JPS6341815Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of small electric motors, particularly small electric motors in which the rotor rotates with vibration, such as an inductor type synchronous motor.

A small electric motor of the present invention is a small electric motor of a type in which a rotor is rotatably supported by a fixed rotor shaft. It is characterized in that a damper is inserted, and the friction damper is formed by parts that frictionally engage with the rotor and the fixed stator, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of a conventional small electric motor and a small electric motor of the present invention will be described below with reference to the drawings.

Figure 1 shows a conventional inductor-type synchronous motor, where 1 is the outer sheath that also serves as the magnetic path of the stator, 1-2 and 1-3 are the end plates thereof, and 1-4 is the stator. An iron core, 2 a stator winding, 3 a rotor shaft fixed to the end plates 1-2, 1-3 of the jacket 1, 4 a rotor rotatably supported by the rotor shaft 3; 5 is a pinion provided on the end surface of the rotor 4, 6 is an output shaft, and 7 is an output shaft gear.

In the motor shown in Fig. 1, the stator core 1-
Magnetic poles are arranged alternately on the inner diameter side of the stator core 1-4, and when an alternating current is passed through the stator winding 2 wound around the outer circumference of the stator core 1-4, the magnetic poles provided on the stator core 1-4 are AC magnetic poles are generated, which attract or repel the permanent magnets provided in the rotor 4, which are disposed opposite to the stator core 1-4 through an air gap, and drive the rotor 4 to rotate. There is.

However, the operation of an inductor-type synchronous motor with such a structure is due to the attraction or repulsion between the alternating current magnetic poles generated in the magnetic poles of the stator and the magnetic poles of the permanent magnets provided in the rotor. In many cases, the position of the magnetic pole of the motor always moves in an oscillatory manner, repeating overshoot and return with respect to the direction of rotation.
Such vibrations can cause problems such as teeth colliding with each other when the reduction gears mesh, producing noise, so in order to reduce the vibrations of the rotor, it is fixed to the end face of the rotor 4. A thrust spring 8 was inserted between the end plate 1-2 of the rotor 4 to apply friction to the end face of the rotor 4 to reduce vibration.
Since this frictional force is configured to apply force to the end surface of the rotor 4 in the thrust direction, a large force cannot be obtained, and there are also problems such as wear of the thrust spring 8 and the end surface of the rotor 4.

The present invention solves the problems of the prior art and provides a rotor vibration damping device that is stable and has a long life. An embodiment thereof is shown in FIG.

In the present invention, a friction damper 10 is provided at a portion opposite to the pinion 5. This damper 10 includes a cylindrical portion 10-1 that fits on the inner circumference of the rotor 4, a sliding portion 10-2 that sandwiches and contacts the rotor shaft 3, and a cylindrical portion that connects the sliding portion 10-2 to the rotor shaft 3. The connecting portion 10-3 is elastically connected to the connecting portion 10-1, and these are integrally molded with resin.

Further, a small projection 10-4 is provided on the outer periphery of the cylindrical portion 10-1, and this engages with the inner peripheral surface of the rotor 4 so that the damper 10 rotates integrally with the rotor 4. The inner diameter of the sliding part 10-2 of the damper 10 is made so that the free dimension before mounting it on the rotor shaft 3 is slightly smaller than the outer diameter of the rotor shaft 3, and when it is mounted on the rotor shaft 3. The sliding part 10-2 is the rotor shaft 3
so that it is pressed against the outer periphery of the

Since the small electric motor of the present invention has the above-described configuration, when the rotor shaft 3 rotates, friction occurs between the sliding part 10-2 and the fixed rotor shaft 3, which causes vibrations of the rotor 4. will be reduced.

In the damper 10 shown in FIG.
The surface roughness of the sliding surfaces of -2 and rotor shaft 3 can be finished extremely finely, so the friction coefficient is stable, and therefore there is little wear and a long life can be expected. It has the advantage of having a wide range of applications because the damping characteristics can be changed by adjusting the friction torque by changing the length in the direction.

Further, in the small electric motor of the present invention, since the damper 10 does not protrude from the side surface of the rotor, there is an advantage that the axial length of the electric motor does not have to be increased.

In the above embodiment, the sliding portion 1 of the damper 10
0-2 may be fixed so as not to rotate in the rotational direction with respect to the fixed rotor shaft 3, and the cylindrical portion 10-1 may be brought into frictional sliding contact with the inner circumferential surface of the rotor 4 instead.

In another embodiment of the damper 10, as shown in FIGS. 3a and 3b, instead of using the sliding part 10-2 and the connecting part 10-3 shown in FIG. 2, a plate-shaped spring part 10- is used.
5 so that the tip of the spring part 10-5 becomes a sliding part, or as shown in FIG. 3c, the cylindrical part 10
The sliding portion 10-2 may be arranged at a position shifted in the axial direction from the sliding portion 10-1.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional inductor type synchronous motor, Fig. 2a is a longitudinal sectional view of the rotor periphery of the small electric motor of the present invention equipped with a damper, and Fig. 2b is A of Fig. 2a. The cross-sectional views taken along line -A' and FIGS. 3a to 3c are illustrations of other embodiments of the damper, respectively. DESCRIPTION OF SYMBOLS 1... Outer cover, 2... Stator winding, 3... Rotor shaft, 4... Rotor, 5... Pinion, 6... Output shaft, 7... Output shaft gear, 8... Thrust spring, 1
0...Pedulum damper.

Claims (1)

[Scope of utility model registration request] In a small electric motor of the type in which a rotor is rotatably supported by a fixed rotor shaft, a cavity is formed between the rotor shaft and the rotor, a friction damper is inserted in this cavity, and the rotor is rotatably supported by a fixed rotor shaft. A small electric motor characterized in that a friction damper is formed by a portion that frictionally engages a rotor and a fixed stator, respectively.