JPH11113237A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepping motor which can be manufactured at a low cost and can be assembled easily. SOLUTION: A rotor of a stepping motor is constituted of a holder 5 which is integrally molded with at least a gear section 5a and formed to have one recessed section 5b and a magnet 6 arranged on the outer periphery of the holder 5. The number of pieces of metal 3 arranged in the housing of the motor is reduced to one by constituting the motor in a rotatable state by arranging one piece of metal 3 in the recessed section 5a. Therefore, the centering problem which arises at the time of assembling the motor can be eliminated.

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 for an information device, a measuring instrument or an air conditioner for a vehicle, and more particularly, to a method for easily performing centering, suppressing characteristic variations, and easily installing the device. It relates to a stepping motor that can be used.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a conventional stepping motor. FIG. 3 is a sectional view of a main part of the stepping motor. In FIG. 3, a metal 23 is fixed to the upper plate 21 and the lower plate 22 by press fitting or the like, and a shaft rotatably supported by the upper and lower metals 23. A ring-shaped magnet 26 is arranged on 24 via a magnet holder 25.

On the other hand, a stator is arranged in the magnet 26 with a predetermined gap therebetween, and the stator is configured in two stages so that the coils 27 and 28 are covered by yokes 29 and 30, respectively. Also, the shaft 24
Has one end protruding outward from a housing formed of the upper and lower plates 21 and 22. A gear 31 made of synthetic resin is press-fitted into this protruding portion to transmit the motor output to the outside.

[0004]

However, in the above-described configuration, since the metal 23 is disposed on each of the upper and lower plates 21 and 22, it is very difficult to center the metal, and the characteristics vary greatly depending on the state of the core. Would. In order to facilitate the centering, it is possible to solve the problem by increasing the clearance between the shaft and the metal, but then, the shaft 24 dances in the metal,
May cause abnormal noise.

[0005] A pinion gear or the like is mounted on the shaft 24. However, if a resin gear is press-fitted, the press-fitting area is small, and at high temperatures, the pull-out strength and rotational strength are insufficient. A metal gear that can be used is used, which is expensive.

Accordingly, an object of the present invention is to provide a stepping motor which solves the above-mentioned problem and is inexpensive and can be easily assembled.

[0007]

According to the present invention, a rotor is
At least a gear part is formed integrally and a holder is formed so as to have a concave part, and a magnet arranged on the outer peripheral part of the holder is constituted. A metal is arranged in the concave part to be rotatable. The above-mentioned problem is solved by the configuration described above, whereby only one metal is required to be disposed on the housing, so that the problem of centering at the time of assembling can be eliminated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A stepping motor according to the present invention
In a stepping motor in which a rotor is arranged in a housing formed of upper and lower plates together with a stator so as to interpose a predetermined gap therebetween, the rotor has at least a gear part integrally formed, and a recess is partially formed. It has a holder formed so as to have the magnet and a magnet arranged on the outer peripheral portion of the holder, and is configured to be rotatable by disposing a metal in the recess. It is preferable that the metal is fixed to a part of the housing, and the holder is fixed to a shaft rotatably supported via the metal. Further, a rotor having a shaft fixed to a part of the housing and metal fixed to the recess may be rotatably supported on the shaft.

[0009]

FIG. 1 is a sectional view of a main part of a stepping motor according to an embodiment of the present invention. In FIG. 1, an upper plate 1 and a lower plate 2 constitute a housing, in which a stator and a rotor are arranged with a predetermined gap therebetween. As for the stator, coils 7 and 8 are respectively connected to yokes 9 and
A two-stage configuration is provided so as to be covered by the reference numeral 10.

On the other hand, the rotor has a magnet holder 5 made of synthetic resin and a magnet 6 arranged on the outer periphery of the magnet holder 5.
The gear part 5a is integrally formed and the recess 5 is partially formed.
b. Here, the metal 3 fixed to a part of the housing is arranged so as to face the recess 5b, and the magnet holder 5 is fixed to the shaft 4 rotatably supported via the metal 3. Let me.

Reference numeral 11 denotes a spring for biasing the rotor, and reference numeral 12 denotes a slide washer for receiving the rotor biased by the spring 11.
Further, in the present embodiment, the metal 3 is directly fixed to the housing. However, the metal 3 may be configured via a metal holder or the like.

With this configuration, only one metal is required for the housing, and there is no problem in the conventional centering. Therefore, the housing can be easily assembled. In addition, since the gear portion is formed integrally with the magnet holder, the contact area with the shaft can be increased, and the gear can be mounted as a resin gear, thereby eliminating the need for a metal gear.

[0013]

Embodiment 2 FIG. 2 is a sectional view of a main part of a stepping motor according to another embodiment of the present invention. That is, in the figure, the shaft is fixed to a part of the housing,
The metal 3 is pressed into the recess 5 b of the magnet holder 5, and the rotor thus configured is rotatably supported on the shaft 4. Since other configurations are the same as those in the above-described embodiment, the same reference numerals are given and their explanation is omitted. Although not particularly shown in this embodiment, a spring, a washer and the like are provided as in the above-described embodiment. It does not matter. Even in this case, the same operation and effect as the above embodiment can be obtained.

It should be noted that the present invention is not limited to the above embodiments, but can be implemented with appropriate modifications without departing from the gist of the present invention. For example, it goes without saying that the magnet holder and the magnet may be integrally formed when the magnet holder is molded with resin.

[0015]

As described above, according to the present invention, the rotor is provided on the outer periphery of the holder, the holder having at least the gear portion integrally formed and having a recess at a part thereof. And a metal arranged in this recess so that the housing is rotatable, so that only one metal is arranged in the housing, and therefore there is no problem of centering when assembling. can do. Therefore, it is not necessary to provide a large clearance between the shaft and the metal, so that it can be easily incorporated and the generation of abnormal noise can be prevented.

Further, since the gear and the holder are integrally formed, the contact area with the shaft can be increased.
In terms of the pull-out strength and the rotational strength, it can be sufficiently secured, and the mounting as a resin gear is enabled, so that a low-cost product can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a stepping motor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a stepping motor according to another embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a conventional stepping motor.

[Explanation of symbols]

 1, 21 ‥‥ upper plate 2, 22 ‥‥ lower plate 3, 23 ‥‥ metal 4, 24 ‥‥ shaft 5, 25 ‥‥ magnet holder 5a ‥‥ gear section 5b ‥‥ recess 6, 26 ‥‥ magnet 7 , 8,27,28 ° coil

Claims (3)

[Claims] 1. A stepping motor in which a rotor is arranged in a housing made of upper and lower plates together with a stator with a predetermined gap therebetween, wherein the rotor has at least a gear part integrally formed,
The holder is formed so as to have a recess in a part thereof, and a magnet is provided on an outer peripheral portion of the holder, and is configured to be rotatable by disposing a metal in the recess. Stepper motor. 2. The stepping motor according to claim 1, wherein the metal is fixed to a part of the housing, and the holder is fixed to a shaft rotatably supported via the metal. 3. A stepping motor according to claim 1, wherein a shaft is fixed to a part of said housing, and a rotor having metal fixed to said recess is rotatably supported on said shaft.