JPS6341816Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synchronous motor, and more particularly to a synchronous motor that prevents axial vibration of a rotor and reduces vibration noise.

Conventionally, it was the first compact and lightweight synchronous motor.
What is proposed is shown in the figure. This synchronous motor 1 has a case 2 consisting of a container-shaped main body 3 and a lid body 4.
A coil structure 5 is housed inside the coil structure 5, and a plurality of stators 6 formed by cutting and forming the main body 3 and the lid 4, respectively, are disposed at the inner peripheral position of the coil structure 5.
Further, the rotor assembly 7 is provided with a rotor 10 which is magnetized with different polarities alternately in the circumferential direction around a boss 9 fitted on the rotation output shaft 8, and a pair of bearings 11, 12, it is rotatably supported. In the figure, 13 is a gear integrally attached to the rotary output shaft 8.

Incidentally, in this type of synchronous motor, the axial position of the rotor 10 is determined by the pair of bearings 1 described above.
For example, in the example shown in FIG. 1, the regulation is performed by contact between the lower surface of the bearing 12 and the upper surface of the boss 9, and by contact between the bearing 11 and the lower end of the rotary output shaft 8. However, it is actually extremely difficult to manufacture and control the dimensions between these with high precision at all times, and therefore it is impossible to avoid slight axial play between the bearings 11, 12 and the rotor assembly 7. do not have.

Therefore, as the rotor 10 rotates, the rotor assembly is vibrated in the axial direction by the amount of play, and this vibration noise appears as motor noise. Also,
The vibrations of the rotor assembly are transmitted to the bearings 11 and 12, the coil structure 5, and the case 2, which adversely affects the durability and reliability of the entire motor. For this reason, conventionally, as shown in the figure, a leaf spring 15 is cantilever-supported on a part 14 of a mechanism for assembling the electric motor 1.
An attempt has been made to prevent shaft vibration of the rotor assembly 7 by biasing the rotary output shaft 8 in one direction (downward) via a presser plate 16 fixed to the tip thereof. However, with this measure, a new leaf spring 15 etc. must be provided each time the mechanism is changed.
This poses a problem of being troublesome and hindering miniaturization of the mechanism, and furthermore, increasing the number of parts and increasing costs.

The present invention has been developed in view of the above, and includes forming a hole in the bottom of the coil frame through which the stator is inserted, and integrally forming a tongue-shaped support piece that protrudes toward the center. By configuring a bearing that supports the lower end of the rotational output shaft of the rotor assembly by providing a concave portion, the axial play of the rotor assembly can be absorbed by elastic deformation of the support piece without using other vibration prevention parts. The purpose of this invention is to prevent the occurrence of vibration, thereby reducing the number of parts and assembly man-hours, and to provide a small, inexpensive synchronous motor.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

2 and 3 show one embodiment,
This synchronous motor 20 has a main body 22 in the shape of a short cylindrical container.
and a lid 23 that fits into the opening of the main body 22. The stator 24 is formed by cutting and raising the opposing surfaces of the main body 22 and the lid 23 into tongue shapes at several places, and by arranging these tongues alternately in the circumferential direction. A coil structure 25 is arranged on the outer periphery of this stator 24, and a rotor assembly 26 is arranged inside. This rotor assembly 26 has a rotor 29 that is magnetized with different polarities alternately in the circumferential direction around an insulating boss 28 that is fitted onto a rotary output shaft 27. The coil structure 25 also includes a coil spool 30 around which a thin wire is wound, and a short cylindrical container-shaped coil frame 31 that houses the coil spool 30 and connects the thin wire to a terminal 32 provided in a part of the coil spool 30. It has

The coil frame 31 is made of a material having some elasticity such as a resin material, and a hole 31a through which the stator 24 is inserted is formed in the bottom surface of the coil frame 31. A tongue-shaped support piece 33 protruding toward the front is integrally formed. This support piece 33 has a recess 34a formed at its tip position, in other words, at a part 34 corresponding to the center position of the coil frame 31, and by supporting the lower end of the rotary output shaft 27 within this recess 34a, this part is configured as a bearing 34 at the bottom of the rotor assembly 26. Further, a bearing 35 that forms a pair with this bearing 34 and pivotally supports the upper part of the rotational output shaft 27
is fitted and supported within the central hole of the lid body 23, and restrains the rotary output shaft 27 in the radial direction. In the diagram, 3
6 is a gear fitted to the tip of the rotary output shaft 27.

According to the above configuration, the rotor assembly 26, in other words, the rotational output shaft 27, is radially restrained at the upper end by the bearing 35 but is freely supported in the axial direction, and the lower end is restrained by the bearing 34 in the radial direction. The bearings will be in contact with each other in the axial direction. In this state, the bearing 34 is elastically biased upward by the elastic force of the support piece 33, thereby biasing the rotary output shaft 27 in the upper axial direction. Therefore, the upper surface of the boss 28 of the rotor assembly 26 is brought into contact with the lower surface of the bearing 35, and this state is maintained even during rotation of the rotor assembly 26.

Therefore, the bearings 34, 35 and the rotor assembly 2
The play between the rotor assembly 26 and the stator 24 becomes zero due to the elastic force of the support piece 33.
This maintains the axial position of the rotor assembly in a constant state and prevents vibrations in the axial direction due to the rotational movement of the rotor assembly. As a result, noise caused by shaft vibration of the rotor assembly is prevented, and the coil structure 25 and case 21 are
It is possible to prevent the negative effects of vibration on the

As described above, according to the synchronous motor of the present invention, there is no need to provide a biasing means for preventing shaft vibration of the rotor assembly caused by a separate member, so the construction of the structure in which the motor is installed is simplified, reducing the number of parts and assembly man-hours. It has various practical effects, such as preventing an increase in the amount of carbon dioxide and making it easier to manufacture.

As described above, according to the synchronous motor of the present invention, one of the pair of bearings that pivotally supports the rotor assembly is provided with a biasing means for elastically biasing the rotor assembly in the direction of the other bearing. Absorbs the axial play of the motor and prevents shaft vibration, reducing motor noise and improving reliability.In addition, the number of parts is reduced compared to conventional products, resulting in smaller size and lower costs. It has the effect of being able to do it.

[Brief explanation of drawings]

Figure 1 is a cutaway front view of a conventional synchronous motor, Figure 2
The figure is a partially exploded perspective view of the synchronous motor of the present invention.
The figure is a longitudinal sectional view. 20...Synchronous motor, 21...Case, 24...
... Stator, 25 ... Coil structure, 26 ... Rotor assembly, 27 ... Rotation output shaft, 29 ... Rotor, 33 ... Support piece, 34, 35 ... Bearing, 37
... Bearing, 38 ... Compression spring.

Claims (1)

[Scope of utility model registration request] A case 21 consisting of a main body 22 shaped like a short cylindrical container and a lid 23 that fits into the opening thereof, and a plurality of stators 24 integrally formed from case constituent members so as to be arranged circumferentially inside the case. , a coil structure 25 consisting of a coil spool 30 provided on the outer periphery of the stator and a coil frame 31 formed of a resin material, etc.; In a synchronous motor equipped with a rotor assembly 26 rotatably supported, a hole 31a through which the stator is inserted is formed in the bottom of the coil frame, and a tongue-shaped support piece 33 protruding toward the center is integrally formed. A synchronous motor, characterized in that a recess 34a is provided at the tip of the support piece, and this recess is configured as a lower end bearing of the rotary output shaft 27 of the rotor assembly whose upper end is supported by a bearing 35 provided on the lid. .