JP2021000676A - Rotary device - Google Patents

Abstract

To enable a load, which is imposed on wiring, to be reduced with respect to a conventional constitution.SOLUTION: A rotary device comprises: an arm 1; an arm 2 that has a hollow joint part 21 rotatably connected to the arm 1; a torque sensor 3 that is attached to the joint part 21; wiring 4, one end of which is positioned within the arm 1 via the inside of the joint part 21, the other end of which is positioned within the arm 2, and which can be rotated around a shaft center; and wiring 5 that is inserted into the arm 2 from within the arm 1 via the inside of the wiring 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotating device having a torque sensor.

Conventionally, there has been known a robot arm in which a torque sensor is attached to each joint and force control is performed based on the torque detected by the torque sensor (see, for example, Patent Document 1). In this robot arm, wiring is passed between the arms via the inside of the joint portion. On the other hand, when the joint portion is thin and there are a plurality of wires, the rotation of the arm may cause the wires to be entangled and twisted, and the twisting torque may be applied as a load on the wires. Then, this load becomes a load at the joint portion and becomes a measurement disturbance to the torque sensor.

On the other hand, a ceiling-mounted robot that can reduce the load due to wiring entanglement is known (see, for example, Patent Document 2). In this ceiling-mounted robot, a pipe is provided in which one end is fixed inside the first arm and the other end is located inside the second arm via the inside of the joint portion connecting the first arm and the second arm. , The wiring is passed through the inside of the pipe. Further, in the wiring, the other end side of the pipe and the second arm side are fixed.
By applying this configuration to a robot arm having a torque sensor as described above, it is possible to reduce the load due to the entanglement of wiring.

However, in the configuration disclosed in Patent Document 2, one end of the pipe is fixed inside the first arm, and the other end side of the pipe and the second arm side of the wiring are fixed. Therefore, when the second arm rotates, the wiring itself is twisted inside the second arm, and a load is generated on the wiring. Then, this load becomes a load at the joint portion and becomes a measurement disturbance to the torque sensor.

International Publication No. 2009/083111 Japanese Unexamined Patent Publication No. 2015-211999

As described above, in the robot arm having the torque sensor, the load due to the kinking generated in the wiring causes a measurement disturbance to the torque sensor, and therefore improvement is required. This problem is not limited to the robot arm, but the same applies to other rotating devices having a torque sensor.

The present invention has been made to solve the above-mentioned problems, and to provide a rotating device having a torque sensor, which can reduce the load applied to wiring with respect to the conventional configuration. I am aiming.

The robot arm according to the present invention includes a first housing, a second housing having a hollow joint portion rotatably connected to the first housing, and a torque sensor attached to the joint portion. One end is located inside the first housing and the other end is located inside the second housing via the inside of the joint portion, via a pipe that can rotate around the axis and inside the pipe. It is characterized by having a wiring passed from the inside of the first housing to the inside of the second housing.

According to the present invention, since the configuration is as described above, it is possible to reduce the load on the wiring in the rotating device having the torque sensor as compared with the conventional configuration.

It is a schematic cross-sectional view which shows the structural example of the robot arm which concerns on Embodiment 1. FIG. It is a schematic cross-sectional view which shows the structural example of the robot arm which concerns on Embodiment 1. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a robot arm (rotating device) according to the first embodiment.
As shown in FIG. 1, the robot arm includes an arm (first housing) 1, an arm (second housing) 2, a torque sensor 3, a pipe 4, and a wiring 5.

The arm 1 is a housing having a cavity inside. A driving motor 6 is provided inside the arm 1. The driving motor 6 rotates the joint portion 21, which will be described later.

The arm 2 is a housing having a cavity inside. The arm 2 has a joint portion 21. The joint portion 21 is a portion rotatably connected to the arm 1 and has a speed reducer. The speed reducer reduces the rotational speed of the power applied by the prime mover motor 6 and outputs it. The joint portion 21 is formed in a hollow shape. The hollow joint portion 21 communicates the inside of the arm 2 with the inside of the arm 1.

The torque sensor 3 is attached to the joint portion 21 of the arm 2 and detects the torque applied to the joint portion 21. In FIG. 1, a disk-shaped torque sensor 3 having a hole in the axial center is used, and the torque sensor 3 is the same (including substantially the same meaning) on the arm 2 side (output side of the reducer) of the joint portion 21. It is mounted on the axis.

The pipe 4 is a member that is rotatable around the axis, with one end located inside the arm 1 and the other end located inside the arm 2 via the inside of the joint portion 21. That is, the pipe 4 has a small outer diameter with respect to the inner diameter of the joint portion 21, and is configured to have a length that can be arranged from the inside of the arm 1 to the inside of the arm 2 via the inside of the joint portion 21. There is. The pipe 4 may be made of any member, but when the joint portion 21 is thin, it is made of a member (for example, stainless steel) that can secure strength even if it is thin. Further, the pipe 4 may have a diameter that causes friction with the wiring 5 due to the rotation of the joint portion 21 so that the pipe 4 can be easily rotated in response to the twist of the wiring 5 passed through the inside.

In FIG. 1, the pipe 4 is rotatably supported by a bearing portion (first bearing portion) 7 and a bearing portion (second bearing portion) 8. The bearing portion 7 is provided inside the arm 1 and rotatably supports one end side of the pipe 4. That is, in the bearing portion 7, the outer ring is fixed inside the arm 1, and one end side of the pipe 4 is fixed to the inner ring. The bearing portion 8 is provided inside the arm 2 and rotatably supports the other end side of the pipe 4. That is, in the bearing portion 8, the outer ring is fixed inside the arm 2, and the other end side of the pipe 4 is fixed to the inner ring.

The wiring 5 is passed from the inside of the arm 1 to the inside of the arm 2 via the inside of the pipe 4. The wiring 5 is, for example, a power cable or a communication cable. One end of the wiring 5 shown in FIG. 1 is connected to a substrate (not shown) of the arm 1, and the other end is connected to a substrate (not shown) of the arm 2. Although FIG. 1 shows a case where the number of wires 5 is one, usually, a plurality of wires 5 are bundled together.

Next, the effect of the robot arm according to the first embodiment shown in FIG. 1 will be described.
It is assumed that the pipe 4 is not rotatable (fixed) in the robot arm according to the first embodiment shown in FIG. In this case, when the arm 2 rotates, the wiring 5 rubs against the pipe 4, and kinks occur on the arm 1 side or the arm 2 side of the wiring 5 with the rubbed portion as a fixed end, and the torsion torque thereof with respect to the wiring 5 It becomes a load. Then, this load becomes a load at the joint portion 21, and becomes a measurement disturbance to the torque sensor 3. Further, in this case, there are individual differences in the twisting method of the wiring 5, and the measurement accuracy of the torque sensor 3 varies.

On the other hand, in the robot arm according to the first embodiment shown in FIG. 1, a rotatable pipe 4 is provided in which one end is located inside the arm 1 and the other end is located inside the arm 2. Wiring 5 is passed through the inside of the pipe 4. As a result, in this robot arm, even if the arm 2 rotates and twists occur on the arm 1 side of the wiring 5, for example, the pipe 4 rotates in the twisting direction, so that the wiring 5 also twists on the arm 2 side. Is transmitted (see reference numeral 101). As a result, in this robot arm, the wiring 5 is twisted in a wide range extending from the arm 1 side to the arm 2 side, so that the load applied to the wiring 5 is reduced in proportion to the range. Therefore, in this robot arm, the influence (measurement disturbance) of the load of the wiring 5 on the measured value of the torque sensor 3 can be reduced. The same applies to the case where the arm 2 rotates and the wiring 5 is twisted on the arm 2 side. In the wiring 5 shown in FIG. 1, one end is connected to the substrate of the arm 1 and the other end is connected to the substrate of the arm 2. Therefore, when the arm 2 rotates, these fixed ends (reference numerals 102, 103) are connected. The end portion shown in (1) serves as a rotation fulcrum, causing kinking.

In the above description, the case where the robot arm is a biaxial robot arm including two arms (arm 1 and arm 2) is shown. However, the robot arm is not limited to this, and the robot arm may be a multi-axis robot arm having three or more axes. In this case, one of the two adjacent arms corresponds to the arm 1, and the other corresponds to the arm 2.

Further, in the above, the wiring 5 shows a case where one end is connected to the substrate of the arm 1 and the other end is connected to the substrate of the arm 2. However, the present invention is not limited to this, and the wiring 5 may be configured to be connected to another configuration via an arm (arm 1 or arm 2).

As described above, according to the first embodiment, the robot arm is attached to the arm 1, the arm 2 having the hollow joint portion 21 rotatably connected to the arm 1, and the joint portion 21. An attached torque sensor 3, a pipe 4 having one end located inside the arm 1 and the other end located inside the arm 2 via the inside of the joint portion 21, and a pipe 4 that can rotate around the axis, and a pipe. The wiring 5 passed from the inside of the arm 1 to the inside of the arm 2 via the inside of the arm 4 is provided. As a result, the rotating device according to the first embodiment can reduce the load applied to the wiring 5 as compared with the conventional configuration.

Embodiment 2.
In the robot arm according to the first embodiment, the case where the pipe 4 is rotatably supported by the bearing portion 7 provided inside the arm 1 and the bearing portion 8 provided inside the arm 2 is shown.
On the other hand, as shown in FIG. 2, the pipe 4 may be rotatably supported by the bearing portion 9 provided inside the joint portion 21. That is, in the bearing portion 9, the outer ring is fixed inside the joint portion 21, and the central portion of the pipe 4 is fixed to the inner ring. The same effect as that of the robot arm according to the first embodiment shown in FIG. 1 can be obtained with respect to the robot arm according to the second embodiment shown in FIG.

That is, in the robot arm according to the second embodiment shown in FIG. 2, a rotatable pipe 4 is provided in which one end is located inside the arm 1 and the other end is located inside the arm 2, and the pipe 4 is provided. Wiring 5 is passed through the inside of. As a result, in this robot arm, even if the arm 2 rotates and twists occur on the arm 1 side of the wiring 5, for example, the pipe 4 rotates in the twisting direction, so that the wiring 5 also twists on the arm 2 side. Is transmitted (see reference numeral 201). As a result, in this robot arm, the wiring 5 is twisted in a wide range extending from the arm 1 side to the arm 2 side, so that the load applied to the wiring 5 is reduced in proportion to the range. Therefore, in this robot arm, the influence (measurement disturbance) of the load of the wiring 5 on the measured value of the torque sensor 3 can be reduced. The same applies to the case where the arm 2 rotates and the wiring 5 is twisted on the arm 2 side. In the wiring 5 shown in FIG. 2, one end is connected to the substrate of the arm 1 and the other end is connected to the substrate of the arm 2. Therefore, when the arm 2 rotates, these fixed ends (reference numerals 202, 203) are connected. The end portion shown in (1) serves as a rotation fulcrum, causing kinking.

Further, FIG. 2 shows a case where the bearing portion 9 is provided inside the joint portion 21. However, the present invention is not limited to this, and the bearing portion 9 may be provided inside the disk-shaped torque sensor 3 having a hole in the axial center.

In the first and second embodiments, the case where the rotating device is a robot arm is shown. However, the rotating device is not limited to this, and the rotating device includes a first housing, a second housing having a joint portion rotatably connected to the first housing, and a torque sensor attached to the joint portion. Any rotating device provided with and may be used.

Further, within the scope of the invention, the present invention can be freely combined with each embodiment, modified any component of each embodiment, or can omit any component in each embodiment. is there.

1 arm (1st housing)
2 arm (second housing)
3 Torque sensor 4 Piping 5 Wiring 6 Motor motor 7 Bearing 8 Bearing 9 Bearing 21 Joint

Claims (5)

With the first housing
A second housing having a hollow joint portion rotatably connected to the first housing, and a second housing.
The torque sensor attached to the joint and
A pipe that is rotatable around the axis and one end is located inside the first housing and the other end is located inside the second housing via the inside of the joint portion.
A rotating device including wiring that is passed from the inside of the first housing to the inside of the second housing via the inside of the piping. A first bearing portion provided inside the first housing and rotatably supporting one end side of the pipe.
The rotating device according to claim 1, further comprising a second bearing portion provided inside the second housing and rotatably supporting the other end side of the pipe. The rotating device according to claim 1, further comprising a bearing portion provided inside the joint portion and rotatably supporting the pipe. The torque sensor is configured in a disk shape having a hole in the axis.
The rotating device according to claim 1, further comprising a bearing portion provided inside the torque sensor and rotatably supporting the pipe. The rotating device according to any one of claims 1 to 4, wherein the pipe has a diameter that causes friction with the wiring due to the rotation of the joint portion.

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