JPH11252833A - Permanent magnet type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain demagnetization of a plurality of permanent magnets for field poles and pass higher current through a stator for higher output by forming the respective permanent magnets for field poles out of permanent magnet segments divided into a plurality of portions. SOLUTION: In a motor having a permanent magnet rotor, an effect of the rotating field of a stator 5 increases the temperature of permanent magnets 131 for respective field poles. By forming the permanent magnets 131 out of divided permanent magnet segments 181 , magnetic resistance at the permanent magnets 131 is increased to minimize eddy-current loss, thereby restraining heat generation of the permanent magnets 131 . It is thus possible to prevent the permanent magnets 131 from reaching demagnetizing temperature with lapse of operating time for relatively high output in a high-speed range of field weakening control. By covering the section between the respective permanent magnet segments 181 with an insulating layer 19. in an insulated condition, it is possible to conduct insulation between iron cores.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet motor having a permanent magnet rotor in which permanent magnets for field poles are embedded at a plurality of circumferentially spaced locations on an outer peripheral portion of an iron core having a circular cross section. About.

[0002]

2. Description of the Related Art Conventionally, such a rotor is already known, for example, from Japanese Utility Model Registration No. 2543165.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
At a plurality of locations spaced in the circumferential direction of the outer peripheral portion of the iron core, permanent magnets for field poles formed so as to have a substantially arc-shaped cross-sectional shape substantially corresponding to the outer peripheral surface of the iron core are embedded respectively. I have.

In the motor using such a permanent magnet rotor, the temperature of each field pole permanent magnet rises due to the influence of the rotating magnetic field of the stator, and decreases due to the rise in the temperature of the field pole permanent magnet. The output performance of the motor may be reduced due to the magnetism, and the output must be set low especially in the high rotation range of the field weakening control in which a rotating magnetic field orthogonal to the magnetic flux of the field pole permanent magnet works. . However, the above-mentioned conventional device does not take measures against such demagnetization due to the temperature rise.

The present invention has been made in view of such circumstances, and it has been made possible to suppress the demagnetization of a plurality of permanent magnets for field poles and to allow a higher current to flow through the stator to increase the output. It is an object to provide a permanent magnet type electric motor.

[0006]

In order to achieve the above object, the invention according to claim 1 is characterized in that permanent magnets for field poles are provided at a plurality of circumferentially spaced locations on an outer peripheral portion of an iron core having a circular cross section. In the permanent magnet motor having the embedded permanent magnet rotor, each field pole permanent magnet is constituted by a plurality of divided permanent magnet pieces.

According to such a configuration, the permanent magnet for each field pole is composed of a plurality of divided permanent magnet pieces.
The magnetic resistance of each field pole permanent magnet is increased, the eddy current loss is reduced, and the heat generation of the field pole permanent magnet can be suppressed, thereby contributing to an increase in the output of the electric motor. Moreover, depending on the combination of the permanent magnet pieces, the shape of the field pole permanent magnet can be freely changed.

According to the second aspect of the present invention, the whole of the plurality of permanent magnet pieces constituting the field pole permanent magnet is:
It is characterized in that it is covered with an insulating layer in a state where each permanent magnet piece is insulated from each other, and according to this configuration, while integrating the plurality of permanent magnet pieces and insulating between the iron core, Embedding and holding can be ensured.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 5 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of a permanent magnet type electric motor, and is a sectional view taken along line 1-1 in FIG. FIG. 3 is a front view as viewed in the direction of the arrow 2 in FIG. 1, FIG. 3 is a perspective view of the field pole permanent magnet with the insulating layer omitted, FIG. 4 is a temperature characteristic diagram of the field pole permanent magnet, and FIG. is there.

Referring to FIGS. 1 and 2, a permanent magnet type electric motor includes a stator 5 which forms a part of a casing (not shown), and a permanent magnet rotor 6 which is surrounded by the stator 5.
And a rotating shaft (not shown) is coaxially coupled to the rotor 5.

The iron core 7 of the stator 5 is formed in a ring shape by laminating a plurality of iron core plates, and is provided at a plurality of, for example, twelve locations at equal intervals in the circumferential direction of the inner circumference of the iron core 7. Are provided with salient poles 7a projecting radially inward. Moreover, a bobbin 8 made of a synthetic resin is mounted on the iron core 7, and the salient poles 7 a.
Are wound around via the bobbin 9.

The permanent magnet rotor 6 includes a rotor body 11 and
An iron core 12 fixed to the rotor main body 11 and a plurality of, for example, 12
And permanent magnets 13 ₁ for field poles.

The rotary core body 11 includes a cylindrical portion 11a, a support flange portion 11b extending radially outward from an outer surface of one end in the axial direction of the cylindrical portion 11a, and a radially extending inner surface of the cylindrical portion 11b. A connecting flange 11c extending inward is provided integrally, and a rotating shaft (not shown) is coaxially connected to the connecting flange 11c.

The iron core 12 is formed by laminating a plurality of iron core plates into a ring shape surrounding the cylindrical portion 11a, and one end of the iron core 12 in the axial direction is brought into contact with the support flange 11b. . A ring-shaped support plate 1 surrounding the other axial end of the cylindrical portion 11a is provided on the other axial end of the iron core 12.
4 is abutted. Moreover, a plurality of bolts 15 each having an engagement portion 15a at one end for engaging with the outer surface of the support flange portion 11b are provided at a plurality of, for example, six, locations spaced in the circumferential direction of the rotor main body 11, and 11b, the core 12 and the support plate 14
Nuts 16 are attached to the other ends of the bolts 15 projecting from
Is screwed and tightened, whereby the iron core 12 is fixed to the rotor main body 11.

At twelve places at equal intervals in the circumferential direction of the outer periphery of the iron core 12, mounting holes 17 extending along the axial direction of the iron core 12 are provided between both ends of the iron core 12 in the axial direction. Each of the field pole permanent magnets 13 ₁ is embedded in the iron core 12 so as to be inserted into each of the mounting holes 17. Moreover, the positions of the mounting holes 17 are set so that a part of both ends of the field pole permanent magnets 13 ₁ abut on the support flange 11b and the support plate 14, and the field pole permanent magnets 13 _{1 are formed.} Are prevented from being detached from the mounting holes 17 by the support flange 11b and the support plate 14.

In FIG. 3, the field pole permanent magnet 13
₁ is, for example, 4 divided along the circumferential direction of the iron core 12.
The entire permanent magnet pieces 18 ₁ are covered with an insulating layer 19 ₁ . That is, each of the permanent magnet pieces 18 ₁ .
Whole, will be covered with an insulating layer 19 ₁ in a state where the insulation between the permanent magnet pieces 18 ₁ ... mutual.

Next, the operation of the first embodiment will be described. In the motor using the permanent magnet rotor 6, the permanent magnets 13 for each field pole are affected by the rotating magnetic field of the stator 5.
₁ ... are those temperature increases, in particular, for field pole intended to stator 5 comprises a coil 9 ... salient pole concentrated winding in the magnetic flux change of the rotating magnetic field is relatively large, as in this embodiment The temperature of the permanent magnets 13 ₁ ... Has a remarkable tendency to rise, and in the conventional type provided with the undivided field permanent magnets, as shown by a broken line in FIG. The magnet will reach the demagnetization temperature. However, since the permanent magnet 13 ₁ ... for field pole is composed of divided permanent magnet pieces 18 ₁ ... was, to reduce the eddy current loss of the magnetic resistance of the permanent magnet 13 ₁ ... for field pole as a large, field poles Of the permanent magnets 13 ₁ ... Can be suppressed. Therefore, as shown by the solid line in FIG. 4, it is possible to prevent the field pole permanent magnets 13 ₁ from reaching the demagnetizing temperature even after the operation time elapses.

If the permanent magnet for the field pole reaches the demagnetizing temperature, the output performance of the motor may be reduced. In particular, the high rotation range of the field weakening control in which a rotating magnetic field orthogonal to the magnetic flux of the permanent magnet for the field pole acts. In this case, the output must be set low as shown by the broken line in FIG. 5, but as described above, by suppressing the heat generation of the field pole permanent magnets 13 ₁ ... As shown by the solid line in FIG. In addition, it is possible to obtain a relatively high output in a high rotation range of the field weakening control.

The whole of the plurality of permanent magnet pieces 18 ₁ ... Constituting the field pole permanent magnet 13 ₁ is made up of the respective permanent magnet pieces 18 _1.
... so are covered by the insulating layer 19 ₁ between mutually insulated state, while allowing a plurality of permanent magnet segments 18 ₁ ... integrated by the field pole permanent magnet 13 ₁ structure of, between the core 12 It can achieve insulation, moreover insulating layer 19 ₁ field pole permanent magnet 13 to the core 12 by the elastic force exerted
₁ ... Can be securely held.

[0021] As a second embodiment of the present invention, as shown in Figure 6, the permanent magnet 13 ₂ is a field pole, the iron core 12 three example divided along the axial direction (see FIG. 1 and FIG. 2) Of the permanent magnets 18 ₂ ... May be covered with an insulating layer 19 ₂ .

FIG. 7 shows a third embodiment of the present invention.
Corresponding to the outer peripheral surface of the iron core 12 (see FIGS. 1 and 2)
Permanently formed to have an arc-shaped cross section
Magnet piece 18_ThreeAnd the permanent magnet piece 18_ThreeOn both sides in the circumferential direction
Prismatic permanent magnet pieces adhered via adhesives 20, 20
18_Four, 18_FourAnd permanent magnet for field pole 13_ThreeIs composed
The permanent magnet piece 18 may be used._Three, 18_Four, 18
_FourThe whole is the insulating layer 19 _ThreeCovered.

As described above, the field pole permanent magnet 13_ThreeMultiple
Permanent magnet piece 18_Three, 18_Four, 18 _FourAs consisting of
Of the permanent magnet pieces 18_Three, 18_Four, 1
8_FourField pole permanent magnet 13_ThreeForm of
The shape can be changed freely.

As a fourth embodiment of the present invention, as shown in FIG. 8, for example, three permanent magnet pieces 18 ₁ ... Each covered with an insulating layer 19 ₄ . it is also possible to configure the use permanent magnets 13 _4.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0026]

As described above, according to the first aspect of the present invention, the magnetic resistance of each field pole permanent magnet is increased, the eddy current loss is reduced, and the heat generation of the field pole permanent magnet is suppressed. Can be increased. Moreover, depending on the combination of the permanent magnet pieces, the shape of the field pole permanent magnet can be freely changed.

Further, according to the second aspect of the present invention, it is possible to integrate the plurality of permanent magnet pieces and to insulate the permanent magnet pieces from the iron core, and to ensure that the permanent magnet pieces are embedded and held in the iron core.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a permanent magnet type electric motor according to a first embodiment, and is a sectional view taken along line 1-1 of FIG. 2;

FIG. 2 is a front view as viewed in the direction of arrow 2 in FIG.

FIG. 3 is a perspective view of a field pole permanent magnet in a state where an insulating layer is omitted.

FIG. 4 is a temperature characteristic diagram of a field pole permanent magnet.

FIG. 5 is an output characteristic diagram.

FIG. 6 is a perspective view corresponding to FIG. 3 of the field pole permanent magnet of the second embodiment.

FIG. 7 is a perspective view corresponding to FIG. 3 of the field pole permanent magnet of the third embodiment.

FIG. 8 is a perspective view corresponding to FIG. 3 of the field pole permanent magnet of the fourth embodiment.

[Explanation of symbols]

6 ... permanent magnet rotor 12 ... iron core 13 ₁ , 13 ₂ , 13 ₃ , 13 ₄ ... permanent magnets for field poles 18 ₁ , 18 ₂ , 18 ₃ , 18 ₄ ... permanent magnet pieces 19 _1, 19 _2, 19 _3, 19 ₄ ... insulating layer

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Takeo Fukuda 1-4-1 Chuo, Wako-shi, Saitama

Claims (2)

[Claims] A permanent magnet for a field pole (13) is provided at a plurality of circumferentially spaced locations on an outer peripheral portion of an iron core (12) having a circular cross section.
_1, in 13 _2, 13 _3, 13 ₄₎ permanent magnet electric motor type rotor provided with a permanent magnet rotor (6) comprising embedded, permanent magnet field pole _(131-134) is a plurality divided permanent magnet pieces (18 _1, 18 _2, 18 _3,
18 ₄ ) A permanent magnet electric motor, characterized by comprising: 2. The field pole permanent magnets (13 ₁ to 1)
3 ₄₎ a plurality of permanent magnet pieces which constitute the (18 _{1-18 4)}
Whole, each permanent magnet pieces (18 _{1-18 4)} insulating layer while insulating the other (19 _1, 19 _2, 19 _3, 1
9 ₄ permanent magnet type motor according to claim 1, characterized in that it is coated with).