JP2014087075A - Rotor of embedded magnet synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a neodymium magnet having a low dysprosium content for a rotor core having centrifugal force resistance strength.SOLUTION: A rotor of an embedded magnet synchronous motor comprises a rotor core 31 in which a magnetic steel plate 12 and a non-ferromagnetic metal plate 13 are laminated in a hybrid structure. A neodymium magnet is held only by the non-ferromagnetic metal plate 13 formed so as to be wide from an outer periphery, have high tensile strength and to be projected in magnet embedding holes 18 and 19. A magnetic flux of a reverse polarity magnetic field due to an armature current is leaked in magnetic-flux short-circuit prevention holes 24 and 25 formed long in a radial direction regardless of a frequency and without heat dissipation, allowing a high frequency component to be attenuated in metal plates 36 and 37 molded so as to be bent according to unevenness inside a magnetic pole head core 28 to suppress the reverse polarity magnetic field and a temperature rise in the neodymium magnet.

Description

The present invention relates to a rotor of an embedded magnet synchronous motor.

Permanent magnets are embedded in each magnetic pole of a rotor on which magnetic steel plates (magnetic steel plates) are laminated, and an embedded magnet synchronous motor that uses reluctance torque in addition to magnet torque (also known as embedded magnet synchronous motor or IPM motor) ) Is used in hybrid vehicles and electric vehicles, and is disclosed in Non-Patent Document 1 and Patent Document 1.

A conventional embedded magnet synchronous motor shown in FIG. 16 has a neodymium magnet (NdFeB-based sintered magnet) 2 shallowly embedded in a V shape in a rotor core 1 formed by laminating magnetic steel plates, and is radially Since there is little leakage of the magnetic flux in the same direction due to the reverse magnetic field due to the armature current in the shallow magnetic flux short-circuit prevention hole 3, the bridge portion 5 magnetically saturated with the magnetic flux of the neodymium magnet in advance, and the radial bridge portion 6, Many are added to the neodymium magnet 2 and the temperature rise due to eddy current loss also increases. Further, since a permeance coefficient is reduced by forming a punching gap between the neodymium magnet 2 and the rotor core 1, a neodymium magnet having a large coercive force Hcj is required to ensure the heat resistance of the neodymium magnet. The

The embedded magnet synchronous motor can cope with a high rotational speed by the magnetic flux weakening control. Increasing the width of the bridge portion 5 and the radial bridge portion 6 in order to provide a centrifugal strength strength against a high rotational speed increases the magnetic flux leakage of the neodymium magnet and causes a problem that the magnet torque decreases.

In hybrid vehicles, it is essential not to cause irreversible demagnetization in neodymium magnets even in a temperature environment of about 200 degrees Celsius due to heat from the engine, copper loss and iron loss in the stator and rotor. Become. In order to provide a large coercive force Hcj for the heat resistance of the neodymium magnet, a neodymium magnet having a heavy rare earth element dysprosium (Dy) content of about 8 wt% (weight percent) to about 10 wt% is used. However, the residual magnetic flux density Br decreases, and the production area and availability are restricted, so that expensive dysprosium is often used.

In order to avoid dysprosium, a terbium (Tb) -added neodymium magnet that exhibits substantially the same heat resistance and magnetic property changes as dysprosium can be used. Terbium is a rarer resource than dysprosium and overlaps with localities. In other cases, samarium-cobalt magnets may be used. Samarium-cobalt magnets are excellent in heat resistance, change in magnetic properties with temperature is small, and can have an energy product similar to neodymium magnets with high dysprosium content by increasing the iron content. Samarium (Sm) has less resources than neodymium. Cobalt (Co) is more expensive than iron (Fe).

A configuration for imparting centrifugal force resistance is disclosed in Patent Document 2. Permanent magnets inserted into magnet holes (magnet embedding holes) having continuous holes on both sides in the circumferential direction are laminated on steel plates of high-strength members and soft magnetic materials (magnetic steel plates). , Mainly kept from centrifugal force with high strength steel plate.

When steel plates of different materials are laminated and each other's steel plates are firmly fixed by bonding or mechanical tightening, the strain stress due to the difference in linear expansion at the time of thermal change increases, and the magnetic properties of the magnetic steel plate deteriorate or rotate. The child may be destroyed. Also, if the steel plates are not firmly fixed and can be displaced, the positional relationship of the outer peripheral side ends of the mutual magnet embedding holes is due to differences in expansion due to temperature changes, mechanical and assembly tolerances, etc. If not held, the high-strength member does not hit the permanent magnet and does not contribute to holding the permanent magnet from the centrifugal force. If the high-strength member is held by a steel plate made of a soft magnetic material, a problem arises in the strength against centrifugal force.

Patent Document 3 discloses a configuration that balances magnetic flux leakage of a permanent magnet in a rotor core and anti-centrifugal strength (rigid strength). A first magnetic steel plate having a narrow bridge portion formed by punching a short-circuit preventing portion between magnetic poles, and a second magnetic steel plate having a wide annular connecting portion formed without punching the short-circuit preventing portion. Are alternately stacked at a predetermined rate. Since the second magnetic steel plate alone is strong in centrifugal force, the overall centrifugal force strength is not necessarily increased.

Patent Document 4 discloses a method that plays a role of anti-centrifugal force with only a high-strength material and reduces magnetic flux leakage from a permanent magnet. The magnetic pole head core outside the permanent magnet is separated from the adjacent magnetic pole head core, both structurally and magnetically, and is connected to each other through a plurality of pins penetrating in the stacking direction of the magnetic pole head core. Along with the permanent magnet of the magnetic pole, it is fixed and supported by a plurality of high strength material portions. Although it is advantageous to reduce the magnetic flux leakage of the permanent magnet, since the breaking strength is weaker than the tensile strength, the structure held by the pin has a low anti-centrifugal strength and is not suitable for high rotational speed applications.

In a reluctance motor that does not use a permanent magnet, a rotor (rotor) of an electric motor that can withstand centrifugal force at a high rotational speed is disclosed in Patent Document 5. A non-magnetic plate is disposed between magnetic steel plates that are stacked and fitted with a plurality of uneven portions of a divided magnetic path, and each divided magnetic path of the rotor is ejected by centrifugal force by surface-bonding each other. Hold down. A non-magnetic metal plate such as austenitic stainless steel is used, and a magnetic steel plate has a plurality of divided magnetic paths separated in the radial direction to facilitate the flow of q-axis magnetic flux generated by the q-axis component of the armature current. However, when the operating temperature range is large due to strong adhesion to the magnetic steel sheet, the strain stress due to the difference in linear expansion in the direction almost perpendicular to the diameter is very large, which causes deterioration and destruction of magnetic properties. There is a possibility.

As shown in Non-Patent Documents 2 and 3, it was reported that the coercive force Hcj of about 1.6 MA / m (20 kOe) was secured by greatly reducing the grain refinement and grain interface control without adding dysprosium. Has been. However, in a hybrid vehicle exposed to a high temperature environment, there is no guarantee that it can withstand irreversible demagnetization simply by replacing the neodymium magnet with the conventional rotor configuration as shown in FIG.

Patent Document 6 discloses a method of providing a nonmagnetic portion (corresponding to a magnetic flux short-circuit prevention hole) between the outer periphery of a rotor core (rotor core) and a permanent magnet to suppress demagnetization that occurs at the end of the permanent magnet through demagnetization. Has been. In order to greatly reduce the reverse polarity magnetic field in the direction opposite to the magnetization magnetization applied to the permanent magnet, it is necessary to increase leakage with a gap that is long in the radial direction and narrow to some extent. In addition, securing the strength of centrifugal force that can cope with the increase in the mass of the magnetic pole head core increases the leakage of magnetic flux of the permanent magnet and causes a decrease in magnet torque.

Patent Document 7 discloses a configuration in which conductive plates are disposed in close contact with upper and lower sides of a permanent magnet, and an applied magnetic field is canceled by an induced magnetic field generated by an induced current of the conductive plate. Two fixed magnetic magnets and a variable magnetic magnet are embedded in each magnetic pole of the rotor core (core), and conductive plates are arranged above and below the fixed magnetic magnet. When the magnetic field due to the magnetizing current of the variable magnetic magnet penetrates the conductive plate, an induced current flows through the conductive plate, and a magnetic field is generated. This magnetic field cancels out the magnetic field generated by the magnetizing current passing through the fixed magnetic magnet, concentrates the magnetic field generated by the magnetizing current on the variable magnetic magnet, and efficiently magnetizes the magnetic field. It does not attenuate the reverse polarity magnetic field due to the armature current of the stator in the direction opposite to the magnetization direction of the permanent magnet.

There is a method in which a rotor and a stator, which are enclosed in a case and closed from outside air, are directly cooled by an air flow. In Patent Document 8, air is circulated through a ventilation hole penetrating both the rotor and the stator. In claim 9, air is circulated through a heat exchanger provided outside and the inside of the rotor.

In order to suppress rattling of the permanent magnet, Patent Document 10 discloses a method of disposing a leaf spring between the inner magnetic pole surface of the permanent magnet and the inner peripheral surface of the magnet support hole (magnet embedding hole). . Since heat dissipation and permeance coefficient are not taken into account, no effort has been made to increase the contact area with a soft magnetic leaf spring and reduce the magnetic gap.

Since the shallow portion of the permanent magnet embedded in the rotor core is not irreversibly demagnetized by the local magnetic field due to the armature current, the shallowly embedded portion of the permanent magnet is inclined with respect to the thickness direction as in Patent Document 11. There are a configuration for forming anisotropy and a method for increasing the magnet thickness as in Patent Document 12. In either method, a necessary portion of the permanent magnet embedded in each magnetic pole is effectively given a high coercive force, but the effect is small and the configuration becomes complicated.

Patent Document 13 discloses a configuration that reduces eddy current loss in a permanent magnet that is shallowly embedded in a rotor core. The cross-sectional area is reduced by changing the width according to the embedded depth to suppress eddy current loss and the resulting heat generation, but it is difficult to manufacture due to limitations in reducing the cross-sectional area of the magnet. There is little effect.

JP 2006-238553 A JP 2010-035264 A JP 2001-157396 A US4469970 Japanese Patent Laid-Open No. 9-191618 JP 2000-050543 A JP 2010-148179 A Japanese Patent Laid-Open No. 11-146585 JP 2008-125234 A JP 2004-357418 A JP 2009-254143 A JP 2009-053240 A US6703743B2

TOYOTA Technical Review Vol. 54 No. 1 Aug. 2005 S. Sugimoto: the 21st Int. Works on Rare Earth Permanent Magnet & ther Applications, (2010.9.1 Bled-Slovenia) C. Misima et al. : Proc. the 21st Int. Works on Rare Earth Permanent Magnets & ther Applications, (Bled-Slovenia) ed. S. Kobe, P .; T.A. McGunenes, pp. 253-256 (2010)

The main problem of the rotor of the interior permanent magnet synchronous motor of the present invention is that the rotor core having a hybrid structure in which magnetic steel plates and non-ferromagnetic metal plates are alternately laminated has a high tensile strength at the wide outer peripheral portion. By holding a neodymium magnet (rare earth magnet) on which a centrifugal force acts only by a magnetic metal plate, it has a large centrifugal strength strength, and by using a plurality of means based on the centrifugal strength strength, a neodymium magnet (rare earth) The reverse polarity magnetic field due to the armature current applied to the magnet) is reduced, and the temperature rise of the neodymium magnet (rare earth magnet) is suppressed.

The magnetic steel plate that does not hold the neodymium magnet (rare earth magnet) that acts on the centrifugal force has a margin in the anti-centrifugal strength, so that the magnetic pole head core is enlarged and the neodymium magnet is embedded deeply while supporting high rotational speed. A magnetic flux short-circuit prevention hole for breaking a magnetic short-circuit in part is formed long in the radial direction, so that the magnetic flux due to the reverse polarity magnetic field due to the armature current in the direction opposite to the magnetization magnetization of the neodymium magnet is independent of the frequency. It leaks without heat loss and suppresses reverse polarity magnetic field and temperature rise in neodymium magnets.

By using a rotor core with a hybrid configuration of a magnetic steel plate and a non-ferromagnetic metal plate, it becomes easy to reduce the gap between the magnetic steel plate and the magnetic pole surface of the neodymium magnet in the magnet embedding hole drilled by punching. , Keep the permeance coefficient large and make the neodymium magnet less susceptible to irreversible demagnetization.

High frequency of reverse polarity magnetic field due to armature current by placing bent metal plate between uneven surface inside magnetic pole head core from which non-ferromagnetic metal plate protrudes and outward magnetic pole surface of neodymium magnet The components are attenuated, and Joule heat generated in the metal plate as eddy current loss is thermally transferred asymmetrically to the core side of the magnetic pole head to suppress the temperature increase of the reverse polarity magnetic field applied to the neodymium magnet and the neodymium magnet.

A relatively large through hole is drilled in the magnetic pole head core that can be increased with a margin of anti-centrifugal strength, and the temperature of the neodymium magnet rises by circulating air through the heat exchange part inside the rotor through the through hole. Suppress. By combining this configuration with a plurality of the above means, an embedded magnet synchronous motor equipped with a neodymium magnet having a low dysprosium content is used in a high temperature environment such as a hybrid vehicle.

The increase in the magnetic flux leakage of the neodymium magnet at the magnetic flux short-circuit prevention hole is compensated by maintaining the residual magnetic flux density Br large by reducing the dysprosium content and suppressing the temperature rise, thereby maintaining the magnet torque large.

High efficiency by reducing the iron loss and q-axis inductance at the magnetic pole head core that can increase the cross-sectional area, and reducing the heat loss in the vicinity of the reverse polarity magnetic field neodymium magnet that becomes smaller due to leakage at the magnetic flux short-circuit prevention hole. To expand the driving range.

The rotor of the embedded magnet synchronous motor according to the present invention has an annular shape in a rotor core in which magnetic steel plates and non-ferromagnetic metal plates are alternately stacked as described in claim 1 in order to increase the centrifugal strength. The rare earth magnet on which the centrifugal force acts is held only by a non-ferromagnetic metal plate having a wide outer peripheral portion and a high tensile strength. The first magnet embedding hole of the magnetic steel plate and the second magnet embedding hole of the non-ferromagnetic metal plate are drilled at the overlapping positions of the magnetic poles of the rotor, and the second magnet embedding hole is the second in the second magnet embedding hole. The outer peripheral side end portion of the first protrusion is protruded in the central direction where the rotation axis is located from the first outer peripheral side end portion of the first magnet embedding hole. Only the second outer peripheral side end portion of the non-ferromagnetic metal plate is made to contact the outward magnetic pole surface of the rare earth magnet.

In order to reduce the reverse polarity magnetic field applied to the neodymium magnet by branching and leaking the magnetic flux accompanying the reverse polarity magnetic field due to the armature current without any heat loss regardless of the frequency, further, in claim 1, the centrifugal strength strength is sufficient. A magnetic flux short-circuit prevention hole extended in the radial direction is formed from the vicinity of the circumferential end of the first magnet embedding hole of the magnetic steel plate.

In order to use a resource-rich light rare earth element neodymium (Nd) as a magnet with a large energy product, in claim 2, a neodymium magnet is used as the rare earth magnet.

Since the magnetic steel plate is released from the role of positioning and holding the neodymium magnet, the positioning and holding of the neodymium magnet is performed only by the non-ferromagnetic metal plate, and the gap between the magnetic pole surface of the neodymium magnet and the magnetic steel plate is reduced. In order to keep the permeance coefficient large, the second outer peripheral end of the second magnet embedding hole of the non-ferromagnetic metal plate and the second outer peripheral end as shown in FIG. The outer end magnetic pole surface and the side portion of the neodymium magnet whose corners are chamfered are stopped at the side end portion that is continuous through the arc-shaped corner portion and the side end portion of the second radial bridge portion. A large gap is not made between the magnetic steel plate in which the first magnet embedding hole is drilled and the magnetic pole surface of the neodymium magnet, and the magnets are close to each other in parallel.

A metal plate placed between the magnetic pole head core and the outer magnetic pole face of the neodymium magnet to attenuate the high frequency component of the reverse polarity magnetic field due to the armature current by heat loss and conduct heat to the magnetic pole head core. According to claim 4, the metal is aligned with the laminated surface in which the first outer peripheral end of the magnetic steel plate is continuous and the uneven laminated surface inside the magnetic pole head core made of the protruding non-ferromagnetic metal plate. The outer peripheral magnetic pole of the neodymium magnet and the second outer peripheral side end of the non-ferromagnetic metal plate in which the plate is bent and formed into a shape having a crest and a trough, and the crest is on the magnetic pole head core side. It is made to hit the surface side.

In order to cause Joule heat generated by the metal plate to be increased on the magnetic pole head core side and to reduce asymmetric heat transfer on the neodymium magnet side by attenuating the reverse polarity magnetic field caused by the armature current, The portion is flattened with a large area, and the valley portion is made to hit the outward magnetic pole surface of the neodymium magnet with a small area on the magnetic pole head core side.

In order to always contact the magnetic plate head core side, which is the laminated surface of the first outer peripheral side end portion of the magnetic steel plate, the metal plate is formed at a plurality of locations of the metal plate as in claim 6. The cantilevered elastic part is larger than the difference between the height of the trough and the crest of the metal plate, and is projected from the flat surface of the crest to the trough, and the crest is poled by the elastic force of the cantilevered elastic part. It is applied to the core side.

In order to increase the attenuation of the reverse polarity magnetic field due to the armature current and maintain a large permeance coefficient, the soft magnetism having a high permeability between the magnetic pole head core and the outer magnetic pole face of the neodymium magnet as in claim 7 The metal plate is arranged.

Even if the overall thickness of the metal plate is increased to greatly attenuate the reverse polarity magnetic field caused by the armature current, the shape can be flexibly deformed following the variation in the distance between the magnetic pole head core and the neodymium magnet. As in claim 8, a plurality of bent metal plates are arranged in a stacked manner.

Since the bent metal plate is stabilized by being positioned by a common magnet-embedding hole penetrating the first magnet-embedding hole and the second magnet-embedding hole alternately, As in Item 9, the non-ferromagnetic metal plate is disposed so that the valley portion overlaps at a position facing the protruding second outer peripheral side end portion, and an outwardly extending slit is formed at the outer edge portion.

In order to be able to always hold the neodymium magnet on which the centrifugal force acts only with the non-ferromagnetic metal plate, the second non-ferromagnetic metal plate with respect to the first outer peripheral side end of the magnetic steel plate as in claim 10. The amount of protrusion in the center direction of the outer edge is the difference in linear expansion with respect to the length from the center of the rotating shaft to the outer edge of each axis due to the temperature difference between the room temperature and the maximum operating temperature. It is made more than the value which added.

The magnetic flux short-circuit prevention hole for branching and leaking the magnetic flux accompanying the reverse polarity magnetic field due to the armature current before applying to the neodymium magnet is continuously connected to the outer periphery from the circumferential end of the first magnet embedding hole. It is drilled by extending in the radial direction to the bridge portion. In the twelfth aspect, the first magnet embedding hole is continuous from the first outer peripheral side end portion, and extends from the bridge portion in the vicinity of the first magnet embedding hole in the circumferential direction to the outer periphery in the radial direction. Drilled.

Based on the results of conventional embedded magnet synchronous motors, the amount of magnetic flux entering the neodymium magnet is made appropriate by leaking the magnetic flux associated with the reverse polarity magnetic field in the magnetic flux short-circuit prevention hole without considering the attenuation due to the metal plate. In order to lead to the possibility of using a neodymium magnet having a dysprosium content lower than 5 wt% in a high temperature environment, the amount of magnetic flux accompanying the reverse polarity magnetic field due to the armature current applied to the neodymium magnet is The magnetic head is configured to be smaller than two thirds of the magnetic flux entering from the entrance of the magnetic pole head core.

In order to form a rotor core that is laminated with a gap between a magnetic steel plate having a large lamination thickness ratio and a non-ferromagnetic metal plate having a small lamination thickness ratio, the magnetic steel sheets are integrated by an uneven fitting portion. An escape hole that does not hit the fitting portion is formed at a position facing the non-ferromagnetic metal plate.

In order to strengthen positioning and torque transmission of the laminated rotor cores and enable post-insertion of the neodymium magnets to hold down the end faces of the neodymium magnets, the protrusions protrude from the inner periphery of the rotor cores. The key is fitted into a key groove provided at a corresponding position on the outer peripheral portion of the rotor hub integrated with the rotary shaft, and the end surface is pressed by an end plate having a plurality of protruding portions outward in the diameter, An annular ring is fitted and fixed in the stacking direction.

In order to facilitate the process of incorporating a neodymium magnet later, in claim 17, the first magnet embedding hole and the second magnet embedding hole disposed so as to overlap each other at equal angular intervals in the circumferential direction, A state of facing the end plate and a state of not facing the end plate can be selected by rotating the end plate at a predetermined angle.

In order to alleviate the pressure applied in the laminating direction at the rotor core and reduce the residual stress at the time of thermal expansion of the magnetic steel plate and the non-ferromagnetic metal plate to reduce the deterioration of magnetic properties, A state in which the fitting portion protruding from the end surface of the core and the end plate are in contact with each other by rotation of the end plate at a predetermined angle can be selected.

In order to allow the neodymium magnet to be cooled by an air flow, a through-hole around the neodymium magnet in which an air intake portion having an opening in the main rotation direction of the rotor is embedded in the magnetic pole head core as in claim 19 It is fixed to the end face of the rotor according to the position of.

In order to efficiently cool the neodymium magnet embedded in the rotor in a case closed from the outside air for waterproofing, dustproofing, and soundproofing, the air flowing into the through-hole in the air intake portion as in claim 20 It is circulated through the inside of the rotor core through the heat exchange part.

In order to promote the efficiency of heat exchange in the heat exchange section of air and the flow in the radial direction, in claim 21, heat having a plurality of fins composed of a part of a spiral shape with the center of the rotation axis as the center of rotational symmetry An exchange part is arranged to face the end face of the rotor.

In order to avoid irreversible demagnetization due to induced current mainly in power generation applications, as in claim 22, between the terminals of the armature winding in a cycle shorter than a half cycle defined by the reciprocal of (number of magnetic poles × rotational speed) Is electrically interrupted.

In order to effectively attenuate the reverse polarity magnetic field while reducing the switching loss, according to claim 23, when the temperature at a predetermined position of the embedded magnet synchronous motor is high, the electrical connection between the terminals of the armature winding The average period of is shortened.

In the configuration of the present invention, a terbium (Tb) -added neodymium magnet may be used as the embedded neodymium magnet having a large energy product.

In the configuration of the present invention, a samarium / cobalt magnet may be used instead of the neodymium magnet.

A rotor core laminated in a hybrid configuration with a magnetic steel plate with a high lamination thickness ratio and a non-ferromagnetic metal plate with a low lamination thickness ratio has a centrifugal force that is wide only from the outer periphery and has a high tensile strength. By holding the acting neodymium magnet, it has a high strength against centrifugal force.

Since the magnetic steel sheet is released from holding a neodymium magnet to which centrifugal force acts, a magnetic pole head core having a sufficient anti-centrifugal strength and having a large cross-sectional area can be used. Longer in the radial direction from the vicinity of the circumferential end of the neodymium magnet in order to break a magnetic short circuit in a part of the magnetic steel sheet that embeds the neodymium magnet deeply and at the same time leaks a part of the magnetic flux accompanying the reverse polarity magnetic field due to the armature current. A magnetic flux short-circuit prevention hole can be formed.

Since the magnetic steel plate is released from the positioning of the neodymium magnet, punching becomes easy without providing a large gap between the magnetic pole surface of the neodymium magnet and the magnetic steel plate, and the permeance coefficient can be maintained large, so the irreversible reduction is achieved. Easy to avoid magnetism. In addition, a large magnetic flux density Bd at the operating point in the BH demagnetization curve can be secured.

A magnetic flux short-circuit prevention hole that can be drilled long in the radial direction. The magnetic flux associated with the reverse polarity magnetic field due to the armature current branches and leaks without heat loss regardless of the frequency, so that the reverse polarity magnetic field applied to the neodymium magnet and the neodymium magnet Temperature rise due to Joule heat can be suppressed.

A metal plate that is bent to match the uneven surface inside the core of the magnetic pole head from which the non-ferromagnetic metal plate protrudes is placed on the magnetic pole surface of the neodymium magnet. Before the component enters the neodymium magnet, it is attenuated by heat loss, and a large amount of Joule heat is generated in the magnetic pole head core that is generated by the metal plate that performs asymmetrical heat conduction with the area on the side facing the magnetic pole head core increased. Thus, the reverse polarity magnetic field applied to the neodymium magnet and the temperature rise of the neodymium magnet can be suppressed.

The neodymium magnet can be cooled by circulating air through the heat exchange section inside the rotor and the relatively large through-hole formed in the magnetic pole head core that can be increased from the margin of centrifugal strength. By combining with the plurality of means, a neodymium magnet having a low dysprosium content can be used for an embedded magnet synchronous motor such as a hybrid vehicle.

By supplementing the increase in leakage of the magnetic flux of the neodymium magnet through the magnetic flux short-circuit prevention hole with the residual magnetic flux density Br that can be kept large by reducing the dysprosium content and increasing the temperature of the neodymium magnet, the magnet torque can be kept large.

High-efficiency operation with low iron loss and q-axis inductance reduction in the magnetic pole head core that can increase the cross-sectional area, and loss reduction in the neodymium magnet and nearby due to magnetic flux without heat loss in the magnetic flux short-circuit prevention hole Can widen the area.

By increasing the lamination thickness ratio of the non-ferromagnetic metal steel plate in the rotor core of the hybrid configuration, the centrifugal strength can be further improved and the maximum rotation speed of the rotor can be increased.

Example 1 of the rotor of the interior permanent magnet synchronous motor of the present invention is shown by a partially enlarged end face. Example 1 is shown with the whole figure including an armature. The shape of the magnetic steel plate of Example 1 and a nonferromagnetic metal plate is shown. The exploded block diagram of the rotor core of Example 1 is shown. It is a figure explaining the magnetic flux path | route of Example 1. FIG. The cross section which added the metal plate to Example 1 is expanded and shown. The cross section which added the different metal plate to Example 1 is expanded and shown. The cross section which added the metal plate piled up on Example 1 is expanded and shown. The structure of the end surface of Example 1 is shown. A part of cooling structure of Example 1 is shown. The cross section of the cooling structure of Example 1 is shown. The other part of the cooling structure of Example 1 is shown. Example 2 of the present invention is shown by a partially enlarged end face in the stacking direction. The exploded block diagram of the rotor core of Example 2 is shown. Example 3 of the present invention is shown by a partially enlarged end face in the stacking direction. The rotor of the conventional interior magnet synchronous motor is shown. The characteristic of the conventional neodymium magnet is shown.

The rotor of the interior permanent magnet synchronous motor of the present invention is configured to increase the anti-centrifugal strength and means for suppressing the reverse polarity magnetic field and temperature rise in the neodymium magnet based on the fact that the anti-centrifugal strength can be increased. The embodiment will be described on the assumption of the items (0063) to (0080).

The use of an embedded magnet synchronous motor such as a hybrid vehicle requires heat resistance as well as anti-centrifugal strength and a wide high-efficiency region, and is required to cope with the configuration of a rotor in which a permanent magnet is embedded.

The magnetic characteristics of the magnet are indicated by a magnetization curve (hysteresis loop), and the magnetic flux density B is represented by the sum of the applied magnetic field H and the magnetic polarization J of the magnet.
B = μH + J
B: Magnetic flux density (T, Tesla), H: Magnetic field (A / m), J: Magnetic polarization (T),
μ: The demagnetization curve shown in the second quadrant of the vacuum permeability magnetization curve is a JH demagnetization curve indicating the magnitude of the magnetic polarization J that varies with the magnetic field H, and the magnetic polarization of the magnet in the magnetic field H. There is a BH demagnetization curve showing the total magnetic flux density B plus J.

The magnetic polarization J at the magnetic field H = 0 in the JH demagnetization curve is the residual magnetic polarization Jr, and the magnetic field value at which the magnetic polarization J = 0 is the coercive force Hcj. Further, the magnetic flux density B at the magnetic field H = 0 in the BH demagnetization curve becomes the residual magnetic flux density Br. In the second quadrant, the magnetic flux density at the operating point that is the intersection of the operating line with the permeance coefficient having a negative slope and the BH demagnetization curve is indicated by Bd. The greater the coercive force Hcj, the more heat resistant, and the higher the temperature, the lower the coercive force Hcj and the residual magnetic flux density Br (or residual magnetic polarization Jr). In order to increase the magnetic flux density Bd and make it difficult to cause irreversible demagnetization even when the temperature rises, it is necessary to increase the permeance coefficient.

The embedded magnet synchronous motor is PWM (Pulse Width Modulation) driven by an inverter. A sinusoidal current drive with a relatively high carrier frequency relative to the reciprocal of the electrical angular period and a large degree of freedom in current vector control is generally used. The magnetic field generated by the armature current applied to the neodymium magnet includes frequency components other than the carrier frequency due to the influence of the inductance and resistance of the armature winding, but has a PWM carrier frequency whose main component is around 1 kHz as a fundamental wave. Yes.

Neodymium magnets with a large energy product are advantageous for downsizing embedded magnet synchronous motors, and heat resistance needs to be improved for use in hybrid vehicles and the like, and heavy rare earths are required to have a high coercive force Hcj. The elemental dysprosium is added. However, in order to reduce the dysprosium content because of the high price and availability of dysprosium and the decrease in residual magnetic flux density Br, the reverse polarity magnetic field in the opposite direction to the magnetization magnetization applied to the neodymium magnet is reduced, and the neodymium magnet It is necessary to suppress the temperature rise at

In the direction in which the magnetic resistance is the largest, the direction of the winding flux linkage generated by the permanent magnet is the d axis, and the direction between the magnetic poles having the minimum magnetic resistance and orthogonal to the electrical angle is the q axis, The three-phase windings that are stationary on the stator are equivalent to two d and q windings that rotate in synchronization with the rotor in which the permanent magnets are embedded and are stationary, Current vector control is facilitated by being regarded as two electrically independent DC circuits having inductance.

An embedded-magnet synchronous motor is a magnet torque generated by energy conversion due to a change in the armature flux linkage caused by the permanent magnet and armature current, and a change in the inductance of the armature winding due to the rotational position due to the magnetic saliency. The reluctance torque generated by converting the magnetic energy stored in the air gap into mechanical energy can be controlled by vector control with the armature current, so that the torque and efficiency can be selected.

Torque is obtained from the outer product of the current vector and the armature flux linkage vector. The equation representing the torque T is expressed by the following equation, where the magnet torque generated by the permanent magnet is the first term and the reluctance torque generated by the difference in inductance is the second term.
T = Pn · ψa · iq + Pn · (Ld−Lq) id · iq
= Pn {ψa · Ia · cos β + 1/2 · (Lq−Ld) Ia · Ia · sin 2β}
Pn: number of counter poles ψa: effective value id of armature flux linkage by permanent magnet, iq: d of armature current, q-axis component Ld: self-inductance (d-axis inductance) of d-axis armature winding
Lq: q-axis armature winding self-inductance (q-axis inductance)
Ia: Armature current amplitude (current vector magnitude)
β: Armature current advance angle from q-axis (current phase)

The efficiency of the machine-mechanical conversion of the embedded magnet synchronous motor (motor) needs to be ensured to be high by current vector control corresponding to the load and the rotational speed. In order to expand the constant output range up to a high rotation speed while suppressing the induced voltage by the magnetic flux weakening control and to operate with high efficiency, it relies heavily on the reluctance torque. In addition, reluctance torque is used to obtain a large torque even at a low rotational speed as in the constant torque region of the maximum torque control. As a result, by passing a d-axis current (d-axis component of the armature current) that depends on the current phase β of the armature current, a negative d-axis electron reaction magnetic flux −Ld · id demagnetizes neodymium magnets. The magnetic flux accompanying the reverse polarity magnetic field due to the armature current applied to the neodymium magnet, or the response to reducing the reverse polarity magnetic field mainly determines the range of the dysprosium content rate that does not cause irreversible demagnetization.

The copper loss due to the current flowing through the armature winding increases in the overall loss ratio when operating at a high load. At low loads, the ratio of iron loss, mainly eddy current loss, is large. In the stator, iron loss is often generated in the stator teeth, and in the rotor, the iron loss is frequently generated in a portion having a small cross-sectional area in the q-axis magnetic path (q-axis magnetic flux path) of the rotor core. In a neodymium magnet having a small specific resistance, eddy current loss occurs in a reverse polarity magnetic field having a high frequency component due to the d-axis component (d-axis current) of the armature current.

In order to increase the reluctance torque, the advance angle (current phase) β of the armature current from the q-axis is increased, but the current phase β at which the efficiency is maximized is the minimum armature current and the minimum copper loss. And the current phase at which the total armature flux linkage is minimized and the iron loss is minimized. As a result, the d-axis component id of the amplitude Ia (the magnitude of the current vector) of the armature current in the current phase direction correspondingly increases and is equivalent to the magnetic flux accompanying the reverse polarity magnetic field caused by the armature current. The child reaction magnetic flux -Ld · id also increases correspondingly.

A reverse polarity magnetic field in the direction opposite to the magnetization magnetization of the neodymium magnet includes a reverse polarity magnetic field caused by an induced current generated in the armature winding. Since the induced voltage associated with the induced current increases as the rotational speed increases, it is possible to cope with a high rotational speed by a weak magnetic flux control that suppresses the induced voltage by increasing -Ld · id so as not to exceed a certain voltage.

Neodymium magnets may be subjected to other reverse polarity magnetic fields. The induced voltage generated when the inverter is shut down due to the operation of the protective function of the driving inverter, the spike voltage when the switching element is turned off, etc., which have many high frequency components and the conventional embedded magnet shown in FIG. In the embodiment of the present invention in which the neodymium magnet is embedded deeper in the magnetic pole head core, it is treated that the irreversible demagnetization of the neodymium magnet does not occur. The description of the reverse polarity magnetic field means the reverse polarity magnetic field due to the d-axis component (d-axis current) of the armature current and the reverse polarity magnetic flux due to the induced current during rotation, and is described collectively as the reverse polarity magnetic field due to the armature current. The In general, the main frequency component of the reverse polarity magnetic field caused by the induced current is 500 Hz or less and low.

When the anti-centrifugal strength of the rotor is ensured, even at a high rotational speed, there is a margin for selecting the size and shape of the magnetic pole head core disposed in the d-axis direction from the outer magnetic pole surface of the neodymium magnet. The reverse polarity magnetic field applied to the neodymium magnet can be reduced by providing a magnetic flux short-circuit prevention hole that branches and leaks the reverse polarity magnetic field due to the current in a path other than the neodymium magnet without heat loss. In addition, since the cross-sectional area of the magnetic pole head core can be increased, the magnetic saturation can be relaxed and the reduction of the q-axis inductance Lq can be suppressed.

Neodymium magnets embedded deeply in the magnetic pole head core have a low specific resistance even when the permeability is the same as that of air, and the magnet thickness is increased to a few millimeters (millimeters). Even polar magnetic fields are converted to Joule heat until they are greatly attenuated as eddy currents, raising their temperature. In order not to raise the temperature of the neodymium magnet as much as possible, it is necessary to reduce the reverse polarity magnetic field centering on the high frequency component applied to the neodymium magnet.

As a method of reducing the reverse polarity magnetic field due to the armature current immediately before being applied to the neodymium magnet, there is a method of disposing a metal plate, particularly a soft magnetic metal plate, on the outer magnetic pole face of the neodymium magnet. A high frequency component of the reverse polarity magnetic field is attenuated by Joule heat loss due to the skin effect.

In the rotor core in which the silicon steel plate, which is a magnetic steel plate having a surface with insulation treatment, relatively low conductivity, and high magnetic permeability, is laminated, or in the magnetic pole head core that is a part thereof, the armature current Treated as low attenuation of reverse polarity magnetic field. If there is attenuation, the reverse polarity magnetic field caused by the armature current applied to the neodymium magnet can be further reduced, and there is a margin in the dysprosium content and the coercive force Hcj.

The stator tends to generate a large amount of heat due to copper loss in the armature winding or iron loss in the stator teeth, but it is easily cooled because it is fixed on the outside. The rotor is only supported by the rotating shaft, and heat is conducted between the rotor and the stator through the air that flows at a relatively high speed through the air gap. Therefore, it is not easy to make the temperature of the neodymium magnet lower than the temperature of the stator teeth.

Hereinafter, a rotor of a magnet-embedded synchronous motor according to the present invention will be described with reference to the drawings. 1 to 12 show a first embodiment of the present invention, FIGS. 13 and 14 show a second embodiment, FIG. 15 shows a third embodiment, FIG. 16 shows a rotor of a conventional magnet-embedded synchronous motor, and FIG. 17 is a diagram for explaining the characteristics of a conventional neodymium magnet. In the different figures, the same parts are in principle indicated by the same reference numerals.

FIG. 1 shows a part of the rotor according to the first embodiment of the present invention, which is enlarged together with the stator, as an end face in the axial direction (stacking direction). The rotor 11 is formed by alternately laminating a plurality of stacked magnetic steel plates 12 and a non-ferromagnetic metal plate 13 that is mostly hidden by the magnetic steel plates 12 and fitting the rotor 11 into the rotor hub 14. An air gap 17 is provided between the stator teeth 16 of the stator 15 and the rotor 11.

At positions corresponding to the magnetic poles of the magnetic steel plate 12 and the non-ferromagnetic metal plate 13, first magnet embedding holes 18 and 19 that are respectively drilled in a V shape, and a second magnet embedding hole 20, 21 is provided at the overlapping position, and neodymium magnets (NdFeB-based sintered magnets) 22 and 23 having a large energy product are embedded and arranged.

In order to break a magnetic short circuit in a part of the magnetic steel sheet 12 having a large outer periphery width, the magnetic flux short circuit prevention holes 24 and 25 have diameters continuously from the circumferential ends of the first magnet embedding holes 18 and 19. It extends in the direction to the bridge portions 26 and 27 at the outer peripheral portion. The magnetic pole head core 28 is in contact with the magnetic flux short-circuit prevention holes 24 and 25 at both ends in the circumferential direction, and is formed at an outer position facing the V-shaped arrangement of the neodymium magnets 22 and 23. Is held by the radial bridge portion 29. In order to obtain a high tensile strength, the non-ferromagnetic metal plate 13 is not provided with holes corresponding to the magnetic flux short-circuit prevention holes 24 and 25, and a wide annular portion is formed from the outer periphery, so that the neodymium magnet 22 is formed. , 23, the centrifugal strength strength during high-speed rotation is maintained.

Since the magnetic steel plate 12 does not need to hold the neodymium magnets 22 and 23 on which the centrifugal force acts, there is an arc-shaped outer periphery and the neodymium magnet 22 at the center of the magnetic pole head core 28 that is enlarged with a margin. , 23 through-holes 30 having an inverted triangular approximation substantially along the V-shaped outer magnetic pole face are formed in the magnetic steel plate 12 and the non-ferromagnetic metal plate 13 in common with a relatively large cross-sectional area. Air enters the through hole 30 from one end face of the rotor 11 and flows out from the other end face. Although the through hole 30 does not have to be an inverse triangle approximation, the cross-sectional area of the magnetic flux path of the q-axis magnetic flux in the magnetic pole head core 28 needs to be increased.

The second outer peripheral end portions 32 and 33 in the second magnet embedding holes 20 and 21 of the non-ferromagnetic metal plate 13 correspond to the first magnet embedding holes 18 and 19 in the magnetic steel plate 12. It protrudes from the outer peripheral side ends 34 and 35 toward the center where the rotation axis is located. The metal plates 36 and 37 are disposed between the outer magnetic pole surface of the neodymium magnets 22 and 23 and the magnetic pole head core 28, and are the magnetic pole head core 28 that is a laminated continuous surface of the first outer peripheral side end portions 34 and 35. Of the non-ferromagnetic metal plate 13 and the outer peripheral side end portions 32 and 33 of the protruding non-ferromagnetic metal plate 13 and the outer magnetic pole surfaces of the neodymium magnets 22 and 23 so as to be in contact with each other. Is done.

The second outer peripheral side end portions 32 and 33 in the second magnet embedding holes 20 and 21 of the non-ferromagnetic metal plate 13 are the first magnet embedding holes 18 and 19 in the magnetic steel plate 12. Although protruding so that it can be discriminated from the outer peripheral side end portions 34 and 35 in the central direction where the rotation axis is located, the protruding amount is set to about 0.3 mm at room temperature. Moreover, the metal plates 36 and 37 about 0.3 mm thick are shown by the thick cross section.

Soft magnetic spring plates 40 and 41 are disposed between the inner magnetic pole surfaces of the neodymium magnets 22 and 23 and the first inner peripheral side end portions 38 and 39 in the first magnet embedding holes 18 and 19. Soft magnetic spring plates 40 and 41 having a thickness of about 0.3 mm are shown in thicker sections.

The neodymium magnets 22 and 23 are positioned by the second magnet embedding holes 20 and 21 formed in the non-ferromagnetic metal plate 13. The second outer peripheral side end portions 32 and 33 in the second magnet embedding holes 20 and 21 in the non-ferromagnetic metal plate 13 and the second outer peripheral side end portions 32 and 33 through arc-shaped corners. In the circumferential side end portion and the side end portion of the second radial bridge portion 42 that are continuous with each other, the gap between the outer magnetic pole surface and the side portion of the neodymium magnets 22 and 23 whose corner portions are chamfered is reduced, Positioned. Compared to the rotor of the conventional embedded magnet synchronous motor of FIG. 16, a relatively large gap is not formed in a part between the magnetic pole surfaces of the neodymium magnets 22 and 23 and the magnetic steel sheet 12, so that the permeance coefficient is kept large. In addition, the neodymium magnets 22 and 23 can be used effectively. By maintaining a large permeance coefficient, the neodymium magnets 22 and 23 are hardly irreversibly demagnetized.

In the case of using a neodymium magnet whose corners are not chamfered, it is sufficient that the second magnet embedding hole of the non-ferromagnetic metal plate 13 has a shape that can be punched and can position the outer magnetic pole face and the end of the neodymium magnet. The magnetic steel plate is made not to hit anything other than the inward magnetic pole surface of the neodymium magnet, and is made parallel to the magnetic pole surface of the neodymium magnet so that there is no large gap.

Centrifugal force acting on the neodymium magnets 22 and 23 when the rotor 11 rotates is almost at the projecting second outer peripheral end portions 32 and 33 of the second magnet embedding holes 20 and 21 of the non-ferromagnetic metal plate 13. However, a part is hold | maintained at the side edge part in the 2nd magnet embedding holes 20 and 21, and it is not hold | maintained with the magnetic steel plate 12. FIG. The non-ferromagnetic metal plate 13 that receives the centrifugal force acting on the neodymium magnets 22 and 23 is formed with a wide annular portion from the outer periphery so as to have a large tensile strength, and is adjacent to the second magnet embedding hole. 20 and 43, and 21 and 44 through the wide radial support portions hidden under the inter-pole cores 52 and 53 of the laminated magnetic steel sheet 12, and similarly, Since it is connected from the inner periphery to a wide and annular portion hidden under the back core 54, it has a high strength against centrifugal force. Even when the strength safety factor is sufficient, the ratio of the lamination thickness of the non-ferromagnetic metal plate 13 to the magnetic steel plate 12 in the rotor core 31 can be reduced.

The magnetic flux short-circuit prevention holes 24 and 25 drilled only in the magnetic steel plate 12 are drilled for the purpose of preventing an increase in the cross-sectional area of magnetic short-circuiting of the magnetic steel plate 12 caused by burying the neodymium magnets 22 and 23 deeply. As a result, the magnetic flux accompanying the reverse polarity magnetic field due to the armature current in the direction opposite to the magnetization magnetization of the neodymium magnets 22 and 23 is branched and leaked before being applied to the neodymium magnets 22 and 23 through the magnetic flux short-circuit prevention holes 24 and 25. It will be. However, it is required not to leak much magnetic flux from the neodymium magnets 22 and 23.

The inward magnetic pole surfaces of the neodymium magnets 22 and 23 are laminated surfaces of the first inner peripheral side end portions 38 and 39 of the first magnet embedding holes 18 and 19 of the magnetic steel plate 12, and the soft magnetic spring plates 40 and 41. Between the two. A second inner peripheral side end portion indicated by a broken line of the second magnet embedding holes 20 and 21 of the non-ferromagnetic metal plate 13 is a rotational axis from the first inner peripheral side end portions 38 and 39 of the magnetic steel plate 12. It is formed so as to be depressed toward the center where it is located.

The neodymium magnets 22 and 23 are embedded deeply by the magnetic pole head core 28 and are largely separated from the tips of the plurality of stator teeth 16 of the stator 15. The local magnetic field generated in the vicinity of the tip of the stator tooth 16 due to the current of the armature winding (not shown) wound across the plurality of stator teeth 16 is reduced when applied to the neodymium magnets 22 and 23. The In the first embodiment, distributed winding is shown. However, in the concentrated winding configuration, a large local magnetic field is likely to occur near the tip between adjacent stator teeth, and irreversible demagnetization is achieved by deeply embedding the permanent magnet. It is known that is less likely to occur.

FIG. 2 shows the rotor of the interior permanent magnet synchronous motor of the present invention over the entire end face including the stator. In the rotor 11, the number of neodymium magnets corresponding to the number of four counter poles is embedded, and in each magnetic pole in which the neodymium magnets are arranged in a V shape, the adjacent neodymium magnets 22, 23, 45, and 46 are in the radial direction. Different poled properties. The rotor core 31 is fixed by a portion of the plurality of protruding keys 47 fitted in the key groove 48 and fitted into the rotor hub 14, and is rotatable by the rotation shaft 49.

The stator 15 is shown in a simplified form, and distributed armature windings are omitted. In one magnetic pole, most of the magnetic flux emitted from the outward magnetic pole surfaces of the V-shaped neodymium magnets 22 and 23 enters the plurality of stator teeth 16 across the air gap 17 from the magnetic pole head core 28, and the stator 15. , Passes through the plurality of stator teeth 50 and 51, crosses the air gap 17 again, enters the inter-magnetic pole cores 52 and 53, and returns from the back core 54 to the inward magnetic pole surfaces of the neodymium magnets 22 and 23. The flow of magnetic flux interlinking the plurality of stator teeth 16 contributes to the magnet torque as armature interlinkage magnetic flux.

Part of the magnetic flux that enters the magnetic pole head core 28 from the outer magnetic pole face of the neodymium magnets 22 and 23 is a magnetic flux that passes through the outer bridge portions 26 and 27 and the first radial bridge portion 29 to a magnetic saturation state. The punched portion forms a closed path inside the rotor core 31 as a magnetic flux that leaks across the magnetic flux short-circuit prevention holes 24 and 25 having a low magnetic permeability because of air. These magnetic fluxes do not contribute to torque.

FIG. 3 shows the shapes of magnetic steel plates and non-ferromagnetic metal plates stacked in a hybrid configuration. 3A shows the shape of the magnetic steel plate 12 having a large lamination thickness ratio, and FIG. 3B shows the shape of the non-ferromagnetic metal plate 13 having a small lamination thickness ratio. In the magnetic steel plate 12, corresponding to each magnetic pole, the first magnet embedding holes 18, 19 and the magnetic flux short-circuit prevention holes 24 continuous from the circumferential ends of the first magnet embedding holes 18, 19 are provided. 25 are extended in the radial direction. In the non-ferromagnetic metal plate 13, second magnet embedding holes 20, 21 are formed at positions overlapping the first magnet embedding holes 18, 19 of the magnetic steel plate 12.

The second outer peripheral side end portions 32 and 33 in the second magnet embedding holes 20 and 21 drilled in the non-ferromagnetic metal plate 13 are the first magnet embedding holes 18 drilled in the magnetic steel plate 12. , 19 is substantially parallel to the first outer peripheral side end portions 34, 35 and protrudes by about 0.3 mm in the central direction where the rotation axis is located. The neodymium magnet to which the centrifugal force acts during rotation is held only by the non-ferromagnetic metal plate 13 having the protruding second outer peripheral end portions 32 and 33.

The non-ferromagnetic metal plate 13 that receives the centrifugal force acting on the neodymium magnet and itself has a wide annular portion 55 having a large tensile strength from the outer periphery, and adjacent second magnet embedding holes 20, 43, and 21. Wide radial support portions 56 and 57 between 44 and a portion 58 having a large annular strength from the inner periphery and having a high tensile strength are integrated to have a centrifugal strength strength even if the ratio of the laminated thickness is small. Made up.

Side end portions 59, 60, 61, 62 of the second magnet embedding holes 20, 21 in the non-ferromagnetic metal plate 13 are arcuate corner portions 63, 64 from the second outer peripheral side ends 32, 33. And the neodymium magnet formed continuously through 65 and 66 and having chamfered corners is positioned with a small gap between each side portion. In the case of using a neodymium magnet whose corners are not chamfered, positioning portions corresponding to the second outer peripheral side end portions 32 and 33 and the side end portions 59 to 62 are formed. The part corresponding to 66 is formed into a shape in which a part of the second outer peripheral side end portions 32, 33 is recessed.

The inner peripheral portions of the magnetic steel plate 12 and the non-ferromagnetic metal plate 13 are formed into circles having substantially the same diameter, and a plurality of protruding keys 47 and 67 are formed at a plurality of the same positions to enable positioning and torque transmission. . The outer circumference does not necessarily have to be a circle with the same diameter. However, in order to give the non-ferromagnetic metal plate 13 a high tensile strength, the outer circumference of the magnetic steel plate 12 is slightly smaller than the outer diameter or the same diameter. Good.

For the magnetic steel sheet 12, a silicon steel sheet having a silicon (Si) content of about 3% is suitable in terms of the balance of high magnetic permeability, low electrical conductivity, small hysteresis, and punchability. There is no need to select a material whose content is increased and the mold consumption during punching is severe. Further, as the non-ferromagnetic metal plate 13, an austenitic stainless steel plate is an example of a material suitable for non-magnetism, low electrical conductivity, high tensile strength, ease of processing, and versatility.

When a silicon steel plate is used for the magnetic steel plate 12 and an austenitic stainless steel plate is used for the non-ferromagnetic metal plate 13, the respective linear expansion coefficients are 13 (× 10 minus 6 / K) and 17.3 (× 10 minus). As an example, at a length of 65 mm from the center, the austenitic stainless steel plate has a linear expansion difference of about 0.05 mm with a temperature difference of 200 degrees Celsius from the normal temperature and the maximum operating temperature. It grows greatly. When the positions are aligned at normal temperature, the second outer peripheral end portions 32 and 33 that should always be exposed and protruded are at a higher distance from the center than the positions of the first outer peripheral end portions 34 and 35 at a high temperature. Becomes larger and buried in the rotor core.

At normal temperature, the second outer peripheral end portions 32, 33 of the non-ferromagnetic metal plate 13 are at room temperature (20 degrees Celsius) and the maximum operating temperature from the position of the first outer peripheral end portions 34, 35 of the magnetic steel sheet 12. Projected in the center direction, larger than the difference in linear expansion of the length from the center of the rotating shaft caused by the temperature difference, and added to the projection amount by adding the machining tolerance and assembly tolerance to the projection amount In the temperature range, the second outer peripheral side end portions 32 and 33 of the non-ferromagnetic metal plate 13 can hold the neodymium magnet on which the centrifugal force acts.

When a silicon steel plate is used for the magnetic steel plate 12 and a nickel-chromium metal plate is used for the non-ferromagnetic metal plate 13, the linear expansion coefficients of the two are approximated. Centrifugal force is applied to the second outer peripheral end portions 32 and 33 that protrude from the position of the first outer peripheral end portions 34 and 35 toward the center, which is larger than the value obtained by adding the machining tolerance and the assembly tolerance. Holds neodymium magnet from centrifugal force during rotation.

FIG. 4 shows the configuration of the rotor core according to the first embodiment of the present invention. The ratio of the laminated thickness of the magnetic steel plates is set to be larger than the ratio of the laminated thickness of the non-ferromagnetic metal plates. It is necessary that magnetic saturation is difficult to occur in the rotor core due to the magnetic flux of a neodymium magnet embedded in the rotor core and the q-axis magnetic flux (q-axis armature reaction magnetic flux) due to the q-axis component of the armature current. . The ratio of the lamination thickness of the non-ferromagnetic metal plate that holds the neodymium magnet from centrifugal force is the shape and material strength of the non-ferromagnetic metal plate, the mass and embedding position of the neodymium magnet, the outer diameter of the rotor, the maximum rotation speed, and Determined by considering the safety factor.

FIG. 4A shows the rotor core 31 in a stacked state fitted to the rotor hub 14 and the members embedded in the rotor core 31. FIG. 4B shows a unit configuration of the magnetic steel plate 12 and the non-ferromagnetic metal plate 13 before being stacked in a hybrid configuration, including 21 0.3 mm-thick magnetic steel plates and a 0.3 mm-thick non-ferromagnetic metal. Shown in a state where three plates are stacked. The ratio of the laminated thickness of the magnetic steel plate and the non-ferromagnetic metal plate is set to about 7: 1. In the comparison of the laminated thickness, the thickness of the insulating treatment layer and the adhesive layer formed on the surface of the magnetic steel plate 12 is omitted.

The outer diameter of the rotor 11 is 150 mm, the maximum rotational speed is 14000 rpm, the cross section of each embedded neodymium magnet is 5.6 mm × 19 mm, and the embedding depth at the circumferential end of the V-shaped neodymium magnet is 9 When the width of the bridge portions 26 and 27 is 2.2 mm and the width of the first radial bridge portion 29 is 1.4 mm, The example of the ratio of lamination | stacking thickness with the non-ferromagnetic metal plate 13 using the plate of austenitic stainless steel is shown.

In FIG. 4B, the magnetic steel plate 12 is provided with concave and convex fitting portions 68 at a plurality of locations in the circumferential direction, and the plurality of plates are integrated by pressure bonding. The non-ferromagnetic metal plate 13 is provided with a relief hole 69 at a position facing the fitting portion 68 of the magnetic steel plate 12 during lamination. When the magnetic steel plate 12 and the non-ferromagnetic metal plate 13 having a unit configuration are overlapped, a gap is hardly formed between the surfaces.

The second outer peripheral side end portions 32 and 33 of the non-ferromagnetic metal plate 13 held in contact with the outer magnetic pole surface of the neodymium magnet are laminated with the first outer peripheral side end portions 34 and 35 of the magnetic steel plate 12. It is substantially parallel to the continuous surface and protrudes toward the center. Magnetic magnetic steel sheet 12 is provided with magnetic flux short-circuit prevention holes 24 and 25, but is not formed in non-ferromagnetic metal plate 13.

The magnetic pole head core 28 is formed by punching the magnetic steel plate 12 and is held by centrifugal force and magnetic force during rotation by the narrow bridge portions 26 and 27 and the central first radial bridge portion 29. These are integrated with the cores 52 and 53 between the magnetic poles via the bridge portions and the back core 54 which is wide and annularly continuous.

The non-ferromagnetic metal plate 13 has an anticentrifugal strength with a large tensile strength by having a wide annular configuration from the outer periphery and the inner periphery. In addition, since it is non-magnetic, it is possible to select a material centering on the tensile strength so that a small number of neodymium magnets to which centrifugal force acts during rotation can be held regardless of magnetic leakage.

When the laminated thickness of the non-ferromagnetic metal plate 13 becomes larger than the air gap of 0.5 mm to 0.6 mm formed between the stator (not shown) and the rotor core 31, the non-ferromagnetic metal A portion where the effective air gap is increased in a portion facing the plate 13 occurs. The tip of the stator tooth is relatively wide in the circumferential direction compared to the portion where the armature winding is wound, and magnetic saturation is less likely to occur except in the vicinity of the circumferential end of the tip portion. When the laminated thickness of the ferromagnetic metal plate 13 is about 0.9 mm, there is no problem that the air gap becomes large.

In the case of the rotor core 31 in which the non-ferromagnetic metal plates 13 are alternately laminated at a ratio of the lamination thickness of 7 to 1 with respect to the magnetic steel plate 12 having a large lamination thickness ratio, the rotor core averaged in the lamination direction. The saturation magnetic flux density of 31 is reduced by about 12%. Similarly, the magnetic pole head core 28 and the bridge portions 26 and 27, the first radial bridge portion 29, the inter-magnetic cores 52 and 53, and the back core 54 are similarly lowered.

Even if the magnetic pole head core 28 is laminated in a hybrid configuration including the non-ferromagnetic metal plate 13 and the saturation magnetic flux density is reduced by about 12%, the magnetic flux heads are prevented from being short-circuited by a large slope at both ends in the circumferential direction. By making the cross section deeper along the holes 24 and 25, magnetic saturation is less likely to occur due to magnetic flux caused by the armature current, particularly q-axis magnetic flux. In addition, since the widths of the magnetic flux short-circuit prevention holes 24 and 25 are relatively small, the magnetic flux from the stator is likely to enter without being obstructed from the outer peripheral portion of the rotor 11.

In the cores 52 and 53 between the magnetic poles, even if there is a decrease in the saturation magnetic flux density averaged in the stacking direction, the magnetic fluxes of the opposite magnetic poles cancel each other out because the opposite magnetic fluxes pass from each other. Saturation is unlikely to occur only with the q-axis magnetic flux due to the q-axis component (q-axis current). As a result, the reduction in q-axis inductance is alleviated and reluctance torque can be ensured up to a high rotational speed. Of course, iron loss is also reduced. By adopting the magnetic flux weakening control method on the premise that the magnet torque can be secured, a large output and a high efficiency characteristic can be obtained in a wide operation region.

In contrast, the magnetic pole head core 4 of the conventional example shown in FIG. 16 is laminated only with magnetic steel plates, and the saturation magnetic flux density averaged in the lamination direction is relatively large, but neodymium arranged in a V shape. Since the circumferential end of the magnet 2 is shallow and the cross-sectional area is small, the q-axis inductance is likely to decrease due to magnetic saturation caused by the q-axis magnetic flux. As a result, reluctance torque decreases and efficiency decreases.

By laminating the non-ferromagnetic metal plate 13, the saturation magnetic flux density at the bridge portions 26 and 27 of the magnetic steel plate 12 and the first radial bridge portion 29 is reduced by about 12% on the average in the lamination direction. This corresponds to the amount of magnetic flux leaking from the bridge portions 26 and 27 and the first radial bridge portion 29 being reduced by about 12%, which is desirable for effectively using the magnetic flux of the neodymium magnet. Accordingly, in order to increase the strength against the centrifugal force acting on the magnetic pole head core 28 itself of the magnetic steel plate 12, the widths of the bridge portions 26 and 27 and the first radial bridge portion 29 of the magnetic steel plate 12 are increased, or There is a margin for turning to reducing the number of neodymium magnets 22 and 23 embedded in the rotor core 31.

In FIG. 4A, the first magnet embedding holes 18 and 19 of the magnetic steel plate 12 and the second magnet embedding holes 20 and 21 of the non-ferromagnetic metal plate 13 shown in FIG. The neodymium magnets 22 and 23 embedded in the through-holes for magnet embedding that are formed by lamination are divided into two parts, respectively, and have a length close to the thickness of the rotor core 31 in the lamination direction. Between the outward magnetic pole surface of the neodymium magnets 22 and 23 to be inserted and the magnetic pole head core 28, bent metal plates 36 and 37 are arranged. Soft magnetic spring plates 40 and 41 are disposed between the inner magnetic pole surfaces of the neodymium magnets 22 and 23 and the rotor core 31. The soft magnetic spring plates 40 and 41 have stepped outer edges and a step, are made elastically deformable, and come into contact with the inner magnetic pole surfaces of the neodymium magnets 22 and 23 and the rotor core 31.

FIG. 5 shows the path of the magnetic flux from the neodymium magnet according to the first embodiment of the present invention, or the path of the magnetic flux due to the d-axis component (d-axis current) of the armature current equivalent to the magnetic flux due to the reverse polarity magnetic field due to the armature current. It is for explaining. The magnetic flux that emerges from the outer magnetic pole surfaces of the neodymium magnets 22 and 23 straddles the air gap 17 from the magnetic pole head core 28, and links the plurality of stator teeth 16 facing the magnetic pole head core 28. , The stator teeth 50 and 51 facing the cores 52 and 53 between the magnetic poles are interlinked, and the air gap 17 is straddled again to enter the cores 52 and 53 between the magnetic poles, and from the back core 54 to the neodymium magnets 22 and 23. A first magnetic flux path to the inward magnetic pole surface,

A second magnetic flux path that leaks from the magnetic pole head core 28 through the magnetic flux short-circuit prevention holes 24 and 25, enters the inter-magnetic cores 52 and 53, and extends from the back core 54 to the inward magnetic pole surfaces of the neodymium magnets 22 and 23; The third magnetic flux flows from the magnetic pole head core 28 through the bridge portions 26 and 27 and the first radial bridge portion 29 to the magnetic saturation state and reaches from the back core 54 to the inner magnetic pole surfaces of the neodymium magnets 22 and 23. The path is mainly branched into three magnetic flux paths.

The magnetic flux in the first magnetic flux path interlinking the plurality of stator teeth 16 becomes an armature interlinkage magnetic flux and contributes to torque. The second magnetic flux path and the third magnetic flux path that are closed in the rotor core 12 are paths that do not contribute to torque. For the neodymium magnets 22 and 23, the magnetic flux short-circuit prevention holes 24 and 25 are regarded as equivalent to the expansion of the air gap area, and the clearance between the magnetic pole surface of the neodymium magnets 22 and 23 and the first magnet embedding holes 18 and 19 is expanded. Compensates for the decrease in permeance coefficient, which decreases with. Unless the amount of useless reduction due to the magnetic fluxes of the neodymium magnets 22 and 23 is compensated, the magnet torque decreases.

The magnetic flux due to the d-axis component (d-axis current) of the armature current is a magnetic flux with a reverse polarity magnetic field that is directed to demagnetize the magnetization magnetization of the neodymium magnets 22 and 23. The magnetic flux accompanying the reverse polarity magnetic field by the armature current enters the magnetic pole head core 28 across the air gap 17 from the plurality of stator teeth 16, the magnetic flux leaking from the magnetic flux short-circuit prevention holes 24, 25, the neodymium magnet 22, Branching to the magnetic flux entering 23. In addition, although it is the magnetic flux attenuate | damped, so that it goes into the magnetic pole head core 28 deeply, and the magnetic flux which leaks out of the rotor core 31, it treats that these two types of magnetic flux do not have attenuation | damping and leakage. Even if the influence is taken into consideration later, the dysprosium content of the neodymium magnet may be lowered, but the conclusion should not be raised.

Since the bridge portions 26 and 27 and the first radial bridge portion 29 are preliminarily magnetically saturated with the magnetic flux from the neodymium magnets 22 and 23, the magnetization magnetization of the neodymium magnets 22 and 23 is demagnetized. The magnetic flux due to the reverse polarity magnetic field due to the armature current, which is the magnetic flux in the direction of the magnetic field, has the same polarity as the magnetization direction of the magnetic saturation in the bridge portions 26 and 27 and the first radial bridge portion 29. There is no room for saturation and almost no passage.

Since the magnetic pole head core 28 has a high magnetic permeability, a relatively low electrical conductivity, and thin silicon steel plates are insulated and laminated, the reverse magnetic field attenuation by the armature current is small. Of the magnetic pole head core 28, the circumferential end of the magnetic pole head core 28 excluding the vicinity of the bridge portions 26, 27 and the first radial bridge portion 29, and the first magnet embedding hole 18. , 19 are assumed to be approximately equal in magnetic potential at the first outer peripheral end portions 34, 35.

Since the permeability of the neodymium magnet is almost the same as that of air, it is accompanied by a reverse polarity magnetic field caused by an armature current that enters the magnetic pole head core 28 from the plurality of stator teeth 16 according to the ratio of the magnetic resistance based only on the configuration dimensions. The magnetic flux is branched into one magnetic flux path that leaks through the magnetic flux short-circuit prevention holes 24 and 25 and enters the cores 52 and 53 between the magnetic poles, and two magnetic flux paths that enter the neodymium magnets 22 and 23 and reach the back core 54.

The intention is that the conventional embedded magnet synchronous motor of FIG. 16 used in a hybrid vehicle has a neodymium magnet having a coercive force Hcj of about 2.4 MA / m (30 kOe) and a dysprosium content of 8 wt% to 10 wt%. Based on the results used, the thickness of the neodymium magnet, the diameter of the rotor, and the magnet opening angle (the angle formed by the center of the rotating shaft is the distance between the outermost peripheral portions of the magnetic flux short-circuit prevention hole) are almost the same. To do. In order to reduce the reverse polarity magnetic field due to the armature current applied to the neodymium magnets 22 and 23, assuming that there is no attenuation at the metal plates 36 and 37, the magnetic flux accompanying the reverse polarity magnetic field is reduced to the magnetic flux short-circuit prevention hole 24, regardless of the frequency. This is to lead to the possibility of using a neodymium magnet having a coercive force smaller than 1.6 MA / m (20 kOe) or having a dysprosium content lower than 5 wt%.

After the magnetic flux due to the reverse polarity magnetic field due to the armature current enters the magnetic pole head core 28 from the plurality of stator teeth 16, it leaks through the magnetic flux short-circuit prevention holes 24, 25 and enters the inter-magnetic cores 52, 53, and again the magnetic pole In the magnetic flux path entering the stator 15 from the plurality of stator teeth 50, 51 facing the intermediate cores 52, 53, the more the magnetic flux leaks from the magnetic flux short-circuit prevention holes 24, 25, the more the metal plates 36, 37 and the neodymium magnets 22, 23 The amount and density of the magnetic flux accompanying the reverse polarity magnetic field entering the magnetic field are reduced. As a result, the possibility of irreversibly demagnetizing the neodymium magnets 22 and 23 is reduced.

The amount of magnetic flux leaking across the magnetic flux short-circuit prevention holes 24 and 25 after the magnetic flux accompanying the reverse polarity magnetic field due to the armature current enters the magnetic pole head core 28 from the plurality of armature teeth 16, and the metal plates 36 and 37. The ratio of the amount of magnetic flux entering the neodymium magnets 22 and 23 across the magnetic field is determined by the relationship between the length of the center in the radial direction of the magnetic flux short-circuit prevention holes 24 and 25 and the average width in the orthogonal direction. And the (total) width of the outer magnetic pole faces of the neodymium magnets 22 and 23 and the interval between the first magnet embedding holes 18 and 19 which are the intervals between the magnetic steel plates 12 sandwiching the neodymium magnets 22 and 23, and soft magnetic It is determined by the ratio of magnetoresistance in the two magnetic circuits determined by the difference between the thickness of the metal plate and the total thickness of the soft magnetic spring plates 40 and 41. The ratio of the amount of magnetic flux leaking from the magnetic flux short-circuit prevention holes 24 and 25 and the amount of magnetic flux entering the metal plates 36 and 37 and the neodymium magnets 22 and 23 is determined in inverse proportion to the magnetic resistance ratio.

The length L from the bridge portions 26 and 27 at the radial center of the magnetic flux short-circuit prevention holes 24 and 25 to the position where the approximate interval ends, the average interval D in the orthogonal direction, and the outer magnetic pole surfaces of the neodymium magnets 22 and 23, respectively. The total width W, the distance between the first magnet embedding holes 18 and 19 in the magnetic steel plate 12, and the difference T between the total thickness of the soft magnetic metal plates 36 and 37 and the soft magnetic spring plates 40 and 41. It is set as the space | interval S (area multiplied by the unit length of the lamination direction) of the two positions 70 and 71 of the outermost periphery part of the magnetic flux short circuit prevention holes 24 and 25. FIG. Let Φ be the amount of magnetic flux associated with the reverse polarity magnetic field caused by the armature current entering from the entrance of the gap S between the magnetic pole head cores.

The ratio of the parallel magnetic resistance straddling the magnetic flux short-circuit prevention holes 24 and 25 and the magnetic resistance straddling the neodymium magnets 22 and 23 is (D / 2L) :( T / W). The ratio of the amount of magnetic flux straddling the magnetic flux short-circuit prevention holes 24 and 25 and the amount of magnetic flux entering the neodymium magnets 22 and 23 across the metal plates 36 and 37 out of the amount of magnetic flux accompanying the reverse polarity magnetic field due to the armature current entering from the entrance is:
(T / W): (D / 2L)
As a result, of the magnetic flux amount Φ associated with the reverse polarity magnetic field due to the armature current entering from the interval S that is the entrance of the magnetic pole head core 28,
A magnetic flux amount of Φ × {(D / 2L) / (D / 2L + T / W)} enters the metal plates 36 and 37 and the neodymium magnets 22 and 23.

In order to make the amount of magnetic flux entering the neodymium magnets 22 and 23 smaller than two thirds of the magnetic flux amount at the entrance of the magnetic pole head core 28, assuming that there is no attenuation at the metal plates 36 and 37,
Φ × {(D / 2L) / (D / 2L + T / W)} <(2/3) × Φ
By satisfying the above, from the results of the conventional embedded magnet synchronous motor of FIG. 16 using a neodymium magnet having a dysprosium content of 8 wt% to 10 wt%, the coercive force is less than two thirds of 2.4 MA / m (30 Oe). Alternatively, a neodymium magnet having a dysprosium content lower than 5 wt% is led to the possibility of being used in a hybrid vehicle.

In FIG. 5 of the first embodiment, the thickness of the neodymium magnets 22 and 23 is set to about 5.8 mm. The thicker the neodymium magnets 22 and 23, the larger the permeance coefficient, and the larger the magnetic flux density Bd at the operating point that is the intersection of the operating line having the negative permeance coefficient slope and the BH demagnetization curve. It becomes difficult. When the air gap 17 between the stator 15 and the rotor 11 is 0.6 mm, the thickness of the neodymium magnets 22 and 23 is set to about 5.8 mm, thereby preventing magnetic flux short-circuiting of the magnetic fluxes of the neodymium magnets 22 and 23. The ratio of leakage from the holes 24 and 25 is relatively small, and the ratio of leakage across the magnetic flux short-circuit prevention holes 24 and 25 of the magnetic flux accompanying the reverse polarity magnetic field due to the armature current is easily increased. In the magnetic flux short-circuit prevention hole 3 in the conventional example of FIG. 16, the magnetic flux entering the end of the neodymium magnet 2 leaks.

The length L of the center in the radial direction of the magnetic flux short-circuit prevention holes 24 and 25 is 6.0 mm, the average interval D in the orthogonal direction is 3.2 mm, and the (total) width W of the outer magnetic pole faces of the neodymium magnets 22 and 23 is 38 mm. If the difference T between the distance between the first magnet embedding holes 18 and 19 and the total thickness of the soft magnetic metal plates 36 and 37 and the soft magnetic spring plates 38 and 39 is 6.3 mm, the magnetic flux short-circuit prevention hole 24 , 25 and the ratio of magnetoresistance across the neodymium magnets 22 and 23 are (3.2 / 6.0) ÷ 2: (6.3 / 38). Become. The magnetic flux accompanying the reverse polarity magnetic field due to the armature current is branched by the magnetic pole head core 28, and the magnetic flux amount passing through the metal plates 36 and 37 and the neodymium magnets 22 and 23 is 3 minutes of the magnetic flux amount entering the magnetic pole head core 28. 62% which is smaller than 2.

In the rotor of the conventional interior permanent magnet synchronous motor shown in FIG. 16, the width of the outer magnetic pole face of the neodymium magnet with respect to the interval S (area multiplied by the unit length in the stacking direction) of the entrance of the magnetic pole head core 4 The length corresponding to W (area multiplied by the unit length in the stacking direction) is about 0.94 times, and is about 0.93 times in the configuration of Example 1 of the present invention. 16 does not consider the attenuation of the reverse magnetic field due to the armature current in the magnetic pole head core 4 of the conventional example of FIG. 16 and the magnetic pole head core 28 of the first embodiment of FIG. 5, and does not consider the attenuation of the metal plates 36 and 37. 16 is 0.62 × (0.94 / 0.93), and the magnetic pole head of the conventional example shown in FIG. 16 has a magnetic flux density of 0.62 × (0.94 / 0.93). It is 0.63 times the magnetic flux density at the entrance S of the core 4 and the magnetic flux density is smaller than 2/3. However, the magnetic flux density is further reduced in consideration of attenuation of a high frequency component of the reverse polarity magnetic field in the magnetic pole head core due to deeper embedding.

The gap S between the outermost peripheral portion of the magnetic flux short-circuit prevention hole in the conventional example of FIG. 16 and the magnetic flux short-circuit prevention hole in Example 1 of FIG. 5 is the angle formed by the rotation axis center, the thickness of the neodymium magnet, and the rotor If a neodymium magnet having a coercive force Hcj of about 2.4 MA / m (30 kOe) is used in the conventional example on the assumption that the diameters are approximate, the metal plates 36 and 37 are proportionally calculated at room temperature. In Example 1, a neodymium magnet having a coercive force of about 2.4 × 0.63 = 1.51 MA / m (19 kOe) or having a dysprosium content lower than 5 wt% is used. Will be able to. When the magnetic flux density is smaller than two thirds, the heat generation amount multiplied by the magnet area is reduced to about 40% in proportion to the square of the magnetic flux density, and the temperature rise of the neodymium magnet is suppressed. It is compensated that the decrease in the coercive force Hcj of a neodymium magnet having a low dysprosium content increases as the value increases.

FIG. 17 shows the magnetic characteristics depending on the temperature of a conventional neodymium magnet. 17A shows a change in the value of the coercive force Hcj (MA / m) accompanying a change in temperature, and FIG. 17B shows a change in the value of the residual magnetic flux density Br (T: Tesla). The values for neodymium (sintered) magnets with the dysprosium content being zero wt%, ◯ is 2 wt%, Δ is 5 wt%, and * is 10 wt%.

Regarding the coercive force Hcj, at a normal temperature, the coercive force of 5 wt. Becomes 33% (about 1/3).

Regarding the residual magnetic flux density Br at room temperature, the residual magnetic flux density of 5 wt% indicated by △ is 15%, and the residual magnetic flux density indicated by zero wt% indicated by ● is compared to the residual magnetic flux density of 10 wt% dysprosium. Increases by 25%.

In order to increase the coercive force Hcj of a neodymium magnet, it is common to add dysprosium (Dy), a heavy rare earth element, and sinter. For dysprosium content of 0 wt%, 5 wt%, and 10 wt%, the respective coercive forces are 0.8 MA / m (10 kOe), 1.6 MA / m (20 kOe), and 2.4 MA / m (30 kOe). ) The higher the dysprosium content, the lower the coercivity reduction rate when the temperature is higher. In a hybrid vehicle assumed to have a maximum operating temperature of about 200 degrees Celsius, a neodymium magnet having a dysprosium content of 8 wt% to 10 wt% and a coercive force of about 2.4 MA / m (30 kOe) is used.

If the dysprosium content is high, the content of the light rare earth element neodymium (Nd) is lowered accordingly. By replacing part of neodymium in the Nd2Fe14B phase with dysprosium, the magnetocrystalline anisotropy of the main phase is increased, thereby increasing the coercive force. However, the (Nd, Dy) 2Fe14B phase substituted with dysprosium is combined with anti-parallel spins of neodymium and dysprosium, becomes ferrimagnetic, and lowers the magnetization. The difference in the magnitude of the residual magnetic flux density Br of the neodymium magnet not containing dysprosium is 10 wt%, and the former is about 25% smaller than the latter. If the leakage of magnetic flux from the neodymium magnet is intentionally increased and the amount of magnet is not increased, the dysprosium content of the neodymium magnet is greatly reduced to increase the residual magnetic flux density Br, or to increase the temperature of the neodymium magnet. If the magnetic flux density Bd at the operating point, which is the intersection of the operating line with a negative slope of the constant permeance coefficient and the BH demagnetization curve, is not presupposed, the magnitude of the magnet torque is maintained. Can not.

When a 5 wt% neodymium magnet is used in the configuration example of Example 1, the residual magnetic flux density Br is about 15% as compared to the conventional example of FIG. 16 where a neodymium magnet having a dysprosium content of 10 wt% is used. large. When subtracting that the area of the neodymium magnet is reduced by about 1%, there is a margin for increasing the armature flux linkage by about 14%. When the magnet torque is handled with the same magnitude, about 14% of the magnetic flux generated in the neodymium magnets 22 and 23 may be leaked from the magnetic flux short-circuit prevention holes 24 and 25, and the increased leakage is about 13%. For this reason, the magnet torque is not reduced. Furthermore, the magnet torque can be kept large by suppressing the decrease in the residual magnetic flux density Br caused by reducing the temperature rise of the neodymium magnet.

In order to be able to use neodymium magnets 22 and 23 having a dysprosium content lower than 5 wt% or not containing dysprosium, it is possible to use a configuration that further reduces the reverse polarity magnetic field and temperature rise in the neodymium magnet. In addition, it is necessary to solve the problem of 2 that the coercive force Hcj can be improved with a magnet material. In order for the neodymium magnet not to be irreversibly demagnetized, it is effective to combine the correspondence of 1 and the correspondence of 2.

In addition to drilling the magnetic flux short-circuit prevention hole shown in FIG. 1 of the first embodiment, the metal plate for attenuating the reverse polarity magnetic field is added to the outer magnetic pole face of the neodymium magnet. Incorporating a cooling structure. As a countermeasure for 2, the use of a neodymium magnet having a coercive force Hcj of about 1.6 MA / m without containing dysprosium for crystal grain refinement or grain interface control.

FIG. 6 shows an enlarged cross-sectional view of a configuration to which a metal plate for attenuation is added. FIG. 6A is a cross-sectional view taken in a direction perpendicular to the magnetic pole surface of the neodymium magnet 22 in parallel with the rotation axis direction (stacking direction) in FIG. The attenuation due to the skin effect of the metal plate 36 attenuates the reverse polarity magnetic field due to the armature current before applying it to the neodymium magnet 22, thereby reducing the generation of Joule heat in the neodymium magnet 22.

The skin effect is that when an alternating magnetic field is applied to an infinitely approximated conductor from the vertical direction, a large amount of current flows on the surface and decreases exponentially as it goes inside, and flows in a direction that cancels the applied alternating magnetic field. The depth until this current is reduced to 0.368 times the current density on the surface as an eddy current is called a current penetration depth δ, and is expressed by a square root of 1 / (π × μ × σ × f).
μ: Magnetic permeability σ: Conductivity f: Frequency Also, 86% of the heat generation amount is generated between the conductor surface and the current penetration depth δ. When using soft iron with a large magnetic permeability μ, the δ is 1.4 mm at 500 Hz, 0.84 mm at 1 kHz, 0.4 mm at 3 kHz, 0.19 mm at 10 kHz, and the conductivity σ is large but the magnetic permeability is 1. It becomes larger than δ of small copper. However, the magnitude of the magnetic permeability reaches a peak at several kHz or more, and may be reduced by adding a large magnetic flux density of the neodymium magnet.

As the metal plate 36, a soft magnetic metal plate having a thickness of about 0.3 mm is used. When operating at a high rotational speed using reluctance torque, a large reverse polarity magnetic field is inevitably generated, and therefore, a high frequency component of the reverse polarity magnetic field is attenuated in a filter manner by the metal plate 36 before being applied to the neodymium magnet 22. It becomes effective. The permeability μ of the soft magnetic iron plate to which the magnetic flux generated by the magnetic flux density Bd at the operating point on the operating line having a negative permeance coefficient and the BH demagnetizing curve is about a fraction of the maximum magnetic permeability. However, the reverse polarity magnetic field due to the armature current applied to the neodymium magnet 22 by the skin effect is reduced by about 25% at 1 kHz and by about 40% at 3 kHz. Regardless of the frequency, the reverse polarity magnetic field applied to the neodymium magnet 22 is reduced by combining the leakage in the magnetic flux short-circuit prevention hole, which has no heat loss, and the attenuation of the high frequency component in the metal plate 36. Temperature rise is also reduced.

A silicon steel plate (FeSi) may be used as the soft magnetic metal plate. Since the silicon steel sheet has a high magnetic permeability, the current penetration depth δ is small, and the damping effect is large. However, it is hard to cope with bending formation and flexible deformation. In addition, permalloy (FeNi) has a large magnetic permeability but a slightly low saturation magnetic flux density. Therefore, when directly applied to the magnetic pole surface of a neodymium magnet, the magnetic permeability is greatly reduced, and the damping effect becomes relatively small.

The more the reverse polarity magnetic field is attenuated by the metal plate 36, the more Joule heat is generated as the eddy current loss in the metal plate 36. If a configuration in which a large amount of heat generated in the metal plate 36 is conducted to the magnetic pole head core 28 side and asymmetrical heat conduction with little conduction to the neodymium magnet 22 side can be performed, the temperature rise in the neodymium magnet 22 can be further suppressed. it can.

In order to make the metal plate 36 perform asymmetrical heat conduction, a wide peak portion 72 has a large area on the laminated surface of the second outer peripheral side end portion 32 of the magnetic steel plate 12 inside the magnetic pole head core 28. The metal plate 36 is bent and formed so that the narrow valley portion 73 hits the outer magnetic pole surface of the neodymium magnet 22 with a small area. Much of the reverse polarity magnetic field due to the armature current is attenuated by the wide crest portion 72, and the generated Joule heat is largely conducted to the magnetic pole head core 28 side.

The inclined portion 74 from the valley portion 73 to the peak portion 72 of the metal plate 36, which is a soft magnetic iron plate, is magnetically saturated by the magnetic flux from the neodymium magnet 22, and the effective permeability is reduced. Although much reduction in the polar magnetic field cannot be expected, the reverse polarity magnetic field is relatively small because it is located in the space close to the protrusion 75 of the non-ferromagnetic metal plate 13. Accordingly, the attenuation and heat generation of the reverse polarity magnetic field in the inclined portion 74 are small.

The heat generated by the neodymium magnet 22 is radiated from the inclined portions 74 of the non-ferromagnetic metal plate 13 and the metal plate 36 toward the magnetic pole head core 28 by heat conduction. However, if the metal plate 36 generates a lot of heat and is in a high temperature state, the neodymium magnet 22 may maintain a high temperature. Further, when austenitic stainless steel having low thermal conductivity is used for the non-ferromagnetic metal plate 13, the thermal conduction from the neodymium magnet 22 to the magnetic pole head core cannot be increased so much.

In order to avoid a poor heat conduction state in which the neodymium magnet 22 floats from the first inner peripheral side end 38 of the magnetic steel plate 12 due to the centrifugal force during rotation, the inward magnetic pole surface of the neodymium magnet 22 and the first of the magnetic steel plate 12 By disposing the soft magnetic spring plate 40 between the inner peripheral side end portions 38, the heat of the neodymium magnet 22 is radiated from the first inner peripheral side end portion 38 of the magnetic steel plate 12 to the rotor core. Further, rattling of the neodymium magnet 22 in each embedded magnet embedding hole is also suppressed. If priority is given to thermal conductivity and a slight decrease in permeance coefficient is allowed, a copper plate or the like may be used.

The rigidity and spring elasticity of the metal plate 36, which is a soft magnetic iron plate formed by bending, is small with respect to the centrifugal force acting on the neodymium magnet 22 at a high rotational speed. In order to avoid that the bent metal plate 36 is crushed and the shape and spring elasticity cannot be maintained, it is necessary to be supported by the protruding portion 75 of the non-ferromagnetic metal plate 13 in the valley portion 73. Become. From the balance with the permeance coefficient, the amount of protrusion of the non-ferromagnetic metal plate 13 is set to about 0.3 mm. By using a soft magnetic iron plate having a large magnetic permeability and saturation magnetic flux density as the metal plate 36, the thickness of the metal plate 36 does not lower the permeance coefficient.

FIG. 6B shows the metal plate 36 in a plan view in which the length direction is cut out and the center is shortened. On the outer edge of the metal plate 36, an outwardly extending slit 77 is formed at a position 76 facing the protruding portion 75 which is the second outer peripheral side end of the non-ferromagnetic metal plate 13 of FIG. . The position of the metal plate 36 is determined by fitting the slit 77 into the end of the second magnet embedding hole of the non-ferromagnetic metal plate 13.

FIG. 7 is a partially enlarged view of the first embodiment of the present invention, which is different from the metal plate of FIG. FIG. 7A is a cross-sectional view taken in a direction perpendicular to the magnetic pole surface of the neodymium magnet 22 and parallel to the rotational axis direction. The metal plate 78 that attenuates the reverse polarity magnetic field caused by the armature current is formed into a bent shape having a peak portion 79 and a valley portion 80 and is disposed between the outer magnetic pole surface of the neodymium magnet 22 and the magnetic pole head core 28. Are the same. In addition, the valley portion 80 is in contact with the neodymium magnet 22 in a relatively small area, and the flat crest portion 79 is the bottom surface of the magnetic pole head core 28 and the laminated surface of the second outer peripheral side end portion of the magnetic steel plate 12. It is also the same that heat generated in the metal plate 78 is asymmetrically thermally conducted to the magnetic pole head core 28 side by contacting with a large area.

After the assembly, particularly after the neodymium magnet 22 is magnetized, the space where the soft magnetic spring plate 40 is disposed is crushed by the attractive force between the neodymium magnet 22 and the inner peripheral side end portion 38, and the metal plate 78 becomes the pole head. It is necessary to avoid a state of poor heat conduction away from the core 28 from the metal plate 78 to the magnetic pole head core 28 side. The cantilever elastic portions 81 formed at a plurality of locations of the peak portions 79 of the metal plate 78 are configured to be bent and deformed in the same direction as the valley portions 80 from the surface of the metal plate 78, and the difference between the valley portions 80 and the peak portions 79. By making it higher, the tip end portion of the cantilever elastic portion 81 is first brought into contact with the outer magnetic pole surface of the neodymium magnet 22 at the time of assembly and always after the assembly. The state in which the peak portion 79 of the metal plate 78 is in contact with the magnetic pole head core 28 is maintained by the elastic force of the cantilever elastic portion 81, and a large amount of heat generated in the metal plate 78 is transferred to the magnetic pole head core 28 side. Asymmetric heat conduction is maintained.

FIG. 7B shows a plan view of a metal plate 78, which is a soft magnetic iron plate, with the length direction cut away and the width direction shortened. Cantilever elastic portions 81 are formed at a plurality of locations of the peak portions 79 of the metal plate 78. The cantilever elastic portion 81 is bent and deformed, and the vicinity of the tip portion 82 which is a part of the cantilever elastic portion 81 comes into contact with the outer magnetic pole face of the neodymium magnet. It is made to always contact | abut.

FIG. 8 shows a partially enlarged embodiment 1 of the present invention having a configuration in which a plurality of metal plates are stacked. Between the magnetic pole head core 28 and the outward magnetic pole face of the neodymium magnet 22, two layers of metal plates 85 and 86 bent and formed in a wide crest 83 and a narrow trough 84 are disposed. The peak portion 84 of the metal plate 85 and the valley portion of the metal plate 86 that are easily deformed are always in contact with the magnetic pole head core 28 side and the neodymium magnet 22 side. A nonmagnetic metal plate 85 having a high conductivity σ such as copper may be used on the magnetic pole head core 28 side, and a soft magnetic metal plate 86 such as soft iron may be used on the neodymium magnet 22 side.

When the outer magnetic pole face of the neodymium magnet 22 to which a large centrifugal force acts is pressed against the protrusion 75 of the non-ferromagnetic metal plate 13, the relatively thin metal plate 85 and the metal plate 86 that are overlapped are deformed. It is easy to maintain contact between the peak portion 83 and the magnetic pole head core 28 side even if the amount of protrusion of the protrusion 75 of the non-ferromagnetic metal plate 13 changes. The cantilever elastic portion 81 shown in FIG. 7 is provided on the metal plate 86 so that the stacked metal plate 85 and metal plate 86 are always in contact with the magnetic pole head core 28 side and the neodymium magnet 22 side, respectively. It may be. Even if the crests of the metal plate 85 and the metal plate 86 are separated at the time of non-rotation, they are brought into close contact with each other by the centrifugal force acting on the metal plate 85 or the neodymium magnet 22 at a high rotation speed.

FIG. 9 shows the configuration of the end face of the rotor 31 in the first embodiment. The configuration in which air is poured into the through-hole 30 having a relatively large cross-sectional area of the magnetic pole head core 28 that can be increased from the margin of centrifugal strength is mainly described. In FIG. 9A, the end plate 87 does not cover the first magnet embedding holes 18 and 19 that are formed in V-shapes at the respective magnetic poles, and the projection of the fitting portion 68 (not shown hidden). It abuts on the side portion and is fixed by an annular ring 88. With the configuration of the rotor 11 in the state of FIG. 9A, neodymium magnets 22 and 23 are inserted. FIG. 9B shows the neodymium in which the end plate 87 is rotated by an appropriate angle around the rotation axis so that the protruding portion 89 covers part of the first magnet embedding holes 18 and 19 and is inserted. The end surfaces of the magnets 22 and 23 are stopped so that the neodymium magnets 22 and 23 do not jump out.

From the state of FIG. 9A in which the end plate 87 is in contact with the hidden convex fitting portion 68, the end plate 87 is not rotated and in contact with the convex fitting portion 68. ) Is released from the strong pressure applied by the annular ring 88 in the rotation axis direction (stacking direction). Even if the magnetic steel plates 12 and the non-ferromagnetic metal plates laminated alternately have a difference in linear expansion due to a temperature difference, they can be displaced from each other. Further, no large residual stress remains on the magnetic steel sheet, so that the magnetic properties are not deteriorated.

When the convex fitting part 68 is too high, the convex fitting part 68 coming out from the escape hole is lowered by placing a non-ferromagnetic metal plate having a relief hole on the end face, When the end plate 87 that has been in contact is rotated and released from the fitting portion 68 and released from the strong pressure state, it is possible to prevent the magnetic steel plate 12 and the non-ferromagnetic metal plate from becoming excessively loose.

As shown in FIG. 9B, a portion for forcibly taking in air is provided in the central through hole 30 of the magnetic pole head core 28. An air intake portion 91 having an opening 90 in the main rotation direction is provided in a part of the protruding portion 89 of the end plate 87. The rotor core 31 is lower than the temperature of the stator teeth (not shown) only by relying on heat conduction by air that flows at a relatively high speed in the air gap between the stator (not shown) and the rotor 11. Since it is difficult to make the temperature low, a method of cooling the through hole 30 by introducing air is introduced.

During the rotation of the rotor 11, the air that has been taken in from the opening 90 of the air intake portion 91 is forced to flow into the through hole 30. Air flowing as a turbulent flow through the through hole 30 receives heat from the magnetic pole head core 28. The air intake portion 91 may be formed by using a thin plate material instead of a part of the thick end plate 87, thereby reducing windage loss and wind noise. As the magnetic pole head core 28 is cooled, the temperature rise of the neodymium magnets 22 and 23 is reduced.

FIG. 10 shows a part of the cooling configuration of the first embodiment of the present invention. Although different from the configuration around the rotation axis in the rotor 11 up to FIG. 4 in the first embodiment, the same reference numerals are given to corresponding portions because the rotor core has a common configuration. The stator and rotor are housed in a case closed from the outside air for waterproofing, dustproofing and soundproofing. In order to force air to flow into the through hole 30 formed in the magnetic pole head core 28 of each magnetic pole of the rotor core 31 in which the magnetic steel plate and the non-ferromagnetic metal plate are laminated in a hybrid configuration, the air is opened in the main rotation direction. Air intake portions 93 having portions 92 are provided at a plurality of locations on the end plate 94 and are fixed to one end surface 95 of the rotor 11.

The air intake portion 93 is disposed at a position covering the through hole 30, and the air taken in from the opening 92 of the air intake portion 93 as the rotor 11 rotates is forced to flow into the through hole 30 as turbulent flow. By flowing, heat is absorbed from the magnetic pole head core 28 and discharged from the other end face 96. In order to cool the neodymium magnets 22 and 23, the temperature of the air entering the air intake portion 93 needs to be relatively low.

The heat exchanging portion 99 disposed to face the other end surface 96 of the rotor 11 is displayed separated from the other end surface 96 of the rotor 11 in parallel in the axial direction. The heat exchanging portion having fins 98 formed of a part of a vortex shape in which air discharged from the through hole 30 and having momentum in the rotational direction converges from the outside to the central direction in the main rotational direction with the center of the rotational axis as the rotational symmetry center. Heat is exchanged by hitting 99. The direction of the air guided to the inside 101 along the vortex-shaped groove 100 is changed, passes through the inner side of the rotor 11, is returned to one end face 95 of the rotor 11, and passes through the through hole from the air intake portion 93. The cycle of reentering 30 is repeated. Circulation is mainly performed inside the diameter of the rotor 11.

FIG. 11 is a cross-sectional view of the cooling configuration of the first embodiment of the present invention. The stator 15 and the rotor 11 are disposed in cases 97 and 109 which are closed for waterproofing, dustproofing and soundproofing. An air intake portion 93 is fixed at a position covering the through hole 30 on one end face 95 of the rotor 11, and a heat exchanging portion 99 independent of the rotation of the rotor 11 is disposed facing the other end face 96. Air that enters from the opening 92 and flows into the through hole 30 by the air intake portion 93 and hits the heat exchange portion 99 passes through the reflux hole 103 provided inside the rotor hub 102 and hits the heat exchange portion 108. The flow is changed from the inside to the outside, and flows into the through-hole 30 from the air intake portion 93 along the fins 105 and the grooves 106 to be refluxed.

An oil passage 107 for cooling is provided in a case 97 in which the heat exchanging unit 99 is integrated so that the heat exchanging unit 99 that is exposed to the fin 98 with a large area is maintained at a relatively low temperature. It is done. Similarly, in order to cool the heat exchange unit 108 integrated with the case 109 in which the heat exchange unit 108 is integrated with the outside air so that the heat exchange unit 108 that is exposed to the fin 105 in a large area is maintained at a relatively low temperature. You may provide the outer fin 110 protruded outside. Furthermore, a thermoelectric conversion element may be attached to the case 109. Of course, a water cooling or liquid cooling (oil cooling) configuration may be used.

Air is prevented from circulating toward the stator 15 outside the diameter of the rotor 11. A circular wall surface 108 is provided at a height equal to or higher than the height of the fin 98 along the vortex-shaped outer peripheral portion of the heat exchange unit 99. Similarly, a circular wall surface 104 is provided above the height of the fin 105 along the vortex-shaped outer peripheral portion of the heat exchange unit 108. By reducing the ratio of the amount of air flowing toward the stator 15, the influence of heat of copper loss and iron loss generated in the stator 15 is reduced, and the periphery of the neodymium magnet is intensively cooled.

FIG. 12 shows a part of the cooling configuration of the first embodiment of the present invention. The heat exchanging portion 108 disposed opposite to one end face 95 of the rotor 11 is developed away from the one end face 95 from the actual position in order to show the whole. The heat exchanging unit 108 is provided in the case 109 and has fins 105 and grooves 106 formed by a part of a vortex shape that diverges from the center to the outside in the main rotation direction with the center of the rotation axis as the center of rotational symmetry. Air flows from the inside to the outside along the plurality of fins 105 and the grooves 106, and most of the air enters the through hole 30 again from the air intake portion 93. In order to guide the air flow, it is desirable that the inside of the circular wall surface 104 of the heat exchanging portion 108 and the bottom portion of the groove 106 are connected in an R curved shape.

By giving a centrifugal strength strength using a rotor having a hybrid laminated structure as in the present invention, the magnetic pole head core can be enlarged even at a high rotational speed, and a neodymium magnet can be embedded deeply. The magnetic flux short-circuit prevention hole inevitably elongated in the radial direction divides and leaks the magnetic flux accompanying the reverse polarity magnetic field due to the armature current without heat loss regardless of the frequency, and reduces the reverse polarity magnetic field applied to the neodymium magnet. A metal plate that performs asymmetric heat conduction is disposed on the outer magnetic pole face of the neodymium magnet to attenuate the high frequency component reverse polarity magnetic field with heat loss, further reducing the reverse polarity magnetic field before being applied to the neodymium magnet. A large amount of heat generated in the metal plate is asymmetrically conducted to the magnetic pole head core side, so that the temperature rise of the neodymium magnet is suppressed. The temperature rise of the neodymium magnet is suppressed by the air circulation through the heat exchange part inside the through hole with a large cross-sectional area provided in the magnetic pole head core that can be increased by improving the centrifugal strength and the rotor. The By a plurality of means based on the centrifugal strength, a neodymium magnet having a dysprosium content lower than 5 wt% can be used for a rotor of an embedded magnet synchronous motor for high rotational speed applications such as a hybrid vehicle. Then, by using a neodymium magnet whose coercive force Hcj is improved by crystal grain refinement or grain interface control, a neodymium magnet not containing dysprosium can be used.

FIG. 13 shows a second embodiment of the rotor of the interior permanent magnet synchronous motor according to the present invention in a part of the enlarged end face. Based on having anti-centrifugal strength, the neodymium magnet is embedded deeply, the reverse polarity magnetic field due to the armature current applied to the neodymium magnet is reduced, and the temperature rise is suppressed. Each magnetic pole is different from the first embodiment in that a parallel neodymium magnet 111 is embedded in each magnetic pole, and the magnetic pole head core 112 does not have a through hole. In order to adopt the cooling structure of the rotor shown in FIGS. 10 to 12 of the first embodiment in the same manner and to effectively cool the neodymium magnet, an elliptical penetration is formed in the center of the magnetic pole head core 112. A hole may be drilled.

The rotor core 113 is formed by laminating a laminated portion of a plurality of magnetic steel plates 114 and a non-ferromagnetic metal plate 115 that is mostly concealed in the magnetic steel plates 114 so that the shapes of the outer periphery and the inner periphery are substantially the same. The rotor 117 is formed by being fitted to the hub 116. The rotor 117 has an air gap 120 between the stator 118 and the stator teeth 119 of the stator 118. The magnetic steel plate 114 and the non-ferromagnetic metal plate 115 are provided with the main portions of the first magnet embedding hole 121 and the second magnet embedding hole 122, both of which are punched by punching, so that the energy product is increased. A large neodymium magnet 111 is embedded.

The second outer peripheral end portion 123 of the second magnet embedding hole 122 of the non-ferromagnetic metal plate 115 is rotated more than the first outer peripheral end portion 125 of the first magnet embedding hole 121 of the magnetic steel plate 114. Is protruded in the central direction where the magnet is located, and is in contact with the outer magnetic pole surface of the neodymium magnet 111 with a metal plate 126 shown in cross section therebetween. In FIG. 13, the second outer peripheral end 123 is shown protruding greatly from the first outer peripheral end 125, but the protruding amount is about 0.3 mm at room temperature.

The neodymium magnet 111 on which the centrifugal force acts when the rotor 117 rotates is held by the second outer peripheral end 123 protruding through the metal plate 126 therebetween. The non-ferromagnetic metal plate 115 receiving the centrifugal force of the neodymium magnet 111 and the centrifugal force acting on itself is formed into an annular shape having a wide and large tensile strength from the outer periphery, and adjacent second magnet embedding holes 122, 127, And 122, 128, which are concealed under the laminated magnetic steel plate 114, and are integrated into an annular portion having a wide and large tensile strength from the inner periphery through a wide radial support portion. Thus, even when a sufficient safety factor of strength is obtained, the ratio of the laminated thickness of the non-ferromagnetic metal plate 115 can be reduced.

Magnetic flux short-circuit prevention holes 129 and 130 punched only in the magnetic steel plate 114 are formed continuously from the first magnet embedding hole 121 and extended in the radial direction to the bridge portions 131 and 132 located on the outer periphery. The magnetic flux short-circuit prevention holes 129 and 130 are formed to intentionally leak a magnetic flux accompanying a reverse polarity magnetic field due to an armature current by breaking a magnetic short circuit in a part of the magnetic steel plate 114, but from the neodymium magnet 111. It is also required not to leak much magnetic flux.

The neodymium magnet 111 retains the centrifugal force and acceleration force acting during rotation, and maintains its position. Therefore, the neodymium magnet 111 is formed with the outer magnetic pole surface of the second magnet embedding hole 122 punched into the non-ferromagnetic metal plate 115. Positioned on the side. The sides of the neodymium magnet 111 with the chamfered corners are side ends that continue from the second outer peripheral side end 123 of the second magnet embedding hole 122 through the arc-shaped corners, and the gap is reduced. Positioned. Even when the corners of the neodymium magnet are not chamfered, it is possible to hold and position the outer magnetic pole face and side face of the neodymium magnet with a non-ferromagnetic metal plate in a shape that can be punched.

The inward magnetic pole surface of the neodymium magnet 111 is in contact with the first inner peripheral side end portion 134 of the first magnet embedding hole 121 with the soft magnetic spring plate 133 interposed therebetween. A second inner peripheral side end portion indicated by a broken line in the second magnet embedding hole 122 of the non-ferromagnetic metal plate 115 is placed so as to be recessed in the center direction from the first inner peripheral side end portion 134.

The outer magnetic pole surface and the inner magnetic pole surface of the neodymium magnet 111 have a small gap between the first outer peripheral end portion 125 and the first inner peripheral end portion 134 of the magnetic steel sheet 114 that can be punched in parallel. Therefore, the decrease in permeance coefficient is small, and the magnetic flux density Bd at the operating point in the BH demagnetization curve of the neodymium magnet 111 is used effectively. There is also an effect to avoid irreversible demagnetization. This is because, as in the case of positioning a neodymium magnet with a magnetic steel plate as in the conventional example of FIG. 16, the gap between the pole face at the end of the neodymium magnet and the rotor core 113 is in millimeters due to punching restrictions. It is advantageous compared to the resulting configuration.

The neodymium magnet 111 is embedded deep inside the magnetic pole head core 112 and is largely separated from the tip of the stator tooth 119 of the stator 118, so that the armature winding is wound across the plurality of stator teeth 119. The local magnetic field generated by this current is weakened and reduced when applied to the neodymium magnet 111.

FIG. 14 is an exploded configuration diagram of the rotor core in the second embodiment of the present invention. The ratio of the laminated thickness of the magnetic steel plates is set to be larger than the ratio of the laminated thickness of the non-ferromagnetic metal plates. It is necessary to prevent magnetic saturation from occurring in the rotor core with the magnetic flux of the neodymium magnet embedded in the rotor core or the magnetic flux generated by the armature current. The ratio of the lamination thickness of the non-ferromagnetic metal plate that holds the neodymium magnet from centrifugal force is the shape and material strength of the non-ferromagnetic metal plate, the mass and embedding position of the neodymium magnet, the outer diameter of the rotor, the maximum rotation speed, and Determined by considering the safety factor.

FIG. 14A shows the rotor core 113 in a stacked state fitted to the rotor hub 116 and the members to be embedded. 14 (b) and 14 (c) show a unit configuration before being stacked in a hybrid configuration, and FIG. 14 (b) shows 10 pieces of 0.35-mm-thick magnetic steel plates 135, 0.5 The millimeter-thick non-ferromagnetic metal plate 136 has a single unit configuration, and FIG. 14C shows 21 pieces of 0.3 mm-thick magnetic steel plates 137 and 0.3 mm-thick non-ferromagnetic metal plates 138. Indicates a unit configuration in which three pieces are stacked, and individual unit configurations are alternately stacked to form a rotor core 113 having a hybrid configuration shown in FIG. The lamination thickness ratio of the magnetic steel plates 135 and 137 and the non-ferromagnetic metal plates 136 and 138 in the unit configuration is about 7 to 1, respectively.

The outer diameter of the rotor 117 in FIG. 14A is 150 millimeters, the maximum rotational speed is 14000 rpm, the section of the neodymium magnet 111 is 5.7 millimeters × 37 millimeters, and the embedding depth at the circumferential end of the neodymium magnet 111 is as follows. Is 9.0 millimeters, and the width of the bridge portions 131 and 132 is 2.4 millimeters. In FIGS. 14 (b) and 14 (c), a magnetic material using a silicon steel sheet having a silicon content of 3 wt% is used. It is an example of the ratio of the laminated thickness in the steel plates 135 and 137 and the non-ferromagnetic metal plates 136 and 138 using the austenitic stainless steel plate.

The magnetic pole head cores 139 and 140 formed by punching the magnetic steel plates 135 and 137 are held by narrow bridge portions at both ends of the outer peripheral portion, and the wide magnetic pole cores 141, 142, and 143, 144 are interposed therebetween. It is integrated with a wide and annular back core 145, 146. Magnetic flux short-circuit prevention holes 147, 148, and 149, 150 are formed in contact with the circumferential ends of the magnetic pole head cores 139, 140 for breaking a magnetic short-circuit in part.

In FIG. 14A, the neodymium magnet divided into a first magnet embedding hole 121 and a second magnet embedding hole 122 drilled at a position where the magnetic steel plate and the non-ferromagnetic metal plate overlap. 111 is inserted. Between the outer magnetic pole surface of the neodymium magnet 111, the first outer peripheral end of the first magnet embedding hole 121, and the second outer peripheral end of the second magnet embedding hole 122 The metal plate 126 is disposed. A soft magnetic spring plate 133 is disposed between the inward magnetic pole surface of the neodymium magnet 111 and the first inner peripheral end of the first magnet embedding hole 121.

The metal plate 126 attenuates the reverse polarity magnetic field caused by the armature current by the skin effect to reduce the reverse polarity magnetic field applied to the neodymium magnet 111, thereby reducing the generation of Joule heat in the neodymium magnet 111. The metal plate 126 that has a large area on the magnetic pole head core 112 side and a small area on the outer magnetic pole surface side of the neodymium magnet 111 has a wide peak so that heat generated by the metal plate is asymmetrically conducted. It is bent and molded into a valley and a narrow valley. Further, positioning is performed by fitting an outwardly extending slit formed on the outer edge of the metal plate 126 into the non-ferromagnetic metal plate, and the valley of the metal plate 126 is used for embedding the second magnet of the non-ferromagnetic metal plate. The second outer peripheral end of the hole 122 is aligned.

For the metal plate 126, for example, a soft magnetic iron plate having a thickness of about 0.3 mm is used. Magnetic flux due to the reverse polarity magnetic field due to the armature current is partially branched and leaked by the magnetic flux short-circuit prevention holes 129 and 130 without heat loss regardless of the frequency, and further applied to the neodymium magnet 111 before being applied to the soft magnetic metal plate 126. High frequency components are attenuated with heat loss.

The magnetic pole head core 112 has a large slope at both ends in the circumferential direction even if a decrease in saturation magnetic flux density of about 12% due to the non-ferromagnetic metal plates laminated as a part of the hybrid configuration occurs on average. Therefore, the magnetic saturation due to the q-axis magnetic flux is slowed down, the decrease in q-axis inductance is suppressed, and high efficiency is achieved in a wide operating range. Can be obtained.

The ratio of the amount of magnetic flux leaking across the magnetic flux short-circuit prevention holes 129 and 130 to the amount of magnetic flux entering the metal plate 126 and the neodymium magnet 111 after the magnetic flux due to the reverse polarity magnetic field due to the armature current enters the magnetic pole head core 112 is The magnetic resistance in parallel with the magnetic flux short-circuit prevention holes 129 and 130 is inversely proportional to the ratio of the magnetic resistance straddling the neodymium magnet 111.

As a configuration example of the second embodiment, the radial center length L of the magnetic flux short-circuit prevention holes 129 and 130 in FIG. 13 is 6.0 mm, the average interval D in the orthogonal direction is 3.2 mm, and the outer magnetic pole of the neodymium magnet 111 The width W of the surface is 35 mm, the difference T between the distance between the first magnet embedding holes 121 and the total thickness of the metal plate 126 and the soft magnetic spring plate 133 is 6.3 mm, and the distance between the entrances of the magnetic pole head core 112 The distance S between the outermost peripheral portions of the magnetic flux short-circuit prevention holes 129 and 130 (area multiplied by the unit length in the stacking direction) is 40 mm, and the amount of magnetic flux accompanying the reverse polarity magnetic field due to the armature current entering the distance S is Φ To do.
Φ × {(D / 2L) / (D / 2L + T / W)} = 0.60 × Ф <(2/3) × Ф
The amount of magnetic flux applied to the neodymium magnet 111 is smaller than two thirds of the amount of magnetic flux applied to the gap S at the entrance of the magnetic pole head core 112 without considering the attenuation at the metal plate 126.

Compared with the magnetic flux density in the neodymium magnet 2 of the conventional example of FIG. 16 in which a neodymium magnet having a dysprosium content of 8 wt% to 10 wt% is used, the magnetic flux density in the neodymium magnet 111 is smaller than two thirds. Since the temperature rise of the neodymium magnet 111 is largely suppressed, it leads to the possibility of using a neodymium magnet having a dysprosium content rate lower than 5 wt% for an embedded magnet synchronous motor such as a hybrid vehicle. However, it is assumed that the opening angle S between the entrances and the center of the rotation axis, the thickness of the neodymium magnet, and the diameter of the rotor are approximate. Further, it is assumed that the magnetic flux due to the reverse polarity magnetic field entering the end of the neodymium magnet 2 leaks into the magnetic flux short-circuit prevention hole 3 of the conventional example of FIG.

As in the second embodiment, the magnetic pole head core can be enlarged and the neodymium magnet can be embedded deeply even at a high rotational speed by giving a centrifugal force strength by using a hybrid rotor. The magnetic flux short-circuit prevention hole elongated in the radial direction branches and leaks the magnetic flux accompanying the reverse polarity magnetic field caused by the armature current without heat loss regardless of the frequency, thereby reducing the reverse polarity magnetic field applied to the neodymium magnet. A metal plate that performs asymmetric heat conduction is disposed on the outer magnetic pole face of the neodymium magnet to attenuate the high frequency component reverse polarity magnetic field with heat loss, further reducing the reverse polarity magnetic field before being applied to the neodymium magnet. A large amount of heat generated in the metal plate is asymmetrically conducted to the magnetic pole head core side, so that the temperature rise of the neodymium magnet is suppressed. If necessary, the temperature of the neodymium magnet is increased by air circulation through the heat exchange section inside the rotor and the through hole provided in the magnetic pole head core, which can be increased by improving the strength against centrifugal force. It is suppressed. By a plurality of means based on the high centrifugal strength, a neodymium magnet having a dysprosium content lower than 5 wt% can be used for a rotor of an embedded magnet synchronous motor for high rotational speed applications such as a hybrid vehicle. Furthermore, it becomes possible to use a neodymium magnet not containing dysprosium by using a neodymium magnet whose coercive force Hcj is improved by crystal grain refinement or grain interface control.

Embodiment 3 of the rotor of the interior permanent magnet synchronous motor of the present invention is shown by a partially enlarged end face in the stacking direction of FIG. The position of the magnetic flux short-circuit prevention hole is different from that of Example 1, and the stator is shown in a concentrated winding configuration. Magnetic flux short-circuit prevention holes 151 and 152 for partially breaking the magnetic short circuit of the magnetic steel sheet 155 are the first magnet embedding holes 156 and 157 of the magnetic steel sheet 155 into which the neodymium magnets 153 and 154 are inserted. It is formed to extend in the radial direction from the bridge portions 168 and 169 continuing from the outer peripheral side end portions 164 and 165 to the outer periphery of the rotor 158.

The non-ferromagnetic metal plate 159 hidden by the laminated magnetic steel plates 155 and having the inner periphery and the outer periphery in common with the magnetic steel plates 155 has an annular configuration that is wide from the outer periphery and has a high tensile strength. In addition, second magnet embedding holes 160 and 161 overlapping the first magnet embedding holes 156 and 157 are provided. Furthermore, the second outer peripheral side ends 162 and 163 of the second magnet embedding holes 160 and 161 are more rotationally rotated than the first outer peripheral end portions 164 and 165 of the first magnet embedding holes 156 and 157. The configuration and effect of holding the neodymium magnets 153 and 154 on which the centrifugal force acts are interposed between the soft magnetic metal plates 166 and 167 that are protruded in the center direction and bent and formed in the same manner as in the first embodiment. is there.

After the magnetic flux due to the reverse polarity magnetic field due to the armature current enters the magnetic pole head core 170, the amount of magnetic flux leaking across the magnetic flux short-circuit prevention holes 151 and 152, and the magnetic flux entering the metal plates 166 and 167 and the neodymium magnets 153 and 154 The ratio of the amount is inversely proportional to the ratio of the parallel magnetic resistance of the magnetic flux short-circuit prevention holes 151 and 152 and the magnetic resistance straddling the neodymium magnets 153 and 154.

The length L of the center in the radial direction of the magnetic flux short-circuit prevention holes 151 and 152 from the bridge portions 168 and 169 to the outer periphery is 6.0 mm, the average interval D in the orthogonal direction is 3.2 mm, and the outer magnetic pole surface of the neodymium magnets 153 and 154 The total width W is 37 mm, the difference T between the distance between the first magnet embedding holes 156 and 157 and the total thickness of the metal plates 166 and 167 and the soft magnetic spring plates 172 and 173 is 6.3 mm, and the magnetic flux The distance S between the outermost peripheral portions of the short-circuit prevention holes 151 and 152 (area multiplied by the unit length in the stacking direction) is set to 40 mm, which is accompanied by a reverse polarity magnetic field caused by an armature current entering the distance S at the entrance of the magnetic pole head core 170. Let Φ be the amount of magnetic flux.
Φ × {(D / 2L) / (D / 2L + T / W)} = 0.61 × Φ <(2/3) × Φ
And the amount of magnetic flux applied to the neodymium magnets 153 and 154 is smaller than two thirds of the amount of magnetic flux applied to the interval S between the entrances of the magnetic pole head core 170 without considering attenuation at the metal plates 166 and 167. .

Compared with the magnetic flux density in the neodymium magnet 2 of the conventional example of FIG. 16 in which a neodymium magnet having a dysprosium content of 8 wt% to 10 wt% is used, the magnetic flux density in the neodymium magnets 153 and 154 is smaller than two thirds. Become. Since the rise in temperature of the neodymium magnets 153 and 154 is suppressed, a neodymium magnet having a dysprosium content lower than 5 wt% is led to the possibility of being used in an embedded magnet synchronous motor such as a hybrid vehicle. However, it is assumed that the opening angle S between the entrances and the center of the rotation axis, the thickness of the neodymium magnet, and the diameter of the rotor are approximate.

As in the third embodiment, by providing a centrifugal strength strength using a rotor having a hybrid laminated structure, the magnetic pole head core can be enlarged even at a high rotational speed, and a neodymium magnet can be embedded deeply. The magnetic flux accompanying the reverse polarity magnetic field due to the armature current is inevitably branched and leaked without heat loss regardless of the frequency in the magnetic flux short-circuit prevention hole inevitably elongated in the radial direction, thereby reducing the reverse polarity magnetic field applied to the neodymium magnet. A metal plate that conducts asymmetrical heat conduction is disposed on the outer magnetic pole face of the neodymium magnet to attenuate the high-frequency component reverse polarity magnetic field with heat loss, thereby further reducing the reverse polarity magnetic field before being applied to the neodymium magnet. In addition, the heat generated in the metal plate is largely asymmetrically transferred to the magnetic pole head core, and can be increased by improving the strength of centrifugal force. By circulating, the temperature rise in the neodymium magnet is further suppressed. By a plurality of means based on having centrifugal strength, a neodymium magnet having a dysprosium content lower than 5 wt% can be used for a rotor of an embedded magnet synchronous motor for high rotational speed applications such as a hybrid vehicle. Furthermore, it becomes possible to use a neodymium magnet not containing dysprosium by using a neodymium magnet whose coercive force Hcj is improved by crystal grain refinement or grain interface control.

Provided with embedded magnet synchronous motors equipped with neodymium magnets with a low dysprosium content by controlling the reverse polarity magnetic field and temperature rise for hybrid vehicle applications.

Provided is an interior permanent magnet synchronous motor with a high efficiency and a wide operating range by reducing iron loss and suppressing q-axis inductance reduction.

Provided is an embedded magnet synchronous motor that can maintain a large magnet torque by reducing the dysprosium content and suppressing temperature rise.

By increasing the lamination thickness ratio of the non-ferromagnetic metal plate, an embedded magnet synchronous motor for high rotational speed applications can be provided.

11, 117, 158 Rotor 12, 114, 135, 137, 155 Magnetic steel plate 13, 115, 136, 138, 159 Non-ferromagnetic metal plate 14, 102, 116 Rotor hub 15, 120 Stator 16, 50, 51 119 Stator teeth 17, 120 Air gaps 18, 19, 121, 156, 157 First magnet embedding holes 20, 21, 122, 160, 161 Second magnet embedding holes 22, 23, 111, 153, 154 Neodymium magnets 24, 25, 129, 130, 151, 152 Magnetic flux short-circuit prevention holes 26, 27, 131, 132, 168, 169 Bridge portions 28, 112, 170 Magnetic pole head core 29 First radial bridge portion 30, 171 Through holes 31, 113, 174 Rotor cores 32, 33, 123, 162, 163 Second outer peripheral side end portions 34, 35, 12 164,165 First outer peripheral side end portions 36, 37, 78, 85, 86, 166, 167 Metal plates 38, 39, 134 First inner peripheral side end portions 40, 41, 133, 153, 154, 172 , 173 Soft magnetic spring plate 42 Second radial bridge portion 47, 67 Key 48 Key groove 49 Rotating shaft 52, 53, 141, 142, 143, 144 Magnetic pole core 54, 140, 146 Back core 68 Fitting portion 69 Relief hole 72, 79, 83 Mountain part 73, 80, 84 Valley part 77 Slit part 81 Cantilever elastic part 87, 94 End plate 88 Annular ring 90, 92 Opening part 91, 93 Air intake part 97, 109 Case 98, 105 Fins 99 and 108 Heat exchanger 103 Recirculation hole 107 Oil passage 110 Outer fin

Claims (23)

In a rotor of an embedded magnet synchronous motor in which rare earth magnets are embedded in each magnetic pole of a rotor core made of laminated magnetic steel plates,
Rare earth magnets are inserted into the through hole for magnet embedding formed by forming the first magnet embedding hole and the second magnet embedding hole on the magnetic steel plates and non-ferromagnetic metal plates stacked alternately. Centrifugation is performed only by the second outer peripheral end portion of the second magnet embedding hole that is embedded and protrudes in the center direction where the rotation shaft is located from the first outer peripheral end portion of the first magnet embedding hole. A rare earth magnet on which a force acts is held, and a magnetic flux short-circuit prevention hole extending in the radial direction from the vicinity of the circumferential end of the first magnet embedding hole is formed.
The rotor of the interior permanent magnet synchronous motor characterized by the above-mentioned. Neodymium magnet is used for the rare earth magnet,
The rotor of the interior permanent magnet synchronous motor of Claim 1 characterized by the above-mentioned. The neodymium magnet at the second outer peripheral side end and side end of the second magnet embedding hole drilled in the non-ferromagnetic metal plate and at the side end of the second radial bridge portion The outward magnetic pole face and side of the
The rotor of the interior permanent magnet synchronous motor of Claim 2 characterized by the above-mentioned. The magnetic steel plate and the non-ferromagnetic metal plate are alternately bent and bent between the concave and convex laminated surface of the magnetic pole head core and the outer magnetic pole surface of the neodymium magnet. A metal plate is disposed, and the peak portion is in contact with the continuous surface of the first outer peripheral side end portion, and the valley portion is in contact with the second outer peripheral side end portion of the non-ferromagnetic metal plate,
The rotor of the interior permanent magnet synchronous motor of Claim 2 or Claim 3 characterized by the above-mentioned. The peak is flat with a large area, and the valley is small.
The rotor of the interior permanent magnet synchronous motor of Claim 4 characterized by the above-mentioned. A configuration in which the cantilevered elastic portions formed at a plurality of locations of the metal plate protrude from the flat surface of the peak portion of the metal plate in the direction of the valley portion to be larger than the difference in height between the peak portion and the valley portion. To be
The rotor of the interior permanent magnet synchronous motor of Claim 4 or Claim 5 characterized by the above-mentioned. The metal plate is a soft magnetic metal plate,
The rotor of the interior permanent magnet synchronous motor according to any one of claims 4 to 6, wherein the rotor is an embedded magnet synchronous motor. A plurality of the bent metal plates are arranged to be stacked;
The rotor of the interior permanent magnet synchronous motor according to any one of claims 4 to 7, wherein the rotor is an embedded magnet synchronous motor. An outwardly extending slit is formed at the outer edge of the metal plate at a position facing the second outer peripheral side end of the non-ferromagnetic metal plate where the valley of the metal plate overlaps.
The rotor of the interior permanent magnet synchronous motor according to any one of claims 4 to 8, wherein the rotor is an embedded magnet synchronous motor. The amount of protrusion at room temperature in the center direction of the second outer peripheral end of the non-ferromagnetic metal plate with respect to the first outer peripheral end of the magnetic steel plate is the first outer peripheral side from the center of the rotating shaft. More than the sum of the linear expansion difference at the temperature difference between the room temperature and the maximum operating temperature with respect to the length to the end and the length to the second outer peripheral end, the tolerance of machining, and the tolerance of assembly To be
The rotor of the interior permanent magnet synchronous motor according to claim 1, wherein the rotor is a permanent magnet synchronous motor. A magnetic flux short-circuit prevention hole is drilled continuously extending from the circumferential end of the first magnet embedding hole drilled in the magnetic steel plate and extending radially to the bridge portion located on the outer circumference.
The rotor of the interior permanent magnet synchronous motor according to any one of claims 1 to 4, wherein the rotor is embedded. In the vicinity of the circumferential end of the first magnet embedding hole, it is formed continuously from the first outer peripheral end and located near the circumferential end of the first magnet embedding hole. The magnetic flux short-circuit prevention hole is formed by extending in a radial direction from the bridge portion to the outer periphery,
The rotor of the interior permanent magnet synchronous motor according to any one of claims 1 to 4, wherein the rotor is embedded. The length L of the radial center of the magnetic flux short-circuit prevention hole from the bridge portion located on the outer periphery to the position where the approximate width ends, the average interval D in the orthogonal direction, the width W of the outer magnetic pole surface of the neodymium magnet, and the first The difference T between the interval between one magnet embedding hole and the thickness of the soft magnet including the metal plate in the first magnet embedding hole is defined as T, which is the maximum of the two magnetic flux short-circuit prevention holes in the magnetic pole head core. The distance S between the outer peripheral portions, and the amount of magnetic flux Φ associated with the reverse polarity magnetic field due to the armature current that enters the distance S, the condition,
Φ × {(D / 2L) / (D / 2L + T / W)} <(2/3) × Φ
Configured to meet,
The rotor of the interior permanent magnet synchronous motor according to claim 11. The length L of the center in the radial direction of the magnetic flux short-circuit prevention hole extending in the radial direction from the bridge portion that continues from the first outer peripheral end to the outer periphery, the average interval D in the orthogonal direction, and the outward magnetic pole of the neodymium magnet The surface width W and the difference T between the interval between the first magnet embedding holes and the thickness of the soft magnet including the metal plate in the first magnet embedding holes, and two locations on the magnetic pole head core The magnetic flux amount Φ associated with the reverse polarity magnetic field due to the armature current entering the interval S and the interval S of the outermost peripheral portion of the magnetic flux short-circuit prevention hole,
Φ × {(D / 2L) / (D / 2L + T / W)} <(2/3) × Φ
Configured to meet,
The rotor of the interior permanent magnet synchronous motor according to claim 12. The magnetic steel plates having the same shape uneven fitting portions of the same shape in a plurality of places are overlapped and integrated, and a relief hole is provided at a position facing the fitting portion in the non-ferromagnetic metal plate,
The rotor of the interior permanent magnet synchronous motor according to claim 1, wherein the rotor is a permanent magnet synchronous motor. A key portion protruding from a circular inner peripheral portion of the magnetic steel plate and the non-ferromagnetic metal plate is fitted into a key groove provided at a corresponding position on the outer peripheral portion of the rotor hub, and the diameter of the rotor core And an end plate having a plurality of projecting portions that reach a part of the first magnet embedding hole in the outer direction of the diameter and are in contact with the end face of the rotor core from the outside. Fixed with an annular ring,
The rotor of the interior permanent magnet synchronous motor according to any one of claims 1, 2, and 15. An end plate in which the first magnet embedding hole and the second magnet embedding hole disposed on the end surface of the rotor core so as to overlap each other at equal angular intervals in the circumferential direction are in contact with the end surface A state of facing the end plate and a state of not facing the end plate are selected by rotation at a certain angle of
The rotor of the interior permanent magnet synchronous motor of Claim 16 characterized by the above-mentioned. On the end face of the rotor core, a state is selected in which the convex portions of the fitting portions formed at equal angular intervals in the circumferential direction are in contact with the end plate by rotation at a constant angle. ,
The rotor of the interior permanent magnet synchronous motor of Claim 16 characterized by the above-mentioned. An air intake portion having an opening in the main rotation direction of the rotor is fixed at a position of a through hole around the neodymium magnet in the end face of the rotor core.
The rotor of the interior permanent magnet synchronous motor according to any one of claims 1 to 3, wherein The stator and the rotor are closed with a case from the outside air, and air is circulated through the heat exchange part in the middle of the through hole and the rotor,
The rotor of the interior permanent magnet synchronous motor of Claim 19 characterized by the above-mentioned. The heat exchanging portion has a plurality of fins made of a part of a vortex shape with the center of the rotation axis as a rotational symmetry center, and is disposed to face the end face of the rotor;
The rotor of the interior permanent magnet synchronous motor of Claim 20 characterized by the above-mentioned. The terminals of the armature winding are electrically interrupted at a cycle shorter than a half cycle defined by the inverse of the product of the number of magnetic poles of the rotor and the rotational speed.
The rotor of the interior permanent magnet synchronous motor according to any one of claims 4 to 9, wherein the rotor is embedded. The average period in which the terminals of the armature winding are electrically interrupted is shortened when the temperature at a predetermined position of the embedded magnet synchronous motor is high.
The rotor of the interior permanent magnet synchronous motor according to claim 22.

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