JP6759893B2 - Rotating electric rotor - Google Patents

Description

The present invention relates to a rotary electric rotor including a rotor core and a magnet fixed to the rotor core while being inserted into a magnet hole of the rotor core.

Conventionally, in a rotary electric rotor, a so-called embedded magnet type rotor in which a magnet is fixed to the rotor core while being inserted into a magnet hole of the rotor core is known.

Patent Document 1 describes that in an embedded magnet type rotor, by forming a through hole on the inner peripheral side of a magnet hole in the rotor core, the weight of the rotor core can be reduced, and thereby the effect of reducing the centrifugal force of the rotor core can be obtained. Has been done.

Japanese Unexamined Patent Publication No. 2012-100424

In the embedded magnet type rotor described in Patent Document 1, at the time of manufacture, a resin material as a magnet fixing material is injected into the magnet hole with the magnet inserted in the magnet hole, heat-cured, and cooled to room temperature to cool the rotor core. The magnet may be fixed to the object. In such a configuration, the contact pressure between the rotor core and the magnet may increase due to the difference in the coefficient of thermal expansion between the rotor core and the magnet during manufacturing. In this case, the insulating effect between the magnet and the rotor core due to the insulating film of the magnet is reduced, so that an eddy current is likely to be generated in the magnet, and the eddy current may generate heat in the magnet to reduce the magnetic force. There is. As a result, the torque of the rotary electric machine formed by incorporating the rotor may decrease.

On the other hand, in the rotor core, it is conceivable to suppress an increase in the contact pressure between the rotor core and the magnet during manufacturing by forming a large through hole in the vicinity of the periphery of the magnet hole. However, when a large through hole is simply formed in the rotor core in this way, the magnetic flux generated from the magnet during use is hindered by the through hole, which may cause a decrease in the torque of the rotary electric machine formed by incorporating the rotor core.

An object of the rotary electric rotor of the present invention is to suppress a decrease in torque of a rotary electric machine configured by incorporating the rotor by suppressing the generation of an eddy current in a magnet.

The rotary electric rotor of the present invention is a rotary electric rotor including a rotor core and a plurality of magnets fixed to the rotor core by a magnet fixing material while being inserted into a plurality of magnet holes formed in the rotor core. The rotor core has a plurality of slits, and when each of the slits is formed in the vicinity of each periphery of the plurality of magnet holes, and the magnet fixing material is heat-cured and cooled to room temperature. The stress generated by the thermal expansion difference between the rotor core and the magnet includes a plurality of slits that are deformed so that the opposing inner surfaces of the slits come into contact with each other, and each of the plurality of slits is of the slit. A rotating electric machine formed so that at least a part of the slit is located within a mirrored range of the magnet with one long side of the magnet having a rectangular cross section arranged in the magnet hole in the vicinity as an axis. It is a rotor.

According to the rotary electric rotor of the present invention, when the magnet fixing material is heat-cured during the manufacture of the rotor and cooled to room temperature, the difference in thermal expansion between the magnet and the rotor core causes the inside of the slit near the periphery of the magnet. Deforms so that the sides come into contact . As a result, the contact pressure acting between the magnet and the rotor core can be reduced, so that the generation of eddy current in the magnet can be suppressed. Further, it is possible to prevent the magnetic flux emitted from the magnet from being obstructed by the slit due to the contact between the inner side surfaces of the slit. As a result, it is possible to suppress a decrease in torque of the rotary electric machine configured by incorporating the rotor.

FIG. 5 is a view of a part of the circumferential direction of the magnet fixing material before heat curing in the rotary electric rotor of the embodiment according to the present invention as viewed from one side in the axial direction. In the embodiment, it is a figure corresponding to FIG. 1, which shows a state in which a slit is deformed when the magnet fixing material is heat-cured and cooled to room temperature. Corresponding to FIG. 2, the rotary electric rotor of the comparative example shows a state after the magnet fixing material is heat-cured and cooled to room temperature in a configuration in which a through hole is formed at a position far away from the magnet. It is a figure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The shapes, materials, and numbers described below are examples for explanation and can be appropriately changed according to the specifications of the rotary electric rotor. In the following, the equivalent elements will be described with the same reference numerals in all the drawings. In addition, in the explanation in the text, the reference numerals described above shall be used as necessary.

FIG. 1 is a view of a part of the resin material 30 which is a magnet fixing material before heat curing in the rotary electric rotor 10 of the embodiment as viewed from one side in the axial direction. FIG. 2 is a diagram corresponding to FIG. 1 showing a state in which the slit 22 is deformed when the resin material 30 is heat-cured and cooled to room temperature in the embodiment. In the following, the rotary electric rotor 10 may be referred to as a rotor 10.

The rotor 10 is used to form a rotary electric machine (not shown). For example, a rotary electric motor is a permanent magnet type synchronous motor driven by a three-phase alternating current. For example, a rotary electric machine is used as a motor for driving a hybrid vehicle, as a generator, or as a motor generator having both functions.

The rotor 10 is a cylindrical member, and when in use, a rotating shaft (not shown) is inserted and fixed inside the rotor 10. The rotor 10 is arranged inside a case (not shown) during use. With the rotor 10 arranged inside the case, both ends of the rotating shaft are rotatably supported by bearings (not shown) with respect to the case. Inside the case, a cylindrical stator (not shown) is fixed to the outside of the rotor 10 in the radial direction. The stator includes a substantially tubular stator core and a stator coil wound around a plurality of teeth protruding from the inner peripheral surface of the stator core. A radial gap is formed between the outer peripheral surface of the rotor 10 and the inner peripheral surface of the stator. As a result, a rotary electric machine is formed. In the following description, the "radial direction" refers to the radial direction which is the radial direction of the rotor 10, and the "circumferential direction" refers to the direction along the circle centered on the central axis of the rotor 10. The "axial direction" refers to a direction along the central axis of the rotor 10.

As shown in FIG. 1, the rotor 10 includes a rotor core 12 and a magnet 14 which is a permanent magnet embedded at a plurality of positions in the circumferential direction of the rotor core 12. Specifically, the rotor core 12 is a laminated body formed by laminating a plurality of disk-shaped electromagnetic steel plates 16 which are magnetic materials. A shaft hole (not shown) is formed in the central portion of the rotor core 12, and a plurality of magnet holes 20 are formed around the shaft hole. A rotating shaft is fixed inside the shaft hole.

Further, slits 22 are formed inside each magnet hole 20 in the radial direction and in the vicinity of the periphery of each magnet hole 20. The slit 22 is formed in the vicinity of the inner side surface in the radial direction of the magnet hole 20 so as to be along the inner side surface in the radial direction of each magnet hole 20 and separated from the magnet hole 20 by a predetermined distance d. The slit 22 has a flat rectangular shape that is long in the direction along the radial inner surface 20a of the magnet hole 20 and short in the direction orthogonal to the radial inner surface 20a of the magnet hole 20 when viewed from one side in the axial direction. is there. The lateral dimension L1 of the slit 22 is smaller than the longitudinal dimension L2 of the slit 22 by, for example, 1/10 or less. The longitudinal dimension L2 of the slit 22 is larger than the circumferential dimension L3 (FIG. 2) along the slit 22 in the magnet 14 (L2> L3). Due to the presence of each slit 22, as will be described later, the contact pressure acting between the magnet 14 and the rotor core 12 due to the difference in thermal expansion between the magnet 14 and the rotor core 12 during the manufacture of the rotor 10 is reduced. , The generation of eddy current in the magnet 14 can be suppressed.

The magnet hole 20 has a substantially rectangular shape when viewed from one side in the axial direction. The plurality of magnet holes 20 are arranged at intervals along the circumferential direction of the rotor core 12.

The electrical steel sheet 16 has a disk shape, for example, a silicon electrical steel sheet. The electromagnetic steel plate 16 is formed by, for example, annularly punching a thin steel plate having a thickness of 0.5 mm or less. In the electrical steel sheet 16, the shaft hole at the center, a plurality of magnet holes 21 around the shaft hole, and a slit element 22a, which are a plurality of rectangular holes radially inside each magnet hole, are formed by punching the electromagnetic steel plate 16.

The shaft holes of the rotor core 12 are formed by connecting the shaft holes of the plurality of electromagnetic steel plates 16 in the axial direction. By connecting the plurality of magnet holes 21 of the plurality of electrical steel sheets 16 in the axial direction, the plurality of magnet holes 20 of the rotor core 12 are formed. The plurality of magnet holes 20 of the rotor core 12 are formed as a set of two, and the magnet holes 20 of each set are combined to form a V-shape that opens outward in the radial direction. A magnet 14 is inserted into each magnet hole 20. At this time, the magnet 14 is fixed to the rotor core 12 by the resin material 30, which is a magnet fixing material that is injected and solidified into the gaps at both ends in the circumferential direction of the magnet hole. In FIGS. 1 and 2, the resin material 30 is shown as sand.

Further, by connecting the plurality of slit elements 22a of the plurality of electromagnetic steel plates 16 in the axial direction, the plurality of slits 22 of the rotor core 12 are formed.

The magnet 14 has a rectangular parallelepiped shape that is long in the axial direction, and its magnetization direction is orthogonal to the outer peripheral side surface and the inner peripheral side surface. The surface of the magnet 14 is provided with an oxide film or an insulating film formed by a resin coating. This insulating film has a function of insulating between the magnet 14 and the rotor core 12 and suppressing the generation of eddy current in the magnet 14 during use. The magnet 14 is fixed in the magnet hole 20 by heating the resin material 30 injected into the magnet hole 20. At this time, the resin material 30 is heat-cured and then cooled to room temperature.

One magnetic pole 15 is formed by two magnets 14 adjacent to each other. The two magnets 14 forming one magnetic pole 15 are arranged so as to spread in a substantially V shape toward the outer peripheral side of the rotor core 12 according to the arrangement of the plurality of magnet holes 20. In addition, one magnetic pole may be formed by three or more magnets.

In the case of manufacturing the rotor 10, a plurality of electromagnetic steel plates 16 are laminated to form a laminated body, and the magnets 14 are inserted into the magnet holes 20 at both ends in the circumferential direction of the magnet holes 20. The resin material 30 is injected into the voids. Then, the resin material 30 is heat-cured by heating the laminate by a heating device (not shown), and then cooled to room temperature, so that each magnet 14 is fixed to the rotor core 12.

At this time, as shown in FIG. 1, in the state before heat curing of the resin material 30, the lateral dimension L1 of the slit 22 is relatively large, and a void is formed inside the slit 22. As a result, the magnetic flux emitted from the magnet 14 is greatly bent immediately before the slit 22, as shown by the arrow α in FIG. 1, and the slit 22 hinders the magnetic flux.

On the other hand, as shown in FIG. 2, after the resin material 30 is heat-cured and cooled to room temperature, the magnet 14 and the rotor core 12 are radially rotated based on the difference in thermal expansion between the magnet 14 and the rotor core 12. A large stress tends to be generated in the rotor core 12 so as to strongly press each other. For example, the rotor core 12 expands by heating and contracts by cooling, but the magnet 14 may contract by heating and expand by cooling depending on the type of magnet. As a result, the contact pressure between the rotor core 12 and the magnet 14 may tend to increase after cooling due to the above thermal expansion difference. In this case, in the embodiment, the slit 22 is deformed so that the inner side surfaces facing each other in the lateral direction are close to each other or come into contact with each other so that the slit 22 absorbs the stress in the radial direction of the rotor core 12.

According to the rotor 10, when the resin material 30 is heat-cured at the time of manufacturing the rotor 10 and cooled to room temperature, the slit 22 around the magnet 14 due to the difference in thermal expansion between the magnet 14 and the rotor core 12. The radial inner surface of the magnet is deformed so as to be close to or in contact with each other. As a result, the contact pressure acting between the magnet 14 and the rotor core 12 can be reduced, so that the insulating effect between the magnet 14 and the rotor core 12 due to the insulating film of the magnet 14 can be prevented from being lowered. Therefore, the generation of eddy current in the magnet 14 can be suppressed. Further, when the inner side surfaces of the slit 22 come close to each other or come into contact with each other, the magnetic flux passes across the slit 22 as shown by the arrow β in FIG. 2, so that the magnetic flux is immediately before the slit 22 unlike the state of FIG. It will not be bent significantly. As a result, it is possible to prevent the magnetic flux emitted from the magnet 14 from being obstructed by the slit 22. As a result, it is possible to suppress a decrease in torque of the rotary electric machine configured by incorporating the rotor 10.

Further, since the longitudinal dimension L2 of the slit 22 is larger than the circumferential dimension L3 (FIG. 2) along the slit 22 in the magnet 14, the magnet 14 and the rotor core 12 are formed even after the resin material 30 is heat-cured and cooled to room temperature. The contact pressure acting between them can be made sufficiently small.

FIG. 3 shows a state after the magnet fixing material is heat-cured and cooled to room temperature in the rotary electric rotor 10 of the comparative example in a configuration in which the through hole 34 is formed at a position far away from the magnet 14. It is a figure corresponding to FIG. In the comparative example shown in FIG. 3, in the configuration of the embodiment shown in FIGS. 1 and 2, a wide through hole 34 is formed at a position largely separated in the radial direction of each magnet hole 20. The through hole 34 has a rectangular shape when viewed from one side in the axial direction. For example, the lateral dimension L1a of the through hole 34 is smaller than the longitudinal dimension L2a, for example, at a ratio of about 1/3. Further, when the resin material 30 which is a magnet fixing material is heat-cured and cooled to room temperature with the magnet 14 inserted in the magnet hole 20, the through hole 34 is hardly deformed, and the facing inner surface surface is Neither close nor contact.

In such a comparative example, the resin material 30 is heat-cured and cooled to room temperature with the magnet 14 inserted in the magnet hole 20 at the time of manufacturing the rotor 10. At this time, due to the difference in thermal expansion between the magnet 14 and the rotor core 12, a large stress is generated from the rotor core 12 to the magnet 14 so as to compress the magnet 14 in the radial direction, as shown by an arrow α in FIG. In this case, the contact pressure between the rotor core 12 and the magnet 14 may increase significantly. In this case, the insulating effect of the insulating film of the magnet 14 between the magnet 14 and the rotor core 12 is reduced, so that an eddy current is likely to be generated in the magnet 14, and the eddy current generates heat in the magnet 14 to generate magnetic force. Is likely to decrease. As a result, the torque of the rotary electric machine formed by incorporating the rotor 10 may decrease. In the embodiment described above, such inconvenience can be prevented.

In the above embodiment, the case where the rotor core 12 is composed of a laminated body in which a plurality of electromagnetic steel plates 16 are laminated is described, but the rotor core is not limited to the laminated body. For example, the rotor core may be formed by pressure molding a resin binder and a magnetic material powder.

Further, in the configurations of FIGS. 1 and 2, the case where the two magnets 14 are arranged in a V shape has been described, but in the rotor 10, each magnet 14 is arranged along the circumferential direction and is located near the periphery of the magnet hole. The structure may be such that a slit is formed. Further, although the case where the magnet fixing material is a resin material has been described above, various materials can be used as long as they are cured by heating.

10 rotary electric rotor (rotor), 12 rotor core, 14 magnets, 15 magnetic poles 16 electromagnetic steel sheets, 20 magnet holes, 20a radial inner surface, 21 magnet holes, 22 slits, 22a slit elements, 30 resin materials, 34 through holes.

Claims (1)

A rotary electric rotor including a rotor core and a plurality of magnets fixed to the rotor core by a magnet fixing material while being inserted into a plurality of magnet holes formed in the rotor core.
The rotor core has a plurality of slits, each of which is formed in the vicinity of each periphery of the plurality of magnet holes, and when the magnet fixing material is heat-cured and cooled to room temperature. It includes a plurality of slits that are deformed so that the opposing inner surfaces of the slits come into contact with each other due to the stress generated by the thermal expansion difference between the rotor core and the magnet.
Each of the plurality of slits has at least a part of the slit within a range in which the magnet is reflected with one long side of the magnet having a rectangular cross section arranged in the magnet hole in the vicinity of the slit as an axis. Is formed to be located,
Rotating electric rotor.

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