JP3739890B2 - Permanent magnet type motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet type motor used for a motor for driving a compressor of an air conditioner or a refrigerator.
[0002]
[Prior art]
2. Description of the Related Art In recent years, permanent magnet motors that are easy to control the rotation speed and have high motor efficiency are generally used in compressor motors of air conditioners and refrigerators. FIG. 8 illustrates a permanent magnet type motor that is currently most commonly used.
[0003]
FIG. 8 shows a cross-sectional view of the rotor 1 and the stator 2 of the permanent magnet type motor. Reference numeral 3 denotes a magnet insertion hole provided in the rotor core, into which the permanent magnet 4 is inserted. Further, in order to prevent leakage of magnetic flux to an adjacent magnet, a noble hole 5 having a large magnetic resistance is provided between the permanent magnet and the adjacent permanent magnet.
[0004]
With the shape as described above, an inductance difference between the d-axis and the q-axis is generated, and reluctance torque is generated in addition to torque (magnet torque) generated by the magnetic flux of the permanent magnet, thereby improving the total torque.
[0005]
FIG. 9 is a cross sectional view of a permanent magnet type motor disclosed in, for example, Japanese Patent Laid-Open No. 6-189482. In this example, in addition to the structure of FIG. 8, the slits 7 are uniformly arranged on the outer peripheral side of the magnet insertion hole of the rotor core.
[0006]
In this configuration, d-axis as those of the structure of FIG. 8, since not take a large inductance difference of the q-axis, although the reluctance torque is not available, by providing the slit, Electric child reaction by the stator current is generated The permanent magnet magnetic flux is uniformly supplied from the rotor surface to the stator. That is, the magnetic flux densities of the stator teeth 6a to 6e are almost the same, and a part of the stator teeth (for example, 6a and 6b) does not cause magnetic saturation and does not deteriorate the motor characteristics.
[0007]
FIG. 10 is a cross-sectional view of a permanent magnet type motor commercialized as a compressor motor for an air conditioner. In this example, instead of having no slit in the rotor core, a notch 14 for cutting the outer periphery of the rotor core of the rotor rotation direction side iron core is provided.
[0008]
This shape causes an inductance difference between the d-axis and the q-axis, and reluctance torque can be used. In addition, the Electric child reaction, the permanent magnet flux to prevent the bend in the rotational direction, to increase the air gap in the rotational direction side is provided with a notch 14 to increase the magnetic resistance. As a result, the magnetic flux density of the stator teeth 6a to 6e becomes uniform, a portion of the stator teeth (for example, 6a and 6b) does not cause magnetic saturation, and the motor characteristics are not deteriorated.
[0009]
[Problems to be solved by the invention]
However, the permanent magnet type motor as described above has the following problems.
[0010]
Those in FIG. 8, for Electric child reaction by the stator current, when the motor operation, the permanent magnet flux is significantly bent in the rotor rotation direction, of the stator teeth facing the permanent magnet (6e from 6a) The magnetic flux density of the stator teeth (6a, 6b) that opposes the rotor rotation direction side iron core is abnormally higher than other stator tooth magnetic flux densities. In a high motor, saturation of magnetic flux occurs, causing deterioration of motor characteristics (decrease in motor efficiency and increase in noise).
[0011]
Since the reluctance torque cannot be used in the case of FIG. 9, the motor efficiency is deteriorated compared to the structure in which the reluctance torque can be used.
[0012]
In FIG. 10, the average gap length is increased due to the notch, the magnetic resistance is increased, and the motor efficiency is lowered.
[0013]
This invention, in addition to consideration of the arrangement and shape of the slit provided in the magnet insertion hole in the rotor core, magnetic saturation of the stator teeth facing the rotor rotational direction core by Electric child reaction does not occur In addition to preventing the reduction in motor efficiency accompanying this, the reluctance torque can be used, so that the necessary torque can be generated with a small amount of current, and the motor efficiency can be improved by the amount of decrease in the necessary current. A magnet type motor is to be obtained.
[0014]
[Means for Solving the Problems]
In the permanent magnet type motor according to the first aspect of the present invention, a cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, and the rotor core are provided. In a permanent magnet type motor comprising a plurality of magnet insertion holes and a permanent magnet accommodated in the magnet insertion holes, and having a slit provided in an outer peripheral side iron core portion of the magnet insertion hole, the slit is formed as a rotor magnetic pole. In addition to being provided only on the rotor rotation direction side iron core from the center line , the opening of the slit is provided only on the gap side existing between the stator and the rotor .
[0015]
In the permanent magnet type motor according to the second invention, a cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, and the rotor core are provided. In a permanent magnet type motor having a plurality of magnet insertion holes and a permanent magnet accommodated in the magnet insertion holes, and having a slit provided in an outer peripheral side iron core part of the magnet insertion hole, the slit is arranged at the rotor magnetic pole center. Are provided on the rotor rotation direction side iron core from the line and the rotor magnetic pole center line from the rotor counter rotation direction side iron core, respectively, and the number of those located on the rotor rotation direction side iron core from the rotor magnetic pole center line of the slit is More than the number of the cores located on the rotor counter-rotation direction side iron core than the rotor magnetic pole center line.
[0016]
In the permanent magnet type motor according to the third invention, a cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, and the rotor core are provided. In a permanent magnet type motor having a plurality of magnet insertion holes and a permanent magnet accommodated in the magnet insertion holes and having a slit provided in an outer peripheral side iron core part of the magnet insertion hole, the rotor magnetic pole center of the slit The width of the core located on the rotor rotational direction side core from the line is made wider than the width of the core located on the rotor counter-rotation direction side core from the rotor magnetic pole center line.
[0017]
In the permanent magnet type motor according to the fourth invention, a cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, and the rotor core are provided. In a permanent magnet type motor having a plurality of magnet insertion holes and a permanent magnet accommodated in the magnet insertion holes and having a slit provided in an outer peripheral side iron core part of the magnet insertion hole, the rotor magnetic pole center of the slit The length of the core positioned on the rotor rotation direction side iron core from the line is made longer than that of the rotor magnetic pole center line positioned on the rotor counter rotation direction side iron core.
[0018]
In the permanent magnet type motor according to the fifth aspect of the invention, the opening of the slit is provided only on the permanent magnet side.
[0019]
In the permanent magnet type motor according to the sixth aspect of the present invention, the opening of the slit is provided only on the side of the gap existing between the stator and the rotor.
[0020]
In the permanent magnet type motor according to a seventh aspect of the present invention, the slit does not have an opening side on either the permanent magnet side or the gap side.
[0021]
In the permanent magnet type motor according to the eighth aspect of the invention, the slit is filled with a non-magnetic material.
[0022]
In these inventions, the number of slits located in the rotor rotation direction side iron core from the rotor magnetic pole center line is larger than the number of slits in the rotor counter rotation direction side iron core, or the shape is devised, so that the q axis decrease in the rotor rotational direction core inductance, it increases the rotor opposite to the rotary direction core (the q-axis magnetic resistance increases in the rotor rotational direction core, small in the rotor counter-rotation direction side core) since, electric Magnetic saturation of the stator teeth facing the rotor core in the rotor rotation direction due to the child reaction does not occur, while reluctance torque can be used.
Moreover, since no notch is provided in the outer periphery of the rotor core, the motor efficiency does not decrease due to the increase in the average gap length.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a motor showing Embodiment 1 of the present invention, and the same parts as those in the conventional apparatus are denoted by the same reference numerals (the following embodiments are also the same).
In FIG. 1, reference numeral 1 denotes a rotor, which includes a rotor core 8, a magnet insertion hole 3, a permanent magnet 4, and a slit 7.
The iron core 8 is laminated with a stamped thin steel plate, and the permanent magnets 4 are arranged so that N poles and S poles are alternated.
Reference numeral 2 denotes a stator, which is composed of a stator iron core 9 and a stator winding 10, and the stator iron core 9 is laminated with a pressed thin steel plate in the same manner as the rotor iron core. Of the stator cores, 6a to 6e are referred to as stator teeth.
[0024]
The generated torque of the motor is roughly expressed by the following equation.
T = Tmagnet + Treluctance
= K · (BdI · n · L) + Treluctance
Where T is the motor torque, Tmagnet is the magnet torque, Treluctance is the reluctance torque, K is a constant, Bd is the d-axis magnetic flux density (permanent magnet magnetic flux density), I is the winding current, n is the winding number, and L is the iron core. Thickness.
[0025]
In this embodiment, since the slit 7 is provided, the armature reaction due to the stator current is less likely to occur, and part of the stator teeth (particularly the stator teeth 6a and 6b) due to the armature reaction are abnormally magnetic fluxes. The saturation phenomenon of increasing density does not occur, and there is no loss associated with it, resulting in an efficient motor.
Further, since the slits are elongated along the d-axis so as not to interfere with the d-axis magnetic flux, the d-axis magnetic flux density Bd does not decrease and the magnet torque does not decrease.
Further, since the slit 7 is provided only in the rotor rotation direction side iron core 12 with respect to the rotor magnetic pole center line 11, the rotor non-rotation direction side iron core 13 having no slit easily flows q-axis magnetic flux and q-axis inductance. The difference in d-axis inductance is large, and reluctance torque can be used.
[0026]
FIG. 11 and FIG. 12 show the results of performing electromagnetic field analysis by CAE for this embodiment.
FIG. 11 shows that the magnetic flux saturation of the stator teeth is alleviated by adopting the structure of this embodiment.
From FIG. 12, it can be seen that the motor generated torque is increased by adopting the structure of this embodiment.
That is, even if the winding current I is small, the same torque can be generated, the loss due to the winding current is reduced, and the motor efficiency is improved.
[0027]
Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a cross-sectional view of a motor showing an embodiment of the present invention.
The second embodiment is characterized in that the number of slits 7 located on the rotor rotation direction side iron core 12 from the rotor magnetic pole center line 11 is larger than the number of slits 7 located on the rotor rotation direction side iron core 13. It is what.
[0028]
In the first embodiment, the slit 7 is provided only in the rotor rotation direction side iron core 12, whereas in the second embodiment, the slit 7 is provided also in the rotor counter rotation direction side iron core 13. The second embodiment is effective for a motor in which the reluctance torque is smaller than in the first embodiment but the saturation of the magnetic flux is small and the performance deterioration due to the saturation of the magnetic flux is larger than the torque generated by the motor.
[0029]
Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 3 is a cross-sectional view of a motor showing an embodiment of the present invention. In this embodiment, the width of the slit 7 positioned on the rotor rotation direction side iron core 12 from the rotor magnetic pole center line 11 is the width of the slit 7 positioned on the rotor counter rotation direction side iron core 13 from the rotor magnetic pole center line 11. It is characterized by being thicker.
[0030]
In the third embodiment, the q-axis magnetic flux does not easily flow through the rotor rotating side iron core having a thick slit, but some q-axis magnetic flux flows through the rotor non-rotating direction side iron core 13 having a narrow slit to generate reluctance torque. . Therefore, the same effect as in the first embodiment can be obtained.
[0031]
Further, since the slits 7 are provided in both the rotor rotation direction side iron core 12 and the rotor non-rotation direction side iron core 13 from the rotor magnetic pole center line 11, the balance when pressing the iron core is good and the slits are uneven. The twist of the iron core at the time of punching does not occur like when placed.
[0032]
Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a cross-sectional view of a motor showing an embodiment of the present invention. In the fourth embodiment, the length of the slit 7 positioned on the rotor rotation direction side iron core 12 from the rotor magnetic pole center line 11 is positioned on the rotor counter rotation direction side iron core 13 from the rotor magnetic pole center line 11. It is characterized by being longer than the length of the object.
[0033]
In the fourth embodiment, q-axis magnetic flux does not easily flow in the rotor rotation direction side iron core 12 with a long slit, but some q-axis magnetic flux flows in the rotor non-rotation direction side iron core 13 with a short slit and reluctance torque is generated. To do. Therefore, the same effect as in the first embodiment can be obtained.
[0034]
In addition, since the slits 7 are provided on both the rotor rotation direction side iron core 12 and the rotor non-rotation direction side iron core 13 from the rotor magnetic pole center line, the balance is good when the iron core is pressed and the slits are unevenly arranged. The iron core is not twisted at the time of punching.
[0035]
Embodiment 5. FIG.
Next, a fifth embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a cross-sectional view of a motor showing an embodiment of the present invention.
In the fifth embodiment, since the opening of the slit 7 is provided only on the permanent magnet side, there is little frictional resistance with the medium on the outer periphery of the rotor, and the efficiency reduction due to the frictional resistance with the medium is prevented. be able to.
In addition, a jig such as a gap gauge is used to uniformly create a gap existing between the stator and the rotor when the motor is assembled. However, this jig gets caught in the slit of the rotor, which deteriorates productivity. Disappears.
[0036]
Embodiment 6 FIG.
Next, a sixth embodiment of the invention will be described.
FIG. 6 is a cross-sectional view of a motor showing an embodiment of the present invention.
In the sixth embodiment, the opening of the slit 7 is provided only on the gap side existing between the stator and the rotor.
In this configuration, since asked the slit closer to the stator, Electric child reaction by the stator current can be reduced relative to those not slit provided on the gap side, the saturation of the stator teeth flux For this, it becomes more effective.
[0037]
Embodiment 7 FIG.
Next, a seventh embodiment of the present invention will be described.
FIG. 7 is a cross-sectional view of a motor showing an embodiment of the present invention. The seventh embodiment is characterized in that the opening of the slit 7 is not provided on either the permanent magnet side or the gap side, and the mechanical strength against the centrifugal force of the rotor core can be improved.
[0038]
Embodiment 8 FIG.
Next, an eighth embodiment of the present invention will be described.
FIG. 8 is a cross-sectional view of a motor showing one embodiment of the present invention.
The eighth embodiment is characterized in that the slit 7 is filled with a nonmagnetic material, and the mechanical strength of the rotor core can be improved.
On the other hand, since the nonmagnetic material has substantially the same magnetic permeability as air, an electrically equivalent effect can be obtained with respect to those in which nothing is put into the slit.
[0039]
The filling of the non-magnetic material of the present invention can be applied to all the shapes of the first to seventh embodiments, and simultaneously with the improvement of the mechanical strength, the first to seventh embodiments. The effect of can be obtained as it is.
[0040]
【The invention's effect】
According to the invention, the arrangement of the slits located on the rotor rotational direction core than the rotor magnetic pole center line, since as devising the shape, faces the rotor rotational direction core by Electric child reaction Magnetic saturation of the stator teeth does not occur, and it is possible to prevent a reduction in motor efficiency associated with this, and the reluctance torque can be used effectively, so the required torque can be generated with a small amount of current and the required current is reduced Therefore, the motor efficiency can be improved.
[0041]
According to the first invention, the slit provided in the outer core portion of the magnet insertion hole in the rotor core is provided only in the rotor rotation direction side iron core from the rotor magnetic pole center line , and the opening of the slit is fixed. because provided only on the gap side that exists between the child and the rotor, electric child reaction magnetic saturation of the stator teeth facing the rotor rotational direction core by is not generated, the motor efficiency due to this Since the reluctance torque can be used effectively, the required torque can be generated with a small amount of current, and the motor efficiency is improved by the reduction of the required current , and it is close to the stator. By moving the slit toward the side, the armature reaction due to the stator current can be suppressed to a small value, which is more effective for the saturation of the stator tooth magnetic flux.
[0042]
According to the second aspect of the present invention, the slit provided in the outer core portion of the magnet insertion hole in the rotor core has the rotor rotation direction side iron core and the rotor magnetic pole center line from the rotor magnetic pole center line, and the rotor counter-rotation direction. And the number of those located on the rotor core side of the rotor from the rotor magnetic pole center line of the slit, and the number of cores located on the rotor counter-rotation side iron core from the rotor magnetic pole center line. since many were, the stator magnetic saturation of the teeth facing the rotor rotational direction core by electric child reaction does not occur, it is possible to prevent a decrease in motor efficiency due to this, the reluctance torque can be effectively utilized this makes it possible to generate the required torque with a small current, amount that needs current decreases, the improvement of the motor efficiency is achieved, and the slits in the rotor opposite to the rotary direction core The reluctance torque is somewhat smaller that of the magnetic flux saturation is small, is effective against motor deterioration in performance due to saturation of the magnetic flux is greater than the motor torque.
[0043]
According to the third aspect of the invention, the width of the slit located in the rotor rotation direction side iron core from the rotor magnetic pole center line of the slit provided in the outer peripheral side iron core portion of the magnet insertion hole in the rotor core is set to the rotor magnetic pole center line. since thicker than the width of those located more rotor counter-rotation direction side core, electric child reaction magnetic saturation of stator teeth facing the rotor rotational direction core by is not generated, the motor efficiency due to this Since the reduction can be prevented and the reluctance torque can be used effectively, the required torque can be generated with a small current, and the motor efficiency can be improved by the reduction of the required current.
[0044]
According to the fourth invention, the length of the slit located on the rotor rotation direction side iron core from the rotor magnetic pole center line of the slit provided in the outer peripheral side iron core portion of the magnet insertion hole in the rotor iron core is set to the rotor magnetic pole center. magnetic saturation of the stator teeth facing the rotor rotational direction core by longer the electric child counteract the length of those located on the rotor opposite to the rotary direction core core from the line is not generated, the motor efficiency due to this While the reduction can be prevented and the reluctance torque can be used effectively, the required torque can be generated with a small current, and the motor efficiency can be improved by the reduction of the required current.
[0045]
According to the fifth invention, since the opening of the slit is provided only on the permanent magnet side, the frictional resistance between the rotor and the outer periphery of the rotor is small, and the efficiency reduction due to the frictional resistance with the medium is prevented. In addition, a jig such as a gap gauge is used to uniformly create a gap existing between the stator and the rotor at the time of motor assembly. However, this jig gets caught in the slit of the rotor, resulting in poor productivity. It is possible to eliminate the problem of doing.
[0046]
According to the sixth invention, since the opening of the slit is provided only on the gap side existing between the stator and the rotor, no armature reaction due to the stator current is provided on the gap side. It can be kept small with respect to the object, and is a more effective measure against the saturation of the stator tooth magnetic flux.
[0047]
According to the seventh invention, since the slit does not have an opening side on either the permanent magnet side or the gap side, the mechanical strength against the centrifugal force or the like of the rotor core can be improved. It is.
[0048]
According to the eighth invention, since the slit is filled with a non-magnetic material, the mechanical strength of the rotor core can be improved, and an electrically equivalent effect can be obtained.
[Brief description of the drawings]
FIG. 1 is a transverse sectional view of a permanent magnet type motor showing Embodiments 1 and 7 of the present invention.
FIG. 2 is a cross-sectional view of a permanent magnet type motor showing Embodiment 2 of the present invention.
FIG. 3 is a cross-sectional view of a permanent magnet type motor showing Embodiment 3 of the present invention.
FIG. 4 is a transverse sectional view of a permanent magnet type motor showing Embodiment 4 of the present invention.
FIG. 5 is a cross sectional view of a permanent magnet type motor showing Embodiment 5 of the present invention.
FIG. 6 is a cross-sectional view of a permanent magnet motor showing Embodiment 6 of the present invention.
FIG. 7 is a transverse sectional view of a permanent magnet motor showing Embodiment 8 of the present invention.
FIG. 8 is a cross-sectional view of a permanent magnet type motor showing a first conventional example.
FIG. 9 is a cross-sectional view of a permanent magnet type motor showing a second conventional example.
FIG. 10 is a cross-sectional view of a permanent magnet motor showing a third conventional example.
FIG. 11 is a diagram showing a CAE electromagnetic field analysis result 1;
12 is a diagram showing CAE electromagnetic field analysis result 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor, 2 Stator, 3 Magnet insertion hole, 4 Permanent magnet, 5 Through-hole, 6a, 6b, 6c, 6d, 6e Stator tooth part, 7 Slit, 8 Rotor core, 9 Stator core, 10 Fixation Child winding, 11 Rotor magnetic pole center line, 12 Rotor rotation direction side iron core, 13 Rotor counter rotation direction side iron core.

Claims (8)

A cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, a plurality of magnet insertion holes provided in the rotor core, and accommodated in the magnet insertion hole A permanent magnet type motor having a slit provided in the outer core portion of the magnet insertion hole, and the slit is provided only in the rotor rotation direction side core from the rotor magnetic pole center line. The permanent magnet type motor is characterized in that the opening of the slit is provided only on the side of the gap existing between the stator and the rotor . A cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, a plurality of magnet insertion holes provided in the rotor core, and accommodated in the magnet insertion hole A permanent magnet type motor having a slit provided in an outer peripheral side iron core portion of the magnet insertion hole, wherein the slit is arranged on the rotor rotation direction side iron core and the rotor magnetic pole center from the rotor magnetic pole center line. The number of the slits located on the rotor rotation side iron core from the rotor magnetic pole center line of the slit is set on the rotor counter rotation direction side from the rotor magnetic pole center line. A permanent magnet type motor characterized by having more than the number of those located in the iron core.   A cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, a plurality of magnet insertion holes provided in the rotor core, and accommodated in the magnet insertion hole A permanent magnet type motor having a slit provided in an outer peripheral side core portion of the magnet insertion hole, and a width of the slit located on the rotor rotational direction side core from the rotor magnetic pole center line of the slit Is made thicker than the width of the core located on the side opposite to the rotor counter-rotation direction from the rotor magnetic pole center line.   A cylindrical stator core around which a coil is wound, a rotor core disposed inside the stator core, a plurality of magnet insertion holes provided in the rotor core, and accommodated in the magnet insertion hole A permanent magnet type motor having a slit provided in an outer peripheral side core portion of the magnet insertion hole, the length of the slit being located on the rotor rotation side iron core from the rotor magnetic pole center line of the slit A permanent magnet motor characterized in that the length of the core located on the rotor counter-rotation direction side iron core is longer than the rotor magnetic pole center line. The permanent magnet type motor according to any one of claims 2 to 4, wherein the slit opening is provided only on the permanent magnet side. The permanent magnet type motor according to any one of claims 2 to 4, wherein the opening of the slit is provided only on the side of a gap existing between the stator and the rotor. The permanent magnet type motor according to any one of claims 2 to 4, wherein the slit does not have an opening side on either the permanent magnet side or the gap side.   The permanent magnet type motor according to claim 1, wherein the slit is filled with a nonmagnetic material.

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