JPH11210740A - Universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and enlarge a motion angle by providing an intermediate body connected relative-rotatably around a first rotary axis for a joint fixing part and an output body connected relative-rotatably around a second rotary axis crossing with the first rotary axis for the intermediate body. SOLUTION: By the relative rotation of an output body 9 for an intermediate body 3 around the rotary axis ω slanted by a prescribed angle for a rotary axis ϕ, an angle γ is generated between the rotary axis ϕ for the joint fixing part 1 of the intermediate body 3 and the axis χ of the output body 9, in response to the rotary angle β for the intermediate body 3 of the output body 9. By the relative rotation for the intermediate body 3 of the output body 9, the axis χ is rotated around the rotary axis ω while always maintaining a prescribed angle between the center shaft and rotary axis ω. As the intermediate body 3 can be relatively rotated for the joint fixing part 1, if the angle made by the rotary axis ω and axis χ is 30 deg., the motion angle range of the output body 9 becomes 60 deg. at one side. Therefore, the motion angle can be enlarged and the joint can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint mainly used for a manipulator and having two or more degrees of freedom.

[0002]

2. Description of the Related Art For example, as a universal joint for connecting both ends of a link connecting an actuator and a movable portion of a manipulator and an actuator and a movable portion, Japanese Patent Application Laid-Open No. Hei 7-158655 discloses a cross-shaped shaft. It consists of a pair of yokes that support opposite shafts,
It is disclosed that each yoke can rotate around a supported axis.

Japanese Patent Application Laid-Open No. Hei 6-341450 discloses a sphere having two grooves and a pair of yokes for supporting the sphere along the groove. It is described that it can rotate around. Further, JP-A-8-152018 discloses that
There is disclosed a ball joint that includes a holder portion that covers the ball, and the ball can freely rotate inside the holder portion.

By the way, when such a universal joint is used for a parallel manipulator, the joint is small and light in order to realize a high-speed operation of the manipulator, and in order to widen the operating range of the manipulator,
Preferably, the joint has a wide operating angle.

However, in the above-mentioned conventional universal joint, the operating angle is determined by the interference between one yoke and the other yoke. Therefore, in order to increase the operating angle, it is necessary to enlarge the cross axis or the sphere. However, there is a problem that the size of the joint is inevitably increased.

Further, the conventional ball joint has a structure in which the holder wraps the ball so that the ball does not fall out of the holder, so that the operating angle is narrow, and there is a limit to widening the operating angle.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a universal joint which solves the above problems.

[0008]

According to a first aspect of the present invention, there is provided a joint fixing portion,
An intermediate member connected to the joint fixing portion so as to be relatively rotatable about a first rotation axis; and an intermediate member intersecting the first rotation axis with respect to the intermediate member about a second rotation axis. A universal joint comprising an output body rotatably connected.

Further, in claim 2 of the present invention,
By rotating the output body relative to the intermediate body, a third rotation axis that swings about an intersection between the first rotation axis and the second rotation axis is centered on the output body. The universal joint according to claim 1, further comprising an operation body connected to be relatively rotatable.

According to a third aspect of the present invention, the joint fixing portion and the intermediate member, and the intermediate member and the output member are connected via a ball bearing. The universal joint described in Item 1 was used.

According to a fourth aspect of the present invention, the joint fixing portion and the intermediate member, the intermediate member and the output member, and the output member and the operation member are connected via a ball bearing. The universal joint according to claim 2 is characterized in that:

According to the universal joint described in the first aspect, the intermediate member rotates relative to the joint fixing portion, and the output member rotates relative to the intermediate member. can do.

Further, according to the universal joint according to the second aspect of the present invention, the universal joint having three degrees of freedom can be obtained by further rotating the operating body relative to the output body.

According to the universal joint of the third aspect, since the joint fixing portion and the intermediate member, and the intermediate member and the output member are connected via the ball bearing, each of the joint members is relatively free from resistance. Can rotate.

According to the universal joint described in the fourth aspect, the joint fixing portion and the intermediate body, the intermediate body and the output body, and the output body and the operation body are connected via the ball bearing. Therefore, each can rotate relatively without resistance.

[0016]

FIG. 1 is an external view of a first embodiment of a universal joint according to the present invention, and FIG. 2 is a sectional view of FIG. In the figure, joint fixing part 1
Has a plurality of mounting holes 1a, and is fixed to, for example, an actuator or a movable body side of a manipulator (not shown) through the mounting holes 1a. Further, as shown in FIG. 2, the joint fixing portion 1 is provided with a concave portion 1b.

The intermediate body 3 is provided with a projection 3a directed downward, and the projection 3a is
b, the inner race 5a of the ball bearing 5 is inserted into an engagement groove 3aa provided on the outer peripheral portion of the projection 3a.
On the other hand, the outer race 5b rotatable with respect to the inner race 5a via the ball 5c of the ball bearing 5 is fitted into the engagement groove 1ba provided on the inner wall of the concave portion 1b of the joint fixing portion 1. Fitted and installed. Thus, the intermediate body 3 is connected to the joint fixing portion 1 via the ball bearing 5 so as to be relatively rotatable about the rotation axis ψ.

The upper surface of the intermediate body 3 has a slope inclined to the right as shown in the figure, and a projection 3b is provided at the center thereof. The lower surface of the output body 9 is also a slope inclined rightward as shown in the figure, and has a recess 9a at the center thereof. In the recess 9a of the output body 9,
The protruding portion 3b of the intermediate body 3 is arranged, and the inner race 7a of another ball bearing 7 is fitted to the outer peripheral portion thereof. Outer race 7b installed relative to inner race 7a via ball 7c
Is fitted to the inner wall of the concave portion 9a of the output body 9. As a result, the output body 9 is inclined at a predetermined angle with respect to the rotation axis ψ with respect to the rotation axis ψ with respect to the intermediate body 3 via the ball bearing 7, so that the rotation axis ω intersects the rotation axis ψ at the intersection 11. As a result, the present configuration functions as a universal joint having two degrees of freedom.

A sleeve portion 9b is provided on the upper portion of the output member 9, and a link 13 is fitted in the sleeve portion 9b and fastened by a plurality of screws 15. The distal end of the link 13 is connected to, for example, a movable body of a manipulator (not shown) or an actuator.

FIG. 3 shows the operation of the above-described universal joint having two degrees of freedom. As described above, the output body 9 rotates relative to the intermediate body 3 about the rotation axis ω inclined at a predetermined angle with respect to the rotation axis ψ,
According to the rotation angle β of the output body 9 with respect to the intermediate body 3, an angle γ is generated between the rotation axis ψ of the intermediate body 3 with respect to the joint fixing portion 1 and the center axis χ of the output body 9. That is, the relative rotation of the output body 9 with respect to the intermediate body 3 causes the center axis χ of the output body 9 to rotate around the rotation axis ω while always maintaining a predetermined angle with the rotation axis ω.

As described above, since the intermediate member 3 can rotate relative to the joint fixing portion 1, as shown in FIG. 4, the angle (the angle between the rotation axis ω and the central axis χ of the output member 9) If the angle between the rotation axis ψ and the rotation axis ω is equal to 30 °, the operating angle range of the output body 9 is 6
0 °.

FIG. 5 shows a second embodiment of the universal joint according to the present invention. What is described in FIG. 5 is different from the aforementioned universal joint,
The point is that the link 11 connected to the output body 9 extends so as to be orthogonal to the rotation axis ω.

FIG. 6 shows a third embodiment of the universal joint according to the present invention. In the third embodiment, the operation body 17 is relatively rotatable via the ball bearing 19 with respect to the output body 15 which is rotatably connected to the intermediate body 3 via the ball bearing 7. Connected. The operating body 17 is rotatable about its central axis χ as a rotation axis. Thus, the universal joint according to the third embodiment has three degrees of freedom.

According to the operation of the universal joint of the present invention, the operating angle can be increased without the joint support, the intermediate body, and the output body interfering with each other.
As a result, the size of the universal joint itself can be reduced.

The universal joint according to the present invention
The present invention is not limited to those used for manipulators, but can be used for various mechanical equipment.

[0026]

As described above, according to the present invention, the operating angle can be increased without causing the joint support, the intermediate body and the output body to interfere with each other at the time of operation. Can be downsized.

Further, since the joint support, the intermediate body, and the output body are connected to each other via the ball bearing, the resistance between them during operation can be minimized.

[Brief description of the drawings]

FIG. 1 is an external view of a universal joint according to a first embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a diagram showing the operation of the universal joint according to the first embodiment of the present invention.

FIG. 4 is a view for explaining an operating angle of a universal joint according to the present invention.

FIG. 5 is an external view of a universal joint according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a universal joint according to a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Joint fixed part 3 Intermediate body 9, 15 Output body 17 Operation body 5, 7, 19 Ball bearing ψ, ω Rotation axis

Claims (4)

[Claims] 1. A joint fixing portion, an intermediate member connected to the joint fixing portion so as to be relatively rotatable about a first rotation axis, and an intersection of the intermediate member with the first rotation axis. A universal joint, comprising: an output member connected so as to be relatively rotatable about a second rotation axis. 2. The method according to claim 1, further comprising: rotating the output member relative to the intermediate member to thereby rotate the first rotation shaft and the second rotation member.
The universal joint according to claim 1, further comprising an operation body connected to the output body so as to be rotatable relative to the output body around a third rotation shaft that swings and rotates around an intersection with the rotation shaft. . 3. The universal joint according to claim 1, wherein the joint fixing portion and the intermediate member, and the intermediate member and the output member are connected via a ball bearing. 4. The apparatus according to claim 1, wherein the joint fixing portion and the intermediate body, the intermediate body and the output body, and the output body and the operation body are connected via a ball bearing. 2. The universal joint according to 2.