JPH0453913Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to the structure of the wrist portion of a manipulator.

B. Summary of the invention The present invention is to attach a joint ring rotatably to the inner side of the wrist intermediate shaft on the arm side in the wrist of a flexible manipulator in which an operating shaft is supported inside, and to attach the joint ring to the inside of the wrist intermediate shaft on the arm side. The structure of the wrist part is simplified by attaching the wrist shaft on the hand side to the inside so that it can rotate freely in a direction perpendicular to the rotation direction of the joint ring, and by supporting the operating shaft inside the wrist shaft. This also aims to improve the transmission efficiency of the operating shaft.

C. Prior Art Conventionally, robot-type and fixed-type manipulators have been used for work in adverse environments, work with hazardous materials, or work in narrow spaces where workers cannot directly enter. They also perform detailed and complex tasks.

In the structure of this manipulator, the shoulder and arm portions are not close to the object being handled.
Although a relatively large size is allowed, the wrist and the hand beyond it are required to be smaller in order to obtain good workability. However, if a power source for the wrist or hand is disposed at these joints, there is a problem in that the joints become large and the degree of freedom is restricted. On the other hand, a wire drive method can be considered in which the wrist and hand are driven by passing a flexible drive wire from the arm to the wrist, but although this can prevent the wire from becoming too large, it may cause the wire to stretch or become loose. This has the disadvantage that the movement of the wrist and hand becomes uncertain because of the ease of movement.

Therefore, in order to eliminate these shortcomings,
For example, a manipulator as shown in Japanese Unexamined Patent Publication No. 182093/1983 has been proposed.

FIG. 4 shows a cross-sectional view of this conventional manipulator. In FIG. 4, a rotating frame 13 is attached to the tip of the arm tube 11 so as to be tiltable in any direction, and a plurality of wrist bending linear actuators 1 are arranged in the arm tube 11 in the circumferential direction.
5 (only one is shown in the figure) are connected to the rotating frame 13 via rods 17, and the rotating frame 13 can be driven in any direction by these linear actuators 15. This rotating frame 1
3, a hollow wrist intermediate shaft 19 is rotatably supported via a bearing 21. The outer periphery of the distal end of the wrist intermediate shaft 19 is spherical, and a hemispherical joint fitting 23 is slidably attached thereto and connected by a pair of pivot pins 25. Furthermore, a hollow wrist shaft 27 whose proximal inner surface is a concave spherical surface is slidably attached to the outer periphery of the joint fitting 23.
These joint fittings 23 and the wrist shaft 27 are connected by a pair of pivot pins 29 disposed in a direction orthogonal to the pivot pin 25. Therefore, the joint fitting 23 and the pivot pins 25, 29 constitute a universal joint, and the wrist intermediate shaft 19 and the wrist shaft 27 can be bent in any direction while simultaneously rotating. Further, a hand 33 having a fingertip member 31 that opens and closes is provided at the tip of the wrist shaft 27.

On the other hand, a hollow rotary drive shaft 35 is rotatably supported in the center of the arm tube 11 via a bearing 37.
A reduction gear 39 is fixed to the base end of the rotary drive shaft 35, and the reduction gear 39 is connected to the gear 4 of a drive motor 41 for rotating the hand disposed inside the arm barrel 11.
It meshes with 3. Further, an annular joint fitting 45 is connected to the inside of the tip end of the rotational drive shaft 35 by a pair of pivot pins 47, and furthermore, this joint fitting 4
5 is connected to the proximal end of the wrist intermediate shaft 19 by a pair of pivot pins 49 disposed in a direction orthogonal to the pivot pins 47 . That is, the rotary drive shaft 35 and the wrist intermediate shaft 19 are connected by a universal joint made up of a joint fitting 45 and pivot pins 47 and 49, and both can be bent in any direction while simultaneously rotating. It is becoming. Therefore, when the hand rotation drive motor 41 is rotated, the rotary drive shaft 35 rotates at a reduced speed, and the rotation is transmitted to the wrist shaft 27 via the wrist intermediate shaft 19.
Rotate the hand 33.

Furthermore, an opening/closing drive shaft 51 is rotatably supported coaxially with the rotating drive shaft 35 via a bearing 53, and a finger opening/closing shaft 51 fixed to the reduction gear 39 is attached to the base end of the opening/closing drive shaft 51. The shaft 57 of the drive motor 55 is spline fitted. Also,
The distal end side of the opening/closing drive shaft 51 is supported by the joint fitting 45 through a spherical bushing 59 at its intermediate portion, and the operating shaft 6 is connected to the distal end through a universal joint 61.
3 are connected. The operating shaft 63 has an inner shaft 63b fitted into an outer shaft 63a by spline fitting or the like so as to be slidable in the axial direction, and is expandable and retractable in the axial direction. A spherical bushing 65 is attached to the outer periphery of the outer shaft 63a of the operation shaft 63 so as to be slidable in the axial direction.
It is held so that it can slide in all directions inside a ring 67 that is fixed inside. In addition, the inner shaft 63b of the operation shaft 63 is connected to the wrist shaft 27 via a bearing 69.
The tip of the worm 71 is spline-fitted to the worm 71 which is supported by the hand 33. Therefore, when the finger opening/closing drive motor 55 is rotated, the worm 71 is rotated via the opening/closing drive shaft 51 and the operation shaft 63.

In the hand 33, each of the pair of fingertip members 31 is rotatably attached to the tips of two sets of parallel links 73, and the base ends of the two sets of parallel links 73 are rotatably attached to the hand 33. The inner links are each fixed to a worm wheel 75 that meshes with the worm 71. Therefore, when the worm 71 rotates, both fingertip members 31
move toward and away from each other while maintaining a parallel relationship.

In such a manipulator, a power source disposed in the arm tube 11 is used to bend the wrist and control the hand 33.
The rotation of the fingertip member 31 and the opening and closing of the fingertip member 31 can be performed independently, and since a universal joint is used for power transmission without using a wire, reliable operation can be achieved.

D. Problems to be Solved by the Invention However, in the wrist portion of the conventional manipulator described above, the operation shaft 63 is supported inside the wrist intermediate shaft 19 via the spherical bush 65, and the operation shaft 63 is supported on the outside of the wrist intermediate shaft 19. Since the wrist shafts 27 are connected via a universal joint, the following problems arose.

(1) Since the spherical bush 65 and the universal joint coexist in the wrist, the structure becomes complicated.

(2) Since the operating shaft 63 is supported by the spherical bush 65, power transmission efficiency is poor.

The present invention solves these problems in the structure of the wrist of a conventional manipulator, and aims to provide a wrist structure of a manipulator that has a simple structure and improves the transmission efficiency of the operating shaft. .

E. Means for Solving Problems To achieve this objective, the wrist structure of the manipulator according to the present invention connects an arm and a hand, and an operating shaft for operating the hand is supported inside. In the wrist structure of the manipulator, a rotating frame is provided at the tip of the arm and can be bent in any direction by a bending driving means provided in the arm, and a hollow wrist intermediate shaft is rotatably mounted on the rotating frame. and connecting the wrist intermediate shaft to a hand rotation drive means provided in the arm via a universal joint,
A joint ring is rotatably attached to the inner side of the wrist intermediate shaft by a first pivot pin, and the wrist side connected to the hand side is placed inside the joint ring and perpendicular to the first pivot pin. The operation shaft is rotatably mounted by a second pivot pin arranged in the direction, and the operating shaft is connected to the front shaft part connected to the operated part of the hand, and rotates integrally with this front shaft part, and and a rear shaft part that is slidable in the axial direction with respect to the wrist shaft, the rear shaft part of the operating shaft is supported inside the wrist shaft, and the rear shaft part of the operating shaft is supported by the rear shaft part of the operating shaft. It is characterized by being connected via a universal joint to a hand drive means provided in the arm.

F Function A universal joint is constituted by the joint ring and the first and second pivot pins, and the wrist intermediate shaft and wrist shaft can be bent in any direction while simultaneously rotating. The wrist shaft is located at the innermost position in relation to the wrist intermediate shaft and the joint ring, and therefore the operating shaft located inside the wrist is directly supported by the wrist shaft, eliminating the need for a special spherical bushing to support the operating shaft. Become.

G. Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a manipulator according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG.
FIG. 3 is a sectional view of the manipulator in a state where the wrist is bent. In the following description, the same parts in FIGS. 1 and 3 as in the conventional manipulator shown in FIG. 4 are designated by the same reference numerals, and redundant explanation will be omitted.

As shown in FIG.
1, a hollow wrist intermediate shaft 77 is rotatably supported. The proximal end of the wrist intermediate shaft 77 is connected to the rotary drive shaft 35 via a universal joint comprised of a joint fitting 45 and pivot pins 47 and 49, as in the conventional case. A joint ring 81 is rotatably attached to the inner side of the wrist intermediate shaft 77 by a pair of first pivot pins 79 . At the contact surfaces between the wrist intermediate shaft 77 and the joint ring 81, in order to prevent interference due to rotation, the inner peripheral surface of the wrist intermediate shaft 77 is a cylindrical surface, and the outer peripheral surface of the joint ring 81 is a spherical surface. . moreover,
Inside the joint ring 81, a wrist shaft 83 has a pair of second
It is rotatably attached by a pivot pin 85.
As shown in FIG. 2, the second pivot pin 85 is disposed in a direction perpendicular to the first pivot pin 79, so that the wrist intermediate shaft 77 and the wrist shaft 83 are The ring 81 and the first and second pivot pins 79 and 85 are connected via a universal joint. Similarly, in order to prevent interference due to rotation at the contact surface between the joint ring 81 and the wrist shaft 83, the inner peripheral surface of the joint ring 81 is made into a cylindrical surface, and the outer peripheral surface of the wrist shaft 83 is made into a spherical surface. .

Further, inside the wrist shaft 83, an outer shaft 87a, which is a rear shaft portion of an operation shaft 87 connected to the opening/closing drive shaft 51 via a universal joint 61, has a needle bearing 87a.
9. On the other hand, the hand 33 is attached to the tip of the wrist shaft 83, and the tip of the inner shaft 87b, which is the front shaft portion of the operation shaft 87, is attached to the fingertip member 31.
It is connected to a worm 71 that drives the opening/closing. In other words, the operating shaft 87 of this embodiment is composed of an outer shaft 87a provided with the universal joint 61, and an inner shaft 87b spline-fitted to the outer shaft 87a and connected to the worm 71. Only the rotational force from the shaft 87a is transmitted to the inner shaft 87b, allowing relative movement between the outer shaft 87a and the inner shaft 87b along the left-right direction in FIG.

In such a configuration, when the rotating frame 13 is tilted by the linear actuator 15 for wrist bending, which is a bending drive means, the wrist is bent, as in the conventional case. That is, as shown in FIG. 3, when the swing frame 13 tilts, the wrist intermediate shaft 77 also tilts, and furthermore, even if the swing frame 13 tilts, the position of the universal joint 61 does not change, so that the operating shaft 87
extends and tilts, causing the wrist axis 83 to tilt with respect to the wrist intermediate axis 77, thereby bending the wrist. Also,
The entire hand 33 rotates via the wrist intermediate shaft 77 and the wrist shaft 83 by the operation of the drive motor 41, which is a drive means for hand rotation, while the drive motor 55 for opening and closing fingers, which is a drive means for the hand, rotates the entire hand 33. The worm 71 rotates via the operating shaft 87, and the fingertip member 31 opens and closes. Here, the operation shaft 87 has a needle bearing 8 which is a rolling bearing on the wrist shaft 83.
9, the support resistance at that portion is small, and the power transmission efficiency of the operating shaft can be improved.

H. Effects of the invention As described above in detail with reference to one embodiment, according to the invention, there is no need for a special spherical bushing in the wrist of the manipulator to support the operating shaft within the wrist shaft. The structure of the wrist part is simplified, improving accuracy and reducing manufacturing costs. Furthermore, since the structure is simple, the diameter of the operating shaft can be increased by keeping the same external dimensions as conventional ones, and the strength can be improved. Furthermore, since the operating shaft can be supported by a rolling bearing relative to the wrist shaft, it is possible to improve the power transmission efficiency of the operating shaft.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a manipulator according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG.
FIG. 3 is a sectional view of the manipulator in a state where the wrist is bent, and FIG. 4 is a sectional view of a conventional manipulator. In the drawing, 11 is an arm barrel, 13 is a rotating frame, 15 is a linear actuator for bending the wrist, 33 is a hand,
41 is a hand rotation drive motor, 55 is a finger opening/closing drive motor, 77 is a wrist intermediate shaft, 79 is a first pivot pin, 81 is a joint ring, 83 is a wrist shaft, and 85 is a second pivot pin. , 87 are operating axes.

Claims (1)

[Scope of utility model registration request] In a wrist structure of a manipulator that connects an arm and a hand, and in which an operating shaft for operating the hand is supported, the tip of the arm is bent in any direction by a bending drive means provided in the arm. a rotating frame that can be bent and moved; a hollow wrist intermediate shaft is rotatably provided on the rotating frame; and the wrist intermediate shaft is connected to a hand rotation driving means provided in the arm via a universal joint; A joint ring is rotatably attached to the inner side of the wrist intermediate shaft by a first pivot pin, and the wrist shaft connected to the hand side is placed inside the joint ring and perpendicular to the first pivot pin. The operation shaft is rotatably mounted by a second pivot pin arranged in the direction, and the operating shaft is connected to the front shaft part connected to the operated part of the hand, and rotates integrally with this front shaft part, and and a rear shaft part that is slidable in the axial direction with respect to the wrist shaft, the rear shaft part of the operating shaft is supported inside the wrist shaft, and the rear shaft part of the operating shaft is supported by the rear shaft part of the operating shaft. A wrist structure for a manipulator, characterized in that it is connected via a universal joint to a hand drive means provided in the arm.