CN111756180B

CN111756180B - Motor

Info

Publication number: CN111756180B
Application number: CN202010085995.1A
Authority: CN
Inventors: 竹本心路; 松田和敏; 梶川哲
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2019-03-28
Filing date: 2020-02-11
Publication date: 2022-12-06
Anticipated expiration: 2040-02-11
Also published as: JP2020167780A; JP7302231B2; CN111756180A

Abstract

One embodiment of the present invention is a motor including: a rotor rotatable about a central axis; and a stator having a plurality of coils, the stator facing the rotor with a gap therebetween. In one embodiment of the present invention, the motor is provided with a sealed chamber in which a plurality of coils are housed. At least a part of the rotor is exposed to the inside of the closed chamber. The sealed chamber contains a refrigerant liquid.

Description

Motor

Technical Field

The present invention relates to a motor.

Background

Motors having a closed chamber for housing a coil are known. As such a motor, for example, patent document 1 describes an in-wheel motor.

Patent document 1: japanese patent laid-open publication No. 2017-185975

In the motor as described above, it is difficult to radiate heat of the coil to the outside of the sealed chamber. Therefore, further improvement in heat dissipation of the coil is required.

Disclosure of Invention

In view of the above, an object of the present invention is to provide a motor having a structure capable of improving heat dissipation of a coil.

One embodiment of the present invention is a motor including: a rotor rotatable about a central axis; and a stator having a plurality of coils, the stator facing the rotor with a gap therebetween. In one aspect of the present invention, the motor is provided with a sealed chamber in which the plurality of coils are housed. At least a part of the rotor is exposed to the inside of the closed chamber. A refrigerant liquid is contained in the closed chamber.

According to one aspect of the present invention, in the motor, heat dissipation of the coil can be improved.

Drawings

Fig. 1 is a sectional view showing a motor of embodiment 1.

Fig. 2 is a sectional view showing the motor of embodiment 1, and is a sectional view taken along line II-II of fig. 1.

Fig. 3 is a sectional view showing the motor of embodiment 2.

Fig. 4 is a sectional view showing a part of a motor according to a modification of embodiment 2.

Description of the reference symbols

10. 110: a motor; 20: a rotor; 22: a rotor magnet; 30. 130, 130: a stator; 31: a fixed shaft; 31a, 231a: a pull-out hole portion; 31d, 231d: an opening part; 33. 133: a stator core; 33a: a receiving hole part; 34. 134: the back of the iron core; 34a: an inner iron core portion; 34b: an outer iron core portion; 35: teeth; 37: a coil; 40: a cover; 43: a closed chamber; 61: a circuit board; 62: wiring; 70: an elastic member; 90: a refrigerant liquid; 90a: a liquid level; 134e: an extension portion; 134f: 1 st extension (extension); 134g: 2 nd extension (extension); 134h: the 3 rd extension (extension); j: a central axis.

Detailed Description

The Z-axis direction shown in the drawings is a vertical direction. The X-axis direction and the Y-axis direction are horizontal directions perpendicular to the Z-axis direction, and are directions perpendicular to each other. In the following embodiments, the X-axis direction is the left-right direction of a vehicle on which the motor is mounted. In the following embodiments, the Y-axis direction is the front-rear direction of a vehicle on which the motor is mounted.

A central axis J appropriately shown in each drawing is an imaginary line extending in a horizontal direction parallel to an X-axis direction which is a left-right direction. In the following description, a direction parallel to the axial direction of the center axis J is simply referred to as an "axial direction", a positive side in the axial direction X is referred to as a "right side", and a negative side in the axial direction X is referred to as a "left side". The radial direction centered on the central axis J is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J is simply referred to as the "circumferential direction". In addition, the positive side in the Z-axis direction (i.e., the upper side in the vertical direction) is simply referred to as "upper side", and the negative side in the Z-axis direction (i.e., the lower side in the vertical direction) is simply referred to as "lower side".

The vertical direction, the upper side, the lower side, the horizontal direction, the left-right direction, the left side, and the right side are only names for explaining the relative positional relationship of the respective portions, and the actual positional relationship and the like may be other positional relationships than the positional relationship and the like indicated by these names.

< embodiment 1 >

A motor 10 of the present embodiment shown in fig. 1 and 2 is mounted on a vehicle. The motor 10 is, for example, an in-wheel motor that rotates a wheel of a vehicle. The motor 10 is fixed to the chassis of the vehicle. Although not shown, the chassis of the vehicle is located on the left side of the motor 10.

As shown in fig. 1 and 2, in the present embodiment, the motor 10 is an outer rotor type motor. The motor 10 has: a rotor 20 rotatable about a central axis J; a stator 30 facing the rotor 20 with a gap therebetween;

bearings

51 and 52 rotatably supporting the rotor 20; a control unit 60 electrically connected to the stator 30; and an elastic member 70.

As shown in fig. 1, the stator 30 has a fixed shaft 31, a bush 32, a stator core 33, an insulator 36, and a plurality of coils 37. The fixed shaft 31 is disposed along the central axis J. In the present embodiment, the fixed shaft 31 has a cylindrical shape extending in the axial direction around the central axis J. The left end of the fixed shaft 31 protrudes to the left of a cover 40 described later. The right end of the fixed shaft 31 is covered from the right side by a cover 40 described later.

The fixed shaft 31 has a pull-out hole portion 31a. The drawing hole 31a extends from the inside to the outside of a sealed chamber 43 described later. In the present embodiment, the pull-out hole portion 31a has the 1 st portion 31b and the 2 nd portion 31c. The 1 st part 31b extends rightward from the left end surface of the fixed shaft 31. The end of the right side of the 1 st part 31b is located at the part of the fixed shaft 31 where the bearing 52 is fixed. The 2 nd portion 31c extends radially outward from the end on the right side of the 1 st portion 31 b. More specifically, the 2 nd portion 31c extends obliquely rightward and leftward from the end portion on the right side of the 1 st portion 31 b. The radially outer end of the 2 nd portion 31c is an opening 31d of the drawing hole 31a that opens into a sealed chamber 43 described later. In the present embodiment, the opening 31d faces upward.

The bush 32 has a cylindrical shape extending in the axial direction. In the present embodiment, the bush 32 has a cylindrical shape that is open to both sides in the axial direction around the central axis J. The bush 32 is fixed to the outer peripheral surface of the fixed shaft 31. The bush 32 is fixed to the fixed shaft 31 by press fitting, for example. As shown in fig. 1 and 2, the bush 32 has a recessed portion 32a recessed radially inward from the outer peripheral surface of the bush 32. In the present embodiment, the recessed portion 32a is recessed downward from an upper portion in the outer peripheral surface of the bush 32. The recess 32a extends in the axial direction and is open at both axial ends of the bush 32.

The stator core 33 is directly or indirectly fixed to the fixed shaft 31. In the present embodiment, the stator core 33 is indirectly fixed to the fixed shaft 31 via the bush 32. Although not shown, for example, a plurality of electromagnetic steel plates are stacked in the axial direction to form the stator core 33. As shown in fig. 2, the stator core 33 has a core back 34 and a plurality of teeth 35.

The core back 34 is an annular portion fixed directly or indirectly to the fixed shaft 31. In the present embodiment, the core back 34 is indirectly fixed to the fixed shaft 31 via the bush 32. In the present embodiment, the core back 34 is cylindrical and opens to both axial sides about the central axis J. The core back 34 includes an inner core portion 34a, an outer core portion 34b, and a coupling portion 34c.

The inner core portion 34a is annular and surrounds the bush 32 radially outward. In the present embodiment, the inner core portion 34a is cylindrical and opens to both sides in the axial direction around the central axis J. The inner core portion 34a is fixed to the outer peripheral surface of the fixed shaft 31 via the bush 32. The inner core portion 34a has a projection 34d projecting radially inward on the inner peripheral surface. The convex portion 34d is fitted to the concave portion 32a. This can suppress the relative rotation of the inner core portion 34a with respect to the bush 32 in the circumferential direction.

The outer core portion 34b is located at a position radially outward from the inner core portion 34 a. The outer core portion 34b is annular surrounding the inner core portion 34 a. In the present embodiment, the outer core portion 34b has a cylindrical shape that is open on both sides in the axial direction about the central axis J.

The coupling portion 34c connects the inner iron core portion 34a with the outer iron core portion 34 b. The coupling portion 34c extends radially from the outer peripheral surface of the inner core portion 34a to the inner peripheral surface of the outer core portion 34 b. In the present embodiment, a plurality of coupling portions 34c are provided. The plurality of coupling portions 34c are arranged at equal intervals in the circumferential direction over the entire circumference. For example, 8 coupling portions 34c are provided.

The plurality of teeth 35 extend radially outward from the core back 34. In the present embodiment, the plurality of teeth 35 extend radially outward from the outer peripheral surface of the core back 34. The plurality of teeth 35 are arranged at equal intervals over the entire circumference in the circumferential direction. For example 24 teeth 35.

Stator core 33 has a housing hole 33a. In the present embodiment, the storage hole portions 33a are located between the coupling portions 34c adjacent in the circumferential direction. The receiving hole 33a is surrounded by a pair of coupling portions 34c and outer core portions 34b adjacent to the inner core portions 34a in the circumferential direction. That is, in the present embodiment, the plurality of housing hole portions 33a are provided in the circumferential direction. In the present embodiment, the housing hole 33a penetrates the stator core 33 in the axial direction. The storage hole 33a has a fan shape when viewed in the axial direction, for example.

The insulators 36 are respectively attached to the plurality of teeth 35. As shown in fig. 1, the insulator 36 has a cylindrical portion 36a, an inner flange portion 36b, and an outer flange portion 36c. The cylindrical portion 36a is cylindrical and opens to both sides in the radial direction. The teeth 35 pass through the inside of the cylindrical portion 36a. The inner flange 36b extends from the radially inner end of the cylindrical portion 36a to the outside of the cylindrical portion 36a. The inner flange 36b protrudes axially on both sides of the cylindrical portion 36a. The outer flange portion 36c extends outward from the radially outer end of the cylindrical portion 36a toward the outside of the cylindrical portion 36a. The outer flange 36c protrudes axially on both sides of the cylindrical portion 36a.

The plurality of coils 37 are attached to the stator core 33. In the present embodiment, the plurality of coils 37 are attached to the plurality of teeth 35 via the insulating material 36. In the present embodiment, the coil 37 is wound around the cylindrical portion 36a. For example 24 coils 37 are provided.

The

bearings

51 and 52 rotatably support the rotor 20. In the present embodiment, the

bearings

51 and 52 are rolling bearings. The

bearings

51 and 52 are, for example, ball bearings. The inner rings of the

bearings

51 and 52 are fitted and fixed to the fixed shaft 31.

Rotor 20 includes cover 40, rotor core 21, and rotor magnet 22. The cover 40 houses the rotor core 21, the rotor magnet 22, the stator 30, the control unit 60, and the elastic member 70 therein. In the present embodiment, the cover 40 constitutes a housing of the motor 10. The cover 40 has a cover main body 41 and a cover member 42.

The cover main body 41 has a cylindrical shape with an opening to the left. In the present embodiment, the cover main body 41 has a cylindrical shape centered on the central axis J. The cover main body 41 has a side wall portion 41a, a peripheral wall portion 41b, and a bearing holding portion 41c.

The side wall portion 41a is located on the right side of the stator 30. The side wall portion 41a covers the stator 30 from the right side. In the present embodiment, the side wall portion 41a has a disc shape centered on the central axis J. The peripheral wall portion 41b has a cylindrical shape extending leftward from the radially outer peripheral edge portion of the side wall portion 41 a. The circumferential wall portion 41b surrounds the stator 30 radially outward of the stator 30. The bearing holding portion 41c has a cylindrical shape protruding leftward from the radially central portion of the side wall portion 41 a. In the present embodiment, the bearing holding portion 41c has a cylindrical shape that is open to the left about the central axis J. A bearing 51 is held radially inward of the bearing holding portion 41c.

The cover member 42 is fixed to the left side of the cover main body 41. The cover member 42 closes the opening on the left side of the cover main body 41. The cap member 42 includes a cap member body 42a, a seal tube portion 42b, and a bearing holding portion 42c. The cover member main body 42a is located on the left side of the stator 30. The cover member main body 42ac covers the stator 30 from the left side. The lid member main body 42a is annular with the center axis J as the center. The cover member main body 42a has a plate shape with a plate surface facing in the axial direction. The radially outer peripheral edge portion of the cap member body 42a contacts the left end portion of the peripheral wall portion 41 b.

The seal cylinder portion 42b is in a cylindrical shape protruding rightward from the radial outer peripheral edge portion of the cover member main body 42 a. In the present embodiment, the seal cylinder portion 42b has a cylindrical shape that is open to the right about the center axis J. The outer peripheral surface of the seal tube portion 42b is located radially inward of the radially outer peripheral end of the cap member body 42 a. The seal cylinder portion 42b is inserted into the peripheral wall portion 41b from the left side. The right end of the seal cylinder portion 42b axially faces the rotor core 21. An O-ring 81 is provided between the outer peripheral surface of the seal tube portion 42b and the inner peripheral surface of the peripheral wall portion 41 b. The O-ring 81 seals between the outer peripheral surface of the seal cylinder portion 42b and the inner peripheral surface of the peripheral wall portion 41 b.

The bearing holding portion 42c is provided at a radially inner peripheral edge portion of the lid member main body 42 a. The bearing holding portion 42c is cylindrical and opens to both sides in the axial direction around the center axis J. The left end of the bearing holding portion 42c protrudes leftward from the cover member main body 42 a. A bearing 52 is held radially inward of the bearing holding portion 42c. An O-ring 82 is provided between the inner peripheral surface of the bearing holding portion 42c and the outer peripheral surface of the outer ring of the bearing 52. The O-ring 82 seals between the inner peripheral surface of the bearing holding portion 42c and the outer peripheral surface of the outer ring of the bearing 52.

In the present embodiment, the inside of the cover 40 is sealed by sealing the space between the cover main body 41 and the lid member 42 with the O-

rings

81 and 82. That is, in the present embodiment, the cover 40 constitutes a sealed chamber 43. The closed chamber 43 accommodates the plurality of coils 37 therein. More specifically, in the present embodiment, the sealed chamber 43 accommodates the rotor core 21, the rotor magnet 22, the stator 30, the control unit 60, and the elastic member 70 therein. At least a part of the rotor 20 is exposed to the inside of the closed chamber 43. In the present embodiment, since the cover 40 constitutes the closed chamber 43, the inner surface of the cover 40 is exposed to the inside of the closed chamber 43. Further, rotor core 21 and rotor magnet 22 housed in cover 40 are also exposed to the inside of sealed chamber 43.

The sealed chamber 43 contains a refrigerant liquid 90. Therefore, by bringing the refrigerant liquid 90 into contact with the coil 37 housed in the sealed chamber 43, the heat of the coil 37 can be released to the refrigerant liquid 90. Thereby, the coil 37 is cooled. The heat released to the refrigerant liquid 90 is transferred from the refrigerant liquid 90 to the inner wall portion of the cover 40, and is released from the cover 40 to the outside of the motor 10. Here, since at least a part of the rotor 20 is exposed to the inside of the closed chamber 43, the rotor 20 rotates to stir the refrigerant liquid 90 contained in the inside of the closed chamber 43. This facilitates heat transfer from the refrigerant liquid 90 to the inner wall portion of the sealed chamber 43, that is, the inner wall portion of the cover 40. Therefore, the heat of the coil 37 can be appropriately released from the cover 40 to the outside of the motor 10 via the refrigerant liquid 90. As described above, according to the present embodiment, the heat dissipation of the coil 37 can be improved in the motor 10.

Further, since the heat released to the refrigerant liquid 90 is easily released to the outside of the sealed chamber 43, the temperature of the refrigerant liquid 90 raised by the heat of the release coil 37 can be appropriately lowered. This allows the refrigerant liquid 90 to efficiently cool the coil 37 without separately providing a cooling mechanism for cooling the refrigerant liquid 90. Therefore, the cooling efficiency of the coil 37 can be improved.

In addition, in the outer rotor type motor like the motor 10 of the present embodiment, when a closed chamber is provided, a heat transfer path from the stator core to the outer case of the motor is easily narrowed as compared with the inner rotor type motor. Therefore, in the outer rotor type motor, there is a problem that it is difficult to release heat of the coil to the outside. In contrast, according to the present embodiment, as described above, the heat of coil 37 can be easily transferred to cover 40 as an outer case via refrigerant liquid 90, and the heat radiation performance of coil 37 can be improved. As described above, when the motor 10 is an outer rotor type motor, the effect of improving the heat radiation performance of the coil 37 is particularly obtained.

Further, by forming the closed chamber 43 by the cover 40 of the rotor 20 as in the present embodiment, the closed chamber 43 can be rotated as a whole. Therefore, the refrigerant liquid 90 stored inside can be stirred more easily, and the heat of the coil 37 released to the refrigerant liquid 90 can be transmitted to the cover 40 more easily.

As an outer rotor type motor provided with a sealed chamber, for example, like the motor 10 of the present embodiment, an in-wheel motor that rotates a wheel of a vehicle can be cited. In-wheel motors are often used outdoors, and particularly, the sealing of a sealed chamber is often required. Therefore, heat is likely to be accumulated in the motor, and it is required to improve heat dissipation of the coil. That is, when the motor is an in-wheel motor, the heat radiation of the coil 37 can be improved.

As shown in fig. 2, in the present embodiment, the refrigerant liquid 90 is filled in the entire inside of the closed chamber 43. Therefore, the entire plurality of coils 37 can be immersed in the refrigerant liquid 90. This makes it easier to release the heat of coil 37 to refrigerant liquid 90, and to transfer the heat released to refrigerant liquid 90 to cover 40. Therefore, the heat dissipation of the coil 37 can be further improved. Since no gap is provided in the inside of the closed chamber 43, no liquid surface is generated in the closed chamber 43 as a boundary between the gap and the refrigerant liquid 90. Therefore, even if the refrigerant liquid 90 shakes in the sealed chamber 43, the liquid surfaces of the refrigerant liquid 90 do not collide with each other. This can suppress noise from the motor 10 generated by the refrigerant liquid 90.

In the present embodiment, the refrigerant liquid 90 is a liquid having an insulating property. Therefore, the number of steps for insulating and protecting the components of the motor 10 housed in the sealed chamber 43, through which current flows, can be reduced. In the present embodiment, the components of the motor 10 housed in the sealed chamber 43, through which current flows, include the plurality of coils 37 and the control unit 60. The refrigerant liquid 90 is, for example, a fluorine-based inert liquid.

The rotor core 21 is fixed to the cover 40. The rotor core 21 is annular and surrounds the stator 30 radially outside the stator 30. In the present embodiment, the rotor core 21 is cylindrical and opens to both axial sides about the central axis J. The outer peripheral surface of rotor core 21 is fixed to the inner peripheral surface of peripheral wall 41 b. Although not shown, for example, a plurality of electromagnetic steel plates are stacked in the axial direction to form the rotor core 21.

As shown in fig. 1, the rotor magnet 22 extends in the axial direction and has a plate shape with a plate surface facing in the radial direction. The rotor magnet 22 is directly or indirectly fixed to the radially inner side surface of the cover 40. In the present embodiment, rotor magnet 22 is fixed to the inner circumferential surface of rotor core 21. That is, the rotor magnet 22 is indirectly fixed to the inner peripheral surface of the peripheral wall 41b via the rotor core 21. The rotor magnet 22 is located radially outward of the stator 30. The rotor magnet 22 and the teeth 35 are radially opposed to each other with a gap therebetween.

As shown in fig. 2, in the present embodiment, a plurality of rotor magnets 22 are provided at intervals in the circumferential direction. The plurality of rotor magnets 22 are arranged at equal intervals in the circumferential direction over the entire circumference. For example, 28 rotor magnets 22 are provided.

As shown in fig. 1, the controller 60 is fixed to the stator 30. The control section 60 has a circuit board 61 and a wiring 62. That is, the motor 10 has a circuit board 61 and a wiring 62. The circuit board 61 has a plate shape with a plate surface facing in the axial direction. The circuit board 61 is housed inside the closed chamber 43. In the present embodiment, the circuit board 61 is fixed to the insulating member 36. The circuit board 61 is supported from the right side by the left end of the inner flange portion 36b and the left end of the outer flange portion 36c. In the present embodiment, the circuit board 61 is located above the fixed shaft 31. Although illustration is omitted, the circuit board 61 is directly or indirectly connected to a coil drawing line drawn from the coil 37. Thereby, the circuit board 61 is electrically connected to the stator 30.

The wiring 62 is connected to the circuit board 61. The wiring 62 extends from the circuit board 61 and passes through the pull-out hole portion 31a. The wiring 62 is drawn out from the inside of the closed chamber 43 to the outside through the drawing hole portion 31a. The gap between the wiring 62 and the pull-out hole 31a is filled and sealed with resin 83. This can suppress leakage of the refrigerant liquid 90 from the drawing hole 31a to the outside of the motor 10.

The elastic member 70 is made of an elastic body. The material of the elastic member 70 is not particularly limited as long as it is an elastomer, and may be polyurethane or an elastomer such as rubber. The elastic member 70 is housed inside the closed chamber 43. Therefore, even when the refrigerant liquid 90 filled in the entire inside of the closed chamber 43 is expanded by the heat from the coil 37, the elastic member 70 is elastically deformed by compression, and thus the pressure increase in the closed chamber 43 can be suppressed. This can suppress damage to the components of the motor 10 housed in the sealed chamber 43 when the refrigerant liquid 90 thermally expands.

In the present embodiment, the elastic member 70 is disposed inside the housing hole 33a provided in the stator core 33. Therefore, a space for separately housing the elastic member 70 in the sealed chamber 43 is not required, and an increase in size of the motor 10 can be suppressed. Further, by providing the stator core 33 with the housing hole 33a, the weight of the stator core 33 can be reduced, and weight reduction can be achieved. Therefore, the motor 10 can be reduced in weight.

As shown in fig. 1 and 2, in the present embodiment, the elastic members 70 are provided in the housing holes 33a, respectively. The elastic members 70 are fitted into the receiving holes 33a to fill the entire receiving holes 33a. In the present embodiment, the elastic member 70 is exposed at both axial sides thereof to the inside of the sealed chamber 43, and is in contact with the refrigerant liquid 90. Therefore, when the refrigerant liquid 90 thermally expands, the elastic member 70 receives pressure from both sides in the axial direction, and is compressively elastically deformed in the axial direction. As shown in fig. 2, the elastic member 70 has a fan shape when viewed in the axial direction, for example.

< embodiment 2 >

As shown in fig. 3, the refrigerant liquid 90 is contained in only a part of the sealed chamber 43 of the motor 110 according to the present embodiment. Therefore, as compared with the case where the refrigerant liquid 90 is filled in the entire inside of the closed chamber 43, even if the sealing performance of the cover 40 is lowered, the refrigerant liquid 90 is easily prevented from leaking from the inside to the outside of the closed chamber 43. This reduces the sealing performance of the cover 40 to such an extent that the refrigerant liquid 90 does not leak to the outside, thereby reducing the manufacturing cost of the cover 40. Therefore, the manufacturing cost of the motor 110 can be reduced.

Further, a space in which the refrigerant liquid 90 is not disposed can be provided in the closed chamber 43. Therefore, even if the elastic member 70 is not provided, the volume change due to the thermal expansion of the refrigerant liquid 90 can be absorbed by the air gap in the closed chamber 43. This can suppress a pressure increase in the sealed chamber 43. Therefore, the number of components of the motor 110 can be reduced in accordance with the elastic member 70 while suppressing damage to the components of the motor 110 housed in the sealed chamber 43.

In the present embodiment, the liquid surface 90a of the refrigerant liquid 90 stored in the closed chamber 43 is located below the center axis J. Therefore, the liquid surface 90a is easily arranged below the fixed shaft 31, and leakage of the refrigerant liquid 90 from between the fixed shaft 31 and the cover 40 can be further suppressed. Further, the refrigerant liquid 90 can be further suppressed from leaking to the outside from the pull-out hole 31a provided in the fixed shaft 31.

In the present embodiment, the liquid surface 90a of the refrigerant liquid 90 is located below the circuit board 61. Therefore, the circuit board 61 is not immersed in the refrigerant liquid 90. Therefore, the circuit board 61 can be prevented from being damaged by contact of the refrigerant liquid 90.

In particular, since the circuit board 61 has a high necessity of insulation, when the circuit board 61 is immersed in the refrigerant liquid 90, it is preferable to make the refrigerant liquid 90 have high insulation. However, generally, the higher the insulation (i.e., resistance) of the refrigerant liquid 90, the lower the thermal conductivity of the refrigerant liquid 90. Therefore, if the refrigerant liquid 90 having high insulation is used, the heat conductivity of the refrigerant liquid 90 is lowered, and there is a possibility that the heat radiation performance of the coil 37 is lowered. In contrast, according to the present embodiment, the circuit board 61 is not immersed in the coolant liquid 90, and thus the coolant liquid 90 having a low insulation property can be used. Therefore, the heat conductivity of the refrigerant liquid 90 can be easily increased. This enables the heat of the coil 37 to be more appropriately transmitted to the cover 40 by the refrigerant liquid 90. Therefore, the heat dissipation of the coil 37 can be further improved.

The relative positional relationship of the liquid surface of the refrigerant liquid described in the present specification may be satisfied in a state where the motor and the device mounted with the motor are still arranged on a horizontal plane in a state where the driving is stopped. That is, the relative positional relationship of the liquid surface 90a in the present embodiment may be satisfied in a state where the motor 110 and the vehicle on which the motor 110 is mounted are still arranged on a horizontal plane in a state where the driving is stopped. For example, the phrase "the liquid surface 90a is located below the circuit board 61" means that the liquid surface 90a is allowed to swing during driving of the motor 110 or the like, and a part of the liquid surface 90a is temporarily located at the same position in the axial direction as the circuit board 61 or located above the circuit board 61, as long as the above-described stationary arrangement state is satisfied.

In stator core 133 of stator 130 according to the present embodiment, core back 134 has a plurality of extending portions 134e extending in the vertical direction. The plurality of extensions 134e includes a 1 st extension 134f, a 2 nd extension 134g, and a 3 rd extension 134h. The 1 st extension 134f and the 2 nd extension 134g are extensions 134e that connect the inner iron core portion 34a with the outer iron core portion 34 b. That is, in the present embodiment, the inner core portion 34a and the outer core portion 34b are coupled by at least 1 extending portion 134e.

The 2 nd and 3

rd extensions

134g, 134h connect a portion on the lower side of the radially inner side face of the outer iron core portion 34b with a portion on the upper side of the radially inner side face of the outer iron core portion 34 b. That is, at least 1 of the plurality of extensions 134e connects a portion on the lower side of the radially inner side face of the outer core portion 34b with a portion on the upper side of the radially inner side face of the outer core portion 34 b. Therefore, the heat of the coil 37 positioned above the liquid surface 90a among the plurality of coils 37 is easily transferred to the lower side via the 2 nd extending portion 134g and the 3 rd extending portion 134h, and the heat is easily released into the refrigerant liquid 90 from the lower portion of the 2 nd extending portion 134g and the lower portion of the 3 rd extending portion 134h. Thus, even when the refrigerant liquid 90 is contained only in a part of the inside of the closed chamber 43, the heat of the plurality of coils 37 is easily released to the outside of the motor 110.

The 1 st extending portions 134f are provided in a pair sandwiching the inner core portion 34a in the vertical direction. Of the pair of 1 st extending portions 134f, the 1 st extending portion 134f located on the upper side is located above the liquid surface 90 a. The 1 st extending portion 134f located on the lower side of the pair of 1 st extending portions 134f is located on the lower side of the liquid surface 90a, and is immersed in the refrigerant liquid 90. Therefore, the heat transferred to the coil 37 of the inner core portion 34a via the 1 st extending portion 134f located on the upper side among the pair of 1 st extending portions 134f is easily released into the refrigerant liquid 90 via the 1 st extending portion 134f located on the upper side among the pair of 1 st extending portions 134 f.

The 2 nd extending portions 134g are provided in a pair across the inner core portion 34a in the vehicle front-rear direction (Y-axis direction). The center portion in the vertical direction of the 2 nd extending portion 134g is connected to both end portions in the front-rear direction of the inner core portion 34 a. The 3 rd extending portion 134h is provided in a pair sandwiching the pair of 2 nd extending portions 134g in the front-rear direction. The 3 rd extension 134h is not connected to the inner core portion 34 a. The lower end of the 2 nd extending portion 134g and the lower end of the 3 rd extending portion 134h are immersed in the refrigerant liquid 90. A gap or refrigerant liquid 90 is provided between the extending portions 134e. Unlike embodiment 1, stator core 133 is not provided with elastic member 70.

(modification of embodiment 2)

As shown in fig. 4, in the present modification, the pull-out hole 231a includes the 1 st portion 31b and the 2 nd portion 231c. The 2 nd portion 231c extends radially outward from the right end of the 1 st portion 31 b. More specifically, the 2 nd part 231c extends obliquely rightward and downward from the end on the right side of the 1 st part 31 b. The radially outer end of the 2 nd portion 231c is an opening 231d of the drawing hole 231a that opens into the sealed chamber 43. The opening 231d faces downward.

For example, if the resin 83 is not provided in the 2 nd portion of the drawing hole, if the opening of the drawing hole on the sealed chamber 43 side is directed upward, the splashed refrigerant liquid 90 may enter the inside of the 2 nd portion and be accumulated in the 2 nd portion. In this case, the refrigerant liquid 90 accumulated in the 2 nd portion may leak out of the sealed chamber 43 by seeping out from between the resin 83 and the wiring 62 or between the resin 83 and the inner surface of the pull-out hole portion.

In contrast, according to the present modification, the opening 231d of the pull-out hole 231a, which opens into the sealed chamber 43, faces downward. Therefore, even when the resin 83 is not provided in the 2 nd portion 231c, the refrigerant liquid 90 can be prevented from being accumulated in the 2 nd portion 231c. This can further suppress leakage of the refrigerant liquid 90 to the outside of the sealed chamber 43.

The present invention is not limited to the above-described embodiments, and the following configuration may be adopted. The sealed chamber is not particularly limited as long as it accommodates the plurality of coils and the refrigerant liquid therein and exposes at least a part of the rotor to the inside. For example, in an inner rotor type motor, the sealed chamber may be formed by a housing that holds the stator. In this case, the inside of the housing is a sealed chamber, and the portion of the rotor housed in the housing is exposed to the inside of the sealed chamber. In this case, the refrigerant liquid contained in the casing can be stirred by rotating the rotor inside the casing.

The refrigerant liquid is not particularly limited as long as the heat of the coil can be transferred to the inner wall portion of the sealed chamber. The refrigerant liquid may not have insulation. In this case, it is preferable that a member through which a current flows among the members disposed in the closed chamber is subjected to insulation protection having high insulation properties.

The housing hole provided in the stator core is not particularly limited as long as the elastic member can be housed in the housing hole. The receiving hole may be a hole having a bottom. The elastic member may not be disposed in the housing hole. The elastic member may be disposed to be movable in the closed chamber.

The type of motor is not particularly limited as long as it is a motor provided with a closed chamber that houses a plurality of coils. The motor may be an inner rotor type motor or an axial gap type motor. The use of the motor is not particularly limited. In addition, the respective structures described in the present specification can be appropriately combined within a range not inconsistent with each other.

Claims

1. A motor, comprising:

a rotor rotatable about a central axis; and

a stator having a plurality of coils, the stator facing the rotor with a gap therebetween,

the motor is provided with a closed chamber for accommodating the plurality of coils,

at least a part of the rotor is exposed to the inside of the closed chamber,

a refrigerant liquid is contained in the closed chamber,

the stator has:

a fixed shaft disposed along the central axis; and

a stator core directly or indirectly fixed to the fixed shaft, on which the coil is mounted,

the stator core has a plurality of receiving hole portions axially penetrating the stator core and circumferentially provided at intervals,

the motor further includes a plurality of elastic members housed in the sealed chamber, and the plurality of elastic members are disposed in the plurality of housing holes, respectively.

2. The motor of claim 1,

the rotor has:

a cover which constitutes the closed chamber and accommodates the stator therein; and

and a rotor magnet located radially outside the stator and directly or indirectly fixed to a radially inner surface of the cover.

3. The motor of claim 2,

the refrigerant liquid is filled in the whole inside of the closed chamber.

4. The motor of claim 2,

the refrigerant liquid is contained only in a part of the inside of the closed chamber.

5. The motor of claim 4,

the central axis extends in a horizontal direction,

the liquid surface of the refrigerant liquid is positioned below the center axis in the vertical direction.

6. The motor according to claim 4 or 5,

the motor also has a circuit board electrically connected to the stator,

the circuit board is received inside the closed chamber,

the liquid surface of the refrigerant liquid is positioned below the circuit board in the vertical direction.

7. The motor of claim 5,

the stator core has:

an annular core back fixed directly or indirectly to the fixed shaft; and

a plurality of teeth extending radially outward from the core back,

the iron core back has:

an inner iron core portion;

an annular outer core portion surrounding the inner core portion at a position radially outward of the inner core portion; and

a plurality of extending portions extending in a vertical direction,

the inner core portion and the outer core portion are joined by at least 1 of the extensions,

at least 1 of the plurality of extensions connects a vertically lower portion of the radially inner surface of the outer core portion to a vertically upper portion of the radially inner surface of the outer core portion.

8. The motor according to claim 4 or 5,

the motor also has wiring drawn from the inside to the outside of the closed chamber,

the fixed shaft has a pull-out hole portion extending from the inside to the outside of the closed chamber,

the pull-out hole portion is through which the wiring passes,

an opening of the draw-out hole portion that opens into the interior of the closed chamber faces downward in the vertical direction.

9. The motor according to any one of claims 1 to 5,

the refrigerant liquid is an insulating liquid.

10. The motor according to any one of claims 1 to 5,

the motor is an in-wheel motor that rotates a wheel of a vehicle.