JP2004328956A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor with reduced iron loss, torque ripples and harmonic components within a no-load induced voltage. <P>SOLUTION: This motor is provided with a rotor 10. A slot 14 is formed in the peripheral of the rotor 10. A straight line 12, connecting a deepest low point 15 from a peripheral surface 13 in the slot 14 and the center of the rotor 10 makes an electrical angle ϕ, which is 40 or larger and 44° or smaller to the center line 11 of the pole which is the nearest to the low point 15. The torque ripples and the iron loss can be reduced by the slot 14. When the electrical angle ϕ is larger than 44° and smaller than 53°or less, the harmonic components in the no-load induced voltage can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a motor, and more particularly to a motor mounted on a vehicle.
[0002]
[Prior art]
Conventionally, an electric motor is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-78260 (Patent Document 1).
[0003]
[Patent Document 1]
JP 2002-78260 A
[Problems to be solved by the invention]
There is a demand for a motor mounted on a vehicle to reduce torque ripple. This torque ripple indicates a variation in output torque as a percentage of the average torque, and it is generally known that the larger the torque ripple, the greater the vibration and noise of the electric motor.
[0005]
Further, in the electric motor, it is required to reduce the harmonic content of the no-load induced voltage. The no-load induced voltage is the induced voltage generated in the stator (stator) when the rotor of the motor is rotated, and when this contains many harmonics, the effective value of the voltage The peak value for is higher. For this reason, the no-load induced voltage exceeds the withstand voltage of the system at the maximum rotation speed, which causes insulation breakdown of the inverter parts. Further, when an electric system is configured to withstand a motor having a high harmonic content, the peak value of the voltage due to the harmonics determines the withstand voltage of the system. As a result, the effective value of the voltage that affects the output torque cannot be improved, resulting in an increase in the current value and an increase in the size of the motor. Therefore, in order to reduce the size of the motor, it is necessary to reduce the harmonic content of the no-load induced voltage.
[0006]
Furthermore, an increase in iron loss leads to a decrease in efficiency and a decrease in fuel efficiency of the hybrid vehicle.
[0007]
Then, this invention is made in order to solve the above-mentioned problem, and an object of this invention is to provide an electric motor with small torque ripple and iron loss.
[0008]
It is another object of the present invention to provide a motor having a low harmonic content of no-load induced voltage.
[0009]
[Means for Solving the Problems]
An electric motor according to one aspect of the present invention includes a stator having a plurality of winding phases formed by distributed winding, and a rotor having a plurality of magnetic poles and having an outer periphery facing the stator. . A groove is formed on the outer periphery of the rotor. Of the grooves, a straight line connecting the bottom point, which is the deepest from the outer peripheral surface, to the center of the rotor makes an electrical angle of 40 ° or more and less than 44 ° with respect to the center line of the magnetic pole closest to the bottom point. .
[0010]
In the motor configured as described above, the electric angle of the bottom point is optimized, so that the torque ripple and the iron loss of the motor can be reduced. If the electric angle is less than 40 °, the effect of reducing torque ripple and iron loss is reduced. Further, when the electrical angle is 44 ° or more, the effect of reducing the torque ripple decreases.
[0011]
A motor according to another aspect of the present invention includes a stator having a plurality of winding phases formed by distributed winding, and a rotor having a plurality of magnetic poles and having an outer periphery facing the stator. . A groove is formed on the outer periphery of the rotor. A straight line connecting the center of the rotor and the bottom point having the deepest depth from the outer peripheral surface of the groove forms an electrical angle of 44 ° to 53 ° with respect to the center line of the magnetic pole closest to the bottom point. .
[0012]
In the electric motor configured as described above, since the angle of the bottom point is optimized, the content of harmonics in the no-load induced voltage can be reduced. Note that, regardless of whether the angle is less than 44 ° or more than 53 °, the harmonic content in the no-load induced voltage is less likely to decrease.
[0013]
A motor according to another aspect of the present invention includes a stator having a plurality of winding phases formed by distributed winding, and a rotor having a plurality of magnetic poles and having an outer periphery facing the stator. . First and second grooves are formed on the outer periphery of the rotor. In the first groove, a straight line connecting the first bottom point, which is deepest from the outer peripheral surface, to the center of the rotor is 40 ° with respect to the center line of the magnetic pole closest to the first bottom point. The electrical angle is not less than 44 °. In the second groove, a straight line connecting the second bottom point, which is the deepest from the outer peripheral surface, to the center of the rotor is 44 ° with respect to the center line of the magnetic pole closest to the second bottom point. The electrical angle is not less than 53 °.
[0014]
In the electric motor configured as described above, torque ripple and iron loss can be reduced by the first bottom point. Furthermore, the second bottom point can reduce the content of harmonics in the no-load induced voltage.
[0015]
A motor according to another aspect of the present invention includes a stator having a plurality of winding phases formed by distributed winding, and a rotor having a plurality of magnetic poles and having an outer periphery facing the stator. . A concave portion having a bottom surface whose depth from the outer peripheral surface is substantially constant is formed in the outer periphery of the rotor. A straight line connecting one end of the bottom surface and the center of the rotor makes an electrical angle of 40 ° or more and less than 44 ° with respect to the center line of the magnetic pole closest to the one end. A straight line connecting the other end of the bottom surface and the center of the rotor makes an electrical angle of 44 ° to 53 ° with respect to the center line of the magnetic pole closest to the other end.
[0016]
In the motor configured as described above, iron loss and torque ripple can be reduced by one end.
[0017]
Further, the content of harmonics in the no-load induced voltage can be reduced by the other end.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or corresponding portions are denoted by the same reference characters, and description thereof will not be repeated.
[0019]
(Embodiment 1)
FIG. 1 is a sectional view of an electric motor according to Embodiment 1 of the present invention. FIG. 2 is an enlarged sectional view showing a portion surrounded by II in FIG. Referring to FIGS. 1 and 2, electric motor 1 according to the first embodiment of the present invention includes a plurality of winding phases formed by distributed winding as U-phase 110U, V-phase 110V, and W-phase 110W. And a rotor 10 having a plurality of permanent magnets 30 as magnetic poles and having an outer periphery facing the stator 100. A groove 14 is formed on the outer periphery of the rotor 10. The straight line 12 connecting the bottom point 15 having the deepest depth from the outer peripheral surface 13 and the center 120 of the rotor 10 to the center line 11 of the magnetic pole closest to the bottom point 15 in the groove 14 is equal to or more than 40 °. Make an electrical angle φ of less than °.
[0020]
The stator 100 has an annular core body 103. The core body 103 is made of a magnetic material such as iron or an iron alloy. A plurality of (48) teeth portions 101 are formed on the inner peripheral surface of the core body 103, and a slot portion 102 is formed between each of the tooth portions 101. The tooth part 101 has a “convex” shape, and the slot part 102 has a “concave” shape. The slot 102 is open toward the inner peripheral side of the core body 103.
[0021]
In the teeth portion 101, a U-phase 110U, a V-phase 110V, and a W-phase 110W are formed as winding phases by distributed winding. A U-phase 110U, a V-phase 110V, and a W-phase 110W are arranged in this order from the outer peripheral side. The U-phase 110U, the V-phase 110V, and the W-phase 110W may be formed by any of a method of winding using an inserter and a method of directly winding the teeth 101.
[0022]
An AC voltage is applied to U phase 110U, V phase 110V, and W phase 110W, and an AC magnetic field is generated in a direction penetrating through U phase 110U, V phase 110V, and W phase 110W as coils.
[0023]
The rotor 10 has a core body 20 made of a magnetic material such as iron or an iron alloy. A permanent magnet 30 constituting a plurality of magnetic poles is embedded in the core body 20. At both ends of the permanent magnet 30, hollow portions 40 are provided. The center line 11 of the magnetic pole is located between the two permanent magnets 30. The pole centerline 11 passes through the center 120 of the rotor 10. The rotor 10 is joined to the rotation shaft 130, and the rotation of the rotation shaft 130 causes the rotor 10 to also rotate.
[0024]
As shown in FIG. 2, a plurality of grooves 14 (dents) are formed on the outer peripheral surface 13 of the rotor 10. Each of the grooves 14 is rectangular, but may be formed in a gentle arc. The bottom point 15 of the groove 14 is a portion of the groove 14 where the depth from the outer peripheral surface 13 is deepest, and the position of the bottom point 15 determines the characteristics of the electric motor. In this embodiment, the straight line 12 connecting the bottom point 15 and the center 120 of the rotor 10 forms an electrical angle φ of 40 ° or more and less than 44 ° with respect to the center line 11 of the magnetic pole closest to the bottom point 15. . Preferably, electric angle φ is not less than 41 ° and not more than 43 °.
[0025]
In the electric motor 1 configured as described above, the straight line 12 connecting the bottom point 15 of the groove 14 and the center 120 of the rotor 10 is at least 40 ° and 44 ° with respect to the center line 11 of the magnetic pole closest to the bottom point 15. Since the electric angle φ is smaller than the above, the torque ripple and the iron loss of the electric motor 1 can be reduced. Therefore, it is possible to provide the electric motor 1 with small vibration and low power consumption.
[0026]
(Embodiment 2)
FIG. 3 is a cross-sectional view of a rotor used in the electric motor according to Embodiment 2 of the present invention. Referring to FIG. 3, in rotor 10 according to Embodiment 2 of the present invention, groove 14 is formed on the outer periphery of rotor 10. The straight line 12 connecting the center of the rotor 10 and the bottom point 15 having the deepest depth from the outer peripheral surface 13 of the groove 14 is at least 44 ° to the center line 11 of the magnetic pole closest to the bottom point 15. It forms an electrical angle φ of less than °. Other structures of the stator 100 are the same as those of the first embodiment.
[0027]
In the thus configured electric motor according to the second embodiment, the straight line 12 connecting the bottom point 15 and the center of the rotor is at least 44 ° with respect to the center line 11 of the magnetic pole closest to the bottom point 15. Since the angle is less than or equal to °, the harmonic component of the no-load induced voltage can be reduced. Therefore, a small-sized and high-output motor can be provided.
[0028]
(Embodiment 3)
FIG. 4 is a cross-sectional view of a rotor used in the electric motor according to Embodiment 3 of the present invention. Referring to FIG. 4, in rotor 10 according to Embodiment 3 of the present invention, first groove 14a and second groove 14b are formed on the outer periphery. In the first groove 14a, a straight line 12a connecting the first bottom point 15a whose depth from the outer peripheral surface 13 is the deepest and the center of the rotor 10 is the center of the magnetic pole closest to the first bottom point 15a. An electric angle φ1 of 40 ° or more and less than 44 ° with respect to the line 11 is formed. Among the second grooves 14b, a straight line 12b connecting the second bottom point 15b whose depth from the outer peripheral surface 13 is the deepest and the center of the rotor 10 is the center of the magnetic pole closest to the second bottom point 15b. An electric angle φ2 of 44 ° or more and 53 ° or less with respect to the line 11 is formed.
[0029]
In this embodiment, a gentle convex portion is formed between the first bottom point 15a and the second bottom point 15b. The height of this convex portion is shown in FIG. It may be higher or lower.
[0030]
In the electric motor according to Embodiment 3 of the present invention, the straight line 12a connecting the first bottom point 15a and the center line of the rotor 10 has the magnetic pole closest to the first bottom point 15a. Has an electric angle φ1 of 40 ° or more and less than 44 ° with respect to the center line 11 of the motor, the first groove 14a can reduce iron loss and torque ripple of the electric motor.
[0031]
Further, a straight line 12b connecting the second bottom point 15b and the center point of the rotor 10 forms an electrical angle φ2 of 44 ° to 53 ° with respect to the center line 11 of the magnetic pole closest to the second bottom point 15b. Therefore, harmonics of the no-load induced voltage of the motor can be reduced by the second groove 14b.
[0032]
(Embodiment 4)
FIG. 5 is a cross-sectional view of a rotor used in the electric motor according to Embodiment 4 of the present invention. Referring to FIG. 5, in rotor 10 used in the electric motor according to Embodiment 4 of the present invention, the outer periphery of rotor 10 has a substantially constant depth from outer peripheral surface 13 and has a substantially uniform rotation. A recess 24 having a bottom surface 27 extending from one end 25 to the other end 26 along the direction is formed. A straight line 12a connecting one end 25 of the bottom surface 27 and the center of the rotor 10 forms an electrical angle φ1 of 40 ° or more and less than 44 ° with respect to the center line 11 of the magnetic pole closest to the one end 25. A straight line 12b connecting the other end 26 of the bottom surface 27 and the center of the rotor 10 forms an electrical angle φ2 of 44 ° to 53 ° with respect to the center line 11 of the magnetic pole closest to the other end 26.
[0033]
The one end 25 and the other end 26 are ends along the rotation direction of the rotor 10. In addition, the one end 25 and the other end 26 indicate points of intersection of a bottom surface 27 forming a concave portion and an inclined surface connecting the bottom surface 27 and the outer peripheral surface 13.
[0034]
In the electric motor according to the fourth embodiment of the present invention, the straight line 12a connecting one end 25 and the center of the rotor is aligned with the center line 11 of the magnetic pole closest to the one end 25. Since the electrical angle φ1 is equal to or greater than 40 ° and less than 44 °, the one end 25 can reduce torque ripple and iron loss of the electric motor. Further, the straight line 12b connecting the other end 26 and the center of the rotor 10 forms an electrical angle φ2 of 44 ° or more and 53 ° or less with respect to the center line 11 of the magnetic pole closest to the other end 26. With 26, the harmonic component of the no-load induced voltage of the motor can be reduced.
[0035]
【Example】
(Example 1)
In Example 1, in the electric motor according to Embodiment 1, samples in which the electric angle φ was set variously were manufactured. For these samples, torque ripple and iron loss per unit mass of the motor were measured. FIG. 6 shows the result.
[0036]
From FIG. 6, it can be seen that in order to reduce the torque ripple and the iron loss, it is preferable that the electrical angle φ of the bottom point is 40 ° or more and less than 44 °.
[0037]
(Example 2)
In Example 2, the motor according to Embodiment 2 was used to manufacture samples in which the electric angle φ was variously set, and for these samples, the ratio Vp / of the maximum value Vp of the no-load induced voltage to the effective voltage Ve was obtained. Ve was determined. FIG. 7 shows the result.
[0038]
The lower the no-load induced voltage ratio Vp / Ve in FIG. 7, the smaller the harmonic component in the no-load induced voltage.
[0039]
FIG. 7 shows that when the electrical angle φ is 44 ° or more and 53 ° or less, the no-load induced voltage ratio Vp / Ve decreases.
[0040]
(Example 3)
In Example 3, in the electric motor according to Embodiment 3, samples in which the electric angle φ1 was set variously were manufactured. In each sample, the electrical angle φ2 was 52 °. For these samples, torque ripple and iron loss per unit mass of the motor were measured. As a result, the same results as in FIG. 6 were obtained for the relationship between the electrical angle φ1 and the torque ripple and iron loss.
[0041]
In the electric motor according to the third embodiment, samples in which the electric angle φ2 was set variously were manufactured. In each sample, the electrical angle φ1 was 40 °. For these samples, the ratio Vp / Ve between the maximum value Vp of the no-load induced voltage and the effective voltage Ve was measured. As a result, with respect to the relationship between the electrical angle φ2 and the no-load induced voltage ratio Vp / Ve, the same result as in FIG. 7 was obtained.
[0042]
Therefore, if the electric angle φ1 is set to 40 ° or more and less than 44 ° and the electric angle φ2 is set to 44 ° or more and 53 ° or less, an electric motor having small torque ripple and iron loss and small harmonic components in the no-load induced voltage can be obtained. It turned out to be obtained.
[0043]
(Example 4)
In Example 4, in the electric motor according to Embodiment 4, samples in which the electric angle φ1 was set variously were manufactured. In each sample, the electrical angle φ2 was 52 °. For these samples, torque ripple and iron loss per unit mass of the motor were measured. As a result, the same results as in FIG. 6 were obtained for the relationship between the electrical angle φ1 and the torque ripple and iron loss.
[0044]
Further, in the electric motor according to the fourth embodiment, samples in which the electric angle φ2 was set variously were manufactured. In each sample, the electrical angle φ1 was 40 °. For these samples, the ratio Vp / Ve between the maximum value Vp of the no-load induced voltage and the effective voltage Ve was measured. As a result, with respect to the relationship between the electrical angle φ2 and the no-load induced voltage ratio Vp / Ve, the same result as in FIG. 7 was obtained.
[0045]
Therefore, if the electric angle φ1 is set to 40 ° or more and less than 44 ° and the electric angle φ2 is set to 44 ° or more and 53 ° or less, a motor having small torque ripple and iron loss and small harmonic components in the no-load induced voltage can be obtained. It turned out to be obtained.
[0046]
The embodiments and examples disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[0047]
【The invention's effect】
According to the present invention, it is possible to provide an electric motor with small torque ripple and small iron loss.
[0048]
Further, according to the present invention, it is possible to provide a motor having a small harmonic component in the no-load induced voltage.
[Brief description of the drawings]
FIG. 1 is a sectional view of an electric motor according to Embodiment 1 of the present invention.
FIG. 2 is an enlarged sectional view showing a portion surrounded by II in FIG.
FIG. 3 is a sectional view of a rotor used in the electric motor according to Embodiment 2 of the present invention.
FIG. 4 is a sectional view of a rotor used in a motor according to a third embodiment of the present invention.
FIG. 5 is a sectional view of a rotor used in a motor according to a fourth embodiment of the present invention.
FIG. 6 is a graph showing the relationship between the electric angle φ at the bottom point, torque ripple, and iron loss.
FIG. 7 is a graph showing the relationship between the bottom electrical angle φ and the no-load induced voltage ratio Vp / Ve.
[Explanation of symbols]
Reference Signs List 1 motor, 10 rotor, 11 center line, 12, 12a, 12b straight line, 14 grooves, 14a first groove, 14b second groove, 15 bottom point, 15a first bottom point, 15b second bottom point , 24 recess, 25 one end, 26 the other end, 27 bottom surface, 100 stator, 110U U phase, 110V V phase, 110W W phase, 120 center.

Claims (4)

A stator having a plurality of winding phases formed by distributed winding,
A rotor having a plurality of magnetic poles and having an outer periphery facing the stator,
A groove is formed on the outer periphery of the rotor,
Of the grooves, a straight line connecting the bottom point whose depth from the outer peripheral surface is the deepest and the center of the rotor has an electric angle of 40 ° or more and less than 44 ° with respect to the center line of the magnetic pole closest to the bottom point. Eggplant, electric motor. A stator having a plurality of winding phases formed by distributed winding,
A rotor having a plurality of magnetic poles and having an outer periphery facing the stator,
A groove is formed on the outer periphery of the rotor,
Of the grooves, a straight line connecting the bottom point with the deepest depth from the outer peripheral surface and the center of the rotor has an electric angle of 44 ° or more and 53 ° or less with respect to the center line of the magnetic pole closest to the bottom point. Eggplant, electric motor. A stator having a plurality of winding phases formed by distributed winding,
A rotor having a plurality of magnetic poles and having an outer periphery facing the stator,
First and second grooves are formed on the outer periphery of the rotor,
In the first groove, a straight line connecting the first bottom point, which is the deepest from the outer peripheral surface, to the center of the rotor is 40 ° away from the center line of the magnetic pole closest to the first bottom point. Make an electrical angle of at least 44 ° and less than 44 °,
In the second groove, a straight line connecting the second bottom point, which is the deepest from the outer peripheral surface, to the center of the rotor is located at 44 degrees with respect to the center line of the magnetic pole closest to the second bottom point. An electric motor that forms an electrical angle of not less than 53 ° and not more than 53 °. A stator having a plurality of winding phases formed by distributed winding,
A rotor having a plurality of magnetic poles and having an outer periphery facing the stator,
On the outer periphery of the rotor, a recess having a bottom surface whose depth from the outer peripheral surface is substantially constant and extends from one end to the other end along the rotation direction of the rotor is formed, and one end of the bottom surface is formed. The straight line connecting the center of the rotor forms an electrical angle of 40 ° or more and less than 44 ° with respect to the center line of the magnetic pole closest to one end thereof,
A motor, wherein a straight line connecting the other end of the bottom surface and the center of the rotor forms an electrical angle of 44 ° or more and 53 ° or less with respect to a center line of a magnetic pole closest to the other end.

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