CN116460827A - Robot - Google Patents

Abstract

The invention provides a robot with excellent vibration damping performance. The robot is characterized by comprising: a base station; a first arm connected to the base and rotatable about a first axis; a second arm connected to the first arm and rotatable about a second axis parallel to the first axis; a first shaft body connected to the second arm and rotated about a third axis parallel to the second axis; a first support portion provided on the second arm and rotatably supporting the first shaft body; and a second support portion connected to the second arm and rotatably supporting the first shaft body at a position different from the first support portion in an axial direction of the third shaft.

Description

Robot

Technical Field

The present invention relates to robots.

Background

In recent years, in factories, automation of operations performed manually by various robots or peripheral devices of the robots has been accelerated due to an increase in labor costs and insufficient talents. Examples of the various robots include the SCARA robot described in patent document 1.

The SCARA 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 working shaft connected to the second arm and being lifted and rotated, and a working shaft lifting mechanism for lifting and lowering the working shaft.

The work shaft lifting mechanism further includes: a lifting belt for transmitting the driving force of the motor for lifting the working shaft through the driving belt wheel and the driven belt wheel; a vertically movable bracket rotatably holding the operation shaft in a state of being fixed to the lifting belt, and being moved up and down integrally with the operation shaft in accordance with the conveyance of the lifting belt; and a guide shaft for guiding the lifting movement of the up-and-down movement bracket.

Patent document 1: japanese patent laid-open No. 2003-285282

In such a robot, the working shaft may vibrate, particularly during work. In this case, the accuracy of the robot performing the work may be lowered.

Disclosure of Invention

The present invention has been made in order to solve at least some of the above problems, and can be achieved as follows.

The robot of the present invention is characterized by comprising: a base station; a first arm connected to the base and rotatable about a first axis; a second arm connected to the first arm and rotatable about a second axis parallel to the first axis; a first shaft body connected to the second arm and rotated about a third axis parallel to the second axis; a first support portion provided on the second arm and rotatably supporting the first shaft body; and a second support portion connected to the second arm and rotatably supporting the first shaft body at a position different from the first support portion in an axial direction of the third shaft.

Drawings

Fig. 1 is a side view showing a first embodiment of a robot according to the present invention.

Fig. 2 is a block diagram illustrating the robot system shown in fig. 1.

Fig. 3 is a partial cross-sectional view showing the inside of a second arm provided in the mechanical arm shown in fig. 1.

Fig. 4 is a sectional view taken along line A-A of the robot arm shown in fig. 3.

Fig. 5 is a partial cross-sectional view schematically showing the interior of a second arm provided in a second embodiment of the robot of the present invention.

Fig. 6 is a partial cross-sectional view schematically showing the inside of a second arm provided in a third embodiment of the robot of the present invention.

Description of the reference numerals

1 control device, 2 robot, 4 rotation support part, 5 rotation support part, 7 end effector, 11 robot control part, 12 motor control part, 13 display control part, 14 storage part, 15 receiving part, 20 robot arm, 21 base, 22 first arm, 23 second arm, 24 third arm, 25 driving unit, 26 driving unit, 27 u driving unit, 28 z driving unit, 41 support part, 42 connection part, 42A first part, 42B second part, 70 end effector setting part, 72 motor, 100 robot system, 200 cable, 230 housing, 230C recess, 231 base part, 231A bottom, 231B side wall part, 232 cover, 241 front end shaft body, 242 rotation support part, 243 ball screw nut, 243A inner ring, 243B outer ring, 244 spline nut, 244A inner ring, 244B outer ring, 245 outer cylinder, 246 rotary body, 251 motor, 252 speed reducer, 253 position sensor, 261 motor, 262 speed reducer, 263 position sensor, 271 motor, 273 position sensor, 274 belt, 275 belt pulley, 281 motor, 283 position sensor, 284 belt, 285 belt pulley, 291 front end shaft body, 292 rotary support member, 293 spline nut, 293A inner ring, 293B outer ring, 294 outer cylinder, 295 rotary body, 301 transmission shaft body, 302 rotary support portion, 303 ball screw nut, 304 belt pulley, 310 connecting member, O1 first shaft, O2 second shaft, O3 third shaft, O4 fourth shaft.

Detailed Description

The robot according to the present invention will be described in detail below based on preferred embodiments shown in the drawings.

First embodiment

Fig. 1 is a side view showing a first embodiment of a robot according to the present invention. Fig. 2 is a block diagram of the robotic system shown in fig. 1. Fig. 3 is a partial cross-sectional view showing the inside of a second arm provided in the mechanical arm shown in fig. 1. Fig. 4 is a cross-sectional view of the mechanical arm shown in fig. 3 taken along line A-A.

In fig. 1, 3 and 4, for convenience of explanation, the x-axis, the y-axis and the z-axis are illustrated as 3 axes orthogonal to each other. Hereinafter, a direction parallel to the x-axis is also referred to as an "x-axis direction", a direction parallel to the y-axis is also referred to as a "y-axis direction", and a direction parallel to the z-axis is also referred to as a "z-axis direction". Hereinafter, the tip side of each arrow shown in the drawing is referred to as "+ (positive)", the base side is referred to as "- (negative)", the direction parallel to the +x-axis direction is also referred to as "+x-axis direction", the direction parallel to the-x-axis direction is also referred to as "+y-axis direction", the direction parallel to the +y-axis direction is also referred to as "+y-axis direction", the direction parallel to the-y-axis direction is also referred to as "+z-axis direction", and the direction parallel to the-z-axis direction is also referred to as "+z-axis direction". The direction around the z-axis and the direction around the axis parallel to the z-axis are also referred to as "u-axis direction".

In the following description, for convenience of explanation, the +z-axis direction, that is, the upper side in fig. 1, 3, and 4 is also referred to as "upper" or "upper", and the-z-axis direction, that is, the lower side is also referred to as "lower" or "lower". The manipulator 20 is referred to as a "base end" on the base 21 side in fig. 1, and is referred to as a "tip" on the opposite side, i.e., on the end effector 7 side. In fig. 1, the z-axis direction, i.e., the up-down direction, is referred to as the "vertical direction", and the x-axis direction and the y-axis direction, i.e., the left-right direction, are referred to as the "horizontal direction".

The robot system 100 shown in fig. 1 and 2 is a device used for operations such as holding, conveying, 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.

The control device 1 is disposed at a position different from the robot 2, that is, at the outside of the robot 2. In the illustrated configuration, the robot 2 and the control device 1 are electrically connected (hereinafter, also simply referred to as "connection") by the cable 200, but the present invention is not limited thereto, and the cable 200 may be omitted and communication may be performed wirelessly. That is, the robot 2 and the control device 1 may be connected by wired communication, or may be connected by wireless communication.

In the illustrated construction, the robot 2 is a horizontal multi-joint robot, i.e. a SCARA robot.

As shown in fig. 1 to 3, the robot 2 includes a base 21, a first arm 22, a second arm 23, and a third arm 24 as a work head. The first arm 22, the second arm 23, and the third arm 24 constitute the robot arm 20.

The robot 2 further includes: a driving unit 25 that rotates the first arm 22 with respect to the base 21; a driving unit 26 that rotates the second arm 23 with respect to the first arm 22; a u-drive unit 27 that rotates a distal end shaft body (first shaft body) 241 of the third arm 24 with respect to the second arm 23; and a z-drive unit 28 that moves the front end shaft body 241 along the z-axis with respect to the second arm 23.

As shown in fig. 1 and 2, the driving unit 25 is built in the base 21, and includes a motor 251 that generates driving force, a speed reducer 252 that reduces the driving force of the motor 251, and a position sensor 253 that detects the rotation angle of the motor 251 or the rotation shaft of the speed reducer 252.

The driving unit 26 is built in the housing 230 of the second arm 23, and includes a motor 261 that generates driving force, a speed reducer 262 that reduces the driving force of the motor 261, and a position sensor 263 that detects the rotation angle of the motor 261 or the rotation shaft of the speed reducer 262.

The u-drive unit 27 is built in the housing 230 of the second arm 23, and has a motor 271 that generates a driving force, and a position sensor 273 that detects the rotation angle of the rotation shaft of the motor 271.

The z-drive unit 28 is built in the housing 230 of the second arm 23, and has a motor 281 that generates a driving force, and a position sensor 283 that detects the rotation angle of the rotation shaft of the motor 281.

As the motor 251, the motor 261, the motor 271, and the motor 281, for example, a servo motor such as an AC servo motor or a DC servo motor can be used.

As the speed reducer 252 and the speed reducer 262, for example, a planetary gear type speed reducer, a wave gear device, or the like can be used. The position sensor 253, the position sensor 263, the position sensor 273, and the position sensor 283 may be, for example, angle sensors.

The driving unit 25, the driving unit 26, the u-driving unit 27, and the z-driving unit 28 are 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.

The base 21 is fixed to a floor surface, not shown, for example, by bolts or the like. A first arm 22 is connected to an upper end portion of the base 21. The first arm 22 is rotatable relative to the base 21 about a first axis O1 along the vertical direction. When the driving unit 25 that rotates the first arm 22 is driven, the first arm 22 rotates in a horizontal plane about the first axis O1 with respect to the base 21. Further, the rotation amount of the first arm 22 with respect to the base 21 can be detected by the position sensor 253.

A second arm 23 is connected to the distal end portion of the first arm 22. The second arm 23 is rotatable relative to the first arm 22 about a second axis O2 along the vertical direction. The axial direction of the first shaft O1 is the same as the axial direction of the second shaft O2. That is, the second axis O2 is parallel to the first axis O1. When the driving unit 26 that rotates the second arm 23 is driven, the second arm 23 rotates in a horizontal plane about the second axis O2 with respect to the first arm 22. In addition, the driving of the second arm 23 with respect to the first arm 22, specifically, the rotation amount can be detected by the position sensor 263. That is, the second axis O2 is the center of the output rotation axis of the speed reducer 262.

As shown in fig. 3, the second arm 23 includes a housing 230, and the housing 230 includes a base portion 231 and a cover 232. In the base 231, which is the inside of the housing 230, the driving unit 26, the u driving unit 27, and the z driving unit 28 are arranged in this order from the +y axis side.

As shown in fig. 4, the second arm 23 has a structure in which the inside of the base 231 is protected by a cover 232. The base portion 231 is a rigid body made of a metal material or the like, and functions to stably support the internal structure and to improve vibration damping performance. The cover 232 is made of a material having excellent lightweight such as a resin material.

The base portion 231 has a bottom 231A and a side wall portion 231B erected from the bottom 231A. The bottom 231A has a recess 230C. A part of the recess 230C on the-z axis side is opened toward the-z axis side, and a rotation support portion 242 is buried in the opened part, and the tip shaft body 241 is inserted.

The bottom 231A has a plate shape or a block shape having a thickness in the z-axis direction. The shape of the bottom 231A as viewed in the z-axis direction is not particularly limited, and may be rectangular or elliptical, for example.

The side wall 231B is provided over the entire periphery of the edge of the +z-axis side surface of the bottom 231A. However, the side wall 231B is not limited to this configuration, and may be provided at the +x-axis side and the-x-axis side edge.

A third arm 24 is provided at the distal end portion of the second arm 23. The third arm 24 includes a distal end shaft body 241 and a rotation support portion 242 rotatably supporting the distal end shaft body 241.

The tip shaft body 241 is rotatable about a third axis O3 along the vertical direction with respect to the second arm 23, and is movable (vertically movable) in the vertical direction. The front end shaft 241 is the foremost arm of the robot arm 20.

A ball screw nut 243 and a spline nut 244 are provided in the middle of the front end shaft 241 in the longitudinal direction, and the front end shaft 241 is supported by these. These ball screw nuts 243 and spline nuts 244 are disposed so as to be separated from the +z axis side in this order.

The ball screw nut 243 includes an inner ring 243A and an outer ring 243B concentrically disposed on the outer peripheral side of the inner ring 243A. A plurality of balls, not shown, are disposed between the inner ring 243A and the outer ring 243B, and the inner ring 243A and the outer ring 243B rotate relative to each other as the balls move.

The inner ring 243A has a portion exposed from the outer ring 243B, and a belt 284 described later is wound around the exposed portion. The inner ring 243A has a distal end shaft body 241 inserted therein, and the distal end shaft body 241 is supported so as to be movable along the z-axis as will be described later. The outer ring 243B is fixed to the base 231.

The spline nut 244 has an inner ring 244A and an outer ring 244B concentrically arranged on the outer peripheral side of the inner ring 244A. A plurality of balls, not shown, are disposed between the inner race 244A and the outer race 244B, and the inner race 244A and the outer race 244B rotate relative to each other as the balls move.

The inner race 244A has a portion exposed from the outer race 244B, and a belt 274 described later is wound around the exposed portion. The inner ring 244A has a tip shaft body 241 inserted therein, and the tip shaft body 241 is rotatably supported about the z-axis, that is, in the u-axis direction. The outer ring 244B is fixed to a recess 230C of the base 231 described later.

Further, a rotation support portion 242 is provided on the-z axis side of the spline nut 244. The rotation support portion 242 is a first support portion having an outer tube 245 and a rotation body 246 provided inside the outer tube 245. The outer tube 245 is fixed to the base portion 231 in the housing 230 of the second arm 23. On the other hand, the rotary body 246 is fixed to the tip shaft body 241, but is supported rotatably together with the tip shaft body 241 on the outer cylinder 245 about the z-axis, that is, in the u-axis direction.

When the u-drive unit 27 that rotates the front end shaft 241 is driven, the front end shaft 241 rotates in the forward and reverse directions, i.e., rotates about the z-axis. Further, the rotation amount of the tip shaft body 241 with respect to the second arm 23 can be detected by the position sensor 273.

When the z driving unit 28 for moving the front end shaft 241 along the z axis is driven, the front end shaft 241 moves in the up-down direction, that is, the z axis. Further, the movement amount of the tip shaft body 241 with respect to the z-axis direction of the second arm 23 can be detected by the position sensor 283.

Further, various end effectors are detachably coupled to the distal end portion of the distal end shaft body 241. The end effector is not particularly limited, and examples thereof include an end effector for gripping a workpiece, an end effector for processing a workpiece, and an end effector for inspection. In the present embodiment, the end effector 7 is detachably coupled.

In the present embodiment, the end effector 7 does not form a constituent element of the robot 2, but a part or the whole of the end effector 7 may form a constituent element of the robot 2. In the present embodiment, the end effector 7 does not form a constituent element of the robot arm 20, but a part or the whole of the end effector 7 may form a constituent element of the robot arm 20.

In the present embodiment, the end effector 7 is detachable from the robot arm 20, but the present invention is not limited thereto, and for example, the end effector 7 may not be detachable from the robot arm 20.

As shown in fig. 2, the control device 1 includes 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 driving of each unit of the robot system 100 such as the motors 72 of the robot 2 and the end effector 7.

In the control device 1, communication is allowed between the robot control unit 11, the motor control unit 12, the display control unit 13, the storage unit 14, and the reception unit 15, respectively. That is, 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.

In addition, the robot 2 and the end effector 7 are connected to the control device 1 by wired or wireless communication, respectively.

The robot control unit 11 controls driving of the robot 2, that is, driving of the arm 20 and the like. The robot control unit 11 is a computer having a program such as an OS installed thereon. The robot control unit 11 includes, for example, a CPU as a processor, a RAM, and a ROM in which a program is stored. The functions of the robot control unit 11 can be realized by executing various programs by a CPU, for example.

The motor control section 12 controls driving of the motor 72. The motor control unit 12 is a computer having a program such as an OS installed thereon. The motor control unit 12 includes, for example, a CPU as a processor, a RAM, and a ROM in which a program is stored. The functions of the motor control unit 12 can be realized by executing various programs by a CPU, for example.

The display control unit 13 has a function of causing a display device, not shown, to display various screens, characters, and the like, such as a window. The function of the display control unit 13 can be realized by a GPU, for example.

The storage unit 14 has a function of storing various information (including data, programs, and the like). The storage unit 14 stores a control program and the like. The function of the storage unit 14 can be realized by a so-called external storage device (not shown) such as a ROM.

The receiving unit 15 has a function of receiving an input from an input device not shown. The function of the receiving unit 15 can be realized by an interface circuit, for example.

Next, the inside of the second arm 23 will be described.

As shown in fig. 3, in the robot 2, a u-drive unit 27 that rotates the third arm 24 about the z-axis, a z-drive unit 28 that moves the third arm 24 along the z-axis, a belt 274, and a belt 284 are provided in the housing 230 of the second arm 23.

As shown in fig. 3, the u-drive unit 27 has a pulley 275 in addition to the motor 271 and the position sensor 273 described above. The position sensor 273, the motor 271, and the pulley 275 are arranged in this order from the +z axis side, and are fixed to the bottom of the recess 230C. The pulley 275 is fixed to a rotation shaft of the motor 271, and a rotation force of the motor 271 is transmitted to the pulley 275.

The pulley 275 is coupled to the inner race 244A of the spline nut 244 provided to the front end shaft body 241 by a belt 274. The belt 274 is an endless belt wound around the pulley 275 and the inner race 244A, and has teeth, not shown, on the inner side thereof, that is, on the pulley 275 and the inner race 244A side. The teeth of the belt 274 mesh with the teeth, not shown, of the exposed portions of the pulley 275 and the inner race 244A, respectively.

In such a u-drive unit 27, the rotational force of the motor 271 is transmitted to the belt 274 via the pulley 275, and the belt 274 rotates. By the rotation of the belt 274, the rotational force thereof is transmitted to the front end shaft body 241 via the spline nut 244. This rotational force is transmitted to the tip shaft body 241 via the inner peripheral portion of the inner ring 244A and a spline groove, not shown, of the tip shaft body 241, and the tip shaft body 241 is movable in the u-axis direction, that is, rotatable.

As shown in fig. 3, the z-drive unit 28 has a pulley 285 in addition to the motor 281 and the position sensor 283 described above. These are arranged in this order from the +z axis side of the position sensor 283, the motor 281, and the pulley 285. Pulley 285 is fixed to a rotation shaft of motor 281, and the rotational force of motor 281 is transmitted to pulley 285.

The pulley 285 is coupled to an exposed portion of the inner ring 243A of the ball screw nut 243 provided in the distal end shaft body 241 by a belt 284. The belt 284 is an endless belt wound around the pulley 285 and the inner ring 243A, and has teeth, not shown, on the inner side thereof, that is, on the pulley 285 and the inner ring 243A sides. The teeth of the belt 284 mesh with the teeth, not shown, of the pulley 285 and the inner race 243A, respectively.

In such a z-drive unit 28, the rotational force of the motor 281 is transmitted to the belt 284 via the pulley 285, and the belt 284 rotates. By the rotation of the belt 284, the rotational force is transmitted to the tip shaft body 241 via the inner ring 243A of the ball screw nut 243. The rotational force changes direction by the inner peripheral portion of the inner ring 243A and the ball screw groove of the tip shaft body 241, and the tip shaft body 241 can move along the z-axis, that is, can move up and down.

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

In the present embodiment, the z-drive unit 28 is a unit in which the motor 281 and the position sensor 283 are coaxially fixed, but the present invention is not limited to this, and the motor 281 and the position sensor 283 may be disposed at different positions.

The overall configuration of the robot 2 is described above. In such a robot 2, in order to improve the accuracy of the work, it is required to reduce vibration during driving. In particular, the tip shaft body 241 is subject to shaft vibration with respect to the third shaft O3 or vibration during lifting and lowering, which tends to reduce the vibration damping performance of the entire robot arm 20. Therefore, in the present invention, the vibration damping property is improved by adopting the following configuration. This will be described below.

As shown in fig. 4, the robot 2 includes a rotation support portion 4 as a second support portion. The rotation support portion 4 is a member that rotatably supports the distal end shaft body 241 at a position different from the rotation support portion 242 in the axial direction of the third shaft O3, and in the present embodiment, at a position separated upward. In fig. 4, the ball screw nut 243, the spline nut 244, the belt 274, and the belt 284 are omitted.

The rotation support portion 4 includes a support portion 41 for supporting the distal end shaft body 241 and a coupling portion 42 for coupling the support portion 41 and the base portion 231.

The support 41 may be, for example, an annular member such as a bearing. The support portion 41 rotatably supports the distal end shaft body 241 along the third axis O3.

As shown in fig. 4, in the present embodiment, the coupling portion 42 connects the side wall portion 231B of the base portion 231 with the support portion 41. In the present embodiment, the coupling portion 42 has a first portion 42A connected to the support portion 41 from the +x axis side and a second portion 42B connected to the support portion 41 from the-x axis side. That is, in the present embodiment, the connecting portion 42 has 2 arms. The first portion 42A and the second portion 42B have a portion extending in the z-axis direction from the side wall portion 231B and a portion extending in the x-axis direction, respectively.

The connection portion 42 may be formed of, for example, a plate-like member that connects the support portion 41 and the side wall portion 231B, not limited to such a configuration. In this case, the connecting portion 42 may be connected to the entire circumference of the support portion 41, or may be connected in a circular arc shape with a part of the defect.

According to such a configuration, the rotation support portion 242 as the first support portion and the rotation support portion 4 as the second support portion can support different positions in the longitudinal direction of the tip shaft body 241. That is, the tip shaft body 241 is supported at 2 different positions in the axial direction of the third shaft O3. Therefore, compared to a structure in which the front end shaft 241 is supported at 1 position, the front end shaft 241 can be effectively prevented or suppressed from generating shaft vibration when the robot arm 20 is driven or from vibrating when the front end shaft 241 is lifted or lowered. As a result, the accuracy of the work performed by the robot 2 can be improved. In addition, the occurrence of shaft vibration of the tip shaft body 241 due to the driving of the second arm can also be reduced.

Thus, the robot 2 includes: a base 21; a first arm 22 connected to the base 21 and rotatable about a first axis O1; a second arm 23 connected to the first arm 22 and rotatable about a second axis O2 parallel to the first axis O1; a front end shaft body 241 as a first shaft body connected to the second arm 23 and rotatable about a third axis O3 parallel to the second axis O2; a rotation support portion 242 as a first support portion provided on the second arm 23 and rotatably supporting the distal end shaft body 241; and a rotation support portion 4 as a second support portion connected to the second arm 23 and rotatably supporting the tip shaft body 241 at a position different from the rotation support portion 242 in the axial direction of the third shaft O3. This effectively prevents or suppresses the front end shaft 241 from being shaky when the robot arm 20 is driven or from vibrating when the front end shaft 241 is lifted or lowered. As a result, the accuracy of the work performed by the robot 2 can be improved.

The tip shaft body 241 as the first shaft is movable along the third axis O3, and the rotation support portion 242 as the first support portion and the rotation support portion 4 as the second support portion support the tip shaft body 241 movably along the third axis O3. Thus, the tip shaft 241 can move along the third axis O3, and work can be performed accurately.

The second arm 23 includes a base portion 231 and a cover 232 covering a structure supported by the base portion 231, and the rotation support portion 4 serving as a second support portion is connected to the base portion 231. By fixing the rotation support portion 4 to the base portion 231 having relatively high rigidity, it is possible to further effectively prevent or suppress the front end shaft body 241 from being subjected to shaft vibration when the mechanical arm 20 is driven or vibration when the front end shaft body 241 is lifted or lowered. As a result, the accuracy of the work performed by the robot 2 can be improved.

The base portion 231 includes a bottom portion 231A and a side wall portion 231B erected from the bottom portion 231A, and the rotation support portion 4 serving as a second support portion is fixed to the side wall portion 231B. Thereby, the second portion 42B of the coupling portion 42 of the rotation support portion 4 can be provided along the standing direction of the side wall portion 231B. Therefore, the space on the bottom 231A can be effectively utilized, and the second arm 23 can be miniaturized.

In the present embodiment, the support portion 41 of the rotation support portion 4 is provided on the +z-axis side of the rotation support portion 242. That is, the position where the rotation support portion 4 supports the front end shaft 241 is a position farther from the end effector setting portion 70 than the position where the rotation support portion 242 supports the front end shaft 241. This makes it possible to omit the provision of the rotation support portion 4 outside the cover 232, and to protect the rotation support portion 4 by the cover 232.

In this way, the front end shaft 241 as the first shaft has the end effector setting portion 70 for setting the end effector 7, and the distance between the position where the rotation support portion 4 as the second support portion supports the front end shaft 241 and the end effector setting portion 70 in the axial direction of the third shaft O3 is longer than the distance between the position where the rotation support portion 242 as the first support portion supports the front end shaft 241 and the end effector setting portion 70. This makes it possible to omit the provision of the rotation support portion 4 outside the cover 232, and to protect the rotation support portion 4 by the cover 232.

Second embodiment

Fig. 5 is a partial cross-sectional view schematically showing the interior of a second arm provided in a second embodiment of the robot of the present invention.

A second embodiment of the robot according to the present invention will be described below with reference to the drawings, and differences from the first embodiment will be described below.

As shown in fig. 5, in the present embodiment, the rotation support portion 4 rotatably supports the tip shaft body 241 at a position separated downward in the axial direction of the third shaft O3. In the present embodiment, the connecting portion 42 connects the edge portion of the bottom 231A of the base portion 231 with the rotation support portion 4. That is, the first portion 42A and the second portion 42B have a portion extending in the z-axis direction and a portion extending in the x-axis direction from the side wall portion 231B, respectively.

As described above, in the present embodiment, the distal end shaft body 241 as the first shaft body has the end effector setting portion 70 for setting the end effector 7, and the distance between the position where the rotational support portion 4 as the second support portion supports the distal end shaft body 241 and the end effector setting portion 70 in the axial direction of the third shaft O3 is shorter than the distance between the position where the rotational support portion 242 as the first support portion supports the distal end shaft body 241 and the end effector setting portion 70. Thus, for example, even when the relatively heavy end effector 7 is attached, the rotation support portion 4 can support a position closer to the end effector 7. Therefore, when the relatively heavy end effector 7 is attached, excellent vibration damping performance can be exhibited.

Third embodiment

Fig. 6 is a partial cross-sectional view schematically showing the inside of a second arm provided in a third embodiment of the robot of the present invention.

A third embodiment of the robot according to the present invention will be described below with reference to the drawings, and differences from the first embodiment will be described below.

As shown in fig. 6, the third arm 24 includes a distal end shaft body 291, a rotation support member 292 that rotatably supports the distal end shaft body 291, a transmission shaft body (second shaft body) 301, a rotation support portion 302 that is a third support portion that rotatably supports the transmission shaft body 301, and a coupling member 310 that couples the distal end shaft body 291 and the transmission shaft body 301. In the present embodiment, the tip shaft 291 is a ball spline shaft, and the transmission shaft 301 is a ball screw shaft.

The front end shaft body 291 is provided with a spline nut 293. The spline nut 293 has an inner ring 293A and an outer ring 293B concentrically arranged on the outer peripheral side of the inner ring 293A. A plurality of balls, not shown, are disposed between the inner ring 293A and the outer ring 293B, and the inner ring 293A and the outer ring 293B rotate relative to each other as the balls move.

The inner ring 293A has a portion exposed from the outer ring 293B, and the belt 274 is wound around the exposed portion. The inner ring 293A has a tip shaft body 291 inserted therein, and the tip shaft body 291 is rotatably supported around the z-axis, that is, in the u-axis direction.

A rotation support member 292 is provided on the-z axis side of the spline nut 293. The rotation support member 292 includes an outer tube 294 and a rotating body 295 provided inside the outer tube 294. The outer tube 294 is fixed to the base portion 231 within the housing 230 of the second arm 23. On the other hand, the rotary body 295 is fixed to the front end shaft body 291, but is supported by the outer tube 294 so as to be rotatable about the z-axis, that is, in the u-axis direction together with the front end shaft body 291.

When the u-drive unit 27 is driven, the front end shaft body 291 rotates positively and negatively, i.e., rotates, about the z-axis. Further, the rotation amount of the tip shaft body 291 with respect to the second arm 23 can be detected by the position sensor 273.

The coupling member 310 is attached to the +z-axis side end of the front end shaft 291 so as to be rotatable relative to the front end shaft 291 and not movable in the up-down direction.

The transmission shaft 301 is provided with a pulley 304 on the-z axis side. The pulley 304 is wound with the belt 284, and the rotational force of the motor 281 is transmitted to the transmission shaft 301 via the belt 284 and the pulley 304, whereby the transmission shaft 301 rotates in the forward and reverse directions, that is, rotates.

The ball screw nut 303 is provided at the +z-axis side end of the transmission shaft 301, and is attached to the coupling member 310 in a non-rotatable state. Accordingly, the ball screw nut 303 is rotated by the transmission shaft 301 driven by the z-drive unit 28, and moves in the up-down direction integrally with the coupling member 310 and the tip shaft 291. Further, the movement amount of the tip shaft body 291 in the z-axis direction of the second arm 23 can be detected by the position sensor 283.

The transmission shaft 301 is disposed closer to the +y axis than the tip shaft 291, and extends along a fourth axis O4 parallel to the third axis O3. The transmission shaft 301 is rotatably supported by the base 231 via a rotation support 302.

In such a robot 2, the transfer shaft 301 is supported at 2 positions in addition to the tip shaft 291. That is, the robot 2 includes a rotation support portion 302 as a third support portion and a rotation support portion 5 as a fourth support portion that rotatably supports the transmission shaft body 301 at a position different from the rotation support portion 302. The structure of the rotation support portion 5 is substantially the same as that of the rotation support portion 4, and therefore, a detailed description thereof will be omitted.

Thus, the robot 2 includes: a transmission shaft 301 as a second shaft, which is disposed along a fourth axis O4 different from and parallel to the third axis O3, and transmits the driving force of the motor 281 to a front end shaft 291 as a first shaft via a coupling member 310; a rotation support portion 302 as a third support portion provided on the second arm 23 and rotatably supporting the transmission shaft 301; and a rotation support portion 5 as a fourth support portion connected to the second arm 23 and rotatably supporting the transmission shaft body 301 at a position different from the rotation support portion 302 in the axial direction of the fourth shaft O4. Thus, even if the structure has the front end shaft body 291 and the transmission shaft body 301, excessive vibration of the robot arm 20 can be prevented or suppressed when the robot arm 20 is driven. As a result, the accuracy of the work performed by the robot 2 can be improved.

The positions of the rotation support portion 4 and the rotation support portion 5 in the z-axis direction may be the same or different. In different cases, the rotation support portion of the long shaft body out of the front end shaft body 291 and the transmission shaft body 301 is preferably provided at a high position. In this way, by making the position of the support appropriate according to the length of the shaft body, excessive vibration of the robot arm 20 can be more effectively prevented or suppressed. As a result, the accuracy of the work performed by the robot 2 can be improved.

In this way, the positions of the rotation support portion 4 as the second support portion and the rotation support portion 5 as the fourth support portion in the axial direction of the third axis O3 are preferably different. Thus, the position of the support can be made appropriate according to the length of the shaft body. Therefore, excessive vibration of the robot arm 20 can be more effectively prevented or suppressed. As a result, the accuracy of the work performed by the robot 2 can be improved.

While the robot according to the present invention has been described above with reference to the illustrated embodiment, the present invention is not limited to this, and the configuration of each part may be replaced with any configuration having the same function. In addition, any other structure may be added.

In the above embodiment, the number of the rotation shafts of the robot arm is 3, but the present invention is not limited thereto, and the number of the rotation shafts of the robot arm may be 2 or 4 or more, for example. That is, although the number of arms is 3 in the above embodiment, the present invention is not limited thereto, and the number of arms may be 2 or 4 or more, for example.

In the above embodiment, the tip shaft body 241 is rotatable about the third axis O3 along the vertical direction with respect to the second arm 23 and movable (vertically movable), but the present invention is not limited thereto, and for example, the tip shaft body 241 may be movable (vertically movable) only in the vertical direction. In this case, the u-drive unit 27 may be omitted from the second arm 23, and only the z-drive unit 28 may be mounted.

Claims (8)

1. A robot is characterized by comprising:

a base station;

a first arm connected to the base and rotatable about a first axis;

a second arm connected to the first arm and rotatable about a second axis parallel to the first axis;

a first shaft body connected to the second arm and rotated about a third axis parallel to the second axis;

a first support portion provided on the second arm and rotatably supporting the first shaft body; and

and a second support portion connected to the second arm and rotatably supporting the first shaft body at a position different from the first support portion in an axial direction of the third shaft.

2. The robot of claim 1, wherein the robot is configured to move the robot body,

the first shaft is movable along the third axis,

the first support portion and the second support portion support the first shaft body so as to be movable along the third axis.

3. The robot according to claim 1 or 2, wherein,

the second arm has a base portion and a cover covering a structure supported by the base portion,

the second support portion is connected to the base portion.

4. The robot according to claim 3, wherein,

the base portion has a bottom portion and a side wall portion provided upright from the bottom portion,

the second support portion is fixed to the side wall portion.

5. The robot of claim 1, wherein the robot is configured to move the robot body,

the first shaft body is provided with an end effector setting part for setting an end effector,

in the axial direction of the third shaft, the distance between the position where the second support portion supports the first shaft body and the end effector setting portion is longer than the distance between the position where the first support portion supports the first shaft body and the end effector setting portion.

6. The robot of claim 1, wherein the robot is configured to move the robot body,

the first shaft body is provided with an end effector setting part for setting an end effector,

in the axial direction of the third shaft, the distance between the position where the second support portion supports the first shaft body and the end effector setting portion is shorter than the distance between the position where the first support portion supports the first shaft body and the end effector setting portion.

7. The robot according to claim 1, comprising:

a second shaft body disposed along a fourth axis different from and parallel to the third axis, the second shaft body transmitting a driving force of a motor to the first shaft body via a coupling member;

a third support portion provided on the second arm and rotatably supporting the second shaft body; and

and a fourth support portion connected to the second arm and rotatably supporting the second shaft body at a position different from the third support portion in an axial direction of the fourth shaft.

8. The robot of claim 7, wherein the robot is configured to move the robot arm,

the second support portion and the fourth support portion are positioned differently in the axial direction of the third shaft.