WO2022044090A1

WO2022044090A1 - Rotor

Info

Publication number: WO2022044090A1
Application number: PCT/JP2020/031898
Authority: WO
Inventors: 秀範内田; 秀樹久田
Original assignee: 株式会社東芝; 東芝インフラシステムズ株式会社
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2022-03-03
Also published as: JPWO2022044090A1

Abstract

A rotor according to the present embodiment comprises: a rotor core; first and second permanent magnets; and a shaft press-fitted into the rotor core. The rotor core has an inner circumferential part, an outer circumferential part, and a first rib for connecting the inner circumferential part and the outer circumferential part. The outer circumferential part has a first hole through which the first permanent magnet is inserted, a second hole through which the second permanent magnet is inserted, a first core portion, a second core portion, and a bridge for connecting the first and second core portions between the first hole and the second hole. An outer circumferential surface has a first notch connected to the first hole, and a second notch connected to the second hole. The first rib is connected to the outer circumferential part in a region between a first straight line that passes through a corner far from a d axis among corners opposite to the d axis of the first permanent magnet and that is parallel to the d axis and a second straight line that passes through a corner far from a d axis among corners opposite to the d axis of the second permanent magnet and that is parallel to the d axis.

Description

Rotor

An embodiment of the present invention relates to a rotor.

A rotary electric machine is known which includes a cylindrical stator and a rotor rotatably supported inside the stator, and rotates the rotor by a rotating magnetic field generated by the stator. Further, with respect to a rotary electric machine, a technique of forming a hole or the like in a rotor core is also known in order to reduce the weight of the rotor.
By the way, when the shaft is press-fitted into the rotor core, a force that pushes the permanent magnet embedded in the rotor core outward in the radial direction acts on the rotor core, which may cause deformation of the rotor core.

Japanese Unexamined Patent Publication No. 2009-303446 Japanese Unexamined Patent Publication No. 2012-75208 Japanese Unexamined Patent Publication No. 2013-208014 Japanese Unexamined Patent Publication No. 2016-323340

An object of the present embodiment is to provide a rotor capable of suppressing deformation of the rotor core.

The rotor of this embodiment is
A substantially cylindrical rotor core, a first permanent magnet and a second permanent magnet forming magnetic poles in the rotor core, and a shaft press-fitted into the rotor core are provided, and the rotor core includes an inner peripheral portion surrounding the shaft. The outer peripheral portion comprises an outer peripheral portion that surrounds the inner peripheral portion with a gap interposed therebetween, and a plurality of first ribs that are inclined in the radial direction and connect the inner peripheral portion and the outer peripheral portion. A first hole surrounded by a first hole into which the first permanent magnet is inserted, a second hole into which the second permanent magnet is inserted, an outer peripheral surface of the rotor core, the first hole, and the second hole. The core portion, the second core portion located between the first hole and the second hole and the gap, and the first core portion and the second core portion between the first hole and the second hole. It has a bridge connecting the core portion, and the outer peripheral surface has a first notch communicating with the first hole and a second notch communicating with the second hole, and the plurality of first holes are provided. Assuming that the axis passing through the central axis of the shaft and the center in the circumferential direction of the magnetic pole is the d-axis, one of the one ribs is the d-axis of the angles facing the d-axis of the first permanent magnet. A first straight line that passes through an angle far from the d-axis and is parallel to the d-axis, and a second straight line that passes through an angle far from the d-axis and is parallel to the d-axis of the angles facing the d-axis of the second permanent magnet. In the area between and, it is connected to the outer peripheral portion.

FIG. 1 is a cross-sectional view of the rotary electric machine 1 of the present embodiment. FIG. 2 is a cross-sectional view of the rotary electric machine 1 shown in FIG. 1 along the line AB of the rotor 3. FIG. 3 is an enlarged cross-sectional view showing the rotor core 32 for one magnetic pole of the rotor 3 shown in FIG. 2. FIG. 4 is a cross-sectional view taken along the line AB of the rotor 3 of the modified example of the rotary electric machine 1 shown in FIG. FIG. 5 is an enlarged cross-sectional view showing the rotor core 32 for one magnetic pole of the rotor 3 shown in FIG.

Hereinafter, this embodiment will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate changes while maintaining the gist of the invention, which are naturally included in the scope of the present invention. Further, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is merely an example, and the present invention is used. It does not limit the interpretation. Further, in the present specification and each figure, the same reference reference numerals may be given to the components exhibiting the same or similar functions as those described above with respect to the above-mentioned figures, and the overlapping detailed description may be omitted as appropriate. ..

FIG. 1 is a cross-sectional view of the rotary electric machine 1 of the present embodiment.
The rotary electric machine 1 of the present embodiment is configured as an embedded permanent magnet type (IPM: Interior Permanent Magnet) rotary electric machine, and is suitably applied to a drive motor or a generator in, for example, a hybrid electric vehicle (HEV) or an electric vehicle (EV). Will be done. The rotary electric machine 1 includes a substantially cylindrical stator 2, a substantially cylindrical rotor 3 in which a permanent magnet is embedded, a housing 10 for accommodating the stator 2 and the rotor 3, and a cover 11 fixed to the housing 10. I have.

The stator 2 includes a cylindrical stator core 21 and a winding 22 mounted on the stator core 21. The stator core 21 is configured as a laminated body in which a large number of magnetic materials, for example, annular electromagnetic steel sheets, are laminated concentrically. The housing 10 has a substantially cylindrical inner peripheral surface 10A. The stator core 21 is fixed to the inner peripheral surface 10A. The structure of the stator 2 is not particularly limited, and a general structure can be widely adopted.

The rotor 3 is located inside the stator 2 and is arranged with a slight gap (air gap) between the rotor 3 and the stator 2. The rotor 3 includes a shaft 31, a substantially cylindrical rotor core 32, and a permanent magnet (not shown in FIG. 1). The shaft 31 and the rotor core 32 are configured to be rotatable about the central axis C.

Bearings

41 and 42 are attached to the shaft 31. The

bearings

41 and 42 are fixed by the housing 10 and the cover 11. The shaft 31 is rotatably supported by the housing 10 and the cover 11 around the central axis C via

bearings

41 and 42. The illustrated example simply shows an example of a bearing structure that supports the shaft 31, and a detailed description of the structure will be omitted.

The rotor core 32 is configured as a laminated body in which a large number of magnetic materials, for example, a large number of annular electromagnetic steel plates such as silicon steel are laminated concentrically. The outer peripheral surface 32S of the rotor core 32 faces the inner peripheral surface 2S of the stator 2 with a slight gap. The rotor core 32 has a hole 32H formed coaxially with the central axis C at the center thereof. The hole 32H penetrates the rotor core 32 in the axial direction. The shaft 31 is press-fitted into the hole 32H and extends coaxially with the rotor core 32.

In the present specification, the axial direction corresponds to the direction in which the shaft 31 or the central axis C shown in FIG. 1 extends. Further, the radial direction described later corresponds to a direction in which a straight line connecting the central axis C and the outer peripheral surface 32S of the rotor core 32 extends in a cross section orthogonal to the central axis C, and the circumferential direction corresponds to a rotor in the cross section. It corresponds to the direction along the circumference of 3.

FIG. 2 is a cross-sectional view of the rotary electric machine 1 shown in FIG. 1 along the line AB of the rotor 3.
In this embodiment, the rotor 3 has a plurality of magnetic poles, for example, eight magnetic poles. In the rotor core 32, the axis extending in the radial direction of the rotor core 32 through the boundary between the magnetic poles adjacent to each other in the circumferential direction and the central axis C is called the q-axis, and the axis electrically separated by 90 ° in the circumferential direction from the q-axis. That is, the axis passing through the center of one magnetic pole in the circumferential direction and the central axis C is referred to as the d-axis. Here, the direction in which the interlinkage magnetic flux formed by the stator is likely to flow is referred to as the q-axis. The d-axis and the q-axis are provided alternately in the circumferential direction of the rotor core 32 and in a predetermined phase. One magnetic pole portion of the rotor core 32 means a region between two q-axis adjacent to each other in the circumferential direction (a circumferential angle region of 1/8 circumference).

The rotor 3 includes a shaft 31, a rotor core 32, and a plurality of permanent magnets M. A plurality of permanent magnets M, for example, two permanent magnets M, are inserted in the rotor core 32 for each magnetic pole. At each magnetic pole, the two permanent magnets M are arranged line-symmetrically with respect to the d-axis. These permanent magnets M are fixed to the rotor core 32 with, for example, an adhesive.

The permanent magnet M is formed, for example, in the shape of an elongated flat plate having a rectangular cross section, and has a length substantially equal to the axial length of the rotor core 32. That is, each permanent magnet M is embedded over almost the entire length of the rotor core 32. The permanent magnet M may be configured by combining magnets divided into a plurality of magnets in the axial direction. Each permanent magnet M has a pair of long sides and a pair of short sides in the cross section. The shape of the cross section of the permanent magnet M is not limited to a rectangular shape (rectangular shape), and may be a parallelogram. Each permanent magnet M is magnetized in a direction perpendicular to the long side. The two permanent magnets M located on both sides of the d-axis in the circumferential direction, that is, the two permanent magnets M constituting one magnetic pole are arranged so that the magnetization directions are the same. Further, the two permanent magnets M located on both sides of the q-axis in the circumferential direction are arranged so that the magnetization directions are opposite to each other.

The rotor core 32 includes an inner peripheral portion 321 that surrounds the shaft 31, an outer peripheral portion 322 that surrounds the inner peripheral portion 321 with the gap 32C interposed therebetween, and a plurality of first ribs R1 that connect the inner peripheral portion 321 and the outer peripheral portion 322. have. The gap 32C penetrates the rotor core 32 in the axial direction. The void 32C is partitioned by the first rib R1. In the example shown in FIG. 2, one first rib R1 is provided for each magnetic pole. That is, the rotor core 32 has eight first ribs R1.

The inner peripheral portion 321 corresponds to the portion of the rotor core 32 between the shaft 31 and the gap 32C, and is formed in an annular shape surrounding the shaft 31. The outer peripheral portion 322 corresponds to a portion of the rotor core 32 between the gap 32C and the outer peripheral surface 32S, and is formed in an annular shape surrounding the inner peripheral portion 321. That is, the outer peripheral portion 322 is located outside the inner peripheral portion 321 in the radial direction and is separated from the inner peripheral portion 321. The outer edge E1 of the inner peripheral portion 321 faces the inner edge E2 of the outer peripheral portion 322 with the gap 32C interposed therebetween.

Each of the first ribs R1 is connected to the outer edge E1 of the inner peripheral portion 321 and the inner edge E2 of the outer peripheral portion 322, respectively. The first rib R1 corresponds to a portion of the rotor core 32 between the gaps 32C adjacent in the circumferential direction. The first rib R1 is formed in a linear shape inclined with respect to the radial direction. Further, the first rib R1 is inclined with respect to the d-axis and the q-axis. The extending direction of the first rib R1 is, for example, substantially parallel to the tangential direction of the outer edge E1. For all the first ribs R1, the direction from the connection position between the first rib R1 and the outer peripheral portion 322 to the connection position between the first rib R1 and the inner peripheral portion 321 is right with respect to the central axis C in the cross section. It is a rotation and coincides with the rotation direction A of the rotor 3.

The outer peripheral portion 322 has a plurality of holes H. The plurality of holes H each penetrate the rotor core 32 in the axial direction. The permanent magnet M is inserted in the hole H. Such a hole H may be referred to as a magnet holding hole, a magnet insertion hole, or the like. Focusing on one magnetic pole, the holes H are formed on both sides in the circumferential direction with the d-axis in between. These two holes H are arranged so that the distance in the circumferential direction gradually increases from the central axis C toward the outer peripheral surface 32S of the rotor core 32 in the cross section.

Further, the outer peripheral portion 322 has a plurality of holes 323. The plurality of holes 323 each penetrate the rotor core 32 in the axial direction. The plurality of holes 323 are arranged in the circumferential direction at equal intervals. Each of the holes 323 is formed on the q-axis. That is, the holes 323 are formed between the holes H provided in the magnetic poles adjacent to each other in the circumferential direction.

FIG. 3 is an enlarged cross-sectional view showing the rotor core 32 for one magnetic pole of the rotor 3 shown in FIG. 2.
In the example shown in FIG. 3, the permanent magnet located on the left side across the d-axis is shown as the first permanent magnet M1, the hole is shown as the first hole H1, and the permanent magnet located on the right side across the d-axis is the first. The two permanent magnets M2 are used, and the holes are shown as the second holes H2. The first permanent magnet M1 is inserted into the first hole H1. The second permanent magnet M2 is inserted into the second hole H2. Each of the first permanent magnet M1 and the second permanent magnet M2 has a short side facing the d-axis, and the distance between the d-axis and the short side gradually increases from the outer circumference to the inner circumference of the rotor core 32. It is arranged like this.

In the rotor core 32, the outer peripheral portion 322 is a fan-shaped first core portion C1 surrounded by the outer peripheral surface 32S of the rotor core 32 and the first hole H1 and the second hole H2 in addition to the first hole H1 and the second hole H2. A second core portion C2 located between the first hole H1 and the second hole H2 and the gap 32C, and a first core portion C1 and a second core portion between the first hole H1 and the second hole H2. It has a bridge BR that connects to C2.

The first hole H1 has a rectangular magnet holding region H11 corresponding to the cross-sectional shape of the first permanent magnet M1, a void region H12 extending from the magnet holding region H11 toward the bridge BR, and an outer periphery from the magnet holding region H11. It has a void region H13 extending toward the surface 32S. The second core portion C2 has a pair of holding protrusions C22 and C23 protruding from the edge C21 in contact with the long side of the first permanent magnet M1 at both ends in the longitudinal direction of the magnet holding region H11 toward the first core portion C1. There is. The holding protrusion C22 faces the gap region H12, and the holding protrusion C23 faces the gap region H13. The first core portion C1 has a holding projection C13 protruding from the edge C11 in contact with the long side of the first permanent magnet M1 toward the second core portion C2. The holding protrusion C13 faces the holding protrusion C23. The magnet holding region H11 is formed between the edge C11 and the edge C21. The edges C11 and C21 are substantially parallel to each other and are inclined with respect to the d-axis, respectively. The void regions H12 and H13 in the first hole H1 function as a flux barrier that suppresses magnetic flux leakage from both ends of the first permanent magnet M1 in the longitudinal direction to the rotor core 32, and also contributes to weight reduction of the rotor core 32.

The second hole H2 has a rectangular magnet holding region H21 corresponding to the cross-sectional shape of the second permanent magnet M2, a void region H22 extending from the magnet holding region H21 toward the bridge BR, and an outer periphery from the magnet holding region H21. It has a void region H23 extending toward the surface 32S. The second core portion C2 has a pair of holding protrusions C25 and C26 protruding from the edge C24 in contact with the long side of the second permanent magnet M2 at both ends in the longitudinal direction of the magnet holding region H21 toward the first core portion C1. There is. The holding protrusion C25 faces the gap region H22, and the holding protrusion C26 faces the gap region H23. The first core portion C1 has a holding projection C16 protruding from the edge C14 in contact with the long side of the second permanent magnet M2 toward the second core portion C2. The holding protrusion C16 faces the holding protrusion C26. The magnet holding region H21 is formed between the edge C14 and the edge C24. The edges C14 and C24 are substantially parallel to each other and are inclined with respect to the d-axis, respectively. The void regions H22 and H23 in the second hole H2 function as a flux barrier that suppresses magnetic flux leakage from both ends of the second permanent magnet M2 in the longitudinal direction to the rotor core 32, and also contributes to weight reduction of the rotor core 32.

The bridge BR is located between the void region H12 of the first hole H1 and the void region H22 of the second hole H2. The bridge BR extends in the radial direction, and extends substantially parallel to the d-axis at a position overlapping the d-axis. In the example shown in FIG. 3, there is only one bridge BR.

The outer peripheral surface 32S has a first notch N1 communicating with the first hole H1 and a second notch N2 communicating with the second hole H2. That is, each of the first hole H1 and the second hole H2 extends toward the outer peripheral surface 32S and is open or open to the outer periphery of the rotor core 32. In short, in the rotor core 32, no bridge is formed between the outer peripheral surface 32S and the first hole H1 and between the outer peripheral surface 32S and the second hole H2. These first notch N1 and second notch N2 each penetrate the rotor core 32 in the axial direction. Since such a first notch N1 and a second notch N2 are formed, magnetic flux leakage is suppressed. On the other hand, by forming the first notch N1 and the second notch N2, the first core portion C1 is connected to the second core portion C2 by one bridge BR. Therefore, a bridge is provided between the outer peripheral surface 32S and the first hole H1 and between the outer peripheral surface 32S and the second hole H2 (a configuration in which the first notch and the second notch are not formed). In the configuration of the present embodiment, the support strength of the first core portion C1 is low, and stress tends to concentrate on the bridge BR.

One first rib R1 is a first straight line LN1 passing through an angle MC1 far from the d-axis and parallel to the d-axis among the angles MC1 and MC2 facing the d-axis of the first permanent magnet M1, and the second permanent magnet M2. A region of the angle MC3 and MC4 facing the d-axis, which passes through the angle MC3 far from the d-axis and is parallel to the d-axis, and is connected to the outer peripheral portion 322. Further, the first rib R1 is connected to the outer peripheral portion 322 on the extension line of the bridge BR. In the example shown in FIG. 3, the connection position between the first rib R1 and the outer peripheral portion 322 is located on the d-axis. The first straight line LN1 may pass through the angle MC2, and the second straight line LN2 may pass through the angle MC4. Further, the first straight line LN1 may pass through the holding protrusion C22, and the second straight line LN2 may pass through the holding protrusion C25.

When the shaft 31 is press-fitted into the rotor core 32, a force acting from the first rib R1 toward the outer circumference along the radial direction acts on the outer peripheral portion 322. Since the connection position between the first rib R1 and the outer peripheral portion 322 is located in the above range region, a force acts from the first rib R1 toward the outer circumference along the bridge BR, and the inclination of the first core portion C1 Can be suppressed. Therefore, the deformation of the rotor core 32 is suppressed.

Further, a hole 323 penetrating the rotor core 32 is formed on the q-axis. The weight of the rotor core 32 is reduced. It is desirable that the shape and size of the hole 323 are set so as not to obstruct the passage of the magnetic flux for producing the reluctance torque.

Next, a modified example will be described.

FIG. 4 is a cross-sectional view taken along the line AB of the rotor 3 of the modified example of the rotary electric machine 1 shown in FIG.
In the modified example shown in FIG. 4, the rotor core 32 has a plurality of second ribs R2 connecting the inner peripheral portion 321 and the outer peripheral portion 322 in addition to the first rib R1 as compared with the example shown in FIG. It differs in that. The first rib R1 and the second rib R2 are alternately arranged in the circumferential direction between the inner peripheral portion 321 and the outer peripheral portion 322. The first rib R1 and the second rib R2 extend in different directions from each other. The extension direction of the first rib R1 is as described with reference to FIG. For all the second ribs R2, the direction from the connection position between the second rib R2 and the outer peripheral portion 322 to the connection position between the second rib R2 and the inner peripheral portion 321 is left with respect to the central axis C in the cross section. It is a rotation and is in the direction opposite to the rotation direction A of the rotor 3.

The connection position between the first rib R1 and the outer peripheral portion 322 is almost the same as the connection position between the second rib R2 and the outer peripheral portion 322. The connection position between the first rib R1 and the inner peripheral portion 321 is separated from the connection position between the second rib R2 and the inner peripheral portion 321 in the circumferential direction. The gap 32C surrounded by the first rib R1, the second rib R2, and the inner peripheral portion 321 intersects the d-axis and is formed in a substantially triangular shape with the inner peripheral side as the base and the outer peripheral side as the apex in the cross section. Has been done. The gap 32C surrounded by the first rib R1, the second rib R2, and the outer peripheral portion 322 intersects the q-axis and has a substantially fan shape that spreads in the circumferential direction from the inner peripheral side to the outer peripheral side in the cross section. It is formed.

FIG. 5 is an enlarged cross-sectional view showing the rotor core 32 for one magnetic pole of the rotor 3 shown in FIG.
The first rib R1 and the second rib R2 are connected to the outer peripheral portion 322 in the region between the first straight line LN1 and the second straight line LN2. The first straight line LN1 is a line that passes through the angle MC1 of the first permanent magnet M1 and is parallel to the d-axis, and the second straight line LN2 is a line that passes through the angle MC3 of the second permanent magnet M2 and is parallel to the d-axis. be. Further, the first rib R1 and the second rib R2 are arranged line-symmetrically with respect to the d-axis (or an extension of the bridge BR). Even in such a modified example, the same effect as described above can be obtained.

As described above, according to the present embodiment, it is possible to provide a rotor capable of suppressing deformation of the rotor core.

It should be noted that the present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, some components may be removed from all the components shown in the embodiments. In addition, components across different embodiments may be combined as appropriate.
For example, the number of magnetic poles, dimensions, shape, etc. of the rotor 3 are not limited to the above-described embodiment, and can be variously changed according to the design. The number of permanent magnets M installed at each magnetic pole of the rotor 3 is not limited to two, and can be increased as needed.

1 ... Rotating electric machine 2 ... Stator 3 ... Rotor C ... Central shaft 31 ... Shaft 32 ... Rotor core 32C ... Air gap 32S ... Outer peripheral surface R1 ... First rib R2 ... Second rib BR ... Bridge 321 ... Inner peripheral part 322 ... Outer peripheral part 323 ... Through hole C1 ... 1st core part C2 ... 2nd core part H1 ... 1st hole H2 ... 2nd hole M1 ... 1st permanent magnet M2 ... 2nd permanent magnet N1 ... 1st notch N2 ... 2nd notch

Claims

A substantially cylindrical rotor core, a first permanent magnet and a second permanent magnet forming magnetic poles in the rotor core, and a shaft press-fitted into the rotor core are provided.
The rotor core has an inner peripheral portion that surrounds the shaft, an outer peripheral portion that surrounds the inner peripheral portion with a gap in between, and a plurality of positions that are inclined in the radial direction and connect the inner peripheral portion and the outer peripheral portion. With 1 rib,
The outer peripheral portion includes a first hole into which the first permanent magnet is inserted, a second hole into which the second permanent magnet is inserted, an outer peripheral surface of the rotor core, the first hole, and the second hole. The first core portion surrounded by the first core portion, the second core portion located between the first hole and the second hole and the void, and the first core portion between the first hole and the second hole. It has a bridge that connects the portion and the second core portion, and has.
The outer peripheral surface has a first notch communicating with the first hole and a second notch communicating with the second hole.
One of the plurality of first ribs has an angle of an angle facing the d-axis of the first permanent magnet, where the axis passing through the central axis of the shaft and the center in the circumferential direction of the magnetic pole is the d-axis. Of the first straight line passing through the angle far from the d-axis and parallel to the d-axis, and the angle of the second permanent magnet facing the d-axis, passing through the angle far from the d-axis and parallel to the d-axis. A rotor connected to the outer peripheral portion in the region between the second straight line and the outer peripheral portion.
The rotor according to claim 1, wherein the first rib is connected to the outer peripheral portion on an extension line of the bridge.
The rotor core further has a plurality of second ribs connecting the inner peripheral portion and the outer peripheral portion.
One of the plurality of second ribs is connected to the outer peripheral portion in the region between the first straight line and the second straight line.
The rotor according to claim 1 or 2, wherein the first rib and the second rib extend in different directions from each other and are arranged line-symmetrically with respect to the d-axis.
The outer peripheral portion further has a third hole adjacent to the second hole in the circumferential direction, and a through hole formed between the second hole and the third hole. The rotor according to any one of 1 to 3.