JPH06137324A - Electric motor - Google Patents

Abstract

PURPOSE:To reduce the number of part items, simplify constitution, and also realize downsizing in an electric motor to reduce a thrust load received by a thrust bearing. CONSTITUTION:Thrust load receiving magnetic pole parts 17 having single polarity are arranged in an inner peripheral part of a main magnetic pole part 16 of a rotor magnet 12, and a thrust load received by a thrust bearing is reduced by resiliency between it and a thrust load receiving magnet arranged in a stator. Since N pole 17a parts having the same polarity with the main magnetic pole part 16 among the thrust load receiving magnetic pole parts 17 are magnetized simultaneously with the main magnetic pole part 16, magnetic flux density of the parts can be increased more than when the whole thrust load receiving magnetic pole parts 17 are magnetized separately from the main magnetic pole part 16, so that the resiliency between it and the thrust load receiving magnet can be increased because of this.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor configured to reduce the thrust load received by a thrust bearing.

[0002]

2. Description of the Related Art For example, Japanese Patent Publication No. 4-1574 discloses that
In an electric motor in which a rotor provided with a rotor magnet is rotatably provided on a stator via a thrust bearing, annular thrust load receiving magnets are opposed to and repulsive to the stator side and the rotor side, respectively. It is disclosed that the thrust load received by the thrust bearing is reduced by the magnetic repulsive force between these thrust load receiving magnets.

[0003]

However, in the above-mentioned structure, since it is necessary to provide dedicated thrust load receiving magnets on the stator side and the rotor side, respectively, the number of parts increases and the structure becomes complicated. As a result, there is a drawback that it is difficult to miniaturize.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric motor which can reduce the thrust load received by the thrust bearing, can reduce the number of parts, simplify the structure, and can reduce the size. .

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to an electric motor in which a rotor provided with a rotor magnet is rotatably provided on a stator via a thrust bearing. A single polarity thrust load receiving magnetic pole portion is magnetized on an inner peripheral portion or an outer peripheral portion of the magnetic pole portion, and a portion of the thrust load receiving magnetic pole portion having the same polarity as the main magnetic pole portion is the main magnetic pole portion. The magnet is configured to be magnetized at the same time as the magnetic pole portion, and the stator is provided with a magnet for thrust load receiving which is opposed to and repels the magnetic pole portion for thrust load receiving. .

[0006]

According to the above structure, the thrust load received by the thrust bearing is reduced by the repulsive force between the thrust load receiving magnetic pole portion provided on the rotor magnet and the thrust load receiving magnet provided on the stator. can do.

At this time, since the thrust load receiving magnetic pole portion on the rotor side is provided integrally with the rotor magnet,
The number of parts can be reduced compared to the case where a dedicated thrust load bearing magnet is provided on the rotor side.

Further, since a portion of the thrust load receiving magnetic pole portion having the same polarity as the main magnetic pole portion is magnetized at the same time as the main magnetic pole portion, half of the thrust load receiving magnetic pole portion is the main magnetic pole portion. Since the magnetic flux density is the same as that of, the magnetic flux density of that portion can be increased compared to the case where the entire thrust load bearing magnetic pole portion is magnetized separately from the main magnetic pole portion, and accordingly, the thrust load bearing magnet The repulsive force between the two can be increased, and the thrust load received by the thrust bearing can be further reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, in FIG. 2 showing the overall configuration, a stator 1 includes a housing 3 integrally including a tubular portion 2.
And a printed wiring board 5 provided on the housing 3 with a stator yoke 4 interposed therebetween, and a stator coil 6 adhered and fixed on the printed wiring board 5, and the thrust coil is formed in the lower portion of the cylindrical portion 2. A bearing 7 is provided.

On the other hand, the rotor 8 has a rotating shaft 9 which is inserted into the cylindrical portion 2 and whose lower end is rotatably supported by the thrust bearing 7, and a mounting portion 10 on the upper outer peripheral portion of the rotating shaft 9.
Formed on the lower surface of the rotor yoke 11, an annular rotor magnet 12 adhered and fixed to the lower surface of the rotor yoke 11 so as to face the stator coil 6, and a printed wiring board 5 formed on the outer peripheral portion of the rotor yoke 11. It is composed of an FG pattern 13 for frequency power generation (not shown) and an FG magnet 13 fixedly adhered so as to face it.

The lower end of the rotating shaft 9 is formed in a spherical shape and is supported by the thrust bearing 7, and a large number of grooves 14 are formed on the outer peripheral surface of the rotating shaft 9 and the grooves 14 are formed. A dynamic pressure bearing 15 is configured between the inner circumferential surface of the tubular portion 2 and the inner circumferential surface.

Therefore, the rotor 8 is rotatably provided on the stator 1 via the thrust bearing 7 and the dynamic pressure bearing 15.

Now, as shown in FIG. 1, the rotor yoke 12 has N poles 16a and S poles 16b alternately arranged in the circumferential direction.
The main magnetic pole portion 16 is magnetized in total of 8 poles for each pole, and a thrust load receiving magnetic pole portion 17 having a single polarity of N pole in FIG. 1 is magnetized on the inner peripheral portion of the main magnetic pole portion 16. Then configured.

Here, of the thrust load receiving magnetic pole portion 17, the portion having the same polarity as the main magnetic pole portion 16, that is, the N pole 17a portion corresponding to the N pole 16a of the main magnetic pole portion 16, is
The portion of the main magnetic pole portion 16 that is magnetized integrally and simultaneously with the N pole 16a and has a polarity different from that of the main magnetic pole portion 16, that is, the N pole 17b portion corresponding to the S pole 16b of the main magnetic pole portion 16 is the main magnetic pole. It is magnetized separately from the S pole 16b of the portion 16.

On the stator 1 side, an annular thrust load receiving magnet 18 is provided via a yoke 18a so as to face the thrust load receiving magnetic pole portion 17 provided on the rotor magnet 12. The thrust load receiving magnet 18 is magnetized in a single pole having an N pole on the upper surface side so that a repulsive force acts on the thrust load receiving magnetic pole portion 17.

In the above structure, when the stator coil 6 is energized, the rotor coil 8 and the magnetic flux of the main magnetic pole portion 16 of the rotor magnet 12 cause the rotor 8 to rotate about the rotary shaft 9.

At this time, the thrust load of the rotor 8 is received by the thrust bearing 7 via the rotary shaft 9, and the thrust load receiving magnetic pole portion 17 provided on the inner peripheral portion of the rotor magnet 12 and the stator 1 side. It is received by the magnetic repulsive force acting between the thrust load receiving magnet 18 and the magnet.

Accordingly, since the thrust load is received by the thrust bearing 7 by the repulsive force between the thrust load receiving magnetic pole portion 17 and the thrust load receiving magnet 18, the thrust load received by the thrust bearing 7 can be reduced. It is possible to reduce wear between the bearing 7 and the bearing 7, improve reliability, and extend life.

According to the above-described embodiment, since the thrust load receiving magnetic pole portion 17 on the rotor 8 side is provided integrally with the rotor magnet 12, when a dedicated thrust load receiving magnet is provided on the rotor 8 side. In comparison, the number of parts can be reduced, the structure can be simplified, and the size can be reduced.

Here, when the rotor magnet 12 is provided with a thrust load receiving magnetic pole portion, as shown in FIG. 3 as a comparative example of the present invention, an annular thrust load is applied to the inner peripheral portion of the main magnetic pole portion 16 of the rotor magnet 12. Receiving magnetic pole part 1
It is conceivable to magnetize 9 separately from the main magnetic pole portion 16 by a single pole.

Generally, when magnetizing a magnet, there is a circumstance that the smaller the magnetized area is, the smaller the magnetizing force is because of the relationship between the magnetizing yoke and winding used, magnetic leakage, and the like. When the thrust load receiving magnetic pole portion 19 is monopolarly magnetized separately from the main magnetic pole portion 16 as in the comparative example of FIG. 3, the thrust load receiving magnetic pole portion 19 has a magnetized area larger than that of the main magnetic pole portion 16. Therefore, the magnetic flux density of the thrust load receiving magnetic pole portion 19 becomes smaller than the magnetic flux density of the main magnetic pole portion 16.

On the other hand, in the case of this embodiment, the N pole 17a portion of the thrust load receiving magnetic pole portion 17 having the same polarity as the main magnetic pole portion 16 is magnetized at the same time as the main magnetic pole portion 16. As a result, half of the thrust load receiving magnetic pole portion 17 has the same magnetic flux density as the main magnetic pole portion 16, so that the entire thrust load receiving magnetic pole portion 19 is magnetized separately from the main magnetic pole portion 16 (see FIG. 3). The magnetic flux density of the N pole 17a can be increased, and accordingly, the repulsive force between the thrust load receiving magnetic pole portion 17 and the thrust load receiving magnet 18 can be increased, and the thrust load receiving magnet 18 can be increased. The thrust load received by the bearing 7 can be further reduced.

Further, since there is no boundary between the N pole 16a portion of the main magnetic pole portion 16 and the thrust load receiving magnetic pole portion 17, there is no loss area contributing to the generated torque as compared with the comparative example. Therefore, there is also an advantage that the driving torque is increased and the efficiency of the motor is improved.

In the above embodiment, the rotor magnet 12 was excited when the thrust load receiving magnetic pole portion 17 was provided on the inner peripheral portion of the main magnetic pole portion 16, but FIG. 4 shows another embodiment of the present invention. As shown as an example, the single-polarity thrust load receiving magnetic pole portion 20 may be provided on the outer peripheral portion of the main magnetic pole portion 16.

Also in this case, the thrust load bearing magnetic pole portion 2
The portion of the N pole 20a having the same polarity as that of the main magnetic pole portion 16 of 0 is magnetized simultaneously and integrally with the N pole 16a of the main magnetic pole portion 16, and the portion of the N pole 20b having a different polarity from the main magnetic pole portion 16 is The main pole portion 16 is magnetized separately from the S pole 16b.

[0026]

As is apparent from the above description, according to the present invention, the rotor magnet is integrally provided with the thrust load receiving magnetic pole portion, so that the rotor side is provided with the dedicated thrust load receiving magnet. Compared with the case, the number of parts can be reduced, the configuration can be simplified, and eventually the size can be reduced.

Since the portion of the thrust load receiving magnetic pole portion having the same polarity as the main magnetic pole portion is magnetized at the same time as the main magnetic pole portion, the entire thrust load receiving magnetic pole portion is the main magnetic pole portion. Compared with the case of magnetizing separately, the magnetic flux density of that part can be increased, and the repulsive force between it and the thrust load receiving magnet can be increased accordingly, further reducing the thrust load received by the thrust bearing. You can

[Brief description of drawings]

FIG. 1 is a plan view of a rotor magnet showing an embodiment of the present invention.

[Fig. 2] Front view of the entire fracture

FIG. 3 is a diagram corresponding to FIG. 1 showing a comparative example with respect to the present invention.

FIG. 4 is a view corresponding to FIG. 1 showing another embodiment of the present invention.

[Description of Reference Signs] 1 is a stator, 7 is a thrust bearing, 8 is a rotor, 12 is a rotor magnet, 15 is a dynamic pressure bearing, 16 is a main magnetic pole part,
Reference numeral 17 is a thrust load receiving magnetic pole portion, 18 is a thrust load receiving magnetic pole, and 20 is a thrust load receiving magnetic pole portion.

Claims (1)

[Claims] 1. A rotor provided with a rotor magnet, which is rotatably provided on a stator via a thrust bearing, wherein an inner peripheral portion or an outer peripheral portion of a main magnetic pole portion composed of an N pole and an S pole of the rotor magnet. A magnetic pole portion for receiving a thrust load having a single polarity, and a portion of the thrust load receiving magnetic pole portion having the same polarity as the main magnetic pole portion is magnetized at the same time as the main magnetic pole portion. The electric motor, wherein the stator is provided with a magnet for thrust load receiving that is magnetized so as to face the thrust load receiving magnetic pole portion and repel it.