JPS62181645A - Stepping motor - Google Patents

Abstract

PURPOSE:To miniaturize a position detector and to detect the position of a rotor honestly at low cost by arranging an optical reflector coaxially with a rotor gear and providing a detecting section having a photoluminescent subsection and a photoreceptive subsection opposite to the reflector. CONSTITUTION:A rotor 8 is formed by fixing to a shaft 5 rotor gears 1 and 4, an optical reflector 2 with nearly the same diameter as in the diameters 1 and 4 and a rotor magnet 3 in the axially laminated condition coaxially. On the other hand, a detecting section 7 having a photoluminescent subsection and photoreceptive subsection is provided to a circuit substrate 6 in the position opposite to the tooth-tip of a rotor gear 1. The beam injects from the photoluminescent subsection of the detecting section 7 to the optical reflecting section composed of the rotor gear 1 and the optical reflector 2. The beam reflects to the amount in proportion to the area of the opposite optical reflector 2 and injects to the photoreceptive subsection of the detecting section 7. The amount of this incident beam is converted into the electric signal, by which the position of the rotor 8 is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a stepping motor that can detect the position of its rotor and operate in an optimal drive mode.

BACKGROUND OF THE INVENTION In the recent highly information-oriented society, there is a demand for faster equipment. In order to achieve higher speeds, stepping motors use open-loop speed control, but due to variations in motor performance and load fluctuations, it has been difficult to increase speeds by fully utilizing motor performance. For this reason, stepping motors, which are equipped with a position detector and a speed detector and control the speed while checking the tracking state of the motor to fully utilize the motor's performance, are attracting attention.

An example of a conventional position detector used in the above-mentioned stepping motor will be described below with reference to the drawings.

FIG. 4 shows the appearance of a conventional stepping motor equipped with a position detector. In FIG. 4, 21 is a slit disk attached to the motor shaft 22, and 23 is a light receiving/emitting element having a light emitting section 24 and a light receiving section 25 facing each other with the slit disk 21 in between.

The operation of the position detector configured as above will be explained below.

First, the slit disk 21 attached to the shaft 22
The light output from the light emitting section 24 hits the light receiving section 25 which faces the slit hole of the slit disk 21 . At this time, the output of the light receiving section 25 changes depending on the amount of light entering the light receiving section 25. Therefore, slit disk 21 per rotation
The output is l for the number of slit holes! I get caught.

However, in the above configuration, since the position detector is attached separately from the motor body, there is a problem that the position detector is attached separately from the main body of the motor. It is difficult to maintain a constant correspondence between the plate's sleeves (and holes), and the position of the rotor tooth tip relative to the stator tooth tip cannot be accurately detected by JT.Furthermore, there is a problem that the number of parts increases, resulting in high costs. was.

In view of the above-mentioned problems, the present invention provides a position detector for a stepping motor that is built into the motor body, is small in size, is low in cost, and is capable of faithfully detecting the position of the rotor.

``Means for Solving the Problems'' To solve the two-legged problem, the position detector for a stepping motor of the present invention comprises a rotor having a light reflecting plate arranged coaxially with the rotor gear and fixed to the shaft, and the rotor gear described above. A light-emitting section and a light-receiving section are arranged opposite to the tips of the teeth and the light reflecting plate, and a growth detecting section is constructed.

Effect of the Invention With the above-described configuration, the present invention can accurately detect the position of the rotor by using the tips of the teeth of the rotor gear, and can also be made smaller (and lower in cost).

Example Below, regarding a stepping motor according to an example of the present invention,
This will be explained with reference to the drawings.

FIG. 1 shows the configuration of a rotor of a stepping motor in a first embodiment of the present invention.

In FIG. 1, 1 and 4 are rotor gears, 2 is a light reflecting plate with approximately the same diameter as the outer diameter of the rotor gear 1.4, and 3 is a rotor magnet!・These are coaxially stacked in the axial direction and fixed to the shaft 5 in a soft manner.

FIG. 2 shows the positional relationship between the rotor and the photodetector in the above embodiment. In FIG. 2, reference numeral 6 denotes a circuit board, and a detecting section 7 having a light emitting section and a light receiving section is provided at a position facing the tooth tips of the rotor gear 1.

FIG. 3 shows the overall configuration of the above embodiment, where 8 is a rotor having the configuration shown in FIG. 1, and 9 is a stator core 10.
A stator is provided with an excitation winding 11, and 12.13 is a cover that supports the shaft 5 and covers the stator 9.

The operation of the stepping motor position detector configured as described above will be described below with reference to FIGS. 1 and 2.

In FIG. 1, light enters the light reflecting section composed of the rotor gear 1 and the light reflecting plate 2 from the light emitting section of the detecting section 70 in FIG. is reflected and enters the light receiving section of the detection section 7. The amount of this incident light is converted into an electrical signal, and the position 1-8 can be detected.Here, the light reflecting plate 2 is made of a material with a high light reflectance, such as a steel plate or a plastic plate, plated and painted. The rotor gear 1 has a zigzag side with a small light reflectance on the side facing the detection section 7.

As described above, according to this embodiment, by combining the rotor gear 1 and the light reflection plate 2, it is possible to obtain the excellent effects of miniaturizing the position detector, lowering the cost, and being able to faithfully detect the rotor position. .

Effects of the Invention As described above, the present invention includes a rotor having a light reflecting plate arranged coaxially with the rotor gear and fixed to the shaft, and a detecting unit having a light emitting part and a light receiving part facing the reflecting plate. , the rotor position can be accurately detected at low cost while reducing the size.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of the rotor of a stepping motor according to an embodiment of the present invention, Fig. 2 is a perspective view showing the positional relationship between the rotor and a photodetector, and Fig. 3 is a stepping motor equipped with a foot position detector. FIG. 4 is an exploded perspective view of the motor. FIG. 4 is a perspective view of a conventional stepping motor equipped with a position detector. 1...Rotor gear, 2...Light reflecting plate,
5...Shaft, 7...Detection section, 8.
...Rotor, 9...Stator. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 j I 3

Claims (1)

[Claims] A stator having a stator core wound with a wire, a rotor gear facing the stator through a gap, a rotor having a light reflecting plate coaxially arranged with the rotor gear and having approximately the same diameter as the rotor gear, and fixed to a shaft; A stepping motor comprising a detection section having a light emitting section and a light receiving section facing the tips of teeth and a light reflecting plate.