JPH064230B2 - Non-interfering biaxial joint in wire drive arm - Google Patents

Description

TECHNICAL FIELD The present invention relates to a non-interfering biaxial joint in a wire driving arm suitable for use as an elbow joint of a robot arm or the like.

[Prior Art] Conventionally, in a wire-driven arm joint used as an elbow joint or the like of a robot arm, it is required to realize a two-degree-of-freedom motion of a rotary motion and a rotational motion. The "rotational movement" is a bending and stretching movement of the second link that occurs around the rotation axis in a direction substantially orthogonal to the axis of the first link on the proximal end side of the arm, and the "rotational movement" is ,
The twisting movement of the second link relative to the first link.

In order to realize such a two-degree-of-freedom motion of rotation and rotation in a joint, in a conventional wire drive arm, usually, rotation and rotation drive units are arranged separately or a differential gear mechanism is provided. A method of controlling rotation and rotation while considering interference of the mechanism is used (for example, see Japanese Patent Publication No. 61-53199).

However, in the former method, two driving parts are required, which inevitably complicates the mechanism and causes 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 relatively different directions, and therefore drive is performed in consideration of interference of the mechanism for rotation and rotation. It must be controlled and each movement cannot be controlled by an independent wire drive.

[Problems to be Solved by the Invention] A technical problem to be solved by the present invention is to eliminate interference of mechanisms for rotation and rotation in a biaxial joint of a wire drive arm using the above-mentioned differential gear mechanism, The purpose is to obtain a non-interfering biaxial joint that can be driven and controlled by independent wires.

[Means for Solving the Problems] The differential gear type non-interference 2 of the present invention for solving the above problems.
The shaft joint includes a second link on the distal end side with respect to a first link on the proximal end side.
In the joint configured to drive the second link in the rotational direction and the rotational direction by rotating each of the rotational and rotational pulleys provided on the rotational axis of the second link by wire drive, the rotational pulley Between the second link and the second link through the intermediate member at a speed reduction ratio of 1/2
A gear train for transmitting to the link of, and a bevel gear provided coaxially with the rotating pulley and the rotating pulley is provided with a differential gear that meshes with both bevel gears. The bevel gear for driving the rotating shaft is rotatably supported by a bearing on the rotating shaft driving bevel gear that is rotatably supported coaxially with the bevel gear.
It is characterized in that it is meshed with a bevel gear on a rotary shaft which is attached to the second link and is rotatably supported by the intermediate member.

[Operation] When the second link is caused to rotate only, the rotating pulley is rotated by the wire. The rotation of this pulley is transmitted to the second link through the gear train and further through the intermediate member, and the rotary motion is given to the second link, but the reduction ratio in the gear train is set to 1/2. Therefore, the rotation angle is 1/2 of the rotation angle of the pulley. In this case, if the rotating pulley is fixed, the bevel gear for driving the rotating shaft is rotated by 1/2 of the rotation angle of the pulley due to the differential gear during the above rotational movement.
Therefore, the bevel gear on the rotating shaft does not rotate with the rotation of the second lik, and the rotating motion of the second link does not occur.

When the second link is caused to perform only the turning movement, the turning pulley is rotated by the wire. The rotation of the pulley is transmitted to the bevel gear on the rotating shaft via the differential gear and the bevel gear for driving the rotating shaft, and the rotating shaft imparts a rotating motion to the second link. In this case, if the rotating pulley is fixed, the rotation of the intermediate member is restricted, so that the second link does not rotate.

Therefore, according to the non-interfering biaxial joint, it is possible to eliminate the interference of the mechanism for the rotation and rotation motions, and to drive and control each of them by an independent wire.

[Embodiment] FIG. 1 shows an embodiment of a non-interfering biaxial joint according to the present invention, which can be effectively used as an elbow joint or the like of a robot arm.

This joint basically uses a differential gear mechanism and adopts a method in which a pulley attached to the differential gear mechanism is rotationally driven by a wire inserted in a flexible tube, and the above-described rotation direction (joint bending or stretching It enables movements in a rotating direction) and a rotating direction (twisting direction) without interference. Therefore,
The movement in the rotational direction and the movement in the rotational direction can be independently driven by separate wires.

More specifically, as shown in FIG. 1, this joint is the first link L ₁ on the proximal side of the wire drive arm.
And the second link L ₂ on the tip side.

At the tip of the first link L ₁ , the rotary shafts 10, 20, 30 in a direction substantially orthogonal to the axis of the link L ₁ rotate on the same axis (hereinafter referred to as the rotation axis A). It is supported freely. A rotating pulley 12 around which a wire 11 is wound, a gear 13 and a bevel gear 14 integrated with the pulley 12 are attached to the rotating shaft 10, and a rotating pulley 22 around which a wire 21 is wound and a rotating pulley 22 and a bevel gear 14 are attached to the rotating shaft 20. The bevel gear 23 is attached, and the intermediate member 40 and the bevel gear 24 for driving the rotating shaft, which are interposed between the first link L ₁ and the second link L ₂ , are rotatably supported. In addition, the rotary shaft 30 includes an intermediate member 40.
A helical gear 31 fixed integrally with is attached. The axis of rotation A given by these axes of rotation 10, 20, 30
Is the center axis of rotation about which the second link L ₂ rotates with respect to the _first link L ₁ .

The wire 11 wound around the rotating pulley 12 is
It consists of two wires wound in the opposite direction to 12,
The ends of these two wires are fixed to the surface of the pulley 12. 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 rotating pulley 22 on the rotary shaft 20. Each of the wires 11 and 21 is connected to the first link L ₁
It is led out to the base end side of the link through the inside.

Further, the gear 13 mounted on the rotary shaft 10 is meshed with the gear 42 on the shaft 41 rotatably supported by the first link L ₁ , and is fixed coaxially with the gear 42 to fix the first link. A helical gear 43 rotatably supported by L ₁ is meshed with a helical gear 31 fixed on a rotary shaft 30. Gear 13 and gear
Since the number of teeth of 42 is the same, rotation of the same speed is transmitted from the rotary shaft 10 to the shaft 41, but transmission of rotation from the helical gear 43 to the helical gear 31 is performed by setting the reduction ratio to 1/2. Therefore, when the rotating shaft 10 makes N rotations, the rotating shaft 30 which is rotationally driven through the gear train makes N / 2 rotations.

A common differential gear 51, 51 is meshed with the bevel gear 14 attached to the rotary shaft 10 and the bevel gear 23 attached to the rotary shaft 20. These differential gears 51, 51 are rotatably supported by bearings 53 on a rotating shaft driving bevel gear 24 that rotatably supports the shafts 52, 52 on the rotary shaft 20.

Further, the intermediate member 40 rotatably supports a rotary shaft 54 fixed to the base end of the second link L ₂ , and the rotary shaft 54
Further, a bevel gear 55 that meshes with a bevel gear 24 that is rotatable on the rotary shaft 20 is attached. The axis line of the rotation shaft 54 (hereinafter, referred to as the rotation axis line B) gives a central axis line around which the second link L ₂ rotates (twisting motion) with respect to the _first link L ₁ .

Next, the operation of the non-slightly biaxial joint having the above-described configuration, that is, the operation when the second link L ₂ is rotated and rotated will be described.

Rotational movement: If the second link L ₂ is not rotated, but only rotated about the rotation axis A, the wire 11
The pulley 12 for rotation is rotated by. In this case,
The rotating pulley 22 is fixed by the wire 21. The rotation of the pulley 12 is via the gear train, i.e., the pulley 12
→ Gear 13 → Gear 42 → Shaft 41 → Helical gear 43 → Helical gear 31 → Intermediate member 40 → Second link L ₂ are transmitted in this order, whereby the second link L ₂ is given a rotational motion about the rotation axis A. To be

As described above, since the pulley 22 for rotating motion is fixed by the wire 21, the bevel gear is used during the rotating motion.
23 does not rotate. On the other hand, when the pulley 12 for rotational movement is rotated N times, the driving force thereof is the gear 13 as described above.
Is transmitted to the intermediate member 40 from, but since the reduction ratio between the helical gear 43 and the helical gear 31 is set to 1/2,
The intermediate member 40 and the second link L ₂ rotate N / 2 around the rotation axis A. At this time, the bevel gear 14 also makes N rotations at the same time, but since it is fixed to the bevel gear 23, the bevel gear 24 rotates N / 2 around the rotation shaft 20 by the differential gears 51, 51. On the other hand, the intermediate member 40 that supports the bevel gear 55 also rotates N / 2 around the rotation axis A as described above. Therefore, the rotational movement of the bevel gear 55 around the rotation axis B does not occur.

That is, it is possible to give only the rotational movement about the rotation axis A without rotating the second link L ₂ .

Rotational movement: When the second link L ₂ is caused to perform only the rotational movement without causing the rotational movement, the wire 21 rotates the rotational pulley 22. In this case, the pulley for rotation
12 is fixed by wire 11. The rotation of the pulley 22 is transmitted in the order of the pulley 22 → bevel gear 23 → differential gears 51, 51 → bevel gear 24 → bevel gear 55 → rotating shaft 54 → second link L ₂ and thereby to the second link L ₂ . A rotational movement is given.

As described above, since the rotating pulley 12 is fixed by the wire 11, the bevel gear is used during the above-described turning motion.
14, gear 13, gear 42, helical gear 43, helical gear 3
1, the intermediate member 40 does not rotate. On the other hand, when the pulley 22 for rotating motion is rotated N times, the driving force is transmitted from the bevel gear 23 to the rotating shaft 54 as described above, but since the bevel gear 14 does not rotate, the bevel gear 24 causes the bevel gear 24 to rotate. Rotate N / 2 around. At this time, the intermediate member 40 has the rotation axis A
Since the bell gear 55 does not rotate about the rotation axis A, the rotation movement of the bell gear 55 about the rotation axis A is restricted, and the movement of the bevel gear 24 about the rotation axis A is converted into the movement of the bevel gear 55 about the rotation axis B. The link L ₂ of does not rotate about the rotation axis A, but only makes N / 2 rotations.

As described above, according to the non-interference biaxial joint, although the pulley shafts for rotation and rotation are arranged on the same rotation axis A, the interference of those rotations is mechanically compensated. Thus, the movement in the rotation direction and the movement in the rotation direction can be independently driven by separate wires.

[Effects of the Invention] As described in detail above, according to the present invention, in the biaxial joint of the wire drive arm using the differential gear mechanism, the interference of the mechanism for the rotation and the rotation motion is eliminated, and The drives for rotation and rotation of the two links can each be controlled by independent wires.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a non-interfering biaxial joint according to the present invention. L ₁ ... first link, L ₂ ... second link, 10,20,30 ... rotating shaft, 11,21 ... wire, 12 ... rotating pulley, 14,23,55 ... bevel gear , 22 ... ・ Pulley for turning, 24 ・ ・ Bevel gear for driving turning shaft, 40 ・ ・ Intermediate member, 51 ・ ・ Differential gear, 52 ・ ・ Shaft, 53 ・ ・ Bearing part, 54 ・ ・ Rotating shaft

Claims (1)

[Claims] 1. A rotating and rotating member provided between a first link on the proximal end side and a second link on the distal end side, and provided on the rotation axis of the second link with respect to the first link. A joint in which each pulley is driven by a wire to drive the second link in the rotation direction and the rotation direction, and the rotation of the pulley is between the rotation pulley and the second link. A gear train is provided to transmit to the second link through the intermediate member at a reduction ratio of 1/2, and meshes with both bevel gears between the rotating pulley and the bevel gear provided coaxially with the rotating pulley. A differential gear is provided, and the shaft of the differential gear is rotatably supported by a bearing portion on a bevel gear for driving a rotating shaft that is rotatably supported coaxially with the bevel gear. Attach the bevel gear to the second link. Te were meshed with the bevel gear on the rotation shaft which is rotatably supported to the intermediate member, the non-interfering biaxial joints in wire driving arm, characterized in that.