JP2574476Y2 - Multi-rotation axis origin detection mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to an automatic machine, for example, an industrial robot such as a welding robot, which moves the origin position of a multi-rotation shaft capable of rotating over 360 ° to a predetermined position. The present invention relates to a multi-rotation axis origin detection mechanism that can quickly and accurately set the origin position of the multi-rotation axis when setting to an initial state.

[0002]

2. Description of the Related Art An industrial robot such as a welding robot in which a work such as a welding torch is moved in accordance with a preset work content uses a multi-rotation shaft capable of rotating over 360 ° to make the work 360 ° or more. It is possible to rotate over. The multi-rotation shaft is transmitted by reducing the rotation of a prime mover such as a motor,
It can rotate in both forward and reverse directions.

In such a robot using a multi-rotation axis, when starting a work, the work is moved to a predetermined origin position, and a preset work operation is performed from the origin position. For this reason, it is necessary to set the circumferential position of the multi-rotation shaft in a preset state. For this purpose, an origin position at which the circumferential position can be specified is set on the multi-rotation axis, and the multi-rotation axis is rotated at the beginning of the work so that the origin position is at a predetermined position.

A detection mechanism for detecting that the origin position of the multi-rotation shaft has reached a predetermined position is usually a semi-disc-like shape disposed on the input shaft of an encoder for detecting the rotation angle of the multi-rotation shaft. Has a slitter. In the slitter, one end of the straightened edge corresponds to the circumferential origin position of the multi-rotation shaft.

[0005] In the rotation range of the slitter, a photosensor is disposed as a detector for detecting that the edge of the slitter corresponding to the origin position of the multi-rotation shaft has been moved to a predetermined position.

Using such a detection mechanism, the origin position of the multi-rotation shaft is moved to a predetermined position as follows. First, check whether the photo sensor detects a semi-circular slitter. For example, if the origin of the multi-rotation axis has moved from a predetermined position by a predetermined angle in the + direction and the photo sensor has detected a slitter, the motor is driven to rotate in the reverse direction. When the origin of the multi-rotation axis reaches a predetermined position and the end of the edge corresponding to the origin of the multi-rotation axis in the slitter is not detected by the photo sensor, the driving of the motor is stopped.

On the other hand, if the origin of the multi-rotation axis is shifted from the predetermined position by a predetermined angle in the negative direction and the photo sensor does not detect the slitter, the motor is driven to rotate in the reverse direction. You. Then, when the origin of the multi-rotation axis becomes a predetermined position and the end of the edge corresponding to the origin of the multi-rotation axis in the slitter is not detected by the photo sensor, the driving of the motor is stopped.

In this way, the multi-rotation axis is set to the initial state where the origin position has been moved to the predetermined position.

[0009]

In such a detection mechanism, the rotation range of the multi-rotation shaft in which the input shaft of the encoder to which the slitter is mounted becomes 360 ° or more is set to 36.
It is in a state of being decelerated with respect to the multi-rotation axis so as to convert to a rotation range of 0 °. For example, in a multi-rotation shaft capable of rotating by ± 200 ° so as to rotate over 400 °, a semi-disk-shaped slitter having a center angle of 180 ° becomes a rotation angle of 200 ° which is a half rotation angle of the multi-rotation shaft. Corresponding to the rotation angle. Therefore, the multi-rotation axis moves +
Even when rotated to 200 °, the photo sensor detects a slitter, and conversely, when rotated to -200 ° from the origin, the photo sensor does not detect a slitter. ing.

[0010] For this purpose, first, the multi-rotation shaft is increased by +18.
When the photo sensor is rotated from 0 ° to 200 °, the photo sensor detects the slitter, and the multi-rotation axis is reversed. For this purpose, the multi-rotation shaft is reversed by 180 ° or more,
The origin of the multi-rotation axis is moved to a predetermined position. As a result, there is a problem that it takes time to move the origin of the multi-rotation axis to a predetermined position.

Further, the multi-rotation shaft is, for example, 720 °, 1
If it is possible to rotate to a large rotation angle such as 440 °, if the rotation angle of the multi-rotation shaft is large at the beginning of the origin alignment, it is reversed by that rotation angle to set the origin position at a predetermined position. , And the origin position may not be able to be accurately adjusted to a predetermined position.

The present invention is to solve such a problem, and an object of the present invention is to accurately and quickly move the origin of a multi-rotation shaft to a predetermined position and set it to an initial state. It is an object of the present invention to provide a detection mechanism for a multi-rotation shaft that can be used.

[0013]

According to the multi-rotation shaft detection mechanism of the present invention, the rotation of the prime mover is transmitted at a reduced speed so that the origin position of the multi-rotation shaft capable of rotating over 360 ° can be set at a predetermined initial position. This is a multi-rotation axis origin detection mechanism that detects that a position has been reached. It has a semi-disc shape that rotates synchronously at the same number of revolutions as the multi-rotation axis, and has one end of a linear edge. Object corresponding to the origin position of the multi-rotation axis, detection means for detecting that the origin position of the detection object has reached a predetermined initial position, and rotation of the multi-rotation axis is reduced.
The rotation angle of the multi-rotation shaft
And an encoder for detecting within a range of 360 °.
Then, the origin position of the object to be detected is determined by the detection means.
When the initial position is detected, the encoder
Is set to the initial state.
Sign .

[0014]

[Function] In the multi-rotation axis detection mechanism of the present invention, the multi-rotation axis
The rotation is transmitted to the encoder in a decelerated state,
The encoder has a multi-rotation axis rotation angle of 360 °
Detected within. Then, since the detection object having a semi-circular shape having a center angle of 180 ° rotates at the same rotation speed in synchronization with the multi-rotation axis, the origin position of the multi-rotation axis is 180 ° or more from a predetermined initial position. When the object rotates over 180 °, such a state is detected by the detector, and the multi-rotation shaft is rotated by 180 °.
By rotation of less than or equal to °, the origin position is moved to a predetermined initial position. In this way, the origin position of the multi-rotation axis
When the initial position is reached, the encoder is reset to the initial state.
The rotation angle from the initial position of the multi-rotation axis.
Is detected by the encoder.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the configuration of a multi-rotation shaft having an origin detecting mechanism according to the present invention, and FIG. 2 is a front view thereof.
As shown in FIG. 1, a multi-rotation shaft 11 on which a work such as a welding torch (not shown) is held at a distal end portion is rotatably held on an axis portion of a casing 12. This multi-rotation shaft 11
A transmission shaft 14 is coaxially connected to a base end of the transmission shaft 13 by an appropriate coupling 13, and a reduction gear 15 is fitted to the transmission shaft 14. The reduction gear 15 meshes with an output gear 18 attached to the output shaft 17 of the motor 16 in a fitted state. The motor 16 can rotate forward and backward.

When the motor 16 is driven to rotate, the rotation of the motor 16 is transmitted to the reduction gear 15 via the output gear 18, and transmitted to the transmission shaft 14 while being reduced by the reduction gear 15. Then, the multi-rotation shaft 11 coaxial with the transmission shaft 14 is integrally and synchronously rotated at the same rotation speed as the transmission shaft 14 in the deceleration state.

As described above, the rotation of the motor 16 rotating at high speed is transmitted to the multi-rotation shaft 11 at a reduced speed.
It is rotatable over ± 200 ° so that it can rotate over 0 °, and in this embodiment, over 400 °.

The transmission shaft 14 extends to the outside of the casing 11, and an origin detecting mechanism 20 is attached to a tip end thereof. As shown in FIGS. 1 and 2, the origin detecting mechanism 20 has a first transmission gear 21 attached to a distal end portion of the transmission shaft 14 in a fitted state. The first transmission gear 21 is configured to rotate integrally with the transmission shaft 14, and therefore, rotates synchronously with the multi-rotation shaft 11 connected to the transmission shaft 14 at the same rotation speed. The first transmission gear 21 meshes with a second transmission gear 22 attached to the rotating shaft 23 in a fitted state.

The two transmission gears 21 and 22 have the same number of teeth, so that the transmission gears 21 and 22 rotate synchronously at the same rotational speed. Therefore, the second transmission gear 2
2 also rotates synchronously at the same rotation speed as the multi-rotation shaft 11. The rotation shaft 23 to which the second transmission gear 22 is attached and rotates integrally with the second transmission gear 22 is also provided.
It rotates synchronously at the same rotation speed as the multi-rotation shaft 11.

A semi-disc-shaped slitter 24 having a center angle of 180 ° is fitted to the tip of a rotating shaft 23 to which the second transmission gear 22 is attached in a fitted state.
The slitter 24 is configured to rotate integrally with the rotating shaft 23, and therefore, is synchronously rotated at the same rotational speed as the multi-rotating shaft 11. One end 24b of the linear edge 24a of the slitter 24 (refer to FIG. 4A) corresponds to the origin position of the multi-rotation shaft 11.

A reduction gear 27 having a larger number of teeth than the first transmission gear 21 is mounted on the transmission shaft 14 to which the first transmission gear 21 is attached. Rotation is encoder 28 (see Fig. 2)
Has been entered. The encoder 28 inputs the rotation range of the multi-rotation shaft 11 rotating over 400 ° while being reduced by the reduction gear 27 so that the rotation range of the multi-rotation shaft 11 becomes 360 °. ,
It is to be detected in a range of 360 °.

In the rotation range of the slitter 24, a photo sensor 25 having a pair of light emitting element and light receiving element arranged with the rotation range of the slitter 24 interposed therebetween is arranged. The photo sensor 25 is arranged corresponding to a predetermined initial position moved when the origin position of the multi-rotation shaft 11 is set to an initial state. The photo sensor 25 is a detector that detects the semi-disc-shaped slitter 24 as an object to be detected. The photo sensor 25 is turned off while the slitter 24 is located between the light emitting element and the light receiving element, and the slitter 24 emits light. As long as it is not located between the element and the light receiving element, it is turned on.

In the multi-rotation shaft 11 having such a configuration, when the operation of the robot is started, first, the multi-rotation shaft 11 is set to an initial state by a control device using a microcomputer or the like. The control for setting the initial state will be described with reference to the flowchart shown in FIG.
When the origin is instructed, the control device checks whether the photo sensor 25 is in an on state or an off state (Step S1 in FIG. 3, the same applies hereinafter). When the photo sensor 25 is on, the motor 16 is driven forward (step S2), and when the photo sensor 25 is off, the motor 16 is driven reverse (step S3). ).

When the photo sensor 25 is on, the slitter 24 is not positioned between the light emitting element and the light receiving element of the photo sensor 25 as shown in FIG. Multi-rotation shaft 1 driven by forward rotation
Due to the rotation of 1, the rotation in the direction indicated by the arrow A, and the slitter 24 rotating integrally with the multi-rotation shaft 11 also rotates in the same direction. Then, the end 24b corresponding to the origin position of the linearized edge 24a of the slitter 24 is detected by the photo sensor 25, and when the photo sensor 25 is turned off (step S4 in FIG. 3), FIG.
As shown by the two-dot chain line, the origin position of the multi-rotation shaft 11 is Tokoro
It becomes the fixed initial position.

Similarly, when the photo sensor 25 is off, the slitter 24 is located between the light emitting element and the light receiving element of the photo sensor 25 as shown in FIG. The rotation of the multi-rotation shaft 11 by the reverse rotation drive 16 rotates in the direction indicated by the arrow B, and the slitter 24 that rotates integrally with the multi-rotation shaft 11 also rotates in the same direction. Then, the end 24b corresponding to the origin of the linearized edge 24a of the slitter 24 is no longer detected by the photo sensor 25 and the photo sensor 25 is turned off (step S5 in FIG. 3), and FIG. At the origin of the multi-rotation shaft 11 as shown by the two-dot chain line
The position becomes a predetermined initial position.

In this way, when the origin position of the multi-rotation shaft 11 is moved to a predetermined initial position , the encoder 2
8 is set to the initial state. Then, the multi-rotation shaft 11
Indicates that the rotation angle detected by the encoder 28 is
The rotation angle is controlled so as to be a preset rotation angle .

As described above, since the semi-disk-shaped slitter 24 rotates integrally with the multi-rotation shaft 11 at the same rotation speed, the origin position of the multi-rotation shaft 11 becomes It always coincides with the predetermined position of the slitter 24.
Therefore, when the origin position of the multi-rotation shaft 11 is set to the initial position, it is only necessary to rotate the multi-rotation shaft 11 over 180 ° or less. Moreover, the rotation angle of the multi-rotation shaft 11
Encoder 28 to detect multiple rotations in 360 ° range
Because it detects the rotation angle of the shaft, it
Set the origin position of the turning shaft 11 to the initial position by rotation of 180 ° or less.
And set the encoder 28 to the initial state
Also, there is no possibility that an error occurs in the encoder 28,
The rotation angle of the multi-rotation shaft is detected with high accuracy.

[0029]

As described above, in the detection mechanism for the multi-rotation shaft of the present invention, the detection object having a semi-circular shape having a center angle of 180 ° rotates at the same rotation speed in synchronization with the multi-rotation shaft. Therefore, the origin position of the multi-rotation axis is 180 ° from the predetermined initial position.
When rotated over the above, the object to be detected is also 180 °
The rotation is performed over the above, and such a state is detected by the detector, and the origin position of the multi-rotation axis is set to the initial position by rotation of 180 ° or less. Moreover,
The encoder is a multi-rotation axis rotation angle within 360 °
, The multi-rotation shaft 11 is
Set to the initial position with a rotation of 80 ° or less, and
Is set to the initial state,
There is no risk of errors and the rotation angle of the multi-rotation shaft can be increased.
It can be detected with accuracy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a multi-rotation shaft having an origin detection mechanism according to the present invention.

FIG. 2 is a front view thereof.

FIG. 3 is a flowchart for explaining the operation of the origin detecting mechanism.

FIGS. 4A and 4B are explanatory views for explaining the operation of an origin detecting mechanism.

[Explanation of symbols]

 Reference Signs List 11 multi-rotation shaft 14 transmission shaft 15 reduction gear 16 motor 17 output shaft 18 output gear 21 first transmission gear 22 second transmission gear 23 rotation shaft 24 slitter 25 photo sensor

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B25J 9/10 B25J 19/02

Claims (1)

(57) [Scope of request for utility model registration] An origin detection of a multi-rotation shaft for detecting that an origin position of a multi-rotation shaft capable of rotating over 360 ° becomes a predetermined initial position by transmitting the rotation of the prime mover at a reduced speed. A mechanism that has a semi-disc shape that rotates synchronously at the same number of rotations as the multi-rotation axis, and one end of a linear edge corresponds to the origin position of the multi-rotation axis. Body, detecting means for detecting that the origin position of the detected body has reached a predetermined initial position, and by transmitting the rotation of the multi-rotation shaft at a reduced speed,
An engine that detects the rotation angle of a multi-rotation shaft within a range of 360 °
And an origin position of the object to be detected is determined by the detecting means in a predetermined initial period.
When the position is detected, the encoder is turned on.
A multi-rotation axis origin detection mechanism characterized by being set to an initial state .