JPH0442762A - Detector for revolution of motor - Google Patents

Abstract

PURPOSE:To reduce the overall length of a motor so as to compact it by arranging a detector in a peripheral case, and detecting a plurality of slot grooves of a rotor so as to detect the revolution of a motor. CONSTITUTION:A rotation detector 4 is arranged, in the posture that it faces the periphery of a rotor 3, at the specified position (upper part in the figure) in circumferential direction of a motor case 1. A reflector 3c is provided at the periphery of each rotor yoke 3c of the rotor 3. When the rotor 3 is rotated, the slot groove 3b of the rotor 3 and the other part (reflector 3c) passes by the front of the detector 4 alternately. If a photoreflector, wherein a light emitting element and a light receiving element are united, is used as the detector 4, difference occurs in the output of the photoreflector 4, between the slot groove 3b of the rotor 3 and the other part (reflector 3c), and based on this output change, the revolution of the rotor 3 can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a detection device suitable for detecting the rotation of a small DC motor of an eye reflex camera, a video camera, or the like.

[Conventional technology]

Conventional motor rotation detection devices of this type include, for example, an optical motor rotation detection device composed of a rotating slit plate directly connected to the motor rotation shaft and a light emitting/receiving element, or a rotating magnet and coil directly connected to the motor rotation shaft. A magnetic motor rotation detection device consisting of

[Technical problem to be solved by the invention 1! ! However, in the conventional motor rotation detection device described above, since a rotating slit plate or a rotating magnet is attached directly to the rotating shaft, there are the following technical problems.

) Since the detection device is attached directly to the motor rotating shaft, the overall length of the motor becomes longer.

11) The rotation detection device has a large number of parts, has a complicated structure, and is expensive.

The present invention has been made in view of these technical problems, and it is possible to reduce the overall length of the motor and make it more compact.Moreover, the number of parts is small, simplifying the structure and reducing costs. It is an object of the present invention to provide a rotation detection device for a motor that is capable of detecting rotation of a motor.

[Means for solving problems]

The present invention provides a rotation detection device for a motor having an iron-core rotating rotor and a permanent magnet fixed to an outer case portion thereof, in which at least one detection element is arranged in the outer case portion, and a plurality of slots of the rotor are provided. By adopting a configuration that detects the rotation of the motor by detecting the groove, the overall length of the motor can be reduced and made more compact.Moreover, the number of parts is small, simplifying the structure and reducing costs. The present invention provides a motor rotation detection device.

In this case, the rotation detection elements include a pair of light emitting/receiving elements,
Alternatively, a capacitance sensing element can be used.

〔Example〕

FIG. 1 is a schematic cross-sectional view taken along the line II in FIG. 2 showing an embodiment of the motor rotation detection device according to the present invention, and FIG. FIG.

In FIGS. 1 and 2, an iron-core rotating rotor 3 is rotatably supported at the center of the inside of a motor case 1 via a rotating shaft 6. As shown in FIG.

The rotor 3 is fixed to the center of the rotating shaft 2 via a collar 7, and inside the rotor 3, three winding coils 8 are installed at three equal positions in the circumferential direction. .

The iron-core rotating rotor 3 is composed of rotor yokes 3a divided into three equal parts in the circumferential direction corresponding to the number of the wire-wound coils 8, and a slot groove of a predetermined width is provided between each rotor yoke 3a. 3b is provided.

Two magnets (permanent magnets) 2 serving as stators are fixed to the inner circumferential surface of the motor case 1, and face the outer circumferential surface of the rotor 3 with a gap between them.

The illustrated motor is a DC motor, which is generally suitable as a small motor.

Therefore, a rotation detection element 4 is disposed at a predetermined position in the circumferential direction of the motor case 1 (in the illustrated example, at the top) in a posture facing the outer circumferential surface of the rotor 3.

The rotation detection element 4 detects changes in the state of the circumferential surface of the rotor 3 when it rotates, and is composed of, for example, a photoreflector in which a light emitting element and a light receiving element are integrated.

On the other hand, a reflecting portion 3C is provided on the outer circumferential surface of each rotor yoke 3a of the rotor 2, and when the circumferential surface of the rotor 3 is viewed from the position of the photoreflector 4, there are three reflecting portions 3C and The three slot grooves 3b are arranged so as to appear alternately.

The rotation detection element (photoreflector) 4 is fixed to the outer periphery (upper part) of the motor case 1 with screws 11, and is electrically connected to a substrate (circuit board) 5.

In the above configuration, when the winding coil 8 is energized to rotate the rotor 3, the slot groove 3b and the other portion (the reflective portion 3c) of the rotor 3 alternately pass in front of the detection element 4. I will do it.

Therefore, if a photoreflector in which a light emitting element and a light receiving element are integrated is used as the detection element 4,
The slot groove 3b of the rotor 3 and the other parts (for example, the reflection part 3c) are connected to the photoreflector.
4, and the rotation of the rotor 3 can be detected based on this output change.

According to the embodiment described above, the rotation detection element 4 is fixed using the outer circumference of the motor case 1, and the passage of the rotor 3 through the plurality of slot grooves 3b is optically detected. Compared to the conventional structure in which the device is directly connected to the rotating shaft (corresponding to the rotating shaft 6 of this embodiment), the length of the motor can be shortened and the structure can be made more compact.

In addition, since the rotating slit plate or rotating magnet that is directly connected to the rotating shaft 6 in the conventional structure can be omitted, the number of parts can be reduced and the structure can be simplified.
It was also possible to reduce costs.

FIG. 3 is a cross-sectional view similar to FIG. 1 showing another embodiment of the motor rotation detection device according to the present invention.

In the present embodiment, in the above-mentioned embodiment, the position opposite to the detection element 4 (position with a phase difference of 180 degrees), that is,
In the illustrated example, a second rotation detection element 9 and a substrate 10 for mounting the second rotation detection element are added to the lower part of the motor case 1.

This embodiment has a substantially superior configuration to that of the embodiments shown in FIGS. 1 and 2, except for the addition of the above-mentioned detection section.
Corresponding parts are indicated by the same reference numerals, and detailed explanation thereof will be omitted.

The detection element mounting board (circuit board) 10 is fixed to the motor case 1 with screws or the like, and the second detection element 9 is fixed to the detection element mounting board 10 in an electrically connected state.

This second detection element 10 is also composed of, for example, a photoreflector, like the detection element 4, and is
It is attached so that it faces the outer circumferential surface of the

According to this embodiment, since the second rotation detecting element 9 is added in the arrangement shown in FIG. When detecting, in two rotation detection parts facing each other,
We were able to obtain outputs with different phase differences.

In each of the above embodiments, the rotor rotation detection element 4
．． Although 9 shows an example in which a photoreflector that integrates a light emitting element and a light receiving element is used, similar rotation detection is also possible by using an element that can detect changes in capacitance instead. be.

[Effects of the Invention] As is clear from the above description, according to the present invention, in a rotation detection device for a motor having a cored rotating rotor and a permanent magnet fixed to the outer circumferential case portion, at least one detection Since the rotation of the motor is detected by arranging the element in the outer peripheral case and detecting the plurality of slot grooves of the rotor, the overall length of the motor can be reduced and the motor can be made more compact.
Provided is a motor rotation detection device that has a small number of parts, has a simple structure, and can reduce costs.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view (line I-I in FIG. 2) showing an embodiment of the motor rotation detection device according to the present invention, and FIG. FIG. 3 is a schematic cross-sectional view showing another embodiment of the motor rotation detection device according to the present invention. Below, symbols representing main components in the drawings are listed. 1 Motor case, 2--Magnet (permanent magnet), 3- Rotor, 3a--Rotor yoke, 3b Slot groove, 3c--Reflector, 4
---1 detection element (photoreflector), 5 detection elements are mounted on the board, 6--rotation shaft, 8--1 winding coil, 9--2nd detection element (photo reflector) reflector
), 10 - - The second detection element is mounted on the board. Figure 1 Figure 2

Claims (3)

[Claims] (1) In a rotation detection device for a motor having an iron-core rotating rotor and a permanent magnet fixed to its outer case, at least one detection element is arranged in the outer case, and a plurality of slot grooves of the rotor are provided. A motor rotation detection device characterized in that the rotation of the motor is detected by detecting the rotation of the motor. (2) The motor rotation detection device according to claim 1, wherein the detection element is a pair of light emitting/receiving elements. (3) The motor rotation detection device according to claim 1, wherein the detection element is a capacitance detection element.