JPH0528923Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a stepping motor used in printers and typewriters, which utilizes the ability to rotate by one advance angle in response to one input signal.

BACKGROUND ART The structure of a conventional stepping motor will be described below with reference to the drawings. As shown in FIGS. 2 to 4, a conventional stepping motor includes a stator yoke 2 having a plurality of magnetic pole teeth 2a protruding in the axial direction at equal intervals on its cylindrical circumferential surface, and the magnetic pole teeth 2a. and the same number of magnetic pole teeth 3a with the same pitch of pole teeth.
The stator yoke 2 and the frame yoke 3 have the above-mentioned magnetic pole teeth 2a, 3a staggered at equal intervals, and the stator yokes are arranged back to back in the circumferential direction. It is located 1/4 pitch off from the
These magnetic pole teeth 2 a and 3 a form a cylindrical portion inside the stator 4 . In the cylindrical space surrounded by the stator yoke 2, frame yoke 3, and magnetic pole teeth 2a, 3a, an annular stator coil 5, which is wound around coil bobbins 7, 8, is used to switch the excitation of the stator. It is equipped with 6.

A rotor 1 is inserted into the cylindrical portion of the stator 4 at a slight interval, and has a ring-shaped permanent magnet 1a on its outer periphery that is magnetized with multiple poles. As shown in Fig. 2, this rotor is attached to the frame yoke 3 by spot welding 13, etc.
It is rotatably supported inside the stator by bearings 9 and 10 which are fixed via bearing holding plates 11 and 12.

Problems to be Solved by the Invention However, in the above configuration, since the frame yoke 3 and the bearing retaining plates 11 and 12 are joined by spot welding, etc., foreign matter generated during welding may cause malfunction of the rotor or bearing retaining plates 11, 12. When the bearings 9 and 10 are joined to the bearing 12 by press-fitting or caulking, there are problems in that the bearings are twisted or the structure of the bearing becomes complicated.

In view of the above-mentioned problems, the present invention has been developed to provide a stepping motor that solves defects caused by foreign objects generated during welding between a frame yoke and a bearing holding plate, as well as assembly defects when joining a bearing holding plate and a bearing. It provides:

Means for Solving the Problems In order to solve the above problems, the stepping motor of the present invention has a bearing holding part formed integrally with the frame yoke by means of resin outsert molding, and the bearing is fixed. It has a configuration.

Function The present invention can eliminate joining processes such as welding the frame yoke and the bearing holding plate, press-fitting the bearing holding plate and the bearing, and caulking due to the above-described configuration.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the configuration of a stepping motor according to the present invention. The configurations of the rotor section, stator coil, and stator yoke in the figure are the same as those of the conventional example, so the same numbers are given and the explanation thereof will be omitted. 14
15 is a bearing holding plate made of resin, and 16 is a metal mounting plate used when attaching this stepping motor to a mating device.

The manufacturing of this stepping motor begins with the bearing 1.
0, the mounting plate 16, and the left frame yoke 3 are placed in a resin molding mold and resin molded, and the resin bearing holding plate 14 is attached to the bearing 10, the mounting plate 16,
An assembly product in which frame yokes 3 are firmly connected is made. In this assembly, the bearing 10 is inserted into the resin, but the mounting plate 16 and the frame yoke 3 are out-inserted. Reference numeral 14' denotes a small hole drilled in the frame yoke 3, and the injected resin fills the small hole 14' to form a hitch to firmly connect the bearing holding plate 14 and the frame yoke 3. Although not shown, the mounting plate 1
6 is similarly formed with a resin hook to firmly connect it to the bearing holding plate 14.

The same goes for the right half of the motor, and the bearing 9 and the right frame yoke 3 are firmly connected by a resin bearing holding plate 15 to form an assembly.

Stator coils 5 and 6 are attached to each of the above assemblies.
After mounting, the stator yoke 2 is fitted to the frame yoke 3, the rotor 1 is inserted, the two assemblies are brought together, and fixed by welding or gluing, etc., and the first
The stepping motor shown in the figure includes the welding process between the frame yoke 3 and the bearing retaining plates 14 and 15, and the press-fitting of the bearings 9 and 10 into the bearing retaining plates 14 and 15.
It eliminates the joining process such as caulking.

Effects of the invention As described above, the present invention forms a bearing holding part integrally with the frame yoke using a resin molded outsert and fixes the bearing. It is possible to prevent twisting between the bearings that occurs when press-fitting or joining them, and it also simplifies the structure of the bearings.
Further, by using an inexpensive resin material instead of the non-magnetic metal plate, costs can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a stepping motor according to the present invention, Fig. 2 is a sectional view of a conventional stepping motor, Fig. 3 is a perspective view of a stator yoke of a common stepping motor, and Fig. 4 is a conventional stepping motor. FIG. 3 is a perspective view of a frame yoke of a typical stepping motor. 2... Stator yoke, 3... Frame yoke, 9, 10... Bearing, 14, 15... Bearing holding plate.

Claims (1)

[Scope of utility model registration request] A rotor having a ring-shaped permanent magnet with multi-pole magnetization on its outer periphery, and a stator having a plurality of magnetic pole teeth located at equal intervals while maintaining a predetermined air gap on a concentric circle with the outer periphery of the rotor. A frame yoke having a yoke, a frame yoke having magnetic pole teeth of the same pitch shifted at an arbitrary angle as the stator yoke, and an annular stator coil arranged concentrically around the outer circumferential area of the magnetic pole teeth of the stator yoke, molded with resin. A stepping motor comprising a bearing holding part formed integrally with the frame yoke by an outsert, and a bearing fixed to the bearing holding part.