JPH048491A - Noninterfering biaxial articulation in wire driving arm - Google Patents

Abstract

PURPOSE:To eliminate any interference by installing a gear train, which transmits rotation of a turning pulley to a second link at a reduction gear ratio of 1/2 via an intermediate member, in space between the pulley and the link, and setting up a differential gear in mesh with two bevel gears, between these gears concentrically installed with the turning pulley and a rotating pulley. CONSTITUTION:When a second link L2 is performed with only rotational motion, a turning pulley 12 is rotated by a wire 11. Rotation of this pulley 12 is transmitted to the second link L2 via a gear train as well as via an intermediate member 40, thus rotational motion is given to the second link L2, but since a reduction gear ratio in the gear train is set to a range of 1/2, the turning angle is 1/2 of that in the pulley 12. In this case, if a rotating pulley 22 is fixed, a bevel gear 24 for turning shaft drive use rotates as far as 1/2 of a turning angle of the pulley 12 is consequence. Consequently, rotational motion of the second link L2 is no longer produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a non-interference biaxial joint in a wire-driven arm used as an elbow joint of a robot arm.

[Prior Art] Conventionally, a wire-driven arm joint used as an elbow joint of a robot arm, etc. is required to be able to realize two degrees of freedom of rotational motion and rotational motion. The above-mentioned "rotational movement" is a bending and stretching movement of the second link that occurs around the rotational axis in a direction substantially orthogonal to the axis of the first link on the proximal end of the arm, and the above-mentioned "rotational movement" is ,
The torsional movement of the second link relative to the first link.

In order to achieve such two-degree-of-freedom motion of rotation and rotation at the joint, a conventional wire-driven arm is used.

[Problems to be Solved by the Invention] The technical problem of the present invention is to prevent interference between the mechanisms for rotation and rotation in the biaxial joint of the wire drive arm using the above-mentioned differential gear mechanism. , respectively (see, for example, Japanese Patent Publication No. 61-53199).

However, the former method requires two drive units, which inevitably complicates the mechanism, and furthermore poses a problem in wire arrangement. On the other hand, in the latter method, rotation and rotation are controlled by driving the two wires in the same direction or in relatively different directions, and therefore, the drive is controlled by taking into account the interference of the mechanisms for rotation and rotation. The differential gear type non-interfering two-axis joint of the present invention solves the above-mentioned problem in which each movement cannot be controlled by an independent wire drive. The second link is driven in the rotational direction and the rotational direction by rotating the rotational and rotational booms provided on the rotational axis of the second link on the distal end side of the link using a wire drive. In the joint, a gear train is provided between the rotating bobbin and the second link to transmit the rotation of the bobbin to the second link via an intermediate member at a reduction ratio of 1/2, between the boolean and the rotating boolean and the bevel gear installed on the same axis.
A differential gear meshing with both bevel gears is provided, and the shaft of the differential gear is rotatably supported by a bearing on a bevel gear for driving a rotary shaft, which is rotatably supported on the same axis as the bevel gear, and The bevel gear for shaft drive is
The liberga will rotate by 172 of the rotation angle of the boolean. Therefore, the bevel gear on the rotation shaft does not rotate with the rotation of the second link, and no rotational movement of the second link occurs.

[Function] When the second link is made to perform only rotational movement, the bevel gear on the rotation axis is meshed with the bevel gear. Rotate the pulley. The rotation of this boob is transmitted to the second link via the gear train and further via the intermediate member, giving rotational motion to the second link, but the reduction ratio in the gear train is set to 172. Therefore, the rotation angle is 172 times the rotation angle of the boob.

In this case, if the rotational boob is fixed, the rotational motion is transmitted by the differential gear to the bevel gear for driving the rotational shaft, and the rotational shaft gives rotational motion to the second link. In this case, if the rotating boot is fixed, the rotation of the intermediate member will be restricted, so the second
The links do not rotate.

Therefore, according to the non-interfering two-axis joint, interference between the mechanisms for rotation and rotation can be eliminated, and each can be driven and controlled using independent wires.

[Embodiment] FIG. 1 shows an embodiment of a non-interference two-axis joint according to the present invention, which can be effectively used as an elbow joint of a robot arm, etc.

This joint basically uses a differential gear mechanism and uses a wire inserted through a flexible tube to rotate a boob attached to the differential gear mechanism. A pulley 12 for rotation, a gear 13 and a bevel gear 14 integrated with the pulley 12 are attached, and a pulley 22 for rotation and a bevel gear 23 around which a wire 21 is wound are attached to the rotating shaft 20, and a The movement in the intervening direction between the two links L2 can be independently driven using different wires.

More specifically, as shown in FIG.
1 and the second link L2 on the distal end side.

At the tip of the first link L1, a rotating shaft 10, 20, 30 in a direction substantially orthogonal to the axis of the link L1 is rotatably attached on the same axis (hereinafter referred to as the rotating axis A). I support it. A gear 31 is attached to the rotating shaft 10. The axis of rotation A given by these axes of rotation 10, 20, 30 becomes the central axis of rotation around which the second link L2 rotates with respect to the first link L.

The wire 11 wound around the rotation pulley 12 consists of two wires wound around the pulley 12 in opposite directions, and each of these two wires has its tip attached to the pulley 12.
It is fixed on the surface of 2. Therefore, pulling one wire causes the pulley 12 to rotate in one direction, and pulling the other wire causes the pulley 12 to rotate in the opposite direction. The same applies to the wire 21 wound around the rotation pulley 22 on the rotating shaft 20. Each of the above wires 11.
21 passes through the first link L1 and is led out to the proximal end side of the link.

The bevel gear 23 attached to the common differential gear 51.
51 are engaged. These differential gears 51 and 51 have their shafts 52 and 52 rotatably supported by bearings 53 on a rotating shaft driving bevel gear 24 which is rotatably supported on the rotating shaft 20.

Helical gear 4 rotatably supported by link L+ of 1
3 is meshed with a helical gear 31 fixed on a rotating shaft 30. Since the gear 13 and the gear 42 have the same number of teeth, rotation at the same speed is transmitted from the rotary shaft 10 to the shaft 41, but the rotation from the helical gear 43 to the helical gear 31 is transmitted by reducing the reduction ratio by l/2. Therefore, when the rotating shaft 10 rotates N times, the rotating shaft 30 rotated through the gear train rotates N/2 times.

A bevel gear 55 is attached that meshes with the bevel gear 14 attached to the rotating shaft 10 and the bevel gear 24 which is rotatable by 2 degrees of the rotating shaft. The axis of the rotation shaft 54 (hereinafter referred to as rotation axis B) provides a central axis along which the second link L2 rotates (twists) relative to the first link L+.

Next, the operation of the non-interference two-axis joint having the above configuration, that is, the operation when the second link 2 is rotated and rotated will be explained.

Rotational Movement: When the second link L2 is to perform only a rotational movement around the rotational axis A without rotational movement, the rotational pulley 12 is rotated by the wire 11. In this case, the rotation pulley 22 is fixed by a wire 21. The pulley 12 rotates through a gear train, that is, N rotations from the pulley 12 to the gear 13-, but since the bevel gear 23 is fixed, the bevel gear 24 is rotated by the differential gears 51 and 51 to the rotating shaft 20. It will rotate around N/2. on the other hand.

The intermediate member 40 supporting the bevel gear 55 also rotates N/2 around the rotation axis A as described above. A rotational motion is given.

As described above, since the pulley 22 for rotational movement is fixed by the wire 21, the bevel gear 23 does not rotate during the rotational movement. On the other hand, when the rotary motion pulley 12 is rotated N, the driving force is transmitted from the gear 13 to the intermediate member 40 as described above, but the reduction ratio between the helical gear 43 and the helical gear 31 is reduced to 172 , the intermediate member 40 and the second link L2
rotates N/2 around the axis of rotation A. At this time,
At the same time, the bevel gear 14 can only provide rotational movement around the rotational axis A.

Rotation Movement: When the second link L2 is to perform only one rotation movement without causing any rotation movement, the rotation pulley 22 is rotated by the wire 21. In this case, the rotating pulley 12 is fixed by the wire 11. The rotation of the pulley 22 is transmitted in the order of pulley 22 → bevel gear 23 → differential gear 51.51 - bevel gear 24 → bevel gear 55 → rotation shaft 54 → second link L2, thereby causing rotational movement to second link L2. is given.

As mentioned above, since the rotating pulley 12 is fixed by the wire 11, the bevel gear 14, the gear 13, the gear 42. Even though the helical gear and the rotary bobbin shaft are arranged on the same rotational axis A, by mechanically compensating for their rotational interference, the motion in the rotational direction and the rotational direction can be separated from each other. Can be driven independently by wire.

It is transmitted from the gear 23 to the rotation shaft 54, but the bevel gear 1
4 does not rotate, the bevel gear 24 rotates N72 around the rotating shaft 20. At this time, the intermediate member 40 has a rotation axis of 1 m.
Since the bevel gear 55 does not rotate around the rotational axis A, the rotational movement of the bevel gear 55 around the rotational axis six times is restricted, and eventually the movement of the bevel gear 24 around the rotational axis six times is converted into the movement of the bevel gear 55 around the rotational axis eight, and the bevel gear 55 rotates around the rotational axis 8. The link 2 does not rotate around six rotational axes, but rotates only N/2 rotations.

In this way, according to the above-mentioned non-interference two-axis joint, interference between the mechanisms for rotation and rotation is eliminated, and the rotation and rotation of the second link are driven by independent wires. can be controlled with.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a non-interference biaxial joint according to the present invention. Ll...first link, L2...second link, 10,
20.30...Rotation axis, 11.21...Wire, 1
2... Rotating pulley, 14.23.55... Bevel gear, 22... Rotating pulley, 24... Bevel gear for rotating shaft drive. 40...Intermediate member, 51...Differential gear, 52...
Shaft, 53.-Bearing portion, 54.. Rotation axis. No.

Claims (1)

[Scope of Claims] 1. A rotation link provided between a first link on the proximal end side and a second link on the distal end side, and provided on the rotational axis of the second link with respect to the first link. A joint in which a second link is driven in a rotational direction and a rotational direction by rotating each rotational pulley by a wire drive, and a joint is provided between the rotational pulley and the second link. A gear train is provided that transmits the rotation of the pulley to the second link via an intermediate member at a reduction ratio of 1/2, and a bevel gear is provided coaxially with the rotation pulley and the rotation pulley. A differential gear that meshes with the bevel gear is provided, and the shaft of the differential gear is rotatably supported by a bearing on a bevel gear for driving a rotary shaft that is rotatably supported coaxially with the bevel gear, and A non-interference two-axis joint in a wire-driven arm, characterized in that a bevel gear for driving is meshed with a bevel gear on a rotation axis that is attached to a second link and rotatably supported by the intermediate member.