WO2019123961A1

WO2019123961A1 - Rotor and motor

Info

Publication number: WO2019123961A1
Application number: PCT/JP2018/043031
Authority: WO
Inventors: 邦明田中
Original assignee: 日本電産株式会社
Priority date: 2017-12-21
Filing date: 2018-11-21
Publication date: 2019-06-27
Also published as: CN111492562A; JPWO2019123961A1

Abstract

A rotor of a consequent-type motor, comprising: a shaft that rotates about a central axis extending along the vertical direction; a rotor core fixed to the shaft; and a plurality of magnets encased in the rotor core, the magnets being provided at intervals in the circumferential direction around the central axis. On the rotor core, a salient pole part projecting radially outward about the central axis is provided between mutually adjacent magnets in the circumferential direction, an iron core part is provided radially outward of the magnets, and the circumferential direction width of the iron core part is greater than the circumferential direction width of the salient pole part. FIG. 2

Description

Rotor and motor

The present invention relates to a rotor and a motor.

The rotor of the motor includes a rotor core that rotates with the shaft, and a plurality of magnets provided in the circumferential direction of the rotor core. Among such rotors, so-called consistent rotors are known. For example, Patent Document 1 discloses a consistent type rotor in which salient poles are provided between magnets adjacent to each other in the circumferential direction. The rotor has a magnet as one magnetic pole and a salient pole as the other magnetic pole.

Japanese Unexamined Patent Publication No. 2012-227989

In the above-mentioned consistent type rotor, a plurality of magnets provided circumferentially, and generally comprising one magnetic pole and the other magnetic pole alternately (hereinafter, such a rotor is a full magnet type) There is a problem that vibration and noise tend to increase as compared with the rotor). In the case of a consistent type rotor, if the width in the circumferential direction of the real pole portion (magnetic pole with magnet) and the pseudo pole portion (magnetic pole only with iron core without magnet) is the same, the pseudo pole portion crosses over to the stator There is a difference between the flux density of the flux and the flux density of the flux that is interrelated from the real pole to the stator. As a result, the electromagnetic force in the radial direction between the rotor and the stator varies between the actual pole part and the pseudo pole part, and the rotation of the rotor, the torque generated, etc. are not constant, which causes the vibration and noise to increase. Become.

An object of the present invention is to provide a rotor and a motor capable of suppressing vibration and noise at the time of operation.

One aspect of the rotor according to the present invention is a rotor of a consistent type motor, which is contained in a shaft rotating around a central axis extending along the vertical direction, a rotor core fixed to the shaft, and the rotor core And a plurality of magnets provided at intervals in the circumferential direction around the central axis, and in the rotor core, a radial direction centering on the central axis between the magnets adjacent to each other in the circumferential direction. A salient pole portion protruding outward of the magnet is provided, and an iron core portion is provided radially outside the magnet, and a circumferential width of the iron core portion is larger than a circumferential width of the salient pole portion.

One aspect of the motor of the present invention includes the above-described rotor, and a stator that faces the rotor in the radial direction via a gap.

According to one aspect of the present invention, a rotor and a motor are provided that can suppress vibration and noise during operation.

FIG. 1 is a schematic cross-sectional view of a motor according to an embodiment. FIG. 2 is a cross-sectional view of the motor of one embodiment. FIG. 3 is a cross-sectional view of the rotor of one embodiment. FIG. 4 is a graph showing a change in magnetic flux density in the circumferential direction of the rotor when the width in the circumferential direction of the core portion is made larger than the width in the circumferential direction of the salient pole in the rotor of one embodiment. FIG. 5 is a graph showing the change (distribution) of the magnetic flux density in the circumferential direction of the rotor 13 when the width in the circumferential direction of the iron core and the width in the circumferential direction of the salient pole are equal in the rotor of the embodiment. It is. FIG. 6 is a cross-sectional view of a rotor of a modification of one embodiment. FIG. 7 is a graph showing a change in magnetic flux density in the circumferential direction of the rotor when the width in the circumferential direction of the core portion is made larger than the width in the circumferential direction of the salient pole in the rotor of the modified example of one embodiment. It is.

FIG. 1 is a schematic cross-sectional view of a motor 10 according to the present embodiment. As shown in FIG. 1, a motor (consistent motor) 10 includes a housing 11, a stator 12, a rotor 13 provided with a shaft 20 disposed along a central axis J extending in the vertical direction, and a bearing holder 14. And

bearings

15 and 16. The shaft 20 is rotatably supported by the

bearings

15 and 16. The shaft 20 has a cylindrical shape extending in a direction along the central axis J.

In the following description, a direction parallel to the central axis J is simply referred to as “axial direction” or “vertical direction”, a radial direction centered on the central axis J is simply referred to as “radial direction”, and the central axis J is centered The circumferential direction to be taken, that is, around the axis of the central axis J is simply referred to as "circumferential direction". Furthermore, in the following description, “plan view” means a state viewed from the axial direction. In the following drawings, in order to make each structure intelligible, the scale, the number, etc. in an actual structure and each structure may be made different.

FIG. 2 is a cross-sectional view of the motor of the present embodiment. As shown in FIG. 2, the stator 12 faces the rotor 13 in the radial direction outside the rotor 13 with a gap in between. The stator 12 includes a plurality of teeth 17 spaced apart in the circumferential direction, and a coil 18 wound around the teeth 17. The teeth 17 radially face the rotor 13. The coil 18 generates a magnetic field to be applied to the rotor 13. In the present embodiment, for example, twelve teeth 17 and coils 18 are provided. That is, the motor 10 of the present embodiment has 12 slots.

FIG. 3 is a cross-sectional view of the rotor of the present embodiment. In addition, illustration of the shaft 20 is abbreviate | omitted in FIG. As shown in FIGS. 2 and 3, the rotor 13 includes a shaft 20 (see FIG. 2), a rotor core 30, and a plurality of magnets 50 included in the rotor core 30.

The rotor core 30 has a columnar shape extending in the axial direction. Although not shown, the rotor core 30 is configured, for example, by laminating a plurality of plate members in the axial direction. As shown in FIG. 3, the rotor core 30 includes a fixing hole 31, a magnet housing 35, a first projection (iron core) 37, and a second projection (protruding pole) 38.

The fixing hole 31 penetrates the rotor core 30 in the axial direction. The shape viewed along the axial direction of the fixing hole 31 is a circular shape centering on the central axis J. The shaft 20 (see FIG. 2) is passed through the fixing hole 31. The inner peripheral surface of the fixing hole 31 is fixed to the outer peripheral surface of the shaft 20. The rotor core 30 is thereby fixed to the shaft 20.

The magnet housing portion 35 houses the magnet 50. A plurality of magnet housing portions 35 are provided on the outer peripheral portion of the rotor core 30 at intervals in the circumferential direction. The plurality of magnet housing portions 35 are arranged at equal intervals in the circumferential direction. The plurality of magnet housing portions 35 are arranged at positions equidistantly in the radial direction from the central axis J, and are arranged in a so-called concentric manner. The number of magnet housings 35 provided in the rotor core 30 is, for example, five.

The magnet housing 35 extends in the axial direction. The magnet housing portion 35 is a through hole penetrating the rotor core 30 in the axial direction, but may be a bottomed hole formed in a part of the rotor core 30 in the axial direction. The magnet housing portion 35 includes an inner support surface 35a, an outer support surface 35b, and

end support surfaces

35c and 35c. The inner support surface 35 a is provided radially inward in the magnet housing portion 35. The inner support surface 35 a is a flat surface orthogonal to the radial direction. The outer side support surface 35b is provided in parallel with the inner side support surface 35a at intervals in the radial direction with respect to the inner side support surface 35a. The outer side support surface 35b is a flat surface orthogonal to the radial direction. The

end support surfaces

35c, 35c extend radially outward from both circumferential ends of the inner support surface 35a. The end support surface 35c is provided only on a part of the inner support surface 35a in the direction connecting the inner support surface 35a and the outer support surface 35b. For this reason, the magnet housing portion 35 is provided with an opening 35d that opens in the circumferential direction between the end support surface 35c and the outer support surface 35b. The circumferential intervals of the plurality of magnet housing portions 35 are, for example, equal to one another. The number of the plurality of magnet housings 35 is, for example, five.

The first protrusion 37 and the second protrusion 38 are provided on the outer peripheral portion of the rotor core 30. The first protrusions 37 are disposed radially outward of the magnets 50 housed in the respective magnet housings 35. The first projection 37 is made of the same material as the rotor core 30. The first protrusion 37 is provided as an iron core located on the radially outer side of the magnet 50. The first protrusion 37 protrudes radially outward. The first protrusion 37 includes extending

surfaces

37a and 37a and an outer peripheral surface 37b. The extending surfaces 37 a and 37 a extend radially outward from both circumferential ends of the outer support surface 35 b of the magnet housing portion 35. The outer circumferential surface 37b bulges radially outward from the extending

surfaces

37a, 37a on both sides in the circumferential direction. The outer peripheral surface 37b is an arc having a curvature radius R1 centered on the central axis J when viewed from the axial direction. The first projection 37 continuously extends in a uniform cross-sectional shape from one axial end of the rotor core 30 to the other axial end of the rotor core 30.

The dimension T1 in the radial direction between the radially outer side surface 50b of the magnet 50 and the outer peripheral surface of the rotor core 30, ie, the outer peripheral surface 37b of the first projection 37 is smaller than the thickness T2 in the radial direction of the magnet 50 . That is, the dimension T1 in the radial direction of the first protrusion 37 as the core portion is smaller than the thickness T2 in the radial direction of the magnet 50.

The second protrusions 38 are located between the magnets 50 adjacent to each other in the circumferential direction. The second projection 38 protrudes radially outward. The outer peripheral surface 38a on the radially outer side of the second protrusion 38 has an arc shape with a curvature radius R2 centered on a point C set radially outward of the central axis J when viewed from the axial direction. The point C is disposed on a line L passing through the center of the circumferential direction of the magnets 50 adjacent to each other in the circumferential direction from the central axis J of the rotor core 30 when viewed from the axial direction. The second projection 38 continuously extends in a uniform cross section from one axial end of the rotor core 30 to the other axial end of the rotor core 30.

In the present embodiment, the circumferential width W1 of the first projection 37 is larger than the circumferential width W2 of the second projection 38 (W1> W2). The curvature radius R2 of the outer peripheral surface 38a of the second projection 38 is smaller than the curvature radius R1 of the outer peripheral surface 37b of the first projection 37 (R1> R3). As shown in FIG. 2, in the radial direction, the dimension S2 of the gap between the second projection 38 and the tooth 17 is the same as the dimension S1 of the gap between the first projection 37 and the tooth 17 (S1 = S2) .

The rotor core 30 is provided with a recess 39. The recess 39 is provided on the outer peripheral portion of the rotor core 30. The recess 39 is provided between the first protrusion 37 and the second protrusion 38 in the circumferential direction. That is, the recess 39 is provided on both sides in the circumferential direction of the second protrusion 38. The recess 39 is recessed radially inward of the first protrusion 37 and the second protrusion 38.

The rotor core 30 is provided with a plurality of holes 40 radially outside the fixing hole 31 and radially inside the magnet housing portion 35. The plurality of holes 40 are arranged at equal intervals in the circumferential direction. In the present embodiment, the rotor core 30 is provided with ten holes 40. Each hole 40 extends axially and penetrates the rotor core 30 in the axial direction.

The magnet 50 is a rectangle whose transverse cross section is a radial direction as the longitudinal direction, and is a substantially square pole extending in the axial direction. The magnet 50 is inserted into the magnet housing portion 35. Thereby, the magnet 50 is included in the outer peripheral portion of the rotor core 30. Each magnet 50 is arrange | positioned between the 2nd projection parts 38 adjacent to the circumferential direction. The plurality of magnets 50 are arranged at equal intervals in the circumferential direction. That is, the plurality of magnets 50 are provided at intervals in the circumferential direction around the central axis J. In the present embodiment, the number of magnets 50 provided on the rotor 13 is five.

The radially inner side surface 50 a of the magnet 50 contacts the inner support surface 35 a of the magnet housing portion 35. The radially outer side surface 50 b of the magnet 50 contacts the outer support surface 35 b of the magnet housing portion 35. A part of the end surfaces 50 c on both sides in the circumferential direction of the magnet 50 is in contact with the end support surface 35 c of the magnet housing portion 35. The magnet 50 is positioned in the circumferential direction and the radial direction by being housed in the magnet housing portion 35. The end surfaces 50c on both sides in the circumferential direction of the magnet 50 have an outer peripheral side end surface 50d located on the radially outer side of the end support surface 35c. The outer peripheral side end face 50 d is exposed to the recess 39 from the opening 35 d of the magnet housing portion 35.

As described above, the rotor 13 of the present embodiment includes ten magnetic poles configured by the magnets 50 and the second protrusions 38.

FIG. 4 shows the change (distribution) of the magnetic flux density in the circumferential direction of the rotor 13 when the circumferential width W1 of the first projection 37 is larger than the circumferential width W2 of the second projection 38. It is a graph. As shown in FIG. 4, in the rotor 13 of the present embodiment, a first projection 37 which is an actual pole provided with the magnet 50 and a second projection 38 which is a pseudo pole which is not provided with the magnet 50. The magnetic flux density is approximately equal.

FIG. 5 shows the circumference of the rotor 13 in the case where the width W1 in the circumferential direction of the first protrusion 37 and the width W2 in the circumferential direction of the second protrusion 38 are equal, as a comparison object with the rotor 13 of this embodiment. It is a graph which shows the change (distribution) of the magnetic flux density in direction. As shown in FIG. 5, in the rotor 13 in which the width W1 in the circumferential direction of the first protrusion 37 and the width W2 in the circumferential direction of the second protrusion 38 are equal to each other, The magnetic flux density is different between the one protrusion 37 and the second protrusion 38 which is a pseudo pole portion in which the magnet 50 is not provided. Specifically, the magnetic flux density in the first protrusion 37 is higher than the magnetic flux density in the second protrusion 38. This is because the amount of magnetic flux interlinked to the stator 12 from the second protrusion 38 side is larger than the amount of magnetic flux interlinked to the stator 12 from the first protrusion 37 side.

According to the present embodiment, in the rotor 13 of the consistent type motor 10, the magnet 50 is contained in the rotor core 30, and the circumferential width W1 of the first protrusion 37 provided on the radially outer side of the magnet 50 is the first The width W2 is larger than the circumferential width W2 of the two protrusions 38. As a result, the amount of magnetic flux interlinked from the second projection 38 to the stator 12 can be reduced, and the amount of magnetic flux interlinked from the first projection 37 and the second projection 38 to the stator 12 can be made uniform. As a result, it is possible to reduce the variation of the radial force caused by the non-uniformity of the magnetic flux, and it is possible to reduce the vibration and noise during operation of the rotor 13. Therefore, the rotor 13 and the motor 10 capable of suppressing vibration and noise during operation are provided.

In the rotor 13 of the present embodiment, the dimension T1 in the radial direction between the radially outer side surface 50b of the magnet 50 and the outer peripheral surface of the rotor core 30, ie, the outer peripheral surface 37b of the first protrusion 37 It is smaller than the radial thickness T2. Thus, the magnet 50 can be brought closer to the stator 12 while being held in the magnet housing portion 35. Therefore, the magnetic flux is prevented from leaking except between the magnet 50 and the teeth 17.

According to the present embodiment, the recess 39 that is recessed inward in the radial direction is provided on both sides in the circumferential direction of the second protrusion 38. Thereby, the magnetic flux flowing between the stator 12 and the magnet 50 can be prevented from being diffused, and the flow of the magnetic flux can be made smooth.

According to the present embodiment, the outer peripheral side end face 50 d which is at least a part of the magnet 50 is exposed to the recess 39. Thereby, the magnetic flux flows directly between the magnet 50 and the stator 12 without passing through a part of the rotor core 30. As a result, the flow of magnetic flux can be made smooth.

According to the present embodiment, the magnet 50 is housed in the magnet housing portion 35. Thereby, when the rotor 13 rotates at high speed, the magnet 50 is prevented from being detached from the rotor core 30 by the centrifugal force.

According to the motor 10 of the present embodiment, the dimension S2 of the gap between the second projection 38 and the teeth 17 in the radial direction is the same as the dimension S1 of the gap between the first projection 37 and the teeth 17. Thereby, the electromagnetic force (radial force) in the radial direction between the rotor 13 and the stator 12 is made uniform between the portion where the first projection 37 is provided and the portion where the second projection 38 is provided. can do. As a result, it is possible to reduce vibration and noise generated in the motor 10.

[Modification of the embodiment]
(Modification) FIG. 6 is a cross-sectional view of a rotor of a modification of the embodiment described above. FIG. 7 shows a change in magnetic flux density in the circumferential direction of the rotor when the width in the circumferential direction of the core portion is made larger than the width in the circumferential direction of the salient pole in the rotor of the modified example of the embodiment described above. It is a graph. The rotor 13 </ b> B of this modification mainly differs from the above-described rotor 13 in the structure of the second protrusion 38 </ b> B. In addition, about the component of the aspect same as the above-mentioned embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 6, the rotor 13B of the motor 10 is provided with a first projection 37 and a second projection (a salient pole) 38B on the outer peripheral portion of the rotor core 30B. In a modification of the present embodiment, the circumferential width W1 of the first projection 37 is larger than the circumferential width W3 of the second projection 38B (W1> W3). The curvature radius R1 of the outer peripheral surface 37b of the first projection 37 and the curvature radius R3 of the outer peripheral surface 38a of the second projection 38B are equal (R1 = R3).

As shown in FIG. 7, in the rotor 13B of this embodiment, a first projection 37 which is an actual pole provided with the magnet 50 and a second projection 38B which is a pseudo pole where the magnet 50 is not provided. The magnetic flux density is approximately equal.

Also in such a configuration, as in the rotor 13 and the motor 10 of the above-described embodiment, it is possible to make uniform the amount of magnetic flux interlinked to the stator 12 from the first projection 37 and the second projection 38B. As a result, it is possible to reduce the variation of the radial force caused by the non-uniformity of the magnetic flux, and it is possible to reduce the vibration and noise during operation of the rotor 13B. Therefore, the rotor 13B and the motor 10 capable of suppressing vibration and noise at the time of operation are provided.

Although one embodiment of the present invention has been described above, each configuration and combination thereof in the embodiment is an example, and addition, omission, substitution, and other configurations can be made without departing from the spirit of the present invention. Changes are possible. The present invention is not limited by the embodiments.

For example, the application of the motor provided with the rotor of the embodiment described above and its variation is not particularly limited. The motor including the rotors of the above-described embodiment and the modification thereof is mounted on, for example, an electric pump, an electric power steering, and the like.

DESCRIPTION OF SYMBOLS 10 ... Motor (consistent type motor), 12 ... Stator, 13, 13B ... Rotor, 17 ... Teeth, 20 ... Shaft, 30, 30B ... Rotor core, 35 ... Magnet accommodation part, 37 ... 1st projection part (iron core part), 37b: outer peripheral surface, 38, 38B: second projection (salicy pole), 38a: outer peripheral surface, 39: recess, 50: magnet, J: central axis, R1, R2, R3: radius of curvature, S1, S2: Dimension of gap, W1, W2 ... circumferential width, T1 ... dimension, T2 ... thickness

Claims

It is a rotor of a consistent type motor,
A shaft rotating about a central axis extending along the vertical direction;
A rotor core fixed to the shaft;
And a plurality of magnets included in the rotor core and provided at intervals in the circumferential direction around the central axis,
The rotor core is provided with salient pole portions protruding outward in the radial direction centering on the central axis between the magnets adjacent to each other in the circumferential direction.
An iron core portion is provided radially outward of the magnet,
The rotor, wherein the circumferential width of the iron core portion is larger than the circumferential width of the salient pole portion.
The rotor according to claim 1, wherein a curvature radius of an outer peripheral surface of the salient pole portion is smaller than a curvature radius of an outer peripheral surface of the iron core portion.
The rotor according to claim 1, wherein a dimension in a radial direction between a radially outer side surface of the magnet and an outer peripheral surface of the rotor core is smaller than a radial thickness of the magnet.
The rotor according to any one of claims 1 to 3, wherein the rotor core is provided with recessed portions that are recessed inward in the radial direction and located on both sides in the circumferential direction of the salient pole portion.
The rotor according to claim 4, wherein at least a part of the magnet is exposed to the recess.
The rotor according to any one of claims 1 to 5, wherein the rotor core has an axially extending magnet housing, and at least a part of the magnet is housed in the magnet housing.
A rotor according to any one of claims 1 to 6;
And a stator facing the rotor in the radial direction via a gap.
The stator has teeth that face the rotor in the radial direction, and in the radial direction, the dimension of the gap between the salient pole portion and the teeth is the same as the dimension of the gap between the iron core portion and the teeth The motor according to claim 7, which is