JPS6153199B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lightweight, highly rigid articulated arm.

Conventionally, various mechanisms have been adopted as joint drive mechanisms for multi-jointed arms in robots, etc.
As the weight of each joint increases, it becomes necessary to increase the strength of the arm itself accordingly, so it is required to reduce the weight of the joints and the like as much as possible.
Furthermore, in order to reduce the weight, it is necessary to provide the actuator for driving the joint as close to the base of the arm as possible.

On the other hand, although it has been known to use a differential gear mechanism for the joint drive mechanism of multi-jointed arms, it is difficult to incorporate it into articulated arms due to its lightweight and high rigidity structure. It is only used on small wrists.

The present invention enables a multi-jointed arm that is driven by wires and has a plurality of joints to have a lightweight and rigid structure by compactly incorporating the differential gear mechanism into the joints. A pair of cylindrical support parts each having both ends closed with end caps are provided oppositely at the tip of the arm on the proximal side, and the cylindrical support part is attached to an outer cylinder that is fitted onto the proximal end of the arm on the distal side. A cylindrical part is inserted between them with their central axes aligned with each other, and a mating ring for rotatably holding the cylindrical part and the cylindrical support part is fitted between the cylindrical part and the cylindrical support part. Wire pulleys that are rotatably driven by wires guided through the arms on the proximal end side are arranged inside the lids at both ends, and bevel gears are fixed to these wire pulleys, and bevel gears that mesh with both bevel gears are installed. , fixed to the proximal tube of the distal end arm rotatably fitted into the outer tube, thereby forming a differential gear mechanism, and cutting a wire insertion groove in the center of the cylindrical portion; , a wire insertion hole is provided in the center of the base end tube and the bevel gear fixed thereto, and these wire insertion grooves and wire insertion holes,
It is characterized by having a wire inserted through it to drive the joint on the distal end side.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 illustrates the overall configuration of a multi-jointed arm according to the present invention, in which a first arm 3 is rotatably driven by a motor 2 disposed inside a base 1. A second arm 5 is connected to the tip of the arm 3 through a joint 4, and third and fourth arms 7 and 9 are connected through joints 6 and 8. In each of the above-mentioned joints 4, 6, and 8, the distal arm rotates and bends relative to the proximal arm, and the drive is performed by a wire drive device (not shown), as described in detail below. This is carried out by pulling the wire led out through the wire insertion port 10 by means of (1). The tension of this wire is controlled by passing it through a coiled spring-shaped flexible tube 11 so that force can be transmitted even if the wire's path is bent during movement.

The joints 4, 6, and 8 all have the configuration shown in FIG. 2. That is, as clearly shown in FIG. 3, a pair of cylindrical support parts 12, 12 whose both ends are closed by end caps 13, 13 are provided at the tips of the arms on the proximal end side, and on the other hand, A cylindrical part 15 inserted between the pair of cylindrical support parts 12, 12 so that its axis coincides with the cylindrical support part is connected to the outer cylinder 14 which is fitted onto the base end of the arm on the distal side. A mating ring 1 is provided between the cylindrical part 15 and the cylindrical support parts 12, 12 to rotatably hold them.
7 and 17 are fitted, and a wire insertion groove 16 is cut in the center of the cylindrical portion 15.

Inside the end covers 13, 13 of the cylindrical support parts 12, 12, there is a wire pulley 1 rotatable around shafts 19, 19 supported by the end covers.
8, 18 are arranged, and these wire pulleys 18, 18
In this case, two wires 21 each led out from inside the proximal arm through the hole 20 and introduced into the inner side through the cylindrical support part 12 are wound in opposite directions, and their ends are It is fixed to the wire pulley. These wires 21 are inserted into flexible flexible tubes 11, and the tips of the flexible tubes 11 are each fixed to the cylindrical support part 12, and only the wires 21 are wound around the wire pulley 18 to receive the traction force. is transmitted.

Note that the engagement ring 17 can also be formed integrally with the wire pulley 18.

Further, both wire pulleys 18, 18 have bevel gears 2 rotating on shafts 19, 19, respectively.
2, 22 are fixed, and both bevel gears 2 are fixed.
The bevel gear 23 that meshes with the outer cylinder 14
It is fixed to the proximal tube 24 of the arm on the distal side, which is rotatably fitted into the tube, and these constitute a differential gear mechanism. Further, a wire insertion hole 25 is bored in the center of the base end tube 24 and the bevel gear 23.

In addition, in the figure, 26 and 26 indicate screws screwed onto the shaft ends for fixing the end caps 13 and stably supporting the shafts 19 and 19 with respect to the end caps, and 27 indicates a set screw. There is.

In the joint drive mechanism having the above configuration, when one of the two wires 21, 21 wound around the wire pulley 18 is pulled while the other is relaxed by driving the stepping motor or the like in the wire drive device, Wire pulley 18
rotates in either direction together with the bevel gear 22, the rotation is transmitted to the bevel gear 23 that meshes with the bevel gear 22, and the arm on the tip side is connected to the pair of wire pulleys 18,
It is rotated or bent depending on the manner of rotation of 18. That is, when the pair of wire pulleys 18, 18 are rotated in the same direction at the same speed, the bevel gear 23 meshed with them does not rotate, and the distal arm is bent at the joint, and the pair of wire pulleys When both wire pulleys 18, 18 are given relative rotation, such as when only one of the wire pulleys 18, 18 is rotated, or when they are rotated in opposite directions, the bevel gear 22 meshing with the bevel gears 22, 22 is rotated. As it rotates, the arm on the tip side will rotate.

According to the joint drive mechanism of the present invention, the housing of the joint is formed by the pair of cylindrical support parts provided at the tips of the proximal arms, and this housing is used as the member that bears the main load. This structure significantly increases rigidity and reduces weight. In addition, since each joint is driven by wire, the drive motor can be installed on the base side, which not only reduces weight, but also reduces the weight of the various parts that make up the multi-jointed arm. By forming it from plastic or aluminum within an allowable range in terms of strength, it is possible to further reduce the weight. Moreover, since the wires that drive the joints are inserted into each arm, and the sensor signal wires can also be inserted into each arm along with these wires, the device is advantageous in that it has a very compact appearance.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a multi-jointed arm according to the present invention, Fig. 2 is a sectional view showing details of the joint, and Fig. 3 is a sectional view with the differential gear mechanism etc. removed from the joint. It is. 3, 5, 7, 9... Arm, 12... Cylindrical support part,
13... End cover, 14... Outer cylinder, 15... Cylindrical part,
18... wire pulley, 21... wire, 22,
23...Bevel gear.

Claims (1)

[Claims] 1 A pair of cylindrical support parts each having both ends closed with end caps are installed at the tip of the arm on the proximal side, and a pair of cylindrical support parts are placed between the cylindrical support parts on the outer cylinder that fits over the proximal end of the arm on the distal side. A cylindrical part is inserted with the central axis aligned with the cylindrical part, and an engagement ring for rotatably holding the cylindrical part and the cylindrical support part is fitted between the cylindrical part and the cylindrical support part. A wire pulley that is rotationally driven by a wire guided through the arm on the proximal end side is arranged inside the arm, and bevel gears are fixed to these wire pulleys, and a bevel gear that meshes with both wire pulleys is installed.
fixed to the proximal tube of the distal end arm rotatably fitted into the outer tube, thereby forming a differential gear mechanism, and cutting a wire insertion groove in the center of the cylindrical portion; A multi-joint device characterized in that a wire insertion hole is provided in the center of the proximal tube and the bevel gear fixed thereto, and a wire for driving the distal joint is inserted through the wire insertion groove and the wire insertion hole. Joint drive device in the arm.