner that prevents rotation.

[0046] The transmission shaft 29 is positioned on the +y axis side of the tip shaft 241 and extends along the fourth axis O4, which is parallel to the third axis O3. The transmission shaft 29 is rotatably supported by the base portion 231.

[0047] A pulley 291, which is a relay member, is provided at the -z-axis end of the transmission shaft 29. The pulley 291 has an insertion hole 290 and has a large diameter portion 292 and a small diameter portion 293. A belt 274 is wrapped around the large diameter portion 292, and a belt 243 is wrapped around the small diameter portion 293. The belt 274 is wrapped around the output shaft of the u-drive unit 27.

[0048] The pulley 291 is rotatably fixed to the base portion 231, and is positioned so that its center of rotation coincides with the central axis of the transmission shaft 29. The transmission shaft 29 can rotate within the insertion hole 290 of the pulley 291 without interference. In other words, the transmission shaft 29 and the pulley 291 can rotate independently of each other around the fourth axis O4.

[0049] Furthermore, a belt 284 is wrapped around the -z-axis end of the transmission shaft 29 and the +z-axis side of the pulley 291. The belt 284 is wrapped around the output shaft of the z-drive unit 28.

[0050] The driving force of the motor 271 is transmitted to the tip shaft 241 via belt 274, pulley 291, belt 243, and pulley 242. As a result, the tip shaft 241 rotates in both forward and reverse directions around the z-axis. In addition, the position sensor 273 allows the amount of rotation of the tip shaft 241 relative to the second arm 23 to be detected.

[0051] The driving force of the motor 281 is transmitted to the tip shaft 241 via the belt 284, transmission shaft 29, ball screw nut 246, connecting member 244, and bearing 247. As a result, the ball screw nut 246, connecting member 244, bearing 247, and tip shaft 241 move up and down together in the z-axis direction. In addition, the position sensor 283 can detect the amount of z-axis movement of the tip shaft 241 relative to the second arm 23.

[0052] Next, the positional relationship between the transmission shaft 29, the second axis O2, and the third axis O3 will be explained. Conventionally, the component corresponding to the transmission shaft 29 was positioned at a location offset from the straight line connecting the axis corresponding to the second axis O2 and the axis corresponding to the third axis O3, when viewed in the axial direction of the z-axis. As a result, the weight balance is not maintained on both sides of the straight line connecting the axis corresponding to the second axis O2 and the axis corresponding to the third axis O3, which may cause excessive vibration when the robot arm is driven.

[0053] In contrast, the present invention can solve the above problems by adopting the following configuration. As shown in Figure 4, in the robot 2, the transmission shaft 29 coincides with the straight line L connecting the second axis O2 and the third axis O3 in a plan view from the axial direction of the fourth axis O4. That is, the second axis O2, the third axis O3, and the fourth axis O4 are in approximately the same position in the y-axis direction. In this embodiment, the straight line L coincides with the longitudinal centerline of the second arm 23. With this configuration, the weight is balanced on both sides via the straight line L, and excessive vibration can be prevented or suppressed when the robot arm 20 is driven. As a result, the robot 2 has excellent vibration damping properties.

[0054] Thus, the robot 2 includes a base 21, a first arm 22 connected to the base 21 and rotating around a first axis O1, a second arm 23 connected to the first arm 22 and rotating around the axis of a second axis O2 parallel to the first axis O1, a first shaft, the tip shaft 241, connected to the second arm 23 and moving in the axial direction of a third axis O3 parallel to the second axis O2, and also rotating around the axis of the third axis O3, a first motor, the motor 281 provided on the second arm 23 and driving the tip shaft 241 to move in the axial direction of the third axis O3, and a second shaft, the tip shaft 2 The robot arm 20 comprises a motor 271, which is a second motor that drives the 41 to rotate around the third axis O3; a transmission shaft 29, which is a second shaft that is positioned along the fourth axis O4, which is different from the third axis O3 and parallel to the third axis O3, and transmits the driving force of the motor 281 to the tip shaft 241 via a connecting member 244; and a pulley 291, which is positioned so that its center of rotation coincides with the central axis of the transmission shaft 29 and transmits the driving force from the motor 271 to the tip shaft 241. The transmission shaft 29, when viewed from the axial direction of the fourth axis O4, coincides with the straight line L connecting the second axis O2 and the third axis O3. This balances the weight on both sides along the straight line L, preventing or suppressing excessive vibration when the robot arm 20 is driven. As a result, the robot 2 has excellent vibration damping properties.

[0055] Furthermore, the rotation centers of motors 271 and 281 are located on a straight line L. In other words, motors 271 and 281 are also located on the same straight line as the tip shaft 241 and the transmission shaft 29. With this configuration, the weight balance on both sides of the straight line L is further improved, and excessive vibration can be more effectively prevented or suppressed when the robot arm 20 is driven. In particular, this configuration is advantageous when the weights of motors 271 and 281 are different, and consequently when the weights of the u-drive unit 27 and the z-drive unit are different.

[0056] Thus, the rotation centers of the first motor, motor 281, and the second motor, motor 271, coincide with the straight line L connecting the second axis O2 and the third axis O3. This results in a better weight balance on both sides along the straight line L, making it possible to more effectively prevent or suppress excessive vibrations when the robot arm 20 is driven.

[0057] Furthermore, the distance between the rotation center of the first motor, motor 281, and the second axis O2 is shorter than the distance between the rotation center of motor 281 and the fourth axis O4, and the distance between the rotation center of the second motor, motor 271, and the second axis O2 is shorter than the distance between the rotation center of motor 271 and the fourth axis O4. This allows the center of gravity of the second arm 23 to be positioned towards the base end. Therefore, it is possible to suppress the inertia from becoming too large when driving the robot arm 20. As a result, it is possible to suppress an increase in power consumption and suppress excessive heat generation of components such as regenerative resistors.

[0058] Furthermore, as mentioned above, the pulley 291 is provided with a through hole 290 through which the second shaft, the transmission shaft 29, is inserted, and the transmission shaft 29 and the pulley 291 rotate independently. This allows the rotation center of the pulley 291 to be positioned on the straight line L. Therefore, the weight balance is further improved on both sides of the straight line L compared to when the pulley 291 is positioned on either side of the straight line L. Thus, excessive vibration can be more effectively prevented or suppressed when the robot arm 20 is driven.

[0059] Similarly, in this embodiment, the u-drive unit 27 is a unit in which the motor 271 and the position sensor 273 are fixed coaxially, but the present invention is not limited to this, and the motor 271 and the position sensor 273 may be arranged in different positions from each other.

[0060] Similarly, in this embodiment, the z-drive unit 28 is a unit in which the motor 281 and the position sensor 283 are fixed coaxially, but the present invention is not limited to this, and the motor 281 and the position sensor 283 may be arranged in different positions from each other.

[0061] <Second Embodiment> Figure 5 is a schematic plan view showing the inside of the second arm of a second embodiment of the robot of the present invention.

[0062] The following describes a second embodiment of the robot of the present invention with reference to this figure, but the differences from the first embodiment will be explained below.

[0063] As shown in Figure 5, in this embodiment, the u-drive unit 27 and the z-drive unit 28 are arranged on opposite sides of each other via a straight line L. In the illustrated configuration, the motors 271 and 281 are arranged symmetrically with respect to the straight line L, with their centers of rotation being symmetrical. This allows for a good balance of weight on both sides via the straight line L, and enables the u-drive unit 27 and the z-drive unit 28 to be positioned at the same location in the y-axis direction. Therefore, the length of the second arm 23 in the y-axis direction can be designed to be shorter than in the first embodiment. As a result, vibration damping is improved, and the robot 2 can be made smaller.

[0064] Furthermore, if the weights of the u-drive unit 27 and the z-drive unit 28 are different, it is preferable to take their balance into consideration and adjust the distance from the straight line L accordingly.

[0065] Thus, the first motor, motor 281, and the second motor, motor 271, are arranged symmetrically with respect to the straight line connecting the second axis O2 and the third axis O3. This provides excellent vibration damping and allows for miniaturization of the robot 2.

[0066] Furthermore, the first motor, motor 281, and the second motor, motor 271, are positioned between the second axis O2 and the fourth axis O4. This allows for a more effective miniaturization of the robot 2.

[0067] <Third Embodiment> Figure 6 is a schematic plan view showing the interior of the second arm of a third embodiment of the robot of the present invention.

[0068] The following describes a third embodiment of the robot of the present invention with reference to this figure, but the differences from the second embodiment will be explained below.

[0069] As shown in Figure 6, in this embodiment, the u-drive unit 27 and the z-drive unit 28 are located on the +y-axis side of the second axis O2. That is, the first motor 281 and the second motor 271 are located on the opposite side of the third axis from the second axis O2. This allows the center of gravity of the second arm 23 to be moved further towards the base end. Therefore, it is possible to suppress the inertia from becoming too large when driving the robot arm 20. As a result, it is possible to suppress the increase in power consumption and the excessive heat generation of components such as regenerative resistors.

[0070] <Fourth Embodiment> Figure 7 is a partial cross-sectional view showing the inside of the second arm 23 of the fourth embodiment of the robot of the present invention.

[0071] The fourth embodiment of the present invention will be described below with reference to this figure, but the differences from the third embodiment will be explained below.

[0072] As shown in Figure 7, in this embodiment, the drive unit 26 is provided so as to protrude from the -z axis side of the second arm 23. That is, the drive unit 26 is provided in a position that does not overlap with the u drive unit 27, belt 274, z drive unit 28, and belt 284 in the axial direction of the z axis. This makes it possible to reduce interference between the drive unit 26 and belts 274 and 284 without increasing the size of the second arm 23.

[0073] Although the robot of the present invention has been described above based on the illustrated embodiment, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other components may be added.

[0074] Furthermore, although the robot arm has three rotation axes in the above embodiment, the present invention is not limited to this, and the number of rotation axes of the robot arm may be, for example, two, or four or more. In other words, although the number of arms is three in the above embodiment, the present invention is not limited to this, and the number of arms may be, for example, two, or four or more. [Explanation of symbols]

[0075] 1...Control device, 2...Robot, 7...End effector, 11...Robot control unit, 12...Motor control unit, 13...Display control unit, 14...Memory unit, 15...Reception unit, 20...Robot arm, 21...Base, 22...First arm, 23...Second arm, 24...Third arm, 25...Drive unit, 26...Drive unit, 27...U-drive unit, 28...Z-drive unit, 29...Transmission shaft (second shaft), 31...Gripping unit, 32...Side gauge, 33...Stop side gauge, 41...Display device, 42...Input device, 71...Mounting unit, 72...Motor, 100...Robot system, 200...Cable, 230...Housing, 231...Base unit, 232 ...Top plate, 233...Side wall, 241...Tip shaft (first shaft), 242...Pulley, 243...Belt, 244...Connecting member, 245...Spline nut, 246...Ball screw nut, 247...Bearing, 251...Motor, 252...Gear reducer, 253...Position sensor, 261...Motor, 262...Gear reducer, 263...Position sensor, 271...Motor, 273...Position sensor, 274...Belt, 281...Motor, 283...Position sensor, 284...Belt, 290...Through hole, 291...Pulley (intermediate member), 292...Large diameter section, 293...Small diameter section, L...Straight line, O1...First shaft, O2...Second shaft, O3...Third shaft, O4...Fourth shaft

Claims

1. Base and, A first arm connected to the base and rotating around a first axis, A second arm connected to the first arm and rotating around a second axis parallel to the first axis, A first shaft is connected to the second arm and moves in the axial direction of a third axis parallel to the second axis, and rotates around the third axis, A first motor is provided on the second arm, has an output shaft, and drives the first shaft to move in the axial direction of the third shaft, A second motor is provided on the second arm, has an output shaft, and drives the first shaft to rotate around the third axis, A second shaft is positioned along a fourth axis that is different from the third axis and parallel to the third axis, and is connected to the first shaft via a connecting member, A first belt transmission mechanism having a first belt stretched over the output shaft of the first motor, which transmits the driving force of the first motor to the second shaft, A second belt transmission mechanism having a second belt stretched over the output shaft of the second motor, which transmits the driving force of the second motor to the first shaft, Equipped with, When viewed from the axial direction of the fourth axis, the second shaft coincides with the straight line connecting the second axis and the third axis. The first motor and the second motor are arranged on opposite sides of each other via the straight line. The distance between the rotation center of the first motor and the second shaft is shorter than the distance between the rotation center of the first motor and the fourth shaft. The distance between the rotation center of the second motor and the second axis is shorter than the distance between the rotation center of the second motor and the fourth axis. A robot characterized in that the first belt and the second belt are positioned differently in the axial direction of the fourth axis.

2. The robot according to claim 1, wherein the first motor and the second motor are arranged between the second axis and the fourth axis.

3. The robot according to claim 1, wherein the first motor and the second motor are arranged on the opposite side of the third axis with respect to the second axis.

4. The robot according to claim 1, wherein the distance between the rotation center of the first motor and the straight line is different from the distance between the rotation center of the second motor and the straight line.

5. The robot according to claim 1, wherein, when viewed from the axial direction of the fourth axis, the first belt of the first belt transmission mechanism and the second belt of the second belt transmission mechanism intersect.

6. Base and, A first arm connected to the base and rotating around a first axis, A second arm connected to the first arm and rotating around a second axis parallel to the first axis, A first shaft is connected to the second arm and moves in the axial direction of a third axis parallel to the second axis, and rotates around the third axis, A first motor is provided on the second arm, has an output shaft, and drives the first shaft to move in the axial direction of the third shaft, A second motor is provided on the second arm, has an output shaft, and drives the first shaft to rotate around the third axis, A second shaft is positioned along a fourth axis that is different from the third axis and parallel to the third axis, and is connected to the first shaft via a connecting member, A first belt transmission mechanism having a first belt stretched over the output shaft of the first motor, which transmits the driving force of the first motor to the second shaft, A second belt transmission mechanism having a second belt stretched over the output shaft of the second motor, which transmits the driving force of the second motor to the first shaft, Equipped with, When viewed from the axial direction of the fourth axis, the second shaft coincides with the straight line connecting the second axis and the third axis. The first motor and the second motor are aligned with the straight line connecting the second shaft and the third shaft. A robot characterized in that the first belt and the second belt are positioned differently in the axial direction of the fourth axis.

7. The robot according to claim 6, wherein the first motor and the second motor are positioned differently from the second shaft when viewed from the axial direction of the fourth axis.

8. The robot according to any one of claims 1 to 7, wherein the second shaft has a ball screw nut, and the connecting member is attached to the ball screw nut.

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