JPH11178255A - Permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent magnet motor, wherein a phenomenon of the detection of the position of a rotor is made difficult due to the reaction of an armature not occurring and the efficiency of the motor can be improved by making good use of reluctance torque. SOLUTION: This permanent magnet motor is provided with a stator 2 formed by winding coils around a cylindrical stator core 9, a rotor 1 which is placed inside the stator 2 and has a rotor core 8, a plurality of magnet insertion holes 3 drilled in the rotor core 8, and permanent magnets 4 inserted into the magnet insertion holes 3, and slits 7 which are formed in the rotor 1 and on the peripheral core portions of the magnet insertion holes 3 on the side of reverse rotation of the rotor of the center lines 11 of the rotor magnetic poles in the direction of the center lines 11 of the rotor magnetic poles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field 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]

2. Description of the Related Art FIG. 5 shows that the applicant filed Japanese Patent Application No.
1 is a cross-sectional view of a permanent magnet type motor proposed in JP-A-088409. In the figure, 1 is a rotor, 2 is a stator, 3 is a magnet insertion hole provided in a rotor core, and a permanent magnet 4 is inserted into the magnet insertion hole 3. Between the adjacent permanent magnets 4, a through hole 5 having a large magnetic resistance is provided in order to prevent leakage of magnetic flux. 6a, 6b, 6c, 6
d and 6e are stator teeth portions. In addition, a slit 7 is arranged in the rotor rotation direction side core 13 on the rotor rotation direction side of the rotor magnetic pole center line 11 of the magnet insertion hole outer periphery side iron core. The slit 7 is not provided in the rotor core 12 on the rotor anti-rotation direction side of the rotor magnetic pole center line 11 with respect to the rotor magnetic pole center line 11 of the magnet insertion hole outer peripheral core.

In the above-described configuration, the rotor core 1 in the rotor rotation direction is
Since the slit 7 is provided in the armature 3, the armature reaction due to the stator current hardly occurs, and a part of the stator teeth (particularly, the stator teeth 6d and 6e) due to the armature reaction has an abnormally high magnetic flux density. A motor with high efficiency without a saturation phenomenon and no accompanying loss is obtained.

Since the slits 7 are elongated along the d-axis so as not to hinder 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 core 13 with respect to the rotor magnetic pole center line 11, the rotor anti-rotation side core 12 having no slit is easy to flow q-axis magnetic flux and q-axis. The difference between the inductance and the d-axis inductance is large, and the reluctance torque can be used.

Conventional example 2. FIG. 6 shows, for example,
1 is a cross-sectional view of a permanent magnet type motor disclosed in Japanese Patent No. 9481. In this example, in addition to the structure shown in FIG. 5, a slit 7 is disposed on the outer peripheral side of the magnet insertion hole of the rotor core so that the slit 7 is wider in the rear than in the rotational direction.

In the configuration shown in FIG. 6, since the inductance difference between the d-axis and the q-axis cannot be made large unlike the configuration shown in FIG. 5, reluctance torque cannot be used. The reaction is less likely to occur, and the permanent magnet magnetic flux is uniformly supplied to the stator from the rotor surface.

That is, the magnetic flux densities of the stator teeth 6a to 6e are all substantially the same, and a part (for example, 6d, 6e) of the stator teeth does not cause magnetic saturation and does not deteriorate the motor characteristics. Further, by making the slit 7 rearward in the rotation direction thicker than the front one in the rotation direction, in a motor that detects and controls the rotational position based on the induced voltage, the commutation spike included in the induced voltage is reduced. The problem that the time becomes longer and the position detection becomes difficult has been improved.

[0009]

The above-described permanent magnet type motor has the following problems. (1) In the permanent magnet type motor of Conventional Example 1 (FIG. 5), the armature reaction generated in the rotor anti-rotation direction side core 13 disturbs the induced voltage waveform generated in the stator winding. In a permanent magnet type motor that performs detection and control, there has been a phenomenon that it is difficult to detect the position of the rotor. (2) In the permanent magnet type motor of Conventional Example 2 (FIG. 6), although the position detection of the rotor is improved, the slit 7 is formed on the entire outer peripheral side of the magnet insertion hole. The reluctance torque could not be used, and the motor efficiency was poor.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and does not cause a phenomenon that it is difficult to detect the position of the rotor due to the armature reaction. Further, the improvement of the motor efficiency by utilizing the reluctance torque is achieved. It is an object of the present invention to provide a permanent magnet type motor that can be achieved.

[0011]

According to the present invention, there is provided a permanent magnet type motor comprising: a stator having a coil wound around a cylindrical stator core; a rotor provided inside the stator; A plurality of magnet insertion holes drilled in the rotor core,
A rotor having a permanent magnet inserted into the magnet insertion hole, and a rotor magnetic pole center provided on the rotor, the rotor magnetic pole center being on the rotor anti-rotation side with respect to the rotor magnetic pole center line of the outer core of the magnet insertion hole. And a slit formed in a linear direction.

The slit has a gap-side opening that opens to the gap side that exists between the stator and the rotor.

The slit is provided with a permanent magnet side opening that opens to the permanent magnet side.

[0014] Further, a non-magnetic filler filled in the slit is provided.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG.
BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows an example of embodiment of this invention, and is a cross-sectional view of a permanent magnet type motor. The same parts as those of the conventional device are denoted by the same reference numerals (the same applies to the following embodiments). In the figure, 1
Denotes a rotor, which includes a rotor core 8, a magnet insertion hole 3, a permanent magnet 4, and a slit 7. The rotor core 8
Are laminated by a pressed 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, a stator core 9, a stator winding 10
And the stator core 9 is similar to the rotor core 8,
It is laminated with press-cut thin steel plates. The stator cores 6a to 6e are referred to as stator teeth.

The generated torque of the permanent magnet type motor is approximately expressed by the following equation. T = Tmagnet + Treluctance = k · (Bd ■ I · n · L) + Treluctance where T is motor generated torque, Tmagnet is magnet torque, Reluctance is reluctance torque, K is a constant, and Bd is d-axis magnetic flux density (permanent magnet magnetic flux density). , I is the winding current, n is the number of winding turns, and L is the core thickness.

In the present embodiment, since the slit 7 is provided only in the iron core 12 on the side opposite to the rotor in the direction of rotation with respect to the center line 11 of the rotor magnetic pole, the configuration of the prior arts 1 and 2 is less than that of the conventional example. Part of stator teeth (particularly, stator teeth 6d, 6d
e) It is difficult to improve the saturation phenomenon in which the magnetic flux density becomes abnormally high. However, in the motor that detects and controls the rotational position by the induced voltage, the induced voltage waveform is improved as compared with the motor having the structure of the conventional example 1. This improves the position detection accuracy. This position detectability has been confirmed by experiments.

In addition, the rotor core 13 in the rotor rotation direction where the slit 7 is not inserted has a higher magnetic flux than the one shown in FIG. The torque can be increased, and the operating current can be reduced accordingly, and a highly efficient motor can be obtained.

Embodiment 2 Hereinafter, another example of the embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a view showing another example of the embodiment of the present invention, and is a cross-sectional view of a permanent magnet type motor. In the present embodiment, a gap-side opening is provided in which the slit 7 is opened to the gap existing between the stator 2 and the rotor 1. According to this configuration, since the slit is shifted toward the side close to the stator 2, the armature reaction due to the stator current can be made smaller than that in which the slit 7 is not shifted to the gap side, and the stator tooth magnetic flux can be reduced. It is more effective against saturation.

Embodiment 3 Hereinafter, another example of the embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a view showing another example of the embodiment of the present invention, and is a cross-sectional view of a permanent magnet type motor. In the present embodiment, a permanent magnet side opening in which the slit 7 is opened on the permanent magnet side is provided.
The frictional resistance between the rotor and the medium at the outer peripheral portion is small, so that it is possible to prevent a decrease in efficiency due to the frictional resistance with the medium. Further, a jig such as a gap gauge is used to uniformly remove a gap existing between the stator 2 and the rotor 1 at the time of assembling the motor. The problem of getting worse is gone. Also,
By opening the slit 7 on the permanent magnet side, the effect of shielding the stator magnetic flux can be enhanced.

Embodiment 4 FIG. Hereinafter, another example of the embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a view showing another example of the embodiment of the present invention, and is a cross-sectional view of a permanent magnet type motor. The present embodiment is characterized in that the slit 7 is filled with the non-magnetic filler material 14, and the mechanical strength of the rotor core 8 can be improved. On the other hand, since the non-magnetic filler 14 has substantially the same magnetic permeability as air, it is possible to obtain an electrically equivalent effect to the one in which nothing is inserted in the slit 7.

The non-magnetic filler 14 of the present embodiment
Can be applied to all of the first to third embodiments, and the effects of the first to third embodiments can be obtained as they are while improving the mechanical strength.

[0023]

According to the present invention, there is provided a permanent magnet type motor having a stator in which a coil is wound around a cylindrical stator core, a rotor core provided inside the stator, and a rotor core; A rotor having a plurality of magnet insertion holes drilled in the magnet insertion hole and a permanent magnet inserted in the magnet insertion hole, and a rotor magnetic pole center line of an outer peripheral iron core portion of the magnet insertion hole provided in the rotor. Since the rotor is provided with a slit formed in the direction of the center line of the rotor magnetic pole on the side opposite to the rotor in the rotation direction, a phenomenon that the detection of the rotor position becomes difficult due to the armature reaction does not occur. Further, since the reluctance torque can be used, the required torque can be generated with a small current, and the motor efficiency can be improved by the reduced required current.

Further, the slit has a gap side opening which opens on the gap side existing between the stator and the rotor, so that the slits are brought closer to the gap side due to the armature reaction caused by the stator current. Can be smaller than none
It is more effective against the saturation of the stator tooth magnetic flux.

Further, the effect of shielding the stator magnetic flux can be enhanced by providing the slit with the permanent magnet side opening that opens to the permanent magnet side.

In addition, the provision of the non-magnetic filler filled in the slit can improve the mechanical strength of the rotor core.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a permanent magnet type motor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a permanent magnet type motor according to a second embodiment of the present invention.

FIG. 3 is a transverse sectional view of a permanent magnet type motor according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a permanent magnet type motor according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional permanent magnet type motor.

FIG. 6 is a cross-sectional view of another conventional permanent magnet type motor.

[Explanation of symbols]

1 rotor, 2 stators, 3 magnet insertion holes, 4 permanent magnets, 5 through holes, 6a, 6b, 6c, 6d, 6e stator teeth, 7 slits, 8 rotor core, 9 stator core, 10 fixed Child winding, 11 rotor magnetic pole center line, 12
Rotor anti-rotation direction side core, 13 rotor rotation direction side core.

Claims (4)

[Claims] 1. A stator having a coil wound around a cylindrical stator core, a rotor core provided inside the stator, and a plurality of magnet insertion holes formed in the rotor core. A rotor having a permanent magnet inserted into the magnet insertion hole; and a rotor provided on the rotor, the rotor being located on the rotor anti-rotation side with respect to the rotor magnetic pole center line of the outer peripheral side iron core portion of the magnet insertion hole. And a slit formed in the center line direction of the rotor magnetic pole. 2. The permanent magnet type motor according to claim 1, wherein the slit has a gap side opening that opens on a gap side existing between the stator and the rotor. 3. The permanent magnet motor according to claim 1, wherein the slit has a permanent magnet side opening that opens to the permanent magnet side. 4. The permanent magnet type motor according to claim 1, further comprising a nonmagnetic filler filled in the slit.