JP2000014058A - Permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adaptive economical motor by combining magnet torque and reluctance torque. SOLUTION: In a permanent magnet motor which has a rotor 10 inside a stator 1 generating a rotating magnetic field, a magnet 11 semicylindrical in cross section, which secures a specified width (width of a projection a) of magnetic path form one q axis to the other q axis as regards the magnetic path from the stator 1 and besides lies along the periphery of the said rotor 10, in the vicinity of the q axis on the periphery side of this secured magnetic path, is buried in the stator 10, and a calking section 12 is made near the q axis. The half of the width of the above magnetic path is put in the range of 2πR/16-2πR/32 (R: radius of rotor) to 2# R/16+2πR/32, and effective synthesized torque (torque where magnetic torque and reluctance torque are combined) is generated by considering the cost.

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 for a motor used in an air conditioner or an automobile, and more particularly to a permanent magnet motor combining a magnet torque and a reluctance torque.

[0002]

2. Description of the Related Art As shown in FIG. 4, for example, a permanent magnet motor has a rotor 2 in a stator 1 having 24 slots, and the rotor 2 has the number of poles (4
Poles) of permanent magnets 3 are arranged in the circumferential direction along the outer diameter. Reference numeral 4 denotes a center hole for the shaft. In addition, since the magnet torque is increased by increasing the amount of magnets in order to use the rotor 2 without waste, a permanent magnet motor that generates a large torque can be obtained.

On the other hand, for example, as shown in FIG. 5, a reluctance motor not using a magnet has already been proposed. This reluctance motor has a rotor 5 in a 24-slot stator 1 similar to the permanent magnet motor. are doing. The outer periphery of the rotor 5 has an uneven shape, and the uneven portions are formed at equal intervals by the number of poles (four poles) of the reluctance motor. This makes it easier for one (q-axis) magnetism from the stator 1 to pass through the rotor 5 through the protruding portion, and the other (d-axis) magnetism passes through the rotor 5 by the recessed portion (flux barrier). It becomes difficult to pass.

[0004] The rotor 5
The inside is non-uniform in reluctance, and salient poles are formed in the protruding portions thereof.
Rotates. Therefore, the permanent magnet motor can obtain a larger torque than the reluctance motor because the magnet is used, and the reluctance motor is less expensive than the permanent magnet motor because the magnet is not used.

[0005]

However, in the above-described permanent magnet motor, the permanent magnet 3 obstructs the magnetic path from the stator 1, that is, hardly generates reluctance torque, whereas in the reluctance motor, the rotor 5 The concave portion (flux barrier) provided in (1) is a useless space. As described above, in the permanent magnet motor and the reluctance motor, effective use is limited in consideration of torque and cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an adaptive motor by combining magnet torque and reluctance torque, and to expand use of the motor in consideration of economy. It is an object of the present invention to provide a permanent magnet motor as described above.

[0007]

To achieve the above object, the present invention relates to a permanent magnet motor having a rotor inside a stator for generating a rotating magnetic field, wherein the rotor has a magnetic path from the stator. A predetermined magnetic path width is secured from one q-axis to the other q-axis, and a magnet is embedded in a shape along the outer periphery of the rotor near the d-axis on the outer peripheral side of the secured magnetic path. It is characterized by becoming.

In this case, the permanent magnet motor having the rotor has four poles, and the magnetic path width secured in the rotor is 2 poles.
From πR / 16-2πR / 32 (R; radius of rotor), 2
It is preferable to set the range of πR / 16 + 2πR / 32.

The rotor is a core formed by punching out an electromagnetic steel sheet by an automatic press and punching out a hole having a sectional shape of the magnet and automatically laminating in a mold, and it is preferable to form a caulked portion during the automatic lamination.

[0010] The width between the outer periphery of the magnet and the outer periphery of the rotor may be set in a range of 1 to 3 times the thickness of the core sheet constituting the core.

It is preferable that the rotor is incorporated into a DC brushless motor.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS. In the figure,
4 and 5 are denoted by the same reference numerals, and redundant description will be omitted.

The permanent magnet motor of the present invention can generate not only magnet torque but also reluctance torque by embedding the magnet in a portion corresponding to the flux barrier (recess shown in FIG. 5) of the reluctance motor. The present invention focuses on the fact that an adaptive motor can be obtained, including economy, by making use of the advantages of a permanent magnet motor and a reluctance motor.

For this reason, as shown in FIG. 1, the rotor 10 of this permanent magnet motor has one (q-axis;
In order to secure a magnetic path of a reluctance motor (corresponding to the d-axis), magnets 11 having a semi-cylindrical cross section are embedded at equal intervals by the number of poles. In this case, the adjacent magnets 11 are arranged so as to have different polarities.

Therefore, the amount of the magnets 11 is smaller than that of the conventional permanent magnet motor, that is, the distance between the adjacent magnets 11 of different polarity is increased, and the salient pole portion between the adjacent magnets 11 of different polarity is formed. The portion a is formed, and the magnetism from the stator 1 easily passes from one q-axis to the other q-axis. On the other hand, the magnet 11 functions as a flux barrier, that is, it is difficult for the magnetism from the stator 1 to pass from one d-axis to the other d-axis (corresponding to the q-axis to the q-axis in the reluctance motor).

Here, a magnetic path width x passing from one q-axis to the other q-axis will be described with reference to FIGS. 2, the same and corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

When this permanent magnet motor is a four-pole motor, half of the magnetic path width x is from a minimum value of zero to a maximum value D (= R / (square root of 2); (Radius) (see FIG. 2). The relationship between the torque or the cost and the magnetic path width can be represented by a graph shown in FIG.

As is clear from FIG. 2, the magnet torque sharply decreases because the amount of the magnet 11 decreases as x increases. The reluctance torque sharply increases halfway, and decreases sharply after reaching the maximum value. That is, the magnet 11 interposed in the magnetic path (q-axis) from the stator 1 is reduced to a certain extent to secure a magnetic path, and after reaching the maximum value, the magnet 11 is connected to the magnetic path of the d-axis. This is because the intervening magnet 11 becomes smaller and eventually becomes zero.

The combined torque obtained by combining the magnet torque and the reluctance torque is shown by a two-dot chain line in FIG. 2, that is, the combined torque increases after decreasing, reaches a local maximum value near the maximum value of the reluctance torque, and then sharply decreases thereafter. . Further, the cost (material cost) decreases in proportion to the decrease in the amount of the magnet 11 used, and converges to the cost of only the last electromagnetic steel sheet.

Looking at the ratio of combined torque / cost, as shown by the solid line in FIG. 2, the maximum value is obtained near the maximum value of the reluctance torque, and then sharply decreases. Therefore, x at which the ratio of the combined torque / cost takes the maximum value is 2πR / 16−2πR / 3 for a 4-pole motor.
It can be estimated to be in the range of 2πR / 16 + 2πR / 32 from 2.

In consideration of the torque and the cost,
2πR / 16 + 2πR from πR / 16-2πR / 32
If x is determined within the range of / 32 and the dimensions of the magnet 11 are determined based on this, a motor that is the most economical and generates the most effective torque can be obtained.

Further, the magnet 1 is formed by the method described above.
After determining the dimensions of 1, the rotor 10 is formed with the holes of the magnet 11 and the caulked portion 12 by an automatic lamination method described later. The width of the outer circumferential bar of the hole of the magnet 11, that is, the width between the outer circumference of the magnet 11 and the outer circumference of the rotor 11 is preferably in the range of 1 to 3 times the thickness t of the core sheet to be automatically laminated (see FIG. 2). ).

Incidentally, in manufacturing the rotor 10,
A core lamination method (automatic lamination method) is used in which an electromagnetic steel sheet is punched out by an automatic press using a core press die and caulked in the die to be integrally formed. In this press working step, at the time of punching the core 11 of the rotor 10, at least a hole corresponding to the permanent magnet 11 is punched, and the caulked portion 12 is formed every time a core sheet is laminated.

Therefore, the press working by the conventional automatic lamination method can be used as it is. In this way, the magnet 11 is buried in the hole of the core of the rotor 10 which is automatically pressed and laminated and the core is caulked, and the magnet 11 is magnetized and magnetized.

It should be noted that FIG.
Although the three-phase (U-phase, V-phase and W-phase) armature windings are applied to the four-slot stator core 1, the number of slots and the armature windings may be different. Further, in the stator core 1, for example, the outer-diameter winding is a U-phase, the inner-diameter winding is a W-phase, and an intermediate winding is a V-phase.

If the rotor 10 formed as described above is incorporated into a DC brushless motor, for example, used as a compressor motor of an air conditioner, the performance (operation) of the air conditioner can be increased without increasing the cost. (Efficiency increase, vibration and noise reduction) can be achieved.

[0027]

As described above, according to the first aspect of the present invention, in a permanent magnet motor having a rotor inside a stator that generates a rotating magnetic field, the permanent magnet is fixed to the rotor. Q with respect to the magnetic path from the
Since a predetermined magnetic path width is secured from the axis to the other q-axis, and a magnet is embedded in a shape along the outer periphery of the rotor near the d-axis on the outer peripheral side of the secured magnetic path, An adaptive motor can be obtained by combining torque and reluctance torque, and an adaptive motor can be obtained in consideration of torque and cost. is there.

According to the second aspect of the present invention, the permanent magnet motor having the rotor according to the first aspect has four poles, and the magnetic path width secured in the rotor is 2πR / 16-2πR /
32 (R; radius of the rotor) from 2πR / 16 + 2πR /
Since the range is 32, in addition to the effect of the first aspect, the magnet torque and the reluctance torque can be used to the maximum, and the cost can be reduced.

According to a third aspect of the present invention, in the rotor according to the first or second aspect, the magnetic steel sheet is punched out by an automatic press, and a hole having a sectional shape of the magnet is punched out and a core is automatically laminated in a mold. Since the caulked portion is formed at the time of the automatic lamination, the conventional automatic lamination method can be used as it is in addition to the effect of the first or second aspect, so that the cost does not increase. Also,
By effectively generating reluctance torque, the amount of magnets is also reduced, that is, the magnet occupation ratio in the rotor is reduced, and as a result, the caulked portion can be effectively formed, and the strength of the rotor can be increased. There is an effect that can be.

According to a fourth aspect of the present invention, the width of the outer periphery of the magnet and the outer periphery of the rotor is set to be in a range of 1 to 3 times the thickness of the core sheet constituting the core. Therefore, in addition to the effect of the third aspect, there is an effect that leakage and short circuit of the magnetic flux of the magnet can be prevented, that is, the magnet torque can be effectively generated.

According to the invention described in claim 5, according to claim 1,
Since the DC brushless motor is constructed by incorporating the rotor in 2, 3, or 4, the cost is increased if the rotor is used as a compressor motor of an air conditioner, for example, in addition to the effects of claims 1, 2, 3, or 4. There is an effect that the performance of the air conditioner can be improved without the need.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a permanent magnet motor showing one embodiment of the present invention.

FIG. 2 is a schematic plan view of a rotor for explaining the permanent magnet motor shown in FIG.

FIG. 3 is a schematic graph of torque / cost for explaining the permanent magnet electric motor shown in FIG. 1;

FIG. 4 is a schematic plan view of a conventional permanent magnet motor.

FIG. 5 is a schematic sectional view of a conventional reluctance motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 4 Center hole (for shaft) 10 Rotor 11 Magnet 12 Caulked part a Convex part R Radius of rotor t Thickness of core sheet x Half of magnetic path

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanori Murakami 1116 Suenaga, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu General Co., Ltd. (72) Takashi Suzuki 1116, Suenaga, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu General Limited ( 72) Inventor Hiroyuki Okudera 1116 Suenaga, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu General Limited (72) Inventor Koji Kasai 1116, Suenaga, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu General Limited (72) Inventor Yuji Kawai Kanagawa 1116 Suenaga, Takatsu-ku, Kawasaki-shi Inside Fujitsu General Co., Ltd. QB05

Claims (5)

[Claims] 1. A permanent magnet motor having a rotor inside a stator that generates a rotating magnetic field, wherein the rotor has a predetermined magnetic path from one q axis to the other q axis with respect to the magnetic path from the stator. A permanent magnet electric motor having a width secured and a magnet embedded in a shape along the outer periphery of the rotor near the d-axis on the outer periphery side of the secured magnetic path. 2. A permanent magnet motor having the rotor is
And the magnetic path width secured in the rotor is 2πR / 1.
From 6-2πR / 32 (R; radius of rotor) to 2πR / 1
2. The permanent magnet motor according to claim 1, wherein the range is 6 + 2πR / 32. 3. The rotor is a core formed by punching out an electromagnetic steel sheet by an automatic press, punching out a hole having a sectional shape of the magnet, and automatically laminating in a mold, and forming a caulked portion during the automatic lamination. The permanent magnet electric motor according to claim 1 or 2, wherein: 4. The permanent magnet electric motor according to claim 3, wherein a width between an outer periphery of the magnet and an outer periphery of the rotor is set to be in a range of 1 to 3 times a thickness of a core sheet constituting the core. 5. The permanent magnet motor according to claim 1, wherein said rotor is incorporated into a DC brushless motor.