JPH0445012B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] This invention relates to an incremental rotary encoder that detects a rotation angle, and in particular to an incremental rotary encoder that allows easy adjustment of the origin position during installation. Regarding encoders.

"Prior Art" Generally, rotary encoders are widely used as rotation angle detectors that detect rotation angles, but rotary encoders can be broadly classified into:
Classified into incremental type and absolute type.

Here, a conventional optical incremental rotary encoder is constructed as shown in FIG. In this figure, 1 is a rotary plate attached to the end of the input shaft 2, and this rotary plate 1
has a plurality of slits 1a, 1a, along the outer periphery.
. . . are formed at equal intervals, and an origin slit 1b is formed on the inner peripheral side of the row of slits 1a, 1a, . Further, 3 is a light projecting section consisting of light emitting elements (for example, light emitting diodes) 3a, 3b, 3c, and 4 is a detecting section consisting of light receiving elements (for example, photodiodes) 4a, 4b, 4c. and the detection unit 4 are arranged to face each other with the rotary plate 1 in between.
A rotary encoder 5 is configured. The light emitted from the light emitting elements 3a and 3b passes through the slit 1a and is detected by the light receiving elements 4a and 4b, respectively, and the light emitted from the light emitting element 3c passes through the origin slit 1b and is detected by the light receiving element. 4c, each of these light receiving elements 4a, 4b,
4c outputs an A-phase pulse, a B-phase pulse, and a Z-phase pulse as shown in FIG. 4 as the rotating plate 1 rotates. In this case, the light receiving elements 4a and 4b have slits 1a, 1a,
. . . are arranged at intervals of 1/4 pitch, and as a result, the A-phase pulse and
The rotational direction of the rotary plate 1 is detected based on the phase advance/lag of the phase pulses. Also, the rotary plate 1 is 1
The origin position is detected by the Z-phase pulse that is generated once every rotation, and by counting up or down the number of A-phase pulses or B-phase pulses based on this Z-phase pulse, the input shaft is 2 rotation angles are detected.

"Problems to be Solved by the Invention" By the way, in the conventional rotary encoder 5 described above, since only one pulse of the origin signal, that is, the Z-phase pulse, is obtained every time the input shaft 2 rotates once, the detected angle If is less than or equal to π radians, then
There was a problem in that the adjustment of the origin position during installation was complicated. For example, as shown in FIG. 5, the input shaft 2 of the rotary encoder 5 is directly attached to the rotary arm 7 whose rotational range is limited to θ radians less than π radians by limit switches 6a and 6b. When trying to detect the rotation angle of the rotating arm 7, when installing the rotary encoder 5, the origin position is adjusted so that the Z-phase pulse is output within θ radians, which is the rotational range of the rotating arm 7. There must be. As described above, when the detected angle is less than π radian, it is necessary to constantly align the origin when attaching the rotary encoder 5, and this adjustment work is complicated.

This invention was made in view of the above-mentioned circumstances, and provides a rotary encoder that can easily adjust the origin position even when detecting the rotation angle of a rotating object within a range of π radians or less. is intended to provide.

``Means for Solving the Problems'' This invention detects marks provided at a plurality of locations equally divided around the circumference of a rotary plate fixed to an input shaft, and counts the number of detected marks. , an incremental rotary encoder that detects the rotation angle of the input shaft, and in which the detection angle θ is set to π radians or less, an origin mark indicating 2π/θ origins on the rotary plate;
It is characterized by being provided at equal intervals around the circumference.

"Operation" With the above configuration, the number of origin marks of the rotary encoder corresponding to the detection angle θ is: 2 when θ=π, 3 when 2/3π, 6 when 1/3π, 2/9π For 1/6π, there are 9 pieces. For 1/9π, there are 18 pieces. For 1/18π, there are 36 pieces. Therefore, whenever the input shaft rotates within the detection angle θ, The origin mark is detected, making it easy to adjust the origin position during installation.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 are diagrams showing the configuration of an embodiment of the present invention. FIG. 1 shows a case where the detection angle θ is set to π radian, and FIG. 2 shows a case where the detection angle θ is set to π radian.
The case where is set to 1/3π radian is shown in each case. In addition, in these figures, illustration of the slits 1a, 1a, . . . shown in FIG. 3 is omitted.

First, when the detection angle θ is set to π radians, as shown in _FIG .
b ₂ are provided at equal intervals around the circumference. That is, two origin slits 1b ₁ and 1b ₂ are provided on the rotary plate 1 and spaced apart from each other by a central angle α=π radian with the input shaft 2 as the axis.

A rotary encoder incorporating the rotary plate 1 configured in this manner is used to detect the angle of an object whose rotational operation range is set to π radians. As a result, when the input shaft 2 is directly attached to the target object and the rotation angle of the target object is to be detected, the Z-phase pulse (see Fig. 4) is always generated within the range of θ radian, which is the rotational movement range of the target object. 1
Since pulses are output, the origin position alignment can be easily adjusted.

In addition, when the detection angle θ is set to 1/3π radian, as shown in Fig. 2, there are six origin slits 1 on the rotating plate 1 of the rotary encoder.
b ₁ , 1b ₂ , ..., 1b ₆ are provided at equal intervals around the circumference. In other words, the rotary plate 1 has six origin slits 1b ₁ , 1b ₂ , ..., 1b ₆ that are connected to the input shaft 2.
They are spaced apart by a central angle α=1/3π radian with the axis at .

The rotary encoder incorporating the rotary plate 1 configured in this way has a rotational operation range of 1/3π.
Used when detecting the angle of an object set in radians. As a result, when the input shaft 2 is directly attached to the target object and the rotation angle of the target object is to be detected, one Z-phase pulse is always output within the range of θ radian, which is the rotational movement range of the target object. , the origin position alignment can be easily adjusted.

In this way, when the detection angle θ is set to π radians or less, two or more
Origin slit 1b ₁ , 1 indicating 2π/θ or less origins
By providing b ₂ , ... at equal intervals around the circumference,
It becomes easy to adjust the origin position during installation.

In the above-mentioned embodiment, the case where the present invention is applied to an optical incremental rotary encoder is explained as an example, but the present invention can of course also be applied to a magnetic type. In this case, the rotating plate 1 is replaced with a magnetic disk, and marks corresponding to the slits 1a, 1a, . . . and the origin slits 1b ₁ , 1b ₂ , . can be read with a magnetic reading head.

"Effects of the Invention" As explained above, according to the present invention, in an incremental rotary encoder in which the detection angle θ is set to be less than or equal to π radians, 2π/θ pieces of Origin marks indicating the origin are placed at equal intervals around the circumference, so
The effect is that the origin position alignment can be easily adjusted during installation.

[Brief explanation of drawings]

1 and 2 are front views showing the configuration of an embodiment of the present invention; FIGS. 3 and 4 are perspective views and output waveform diagrams for explaining a conventional optical incremental rotary encoder; Fifth
The figure is a front view showing the configuration when the rotary encoder is attached to a rotating arm that is a measurement target. DESCRIPTION OF SYMBOLS 1...Rotary plate, 2...Input shaft, 1a...Slit (mark), _1b1 , _1b2 ,~ _1b6 ...Origin slit (origin mark).

Claims (1)

[Scope of Claims] 1. The rotation angle of the input shaft can be determined by detecting marks provided at a plurality of positions equally distributed around the circumference of a rotary plate fixed to the input shaft and counting the number of detected marks. In an incremental type rotary encoder that detects 2π/θ origins and whose detection angle θ is set to π radians or less, origin marks indicating 2π/θ origins are placed on the rotary plate at equal intervals around the circumference. An incremental rotary encoder characterized by the following: