JPH10126986A - Permanent magnet rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet rotor which can improve the performance of a motor by obtaining enough reluctance torque in addition to magnet torque. SOLUTION: This rotor 1 has a rotor core 3 which is constituted by forming holes 8 in the core sheets 2, within the regions A being surrounded by the outer rims of the permanent magnets 4a buried in the stack direction within the slits 5 curved in reverse direction to the peripheral circles of the core sheets 2 made of high permeability material such as an electrical sheets or the like stacked in axial direction of the rotor and the peripheral circles of the core sheets 2, and inserting calking pins 10 made of high permeability material into these holes 8 thereby integrating the stack 7 of the core sheets 2, and besides this is constituted by forming the holes 8, biasing them to the rear side in rotational direction of the core sheets 2. Accordingly, the effective use of the reluctance torque can be made by reducing the influence of the air gap between the hole 8 and the caking pin 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet rotor for a brushless motor having a structure in which permanent magnets are embedded in a rotor core in which core sheets made of a high magnetic permeability material are laminated.

[0002]

2. Description of the Related Art Brushless motors used in refrigerators, air conditioners and the like are particularly required to reduce power consumption. For this reason, a high-efficiency permanent magnet rotor that effectively utilizes reluctance torque in addition to magnet torque is preferable as the rotor of the motor. FIG. 4 is an exploded perspective view showing a configuration of a conventional permanent magnet rotor. FIG. 4 shows a permanent magnet rotor 50 for a four-pole brushless motor, which has a rotor core 52 made of a core sheet 51 made of a high magnetic permeability material such as an electromagnetic steel sheet laminated in the rotor axis direction (vertical direction in the figure). Two permanent magnets 53a, 53b per pole
Are embedded in the laminating direction in a slit 54 curved in the opposite direction to the outer circumferential circle of the core sheet 51 so that the rotor surface is located alternately with the S pole and the N pole. End plates 55a and 55b made of a non-magnetic metal such as brass are provided at both ends of the core sheet 51 in the laminating direction, and the laminated body 56 of the core sheet 51 includes the core sheet 51 and the end plate 55.
a, 55b formed in holes 57, 58a, 58, respectively.
It is fixed at four places by caulking pins 59 made of a high magnetic permeability material penetrating through b.

Conventionally, as shown in FIG. 5, this caulking pin 59 is formed between the outer edge of the outer peripheral permanent magnet 53a and the core sheet 5a.
It was arranged at the center in a region B surrounded by the outer circumference circle of No. 1. When the rotor 50 is set in a stator (not shown), a rotating magnetic field is applied to the rotor core 52 from a plurality of field portions of the stator, thereby generating a magnet torque and a reluctance torque.

[0004]

In the above conventional structure, the caulking pin 59 is provided between the outer edge of the permanent magnet 53a and the core sheet 51.
6A, is located at the center of a magnetic flux path 60 for generating reluctance torque, as shown in FIG. Will be blocked. Even if the caulking pin 59 is made of a magnetic material, an air gap 61 having extremely low magnetic permeability is formed between the hole 57 and the caulking pin 59 as shown in FIG.
Due to the presence of (air), it cannot be denied that the structure is difficult to pass magnetic flux. Therefore, a sufficient reluctance torque cannot be obtained, which is one of the causes of a decrease in motor performance.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional structure, and provides a permanent magnet rotor capable of improving motor performance by obtaining sufficient reluctance torque in addition to magnet torque. It is the purpose.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a permanent magnet embedded in a laminating direction in a slit curved in a direction opposite to an outer circumferential circle of a core sheet made of a high magnetic permeability material laminated in a rotor axial direction. Forming a through hole in the core sheet in a region surrounded by an outer edge of the core sheet and an outer circumferential circle of the core sheet;
By inserting an integrated member made of a high magnetic permeability material into this through hole, in a permanent magnet rotor having a rotor core obtained by integrating the laminated body of the core sheet, the through hole is formed within the region and in the core. It is characterized by being formed so as to be deviated rearward in the rotation direction of the seat.

According to the structure of the present invention, the through hole of the core sheet is formed at a position where the magnetic flux density during rotation of the rotor is lower, thereby preventing the flow of the magnetic flux in the rotor and the integrated member. , The effect of the air gap can be reduced, and the effective use of reluctance torque can be achieved. Thus, by making it easy to pass the magnetic flux formed along the permanent magnet in the rotor, a sufficient reluctance torque is obtained in addition to the magnet torque,
The motor performance can be improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.
Note that the following embodiments are merely examples embodying the present invention, and do not limit the technical scope of the present invention.

The permanent magnet rotor according to the present invention (the present rotor)
The outer edge of a permanent magnet embedded in the lamination direction in a slit curved in the opposite direction to the outer circumference of a core sheet made of a high magnetic permeability material such as an electromagnetic steel sheet laminated in the rotor axis direction and the core sheet By forming a through hole of the core sheet in a region surrounded by an outer peripheral circle and inserting an integrated member made of a high magnetic permeability material into the through hole, the laminated body of the core sheet is integrated. This is the same as the conventional example in that a rotor core is provided. However, this rotor is different from the conventional example in that the through hole is formed so as to be deviated in the region and behind the core sheet in the rotation direction.

Hereinafter, a detailed structure of the rotor will be described. FIG. 1 is an exploded perspective view showing the configuration of the permanent magnet rotor according to the present embodiment. FIG. 1 shows a permanent magnet rotor 1 for a four-pole brushless motor, in which a rotor core 3 made of a core sheet 2 made of a high magnetic permeability material such as an electromagnetic steel sheet laminated in the rotor axis direction (vertical direction in the figure). In addition, two layers of permanent magnets 4a and 4b are provided for each pole,
The core sheet 2 is buried in the laminating direction in the slit 5 curved in the opposite direction to the outer circumferential circle of the core sheet 2 so as to be alternately located with the poles. At both ends of the core sheet 2 in the stacking direction, end plates 6a and 6b made of a nonmagnetic metal such as brass are provided, and the stacked body 7 of the core sheet 2 is provided with holes 8 ( It is fixed at four places by caulking pins 10 (corresponding to an integrated member) made of a high magnetic permeability material penetrating holes 9a, 9b formed in the end plates 6a, 6b. In the present embodiment, the caulking pin 10 is located within the region A surrounded by the outer edge of the outer peripheral permanent magnet 4a and the outer peripheral circle of the core sheet 2 as shown in FIG.
It is arranged at a position deviated to the rear side in the rotation direction.

The reason for this arrangement is as follows. When the rotor 1 is set in a stator (not shown), a rotating magnetic field is applied to the rotor core 3 from a plurality of field portions of the stator, thereby generating reluctance torque. Have analyzed the magnetic flux density distribution during rotation of the rotor 1 by the finite element method in order to clarify the nature of the rotating magnetic field at this time, and the results are shown in FIG. FIG. 3 shows a state where the rotor 1 is rotating counterclockwise (in the direction of the arrow) in the stator 11. Also, the higher the density of the line in the figure, the higher the magnetic flux density (however, the line in the figure does not indicate the flow direction of the magnetic flux). From this figure, it can be seen that on the outer peripheral side of the rotor 1, the magnetic flux density gradually decreases from the front side P1 to the rear side P2 in the rotation direction with respect to the center of the cross section of the permanent magnets 4a, 4b.

Therefore, by forming the hole 8 at the position P2 where the magnetic flux density during rotation is lower as in the above arrangement, the flow of the magnetic flux along the permanent magnet 4a in the rotor 1 is obstructed. Hole 8 and caulking pin 106
And the effect of the air gap between them can be reduced, and sufficient reluctance torque can be generated. That is, according to the configuration of the rotor 1 of the present embodiment, the permanent magnets 4a and 4b having a convex reverse arc shape are used inside the rotor core 3 and a magnetic flux path along the permanent magnet 4a is secured. The motor performance can be improved by increasing the surface area of the magnet, generating a large amount of magnetic flux contributing to the improvement of the magnet torque, and smoothing the flow of the magnetic flux contributing to the improvement of the reluctance torque. However,
Needless to say, the specific position of the hole 8 needs to be a position where there is no interference with the slit 5 of the core sheet 2 in which the permanent magnets 4a and 4b are embedded, and the rotational strength is also considered.

In the above embodiment, the permanent magnet rotor 1 for a four-pole brushless motor has a rotor core 3
Although an example in which two layers of inner and outer permanent magnets 4a and 4b are buried per pole is shown, a multi-pole motor or a rotor core in which one or three or more layers of permanent magnets are buried per pole are used. You may. In the above-described embodiment, the swaging pin 10 is an example of an integrated member. However, the laminate 7 of the core sheet 2 may be fixed by bolts and nuts.
The number of pins may be further increased.

[0014]

As described above, according to the configuration of the present invention, the flow of the magnetic flux in the rotor is obstructed by forming the through hole of the core sheet at a position where the magnetic flux density during rotation of the rotor is lower. The effect of the air gap between the through hole and the integrated member can be reduced, and effective use of the reluctance torque can be achieved. As described above, by easily passing the magnetic flux in the rotor, a sufficient reluctance torque can be obtained in addition to the magnet torque, and the motor performance can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a permanent magnet rotor according to one embodiment of the present invention.

FIG. 2 is a plan view of a core sheet of the permanent magnet rotor.

FIG. 3 is a magnetic flux diagram when the rotor is rotating.

FIG. 4 is an exploded perspective view showing a configuration of a conventional permanent magnet rotor.

FIG. 5 is a plan view of a core sheet of a conventional permanent magnet rotor.

FIG. 6 is an explanatory diagram of functions of a conventional permanent magnet rotor.

[Explanation of symbols]

 Reference Signs List 1 rotor (permanent magnet rotor) 2 core sheet 3 rotor core 4a, 4b permanent magnet 7 laminated body 8 hole (through hole) 10 caulking pin (integrated member)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shizu Yokote 1006 Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. 72) Inventor Hiroshi Ito 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshinari Asano 1006 Odaka Kadoma Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd

Claims (1)

[Claims] 1. An outer edge of a permanent magnet embedded in a lamination direction in a slit curved in a direction opposite to an outer peripheral circle of a core sheet made of a high magnetic permeability material laminated in a rotor axial direction and an outer periphery of the core sheet. In a region surrounded by a circle, a through-hole of the core sheet is formed, and an integrated member made of a high-permeability material is inserted into the through-hole to integrate the core sheet laminate. A permanent magnet rotor comprising a rotor core comprising: a through-hole that is formed so as to be deviated in the region and rearward in the rotation direction of the core sheet.