JPH10178752A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of magnets used when the magnets are installed on a yoke and the magnets are disposed on the yoke, so that the yoke and the magnets face a coil. SOLUTION: N single-pole magnetized magnets 10 (n is a natural number) are placed on a yoke 8 at equal intervals, so that all the magnets 10 face a coil on the same magnetic pole side. Parts 16 of the yoke 8 are turned by the magnets 10 into n magnetic poles, opposite to the magnetic poles of the magnets 10 facing the coil. Thereby 2n poles are provided as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor using a magnet for a magnetic pole of a rotor or a stator.

[0002]

2. Description of the Related Art Some relatively small motors use a ring-shaped or cylindrical magnet (permanent magnet) multipolarly magnetized on a stator or a rotor. However, in a relatively large motor using a high magnetic force magnet, it is difficult to perform multipolar magnetization on a ring-shaped or cylindrical magnet. Therefore, a single-pole magnetized magnet is used for each magnetic pole.

FIG. 7 schematically shows a rotor a in a conventional motor using a plurality of single-pole magnetized magnets as described above. That is, the rotor a
A substantially tile-shaped magnet b monopolarly magnetized for each of the magnetic poles;
are arranged at equal intervals on the inner peripheral surface of the substantially cylindrical rotor yoke c such that N poles and S poles alternately face coils (not shown) of the stator d.

[0004]

By the way, in the motor using the rotor a, the same number of magnets having the N pole and the S pole monopolarly magnetized on the surface of the rotor yoke c facing the coil of the stator d. In other words, a total number of magnets is required for the number of magnetic poles of the rotor a, and as the number of magnetic poles of the rotor a increases, more magnets are required.

Accordingly, an object of the present invention is to reduce the number of magnets used in a motor in which magnets are used as rotors or stators as magnetic poles, even though the number of magnets is the same.

[0006]

In order to solve the above-mentioned problems, a motor according to the present invention comprises n (n is a natural number) single-pole magnetized magnets such that the same magnetic pole faces the coil. The magnets are arranged at equal intervals on the yoke, and a part of the yoke becomes n magnetic poles opposite to the magnetic pole of the magnet on the side facing the coil by the magnet, thereby having 2n poles as a whole. .

Therefore, it is possible to produce a motor having 2n poles using n magnets.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the motor of the present invention will be described below based on the following embodiments and modifications.

FIGS. 1 and 2 show a first embodiment in which the motor of the present invention is applied to an outer rotor type 8-pole motor.

In the following description, when referring to the up, down, left, and right directions, the first embodiment refers to the up, down, left, and right directions in FIG. 1 and the second embodiment to FIG.

The motor 1 includes a bearing chassis 2, which is a bearing member, a stator 3, a rotor 4, and the like. The bearing chassis 2 has a container shape that opens upward, and a substantially cylindrical bearing member 5 is attached to the center of the bearing chassis 2 so as to protrude upward.

The stator 3 has a plurality of coils 6, 6,... Arranged and fixed at equal intervals in the circumferential direction around a bearing member 5 in the bearing chassis 2.

The rotor 4 has a disk-shaped main part 7 made of synthetic resin, a short cylindrical rotor yoke 8 fixed to the lower part of the main part 7, and a circumferential direction of an inner peripheral surface 9 of the rotor yoke 8. , And a rotating shaft 11 whose upper end is press-fitted and fixed to the center of the main portion 7 and protrudes downward. It consists of:

That is, the rotor yoke 8 has a substantially cylindrical shape with a short axial length, and its inner peripheral surface 9 has four magnets 10 for accommodating the magnets 10, 10,.
The vertically long magnet housing grooves 12, 12,..., Which are concave portions having the same shape as the outer shapes of 0, 10,..., Are formed continuously from the upper end to the lower end. The magnets 10, 10,... Have a vertically long, substantially tile-like shape, that is, one of a cylinder obtained by equally dividing a cylinder vertically in the axial direction. And the magnets 10, 10, ...
Are monopolarly magnetized (N pole in this embodiment) to the N-pole or S-pole end faces 13, 13,.
As a result, the opposite back surfaces 14, 14,... Become S poles or N poles (S poles in this embodiment), and FIG.
As shown in FIG. 3, the one end faces 13, 13,... In the magnet storage grooves 12, 12,.
Are housed and fixed so as to face the inner circumferential direction of the rotor yoke 8. At this time, the magnets 10, 10,...
Are fixed to the inner surface 9 of the rotor yoke 8 when fixed to the rotor yoke 8 to form a uniform surface with no steps.

The magnets 10, 10,... Are placed in the magnet storage grooves 12, 12,.
Are stored, the magnet storage grooves 12, 12,...
, Are magnets 10, 10,.
Are magnetized to be N poles in contact with the back surfaces 14, 14,..., Which have become S poles, thereby forming two magnets adjacent to the inner peripheral surface 9 as shown in FIG. 1
The regions 16, 16,... Sandwiched between 0, 10 are S poles, and the rotors have 8 (2n) poles even though only 4 (n) magnets 10, 10,. 4 will be formed.

FIG. 3 shows a first modification 20 of the rotor yoke in the first embodiment.

In each of the following modifications, only the shape of the rotor yoke is different. Therefore, the same parts as those in the first embodiment are the same as the reference numerals assigned to the same parts in the first embodiment. The description is omitted by attaching the reference numerals.

That is, as shown in FIG.
0 is a substantially cylindrical shape having a short axial length, and its inner peripheral surface 2
1 includes four magnet storage grooves 22, which are recesses for storing the magnets 10, 10,.
Are formed continuously from the upper end to the lower end. Further, the inner peripheral surface 21 is partially cut out along the opening edges of the magnet storage grooves 22, 22,.
Are continuously formed from the upper end to the lower end, so that the inner peripheral surface 21 and the opening edges of the magnet housing grooves 22, 22,.

The magnet storage grooves 22, 22,... Of the rotor yoke 20 have magnets 10, 10,.
When the magnet is housed and fixed, the magnet housing groove 22,
The magnets 1 have bottom surfaces 24, 24,.
Back surfaces 14, 14,... Which are S poles of 0, 10,.
, And is magnetized to the N-pole, thereby being sandwiched between the magnets 10, 10,.
A part 25 of the inner peripheral surface 21 partitioned by 3,.
.. Become S poles and define an eight-pole rotor as if eight magnets were used.

Therefore, in the motor using the rotor yoke 20, the cogging can be reduced by the above-described shape of the rotor yoke 20, thereby making it possible to produce a motor with small torque ripple (torque fluctuation). Becomes

FIG. 4 shows a second modification 30 of the rotor yoke.

That is, the rotor yoke 30 has a substantially cylindrical shape having a short axial length, and its inner peripheral surface 31 is a magnet housing which is a concave portion for housing magnets 32, 32,. Grooves 33, 33,..., And between the magnet storage grooves 33, 33,.
34 are continuously formed in parallel from the upper end to the lower end of the rotor yoke 30.

The magnets 32, 32,...
Have a similar tile shape to the magnets 10, 10,... But have a smaller width than the magnets 10, 10,. Are smaller than the magnet housing grooves 12, 12,..., 22, 22,. And the magnets 32, 3
2,... Are unipolarly magnetized so that the end faces 35, 35,.

The magnet storage grooves 33, 33,... Of the rotor yoke 30 have magnets 32, 32,.
When the magnet is housed and fixed, the magnet housing grooves 33, 3
The bottom surfaces 36, 36,... Of the 3... Face the back surfaces 37, 37,. , Whereby the end faces 38, 38,.
Becomes an S pole, and an eight-pole rotor is defined. The end faces 38, 38, ... of the ridges 34, 34, ... facing the inner peripheral surface 31 side of the rotor yoke 30 are the end faces 35, 35, ... of the magnets 32, 32. Have the same amount of protrusion from the inner peripheral surface.

Therefore, in the motor using the rotor yoke 30, the cogging can be reduced by the above-described shape of the rotor yoke 30, thereby making it possible to produce a motor having a small torque ripple.

FIGS. 5 and 6 show the motor of the present invention applied to a so-called thrust-facing motor 40. FIG. That is, the motor 40 is arranged such that the rotor 41 and the stator (not shown) face each other in the axial direction of the rotation shaft.

As shown in FIG. 5, the rotor 41 has a substantially disk-shaped upper surface 4 opposed to the stator of a rotor yoke 42.
.. Are fixedly attached to four magnets 44, 44,.

That is, a shaft hole 45 is formed at the center of the rotor yoke 42, and a portion of the upper surface 43 around the shaft hole 45 is substantially petal-shaped by eight lines extending radially from the center of the rotor yoke 42. 8 alternately arranged
, One of the regions 46, 46,... Is recessed below the other region, and 9
The magnet storage recesses 46, 46,... Are separated by 0 degrees, so that the other area is relatively convex 47,
47, and so on.

The magnets 44, 44,.
The magnet housing concave portions 46, 46,.
The shape that fits snugly, that is, the shape seen from above is substantially petal-shaped. The magnets 44, 46,.
4, when attached, magnets 44, 44,
, And the projections 47, 47,.
··· The upper surfaces 49, 49,... Form a surface having a uniform height without a step. Also, the magnets 44, 4
, Are monopolarly magnetized so as to have N poles.

The magnets 44, 44,... Are provided in the magnet storage recesses 46, 46,.
.. when the magnet is housed and fixed, the magnet housing recess 46,
The bottom surfaces 50, 50,... Of the magnets 44, 44,.
・ It is magnetized in close contact with and becomes an N-pole.
Magnets 44 on the upper surface 43 of the rotor yoke 42,
, The upper surfaces 49 of the convex portions 47, 47,.
.. Become S poles, and an eight-pole rotor 41 in which N poles and S poles are alternately arranged is formed.

A rotor yoke having a complicated shape as shown in each of the above embodiments and modifications can be easily produced by a manufacturing method such as powder metallurgy.

A rotor having 2n poles by n magnets has a total magnetic flux density of 2n poles compared to a 2n pole rotor using 2n same magnets.
Although there is an adverse effect that the distance is reduced to one-half or less, since the arrangement interval of the magnets can be widened, it is particularly effective for a motor having magnetic poles with a fine pitch. And
As the yoke, it is also possible to use a magnetized yoke magnetized on a portion to be a magnetic pole.

[0033]

As is apparent from the above description, according to the first aspect of the present invention, n (n is a natural number) unipolar magnetized magnets all have the same magnetic pole. Are arranged at equal intervals on the yoke so as to face the coil, and a part of the yoke becomes n magnetic poles opposite to the magnetic pole of the magnet on the side facing the coil by the magnet,
As a result, the motor has 2n poles as a whole. Therefore, a motor having 2n poles can be formed by using a single type of magnet having n identical shapes and the same magnetic poles.

According to the second and third aspects of the present invention, the magnet may be mounted in a recess formed at regular intervals in the yoke, or the surface of the yoke facing the coil may be provided. The concave portion and the convex portion are alternately formed so that the convex portion becomes the magnetic pole, so that the yoke can also serve as the magnet positioning, and the occurrence of cogging and cogging can be achieved by arbitrarily changing the shape of the yoke. It is possible to make the rotation of the motor smooth by reducing the torque fluctuation caused by the occurrence of the vibration, and also to reduce the size of the magnet.

Further, in the invention described in claims 4 to 6, the yoke and the magnet constitute a rotor in an outer rotor type motor.
Since the coil is a stator coil, a motor having a rotor of 2n poles can be formed by n magnets.

It should be noted that the specific shapes and structures shown in the above-described embodiments are merely examples of the embodiments for carrying out the present invention, and the technical scope of the present invention is limited thereby. Should not be interpreted as

[Brief description of the drawings]

FIG. 1 shows a motor according to a first embodiment of the present invention together with FIG. 2, and FIG. 1 is a longitudinal sectional view.

FIG. 2 is an enlarged horizontal sectional view of a rotor.

FIG. 3 is an enlarged horizontal sectional view showing a first modification of the rotor.

FIG. 4 is an enlarged horizontal sectional view showing a second modification of the rotor.

FIG. 5 schematically shows a second embodiment of the motor of the present invention together with FIG. 6, which is a perspective view.

FIG. 6 is an enlarged sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is an enlarged horizontal sectional view showing a rotor of a conventional motor.

[Explanation of symbols]

1 ... motor, 3 ... stator, 4 ... rotor, 6 ... coil,
8 yoke, 10 magnet, 12 recess, 20 yoke, 22 recess, 30 yoke, 32 magnet,
33 ... recess, 34 ... projection, 40 ... motor, 41 ... rotor, 42 ... yoke, 44 ... magnet, 46 ... recess, 4
7 ... convex

Claims (6)

[Claims] 1. A motor in which a magnet is attached to a yoke, and the yoke and the magnet are arranged so as to face a coil. In the motor, n (n is a natural number) unipolar magnetized magnets are all the same. The magnetic poles are arranged at equal intervals on the yoke so as to face the coil, and a part of the yoke becomes n magnetic poles opposite to the magnetic pole of the magnet on the side facing the coil by the magnet,
A motor having 2n poles as a whole. 2. The motor according to claim 1, wherein the magnet is mounted in a recess formed in the yoke at regular intervals. 3. The motor according to claim 1, wherein concave portions and convex portions are alternately formed on a surface of the yoke facing the coil, and the convex portions serve as magnetic poles. 4. The motor according to claim 1, wherein the yoke and the magnet constitute a rotor in the outer rotor type motor, and the coil is a coil of a stator. 5. The motor according to claim 2, wherein the yoke and the magnet constitute a rotor in an outer rotor type motor, and the coil is a coil of a stator. 6. The motor according to claim 3, wherein the yoke and the magnet constitute a rotor in an outer rotor type motor, and the coil is a stator coil.