Motor

Abstract

To provide a structure capable of securing an insulation performance between a radiation component which promotes radiation from an electronic component accommodated inside, and a shaft in a molded motor.SOLUTION: A motor 1 comprises a stationary part 2 and a rotary part 3. The stationary part 2 includes a stator 21, a casing 22, a cover 23 holding a bearing part 60, and a circuit board 24. The rotary part 3 includes a rotor 32 and a shaft 31. The circuit board 24 includes an electronic component 26. The casing 22 is opened in a casing opening part 223 and accommodates the electronic component 26 in an internal space 220. The cover 23 covers the casing opening part 223 from one side in an axial direction of the circuit board 24. The cover 23 includes a resin cover body part 231 and a radiation component 232 of which heat conductivity is higher than that of the cover body part 231. An end of the radiation component 232 is directly or indirectly in contact with the electronic component 26. The cover body part 231 is interposed between the bearing part 60 and the radiation component 232.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor. [Background technology]

[0002] Conventionally, there is a molded motor in which the stator of the motor is molded from resin to form a casing, and the rotor is supported inside the casing via bearings. This type of motor has excellent waterproofing of the stator, and excellent vibration and sound insulation against the vibration of the stator when the motor is driven. A conventional molded motor is described, for example, in JP 2007-6603 A. [Patent Document 1] JP 2007-6603 A Summary of the Invention [Problem to be solved by the invention]

[0003] The DC brushless motor of JP 2007-6603 A has a stator assembly (6) in which the stator is molded as one unit, and a rotor assembly. The bearing (5) on the side opposite to the output shaft is supported by a bracket (10) and fixed to the stator assembly (6). A printed circuit board (8) on which a driving IC (7) is mounted is attached to the stator assembly (6). Heat dissipation silicon (11) is applied between the bracket (10) and the driving IC (7). A heat sink (12) made of aluminum is attached to the bracket (10). This allows heat generated in the driving IC (7) to be dissipated by the bracket (10) and the heat sink (12) via the heat dissipation silicon (11) (see paragraphs 0016, 0017, 0020, etc.).

[0004] A shaft (3) is fixed to the inner ring of the bearing (5). The shaft (3) is connected to a rotating part or a reduction gear mechanism of a device on which an operator performs maintenance. However, as described above, the bearing (5) is supported by the bracket (10), but only heat dissipation silicone (11) is applied between the bracket (10) and the driving IC (7). For this reason, sufficient insulation performance is not ensured between the driving IC (7) and the shaft (3).

[0005] The object of the present invention is to provide a structure in a molded motor having a casing with an integrally molded stator, which can ensure insulation performance between a heat dissipation component that promotes heat dissipation from electronic components housed inside and a shaft to which the rotating part or reduction mechanism of the equipment to be driven is connected. [Means for solving the problem]

[0006] A first exemplary invention of the present application is a motor having a stationary portion and a rotating portion that rotates around a central axis via a bearing portion, the stationary portion having a stator, a casing that houses at least a part of the stator, a cover that is fixed to the casing and that directly or indirectly holds the bearing portion, and a circuit board that extends in a radial direction and is electrically connected to the stator, the rotating portion having a rotor and a shaft that is attached to the rotor and extends along the central axis, the circuit board has electronic components for driving the motor, and the casing has at least one axially aligned portion. the cover has an internal space that opens at a casing opening formed on one side and continues from the casing opening to the other axial side, the electronic component is located in the internal space, the cover covers the casing opening from one axial side of the circuit board, and has a resin cover main body and a heat dissipation component attached to the cover main body and having a higher thermal conductivity than the cover main body, the end of the heat dissipation component on the other axial side contacts the electronic component directly or indirectly via a separate member, and the cover main body is interposed at least in the radial direction between the bearing portion and the heat dissipation component. Effect of the Invention

[0007] According to the first exemplary invention of the present application, a resin cover body, which is an insulator, is interposed between a heat dissipation component that promotes heat dissipation from electronic components and a bearing that rotatably supports a shaft. This ensures sufficient insulation between the electronic components and heat dissipation component and the bearing that supports the shaft. As a result, it is possible to prevent electricity flowing through the circuit board from being transmitted to the shaft via the heat dissipation component and the bearing. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view of a motor according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of a cover and an upper bearing housing portion according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view of a cover main body and an upper bearing housing portion according to the first embodiment. [Figure 4] FIG. 4 is a perspective view of the heat dissipation component according to the first embodiment. [Diagram 5] FIG. 5 is a perspective view of the cover and the upper bearing housing according to the first embodiment. [Figure 6] FIG. 6 is a partial vertical cross-sectional view of the motor according to the first embodiment. [Figure 7] FIG. 7 is a perspective view of a cover and an upper bearing housing portion according to a modified example. [Figure 8] FIG. 8 is a partial vertical cross-sectional view of a motor according to a modified example. [Figure 9] FIG. 9 is a partial vertical cross-sectional view of a motor according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In this application, the direction parallel to the central axis of the motor is referred to as the "axial direction", the direction perpendicular to the central axis of the motor is referred to as the "radial direction", and the direction along the arc centered on the central axis of the motor is referred to as the "circumferential direction". In this application, the axial direction is referred to as the up-down direction, and the circuit board side with respect to the stator is referred to as the up-down direction, and the shape and positional relationship of each part will be described. However, this definition of the up-down direction is not intended to limit the orientation of the motor according to the present invention during manufacture and use. That is, in the following embodiments and modifications, the "upper side (upper end)" is to be read as "one axial side (end on one axial side)", and the "lower side (lower end)" is to be read as "the other axial side (end on the other axial side)". In this application, the "parallel direction" also includes a substantially parallel direction. In this application, the "orthogonal direction" also includes a substantially orthogonal direction.

[0010] <1. First embodiment> <1-1. Motor configuration> 1 is a vertical cross-sectional view of a motor 1. This motor 1 is used in home appliances such as indoor and outdoor units of air conditioners. However, the motor of the present invention may also be used for applications other than home appliances. For example, the motor of the present invention may be mounted on transportation equipment such as automobiles and trains, office automation equipment, medical equipment, tools, large industrial facilities, etc., to generate various driving forces.

[0011] As shown in Fig. 1, motor 1 has a stationary part 2 and a rotating part 3. Stationary part 2 is fixed to a frame of a device to be driven. Rotating part 3 is supported rotatably about a central axis 9 extending vertically relative to stationary part 2 via bearing part 60 (described later). A rotating part or a reduction mechanism of the device to be driven is fixed to shaft 31 (described later) of rotating part 3.

[0012] The stationary part 2 of the present embodiment has a stator 21, a casing 22, a cover 23, a circuit board 24, and a bearing housing part 25. The bearing housing part 25 includes an upper bearing housing part 251 and a lower bearing housing part 252. The upper bearing housing part 251 forms a part of the cover 23. The lower bearing housing part 252 forms a part of the casing 22. However, in the following, for ease of understanding, the cover 23 and the upper bearing housing part 251 are distinguished from each other, and the casing 22 and the lower bearing housing part 252 are distinguished from each other.

[0013] The stator 21 is an armature that generates a magnetic flux in response to a driving current supplied from an external power source via a circuit board 24. The stator 21 annularly surrounds the radial outside of a rotor 32, which will be described later. The stator 21 has a stator core 211, an insulator 212, and a plurality of coils 213. The stator core 211 is made of laminated steel plates in which electromagnetic steel plates are laminated in the axial direction. The stator core 211 is fixed to the casing 22. The stator core 211 also has an annular core back 41 and a plurality of teeth 42 that protrude radially inward from the core back 41. The core back 41 is disposed approximately coaxially with the central axis 9. The plurality of teeth 42 are arranged at approximately equal intervals in the circumferential direction.

[0014] The insulator 212 is made of resin, which is an insulating material. The insulator 212 is attached to the stator core 211. The upper surface, lower surface, and both circumferential side surfaces of each tooth 42 are covered with the insulator 212. The coil 213 is made of a conductive wire wound around the tooth 42 with the insulator 212 interposed therebetween. The insulator 212 is interposed between the stator core 211 and the coil 213, thereby preventing an electrical short circuit between the stator core 211 and the coil 213.

[0015] The casing 22 is a resin member that holds the stator 21 and a lower bearing portion 62, which will be described later. The casing 22 of this embodiment is an insert molded product obtained by pouring resin into a mold that holds the stator 21 and a lower bearing housing portion 252. The casing 22 has a cylindrical portion 221 and a bottom plate portion 222.

[0016] The cylindrical portion 221 extends in an approximately cylindrical shape in the axial direction. The rotor 32 is disposed radially inside the cylindrical portion 221. In this embodiment, the surfaces of the stator 21, except for the radially inner end faces of the teeth 42, are covered with the resin forming the casing 22. This can prevent water from entering the inside of the stator 21. In addition, the coil 213 and the stator core 211 of the stator 21 can be electrically insulated. However, the entire stator 21, including the radially inner end faces of the teeth 42, may be covered with the resin forming the casing 22. In other words, the casing 22 may be any that accommodates at least a part of the stator 21.

[0017] Bottom plate portion 222 expands in an annular shape radially inward from the lower end of cylindrical portion 221. Bottom plate portion 222 is located lower than stator 21 and rotor 32. Bottom plate portion 222 covers an outer circumferential surface and a part of the lower surface of lower bearing housing portion 252, and holds lower bearing housing portion 252.

[0018] The casing 22 also has an internal space 220 that opens at a casing opening 223 at the upper end of the cylindrical portion 221 and continues downward from the casing opening 223. A circuit board 24 including electronic components 26 (described later) of the stationary portion 2, and a part of a shaft 31 (described later) and the rotor 32 of the rotating portion 3 are located in the internal space 220. This allows the entire motor 1 to be made compact in the axial direction. However, the position at which the casing opening 223 is formed is not limited to this. The casing opening 223 may be formed on at least one of the upper and lower sides of the casing 22.

[0019] The cover 23 is disposed above the casing 22 and is a generally plate-shaped member that expands in a radial direction around the upper bearing housing portion 251 in an annular shape. The cover 23 of this embodiment is an insert molded product obtained by pouring resin into a mold that holds the heat dissipation component 232 and the upper bearing housing portion 251, which will be described later. The resin hardens to form the cover main body portion 231. The cover main body portion 231 covers the outer peripheral surface and a part of the lower surface of the upper bearing housing portion 251, and holds the upper bearing housing portion 251. In this way, by having the resin cover main body portion 231, the reverberation (noise) of the cover main body portion 231 that occurs due to vibration from the motor 1 can be kept low compared to the case of using a metal cover.

[0020] An annular recess 230 is formed on the lower surface of the cover 23. The recess 230 is recessed upward from the lower surface of the peripheral edge of the cover 23. The upper end of the cylindrical portion 221 of the casing 22 fits into the recess 230. As a result, the cover 23 and the casing 22 are fixed to each other by press-fitting. The cover 23 covers the casing opening 223 from above the circuit board 24. This prevents water and foreign matter from entering the inside of the casing 22. A more detailed structure of the cover 23 will be described later.

[0021] The circuit board 24 extends in the radial direction above the stator 21 and the rotor 32 and below the cover 23. An electronic circuit including electronic components 26 for driving the motor 1 is mounted on the surface of the circuit board 24. An end of a conductor (not shown) constituting the coil 213 is drawn upward and electrically connected to the electronic circuit. That is, the circuit board 24 is electrically connected to the stator 21. In addition, a conductor (not shown) extending from an external power source is electrically connected to the circuit board 24. That is, the coil 213 and the external power source are electrically connected via the circuit board 24. The current supplied from the external power source flows to the coil 213 via the circuit board 24. The circuit board 24 may be electrically connected to a control circuit mounted on the device to be driven, and may receive a signal line from the control circuit.

[0022] The electronic components 26 are classified into a first electronic component 261 and a second electronic component 262. The first electronic component 261 is an electronic component that is relatively prone to heat generation among the electronic components mounted on the circuit board 24. The first electronic component 261 includes, for example, a switching element such as a FET or an IGBT. The first electronic component 261 also includes a power semiconductor in which a plurality of switching elements are housed in one package. The second electronic component 262 is an electronic component that is relatively unlikely to heat generation among the electronic components mounted on the circuit board 24. Furthermore, in this embodiment, a thermally conductive sheet 240 (separate member) that contacts the first electronic component 261 is disposed on the upper side of the circuit board 24. The thermally conductive sheet 240 is made of, for example, an elastic sheet containing silicone rubber and having high thermal conductivity.

[0023] The upper bearing housing 251 has a generally cylindrical shape with a closed top. As described above, the cover 23 is an insert molded product obtained by pouring resin into a mold that holds the heat dissipation component 232 and the upper bearing housing 251, which will be described later. That is, the upper bearing housing 251 is fixed to the cover body 231 of the cover 23 by molding the molded resin. The upper end of the shaft 31 and the upper bearing 61, which will be described later, are housed inside the upper bearing housing 251. The material of the upper bearing housing 251 is a metal having electrical conductivity, such as iron or aluminum.

[0024] The lower bearing housing portion 252 has a substantially annular shape. As described above, the casing 22 is an insert molded product obtained by pouring resin into a mold in which the stator 21 and the lower bearing housing portion 252 are held. That is, the lower bearing housing portion 252 is fixed to the bottom plate portion 222 of the casing 22 by molding the molded resin. A lower bearing portion 62 that rotatably supports the shaft 31 described below is housed inside the lower bearing housing portion 252. The material of the lower bearing housing portion 252 is a conductive metal such as iron or aluminum.

[0025] The rotating part 3 has a shaft 31 and a rotor 32 .

[0026] The shaft 31 is a columnar member extending in the vertical direction along the central axis 9. The shaft 31 is supported rotatably about the central axis 9. The lower end of the shaft 31 protrudes downward beyond the lower end of the casing 22. For example, an air conditioner fan, which is a rotating part of the device to be driven, is attached to the lower end of the shaft 31. The lower end of the shaft 31 may be connected to a driving part other than the fan via a power transmission mechanism such as a gear.

[0027] In this embodiment, the shaft 31 protrudes downward, but the present invention is not limited to this. The shaft 31 may protrude upward beyond the cover 23, and its upper end may be connected to a driving unit. The shaft 31 may also protrude both downward from the casing 22 and above the cover 23, and both its lower end and upper end may be connected to a driving unit.

[0028] The rotor 32 is an annular member that is disposed radially inside the stator 21 and around the shaft 31 and rotates together with the shaft 31. The rotor 32 has a rotor core 321 and a plurality of magnets 322.

[0029] The rotor core 321 is made of laminated steel plates in which electromagnetic steel plates are laminated in the axial direction. A rotor through hole 320 is provided on the radially inner side of the rotor core 321. The rotor through hole 320 penetrates the rotor 32 in the axial direction along the central axis 9. The shaft 31 is inserted into the rotor through hole 320 and attached to the inner circumferential surface of the rotor core 321 by press-fitting. However, the shaft 31 may be attached to the rotor core 321 by adhesion instead of or in addition to the press-fitting.

[0030] The multiple magnets 322 are disposed around the rotor core 321. The radially outer surface of each magnet 322 is a magnetic pole face that faces the radially inner end faces of the teeth 42 of the stator 21. The multiple magnets 322 are arranged at equal intervals in the circumferential direction such that the N-pole magnetic pole faces and the S-pole magnetic pole faces are arranged alternately.

[0031] It should be noted that a ring-shaped magnet may be used instead of the multiple magnets 322. When using a ring-shaped magnet, it is sufficient that the outer peripheral surface of the magnet is magnetized with N poles and S poles alternately in the circumferential direction. The multiple magnets 322 may be arranged around the rotor core 321 as in this embodiment, or may be arranged in a state of being embedded inside the rotor core 321.

[0032] The bearing unit 60 includes an upper bearing unit 61 and a lower bearing unit 62. The upper bearing unit 61 rotatably supports the shaft 31 above the rotor 32. The lower bearing unit 62 rotatably supports the shaft 31 below the rotor 32. The upper bearing unit 61 and the lower bearing unit 62 of this embodiment are both ball bearings having a sphere 601, an outer ring 602, and an inner ring 603. In the ball bearing, the outer ring 602 and the inner ring 603 rotate relative to each other via the sphere 601. The sphere 601, the outer ring 602, and the inner ring 603 are made of a conductive metal such as iron. That is, the upper bearing unit 61 and the lower bearing unit 62 are both connected between the outer peripheral surface and the inner peripheral surface by a conductive member.

[0033] In this embodiment, the sphere 601, the outer ring 602, and the inner ring 603 are entirely made of a conductive material, but the present invention is not limited to this. For example, even if an insulating material is used in part of the upper bearing portion 61 and the lower bearing portion 62, it is sufficient that the outer peripheral surface and the inner peripheral surface of the upper bearing portion 61 and the lower bearing portion 62 are connected by a conductive member. Also, although a ball bearing is used as the bearing in this embodiment, other types of bearings such as a sleeve bearing may be used as long as the outer peripheral surface and the inner peripheral surface of the bearing are conductive.

[0034] The outer ring of the upper bearing portion 61 is fixed to the upper bearing housing portion 251. As a result, the outer ring of the upper bearing portion 61 is electrically connected to the upper bearing housing portion 251. The outer ring of the lower bearing portion 62 is fixed to the lower bearing housing portion 252. As a result, the outer ring of the lower bearing portion 62 is electrically connected to the lower bearing housing portion 252. Furthermore, the inner rings of each of the upper bearing portion 61 and the lower bearing portion 62 are fixed to the shaft 31.

[0035] When the motor 1 is driven, electricity is applied from an external power source to the first electronic component 261 and the second electronic component 262 on the circuit board 24. The first electronic component 261 and the second electronic component 262 generate a drive current for applying electricity to the coil 213 and control the application of electricity. When the drive current is supplied to the coil 213, a magnetic flux is generated in the multiple teeth 42 of the stator core 211. Then, a circumferential torque is generated by the action of the magnetic flux between the teeth 42 and the magnet 322 mounted on the rotor 32. As a result, the rotating part 3 rotates around the central axis 9. Also, a device directly or indirectly attached to the shaft 31 rotates together with the rotating part 3.

[0036] As described above, the upper bearing portion 61 is supported by the metallic upper bearing housing portion 251. The lower bearing portion 62 is supported by the metallic lower bearing housing portion 252. This prevents relative dimensional changes and deformation between the upper bearing portion 61 and the upper bearing housing portion 251, and between the lower bearing portion 62 and the lower bearing housing portion 252, even if the temperature of each portion rises when the motor 1 is in operation. This prevents the rotating portion 3 from spinning freely, and maintains high rotation accuracy.

[0037] <1-2. Detailed structure of the cover> Next, the structure of the cover 23 will be described in more detail.

[0038] 2 is a perspective view of the cover 23 and the upper bearing housing portion 251. As shown in FIG. 2, the cover 23 has the above-mentioned cover body portion 231 and the heat dissipation component 232. The cover body portion 231 is made of resin. On the other hand, the material of the heat dissipation component 232 is a metal such as aluminum. Therefore, the heat dissipation component 232 has a higher thermal conductivity than the cover body portion 231.

[0039] FIG. 3 is a perspective view of the cover body 231 and the upper bearing housing 251 as viewed from above. FIG. 4 is a perspective view of the heat dissipation component 232. FIG. 5 is a perspective view of the cover 23 and the upper bearing housing 251 as viewed from below. As shown in FIG. 3, the cover body 231 formed by resin injection molding has a plate-shaped portion 51 and a hole portion 52. The plate-shaped portion 51 spreads in a plate shape in the horizontal direction. The hole portion 52 is a trace of the heat dissipation component 232 placed during resin injection molding, and penetrates the plate-shaped portion 51 in the axial direction. That is, as shown in FIGS. 2 to 4, in the cover 23 formed by resin injection molding, the heat dissipation component 232 is placed in the hole portion 52 and attached to the cover body 231. Also, as shown in FIG. 5, the heat dissipation component 232 is exposed below the cover 23.

[0040] As shown in FIG. 1, the lower end of the heat dissipation component 232 indirectly contacts the first electronic component 261 via the heat conductive sheet 240 having a high thermal conductivity. Also, as shown in FIG. 2 and FIG. 4, a plurality of fins 71 exposed to the outside of the motor 1 are provided on the upper surface of the heat dissipation component 232. Each fin 71 is a protrusion protruding upward. This allows the heat generated in the first electronic component 261 to be dissipated from the heat dissipation component 232 to the outside of the motor 1 via the heat conductive sheet 240. In particular, in this embodiment, the heat dissipation component 232 is exposed below the cover 23 and directly contacts the heat conductive sheet 240 without an air layer, so that the heat dissipation performance is further improved. Note that the heat conductive sheet 240 may not be provided. That is, the lower end of the heat dissipation component 232 may directly contact the first electronic component 261 without the heat conductive sheet 240.

[0041] The second electronic component 262, which is relatively less susceptible to heat generation, is spaced apart in the axial direction from the plate-shaped portion 51 of the cover 23. The second electronic component 262 includes, for example, an IC component. The lower end of the heat dissipation component 232 in this embodiment is located lower than the plate-shaped portion 51. This allows the first electronic component 261 to come into contact with the heat dissipation component 232 without the second electronic component 262 coming into contact with the cover main body portion 231.

[0042] As shown in FIG. 4, the heat dissipation component 232 has a fixing portion 72 provided on the outer side of the multiple fins 71 in the horizontal direction. The fixing portion 72 extends substantially perpendicular to the axial direction. However, the fixing portion 72 may be slightly inclined from the direction substantially perpendicular to the axial direction. When the cover 23 is resin-molded, the heat dissipation component 232 is fixed by covering a side surface 721 of the fixing portion 72 and a lower end surface 722 of the fixing portion 72 with the resin forming the cover body portion 231. This prevents the heat dissipation component 232 from coming off the cover body portion 231 in the axial direction. In addition, since the heat dissipation component 232 can be attached to the cover body portion 231 without using screws, adhesives, or the like, there is almost no gap between the heat dissipation component 232 and the cover body portion 231. Therefore, even if water is splashed on the cover 23 from the outside of the motor 1, it is possible to prevent the water from entering the inside of the motor 1. However, the side surface 721 of the fixing portion 72 and the upper end surface 723 of the fixing portion 72 of the heat dissipation component 232 may be covered by the resin forming the cover main body portion 231. That is, it is sufficient that the side surface 721 of the fixing portion 72 and at least a part of the upper end surface 723 and the lower end surface 722 of the fixing portion 72 are covered by the resin forming the cover main body portion 231 to be fixed.

[0043] As shown in FIG. 4, the heat dissipation component 232 further has an axial extension portion 73 extending in the axial direction below the multiple fins 71. Also, as shown in FIG. 5, the cover body portion 231 has a first protrusion portion 53. The first protrusion portion 53 protrudes downward from the plate-shaped portion 51 at the periphery of the hole portion 52. In this embodiment, the entire side surface of the axial extension portion 73 of the heat dissipation component 232 is covered with the resin forming the first protrusion portion 53. This increases the area of ​​the heat dissipation component 232 covered by the resin forming the cover body portion 231. As a result, even if the heat dissipation component 232 receives an external force, it is suppressed from tilting or falling. However, it is sufficient that at least a part of the side surface of the axial extension portion 73 of the heat dissipation component 232 is covered with the resin forming the cover body portion 231.

[0044] As shown in FIG. 3, a step portion 521 is formed on the periphery of the hole portion 52 in the upper end portion of the cover main body portion 231. The step portion 521 is recessed downward from the upper surface of the plate-shaped portion 51. The step portion 521 is wider in the direction perpendicular to the axial direction than other portions of the hole portion 52. The step portion 521 is provided with a lower portion of the fins 71 of the heat dissipation component 232 and the fixing portion 72. That is, the lower portion of the fins 71 of the heat dissipation component 232 is located in the hole portion 52, and the portion protruding upward from the cover main body portion 231 is reduced. This makes it possible to reduce the axial height of the motor 1. However, by providing the step portion 521 deeper, all of the fins 71 of the heat dissipation component 232 may be disposed in the hole portion 52.

[0045] FIG. 6 is a partial vertical cross-sectional view of the motor 1. As shown in FIG. 6, the upper bearing housing 251 has a cylindrical portion 91 and a flange portion 92. The cylindrical portion 91 extends cylindrically along the central axis 9. The upper bearing portion 61 is disposed inside the cylindrical portion 91. The flange portion 92 extends radially outward from the lower end of the cylindrical portion 91. The cover body 231 has a second protruding portion 54 having an annular shape. The second protruding portion 54 protrudes downward from the radially inner end of the plate-shaped portion 51. A circumferential portion of the second protruding portion 54 constitutes a part of the first protruding portion 53 described above. The flange portion 92 of the upper bearing housing 251 is covered with a resin that forms the second protruding portion 54.

[0046] This forms a structure in which a part of the cover body 231 made of resin, which is an insulator, is interposed between the upper bearing housing 251 and the upper bearing 61 and the heat dissipation component 232 and the electronic component 26. As a result, electrical insulation performance between the upper bearing housing 251 and the upper bearing 61 and the heat dissipation component 232 and the electronic component 26 is sufficiently ensured. Then, electricity flowing through the circuit board 24 on which the first electronic component 261 and the second electronic component 262 are mounted is suppressed from being transmitted to the shaft 31 via the heat dissipation component 232, the upper bearing housing 251, and the upper bearing 61. In particular, in this embodiment, the second protrusion 54 extending in the axial direction is interposed between the upper bearing housing 251 and the upper bearing 61 and the electronic component 26, thereby ensuring a longer insulation distance.

[0047] Furthermore, by resin molding the cover 23 having such a structure, it is possible to simultaneously form a structure capable of insulating the heat dissipation components 232 and electronic components 26 from the upper bearing portion 61, and the upper bearing housing portion 251 for holding the upper bearing portion 61. This allows the manufacturing process to be shortened. In this embodiment, the cylindrical portion 91 of the upper bearing housing portion 251 is located below the upper end portion of the motor 1. This allows the axial height of the motor 1 to be reduced while maintaining the fixing strength of the upper bearing housing portion 251 to the cover body portion 231.

[0048] As shown in FIG. 4, the fixing portion 72 of the heat dissipation component 232 forms a pedestal shape extending perpendicularly to the axial direction from the multiple fins 71. Also, as shown in FIG. 2, the upper end surface of the pedestal shape is an exposed surface 724 exposed from the cover body 231 to the outside of the motor 1. When the cover 23 is resin-molded, the peripheral portion of the multiple fins 71 is pressed from above by a mold to prevent the heat dissipation component 232 inserted into the cover 23 from floating up. As a result, after the resin molding, the peripheral portion of the multiple fins 71 becomes the exposed surface 724 exposed to the outside. When water is splashed on the cover 23 from the outside of the motor 1, the water is likely to accumulate on the exposed surface 724.

[0049] Therefore, in this embodiment, a groove 55 is further formed in the cover body 231. The groove 55 is recessed downward from a part of the upper end face of the cover body 231, and connects the outer circumferential face of the cover body 231 and the hole 52. The groove 55 is also continuous with the exposed face 724. As a result, even if water is splashed onto the cover 23 from outside the motor 1, it can be drained via the groove 55 without accumulating on the exposed face 724.

[0050] <2. Modifications> Although the exemplary embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0051] The upper bearing housing 251 and the lower bearing housing 252 may not be provided. For example, the upper bearing 61 may be directly fixed to the cover body 231 of the cover 23 without the upper bearing housing 251. That is, the cover 23 may be configured to directly or indirectly hold the upper bearing 61. Then, a part of the cover body 231 made of resin, which is an insulator, may be interposed between the upper bearing 61 and the heat dissipation component 232 at least in the radial direction. This ensures sufficient electrical insulation between the upper bearing 61 and the heat dissipation component 232 and the electronic component 26. The lower bearing 62 may be directly fixed to the bottom plate 222 of the casing 22 without the lower bearing housing 252. That is, the casing 22 may be configured to directly or indirectly hold the lower bearing 62.

[0052] FIG. 7 is a perspective view of the cover 23B and the upper bearing housing according to one modification, seen from above. In the example of FIG. 7, the surface 234B constituting the hole 52B of the cover main body 231B is inclined in a direction away from the radial center of the hole 52B as it goes upward. That is, the radial width of the hole 52B increases as it goes upward. This allows the air to flow smoothly from the outside of the motor 1 into the hole 52B and then out of the hole 52B to the outside of the motor 1. As a result, the heat dissipation performance of the heat dissipation component 232B is further improved.

[0053] Fig. 8 is a partial vertical cross-sectional view of a motor 1C according to another modified example. As shown in the example of Fig. 8, the fixing portion 72C of the heat dissipation component 232C may be slightly inclined with respect to the horizontal direction. Even in this case, the side surface 721C of the fixing portion 72C of the heat dissipation component 232C and at least a part of the upper end surface 723C and the lower end surface 722C of the fixing portion 72C are firmly fixed by being covered with the resin forming the cover main body portion 231C.

[0054] FIG. 9 is a partial vertical cross-sectional view of a motor 1D according to another modified example. In the example of FIG. 9, the heat dissipation component 232D has a plurality of fins 71D, a fixed portion 72D, and an axial extension portion 73D. The axial extension portion 73D extends in the axial direction below the plurality of fins 71D. The fixed portion 72D extends approximately perpendicular to the axial direction outside the lower end of the axial extension portion 73D. The heat dissipation component 232D is firmly fixed by covering a side surface 721D of the fixed portion 72D and an upper end surface 723D of the fixed portion 72D with the resin that forms the cover main body portion 231D. In addition, the heat dissipation component 232D having such a structure is prevented from coming off and falling off the cover 23D.

[0055] In addition, the detailed shape of each member may differ from the shape shown in each drawing of the present application. Furthermore, the elements appearing in the above-mentioned embodiment and modified examples may be appropriately combined to the extent that no contradiction occurs. [Industrial Applicability]

[0056] The present invention can be used in a motor. [Explanation of symbols]

[0057] 1,1C,1D motor 2 Stationary part 3 Rotating section 9 Center axis 21 Stator 22 Casing 23, 23B, 23D Cover 24 Circuit Board 25 Bearing storage section 26 Electronic Components 31 Shaft 32 Rotor 41 Coreback 42 Teeth 51 Plate-shaped part 52,52B Hole 53 1st protrusion 54 Second protrusion 55 Groove 60 Bearing section 61 Upper bearing part 62 Lower bearing part 71,71D fins 72,72C,72D Fixed part 73,73D Axial extension part 91 Cylindrical part 92 Flange 211 Stator core 212 Insulator 213 Coil 220 Interior Space 223 Casing opening 231, 231B, 231C, 231D Cover body 232, 232B, 232C, 232D Heat dissipation parts 240 Thermal Conductive Sheet 251 Upper bearing housing 252 Lower bearing housing 261 First Electronic Component 262 Second Electronic Parts 724 Exposed surface

Claims

1. A motor, A stationary portion; a rotating part that rotates around a central axis via a bearing part; having The stationary portion is A stator; a casing that accommodates at least a portion of the stator; a cover fixed to the casing and directly or indirectly holding the bearing portion; A circuit board extending in a radial direction and electrically connected to the stator; having The rotating part is A rotor, a shaft attached to the rotor and extending along the central axis; having The circuit board includes: Electronic components for driving the motor having the casing has an internal space that is open at least at a casing opening formed on one axial side and continues from the casing opening to the other axial side, the electronic component is located in the internal space, The cover covers the casing opening from one axial side of the circuit board, and A resin cover body; a heat dissipation component attached to the cover body and having a higher thermal conductivity than the cover body; having an end portion on the other axial side of the heat dissipation component contacts the electronic component directly or indirectly via a separate member; the cover body is interposed between the bearing portion and the heat dissipation component at least in a radial direction, The cover is A metallic bearing receiving portion fixed to the cover body portion and having the bearing portion disposed therein. and The cover body portion is Plate-like part that expands like a plate having The bearing housing portion is a cylindrical portion in which the bearing portion is disposed and which extends cylindrically along the central axis; a flange portion extending radially outward from the other axial end of the cylindrical portion; having The cover body portion is a second protruding portion protruding from a radially inner end portion of the plate-shaped portion toward the other axial side; and The flange portion is covered with a resin that forms the second protrusion portion.

2. 2. The motor according to claim 1, The cover body is interposed between the bearing housing portion and the heat dissipation component.

3. 3. The motor according to claim 2, The cover body portion is A hole that penetrates the plate-shaped portion in the axial direction and the heat dissipation component is disposed in the hole, and an end portion on the other axial direction side of the heat dissipation component is located on the other axial direction side of the plate-shaped portion, The electronic component includes a first electronic component and a second electronic component, the first electronic component is in contact with the heat dissipation component directly or indirectly via another member; The second electronic component is spaced apart from the plate-shaped portion.

4. 4. The motor according to claim 3, The heat dissipation component is Fixing part extending perpendicular to the axial direction having The heat dissipation component is fixed to the motor by covering the side surfaces of the fixed portion and at least a portion of the end faces on one axial side and the other axial side of the fixed portion with resin that forms the cover main body portion.

5. The motor according to claim 3 or claim 4, The heat dissipation component is A plurality of fins exposed to the outside of the motor and a motor in which some or all of the plurality of fins on the other axial side are positioned in the hole portion.

6. A motor according to any one of claims 3 to 5, The cover body portion is a first protruding portion protruding from the plate-shaped portion toward the other axial side at a peripheral edge of the hole; and At least a portion of a side surface of the heat dissipation component is covered with the resin that forms the first protrusion.

7. 4. The motor according to claim 3, The cylindrical portion is located on the other axial side of the one axial end of the motor.

8. A motor according to any one of claims 1 to 7, The heat dissipation component of the motor is made of metal.

9. A motor, A stationary portion; a rotating part that rotates around a central axis via a bearing part; having The stationary portion is A stator; a casing that accommodates at least a portion of the stator; a cover fixed to the casing and directly or indirectly holding the bearing portion; A circuit board extending in a radial direction and electrically connected to the stator; having The rotating part is A rotor; a shaft attached to the rotor and extending along the central axis; having The circuit board includes: Electronic components for driving the motor having the casing has an internal space that is open at least at a casing opening formed on one axial side and continues from the casing opening to the other axial side, the electronic component is located in the internal space, The cover covers the casing opening from one axial side of the circuit board, and A resin cover body; a heat dissipation component attached to the cover body and having a higher thermal conductivity than the cover body; having the other axial end of the heat dissipation component indirectly contacts the electronic component via a separate member; the cover body is interposed between the bearing portion and the heat dissipation component at least in a radial direction, The cover body portion is A plate-like portion that expands like a plate; a hole portion passing through the plate-shaped portion in an axial direction; having The cover body portion is a first protruding portion protruding from the plate-shaped portion toward the other axial side at a peripheral edge of the hole; and At least a portion of a side surface of the heat dissipation component is covered with a resin that forms the first protrusion, At least a portion of the end portion on the other axial side of the first protrusion contacts the separate member.

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