JP2023105930A - robot - Google Patents

Abstract

To provide a robot that can be reduced in weight and is excellent in vibration damping.SOLUTION: The robot comprises: a base; a first arm, connected to the base, which turns around a first axis; a second arm, connected to the first arm, which turns around a second axis which is parallel to the first axis; and a shaft, connected to the second arm, which moves in an axial direction of a third axis which is parallel to the second axis or turns around the third axis. The second arm has a bottom part, a side wall part erected from the bottom part, and a cover surrounding a structure with the bottom part and the side wall part. The side wall part has a base-side area positioned at the base side, a tip-side area positioned at the shaft side, and an intermediate area positioned between the base-side area and the tip-side area, where at least one of the base-side area, the tip-side area, and the intermediate area is longer in length in an axial direction of the second axis than the other areas.SELECTED DRAWING: Figure 5

Description

The present invention relates to robots.

In recent years, due to soaring labor costs and a shortage of human resources in factories, the automation of work that has been done manually is accelerating with the use of various robots and their peripheral devices. Examples of such various robots include a SCARA robot as described in Patent Document 1, for example.

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, and a second arm connected to lift and rotate. and a work shaft elevating mechanism for elevating the work shaft.

The work shaft lifting mechanism includes a lifting belt that transmits the driving force of the work shaft lifting motor via a drive pulley and a driven pulley, and a work shaft that is fixed to the lifting belt so as to be rotatably held, It has a vertical movement bracket that vertically moves together with the work shaft as the lifting belt is conveyed, and a guide shaft that guides the vertical movement of the vertical movement bracket.

Japanese Patent Application Laid-Open No. 2003-285282

In such a robot, especially the second arm is required to be lightweight and to have high vibration damping properties. If the weight of the base portion of the second arm is reduced, the second arm is likely to be twisted during operation, deteriorating the damping performance. On the other hand, if the base portion of the second arm is thickened, the damping performance is improved, but the weight of the second arm is increased. Thus, it is difficult to achieve both weight reduction and high damping performance.

The present invention has been made to solve the problems described above, and can be realized by the following.

The robot of the present invention comprises a base,
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 shaft connected to the second arm and moving in an axial direction of a third axis parallel to the second axis or rotating around the third axis;
the second arm has a bottom portion, a side wall portion erected from the bottom portion, and a cover that surrounds the structure with the bottom portion and the side wall portion;
The side wall portion has a base-side region positioned on the base side, a tip-side region positioned on the shaft side, and an intermediate region positioned between the base-side region and the tip-side region. ,
At least one of the base-side region, the tip-side region, and the intermediate region has a longer length in the axial direction of the second shaft than the other regions.

It is a side view showing a first embodiment of the robot of the present invention. 2 is a block diagram of the robot system shown in FIG. 1; FIG. 2 is a partial cross-sectional view showing the inside of a second arm included in the robot arm shown in FIG. 1; FIG. FIG. 4 is a cross-sectional view of the base portion of the second arm shown in FIG. 3 taken along the line AA; FIG. 3 is a side view schematically showing a base portion of a second arm shown in FIG. 1; FIG. 11 is a side view schematically showing a base portion of a second arm provided in the second embodiment of the robot of the present invention; FIG. 11 is a side view schematically showing a base portion of a second arm included in the third embodiment of the robot of the present invention;

DETAILED DESCRIPTION OF THE INVENTION A robot of the present invention will now be described in detail based on preferred embodiments shown in the accompanying drawings.
<First Embodiment>
FIG. 1 is a side view showing the first embodiment of the robot of the present invention. FIG. 2 is a block diagram of the robot system shown in FIG. 3 is a partial cross-sectional view showing the inside of a second arm included in the robot arm shown in FIG. 1. FIG. 4 is a cross-sectional view of the base portion of the second arm shown in FIG. 3, taken along the line AA. 5 is a side view schematically showing the base portion of the second arm shown in FIG. 1. FIG.

1, 3 to 5, the x-axis, the y-axis and the z-axis are shown as three mutually orthogonal axes for convenience of explanation. Further, hereinafter, the direction parallel to the x-axis is also called "x-axis direction", the direction parallel to the y-axis is also called "y-axis direction", and the direction parallel to the z-axis is also called "z-axis direction". Further, hereinafter, the tip side of each illustrated arrow is called "+ (plus)", the base end side is called "- (minus)", and the direction parallel to the +x-axis direction is also called "+x-axis direction", The direction parallel to the -x-axis direction is also called the "-x-axis direction," the direction parallel to the +y-axis direction is also called the "+y-axis direction," and the direction parallel to the -y-axis direction is also called the "-y-axis direction." The direction parallel to the +z-axis direction is also called the "+z-axis direction", and the direction parallel to the -z-axis direction is also called the "-z-axis direction". Also, the direction around the z-axis and the direction around an axis parallel to the z-axis are also referred to as "u-axis direction".

Also, hereinafter, for convenience of explanation, the +z-axis direction, that is, the upper side in FIGS. Also called "lower". In addition, regarding the robot arm 20, the base 21 side in FIG. Also, the z-axis direction in FIG. 1, that is, the up-down direction, is defined as the "vertical direction", and the x-axis direction and the y-axis direction, that is, the horizontal direction, is defined as the "horizontal direction".

A robot system 100 shown in FIGS. 1 and 2 is, for example, a device used for work such as holding, transporting, assembling, and inspecting works such as electronic components and electronic equipment. The robot system 100 includes a control device 1, a robot 2, and an end effector 7.

Also, the control device 1 is arranged at a different position 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 "connection") by a cable 200, but the present invention is not limited to this, and the cable 200 is omitted, and wireless communication is possible. Communication may be performed by the method. That is, the robot 2 and the control device 1 may be connected by wired communication, or may be connected by wireless communication.

The robot 2, in the configuration shown, is a horizontal articulated robot, ie a SCARA robot.

As shown in FIGS. 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 working head. A robot arm 20 is composed of the first arm 22 , the second arm 23 and the third arm 24 .

The robot 2 also 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 , and a tip shaft of the third arm 24 . A u drive unit 27 that rotates the (shaft) 241 with respect to the second arm 23 and a z drive unit 28 that moves the tip shaft 241 with respect to the second arm 23 in the z-axis direction are provided.

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

The drive unit 26 is built in 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 rotating shaft of the motor 261 or the speed reducer 262. and a position sensor 263 that detects the rotation angle of the.

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 driving force and a position sensor 283 that detects the rotation angle of the rotation shaft of the motor 281 .

As the motors 251, 261, 271 and 281, for example, servo motors such as AC servo motors and DC servo motors 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. Also, the position sensor 253, the position sensor 263, the position sensor 273 and the position sensor 283 can be angle sensors, for example.

The drive unit 25, the drive unit 26, the u drive unit 27, and the z drive unit 28 are each connected to a corresponding motor driver (not shown) and controlled by the robot controller 11 of the controller 1 via the motor driver. .

The base 21 is, for example, fixed to a floor (not shown) with bolts or the like. A first arm 22 is connected to the upper end of the base 21 . The first arm 22 is rotatable about a first axis O<b>1 along the vertical direction with respect to the base 21 . When the drive unit 25 that rotates the first arm 22 is driven, the first arm 22 rotates about the first axis O1 with respect to the base 21 in the horizontal plane. Further, the position sensor 253 can detect the amount of rotation of the first arm 22 with respect to the base 21 .

A second arm 23 is connected to the tip of the first arm 22 . The second arm 23 is rotatable with respect to the first arm 22 around a second axis O2 along the vertical direction. 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 about the second axis O2 with respect to the first arm 22 in the horizontal plane. Further, the position sensor 263 can detect the drive of the second arm 23 with respect 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 speed reducer 262 .

As shown in FIG. 3 , the second arm 23 has a housing 230 having a base portion 231 and a cover 232 . Inside the 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.

The second arm 23 has a structure in which a cover 232 protects the internal structure supported by the base portion 231 . The base portion 231 is a rigid body made of a metal material or the like, and has the function of stably supporting the internal structure and enhancing the damping property. The cover 232 is made of a lightweight material such as a resin material.

The base portion 231 has a bottom portion 231A and side wall portions 231B erected from the bottom portion 231A. A concave portion 231C is provided in the bottom portion 231A. A part of the concave portion 231C on the -z-axis side is open to the -z-axis side. 241 is inserted.

A third arm 24 is installed at the tip of the second arm 23 . The third arm 24 has a tip shaft 241 and a rotation support member 242 that rotatably supports the tip shaft 241 .

The tip shaft 241 is rotatable about the third axis O3 along the vertical direction with respect to the second arm 23, and is vertically movable (liftable). This distal shaft 241 is the most distal arm of the robot arm 20 .

A ball screw nut 243 and a spline nut 244 are installed in the middle of the tip shaft 241 in the longitudinal direction, and the tip shaft 241 is supported by these. These ball screw nut 243 and spline nut 244 are spaced apart from the +z-axis side in this order.

The ball screw nut 243 has an inner ring 243A and an outer ring 243B concentrically arranged on the outer peripheral side of the inner ring 243A. A plurality of balls (not shown) are arranged 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, which will be described later, is wrapped around the exposed portion. Further, the inner ring 243A has the tip shaft 241 inserted thereinto, and supports the tip shaft 241 so as to be movable along the z-axis direction, as will be described later. Also, the outer ring 243B is fixed to the base portion 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 arranged between the inner ring 244A and the outer ring 244B, and the inner ring 244A and the outer ring 244B rotate relative to each other as the balls move.

The inner ring 244A has a portion exposed from the outer ring 244B, and a belt 274, which will be described later, is wrapped around the exposed portion. Further, the inner ring 244A inserts the tip shaft 241 thereinto and supports the tip shaft 241 so as to be rotatable around the z-axis, that is, in the u-axis direction. Further, the outer ring 244B is fixed to a recessed portion 231C of the base portion 231, which will be described later.

A rotation support member 242 is installed on the -z axis side of the spline nut 244 . The rotation support member 242 has an outer cylinder 245 and a rotor 246 provided inside the outer cylinder 245 . The outer cylinder 245 is fixed to the base portion 231 inside the housing 230 of the second arm 23 . On the other hand, the rotating body 246 is fixed to the tip shaft 241, but supported by the outer cylinder 245 so as to be rotatable around the z-axis together with the tip shaft 241, that is, in the u-axis direction.

When the u drive unit 27 that rotates the tip shaft 241 is driven, the tip shaft 241 rotates forward and backward around the z-axis, that is, rotates. Also, the position sensor 273 can detect the amount of rotation of the tip shaft 241 with respect to the second arm 23 .

Further, when the z drive unit 28 that moves the tip shaft 241 in the z-axis direction is driven, the tip shaft 241 moves in the vertical direction, that is, in the z-axis direction. Further, the position sensor 283 can detect the amount of movement of the tip shaft 241 in the z-axis direction with respect to the second arm 23 .

Various end effectors are detachably connected to the distal end portion of the distal shaft 241 . The end effector is not particularly limited, and includes, for example, those that grip objects to be transferred, those that process objects to be processed, those that are used for inspection, and the like. In this embodiment, the end effector 7 is detachably connected.

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

Also, in this embodiment, the end effector 7 is detachable from the robot arm 20 , but the present invention is not limited to this. 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 section 11, a motor control section 12 (end effector control section), a display control section 13, a storage section 14, and a reception section 15. , the robot 2, the motor 72 of the end effector 7, and the like.

Further, the control device 1 is configured such that the robot control unit 11, the motor control unit 12, the display control unit 13, the storage unit 14, and the reception unit 15 can communicate with each other. 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 through wired or wireless communication.

A robot 2 and an end effector 7 are connected to the control device 1 by wire or wireless communication.

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

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

The display control unit 13 has a function of displaying various screens such as windows and characters on a display device (not shown). The function of this display control unit 13 can be realized by, for example, a GPU.

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

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

Next, the inside of the second arm 23 will be described.
In the robot 2, as shown in FIG. 3, a u drive unit 27 for rotating the third arm 24 around the z-axis and a u-driving unit 27 for moving the third arm 24 in the z-axis direction are provided in the housing 230 of the second arm 23. A z-drive unit 28, a belt 274, and a belt 284 are provided.

As shown in FIG. 3, the u drive unit 27 has a pulley 275 in addition to the motor 271 and position sensor 273 previously described. The position sensor 273, the motor 271 and the pulley 275 are arranged in this order from the +z-axis side and fixed to the bottom of the recess 231C. The pulley 275 is fixed to the rotating shaft of the motor 271 and the torque of the motor 271 is transmitted to the pulley 275 .

Also, the pulley 275 is connected to an inner ring 244A of a spline nut 244 provided on the tip shaft 241 by a belt 274 . The belt 274 is an endless belt that is looped around the pulley 275 and the inner ring 244A, and has teeth (not shown) on its inner side, that is, on the side of the pulley 275 and the inner ring 244A. The teeth of the belt 274 mesh with the teeth (not shown) of the exposed portions of the pulley 275 and the inner ring 244A.

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. As the belt 274 rotates, its rotational force is transmitted to the tip shaft 241 via the spline nut 244 . This rotational force is transmitted to the tip shaft 241 via the inner circumference of the inner ring 244A and spline grooves (not shown) of the tip shaft 241, and the tip shaft 241 can move in the u-axis direction, that is, rotate.

As shown in FIG. 3, the z drive unit 28 has a pulley 285 in addition to the motor 281 and position sensor 283 previously described. The position sensor 283, motor 281 and pulley 285 are arranged in this order from the +z-axis side. The pulley 285 is fixed to the rotating shaft of the motor 281 and the torque of the motor 281 is transmitted to the pulley 285 .

Also, the pulley 285 is connected by a belt 284 to the exposed portion of the inner ring 243A of the ball screw nut 243 provided on the tip shaft 241 . The belt 284 is an endless belt that is looped around the pulley 285 and the inner ring 243A, and has teeth (not shown) on its inner side, that is, on the side of the pulley 285 and the inner ring 243A. The teeth of the belt 284 mesh with the teeth (not shown) of the pulley 285 and the inner ring 243A.

In such a z drive unit 28, the rotational force of the motor 281 is transmitted to the belt 284 via the pulley 285, causing the belt 284 to rotate. Due to the rotation of this belt 284 , the rotational force is transmitted to the tip shaft 241 via the inner ring 243A of the ball screw nut 243 . The direction of this rotational force is changed by the inner circumference of the inner ring 243A and the ball screw groove of the tip shaft 241, and the tip shaft 241 can move in the z-axis direction, that is, move up and down.

In this 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. They may be arranged at different positions.

Similarly, in this 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 are They may be arranged at positions different from each other.

Now, as described above, the second arm 23 includes the housing 230 having the base portion 231 and the cover 232 . Further, as shown in FIGS. 4 and 5, the base portion 231 has a bottom portion 231A and side wall portions 231B erected from the bottom portion 231A. The bottom portion 231A has a plate-like or block-like shape with a thickness in the z-axis direction.

The shape of the bottom portion 231A when viewed from the z-axis direction is not particularly limited, but may be rectangular or elliptical, for example.

In this embodiment, the side wall portion 231B is provided over the entire circumference of the edge portion of the +z-axis side surface of the bottom portion 231A. However, the configuration is not limited to this, and the side wall portions 231B may be provided at the edge portions on the +x-axis side and the −x-axis side.

Further, as shown in FIGS. 4 and 5, the bottom portion 231A and the side wall portion 231B form a recessed portion 231D having an opening 231E. Furthermore, the cover 232 covers the opening 231E of the recess 231D. Thereby, the structure in the recess 231D can be protected.

Here, the second arm 23 is required to be lightweight and have high damping properties. If the base portion 231 of the second arm 23 is made thin, the weight of the second arm 23 can be reduced, but the second arm 23 is likely to be twisted during operation, deteriorating the damping performance. On the other hand, if the base portion 231 of the second arm 23 is thickened, the damping performance is improved, but the weight of the second arm 23 is increased. Thus, it is difficult to achieve both weight reduction and high damping performance. The robot 2 has an effective configuration to solve such problems. This will be explained below.

As shown in FIG. 5, the side wall portion 231B has a base side region 23A, a tip side region 23B, and an intermediate region 23C.

The base-side region 23A is a portion of the base-side region 23A, the distal end-side region 23B, and the intermediate region 23C located closest to the base 21, that is, the +y-axis side. The drive unit 26 is arranged on the base portion 231 where the base side region 23A of the side wall portion 231B is located when viewed in the x-axis direction. The base-side region 23A is a region covering 20% or more and 40% or less of the total length of the side wall portion 231B in the y-axis direction from the most base end side.

The tip side region 23B is a portion of the base side region 23A, the tip side region 23B, and the intermediate region 23C located on the tip shaft 241 side, that is, on the -y axis side. A tip shaft 241 is arranged on the base portion 231 where the tip side region 23B of the side wall portion 231B is positioned when viewed from the x-axis direction. , the tip side region 23B is a region of 20% or more and 40% or less from the tip side of the total length of the side wall portion 231B in the y-axis direction.

The intermediate region 23C is a region positioned between the base side region 23A and the tip side region 23B. The u drive unit 27 and the z drive unit 28 are arranged on the base portion 231 where the intermediate region 23C of the side wall portion 231B is located when viewed in the x-axis direction. The intermediate region 23C is a region of 20% or more and 60% or less of the total length of the side wall portion 231B in the y-axis direction.

In the robot 2, at least one of the base side region 23A, the tip side region 23B, and the intermediate region 23C is longer than the other regions in the axial direction of the second axis O2, that is, the length in the z-axis direction. is long. In other words, at least one of the base side region 23A, the tip side region 23B and the intermediate region 23C is higher than the other regions.

In this embodiment, the tip side region 23B is higher than the base side region 23A and the intermediate region 23C. Therefore, when the second arm 23 operates, the distal region 23B is less likely to be twisted around the y-axis. Therefore, the damping property can be enhanced by the tip side region 23B. Further, since the base side region 23A and the intermediate region 23C are lower in height than the tip side region 23B, weight reduction can be maintained. In this way, in the robot 2, the side wall portion 231B is reinforced to improve the damping performance, and the weight of the other portions is reduced. Therefore, it is possible to achieve both weight reduction and excellent damping properties.

As described above, the robot 2 includes the base 21, the first arm 22 connected to the base 21 and rotating around the first axis O1, and the first arm 22 connected to the first axis O1. A second arm 23 that rotates about a parallel second axis O2, and a second arm 23 that is connected to the second arm 23 and moves in the axial direction of a third axis O3 that is parallel to the second axis O2 or about the third axis O3. and a rotating tip shaft 241 . The second arm 23 also has a bottom portion 231A, side wall portions 231B erected from the bottom portion 231A, and a cover 232 that surrounds the structure with the bottom portion 231A and the side wall portions 231B. The side wall portion 231B is positioned between the base side region 23A positioned on the side of the base 21, the tip side region 23B positioned on the side of the tip shaft 241, and the base side region 23A and the tip side region 23B. It has an intermediate region 23C, and at least one of the base side region 23A, the tip side region 23B, and the intermediate region 23C (in this embodiment, the tip side region 23B is more axially aligned with the second axis O2 than the other regions) length in is long. As a result, the side wall portion 231B is reinforced to enhance the damping performance, and the weight of other portions can be reduced. Therefore, it is possible to achieve both weight reduction and excellent damping properties.

In this embodiment, the tip side region 23B of the base side region 23A, the tip side region 23B, and the intermediate region 23C has a longer length in the axial direction of the second axis O2 than the other regions. The present invention is not limited to this, and as described in the second embodiment, the intermediate region 23C may have a longer length in the axial direction of the second axis O2 than the other regions. 23A may have a longer length in the axial direction of the second axis O2 than other regions.

Further, the base-side region 23A and the tip-side region 23B may be longer than the intermediate region 23C in the axial direction of the second axis O2, and the base-side region 23A and the intermediate region 23C may be longer than the tip-side region 23B. A configuration in which the length in the axial direction of the second axis O2 may be longer, and the length in the axial direction of the second axis O2 may be longer in the tip side region 23B and the intermediate region 23C than in the base side region 23A. may

In the present embodiment, the tip side region 23B is longer than the base side region 23A and the intermediate region 23C in the axial direction of the second axis O2. As a result, it is possible to effectively reinforce the tip portion, which is relatively prone to twisting. Therefore, damping property is further excellent.

In addition, it is preferable that the portion of the side wall portion 231B located on the +Y-axis side also has a longer length in the axial direction of the second axis O2 than the base-side region 23A and the intermediate region 23C. Thereby, damping property is further improved.

Further, the tip shaft 241, which is a shaft, is arranged so as to overlap with the tip side region 23B in plan view. In this way, the portion that supports the relatively heavy tip shaft 241 can be reinforced intensively. Therefore, damping property is further excellent.

The length of the distal region 23B in the axial direction of the second axis O2 may be constant along the y-axis direction, or may be configured to decrease toward the distal side, or toward the proximal side. It may have a decreasing configuration, or it may decrease toward the distal and proximal sides.

Further, the lengths of the base side region 23A and the intermediate region 23C in the axial direction of the second axis O2 may be the same or different, but the intermediate region 23C is preferably longer.

<Second embodiment>
FIG. 6 is a side view schematically showing the base portion of the second arm provided in the second embodiment of the robot of the present invention.

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

As shown in FIG. 6, in the present embodiment, the intermediate region 23C is longer than the base side region 23A and the tip side region 23B in the axial direction of the second axis O2. The lengths of the base side region 23A and the tip side region 23B in the axial direction of the second axis O2 are the same.

Thus, the intermediate region 23C is longer than the base side region 23A and the tip side region 23B in the axial direction of the second axis O2. As a result, the intermediate portion in the longitudinal direction of the second arm 23 can be reinforced, and twisting of the second arm 23 can be effectively suppressed. Therefore, damping property is further excellent.

The robot 2 also includes motors 271 and 281 that move the tip shaft 241, which is a shaft, in the axial direction of the third axis O3 or drive the tip shaft 241 around the third axis O3. 281 is arranged so as to overlap with the intermediate region 23C in plan view of a plane including the second axis O2 and the third axis O3. In this way, by predominantly reinforcing the portions that support the relatively heavy motors 271 and 281, the damping performance is further improved.

<Third Embodiment>
FIG. 7 is a side view schematically showing the base portion of the second arm provided in the third embodiment of the robot of the present invention.

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

As shown in FIG. 7, the third arm 24 includes a tip shaft 291, a rotation support member 292 that rotatably supports the tip shaft 291, a transmission shaft 301, and a rotation support member that rotatably supports the transmission shaft 301. 302 and a connecting member 310 that connects the tip shaft 291 and the transmission shaft 301 . In this embodiment, the tip shaft 291 is a ball spline shaft and the transmission shaft 301 is a ball screw shaft. That is, a tip shaft 291 and a transmission shaft 301 are included as those corresponding to the tip shaft (shaft) 241 in the first embodiment.

The tip shaft 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 arranged 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.

Also, the inner ring 293A has a portion exposed from the outer ring 293B, and the belt 274 is wrapped around the exposed portion. Further, the inner ring 293A inserts the tip shaft 291 thereinto and supports the tip shaft 291 so as to be rotatable around the z-axis, that is, in the u-axis direction.

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

When the u drive unit 27 is driven, the tip shaft 291 rotates forward and backward around the z-axis, that is, rotates. Also, the position sensor 273 can detect the amount of rotation of the tip shaft 291 with respect to the second arm 23 .

Also, a connecting member 310 is attached to the end of the tip shaft 291 on the +z-axis side so as to be rotatable with respect to the tip shaft 291 and unable to move in the vertical direction.

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

The ball screw nut 303 is provided at the end of the transmission shaft 301 on the +z-axis side, and is attached to the connecting member 310 described above so as not to rotate. Therefore, the ball screw nut 303 moves vertically together with the connecting member 310 and the tip shaft 291 when the transmission shaft 301 is rotated by the drive of the z drive unit 28 . Further, the position sensor 283 can detect the amount of movement of the tip shaft 291 relative to the second arm 23 in the z-axis direction.

The transmission shaft 301 is arranged on the +y-axis side of the tip shaft 291 and extends along the fourth axis O4 parallel to the third axis O3. The transmission shaft 301 is rotatably supported by the base portion 231 via a rotation support member 302 .

In the second arm 23 having such a configuration, the distal region 23B is a region that includes the distal shaft 291 and the transmission shaft 301 when viewed from the x-axis direction. Also, the intermediate region 23C is a region that includes the u drive unit 27 and the z drive unit 28 when viewed from the x-axis direction.

Then, among the base side region 23A, the tip side region 23B and the intermediate region 23C, the tip side region 23B, that is, the region corresponding to the position where the tip shaft 291 and the transmission shaft 301 are arranged, is second from the other regions. It is preferable that the length in the axial direction of the axis O2 is long. . Thereby, the effect of the present invention can be exhibited more remarkably.

Further, among the base side region 23A, the tip side region 23B, and the intermediate region 23C, the intermediate region 23C, that is, the region corresponding to the position where the u drive unit 27 and the z drive unit 28 are arranged, is the first region than the other regions. The length in the axial direction of the two axes O2 may be long. Even in this case, the effects of the present invention can be remarkably exhibited.

Although the robot of the present invention has been described above based on the illustrated embodiments, the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having similar functions. can be done. Also, other optional components may be added.

In the above embodiment, the number of rotation axes of the robot arm is three, but the present invention is not limited to this, and the number of rotation axes of the robot arm is, for example, two or four. It can be more than that. That is, 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.

In the above-described embodiment, the tip shaft 241 is rotatable about the third axis O3 along the vertical direction with respect to the second arm 23 and is vertically movable (liftable). However, it is not limited to this, and for example, the tip shaft 241 may be capable of only moving (up and down) in the vertical direction. In that case, the u drive unit 27 may be omitted from the second arm 23 and only the z drive unit 28 may be mounted.

DESCRIPTION OF SYMBOLS 1... Control apparatus, 2... Robot, 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 Table 22... First arm 23... Second arm 23A... Base side area 23B... Tip side area 23C... Intermediate area 24... Third arm 25... Drive unit 26... Movement unit 27... u drive unit 28 z drive unit 72 motor 100 robot system 200 cable 230 housing 231 base 231A bottom 231B side wall 231C recess 231D recess 231E... opening, 232... cover, 241... tip shaft, 242... rotation support member, 243... ball screw nut, 243A... inner ring, 243B... outer ring, 244... spline nut, 244A... inner ring, 244B... outer ring, 245... outer cylinder , 246... Rotator 251... Motor 252... Reducer 253... Position sensor 261... Motor 262... Reducer 263... Position sensor 271... Motor 273... Position sensor 274... Belt 275... Pulley , 281... Motor 283... Position sensor 284... Belt 285... Pulley 291... Tip shaft 292... Rotation support member 293... Spline nut 293A... Inner ring 293B... Outer ring 294... Outer cylinder 295... Rotation Body 301 Transmission shaft 302 Rotary support member 303 Ball screw nut 304 Pulley 310 Connecting member O1 First shaft O2 Second shaft O3 Third shaft O4 Fourth shaft

Claims (6)

a base;
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 shaft connected to the second arm and moving in an axial direction of a third axis parallel to the second axis or rotating around the third axis;
the second arm has a bottom portion, a side wall portion erected from the bottom portion, and a cover that surrounds the structure with the bottom portion and the side wall portion;
The side wall portion has a base-side region positioned on the base side, a tip-side region positioned on the shaft side, and an intermediate region positioned between the base-side region and the tip-side region. ,
The robot, wherein at least one of the base side area, the tip side area and the intermediate area is longer than the other areas in the axial direction of the second axis. 2. The robot according to claim 1, wherein the tip side area is longer than the base side area and the intermediate area in the axial direction of the second axis. 2. The robot according to claim 1, wherein the intermediate area is longer than the base side area and the tip side area in the axial direction of the second axis. The bottom portion and the side wall portion form a recess having an opening,
The robot according to any one of claims 1 to 3, wherein the cover covers the opening. a motor that moves the shaft in the axial direction of the third axis or drives the shaft around the axial direction of the third axis;
4. The robot according to claim 3, wherein the motor is arranged so as to overlap the intermediate area in a plan view of a plane including the second axis and the third axis. The robot according to claim 2, wherein the shaft is arranged so as to overlap with the tip side area in the plan view.

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