WO2019038958A1 - Rotary electric machine - Google Patents

Abstract

This rotary electric machine is provided with a stator (12) and a rotor (14). The rotor comprises a rotor iron core (24) and multiple permanent magnets (26) embedded in the rotor iron core and forming multiple magnetic poles. The rotor iron core comprises two embedding holes (34) which are provided on both sides of each magnetic pole center axis (d) and in which the permanent magnets are loaded, and multiple air gaps (30) which are provided between adjacent magnetic pole center axes and which face the embedding holes at an interval. Defining W1 as the interval between the outer periphery-side air gap (34c) of an embedding hole and the outer periphery-side air gap (34c) of the adjacent magnetic pole, W2 as the interval between the air gap and the loading region of the embedding hole, W3 as the interval between the air gap and the inner periphery-side air gap (34b) of the embedding hole, and W4 as the interval between the inner hole of the rotor iron core and the inner periphery-side air gap (34b), the rotor iron core is formed such that W1 ≤ W2, W1 ≤ W3 and W1 ≤ W4.<u> <b/> </u> <u> <b/> </u>

Description

Electric rotating machine

Embodiments of the present invention relate to a rotating electrical machine in which permanent magnets are provided on a rotor.

In recent years, high magnetic energy product permanent magnets have been developed through remarkable research and development of permanent magnets. A permanent magnet type rotary electric machine using such a permanent magnet is being applied as a motor or a generator of a train or a car. In general, a permanent magnet type rotary electric machine includes a cylindrical stator and a cylindrical rotor rotatably supported inside the stator. The rotor comprises a rotor core and a plurality of permanent magnets embedded in the rotor core.

A permanent magnet type rotary electric machine has been proposed that forms a magnetic circuit that can use reluctance torque in addition to magnet torque by arranging permanent magnets in the rotor so as to form a V shape that opens toward the outer peripheral surface side. ing.

JP, 2014-75882, A Unexamined-Japanese-Patent No. 2010-80799

In a rotating electrical machine used as a drive source of a moving body, a mounting space is small, and it is required to achieve high torque and high output in a limited space. Furthermore, it is desirable to be lighter if the torque is the same.

The present invention has been made in view of the above points, and its object is to provide a permanent magnet type rotary electric machine capable of reducing its weight while maintaining torque characteristics.

According to an embodiment, the rotating electrical machine includes a stator having a stator core and an armature winding, a shaft rotatable around a central axis, and a plurality of the shaft coaxially fixed to the shaft and arranged in the circumferential direction. And a rotor having a plurality of permanent magnets embedded in the rotor core and disposed for each of the magnetic poles. The rotor core has an inner hole coaxially formed with the central axis and into which the shaft is fitted, and a plurality of magnetic pole central axes extending radially with respect to the central axis and passing through the centers of the magnetic poles. It is provided on two sides of the magnetic pole central axis in the circumferential direction of the rotor core, and is provided between two embedded holes respectively loaded with the permanent magnets and the adjacent magnetic poles and spaced apart from each other. And a plurality of void holes facing the holes. Each of the embedded holes has an inner circumferential space and an outer circumferential surface extending to the inner circumferential side and the outer circumferential side of the permanent magnet in the loading region in which the permanent magnet is loaded and in the direction orthogonal to the magnetization direction of the permanent magnet. And the inner peripheral side gaps of the two embedded holes are located opposite to each other with the magnetic pole central axis interposed therebetween, and the outer peripheral side gaps of the two embedded holes are separated from the magnetic pole central axis And located adjacent to and adjacent to the outer circumferential air gap of the embedded hole of the adjacent magnetic pole. The gap between the outer periphery of the buried hole and the outer gap of the buried hole of the adjacent magnetic pole is W1, the gap between the gap and the loading region of the buried hole is W2, the inner periphery of the gap and the buried hole Assuming that the distance from the air gap is W3 and the distance between the inner hole of the rotor core and the inner air gap of the embedded hole is W4, the rotor core is W1 ≦ W2, W1 ≦ W3, W1 ≦ W4. Is formed.

FIG. 1 is a cross-sectional view showing a permanent magnet type rotary electric machine according to an embodiment. FIG. 2 is an enlarged cross-sectional view of a part of a rotor of the permanent magnet type rotating electric machine. FIG. 3 is a perspective view showing a rotor core and a permanent magnet of the rotary electric machine. FIG. 4 is an enlarged cross-sectional view of a part of a rotor of a permanent magnet type rotary electric machine according to a modification;

Hereinafter, various embodiments will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. In addition, each drawing is a schematic view for promoting the embodiment and the understanding thereof, and there are places where the shape, size, ratio, etc. are different from those of the actual device, but referring to the following description and known techniques. The design can be changed as appropriate.

FIG. 1 is a cross-sectional view of a permanent magnet type rotary electric machine according to an embodiment, FIG. 2 is a cross-sectional view showing a part of the rotor in an enlarged manner, and FIG. 3 is a perspective view showing the rotor.
As shown in FIG. 1, the rotary electric machine 10 is, for example, an inner rotor type rotary electric machine, and has an annular or cylindrical stator 12 supported by a fixed frame (not shown), and a central axis C inside the stator. And a rotor 14 rotatably supported coaxially with the stator 12. The rotary electric machine 10 is suitably applied to, for example, a drive motor or a generator in a hybrid vehicle (HEV) or an electric vehicle (EV).

The stator 12 includes a cylindrical stator core 16 and an armature winding 18 wound around the stator core 16. The stator core 16 is configured by laminating a large number of annular magnetic steel plates such as a magnetic material such as silicon steel in a concentric manner. A plurality of slots 20 are formed in the inner peripheral portion of the stator core 16. The plurality of slots 20 are arranged at equal intervals in the circumferential direction. Each slot 20 opens in the inner circumferential surface of the stator core 16 and extends radially from the inner circumferential surface. Each slot 20 extends over the entire axial length of the stator core 16. By forming the plurality of slots 20, the inner peripheral portion of the stator core 16 constitutes a plurality of (for example, 48 in the present embodiment) stator teeth 21 facing the rotor 14. An armature winding 18 is embedded in the plurality of slots 20 and wound around each stator tooth 21. By passing a current through the armature winding 18, a predetermined flux linkage is formed on the stator 12 (the stator teeth 21).

As shown in FIG. 1 and FIG. 3, the rotor 14 is fixed to a cylindrical shaft (rotary shaft) 22 rotatably supported at its both ends by bearings (not shown) and substantially at the axial center of the shaft 22 A cylindrical rotor core 24 and a plurality of permanent magnets 26 embedded in the rotor core 24 are provided. The rotor 14 is coaxially disposed inside the stator 12 with a slight gap. That is, the outer peripheral surface of the rotor 14 faces the inner peripheral surface of the stator 12 with a slight gap. The rotor core 24 has an inner hole 25 formed coaxially with the central axis C. The shaft 22 is inserted and fitted in the bore 25 and extends coaxially with the rotor core 24. The rotor core 24 is configured as a laminated body in which a large number of magnetic materials, for example, annular electromagnetic steel plates 24 a such as silicon steel, are concentrically stacked.

In the present embodiment, the rotor 14 is set to a plurality of magnetic poles, for example, eight poles. In the rotor core 24, an axis extending radially and radially through the center of each magnetic pole relative to the central axis C is electrically and magnetically 90 ° with respect to the d axis (magnetic pole central axis) and the d axis. The spaced apart axes are referred to as the q-axis. Here, the direction in which the flux linkage formed by the stator 12 easily flows 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 24 and in a predetermined phase. The one magnetic pole portion of the rotor core 24 refers to a region between q axes (a circumferential angle region of 1⁄8 circumference). For this reason, the rotor core 24 is configured to have eight poles (magnetic poles). The circumferential center of one magnetic pole is the d axis.

As shown in FIGS. 1 and 2, two permanent magnets 26 are embedded in the rotor core 24 for each magnetic pole. In the circumferential direction of rotor core 24, magnet embedded holes (hereinafter referred to as embedded holes) 34 having a shape corresponding to the shape of permanent magnet 26 are formed on both sides of each d axis, and a line Is located in Permanent magnets 26 are respectively disposed in the embedded holes 34.

Each embedding hole 34 extends through the rotor core 24 in the axial direction. The embedded holes 34 have a substantially rectangular cross-sectional shape and are each inclined with respect to the d-axis. When viewed in a cross section orthogonal to the central axis C of the rotor core 24, the two embedded holes 34 are arranged, for example, substantially in a V-shape. That is, the inner circumferential ends of the two embedding holes 34 are respectively adjacent to the d-axis and face each other with a slight gap. In the rotor core 24, a narrow magnetic path narrowing portion (bridge portion) 36 is formed between the inner peripheral side ends of the two embedded holes 34. The outer circumferential ends of the two embedded holes 34 are spaced apart from the d-axis along the circumferential direction of the rotor core 24 and located near the outer circumferential surface of the rotor core 24 and near the q-axis. Thereby, the end on the outer peripheral side of the embedded hole 34 is opposed to the outer peripheral end of the embedded hole 34 of the adjacent magnetic pole with the q axis interposed therebetween. In the rotor core 24, a narrow magnetic path narrowing portion (bridge portion) 38 is formed between the outer peripheral side end of each embedded hole 34 and the outer peripheral edge of the rotor core 24. Thus, the two embedding holes 34 are arranged such that the distance from the d-axis gradually increases from the inner circumferential end toward the outer circumferential end.

As shown in FIG. 2, each embedded hole 34 has a rectangular loading area 34 a corresponding to the cross-sectional shape of the permanent magnet 26 and the longitudinal direction of this loading area 34 a (direction perpendicular to the magnetization direction of the permanent magnet 26). Two air gaps (inner space side space 34b and outer space side space 34c) extending to both sides, and a pair of protruding into the embedded hole 34 from the inner peripheral end face of the embedded hole 34 at both ends in the longitudinal direction of the loading region 34a. And a locking projection 34d. The inner space 34 b and the outer space 34 c function as a flux barrier that suppresses the leakage of magnetic flux from the longitudinal ends of the permanent magnet 26 to the rotor core 24.

A plurality of air gap holes (cavity portions) 30 are formed in the rotor core 24. The air holes 30 extend through the rotor core 24 in the axial direction, respectively. The air gap holes 30 are located approximately at the radial center of the rotor core 24 on the q-axis, respectively, and are provided between two embedded holes 34 of adjacent magnetic poles. The void hole 30 has a polygonal, for example, triangular cross-sectional shape. The cross section of the air gap hole 30 has one side 30a orthogonal to the q-axis, and two sides 30b and 30c facing each other at intervals in the buried hole 34. Each air gap hole 30 functions as a flux barrier that makes it difficult to pass the magnetic flux, and regulates the flow of the interlinking magnetic flux of the stator 12 and the flow of the magnetic flux of the permanent magnet 26. Further, by forming the air gap hole 30, the weight reduction of the rotor core 24 can be achieved.

As shown in FIGS. 2 and 3, permanent magnets 26 are loaded in the respective embedding holes 34 and embedded in the rotor core 24. The permanent magnet 26 is formed in, for example, an elongated flat plate having a rectangular cross section, and has a length L1 substantially equal to the axial length of the rotor core 24. The permanent magnet 26 may be configured by combining a plurality of divided magnets in the axial direction (longitudinal direction), in which case the total length of the plurality of magnets is approximately equal to the axial length of the rotor core 24 It is formed in the same way. Each permanent magnet 26 is embedded over substantially the entire length of the rotor core 24. The magnetization direction of the permanent magnet 26 is orthogonal to the front and back surfaces of the permanent magnet 26.

The permanent magnet 26 is loaded in the loading area 34 a of the embedded hole 34 and fixed to the rotor core 24 by an adhesive or the like. Further, in the permanent magnet 26, a pair of corner portions respectively abut on the locking convex portion 34d. Thereby, the permanent magnet 26 is positioned in the loading area 34a. Two permanent magnets 26 located on both sides of each d-axis are arranged substantially in a V-shape. That is, the two permanent magnets 26 are arranged such that the distance from the d-axis gradually increases from the inner circumferential end toward the outer circumferential end.

Two permanent magnets 26 located on both sides of each d axis, that is, two permanent magnets 26 constituting one magnetic pole, are arranged such that the magnetization directions are the same. In addition, two permanent magnets 26 located on both sides of each q axis are arranged such that the magnetization directions are opposite to each other. By arranging the plurality of permanent magnets 26 as described above, in the outer peripheral portion of the rotor core 24, the region on each d axis is formed around one magnetic pole 40, and the region on each q axis is the interpole portion It is formed around 42. In this embodiment, the rotary electric machine 10 is a single layer distributed winding with eight poles (four pole pairs) and 48 slots, in which the front and back of the N pole and the S pole of the permanent magnet 26 are alternately arranged for each adjacent magnetic pole 40. The permanent magnet embedded type rotating electric machine wound with

As shown in FIG. 2, the distance between the outer peripheral side air gaps 34c of two adjacent magnetic poles is W1, the distance between the air gap holes 30 and the loading region 34a of the embedded holes 34 is W2, and the inner peripheries of the air gap holes 30 and the embedded holes 34 Let W3 be the distance from the side air gap 34b, and W4 be the distance between the shaft 22, ie, the inner hole 25 of the rotor core 24 and the inner space 34b of the embedded hole 34. In this case, the rotor core 24 is formed to satisfy the relationship of W1 ≦ W2, W1 ≦ W3, and W1 ≦ W4. Of the intervals W1, W2, W3 and W4, the interval W1 is the narrowest and forms the narrowest magnetic path. Further, W2 ≦ W4 and W3 ≦ W4, and a magnetic path with the widest distance W4 is formed between the inner space 34b of the embedded hole 34 and the inner hole 25. The intervals W2 and W3 may be either W2 ≦ W3 or W3 ≦ W2, and the width of the magnetic path formed between the embedded hole 34 and the air gap hole 30 is larger than the interval W1 and larger than the interval W4. It should be small.

According to the permanent magnet type rotating electrical machine 10 configured as described above, when the armature winding 18 is energized, the flux linkage from the armature winding 18 and the generated magnetic field of the permanent magnet 26 The interaction causes the rotor 14 to rotate about the shaft 22. In addition to the magnet torque caused by the attractive force and the repulsive force generated between the stator 12 and the permanent magnet 26, the rotary electric machine 10 uses the total torque of the reluctance torque to minimize the magnetic path through which the magnetic flux passes. It is rotationally driven. The rotary electric machine 10 can output electrical energy to be supplied as electrical energy as mechanical energy from the shaft 22 integrally rotating with the rotor 14. The intervals W1, W2, W3 and W4 of each part of the rotor 14 are respectively magnetic flux Corresponds to the width of the magnetic path through which By setting these intervals to W1 ≦ W2, W1 ≦ W2 and W1 ≦ W4, that is, by narrowing the interval W1 of the outer peripheral side air gaps 34c of the embedded holes 34 of the adjacent magnetic poles 40, the magnetic path of this portion The width of the As a result, the flow of the magnetic flux can be restricted, the leakage of the magnetic flux to the adjacent magnetic pole can be prevented, and the magnetic flux can efficiently flow in the magnetic path on the magnetic pole central axis (d axis) side. The magnetic flux flowing from the armature winding 18 into the rotor 14 and the magnetic flux of the permanent magnet 26 can effectively contribute to torque generation, and torque characteristics of the rotary electric machine can be improved. Furthermore, the weight of the rotor core 24 can be reduced and the weight reduction of the rotary electric machine 10 can be contributed by providing a plurality of the air gaps 30 to set the above-described interval, that is, the magnetic path width. By setting the intervals W1 ≦ W2, W1 ≦ W2 and W1 ≦ W4, the substantially triangular air gap 30 can be maximized while minimizing the reduction in torque due to the reduction in the q-axis magnetic flux.
As described above, according to the present embodiment, a permanent magnet type rotary electric machine capable of reducing the weight while maintaining the torque characteristics can be obtained.

The present invention is not limited to the above-described embodiment as it is, and at the implementation stage, the constituent elements can be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of constituent elements disclosed in the above embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components in different embodiments may be combined as appropriate.
For example, the number of magnetic poles of the rotor, the size, the shape, and the like are not limited to the above-described embodiment, and can be variously changed according to the design. The cross-sectional shape of the air gap hole 30 is not limited to a triangle, and various shapes can be selected. For example, as shown in FIG. 4, the air gap hole 30 may be a hole having a pentagonal cross sectional shape. The void hole 30 may have a shape having at least two sides 30 a and 30 b facing each other at predetermined intervals in the embedding hole 34.

Claims (4)

1. A stator having a stator core and an armature winding,
   A shaft rotatable around a central axis, a rotor core coaxially fixed to the shaft and having a plurality of magnetic poles aligned in a circumferential direction, and a plurality of cores embedded in the rotor core and disposed for each of the magnetic poles A permanent magnet, and a rotor having
   The rotor core has an inner hole coaxially formed with the central axis and into which the shaft is fitted, and a plurality of magnetic pole central axes extending radially with respect to the central axis and passing through the centers of the magnetic poles. It is provided on two sides of the magnetic pole central axis in the circumferential direction of the rotor core, and is provided between two embedded holes respectively loaded with the permanent magnets and the adjacent magnetic poles and spaced apart from each other. A plurality of void holes facing the holes;
   Each of the embedded holes has a loading region in which the permanent magnet is loaded, an inner circumferential space extending to the inner circumferential side and the outer circumferential side of the permanent magnet in a direction orthogonal to the magnetization direction of the permanent magnet, and An outer circumferential air gap, and
   The inner spaces of the two embedded holes are located opposite to each other with the magnetic pole central axis interposed therebetween, and the outer spaces of the two embedded holes are separated from the magnetic pole central axis, and the adjacent magnetic poles are embedded Adjacent to the gap on the outer periphery of the hole
   The gap between the outer periphery of the buried hole and the outer gap of the buried hole of the adjacent magnetic pole is W1, the gap between the gap and the loading region of the buried hole is W2, the inner periphery of the gap and the buried hole Assuming that the distance from the air gap is W3 and the distance between the inner hole of the rotor core and the inner air gap of the embedded hole is W4, the rotor core is W1 ≦ W2, W1 ≦ W3, W1 ≦ W4. The rotating electrical machine being formed on.
2. The rotary electric machine according to claim 1, wherein the air gap hole is formed in a cross-sectional shape having at least two sides facing each other at a distance from the embedded hole.
3. The two embedded holes and two permanent magnets provided on both sides of each magnetic pole central axis are arranged in line symmetry with respect to the magnetic pole central axis, and the magnetic poles are arranged from the inner peripheral end toward the outer peripheral end The rotating electrical machine according to claim 1, wherein the rotating electrical machine is arranged such that the distance from the central axis gradually increases.
4. The electric rotating machine according to any one of claims 1 to 3, wherein the permanent magnet is formed in a plate shape having a rectangular cross-sectional shape and extends over the entire axial length of the rotor core.

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