JPH10174326A - Permanent magnet-buried rotor for motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet-buried rotor for motors where permanent magnets in one or more layers per pole are buried in the opening of a cylindrical rotor core, and a method for the manufacture of the rotor wherein efficiency is not degraded even if a means for securing the permanent magnets is installed. SOLUTION: The rotor for motors is a permanent magnet-buried rotor for motors wherein permanent magnet 2, 3 are buried in a cylindrical rotor core 1 composed of a material with a high permeability. In the peripheral portion of the rotor core 1 close to the end face of the permanent magnets 2, 3 in the direction of thrust, the size of the peripheral bridge sections 4, 5 that are opposite to both the ends of the circular arcshaped cross section of the permanent magnet 2, 3 and thin, are reduced to a value smaller than the outside diameter of the rotor core 1 and brought into tight contact with the permanent magnets 2, 3. Thereby the permanent magnets 2, 3 are secured to the rotor core 1 so that efficiency will not result even if a means for securing the permanent magnets to the rotor core is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet embedded motor rotor and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, one or more permanent magnets per pole are buried in the cylindrical axis direction on the outer peripheral portion of a cylindrical rotor core utilizing the torque generated by permanent magnets, and the cross section is arc-shaped and arc-shaped. 2. Description of the Related Art There is known an electric motor rotor of a permanent magnet embedded type in which a convex portion faces the outer periphery of a rotor core. In a permanent magnet embedded motor rotor, a permanent magnet having a smaller cross-sectional area than the opening of the rotor core is often inserted. This is because when a permanent magnet having a larger cross-sectional area than the opening of the rotor core is inserted into the opening of the rotor core, the insertion pressure causes the permanent magnet to rub against the rotor core and produce shavings. This is because the applied stress may lead to deformation or breakage of the rotor core. However, when a permanent magnet having a smaller cross-sectional area than the opening of the rotor core is inserted, a gap is formed between the rotor core and the permanent magnet. At the time of rotation, the permanent magnet swings and generates vibrations and sounds, or in the worst case, the permanent magnet is damaged. For this reason, a permanent magnet embedded type electric motor in which an engagement protrusion for pressing and fixing a permanent magnet is provided in a permanent magnet insertion opening of a cylindrical rotor core as disclosed in Japanese Patent Application Laid-Open No. Hei 6-133479. Rotors are known.

FIG. 6 shows a conventional rotor core in which permanent magnets are fixed by engaging projections. The permanent magnet 61 inserted into the rotor core 60 presses and deforms the engaging projection 63 of the rotor core 60 in the M direction in the drawing on the chamfered surface 62 of the permanent magnet, and the elasticity of the engaging projection 63 in the P direction is restored. The permanent magnet 61 is fixed to the rotor core 60 by force. Further, in order to avoid the rotor outer peripheral ring portion 64 and the rotor yoke portion 65, which are the passages of the magnetic flux of the permanent magnet 61, as much as possible, the engaging projection 63 is inserted into the permanent magnet 61 away from the central portion of the permanent magnet 61 with a relatively low magnetic flux density. It is provided at the corner of the opening for use. However, since the permanent magnet 61 is provided with the chamfered surface 62, the absolute amount of the permanent magnet 61 is reduced and the amount of magnetic flux generated by the permanent magnet 61 is reduced.
Of the magnetic flux near the chamfered surface 62 of the permanent magnet 61
Is reduced, and the efficiency of the permanent magnet embedded motor rotor is slightly reduced.

However, due to the recent demand for energy saving, higher efficiency is required.
A permanent-magnet embedded motor rotor having a rotor that positively uses reluctance torque in addition to the use of torque generated by a conventional permanent magnet as described in Japanese Patent No. 134023 has been developed. FIG. 7 shows the rotor. The reluctance torque can be effectively used by transmitting the magnetic flux generated by the stator winding through the rotor yoke B section 67 as a passage between the AB and the low loss. On the other hand, the magnetic flux generated by the permanent magnets 68 and 69 is generated by the rotor yoke A 70, the rotor yoke B 67,
Since it is transmitted with low loss between the CDs of the rotor yoke C portion 71,
The torque generated by the permanent magnets 68 and 69 can be effectively used. With this configuration, the torque of the permanent magnet embedded motor is the sum of the reluctance torque and the torque generated by the permanent magnet. Can be generated, and the efficiency of the electric motor can be increased. At this time, if engaging projections 73 and 74 are provided on the rotor core 72 as shown in FIG. 8 to fix the permanent magnet by a conventional method, the chamfered surfaces 77 and 78 are provided on the permanent magnets 75 and 76 over a wide range, respectively. Since it is necessary to reduce the absolute amount of the permanent magnet, the amount of magnetic flux is reduced, and the passage of the magnetic flux near the chamfered surfaces 77, 78
As a result, the torque generated by the permanent magnets 75 and 76 decreases, and the efficiency of the permanent magnet embedded motor rotor decreases due to the provision of the permanent magnet fixing means. .

[0005]

In the above-mentioned conventional permanent magnet fixing means, it is necessary to provide an engaging projection for engaging the permanent magnet on the rotor core and to provide a chamfered surface for engaging the engaging projection on the permanent magnet. However, the present invention solves the problem that the torque generated by the permanent magnet is reduced and the efficiency is reduced.However, even if a means for fixing the permanent magnet is provided, the efficiency is not reduced. An object of the present invention is to provide a motor rotor having a magnet embedded type and a method of manufacturing the same.

[0006]

Means for Solving the Problems To achieve the above object, a first invention of the present invention is to provide a cylindrical rotor core made of a material having a high magnetic permeability with one or more permanent magnets per pole in a cylindrical axial direction. Embedded in the permanent magnet is a permanent magnet embedded motor rotor having a configuration in which the cross section of the permanent magnet is arc-shaped, and the arc-shaped curved convex portion of the permanent magnet faces the rotation center of the rotor core. In the outer peripheral portion of the rotor core adjacent to the end face in the thrust direction of the permanent magnet, a thin outer peripheral bridge portion facing both ends of the arc-shaped cross section of the permanent magnet is set to be smaller than the outer diameter of the rotor core. The permanent magnet is fixed to the rotor core by reducing the size of the permanent magnet and making the structure close to the permanent magnet.

According to this configuration, it is not necessary to provide a means for fixing the permanent magnet to the rotor core at a position where the passage of the magnetic flux of the reluctance torque or the torque generated by the permanent magnet is obstructed. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke with low loss, and can be effectively used without lowering the reluctance torque.The magnetic flux generated by the permanent magnet can also be transmitted through the rotor yoke with low loss. Since it can be transmitted, the torque generated by the permanent magnet can also be used effectively. Furthermore, since it is not necessary to chamfer the permanent magnet in a wide range in order to lock it to the engaging projection as in the related art, the absolute amount of the permanent magnet is not reduced, and the amount of magnetic flux generated by the permanent magnet is not reduced. . As a result, it is possible to provide a permanent magnet embedded motor rotor in which the efficiency does not decrease even if the permanent magnet is fixed to the rotor core.

According to a second invention of the present invention, one or more permanent magnets are buried in a cylindrical axial direction per pole in a cylindrical rotor core made of a material having a high magnetic permeability, and the permanent magnet has a circular arc cross section. A permanent magnet embedded motor rotor having a configuration in which the arc-shaped curved convex portion of the permanent magnet faces the center of rotation of the rotor core, wherein a corner portion of the end surface of the permanent magnet in the thrust direction is provided. The outer peripheral bridge of the rotor core adjacent to the chamfered corner of the permanent magnet is thinned to face both ends of the arc-shaped cross section of the permanent magnet. The permanent magnet is fixed to the rotor core by closely adhering to the chamfered corners.

According to this configuration, since the chamfered corner of the permanent magnet is pressed by the outer peripheral bridge,
There is an advantage that the permanent magnet can be more strongly pressed and fixed in the thrust direction of the rotor core as compared with the first invention. Thus, there is no need to provide a means for fixing the permanent magnet to the rotor core at a position where the path of the magnetic flux of the reluctance torque or the torque generated by the permanent magnet is obstructed. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke with low loss, and can be effectively used without lowering the reluctance torque.The magnetic flux generated by the permanent magnet can also be transmitted through the rotor yoke with low loss. Since the torque can be transmitted, the torque generated by the permanent magnet can be effectively used, and therefore, a permanent magnet embedded motor rotor can be provided which does not reduce the efficiency even when the permanent magnet is fixed to the rotor core.

According to a third aspect of the present invention, there is provided a cylindrical rotor core made of a high magnetic permeability material having one or more openings per pole in a cylindrical axial direction, and the opening has an arc-shaped cross section. In the opening of the rotor core having a configuration in which the arc-shaped curved convex portion of the opening faces the rotation center of the rotor core, a cross section having a cross-sectional area smaller than the cross-sectional area of the opening is provided. A step of inserting an arc-shaped permanent magnet, and a thin outer peripheral bridge that is opposed to both ends of the arc-shaped cross section of the permanent magnet at an outer peripheral portion of the rotor core adjacent to an end face in a thrust direction of the permanent magnet. And pressing the permanent magnet by deforming the portion in the radial direction of the rotor core by pressing means, and fixing the permanent magnet to the rotor core.

According to this manufacturing method, it is not necessary to provide a means for fixing the permanent magnet to the rotor core at a position where the passage of the magnetic flux of the reluctance torque or the torque generated by the permanent magnet is obstructed. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke with low loss.
It is possible to effectively utilize the reluctance torque without lowering it, and the magnetic flux generated by the permanent magnet can also be transmitted through the rotor yoke with low loss. It is possible to provide a method for manufacturing a permanent magnet embedded type motor rotor that does not reduce the efficiency even when the magnet is fixed to the rotor core.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first invention, one or more permanent magnets per pole are buried in a cylindrical axial direction in a cylindrical rotor core made of a material having a high magnetic permeability as in the first aspect of the present invention. The permanent magnet has an arc-shaped cross section, and the arc-shaped curved convex portion of the permanent magnet is directed to a rotation center of the rotor core. At the outer peripheral portion of the rotor core close to the end face in the thrust direction of the permanent magnet, a thin outer peripheral bridge portion facing both ends of the arc-shaped cross section of the permanent magnet is smaller than the outer diameter of the rotor core. Then, the permanent magnet can be fixed to the rotor core by being in close contact with the permanent magnet.

Thus, the permanent magnet can be fixed without reducing the absolute amount of the permanent magnet and without obstructing the passage of the magnetic flux, so that the reluctance torque and the torque generated by the permanent magnet are not reduced, and the permanent magnet can be fixed. It is possible to provide a permanent magnet embedded motor rotor in which the efficiency does not decrease even if the magnet is fixed to the rotor core.

According to a second aspect of the present invention, as in the second aspect of the invention, one or more permanent magnets per pole are buried in a cylindrical axial direction in a cylindrical rotor core made of a high magnetic permeability material, The permanent magnet is a permanent-magnet embedded motor rotor having a configuration in which a cross section has an arc shape, and an arc-shaped curved convex portion of the permanent magnet faces a rotation center of the rotor core. The corners of the end faces in the thrust direction of the permanent magnet are chamfered, and the outer peripheral portion of the rotor core adjacent to the chamfered corners of the permanent magnet has a thin wall facing both ends of the arc-shaped cross section of the permanent magnet. The permanent magnet can be fixed to the rotor core by closely attaching the outer peripheral bridge portion to the chamfered corner of the permanent magnet.

According to this configuration, since the chamfered corner of the permanent magnet is pressed by the outer peripheral bridge,
There is an advantage that the permanent magnet can be more strongly pressed and fixed in the thrust direction of the rotor core as compared with the first invention. As a result, the permanent magnet can be fixed without substantially reducing the absolute amount of the permanent magnet and without obstructing the path of the magnetic flux, so that the reluctance torque and the torque generated by the permanent magnet are not reduced. It is possible to provide a permanent magnet embedded motor rotor in which the efficiency does not decrease even when the motor rotor is fixed to the rotor core.

According to a third aspect of the present invention, there is provided a cylindrical rotor core made of a high magnetic permeability material having one or more openings per pole in a cylindrical axial direction, as in the third aspect of the present invention.
The opening has an arc-shaped cross-section, and the arc-shaped curved convex portion of the opening faces the center of rotation of the rotor core. A step of inserting an arc-shaped permanent magnet having a cross-sectional area smaller than that of the permanent magnet, and at both ends of the arc-shaped cross section of the permanent magnet at an outer peripheral portion of the rotor core close to an end face in a thrust direction of the permanent magnet. Fixing the permanent magnet to the rotor core by deforming the opposed thin peripheral bridge portion in the radial direction of the rotor core by pressing means to press the permanent magnet. be able to.

According to this method, the permanent magnet can be fixed without reducing the absolute amount of the permanent magnet and without obstructing the path of the magnetic flux, so that the reluctance torque and the torque generated by the permanent magnet can be reduced. It is possible to provide a method of manufacturing a motor rotor having a permanent magnet embedded type in which the efficiency does not decrease even if the permanent magnet is fixed to the rotor core.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) In FIG. 1, reference numeral 1 denotes a rotor core, which fixes the permanent magnets 2 and 3 to the rotor core 1.
This is realized by making the outer peripheral bridge portion 4 of the rotor core smaller than the outer diameter of the rotor core 1 and closely contacting the permanent magnets 2 and 3. A permanent magnet embedded motor rotor comprising permanent magnets 2 and 3 embedded in a cylindrical rotor core 1 made of a high magnetic permeability material, wherein the rotor core 1 is close to the end faces of the permanent magnets 2 and 3 in the thrust direction. Of the outer periphery of
The outer peripheral bridge portions 4 and 5 of the rotor core 1 facing the both ends of the arc-shaped cross section of the permanent magnets 2 and 3 are made smaller than the outer diameter of the rotor core 1 to be in close contact with the permanent magnets 2 and 3. With this configuration, the permanent magnets 2 and 3 are fixed to the rotor core 1. FIG. 2 is a part of a sectional view taken along the line YZ of FIG. 1. The outer peripheral bridge portion 4 is made smaller than the outer diameter of the rotor core 1, and the permanent magnet 2 is pressed and fixed by the stress in the R direction on the inner diameter side of the rotor core 1. And is pressed and fixed by the stress in the thrust direction S. The range in which the outer peripheral bridge portion 4 is smaller than the outer diameter of the rotor core 1 is limited to the range of the outer peripheral bridge portions 4 and 5 of the rotor core if the holding force for fixing the permanent magnets 2 and 3 to the rotor core 1 is obtained. Rotor core 1
May be all or part of the cylindrical axis direction. Further, the means for making the outer peripheral bridge portions 4 and 5 of the rotor core smaller than the outer diameter of the rotor core 1 are as follows.
After the insertion, the outer peripheral bridge portions 4 and 5 of the rotor core may be pressed and deformed. Alternatively, the outer peripheral bridge portions 4 and 5 of the rotor core may be permanently fixed to the rotor core 1 in which the outer diameter is smaller than the outer diameter of the rotor core 1. The magnets 2 and 3 may be inserted. According to this configuration, as shown in FIG. 1, rotor yoke B section 7 which is a path of magnetic flux of reluctance torque and rotor yokes A section 6, B which are a path of magnetic flux of torque generated by permanent magnets
There is no need to provide an engaging projection for fixing the permanent magnet to the rotor core in the portions 7 and 8. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke B section 7 with low loss, and can be effectively used without lowering the reluctance torque. , B part 7 and C part 8 can be transmitted with low loss.
It is structured so that the torque generated can be used effectively. Further, since it is not necessary to chamfer the permanent magnets 2, 3, it is not necessary to reduce the absolute amount of the permanent magnets 2, 3, and the amount of magnetic flux generated by the permanent magnets 2, 3 does not decrease. Thereby, even if the permanent magnets 2 and 3 are fixed to the rotor core 1, the permanent magnet embedded motor rotor whose efficiency does not decrease can be provided. Although the rotor core 1 is a laminated core in FIG. 2, a similar effect can be obtained with an integral core.

(Embodiment 2) FIG. 3 shows a permanent magnet embedded motor rotor in which permanent magnets 12, 13 are embedded in a cylindrical rotor core 11 made of a high magnetic permeability material. Of the permanent magnet has chamfered corners 14 and 15, and the chamfered corner 1 of the permanent magnet.
Outer peripheral bridge portions 16 and 17 of rotor core 11 which are opposed to both ends of the arc-shaped cross section of permanent magnets 12 and 13 at the outer peripheral portion of rotor core 11 close to 4 and 15.
Are in close contact with the chamfered corners 14 and 15 of the permanent magnet, so that the permanent magnets 12 and 13 are fixed to the rotor core 11. FIG. 4 is a part of the WX sectional view of FIG. 3, in which the outer peripheral bridge portion 16 is made smaller than the outer diameter of the rotor core 11, and the permanent magnet 12 is disassembled in the inner diameter side T2 direction and the thrust direction T3 of the rotor core 11. It is pressed and fixed by the stress in the direction of T1 as possible. According to this configuration, since the chamfered corners 14 and 15 of the permanent magnet are pressed by the outer circumferential bridges 16 and 17, the permanent magnets 12 and 13 can be connected to the thrust of the rotor core 11 in comparison with the first invention. There is an advantage that it can be more securely pressed and fixed in the direction.
The range in which the outer peripheral bridge portion 16 is smaller than the outer diameter of the rotor core 11 is defined by the outer peripheral bridge portion 1 of the rotor core.
It may be carried out over all or a part of the 6, 17 rotor cores 11 in the cylindrical axis direction. Further, the means for making the outer peripheral bridge portions 16 and 17 of the rotor core smaller than the outer diameter of the rotor core 11 are provided by the permanent magnets 12 and 17.
13 after insertion, the outer circumferential bridge portions 16 and 17 of the rotor core
May be pressed or deformed, or the permanent magnets 12 and 13 may be inserted into the rotor core 11 in which the outer peripheral bridge portions 16 and 17 of the rotor core are smaller than the outer diameter of the rotor core 11 in advance. According to this configuration, the rotor yoke B portion 19, which is a passage for the magnetic flux of the reluctance torque, and the rotor yoke A portion 1, which is a passage for the magnetic flux of the torque generated by the permanent magnet.
It is not necessary to provide engaging projections for fixing the permanent magnet to the rotor core in the 8, B portion 19 and C portion 20. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke B section 19 with low loss, and can be effectively used without reducing the reluctance torque.
Since it can be transmitted through the 8, B portion 19 and C portion 20 with low loss, the structure is such that the torque generated by the permanent magnets 12 and 13 can be effectively used. Further, the permanent magnets 12, 1
Since the chamfer 3 is only required at a part of the corner in the thrust direction, it is not necessary to chamfer the permanent magnet in a wide range unlike the case where the permanent magnet is fixed by the engaging projection. Therefore, the absolute amount of the permanent magnets 12 and 13 hardly decreases, so that the permanent magnets 12 and 13
Does not decrease. Thus, it is possible to provide a permanent magnet embedded motor rotor whose efficiency does not decrease even if the permanent magnets 12 and 13 are fixed to the rotor core 11.
Although the rotor core 11 is a laminated core in FIG. 4, the same effect can be obtained with an integral core.

(Embodiment 3) FIG. 5 illustrates a manufacturing method for fixing a permanent magnet 21 to a cylindrical rotor core. In FIG. 5, a permanent magnet 23 having a cross-sectional area smaller than the cross-sectional area of the opening 22 is inserted into an opening 22 of a rotor core 21 made of a high magnetic permeability material. Fixed to. Next, the pressing body 24 as the pressing means is moved, and the thin portion of the rotor core 21 facing both ends of the arc-shaped cross section of the permanent magnet 23 on the outer peripheral portion of the rotor core 21 close to the end face of the permanent magnet 23 in the thrust direction. The outer peripheral bridge portion 25 is pressed by the pressing body 24 and deformed in the inner diameter direction. The permanent magnet 23 is fixed to the rotor core 21 by pressing the corners of the permanent magnet 23 with the deformed outer peripheral bridge portion 25. The material of the pressing body 24 is formed of a metal, a resin, or the like having hardness enough to withstand a reaction caused by deformation of the outer peripheral bridge portion 25 of the rotor core. The moving amount of the pressing body 24 is
May be fixed to the rotor core 21 by deformation of the outer peripheral bridge portion 25 of the rotor core, or may be all over the rotor core 21 in the cylindrical axial direction. Thereby, the permanent magnet 23 can be fixed to the rotor core 21, and a permanent magnet embedded motor rotor whose efficiency is not reduced by the means for fixing the permanent magnet 23 can be provided. The pressing and fixing means shown in FIG.
Although the pressing and fixing method by moving the pressing body 24 in the direction parallel to the cylindrical axis direction 1 has been described, the pressing and fixing method by moving the pressing body 24 in the direction perpendicular to or oblique to the cylindrical axis direction of the rotor core 21 may be used. . Although the rotor core 21 is a laminated core in FIG. 5, the same effect can be obtained with an integral core.

[0022]

As is clear from the above description, the present invention
The following effects can be obtained as compared with the conventional example.

According to a first aspect of the present invention, one or more permanent magnets per pole are buried in a cylindrical rotor core made of a high magnetic permeability material in a cylindrical axial direction, and the permanent magnets have an arc-shaped cross section. An electric motor rotor of a permanent magnet embedded type in which an arc-shaped curved convex portion of the permanent magnet faces a rotation center of the rotor core, wherein an outer periphery of the rotor core is close to an end face of the permanent magnet in a thrust direction. In the portion, the outer peripheral bridge portion, which is a thin wall opposed to both ends of the arc-shaped cross section of the permanent magnet, is smaller than the outer diameter of the rotor core, and is brought into close contact with the permanent magnet. It is fixed to the rotor core. According to this configuration, it is not necessary to provide an engagement projection for fixing the permanent magnet at a position where the path of the magnetic flux of the reluctance torque or the torque generated by the permanent magnet is obstructed unlike the conventional example. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke with low loss, and can be effectively used without lowering the reluctance torque.The magnetic flux generated by the permanent magnet can also be transmitted through the rotor yoke with low loss. Since the torque can be transmitted, the torque generated by the permanent magnet can be effectively used. Furthermore, since it is not necessary to chamfer the permanent magnet widely, there is no need to reduce the absolute amount of the permanent magnet, and the amount of magnetic flux generated by the permanent magnet does not decrease. As a result, it is possible to provide a permanent magnet embedded motor rotor in which the efficiency does not decrease even if the permanent magnet is fixed to the rotor core.

According to a second aspect of the present invention, one or more permanent magnets per pole are buried in a cylindrical axial direction in a cylindrical rotor core made of a material having a high magnetic permeability, and the permanent magnets have an arc-shaped cross section. An electric motor rotor of a permanent magnet embedded type in which the arc-shaped curved convex portion of the permanent magnet faces the rotation center of the rotor core, wherein a corner of a thrust direction end face of the permanent magnet is chamfered, At the outer peripheral portion of the rotor core adjacent to the chamfered corner portion of the permanent magnet, a thin peripheral bridge portion facing both ends of the arc-shaped cross section of the permanent magnet is formed with the chamfered corner of the permanent magnet. The permanent magnet is fixed to the rotor core by being in close contact with the rotor core. According to this configuration, since the chamfered corners of the permanent magnet are pressed by the outer peripheral bridge, the permanent magnet is pressed more strongly in the thrust direction of the rotor core than in the first invention. There is an advantage that can be fixed. Accordingly, it is not necessary to provide an engagement projection for fixing the permanent magnet at a position where the passage of the magnetic flux of the reluctance torque or the torque generated by the permanent magnet is obstructed unlike the conventional example. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke with low loss, and can be effectively used without lowering the reluctance torque.The magnetic flux generated by the permanent magnet can also be transmitted through the rotor yoke with low loss. Because it can be transmitted
The torque generated by the permanent magnet can be used effectively. As a result, it is possible to provide a permanent magnet embedded motor rotor in which the efficiency does not decrease even if the permanent magnet is fixed to the rotor core.

According to a third aspect of the present invention, there is provided a cylindrical rotor core made of a material having a high magnetic permeability, having one or more openings in a cylindrical axial direction per pole, wherein the openings have an arc-shaped cross section.
In the opening of the rotor core, in which the arc-shaped curved convex portion of the opening faces the center of rotation of the rotor core, the cross section having a cross-sectional area smaller than the cross-sectional area of the opening is an arc-shaped permanent. A step of inserting a magnet, and pressing an outer peripheral bridge portion, which is a thin wall facing both ends of an arc-shaped cross section of the permanent magnet, at an outer peripheral portion of the rotor core close to an end face in a thrust direction of the permanent magnet. And pressing the permanent magnet by deforming the permanent magnet in the inner diameter direction of the rotor core by the means, whereby the permanent magnet can be fixed to the rotor core. According to this manufacturing method, there is no need to provide an engaging projection for fixing the permanent magnet at a position that obstructs the passage of the magnetic flux of the reluctance torque or the torque generated by the permanent magnet as in the conventional example. Therefore, the magnetic flux generated by the stator winding can be transmitted through the rotor yoke with low loss, and can be effectively used without lowering the reluctance torque.The magnetic flux generated by the permanent magnet can also be transmitted through the rotor yoke with low loss. Since the torque can be transmitted, a structure that can effectively use the torque generated by the permanent magnet can be realized. Accordingly, it is possible to provide a method of manufacturing a permanent magnet embedded motor rotor in which the efficiency does not decrease even if the permanent magnet is fixed to the rotor core.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a motor rotor with embedded permanent magnets according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a part of the YZ section shown in FIG. 1;

FIG. 3 is a partial plan view of a permanent magnet embedded motor rotor according to a second embodiment of the present invention;

FIG. 4 is a sectional view of a part of a WX part shown in FIG. 3;

FIG. 5 is a cross-sectional view illustrating a main part of a method for manufacturing a permanent magnet embedded motor rotor according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a part of a conventional permanent magnet embedded type motor rotor.

FIG. 7 is a partial plan view of a conventional permanent magnet embedded motor rotor that also utilizes reluctance torque.

FIG. 8 is a partial cross-sectional view of the permanent magnet embedded motor rotor shown in FIG. 7;

[Explanation of symbols]

 1,11,21 Rotor core 2,3,12,13,23 Permanent magnet 4,5,16,17 Peripheral bridge 6,18 Rotor yoke A 7,19 Rotor yoke B 8,20 Rotor yoke C 14,14 Part 24 pressing body (pressing means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Murakami 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Kazunari Narasaki 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A single-layer or multi-layer permanent magnet per pole is buried in a cylindrical axial direction in a cylindrical rotor core made of a material having a high magnetic permeability, and the permanent magnet has an arc-shaped cross section. A permanent magnet embedded type motor rotor having a configuration in which an arc-shaped curved convex portion faces the rotation center of the rotor core, wherein an outer peripheral portion of the rotor core near an end face of the permanent magnet in a thrust direction, The outer peripheral bridge portion, which is thinner in opposition to both ends of the arc-shaped cross section of the permanent magnet, is made smaller than the outer diameter of the rotor core and is closely attached to the permanent magnet, so that the permanent magnet is attached to the rotor core. A permanent magnet embedded motor rotor characterized by being fixed. 2. A one-pole or multi-layer permanent magnet per pole is buried in a cylindrical axial direction in a cylindrical rotor core made of a high magnetic permeability material, wherein said permanent magnet has an arc-shaped cross section. A permanent magnet embedded type motor rotor having a configuration in which an arc-shaped curved convex portion faces a rotation center of the rotor core, wherein a corner of a thrust direction end face of the permanent magnet is chamfered, and the chamfer of the permanent magnet is chamfered. At the outer peripheral portion of the rotor core adjacent to the formed corner portion, the outer peripheral bridge portion, which is opposed to both ends of the arc-shaped cross section of the permanent magnet and is thin, is closely attached to the chamfered corner portion of the permanent magnet. The permanent magnet is fixed to the rotor core by doing so, wherein the permanent magnet embedded motor rotor is provided. 3. A cylindrical rotor core made of a high magnetic permeability material has one or more openings per cylinder in the axial direction of the cylinder.
The opening has an arc-shaped cross-section, and the arc-shaped curved convex portion of the opening faces the center of rotation of the rotor core. A step of inserting an arc-shaped permanent magnet having a cross-sectional area smaller than that of the permanent magnet, and at both ends of the arc-shaped cross section of the permanent magnet at an outer peripheral portion of the rotor core close to an end face in a thrust direction of the permanent magnet. Pressing the permanent magnet by deforming the opposed outer peripheral bridge portion of the rotor core in the inner diameter direction of the rotor core by pressing means, and fixing the permanent magnet to the rotor core. A method for manufacturing a permanent magnet embedded motor rotor.