JPS6041823Y2 - Stator for motor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a stator for a motor that includes a yoke formed by sintering and a rare earth magnet.

In order to reduce the rotational torque unevenness of the rotor in motors whose magnets are made of permanent magnets, the conventional methods are to skew the rotor grooves, and to provide magnetic poles on a cylindrical magnetic body by skew magnetization. -21138) ■ Arrange multiple annular magnets so that their magnetic poles are shifted (Utility Model Publication No. 41-10729: Utility Model Number 54-2856)
No. 5) has been carried out, but the above method (2) is difficult to manufacture the rotor and wind the rotor, and is not suitable for mass production. This is undesirable for magnets whose performance deteriorates.

That is, rare earth magnets, which have recently been attracting attention due to their excellent performance, have a property in which the performance deteriorates when skew magnetization is performed, so this method is not suitable.

Method (2) was proposed to solve the above drawback, and although rare earth magnets can achieve substantially the same effect as skew magnetization, it requires multiple annular magnets. Therefore, it is uneconomical, especially when expensive rare earth magnets are used.

The reason for using an annular magnet is that it is difficult to accurately arrange a plurality of magnetized magnet pieces so as to have a predetermined skew.

On the other hand, soft iron is generally used for the yoke, but since this is difficult to process, conventionally there has been a method of integrally forming the yoke by sintering.

However, since the length of the yoke in the axial direction is long, holes (sparse parts) tend to occur near the center of the yoke, which deteriorates the performance of the motor.

An object of the present invention is to provide a stator for a motor that simultaneously solves the above-mentioned conventional drawbacks of magnets and yokes.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

In the drawing, 1 is a 4-pole DC motor, 2 is a rotor shaft,
3 and 4 are a commutator and a rotor core attached to the rotor shaft 2, and this rotor core 4 is formed of laminated iron plates,
A large number of grooves parallel to the rotor shaft 2 are provided on its outer periphery.

Reference numeral 5 denotes a winding placed in the groove of the rotor core 4.

6.7 is a bracket, which connects the rotor shaft 2 via the bearing 8.
is held in

9 is a brush fitted and held in a through hole bored in the bracket 6; 10.11 is a cylindrical yoke formed by sintering;
2 and 12' are rare earth magnets.

This rare earth magnet 12°12' is placed in a direction parallel to the rotor axis (
The cylindrical yoke 10.
11 by applying a magnetic field in the diametrical direction.

Further, the length of this magnet in the axial direction is such that it is longer than the length of the rotor core in the axial direction when the two magnets are not joined.

13 are four semicircular grooves provided on the outer peripheral surface of each yoke 10.11 in parallel with the axial direction thereof, and 14.15 are provided on the opposing end surfaces of both yokes 10.11, so that they can be secured to each other. This is a stepped portion with unevenness.

The rare earth magnets 12' are arranged alternately with N-5 poles on the inner peripheral surface of the yoke 11, and the center line in the rotor axis direction is aligned with each groove 1.
3, and the rare earth magnets 12 are placed on the inner peripheral surface of the yoke 10 in alternating N and S poles, and their center line in the rotor axis direction is slightly circumferentially away from each groove 13 (rotor core (preferably, the distance between the grooves for the windings 5 and 4 is about the same as that of the grooves for the windings 5).

In this coupled state of both yokes 10.11, both grooves are aligned with each other, so the rare earth magnets 12.12' of each yoke 10.11 are arranged with a slight deviation in the circumferential direction, that is, with a skew effect. There is.

16 is both yokes 10.11 and brackets 6.11 on both sides thereof.
7 and is engaged with the groove 13.

As detailed above, the motor stator of this example has 1
The rare earth magnets that make up each magnetic pole are divided into two pieces, and each rare earth magnet is fixed to a separate cylindrical yoke formed by sintering, so only a small amount of expensive rare earth magnets are required, and their positioning is also easy. Furthermore, there is no possibility that holes will be formed in the yoke and the characteristics will deteriorate.

In addition, especially in this embodiment, since four grooves 13 are provided in each of the grooves 13, when assembling, first align the grooves of both yokes so that the two yokes to which the rare earth magnets are fixed are connected by the attractive force of the magnets ( (Both yokes have different polarities adjacent to each other), then insert the rotor core fixed to the rotor shaft and shift the two yokes by 90 degrees (-load).
Both yokes do not repel even if magnets of the same polarity are adjacent to each other, making assembly work easier.

In other words, since the width of the rotor core is smaller than the sum of the axial widths of the magnets fixed to both yokes, the magnets of both yokes are attracted to the rotor core in a direction in which they approach each other, and the magnets of both magnetic poles There is no backlash.

Although several grooves 13 are provided in this embodiment, even if there are only n grooves, both yokes can be easily positioned.

As mentioned above, the present invention uses only a small amount of rare earth magnets, and furthermore, mutual positioning to obtain the skew effect is easy, and the characteristics of the yoke are also improved, which has a great effect.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view of a four-pole motor, Fig. 2 is a sectional view of the four-pole motor, Fig. 3 is a perspective view of a stator divided into two parts, and Fig. 4 is a perspective view of a four-pole motor. The figure shows a cross section of the stator in the coupled state. In the figure, 10.11 is a yoke, 12.12' is a rare earth magnet, and 13 is a groove.

Claims (1)

[Claims for Utility Model Registration] ■ At least two cylindrical yokes formed by sintering; ) rare earth magnets, wherein the yokes are arranged so that the magnets fixed to different yokes have the same polarity and are adjacent to each other, and are slightly offset in the circumferential direction. 2. The stator for a motor according to claim 1, wherein the rare earth magnet is formed by transverse magnetic field forming. 3. Each of the yokes has a cylindrical shape, and n or more grooves parallel to the axial direction are provided at equal intervals on the outer peripheral surface of the yoke, as set forth in claim 1 of the utility model registration claim. Stator for motor.