JP2000116042A - Permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve torque and efficiency by composing a rotor core by laminating steel sheets, forming an open part that communicates with an air gap at one end of a hole for burying the steel sheet, and forming a closed part at the other end part. SOLUTION: Polygonal cut-out parts 17a, 17b, 17c, and 17d where one permanent magnet side is open and the other is closed are provided between holes 5k-5n for burial, and each of the cut-out parts 17a, 17b, 17c, and 17d composes closed and open parts with less leakage of magnetic flux, thus composing an open part at one end part of a permanent magnet to be buried and a closed part at the other for the shape of a rotor core 1, performing lamination so that the open part and the closed part alternately overlap each other when laminating a blank, and alternately combining the closed part and the open part and hence reducing the yoke of the end face of the permanent magnet by half and increasing magnetic reluctance, suppressing a reverse pole component to approximately 50%, increasing the effective magnetic flux of the permanent magnet motor, and improving torque and efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet motor having a permanent magnet embedded in a rotor.

[0002]

2. Description of the Related Art As shown in FIG. 12, a rotor having a permanent magnet embedded therein is provided with an embedding hole 35 corresponding to the number of poles and the shape of the permanent magnet 32 in a punched plate 34 made of silicon steel plate or the like. A rotor core is formed by laminating and fixing a plurality of plates, and a permanent magnet 32 is inserted into the embedding hole 35. Each of the permanent magnets 32 is fitted and fixed in an embedding hole 35 of a punched plate 34. Various shapes such as an arc shape and a flat plate shape are used for the shape of the permanent magnet 32 and the embedding hole 35.

An example of the application is disclosed in, for example, Japanese Patent Laid-Open No. 9-2009.
No. 85 discloses this. FIG. 13 is a plan view of the rotor. The rotor (field portion) 33 is orthogonal to a pole center line P provided radially from the axis at an equiangular pitch on the outer diameter side of a disk-shaped silicon steel plate. A side that gives mechanically sufficient strength and leakage magnetic flux of the permanent magnets 36 between the left and right symmetrical rectangular permanent magnet insertion holes (embedding holes) 37 and the permanent magnet insertion holes 37. A plurality of punched plates 38 formed by punching out a substantially triangular leakage magnetic flux prevention hole 41 in which the connecting portion 39 and the outer connecting portion 40 are left uncut and a hole for fitting a shaft (not shown) at the center are laminated in the axial direction. And six permanent magnets 36 fitted into the embedding holes 37 so that the magnetic poles adjacent to the rotor core 43 have different polarities, and inserted into the leakage magnetic flux prevention holes 41. Functional members 42 made of a temperature-sensitive magnetic material having a negative magnetic permeability and a negative temperature coefficient.

The entire rotor core 43 may be made of an amorphous magnetostrictive material having a negative magnetostriction constant. In this case, tension is applied to the entire rotor core 43 by the high-speed rotation of the field part (rotor) 33, and the magnetic permeability of the entire rotor core 43 decreases, thereby weakening the field. Further, it is disclosed that the permanent magnet insertion holes 37 and the permanent magnets 36 are not limited to rectangles but may be, for example, fan-shaped.

[0005]

According to the above-mentioned method, as shown in FIG.
Since the yoke portion 43 exists between the circumferential end surfaces of the permanent magnets 32 embedded in the yoke 5, a pair of magnetic poles (N, S) are generated in the yoke portion 43 due to the magnetic flux leaking from the end surfaces of the permanent magnets.

The magnetic flux density waveform in this case will be described with reference to FIG.
A polar waveform 51 and an S-polar waveform 52 are formed in a symmetrical relationship, and a waveform 53 formed by a pair of magnetic poles due to a leakage magnetic flux
54 are formed. In this case, the magnetic pole formed by the leakage magnetic flux has a polarity opposite to that of the main magnetic pole, so that the main magnetic flux is canceled. For this reason, the effective magnetic flux decreases, and the generated torque of the motor decreases. Therefore, it has been difficult to obtain a motor with high torque and high efficiency.

The rotor 33 disclosed in Japanese Patent Application Laid-Open No. 9-200985 has a functional member 42 made of a temperature-sensitive magnetic material having a magnetic permeability having a negative temperature coefficient in a leakage flux preventing hole 41. Since the structure is such that... Are inserted, man-hours are required for assembling, and the number of parts is large and expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a high torque and high efficiency permanent magnet type motor.

[0009]

According to the first aspect of the present invention, a stator and a plurality of permanent magnets are provided on the rotor core so as to face each other via an air gap. And a rotor formed by being embedded in the embedding hole, wherein the rotor core is configured by laminating steel plates, and one end of the embedding hole of the steel plate. , An open portion communicating with the air gap is formed, and a closed portion is formed at the other end of the permanent magnet type motor.

According to the means of the invention according to claim 2,
The permanent magnet type motor is characterized in that the open part and the closed part in the adjacent embedding hole are formed to be reversed in the circumferential direction.

Further, according to the means of the invention according to claim 3,
The permanent magnet type motor is characterized in that the open part and the closed part in the adjacent embedding hole are formed in the same circumferential direction.

Further, according to the means of the invention according to claim 4,
The opening portion and the closing portion are stacked so as to coexist with each other.

According to the invention of claim 5,
The opening portion and the closing portion are alternately laminated for every predetermined number of steel plates to be laminated.

Further, according to the means of the invention according to claim 6,
The permanent magnet type motor is characterized in that the steel plates are alternately laminated on the front and back sides every predetermined number of sheets.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

An interior permanent magnet motor (hereinafter abbreviated as IPM) having a permanent magnet embedded in a rotor core of a rotor is usually configured as shown in a plan view in FIG. That is, a rotor core 1 is formed by laminating a plurality of punched sheets 4 formed of a silicon steel plate, and the permanent magnets 2 are fitted and arranged in embedding holes 5 formed in approximately the same manner. ing. The embedded permanent magnet 2 usually has I
The PM is formed to have a predetermined thickness so as to have a sufficient strength to prevent demagnetization or demagnetization of a magnetomotive force from a stator (not shown) during operation of the PM.

On the other hand, the rotor core 1 in which each of the permanent magnets 2 is embedded is usually made of a material having a high magnetic permeability, and the magnetic flux of the embedded permanent magnet 2 is reduced by an air gap between a stator (not shown) and the rotor 3. To form a magnetic path. In this case, in order to minimize the leakage magnetic flux between the adjacent permanent magnets having different polarities of the rotor 3 and to secure a large amount of magnetic flux effective for torque as a motor, the gap width t between the permanent magnets 2 is required. Path width m between end of permanent magnet 2 and rotor core 1 and outer peripheral surface
Is configured to be as narrow as possible.

FIG. 2 is a plan view showing a configuration of a quadrupole rotor according to an embodiment of the present invention.

The rotor 3A includes a rotor core 1A formed by stacking punched sheets 4A of high-tensile steel such as a silicon steel plate, and embedding holes 5a to 5d provided in the rotor core 1A. And the permanent magnets 2a to 2d. Opening portions 7a and 7b are formed at one end between adjacent embedding holes 5a and 5b and between 5c and 5d, and closed portions 8a and 8b (between the embedding holes 5a and 5b and between 5c and 5d). (A yoke portion of the end face of the permanent magnetic charge). That is, according to the order in which the embedding holes 5a to 5d of the rotor core 1 are provided, the opening portions 7a,
7b and the closing parts 8a and 8b are provided alternately.

FIG. 3A shows a laminated structure of a quadrupole rotor shown in FIG.
3 (b) is a side view of the laminated structure of the quadrupole rotor viewed from the direction of arrow X in FIG.

That is, the rotor core 1A is formed by alternately stacking the punched plates 4A with the front and back layers for each layer, or rotating the punched plates 4A in the circumferential direction by an angle of one pole to open the opening portions 7a, 7b and closing portions 8a, 8b.
Are alternately stacked.

FIG. 4 is a modification of FIG. 3. FIG. 4 (a) is a side view of the laminated structure of the quadrupole rotor viewed from the direction of arrow Y in FIG. 2, and FIG. FIG. 3 is a side view of the laminated structure of the child as viewed from an arrow X direction in FIG. 2.

3 (a) and 3 (b), the blanks 4A.
Although the sheets are alternately stacked one by one, in FIGS. 4A and 4B, two sheets are alternately stacked. Note that the number of stacked layers is not limited to two, and a similar effect can be obtained by alternately combining the same number of the arbitrary number of sheets.

That is, similarly, as shown in FIGS. 5 (a) and 5 (b), the same effect can be obtained by laminating punched plates 4A...

Next, the magnetic flux density waveform of the embodiment shown in FIG. 2 will be described. FIG.
FIG. 6B is a waveform diagram showing a surface magnetic flux density waveform on the side of the punched plate when viewed centering on 8b. FIG. is there.

That is, FIG. 6 (a) shows a waveform in the range shown in the odd-numbered sheet in FIG. 3 (a), where closed portions are formed on the side surfaces of the punched plates 4A. An opening is formed. Therefore, the main pole (N) and the main pole (S) of the permanent magnet form symmetrical waveforms 11 and 12,
Since the closing portion 8b is between them, the waveforms 13 and 14 of the magnetic poles due to the leakage magnetic flux are formed. On the other hand, since both ends are voids at the open portions, the magnetic resistance is increased by air, and a waveform 15 is obtained in which the reverse pole component is reduced.

On the other hand, in FIG. 6B, FIG.
Are open in the range illustrated in the even-numbered sheet in FIG. 7, where an open portion is formed on the side surface of the blank 4A, and closed portions are formed at both ends. Therefore, the permanent magnet 2
The main magnetic poles (N) and main magnetic poles (S) of a and 2b have symmetrical waveforms 1
1 and 12 are formed, and the gap between them is an open portion 7a, so that there is an air gap, so that the magnetic resistance is increased by air, and a waveform 15 in which the reverse pole component is reduced is obtained. On the other hand, since both ends are the closed portions 8a and 8b, the magnetic pole waveforms 13 and 14 due to the leakage magnetic flux are formed.

FIGS. 7A and 7B are side views of a modified example of the rotor core 1, in which the number of poles / 2 is equal to the open portion 7.
This is an example of a case where the punched plates 4A shown in FIG. 2 that are a and 7b are stacked alternately without being turned upside down or shifted by one pole.

In each of the embodiments described above, a four-pole rotor has been described. However, as shown in FIG. 8, a six-pole rotor can also be applied. Also in this case 4
Similarly to the polar rotor configuration, the rotor 3B is embedded in a rotor core 1B formed by stacking punched plates 4B,... And embedding holes 5e to 5j provided in the rotor core 1B. And permanent magnets 2e to 2j. Embedding holes 5e-5
j has open ends 7c to 7e (embedding holes 5e,
5j, 5f, 5g, 5h, 5i), and the other end is closed (yoke portion of the end face of the permanent magnetic charge) 8c to 8e (embedding holes 5e, 5f, 5g, 5h) , 5i, 5j). The embedding holes 5e to 5j are provided corresponding to the number of permanent magnets 2e to 2j corresponding to the number of poles.

Further, adjacent embedding holes 5e and 5f
In, the adjacent portion is formed in the closing portion 8c, and the non-adjacent portion is formed in the closing portions 7c and 7d. On the other hand, in the embedding hole 5e and the embedding hole 5j, an adjacent portion is formed in the open portion 7c, and non-adjacent portions are formed in the open portions 8c and 8e.
That is, according to the order in which the embedding holes 5e to 5j of the rotor core 1 are provided, the opening portions 7c and 7e and the closing portions 8c and 8e are provided.
Are provided alternately.

In each of the above embodiments, the closing portion 8
Although no particular processing is applied to a to 8e, FIG.
If the cutouts 16a to 16e are provided in a semicircular shape from the outer peripheral side of the blanks 4A and 4B as shown in (b), the leakage magnetic flux from the adjacent permanent magnet can be reduced.

Further, as shown in FIG.
one of the permanent magnet sides is opened between k to 5n,
Polygonal cutouts 17a, 17b, 17 closing the other
c, 17d, each notch 17a, 17b, 17
Since each of c and 17d is one, a closed part and an open part with little leakage flux can be configured.

According to the above-described configuration, the shape of the rotor core 1 is configured such that an open portion is formed at one end of the permanent magnet to be embedded, and a closed portion is formed at the other end. The closures are stacked alternately. This results in a structure in which closed parts and open parts are alternately combined in the stacked state.

With such a configuration, the number of yokes on the end faces of the permanent magnets 2a to 2j where the leakage magnetic flux is generated can be reduced to half compared with the conventional case, so that the mine resistance is increased and the reverse pole component is reduced. It is suppressed to about 50%. Therefore, the effective magnetic flux of the permanent magnet type motor increases, and high torque and high efficiency can be achieved.

Further, since the closing portion of the blanking plate acts as a fixing portion for the permanent magnet, there is no danger that the permanent magnet will fly out due to centrifugal force or the like when the rotor 3 rotates.

Further, if the open portion of the blank is filled with a non-magnetic material, the outer periphery of the rotor core becomes cylindrical, and wind loss generated from the open portion during rotation can be reduced.

Further, as shown in FIG. 11, the punched plate 4A on which the rotor core 1 is laminated is different from the open portion and the closed portion only by one at each end, so that the permanent magnet due to centrifugal force or the like during rotation can be formed. The risk of popping out can be eliminated.

Further, although not shown, a rotor core laminated by sandwiching the upper and lower surfaces of a laminated punched plate using a punched plate as an outermost layer in a non-magnetic material having an opening for embedding without an opening. The same effect can be obtained by the above.

Further, by using a high-tensile steel as the material for the punching of the rotor core, it is possible to reduce breakage of the bridge portion and the like when the punching is pressed.

[0040]

According to the present invention, in the permanent magnet type motor, the leakage magnetic flux generated in the yoke between the permanent magnet end faces of the rotor core can be reduced, and the pair of magnetic pole levels generated by the leakage magnetic flux can be reduced. Can be reduced. Accordingly, the effective magnetic flux of the main pole increases, and high torque and high efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a permanent magnet type motor.

FIG. 2 is a plan view showing a configuration of a quadrupole rotor according to the embodiment of the present invention.

FIG. 3 (a) shows the lamination structure of a quadrupole rotor by an arrow Y in FIG. 2;
FIG. 3B is a cross-sectional side view of the stacked configuration of the quadrupole rotor viewed from the direction of arrow X in FIG. 2.

4A is a side view of another laminated structure of a quadrupole rotor viewed from the direction of arrow Y in FIG. 2, and FIG. 3B is a laminated structure of another quadrupole rotor shown in FIG. The side view seen from the X direction.

FIG. 5 (a) shows a laminated configuration of a quadrupole rotor by an arrow Y in FIG. 2;
FIG. 3B is a side view of the laminated structure of another quadrupole rotor viewed from the direction of arrow X in FIG. 2.

FIG. 6A is a waveform diagram showing a surface magnetic flux density waveform on the side of the punched plate centered on the closed portion, and FIG.

FIGS. 7A and 7B are side views of a modified example of the rotor core.

FIG. 8 is a plan view of a six-pole rotor configuration.

9A is a plan view illustrating an example in which a cutout portion is provided on the outer peripheral side of a punched plate, and FIG. 9B is a plan view illustrating another example in which a cutout portion is provided on the outer peripheral side of the punched plate.

FIG. 10 is a plan view in which a polygonal notch is provided on the outer peripheral side of a blank.

FIG. 11 is a side view in which only one sheet at each end of the blank is shifted.

FIG. 12 is a plan view of a rotor of a conventional permanent magnet motor.

FIG. 13 is a plan view of a rotor of a conventional permanent magnet motor.

FIG. 14 is an explanatory diagram showing generation of a pair of magnetic poles (N, S) due to leakage magnetic flux.

FIG. 15 is a magnetic flux density waveform diagram due to generation of a pair of magnetic poles (N, S) due to leakage magnetic flux.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor core, 2 ... Permanent magnet, 3 ... Rotor, 4 ... Blanking, 5 ... Embedding hole, 7 ... Open part, 8 ... Closed part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takanobu Kushihira 3-3-9 Shimbashi, Minato-ku, Tokyo F-term in Toshiba Abu E Corporation (reference) 5H621 AA03 BB07 GA01 GA04 HH01 HH09 JK02 5H622 AA03 CA02 CA07 CA10 CA13 CB03 CB05 PP03 PP11

Claims (6)

[Claims] 1. A stator having a stator and a rotor provided to face the stator with an air gap therebetween and formed by embedding a plurality of permanent magnets in embedding holes formed in a rotor core. In the permanent magnet type motor, the rotor core is formed by stacking steel plates, and an open portion communicating with the air gap is formed at one end of the embedding hole of the steel plate. A permanent magnet type motor characterized in that a closed portion is formed at the other end. 2. The permanent magnet type motor according to claim 1, wherein an open portion and a closed portion of the adjacent embedding hole are formed to be opposite in a circumferential direction. 3. The permanent magnet type motor according to claim 1, wherein the open portion and the closed portion in the adjacent embedding holes are formed in the same circumferential direction. 4. The permanent magnet type motor according to claim 1, wherein the open portion and the closed portion are stacked so as to be mixed. 5. The ice-magnet type motor according to claim 4, wherein the open portions and the closed portions are alternately stacked for every predetermined number of steel sheets to be stacked. 6. The permanent magnet motor according to claim 3, wherein the steel plates are alternately laminated on the front and back sides every predetermined number.