JPH05252677A - Permanent magnet rotor - Google Patents

Abstract

PURPOSE:To damp vibration functioning onto a permanent magnet and to retard transmission thereof by bonding a tubular permanent magnet to a shaft through a holding member comprising a movable magnetic body. CONSTITUTION:A movable annular magnetic body 4 is arranged on the outer peripheral surface of a holding member 3 press fit to a shaft 2 and sector permanent magnets 5a are bonded, while press fitting, to the outer periphery of the annular magnetic body 4. The movable annular magnetic body 4 serves as a yoke for magnetically coupling a plurality of sector permanent magnets 5a boded to the outer peripheral surface of the annular magnetic body 4 movably. According to the constitution, vibration functioning onto the permanent magnet 5a can be damped and transmission thereof to the shaft 2 can be retarded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small rotating electric machine, and more particularly to a permanent magnet type rotor of a small rotating electric machine which is required to prevent vibration due to rotation from being transmitted to a load shaft.

[0002]

2. Description of the Related Art The contents and structure of the prior art will be described with reference to FIGS. Conventionally, a single-phase induction motor has been often used as a power source for household electric appliances and office electric appliances, but in recent years, an electric motor equipped with a permanent magnet rotor for the purpose of controlling in consideration of energy saving. The method of operating in combination with the inverter circuit has been widely used. When driven by an inverter circuit, the winding of the stator facing the rotor has a PWM (pulse width modulation) current for the purpose of controlling the speed and torque of the electric motor, as disclosed in Japanese Patent Publication No. 63-26623. As a result, the pulsation of this current causes the torque generated by the rotor magnet to include a vibration component, which is transmitted to the load side via the shaft to excite the load object and cause noise.

Therefore, conventionally, as shown in FIG. 5, a vibration absorber 8 made of an elastic material such as rubber is interposed between the magnetic circuit forming portion including the permanent magnet 5 of the rotor and the shaft 2 to vibrate. The configuration was designed to shut off the power.

Although not shown in the drawings, as a means for holding the vibration absorber 8 in between, a device such as an end plate for holding the concentricity between the shaft and the permanent magnet may be used, as in Japanese Utility Model Publication No. Sho 63-21188. The use of a protective ring for mechanical protection of a permanent magnet that is easily seen and damaged is also a well-known technique as disclosed in Japanese Utility Model Publication No. 60-41821.

[0005]

The conventional structure as described above has a drawback in that it has many components and the manufacturing process is complicated, and the reliability is poor. That is, a coupling member for coupling and fixing to a shaft, a rotor yoke that is coupled to the coupling member via an elastic body such as rubber, a plurality of fan-shaped permanent magnets arranged on the outer periphery of the rotor yoke, The fan-shaped permanent magnet is composed of a protective ring that mechanically protects the outer periphery of the fan-shaped permanent magnet, and these are held by adhesive fixing with an adhesive, which causes a problem that the manufacturing process is complicated by the bonding process.

[0006]

A permanent magnet rotor according to the present invention comprises a cylindrical protective member made of a non-magnetic material, and a plurality of fan-shaped permanent magnets arranged in parallel on the inner peripheral surface of the cylindrical protective member. Alternatively, a cylindrical permanent magnet may be provided, and the permanent magnet may be coupled and fixed to the shaft through a holding member that is made of a flexible magnetic material such as rubber or plastic and has its inner and outer circumferences arranged in pressure contact. Composed.

[0007]

[Operation] In the above configuration, the flexible magnetic body has both the role of the yoke of the permanent magnet and the function of absorbing the vibration, and the structure is simple and acts on the permanent magnet. This brings about the effect of damping the vibration and making it difficult to transmit to the shaft.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a first embodiment of the present invention having a cylindrical protective member 6 made of a non-magnetic material and a plurality of fan-shaped permanent magnets 5a, and an outer periphery of a holding member 3 fixed to a shaft 2 by press fitting or the like. An annular magnetic body 4 having flexibility is disposed on the surface in a pressure contact state, and further, the permanent magnet 5a is fixedly attached to the outer peripheral surface of the annular magnetic body 4 in a pressure contact state. FIG. 2 is a side view of the example seen from the axial direction. The flexible annular magnetic body 4 acts as a yoke that magnetically couples the plurality of fan-shaped permanent magnets 5a fixed to the outer peripheral surface thereof, and also has flexibility so that it can be used as a permanent magnet. It acts so as to damp the acting vibration and make it difficult to transmit to the shaft.

FIG. 3 shows a second embodiment according to the present invention, in which a cylindrical permanent magnet 5b is used and a protection member 6 is not used. The coupling structure of the shaft 2, the holding member 3, and the flexible magnetic body 4 is the same as in the first embodiment, and FIG. 4 is a side view of the same as seen from the axial direction.

In the above-described embodiment, the coupling force between the rotor constituent members is maintained by the pressure contact force on the inner and outer peripheral surfaces of the annular magnetic body 4, but the coupling force is changed by making the engaging portion shape non-circular. It may be obtained by any method.

Further, in the structure using the cylindrical permanent magnet 5b of the second embodiment, there is concern about the strength of the cylindrical permanent magnet 5b in pressure contact with the magnetic body 4 having flexibility such as thin wall thickness. In this case, it is of course possible to use the cylindrical protection member 6 made of a non-magnetic material together as in the first embodiment.

[0012]

In the permanent magnet type rotor according to the present invention, since the yoke of the permanent magnet and the vibration absorbing member can be formed by one member, the structure can be simplified and the manufacturing process can be shortened. is there.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a first embodiment of the present invention.

2 is a side view of the example of FIG. 1. FIG.

FIG. 3 is a front sectional view showing a second embodiment of the present invention.

FIG. 4 is a side view of the example of FIG.

FIG. 5 is a front sectional view of an example of the prior art.

FIG. 6 is a side view of the example of FIG.

[Explanation of symbols]

 1: Rotor 2: Shaft 3: Holding member 4: Flexible magnetic material 5, 5a, 5b: Permanent magnet 6: Cylindrical protection member 7: Rotor yoke 8: Vibration absorber

Claims (5)

[Claims] 1. A cylindrical protective member made of a non-magnetic material and a plurality of sector-shaped permanent magnets arranged in parallel on the inner peripheral surface of the cylindrical protective member, wherein the plurality of sector-shaped permanent magnets have flexibility. A permanent magnet rotor characterized by being fixedly coupled to a shaft through a holding member made of a magnetic material. 2. A permanent magnet rotor, comprising a cylindrical permanent magnet, the cylindrical permanent magnet being fixedly coupled to a shaft through a holding member made of a magnetic material having flexibility. 3. The permanent magnet rotor according to claim 1, wherein the flexible magnetic body is a magnetic body using rubber as a base material. 4. The permanent magnet rotor according to claim 1, wherein the flexible magnetic body is a magnetic body based on plastic. 5. The magnetic material having flexibility is arranged and held in a state where the inner and outer circumferences are in pressure contact with each other.
4. The permanent magnet rotor described in 4.