JP2008178294A - Rotor of permanent-magnet rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it is hard to obtain an excellent distribution in flux in a conventional technique equally allocating permanent magnets in all periphery of a rotor iron core, a distortion rate becomes greater in a cogging torque and the waveform of an induced electromagnetic force, a characteristic is degraded in the rotating electric machine, and the quantity of magnets consumed becomes large because of its allocation in all periphery, resulting in difficulty in saving cost. <P>SOLUTION: A permanent-magnet rotating electric machine has a stator with a plurality of windings; and a rotor having a magnet inside a slot formed in a rotor iron core along its periphery fixed to a rotating shaft rotating inside the stator, and constituted of at least three magnets per a single magnetic pole. A total of electric angles in a group of magnets constituting a single magnetic pole is set in the range of 150°to 165°. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotor of a rotating electrical machine having a permanent magnet, and particularly to an embedded magnet type rotor in which a magnet is embedded in an iron core of a rotor.

  There exists Unexamined-Japanese-Patent No. 2002-44887 as a prior art, and there exists an example which embedded the Nd-Fe-B sintered magnet in the rotor core, and comprised the rotor. The magnet has a flat plate shape that is a single letter in plain view, and is arranged so as to be substantially inscribed on the outer periphery of the rotor and to have a substantially polygonal shape. Further, the magnets are arranged over the entire circumference in the rotor circumferential direction, and the magnetic poles are composed of a plurality of equally divided magnets.

JP 2002-44887 A

  In the above prior art, the magnets are evenly arranged over the entire circumference so as to be inscribed in the outer circumference of the rotor core, so that the magnetic flux distribution is greatly dispersed and a good magnetic flux distribution cannot be obtained. Since the distortion rate of the induced electromotive force waveform is large and the fundamental effective value of the induced electromotive force is lowered, the rotating electrical machine efficiency is lowered. In addition, the cogging torque is increased, the starting current during motor operation is increased, and smooth starting is difficult. Furthermore, since magnets are arranged over the entire circumference of the rotor, there is a problem that the amount of magnets used increases and costs increase.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a permanent magnet type rotating electrical machine that eliminates the above-described problems and has high efficiency, high performance, and low cost.

  In order to achieve the above object, the present invention comprises a rotor having permanent magnets arranged on the inner periphery of a stator having a plurality of armature windings, and is composed of at least three magnets per pole. The total angle of the electrical angle of the magnet group forming one magnetic pole is set to be in the range of 150 to 165 degrees. Thereby, since the magnetic flux is concentrated at the magnetic pole center, a good magnetic flux distribution can be obtained, and the fundamental wave effective value of the induced electromotive force can be increased, so that the rotating electrical machine efficiency is improved. Further, since the magnet group is centrally arranged at the magnetic pole center position, the amount of magnets used is reduced, and an inexpensive permanent magnet type rotating electrical machine can be provided.

  In addition, by arranging the magnets arranged at the magnetic pole end side so that the orientation of the magnet is directed toward the magnetic pole center position, the distortion rate of the induced electromotive force waveform and the cogging torque are reduced, and the current value required at the start of rotation is reduced. At the same time, it is possible to obtain a smooth rotation start. Furthermore, if the inclination angle is in the range of 2 to 6 degrees, the induced electromotive force can be effectively increased, so that high performance of the rotating electrical machine can be realized.

  Furthermore, if the slot shape in which the magnet is accommodated is a shape in which a slit is formed between the magnets, the leakage magnetic flux generated between the magnets is reduced, and the use efficiency of the magnets can be increased. Here, if the magnet fixing material is enclosed in the slit portion, the reliability of the rotor can be improved. In addition, the magnet cost can be reduced by making the above magnet shape into a flat plate shape.

  According to the present invention, it is possible to obtain a high-performance, high-efficiency, and inexpensive permanent magnet type rotating electrical machine.

  Embodiments of a rotating electrical machine according to the present invention will be described below using a two-pole example with reference to the drawings.

  FIG. 1 shows a rotor structure of a permanent magnet type rotating electrical machine that is an embodiment of the rotating electrical machine according to the present invention. The rotor 1 includes a rotor core 2, a slot 3 in which a magnet is accommodated, an N pole side permanent magnet 10, an S pole side permanent magnet 11, a rotating shaft 20, and a plurality of braking windings 4 on the outer peripheral side of the magnets 10, 11. It has. The rotor core 2 is a cylindrical laminated core formed by laminating a plurality of thin iron plates punched into a predetermined shape.

The N-pole side permanent magnet 10 and the S-pole side permanent magnet 11 are magnets that generate a magnetic flux Φ _f and are divided into three parts per magnetic pole. These magnets are arranged in slots 3 installed near the outer peripheral surface portion of the rotor core 2 so as to form two magnetic poles, and each slot 3 is arranged so as to be concentrated in the direction of the magnetic pole center position. Here, if the total angle of the electrical angle of the magnet group constituting one magnetic pole is the circumferential angle θ ₁ of the magnet, various characteristics of the rotating electrical machine can be obtained by setting the circumferential angle θ ₁ of the magnet to an appropriate value. It was found that can be improved significantly. The details will be described below.

FIG. 2 shows the relationship of the circumferential angle θ ₁ of the magnet to the characteristics of the no-load induced electromotive force, the distortion factor of the no-load induced electromotive force waveform, and the cogging torque when the generator is operated. As shown in FIG. 7, in the prior art, magnet groups constituting one magnetic pole are evenly arranged, and the circumferential angle θ ₁ of the magnet per one magnetic pole is a value close to approximately 180 degrees. Therefore, in FIG. 2 the circumferential angle theta ₁ of the magnet according to the prior art and 175 degrees, the circumferential angle theta ₁ of the magnet as well as discussed in the range of 135 degrees to 175 degrees, changing the circumferential angle theta ₁ of the magnet In each case, the results are shown based on the case where the circumferential angle θ ₁ of the magnet is 175 degrees.

In FIG. 2, the no-load induced electromotive force closely related to the efficiency of the permanent magnet type rotating electric machine is larger than that of the prior art, and the distortion factor of the no-load induced electromotive force waveform important as a generator function and the vibration of the rotating electric machine The circumferential angle θ ₁ of the magnet in which the cogging torque that affects the noise is smaller than that in the prior art is in the range of 150 degrees to less than 175 degrees. However, it can be seen that the distortion rate and cogging torque of the no-load induced electromotive force waveform increase rapidly when the circumferential angle θ ₁ of the magnet exceeds 165 degrees. Therefore, when it is desired to reduce mechanical vibration and noise, it can be said that the upper limit in the circumferential angle θ ₁ of the magnet is 165 degrees. Therefore, in the present invention, the range of 150 to 165 degrees is adopted as the optimum range of the circumferential angle θ ₁ of the magnet.

  In FIG. 3, the structure of the rotor 1 of the permanent magnet type rotary electric machine which is other embodiment of the rotary electric machine which concerns on this invention is shown. The rotor 1 includes a rotor core 2, a slot 3 in which a magnet is accommodated, an N pole side permanent magnet 10 (10a, 10b, 10c), an S pole side permanent magnet 11 (11a, 11b, 11c), a rotating shaft 20, and A plurality of braking windings 4 are provided on the outer peripheral side of the magnets 10 and 11. The rotor core 2 is a cylindrical laminated core formed by laminating a plurality of thin iron plates punched into a predetermined shape.

The N-pole side permanent magnet 10 and the S-pole side permanent magnet 11 are magnets that generate a magnetic flux Φ _f and are divided into three parts per magnetic pole. Among these magnet groups, the magnets 10a, 10c, 11a, and 11c located at the magnetic pole end portions are disposed so as to be inclined toward the magnetic pole center position direction. Here, as shown in FIG. 3, the angle Ps toward the magnetic pole center position, that is, the point P _s on the outer peripheral surface of the rotor core 2 on a straight line passing through the two points of the rotation axis center and the magnet center is used as a contact if the tangent L ₁ (= L ₂₎ and the angle formed by the magnet the inclined angle theta ₂ of the magnet, found to be remarkably improved rotary electric machine characteristics by setting the inclination angle theta ₂ of the magnet to an appropriate value It was. The details will be described below.

FIG. 4 shows the relationship of the inclination angle θ ₂ of the magnet with respect to the characteristics of the no-load induced electromotive force, the distortion rate of the no-load induced electromotive force waveform, and the cogging torque when the generator is operated. Here, since the conventional technology has a magnet tilt angle θ ₂ of 0.0 degrees, each result when the magnet tilt angle θ ₂ is changed is the case where the magnet tilt angle θ ₂ is 0.0 degrees. It is written as a standard. In addition, the sign of the angle at which the magnet is tilted is positive for the direction tilted toward the magnetic pole center position.

As shown in FIG. 4, when the inclination angle θ ₂ of the magnet was examined in the range of −2.5 ° to 10.0 °, the no-load induced electromotive force was an angle of 0.0 ° <θ ₂ <10.0 °. Increased in range. Further, it was found that the distortion rate and the cogging torque of the no-load induced electromotive force waveform are small in the entire examination range from −2.5 degrees to 10.0 degrees excluding 0.0 degrees. As a result, a magnet that simultaneously satisfies the condition that the no-load induced electromotive force is large and the distortion factor of the no-load induced electromotive force waveform and the cogging torque are small with respect to the reference characteristic of the magnet inclination angle θ ₂ of 0.0 degrees. It can be seen that the inclination angle θ ₂ is in the range of 0.0 degrees <θ ₂ <10.0 degrees. That is, if the magnet arranged on the magnetic pole end side is tilted in a positive direction, it is possible to improve various characteristics of the rotating electrical machine as compared with the case where the magnet is not tilted. Further, FIG. 4 shows that the no-load induced electromotive force closely related to the efficiency of the permanent magnet type rotating electrical machine is almost the maximum when the inclination angle θ _{2 of the} magnet is set in the range of 2 degrees to 6 degrees. I understand that. Accordingly, in the present invention, in view of the above points, the range of 2.0 degrees to 6.0 degrees is adopted as the optimum range of the magnet inclination angle θ ₂ .

As described above, if any one of the magnet circumferential angle θ ₁ and the magnet inclination angle θ ₂ satisfies the angle range condition of this embodiment, various characteristics of the rotating electrical machine can be improved. Needless to say, if both the magnet circumferential angle θ ₁ and the magnet inclination angle θ ₂ are set to be within the above-mentioned angle range, various characteristics of the rotating electrical machine can be further improved by synergistic action. Further, as shown in FIG. 5, the effect of the present invention is not impaired even when the braking winding 4 described in FIGS. 1 and 3 is not provided. In this case, since the manufacturing cost for the braking winding can be reduced, there is an advantage that a rotating electric machine can be provided at lower cost. 2 and 4 show the characteristics during the generator operation, the effects of the present invention can also be enjoyed in the motor operation. When the motor is in operation, the starting current and vibration at the time of starting can be reduced by reducing the distortion rate of the cogging torque and the induced electromotive force waveform.

  FIG. 6 is an explanatory view of a rotor structure showing another embodiment of the present invention. When the magnets 10 and 11 are housed in the slot 3, the slot 3 in which a slit 15 is formed between the magnets 10 and 11 is shown. It is one Example made into the shape. The slit 15 has the effect of reducing leakage magnetic flux generated between the magnets 10 and 11 even in the air (cavity) and increasing the use efficiency of the magnet, but further encloses a magnet fixing material such as resin or adhesive. Then, since the magnet fixing material penetrates to the gap between the magnets 10 and 11 and the rotor core 2, the magnets 10 and 11 and the rotor core 2 can be firmly fixed, and thus centrifugal force is increased particularly by high-speed rotation. This is effective in preventing deformation of the rotor core 2 and scattering of the magnets 10 and 11, and the reliability of the rotor 1 can be improved. Although the braking winding is not shown in FIG. 6, it goes without saying that the effect of this embodiment is effective even when the braking winding is present.

  As mentioned above, in each Example of this invention, the case where the flat shape was employ | adopted as a magnet shape was made into the example. Flat magnets are easy to manufacture and improve the base material utilization rate (yield) when manufacturing magnets, so magnet processing costs and material costs are lower than when arc-shaped magnets are used. There is an effect that can be done.

It is sectional drawing which shows the structure of one Example in the rotor of the permanent magnet type rotary electric machine which concerns on this invention. It is explanatory drawing of the rotary electric machine various characteristics when the circumferential direction angle | corner (theta) ₁ of a magnet is changed. It is sectional drawing which shows the structure of the other Example in the rotor of the permanent magnet type rotary electric machine which concerns on this invention. It is explanatory drawing of various characteristics of a rotary electric machine when changing angle (theta) ₂ which inclines a magnet to magnetic pole center position direction. It is explanatory drawing of the rotor structure which shows the other Example of this invention. It is explanatory drawing of the rotor structure which shows the other Example of this invention. It is explanatory drawing of the rotor structure by a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Rotor core, 3 ... Slot, 4 ... Braking winding, 10 ... N pole side permanent magnet, 11 ... S pole side permanent magnet, 15 ... Slit part, 20 ... Rotating shaft.

Claims (6)

A stator with a plurality of windings;
A rotor core fixed to a rotation shaft so as to be rotatable inside the stator;
A plurality of substantially parallel magnetized plate-shaped magnets housed in slots provided in the rotor core;
Among the plurality of magnets constituting one magnetic pole, the magnet is arranged such that the orientation of the magnet arranged on the magnetic pole end side is directed to the magnetic pole center position direction,
There are two poles,
The rotating electrical machine characterized in that the plurality of magnets constituting one magnetic pole is at least three.   2. The rotating electrical machine according to claim 1, wherein a circumferential angle of the plurality of magnets constituting the one magnetic pole is in an electric angle range of 150 to 165 degrees.   Among the plurality of magnets constituting the one magnetic pole, the arrangement of the magnets arranged on the magnetic pole end side is a point on the outer peripheral surface of the rotor core on a straight line passing through the rotation axis center and two points of the magnet center. 2. The rotating electrical machine according to claim 1, wherein the rotating electric machine is arranged so that an angle formed between a tangent line having a contact point and the magnet is in a range of 2 degrees to 6 degrees toward a magnetic pole center position. Among the plurality of magnets constituting the one magnetic pole, the long side of the magnet disposed on the magnetic pole end side,
A tangent line with a point on the outer peripheral surface of the rotor core on a straight line passing through the center of the rotation axis and the two points of the magnet center as a contact point,
An angle of 2 degrees to 6 degrees is formed on a straight line passing through two points of the rotation axis center and the magnetic pole center and in a direction in which the radially outward direction of the rotor core coincides with the orientation of the magnet. Item 2. The rotating electrical machine according to Item 1.   The rotating electrical machine according to claim 1, wherein the slot has a shape in which a slit is formed between the magnets.   The rotating electrical machine according to claim 1, wherein a magnet fixing material is enclosed in the slit portion.

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