JP2001086675A - Self-starting permanent magnet synchronous motor, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the process of cutting the outside periphery of a rotor iron core by preventing the shrinkage distortion of the outside periphery of the rotor iron core after die-casting of the rotor of a self-starting permanent magnet type of synchronous motor. SOLUTION: In addition to a section where the width of the bridge part A7 between the adjacent permanent magnet burying holes 6 of a rotor iron core 2 is large, this rotor iron core 2 is provided with a wide section so as to raise the strength of the bridge part, thereby removing the distortion of the outside periphery of the rotor iron core 2 after aluminum die-casting. This dispenses with the process of cutting the outside periphery of the rotor iron core, by forming the rotor iron core where electromagnetic steel plates are die-cut in advance and are stacked so that the air gap between it and the inside periphery of the stator iron core may come to specified dimensions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-starting permanent magnet type synchronous motor for use in electric compressors for refrigeration equipment and air conditioning equipment and for general industries.

[0002]

2. Description of the Related Art A self-starting type permanent magnet type synchronous motor operates as an induction motor by a squirrel-cage conductor for starting a rotor at the time of starting, and when the rotor reaches near a synchronous speed, a rotor magnetic pole by the permanent magnet turns the rotor winding. It performs synchronous operation by being drawn into a rotating magnetic field that rotates at a synchronous speed created by a line, but has excellent performance such as constant speed operation and high efficiency.
In particular, various improvements have been made to the rotor structure of the electric motor.

An example of a conventional self-starting type permanent magnet synchronous motor rotor is disclosed in Japanese Patent Application Laid-Open No. 9-308195. Hereinafter, the rotor of the conventional self-starting permanent magnet type synchronous motor will be described with reference to FIGS.

FIG. 8 is a radial sectional view of the rotor, and FIG.
FIG. 3 is an axial cross-sectional view of the rotor. FIG. 10 shows A in FIG.
It is the elements on larger scale of a part. 8 to 10, reference numeral 1 denotes a rotor, and 2 denotes a rotor core made of laminated electromagnetic steel sheets.
Reference numeral 3 denotes a conductor bar, which is integrally formed with the short-circuit rings 4 located at both ends of the rotor core 2 by aluminum die casting to form a starting cage conductor. Reference numeral 5 denotes a permanent magnet, and two permanent magnets 5 of the same polarity are fitted into a permanent magnet burying hole 6 provided in the axial direction of the rotor core 2 in a mountain shape with the bridge portion 7 of the rotor core 2 interposed therebetween. One rotor magnetic pole is made by arranging them in such a manner that the rotor as a whole forms four rotor magnetic poles.

Further, two adjacent permanent magnets 5 of different polarities are provided.
Are directly abutted on each other in a mountain shape, and a bridge portion of a rotor core is not provided between both permanent magnets 5.

Reference numeral 8 denotes a nonmagnetic end plate for protecting a permanent magnet. Reference numeral 9 denotes a shaft hole of the rotor 1, and reference numeral 10 denotes a shaft mounted on the rotor 1.

Further, the conventional manufacturing method uses the rotor core 2
After the permanent magnet 5 is inserted into the rotor core and the end plate is brought into contact with the rotor core, a starting cage conductor is formed by aluminum die casting, and the end plate is simultaneously integrally formed with the rotor core 2.
Manufacturing method.

[0008]

However, in the above-mentioned conventional construction, the bridge portion 7 between the permanent magnets 5 having the same polarity comes into contact with the butted end face of the permanent magnet 5 as shown in the portion A of FIG. Or only small gaps are provided. As a result, as shown in FIG. 10, the number of magnetic flux short circuits between different poles in the end face 5a of the permanent magnet 5 increases, and the strength of the rotor magnetic pole by the permanent magnet 5 decreases. Therefore, the motor has a problem that the step-out torque is reduced and the current is increased to deteriorate the performance of the motor.

Further, no bridge portion of the rotor core 2 is provided between two adjacent permanent magnets 5 of different polarities.
The outer portion and the inner portion of the permanent magnet burying hole 6 of the rotor core 2 are connected only by the bridge portion 7, and there is a disadvantage that the strength is weak.

Further, after the starting cage conductor is formed by aluminum die casting, when the shorting ring 4 cools and contracts inward,
Both ends in the axial direction of the rotor core 2 also contract inward due to the stress. At this time, since no bridge portion is provided near the abutting portion of the two permanent magnets 5 having different polarities, the width of the permanent magnet burying hole 6 in the radial direction is reduced, and the gap between the permanent magnet 5 inserted before the aluminum die casting is formed. Disappears,
The outer diameter of the rotor core is reduced.

On the other hand, the permanent magnet burying hole 6 near the bridge 7
Of the rotor core 2 does not substantially change because the bridge portion 7 supports the contraction stress even by aluminum die casting, and the outer diameter of the rotor core 2 does not change. Thus, the rotor core 2
The outer diameter of the rotor core differs depending on the location. Therefore, even if it is attempted to form the gap dimension with the stator core inner diameter only by punching out the electromagnetic steel plate of the rotor core 2, it cannot be accurately obtained. There is a problem that the outer diameter of the rotor core 2 needs to be cut and the man-hour is increased.

Further, a permanent magnet 5 is inserted into the rotor core 2,
Moreover, since the aluminum die casting is performed after the end plate 8 is brought into contact with the rotor core 2, there is a problem that the aluminum die casting operation is complicated and defective products are easily generated.

The present invention has been made in consideration of the above problems, and has been made in consideration of the above problem.
A high-performance and inexpensive self-starting permanent magnet synchronous motor with a highly productive manufacturing method that prevents magnetic flux short-circuiting inside the rotor, eliminates the need to cut the outer diameter of the rotor core 2, and facilitates aluminum die-casting work. The purpose is to provide.

[0014]

In order to achieve the above object, the present invention provides a permanent magnet having the same polarity with a mountain-like shape sandwiching a radial bridge portion having a narrow portion and a wide portion of a rotor core. And a space for preventing a magnetic flux short circuit between the end face of the permanent magnet and the bridge section, so as to prevent a magnetic flux short circuit between different poles in the end face of the permanent magnet. The performance of the motor can be improved, and the shrinkage strain at the center of the rotor magnetic pole of the outer diameter of the rotor core due to radial shrinkage of the short-circuit ring after aluminum die-casting is reduced due to the increased strength of the bridge portion. Since the gap between the inner diameter of the stator core and the inner diameter of the stator core can be accurately determined only by punching out the electromagnetic steel plate of the rotor core, it is not necessary to cut the outer diameter of the rotor core. Low man-hours It can be.

Further, in the present invention, the permanent magnets of the same polarity are arranged so as to sandwich the two bridges provided on the rotor core, so that the outer diameter of the rotor core near the center of the rotor magnetic pole of the rotor core after aluminum die-casting. Is further reduced, and the gap size with the inner diameter of the stator core can be determined more accurately.

The present invention also provides a two-pole permanent magnet rotor in which a radial gap between the permanent magnet burying hole and the permanent magnet is formed so as to gradually increase from the end of the rotor magnetic pole toward the center. Since the starting cage-shaped conductor is formed by aluminum die casting on the iron core and the permanent magnet is mounted, the shrinkage strain in the radial direction of the outer diameter of the rotor core after aluminum die casting is the center of the rotor magnetic pole. Even if it becomes larger toward the vicinity, a sufficient gap between the permanent magnet and the permanent magnet can be secured, and the permanent magnet can be easily inserted into the permanent magnet burying hole without any trouble. Aluminum die casting is performed without permanent magnets or end plates, so the work is simplified.

Further, according to the present invention, in a two-pole permanent magnet rotor, the outer diameter of the rotor core is formed in an elliptical shape such that the outer diameter gradually increases from the end to the center of the rotor magnetic pole. After the starting cage-shaped conductor is formed by aluminum die-casting, the manufacturing method is to mount a permanent magnet, so that the radial shrinkage strain of the outer diameter of the rotor core after aluminum die-casting approaches the center of the rotor magnetic pole. Even if it becomes larger, the outer diameter of the rotor core after shrinkage can be made almost a perfect circle, so the gap size between the inner diameter of the stator core and the inner diameter of the stator core can be accurately determined only by punching out the electromagnetic steel sheet of the rotor core. This eliminates the need for external diameter cutting of the rotor core, thereby reducing man-hours. In addition, since aluminum die casting is performed without a permanent magnet or end plate, the operation is simple, defective products are less likely to appear, and productivity can be increased.

Further, in the present invention, since the permanent magnet is formed of a rare earth magnet, a strong magnetic force is obtained, so that the entire rotor and electric motor can be reduced in size and weight.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention is directed to a stator in which a winding is wound around a stator core, and freely rotates facing a cylindrical inner diameter surface of the stator core, A plurality of conductor bars located near the outer periphery of the rotor core and short-circuit rings located at both axial end surfaces of the rotor core are integrally formed by aluminum die casting to form a starting cage conductor, and A motor comprising a rotor in which a plurality of permanent magnets are buried inside a conductor bar, the bridge portion having a narrow portion and a wide portion in which a permanent magnet burying hole is provided in a radial direction of a rotor core. And a permanent magnet of the same polarity is buried in this to form one rotor magnetic pole, and a magnetic flux is generated between the end face of the permanent magnet and the bridge portion A. In addition to providing a space for preventing short circuits, By providing two bridge portions B in the radial direction of the rotor core with a barrier slot for preventing magnetic flux short-circuiting between permanent magnet burial holes for burying permanent magnets of different polarities, permanent magnet end faces are provided. Improves the performance of the motor by preventing magnetic flux short circuit inside, and the shrinkage strain in the radial direction of the rotor core outer diameter after aluminum die-casting becomes very small. Therefore, it is possible to reduce the number of man-hours by eliminating the need for cutting the outer diameter of the rotor core.

According to a second aspect of the present invention, there is provided a stator in which a winding is wound around a stator core, and a stator which is rotatably opposed to an inner cylindrical surface of the stator core, and is provided with an outer periphery of the rotor core. A plurality of conductor bars located in the vicinity and short-circuit rings located at both axial end surfaces of the rotor core are integrally molded by aluminum die casting to form a starting cage conductor, and inside the conductor bar. A motor comprising a rotor having a plurality of permanent magnets embedded therein, wherein permanent magnet embedded holes are arranged so as to abut each other in a mountain shape with two bridge portions C provided in a radial direction of a rotor core. By embedding permanent magnets of the same polarity in this, one rotor magnetic pole is formed, and a space portion for preventing a magnetic flux short circuit is provided between the end face of the permanent magnet and the bridge portion C, and adjacent to each other. Embedding permanent magnets of different polarity By providing two bridge portions B in the radial direction of the rotor core with a barrier slot for preventing magnetic flux short-circuiting between the permanent magnet embedding holes, the rotor core outer diameter at the center of the rotor magnetic pole can be reduced. The shrinkage strain in the radial direction is further reduced, and the size of the gap with the inner diameter of the stator core can be determined more accurately, so that the motor has the effect of further reducing noise and vibration.

According to a third aspect of the present invention, there is provided a stator in which a winding is wound around a stator core, and a stator which rotates freely facing an inner cylindrical surface of the stator core. A plurality of conductor bars located in the vicinity and short-circuit rings located at both axial end surfaces of the rotor core are integrally molded by aluminum die casting to form a starting cage conductor, and inside the conductor bar. In a two-pole self-starting permanent magnet synchronous motor comprising a rotor having a plurality of embedded permanent magnets,
After forming a starting cage conductor by aluminum die-casting on the rotor core, the permanent magnet buried hole is formed so that the radial gap with the permanent magnet gradually increases from the end of the rotor magnetic pole toward the center. In this method, the permanent magnet is buried in the hole in the radial direction by aluminum die casting, but the permanent magnet can be easily inserted into the rotor core without any trouble. This has the effect of simplifying the operation.

According to a fourth aspect of the present invention, there is provided a stator in which a winding is wound around a stator core, and the stator is freely rotated to face an inner cylindrical surface of the stator core, and an outer periphery of the rotor core is provided. A plurality of conductor bars located in the vicinity and short-circuit rings located at both axial end surfaces of the rotor are integrally formed by aluminum die casting to form a starting cage conductor, and a plurality of conductor bars are provided inside the conductor bar. In a two-pole self-starting type permanent magnet synchronous motor comprising a rotor in which two permanent magnets are embedded, an ellipse whose outer diameter of the rotor core gradually increases from the end of the rotor magnetic pole toward the center. This is a manufacturing method in which a starting cage conductor is formed by aluminum die casting on a rotor core formed into a shape, and then a permanent magnet is attached.The radial shrinkage strain of the outer diameter of the rotor core by aluminum die casting is reduced. There The gap between the inner diameter of the rotor and the inner diameter of the rotor can be accurately determined only by punching out a magnetic steel sheet mold, eliminating the need to cut the outer diameter of the rotor core and simplifying the aluminum die-casting operation to increase productivity. It has the effect of being able to.

The invention described in claim 5 is the first invention.
To the invention according to any one of claims 4 to 5,
Since the permanent magnet is formed of a rare earth magnet, a strong magnetic force is obtained, and the rotor and the electric motor can be reduced in size and weight as a whole.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a self-starting permanent magnet synchronous motor according to the present invention and a method of manufacturing the same will be described below with reference to the drawings. The same components as those in the related art are denoted by the same reference numerals, and detailed description is omitted. Since the stator has the same configuration as a general self-starting permanent magnet type synchronous motor, description of the stator is omitted.

(Embodiment 1) A description will be given with reference to FIGS. FIG. 1 is an axial sectional view of a rotor of a self-starting permanent magnet type synchronous motor according to Embodiment 1 of the present invention, and FIG. 2 is a radial sectional view of FIG. FIG. 3 is a partially enlarged view of a portion M in FIG.

1 to 3, reference numeral 1 denotes a rotor, and 2 denotes a rotor core made of laminated electromagnetic steel sheets. Reference numeral 3 denotes a conductor bar, which is integrally formed with the short-circuit rings 4 located at both axial ends of the rotor core 2 by aluminum die casting to form a starting cage conductor. Reference numeral 5 denotes a permanent magnet, and a permanent magnet embedding hole 6 provided in the axial direction of the rotor core 2
The two plate-shaped permanent magnets 5 are connected to the bridge A of the rotor core 2.
One rotor magnetic pole is formed by arranging the rotor 7 so as to abut on a mountain shape with the 7 interposed therebetween, and the rotor as a whole forms two rotor magnetic poles.

Here, the bridge portion A of 7 is a narrow portion 7
It is designed to have a and a portion 7b whose width increases from the outer diameter side toward the outer diameter side. A magnetic flux short circuit between the opposite poles on the front and back of the permanent magnet 5 is prevented by magnetic saturation of the narrow portion 7a.

The end face 5a of the permanent magnet 5 and the bridge A
Since the space portion 8 is provided between the permanent magnet 7 and the magnetic head 7, a magnetic flux short circuit between different poles in the end face 5 a of the permanent magnet 5 can be prevented.

Reference numeral 9 denotes a barrier slot provided between adjacent permanent magnets 5 of different polarities for preventing a magnetic flux short circuit, in which aluminum 10 is filled with aluminum die casting.
The bridge portion B11 of the rotor core 2 between the barrier slot 9 and the permanent magnet burying hole 6 is set to a narrow width, and this portion is magnetically saturated to prevent a magnetic flux short circuit between the permanent magnets 5 having different polarities. And a permanent magnet 5
A space portion 12 is provided between the end surface of the permanent magnet 5 and the bridge portion B11 to prevent a magnetic flux short circuit between different poles in the end surface of the permanent magnet 5. Reference numeral 13 denotes a nonmagnetic end plate for protecting the permanent magnet 5, which is fixed to both end surfaces of the rotor core 2 by rivet pins 14. Reference numeral 15 denotes a shaft hole of the rotor.

To manufacture the rotor 1 having the above-described structure, a starting cage conductor is formed on the rotor core 2 formed by laminating electromagnetic steel sheets by aluminum die casting, and then the permanent magnet 5 is inserted into the permanent magnet burying hole 6. Is embedded and the end plate 1 is
3 is fixed to the both end faces of the rotor core 2.

After the aluminum die-casting, the short-circuit ring shrinks in the radial direction when the aluminum cools, and accordingly, the rotor core 2 also receives shrinkage stress in the inner diameter direction. . However, as shown in FIG. 2, the bridge portion B11 of the rotor core 2 is near the barrier slot 9.
Are provided at two locations with the barrier slot 9 interposed therebetween, and therefore have high strength against shrinkage stress, so that the radial shrinkage strain of the outer diameter of the rotor core 2 is small.

On the other hand, since there is only one bridge portion A7, the distortion in the radial direction of the rotor core 2 at this portion becomes large. Therefore, in order to prevent this, the radial length of the narrow portion 7a for preventing the magnetic flux short circuit due to the magnetic saturation of the bridge portion A7 is shortened, and the wide portion 7b following the narrow portion 7a is provided. By increasing the strength against the contraction stress in the radial direction, distortion is prevented in the radial direction of the rotor core 2 near the bridge portion A7.

As a result, the outer diameter of the rotor core 2 can be secured to a shape substantially close to a perfect circle. Therefore, when the electromagnetic steel plate of the rotor core 2 is punched in a mold, the outer diameter is previously set to the inner diameter of the rotor core. If a predetermined gap is obtained, a step of cutting the outer diameter of the rotor core after aluminum die-casting to obtain a predetermined gap can be omitted.

Although the present embodiment has been described by taking the example of a two-pole rotor, the present invention is not limited to this, and the rotor may have another number of poles such as four poles.

Although the permanent magnet is described as having a flat shape, it may have another shape such as an arc shape.

As described above, according to the invention described in the first embodiment, a short circuit of the magnetic flux between the permanent magnets is prevented, and high performance can be ensured. A self-starting permanent magnet synchronous motor can be provided.

(Embodiment 2) A description will be given with reference to FIG. FIG.
FIG. 6 is a radial cross-sectional view of a rotor of a self-starting permanent magnet synchronous motor according to Embodiment 2 of the present invention.

In FIG. 4, reference numeral 21 denotes a bridge portion C of the rotor core 2, and two flat permanent magnets 5 having the same polarity are arranged so as to abut each other in a mountain shape with the two bridge portions C21 interposed therebetween. Thus, one rotor magnetic pole is formed, and the entire rotor forms two rotor magnetic poles. Reference numeral 22 denotes a space between the two bridge portions C21.
21 is designed to be narrow so as to prevent a magnetic flux short circuit between different poles on the front and back of the permanent magnet 5.

Reference numeral 23 denotes a space provided between the end face of the permanent magnet 5 and the bridge portion C21, and prevents a magnetic flux short circuit between different poles in the end face of the permanent magnet 5 as in the first embodiment. ing.

With the above configuration, the radial shrinkage distortion near the bridge portion C21 of the rotor core 2 due to the radial shrinkage of the short-circuit ring after aluminum die-casting is because two bridge portions C are provided. Since the strength becomes stronger as compared with the case of the single bridge portion in the first embodiment, the strength hardly occurs, and the outer diameter of the rotor core 2 after the aluminum die-casting is further improved in roundness, and the outer diameter of the rotor core 2 is reduced. Of the motor can be made uniform, and the noise and vibration of the motor can be further reduced.

(Embodiment 3) A description will be given with reference to FIGS.

FIG. 5 is a plan view of an electromagnetic steel plate of a rotor of a self-starting permanent magnet synchronous motor according to Embodiment 3 of the present invention. FIG. 6 is a plan view of an electromagnetic steel plate of another rotor according to the third embodiment.

In FIG. 5, reference numeral 31 denotes an electromagnetic steel sheet. After a predetermined number of such steel sheets are laminated to form a rotor core, a starting cage conductor is formed on the rotor core by aluminum die casting. Reference numeral 32 denotes a conductor bar slot in which the conductor bar of the starting cage conductor is filled, and reference numeral 33 denotes a permanent magnet burying hole.

After aluminum die-casting, two permanent magnets of the same polarity are embedded in the two permanent magnets 33 as shown by a two-dot chain line to form one rotor magnetic pole. Also lower 2
Permanent magnets of different polarities are also embedded in the permanent magnet embedded holes 33, and the rotor as a whole constitutes two rotor magnetic poles. Reference numeral 34 denotes a bridge portion D, which is narrowed to cause magnetic saturation and prevent a magnetic short circuit between the opposite poles of the permanent magnet. Numeral 35 denotes a barrier slot for preventing magnetic flux short-circuit, which is interposed between the upper and lower permanent magnet buried holes 33 and narrows the width of two bridge portions E36 formed between the permanent magnet buried holes 33. By setting, this portion is magnetically saturated to prevent a magnetic flux short circuit between adjacent permanent magnets of different polarities. Reference numeral 37 denotes a hole for passing a rivet pin for fixing the end plate, and reference numeral 38 denotes a shaft hole.

Here, the hole width in the radial direction of the permanent magnet burying hole 33 is equal to the gap P between the permanent magnet burying hole 33 and the permanent magnet indicated by the two-dot chain line at the end of the rotor magnetic pole (ie, near the barrier slot 36). ₁ small, continue to gradually increase the clearance toward the center of the rotor poles (i.e. near the bridge portion D34), set to reach the _{P 2 (P 2> P 1} ).

In the drawings, the gaps are exaggerated for easy understanding.

A rotor core is formed by punching out a predetermined number of electromagnetic steel sheets having the above-described shape with a die to form a rotor core, forming a starting cage conductor by aluminum die casting, and then mounting a permanent magnet. After the aluminum die-casting, the short-circuit rings (not shown) formed at both axial ends of the rotor core of the starting cage conductor cool down after the aluminum die-casting, and shrink in the radial direction. The contraction stress of the short-circuit ring causes the contraction in the radial direction. At that time, permanent magnet burial hole 33
In the magnetic pole end portion of the rotor, the strength is strong because there are two bridge portions E36 and the hole width hardly changes, but the strength is weak against shrinkage stress because the bridge portion 35 is only one at the center of the magnetic pole. The hole width of the permanent magnet is reduced. However, since the magnetic pole center portion of the permanent magnet burying hole 33 is made of an electromagnetic steel sheet having a large gap with the permanent magnet,
It does not occur that the hole width of this portion becomes too narrow to insert the permanent magnet, and the rotor can be assembled smoothly.

In FIG. 6, one rotor magnetic pole is formed by two flat permanent magnets having the same polarity. However, one rotor magnetic pole is formed by using three or more flat permanent magnets. Alternatively, the shape of the permanent magnet may be another shape such as an arc shape.

In FIG. 6, one rotor magnetic pole is formed only by one arc-shaped permanent magnet as indicated by a two-dot chain line, and the entire rotor is a two-pole rotor formed by two arc-shaped permanent magnets. It is an electromagnetic steel sheet of a rotor iron core that forms a magnetic pole. Similar to be omitted the description of the individual code described in FIG. 5, to narrow the gap to Q ₁ and the permanent magnet burying hole 43 and the permanent magnets at the ends of the rotor poles, the center portion of the rotor magnetic poles, gaps Q ₂ (Q ₂
> Q ₁ ) is set wide, so that the same effect as in the example of FIG. 5 can be obtained.

Further, in the manufacturing method of the present invention, since the aluminum die-casting is performed without mounting the permanent magnet or the end plate, the work is simple and it is difficult to produce defective products, so that the productivity can be improved.

(Embodiment 4) A description will be given with reference to FIG.

FIG. 7 is a plan view of a magnetic steel sheet of a rotor of a self-starting permanent magnet type synchronous motor according to Embodiment 4 of the present invention.

In FIG. 7, reference numeral 51 denotes an electromagnetic steel plate. A predetermined number of the magnetic steel plates are laminated to form a rotor core, and then a starting cage conductor is formed on the rotor core by aluminum die casting. 52 is a slot for a conductor bar, 53 is a hole for burying a permanent magnet, 54 is a bridge portion F, 55 is a barrier slot for preventing magnetic flux short circuit, and 56 is a bridge portion G.
Reference numeral 57 denotes a hole through which a rivet for fixing the end plate is inserted.
Is a shaft hole. Each part plays a role similar to that of the third embodiment, and a description thereof will be omitted to avoid duplication. In addition, a permanent magnet inserted after aluminum die casting is indicated by a two-dot chain line, and the rotor forms two rotor magnetic poles.

Here, the outer diameter of the electromagnetic steel plate 51 is set to an outer diameter R ₁ at the end of the rotor magnetic pole so as to have a predetermined gap size between the inner diameter of the stator core and the center of the rotor magnetic pole. The outer diameter at the center of the rotor magnetic pole is set to reach R ₂ (R ₂ > R ₁ ).
A rotor steel core is formed by punching out a predetermined number of electromagnetic steel sheets having the above-described shape and laminating the same to form a starting cage-shaped conductor by aluminum die casting, and then mounting a permanent magnet.

After aluminum die-casting, short-circuit rings (not shown) formed on both end surfaces in the axial direction of the rotor core of the starting cage conductor cool down and shrink in the radial direction. Also contracts in the radial direction due to the contraction stress of the short-circuit ring.

At this time, the rotor of the electromagnetic steel sheet 51 of the rotor core
The pole tip has two bridges G56,
Outside the rotor core because of its strong strength against shrinkage stress
Diameter R ₁Hardly changes. But at the center of the rotor pole
Has only one bridge portion F54, so the strength is weak.
Outer diameter R of rotor core_TwoReceives shrinkage stress and
Shrink. At this time, the outer diameter R_TwoDimension after contraction is R₁To
If set so that the entire outer diameter of the rotor core
Diameter is R₁Of a substantially perfect circle.

In FIG. 7, the outer diameter R after contraction is shown.₁Circle of
Is shown by a two-dot chain line,₁And R _TwoUnderstand the dimensional difference
It is exaggerated for ease of illustration.

In FIG. 7, one rotor magnetic pole is formed by two plate-shaped permanent magnets having the same polarity. However, as shown in FIG. 6, one rotor is formed by one arc-shaped permanent magnet. A magnetic pole may be formed.

As described above, according to the present invention, since the outer diameter of the rotor core after aluminum die-casting is almost a perfect circle, the gap with the inner diameter of the stator core can be formed by punching in advance with a punching die. In addition, it is not necessary to cut the outer diameter of the rotor core to determine the dimensions, thereby reducing man-hours.

In addition, since the aluminum die casting is performed without the permanent magnet or the end plate attached, the work is simple and it is difficult for defective products to be produced, and the productivity can be improved in combination with the both.

(Embodiment 5) Although not shown, if the permanent magnet is formed of a rare earth magnet such as neodymium / iron / boron, a strong magnetic force can be obtained, so that the rotor and the motor as a whole are reduced in size and weight. be able to.

[0062]

As described above, the invention according to claim 1 is
A permanent magnet of the same polarity is arranged so as to abut against the mountain shape with a radial bridge portion having a narrow portion and a wide portion of the rotor core sandwiched therebetween, and between the end face of the permanent magnet and the bridge portion. The structure to provide a space for preventing magnetic flux short circuit prevents magnetic flux short circuit inside the rotor and eliminates the need to cut the outer diameter of the rotor core, thus providing a high-performance and inexpensive self-starting permanent magnet synchronous motor. Can be provided.

According to the second aspect of the present invention, since the permanent magnets of the same polarity are arranged so as to sandwich the two bridges provided on the rotor core, the rotor core at the center of the rotor magnetic poles is provided. The radial shrinkage strain of the outer diameter is further reduced,
Since the gap size between the inner diameter of the stator core and the inner diameter of the stator can be more accurately determined, the noise and vibration of the motor can be further reduced.

According to a third aspect of the present invention, in the two-pole permanent magnet rotor, the permanent magnet burying hole is formed such that the radial gap between the permanent magnet and the permanent magnet gradually increases from the end to the center of the rotor magnetic pole. In the rotor core formed to be large,
Since the starting cage-shaped conductor is formed by aluminum die-casting and the permanent magnet is mounted, the permanent magnet can be easily inserted even if the rotor core shrinks in the radial direction after aluminum die-casting. In addition to this, the aluminum die-casting operation can be simplified and the productivity can be improved.

According to a fourth aspect of the present invention, in the two-pole permanent magnet rotor, the outer diameter of the rotor core is formed in an elliptical shape such that the outer diameter gradually increases from the end of the rotor magnetic pole toward the center. After the starting cage-shaped conductor is formed by aluminum die casting on the rotor core, the permanent magnet is mounted, so that even if the outer diameter of the rotor core after aluminum die casting shrinks in the radial direction, Uniform clearance between the stator core inner diameter can be ensured, eliminating the need to cut the rotor core outer diameter.Also, aluminum die-casting work is easy and defective products are less likely to appear, increasing productivity, high performance and low cost self-starting. A permanent magnet type synchronous motor can be provided.

According to a fifth aspect of the present invention, there is provided the invention according to any one of the first to fourth aspects, further comprising a permanent magnet formed of a rare-earth magnet, thereby providing a strong magnetic force. Therefore, the entire rotor and electric motor can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a rotor of a self-starting permanent magnet synchronous motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view in the radial direction of FIG. 1;

FIG. 3 is a partially enlarged view of a portion C in FIG. 2;

FIG. 4 is an axial sectional view of a rotor of a self-starting permanent magnet synchronous motor according to a second embodiment of the present invention.

FIG. 5 is a plan view of a magnetic steel sheet of a rotor of a self-starting permanent magnet synchronous motor according to a third embodiment of the present invention.

FIG. 6 is a plan view of an electromagnetic steel plate of another rotor of the self-starting permanent magnet type synchronous motor according to the third embodiment of the present invention.

FIG. 7 is a plan view of an electromagnetic steel plate of a rotor of a self-starting permanent magnet type synchronous motor according to Embodiment 4 of the present invention.

FIG. 8 is a radial sectional view of a conventional self-starting permanent magnet synchronous motor.

FIG. 9 is an axial sectional view of a conventional self-starting permanent magnet type synchronous motor.

10 is a partially enlarged view of a portion A in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Rotor core 3 Conductor bar 4 Short-circuit ring 5 Permanent magnet 6 Permanent magnet burial hole 7 Bridge part A 8 Space part 9 Barrier slot 11 Bridge part B

Continued on the front page (72) Inventor Teruo Tamura 4-2-5 Takaida Hondori, Higashi-Osaka City, Osaka Prefecture Inside Matsushita Refrigeration Machinery Co., Ltd. Incorporated F term (reference) 5H621 AA01 AA03 GA01 GA04 HH01 HH10 JK05 5H622 AA01 AA03 CA02 CA07 CA12 CA13 CB05 CB06 PP03 PP10 PP11 PP19

Claims (5)

[Claims] A stator having a winding wound around a stator core;
Freely rotating facing the inner diameter cylindrical surface of the stator core,
A plurality of conductor bars located near the outer periphery of the rotor core and short-circuit rings located at both axial end surfaces of the rotor core are integrally formed by aluminum die casting to form a starting cage conductor, and A motor comprising a rotor in which a plurality of permanent magnets are buried inside a conductor bar, the bridge portion having a narrow portion and a wide portion in which a permanent magnet burying hole is provided in a radial direction of a rotor core. And a permanent magnet of the same polarity is buried in this to form one rotor magnetic pole, and a magnetic flux is generated between the end face of the permanent magnet and the bridge portion A. Two bridge portions are provided in the radial direction of the rotor core with a barrier slot for preventing a magnetic flux short-circuit between adjacent permanent magnet burying holes for burying permanent magnets of different polarities. Set B Self-starting permanent magnet synchronous motor, characterized in that the. 2. A stator having windings wound around a stator core,
Freely rotating facing the inner diameter cylindrical surface of the stator core,
A plurality of conductor bars located near the outer periphery of the rotor core and short-circuit rings located at both axial end surfaces of the rotor core are integrally formed by aluminum die casting to form a starting cage conductor, and An electric motor comprising a rotor having a plurality of permanent magnets embedded inside a conductor bar, wherein the permanent magnet embedded holes are butted into a mountain shape with two bridge portions C provided in the radial direction of the rotor core interposed therebetween. And a permanent magnet of the same polarity is buried therein to form one rotor magnetic pole, and a space for preventing a magnetic flux short circuit is formed between the end face of the permanent magnet and the bridge portion C. In addition to the above, two bridge portions B are provided in the radial direction of the rotor core between barrier holes for preventing short-circuiting of magnetic flux between permanent magnet burying holes for burying permanent magnets of adjacent polarities. And self Dogata permanent magnet synchronous motor. 3. A stator having windings wound around a stator core,
Freely rotating facing the inner diameter cylindrical surface of the stator core,
A plurality of conductor bars located near the outer periphery of the rotor core and short-circuit rings located at both axial end surfaces of the rotor core are integrally formed by aluminum die casting to form a starting cage conductor, and In a two-pole self-starting permanent magnet type synchronous motor including a rotor having a plurality of permanent magnets embedded inside a conductor bar, a permanent magnet embedded hole has a radial gap between the permanent magnet and an end of the rotor magnetic pole. The rotor core formed so that it gradually becomes larger from the part toward the center,
A manufacturing method comprising: forming a starting cage conductor by aluminum die-casting; and mounting a permanent magnet. 4. A stator having windings wound around a stator core,
Freely rotating facing the inner diameter cylindrical surface of the stator core,
A plurality of conductor bars located near the outer periphery of the rotor core and short-circuit rings located at both axial end surfaces of the rotor are integrally formed by aluminum die casting to form a starting cage conductor, and the conductor In a two-pole self-starting permanent magnet synchronous motor comprising a rotor having a plurality of permanent magnets embedded inside a bar, the outer diameter of the rotor core gradually increases from the end of the rotor magnetic pole toward the center. A manufacturing method characterized in that a starting cage conductor is formed by aluminum die casting on a rotor core formed in an elliptical shape having a large size, and then a permanent magnet is mounted. 5. The self-starting permanent magnet type synchronous motor according to claim 1, wherein the permanent magnet is formed of a rare earth magnet.