JP3832540B2 - Permanent magnet motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet motor for a motor used in an air conditioner, an automobile, or the like, and more particularly to a permanent magnet motor that enables effective use of reluctance torque.
[0002]
[Prior art]
For example, as shown in FIG. 10, the permanent magnet motor has a rotor 2 in a stator 1 having, for example, 24 slots that generates a rotating magnetic field, and the rotor 2 has the number of poles of the permanent magnet motor ( For example, four poles) of permanent magnets 3 are arranged in the circumferential direction along the outer diameter. In addition, 4 is a center hole for shaft insertion .
[0003]
In the structure of the rotor 2, the permanent magnet 3 has a plate shape along the q axis, and a path of magnetic flux (magnetic flux from the stator 1) from one q axis to the other q axis is secured, and Permanent magnet 3 is vertically interposed in the path of magnetic flux (magnetic flux from stator 1) from one d-axis to the other d-axis. With such a structure, a d-axis and q-axis inductance ratio (so-called salient pole ratio) can be obtained and reluctance torque is generated. Therefore, not only magnet torque but also reluctance torque can be expected. The permanent magnet motor provided with the rotor 2 is a three-phase four-pole motor. However, Japanese Patent Application Laid-Open No. 10-66285 describes a six-pole motor and should be used as a reference example of the above-described conventional example.
[0004]
[Problems to be solved by the invention]
However, in the permanent magnet motor, the d-axis and q-axis inductance ratio (so-called salient pole ratio) is extremely small, the reluctance torque hardly contributes to the motor torque, and the magnet torque mainly contributes to the motor torque. In order to increase the torque and efficiency, if a magnet is enlarged or a magnet having a strong magnetic force is used, the cost increases, and the amount of magnet used is also limited in consideration of the cost.
[0005]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a permanent magnet motor capable of increasing the reluctance torque to achieve high torque and high efficiency.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a permanent magnet motor having a rotor inside a stator for generating a rotating magnetic field as defined in claim 1 , wherein the rotor has a plate-like shape. along the magnet to the q-axis, and is buried at regular intervals only very few minutes along the outer periphery of the rotor, and perpendicular magnetization of the magnet relative to the q-axis, and the magnets adjacent the counter electrode side with the same polarity to form the equivalent polar to d-axis portion, it forms a slit to secure a magnetic path (flux road) from one q axis on the d-axis portion to the other q axis The d-axis and q-axis inductance ratio is increased by the slit.
[0007]
State as described in claim 2, in claim 1, before kissing slit is arcuate sectional shape, a cross-sectional bathtub shape or V-shape, towards their central portion to the center hole side shaft And are preferably formed in multiple layers at equal intervals in the d-axis direction.
[0008]
As described in claim 3, in claim 1 or 2, before the end of the shaft insertion central hole side Kemah Gunetto to form a flux barrier, the flux barrier above the magnets adjacent It is preferable to extend over the end on the shaft insertion center hole side.
[0009]
As described in claim 4, in claim 3, before notated parallax barrier is divided into two in the middle portion may be a pair of flux barriers.
[0010]
As described in claim 5, in claim 1, 2 or 3, between or between the slit and the flux barrier between the front kissing lit and the shaft insertion central hole, the core caulking on d-axis It is preferable that the rivet is made of a magnetic material.
[0011]
As described in claim 6, according to claim 1, 2 or 3, prior to and from or between the slit and the flux barrier kiss lit a core outer periphery of the rotor, on the d-axis It is preferable to pass a rivet for caulking the core and use the rivet as a magnetic material.
[0012]
The core according to any one of claims 1 to 6, wherein the rotor is formed by punching a core sheet made of an electromagnetic steel plate by an automatic press and automatically laminating it in a mold. , and the embedding hole of the magnet when the automatic pressing, the slit holes punched before Symbol rivet hole and the flux barrier holes and with between these holes and these holes and the core outer circumference of the rotor during, it is preferable to at least greater than the thickness of said core sheet.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In the figure, the same parts as those in FIG.
[0014]
As shown in FIGS. 1 to 3, the rotor 10 of the permanent magnet motor is elongated along the q-axis direction (plate-like) embedded magnet 11 in IPM mode, and, along a few minutes the core periphery the pole embedded at equal intervals Te, (see dashed line arrow in FIG. 3) while securing a magnetic path (from one of the q-axis to the other of the q-axis) from the stator 1, to increase the reluctance torque to the reserved areas A slit 12 is formed. The magnet 11 is magnetized and magnetized in a direction perpendicular to the q-axis (thickness direction of the plate-like magnet 11), and the adjacent magnet 11 has the same pole, and the pole of the motor is formed on the d-axis side.
[0015]
In the d-axis portion where the motor pole is formed, a reverse arc-shaped slit 12 is formed with the apex directed to the central hole 4 for shaft insertion . The slit 12 extends from one d-axis to the other d-axis. The magnetic flux (magnetic flux from the stator 1) is interposed substantially perpendicular to the magnetic flux to the magnetic flux (magnetic flux from the stator 1), and functions as a flux barrier. Secure enough roads. Accordingly, the d-axis and q-axis inductance ratio is increased (the salient pole ratio is increased), thereby increasing the reluctance torque.
[0016]
The slit 12 has a three-layer structure in the d-axis direction, but it may be at least one layer. In the stator 1, for example, the outer diameter side winding is the U phase, the inner diameter side winding is the W phase, and the intermediate winding is the V phase. Furthermore, although the 24-slot stator 1 is provided with three-phase (U-phase, V-phase, and W-phase) armature windings, the number of slots and the armature windings may be different.
[0017]
By the way, the magnet 11 embedded along the q-axis generates a pole (N-pole or S-pole) on the d-axis side, and this pole is alternately generated in the circumferential direction, so that magnet torque is generated. . The distance between the outer peripheral edge of the rotor 10 and the end of the magnet 11 is set to a value larger than the thickness t (for example, t to 3t), where t is the thickness of a core sheet 10a described later. Thereby, leakage of magnetic flux and short circuit of the magnet 11 can be prevented, that is, it contributes to improvement of the magnet torque, and there is no generation of burrs or the like when the core is manufactured by the automatic press described later, and the core is manufactured with high accuracy. Can do.
[0018]
The motor cost depends on the size of the magnet 11. Therefore, by reducing the amount of magnet 11 used, the cost can be reduced, while the magnetic path width from one q-axis to the other q-axis is increased, and a slit 12 is formed here to form a d-axis and q-axis. The inductance ratio can be increased. In this way, it is possible to compensate for the decrease in magnet torque due to the decrease in the amount of magnet 11 used with the reluctance torque. Further, as the magnet 11, a ferrite magnet or a rare earth magnet is used. In this case, the ferrite magnet is effective for reducing the cost, and the rare earth magnet is effective for increasing the torque.
[0019]
Further, in the manufacture of the rotor 10, a core lamination method (automatic lamination method) is adopted in which a magnetic press steel plate is punched out by automatic press using a core press die and is integrally formed in the die. As shown in FIGS. 2 and 3, in this pressing process, the core of the rotor 10 is punched. In the present invention, the central hole 4 for shaft insertion , the hole for embedding the magnet 11 and the hole for the slit 12 are simultaneously formed at that time. The core sheet 10a punched out is laminated.
[0020]
Then, the magnet 11 is embedded in the core hole of the rotor 10 obtained by automatically pressing and laminating by the IPM method. As described above, the magnet 11 is magnetized and magnetized in the direction perpendicular to the q axis so that the adjacent magnets 11 have the same polarity.
[0021]
In this way, the reluctance torque can be increased by forming the slit 12, the total torque can be improved by the magnet torque and the reluctance torque, and thus a high torque and high efficiency motor can be realized, and the cost and torque can be realized. In consideration of the above, an appropriate motor can be realized by selecting the amount (size) of the magnet used.
[0022]
FIG. 4 is a schematic plan view of a rotor for explaining another embodiment of the present invention. In the figure, the same parts as those in FIG. For the stator 1, see FIG. In this embodiment, a flux barrier 21 is formed at the end of the magnet 11 on the side of the center hole 4 in order to prevent short circuit and leakage of the magnetic flux at the end of the magnet 11 on the side of the center hole 4.
[0023]
The rotor 20 shown in FIG. 4 has a structure having a flux barrier 21 formed by a pair of elongated holes 21a and 21b extending in the direction of the adjacent magnet 11 from the end of the magnet 11 (end on the center hole 4 side). The distance between the magnet 11 and the elongated hole 21a, the distance between the magnet 11 and the elongated hole 21b, the distance between the elongated hole 21a and the elongated hole 21b, the distance between the center hole 4 and the elongated hole 21a, and the center hole 4 and the elongated hole 21b. Is set to be larger than the thickness t of the core sheet 10a. Thereby, short circuit and leakage of the magnetic flux of the magnet 11 can be prevented, and the magnet torque can be effectively generated. On the other hand, the occurrence of burrs or the like can be prevented at the time of manufacturing the core, and between the holes 21a and 21b. Becomes a bridging portion, and the core strength can be increased.
[0024]
5 and 6 are schematic plan views of a rotor for explaining a modified embodiment of the present invention. In the figure, the same or corresponding parts as those in FIG. For the stator 1, FIG. 1 was referred to. The rotor 20 shown in FIG. 5 passes a rivet 22 for caulking the core between the slit 12 and the center hole 4 on the d-axis, that is, between the adjacent magnets 11.
[0025]
In this case, the distance between the center hole 4 and the rivet 22 and the distance between the rivet 22 and the end of the magnet 11 are made larger than the thickness t of the core sheet 10a. Thereby, in manufacture of the rotor 20, generation | occurrence | production of the burr | flash etc. at the time of press work can be prevented, and a yield can be aimed at. As the material of the rivet 22, a magnetic material having a good magnetic permeability is used. Thereby, the influence on the magnetic flux from one q-axis to the other q-axis can be reduced, and the d-axis and q-axis inductance ratio can be increased.
[0026]
Further, the rotor 20 shown in FIG. 6 passes the rivet 23 on the d-axis between the outermost slit 12 and the outer periphery of the core. In this case, the distance between the outermost slit 12 and the rivet 23 and the distance between the outer periphery of the rotor 20 and the rivet 23 are made larger than the thickness t of the core sheet 10a for the same reason as described above. By the way, the holes through which the rivets 22 and 23 shown in FIG. 5 and FIG. That is, when the center hole 4, the hole of the magnet 11, the slit 12, and the hole of the flux barrier 21 are punched, the through holes of the rivet 22 or rivet 23 can be punched simultaneously.
[0027]
FIG. 7 is a schematic plan view of a rotor having a flux barrier different from the embodiment shown in FIGS. In addition, in the figure, the same code | symbol is attached | subjected to the part which is the same as FIG. 4 thru | or FIG. 6, and a corresponding part, and duplication description is abbreviate | omitted. The rotor 20 replaces the flux barrier 21 of the elongated holes 21a and 21b shown in FIGS. 4 to 6 with one flux barrier 24 in the center hole of the magnet 11 in order to prevent leakage of magnetic flux of the magnet 11 and short circuit. It is formed between the end portions on the 4 side.
[0028]
The above-described flux barriers 21 and 22 are linearly elongated holes, but may be curved holes. For example, the flux barriers 21 and 22 are formed as one reverse arc-shaped slit, and the center hole of the slit is formed. 4 side is made into the circular arc curve along the same center hole 4, and the core outer peripheral side of the slit is made into the reverse circular arc curve. Thereby, not only leakage of magnetic flux and short circuit prevention but also a magnetic flux path from one q-axis to the other q-axis can be secured.
[0029]
8 and 9 are schematic plan views of a rotor showing still another modification of the present invention. In the figure, the same parts as those in FIG. 3 and the parts regarded as the same as those in FIG. The rotor 10 shown in FIG. 8 includes a slit 25 having a bathtub-shaped cross section instead of the slit 12 shown in FIG. The sectional bathtub shape of the slit 25 refers to a shape along both sides and the top side except for the bottom side of the trapezoid.
[0030]
In this case, the bottom of the bathtub-shaped cross section is formed in a plurality of layers toward the central hole 4. This also secures a path for magnetic flux from the stator 1 (magnetic flux from one q-axis to the other q-axis), and can increase the d-axis and q-axis inductance ratio as described above.
[0031]
The rotor 10 shown in FIG. 9 includes a V-shaped slit 26 instead of the slit 12 shown in FIG. In this case, the V-shaped opening angle is an obtuse angle, and this apex angle is formed in a plurality of layers toward the central hole 4. As a result, a path for magnetic flux from the stator 1 (magnetic flux from one q-axis to the other q-axis) can be secured, and the d-axis and q-axis inductance ratio can be increased as described above.
[0032]
Although not shown in FIGS. 8 and 9, it is preferable to form the flux barrier 21 shown in FIG. 4 or the flux barrier 24 shown in FIG. The rivet for caulking the core is passed through the same position as the rivet 22 shown in FIG. 5, that is, between the center hole 4 and the slit 25 on the d-axis, or the rivet 23 shown in FIG. It is sufficient to pass between the outer periphery of the core and the slit 25 on the same position as in FIG.
[0033]
Furthermore, if the above-described rotors 10 and 20 are incorporated into a DC brushless motor, for example, if used as a compressor motor of an air conditioner, the operating efficiency of the air conditioner can be increased without increasing costs. Can do.
[0034]
【The invention's effect】
According to the present invention described above, the following effects are exhibited. In the present invention, since the slit for increasing the reluctance torque is formed in the rotor, the reluctance torque can be fully utilized, and a high torque and high efficiency motor can be realized by the reluctance torque and the magnet torque. In addition, there is an effect that an applicable motor can be realized by selecting the usage (size) of the magnet in consideration of cost and torque.
[0035]
In the present invention, the slit for increasing the reluctance torque in the rotor has a multi-layer structure in the d-axis direction, so that a path of magnetic flux from one q-axis to the other q-axis is secured, while The flux barrier effect is effectively exerted on the magnetic flux to the d-axis, and the reluctance torque can be further increased. As a result, a high torque and high efficiency motor can be obtained.
[0036]
In the present invention, a flux barrier is formed at the center hole side end of the magnet embedded in the rotor, and this flux barrier is extended to the center hole side end of the adjacent magnet. There is an effect that leakage can be prevented and magnet torque can be generated effectively.
[0037]
In the present invention, since the flux barrier formed on the rotor is divided into two at the intermediate portion to form a pair of flux barriers, a bridge portion is formed between the pair of holes to increase the core strength. There is an effect that can be done.
[0038]
In the present invention, a rivet for caulking the core is passed on the d-axis, and this rivet is made of a magnetic material. Therefore, the strength of the rotor is improved, and the magnetic flux from one q-axis to the other q-axis is affected. This can be done without having to reduce the d-axis and q-axis inductance ratio.
[0039]
In the present invention, when a rotor is obtained by punching an electromagnetic steel sheet with an automatic press and automatically laminating it in a mold, a buried hole of a magnet, a hole of a slit, a hole of a rivet and a hole of a flux barrier are punched. Since the gap between the holes and between the holes and the outer periphery of the core is at least larger than the thickness of the core sheet, the conventional press technology can be used, that is, it can be realized without an increase in manufacturing cost. There is an effect that it is possible to prevent the occurrence of burrs or the like during the manufacture of the core, increase the yield of the core manufacture, and consequently reduce the manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a permanent magnet motor showing an embodiment of the present invention.
FIG. 2 is a schematic sectional side view of a rotor for explaining the permanent magnet motor shown in FIG. 1;
FIG. 3 is a schematic plan view of a rotor for explaining the permanent magnet motor shown in FIG. 1;
4 is a schematic plan view for explaining another embodiment of the rotor shown in FIG. 3; FIG.
FIG. 5 is a schematic plan view for explaining another embodiment of the rotor shown in FIG. 4;
6 is a schematic plan view for explaining a modified example of the rotor shown in FIG. 5;
7 is a schematic plan view for explaining a modification of the rotor shown in FIG. 4; FIG.
FIG. 8 is a schematic plan view of a rotor showing another modified embodiment of the present invention.
FIG. 9 is a schematic plan view of a rotor showing another embodiment of the present invention.
FIG. 10 is a schematic plan view of a conventional permanent magnet motor.
[Explanation of symbols]
1 Stator 4 Center hole (for shaft)
10, 20 Rotor 10a Core sheet 11 Magnet (plate-shaped permanent magnet)
12 Slit (arc shape)
21, 24 Flux barrier 21a, 21b Hole (flux barrier)
22, 23 Rivet 25 Slit (cross-sectional bathtub shape)
26 Slit (V-shaped)
t Core sheet thickness

Claims (7)

The permanent magnet motor having a rotor inside the stator for generating a rotating magnetic field, the rotor, the plate-like magnet along the q-axis, and only a few minutes poles along the outer circumference of the rotor is buried at regular intervals, the magnetization of the magnet and the direction perpendicular to the q-axis, and the opposite pole of the magnet adjacent to the same polarity to form the equivalent polar to the d-axis portion, the d-axis portion A slit that secures a magnetic path (magnetic flux path) from one q-axis to the other q-axis is formed, and the d-axis and q-axis inductance ratio is increased by the slit. Magnet motor. Before kissing lit is a cross-sectional circular arc shape, cross-sectional bathtub shape or V-shape, the claims are formed in the multilayer their central portions at equal intervals in the d-axis direction while facing the center hole side shaft 1. The permanent magnet motor according to 1. Before the end of the shaft insertion central hole side Kemah Gunetto to form a flux barrier, the flux barrier claim 1 as over the end of the shaft inserting the center hole side of said magnet adjacent or 2. The permanent magnet motor according to 2. Before notated parallax barrier is a permanent magnet motor according to claim 3, divided into two in the middle section comprising a pair of flux barriers. Between or between the slit and the flux barrier between the front kissing lit and the shaft insertion central hole made through the rivet for the core caulking on the d-axis, according to claim 1, 2 or 3 said rivet has a magnetic material permanent magnet electric motor according to. Between or between the slit and the flux barrier between the core outer circumference of the front kiss lit and the rotor, through the rivet of core caulking on the d-axis, claim 1 of the rivet and a magnetic material or permanent magnet electric motor according to 3. The rotor with punching a core sheet made of an electromagnetic steel plate in an automatic press, a core formed by automatically stacking in a mold, embedding hole of the magnet when the automatic pressing, the slit holes, hole of the rivet and punching a hole in the flux barriers, and, and between the core outer periphery thereof hole and the rotor of these holes, according to at least any one of said core claims 1 larger the than the thickness of the sheet 6 Permanent magnet motor.

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