JPS6077659A - Rotor of magnet rotary motor - Google Patents

Abstract

PURPOSE:To reduce the size and to effectively utilize a magnet by forming a housing of a rotor of a nonmagnetic material, and mounting the magnet through a yoke, thereby reducing a leakage magnetic flux. CONSTITUTION:A rotor housing 10 made of a nonmagnetic material has a skirt portion 10b integral with a bottom 10a mounted with a rotational shaft. A magnet 3 is mounted through a yoke 11 made of a ferromagnetic material inside the housing 10. A plurality of magnets 3 are magnetized axially, contacted with the inside of the skirt portion 10b of the housing 10, and annularly mounted as a whole in close contact with the surface of the yoke 11. From this construction, leakage magnetic flux can be reduced, the size of the magnets can be reduced, and the magnets can be effectively utilized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotor for a magnet rotating electric motor.

Conventional configuration and its problems A general magnet rotation type electric motor will be explained based on FIG. 1.

In Fig. 1, 2 is a rotor housing, and a skirt portion 2 that also serves as a yaw and is integrated with a bottom portion 2a into which the rotating shaft 1 is fitted.
b, and holds a plurality of magnets 3 (having an annular shape as a whole and having a plurality of poles) that are inscribed in the skirt portion 2b and magnetized in the axial direction.

Above rotating shaft 1. Rotor/・Ujifugu 2. The magnets 3 are collectively called a rotor.

Reference numeral 6 denotes a stator, which is disposed facing the magnet 3 and is constructed by providing a slot in the axial direction in a toroidally wound core, and winding the drive coil 4 around the core. Reference numeral 6 denotes a housing that holds the stator 6 and also holds the bearing Y, and this bearing 7 receives the rotating shaft 1. Reference numeral 8 denotes a sensor for detecting the magnetic pole position of the magnet, and includes one circuit (not shown) for generating a rotating magnetic field in the stator in response to a signal from this sensor. It prevents 9-stripes.

The above is an example of the structure of a magnet rotating electric motor, and FIG. 2 shows an overall sectional view of a conventional rotor.

As mentioned above, this rotor has a bottom portion 2a on which the rotating shaft 1 is fitted.
A rotor housing 2 has a skirt portion 2b integral with the rotating shaft and a rotating shaft fitting portion 2C, and a plurality of magnets 3 are held inscribed in the skirt portion 2b. Since the bottom 2a of the rotor housing 2 also serves as a yoke, the entire rotor housing 2 is made of ferromagnetic material.

The functions of the rotor housing 2 will now be described.O Needless to say, the function of the rotor housing 2 is to transmit the rotational force received by the magnets to the rotating shaft 1 in response to the rotating magnetic field generated in the stator.

Another important function is to prevent the magnets from scattering by absorbing the centrifugal force that the plurality of magnets 3 receive as they rotate. The rotor housing 2 has a continuous annular structure, and when subjected to centrifugal force, the centrifugal force mainly acts as a force in the circumferential direction of the rotor housing 2, and the rotor housing 2 is subjected to tensile stress in the circumferential direction. will receive. Therefore, the strength of the rotor housing material itself is sufficient to withstand the above-mentioned tensile stress. However, since the magnet 3 is made up of a plurality of pieces and has a continuous annular shape, it does not receive tensile stress against centrifugal force.

Therefore, the centrifugal force that the magnet 3 receives is generated as a radial force and acts on the skirt portion 2b of the rotor housing 2,
In addition to the tensile stress due to the centrifugal force of the skirt portion 2b due to its own weight, the skirt portion 2b is subjected to further tensile stress due to the centrifugal force VC applied to the magnet 3.

However, if you use a continuous annular structure instead of multiple magnets, the centrifugal force that the magnet receives will naturally be applied to the magnet itself as a tensile stress, and it will be able to withstand 1 ohm [depending on the strength of the magnet, but generally speaking Magnet 1: 1 lower strength than A, and can withstand high centrifugal force at high speed rotation! 1- There is no such thing and it is easily damaged. For this reason, magnets used for heavy speed rotation are generally divided into a plurality of pieces so that the magnet's own material VC is not subjected to tensile stress in the circumferential direction due to far-flooding and force.

As described above, the rotor housing 2 VC has the function of receiving the centrifugal force applied to the magnet 3 and preventing the magnet from scattering. Furthermore, as described above, the bottom portion 2a of the rotor housing 2 VC is also used as a yoke.

The reason why the rotor housing 2 is made of a ferromagnetic material and has a bottom part 2a and a skirt part 2b as in the conventional example is that the bottom part 2a also serves as a yoke, and It can be seen that this is because the skirt portion 2b receives the centrifugal force.

However, in the case of the conventional example, as shown in the partially enlarged view of FIG. 3, the leakage magnetic circuit is composed of a loop A consisting of a fitting part 2c and a bottom part 2a, and a loop B consisting of a skirt part 2b and a bottom part 2a. However, there is a drawback that the effective magnetic flux density in the portion of the stator 6 facing the magnet is reduced. Therefore, the degree of effective utilization of the magnet 3 was reduced.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, makes more effective use of magnets, and also absorbs centrifugal force applied to the magnets.
This provides a rotor that can withstand high-speed rotation.

Structure of the Invention The rotor of the magnet-rotating electric motor of the present invention has a rotor housing made of a non-magnetic material that has a bottom portion into which a rotating shaft is fitted and an integral skirt portion, and a plurality of magnets are attached to the shaft through an annular yoke. The magnets are arranged and fixed in an annular shape so that there are multiple poles in the direction, thereby reducing leakage magnetism.

DESCRIPTION OF EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

In Fig. 4, 1Q is a rotor housing made of a non-magnetic material, which has a bottom part 10a into which the rotating shaft is fitted, and an integral skirt part 10b; O and 10c are the fitting parts into which the rotating shaft is fitted. Demeru 011 is a yoke made of ferromagnetic material.
- It is attached to the inside of the Uji pufferfish 1o in a state where it is held between the Uzi bottom part 10a and the magnet 3. Reference numeral 3 designates a plurality of magnets magnetized in the axial direction, which are inscribed in the skirt portion 10b of the housing 10 and are mounted in close contact with the yoke 11 in an annular shape as a whole.

The rotor of the magnet-rotating electric motor of the present invention having the above-described structure is unlikely to cause leakage magnetic circuits (loops A, B) as shown in FIG. Therefore, since the skirt portion 2b and the fitting portion 2C, which were integrally formed with the yoke in the conventional example, are made of non-magnetic material, it is difficult to form a leakage magnetic circuit (loops A and B). Incidentally, as a result of actually measuring the magnetic flux density of this configuration, a magnetic flux density that was approximately 10% higher than that of the conventional example was obtained when the air gap (facing distance between the stator and the magnet) was the same as that of the conventional example.

At first glance, the addition of the yoke 11 may seem to increase the cost of amplifier VC, but the magnet can be made smaller accordingly. Especially when using expensive magnets such as rare earth magnets, the cost of making the magnet smaller is greater than the increase in the cost of the yoke. Down is much larger and its usefulness is greater.

Further, as shown in FIG. 6, a skirt portion 1 is integrally attached to the yoke 11
2, the leakage magnetic flux becomes larger than in the case of FIG. 4, but it is smaller than in the conventional example, and is an effective means for reinforcing the skirt portion 10b of the housing 10, which is subjected to the centrifugal force of the magnet.

Therefore, it is effective at higher speed rotation.

Furthermore, as shown in FIG. 6, by making the skirt portion 12'b shorter than that in FIG. 5, that is, shorter than the axial thickness of the magnet 3, the resistance of the leakage magnetic circuit (FIG. 3B) increases. , the leakage magnetic flux is reduced. Of course, even in this case, it goes without saying that the skirt portion 10b of the housing 10, which is subjected to the centrifugal force of the magnet, is reinforced.

Effects of the Invention As described above, the rotor of the magnet-rotating electric motor of the present invention has a housing made of a non-magnetic material and the magnets are attached through the yoke, which reduces leakage magnetic flux and makes the magnets smaller. It can be used effectively, and is also useful in reducing costs.

In addition, as shown in the other embodiments (/C1), it is possible to provide a rotor configuration that not only reduces leakage magnetic flux but also absorbs all the centrifugal force that the magnets can receive, and its usefulness is great.Especially in high-speed rotation, i.e. This is particularly useful when subjected to high centrifugal force.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an example of a magnet-rotating electric motor, Fig. 2 is a sectional view of a rotor of a conventional magnet-rotating electric motor, Fig. 3 is an enlarged view of the same part, and Fig. 4 is a magnet-rotating motor according to the present invention. FIG. 6 is a cross-sectional view showing one embodiment of a rotor of a type electric motor, and FIG. 6 is a cross-sectional view showing another embodiment of the same rotor. 10...Housing made of non-magnetic material, 1
1...Yoke, 12...Yoke having a skirt portion.

Claims (2)

[Claims] (1) In a rotor housing made of a non-magnetic material that has a bottom portion into which a rotating shaft is fitted and an integral skirt portion, multiple magnets are arranged in an annular shape so as to form multiple poles in the axial direction via an annular yoke. The rotor of a magnet-rotating electric motor is fixed. (2) A rotor for a magnet rotary electric machine according to claim 1, wherein the annular yoke has an integral skirt portion.