JPS6190893A - Robot joint - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a robot joint that performs spherical motion.

(Prior art and its problems) Conventionally, in order for the shaft end to move along an arbitrary trajectory on a spherical surface and to maintain the posture of the shaft end, as shown in FIG. It is common to achieve this by combining the rotation of the shaft B and the rotation of the third shaft C1c using a driving device such as a motor.

That is, the rotation A of the first shaft 1 and the second shaft 2 in FIG.
Due to B, the shaft end of the third shaft 3 moves along an arbitrary trajectory on the spherical surface, and due to the rotation C of the third shaft 3, the shaft end of the third shaft 3 maintains a posture. In order to indicate the attitude of the end of the third shaft 3, the third shaft 3 and the second shaft 2 are not rotated, but only the first shaft 1 is rotated to show the movement of the mark F attached to the tip of the third shaft 3. FIG. 9 shows a view from the direction on the first axis 1. In Figure 9, the dotted line is the mark F and the trajectory F' of the mark F when the first axis 1 rotates.
Indicates the status of Note that for the rotation of only the second axis 2, 8
If the rotation is until the g2 axis 2 is on a straight line with the first axis 1, the direction of the mark F will not change as shown in FIG. Next, in order to rotate each axis shown in FIG. 8 so as to maintain the posture of the mark F as shown in FIG. 10, it was necessary to also rotate the third axis 3.

However, in any structure, a rotating shaft with three degrees of freedom is required, and a driving device such as a motor is also required depending on the degree of freedom of the rotating shaft, which has the disadvantage of making the structure bulky and complicated.

(Object of the Invention) The object of the present invention is to eliminate such conventional drawbacks, and to provide a structure in which the shaft end moves along an arbitrary trajectory on a spherical surface in two degrees of freedom and maintains the posture of the shaft end. An object of the present invention is to provide a robot joint that is simple and compact.

(Structure of the Invention) The robot joint of the present invention has first and second rotating shafts that rotate, and the center line of the output shaft is at a constant angle with the center line of the first and second rotating shafts. a first drive unit in which one end of the first rotating shaft is attached to the main body and one end of the second rotating shaft is attached to the output shaft so as to intersect at one point; and the first rotating shaft is attached to the output shaft. a second driving part; and a joint means having one end that allows only rotational movement of the second rotating shaft and the other end of which is attached a main body of the second driving part. Ru.

(Detailed Description of Configuration) In the robot joint of the present invention, the center lines of the first and second rotation axes are always centered at the same intersection, and the length from the intersection to the end of the first rotation axis is the same. It is possible to move on an arbitrary trajectory on a spherical surface with a radius of , according to a velocity determined by the rotation speed of the first and second rotation axes, and an intersection angle and an azimuth determined by the rotation angle. Further, the orbit length on the spherical surface of the shaft end, in other words, the intersection angle where the two rotation axes intersect and the azimuth indicating the direction can be determined depending on the rotation angle of the two rotation axes.

(Example) The present invention will be described below with reference to all drawings showing examples.

FIG. 1 is a detailed illustration of the present invention, and is a perspective view of the central portion of an embodiment of the present invention. Two rotating shafts 4, 5
The rotating shaft 4 is connected to the frame of the motor 6 by using a connecting part 40 to the output shaft of the motor 6. 5 are each attached at a certain angle. FIG. 2 is a sectional view of FIG. 1. Two rotating shafts 4, 5
The center lines 4C and 5C of the motor 6 always intersect at the intersection P, and the center line 6C of the motor 6 also intersects at the same intersection P, and the center lines 6C and 4C and the center lines 6C and 5C always have a constant angle a. . As is clear from FIG. 2, the rotation axis 4 is set at an angle a'z such that the center line 6C of the motor rotor 61 of the motor 6 and the center line 4C of the rotation axis 4 always intersect with the intersection P.
The connecting part 40 is used to attach the motor 6 at an angle so that the stator 62 of the motor 6 is attached to the rotary shaft 5 at an angle.
It is directly attached to the motor 6 at an angle a such that the center line 5C of the rotating shaft 5 intersects at the intersection P. Therefore, the center lines 4C and 50 always intersect at the intersection P, even when they are located on a straight line passing through the intersection P.

The motor rotor 61 and motor stator 62 of the motor 6 are coupled by a coupling means such as a bearing 63, and the principle is the same even when using a reduction gear due to problems such as this structure and torque. It can be inferred that the detailed explanation will be omitted.

FIG. 3 is a front view of an embodiment of the present invention using the motor 6 shown in FIGS. 1 and 2. FIG. Referring to FIG. 3, the rotating shaft 4 is connected to the universal joint 7 through a bearing 8, the rotating shaft 5 is connected to the output shaft 90 of the motor 9, which is the other drive part, and the motor 9 itself is connected to the universal joint 7. join directly to.

In such a configuration, when the motors 6 and 9 are rotated appropriately, the tip of the rotating shaft 4 moves around the intersection P with respect to the rotating shaft 5, as shown in FIGS. 4 and 5. That is, the tip of the universal joint 7 can point at any intersection angle and azimuth with respect to the motor 9.

FIG. 6 shows the locus 100 of the tip of the rotating shaft 4 when only the motor 6 is rotated from the state shown in FIG.
It is a diagram shown on a coordinate axis of xr 7 +2 with a locus 110 of the tip of the intersection point 1 as the origin and the direction of the rotation axis 5 as the second axis. In this way, the locus 100° 110 when each motor 6.9 is rotated independently becomes symmetrical with respect to the Z axis.

Furthermore, FIG. 7 shows the trajectory of the basic movement of the tip of the rotating shaft 4 when the two motors 6.9 are rotated simultaneously. Locus 120 when the motors 6 and 91fr are rotated in opposite directions by the same rotation angle on the rotation axis 4.5,
Motor 6.9 each with rotating shaft 4. This is the trajectory 130 when rotated in the same direction by the same rotation angle at 5°.The trajectory 120 always moves to intersect with the two axes regardless of the azimuth angle, and the trajectory 130 is parallel to the x-y coordinate plane and Operates around two axes. Two basic trajectories 12 shown in this Figure 7
0 and 130), the tip of the rotating shaft 4 can be easily tilted arbitrarily with respect to the two axes.

(Effects of the Invention) As explained above, the present invention has the advantage that the tip of the rotating shaft can be easily tilted arbitrarily with two degrees of freedom. Furthermore, one of the two motors that serve as the drive unit can be incorporated into the universal joint that serves as the coupling means, and the motor only needs to drive the transmission shaft without being directly affected by its own weight, resulting in highly efficient operation. The structure is simple, and robot joints can be easily made smaller and lighter.

[Brief explanation of the drawing]

1 and 2 are perspective views and cross-sectional views of the central portion of an embodiment of the present invention, and FIGS. 3 to 5 are front views of an embodiment of the present invention using the central portion shown in FIG. 1. 6 and 7 are diagrams showing the basic operation locus of the embodiment shown in FIG. 3. FIG. 8 is a perspective view of a conventional robot joint, FIG. 9 and FIG. 8 is a plan view showing the basic motion of the robot joint shown in FIG. 8, in which only the first axis 1 is rotated and the third axis 3 is also rotated to maintain the posture of the end of the third axis 3. FIG. 1...First axis, 2...Second axis, 3...
...3rd axis, 4.5...rotation axis, 6,9.
...Motor, 40...Connection parts, 7...
... Universal joint, 8 ... Bearing, 90 ... Output shaft of motor 9. 2nd leap

Claims (1)

[Claims] The first rotating shaft and the second rotating shaft, and the first rotating shaft such that the center line of the output shaft intersects the center line of the first and second rotating shaft at one point at a certain angle. A first shaft having one end attached to the main body and one end of the second rotating shaft attached to the output shaft.
a second drive unit having the first rotation shaft attached to an output shaft; a second drive unit having the second rotation shaft attached to one end so as to allow only rotational movement; and the second drive unit having the second rotation shaft attached to the other end, and a joint means attached to the body of the robot joint.