JP2001069701A - Magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the induction of torque ripples in order to narrow the width of the torque ripple and to control the occurrence of vibration and noise, by forming the cross sectional shape of the outside circumference of a rotor in a sinusoidal waveform by making the radius of the rotor smallest at the positions of the ends of magnetic poles and largest at the positions of their central parts. SOLUTION: A plurality of flat-plane permanent magnets 107 are embedded near the surface of the outside circumference of a rotor 102. Also, air ranges 114 for preventing the short-circuit of magnetic paths are drilled in an iron core 106 between both ends of the magnetic poles of the permanent magnets 107, by cutting out a part of the iron core 106 which exists at the positions by the width corresponding to the thickness of the permanent magnet 117. Then, the shape of the outside circumference of the rotor 102 is set in a sinusoidal waveform, in the range from q-axis between each of the neighboring ends to the same q-axis in the opposite ends of the magnetic poles in the outside circumference of one magnetic pole of each permanent magnet 107, by making the radius of the rotor smallest at the positions of the q-axis and largest at that of d-axis that corresponds to the central position of the magnetic poles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet motor used in a hermetic compressor.

[0002]

2. Description of the Related Art An outline of a conventional magnet motor of a hermetic compressor will be described with reference to FIGS. 6A and 6B illustrate a conventional hermetic compressor magnet motor, in which FIG. 6A is a longitudinal section taken along line AA in FIG. 6B, and FIG.
FIG. 7 shows a longitudinal section along line -B, and FIG. 7 shows a transverse section of a conventional rotor arranged at the center of the magnet motor of FIG.

That is, reference numeral 10 denotes a magnet motor, which comprises two main parts, a stator 1 and a rotor 2.

In the stator 1, a large number of electric wires 5 are wound around a cylindrical core 3 formed by laminating a large number of thin magnetic steel sheets through a plurality of slots 4 provided at predetermined intervals in a circumferential direction thereof. It is constituted by that.

[0005] On the other hand, the rotor 2 has a cylindrical iron core 6 formed by laminating a number of thin magnetic steel plates, and is disposed at a predetermined interval in the circumferential direction of the iron core 6. And a plurality of (four in the figure) permanent magnets 7 buried as close to the outer surface of the rotor 2 as manufacturing permits, and a rotating shaft 8 is provided at the center of the iron core 6. It is fixed through.

An upper end plate 1 is provided at the upper end of the rotor 2.
1, a lower end plate 12 is disposed at the lower end, and the iron core 6 and the permanent magnet 7 disposed between the upper end plate 11 and the lower end plate 12 are integrally fixedly fastened together with rivets 13 to form the rotor 2. ing.

In the arrangement of the permanent magnets 7 having the above-described structure, the magnetic flux generated by the permanent magnets 7 forms a magnetic circuit in the rotor 2 due to the presence of the iron cores 6 formed at both ends of the adjacent permanent magnets 7. In order to prevent a magnetic path short-circuiting structure, a part of the iron core 6 interposed between the magnetic pole ends of the permanent magnet 7 is cut out, and the thickness L of the permanent magnet 7 is reduced.
An air region 14 having substantially the same width as that of the rotor 2 and a shape along the outer periphery of the rotor 2 is provided.

[0008]

However, in the conventional rotor 2 configured as described above, the air region 14 formed between the magnetic pole tips of the adjacent permanent magnets near the outer periphery of the rotor 2 is provided. By this, the bias of the magnetic flux on the d-axis passing through the center of the magnetic pole of the permanent magnet of the rotor 2 and the q-axis passing between the pole tips of the adjacent permanent magnets is reduced, but the black dots in FIG. 4 and FIG. As shown including the plotted "R (circular)" data, the gap magnetic flux density distribution by the permanent magnet 7 becomes rectangular (see FIG. 4) and induces torque pulsation in many high-order components of spatial harmonics. In addition, the maximum torque pulsation width becomes larger than the average generated torque (see FIG. 5), and there is a problem that vibration and noise are generated.

The present invention solves such a problem in the rotor of the conventional magnet motor, suppresses the induction of torque pulsation, reduces the torque pulsation width, and suppresses the generation of vibration and noise. It is an object to provide a motor.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an iron core is formed by laminating a large number of thin magnetic steel sheets, and a predetermined interval is provided in the circumferential direction of the iron core. In a magnet motor having a rotor in which a plurality of permanent magnets are arranged and buried so that their magnetic poles face in the circumferential direction and a fixed shaft is fixed through the center of the iron core, permanent magnets adjacent in the circumferential direction are used. While drilling an air region for preventing magnetic path short circuit in a part of the iron core interposed between the magnetic pole tips, the outer peripheral shape in the cross section of the rotor, the radius of the rotor is minimized at the position of the magnetic pole tip, An object of the present invention is to provide a magnet motor formed by changing a sine wave so as to be maximum at a position of a magnetic pole center.

That is, according to the present invention, the radius of the rotor is made different between the position of the magnetic pole end and the position of the center of the magnetic pole, and the sine wave is changed between the former position being the minimum and the latter being the maximum. The torque pulsation width is reduced by suppressing the induction of torque pulsation, thereby suppressing the generation of vibration and noise.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a magnet motor according to the present embodiment, and FIGS. 2 and 3 are cross-sectional views of a rotor in which a certain difference is given to the shape of the rotor for convenience of explanation. FIG. 3 shows a case where the radius of curvature of the rotor at the center is small, FIG. 3 shows a case where the radius of curvature of the rotor at the center of the magnetic pole is large, FIG. 4 is an explanatory view showing a gap magnetic flux density distribution with respect to the rotor electrical angle, and FIG. is there.

In this embodiment, the stator 101
In the magnet motor 110 mainly including the rotor 102 and the rotor 102, the stator 101 is the same as the above-described conventional motor, and thus the description thereof is omitted, and the rotor 102 will be described.

That is, the rotor 102 forms an iron core 106 by laminating a large number of thin magnetic steel plates, and a rotary shaft 108 is fixed through the center of the iron core 106.
, A plurality (four in this case) of plate-shaped permanent magnets 107 are arranged at predetermined intervals in the circumferential direction, and their magnetic poles face in the circumferential direction, and as close to the outer peripheral surface of the rotor 102 as possible. Are embedded and fixedly fastened together with rivets 113.

The iron core 106 between the two magnetic pole ends of the permanent magnet 107 has a width corresponding to the thickness of the permanent magnet 107, and a part of the iron core 106 interposed therebetween is cut off to short-circuit the magnetic path. An air region 114 for prevention is provided.

The outer peripheral shape of the rotor 102 is such that, at the outer circumference of one magnetic pole of each permanent magnet 107, the rotor 102 extends from the q-axis between adjacent pole tips to a similar q-axis at the opposite pole tip. The shape of the sine wave is set such that the radius of 102 becomes minimum at the position of the q-axis and maximum at the position of the d-axis corresponding to the center of the magnetic pole.

In the present embodiment having the above-described configuration, it is assumed that the shape of the sine wave-changing shape is different, and the radius of the rotor 102 is now the radius of the q axis and the radius of the d axis. the varying radius what difference is half sheets of the cross-sectional shape of the thickness L of the permanent magnet 107 shown in FIG. 2 from the q-axis in this case up to d-axis and R _1, also the permanent magnet 10
7 is a cross-sectional shape of one sheet having a thickness L of FIG. 7, and in this case, the radius changing from the q axis to the d axis is R _2, and the radius of the rotor 102 in each case is as follows. Is set by the following equation.

R ₁ = (AL / 2) + L / 2 sin θ (case of FIG. 2); R ₂ = (AL) + L sin θ (case of FIG. 3); where R ₁ , R ₂ : change of the rotor 102 Radius: A: radius of rotor 102 on d axis (R ₁ = R ₂ ); L: thickness of permanent magnet 107; θ: electrical angle (0 ° ≦ θ ≦ 180 °); changes from q axis to d axis Regardless of whether the radius of the rotation is R ₁ or R ₂ , the outer peripheral shape of the rotor 102
At the outer circumference of one pole, between the pole tip (q axis) and the opposite pole tip (q axis), the radius of the rotor 102 is minimum on the q axis and maximum at the center of the pole (d axis). The air gap formed by the rotor 102 and the stator 101 having a cylindrical inner surface changes in a sinusoidal manner.

As shown by “R ₁ (small curvature)” plotted with black triangles and “R ₂ (large curvature)” plotted with open squares in FIGS. 4 and 5, gap magnetic flux density distribution and The torque pulsation has a smaller width than that shown by "R (circular shape)" described as the related art.

In the case where the changing radius shown in FIG. 2 is R ₁ , as described above, one-half of the thickness of the permanent magnet 107 is used.
A change in sheets, which compared the varying radius in FIG. 3 was changed one sheet to those with R _2, the former because the radius of curvature is larger the R ₁ and the small-curvature than the latter, the curvature size of R ₂ In the comparison between R ₁ and R ₂ , R ₂ is greater than R ₁ .
The width is further reduced and reduced.

This means that the magnitude of the curvature of the outer periphery of the d-axis rotor 102 can be selected according to the magnitude of the difference between the radius of the rotor 102 on the q-axis and the radius of the rotor 102.

Thus, according to the present embodiment, the rotor 1
02, as the curvature of the outer circumference increases, the gap magnetic flux density distribution approaches a sine wave from a rectangular wave (see FIG. 4), and the maximum torque pulsation with respect to the generated torque decreases (see FIG. 5).
Therefore, vibration and noise can be effectively reduced.

Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited to such embodiments.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

[0024]

As described above, according to the present invention, an iron core is formed by laminating a large number of thin magnetic steel sheets, and a plurality of permanent magnets whose magnetic poles are formed at predetermined intervals in the circumferential direction of the iron core. In a magnet motor having a rotor arranged and buried so as to face in the circumferential direction and having a fixed shaft penetrated and fixed at the center of the iron core, the iron core interposed between the magnetic pole ends of the permanent magnets adjacent in the circumferential direction is A part of the air region for preventing a magnetic path short circuit is formed, and the outer peripheral shape in the cross section of the rotor is set so that the radius of the rotor is minimized at the position of the magnetic pole tip and maximized at the position of the magnetic pole center. Since the magnet motor is formed by changing the sine wave, the radius of the rotor is made different between the position of the magnetic pole end and the position of the center of the magnetic pole, and the former position is minimized, and the latter position is maximized. Wave change prevents torque pulsation induction And to reduce the torque pulsation width, by suppressing the generation of vibration and noise, in which it was possible to obtain a suitable magnet motor.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing an example of a rotor incorporated in the magnet motor of FIG.

FIG. 3 is a cross-sectional view showing another example of a rotor incorporated in the magnet motor of FIG.

FIG. 4 is an explanatory diagram illustrating a gap magnetic flux density distribution with respect to a rotor electrical angle.

FIG. 5 is an explanatory diagram showing a motor generated torque with respect to a rotor position.

6A and 6B show a conventional magnet motor, wherein FIG. 6A shows A of FIG.
FIG. 4B is a longitudinal sectional view along the line A, and FIG. 4B is a longitudinal sectional view along the line BB in FIG.

FIG. 7 is a cross-sectional view showing a rotor incorporated in the magnet motor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Rotor 3 Cylindrical core 4 Slot 5 Electric wire 6 Iron core 7 Permanent magnet 8 Rotation axis 10 Magnet motor 11 Upper end plate 12 Lower end plate 13 Rivets 14 Air area 101 Stator 102 Rotor 106 Iron core 107 Permanent magnet 108 Rotation axis 110 Magnet Motor 113 Rivets 114 Air area

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[Procedure amendment]

[Submission date] February 10, 2000 (2000.2.1
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

In the present embodiment having the above-described configuration, it is assumed that the shape of the sine wave-changing shape is different, and the radius of the rotor 102 is now the radius of the q axis and the radius of the d axis. the varying radius what difference is half sheets of the cross-sectional shape of the thickness L of the permanent magnet 107 shown in FIG. 2 from the q-axis in this case up to d-axis and R _1, also the permanent magnet 10
7 is a cross-sectional shape corresponding to one sheet having a thickness L of FIG. 7, and the radius of change from the q-axis to the d-axis in that case is R _2, and the radius of the rotor 102 in each case is Is set by the following equation.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

[0018] (in the case of FIG. _{2) R 1 = (A-} L / 2) + L / 2 sinθ; R 2 = (A-L) + L sinθ ( case of FIG. 3); wherein R _1, R _2: rotor A: radius of the rotor 102 on the d axis (R ₁ = R ₂ ); L: thickness of the permanent magnet 107; θ: electrical angle (0 ° ≦ θ ≦ 180 °); from the q axis Regardless of whether the radius changing up to the d-axis is R ₁ or R ₂ , the outer peripheral shape of the rotor 102
At the outer circumference of one pole, between the pole tip (q axis) and the opposite pole tip (q axis), the radius of the rotor 102 is minimum on the q axis and maximum at the center of the pole (d axis). The air gap formed by the rotor 102 and the stator 101 having a cylindrical inner surface changes in a sinusoidal manner.

Continued on the front page (72) Inventor Makoto Hattori 3-1-1 Asahicho, Nishibiwajima-cho, Nishi-Kasugai-gun, Aichi Prefecture Inside Air Conditioning Works of Mitsubishi Heavy Industries, Ltd. (72) Inventor: Shinichi Isobe, Nagoya City, Nagoya City, Nagoya, Nagoya, Iwazuka, Nagoya, Machinery Works (72) Inventor: Mitsubishi Heavy Industries, Ltd. Address Mitsubishi Heavy Industries, Ltd. Nagoya Laboratory F-term (reference) 5H622 AA03 CA02 CA07 CA13 CB05 CB06 PP10 PP11 PP14 PP16

Claims (1)

[Claims] An iron core is formed by laminating a large number of thin magnetic steel plates, and a plurality of permanent magnets are arranged at predetermined intervals in a circumferential direction of the iron core so that their magnetic poles face in a circumferential direction. In a magnet motor having a rotor embedded and fixed with a fixed shaft passing through the center of the iron core, a part of the iron core interposed between the magnetic pole ends of the permanent magnets adjacent in the circumferential direction is used to prevent a magnetic path short circuit. And the outer peripheral shape in the cross section of the rotor is formed by changing the sine wave so that the radius of the rotor is minimum at the position of the magnetic pole tip and maximum at the position of the magnetic pole center. A magnet motor.