JP2012121135A - Wrist mechanism of industrial robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose a wrist mechanism which is simple, serviceable, and highly reliable.SOLUTION: The wrist mechanism includes: a first motor 21 and a first reduction gear 23 for rotating a first movable part 24 by a wrist rotary shaft R extending along an upper arm 14; a second motor 25 fixed to the first movable part 24 and removable from the side of the wrist mechanism; a second reduction gear 26 which is in line with the second motor along the wrist rotary shaft R and fixed removably from the side of the wrist mechanism removable, and to which the rotation of an output shaft of the second motor is input; a second movable part 27 to be rotated by the second reduction gear on a wrist warped axis B orthogonal to the wrist rotary shaft R; and a third motor 28 and a third reduction gear 29 fixed to the second movable part, rotating a third movable part on a wrist rotary shaft T.

Description

  The present invention relates to a wrist mechanism provided at the arm tip of an industrial robot, and particularly to a wrist mechanism having three degrees of freedom.

Conventionally, vertical articulated robots having a total of six degrees of freedom have been widely used as industrial robots. The wrist part of this type of industrial robot has three axes out of six degrees of freedom. As a mechanism for driving these three wrist parts, the wrist part three axes are driven at the rear end of the upper arm. A rotary motor is arranged for three axes (for example, Patent Document 1 and Patent Document 2).
In the robots of Patent Documents 1 and 2, the rotational driving force of the rotary motor disposed at the rear end of the upper arm is transmitted to the wrist at the tip of the upper arm. These three rotary drive shafts are supported so that they can rotate respectively. That is, the three rotation drive shafts are inserted into the cylindrical first rotation drive shaft, and the second rotation drive shaft formed in a cylindrical shape is inserted into the first rotation drive shaft. The third rotation drive shaft is inserted into the inside.
Japanese Utility Model Laid-Open No. 5-16184 JP-A-2-41888

As described above, the mechanism for driving the wrist portion of the conventional industrial robot transmits the driving force from the rotary motor disposed at the rear end of the upper arm to the wrist portion provided at the tip of the upper arm. Since a rotary drive shaft, bearings for supporting these rotary drive shafts, and a large number of gears are required, the number of parts is increased, the structure is complicated, and the reliability of the robot is lowered. . In addition, since the number of parts increases, there is a problem that the manufacturing cost becomes expensive.
In order to solve such problems, the present invention aims to simplify the wrist mechanism and reduce the number of parts, and to disclose a wrist mechanism that is easy to maintain and highly reliable. Objective.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a wrist mechanism of an industrial robot provided at the tip of the upper arm and having a total degree of freedom of three axes, wherein the wrist mechanism is fixed to the upper arm, and the wrist is along the upper arm. A first motor and a first speed reducer that rotate the first movable part around the turning axis R; an output shaft that is fixed to the first movable part so as to be removable from a side surface of the wrist mechanism and is orthogonal to the wrist turning axis R Are arranged along the wrist turning axis R together with the second motor, fixed to the first movable part so as to be removable from a side surface of the wrist mechanism, and arranged on the output shaft of the second motor. A second speed reducer to which rotation is input, a second movable part that is fixed to the output shaft of the second speed reducer and rotates on a wrist bending axis B orthogonal to the wrist turning axis R, and the second movable part. The wrist bending axis B is fixed A wrist mechanism for an industrial robot, comprising: a third motor and a third speed reducer that rotate the third movable portion with a wrist rotation axis T orthogonal to the first rotation axis.
The invention according to claim 2 is characterized in that the first movable part is formed in a cylindrical shape, and the tip end side of the cylinder opens toward the third motor. It is a robot wrist mechanism.
According to a third aspect of the present invention, the wrist mechanism according to the first or second aspect, a lower arm that supports the upper arm so as to swing up and down, and a swivel head that supports the lower arm so as to swing back and forth. And a base that supports the swivel head so as to be able to swivel about a vertical axis.
According to a fourth aspect of the present invention, there is provided the wrist mechanism according to the first or second aspect, an upper lower arm that supports the upper arm so as to swing up and down, and a lower lower portion that rotatably supports the upper lower arm. A total of seven-axis industry, comprising: an arm; a swivel head that supports the lower lower arm so as to be swingable back and forth; and a base that supports the swivel head so as to be pivotable about a vertical axis. Robot.

  According to the present invention, the number of parts in the wrist is greatly reduced, and the manufacturing cost can be reduced. By reducing the number of parts, the wrist mechanism is simplified and the reliability can be improved. In addition, the motor and the speed reducer can be easily replaced, and can be recovered in a short period of time when a failure occurs.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1A and 1B are side views showing an industrial robot to which the wrist mechanism of the present invention is applied. The base 11 is an installation part of a robot installed on a floor of a factory or the like (not shown). A turn head 12 is supported on the base 11 so as to be turnable. The turning head 12 can turn around a vertical turning axis S. The lower end of the lower arm 13 is swingably supported by the turning head 12. The lower arm 13 is swingable about a horizontal longitudinal axis L that is perpendicular to the pivot axis S. A base end of the upper arm 14 is swingably supported on the upper end of the lower arm 13. The upper arm 14 can swing around a swing axis U parallel to the front-rear axis L. A wrist mechanism 15 is provided on the distal end side of the upper arm 14. As will be described later, the wrist mechanism 15 is a mechanism having a degree of freedom of three axes. An end effector (not shown) is connected to the distal end of the wrist mechanism 15. The robot then positions the end effector at a desired position while rotating each of the six axes in total, and performs a predetermined workpiece operation.
As shown in FIG. 1B, the lower arm 13 is divided into an upper side and a lower side, and a single-axis movable shaft is further provided at the divided part, so that the wrist mechanism of the present invention is applied to a total of seven axes of robots. Sometimes. In the figure, the movable shaft is provided in the extending direction of the lower arm 13.

FIG. 2 shows the wrist mechanism 15 according to the first embodiment. (A) is an external view, (b) is the expanded sectional view. In FIG. 2, the first motor 21 is fixed near the tip of the casing of the upper arm 14. The upper arm 14 is formed in a cylindrical shape from the rear end portion supported by the lower arm 13, and the front end portion is formed so as to be separable like a flange 14a. The first motor 21 is fixed so as to be housed in the flange 14a. The rotation center of the output shaft of the first motor 21 is the same as the center axis of the cylinder of the upper arm 14. The first motor 21 is a rotary motor having a hollow hole 21a coaxial with the output shaft. The hollow hole 21 a passes through the first motor 21. A reduction shaft 22 is rotatably supported with respect to the casing of the upper arm 14 so as to be adjacent to the output shaft of the first motor 21. The reduction shaft 22 is shifted from the center axis of the cylinder of the upper arm 14. A gear is fixed to the output shaft of the first motor 21, and a gear that meshes with the gear of the output shaft of the first motor 21 is formed at one end of the reduction shaft 22. The other end of the speed reduction shaft 22 is input to the first speed reducer 23. The first speed reducer 23 is fixed to the tip of the casing of the upper arm 14. The first speed reducer 23 is also formed with a hollow hole 23a similar to the first motor 21. The output shaft of the first reduction gear 23 and the output shaft of the first motor 21 are configured to be coaxial.
The base end of the first movable part 24 is fixed to the output shaft of the first speed reducer 23. Therefore, when the output shaft of the first motor 21 rotates, the rotation is decelerated by the speed reduction shaft 22 and the first speed reducer 23, and the first movable portion 24 fixed to the output shaft of the first speed reducer 23 becomes the wrist turning axis R. Rotate at. A second motor 25 is fixed to the first movable part 24. The second motor 25 is also a rotary motor like the first motor 21, but is a motor that does not need to have the hollow hole 21 a unlike the first motor 21. The output shaft of the second motor 25 is arranged so as to be orthogonal to the wrist turning axis R on the same plane. A second speed reducer 26 is fixed to the first movable portion 24 so as to be coaxial with the output shaft of the second motor 25. The second reduction gear 26 is a reduction gear that does not need to have a hollow hole. The output shaft of the second motor 25 is input to the second speed reducer 26. A lid 24 a that is a part of the first movable portion 24 is formed so as to be removable, and the lid 24 a is disposed so as to face the opposite output shaft side of the second motor 25.
The base end of the second movable portion 27 is fixed to the output shaft of the second speed reducer 26. The second movable portion 27 is formed in an L shape, the end portion of the long side of the L shape is fixed to the output shaft of the second speed reducer 26, and the short side of the L shape is parallel to the wrist bending axis B. Is arranged to maintain. Accordingly, when the output shaft of the second motor 25 rotates, the rotation is decelerated by the second speed reducer 26, and the second movable part 27 fixed to the output shaft of the second speed reducer 26 outputs the output of the second speed reducer 26. It rotates on the wrist bending axis B which is an axis. On the other hand, the first movable portion 24 is formed with a cover 24b that covers the proximal end portion of the second movable portion 27 that is fixed to the output shaft of the second speed reducer 26. The cover 24b is formed with a passage 24c communicating from the base end side of the first movable portion 24. The base end side of the first movable portion 24 is formed in a cylindrical shape, and the center of the cylinder communicates with the hollow hole 23a and the hollow hole 21a. A passage 27a is also formed on the proximal end side of the second movable portion 27, and the passage 27a communicates with the hollow hole 23a, the hollow hole 21a, and the passage 24c. When viewed from the front end side of the wrist mechanism 15, that is, when viewed from the end effector side described later, the width L of the first movable portion 24 is formed so as to be substantially symmetric with respect to a plane including a wrist rotation axis T described later. Yes. A third motor 28 is fixed near the tip of the second movable portion 27. The third motor 28 is also a rotary type motor like the first motor 21, but is a motor that does not need to have the hollow hole 21 a unlike the first motor 21. A third speed reducer 29 is fixed to the second movable portion 27 on the tip side of the third motor 28 so as to be coaxial with the output shaft of the third motor 28. The third speed reducer 29 is a speed reducer that does not need to have a hollow hole. The wrist rotation axis T which is the output shaft of the third motor 28 and the third movable part 30 is arranged to be orthogonal to the wrist bending axis B, and the wrist rotates when the second movable part 27 is rotated by the wrist bending axis B. The surface formed by the axis T is arranged so as to include the wrist turning axis R. One end of the third movable portion 30 is fixed to the output shaft of the third speed reducer 29. Accordingly, the third movable portion 30 rotates on the wrist rotation axis T by the rotation operation of the third motor 28 and the third speed reducer 29. An end effector (not shown) is fixed to the other end of the third movable portion 30.
Each of the motors (the first motor 21, the second motor 25, and the third motor 28) is supplied with power by a cable indicated by a cable 31, or a necessary signal is exchanged. The cable 31 passes through the inside of the upper arm 14 from the proximal end side, and then a part of the cable 31 is connected to the first motor 21. The cable 31 passes through the hollow hole 21 a and the hollow hole 23 a, passes through the cylindrical portion on the proximal end side of the first movable portion 24, and a part thereof is connected to the second motor 25. The cable 31 passes through the passage 24c, passes through the passage 27a, and is finally connected to the third motor 28.

Since the wrist mechanism 15 according to the present embodiment is configured as described above, the following effects are obtained.
First, unlike the prior art, the rotational driving force of the rotary motor installed at the rear end of the upper arm 14 is not transmitted to the wrist mechanism 15 at the tip of the upper arm 14 by the three rotational driving shafts. This greatly reduces the number of parts and simplifies the wrist mechanism 15, thereby improving the reliability of the wrist mechanism 15.
Further, the operating range of the robot is determined by the arm length of the upper arm 14 and the like. In this embodiment, when changing the operating range, the cylindrical length other than the flange 14a of the upper arm 14 may be simply changed. It becomes only.
In addition, when the user uses a robot, the wrist mechanism 15 often collides with the workpiece, and this often causes the parts of the wrist mechanism 15 to be replaced. In this embodiment, The first motor 21 can be easily replaced by removing the flange 14a, and the first speed reducer 23 can be easily replaced by removing the first movable part 24. The speed reducer 26 can be easily replaced by removing the lid 24a, and the third motor 28 and the third speed reducer 29 can be easily replaced by removing the second movable portion 27.
In this embodiment, since the speed reduction shaft 22 is provided between the first motor 21 and the first speed reducer 23, the speed reduction ratio can be adjusted here. Thus, when the weight or moment of the end effector is changed, it is necessary to change the motor capacity of the first motor 21 that is most susceptible to the influence, but in this embodiment, the speed is reduced without changing the first motor 21. By changing the reduction ratio of the shaft 22, it is possible to easily cope with it.

FIG. 3 shows a wrist mechanism 15 according to the second embodiment. (A) is an external view, (b) is the expanded sectional view. In FIG. 3, the first motor 21 is fixed near the tip of the casing of the upper arm 14. The upper arm 14 is formed in a cylindrical shape from the rear end portion supported by the lower arm 13, and the first motor 21 is fixed to the side surface of the front end portion. The output shaft of the first motor 21 is fixed so as to be perpendicular to the extending direction of the upper arm 14, and the output shaft of the first motor 21 is positioned so as to protrude into the cylinder of the upper arm 14. The first motor 21 is a rotary motor that does not require a hollow hole. A small bevel gear 21b is fixed to the output shaft of the first motor 21, and the large bevel gear 23b is positioned so as to mesh with the small bevel gear 21b. The large bevel gear 23b rotates on an axis orthogonal to the rotation axis of the output shaft of the first motor 21, and is rotatably supported on the upper arm 14 so as to rotate on the same axis as the central axis of the cylinder of the upper arm 14. Yes. The large bevel gear 23b is formed in a cylindrical shape. One end of the large bevel gear 23 b is input to the first reduction gear 23. The output shaft of the first speed reducer 23 is the same as the cylindrical central axis of the upper arm 14 and the rotational axis of the large bevel gear 23 b, and is located at the forefront of the upper arm 14. The first speed reducer 23 is a speed reducer having a through hole such as a hollow hole 23a.
The base end of the first movable part 24 is fixed to the output shaft of the first speed reducer 23. Therefore, when the output shaft of the first motor 21 rotates, the rotation is decelerated by the small bevel gear 21b, the large bevel gear 23b, and the first reduction gear 23, and the first movable portion fixed to the output shaft of the first reduction gear 23. Reference numeral 24 denotes a wrist turning axis R that is an output shaft of the first reduction gear. The first movable portion 24 is formed in a substantially cylindrical shape, and the cylindrical portion on the proximal end side thereof is inserted into the hollow holes 23 a and 23 b, and the most proximal end portion is rotatably supported by the upper arm 14. On the other hand, the first movable portion 24 has a cylinder on the tip side that opens toward a third motor 28 described later like an opening 24d. A second motor 25 is fixed to the side surface of the first movable part 24. Similarly to the first motor 21, the second motor 25 is a rotary motor and does not need to have a hollow hole. The output shaft of the second motor 25 is arranged so as to be orthogonal to the wrist turning axis R on the same plane. The output shaft of the second motor 25 does not protrude into the cylinder of the first movable part 24 and rotates in a space provided on the side surface of the first movable part 24. A gear is fixed to the output shaft of the second motor 25, and a gear is provided so as to be able to rotate in the same space so as to mesh with the output shaft. Further, a gear 26 a provided so as to mesh with the gear is provided, and this rotation is input to the second reduction gear 26. The output shaft of the second speed reducer 26 is disposed at a position orthogonal to the wrist turning axis R on the same plane. The second motor 25 and the second reduction gear 26 are arranged side by side with respect to the extending direction of the first movable portion 24. The second reduction gear 26 is a reduction gear that does not need to have a hollow hole.
The base end of the second movable portion 27 is fixed to the output shaft of the second speed reducer 26. That is, the second movable portion 27 rotates on the wrist bending axis B that is the rotation axis of the output shaft of the second reduction gear 26. The second movable portion 27 is formed in an L shape, the end portion of the long side of the L shape is fixed to the output shaft of the second speed reducer 26, and the short side of the L shape is parallel to the wrist bending axis B. Is arranged to maintain. Therefore, when the output shaft of the second motor 25 rotates, the rotation is decelerated by the plurality of gears and the second speed reducer 26, and the second movable portion 27 fixed to the output shaft of the second speed reducer 26 becomes the wrist bending shaft. Rotate at B A third motor 28 is fixed to the end portion of the short side of the L shape of the second movable portion 27. The third motor 28 is also a rotary motor, similar to the first motor 21, but is a motor that does not need to have a hollow hole. The output shaft of the third motor 28 is arranged to be parallel to the wrist bending axis B. A bevel gear is fixed to the output shaft of the third motor 28, and a bevel gear 29a is provided so as to mesh perpendicularly thereto. The rotation of the bevel gear 29 a is input to the third reduction gear 29. The third speed reducer 29 is fixed to the second movable part 27. The third speed reducer 29 is a speed reducer that does not need to have a hollow hole. The wrist rotation axis T, which is the output shaft, is arranged so as to be orthogonal to the wrist bending axis B, and the surface formed by the wrist rotation axis T when the second movable portion 27 is rotated by the wrist bending axis B is the wrist turning axis. It arrange | positions so that R may be included. One end of the third movable portion 30 is fixed to the output shaft of the third speed reducer 29. Accordingly, the third movable portion 30 rotates on the wrist rotation axis T by the rotation operation of the third motor 28 and the third speed reducer 29. An end effector (not shown) is fixed to the other end of the third movable portion 30.
Each of the motors (the first motor 21, the second motor 25, and the third motor 28) is supplied with power by a cable indicated by a cable 31, or a necessary signal is exchanged. After the cable 31 has passed through the inside of the upper arm 14 from the proximal end side, a part of the cable 31 is led out to the outside of the side surface on the distal end side of the upper arm 14 and connected to the first motor 21. The cable 31 passes through the cylindrical portion on the proximal end side of the first movable portion 24 and is then pulled out to the outside by the opening 24 d on the distal end side of the first movable portion 24, and is connected to the second motor 25 and the third motor 28. Connected.

Since the wrist mechanism 15 according to the present embodiment is configured as described above, the following effects are obtained.
First, unlike the prior art, the rotational driving force of the rotary motor installed at the rear end of the upper arm 14 is not transmitted to the wrist mechanism 15 at the tip of the upper arm 14 by the three rotational driving shafts. This greatly reduces the number of parts and simplifies the wrist mechanism 15, thereby improving the reliability of the wrist mechanism 15.
In addition, although the operation range of the robot is determined by the arm length of the upper arm 14 or the like, in this embodiment, when changing the operation range, it is only necessary to simply change the cylindrical length of the upper arm 14.
In addition, when the user uses a robot, the wrist mechanism 15 often collides with the workpiece, and this often causes the parts of the wrist mechanism 15 to be replaced. In this embodiment, The first motor 21 can be easily replaced by removing it from the side surface of the upper arm 14, and the first speed reducer 23 can be easily replaced by removing it from the tip of the upper arm 14. The second speed reducer 26 can be easily replaced by removing it from the side of the first movable part 24, and the third motor 28 and the third speed reducer 29 can be easily replaced by removing from the second movable part 27. .
Further, in the present embodiment, since there is no need for a device having a hollow hole other than the first reduction gear 23, it is possible to use a small one for each of these motors and each reduction gear, and the wrist mechanism 15 can be reduced in size.

FIG. 4 is a view showing the wrist mechanism 15 according to the third embodiment. (A) is an external view, (b) is the expanded sectional view. In FIG. 4, the first motor 21 is fixed to the rear end of the casing of the upper arm 14. The upper arm 14 is formed in a cylindrical shape from the rear end portion supported by the lower arm 13, and the first motor 21 is disposed on a surface that closes the rear end of the cylinder. The output shaft of the first motor 21 is fixed so as to be parallel to the extending direction of the upper arm 14, but is arranged so that the output shaft of the first motor 21 is shifted from the central axis of the cylinder of the upper arm 14. Has been. The first motor 21 is a rotary motor that does not require a hollow hole. On the other hand, a drive shaft 32 is rotatably disposed inside the upper arm 14, and the base end of the drive shaft 32 is connected to the output shaft of the first motor 21. The drive shaft 32 is disposed at a position shifted from the central axis of the cylinder of the upper arm 14. The front end side of the drive shaft 32 is input to the first speed reducer 23. The output shaft of the first speed reducer 23 is the same as the center axis of the cylinder of the upper arm 14 and is located at the forefront of the upper arm 14. The first speed reducer 23 is a speed reducer having a through hole such as a hollow hole 23a.
The base end of the first movable part 24 is fixed to the output shaft of the first speed reducer 23. Accordingly, when the output shaft of the first motor 21 rotates, the rotation is decelerated by the first speed reducer 23, and the first movable portion 24 fixed to the output shaft of the first speed reducer 23 becomes the output shaft of the first speed reducer 23. Rotate around the wrist turning axis R. The first movable portion 24 is formed in a substantially cylindrical shape, and the cylindrical portion on the proximal end side thereof is inserted into the hollow hole 23a, and the most proximal end portion is supported rotatably with respect to the upper arm 14. On the other hand, the first movable portion 24 has a cylinder on the tip side that opens toward a third motor 28 described later like an opening 24d. A second motor 25 is fixed to the side surface of the first movable part 24. Similarly to the first motor 21, the second motor 25 is a rotary motor and does not need to have a hollow hole. The output shaft of the second motor 25 is arranged so as to be orthogonal to the wrist turning axis R on the same plane. The output shaft of the second motor 25 does not protrude into the cylinder of the first movable part 24 and rotates in a space provided on the side surface of the first movable part 24. A gear is fixed to the output shaft of the second motor 25, and a gear is provided so as to be able to rotate in the same space so as to mesh with the output shaft. Further, a gear 26 a provided so as to mesh with the gear is provided, and this rotation is input to the second reduction gear 26. The output shaft of the second speed reducer 26 is disposed at a position orthogonal to the wrist turning axis R on the same plane. The second motor 25 and the second reduction gear 26 are arranged side by side with respect to the extending direction of the first movable portion 24. The second reduction gear 26 is a reduction gear that does not need to have a hollow hole.
The base end of the second movable portion 27 is fixed to the output shaft of the second speed reducer 26. The second movable portion 27 is formed in an L shape, the end portion of the long side of the L shape is fixed to the output shaft of the second speed reducer 26, and the short side of the L shape is parallel to the wrist bending axis B. Is arranged to maintain. Accordingly, when the output shaft of the second motor 25 rotates, the rotation is decelerated by the plurality of gears and the second speed reducer 26, and the second movable portion 27 fixed to the output shaft of the second speed reducer 26 performs the second speed reduction. It rotates on the wrist bending axis B which is the output shaft of the machine 26. A third motor 28 is fixed to the end portion of the short side of the L shape of the second movable portion 27. The third motor 28 is also a rotary motor, similar to the first motor 21, but is a motor that does not need to have a hollow hole. The output shaft of the third motor 28 is arranged to be parallel to the wrist bending axis B. A bevel gear is fixed to the output shaft of the third motor 28, and a bevel gear 29a is provided so as to mesh perpendicularly thereto. The rotation of the bevel gear 29 a is input to the third reduction gear 29. The third speed reducer 29 is fixed to the second movable part 27. The third speed reducer 29 is a speed reducer that does not need to have a hollow hole. The wrist rotation axis T, which is the output shaft, is arranged so as to be orthogonal to the wrist bending axis B, and the surface formed by the wrist rotation axis T when the second movable portion 27 is rotated by the wrist bending axis B is the wrist turning axis. It arrange | positions so that R may be included. One end of the third movable portion 30 is fixed to the output shaft of the third speed reducer 29. Accordingly, the third movable portion 30 rotates on the wrist rotation axis T by the rotation operation of the third motor 28 and the third speed reducer 29. An end effector (not shown) is fixed to the other end of the third movable portion 30.
Among the motors, the second motor 25 and the third motor 28 are supplied with power by a cable indicated by a cable 31 or a necessary signal is exchanged. The cable 31 passes through the inside of the upper arm 14 from the proximal end side, then passes through the cylindrical portion on the proximal end side of the first movable portion 24, and is drawn to the outside by the opening 24 d on the distal end side of the first movable portion 24. Thus, the second motor 25 and the third motor 28 are connected.

Since the wrist mechanism 15 according to the present embodiment is configured as described above, the following effects are obtained.
First, as in the prior art, the rotational driving force of the rotary motor installed at the rear end of the upper arm 14 is not transmitted to the wrist mechanism 15 at the tip of the upper arm 14 by the three rotational driving shafts. Since only one first motor 21 for driving the wrist turning axis R is disposed at the end and this rotational driving force is transmitted only by one drive shaft 32, the number of parts of the wrist mechanism 15 is greatly reduced. The wrist mechanism 15 is simplified, and the reliability of the wrist mechanism 15 can be improved.
In addition, when the user uses a robot, the wrist mechanism 15 often collides with the workpiece, and this often causes the parts of the wrist mechanism 15 to be replaced. In this embodiment, The first motor 21 can be easily replaced by removing it from the rear end of the upper arm 14, and the first speed reducer 23 can be easily replaced by removing it from the front end of the upper arm 14. The second speed reducer 26 can be easily replaced by removing it from the side of the first movable part 24, and the third motor 28 and the third speed reducer 29 can be easily replaced by removing from the second movable part 27. is there.
Further, in the present embodiment, since there is no need for a device having a hollow hole other than the first reduction gear 23, it is possible to use a small one for each of these motors and each reduction gear, and the wrist mechanism 15 can be reduced in size.

FIG. 5 shows a wrist mechanism 15 according to the fourth embodiment. (A) is an external view, (b) is the expanded sectional view. In FIG. 5, the first speed reducer 23 is fixed to the tip of the casing of the upper arm 14. The upper arm 14 is formed in a cylindrical shape from the rear end portion supported by the lower arm 13, and the front end portion is connected to the output shaft of the first speed reducer 23. The output shaft of the first speed reducer 23 is on the same axis as the central axis of the cylinder of the upper arm 14. The first speed reducer 23 is a speed reducer having a hollow hole 23a coaxial with the output shaft. The hollow hole 23 a passes through the first reduction gear 23. A first movable part 24 is provided so as to support the casing on the tip side of the first reduction gear 23. The first movable part 24 is formed in a substantially cylindrical shape, and the base end side of the first movable part 24 supports the casing of the first reduction gear 23 and includes the input shaft of the first reduction gear 23. Yes. The first motor 21 is fixed to the side surface of the first movable part 24. The first motor 21 is a rotary motor that does not require a hollow hole. The output shaft of the first motor 21 is disposed so as to protrude into the first movable portion 24. A small bevel gear 21b is fixed to the output shaft of the first motor 21, and a large bevel gear 23b is disposed on the first movable portion 24 so as to mesh with the small bevel gear 21b. The large bevel gear 23 b is disposed so as to be coaxial with the hollow hole 23 a and is supported rotatably with respect to the first movable portion 24. The large bevel gear 23b is a bevel gear formed in a cylindrical shape. The base end side of the large bevel gear 23 b is input to the first speed reducer 23. On the other hand, the cylindrical portion on the distal end side of the upper arm 14 is inserted into the hollow hole 23 a and the large bevel gear 23 b, and the distal end side thereof is rotatably supported by the first movable portion 24. Further, a cover 24b is detachably provided on the side surface of the first movable portion 24 so as to cover the second motor 25 provided in parallel with the first motor 21. As described above, when the output shaft of the first motor 21 rotates, the rotation is decelerated by the first reducer 23, and the first reducer 23 is moved against the upper arm 14 connected to the output shaft of the first reducer 23. All the tip side including it rotates on the wrist turning axis R. A second motor 25 is fixed to the side surface of the first movable part 24. The second motor 25 is also a rotary motor, like the first motor 21, but is a motor that does not need to have a hollow hole. The second motor 25 is fixed side by side with the first motor 21 in the extending direction of the first movable portion 24. The output shaft of the second motor 25 is arranged so as to be orthogonal to the wrist turning axis R on the same plane. A second speed reducer 26 is fixed to the first movable part 24. The second reduction gear 26 is a reduction gear that does not need to have a hollow hole. The output shaft of the second motor 25 is input to the second speed reducer 26. The output shaft of the second motor 25 and the output shaft of the second reduction gear 26 are disposed on the same axis. The wrist bending axis B, which is the output shaft of the second reduction gear 26, is disposed at a position orthogonal to the wrist turning axis R on the same plane.
The base end of the second movable portion 27 is fixed to the output shaft of the second speed reducer 26. The second movable portion 27 is formed in an L shape, the end portion of the long side of the L shape is fixed to the output shaft of the second speed reducer 26, and the short side of the L shape is parallel to the wrist bending axis B. Is arranged to maintain. Therefore, when the output shaft of the second motor 25 rotates, the rotation is decelerated by the second speed reducer 26, and the second movable portion 27 fixed to the output shaft of the second speed reducer 26 rotates on the wrist bending axis B. . On the other hand, the first movable portion 24 is formed with a cover 24 b that covers the proximal end portion of the second movable portion 27 that is fixed to the output shaft of the second reduction gear 26. The cover 24b is formed with a passage 24c communicating from the base end side of the first movable portion 24. A passage 27a is also formed on the proximal end side of the second movable portion 27, and the passage 27a communicates with the hollow hole 23a, the hollow hole 21a, and the passage 24c. A third motor 28 is fixed to the L-shaped short side of the second movable portion 27. The third motor 28 is also a rotary motor, similar to the first motor 21, but is a motor that does not need to have a hollow hole. A third speed reducer 29 is fixed to the second movable portion 27 on the tip side of the third motor 28 so as to be coaxial with the output shaft of the third motor 28. The output of the third motor 28 is input to the third speed reducer 29. The third speed reducer 29 is a speed reducer that does not need to have a hollow hole. The wrist rotation axis T that is the output shaft of the third speed reducer 29 is arranged so as to be orthogonal to the wrist bending axis B, and the wrist rotation axis T is formed when the second movable portion 27 is rotated by the wrist bending axis B. The surface is arranged so as to include the wrist pivot axis R. One end of the third movable portion 30 is fixed to the output shaft of the third speed reducer 29. Accordingly, the third movable portion 30 rotates on the wrist rotation axis T by the rotation operation of the third motor 28 and the third speed reducer 29. An end effector (not shown) is fixed to the other end of the third movable portion 30.

Each of the motors (the first motor 21, the second motor 25, and the third motor 28) is supplied with power by a cable indicated by a cable 31, or a necessary signal is exchanged. After the cable 31 has passed through the inside of the upper arm 14 from the base end side, the cable 31 is inserted into the cylinder at the distal end of the upper arm 14, and then a part of the cable 31 passes through a hole provided in the side surface of the upper arm 14. The first motor 21 and the second motor 25 are connected. The other part of the cable 31 passes through the passage 24c, passes through the passage 27a, and is finally connected to the third motor 28.

Since the wrist mechanism 15 according to the present embodiment is configured as described above, the following effects are obtained.
First, unlike the prior art, the rotational driving force of the rotary motor installed at the rear end of the upper arm 14 is not transmitted to the wrist mechanism 15 at the tip of the upper arm 14 by the three rotational driving shafts. This greatly reduces the number of parts and simplifies the wrist mechanism 15, thereby improving the reliability of the wrist mechanism 15.
In addition, although the operation range of the robot is determined by the arm length of the upper arm 14 or the like, in this embodiment, when changing the operation range, it is only necessary to simply change the cylindrical length of the upper arm 14.
In addition, when the user uses a robot, the wrist mechanism 15 often collides with the workpiece, and this often causes the parts of the wrist mechanism 15 to be replaced. In this embodiment, The first motor 21 and the second motor 25 can be easily replaced by removing the cover 24b, and the first speed reducer 23 can be easily replaced by removing from the upper arm 14, and the second speed reducer 26 can be easily replaced by removing the second motor 25, and the third motor 28 and the third speed reducer 29 can be easily replaced by removing the second movable part 27.
In the present embodiment, the first motor 21 and the second motor 25 are arranged side by side in the cover 24b, so that the maintenance and replacement thereof are easy to perform.

External side view of an industrial robot to which the present invention is applied The external view and expanded sectional view of the wrist part of Example 1 of this invention The external view and expanded sectional view of the wrist part of Example 2 of the present invention The external view and expanded sectional view of the wrist part of Example 3 of the present invention The external view and expanded sectional view of the wrist part of Example 4 of the present invention

11 Base 12 Turning head 13 Lower arm 14 Upper arm 14a Flange 15 Wrist mechanism

S Swivel axis L Front / rear axis U Oscillating axis R Wrist pivot axis B Wrist bending axis T Wrist rotation axis

21 first motor 21a hollow hole 21b small bevel gear 22 reduction shaft 23 first reduction gear 23a hollow hole 23b large bevel gear 24 first movable part 24a cover 24b cover 24d opening 24d second motor 26 second reduction gear 26a gear 27 second movable portion 27a passage 28 third motor 29 third reduction gear 29a bevel gear 30 third movable portion 31 cable 32 drive shaft

Claims (4)

In the wrist mechanism of an industrial robot provided at the tip of the upper arm and having a total of three axes of freedom,
The wrist mechanism is
A first motor and a first speed reducer that are fixed to the upper arm and rotate the first movable part on a wrist turning axis R along the upper arm;
A second motor fixed to the first movable part detachably from a side surface of the wrist mechanism and having an output shaft disposed so as to be orthogonal to the wrist turning axis R;
A second speed reducer arranged along the wrist turning axis R together with the second motor, fixed to the first movable part so as to be removable from a side surface of the wrist mechanism, and input of rotation of the output shaft of the second motor. When,
A second movable part that is fixed to the output shaft of the second speed reducer and rotates on a wrist bending axis B orthogonal to the wrist turning axis R;
A third motor and a third speed reducer that are fixed to the second movable part and rotate the third movable part on a wrist rotation axis T orthogonal to the wrist bending axis B;
An industrial robot wrist mechanism comprising: The first movable portion is formed in a cylindrical shape, and a tip end side of the cylinder opens toward the third motor;
The wrist mechanism for an industrial robot according to claim 1. The wrist mechanism according to claim 1, a lower arm that supports the upper arm so as to be swingable up and down, a swivel head that supports the lower arm so as to be swingable back and forth, and the swivel head as a vertical axis A base that is pivotably supported around,
A 6-axis industrial robot characterized by comprising The wrist mechanism according to claim 1, an upper lower arm that supports the upper arm so as to swing up and down, a lower lower arm that rotatably supports the upper lower arm, and the lower lower arm A swivel head that supports the swivel head so that it can swing back and forth, and a base that supports the swivel head so as to swivel about a vertical axis,
A total of 7-axis industrial robots.

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