Motor

Abstract

To provide a motor capable of sufficiently dissipating the heat of a coil without damaging an insulating coating of a coil.SOLUTION: A motor includes a rotor rotatable about a central axis, and a stator which is radially opposed to the rotor with a gap therebetween. The stator includes a stator core 20 having an annular core back 21 surrounding the central axis, and teeth 22 extending radially inward from the core back, and a coil 30 wound around the teeth. The stator core has at least one hole HL that penetrates in the axial direction of the central axis, and a slit SL that is a space for connecting the hole and the outside of the stator core in the radial direction. The motor has a heat pipe 50 which is held in the hole and extends axially along the hole, and an adhesive filled between the hole and the heat pipe.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] In a motor, heat generated by a coil cannot be sufficiently dissipated through a motor housing or the like, and the upper limit of the motor output levels off due to the temperature rise of the coil caused by heat generation. Therefore, by reducing the thermal resistance, the output is increased with a motor of the same size.

[0003] Patent Document 1 discloses that heat generated by a coil is dissipated by disposing a heat pipe extending in the direction of the rotating shaft in a gap between a core back of a stator core and the coil.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the configuration disclosed in Patent Document 1, it is difficult to stably fix the heat pipe, so there is a possibility of damaging the insulating coating of the coil at the portion where the heat pipe contacts the coil. Further, in the configuration disclosed in Patent Document 1, it is difficult to sufficiently cool the region of the coil that protrudes from the stator core in the direction of the rotating shaft among the coils.

[0006] The present invention has been made in consideration of the above points, and an object thereof is to provide a motor that can sufficiently dissipate the heat of a coil without damaging the insulating coating of the coil.

Means for Solving the Problems

[0007] One aspect of the motor of the present invention includes a rotor rotatable about a central axis, and a stator radially opposed to the rotor with a gap therebetween. The stator includes a stator core having an annular core back surrounding the central axis and teeth extending radially inward from the core back, and a coil wound around the teeth. The stator core has at least one hole penetrating in the axial direction of the central axis and a slit which is a space connecting the hole and the radially outer side of the stator core. The stator core further has a heat pipe held in the hole and extending axially along the hole, and an adhesive filled between the hole and the heat pipe.

Advantages of the Invention

[0008] According to one aspect of the present invention, heat of the coil can be sufficiently dissipated without damaging the insulating coating of the coil in the motor.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, with reference to the drawings, a motor according to an embodiment of the present invention will be described. Note that the scope of the present invention is not limited to the following embodiments and can be arbitrarily changed within the scope of the technical idea of the present invention. In the following drawings, in order to make each configuration easy to understand, the actual structure, scale, number, etc. in each structure may be different.

[0011] The Z-axis direction appropriately shown in each figure is a vertical direction with the positive side being the "upper side" and the negative side being the "lower side". The central axis J appropriately shown in each figure is parallel to the Z-axis direction and is a virtual line extending in the vertical direction. In the following description, the axial direction of the central axis J, that is, the direction parallel to the vertical direction, will be simply referred to as the "axial direction", the radial direction centered on the central axis J will be simply referred to as the "radial direction", and the circumferential direction centered on the central axis J will be simply referred to as the "circumferential direction".

[0012] Note that the vertical direction, the upper side, and the lower side are merely names for explaining the arrangement relationship of each part, and the actual arrangement relationship, etc. may be an arrangement relationship other than the arrangement relationship indicated by these names.

[0013] <First Embodiment> As shown in FIG. 1, the motor 1 of the first embodiment is an inner rotor type motor. The central axis of the motor 1 is the central axis J. The motor 1 includes a housing 2, a rotor 3, a stator 10, bearings 5a and 5b, and a heat pipe 50. The housing 2 houses the rotor 3, the stator 10, and the bearings 5a and 5b. The rotor 3 is rotatable about the central axis J. The rotor 3 has a shaft 3a and a rotor body 3b.

[0014] The housing 2 has a lid portion 7 and a bottom plate portion 8. The lid portion 7 has a through hole 7a. The through hole 7a axially penetrates the lid portion 7. A plurality of through holes 7a are provided at intervals in the circumferential direction. The bottom plate portion 8 has a through hole 8a. The through hole 8a axially penetrates the bottom plate portion 8. A plurality of through holes 8a are provided at intervals in the circumferential direction.

[0015] The shaft 3a extends axially along the central axis J. The shaft 3a is, for example, columnar and extends axially about the central axis J. The shaft 3a is rotatably supported about the central axis J by the bearings 5a and 5b. The bearings 5a and 5b are held by the bearing holders 4a and 4b of the housing 2. The rotor body 3b is fixed to the outer peripheral surface of the shaft 3a. Although not shown, the rotor body 3b has a rotor core fixed to the outer peripheral surface of the shaft 3a and magnets fixed to the rotor core.

[0016] The stator 10 faces the rotor 3 radially with a gap therebetween. In the present embodiment, the stator 10 is located radially outside the rotor 3. As shown in FIGS. 2 and 3, the stator 10 has a stator core 20, a plurality of coils 30, and an insulator 40 (not shown in FIG. 2). The stator core 20 has an annular core back 21 surrounding the central axis J and a plurality of teeth 22 extending radially inward from the core back 21. The core back 21 is, for example, cylindrical about the central axis J.

[0017] The plurality of teeth 22 are arranged at intervals along the circumferential direction. The plurality of teeth 22 are, for example, arranged at equal intervals over one circumference along the circumferential direction. In the present embodiment, the plurality of teeth 22 are integrally formed with the core back 21. Each tooth 22 has a substantially rectangular parallelepiped shape that extends linearly along the radial direction. The circumferential dimension of the teeth 22 is substantially constant over the entire radial direction.

[0018] Note that umbrella portions protruding on both circumferential sides may be provided at the radially inner ends of the teeth 22. Further, the teeth 22 may be separate members from the core back 21. In this case, the teeth 22 may be fixed to the core back 21, for example, by press-fitting a convex portion provided at the radially outer end of the teeth 22 into a concave portion provided on the radially inner surface of the core back 21.

[0019] The plurality of coils 30 are respectively mounted on the plurality of teeth 22. In the present embodiment, the coils 30 are mounted on the teeth 22 via the insulators 40. Each tooth 22 passes through the inside of each coil 30 in the radial direction. The radially inner end of the tooth 22 protrudes radially inward of the coil 30.

[0020] The coil 30 is configured by winding a rectangular flat wire as an example. Therefore, the occupation ratio of the coil 30 can be improved as compared with the case of using a round wire. In the present specification, the "rectangular flat wire" is a wire rod having a rectangular or substantially rectangular cross-sectional shape. In the present specification, the "substantially rectangular shape" includes a rounded rectangular shape in which the corners of the rectangular shape are rounded. Although illustration is omitted, the rectangular flat wire constituting the coil 30 in the present embodiment is an enameled wire having an enamel coating on the surface.

[0021] The stator core 20 of this embodiment has at least one hole HL and a slit SL. The hole HL penetrates the stator core 20 in the axial direction. A plurality of holes HL are arranged at intervals along the circumferential direction. The plurality of holes HL are arranged at equal intervals, for example, over one circumference along the circumferential direction. The hole HL is arranged in the core back 21. The plurality of holes HL overlap with the teeth 22 respectively in the radial direction. The hole HL is provided for each tooth 22. The circumferential center position of the hole HL is the same as the circumferential center position of the tooth 22. The outermost position in the radial direction of the hole HL is radially inside the outer circumference of the stator core 20. A heat pipe 50 is held in the hole HL. Since the outermost position in the radial direction of the hole HL is radially inside the outer circumference of the stator core 20, the distance between the coil 30 and the heat pipe 50 can be shortened and the heat from the coil 30 can be efficiently released to the heat pipe 50.

[0022] The slit SL is a space connecting the hole HL and the outside in the radial direction of the stator core 20. The slit SL extends in the axial direction. The circumferential width of the slit SL is smaller than the diameter of the heat pipe 50. Since the circumferential width of the slit SL is smaller than the diameter of the heat pipe 50, it is possible to prevent the heat pipe 50 held in the hole HL from coming out radially outward through the slit SL.

[0023] The heat pipe 50 is a heat conduction element. The heat pipe 50 has an axial sealed container in which a working fluid is sealed in a reduced pressure state. The heat pipe 50 has a capillary structure (wick) on the inner wall of the sealed container. The heat pipe 50 is held in each of the plurality of holes HL. The number of poles in the stator core 20 of this embodiment is 12 poles. Twelve heat pipes 50 are arranged at equal intervals (at 30° intervals) in the circumferential direction. As shown in FIG. 4, an adhesive 51 is filled between the heat pipe 50 and the hole HL. As the adhesive 51, an adhesive with high thermal conductivity is used.

[0024] When the heat pipe 50 is fixed to the hole HL of the stator core 20 without the slit SL by the adhesive 51, it is difficult to fill the adhesive 51 between the hole HL and the heat pipe 50, and there may be a gap. For example, when the adhesive 51 is applied to the inner peripheral surface of the hole HL in advance and the heat pipe 50 is inserted into the hole HL, the adhesive 51 will be extruded. For example, when the adhesive 51 is applied to the outer peripheral surface of the heat pipe 50 and the heat pipe 50 is inserted into the hole HL, the adhesive 51 will be scraped off when it is handled at the insertion side end of the hole HL. Therefore, the adhesive 51 cannot be sufficiently filled between the heat pipe 50 and the hole HL. In this case, the holding property of the heat pipe 50 to the stator core 20 decreases, and there is a state where air with a larger thermal resistance than the state where the adhesive 51 is filled between the hole HL and the heat pipe 50 exists, resulting in a decrease in the efficiency of heat transfer.

[0025] On the contrary, in this embodiment, by providing the slit SL that connects the hole HL and the radially outer side of the stator core 20, the adhesive 51 can be easily and sufficiently spread and filled between the hole HL and the heat pipe 50 by applying the adhesive 51 to the heat pipe 50 inserted into the hole HL through the slit SL. By filling the adhesive 51 between the hole HL and the heat pipe 50 without gaps, the thermal resistance becomes smaller and the efficiency of heat transfer is improved.

[0026] In the axial direction, the heat pipe 50 is longer than the stator core 20. As shown in FIG. 2, the heat pipe 50 protrudes above and below the stator core 20. As shown in FIG. 1, a part of the heat pipe 50 is in contact with the housing 2. The upper and lower ends of the heat pipe 50 are in contact with the housing 2. By the end of the heat pipe 50 being in contact with the housing 2, the absorbed heat can be effectively dissipated through the housing 2, and the heat dissipation efficiency is improved.

[0027] An adhesive 52 is applied between the heat pipe 50 protruding above the stator core 20 and the coil 30. The adhesive 52 connects the heat pipe 50 protruding upward and the coil 30. The heat generated in the coil 30 located above the stator core 20 is transmitted to the heat pipe 50 through the adhesive 52. An adhesive 53 is applied between the heat pipe 50 protruding below the stator core 20 and the coil 30. The adhesive 53 connects the heat pipe 50 protruding downward and the coil 30. The heat generated in the coil 30 located below the stator core 20 is transmitted to the heat pipe 50 through the adhesive 53. As the adhesives 52 and 53, adhesives with high thermal conductivity are used. The adhesives 52 and 53 may be made of the same material as the adhesive 51 or different materials. Alternatively, instead of the adhesives 52 and 53, a heat removal member may be fabricated as a separate part from a material such as a metal having higher thermal conductivity than the adhesive, and the heat removal member may be interposed between the heat pipe 50 and the coil 30. In this case, the heat removal member can be fixed to the heat pipe 50 and the coil 30 with an adhesive. Even when adhesives 52 and 53 with high thermal conductivity are used, compared with, for example, an aluminum material as a metal, the thermal conductivity is on the order of 1 / 10 to 1 / 100. Therefore, by using a heat removal member made of a material such as a metal, the thermal resistance can be further reduced, and the heat of the coil 30 can be effectively removed.

[0028] In the regions where the heat pipe 50 is held in the holes HL of the stator core 20 and where the adhesives 52 and 53 are applied, the heat generated in the coil 30 is transmitted to form a high-temperature region. The heat pipe 50 in the high-temperature region is cooled by the latent heat of vaporization when the internal working fluid evaporates. Therefore, the regions where the heat pipe 50 is held in the holes HL of the stator core 20 and where the adhesives 52 and 53 are applied become heat removal regions. The working fluid evaporated inside the heat pipe 50 releases heat and liquefies in the low-temperature region. The working fluid evaporated inside the heat pipe 50 releases heat and liquefies in the low-temperature region in contact with the housing 2. Therefore, in the heat pipe 50, particularly the region in contact with the housing 2 becomes a heat dissipation region. The working fluid liquefied in the heat dissipation region moves to the high-temperature region by the capillary structure.

[0029] In this embodiment, since the heat pipe 50 does not come into direct contact with the coil 30, the insulating coating of the coil 30 is not damaged. Since the adhesive 51 can be sufficiently spread and filled between the hole HL and the heat pipe 50, the thermal resistance is reduced and the heat generated in the coil 30 can be sufficiently dissipated. If the heat generated in the coil 30 cannot be sufficiently dissipated, the upper limit of the output of the motor 1 will be restricted by the temperature rise of the coil 30. In this embodiment, by sufficiently dissipating the heat generated in the coil 30, the restriction due to the temperature rise of the coil 30 is alleviated, and it becomes possible to increase the output with the motor 1 of the same size and specifications.

[0030] <Second Embodiment> Subsequently, a second embodiment of the motor 1 will be described with reference to FIGS. 5 to 11. In these figures, elements identical to those of the first embodiment shown in FIGS. 1 to 4 may be denoted by the same reference numerals and their description may be omitted. In the motor 1 of the second embodiment, the central axis J is arranged in the horizontal direction. However, when explaining the arrangement relationship of each part, etc., in the Z-axis direction, the positive side is the "upper side" and the negative side is the "lower side".

[0031] As shown in FIG. 5, the motor 1 of the second embodiment is provided in the electric airplane 100. The electric airplane 100 includes a main body portion 110, a rotary wing device 120, and a mounting portion 130. The mounting portion 130 extends in a direction orthogonal to the axial direction from the main body portion 110. The rotary wing device 120 is attached to the mounting portion 130. The rotary wing device 120 is a device that generates an upward thrust for the electric airplane 100. In this embodiment, a plurality of rotary wing devices 120 are provided.

[0032] The rotary wing device 120 includes a motor 1, a front cone portion 101, a rotary wing portion 102, and a rear cone portion 103. The rotary wing portion 102 is provided with a gap above the axial direction of the housing 2. The rotary wing portion 102 is annular with the central axis J as the center. The rotary wing portion 102 has a through hole 102a, a propeller 102b, and a suction hole 102c.

[0033] The through hole 102a penetrates the rotary blade portion 102 in the axial direction. The through hole 102a is coaxial with the central axis J. The upper end of the shaft 3a is inserted into the through hole 102a. The shaft 3a inserted into the through hole 102a is fixed to the rotary blade portion 102. The rotary blade portion 102 fixed to the shaft 3a rotates in synchronization with the rotor body 3b.

[0034] The propeller 102b extends radially outward from the outer peripheral surface of the rotary blade portion 102. A plurality of propellers 102b are provided at intervals in the circumferential direction. The suction hole 102c sucks air from the outside. The suction hole 102c is provided for each of the plurality of propellers 102b. The circumferential position of the suction hole 102c is the same as the circumferential position of the propeller 102b. The upper end of the suction hole 102c opens above the propeller 102b on the outer peripheral surface of the rotary blade portion 102. The suction hole 102c extends downward in a direction toward the lower side as it extends radially inward from the upper end. The lower end of the suction hole 102c opens on the lower surface of the rotary blade portion 102. The position of the lower end of the suction hole 102c is a position that axially opposes the through hole 7a of the housing 2 when the rotary blade portion 102 rotates. The air sucked from the upper end of the suction hole 102c can flow into the inside of the housing 2 through the through hole 7a from the lower end of the suction hole 102c.

[0035] The housing 2 of the motor 1 is attached above the attachment portion 130. The attachment portion 130 has a through hole 131 and a through hole 132. The through hole 131 penetrates the attachment portion 130 in the axial direction. The through hole 131 is provided at a position axially opposing the hole HL and the heat pipe 50. The through hole 131 holds the heat pipe 50. The heat pipe 50 is inserted through the through hole 131. The through hole 132 penetrates the attachment portion 130 in the axial direction. The through hole 132 axially overlaps with the through hole 8a of the bottom plate portion 8. When the through hole 132 axially overlaps with the through hole 8a of the bottom plate portion 8, the air that has flowed into the inside of the housing 2 from the suction hole 102c can flow into the through hole 132 of the attachment portion 130 through the through hole 8a of the bottom plate portion 8.

[0036] The motor 1 has a heat radiating portion 60 and a mounting portion 70. The heat radiating portion 60 is disposed on the lower side, which is one axial side of the housing 2, via the mounting portion 130. The heat radiating portion 60 has a plurality of layers of fin portions 61 arranged in the axial direction. As shown in FIG. 6, each layer of the fin portion 61 is an annular shape extending in the circumferential direction. Each layer of the fin portion 61 has a plurality of fins 62 equally divided in the circumferential direction. Each layer of the fin portion 61 has six fins 62 equally divided in the circumferential direction. The circumferential angle of the fin 62 is 60° equally divided with respect to the entire circumference. The plurality of fins 62 have the same inner diameter dimension and outer diameter dimension. By making the inner diameter dimension and the outer diameter dimension of the plurality of fins 62 the same, the fins 62 can be manufactured from an annular material without gaps, and material loss can be reduced.

[0037] As shown in FIG. 7, the fin 62 has a fin body 62a and a flange portion 62b. The fin body 62a has a through hole 62c penetrating in the axial direction. Two through holes 62c are provided at intervals in the circumferential direction. The central position of the through hole 62c is at a position 15° on both sides in the circumferential direction from the circumferential center of the fin 62. The central positions of the two through holes 62c are separated by 30° in the circumferential direction. As shown in FIG. 8, the fin body 62a has a boss 62d protruding downward. The boss 62d is coaxial with the through hole 62c. The through hole 62c penetrates the fin body 62a in the axial direction including the boss 62d. In each layer of the fin portion 61, the heat pipe 50 is inserted into the through hole 62c of the fin 62. The heat pipe 50 inserted into the through hole 62c is fixed to the fin 62 by an adhesive 54. As the adhesive 54, an adhesive having a high thermal conductivity is used.

[0038] The flange portion 62b is provided at both circumferential ends of the fin body 62a. The flange portion 62b is located below the fin body 62a. The flange portion 62b is parallel to the fin body 62a. The two flange portions 62b have the same axial distance from the fin body 62a.

[0039] As shown in FIG. 9, the mounting portion 70 is annular with the central axis J as the center. The diameter dimension of the inner peripheral surface of the mounting portion 70 is the diameter dimension of the inner periphery of the fin 62. The diameter dimension of the outer peripheral surface of the mounting portion 70 is the diameter dimension of the outer periphery of the fin 62. The diameter dimension of the inner peripheral surface of the mounting portion 70 and the diameter dimension of the inner periphery of the fin 62 are larger than the outermost diameter dimension in the radial direction of the through hole 132 of the mounting portion 130. Therefore, the air flowing into the inside of the housing 2 from the suction hole 102c can flow into the internal space of the heat dissipation portion 60 through the through hole 8a of the bottom plate portion 8 and the through hole 132 of the mounting portion 130. The air flowing into the internal space of the heat dissipation portion 60 from the suction hole 102c through the inside of the housing 2 can be exhausted to the outside through the gaps between the fins 62. Therefore, the heat generated in the coil 30 can be removed by heat exchange with the air sucked from the suction hole 102c in addition to the heat removal by the heat pipe 50.

[0040] The mounting portion 70 has a plurality of through holes 71. Twelve through holes 71 are provided at a pitch of 30° in the circumferential direction. The through holes 71 penetrate the mounting portion 70 in the axial direction. The radial position of the through holes 71 is the same as the radial position of the hole HL. The lower end side of the heat pipe 50 is inserted through the through holes 71. The lower end of the heat pipe 50 contacts the upper surface of the rear cone portion 103 as shown in FIG. 5. The heat pipe 50 inserted through the through holes 71 extends upward and its upper end contacts the housing 2.

[0041] That is, the heat pipe 50 penetrates the heat dissipation portion 60. When the central axis J and the heat pipe 50 are arranged horizontally, the influence of gravity acting on the working fluid in the heat pipe 50 is small. Therefore, the working fluid liquefied in the heat dissipation region can move to the heat removal region more easily than when the central axis J and the heat pipe 50 are arranged vertically. As a result, even when the heat pipe 50 is provided with a length penetrating the heat dissipation portion 60, it is difficult to hinder the movement of the working fluid from the heat dissipation region to the heat removal region.

[0042] The heat pipe 50 can dissipate heat as a heat dissipation region throughout the entire axial direction of the heat dissipation portion 60 by passing through the heat dissipation portion 60. Therefore, the heat generated in the coil 30 can be effectively dissipated by the heat dissipation portion 60. The fins 62 are provided with bosses 62d in the penetrating portion (penetration holes 62c) of the heat pipe 50, thereby improving the mechanical strength. The fins 62 are provided with bosses 62d in the penetrating portion (penetration holes 62c) of the heat pipe 50, thereby increasing the contact area with the heat pipe 50. Therefore, the heat dissipation efficiency of the heat pipe 50 can be improved.

[0043] The fins 62 are stacked in a plurality of layers axially on the upper side of the mounting portion 70. The fins 62 in the fin portions 61 adjacent to each other in the axial direction are offset from each other by a half pitch in the circumferential direction and overlap in the axial direction. Specifically, as shown in FIG. 9, the fins 62 of the first layer (indicated by reference numeral 62-1) and the fins 62 of the second layer (indicated by reference numeral 62-2) are arranged with a 30° offset from each other, which is a half pitch, in the circumferential direction.

[0044] When the six fins 62-1 of the first layer are arranged in the circumferential direction, the through holes 62c of the fins 62-1 are arranged at 30° intervals in the circumferential direction. When the six fins 62-2 of the second layer are arranged in the circumferential direction, the through holes 62c of the fins 62-2 are arranged at 30° intervals in the circumferential direction. The fins 62-1 of the first layer and the fins 62-2 of the second layer are arranged with a 30° offset in the circumferential direction. Therefore, the through holes 62c of the fins 62-1 and the through holes 62c of the fins 62-2 overlap in the axial direction. Therefore, after inserting the through holes 62c into the heat pipe 50 extending upward from the mounting portion 70 and arranging the fins 62-1 of the first layer (odd-numbered layers) side by side in the circumferential direction, the fins 62-2 of the second layer (even-numbered layers) are offset by a half pitch in the circumferential direction with respect to the fins 62-1, and the through holes 62c are inserted into the heat pipe 50. As a result, as shown in FIG. 6, the fins 62 in the fin portions 61 adjacent to each other in the axial direction are offset from each other by a half pitch in the circumferential direction and overlap in the axial direction.

[0045] When fins 62 of the same shape in adjacent fin portions 61 in the axial direction overlap in the axial direction without shifting in the circumferential direction, there may be a case where sufficient gaps cannot be secured between the fins 62 laminated in the axial direction. By arranging the fins 62 in adjacent fin portions 61 in the axial direction so as to be shifted from each other by a half pitch in the circumferential direction, it is possible to secure a circumferential gap and a gap between the fins 62 adjacent in the axial direction in each layer.

[0046] In addition to obtaining the same operations and effects as those of the first embodiment, the motor 1 of the present embodiment can more efficiently dissipate the heat generated in the coil 30 by arranging the heat pipe 50 through the heat dissipation portion 60 when the central axis J is arranged in the horizontal direction.

[0047] Therefore, in the electric airplane 100 having the motor 1, the rear cone portion 103 and the heat dissipation portion 60 can dissipate the heat generated by the motor 1 with the heat dissipation portion 60 having a large air cooling area and exhibiting sufficient cooling performance while maintaining the rectifying function of the rearward flow caused by the rotation of the propeller 102b. For this reason, in the motor 1 mounted on the electric airplane 100, the limitation due to the temperature rise of the coil 30 is alleviated, and the power weight ratio and the maximum output of the continuous operation can be significantly increased with the motor 1 of the same size and specifications.

[0048] <Modification of the Second Embodiment> A modification of the second embodiment will be described with reference to FIGS. 10 and 11. As shown in FIG. 10, the fin 62 has a surface 62e and cutout portions 63a and 63b. The surface 62e is located on the outer periphery of the fin 62. The surface 62e is inclined downward in the axial direction as it goes radially outward.

[0049] By providing the inclined surface 62e, as shown in FIG. 11, in the heat dissipation portion 60, an action indicated by an arrow T2 for sucking out the internal air from the fin 62 is generated by the airflow indicated by an arrow T1 flowing outside the fin 62. For this reason, the air volume of the air passing through the inside of the motor 1 increases, so that the cooling efficiency can be improved.

[0050] The cutout portion 63a is a hole that penetrates the fin 62. The cutout portion 63a is arc-shaped and extends from the circumferential center of the fin 62 to both circumferential sides in the axial direction view. The cutout portion 63b is a hole that penetrates the fin 62. The cutout portion 63b is disposed on the outer side in the circumferential direction than the through hole 62c. The cutout portion 63b is circular in the axial direction view. By providing the cutout portions 63a and 63b in the fin 62, the fin 62 can be lightened. By lightening the fin 62, the cooling performance per unit weight of the fin 62 can be improved.

[0051] In the above-described second embodiment, the configuration in which the heat pipe 50 has a length extending from the housing 2 to the mounting portion 70 is exemplified, but the present invention is not limited to this configuration. When the heat pipe 50 is long, it may take time for assembly. In this case, a configuration may be adopted in which a first heat pipe having a length from the housing 2 to the mounting portion 130 and a second heat pipe having a length from the heat radiating portion 60 to the mounting portion 130 are provided respectively.

[0052] <Third Embodiment> Subsequently, a third embodiment of the motor 1 will be described with reference to FIGS. 12 and 13. In these figures, the same reference numerals are given to the components identical to those of the second embodiment shown in FIGS. 5 to 11, and the description thereof may be omitted. In the motor 1 of the third embodiment, the central axis J is arranged in the vertical direction.

[0053] As shown in FIG. 12, the rotary blade portion 102 has a recess 102d on the lower side facing the housing 2. The recess 102d tapers upward as it goes from the radially outer side to the radially inner side. The lid portion 7 of the housing 2 in the motor 1 has a plurality of rib portions 7b. The circumferential position of the rib portion 7b is the same as the circumferential position of the hole HL. A through hole 7a is provided between the rib portions 7b adjacent to each other in the circumferential direction. The rib portion 7b is inclined upward as it goes from the radially outer side to the radially inner side.

[0054] As shown in Fig. 13, the rib portion 7b has a groove portion 7c extending in the radial direction. The groove portion 7c opens upward. The bottom of the groove portion 7c has a semi-circular cross-sectional shape. The radial dimension of the bottom of the groove portion 7c is the same as the radial dimension of the heat pipe 50. A rib portion 9 is fitted into the groove portion 7c from above. The rib portion 9 extends in the radial direction. The rib portion 9 has a groove portion 9a extending in the radial direction. The groove portion 9a opens downward. The bottom of the groove portion 9a has a semi-circular cross-sectional shape. The radial dimension of the bottom of the groove portion 9a is the same as the radial dimension of the heat pipe 50.

[0055] The heat pipe 50 has a curved portion that bends inward in the radial direction as it goes upward above the coil 30. The upper side of the heat pipe 50 extends linearly upward as it goes from the radial outer side to the radial inner side above the curved portion. The region where the heat pipe 50 extends linearly above the curved portion is inserted into the groove portion 7c of the rib portion 7b. The lower side of the heat pipe 50 inserted into the groove portion 7c is held by the bottom of the groove portion 7c. The upper side of the heat pipe 50 inserted into the groove portion 7c is held by the bottom of the groove portion 9a in the rib portion 9. The rib portion 9 is fixed to the rib portion 7b with an adhesive. The upper side of the heat pipe 50 is fixed with an adhesive while being held between the rib portion 7b and the rib portion 9. An adhesive with high thermal conductivity is used as the adhesive. The region where the heat pipe 50 is held between the rib portion 7b and the rib portion 9 becomes a heat dissipation region.

[0056] When the central axis J and the heat pipe 50 are arranged vertically, the influence of gravity acting on the working fluid in the heat pipe 50 is large. If the heat dissipation region of the heat pipe 50 is on the lower side and the heat pipe 50 is long, it may be difficult for the working fluid liquefied in the heat dissipation region to move through the capillary structure. As shown in Fig. 12, the lower end of the heat pipe 50 is located at the mounting portion 130. By positioning the lower end of the heat pipe 50 at the mounting portion 130, it is possible to prevent the liquefied working fluid from not moving to the heat removal region when the lower end of the heat pipe 50 is located at the heat dissipation portion 60.

[0057] The heat pipe 50 can increase the heat dissipation area of the heat pipe 50 by linearly extending upward from the radially outer side to the radially inner side above the curved portion. The lengthened heat dissipation area of the heat pipe 50 is located on the upper side. Therefore, the working fluid liquefied in the heat dissipation area can easily move to the lower heat removal area by its own weight.

[0058] Therefore, in the present embodiment, when the central axis J is arranged in the vertical direction, the heat generated by the coil 30 can be efficiently dissipated.

[0059] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to such examples. The various shapes and combinations of the constituent members shown in the above examples are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

[0060] For example, in the above embodiment, the fin portion 61 having a plurality of fins 62 equally divided in the circumferential direction is illustrated. However, the present invention is not limited to this configuration, and the fin portion 61 may be composed of a single annular member.

[0061] Although illustration is omitted, a configuration in which straightening fins extending in the axial direction are provided on the outer periphery of the heat dissipation portion 60 may be adopted. By providing the straightening fins, the rearward flow caused by the rotation of the propeller 102b can be further rectified.

Description of Reference Numerals

[0062] 1... motor, 2... housing, 3... rotor, 10... stator, 20... stator core, 21... core back, 22... teeth, 50... heat pipe, 51, 52, 53... adhesive, 60... heat dissipation portion, 61... fin portion, 62... fin, 62c... through hole (penetrating portion), 62d... boss, 62e... surface, HL... hole, J... central axis, SL... slit

Claims

1. A rotor rotatable about a central axis, A stator radially opposed to the rotor with a gap therebetween, A heat pipe, Comprising, The stator, A stator core having an annular core back surrounding the central axis and teeth extending radially inward from the core back, A coil wound around the teeth, Having, The stator core, At least one hole penetrating in the axial direction of the central axis, A slit which is a space connecting the hole and the radially outer side of the stator core, Having, The heat pipe is held in the hole and extends axially along the hole, An adhesive is filled between the hole and the heat pipe, The coil, A portion located on one axial side of the stator core, A portion located on the other axial side of the stator core, Having, The heat pipe is linear and has a portion protruding on one axial side of the stator core and a portion protruding on the other axial side of the stator core, An adhesive is applied to at least one of the space between the portion of the heat pipe protruding on one axial side of the stator core and the portion of the coil located on one axial side of the stator core, and the space between the portion of the heat pipe protruding on the other axial side of the stator core and the portion of the coil located on the other axial side of the stator core. Motor.

2. The outermost position in the radial direction of the hole is radially inside the outer circumference of the stator core. The motor according to claim 1.

3. The circumferential width of the slit is smaller than the diameter of the heat pipe. The motor according to claim 1 or 2.

4. Having a housing for accommodating the rotor and the stator, At least a part of the axial end of the heat pipe is in contact with the housing. The motor according to any one of claims 1 to 3.

5. A housing for accommodating the rotor and the stator, A heat dissipation part arranged on one axial side of the housing, Having, The heat pipe penetrates the heat dissipation part. The motor according to any one of claims 1 to 3.

6. The heat dissipation part has a plurality of layers of fin parts arranged axially. The motor according to claim 5.

7. Each layer of the fin part has a plurality of fins equally divided in the circumferential direction. The fins in the fin portions adjacent to each other in the axial direction are offset from each other by a half pitch in the circumferential direction and overlap in the axial direction. The motor according to claim 6.

8. At least one of the fins has, on its outer periphery, a surface that inclines toward one side in the axial direction as it goes toward the radially outer side. The motor according to claim 7.

9. A boss is provided in a penetrating portion of the heat pipe for the fins. The motor according to claim 7 or 8.

Images