JPH0694481A - Rotating quantity detecting device - Google Patents

Abstract

PURPOSE:To facilitate the optical mutual positioning of a light source, a subject and a light receiving element. CONSTITUTION:A rotating quantity detecting device emits a light from a light emitting element 2 to irradiate a subject 12 on a shaft 5 and detects the reflected light by 8 light receiving element 3. The device is provided with a detecting part 4 having the light emitting element 2 and the light receiving element 3; positioning members 6, 7, 9, 10, 11 for positioning the detecting part 4 to the shaft 5; and a fixing device 8 for fixing the detecting part 4 positioned to the shaft 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation amount detecting device for detecting the rotation amount of an object.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open No. 1-297513 discloses
`` In a method of irradiating a subject with light from a light source and measuring reflected or transmitted light by the subject with an optical sensor to measure a physical quantity relating to the subject, a light transmitting part and a light blocking part, or a light reflecting part Section and the light absorbing section have a pitch ξ, and a structure having a periodic structure in which the width δ of the light transmitting section or the light reflecting section is sufficiently smaller than ξ, a linear structure that emits coherent light is used. Irradiation with a divergent light beam from a light source, the direction of the length d of the linear light source is made parallel to the periodic direction of the periodic structure, and the relationship between ξ and d is 1/10 ≦
By setting d / ξ ≦ 2, a shadowing pattern by diffraction corresponding to the periodic structure is obtained, and the amount of movement of the shadowing pattern due to the movement of the structure in the direction crossing the irradiation light flux is determined by A moving amount measuring method characterized by detecting the moving amount of the structure by detecting with a sensor "is described, and an optical rotary encoder using this moving amount measuring method is described.

In Japanese Patent Laid-Open No. 63-47616, "A light from a light source is applied to a subject, and a reflected light or a transmitted light from the subject is detected by an optical sensor to determine a physical quantity relating to the subject. In the measuring method, a monoperiodic structure as an object is irradiated with a divergent light flux from a monochromatic point light source, and the positional relationship between the point light source, the structure, and the optical sensor is adjusted to obtain a single structure of the structure. An enlarged shadowy diffraction pattern corresponding to a periodic structure is generated at the position of the optical sensor, and the movement amount of the shadowy diffraction pattern accompanying the movement of the structure in a direction crossing the illumination luminous flux is detected by the optical sensor. Detecting the movement amount of the structure to measure the movement amount, '' is described, and,
An optical rotary encoder using this moving amount measuring method is described.

Further, Japanese Patent Laid-Open No. 2-57913 discloses that "a cylindrical body that is coaxially integrated with a subject is irradiated with light from a light source, and light reflected by the cylindrical body is detected by an optical sensor. The method of measuring the amount of rotation of a magnetic recording layer, wherein a magnetic pattern written in a magnetic recording layer with a magnetic head is developed with a magnetic colloid fluid to form a lattice pattern on the peripheral surface of the cylindrical body, and the reflected light is used to form the lattice pattern. A rotation amount measuring method characterized by detecting the movement of the shadow pattern caused by diffraction based on the lattice pattern by the optical sensor "
And an optical rotary encoder using this moving amount measuring method.

[0005]

In the above-mentioned optical rotary encoder, the optical mutual alignment of the light source, the subject, and the optical sensor is delicate, and its adjustment is complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotation amount detecting device which improves the above-mentioned drawbacks and facilitates optical mutual alignment of a light source, a subject and a light receiving element.

[0007]

To achieve the above object, the invention according to claim 1 irradiates a subject on a shaft with light from a light emitting element and detects the reflected light with a light receiving element. In the device, there are provided a detection part having the light emitting element and the light receiving element, an axial alignment member for axially aligning the detection part and the shaft, and the detection part axially aligned with the shaft. The invention according to claim 2 is provided with a fixing device for fixing.
The rotation amount detection device according to claim 1, further comprising a positioning member for performing absolute positioning in the rotation direction of the shaft when the shaft is mounted on the shaft.

[0008]

According to the first aspect of the present invention, the detecting portion having the light emitting element and the light receiving element and the shaft are axially aligned with each other by using the member for axial alignment, and the detecting portion which is axially aligned with the shaft is provided. It is fixed by the fixing device.

According to a second aspect of the invention, in the rotation amount detecting device according to the first aspect, the positioning member performs absolute positioning in the rotational direction of the shaft when it is mounted on the shaft.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the outline of one embodiment of the present invention. The movement amount detection device 1 of this embodiment constitutes a shaft type optical rotary encoder, and a detection portion 4 formed by integrally forming a light emitting element 2 and a light receiving element 3 which are light sources.
A shaft 5 composed of a rotary shaft, rotary shaft direction fixing members 6 and 7 having a shape and a function which are attached to the rotary shaft 5 so as to be movable in that direction (longitudinal direction), and the movement amount detection device 1 And a mounting device 8 for fixing the device to the outside. The detection part 4, the rotational axis direction fixing members 6, 7 and the mounting device 8 are connected by three connecting members 9, 10, 11.

A subject 12 for detecting the amount of rotation is provided on the rotating shaft 5 and is coaxially and integrally connected to an object 13 for detecting the amount of rotation. The movement amount detecting device 1 is inserted in the direction of arrow 14 so that the hole formed at the center of the rotary shaft direction fixing members 6 and 7 fits into the rotary shaft 5, and is mounted as shown in FIG. The mounting device 8 is the rotation amount detection target 13
Is fixed to the external substrate 14 which supports the shaft. in this case,
The subject 12 is not in contact with the detection portion 4 and the detection portion 4
And the position in the direction of the rotary shaft 5 match. Then, as shown in FIG. 3, the light 15 emitted from the light emitting element 2 is applied to the subject 12, and the reflected light 16 thereof strikes the light receiving element 3.

When detecting the rotation amount of the subject 12,
Coherent light 15 is emitted from the light emitting element 2 to the subject 12 on the rotating shaft 5. As shown in FIG. 4, the subject 12 has a periodic diffraction grating structure provided periodically along the rotation direction of the rotary shaft 5. When the coherent light 15 from the light emitting element 2 is incident on the subject 12 having this periodic diffraction grating structure, the light 15 is reflected by the subject 12 and the position of the light receiving element 3 is caused by the diffraction and interference effect of the light. In FIG. 5, as shown in FIG. 5, a peculiar silhouette-like bright and dark pattern 18 represented by the contrast of light is projected on the virtual circular screen 17, and the peculiar silhouette-like bright and dark pattern 18 is detected by the light receiving element 3.

In order to generate a unique shadow-like bright and dark pattern 18 at the position of the light receiving element 3, the light emitting element 2 and the light receiving element 3
And a specific optical mutual arrangement relationship of the subject 12 is required, but in this example, the light emitting element 2 and the light receiving element 3 are 1
The light-emitting element 2, the light-receiving element 3, and the subject 12 are unitized as one detection portion 4 and the positioning of the detection portion 4 with respect to the subject 12 in the rotation axis direction is standardized by mounting by the mounting device 8. The arrangement of is adjusted.

Further, in order to generate a shadow-like bright and dark pattern 18 peculiar to the position of the light receiving element 3 as the reflected light 16 with respect to the subject 12 having the periodic diffraction grating structure, the size of the light emitting element 2 is another condition. That is, the subject 12
The size (length) of the light emitting element 2 in the direction parallel to the grating arrangement direction in the periodic diffraction grating structure
When the pitch width of the periodic diffraction grating structure of is ξ, the following relationship may be satisfied between d and ξ.

(1/10) .ltoreq. (D / .xi.). Ltoreq.2 Therefore, the movement of the characteristic shadowy bright-dark pattern 18 accompanying the rotation of the subject 12 having the periodic diffraction grating structure is detected by the light receiving element 3. The rotation amount of the subject 12, that is, the rotation amount of the rotation shaft 5 is measured to measure the rotation amount of the rotation amount detection target 13.

FIG. 7 shows a specific structure of this embodiment.
A laser diode is used as the light emitting element 2, and a photodiode is used as the light receiving element 3. Ball bearings are used as the rotation axis direction fixing members 6 and 7, and screws are used as the mounting device 8. The ball bearings 6 and 7 are the connecting members 9 and 10 and the screw 1.
It is coupled to the coupling member 11 by 9, 20 and the detection part 4 is coupled to the coupling member 11. An object 12 having a periodic diffraction grating structure is a magnetic pattern written on a magnetic recording layer on the rotating shaft 5 by a magnetic head and developed with a magnetic colloid fluid, and a coupling member 11 is an external substrate by a screw 8. It is fixed at 14.

Therefore, the coherent light 15 emitted from the laser diode 2 is incident on the subject 12 having a periodic diffraction grating structure and reflected, and due to the diffraction and interference effects of the light, a distinctive shadowing of the light is produced. The pattern 18 is detected by the photodiode 3. The movement of the shadowy bright / dark pattern 18 of light peculiar to the rotation of the rotation shaft 5 is detected by the photodiode 3 as the rotation amount of the rotation shaft 5. Further, the rotation amount detection signal of the photodiode 3 is sent to the control device 22 inside the external substrate 14 via the wiring 21. The rotation amount detection target 13 is rotationally driven by the drive device 23, and the control device 22 receives the rotation amount detection signal from the photodiode 3 to drive the drive device 23.
Is controlled to control the rotation of the rotation amount detection target 13.

In this embodiment, the light emitting element 2 and the light receiving element 3
Are unitized as one detection part 4, and the detection part 4 and the ball bearings 6 and 7 are coupled members 9 and 1.
0, 11 and screws 19, 20 are used to standardize the positioning of the detection portion 4 with respect to the subject 12 in the rotational axis direction by mounting with the mounting device 8. Therefore, the light emitting element 2, the light receiving element 3, and the subject 12 are optically coupled. Mutual alignment is facilitated. Further, it is also possible to detect the rotation amount corresponding to a plurality of rotation amount detection objects, and it is possible to reduce the size and cost of the device.

FIG. 8 shows a part of another embodiment of the present invention.
In this embodiment, the gauge 24 and the pointers 25 and 26 indicating the rotation angle are provided in the above embodiment. The gauge 24 is provided on the subject 12 side of the ball bearing 6, movably fitted on the outer periphery of the rotary shaft 5 and integrally fixed to the ball bearing 6. The gauge 24 is integrally provided with a pointer 25 for indicating the horizontal direction when the movement amount detecting device 1 is attached to the rotary shaft 5. In addition, a pointer 26 for knowing the current rotation angle of the rotary shaft 5 from the gauge 24 as compared with the pointer 25 is integrally added to the rotary shaft 5 at a position closer to the ball bearing 6 than the subject 12. Therefore, when the movement amount detecting device 1 is attached to the rotary shaft 5, the gauge 24 shows how much the rotary shaft 5 is at an angle from the horizontal direction, and the absolute rotation is detected in the future detection of the rotation amount. The corner is revealed.

[0020]

As described above, according to the first aspect of the invention, in the rotation amount detecting device in which light is emitted from the light emitting element to the object on the shaft and the reflected light is detected by the light receiving element, A detection part having an element and the light receiving element, an axial alignment member for axially aligning the detection part and the shaft, and a fixing device for fixing the detection part axially aligned with the shaft. Since it is provided with, the optical alignment of the light emitting element, the light receiving element, and the subject is easily performed, and the apparatus can be downsized and the cost can be reduced.

According to a second aspect of the present invention, in the rotation amount detecting device according to the first aspect, a positioning member for performing absolute positioning in the rotational direction of the shaft when mounted on the shaft is provided. Since it is equipped, the absolute rotation angle can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic exploded perspective view showing an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing the embodiment.

FIG. 3 is a perspective view showing a part of the embodiment.

FIG. 4 is a view showing a part of a subject of the same embodiment.

FIG. 5 is a diagram for explaining the operation of the embodiment.

FIG. 6 is a diagram for explaining the operation of the embodiment.

FIG. 7 is a sectional view specifically showing the same embodiment.

FIG. 8 is a perspective view showing a part of another embodiment of the present invention.

[Explanation of symbols]

 2 Light emitting element 3 Light receiving element 4 Detection part 5 Rotating shaft 6,7 Rotating shaft direction fixing member 8 Mounting device 9, 10, 11 Coupling member 12 Subject

Claims (2)

[Claims] 1. A rotation amount detecting device for irradiating a subject on a shaft with light from a light emitting element and detecting the reflected light by a light receiving element, a detection portion having the light emitting element and the light receiving element, and this detection portion. A rotation amount detecting device, comprising: an axial alignment member for performing axial alignment between the shaft and the shaft; and a fixing device for fixing the detection portion axially aligned with the shaft. 2. The rotation amount detection device according to claim 1,
A rotation amount detecting device comprising a positioning member for performing absolute positioning in the rotation direction of the shaft when mounted on the shaft.