JPH06327219A - Stepping motor - Google Patents

Abstract

PURPOSE:To offer thin stepping motors provided with a transmission mechanism that enable the thinning of sets. CONSTITUTION:A PM stepping motor is provided with two sets of stators 4a, 4b, transmission mechanism 8 on a rotor 7 located in the gap L between the stators, and opening in the motor frame 5 to transmit output. This constitution offers thin stepping motors that enable thin sets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor used in a lens driving device used in a video camera or the like, a floppy disk head driving device, various OA and AV equipment driving devices and the like.

[0002]

2. Description of the Related Art In recent years, as devices have become lighter, thinner, shorter, and smaller, their driving stepping motors have also become smaller, and it is required to improve the volumetric efficiency of the motor and to effectively use the set volume of the motor output transmission mechanism. There is.

A conventional PM type stepping motor will be described below with reference to the drawings. Figure 3 shows a conventional PM
Type stepping motor, in which a ring-shaped coil 2 is wound around a first bobbin 1 and the outer circumference thereof is paired with a pair of yokes 3a, 3a.
The first stator portion 4a, which is covered by b and has comb-teeth-shaped pole teeth arranged on the inner peripheral surface of the yoke, and the second stator portion 4b which is similar to the first stator portion 4a. And a rotor 10 provided with two sets of cylindrical permanent magnets 6 having a plurality of magnetized outer circumferences inside the two sets of stators. The output shaft of the rotor 10 is provided with a gear 11.

In the above structure, the comb-teeth pole teeth of the yoke are excited by successively energizing the coils of the respective stators, and the rotor is attracted or repelled by a plurality of magnetized opposing rotors, so that the rotor is rotated. It rotates and transmits the output by the gear 11 of the rotor output shaft.

[0005]

In such a conventional stepping motor, the height of the output gear has been a problem due to the structure of the motor when the set is made thinner.

Further, there is a problem of insufficient fixing strength between the output shaft and the gear when the device is made thin. The present invention solves the above problems, and an object of the present invention is to provide a stepping motor that enables a set to be thin.

[0007]

In order to achieve the above object, the present invention provides an empty part between a first stator part and a second stator part, and incorporates a transmission mechanism such as a gear into this empty part. It is configured.

[0008]

With the above-described structure, the present invention allows a transmission mechanism such as a gear to be incorporated in the motor body, and enables the set to be thin.

[0009]

(Embodiment 1) A stepping motor according to a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan cross-sectional view of a PM type stepping motor of the present invention, in which an imaginary part L is provided in a first stator part 4a and a second stator part 4b and a rotor 7 located in the imaginary part L is provided. Gear 8 is provided, and stator portions 4a, 4b
The motor frame 5 for holding is provided with an opening for transmitting output.

As described above, according to the PM type stepping motor of this embodiment, it is possible to reduce the thickness of the motor having a gear as a transmission mechanism.

(Second Embodiment) FIG. 2 is a plan sectional view of a PM type stepping motor according to a second embodiment of the present invention, in which a cylindrical permanent magnet 6 and a shaft 12 are fixed in a rotor 7 of the first embodiment. The gear 13 is integrally formed with the resin.

[0013]

As is apparent from the above embodiments, according to the present invention, it is possible to provide a stepping motor capable of reducing the thickness of a set.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a stepping motor according to a first embodiment of the present invention.

FIG. 2 is a plan sectional view of a stepping motor according to a second embodiment of the present invention.

FIG. 3 is a plan sectional view of a conventional stepping motor.

[Explanation of symbols]

 1 bobbin 2 coils 3a, 3b yokes 4a, 4b stator part 5,9 motor frame 6 permanent magnets 7,10 rotors 8,11,13 gears 12 shafts

Claims (1)

[Claims] 1. A ring-shaped coil is wound around a first bobbin, and the outer circumference of the bobbin is covered with a pair of yokes.
On the inner peripheral surface of the yoke, a stator composed of a first stator part in which comb-shaped pole teeth are arranged, and a second stator part similar to the first stator part, and a plurality of stators on the outer periphery are provided. A PM-type stepping motor formed by a rotor having a cylindrical permanent magnet that is magnetized as described above, and an empty part is provided between the first stator part and the second stator part A stepping motor, which is provided with a transmission mechanism and has an opening in the stator portion to perform output transmission.