JPH04240090A - Rotation control device - Google Patents

Abstract

PURPOSE:To allow a rotary shaft to rotate over 360 deg. and restrict the overrun and sense an eventual occurrence of overrunning using a rotation control device by equipping it with a function that an overrun sensor senses going-out of overrun state immediately when the rotary shaft condition is restituted. CONSTITUTION:A rotary shaft 4 pushes a follower dog 20 clockwise with a prime mover dog 14, and the follower dog 20 stops upon deforming a stopper 30 of rubber etc., which functions also as a repulsing means, and a sensor 38 senses that the rotary shaft 4 has overrun. From this time, the rotary shaft can continue rotating till the time when the rotary shaft 4 pushes the follower dog 20 counterclockwise with the prime mover dog 14, and the follower dog 20 stops upon deforming the stopper 30, and then a sensor 39 senses overrun of the rotary shaft 4. When the rotary shaft 4 and prime mover dog 14 reverse from the overrun state, the stopper 30 functioning also as repulsing means push back the follower dog 20 at once, and the sensors 38, 39 are restituterd.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control device for controlling the rotation of a rotation shaft such as a joint of an industrial robot.

0003

2. Description of the Related Art A conventional rotation control device of this kind, disclosed in Japanese Patent Application Laid-Open No. 2-185390, has a rotation shaft that can rotate more than 360 degrees, and furthermore, has a It is possible to detect a rotation of the rotation axis exceeding the range, that is, an overrun, and also to restrict the overrun of the rotation axis with a stopper.

However, in this device, the driving dog (first protrusion) provided on the rotating shaft causes the driven dogs (rotating body and dogs) around the rotating shaft to follow the rotation of the rotating shaft with a delay. By rotating and detecting the rotation of this driven dog (rotating body and dog) with a sensor (proximity switch),
Since the overrun of the rotation axis is detected, even if the rotation axis that is in the overrun state is reversed and the rotation axis is restored from the overrun state, the driven dog (rotating body and dog) will be damaged immediately. Since the sensor (proximity switch) does not move, the sensor (proximity switch) remains in the state of detecting overrun for a while until the rotation axis returns to the angle of the delayed rotation described above.
It does not detect that it is no longer in an overrun state.

[0005]

[Problems to be Solved by the Invention] As mentioned above, in the conventional rotation control device that can rotate more than 360 degrees, even if the rotation axis returns from the overrun state, the overrun detection sensor does not overrun. There was a problem in that the run detection state was not released immediately.

The present invention has been made in view of the above points, and provides a rotation control device in which a rotation shaft can rotate over 360 degrees, and is capable of overrun detection and overrun regulation of the rotation shaft. The purpose of this is to immediately cause the overrun detection sensor to detect that the overrun state is no longer present when the rotating shaft returns from the overrun state.

[Configuration of the invention]

[0008]

[Means for Solving the Problems] The present invention relates to a rotation control device 1 for controlling the rotation of a rotation shaft 4 with respect to a base 8. A driving dog 14 that rotates together with the driving shaft 4, a driven dog 20 that is rotatably provided on the rotating shaft 4 and rotatably engaged with the driving dog 14 within a predetermined range, and a driven dog 20 that is provided on the base 8. a stopper 30 that restricts the rotation range of the driven dog 20; a repulsive means 30 that applies a repulsive force to push the driven dog 20 back against the driven dog 20 when the stopper 30 and the driven dog 20 come into contact; It is equipped with sensors 38 and 39 that detect when the driven dog 20 abuts against the stopper 30 against the repulsive force of the repulsive means 30.

According to a second aspect of the present invention, in the rotation control device 1 of the first aspect, resistance is generated between at least one of the rotation shaft 4 and the driving dog 14 and the driven dog 20.
An interlocking means 27 for passively rotating the rotation shaft 4 together with the rotation shaft 4 is added.

0010

[Operation] In the rotation control device 1 of the present invention, the rotation shaft 4 pushes the driven dog 20 clockwise via the driving dog 14, so that the driven dog 20 comes into contact with the stopper 30, and the rotation shaft 4 pushes the driven dog 20 clockwise.
When the sensor 38 detects a clockwise overrun of The rotation shaft 4 can be rotated within the range up to the state where the sensor 39 detects the counterclockwise overrun of the rotation shaft 4, and when the rotation shaft 4 and the driving dog 14 are reversed from the overrun state, the repulsion occurs immediately. Means 3
0 pushes back the driven dog 20 and detects that the sensors 38 and 39 are no longer in the overrun state.

In addition to this, according to the second aspect of the present invention, the driven dog 20 follows the rotation of the driving dog 14, and does not move unstablely.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the rotation control device of the present invention will be described with reference to the drawings.

FIGS. 1 to 5 show a rotation control device 1,
This rotation control device 1 is provided at the tip of a multi-joint arm mechanism 2 that can be bent and rotated in the vertical direction of a vertically articulated robot shown in FIG. A rotating shaft 4 that projects perpendicularly to the rotating shaft 4 rotates, and a transfer cargo holding device or the like is attached to a flange 5 provided at the bottom of the rotating shaft 4.

The multi-joint arm mechanism 2 always maintains the rotation control device 1 in the same posture, thereby controlling the rotation axis 4.
always remains vertical.

The rotation control device 1 has a base 8 rotatably supported in the vertical direction at the distal end of the multi-joint arm mechanism 2. As shown in FIG. 5, the base 8 is composed of a cylindrical case 9 and a ring-shaped plate 10 attached to the lower end of the case 9. An outer ring 11 is held, and the upper end of the rotation shaft 4 is supported by the bearing 11 so as to be rotatable vertically and horizontally at the lower part of the base 8.

The motor 3 shown in FIG. 6 is provided on the upper part of the case 9, and a reducer (not shown) is provided inside the case 9, so that the rotation of the motor 3 is decelerated and then rotated. It is designed to be transmitted to the moving axis 4.

A ring-shaped driving dog 14 is attached to the outer periphery of the upper end of the rotating shaft 4. As shown in FIGS. 1 to 4, this motive dog 14 has an arcuate ridge 15 protruding downward from its outer periphery.
Both end portions 16 and 17 of 5 are projecting pieces 2 of a driven dog 20, which will be described later.
This serves as an engaging part for both side parts of 4.

The inner ring of the bearing 11 is fixed to the upper end of the rotating shaft 4 by the driving dog 14.

Further, a driven dog 20 is rotatably attached to the outer periphery of the rotating shaft 4 by a nut 23 via a pair of upper and lower ball bearings 21 and 22, located below the driving dog 14. As shown in FIGS. 1 to 4, this driven dog 20 has a projecting piece 24 protruding from its outer periphery.
The rotation range of the driven dog 20 with respect to the driving dog 14 is restricted by this protruding piece 24 and the arc-shaped protruding edge 15 of the driving dog 14 . That is, the driven dog 20 moves from a state in which its protruding piece 24 is in contact with one end 16 of the projecting edge 15 of the driving dog 14 to a state in which it is in contact with the other end 17 of the projecting edge 15.
It is designed to rotate within a range of 180 degrees relative to the motive dog 14.

The rotation range of the driven dog 20 with respect to the driving dog 14 can be set arbitrarily within less than 360 degrees.

The bearings 21 and 22 and the nut 23 on which the driven dog 20 is attached to the rotating shaft 4 constitute interlocking means 27 for interlocking the driven dog 20 with the rotating shaft 4,
By tightening the inner ring of the bearing 22 with this nut 23, the inner ring and outer ring of each bearing 21, 22 obliquely tighten and press the ball between them, and each bearing 21,
Mechanical resistance is generated at 22, which causes rotational axis 4
At the time of rotation, the driven dog 20 rotates in a driven manner due to the resistance of each bearing 21, 22.

Further, a stopper 30 made of an elastic material such as urethane rubber is attached to the lower surface of the plate 10 of the base 8 with a screw 32 through a spacer 31, and the rotation range of the driven dog 20 is regulated by this stopper 30. ing. That is, as shown in FIG. 3, the driven dog 20 changes from a state in which its projecting piece 24 abuts one end 33 of the stopper 30 and crushes this end 33 to elastically deform it.
As shown in FIG. 4, the protruding piece 24 contacts the other end 34 of the stopper 30 and rotates through a range of about 270 degrees until the other end 34 is crushed and elastically deformed. It is supposed to be done.

Note that the rotation range of the driven dog 20 is 36
It can be set arbitrarily below 0 degrees.

[0024] This stopper 30 is connected to the driven dog 2.
It also serves as a repulsion means to push back the 0, as shown in Figure 3 or Figure 4.
As shown in FIG. 2, when one end 33 or the other end 34 of the driven dog 20 is elastically deformed due to contact with the driven dog 20, the restoring force due to the elasticity acts as a repulsive force pushing back the driven dog 20. ing.

A control box 37 is provided on one side of the case 9 of the base 8, and limit switches 38, 3 as a pair of sensors are provided on the bottom surface of the control box 37.
9 is provided, and one limit switch 38 is such that the protruding piece 24 of the driven dog 20 is connected to the stopper 30 as shown in FIG.
The other limit switch 39 detects the state in which the one end 33 is in contact with the one end 33 and deformed against the repulsive force due to elasticity, and the other limit switch 39 detects that the protruding piece 24 of the driven dog 20 is in contact with the one end 33 as shown in FIG. In addition, a state in which the stopper 30 comes into contact with the other end 34 and deforms the other end 34 against an elastic repulsion force is detected.

The operation of this embodiment will now be explained.

FIG. 1 shows a state in which the rotating shaft 4, the driving dog 14, and the driven dog 20 are all in the neutral position, and when the rotating shaft 4 is rotated clockwise in the figure from the state shown in FIG. The driving dog 14 fixed to the driving dog 14 rotates together, and the driven dog 20 rotates drivenly by the mechanical resistance of the bearings 21 and 22 that constitute the interlocking means 27.

When the rotating shaft 4, the driving dog 14, and the driven dog 20 rotate clockwise by a strong 130 degrees, the protruding piece 24 of the driven dog 20 touches one end 33 of the stopper 30, as shown in FIG. After this, leaving the driven dog 20,
Only the rotation shaft 4 and the driving dog 14 rotate.

At this time, since the rotational torque that the driven dog 20 receives from the bearings 21 and 22 of the interlocking means is not strong, the one end 33 of the stopper 30 is hardly deformed. does not operate one limit switch 38, and the driven dog 20 is not bounced back when it hits the stopper 30 due to the rotational torque received from the bearings 21, 22 of the interlocking means 27.

When the rotation shaft 4 and the driving dog 14 rotate clockwise by 90 degrees from the state shown in FIG. 2 (more than 220 degrees from the state shown in FIG. The driven dog 20 comes into contact with the protruding piece 24, and then the driving dog 1
The rotating shaft 4, the driving dog 14, and the driven dog 20 further rotate while the projecting edge 15 of the driven dog 20 elastically deforms the one end 33 of the stopper 30 via the protruding piece 24 of the driven dog 20.

Then, when the limit switch 38 is rotated several more degrees and in the state shown in FIG. 3, which is 225 degrees from the state shown in FIG. When the overrun is detected, the motor 3 is stopped, and the rotation shaft 4, the driving dog 14, and the driven dog 20 are stopped by the repulsive force of the stopper 30, and the overrun of the rotation shaft 4 is restricted.

Then, from the overrun state shown in FIG. 3, the rotation shaft 4 is reversed and rotated counterclockwise to return the rotation shaft 4 from the overrun state. The driving dog 14 rotates counterclockwise, and the driven dog 20
is pushed back by the repulsive force of the stopper 30 which also serves as a repulsion means and rotates counterclockwise, and also rotates counterclockwise in conjunction with the rotation shaft 4 by the interlocking means 27, so that the rotation shaft 4 Simultaneously with the reversal of , the limit switch 38 returns to its original state, and it is detected that the limit switch 38 is no longer in an overrun state.

Furthermore, if the rotation shaft 4 continues to rotate counterclockwise from this state, the rotation shaft 4, the driving dog 14, and the driven dog 20 will rotate more than 265 degrees counterclockwise from the state shown in FIG. In the moved state, the protruding piece 24 of the driven dog 20 comes into contact with the other end 34 of the stopper 30, and after this, only the rotating shaft 4 and the driving dog 14 rotate, leaving the driven dog 20 behind.

At this time, since the rotational torque that the driven dog 20 receives from the bearings 21 and 22 of the interlocking means is not strong, the other end 34 of the stopper 30 is hardly deformed, so that the protruding piece of the driven dog 20 24 will not operate the other limit switch 39, and the driven dog 20 will not be bounced back when it hits the stopper 30 due to the rotational torque received from the bearings 21, 22 of the interlocking means 27. .

Then, when the rotating shaft 4 and the driving dog 14 rotate counterclockwise by 180 degrees (over 445 degrees from the state shown in FIG. 3) from this state, the other end 17 of the protrusion 15 of the driving dog 14 rotates.
contacts the protruding piece 24 of the driven dog 20, and then the protruding edge 15 of the driving dog 14 passes through the protruding piece 24 of the driven dog 20,
The rotation shaft 4, the driving dog 14, and the driven dog 20 further rotate while elastically deforming the other end portion 34 of the stopper 30.

Then, after rotating several more degrees, in the state shown in FIG. 4, which is 450 degrees from the state shown in FIG. When the overrun is detected, the motor 3 is stopped, and the rotation shaft 4, the driving dog 14, and the driven dog 20 are stopped by the repulsive force of the stopper 30, and the overrun of the rotation shaft 4 is restricted.

Then, from this overrun state shown in FIG. 4, the rotation shaft 4 is reversed and rotated clockwise.
When the motor returns from the overrun state, the driving dog 14 rotates clockwise together with the rotation shaft 4, and the driven dog 20 rotates.
The rotation shaft 4 is pushed back by the repulsive force of the stopper 30, which also serves as a repulsion means, and rotates counterclockwise, and rotates clockwise in conjunction with the rotation shaft 4 by the interlocking means 27.
Simultaneously with the reversal of the limit switch 39, the limit switch 39 returns to detect that the limit switch 39 is no longer in an overrun state.

As described above, in this embodiment, the rotation range of the rotation shaft 4 is 450 degrees, and the limit switches 38 and 39 can detect overruns at both ends of the rotation range, and the stopper 30 can detect overruns. When run regulation is achieved and the overrun state is eliminated, limit switches 38 and 39 immediately detect that the overrun state is no longer present.

In this embodiment, the interlocking means 27 is provided between the rotating shaft 4 and the driven dog 20 to generate mechanical resistance between the rotating shaft 4 and the driven dog 20. Dog 2
0 in a driven manner together with the rotation shaft 4, the interlocking means 27 may be provided between the driving dog 14 and the driven dog 20.

Furthermore, this interlocking means 27 is not necessarily necessary for returning the limit switches 38 and 39, and even without the interlocking means 27, the protrusion 24 of the driven dog 20 can be pushed by the stopper 30, which also serves as a repulsion means. By returning it, the limit switches 38 and 39 can be reset.

Furthermore, in this embodiment, the stopper 30 is made of an elastic body such as urethane rubber.
Although the function of the repulsion means is not limited to this, it is also possible to provide a repulsion means separate from the stopper 30. In this case, the repulsion means may include a spring or other material in addition to an elastic body such as urethane rubber. Biasing means can be used.

Furthermore, in this embodiment, one stopper 30 is used to restrict rotation in both directions, but separate stoppers may be used to restrict rotation in each direction.

[0043]

As described above, according to the present invention, the rotation range of the rotation axis can be made over 360 degrees, and the overrun detection by the sensor and the overrun restriction by the stopper can be performed at both ends of the rotation range. Moreover, when the overrun condition is eliminated, the sensor immediately detects that the overrun condition is no longer present.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of a rotation control device of the present invention in a neutral state.

FIG. 2 is a cross-sectional view of the same embodiment in a state where the rotation shaft is rotated clockwise.

FIG. 3 is a cross-sectional view of the same embodiment in a state where the rotation shaft is overrun in the clockwise direction.

FIG. 4 is a cross-sectional view of the same embodiment in a state where the rotation shaft is overrun in the counterclockwise direction.

FIG. 5 is a longitudinal sectional view of the same embodiment.

FIG. 6 is a side view of a vertically articulated robot using the rotation control device of the same embodiment.

[Explanation of symbols]

1 Rotation control device 4 Rotation axis 8 Base 14 Motive dog 20　　　　Driver Toku 27 Interlocking means

Claims (2)

[Claims] 1. A rotation control device for controlling the rotation of a rotation shaft with respect to a base, the device comprising: a driving dog provided on the rotation shaft and rotating together with the rotation shaft; and a driving dog rotatably provided on the rotation shaft. and a driven dog engaged with the driving dog so as to be rotatable within a predetermined range; a stopper provided on the base for regulating the rotational range of the driven dog; and a stopper provided on the base to restrict the rotational range of the driven dog; The invention is characterized by comprising a repulsion means that applies a repulsion force to push the driven dog back against the stopper, and a sensor that detects that the driven dog has come into contact with the stopper against the repulsion force by the repulsion means. Rotation control device. Claim 2: A claim characterized by comprising interlocking means for generating resistance between at least one of the rotating shaft and the driving dog and the driven dog to passively rotate the driven dog together with the rotating shaft. The rotation control device according to item 1.