JP2006115663A - Permanent magnet rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet rotor capable of improving total torque even if an increase in cost is suppressed as much as possible. <P>SOLUTION: The permanent magnet rotor 1 includes a rotor core 2 constituted by laminating silicon steel plates as many annular core materials. A plurality of magnet insertion holes 3 with an outer peripheral side opened are formed on the outer periphery of the rotary core 2 at a specified interval, allowing, for example, ferrite magnets 4 formed into an arcuate shape as a permanent magnet to be inserted thereinto to be fixed with an adhesive agent or the like. Furthermore, in the rotor 1, the portion where the ferrite magnets 4 are arranged is a magnetic recess (q axis) 1a where a flux is difficult to pass, and the core position between the ferrite magnets 4, 4 is a magnetic protrusion (d axis) 1b where the flux is easy to pass, wherein the magnetic recess 1a and the magnetic protrusion 1b are alternately formed in the peripheral direction at a specified interval. Consequently, when current is made to flow in a stator winding, the total torque combining a reluctance torque and a magnetic torque causes the rotor 1 to rotate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a permanent magnet rotor capable of improving rotational torque.

  FIG. 11 shows a cross-sectional view of the permanent magnet rotating electrical machine 100. In FIG. 11, a stator core 101 formed by laminating silicon steel plates formed in an annular shape has a plurality of slots at predetermined intervals. 101a is provided, and the stator winding 102 is accommodated in each slot 101a, and thus the stator 103 is configured. Further, on the inner peripheral side of the stator core 101, a rotor core 104 formed by laminating silicon steel plates formed in an annular shape is disposed. A plurality of magnet insertion holes 105 are provided at predetermined intervals on the outer peripheral portion of the rotor core 104, and permanent magnets 106 are inserted into the magnet insertion holes 105, thereby providing a permanent magnet rotor. 107 is configured.

  A moving magnetic pole is generated by passing a current through the stator winding 102, and torque is generated in the rotor 107 by the magnetic attraction force of the moving magnetic pole. High operating efficiency can be maintained by the operation principle.

  One of the factors contributing to the magnetic attraction force on the rotor 107 side is a magnetic force (magnet torque) generated by the permanent magnet 106. The stronger this magnetic force, the more the magnetic attraction force increases and improves the operation efficiency. At the same time, the output density can be increased. As such a permanent magnet, there is a rare earth sintered magnet having a high energy density. For example, when a ferrite magnet and a neodymium magnet that is one of rare earth sintered magnets are compared in terms of magnetic force, the magnetic force of the neodymium magnet is about three times that of the ferrite magnet in the same volume. Therefore, it is clear that the suction force makes a great difference. For this reason, neodymium magnets are generally used for high-power rotating machines. Subsequently, in terms of cost, ferrite magnets are very cheap because they are a kind of iron oxide, and neodymium magnets use rare metals, so they have a unit price of gram about 10 times that of ferrite magnets. For this reason, it is one of the factors that continually become a barrier to the spread of rare earth sintered magnets in rotating machines.

  Meanwhile, reluctance torque is another factor contributing to the magnetic attractive force. In general, the permanent magnet rotor 107 of the embedded magnet type embeds the permanent magnet 106 in the slot 105 of the rotor core 104, so that the permanent magnet 106 can be easily fixed and is connected to the stator core 101 existing on the outer peripheral side. The gap can be narrowed and the output density can be increased. Therefore, recently, by utilizing the salient pole structure of the permanent magnet rotor 107 of the embedded magnet type, the reluctance torque is actively used while retaining the power as the electromagnet of the energized stator winding 102. Attempts have also been made to improve torque. Here, the salient pole structure refers to a portion where the magnetic flux passes through the permanent magnet 106 as viewed from the stator 103 side (such as a magnetic convex portion that is difficult to pass the magnetic flux) and a permanent magnetic flux, as in the permanent magnet rotor 107. It refers to a structure having alternately portions that do not pass through the magnets 106 (magnetic recesses that are easy to pass magnetic flux passing between the permanent magnets 106).

  Considering the manufacturing cost of the permanent magnet rotating electrical machine 100, it is wise to increase the reluctance torque as much as possible and reduce the magnet torque by the increase, that is, reduce the amount of magnet used. In particular, a permanent magnet rotating electric machine using a rare earth sintered magnet is manufactured based on such a method. In addition, a permanent magnet rotating electric machine using a ferrite magnet is manufactured based on a method in which a weak magnet torque of a ferrite magnet is compensated by a reluctance torque.

  At present, a permanent magnet rotating electric machine that uses a total torque including a magnet torque and a reluctance torque as a generated torque is becoming mainstream.

Incidentally, Non-Patent Document 1 describes the proper use of the rotor shape depending on the degree of utilization of the reluctance torque, while corresponding to the operating characteristics of the rotating electrical machine. In this Non-Patent Document 1, these various rotor shapes are introduced, but since all the structures utilizing the reluctance torque completely embed a permanent magnet in the rotor, An iron core portion (see 104a in FIG. 11) exists on the outer peripheral side of the permanent magnet.
Tsuji and five others, “Development of a permanent magnet type reluctance motor for electric vehicles with excellent variable speed characteristics”, IEEJ Transactions D (Journal of Industrial Application), June 2003, Vol. 123, June, p.681-689

  According to the configuration of the prior art, the rotor 107 has the iron core portion 104a located on the outer peripheral side of the permanent magnet 106, so that part of the magnetic flux of the permanent magnet 106 is directed to the stator 1073 side at the iron core portion 104a. In other words, a part of the magnetic flux generated by the electromagnet on the stator 103 side is not directed toward the center of the rotor 107, resulting in a shortcut state. As a result, the magnetic flux leaks and the total torque decreases. There is.

  In order to solve such a problem, since the magnetic flux of the permanent magnet 106 is proportional to the width dimension in the circumferential direction of the permanent magnet 106, the width torque is increased to increase the magnet torque, or the permanent magnet 106 It is conceivable to increase the reluctance torque by widening the interval between the 106. However, for example, when the width dimension of the permanent magnet 106 is reduced, the reluctance torque increases, but the magnet torque as the permanent magnet 106 decreases. Therefore, in order to increase the total torque, the magnetic flux of the permanent magnet 106 is proportional to the thickness dimension of the permanent magnet 106, and therefore it is preferable to increase the radial thickness dimension of the permanent magnet 106. However, when the volume is increased by simply increasing the thickness without changing the width of the permanent magnet 106, a dilemma is caused in which an associated increase in cost occurs.

  This invention is made | formed in view of the said situation, The objective is to suppress the increase in cost as much as possible and to provide the permanent magnet rotor which can improve a total torque.

A permanent magnet rotor according to the present invention includes a rotor core, a plurality of magnet insertion holes provided on an outer peripheral portion of the rotor core, the outer peripheral side being opened, and a permanent magnet inserted into the magnet insertion hole. (Claim 1).
According to such a configuration, since there is no iron core portion located outside the permanent magnet in the rotor core, leakage of the magnetic flux by the permanent magnet and the magnetic flux by the electromagnet of the stator is prevented.

The permanent magnet rotor according to the present invention is characterized in that the permanent magnet is composed of a plurality of unit magnets having the same shape, and the unit magnets are stacked in the radial direction in the magnet insertion hole. (Claim 6).
In this case, one unit magnet is disposed on the outer peripheral side of the magnet insertion hole, and an iron block having the same shape is disposed in place of at least one of the remaining unit magnets. .

According to the present invention, the permanent magnet is composed of a plurality of unit magnets having different shapes, and the unit magnets are arranged in a radial direction in the magnet insertion hole. ).
In this case, one unit magnet is disposed on the outer peripheral side of the magnet insertion hole, and an iron block having the same shape is disposed in place of at least one of the remaining unit magnets. .

  According to such a configuration, the permanent magnet has a plurality of unit magnets, one unit magnet is arranged on the outer peripheral side of the magnet insertion hole, and iron of the same shape instead of at least one of the remaining unit magnets. By arranging blocks, a permanent magnet is configured by combining unit magnets and iron blocks according to the desired output, so a rotor that generates multiple outputs can be shared by a single rotor core. The manufacturing cost can be suppressed.

  According to the present invention, since there is no core portion located on the outer peripheral side of the permanent magnet in the rotor core, leakage of magnetic flux does not occur, and the magnetic flux of the permanent magnet and the electromagnet can be used efficiently. The total torque can be improved while suppressing the cost increase as much as possible.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIG.
In FIG. 1, a permanent magnet rotor (hereinafter simply referred to as a rotor) 1 has a rotor core 2 formed by laminating silicon steel plates as a large number of annular cores. A plurality (four in the figure) of magnet insertion holes 3 are formed on the outer peripheral portion of the rotor core 2 and open on the outer peripheral side with a predetermined interval. As a magnet, for example, a ferrite magnet 4 formed in a fan shape is inserted and fixed by adhesion or the like.

  Further, in the rotor 1, the portion where the ferrite magnet 4 is disposed is a magnetic recess (q-axis) 1 a in which the magnetic flux due to the electromagnet of the stator (not shown) is difficult to pass, and the iron core portion between the ferrite magnets 4 and 4 Magnetic convex portions (d-axis) 1b that are easy to pass through, and these magnetic concave portions 1a and magnetic convex portions 1b are alternately formed with a predetermined interval in the circumferential direction.

  Now, the rotating shaft, the rotor core 2 and the end plate (not shown) are integrated to assemble the rotor 1. In this way, the rotor 1 is arranged in a stator on which a stator winding (not shown) is provided, so that a permanent magnet type reluctance type rotating electrical machine is configured. Then, by passing an electric current through the stator winding, the rotor 1 is provided between the ferrite magnet 4 arranged so as to be substantially flush with the outer peripheral surface of the rotor core 2 and the moving magnetic pole of the stator. Magnet torque is generated by the magnetic attractive force and the magnetic repulsive force generated in the magnetic field. In addition, since the rotor 1 is formed with a magnetic concave portion (q axis) 1a and a magnetic convex portion (d axis) 1b, a gap portion on the magnetic convex portion 1b and the magnetic concave portion 1a. Thus, the magnetic energy stored by passing a current through the stator winding is different, and reluctance torque is generated by the change in the magnetic energy. The rotor 1 is rotated by a total torque obtained by combining the magnet torque and the reluctance torque.

  According to such a configuration, the outer periphery of the rotor core 2 is formed with a plurality of magnet insertion holes 3 having a predetermined interval and opened on the outer periphery, and each magnet insertion hole 3 has a permanent opening. A ferrite magnet 4 is inserted as a magnet. There is no core part (corresponding to 104a in FIG. 11) of the rotor core 2 on the outer peripheral side of the ferrite magnet 4, and the magnetic flux of the ferrite magnet 4 and the reluctance magnetic flux (magnetic flux by the electromagnet of the stator) are Leakage is suppressed by a shortcut that passes through. Thereby, the magnetic flux of the original ferrite magnet 4 is effectively used, and the reluctance magnetic flux is not changed because the width-direction dimension of the ferrite magnet 4 is not changed. Therefore, without reducing the reluctance magnetic flux, it is possible to improve the magnet torque while suppressing the increase in the volume of the magnet and suppressing the cost increase, thereby improving the total torque of the magnet torque and the reluctance torque.

(Second embodiment)
FIG. 2 shows a second embodiment of the present invention, which is different from the first embodiment in that the outer peripheral portion of the rotor core 5 that changes to the rotor core 2 is open at a predetermined interval on the outer periphery. A plurality of magnet insertion hole portions 6 are formed, and the magnet insertion hole portion 6 is provided with a curved retaining portion 7 that makes the width of the opening portion small. For example, a ferrite magnet 8 formed in the same shape as the magnet insertion hole 6 is inserted into the magnet insertion hole 6 as a permanent magnet. Other configurations are the same as those of the first embodiment.

  According to such a configuration, the magnet insertion hole 6 is provided with the retaining portion 7 formed in a curved shape so that the width of the opening is small, and the magnet insertion hole 6 has the magnet Since the ferrite magnet 8 formed in the same shape as the insertion hole 6 is inserted, even if current flows through the stator winding, magnet torque and reluctance torque are generated and the rotor 1 rotates. It is possible to prevent the ferrite magnet 8 from coming out of the magnet insertion hole 6. Needless to say, the same effect as in the above embodiment can be obtained.

(Third embodiment)
FIG. 3 shows a third embodiment of the present invention. The difference from the second embodiment is that a chip is placed inside the outer end of the magnet insertion hole 6 instead of the curved retaining portion 7. An overhanging chip-shaped retaining portion 9 is provided. Then, the ferrite magnet 8 is inserted into the magnet insertion hole 6, and the retaining part 9 is deformed by applying a pressing force to the retaining part 9 by punching or pressing, etc., and the retaining part 9 is prevented from coming off, The rotor core 5 is restrained. Other configurations are the same as those of the second embodiment.

  According to such a configuration, since the ferrite magnet 8 is constrained by the chip-shaped retaining portion 9, it may be damaged by vibration or collapse of the balance of the center of gravity during transportation during operation of the rotating electrical machine or during operation of the rotating electrical machine. The risk of occurrence of vibration due to eccentricity can be prevented, and the unbalance of the rotor 1 can be suppressed and the total torque can be maximized. Needless to say, the same effects as those of the second embodiment can be obtained.

(Fourth embodiment)
FIG. 4 shows a fourth embodiment of the present invention. The same parts as those in FIG. 3 are denoted by the same reference numerals, and different points will be described below. In this embodiment, the case where the retaining portion 9 is cured is shown, and examples of the curing method include laser quenching, carburizing treatment, nitriding treatment, and the like. The strength can be improved by increasing the curing of the hatched portion. In general, electrical steel sheets have a very soft material. To exhibit magnetic properties, it must be soft in strength, but to overcome the centrifugal force of the magnet, it must have a high yield point or hard. It is very difficult to make these contradictory characteristics compatible, and the materials are limited. In addition, an expensive third element is added to the composition, and the electromagnetic steel sheet itself is generally high.

  According to this, a magnetically soft material, ie, a low strength material is used, the magnetic resistance is lowered to improve the flow of magnetic flux, the iron loss is reduced, and only the retaining portion 9 requiring high strength is cured. And strength is improved. When the iron core part between the magnets becomes narrow or the retaining part 9 has a large bend to maintain strength, stress concentration occurs in the part, and if a part exceeding the yield point comes out, during operation Although the iron core portion may be broken due to metal fatigue, the magnet may scatter and the rotating electrical machine may be damaged, but the strength can be improved by hardening the retaining portion.

(Fifth embodiment)
FIG. 5 shows a fifth embodiment of the present invention, and the differences from the second embodiment will be described. Instead of the ferrite magnet 8 as a permanent magnet, a ferrite magnet 10 is used. The ferrite magnet 10 has a taper whose width dimension is gradually reduced toward the bottom side tip, and the tip side is the circumference of the rotor core 5. As a plurality of unit magnets formed so as to be aligned on the same plane (kamaboko shape), for example, two ferrite unit magnets 10a and 10a are configured. One ferrite magnet 10 is formed by matching the bottom portions of the ferrite unit magnets 10a and 10a. Further, the rotor core 5 is formed with a magnet insertion hole 11 formed in the same shape as the ferrite magnet 10 in which the ferrite unit magnets 10a and 10a are stacked in the radial direction. In addition, a tapered retaining portion 12 that matches the tapered surface of the ferrite unit magnet 10a is provided. Then, after the ferrite magnet 10 is inserted and arranged, it is magnetized. Other configurations are the same as those of the second embodiment.

  According to such a configuration, two ferrite unit magnets 10a and 10a as a plurality formed in the same shape are stacked in the radial direction of the rotor core 2 in the magnet insertion hole 11, so that a rotating machine is required. Even if two unit magnets are used to generate the magnet magnetic flux, the cost can be reduced compared with the case where two magnets of different shapes are prepared, and the first and second embodiments can be reduced. Similar effects can be obtained.

(Sixth embodiment)
FIG. 6 shows a sixth embodiment of the present invention, and the differences from the first embodiment will be described. Instead of using the ferrite magnet 4 as a permanent magnet, a ferrite magnet 13 is used. The ferrite magnet 13 includes a plurality of ferrite unit magnets 13a and ferrite unit magnets 13b as a plurality, and the ferrite unit magnet 13a has a taper whose width dimension is gradually reduced from the magnet bottom side toward the tip. In addition, the upper end side is formed to be flush with the circumference of the rotor 1 (kamaboko shape), and the ferrite unit magnet 13b is formed in a rectangular parallelepiped shape having a long side width dimension smaller than the bottom side width of the ferrite unit magnet 13a. Yes. Further, in the magnet insertion hole 14 of the rotor core 2, the ferrite unit magnet 13a is disposed on the outer peripheral side in the radial direction, and the ferrite unit magnet 13b is stacked and disposed on the inner side. The magnet insertion hole 14 is provided with a tapered retaining portion 15 that matches the tapered surface of the ferrite unit magnet 13a. The ferrite magnet 13 is magnetized after being inserted into the magnet insertion hole 14 and disposed. Other configurations are the same as those of the first embodiment.

  According to such a configuration, a plurality of ferrite unit magnets 13a and 13b are formed as a plurality of different shapes, and the rectangular parallelepiped ferrite unit magnets 13b are stacked on the radially inner peripheral side of the kamaboko-shaped ferrite unit magnet 13a. Has been placed. For example, when the rotor 1 is reduced in size, it becomes extremely narrow as the core portion of the rotor core 2 existing between the permanent magnets 13 becomes the inner peripheral side. Since the reluctance magnetic flux flows because the iron core portion is a magnetic convex portion (d-axis), if it becomes too narrow, there is a possibility that magnetic saturation occurs and the reluctance magnetic flux is reduced, resulting in a decrease in magnet torque. Even if it increases, the reluctance torque may further decrease and the total torque may decrease. However, since the ferrite unit magnet 13b arranged on the inner peripheral side is formed smaller in width than the ferrite unit magnet 13a so as not to magnetically saturate the iron core portion existing between the ferrite unit magnets 13b, the magnet torque is reduced. Therefore, it is possible to suppress a decrease in reluctance torque due to magnetic saturation of the iron core portion, and to generate a large total torque. Furthermore, since the ferrite unit magnet 13b has a rectangular shape, it can be manufactured at low cost. Other effects similar to those of the first embodiment can be obtained.

(Seventh embodiment)
The seventh embodiment of the present invention will be described below.
In a permanent magnet reluctance type rotating electrical machine, torque is generally generated by the action of a current flowing in a stator winding and a magnet magnetic flux, but a magnetic field due to the current is applied in a radial direction toward the center of the rotor magnetic pole. This magnetic field is applied to the magnet in the direction of demagnetization, that is, the direction of demagnetization. Therefore, the magnet needs to have a coercive force or thickness that can overcome the demagnetization. In the case of a permanent magnet that has a shape as shown in FIG. 7 and is not divided, the magnet thickness decreases as it approaches the both ends from the center. The demagnetizing field due to the current flowing through the stator winding is also applied to some extent on both ends of the permanent magnet. The both end portions of the permanent magnet will be demagnetized. Even if there is a sufficient magnet thickness, both ends of the magnet are in contact with the core part of the rotor core, so even if the amount of demagnetizing field applied to the permanent magnet part is small, it is applied toward the core part. There is a possibility that the demagnetizing field component may be applied through a narrow thickness portion of the permanent magnet, which may cause unexpected demagnetization. Therefore, in order to prevent demagnetization, the magnet thickness can be designed based on the demagnetizing fields at both ends, but as a result, the amount of magnet is not sufficient to obtain a torque exceeding a predetermined value. It is an economy.

Therefore, in the seventh embodiment of the present invention, demagnetization is suppressed as follows.
FIG. 7 shows a seventh embodiment of the present invention, and different points from the second embodiment will be described. In the second embodiment, the ferrite magnet 8 is used, but instead, as a permanent magnet, for example, a ferrite magnet 16 is composed of a central magnet 16a and side magnets 16b and 16b arranged on both sides in the circumferential direction. It was set as the structure divided and used.

  The central magnet 16a is formed such that both sides in the circumferential direction are tapered such that the width dimension gradually decreases toward the outer circumference, and the magnetization direction is magnetized in the radial direction. The side magnet 16b is formed in a tapered shape whose width dimension gradually increases toward the outer periphery, and coincides with both sides of the central magnet 16a in the circumferential direction, and the magnetization direction is magnetized toward the circumferential direction. Are arranged. Magnetization of every magnet is magnetized so as to have the same polarity (NorS pole) toward the center of the magnetic pole. That is, a magnet different from the central magnet 16a disposed in the center of the magnetic pole is provided as the side magnet 16b at both ends where the demagnetization of the magnet is severe.

  The magnetization direction of the side magnet 16b is arranged in the circumferential direction. The demagnetization of the magnet depends on the magnitude of the demagnetizing field component applied to the magnetization direction axis. Therefore, the magnet is not demagnetized by the demagnetizing field component applied at right angles to the magnetization direction. That is, no matter how narrow the side magnet 16b is, the demagnetizing field is applied in a direction perpendicular to the magnetization, so that the side magnet 16b is not demagnetized. Further, since the magnetic flux generated from the side magnet 16b whose magnetization is directed in the circumferential direction flows toward the center of the magnetic pole, it can be synergistic with the magnetic flux generated by the central magnet 16a. Accordingly, the thickness of the central magnet 16a can be determined without considering the demagnetization of the side magnets 16b arranged at both ends of the central magnet 16a. A magnet can be placed. Further, since the central magnet 16a and the side magnet 16b are formed in a tapered shape, the side magnet 16b serves to hold down the central magnet 16a so that the central magnet 16a does not scatter due to centrifugal force, and the side magnet 16b has a centrifugal force. Therefore, scattering is prevented by the retaining portion 7 so as not to scatter. A reduction in total torque due to demagnetization can be suppressed, and the same effect as in the above embodiment can be obtained.

(Eighth embodiment)
8 and 9 show an eighth embodiment of the present invention. The difference from the seventh embodiment is that instead of the central magnet 16a and the side magnet 16b formed of ferrite magnets, the central magnet 17a is used. Is formed of a high energy magnet, and the side magnet 17b is formed of a high coercive force magnet. Furthermore, the magnetization directions of the center magnet 17a and the side magnet 17b are magnetized in the radial direction. Other configurations are the same as those of the seventh embodiment.

  According to such a configuration, since both ends of the magnet may be vulnerable to demagnetization as described above, the side magnets 17b arranged at both ends are made of a high coercivity magnet having excellent demagnetization performance. As the central magnet 17a used for inducing a large torque at the center of the magnetic pole, a high energy magnet having a large magnetic flux generation amount is used, so that it is not necessary to consider the demagnetization of the side magnet 17b and the amount of the magnet is small. A predetermined torque can be exhibited.

(Modification)
For example, the center magnet 17a is formed of a ferrite magnet having a large volume as a high energy magnet, and the side magnet 17b is formed of a neodymium magnet having a high energy and high coercivity as a rare earth magnet.

FIG. 9 shows a result of comparison of characteristics between a ferrite magnet and a rare earth magnet. In FIG. 9, the ferrite magnet is a ferrite magnet, the magnetic flux density is 0.45 (T), and the coercive force is 450 (KA / m). The density is 4.7 (g / cm ³ ) and the gram unit price is 0.8 (yen). The rare earth magnet is a neodymium magnet whose characteristics are changed by an additive element, and is classified into a high energy neodymium magnet A and a high coercivity neodymium magnet B. The high coercivity neodymium magnet B has an improved coercive force by adding elements such as Co, Tb and Dy as an additive element in addition to the main component, and has a magnetic flux density of 1.30 (T) and a coercive force. The density is 2800 (KA / m), the density is 7.5 (g / cm ³ ), and the gram unit price is 13 (yen). Further, the addition of the additive element (impurities) is reduced to improve the purity of so-called neodymium is a high energy neodymium magnet A, and the high energy neodymium magnet has a magnetic flux density of 1.43 (T), The coercive force is 1200 (KA / m), the density is 7.5 (g / cm ³ ), and the gram unit price is 12 (yen). In addition, as a high coercive force magnet, there is a SmCo (samarium cobalt) magnet, a magnetic flux density is 1.00 (T), a coercive force is 2500 or more (KA / m), and a density is 8.4 (g / cm ^3). ) Unit price of gram is 25 (yen).

  According to such a configuration, as is clear from FIG. 9, the high-energy neodymium magnet has a magnetic flux generating force (magnetic flux density) that is about three times that of the ferrite magnet, and a demagnetization resistance (about three times) Therefore, it corresponds to a ferrite magnet having a volume about three times as large. Moreover, even if the ferrite magnet occupies a large volume as a main magnet compared with a neodymium magnet, since the density is small, it does not become so much weight.

  Therefore, the central magnet 17a can be made relatively large in magnet shape and can be increased in thickness. Therefore, even if it is a ferrite magnet with low energy, the amount of magnetic flux can be earned by heat, and the main magnet is not greatly reduced. Since the ferrite magnet does not increase in weight as compared with the rare earth magnet, the restraining force against scattering due to the centrifugal force generated during the operation of the rotating machine can be reduced, and the problem of mechanical strength can be alleviated. Furthermore, since the unit price in grams is one digit or more cheaper, a rotating electrical machine can be manufactured at low cost.

  The side magnet 17b is smaller in volume than the central magnet 17a, but is a neodymium magnet having high energy, so that it generates a magnetic flux equivalent to that of a ferrite magnet, but has a dynamic volume of ferrite. Since it has a high coercive force as compared with a magnet, it is not demagnetized even if the thickness is small.

  Therefore, demagnetization can be suppressed and predetermined total torque can be obtained at low cost while efficiently preventing scattering of the magnet. Furthermore, the same effect as in the above embodiment can be obtained. When the central magnet 17a is set to a small volume, the neodymium magnet A may be used for the central magnet 17a, and the neodymium magnet B or SmCo magnet may be used for the side magnet 17b.

(Ninth embodiment)
FIG. 10 shows a ninth embodiment of the present invention.
In the permanent magnet reluctance type rotating electrical machine, since the magnetization of the permanent magnet is generally directed in the radial direction, the magnet in the center of the magnetic pole generates a magnetic flux that induces a large torque. However, a part of the magnetic flux flows in the iron core portion existing between the magnets, and does not interlink with the stator windings, and becomes a so-called leakage magnetic flux that does not contribute to the magnet torque.

Therefore, the configuration for suppressing the leakage magnetic flux is as follows.
FIG. 10 shows a ninth embodiment of the present invention, and different points from the seventh embodiment will be described. The difference from the seventh embodiment is that, instead of the side magnet 16b, a non-magnetic material such as a ceramic body, which is a high resistivity material, and a spacing piece 16c such as a resin block are used. The spacing piece 16c is provided with a large taper on the outer peripheral side in accordance with the taper of the central magnet 16a.

  According to such a configuration, the center piece magnet 16a and the core portion of the rotor core 5 are separated from each other by the spacing piece 16c made of a nonmagnetic material so that the magnetic flux does not leak into the core portion. . Since the spacing piece 16c has an effect of not passing the magnetic flux, all the magnetic flux of the central magnet 16a is linked to the stator winding, which contributes to improvement of the magnet torque. Further, since the spacing piece 16c and the central magnet 16a are tapered, the spacing piece 16c plays a role of pressing down so that the central magnet 16a is not scattered by centrifugal force. Therefore, it is possible to obtain a strong magnet torque by suppressing the leakage of the magnetic flux of the central magnet 16a, and to obtain the same effect as in the above embodiment.

(Other examples)
The present invention is not limited to the embodiments described above and shown in the drawings, and can be expanded or modified as follows.
In the first embodiment, the ferrite magnet 3 is formed in a circular arc shape as a permanent magnet, but the ferrite magnet may be formed in a kamaboko shape.
In the first, second, third, and fourth embodiments, the ferrite magnet 3 is used as the permanent magnet. However, a neodymium magnet (either high energy or high coercive force may be used) may be used as the permanent magnet. Good.

  In the above-described embodiment, the retaining portions 7 and 9 are formed in a curved shape such that the width dimension of the opening portion of the magnet insertion hole 6 is small or a chip shape protruding from the outer peripheral side end of the magnet insertion hole 6. However, the retaining portions 7 and 9 may be formed in a tapered shape in which the width of the open portion of the magnet insertion hole 6 is sequentially reduced.

In the fifth embodiment, the bottom portion of the ferrite unit magnet 10a is aligned and stacked in the radial direction. However, the upper end portion of the ferrite unit magnet 10a existing on the inner peripheral side faces the outer peripheral direction. In this case, the shape of the rotor core 2 is complicated, but only one retaining portion 12 during operation prevents stress from being concentrated by the centrifugal force applied to the ferrite unit magnet 10a. Even if this is not possible, the stress concentration during rotation can be dispersed by the two retaining portions, and a stable and reliable operation can be realized.
In the fifth and sixth embodiments, two unit magnets are used as the plurality of unit magnets, but any number of unit magnets may be used as long as there are two or more.
In the fifth or sixth embodiment, instead of arranging the ferrite unit magnets 10a or 13b on the inner peripheral side of the rotor core 5 or 2, an iron block may be inserted.

Here, the magnet torque increases as the number of unit magnets inserted on the inner peripheral side among the ferrite unit magnets 10 or 13 inserted into the plurality of magnet insertion holes 11 or 4 provided in the rotor core 5 or 2 increases. It is disadvantageous to attach a magnet torque of a predetermined value or more to the magnets 10 and 13 from the viewpoint of suppressing an increase in cost. Therefore, when it is not necessary to arrange the ferrite unit magnets 10a or 13b, a gap is formed and the flow of the reluctance magnetic flux is obstructed. However, by inserting and arranging an iron block in the gap, the magnetic circuit Can be formed so as not to obstruct the flow of the magnetic flux. As a result, the rotor can be shared over a relatively wide range of output torque, and the output torque can be adjusted by changing the number of ferrite unit magnets 10a and 13a inserted.
In the above embodiment, the retaining portions 7, 12, 15 may be cured.

Sectional drawing of the rotor which shows 1st Example of this invention FIG. 1 equivalent view showing a second embodiment of the present invention. FIG. 1 equivalent view showing a third embodiment of the present invention. FIG. 1 equivalent view showing a fourth embodiment of the present invention. FIG. 1 equivalent view showing a fifth embodiment of the present invention. FIG. 1 equivalent view showing a sixth embodiment of the present invention. FIG. 1 equivalent diagram showing a seventh embodiment of the present invention FIG. 1 equivalent diagram showing an eighth embodiment of the present invention. Characteristics of magnet FIG. 1 equivalent view showing a ninth embodiment of the present invention. Sectional view of a rotating electrical machine showing conventional technology

Explanation of symbols

  In the drawings, 1 is a stator core, 1a is a magnetic recess, 1b is a magnetic projection, 2, 5 is a rotor core, 3, 6, 11, and 14 are magnet insertion holes, and 4, 10, and 13 are ferrites. Magnets 7, 9, 12, 15 are retaining portions, 8, 16 are ferrite magnets, 10a, 13a, 13b are ferrite unit magnets, 16a, 17a are central magnets, 16b, 17b are side magnets, and 16c is a spacing piece. Indicates.

Claims (15)

The rotor core,
A plurality of magnet insertion holes provided on the outer peripheral portion of the rotor core, the outer peripheral side being opened; and
A permanent magnet rotor comprising a permanent magnet inserted into the magnet insertion hole.   The permanent magnet rotor according to claim 1, wherein the magnet insertion hole includes a retaining portion that prevents the permanent magnet from being pulled out from the open portion.   The permanent magnet rotor according to claim 2, wherein the retaining portion has a curved shape.   The permanent magnet rotor according to claim 2, wherein the retaining portion has a tapered shape.   The permanent magnet rotor according to claim 2, wherein the retaining portion has a chip shape. The permanent magnet is composed of a plurality of unit magnets having the same shape,
The permanent magnet rotor according to any one of claims 1 to 5, wherein the unit magnets are stacked in the radial direction in the magnet insertion hole. The permanent magnet is composed of a plurality of unit magnets having different shapes,
The permanent magnet rotor according to any one of claims 1 to 5, wherein the unit magnets are arranged in the radial direction in the magnet insertion hole. One unit magnet is disposed on the outer peripheral side of the magnet insertion hole,
The permanent magnet rotor according to claim 6 or 7, wherein an iron block having the same shape is arranged instead of at least one of the remaining unit magnets.   The permanent magnet rotor according to claim 2, wherein the retaining portion is hardened.   The permanent magnet rotor according to any one of claims 1 to 5, wherein the permanent magnet is divided into three parts: a center magnet and side magnets on both sides in the circumferential direction. The central magnet is formed in a tapered shape in which both side portions in the circumferential direction become smaller as the width dimension goes toward the outer circumference,
The permanent magnet rotor according to claim 10, wherein the side magnets are formed in a reverse taper shape that matches both sides in the circumferential direction of the central magnet. In the central magnet, the magnetization direction is set to the radial direction,
The permanent magnet rotor according to claim 10 or 11, wherein the side magnet has a magnetization direction set in a circumferential direction. The central magnet is a high energy magnet,
The permanent magnet rotor according to claim 10, wherein the side magnet is a high coercive force magnet. The central magnet is a ferrite magnet,
The permanent magnet rotor according to claim 10, wherein the side magnet is a rare earth magnet. The permanent magnet rotor according to any one of claims 1 to 5, wherein the permanent magnet includes a central magnet and non-magnetic spacing pieces on both sides in the circumferential direction.

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