JPS5850820B2 - indexing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an indexing device for an indexing shaft whose rotation angle is positionally controlled.

Conventionally, when accurately detecting the indexing reference position set on the indexing axis, a very high-performance detector with high resolution, which is used for positioning at any angle, was used as is. The indexing shaft cannot be rotated very quickly when detecting the indexing reference position, and therefore it takes a lot of time to detect the indexing reference position.

SUMMARY OF THE INVENTION In order to eliminate such conventional drawbacks, an object of the present invention is to mesh a worm with a worm wheel that rotates integrally or synchronously with an indexing shaft, and to rotate the worm by a drive device connected to a high-performance detector. In an indexing device for rotationally positioning an indexing shaft, the worm is provided so as to be able to slide in the axial direction of the worm and to be freely engaged with and detached from the worm wheel, and to always mesh at a constant position in the axial direction and rotational direction of the worm, Separately from the high-performance detector, an indexing reference position detection means set on the indexing shaft or a member that rotates synchronously with the indexing shaft is used to detect the indexing reference position and the detection means when the worm and the worm wheel are engaged. By providing the detection means at a position where the angular phase difference with the position is an integral multiple of the rotation angle per tooth of the worm wheel, the detection means only needs to detect every rotation angle per tooth, making it very easy to detect the index reference position. It is an object of the present invention to provide an indexing device which is easy to use and can shorten the time required to detect the index reference position because the index reference position can be detected by rotating the index shaft relatively quickly.

Next, the constituent elements of the present invention will be explained with reference to the drawings.

A worm wheel 2 is provided integrally with an indexing shaft 1, and a worm 3 that meshes with the worm wheel 2 is provided so as to be freely engageable and detachable from the worm wheel 2 by sliding in the axial direction of the worm 3.

The worm 3 is rotationally driven by a drive device 4, and a high performance detector 6 detects an accurate rotation angle.

Further, when the worm 3 is slid in the axial direction and is engaged with the worm wheel 2, the worm 3 is always engaged at a constant position in the axial direction and rotational direction.

Therefore, the angular phase difference A between the indexing reference position P set at the center of a specific tooth of the worm wheel 2 integrated with the indexing shaft 1 and the meshing center position Q between the worm 3 and the worm wheel 2 is as follows. If the rotation angle per tooth of the worm wheel 2 is θ, it can generally be expressed as A=N1θ+C.

Here, N is an integer including zero, and C is a constant.

(The figure shows the case where N1=2.C=O.

) On the other hand, the detection means 5 for the index reference position P is provided at a position where the angular phase difference B between the detection position R of the detection means 5 and the meshing center position Q can be expressed as B-N2θ+C.

(The figure shows the case where N2=6.C=O.

) A control device 7 for controlling the drive device 4 is provided.

The control device 7 confirms the indexing of the indexing reference position P based on the detection signal from the detecting means 5, and also performs the above-mentioned operations including the case where the indexing reference position P is accurately stopped at the detection position R. When the indexing shaft 1 is to be accurately stopped at an arbitrary angular position, the driving device 4 is stopped upon receiving an accurate position detection signal from the high performance detector 6.

Next, the operation of the present invention will be explained.

It is assumed that the worm 3 and the worm wheel 2 are disengaged.

The worm wheel 2 is stopped at an arbitrary position in the rotational force direction, and therefore the index reference position P of the worm wheel 2 is also stopped at an arbitrary position in the rotational direction.

Further, the rotation angle of the worm 3 is detected by a high-performance detector 6, and the worm 3 is stopped at a fixed position in the rotation direction.

When it is necessary to detect the indexing reference position of the indexing shaft 1 in such a state, first slide the worm 3 in the axial direction without rotating it, and then align it with the worm wheel 2 at a constant position in the axial direction. Bite together.

During this engagement, the indexing reference position P is rotated by a certain angle, but no matter where the indexing reference position P is in the rotational direction, the worm 3 is engaged at a constant position in the axial direction. , the angular phase difference A between the index reference position P and the engagement center position Q can be expressed as A=N1θ+C.

In other words, no matter where the index reference position P is located in the rotational force direction,
The value of C can be represented by a single constant.

- The force detection means 5 is provided at a position where the angular phase difference B between the detection position R of the detection means 5 and the engagement center position Q can be expressed as B=N2θ+C, so that the index reference position P and the detection position The angular phase difference with R, that is, the angular phase difference between A and B can be expressed as D-(Nt N2)θ.

Therefore, the index reference position P is always located at a position that is an integral multiple of the rotation angle θ per tooth of the worm wheel 2 from the detection position R.

In this state, when the worm 3 is rotationally driven by the drive device 4, the worm wheel 2 is rotated, and the index reference position P is rotated.
is rotated to the detection position R, detected by the detection means 5, and a detection signal is sent to the control device 7.

At this time, it is sufficient for the detection means 5 to be a device that is not very accurate.

In other words, if it is possible to detect at least an angle smaller than half of the rotation angle θ per tooth, it is possible to distinguish between adjacent teeth. This is because it is possible to change it.

Therefore, it is possible to detect the index reference position P by rotating the worm wheel 2 relatively quickly.

Note that in order to accurately stop the indexing reference position P at the detection position R, the control device 7
If indexing positioning at an arbitrary angle is required, the indexing shaft 1 is rotated continuously without stopping at the detection position R, and the high-performance detector 6 is used to stop the drive device 4. Detect and stop at a certain angular position.

If rotational indexing is not required, the worm 3 is slid in the axial direction to disengage the worm wheel 2,
The worm 3 is positioned and stopped at a fixed position in the rotational direction and waits.

In the above explanation, the index reference position P is set at the tooth center of the worm wheel 2, but it is not limited to the tooth center and can be set at any position on the circumference of a member etc. that rotates synchronously with the index shaft 1. Although the indexing reference position P is set at one location, if a plurality of locations are set, it is possible to detect the indexing reference position P in a shorter time than when using only one location.

Furthermore, in the above explanation, the worm 3 is positioned at a certain position in the rotational direction before engaging with the worm wheel 2, but it is of course possible to position the worm 3 after engaging the worm wheel 2. is a state where the meshing center position Q is constant, that is, the general formula for the angular phase difference A is A=N1θ+
The worm 3 may be rotated so that the value of C at C becomes a predetermined constant value, and the index reference position P may be detected after the engagement condition is satisfied. .

As described above, the indexing device of the present invention slides the worm on the worm wheel that rotates integrally or synchronously with the indexing shaft in the direction of the worm's axial force, and can be freely engaged and disengaged from the worm wheel. When the worm and the worm wheel are engaged, the indexing reference position and the detecting position of the detecting means are provided so that they mesh at a certain position in the direction and rotational force direction, and the detection means for the indexing reference position set on the indexing shaft is set on the indexing shaft. Since the worm wheel is installed at a position where the angular phase difference between the two and Moreover, since the indexing reference position can be detected by rotating the indexing shaft relatively quickly, the detection time can be greatly shortened.

[Brief explanation of the drawing]

The figure is a diagram showing the principle of construction of the indexing device of the present invention. DESCRIPTION OF SYMBOLS 1... Indexing shaft, 2... Worm wheel, 3... Worm, 4... Drive device, 5... Detection means, P... Index reference position, R... Detection position.

Claims (1)

[Claims] 1. An indexing device in which a worm is engaged with a worm wheel that rotates integrally or synchronously with an indexing shaft, and the worm is rotationally driven by a drive device connected to a high-performance detector to rotationally position the indexing shaft, The worm is slidable in the axial direction of the worm and can be freely engaged with and detached from the worm wheel, and is always engaged with the worm at a fixed position in the axial direction and rotational direction of the worm. The detection means for the indexing reference position set on the indexing shaft or a member that rotates in synchronization with the indexing shaft is set to the angular position between the indexing reference position and the detection position of the detection means when the worm and the worm wheel are engaged. An indexing device characterized in that the indexing device is provided at a position where the phase difference is approximately an integral multiple of the rotation angle per tooth of the worm wheel.