JPH0737587U - Multi-rotation axis origin detection mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To quickly and accurately set the multi-rotation axis to the initial state. [Structure] A half-disk-shaped slitter having a central angle of 180 ° rotates in synchronization with the multi-rotation shaft 11 at the same number of rotations. The origin position of the multi-rotation shaft 11 is 180 ° from the predetermined position
When rotated over the above, the slitter 24 also becomes 1
It rotates over 80 ° and the photo sensor 2
5 detects such a state, and the multi-rotating shaft 11 moves 180
It is set to the initial state by the rotation of less than °.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention, in an automatic machine, for example, an industrial robot such as a welding robot, sets the initial position by moving the origin position of a multi-rotation shaft that can rotate over 360 ° or more to a predetermined position. In this case, the present invention relates to a multi-rotation axis origin detection mechanism capable of quickly and accurately setting the multi-rotation axis origin position.

[0002]

[Prior art]

 Industrial robots such as welding robots in which a work such as a welding torch is moved according to preset work contents rotate the work over 360 ° by using a multi-rotating shaft that can rotate over 360 ° or more. It has become possible. The multi-rotating shaft is configured to be able to rotate in either forward or reverse directions by transmitting the rotation of a prime mover such as a motor after being decelerated.

In such a robot using a multi-rotation axis, when starting the 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 keep the circumferential position of the multi-rotation shaft set in advance. Therefore, an origin position that can specify the circumferential position is set on the multi-rotation shaft, and the multi-rotation shaft is rotated so that the origin position becomes a predetermined position at the beginning of the work.

A detection mechanism for detecting that the origin position of the multi-rotation shaft has reached a predetermined position is usually a semi-circular disc-shaped member arranged on the input shaft of an encoder that detects the rotation angle of the multi-rotation shaft. Has a slitter. In the slitter, one end of the straight edge corresponds to the circumferential origin of the multi-rotation shaft.

In the rotation area of the slitter, a photo sensor is arranged as a detector for detecting that the edge of the slitter corresponding to the origin position of the multi-rotation axis 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 of all, check if the photo sensor detects a half-disk shaped slitter. For example, if the origin of the multi-rotation shaft is moved from the predetermined position in the + direction by a predetermined angle and the photo sensor detects the slitter, the motor is driven in reverse. Then, when the origin of the multi-rotation shaft reaches a predetermined position and the edge of the edge corresponding to the origin of the multi-rotation shaft 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 shaft is in a state of moving from the predetermined position in the − direction by a predetermined angle and the photo sensor does not detect the slitter, the motor is driven in reverse. To be done. Then, when the origin of the multi-rotation shaft reaches a predetermined position and the end portion of the edge corresponding to the origin of the multi-rotation shaft in the slitter is not detected by the photo sensor, the driving of the motor is stopped. .

In this way, the multi-rotation shaft is set to the initial state in which the origin position is moved to the predetermined position.

[0009]

[Problems to be solved by the device]

 In such a detection mechanism, the input shaft of the encoder to which the slitter is attached converts the rotation range of the multi-rotation shaft, which has become 360 ° or more, into the rotation range of 360 °, with respect to the multi-rotation shaft. It is in a decelerated state. For example, in a multi-rotation shaft that can rotate ± 200 ° to rotate over 400 °, a semi-disc-shaped slitter with a central angle of 180 ° can rotate at half the rotation angle of the multi-rotation shaft. It corresponds to a certain rotation angle of 200 °. Therefore, even when the multi-rotation axis is rotated by + 200 ° from the origin position, the photo sensor is in the state of detecting the slitter, and conversely, even when it is rotated by -200 ° from the origin position, the photo sensor Is not detecting the slitter.

For this reason, first, when the multi-rotation shaft is in a state of rotating over + 180 ° to 200 °, the photosensor detects the slitter, and the multi-rotation shaft is reversed. Become. Therefore, the origin of the multi-rotation shaft is moved to a predetermined position by rotating the multi-rotation shaft over 180 ° or more. 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, when the multi-rotation shaft can rotate to a large rotation angle such as 720 ° or 1440 °, the multi-rotation shaft may have a large rotation angle at the beginning of the origin adjustment. In that case, the origin position must be moved to a predetermined position by reversing by the rotation angle, and there is a possibility that the origin position cannot be accurately adjusted to the predetermined position.

The present invention solves such a problem, and an object thereof is to accurately and promptly move the origin of a multi-rotation shaft to a predetermined position and set the initial state. It is to provide a detection mechanism of a multi-rotation shaft that can perform.

[0013]

[Means for Solving the Problems]

 The multi-rotation shaft detection mechanism of the present invention detects that the origin position of the multi-rotation shaft, which can rotate over 360 ° or more, reaches a predetermined position by decelerating and transmitting the rotation of the prime mover. It is a rotary axis origin detection mechanism, and it has a semi-circular shape that rotates synchronously at the same number of revolutions as the multi-rotation axis, and one end of the linear edge is the origin of the multi-rotation axis. It is characterized by comprising a corresponding detected object and a detection means for detecting that the origin position of the detected object has reached a predetermined position, whereby the above object is achieved. It

[0014]

In the multi-rotation shaft detection mechanism of the present invention, the semi-disc-shaped object to be detected having a central angle of 180 ° rotates at the same number of revolutions in synchronization with the multi-rotation shaft. When the origin position of the shaft has rotated 180 ° or more from the predetermined position, the object to be detected has rotated 180 ° or more, and such a condition is detected by the detector, and the multi-rotation shaft is rotated 180 °. The rotation of less than ° moves the origin position to the specified position.

[0015]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a multi-rotating shaft having an origin detecting mechanism of the present invention, and FIG. 2 is a front view thereof. As shown in FIG. 1, a multi-rotating shaft 11 having a work such as a welding torch (not shown) at its tip is rotatably held at the axial center of a casing 12. A transmission shaft 14 is coaxially connected to the base end of the multi-rotation shaft 11 by a suitable coupling 13, and a reduction gear 15 is fitted to the transmission shaft 14. The reduction gear 15 meshes with an output gear 18 that is attached to the output shaft 17 of the motor 16 in a fitted state. The motor 16 can rotate in the forward and reverse directions.

When the motor 16 is rotationally driven, the rotation of the motor 16 is transmitted to the reduction gear 15 via the output gear 18, and is transmitted to the transmission shaft 14 while being decelerated by the reduction gear 15. Then, the multi-rotating shaft 11 that is coaxial with the transmission shaft 14 rotates integrally with the transmission shaft 14 in the decelerated state at the same number of rotations.

As described above, the rotation of the motor 16 that rotates at high speed is decelerated and transmitted to the multi-rotation shaft 11 over ± 200 ° so that it can rotate over 360 ° or more, 400 ° in this embodiment. It is rotatable.

The transmission shaft 14 extends to the outside of the casing 11, and the origin detection mechanism 20 is attached to the tip of the transmission shaft 14. As shown in FIGS. 1 and 2, the origin detection mechanism 20 has a first transmission gear 21 mounted on the tip of the transmission shaft 14 in a fitted state. The first transmission gear 21 is designed to rotate integrally with the transmission shaft 14, and therefore rotates in synchronization with the multi-rotation shaft 11 connected to the transmission shaft 14 at the same rotational speed. The first transmission gear 21 is meshed with the second transmission gear 22, which is attached to the rotary shaft 23 in a fitted state.

The two transmission gears 21 and 22 have the same number of teeth, and therefore the respective transmission gears 21 and 22 rotate synchronously at the same number of rotations. Therefore, the second transmission gear 22 also rotates in synchronization with the multi-rotation shaft 11 at the same rotation speed. The rotary shaft 23, to which the second transmission gear 22 is attached and rotates integrally with the second transmission gear 22, also rotates in synchronization with the multi-rotation shaft 11 at the same rotation speed.

A semi-disk-shaped slitter 24 having a central angle of 180 ° is fitted in a fitted state to the tip of the rotary shaft 23 to which the second transmission gear 22 is attached. The slitter 24 is designed to rotate integrally with the rotary shaft 23, and thus is synchronously rotated at the same rotational speed as the multi-rotary shaft 11. One end 24b (see FIG. 4A) of the linear edge 24a of the slitter 24 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 attached to the transmission shaft 14 to which the first transmission gear 21 is attached. The rotation is input to the encoder 28 (see FIG. 2). The encoder 28 is input with the reduction gear 27 decelerated so that the rotation range of the multi-rotation shaft 11 that rotates over 400 ° becomes the rotation 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 across the rotation range of the slitter 24 is arranged. The photo sensor 25 is arranged corresponding to a predetermined position moved when the origin position of the multi-rotation shaft 11 is set to the initial state. The photo sensor 25 is a detector that detects the semi-disk-shaped slitter 24 as a detection target. The photo sensor 25 is in an off state while the slitter 24 is located between the light emitting element and the light receiving element, and the slitter 24 is It is in the ON state while it is not located between the light emitting element and the light receiving element.

In the multi-rotating shaft 11 having such a configuration, when the operation of the robot is started, first, the multi-rotating 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 based on the flowchart shown in FIG. When the origin alignment is instructed, the control device confirms whether the photosensor 25 is in the on state or the off state (step S1 in FIG. 3, the same applies hereinafter). When the photo sensor 25 is in the on state, the motor 16 is driven in the normal direction (step S2), while when the photo sensor 25 is in the off state, the motor 16 is driven in the reverse direction (step S2). 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. The rotation of the multi-rotation shaft 11 by the normal rotation of the multi-rotation shaft 11 causes the multi-rotation shaft 11 to rotate in a direction indicated by an arrow A, and the slitter 24 which rotates integrally with the multi-rotation shaft 11 also rotates in the same direction. Then, the end 24b corresponding to the origin position of the linear edge 24a of the slitter 24 is detected by the photo sensor 25, and the photo sensor 25 is turned off (step S4 in FIG. 3), FIG. 4 (a). As indicated by the chain double-dashed line, the multi-rotation shaft 11 is in a predetermined origin state.

Similarly, when the photo sensor 25 is off, the slitter 24 is positioned between the light emitting element and the light receiving element of the photo sensor 25, as shown in FIG. The rotation of the multi-rotating shaft 11 due to the reverse rotation of 16 rotates in the direction indicated by the arrow B, and the slitter 24 rotating integrally with the multi-rotating shaft 11 also rotates in the same direction. Then, when the end portion 24b corresponding to the origin of the linear 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), FIG. As indicated by the chain double-dashed line, the multi-rotation shaft 11 is in a predetermined origin state.

In this way, when the origin of the multi-rotation shaft 11 is moved to a predetermined position and set in the initial state, the multi-rotation shaft 11 is operated according to preset control contents. .

As described above, since the semi-disk-shaped slitter 24 integrally rotates with the multi-rotation shaft 11 at the same rotational speed, the origin position of the multi-rotation shaft 11 is It always coincides with the predetermined position of the slitter 24. Therefore, when setting the multi-rotation shaft 11 in the initial state, it is sufficient to rotate the multi-rotation shaft 11 over 180 ° or less.

[0029]

[Effect of device]

 As described above, the multi-rotation axis detection mechanism of the present invention has a semi-circular detection object having a central angle of 180 ° and rotates at the same number of revolutions in synchronization with the multi-rotation axis. When the origin position of the shaft rotates 180 ° or more from the predetermined position, the object to be detected also rotates 180 ° or more, and such a condition is detected by the detector, and the multi-rotating shaft rotates 180 °. It is set to the initial state by rotating it less than °. Therefore, the multi-rotation shaft can be quickly and accurately set to the initial state.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a multi-rotating shaft having an origin detecting mechanism of the present invention.

FIG. 2 is a front view thereof.

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

FIG. 4A and FIG. 4B are explanatory views for explaining the operation of the origin detection mechanism.

[Explanation of symbols]

 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 rotating shaft 24 slitter 25 photo sensor

Claims (1)

[Scope of utility model registration request] 1. A multi-rotation axis origin detection mechanism for detecting that the origin position of a multi-rotation axis capable of rotating over 360 ° or more has reached a predetermined position by decelerating and transmitting the rotation of a prime mover. It has a semi-circular shape that rotates synchronously at the same number of revolutions as the multi-rotation axis, and one end of the linear edge corresponds to the origin of the multi-rotation axis. A multi-rotation axis origin detection mechanism comprising: a detection unit that detects that the origin position of the detected object has reached a predetermined position.