CN116207885A

CN116207885A - Rotor, rotating electrical machine, and driving device

Info

Publication number: CN116207885A
Application number: CN202211492072.3A
Authority: CN
Inventors: 條野雄介
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2021-11-30
Filing date: 2022-11-25
Publication date: 2023-06-02
Also published as: JP2023080869A; DE102022131575A1

Abstract

One embodiment of the rotor of the present invention includes: the rotor core body is provided with a magnet hole, and the magnet hole axially extends by taking the central axis as the center and penetrates through the central axis in the axial direction; a magnet disposed in the magnet hole; and a first foam sheet and a second foam sheet, the first foam sheet and the second foam sheet being disposed between the inner wall of the magnet hole and the magnet. A lamination region is provided on at least a part of the outer periphery of the magnet, and the lamination region is provided for laminating both the first foam sheet and the second foam sheet.

Description

Rotor, rotating electrical machine, and driving device

Technical Field

The present invention relates to a rotor, a rotating electrical machine, and a driving device.

Background

Conventionally, an IPM (interior permanent magnet) type rotor is known in which a magnet is embedded in a rotor core. As a method of fixing a magnet to a magnet hole of a rotor core, patent document 1 discloses a method of using a foamable resin sheet.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2006-311782.

Disclosure of Invention

Technical problem to be solved by the invention

The load applied to the magnets when the rotor rotates may vary according to the specifications of the rotor, the arrangement of the magnets, etc. of the outer diameter, the rotational speed, etc. Accordingly, it is preferable to use the most appropriate magnet holding force for the magnet holding force of the foam sheet for holding the magnet, depending on the rotor specification and the arrangement of the magnets. However, in the case where plural types of foam sheets are prepared, there is a problem in that supply of foam sheets and inventory management become difficult.

An object of the present invention is to provide a rotor, a rotary electric machine, and a driving device capable of holding a magnet with characteristics optimal for rotor specifications and magnet arrangement by using a small number of types of foam sheets.

Technical proposal adopted for solving the technical problems

One embodiment of the rotor of the present invention includes: the rotor comprises a rotor core body, wherein the rotor core body is provided with a magnet hole, and the magnet hole axially extends by taking a central axis as a center and penetrates through the center; a magnet disposed in the magnet hole; and a first foam sheet and a second foam sheet, which are disposed between the inner wall of the magnet hole and the magnet. A lamination region is provided on at least a part of the outer periphery of the magnet, and the lamination region is used for laminating the first foam sheet and the second foam sheet.

One embodiment of the rotating electrical machine of the present invention includes: the rotor; and a stator disposed radially outward of the rotor.

One embodiment of the drive device of the present invention includes the rotating electric machine and a transmission device connected to the rotor.

Effects of the invention

According to one aspect of the present invention, a rotor, a rotating electrical machine, and a driving device can be provided, in which a magnet can be held with characteristics optimal for the rotor specification and magnet arrangement by using fewer types of foam pieces.

Drawings

Fig. 1 is a schematic configuration diagram schematically showing a driving device according to an embodiment.

Fig. 2 is a plan view of a rotor of an embodiment as viewed from the axial direction.

Fig. 3 is a top view illustrating a portion of a rotor of an embodiment.

Fig. 4 is a side view showing a foam sheet.

Fig. 5 is a plan view showing a part of a rotor according to a first modification.

Fig. 6 is a plan view showing a part of a rotor according to a second modification.

Fig. 7 is a plan view showing a part of a rotor according to a third modification.

Symbol description

10-turn motor

30. 130, 230, 330 rotors

32. 332 rotor core

36 magnet

36a first long side surface

36b second long side surface

36c first short side surface

36d second short side surface

37. 137, 237, 337 foaming sheet

37d adhesive layer

37dA first adhesive layer

37dB second adhesive layer

37A, 137A, 237A, 337A first foaming sheet

37B, 137B, 237B, 337B second foaming sheet

38. 338 magnet holes

40 stator

60 transfer device

100 driving device

A lamination area

B Single sheet area

J central axis.

Detailed Description

Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the accompanying drawings. In the following description, a description will be given of a vertical direction with reference to a positional relationship in a case where the driving device of the embodiment is mounted on a vehicle on a horizontal road surface. In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction.

The central axis J appropriately shown in the drawing is an imaginary axis. The central axis J extends in the Y-axis direction orthogonal to the vertical direction. In the following description, unless otherwise specified, a direction parallel to the central axis J is simply referred to as an "axial direction", a radial direction centered on the central axis J is simply referred to as a "radial direction", and a circumferential direction centered on the central axis J, that is, a direction around the central axis J is simply referred to as a "circumferential direction".

The arrow θ appropriately indicated in each figure indicates the circumferential direction. In the following description, a side that advances counterclockwise about the central axis J when viewed from the left, that is, a side toward which the arrow θ faces (+θ side) is referred to as "circumferential side", and a side that advances clockwise about the central axis J when viewed from the left, that is, a side opposite to the side toward which the arrow θ faces (- θ side) is referred to as "circumferential side".

< drive device >)

As shown in fig. 1, the driving device 100 of the present embodiment includes a rotary electric machine 10, a transmission device 60, and a housing 6. The drive device 100 is mounted on a vehicle using a motor as a power source, such as a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an Electric Vehicle (EV), and is used as a power source thereof.

Transmission device

The transmission device 60 is connected to the rotor 30 of the rotary electric machine 10. The transmission device 60 transmits the rotation of the rotor 30 to an axle 64 of the vehicle. The transmission device 60 includes a reduction gear 62 connected to the rotor 30, and a differential gear 63 connected to the reduction gear 62. The differential gear 63 has a ring gear 63a.

< Shell >

The housing 6 has a gear housing 61 accommodating the transmission device 60 and a motor housing 65 accommodating the rotary electric machine 10. The oil O is accumulated in the lower region of the gear housing 61. The oil O circulates in the refrigerant flow path 90. The oil O serves as a refrigerant for cooling the rotary electric machine 10. Further, the oil O serves as lubricating oil for the reduction gear 62 and the differential gear 63.

The casing 6 is provided with a refrigerant flow path 90 for the oil O circulation. The refrigerant flow path 90 extends across the inside of the motor case 65 and the inside of the gear case 61. The refrigerant flow path 90 is a path through which the oil O stored in the gear housing 61 is supplied to the rotating electrical machine 10 and returns to the gear housing 61 again. The refrigerant flow path 90 is provided with a pump 71 for pumping the oil O, a cooler 72 for cooling the oil O, and a refrigerant supply unit 50 for supplying the oil O to the rotating electrical machine 10.

The oil O stored in the gear housing 61 is sucked up by the pump 71 and flows into the cooler 72. The oil O flowing into the cooler 72 cools in the cooler 72 and then flows into the refrigerant supply unit 50. A part of the oil O flowing into the refrigerant supply portion 50 is supplied to the stator 40. Further, another portion of the oil O flowing into the refrigerant supply portion 50 flows into the inside of the shaft 31. A part of the oil O flowing into the inside of the shaft 31 is splashed to the stator 40 by the centrifugal force of the shaft 31. Further, the other part of the oil O flowing into the inside of the shaft 31 is discharged from the end of the shaft 31 into the inside of the gear housing 61, and is stored again in the gear housing 61. The oil O supplied to the rotating electrical machine 10 takes heat from the rotating electrical machine 10. The oil O cooled by the rotating electric machine 10 falls downward and returns to the gear housing 61.

The present invention is not limited to the above-described embodiments, and, for example, the following description may be made with modifications in the structure within the scope of the present invention. In the drawings of the respective modifications, the same components as those of the above-described embodiments are denoted by the same reference numerals, and the differences will be mainly described below.

< rotating Electrical machine >

The rotary electric machine 10 is a part that drives the driving device 100. In the present embodiment, the rotary electric machine 10 has both a function as an electric motor and a function as a generator.

The rotary electric machine 10 includes a rotor 30 rotatable about a central axis J, a stator 40 positioned radially outward of the rotor 30, and a refrigerant supply portion 50.

(stator)

The stator 40 is opposed to the rotor 30 with a gap therebetween in the radial direction. The stator 40 is fixed to the inside of the motor housing 65. The stator 40 has a stator core 41 and a coil 42. The stator core 41 has a ring shape surrounding the central axis J of the rotary electric machine 10. The coil 42 is mounted on the stator core 41 via an insulating material, not shown.

(rotor)

As shown in fig. 2, the rotor 30 includes an annular rotor core 32 centered on a central axis J, a plurality of magnets 36, a plurality of foam sheets 37, and a shaft 31 (omitted from fig. 2). Further, the rotor 30 includes a plurality of magnetic poles 3 arranged in the circumferential direction. The rotor 30 of the present embodiment includes eight magnetic poles 3. One pole 3 contains three magnets 36. The three magnets 36 of one magnetic pole 3 are arranged to be mirror-symmetrical about the magnetic pole center line L. Here, the magnetic pole center line L is an imaginary line passing through the circumferential center of the magnetic pole 3 and the center axis J and extending in the radial direction. In the present embodiment, the magnetic pole center line L is substantially parallel to the d-axis, which is the direction of the main magnetic flux.

(rotor core)

The rotor core 32 extends in the axial direction about the central axis J. The rotor core 32 has a central hole 32a, and the central hole 32a penetrates the rotor core 32 in the axial direction. The center hole 32a is substantially circular centered on the center axis J. The shaft 31 (refer to fig. 1) passes through the center hole 32a in the axial direction.

The rotor core 32 is made of a magnetic material. Although not particularly shown, the rotor core 32 has a plurality of laminated bodies laminated in the axial direction. The laminate is a plate-like member. The plate surface of the laminate faces in the axial direction. The laminate has an approximately circular annular plate shape centered on the central axis J. The laminate is, for example, an electromagnetic steel sheet.

The rotor core 32 is provided with a plurality of magnet holes 38. Each of the magnet holes 38 is disposed in a portion of the rotor core 32 other than the center hole 32a. More specifically, the magnet holes 38 are arranged radially outward of the center hole 32a and circumferentially at intervals when viewed from the axial direction. Each magnet hole 38 penetrates the rotor core 32 in the axial direction. The magnet holes 38 are provided with a magnet 36 and a foam sheet 37, respectively.

As shown in fig. 3, the inner wall of each magnet hole 38 has a first wall surface 38a, a second wall surface 38b, and a pair of protrusions 38d.

The first wall surface 38a faces radially outward. The first wall surface 38a is provided with a recess 38c. The recess 38c is disposed in the center of the first wall surface 38a when viewed in the axial direction. The recess 38c has a groove shape extending in the axial direction. In the present embodiment, the shape of the cross section of the concave portion 38c perpendicular to the axial direction is, for example, a semicircle or a semiellipse. In addition, the recess 38c does not necessarily need to be provided on the inner wall of the magnet hole 38.

The second wall surface 38b faces the first wall surface 38 a. That is, the second wall surface 38b faces radially inward. The magnet 36 is disposed between the first wall surface 38a and the second wall surface 38b.

The protrusions 38d are provided with a pair at the inner wall of the magnet hole 38. The pair of projections 38d are disposed at both end portions of the first wall surface 38a as viewed in the axial direction. The protrusion 38d protrudes from the first wall surface 38a toward the second wall surface 38b. The protrusion 38d extends in the axial direction. In the present embodiment, the protrusion 38d is provided over the entire axial length of the magnet hole 38. The magnet 36 is disposed between a pair of projections 38d.

The magnet hole 38 is provided with a magnetism blocking bridge portion 38e. The magnetism isolating bridge portions 38e are arranged on both side portions of the magnet 36 when viewed in the axial direction. In the present specification, the "magnetic shielding bridge portion" refers to a portion capable of suppressing the flow of magnetic flux. That is, it is difficult for the magnetic flux to pass through the magnetically isolated bridge portion. The magnetic barrier bridge portion is not particularly limited as long as it can suppress the flow of magnetic flux, and may include a void portion, a nonmagnetic portion such as a resin portion, and the like. In the present embodiment, the magnetism isolating bridge portion 38e is a void portion constituted by a hole penetrating the rotor core 32 in the axial direction.

The plurality of magnet holes 38 includes a first magnet hole 38A and a second magnet hole 38B. The number of the second magnet holes 38B of the present embodiment is twice the number of the first magnet holes 38A. The three magnets 36 disposed in the three magnet holes 38 constitute one magnetic pole 3. The three magnet holes 38 in which the three magnets 36 constituting one magnetic pole 3 are arranged are referred to as a group S of magnet holes 38.

The pair of second magnet holes 38B of one group S are symmetrically arranged about the magnetic pole center line L passing through the center of the magnetic pole 3 as viewed in the axial direction. The second magnet hole 38B located on one side (+θ side) in the circumferential direction with respect to the magnetic pole center line L extends on one side (+θ side) in the circumferential direction as it goes radially outward when viewed in the axial direction. Further, the second magnet hole 38B on the other side (- θ side) in the circumferential direction with respect to the magnetic pole center line L extends toward the other side (- θ side) in the circumferential direction as it goes to the radially outer side as viewed from the axial direction. That is, the distance between the circumferential directions of the pair of second magnet holes 38B included in one group S becomes gradually larger as going radially outward. The first magnet hole 38A is arranged between the radially outer end portions of the pair of second magnet holes 38B in the circumferential direction.

(magnet)

The magnets 36 are disposed one in each of the magnet holes 38. The kind of the magnet 36 is not particularly limited. The magnet 36 may be, for example, a neodymium magnet or a ferrite magnet. In the present embodiment, the magnet 36 has a rectangular parallelepiped shape long in the axial direction. The magnet 36 extends from, for example, one axial end portion to the other axial end portion of the rotor core 32. In addition, the axial dimension of the magnet 36 may also be shorter than the axial dimension of the rotor core 32 (the axial dimension of the magnet hole 38). Further, the shape of the magnet 36 is not limited to the above-described shape.

The magnet 36 has a rectangular shape when viewed from the axial direction. The magnet 36 has

long side surfaces

36a, 36b forming long sides and

short side surfaces

36c, 36d forming short sides when viewed in the axial direction. Here, a surface of the pair of

long side surfaces

36a, 36b located radially inward and radially outward is referred to as a first long side surface 36a, and a surface located radially outward and radially inward is referred to as a second long side surface 36b. Similarly, one of the pair of

short sides

36c and 36d is referred to as a first short side 36c, and the other is referred to as a second short side 36d. That is, the magnet 36 has a first long side surface 36a, a second long side surface 36b, a first short side surface 36c, and a second short side surface 36d.

One pole 3 contains three magnets 36. In the following description, the magnet 36 disposed in the first magnet hole 38A is referred to as a first magnet 36A. Similarly, the magnet 36 disposed in the second magnet hole 38B is referred to as a second magnet 36B. That is, the rotor 30 includes a first magnet 36A disposed in the first magnet hole 38A and a second magnet 36B disposed in the second magnet hole 38B. The magnetic pole 3 includes one first magnet 36A and two second magnets 36B. The number of second magnets 36B in the present embodiment is twice the number of first magnets 36A.

In one magnetic pole 3, the first magnet 36A is disposed orthogonal to the magnetic pole center line L. Further, in one magnetic pole 3, two second magnets 36B are arranged symmetrically in the circumferential direction about the magnetic pole center line L at the radially inner side of the first magnet 36A. Further, in one magnetic pole 3, the two second magnets 36B are distant from each other as facing radially outward.

The first magnet 36A and the second magnet 36B each have a thickness direction as a magnetization direction. The first magnet 36A and the pair of second magnets 36B constituting one magnetic pole 3 are each oriented toward the same pole on the radially outer side. For example, in the case where the radially outward facing surface of the first magnet 36A is an N-pole (or S-pole), the radially outward facing surface of the pair of second magnet holes 38B is also an N-pole (or S-pole).

(foaming sheet)

The foam sheet 37 is disposed between the inner wall of the magnet hole 38 and the magnet 36. The foam sheet 37 is a sheet-like member. The foam sheet 37 is inserted into the magnet hole 38 together with the magnet 36 in a state of being attached to the outer side surface of the magnet 36.

In the present embodiment, the foam sheet 37 has a rectangular or quadrangular sheet shape extending in the axial direction. However, the foam sheet 37 is not limited to this, and may be a sheet shape such as a polygonal shape other than a quadrangle, an elliptical shape, or a circular shape. The foaming sheet 37 disposed in the magnet hole 38 is foamed by heating, thereby expanding in volume, and is cured in an expanded state. The expanded foam sheet 37 presses the magnet 36 against the inner wall of the magnet hole 38. Thereby, the foam sheet 37 holds the magnet 36 in the magnet hole 38.

As shown in fig. 4, the foam sheet 37 is configured by laminating a plurality of layers. The foam sheet 37 of the present embodiment includes a sheet-like base material portion 37a, a pair of sheet-like foam portions 37b, and a pair of adhesive layers 37d.

The base material portion 37a is film-like, and is made of, for example, resin. The base material 37a is made of, for example, polynaphthalene (PEN), polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polyimide (PI), or the like.

The pair of foaming sections 37b includes, for example, a thermosetting resin and a foaming agent that can be foamed by heating. Preferably, the foaming agent is, for example, a foaming agent that foams at a temperature lower than the curing temperature of the thermosetting resin and reaches the state of maximum expansion (maximum foaming state). Thus, in the process of temperature rise at the time of rotor heating, after foaming of the foaming agent is completed, curing of the thermosetting resin starts, and therefore, the foaming sheet 37 is stably expanded, and the magnet 36 can be stably fixed to the inner wall of the magnet hole 38 by the foaming sheet 37.

As the foaming agent for the foaming section 37b, an organic solvent having a low melting point, for example, microcapsules containing alcohol or the like can be used. Further, the thermosetting resin of the foaming portion 37b is preferably composed of a thermosetting adhesive. Examples of the thermosetting adhesive include phenolic adhesives, polyurethane adhesives, and epoxy adhesives. In addition, when an epoxy adhesive is used as a thermosetting adhesive, it is more preferable because of excellent adhesive strength, chemical resistance, and the like.

One of the pair of foaming sections 37b is disposed on one surface of the base section 37a, and the other is disposed on the other surface of the base section 37a. The surface of each foam portion 37b facing the opposite side of the base material portion 37a is provided with an adhesive layer 37d. In the present embodiment, the pair of foaming parts 37b are composed of the same material, but they may be composed of different materials.

The pair of adhesive layers 37d are provided on the foaming portion 37b. Accordingly, the foam sheet 37 of the present embodiment is provided with adhesive layers 37d on the front and rear surfaces thereof. The adhesive layer 37d is an adhesive film, and a conventionally known film can be used. The adhesive layer 37d is covered with, for example, release paper (not shown).

The foam sheet 37 of the present embodiment is provided with a pair of adhesive layers 37d on the front and back surfaces thereof. Therefore, the foam sheet 37 is bonded to be fixed to the magnet 36, and is bonded to be fixed to the inner wall of the magnet hole 38. However, the foam sheet 37 may be provided with an adhesive layer on only one of the front surface and the back surface. That is, the foam sheet 37 may be fixed to at least one of the magnet 36 and the inner wall of the magnet hole 38 by bonding with an adhesive layer.

As shown in fig. 3, the foam sheet 37 is disposed between the inner wall of the magnet hole 38 and the magnet 36. The foam sheet 37 of the present embodiment is arranged in two pieces between the outer side surface of the magnet 36 and the inner wall of the magnet hole 38.

In the present embodiment, the foam sheet 37 expanded by heating fills the gap between the magnet 36 and the magnet hole 38 when the rotor 30 is manufactured. Since the foam sheet 37 is cured in this state, the state in which the magnet 36 is held in the magnet hole 38 is maintained. Therefore, even if centrifugal force acts on the magnet 36 when the rotor 30 rotates, misalignment of the magnet 36 in the magnet hole 38 is suppressed.

The plurality of foam sheets 37 includes a first foam sheet 37A and a second foam sheet 37B. That is, the rotor 30 has a first foam sheet 37A and a second foam sheet 37B. The first foam piece 37A and the second foam piece 37B are accommodated in the magnet hole 38.

The first foam piece 37A and the second foam piece 37B are disposed between the inner wall of the magnet hole 38 and the magnet 36. The first foam sheet 37A and the second foam sheet 37B are laminated on the outer periphery of the magnet 36. The first foam sheet 37A encloses the outer periphery of the magnet 36. Further, the second foam sheet 37B encloses the outer periphery of the magnet 36 with the first foam sheet 37A interposed therebetween.

According to the present embodiment, the first foam sheet 37A is a joined sheet that covers the first long side surface 36a, the second long side surface 36b, the first short side surface 36c, and the second short side surface 36d. The second foam sheet 37B is a sheet integrally connected to cover the first long side surface 36a, the second long side surface 36B, the first short side surface 36c, and the second short side surface 36d with the first foam sheet 37A interposed therebetween.

In the present embodiment, one of the two foam sheets 37 stacked on each other, which is disposed on the inner side (the magnet 36 side), is the first foam sheet 37A, and the other foam sheet disposed on the outer side is the second foam sheet 37B. Therefore, the first foam sheet 37A is in contact with and bonded to the outer periphery of the magnet 36. On the other hand, the second foam sheet 37B is in contact with and bonded to the inner wall of the magnet hole 38. Further, the first foam sheet 37A and the second foam sheet 37B are bonded in contact with each other at the lamination interface.

The first foam piece 37A is arranged in a C-shape around the magnet 36 when viewed in the axial direction. A gap G is provided between the pair of end portions 37Aa, 37Ab of the first foam sheet 37A as viewed in the axial direction. The end portions 37Aa, 37Ab of the first foam sheet 37A face each other at a portion disposed along the first long side surface 36a.

The second foam sheet 37B is arranged in a C-shape around the magnet 36 when viewed in the axial direction. A gap G is provided between a pair of end portions 37Ba, 37Bb of the second foam sheet 37B as viewed in the axial direction. The end portions 37Ba, 37Bb of the second foam sheet 37B face each other at a portion disposed along the second long side surface 36B.

According to the present embodiment, the gaps G between the ends of the first foam sheet 37A and the second foam sheet 37B are disposed on the different

long side surfaces

36a, 36B, respectively. By disposing the gap G on the

long side surfaces

36a, 36b, the positions of the end portions 37Aa, 37Bb, 37Ba, 37Bb can be disposed farther from the corners of the magnet 36 than the case where the gap G is disposed on the

short side surfaces

36c, 36d. Therefore, in the step of attaching the first foam sheet 37A and the second foam sheet 37B to the magnet 36, the first foam sheet 37A and the second foam sheet 37B are not easily turned over, and the manufacturing process can be simplified. Further, by disposing the gap G of the first foam piece 37A and the gap G of the second foam piece 37B on different

long side surfaces

36a, 36B, the entire outer peripheral surface of the magnet 36 can be reliably covered by at least one of the first foam piece 37A and the second foam piece 37B.

In the present embodiment, both the first foam piece 37A and the second foam piece 37B are laminated between the outer periphery of the magnet 36 and the inner wall of the magnet hole 38. Here, a region where the first foam sheet 37A and the second foam sheet 37B are laminated is referred to as a lamination region a. The lamination area a of the present embodiment is the entire area of the outer periphery of the magnet 36 except for the area where the gap G between the ends of the first foam sheet 37A and the second foam sheet 37B is provided.

According to the present embodiment, a lamination area a in which two foam sheets 37 are laminated is provided between the outer periphery of the magnet 36 and the inner wall of the magnet hole 38. The magnet holding effect of holding the magnet 36 by the two foam pieces 37 in the lamination area a can be obtained superimposed. For example, when the softness of the foam parts 37B of the first foam sheet 37A and the second foam sheet 37B are different from each other, the two foam sheets 37 can protect the magnet 36 against vibrations in different frequency bands. In addition, when the adhesion of the adhesive layer 37d of the first foam sheet 37A to the magnet 36 is high and the adhesion of the adhesive layer 37d of the second foam sheet 37B to the rotor core 32 is high, the adhesion can be improved for both the magnet 36 and the rotor core 32. Further, the above-described effect can be obtained by providing the lamination area a in which the first foam sheet 37A and the second foam sheet 37B are laminated on at least a part of the outer periphery of the magnet 36.

According to the present embodiment, the first foam piece 37A and the second foam piece 37B are disposed between the first long side surface 36a of the magnet 36 and the first wall surface 38a of the magnet hole 38, between the second long side surface 36B of the magnet 36 and the second wall surface 38B of the magnet hole 38, between the first short side surface 36c of the magnet 36 and the protrusion 38d of the magnet hole 38, and between the second short side surface 36d of the magnet 36 and the protrusion 38d of the magnet hole 38, respectively. That is, the first foam piece 37A and the second foam piece 37B are laminated and arranged in all gaps between the magnet 36 and the inner wall of the magnet hole 38. According to the present embodiment, even when a force in an arbitrary direction acts on the magnet 36, the magnet 36 can be firmly held in the magnet hole 38. Further, by the cushioning effect of the foam parts 37B of the first foam sheet 37A and the second foam sheet 37B, even when the magnet 36 acts on an impact force in an arbitrary direction, the magnet 36 can be prevented from being damaged. That is, according to the present embodiment, the effect of laminating two foam sheets 37 on the entire magnet 36 can be obtained.

According to the present embodiment, the holding force of the magnet 36 can be adjusted by lamination of the foam sheet 37 between the inner wall of the magnet hole 38 and the outer peripheral surface of the magnet 36. Therefore, by changing the number of laminated blocks of the foam sheets 37 and the type of foam sheets 37 to be laminated according to the specifications of the rotor 30 such as the outer diameter and the rotation speed, it is possible to realize the magnet holding force suited to various specifications by preparing only the foam sheets 37 of the minimum type. This can simplify the supply of the foam sheet and the management of the stock.

In the present embodiment, at least one of the type and thickness of the foamed part 37B and the type of the adhesive layer 37d shown in fig. 4 may be different for the first foamed sheet 37A and the second foamed sheet 37B. In this case, the magnet holding force of the first foam sheet 37A and the magnet holding force of the second foam sheet 37B are different from each other.

In this specification, the magnet holding force means a force for holding the magnet 36 inside the magnet hole 38 by the foam sheet 37. The magnet holding force can be measured as a force when the magnet 36 starts to move in the magnet hole 38 by applying an axial force to the magnet 36 in the magnet hole 38, for example. Further, whether or not the magnet holding forces of the two foam sheets 37 are different from each other is determined by whether or not the other magnet holding force is higher than, for example, 10% or more with respect to the smaller one of the magnet holding forces. The ratio of the reference constituting whether or not the two magnet holding forces are different is not limited to 10%, and may be, for example, several%.

Here, a method for measuring the magnet holding force of the first foam sheet 37A and the second foam sheet 37B will be described in more detail. First, a foam sheet 37 to be measured is attached between the outer periphery of the magnet 36 and the inner wall of the magnet hole 38 by an adhesive layer 37d, and then the foam portion 37b is foamed to hold the magnet 36. At this time, only one of the first foam piece 37A and the second foam piece 37B is disposed between the magnet 36 and the inner wall of the magnet hole 38, and the magnet 36 is held. Then, a force is applied to the magnet 36 in the axial direction from the opening on one side in the axial direction of the magnet hole 38. The force at which the axial force applied to the magnet 36 is gradually increased so that the magnet 36 is displaced in the axial direction is recorded as a magnet holding force.

In the foam sheet 37, when the type of the foaming portion 37b is changed, the expansion ratio at the time of foaming also changes. Therefore, by changing the kind of the foaming portion 37b, the stress of the foaming sheet 37 that presses the magnet 36 to the magnet hole 38 also changes, and the magnet holding force of the foaming sheet 37 changes.

In the foam sheet 37, if the thickness of the foam portion 37b is changed, the thickness of the foam portion 37b after foaming is also changed. Therefore, by changing the thickness of the foamed part 37b, the stress of the foamed sheet 37 that presses the magnet 36 to the magnet hole 38 also changes, and the magnet holding force of the foamed sheet 37 changes.

In the foam sheet 37, if the type of the adhesive layer 37d is changed, the adhesive force between the foam sheet 37 and the magnet 36 or the adhesive force between the foam sheet 37 and the inner wall of the magnet hole 38 is changed. Therefore, by changing the kind of the adhesive layer 37d, the magnet holding force of the foam sheet 37 is changed.

Here, the portion of the adhesive layer 37d of the first foam sheet 37A that adheres to the surface of the magnet 36 is referred to as a first adhesive layer 37dA. Further, a portion of the adhesive layer 37d of the second foam sheet 37B that adheres to the inner wall of the magnet hole 38 is referred to as a second adhesive layer 37dB. That is, the first foam sheet 37A has the first adhesive layer 37dA, and the second foam sheet 37B has the second adhesive layer 37dB. In the present embodiment, the first adhesive layer 37dA and the second adhesive layer 37dB are preferably different in type from each other. In this case, an adhesive layer having high adhesion to the magnet 36 can be selected as the first adhesive layer 37dA, and an adhesive layer having high adhesion to the rotor core 32 can be selected as the second adhesive layer 37dB. As a result, the magnet 36 can be more firmly fixed to the rotor core 32 by the first foam sheet 37A and the second foam sheet 37B.

The adhesion area between the foam sheet 37 and the magnet 36 or the adhesion area between the foam sheet 37 and the inner wall of the magnet hole 38 changes due to the change in the area of the foam sheet 37, and the adhesion force also changes accordingly. Therefore, the magnet holding force may vary due to the changing area of the foam sheet 37. The first foam sheet 37A and the second foam sheet 37B may also be made different in area from each other and different in magnet holding force from each other.

< modification >

Next, a modification example that can be adopted in the above embodiment will be described. In the description of each modification described below, the same reference numerals are given to the same components as those of the embodiment or modification described above, and the description thereof is omitted.

Modification 1

In comparison with the above-described embodiment, the rotor 130 of the first modification shown in fig. 5 is mainly different in the arrangement of the foam sheet 137.

As in the above embodiment, the rotor 130 of the present modification example includes the rotor core 32, the plurality of magnets 36, and the plurality of foam pieces 137.

The plurality of foam sheets 137 includes a first foam sheet 137A and a second foam sheet 137B. That is, the rotor 130 has a first foam sheet 137A and a second foam sheet 137B. The combination of the first foam piece 137A and the second foam piece 137B is accommodated in one magnet hole 38.

The first foam piece 137A and the second foam piece 137B are disposed between the inner wall of the magnet hole 38 and the magnet 36. The first foam piece 137A is disposed between the first wall surface 38a of the magnet hole 38 and the first long side surface 36a of the magnet 36 when viewed in the axial direction. On the other hand, the second foamed sheet 137B is a joined sheet covering the first long side surface 36a, the second long side surface 36B, the first short side surface 36c, and the second short side surface 36d. The second foam piece 137B is arranged in a C-shape around the magnet 36 when viewed in the axial direction. A gap is provided between a pair of end portions 137Ba, 137Bb of the second foam sheet 137B as viewed in the axial direction. The end portions 137Ba, 137Bb of the second foam sheet 137B face each other at a portion disposed along the second long side surface 36B. That is, the first foam sheet 137A is disposed on the first long side surface 36a, and the second foam sheet 137B is disposed on the first long side surface 36a, the second long side surface 36B, the first short side surface 36c, and the second short side surface 36d.

The first foam sheet 137A and the second foam sheet 137B are laminated and arranged at a portion of the magnet 36 along the first long side surface 36a. On the other hand, only the second foam piece 137B is disposed along the second long side surface 36B, the first short side surface 36c, and the second short side surface 36d of the magnet 36. Accordingly, a lamination area a, which is an area in which both the first foam sheet 137A and the second foam sheet 137B are laminated, and a single sheet area B, which is an area in which only either one of the first foam sheet 137A and the second foam sheet 137B is arranged, are provided on the outer periphery of the magnet 36.

In the present modification, one of the two foam sheets 137 stacked on each other, which is disposed on the inner side (the magnet 36 side), is the first foam sheet 137A, and the other one, which is disposed on the outer side, is the second foam sheet 137B. The first foam sheet 137A is in contact with and bonded to the outer periphery of the magnet 36 in the lamination area a. The second foamed sheet 137B is in contact with and bonded to the inner wall of the magnet hole 38 in the lamination area a and the single sheet area B. The second foam sheet 137B is in contact with and bonded to the outer periphery of the magnet 36 in the lamination area a. Further, the first foam sheet 137A and the second foam sheet 137B are bonded in contact with each other at the lamination interface.

In the present modification, at least one of the type and thickness of the foamed part 37B and the type of the adhesive layer 37d shown in fig. 4 may be different for the first foamed sheet 137A and the second foamed sheet 137B. In this case, the magnet holding force of the first foam sheet 137A and the magnet holding force of the second foam sheet 137B are different from each other. Further, the first and

second foam pieces

137A and 137B may also differ in magnet holding force due to differences in area from each other.

With the rotation of the rotor 130, the magnet 36 is applied with centrifugal force toward the radial outside. Therefore, the foam sheet 137 disposed on the first long side surface 36a of the magnet 36 requires a large magnet holding force. According to this modification, the lamination area a is disposed on the first long side surface 36a of the magnet 36 facing radially outward, and the single sheet area B is disposed in the other part. According to this modification, by setting the portion where the magnet holding force needs to be improved as the lamination area a and the other portion as the single sheet area B, the magnet 36 can be fixed with a sufficient force, the amount of the foam sheet 137 used can be suppressed, and the entire rotor 130 can be manufactured at low cost.

Modification II

In comparison with the above-described embodiment, the rotor 230 of the second modification shown in fig. 6 is mainly different in the arrangement of the foam sheet 237.

As in the above embodiment, the rotor 230 of the present modification example includes the rotor core 32, the plurality of magnets 36, and the plurality of foam pieces 237.

The plurality of foam sheets 237 includes a first foam sheet 237A and a second foam sheet 237B. That is, the rotor 230 has a first foam sheet 237A and a second foam sheet 237B. The combination of the first and

second foam pieces

237A and 237B is accommodated in one magnet hole 38.

The first and

second foam pieces

237A and 237B are disposed between the inner wall of the magnet hole 38 and the magnet 36. The first foam sheet 237A is a sheet integrally connected to cover the first long side surface 36a, the second long side surface 36b, the first short side surface 36c, and the second short side surface 36d. The first foam piece 237A is arranged in a C-shape around the magnet 36 as seen in the axial direction. A gap is provided between the pair of end portions 237Aa, 237Ab of the first foam piece 237A as viewed in the axial direction. The end portions 237Aa, 237Ab of the first foam piece 237A face each other at a portion disposed along the second long side surface 36b. On the other hand, the second foam piece 237B is disposed between the first wall surface 38a of the magnet hole 38 and the first long side surface 36a of the magnet 36 when viewed from the axial direction. That is, the first foam sheet 237A is disposed on the first long side surface 36a, the second long side surface 36B, the first short side surface 36c, and the second short side surface 36d, and the second foam sheet 237B is disposed on the first long side surface 36a.

The first foam piece 237A and the second foam piece 237B are laminated and arranged at a portion of the magnet 36 along the first long side surface 36a. On the other hand, only the first foam piece 237A is disposed along the second long side surface 36b, the first short side surface 36c, and the second short side surface 36d of the magnet 36. Therefore, a lamination area a, which is an area where both the first foam sheet 237A and the second foam sheet 237B are laminated, and a single sheet area B, which is an area where only either one of the first foam sheet 237A and the second foam sheet 237B is arranged, are provided on the outer periphery of the magnet 36.

In the present modification, one of the two foam pieces 237 stacked on each other, which is disposed on the inner side (the magnet 36 side), is the first foam piece 237A, and the other one, which is disposed on the outer side, is the second foam piece 237B. The first foam sheet 237A is in contact with and bonded to the outer periphery of the magnet 36 in the lamination area a and the single sheet area B. The first foam piece 237A is in contact with and bonded to the inner wall of the magnet hole 38 in the single sheet region B. On the other hand, the second foam piece 237B is in contact with and bonded to the inner wall of the magnet hole 38 in the lamination area a. Further, the first foam sheet 237A and the second foam sheet 237B are bonded in contact with each other at the lamination interface.

In the present modification, at least one of the type and thickness of the foamed part 37B and the type of the adhesive layer 37d shown in fig. 4 may be different for the first foamed sheet 237A and the second foamed sheet 237B. In this case, the magnet holding force of the first foam piece 237A and the magnet holding force of the second foam piece 237B are different from each other. Further, the first and

second foam pieces

237A and 237B may also differ in magnet holding force due to differences in area from each other.

According to the present modification, as in the modification described above, by setting the portion where the magnet holding force needs to be improved as the lamination area a and the other portion as the single sheet area B, the magnet 36 can be fixed with a sufficient force, the amount of the foam sheet 237 used can be suppressed, and the entire rotor 230 can be manufactured at low cost.

Modification III

In comparison with the above-described embodiment, the rotor 330 of the third modification shown in fig. 7 is mainly different in the arrangement of the foam pieces 337.

As in the above-described embodiment, the rotor 330 of the present modification example includes a rotor core 332 provided with a magnet hole 338, a plurality of magnets 36, and a plurality of foam pieces 337.

The plurality of foam pieces 337 includes a first foam piece 337A and a second foam piece 337B. That is, the rotor 330 has a first foam piece 337A and a second foam piece 337B. The combination of the first foam piece 337A and the second foam piece 337B is accommodated in one magnet hole 338.

The first foam piece 337A and the second foam piece 337B are disposed between the inner wall of the magnet hole 338 and the magnet 36. The first foam piece 337A has four divided sheets covering the first long side surface 36a, the second long side surface 36b, the first short side surface 36c, and the second short side surface 36d of the magnet 36, respectively. Similarly, the second foam piece 337B has four divided sheets that cover the first long side surface 36a, the second long side surface 36B, the first short side surface 36c, and the second short side surface 36 of the magnet 36 via the first foam piece 337A.

According to this modification, the first foam piece 337A and the second foam piece 337B are laminated and arranged in all gaps between the magnet 36 and the inner wall of the magnet hole 338. According to this modification, even when a force in an arbitrary direction acts on the magnet 36, the magnet 36 can be firmly held in the magnet hole 338. Further, by the cushioning effect of the foam portions 37B of the first foam piece 337A and the second foam piece 337B, even when the magnet 36 applies an impact force in an arbitrary direction, the magnet 36 can be prevented from being damaged. That is, according to this modification, the effect of laminating two foam pieces 337 on the entire magnet 36 can be obtained.

The rotary electric machine to which the present invention is applied is not limited to the motor, but may be a generator. The use of the rotary electric machine is not particularly limited. For example, the rotating electric machine may be mounted on the vehicle for a purpose other than the purpose of rotating the axle 64, or may be mounted on a device other than the vehicle. The posture when the rotating electric machine is used is not particularly limited.

In the above embodiment and the modification examples, the case where the magnets arranged in one magnet hole are held by a plurality of foam pieces was described. However, the same structure can be adopted for a rotor having a magnetic pole in which magnets are arranged in a V-shape when viewed from the axial direction.

For example, in the above embodiment and the modification thereof, the foam sheet is disposed on each of four faces (two long side faces and two short side faces) of the magnet facing the inner wall of the magnet hole when viewed from the axial direction. However, the foam sheet may be disposed with at least a part of the outer circumference of the magnet and the inner wall of the magnet hole, and may be in contact with the magnet and the inner wall of the magnet hole through a part.

In addition, when viewed from the axial direction, no gap may be provided between the pair of end portions 37Ba, 37Bb, 137Ba, 137Bb of the second foam sheet 37B. The end portions 37Ba, 37Bb, 137Ba, 137Bb of the second foam sheet 37B may also be in contact with each other at portions thereof disposed along the second long side surface 36B. Further, a gap may not be provided between the pair of end portions 37Ba, 37Bb, 137Ba, 137Bb of the second foam sheet 37B, and one end portion of the pair of end portions of the second foam sheet 37B may be located inside (on the magnet side of) the portion where the other end portion is located, and the second foam sheets may partially overlap each other.

When viewed from the axial direction, no gap may be provided between the pair of end portions 37Aa, 37Ab, 237Aa, 237Ab of the

first foam sheets

37A, 237A. The end portions 37Aa, 37Ab, 237Aa, 237Ab of the first foam sheet may be in contact with each other through a portion disposed along the second long side surface 36b. Further, a gap may not be provided between the pair of end portions 237Aa and 237Ab of the first foam sheet 237A, and one end portion of the pair of end portions 237Aa and 237Ab may be located inside (on the magnet side) of the portion where the other end portion is located.

Preferably, at least one of the first foam sheet or the second foam sheet covers a corner of the magnet. That is, the first foam sheet preferably covers at least one of the first long side surface and the first short side surface, the first long side surface and the second short side surface, and the second long side surface and at least one of the first short side surface, the second long side surface and the second short side surface. In the same manner, the second foam sheet preferably covers at least one of the first long side surface and the first short side surface, the first long side surface and the second short side surface, and the second long side surface and at least one of the first short side surface, the second long side surface and the second short side surface. This can prevent the corner of the rectangular parallelepiped magnet from being damaged by contact with the inner wall of the magnet.

In the magnet hole, at least one of the first foam sheet and the second foam sheet may be laminated in plurality with respect to the magnet.

While the embodiments and modifications of the present invention have been described above, the structures and combinations thereof in the embodiments and modifications are examples, and the structures may be added, omitted, replaced, and changed without departing from the scope of the present invention. The present invention is not limited to the embodiments.

Claims

1. A rotor, comprising:

the rotor comprises a rotor core body, wherein the rotor core body is provided with a magnet hole, and the magnet hole axially extends by taking a central axis as a center and penetrates through the center;

a magnet disposed in the magnet hole; and

a first foam sheet and a second foam sheet, the first foam sheet and the second foam sheet being disposed between the inner wall of the magnet hole and the magnet,

a lamination region is provided on at least a part of the outer periphery of the magnet, and the lamination region is used for laminating the first foam sheet and the second foam sheet.

2. The rotor of claim 1, wherein the rotor comprises a plurality of rotor blades,

the magnet has a rectangular shape when viewed in the axial direction, and has a first long side surface and a second long side surface which form long sides when viewed in the axial direction, and a first short side surface and a second short side surface which form short sides,

the first foam sheet is an integrally joined sheet covering the first long side surface, the second long side surface, the first short side surface, and the second short side surface,

the second foam sheet is a sheet integrally joined to cover the first long side surface, the second long side surface, the first short side surface, and the second short side surface with the first foam sheet interposed therebetween.

3. A rotor according to claim 2, wherein,

the end portions of the first foam sheet face each other at a portion disposed along the first long side surface, and the end portions of the second foam sheet face each other at a portion disposed along the second long side surface, as viewed in the axial direction.

4. The rotor of claim 1, wherein the rotor comprises a plurality of rotor blades,

a single sheet region is provided on the outer periphery of the magnet, and the single sheet region is configured only by any one of the first foam sheet and the second foam sheet.

5. The rotor of claim 1, wherein the rotor comprises a plurality of rotor blades,

the first foam sheet has four divided sheets covering a first long side surface, a second long side surface, a first short side surface, and a second short side surface,

the second foam sheet has four divided sheets covering a first long side surface, a second long side surface, a first short side surface, and a second short side surface with the first foam sheet interposed therebetween.

6. The rotor according to claim 1 to 5,

the magnet holding force of the first foam sheet and the magnet holding force of the second foam sheet are different from each other.

7. The rotor according to claim 1 to 6,

the first foam sheet has a first adhesive layer adhered to a surface of the magnet,

the second foam sheet has a second adhesive layer adhered to the inner wall of the magnet hole,

the first adhesive layer and the second adhesive layer are different from each other in kind.

8. A rotating electrical machine, characterized by comprising:

the motor of any one of claims 1 to 7; and

and a stator disposed radially outward of the rotor.

9. A driving device, characterized by comprising:

the rotary electric machine of claim 8; and

and the transmission device is connected with the rotor.