WO2017056163A1

WO2017056163A1 - Electric motor

Info

Publication number: WO2017056163A1
Application number: PCT/JP2015/077370
Authority: WO
Inventors: 聖悟井口; 純基近藤; 晋太朗中野
Original assignee: 三菱電機株式会社
Priority date: 2015-09-28
Filing date: 2015-09-28
Publication date: 2017-04-06
Also published as: DE112015006790T5; TWI609559B; CN108141065A; JP5972502B1; KR20180032661A; KR101905370B1; TW201713013A; JPWO2017056163A1

Abstract

An electric motor 300 is provided with: a stator core 1; a rotor 200 disposed inside of the stator core 1; a cover 3a disposed on a stator core 1 end surface in the axis direction; a molded resin section 4a disposed between a plurality of coil ends 2a and the cover 3a; and a cylindrical housing 10, which is disposed on the radial outer side of the cover 3a, and which is disposed on the radial outer side of the stator core 1. Furthermore, the outer diameter of the cover 3a is smaller than the inner diameter of the housing 10, and the outer circumferential surface of the cover 3a is not in contact with the inner circumferential surface of the housing 10.

Description

Electric motor

The present invention relates to an electric motor including a stator and a rotor disposed inside the stator.

In recent years, there is an increasing demand for higher output and higher torque for electric motors for industrial use in order to cope with shortening of machining tact time. Along with the increase in output and torque of the electric motor, the amount of heat generated by the coils arranged on the stator increases. Therefore, it is necessary to efficiently exhaust the heat generated in the coil to the outside of the electric motor.

Patent Document 1 discloses a structure of an electric motor that efficiently discharges heat generated in a coil to the outside. The stator of the electric motor disclosed in Patent Document 1 includes an annular stator core, a plurality of coils spaced apart in the circumferential direction of the stator core, and a cylinder surrounding each coil end of the plurality of coils. A cover, a thermally conductive resin filled between the coil end and the cover, and a stator core and a housing disposed on the outer peripheral side of the cover. In the cover of Patent Document 1, the outer diameter of a partial region of the outer peripheral surface is the same as the outer diameter of the stator core.

Japanese Patent No. 5607708

When fitting the housing to the stator core by shrink fitting, the cover expands due to heat transferred from the housing to the cover. However, in the cover of Patent Document 1, the outer diameter of a partial region of the outer peripheral surface is the same as the outer diameter of the stator core. Therefore, in Patent Document 1, there is a possibility that the outer peripheral surface of the cover expanded by the heat transmitted from the housing contacts the inner peripheral surface of the housing, and the housing in the middle of fitting stops at an unintended position. Therefore, the stator of Patent Document 1 has a problem that the workability of fitting the housing into the stator core decreases.

The present invention has been made in view of the above, and an object of the present invention is to obtain an electric motor that improves the fitting workability of the housing while efficiently discharging the heat generated at the coil end to the outside.

In order to solve the above-described problems and achieve the object, an electric motor of the present invention is arranged in a circumferential direction of an annular stator core, a rotor disposed inside the stator core, and the stator core. A plurality of coils. The electric motor of the present invention includes a cylindrical cover that is disposed on an axial end surface of the stator core and surrounds coil ends of a plurality of coils protruding from the axial end surface of the stator core. In addition, the electric motor of the present invention has a thermally conductive resin portion disposed between each of the coil ends of the plurality of coils and the cover, and is disposed on the radially outer side of the cover and on the radially outer side of the stator core. And a cylindrical housing arranged. The outer diameter of the cover is smaller than the outer diameter of the stator core and smaller than the inner diameter of the housing, and the outer peripheral surface of the cover is not in contact with the inner peripheral surface of the housing.

The electric motor according to the present invention has an effect of improving the workability of fitting the housing while efficiently discharging the heat generated at the coil end to the outside.

The longitudinal cross-sectional view of the electric motor which concerns on Embodiment 1 of this invention 1 is a longitudinal sectional view of a stator of an electric motor according to Embodiment 1 of the present invention. III-III arrow sectional view shown in FIG. IV-IV arrow sectional view shown in FIG. Enlarged view of one end of the stator shown in FIG. The figure which shows the relationship between the clearance gap shown in FIG. 5, and the temperature of a coil end Sectional drawing of the stator of the electric motor which concerns on Embodiment 2 of this invention Sectional drawing of the stator of the electric motor which concerns on Embodiment 3 of this invention. Sectional drawing which shows the 1st modification of the stator which concerns on Embodiment 1-3 of this invention Sectional drawing which shows the 2nd modification of the stator which concerns on Embodiment 1-3 of this invention

Hereinafter, an electric motor according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view of an electric motor according to Embodiment 1 of the present invention. FIG. 2 is a longitudinal sectional view of the stator of the electric motor according to Embodiment 1 of the present invention. 3 is a cross-sectional view taken along arrow III-III shown in FIG. 4 is a cross-sectional view taken along the line IV-IV shown in FIG. 2 and 3, illustration of the rotor 200 shown in FIG. 1 is omitted. FIG. 5 is an enlarged view of one end side of the stator shown in FIG. Hereinafter, the configuration of the electric motor 300 according to Embodiment 1 will be described with reference to FIGS. 1 to 5.

The electric motor 300 according to the first embodiment includes a stator 100, a rotor 200 disposed on the inner side of the stator core 1 constituting the stator 100, and a cylindrical shape disposed on the radially outer side of the stator core 1. Housing 10.

The stator core 1 is formed by laminating a plurality of annular thin plates punched from electromagnetic steel sheets. The stator core 1 has a hollow hole 11 therein.

The stator core 1 has a plurality of slots 12 in the circumferential direction. A coil 2 is disposed in each of the plurality of slots 12.

Between the coil 2 arranged in each of the plurality of slots 12 and the inner peripheral surface of each of the plurality of slots 12, a mold resin portion 4 that is a heat conductive resin portion is filled. The material of the mold resin portion 4 is an epoxy resin or an unsaturated polyester resin.

The coil ends 2 a on one end side of each of the plurality of coils 2 protrude in the axial direction from one end face 1 a of the stator core 1. The axial direction indicates the direction in which the rotation center axis extends.

A cylindrical cover 3a surrounding a plurality of coil ends 2a is disposed on one end face 1a of the stator core 1.

The cover 3 a is attached to one end surface 1 a of the stator core 1. Specifically, a depression is formed in advance on one end surface 1a of the stator core, and a protrusion is formed on the end surface of the cover 3a. Then, the cover 3 a is attached by fitting the protrusion of the cover 3 a into the recess of the stator core 1. The cover 3a attached to the one end surface 1a of the stator core 1 is processed so that the outer diameter D2 is smaller than the outer diameter D1 of the stator core 1.

On one end side of the stator core 1, a mold resin portion 4a, which is a heat conductive resin portion covering each of the plurality of coil ends 2a, is formed. The material of the mold resin portion 4a is an unsaturated polyester resin.

Specifically, the mold resin portion 4a is formed between the outer side in the radial direction of the coil end 2a and the cover 3a. The mold resin portion 4a is formed on the inner side in the radial direction of the coil end 2a. Further, the mold resin portion 4a is formed on the tip end side in the axial direction of the coil end 2a.

The mold resin portion 4a is in close contact with the entire outer peripheral surface of each of the plurality of coil ends 2a, and in close contact with the entire inner peripheral surface of the cover 3a. The surface on the stator core 1 side of the mold resin portion 4 a is in contact with one end surface 1 a of the stator core 1.

The coil end 2b on the other end side of each of the plurality of coils 2 protrudes from the other end surface 1b of the stator core 1 in the axial direction.

A cylindrical cover 3b surrounding the plurality of coil ends 2b is disposed on the other end surface 1b of the stator core 1.

The cover 3 b is attached to the other end surface 1 b of the stator core 1. Specifically, a depression is formed in advance on the other end surface 1b of the stator core, and a protrusion is formed on the end surface of the cover 3b. Then, the cover 3 b is attached by fitting the protrusion of the cover 3 b into the recess of the stator core 1. The cover 3b attached to the other end surface 1b of the stator core 1 is processed so that the outer diameter D2 is smaller than the outer diameter D1 of the stator core 1.

On the other end side of the stator core 1, a mold resin portion 4b, which is a heat conductive resin portion covering each of the plurality of coil ends 2b, is formed. The material of the mold resin portion 4b is an unsaturated polyester resin.

Specifically, the mold resin portion 4b is formed between the outer side in the radial direction of the coil end 2b and the cover 3b. The mold resin portion 4b is formed on the radially inner side of the coil end 2b. The mold resin portion 4b is formed on the tip end side in the axial direction of the coil end 2b.

The mold resin portion 4b is in close contact with the entire outer peripheral surface of each of the plurality of coil ends 2b, and in close contact with the entire inner peripheral surface of the cover 3b. The surface on the stator core 1 side of the mold resin portion 4 b is in contact with the other end surface 1 b of the stator core 1.

The coil 2 is insulated and connected to the lead wire 20. Electric power is supplied to the coil 2 via the lead wire 20.

The rotor 200 includes a rotor core 5 formed by laminating a plurality of thin annular plates punched from electromagnetic steel sheets, and an aluminum conductor 6 disposed in the slot of the rotor core 5 and in the annular shape on the front end side in the axial direction. . The rotor 200 is disposed in the hollow hole 11 of the stator core 1 coaxially with the axis of the stator core 1.

The cylindrical housing 10 is arranged on the outer side in the radial direction of each of the two

covers

3 a and 3 b, and is arranged on the outer side in the radial direction of the stator core 1.

The inner diameter D3 of the housing 10 is equal to the outer diameter D1 of the stator core 1. The outer diameter of each of the

covers

3a and 3b is smaller than the inner diameter D3 of the housing 10. As described above, each of the

covers

3 a and 3 b has an outer diameter D 2 smaller than the outer diameter D 1 of the stator core 1.

Therefore, the stator 100 has a gap G between the outer peripheral surfaces of the

covers

3 a and 3 b and the inner peripheral surface of the housing 10. In the stator 100, the gap G is reliably formed between each of the

covers

3a and 3b and the housing 10. Therefore, the outer peripheral surfaces of the

covers

3 a and 3 b are not in contact with the inner peripheral surface of the housing 10.

When the housing 10 is fitted from the cover 3 a side by shrink fitting, the stator core 1 and the cover 3 a are expanded by the heat of the housing 10.

At this time, the outer diameters D1 and D2 of the stator core 1 and the cover 3a are enlarged. Therefore, even if the outer diameter D2 of the cover 3a is enlarged, the outer diameter D2 of the cover maintains a size smaller than the inner diameter D3 of the housing 10. Therefore, the gap G remains. Moreover, since the cover 3a does not contact the housing 10 due to the gap G, the heat absorption amount of the cover 3a is lower than the heat absorption amount of the stator core 1 with which the cover 3a contacts.

This makes it possible to prevent the housing 10 from stopping at an unintended position while the housing 10 is being fitted. As a result, the workability of fitting the housing 10 is improved, the working time for manufacturing the stator 100 is shortened, and the manufacturing cost of the stator 100 can be reduced.

FIG. 6 is a diagram showing the relationship between the gap shown in FIG. 5 and the coil end temperature. The horizontal axis represents the size of the gap between the cover and the housing, and the vertical axis represents the temperature of the coil end. In FIG. 6, when the gap G is 0 μm, the temperature of heat generated at the coil end is assumed to be 100 ° C., and the temperature at the coil end when the gap G changes from 0 μm to 500 μm is shown.

The temperature change amount of the coil end when the gap G is 0 μm to 100 μm is 2 ° C. or more, and the temperature change amount of the coil end when the gap G is 100 μm to 500 μm is less than 1 ° C. That is, the temperature change amount when the gap G is 0 μm to 100 μm is larger than the temperature change amount when the gap G is 100 μm to 500 μm. The heat generated at the coil end indicates that when the gap G is less than 100 μm, it is more effectively transmitted to the housing 10 than when the gap G is 100 μm or more. Accordingly, the gap G is desirably less than 100 μm.

In the first embodiment, the case where the housing 10 is fitted into the stator core 1 by shrink fitting has been described. However, the same effect can be obtained in the case of cold fitting. In the case of cold fitting, when the housing 10 is fitted into the stator core 1 cooled in advance, the cover 3a expands and its outer diameter D2 increases. However, even if the outer diameter D2 of the cover 3a is enlarged, the outer diameter D2 of the cover is kept smaller than the inner diameter D3 of the housing 10. Therefore, the gap G remains. Moreover, since the cover 3a does not contact the housing 10 due to the gap G, the heat absorption amount of the cover 3a is lower than the heat absorption amount of the stator core 1 with which the cover 3a contacts. Thereby, it is possible to prevent the housing 10 from stopping at an unintended position during the fitting of the housing 10. As a result, the workability of fitting the housing 10 is improved, the working time for manufacturing the stator 100 is shortened, and the manufacturing cost of the stator 100 can be reduced.

Embodiment 2. FIG.
FIG. 7 is a cross-sectional view of the stator of the electric motor according to Embodiment 2 of the present invention. FIG. 7 shows an enlarged view of one end side of the stator of the electric motor according to the second embodiment. An arrow shown in FIG. 7 represents a path through which heat generated in the coil end 2a is transmitted to the housing 10 when the coil end 2a is at a constant temperature during operation of the electric motor 300-1. A dotted line a1 represents the outline of the cover 3a-1 before the coil end 2a reaches a certain temperature. A solid line a2 represents the outline of the cover 3a-1 when the coil end 2a reaches a certain temperature. The gap G is a gap generated between the cover 3a-1 and the housing 10 before the coil end 2a reaches a certain temperature.

The stator according to the second embodiment includes a cover 3a-1 instead of the cover 3a according to the first embodiment. The cover 3a-1 is made of a material having a linear expansion coefficient larger than that of the stator core 1. The material of the cover 3a-1 is an aluminum alloy, an austenitic stainless alloy, a copper alloy, or a high thermal conductive resin.

A6063 used for extrusion as aluminum alloy, A5056 used for bar material, SUS303, SUS304 as austenitic stainless steel, chromium copper, beryllium copper as copper alloy, alumina filler and CTBN as high thermal conductive resin An example is an epoxy resin mixed with (Carboxy-Terminated Butadiene-Nitrile).

The outer diameter of the cover 3 a-1 when the electric motor 300-1 is in operation is the same size as the outer diameter of the stator core 1, and the same size as the inner diameter of the housing 10. Further, the outer peripheral surface of the cover 3 a-1 during operation of the electric motor 300-1 is in contact with the inner peripheral surface of the housing 10.

Hereinafter, the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted, and different parts are described here.

The heat generated in the coil end 2a during operation of the electric motor 300-1 is first transmitted to the mold resin portion 4a. The heat transferred to the mold resin portion 4a is transferred to the cover 3a-1. Part of the heat transferred to the cover 3a-1 is transferred to the stator core 1 through the contact surface between the cover 3a-1 and the stator core 1.

Both the stator core 1 and the cover 3a-1 expand due to the heat generated at the coil end 2a. Accordingly, the outer diameters D1 and D2 of the stator core 1 and the cover 3a-1 are enlarged.

As described above, the cover 3a-1 is made of a material having a linear expansion coefficient larger than that of the stator core 1. The outer peripheral surface of the cover 3a-1 before the coil end 2a reaches a certain temperature is not in contact with the inner peripheral surface of the housing 10, as indicated by a dotted line a1. However, the outer peripheral surface of the cover 3a-1 when the coil end 2a reaches a certain temperature is in contact with the inner peripheral surface of the housing 10, as indicated by a solid line a2.

The heat generated in the coil end 2a during operation of the electric motor 300-1 is first transmitted to the mold resin portion 4a. The heat transferred to the mold resin portion 4a is transferred to the cover 3a-1.

Part of the heat transferred to the cover 3a-1 is transferred to the stator core 1 via the contact surface between the cover 3a-1 and the stator core 1. The heat transmitted to the stator core 1 is transmitted from the outer peripheral surface of the stator core 1 to the housing 10 and is released from the surface of the housing 10.

Further, part of the heat transmitted to the cover 3 a-1 is transmitted to the housing 10 via the contact surface between the cover 3 a-1 and the housing 10. The heat transmitted to the housing 10 is released from the surface of the housing 10.

In the electric motor 300-1 of the second embodiment, the cover 3a-1 expands and contacts the housing 10. Therefore, the amount of heat transferred from the cover 3a-1 to the housing 10 is relatively increased. As a result, the amount of heat released from the housing 10 to the outside is improved, and the cooling efficiency of the coil end 2a is improved.

The cover 3b shown in FIGS. 1 and 2 may be made of the same material as the cover 3a-1 of the second embodiment. Thereby, the amount of heat transmitted from the cover 3b to the housing 10 is relatively increased, and the cooling efficiency of the coil end 2b is improved.

Embodiment 3 FIG.
FIG. 8 is a sectional view of the stator of the electric motor according to Embodiment 3 of the present invention. FIG. 8 is an enlarged view of one end side of the stator of the electric motor according to the third embodiment. An arrow shown in FIG. 8 represents a path through which heat generated in the coil end 2a is transmitted to the housing 10 when the coil end 2a is at a constant temperature during operation of the electric motor 300-2. A dotted line a3 represents the outline of the cover 3a-2 before the coil end 2a reaches a certain temperature. A solid line a4 represents the outline of the cover 3a-2 when the coil end 2a reaches a certain temperature. The gap G is a gap generated between the cover 3a-2 and the housing 10 before the coil end 2a reaches a certain temperature.

The stator of Embodiment 3 uses a cover 3a-2 instead of the cover 3a of Embodiment 1. The cover 3a-2 is made of a material having a linear expansion coefficient equal to or smaller than the linear expansion coefficient of the stator core 1. The material of the cover 3a-2 is cast iron, steel, or iron alloy.

Examples of cast iron include gray cast iron such as FC200, spheroidal graphite cast iron such as FCD400, steel as carbon steel such as SC450, carbon steel pipe material for mechanical structure such as STKM, and iron alloy such as chromium molybdenum steel such as SCM. .

The outer diameter of the cover 3 a-2 during operation of the electric motor 300-2 is smaller than the outer diameter of the stator core 1 and smaller than the inner diameter of the housing 10. Further, the outer peripheral surface of the cover 3 a-2 during operation of the electric motor 300-2 is not in contact with the inner peripheral surface of the housing 10.

The heat generated in the coil end 2a during operation of the electric motor 300-2 is first transmitted to the mold resin portion 4a. The heat transferred to the mold resin portion 4a is transferred to the cover 3a-2. Part of the heat transferred to the cover 3a-2 is transferred to the stator core 1 through the contact surface between the cover 3a-2 and the stator core 1.

Both the stator core 1 and the cover 3a-2 expand due to the heat generated at the coil end 2a. Accordingly, the outer diameters D1 and D2 of the stator core 1 and the cover 3a-2 are enlarged. However, the cover 3a-2 is made of a material having a linear expansion coefficient equal to or smaller than the linear expansion coefficient of the stator core 1. Therefore, even if the outer diameter D2 of the cover 3a-2 is enlarged, the outer diameter D2 of the cover maintains a dimension smaller than the inner diameter D3 of the housing 10.

Therefore, the outer peripheral surface of the cover 3a-2 before the coil end 2a reaches a certain temperature is not in contact with the inner peripheral surface of the housing 10, as indicated by a dotted line a3.

Further, the outer peripheral surface of the cover 3a-2 when the coil end 2a reaches a certain temperature is not in contact with the inner peripheral surface of the housing 10, as indicated by a solid line a4. At this time, since the cover 3a-2 does not come into contact with the housing 10, the compressive stress due to the interference between the cover 3a-2 and the housing 10 does not act on the mold resin portion 4a. Therefore, the occurrence of cracks in the mold resin portion 4a due to the action of compressive stress is suppressed. As a result, a part of the mold resin portion 4a is prevented from dropping into the electric motor, and the quality of the electric motor 300-2 is improved.

The heat transmitted to the stator core 1 is transmitted from the outer peripheral surface of the stator core 1 to the housing 10 and released from the surface of the housing 10.

Part of the heat transferred to the cover 3a-2 is released to the gap G between the outer peripheral surface of the cover 3a-2 and the housing 10. The heat released to the gap G is transmitted from the inner peripheral surface of the housing 10 to the housing 10 and is released from the surface of the housing 10.

In the electric motor 300-2 of the third embodiment, it is not necessary to use a material for preventing the occurrence of cracks in the mold resin portion 4a, that is, an expensive resin that can withstand compressive stress. As a result, the manufacturing cost of the stator can be reduced.

The cover 3b shown in FIGS. 1 and 2 may be made of the same material as the cover 3a-2 of the third embodiment. Thereby, the occurrence of cracks in the mold resin portion 4b is suppressed, and the quality of the electric motor 300-2 is improved.

In the first to third embodiments, the example in which the cover is processed so that the outer diameter of the cover is smaller than the outer diameter of the stator core 1 has been described. However, when processing the cover, the tip of the machine tool for processing the cover may come into contact with the stator core 1. When the tip of the machine tool comes into contact with the stator core 1, the processability of the cover is deteriorated, and it is difficult to ensure the dimensional accuracy of the cover. A modification of the stator for solving such a problem is shown in FIGS.

FIG. 9 is a cross-sectional view showing a first modification of the stator according to Embodiments 1 to 3 of the present invention. FIG. 9 is an enlarged view of one end side of the stator.

The stator shown in FIG. 9 includes a stator core 1-1 instead of the stator core 1 of the first to third embodiments. In the stator core 1-1, the outer diameter of the one end 1c on the cover 3a side is formed in advance so as to be equal to the outer diameter D2 of the cover 3a. The gap G is a gap generated between the cover 3a and the housing 10 after adjusting the outer diameter.

When the outer diameter of the cover 3a attached to the stator core 1-1 is adjusted by pre-processing the one end 1c of the stator core 1-1, the tip of the machine tool is one end of the stator core 1-1. It can prevent contacting 1c. As a result, the dimensional accuracy of the outer shape of the cover 3a is improved, and the fitting workability of the housing 10 is further improved.

The stator core 1-1 shown in FIG. 9 can be combined with the covers of the second and third embodiments. By combining the cover of the second and third embodiments with the stator core 1-1, in addition to the effects of the second and third embodiments, the effect of further improving the fitting workability of the housing 10 can be obtained.

FIG. 10 is a cross-sectional view showing a second modification of the stator according to Embodiments 1 to 3 of the present invention. FIG. 10 is an enlarged view of one end side of the stator.

The stator shown in FIG. 10 includes a cover 3a-3 instead of the

covers

3a, 3a-1, 3a-2 of the first to third embodiments. Further, the stator shown in FIG. 10 includes a stator core 1-2 instead of the stator core 1 of the first to third embodiments. The gap G is a gap generated between the cover 3a-3 and the housing 10 after adjusting the outer diameter.

In the cover 3a-3, the outer diameter of the first end portion 31 on the stator core 1-2 side is smaller than the outer diameter of the second end portion 32 on the opposite side to the stator core 1-2 side. It is assumed that the outer diameter of the first end portion 31 is formed in advance smaller than the outer diameter of the second end portion 32.

In the stator core 1-2, the outer diameter of the one end 41 on the cover 3a-3 side is equal to the outer diameter of the first end 31 of the cover 3a-3. It is assumed that the outer diameter of the one end portion 41 is formed in advance to be equal to the outer diameter of the first end portion 31.

By combining the stator core 1-2 and the cover 3a-3, a groove 50 is formed at the boundary between the cover 3a-3 and the stator core 1-2.

When adjusting the outer diameter of the cover 3a-3 attached to the stator core 1-2, the groove portion 50 can prevent the tip of the machine tool from coming into contact with the one end portion 41 of the stator core 1-2. As a result, the dimensional accuracy of the outer shape of the cover 3a-3 is improved, and the workability of fitting the housing 10 is further improved.

Further, the stator cores of the first to third embodiments are not limited to those obtained by laminating a plurality of electromagnetic steel sheets. The stator core may be an integral core obtained by processing a steel material into a cylindrical shape, a resin core obtained by solidifying a mixture of resin and iron powder, or a dust core obtained by pressing magnetic powder. The type of the stator core is properly used depending on the purpose and application.

Further, the cover of the first to third embodiments may be a mortar shape whose outer diameter is reduced from the rotor core side to the anti-rotor core side. This shape facilitates the operation of fitting the housing 10 to the stator core 1.

Further, the rotor 200 of the first to third embodiments may be a rotor for an induction motor or a rotor for a synchronous motor.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1,1-1,1-2 Stator core, 1a one end surface, 1b other end surface, 1c one end, 2 coils, 2a, 2b coil end, 3a, 3a-1, 3a-2, 3a-3,

3b cover

4, 4a, 4b, mold resin part, 5 rotor core, 6 aluminum conductor, 10 housing, 11 hollow hole, 12 slot, 20 lead wire, 31 first end, 32 second end, 41 one end , 50 grooves, 100 stators, 200 rotors, 300, 300-1, 300-2 electric motors.

Claims

An annular stator core,
A rotor disposed inside the stator core;
A plurality of coils arranged in a circumferential direction of the stator core;
A cylindrical cover disposed on the axial end surface of the stator core and surrounding the coil ends of the plurality of coils protruding from the axial end surface of the stator core;
A thermally conductive resin portion disposed between each of the coil ends of the plurality of coils and the cover;
A cylindrical housing disposed on the radially outer side of the cover and disposed on the radially outer side of the stator core; and
With
The outer diameter of the cover is smaller than the inner diameter of the housing,
The electric motor according to claim 1, wherein an outer peripheral surface of the cover is not in contact with an inner peripheral surface of the housing.
The cover is made of a material having a linear expansion coefficient larger than that of the stator core,
The outer diameter of the cover when the motor is in operation is equal to the inner diameter of the housing,
The electric motor according to claim 1, wherein an outer peripheral surface of the cover is in contact with an inner peripheral surface of the housing when the electric motor is in operation.
3. The electric motor according to claim 2, wherein the material of the cover is an aluminum alloy, an austenitic stainless alloy, a copper alloy, or a high thermal conductive resin.
The cover is made of a material having a linear expansion coefficient equal to or lower than the linear expansion coefficient of the stator core,
The outer diameter of the cover when the electric motor is in operation is smaller than the inner diameter of the housing,
2. The electric motor according to claim 1, wherein an outer peripheral surface of the cover when the electric motor is in operation is not in contact with an inner peripheral surface of the housing.
5. The electric motor according to claim 4, wherein the material of the cover is cast iron, steel, or iron alloy.