Robot and robot system

A robot includes: a first arm rotatable about a first rotation axis; a second arm provided on the first arm rotatably about a second rotation axis that is a different axial direction from an axial direction of the first rotation axis; and a moving part provided on the second arm rotatably about a third rotation axis. The moving part has a third arm and a fourth arm. A maximum length of the moving part is longer than a length of the second arm and shorter than twice the length of the second arm. The first arm has a length longer than the length of the second arm. The first arm and the second arm can overlap with each other, as viewed from the axial direction of the second rotation axis.

BACKGROUND

1. Technical Field

The present invention relates to a robot and a robot system.

2. Related Art

According to the related art, a robot having a robot arm is known. The robot arm has a plurality of arms (arm members) connected together via joint parts, and an end effector, for example, a hand, is installed on the arm on the most distal end side (most downstream side). The joint parts are driven by a motor. As the joint parts are driven, the arms rotate. The robot thus grasps an object with the hand, for example, then moves the object to a predetermined place, and carries out predetermined work such as assembly.

As such a robot, JP-A-2014-46401 discloses a vertical multi-joint robot. In the robot disclosed in JP-A-2014-46401, an operation of moving the hand to a position that is 180 degrees different about a first rotation axis, which is a rotation axis on the most proximal end side (most upstream side) (rotation axis extending in a vertical direction), in relation to the base, is carried out by rotating a first arm, which is an arm on the most proximal end side, about the first rotation axis in relation to the base.

The robot disclosed in JP-A-2014-46401 needs a large space to prevent interference of the robot when moving the hand to a position that is 180 degrees different about the first rotation axis in relation to the base.

SUMMARY

An advantage of some aspects of the invention is to provide a robot and a robot system in which an operation of moving the position of the distal end part of the robot to a position that is 180 degrees different about the first rotation axis can be achieved even when the space to prevent interference of the robot is small.

APPLICATION EXAMPLE 1

This application example of the invention is directed to a robot including: a first arm rotatable about a first rotation axis; a second arm provided on the first arm rotatably about a second rotation axis that is a different axial direction from an axial direction of the first rotation axis; and a moving part provided on the second arm rotatably about a third rotation axis. The moving part has a third arm and a fourth arm. A maximum length of the moving part is longer than a length of the second arm and shorter than twice the length of the second arm. The first arm has a length longer than the length of the second arm. The first arm and the second arm can overlap with each other, as viewed from the axial direction of the second rotation axis.

With this configuration, the space to prevent interference of the robot when moving the distal end of the second arm to a position that is 180 degrees different about the first rotation axis can be reduced.

Also, the distal end of the moving part can be prevented from interfering with the second arm.

APPLICATION EXAMPLE 2

In the robot according to the application example of the invention, it is preferable that the maximum length of the moving part is longer than 1.2 times the length of the second arm and shorter than 1.8 times the length of the second arm.

With this configuration, the distal end of the moving part can be prevented from interfering with the second arm.

APPLICATION EXAMPLE 3

In the robot according to the application example of the invention, it is preferable that the third arm is provided on the second arm rotatably about the third rotation axis, and that the fourth arm is provided on the third arm rotatably about a fourth rotation axis.

With this configuration, more complex operations can be carried out easily.

APPLICATION EXAMPLE 4

It is preferable that the robot according to the application example of the invention includes a fifth arm provided on the fourth arm rotatably about a fifth rotation axis, and a sixth arm provided on the fifth arm rotatably about a sixth rotation axis.

With this configuration, more complex operations can be carried out easily.

APPLICATION EXAMPLE 5

It is preferable that the robot according to the application example of the invention includes a first motor which rotates the first arm, a second motor which rotates the second arm, and a third motor which rotates the moving part, and that the second motor has a capacity equal to or above a capacity of the third motor and equal to or below twice the capacity of the third motor.

With this configuration, a reduction in size and weight of the robot can be achieved.

APPLICATION EXAMPLE 6

In the robot according to the application example of the invention, it is preferable that the capacity of the second motor is equal to or above the capacity of the third motor and equal to or below 1.5 times the capacity of the third motor.

With this configuration, a reduction in size and weight of the robot can be achieved.

APPLICATION EXAMPLE 7

In the robot according to the application example of the invention, it is preferable that the capacity of the second motor is equal to or above the capacity of the third motor and equal to or below 1.1 times the capacity of the third motor.

With this configuration, a reduction in size and weight of the robot can be achieved.

APPLICATION EXAMPLE 8

It is preferable that the robot according to the application example of the invention has a linear member including at least one of a wire and a pipe, and that the linear member has a U-shaped folding part arranged on an outer circumference of at least one of the first motor, the second motor and the third motor.

With this configuration, when the robot is driven, the linear member can be restrained from being twisted or fractured. Therefore, damage to the linear member can be restrained and durability can be improved.

APPLICATION EXAMPLE 9

In the robot according to the application example of the invention, it is preferable that a maximum lateral width of the first arm is equal to or greater than a maximum lateral width of the second arm and the moving part, as viewed from the axial direction of the second rotation axis.

With this configuration, the robot is compact when the first arm, the second arm and the moving part overlap with each other, as viewed from the axial direction of the second rotation axis. For example, installing the robot, carrying the robot, packing the robot and the like can be carried out easily.

APPLICATION EXAMPLE 10

In the robot according to the application example of the invention, it is preferable that a brake for braking the second arm and a brake for braking the moving part are provided, and that a brake for braking the first arm is not provided.

With this configuration, a reduction in size and weight and simplification of the structure of the robot can be achieved because of the absence of a brake for braking the first arm.

APPLICATION EXAMPLE 11

This application example of the invention is directed to a robot system including: a cell; and a robot provided in the cell. The robot includes: a first arm rotatable about a first rotation axis; a second arm provided on the first arm rotatably about a second rotation axis that is a different axial direction from an axial direction of the first rotation axis; and a moving part provided on the second arm rotatably about a third rotation axis. The moving part has a third arm and a fourth arm. A maximum length of the moving part is longer than a length of the second arm and shorter than twice the length of the second arm. The first arm has a length longer than the length of the second arm. The first arm and the second arm can overlap with each other, as viewed from the axial direction of the second rotation axis.

With this configuration, the space to prevent interference of the robot when moving the distal end of the second arm to a position that is 180 degrees different about the first rotation axis can be reduced. This enables miniaturization of the cell, and the installation space for installing the robot system can be reduced.

Also, the distal end of the moving part can be prevented from interfering with the second arm.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the robot system according to the invention will be described in detail on the basis of a preferred embodiment shown in the accompanying drawings.

FIG. 1is a perspective view showing an embodiment of the robot system according to the invention.FIG. 2is a perspective view showing a robot in the robot system shown inFIG. 1.FIG. 3is a schematic view showing the robot in the robot system shown inFIG. 1.FIG. 4shows the robot in a front view of the robot system shown inFIG. 1.FIGS. 5 and 6each show the robot in a side view of the robot system shown inFIG. 1. That is, the robot shown inFIGS. 5 and 6is the robot shown inFIG. 4as viewed from the right inFIG. 4.FIGS. 7A to 7Eexplain an operation when the robot in the robot system shown inFIG. 1carries out work.FIG. 8explains a linear member of the robot in the robot system shown inFIG. 1.

In the description below, as a matter of convenience of explanation, the top side inFIGS. 1, 4 to 7Eis referred to as “top” or “upper part”, and the bottom side is referred to as “bottom” or “lower part”. The base side inFIGS. 1 to 7Eis referred to as “proximal end” or “upstream”, and the opposite side (hand side) is referred to as “distal end” or “downstream”. The up-down direction inFIGS. 1, 4 to 7Eis the vertical direction. InFIG. 2, the robot is shown in the state of not being installed inside the cell. InFIG. 8, the linear member and each member near the folding part of the linear member are schematically shown.

A robot system100shown inFIG. 1has a robot cell50including a cell5and a robot (industrial robot)1provided inside the cell5. The robot1has a robot main body (main body part)10and a robot controller (control unit), not shown, for controlling the working of the robot main body10(robot1).

The robot system100can be used, for example, in a manufacturing process for manufacturing a precision device such as a wristwatch. The robot1can, for example, carry out work such as feeding, removing, carrying and assembling the precision device and components forming the precision device.

The robot controller may be arranged inside the cell5or may be arranged outside the cell5. If the robot controller is arranged inside the cell5, the robot controller may be included inside the robot main body10(robot1) or may be a separate unit from the robot main body10. The robot controller may be made up of, for example, a personal computer (PC) with a built-in central processing unit (CPU), or the like.

As shown inFIG. 1, the cell5is a member which surrounds (accommodates) the robot1, and can be easily relocated. Inside the cell5, the robot1mainly carries out work such as assembly.

The cell5has four foot parts54which allow the entirety of the cell5to be installed, for example, in an installation space such as a floor, a frame part51supported by the four foot parts54, a work table (table part)52provided in a lower part of the frame part51, and a ceiling part53provided in an upper part of the frame part51. The outer shape of the cell5, when viewed from the vertical direction, is square in this embodiment, though it is not particularly limited. The outer shape may also be rectangular or the like, for example.

The frame part51has four support posts511extending in the vertical direction (up-down direction inFIG. 1), and a frame-like top part513provided at the top end of the four support posts511.

The work table52, in this embodiment, is in the shape of a rectangular parallelepiped and has a quadrilateral (rectangular) plate on each of its six faces. The work table52has its four corners supported by the four support posts511of the frame part51, as viewed from the vertical direction. The robot1can carry out each type of work on a work surface521of the work table52.

The ceiling part53is a member which supports the robot1, and in this embodiment, is in the shape of a quadrilateral (rectangular) plate. The ceiling part53has its four corners supported by the four support posts511of the frame part51, as viewed from the vertical direction. A base11of the robot1, described later, is fixed (supported) on a ceiling surface (first surface)531on the bottom side of the ceiling part53. The ceiling surface531is a flat surface parallel to a horizontal plane.

Between the support posts511next to each other above the work table52, that is, on the four lateral sides of the frame part51and the top part513, a safety board (not shown) or the like may be installed in order to prevent the operator or foreign matters such as dust from entering into the frame part51.

The cell5need not necessarily have the foot parts54. In such a case, the work table52may be installed directly in the installation space.

Robot

As shown inFIGS. 2 to 4, the robot main body10has a base (support part)11and a robot arm6. The robot arm6includes a first arm (first arm member) (arm part)12, a second arm (second arm member) (arm part)13, a third arm (third arm member) (arm part)14, a fourth arm (fourth arm member) (arm part)15, a fifth arm (fifth arm member) (arm part)16and a sixth arm (sixth arm member) (arm part)17(six arms), and a first drive source401, a second drive source402, a third drive source403, a fourth drive source404, a fifth drive source405and a sixth drive source406(six drive sources). The fifth arm16and the sixth arm17form a wrist. At the distal end of the sixth arm17, for example, an end effector such as a hand91can be removably attached. Also, the third arm14and the fourth arm15form a moving part18.

The robot1is a vertical multi-joint (six-axis) robot in which the base11, the first arm12, the second arm13, the third arm14, the fourth arm15, the fifth arm16and the sixth arm17are connected in this order from the proximal end side toward the distal end side. Hereinafter, each of the first arm12, the second arm13, the third arm14, the fourth arm15, the fifth arm16and the sixth arm17is also referred to as the “arm”. Each of the first drive source401, the second drive source402, the third drive source403, the fourth drive source404, the fifth drive source405and the sixth drive source406is also referred to as the “drive source”.

As shown inFIGS. 1 and 4, the base11is a portion fixed (member attached) to the ceiling surface531of the ceiling part53of the cell5. The fixing method for this is not particularly limited. For example, a fixing method using a plurality of bolts or the like can be employed.

In this embodiment, a plate-like flange111provided at a distal end part of the base11is attached to the ceiling surface531. However, the site of the base11attached to the ceiling surface531is not limited to this example. For instance, a proximal end surface of the base11(en surface on the top side inFIG. 4) may be used.

Here, in this robot1, the connection part between the base11and the robot arm6, that is, the center of a bearing part62(seeFIG. 5), described later, is situated above the ceiling surface531in the vertical direction. The center of the bearing part62is not limited to this position and may be situated, for example, below the ceiling surface531in the vertical direction or may be situated at the same position as the ceiling surface531in the vertical direction.

In the robot1, since the base11is installed on the ceiling surface531, the connection part between the first arm12and the second arm13, that is, the center of a bearing part, not shown, for rotatably supporting the second arm13, is situated below the center of the bearing part62in the vertical direction.

The base11may or may not include a joint171, described later (seeFIG. 3).

The first arm12, the second arm13, the third arm14, the fourth arm15, the fifth arm16and the sixth arm17are supported in such a way that each of these arms can be independently displaced in relation to the base11.

As shown inFIGS. 2 to 4, the first arm12has a bent shape. In the state shown inFIG. 4, the first arm12has: a first part121connected to the base11and extending downward inFIG. 4in the axial direction of a first rotation axis O1(vertical direction), described later, from the base11; a second part122extending to the left inFIG. 4in the axial direction of a second rotation axis O2(horizontal direction) from the bottom end of the first part121inFIG. 4; a third part123provided at the end of the second part122opposite to the first part121and extending downward inFIG. 4in the axial direction of the first rotation axis O1(vertical direction); and a fourth part124extending to the right inFIG. 4in the axial direction of the second rotation axis O2(horizontal direction) from the end of the third part123opposite to the second part122. The first part121, the second part122, the third part123and the fourth part124are integrally formed. The second part122and the third part123are substantially orthogonal to (intersecting with) each other, as viewed from the direction orthogonal to both the first rotation axis O1and the second rotation axis O2(as viewed from the front of the sheet ofFIG. 4).

The second arm13has a longitudinal shape and is connected to a distal end part of the first arm12, that is, the end of the fourth part124opposite to the third part123.

The third arm14has a longitudinal shape and is connected to a distal end part of the second arm13, that is, the end of the second arm13opposite to its end connected to the first arm12.

The fourth arm15is connected to a distal end part of the third arm14, that is, the end of the third arm14opposite to its end connected to the second arm13. The fourth arm15has a pair of support parts151,152facing each other. The support parts151,152are used to connect the fourth arm15to the fifth arm16.

The fifth arm16is situated between and connected to the support parts151,152and thus connected to the fourth arm15. The fourth arm15is not limited to this structure and may have, for example, one support part (cantilever).

The sixth arm17is in the shape of a flat plate and is connected to a proximal end part of the fifth arm16. At a distal end part of the sixth arm17(end opposite to the fifth arm16), the hand91to grasp, for example, a precision device such as a wristwatch, or a component or the like, is removably installed as an end effector. The driving of the hand91is controlled by the robot controller. The hand91is not particularly limited and may be, for example, a structure having a plurality of finger parts (fingers). By controlling the operations of the arms12to17and the like while causing the hand91to grasp a precision device, component or the like, the robot1can carry out each type of work such as carrying the precision device or component.

As shown inFIGS. 2 to 4, the base11and the first arm12are connected together via the joint171. The joint171has a mechanism for supporting the first arm12connected to the base11, rotatably in relation to the base11. This enables the first arm12to rotate about the first rotation axis O1(around the first rotation axis O1) parallel to the vertical direction, in relation to the base11. The first rotation axis O1coincides with a normal line to the ceiling surface531of the ceiling part53to which the base11is attached. The first rotation axis O1is a rotation axis situated on the most upstream side of the robot1. The rotation around the first rotation axis O1is carried out by the driving of the first drive source401having a motor (first motor)401M and a decelerator (not shown). The first drive source401is driven by the motor401M and a cable (not shown). The motor401M is controlled by the robot controller via a motor driver301electrically connected to the motor401M. The decelerator may be omitted.

For the first arm12, a brake (braking device) for braking the first arm12is not provided. Therefore, a reduction in size and weight and simplification of the structure of the robot1can be achieved.

The first arm12and the second arm13are connected together via a joint172. The joint172has a mechanism for supporting one of the first arm12and the second arm13connected to each other, rotatably in relation to the other. This enables the second arm13to rotate about the second rotation axis O2(around the second rotation axis O2) parallel to the horizontal direction, in relation to the first arm12. The second rotation axis O2is orthogonal to the first rotation axis O1. The rotation around the second rotation axis O2is carried out by the driving of the second drive source402having a motor (second motor)402M and a decelerator (not shown). The second drive source402is driven by the motor402M and a cable (not shown). The motor402M is controlled by the robot controller via a motor driver302electrically connected to the motor402M. The decelerator may be omitted.

As a brake (braking device) for braking the second arm13, a brake (not shown) is provided near the axis part of the motor402M. This brake can prevent the axis part of the motor402M from rotating and thus enables the attitude of the second arm13to be held.

The second rotation axis O2may be parallel to an axis orthogonal to the first rotation axis O1. Alternatively, the second rotation axis O2may have a different axial direction from the first rotation axis O1, even if it is not orthogonal to the first rotation axis O1.

The second arm13and the third arm14are connected together via a joint173. The joint173has a mechanism for supporting one of the second arm13and the third arm14connected to each other, rotatably in relation to the other. This enables the third arm14to rotate about a third rotation axis O3(around the third rotation axis O3) parallel to the horizontal direction, in relation to the second arm13. The third rotation axis O3is parallel to the second rotation axis O2. The rotation around the third rotation axis O3is carried out by the driving of the third drive source403having a motor (third motor)403M and a decelerator (not shown). The third drive source403is driven by the motor403M and a cable (not shown). The motor403M is controlled by the robot controller via a motor driver303electrically connected to the motor403M. The decelerator may be omitted.

As a brake (braking device) for braking the third arm14, a brake (not shown) is provided near the axis part of the motor403M. This brake can prevent the axis part of the motor403M from rotating and thus enables the attitude of the third arm14to be held.

The third arm14and the fourth arm15are connected together via a joint174. The joint174has a mechanism for supporting one of the third arm14and the fourth arm15connected to each other, rotatably in relation to the other. This enables the fourth arm15to rotate about a fourth rotation axis O4(around the fourth rotation axis O4) parallel to the direction of the center axis of the third arm14, in relation to the third arm14(base11). The fourth rotation axis O4is orthogonal to the third rotation axis O3. The rotation around the fourth rotation axis O4is carried out by the driving of the fourth drive source404having a motor (fourth motor)404M and a decelerator (not shown). The fourth drive source404is driven by the motor404M and a cable (not shown). The motor404M is controlled by the robot controller via a motor driver304electrically connected to the motor404M. The decelerator may be omitted.

As a brake (braking device) for braking the fourth arm15, a brake (not shown) is provided near the axis part of the motor404M. This brake can prevent the axis part of the motor404M from rotating and thus enables the attitude of the fourth arm15to be held.

The fourth rotation axis O4may be parallel to an axis orthogonal to the third rotation axis O3. Alternatively, the fourth rotation axis O4may have a different axial direction from the third rotation axis O3, even if it is not orthogonal to the third rotation axis O3.

The fourth arm15and the fifth arm16are connected together via a joint175. The joint175has a mechanism for supporting one of the fourth arm15and the fifth arm16connected to each other, rotatably in relation to the other. This enables the fifth arm16to rotate about a fifth rotation axis O5(around the fifth rotation axis O5) orthogonal to the direction of the center axis of the fourth arm15, in relation to the fourth arm15. The fifth rotation axis O5is orthogonal to the fourth rotation axis O4. The rotation around the fifth rotation axis O5is carried out by the driving of the fifth drive source405. The fifth drive source405has a motor (fifth motor)405M, a decelerator (not shown), a first pulley (not shown) connected to the axis part of the motor405M, a second pulley (not shown) spaced apart from the first pulley and connected to the axis part of the decelerator, and a belt (not shown) laid over the first pulley and the second pulley. The fifth drive source405is driven by the motor405M and a cable (not shown). The motor405M is controlled by the robot controller via a motor driver305electrically connected to the motor405M. The decelerator may be omitted.

As a brake (braking device) for braking the fifth arm16, a brake (not shown) is provided near the axis part of the motor405M. This brake can prevent the axis part of the motor405M from rotating and thus enables the attitude of the fifth arm16to be held.

The fifth rotation axis O5may be parallel to an axis orthogonal to the fourth rotation axis O4. Alternatively, the fifth rotation axis O5may have a different axial direction from the fourth rotation axis O4, even if it is not orthogonal to the fourth rotation axis O4.

The fifth arm16and the sixth arm17are connected together via a joint176. The joint176has a mechanism for supporting one of the fifth arm16and the sixth arm17connected to each other, rotatably in relation to the other. This enables the sixth arm17to rotate about a sixth rotation axis O6(around the sixth rotation axis O6) in relation to the fifth arm16. The sixth rotation axis O6is orthogonal to the fifth rotation axis O5. The rotation around the sixth rotation axis O6is carried out by the driving of the sixth drive source406having a motor (sixth motor)406M and a decelerator (not shown). The sixth drive source406is driven by the motor406M and a cable (not shown). The motor406M is controlled by the robot controller via a motor driver306electrically connected to the motor406M. The decelerator may be omitted.

As a brake (braking device) for braking the sixth arm17, a brake (not shown) is provided near the axis part of the motor406M. This brake can prevent the axis part of the motor406M from rotating and thus enables the attitude of the sixth arm17to be held.

The sixth rotation axis O6may be parallel to an axis orthogonal to the fifth rotation axis O5. Alternatively, the sixth rotation axis O6may have a different axial direction from the fifth rotation axis O5, even if it is not orthogonal to the fifth rotation axis O5.

The motors401M to406M are not particularly limited and may be, for example, servo motors such as AC servo motors or DC servo motors, and the like.

The respective brakes are not particularly limited and may be, for example, electromagnetic brakes, and the like.

For the first arm12, similarly to the other arms, a brake (not shown) such as an electromagnetic brake, for example, may be provided near the axis part of the motor401M as a brake for braking the first arm12.

The motor drivers301to306are arranged on the base in the illustrated configuration. However, this configuration is not limiting and the motor drivers301to306may be arranged, for example, in the robot controller.

As shown inFIG. 8, the robot1also has a linear member20including at least one of a wire and a pipe. The wire may be, for example, an electrical wire or the like. The pipe may be, for example, a tube (tubular member) through which a fluid such as air (gas) or water (liquid) flows. In this embodiment, the case where the linear member20is a wire will be described as an example.

The linear member20has a folding part (not shown) arranged on the outer circumference of the motor401M, a folding part21arranged on the outer circumference of the motor402M, and a folding part (not shown) arranged on the outer circumference of the motor403M. The configurations of the respective folding parts and their vicinities are similar to one another and therefore the folding part arranged on the outer circumference of the motor402M is described below as a representative example.

As shown inFIG. 8, the folding part21is U-shaped, that is, bent into a U-shape. One end part211of the folding part21is fixed, with a clamp441, to the outer circumferential surface of a rotating member43of the decelerator which is rotatable in relation to the motor402M. The other end part212is fixed to the outer circumferential surface of the motor402M with a clamp442. The rotating member43is fixed to the first arm12. The motor402M is fixed to the second arm13.

When the motor402M is driven and the second arm13rotates, the rotating member43rotates in relation to the motor402M. In this case, the torsion in the folding part21is restrained and the folding part21undergoes bending deformation. Thus, the stress acting on the linear member20is relaxed. That is, a large bend radius of the linear member20can be secured at the folding part21, and the linear member20can be restrained from being twisted or fractured when the second arm13rotates. Thus, damage to the linear member20can be restrained and durability can be improved.

Up to this point, the configuration of the robot1has been briefly described.

Next, the relations between the first arm12to the sixth arm17will be described, with different expressions and from various perspectives. The third arm14to the sixth arm17are considered to be in a straightened state, that is, in their longest states. In other words, these arms are considered to be in the state where the fourth rotation axis O4and the sixth rotation axis O6coincide with each other or parallel to each other.

First, as shown inFIG. 5, the length L1of the first arm12is set to be longer than the length L2of the second arm13.

Here, the length L1of the first arm12is the distance between the second rotation axis O2and a centerline621extending in a left-right direction inFIG. 5of the bearing part62rotatably supporting the first arm12, as viewed from the axial direction of the second rotation axis O2.

The length L2of the second arm13is the distance between the second rotation axis O2and the third rotation axis O3, as viewed from the axial direction of the second rotation axis O2.

Also, the first arm12and the second arm13are configured in such a way that the angle θ formed by the first arm12and the second arm13can be made 0 degrees, as viewed from the axial direction of the second rotation axis O2, as shown inFIG. 6. That is, the first arm12and the second arm13are configured in such a way as to be able to overlap with each other, as viewed from the axial direction of the second rotation axis O2.

The second arm13is configured in such a way as not to interfere with the ceiling surface531of the ceiling part53where the base11is provided and the second part122of the first arm12, when the angle θ is 0 degrees, that is, when the first arm12and the second arm13overlap with each other, as viewed from the axial direction of the second rotation axis O2. In the case where the proximal end surface of the base11is attached to the ceiling surface531, the second arm13is similarly configured in such a way as not to interfere with the ceiling surface531and the second part122of the first arm12.

Here, the angle θ formed by the first arm12and the second arm13is the angle formed by a straight line passing through the second rotation axis O2and the third rotation axis O3(center axis of the second arm13as viewed from the axial direction of the second rotation axis O2)61and the first rotation axis O1, as viewed from the axial direction of the second rotation axis O2.

By rotating the second arm13without rotating the first arm.12, it is possible to move the distal end of the second arm13to a position that is 180 degrees different around the first rotation axis O1, following the state where the angle θ is 0 degrees as viewed from the axial direction of the second rotation axis O2(state where the first arm12and the second arm13overlap with each other) (seeFIGS. 7A to 7E). That is, by rotating the second arm13without rotating the first arm12, it is possible to move the distal end of the robot arm6(distal end of the sixth arm17) from a first position shown inFIG. 7Ato the state where the angle θ is 0 degrees, and then to a second position shown inFIG. 7Ethat is 180 degrees different around the first rotation axis O1(seeFIGS. 7A to 7E). The third arm14to the sixth arm17are each rotated according to need.

When the distal end of the second arm13is moved to a position that is 180 degrees different around the first rotation axis O1(when the distal end of the robot arm6is moved from the first position to the second position), the distal end of the second arm13and the distal end of the robot arm6move on a straight line, as viewed from the axial direction of the first rotation axis O1.

The total length (maximum length) L3of the third arm14to the sixth arm17is set to be longer than the length L2of the second arm13.

Thus, when the second arm13and the third arm14overlap with each other, as viewed from the axial direction of the second rotation axis O2, the distal end of the sixth arm17can be made to protrude from the second arm13. Thus, the hand91can be prevented from interfering with the first arm12and the second arm13.

Here, the total length (maximum length) L3of the third arm14to the sixth arm17is the distance between the third rotation axis O3and the distal end of the sixth arm17, as viewed from the axial direction of the second rotation axis O2(seeFIG. 5). In this case, the third arm14to the sixth arm17are in the state where the fourth rotation axis O4and the sixth rotation axis O6coincide with each other or parallel to each other, as shown inFIG. 5.

The second arm13and the third arm14are configured in such a way as to be able to overlap with each other, as viewed from the axial direction of the second rotation axis O2, as shown inFIG. 6.

That is, the first arm12, the second arm13and the third arm14are configured in such a way as to be able to overlap with each other simultaneously, as viewed from the axial direction of the second rotation axis O2.

When the above relations are satisfied, by rotating the second arm13and the third arm14without rotating the first arm12, the robot1can move the hand91(distal end of the sixth arm17) to a position that is 180 degrees different around the first rotation axis O1, following the state where the angle θ formed by the first arm12and the second arm13is 0 degrees as viewed from the axial direction of the second rotation axis O2(state where the first arm12and the second arm13overlap with each other). Using this operation, the robot1can be driven efficiently, and the space provided to prevent interference of the robot1can be reduced. Also, various advantages can be achieved as follows.

The total length (maximum length) L4of the third arm14and the fourth arm15is set to be longer than the length L2of the second arm13and shorter than twice the length L2of the second arm13. Preferably, the total length L4may be set to be longer than 1.2 times the length L2of the second arm13and shorter than 1.8 times the length L2of the second arm13, and more preferably longer than 1.4 times the length L2of the second arm13and shorter than 1.8 times the length L2of the second arm13. It is preferable that L4is set, for example, to 1.7 times L2.

Thus, when the second arm13and the third arm14overlap with each other, as viewed from the axial direction of the second rotation axis O2, the fourth arm15can be made to protrude from the second arm13. Therefore, the hand91, the sixth arm17and the fifth arm16can be prevented from interfering with the first arm12and the second arm13.

If L4is equal to or shorter than L2, there is a risk that the hand91, the sixth arm17and the fifth arm16may interfere with the first arm12and the second arm13when the second arm13and the third arm14overlap with each other, as viewed from the axial direction of the second rotation axis O2.

If L4is equal to or longer than twice L2, the robot1increases in size and the height L of the cell (seeFIG. 1) increases, raising the ceiling part53. Therefore, the position of the center of gravity of the robot1becomes higher and the influence of vibration of the robot1increases. That is, there is an increase in vibration generated by a reactive force due to the operation of the robot1.

Here, the total length (maximum length) L4of the third arm14and the fourth arm15is the distance between the third rotation axis O3and the fifth rotation axis O5, as viewed from the axial direction of the second rotation axis O2(axial direction of the third rotation axis) (seeFIG. 4).

If the above conditions are satisfied, L2is not particularly limited and may be suitably set according to various conditions. However, preferably L2may be 50 mm or longer and 600 mm or shorter, and more preferably 100 mm or longer and 200 mm or shorter. It is preferable that L2is set, for example, to 150 mm.

If the above conditions are satisfied, L4is not particularly limited and may be suitably set according to various conditions. However, preferably L4may be 100 mm or longer and 500 mm or shorter, and more preferably 200 mm or longer and 300 mm or shorter. It is preferable that L4is set, for example, to 259 mm.

The total length (wrist length) L5of the fifth arm16and the sixth arm17is not particularly limited and may be suitably set according to various conditions. However, preferably L5may be 20 mm or longer and 100 mm or shorter, and more preferably 40 mm or longer and 70 mm or shorter. It is preferable that L5is set, for example, to 55 mm.

Here, the total length (wrist length) L5of the fifth arm16and the sixth arm17is the distance between the fifth rotation axis O5and the distal end of the sixth arm17, as viewed from the axial direction of the fifth rotation axis O5(seeFIG. 4).

The length L6between the first rotation axis O1and the farthest part of the first arm12from the first rotation axis O1in the axial direction of the second rotation axis O2is not particularly limited and may be suitably set according to various conditions. However, it is preferable that L6is shorter than half the width W of the cell5(seeFIG. 1). Therefore, when the robot1is driven, the robot1can be prevented from contacting the cell5or from protruding out of the cell5by accident.

Specifically, L6may be preferably 375 mm or shorter, and more preferably 325 mm or shorter. Even more preferably, L6may be 275 mm or shorter. Also, it is preferable that L6is 40 mm or longer.

It is preferable that the maximum lateral width W1max of the first arm12is equal to or greater than the maximum lateral width W2max of the other arms, that is, the second arm13to the sixth arm17, as viewed from the axial direction of the second rotation axis O2. Thus, the robot1is compact when the first arm12, the second arm13and the third arm14overlap with each other, as viewed from the axial direction of the second rotation axis O2. For example, installing the robot1, carrying the robot1, packing the robot1and the like can be carried out easily.

It is preferable that the rotatable range of the first arm12around the first rotation axis O1, the rotatable range of the second arm13around the second rotation axis O2, the rotatable range of the third arm14around the third rotation axis O3, and the rotatable range of the fourth arm15around the fourth rotation axis O4are each −180 degrees or greater and 180 degrees or smaller.

It is preferable that the rotatable range of the fifth arm16around the fifth rotation axis O5is −140 degrees or greater and 140 degrees or smaller.

It is preferable that the rotatable range of the sixth arm17around the sixth rotation axis O6is −360 degrees or greater and 360 degrees or smaller.

The relations between the capacities of the motors401M to406M are not particularly limited and may be suitably set according to various conditions. However, the capacity of the motor402M may be preferably equal to or greater than the capacity of the motor403M and equal to or smaller than twice the capacity of the motor403M, and more preferably equal to or greater than the capacity of the motor403M and equal to or smaller than 1.5 times the capacity of the motor403M, and even more preferably equal to or greater than the capacity of the motor403M and equal to or smaller than 1.1 times the capacity of the motor403M. It is preferable that the capacity of the motor402M is, for example, the same as the capacity of the motor403M.

The robot1often takes attitudes where the moment of the structure from the second arm13to the sixth arm17(hand91) and the moment of the structure from the third arm14to the sixth arm17(hand91) are close to each other. Therefore, there is no problem if the capacity of the motor402M is the same or close to the capacity of the motor403M. Therefore, by setting the capacity of the motor402M as described above, a reduction in size and weight of the robot1can be achieved.

The capacity of the motor401M may be preferably equal to or greater than the capacity of the motor402M and equal to or smaller than twice the capacity of the motor402M, and more preferably equal to or greater than the capacity of the motor402M and equal to or smaller than 1.5 times the capacity of the motor402M, and even more preferably equal to or greater than the capacity of the motor402M and equal to or smaller than 1.1 times the capacity of the motor402M. It is preferable that the capacity of the motor401M is, for example, the same as the capacity of the motor402M. Thus, a reduction in size and weight of the robot1can be achieved.

The capacity of each of the motors401M to403M is not particularly limited and may be suitably set according to various conditions. However, the capacity of each of these motors may be preferably 50 W or greater and 200 W or smaller, and more preferably 80 W or greater and 120 W or smaller. It is preferable that the capacity of each of the motors401M to403M is set, for example, to 100 W.

The capacity of each of the motors404M and405M is not particularly limited and may be suitably set according to various conditions. However, the capacity of each of these motors may be preferably 10 W or greater and 60 W or smaller, and more preferably 20 W or greater and 40 W or smaller. It is preferable that the capacity of each of the motors404M and405M is set, for example, to 30 W.

The capacity of the motor406M is not particularly limited and may be suitably set according to various conditions. However, the capacity of the motor406M may be preferably 5 W or greater and 30 W or smaller, and more preferably 10 W or greater and 20 W or smaller. It is preferable that the capacity of the motor406M is set, for example, to 15 W.

The relations between deceleration ratios of the respective decelerators are not particularly limited and may be suitably set according to various conditions. However, it is preferable that the deceleration ratio of the decelerator of the third arm14is set to be higher than the deceleration ratio of the decelerator of the second arm13.

The rotation angle of the third arm14within expected operations of the robot1is often greater than the rotation angle of the second arm13. Therefore, by setting the deceleration ratios as described above, takt time can be reduced and productivity can be improved.

The deceleration ratios of the respective decelerators are not particularly limited and may be suitably set according to various conditions. However, it is preferable that the deceleration ratios of the decelerators of the first arm12and the second arm13are each set, for example, to 121. It is also preferable that the deceleration ratios of the decelerators of the third arm14and the fourth arm15are each set, for example, to 101. It is also preferable that the deceleration ratios of the decelerators of the fifth arm16and the sixth arm17are each set, for example, to 100.

Since the robot1has the configuration as described above, the installation space for the robot1, that is, the cell5, can be made smaller than in the related-art technique. Therefore, the area of the installation space (installation area) for installing the cell5, that is, an area S of the cell5when the cell5is viewed from the vertical direction, can be made smaller than in the related-art technique. Specifically, the area S can be reduced, for example, to 64% of the area in the related-art technique or smaller. Therefore, the width (length of one side in the horizontal direction) W of the cell5can be made smaller than the width in the related-art technique, and specifically, for example, 80% of the width in the related-art technique or less. As described above, in the embodiment, the cell5is square when viewed from the vertical direction and therefore the width (depth) W of the cell5in the longitudinal direction inFIG. 1and the width (lateral width) W of the cell5in the lateral direction inFIG. 1are the same. However, these widths may be different from each other. In such a case, one or both widths W can be reduced, for example, to 80% of the width in the related-art technique or less.

The area S, specifically, may be preferably smaller than 637500 mm2, and more preferably 500000 mm2or smaller, and even more preferably 400000 mm2or smaller. It is particularly preferable that the area S is 360000 mm2or smaller. With such an area S, the robot1can be prevented from interfering with the cell5when moving the distal end of the second arm13to a position that is 180 degrees different around the second rotation axis O2. Therefore, miniaturization of the cell5can be achieved and the installation space for installing the robot system100can be reduced. Thus, when a plurality of robot cells50is arranged to form a production line, the length of the production line can be restrained from becoming long.

Particularly the area S of 400000 mm2or smaller is substantially equal to or smaller than the size of the work area where a human works. Therefore, when the area S is 400000 mm2or smaller, for example, the human and the robot cell50can be easily replaced with each other. By replacing the human and the robot cell50with each other, the production line can be altered. Also, it is preferable that the area S is 10000 mm2or greater. This enables easy maintenance inside the robot cell50.

The width W, specifically, may be preferably less than 850 mm, and more preferably less than 750 mm, and even more preferably 650 mm or less. Thus, effects similar to the above effects can be achieved sufficiently. The width W is the average width of the cell5(average width of the frame part51). Also, it is preferable that the width W is 100 mm or more. This enables easy maintenance inside the robot cell50.

Since the robot1has the configuration as described above, the height (length in the vertical direction) L of the cell5can be made lower than the height in the related-art technique. Specifically, the height L can be reduced, for example, to 80% of the height in the related-art technique or below.

The height L, specifically, may be preferably 1700 mm or below, and more preferably 1000 mm or above and 1650 mm or below. When the height L is the upper limit value or below, the influence of vibration generated when the robot1operates in the cell5can be restrained further. The height L is the average height of the cell5including the foot parts54.

As described above, in the robot system100, by rotating the second arm13and the third arm14or the like without rotating the first arm12, the robot1can move the hand91(distal end of the robot arm6) to a position that is 180 degrees different around the first rotation axis O1, following the state where the angle θ formed by the first arm12and the second arm13is 0 degrees as viewed from the axial direction of the second rotation axis O2(state where the first arm12and the second arm13overlap with each other). Therefore, the space to prevent interference of the robot1can be reduced. This enables miniaturization of the cell5and a reduction in the installation space for installing the robot system100. Thus, for example, many robot systems100per unit length can be arranged along a production line, and the production line can be shortened.

Since the space to prevent interference of the robot1can be reduced, the ceiling part53can be lowered. Thus, the position of the center of gravity of the robot1becomes lower and the influence of vibration of the robot1can be reduced. That is, vibration generated by a reactive force due to the operation of the robot1can be restrained.

Also, the movement of the robot1can be reduced when moving the hand91. For example, it is possible not to rotate the first arm12or to reduce the rotation angle of the first arm12, and this enables a reduction in takt time and improvement in work efficiency.

In the robot1, a maximum payload of 2.5 kg or above (for example, 2.5 kg) can be achieved and a cycle time (of moving 1 kg/300 mm in horizontal direction and 25 mm in the vertical direction) of 0.9 seconds or below (for example, 0.9 seconds) can be achieved.

If the operation of moving the hand91(distal end of the robot arm6) of the robot1to a position that is 180 degrees different around the first rotation axis O1(hereinafter also referred to as “shortcut motion”) is executed simply by rotating the first arm12around the first rotation axis O1as in the related-art robot, there is a risk that the robot1may interfere with the cell5and peripheral devices, and therefore retreat points to avoid the interference need to be suggested to the robot1. For example, when the robot1interferes with the safety board (not shown) of the cell5if only the first arm12is rotated 90 degrees around the first rotation axis O1, a retreat point needs to be suggested to the robot1so as not to interfere with the safety board by rotating other arms. Similarly, when the robot1interferes with a peripheral device, another retreat point needs to be suggested to the robot1so as not to interfere with the peripheral device. In this way, with the related-art robot, multiple retreat points need to be suggested. Particularly in the case of a small-sized cell, a massive number of retreat points are needed and it takes a long time and much effort to suggest these retreat points.

In contrast, in the robot1, when executing the shortcut motion, there are very few areas and parts with the risk of interference. Therefore, the number of retreat points to be suggested can be reduced and the time and effort required for the suggestions can be reduced. That is, in the robot1, the number of retreat points to be suggested is, for example, approximately one third of that in the related-art robot and the suggestions are considerably easier.

An area (part)101surrounded by double-dotted chain lines on the right side ofFIG. 4, of the third arm14and the fourth arm15, is an area (part) where the robot1does not interfere or does not easily interfere with the robot1itself or other members. Therefore, when a predetermined member is installed in the area101, the member does not easily interfere with the robot1and peripheral devices or the like. Therefore, in the robot1, a predetermined member can be installed in the area101. Particularly, when the predetermined member is installed in the area on the right side ofFIG. 4of the third arm14, of the area101, the probability of the member interfering with peripheral devices (not shown) arranged on the work table52drops further, which is more effective.

The device that can be installed in the area101may be, for example, a controller for controlling driving of a sensor of a hand, hand-eye camera or the like, or an electromagnetic valve of an attraction mechanism, or the like.

As a specific example, when an attraction mechanism is to be provided on a hand, for example, if an electromagnetic valve or the like is installed in the area101, the electromagnetic valve does not obstruct the driving of the robot1. In this way, the area101is highly convenient.

The robot and the robot system according to the invention have been described above on the basis of the illustrated embodiment. However, the invention is not limited to the embodiment. The configuration of each part can be replaced with an arbitrary configuration with similar functions. Also, another arbitrary configuration may be added.

In the embodiment, the site where the base of the robot is fixed is the ceiling part of the cell. However, the invention is not limited to this. The wall part of the cell, the work table, the floor part and the like may also be employed.

In the embodiment, the robot is installed inside the cell. However, the invention is not limited to this. For example, the cell may be omitted. In this case, the site where the base is fixed may be, for example, the ceiling, the wall, the work table, the floor, the ground or the like in the installation space.

In the embodiment, the first surface, which is the surface (plane) where the robot (base) is fixed, is a surface (plane) parallel to the horizontal plane. However, the invention is not limited to this. For example, a surface (plane) tilted in relation to a horizontal plane or a vertical plane may be employed, and a surface (plane) parallel to a vertical plane may be employed as well. That is, the first rotation axis may be tilted in relation to the vertical direction or the horizontal direction and may be parallel to the horizontal direction.

While the number of rotation axes in the robot arm in the embodiment is six, the invention is not limited to this. The number of rotation axes in the robot arm may be, for example, two, three, four, five, or seven or more. That is, while the number of arms (links) in the embodiment is six, the invention is not limited to this. The number of arms may be, for example, two, three, four, five, or seven or more. In this case, for example, in the robot in the embodiment, an arm may be added between the second arm and the third arm, thus achieving a robot in which the number of arms is seven.

While the number of robot arms in the embodiment is one, the invention is not limited to this. The number of robot arms may be, for example, two or more. That is, the robot (robot main body) may be, for example, a multi-arm robot such as a dual-arm robot.

According to the invention, the robot (robot main body) may be a different form of robot. As a specific example, a legged walking (running) robot having a leg part or the like may be employed.

Also, according to the invention, a linear member such as a wire or pipe may be passed through at least a part of the inside of the drive source, for example, the inside of the decelerator and the inside of the motor.

The entire disclosure of Japanese Patent Application No. 2015-090068, filed Apr. 27, 2015 is expressly incorporated by reference herein.