CN117099292A

CN117099292A - Motor with a motor housing having a motor housing with a motor housing

Info

Publication number: CN117099292A
Application number: CN202280023581.3A
Authority: CN
Inventors: 池田雅寿; 索姆猜·斯里蓬潘库尔; 帕塔拉瓦迪·法布通
Original assignee: Fujitsu General Ltd
Current assignee: Fujitsu General Ltd
Priority date: 2021-03-29
Filing date: 2022-03-11
Publication date: 2023-11-21
Also published as: JP2022152646A; JP7255622B2; WO2022209765A1

Abstract

The invention provides a motor capable of realizing miniaturization of the motor in the axial direction and ensuring insulation between a circuit substrate and a radiator. To this end, an electric motor according to an embodiment of the present invention includes: a heat sink covering an open end of the outer contour of the cylindrical resin; a circuit board disposed in an inner space covered by the resin outer contour and the heat sink; and a heat transfer member disposed between the heat sink and the circuit board and having electrical insulation properties. The heat sink includes: a disk portion which is in contact with the opening end portion of the resin outer contour; an annular projection portion projecting from the disk portion toward the circuit board side in the axial direction; and a projection portion disposed on an inner diameter side of the annular projection portion and projecting from the disk portion toward the electronic component. The heat transfer member includes: a heat transfer portion sandwiched between the electronic component and the protruding portion; and a peripheral edge portion provided outside the heat transfer portion and located outside an outer peripheral edge of the electronic component as viewed in the axial direction.

Description

Motor with a motor housing having a motor housing with a motor housing

Technical Field

The present invention relates to motors, and more particularly to an insulating structure of a circuit board incorporated in a motor.

Background

Conventionally, a motor having a circuit board for controlling rotation driving of the motor inside the motor is known. Further, a motor having a heat sink for dissipating heat generated by the electronic component that generates heat to the outside of the motor is also known.

For example, patent document 1 describes a brushless motor having the following structure: resin, mold the stator core; a metal bracket for supporting a bearing on the opposite side of the motor and mounted on the end of the resin on the opposite side of the motor; a heat sink (heat sink) fixed to an end of the resin via the metal bracket and including a protrusion portion capable of being inserted into a hole portion provided in an outer surface of the metal bracket; and a circuit board disposed inside the motor, wherein the protruding portion is brought into contact with an electronic component on the circuit board via a heat conductive resin.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2009-131127

Disclosure of Invention

Problems to be solved by the invention

In patent document 1, heat generated by an electronic component on a circuit board is transferred to a heat sink serving as a heat sink via a heat conductive resin, and is discharged to the outside of a motor. In this motor, a metal member (heat sink) is used in a portion (hereinafter referred to as a "contactable portion") exposed to the outside of the motor that can be contacted by a user. In such a case, in general, by electrically connecting the metal member exposed to the outside with a ground (ground), discharge of a conductive portion (hereinafter referred to as a "charging portion") to which a voltage is applied from the inside of the motor to the metal member as a contactable portion is prevented.

On the other hand, in a motor in which a heat sink (metal member) is disposed in a contactable portion, the heat sink may not be electrically connected to a ground (i.e., a protective ground is not provided). In this case, in terms of safety standards, it is necessary to secure a sufficient insulation distance (spatial distance and creepage distance) between the charging portion (e.g., circuit board) inside the motor and the conductive portion (e.g., heat sink) of the contactable portion. The spatial distance is the shortest distance between the charging portion (e.g., circuit board) and the contactable portion (e.g., heat sink) through the space. The creepage distance is the shortest distance measured along the surface of the insulator (e.g., the surface of the heat conductive resin) between the charging portion (e.g., the circuit board) and the contactable portion (e.g., the heat sink).

For example, in the structure of patent document 1, if it is assumed that the protective ground is not provided, it is conceivable to increase the distance between the substrate and the bracket and to increase the thickness of the heat conductive resin in the upward direction of the rotation axis of the motor, thereby securing the insulation distance between the circuit substrate and the heat sink. However, for this reason, there is a problem in that miniaturization of the motor in the rotation axis direction becomes difficult.

In view of the above, an object of the present invention is to provide a motor capable of achieving miniaturization in the axial direction of the motor and ensuring insulation between a circuit board and a heat sink.

Means for solving the problems

In order to achieve the above object, an electric motor according to an embodiment of the present invention includes: resin outer contour, stator, rotor, radiator, circuit substrate and heat transfer component. The resin outer contour is formed in a cylindrical shape and has an open end portion at one end side in the axial direction. The stator includes a coil and a stator core. The coil and the stator core are integrally formed with the resin outer contour. The rotor is disposed on an inner diameter side of the stator core. The heat sink covers the open end of the resin outer contour. The circuit board has an electronic component and is disposed in an internal space covered by the resin outer contour and the heat sink. The heat transfer member has electrical insulation properties and is disposed between the heat sink and the electronic component. The heat sink includes a disk portion, an annular protruding portion, and a protruding portion. The circular plate portion is in contact with the opening end portion of the resin outer contour. The annular projection projects from the circular plate portion toward the circuit board side in the axial direction. The projection is formed to project from the disk portion toward the electronic component, and is disposed on an inner diameter side of the annular projection. The heat transfer member has a heat transfer portion and a peripheral portion. The heat transfer portion is sandwiched between the electronic component and the protruding portion. The peripheral edge part is arranged outside the heat transfer part and is positioned outside the outer peripheral edge of the electronic component when viewed in the axial direction

According to the motor, the heat transfer member is sandwiched between the electronic component and the protruding portion. The peripheral edge portion of the heat transfer member is disposed outside the outer peripheral edge of the electronic component as viewed from the protruding portion. Thereby, the peripheral edge portion of the heat transfer portion covers the electronic component as viewed from the protruding portion. Therefore, the insulating distance (the space distance and the creepage distance) between the electronic component and the protruding portion can be ensured in the direction orthogonal to the protruding portion. Therefore, the thickness of the heat transfer member in the axial direction can be reduced, and the motor can be miniaturized in the axial direction.

The protruding portion may have a greater protruding height from the disk portion than the annular protruding portion.

The projection may have an inclined portion in which the cross-sectional area of the projection perpendicular to the axial direction becomes smaller as the cross-sectional area goes from the disk portion toward the electronic component.

The projection may have an opposing surface opposing the electronic component, and an area of the opposing surface may be smaller than an area of the electronic component when viewed in the axial direction.

The peripheral edge portion of the electronic component may include a lead portion, and the peripheral edge portion of the heat transfer member may include an edge portion located on a path where a distance between the lead portion and the annular protruding portion becomes the shortest distance.

Effects of the invention

According to the present invention, it is possible to provide a motor capable of achieving miniaturization in the axial direction of the motor and ensuring insulation between the circuit board and the heat sink.

Drawings

Fig. 1 is a cross-sectional view of an electric motor according to a first embodiment of the present invention.

Fig. 2 is a perspective view of the outer contour of the resin in the motor.

Fig. 3 is a perspective view of the heat sink in the motor, (a) is a front perspective view, and (B) is a rear perspective view.

Fig. 4 is a diagram showing a main portion of a motor according to a first embodiment of the present invention, (a) is a side sectional view showing a main portion of a connection portion between a protrusion portion of a heat sink and an electronic component, and (B) is a plan view of the electronic component viewed from the heat sink side.

Fig. 5 is a side sectional view illustrating an insulation distance between a protrusion of a heat sink and an electronic component.

Fig. 6 is a general explanatory view of the insulation distance.

Fig. 7 is a cross-sectional view of a main part of an electric motor according to a second embodiment of the present invention, wherein (a) is a view showing a spatial distance, and (B) is a view showing a planar distance.

Detailed Description

Next, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are denoted by the same or similar symbols. It should be noted, however, that the drawings are schematic and may differ from reality. Therefore, regarding specific constituent elements, the following description should be referred to for judgment.

The embodiments described below are embodiments illustrating an apparatus and a method for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the following shapes, structures, arrangements, and the like of constituent members. The technical idea of the present invention can be variously modified within the technical scope defined in the claims.

< first embodiment >, first embodiment

Fig. 1 is a cross-sectional view of a motor 1 according to a first embodiment. The motor 1 of the present embodiment is used as a rotational drive source for a blower fan mounted in an indoor unit of an air conditioner, for example.

[ Integrated Structure of Motor ]

The motor 1 includes a stator core 21, a rotor 3, a resin outer contour 10, a first bearing 71, a second bearing 81, a heat sink 4, and a circuit board 5.

The stator core 2 is integrally formed with the resin outer contour 10.

The rotor 3 is fixed to the rotary shaft 6 and disposed on the inner diameter side of the stator core 2.

The resin outer contour 10 is a cylindrical shape having an opening end 101 at one end in a direction parallel to the axial center C of the rotary shaft 6 (hereinafter also referred to as an axial direction).

The heat sink 4 is disposed to cover the open end 101 of the resin outer contour 10.

The circuit board 5 is disposed in the inner space covered by the resin outer contour 10 and the heat sink 4.

Hereinafter, as an example, an inner rotor type brushless DC motor in which a cylindrical rotor 3 having a permanent magnet portion 31 is rotatably disposed inside a cylindrical stator 2 that generates a rotating magnetic field in the radial direction will be described as an electric motor 1. The motor 1 is not limited to this, and may be, for example, another motor such as an outer rotor type brushless DC motor or an AC motor.

In the following description, the axial center C of the rotary shaft 6 is also the central axis of the motor 1, that is, the rotary shaft of the rotor 3. The radial direction refers to a direction passing through the axial center C and orthogonal to the axial direction. The inner diameter side means the inner side in the radial direction, and the outer diameter side means the outer side in the radial direction. The circumferential direction refers to a rotation direction around the axis C.

(rotor)

The rotor 3 includes a ring-shaped permanent magnet portion 31 and a rotor body 30. The rotor body 30 has an outer peripheral surface and an inner peripheral surface. Permanent magnet portion 31 is fixed to the outer peripheral surface of rotor body 30. The rotary shaft 6 is fixed to the inner peripheral surface of the rotor body 30. Thereby, the rotary shaft 6 is rotationally driven integrally with the rotor body 30.

The rotor 3 is a surface magnet type in which a permanent magnet portion 31 is annularly fixed to the outer peripheral surface. The permanent magnet portion 31 is formed in a ring shape from a plurality of (e.g., 8 or 10) permanent magnets so that N poles and S poles alternate at equal intervals in the circumferential direction. The permanent magnet portion 31 is typically formed of a sintered metal such as nd—fe—b alloy, but other than this, a plastic magnet formed in a ring shape by fixing a magnet powder with a resin may be used.

As shown in fig. 1, the rotor body 30 includes an outer peripheral side core 32, an insulating member 33, and an inner peripheral side core 34.

The outer core 32 is formed in a ring shape, and forms the outer peripheral surface of the rotor body 30. The outer core 32 is a laminate of plates made of a soft magnetic material such as a plurality of electromagnetic steel plates. The inner core 34 is formed in a ring shape, and forms an inner peripheral surface of the rotor body 30.

The inner core 34 is a laminate of plates made of a soft magnetic material such as a plurality of electromagnetic steel plates. The rotary shaft 6 is fixed to the center of the inner core 34 by press fitting, caulking, or the like.

The insulating member 33 electrically insulates the outer-periphery-side core 32 from the inner-periphery-side core 34. This reduces the difference between the capacitance on the stator side and the capacitance on the rotor side of the motor 1, thereby suppressing the electrolytic corrosion of the bearings 71 and 81. The insulating member 33 is made of a resin having a dielectric such as PBT (polybutylene terephthalate) or PET (polyethylene terephthalate), and is fixed between the outer core 32 and the inner core 34. The insulating member 33 may be a ring-shaped molded body, or may be a resin material filled between the outer peripheral side core 32 and the inner peripheral side core 34 by insert molding or the like.

(stator)

The stator 2 includes: a stator core 21 having a cylindrical yoke portion and a plurality of teeth extending from the yoke portion to an inner diameter side; a winding (coil) 22 wound around the tooth. The stator core 21 is a laminate of plates made of a soft magnetic material such as a plurality of electromagnetic steel plates, for example. The outer peripheral surface of the stator 2 (stator core 21) is covered with a resin outer contour 10 (see fig. 1). The stator 2 is arranged so that the permanent magnet portion 31 of the rotor 3 faces the stator core 21 of the stator 2 with a gap (magnetic gap) therebetween in the radial direction.

(outer contour of resin)

The resin outer contour 10 is made of an insulating resin material. Fig. 2 is a perspective view of the resin outer contour 10 of the motor 1, and is formed in a hollow cylindrical shape having an opening end 101 on one axial end side (in the present embodiment, the opposite output end 61 side of the rotary shaft 6) as shown in fig. 2. Here, the opposite output end 61 refers to an end of the rotary shaft 6 opposite to the output end 62. The output end 62 is an end on the load side (side connected to a load) of the motor 1.

As described above, the resin outer contour 10 is integrally molded with the stator 2. The resin material constituting the resin outer contour 10 is not particularly limited, and is formed of, for example, BMC (Bulk Molding Compound: unsaturated polyester resin) resin.

The resin outer contour 10 has a mounting surface 9. The mounting surface 9 is a plane formed on the inner peripheral surface 10a side of the resin outer contour 10 and perpendicular to the axial direction, and is provided on the opposite output end 61 side of the rotary shaft 6 in the axial direction from the rotor 3. The mounting surface 9 supports a circuit board 5 described later. In the present embodiment, the placement surface 9 is a surface on the opposite output end portion 61 side of the stepped portion provided so as to protrude from the inner peripheral surface 10a of the resin outer contour 10 toward the inner diameter side. The mounting surface 9 may be formed continuously along the circumferential direction of the inner peripheral surface 10a of the resin outer contour 10, or may be formed at a plurality of positions with a space therebetween along the circumferential direction.

The resin outer contour 10 further includes a second bearing housing 82 that houses a second bearing 81 described later. The second bearing housing 82 is substantially cylindrical with one end thereof being blocked around the axial center C. The second bearing housing 82 is provided at the bottom 102 of the resin outer contour 10 opposite to the open end 101.

(Circuit Board)

The circuit board 5 includes a wiring board 50 and an electronic component 51 mounted on the surface of the wiring board 50 (the surface on the opposite output end 61 side of the rotary shaft 6) and generating heat by energization. The circuit board 5 has a substantially disk shape, and the peripheral edge portion of the circuit board 5 is supported on the mounting surface 9 and fixed by, for example, adhesion, bonding, screw fastening, welding, or the like. Further, a convex portion for positioning may be provided at the peripheral edge portion of the circuit board 5, and a concave portion for positioning that engages with the convex portion may be provided at the inner peripheral surface 10a of the resin outer contour 10, whereby the circuit board 5 can be fixed to the mounting surface 9 in a state of being positioned in the circumferential direction.

The electronic component 51 includes a component main body 51, and lead portions 511 extending from 2 opposite sides of the component main body 51. The lead portion 511 is not limited to extending from 2 sides of the component main body 51, and may extend from only 1 side or may extend from 4 sides. The component main body 51 is a package made of synthetic resin and having a semiconductor element incorporated therein. The lead portion 511 is composed of a plurality of metal external terminals electrically connected to the wiring board 50, and forms at least a part of the outer periphery of the electronic component 51. The electronic component 51 is mainly a semiconductor package component such as a power supply IC or an IC for controlling a motor drive current, and may be a passive component such as a capacitor.

Further, other components such as a connector component connected to a power cable are mounted on the wiring board 50 in addition to the electronic component 51, but these components are not shown. The power cable is connected to a power source, not shown, through a cable insertion portion 105 formed in the vicinity of the opening end portion 101 of the resin outer profile 10 and extending over a predetermined angular range in the circumferential direction thereof.

As shown in fig. 2, a plurality of (2 in this example) positioning pins 9c penetrating the circuit board 5 are provided on the mounting surface 9.

Further, the positioning concave portion 104 for accommodating the circuit board 5 may be partially provided on the inner peripheral surface 10a of the resin outer contour 10, whereby the circuit board 5 can be fixed to the mounting surface 9 in a state of being positioned in the circumferential direction.

The end 221 of the coil 22 shown in fig. 2 is electrically connected to the circuit board 5, and the circuit board 5 is positioned on the mounting surface 9 by a plurality of positioning pins 9c and is fixed to the mounting surface 9 by soldering the circuit board 5 and the end 221 of the coil.

(bearing)

As shown in fig. 1, the first bearing 71 is a ball bearing having an outer race 711, an inner race 712, a plurality of balls 713, and the like. The second bearing 81 is a ball bearing having an outer race 811, an inner race 812, balls 813, and the like.

The outer ring 711 of the first bearing 71 is fixed to the heat sink 4 (first bearing housing 41), and the inner ring 712 of the first bearing 71 is fixed to the output opposite end portion 61 side of the rotary shaft 6. The outer ring 813 of the second bearing 81 is fixed to the resin outer contour 10 (second bearing housing 82), and the inner ring 812 of the second bearing 81 is fixed to the output end 62 of the rotary shaft 6. Thereby, the rotation shaft 6 is supported by the first bearing 71 and the second bearing 81 so as to be rotatable about the axis C with respect to the radiator 4 and the resin outer contour 10.

(radiator)

The heat sink 4 includes a first bearing housing portion 41, a disk portion 42, an annular protruding portion 43, and a protruding portion 44. The heat sink 4 is mounted and fixed to the open end 101 of the resin outer profile 10. The heat sink 4 is made of a metal material having excellent heat conductivity such as aluminum. The heat sink 4 is integrally formed with a circular plate portion 42, an annular protruding portion 43, and a protruding portion 44, respectively. The heat sink 4 is molded by, for example, die casting (casting).

The heat sink 4 has a function as a cover member (bracket) for closing the inside of the resin outer contour 10 by covering the open end 101 of the resin outer contour 10, a function as a bearing housing (bearing housing) for supporting the first bearing 71, and a function as a heat radiating member for radiating heat generated by the electronic component 51 inside the motor to the outside of the motor. The heat sink 4 is fixed to the open end 101 of the resin outer contour 10 using a plurality of screw members, not shown.

Fig. 3 (a) is a perspective view of the inner surface side (lower surface side in fig. 1) of the heat sink 4, and fig. 3 (B) is a perspective view of the outer surface side (upper surface side in fig. 1) of the heat sink 4.

The circular plate portion 42 is an annular plate portion having a center hole 40 centered on the axis C. In the present embodiment, the outer diameter of the disk portion 42 is the same as or substantially the same as the outer diameter of the opening end portion 101 of the resin outer contour 10. As shown in fig. 3 (a) and (B), the disk portion 42 has an upper surface 423 and a rear surface 424 opposite thereto. As described later, the first bearing housing 41 is formed on the upper surface portion 423 of the disk portion 42. An axial positioning portion 420, an annular protruding portion 43, and a protruding portion 44 are provided on the back surface 424 of the disk portion 42.

The annular protruding portion 43 is formed to protrude from the back surface 424 side of the disk portion 42 toward the circuit board 5 side. The annular projection 43 has a radial positioning portion 430 that abuts against the inner peripheral surface 10a of the resin outer contour 10.

The protrusion 44 is disposed on the inner diameter side of the annular protrusion 43, protrudes from the back surface 424 side of the disk 42 toward the circuit board 5 side, and thermally contacts the circuit board 5 (the electronic component 51 in the present embodiment). In the present embodiment, as shown in fig. 1, when the heat sink 4 is mounted on the resin outer contour 10, the protruding portion 44 is formed so as to face the electronic component 51 in a region arranged between the first bearing housing portion 41 and the annular protruding portion 43 in the radial direction.

Details of each part will be described below.

(first bearing housing part)

The first bearing housing 41 houses the first bearing 71. The first bearing housing portion 41 has a cylindrical shape with one end thereof being closed with the axis C as the center, and houses the first bearing 71. The first bearing housing portion 41 is formed on the upper surface 423 side of the inner peripheral portion 401 of the center hole 40 of the circular plate portion 42.

(circular plate portion)

The circular plate portion 42 has an axial positioning portion 420. As shown in fig. 3 (a), the axial positioning portion 420 is formed on the back surface 424 side of the outer peripheral edge portion 422 of the disk portion 42. In the present embodiment, the outer peripheral edge 422 refers to an area of the disk 42 on the outer diameter side of the annular protruding portion 43.

The disk portion 42 in the region on the inner diameter side of the outer peripheral edge portion 422 may have a smaller thickness in the axial direction than the outer peripheral edge portion 422. When the thickness of the disk portion 42 in the region on the inner diameter side of the outer peripheral edge portion 422 is made thinner than the outer peripheral edge portion 422, as shown in fig. 3 (a), a plurality of ribs 425 may be provided on the back surface 424 side of the disk portion 42. The plurality of ribs 425 are formed radially from the first bearing housing 41 toward the annular protruding portion 43. By providing the plurality of ribs 425, the strength of the heat sink 4 can be ensured.

The axial positioning portion 420 is formed on the back surface 424 side of the outer peripheral edge portion 422, and abuts against the opening end portion 101 of the resin outer contour 10. As shown in fig. 1, the axial positioning portion 420 faces the opening end portion 101 in the direction of the axial center C. As shown in fig. 3 (a), the axial positioning portion 420 is formed by a plane orthogonal to the axial center C throughout the entire rear surface 424 side of the outer peripheral edge portion 422. For example, the axial positioning portion 420 of the heat sink 4 may have an annular protruding portion protruding toward the opening end portion 101, or may have an annular groove portion corresponding to the protruding portion at the opening end portion 101 of the resin outer contour 10. The cross section of the protruding portion as viewed in the radial direction may be trapezoidal or curved.

As shown in fig. 3 (a) and (B), holes 421 through which screws are inserted are formed at a plurality of positions on the outer peripheral edge 422 of the disk 42. In the present embodiment, the hole 421 is provided at 3 positions at equal angular intervals in the outer peripheral edge 422. The number and positions of the holes 421 provided in the outer peripheral edge 422 may be changed as appropriate, and the holes 421 may not be provided in the outer peripheral edge 422. In the present embodiment, a screw receiving portion, not shown, is formed at a position facing the hole 421 at the opening end 101 of the resin outer contour 10. The heat sink 4 is fixed to the open end 101 of the resin outer contour 10 by a plurality of screws inserted through the holes 421. At this time, the heat sink 4 is positioned in its circumferential direction with respect to the open end 101 of the resin outer contour 10.

The circular plate portion 42 further has a cutout portion 426 formed in a part of the peripheral edge portion 422 thereof over a predetermined angular range. The notch 426 is provided at a position corresponding to the cable insertion portion formed in the vicinity of the opening end 101 of the resin outer profile 10. Thus, when the radiator 4 is assembled to the opening end 101 of the resin outer contour 10, the notch 426 can be used as a mark for positioning with respect to the circumferential direction of the resin outer contour 10.

(annular protruding portion)

As described above, the annular projection 43 has the radial positioning portion 430. In the present embodiment, the radial positioning portion 430 is formed on the outer peripheral surface of the annular protruding portion 43 that abuts the inner peripheral surface of the opening end portion 101 of the resin outer contour 10. That is, as shown in fig. 1, 2, and 3 (a), the radial positioning portion 430 has a cylindrical surface fitted to the inner peripheral surface 10a of the resin outer contour 10.

As shown in fig. 3 (a), the annular protruding portion 43 is formed in an annular shape centering around the axis C on the back surface 424 of the disk portion 42. As shown in fig. 1, the annular projection 43 has a substantially rectangular cross section parallel to the axis C. As shown in fig. 3 (a), the annular projection 43 is continuously formed in the circumferential direction without interruption, but the present invention is not limited thereto, and may be partially interrupted.

(protruding portion)

As described above, the protrusion 44 is disposed on the inner diameter side of the annular protrusion 43, and protrudes from the back surface 424 of the disk 42 toward the circuit board 5 in the axial direction.

As shown in fig. 3 (a), in the present embodiment, the projection 44 is a rectangular parallelepiped block projecting toward the electronic component 51 mounted on the circuit board 5. Further, the projection 44 has an opposing surface 441 opposing the electronic component 51. The shape of the protrusion 44 is not limited to a rectangular parallelepiped shape, and may be a cylindrical shape, for example.

As shown in fig. 1, the protruding height of the protruding portion 44 in the axial direction is preferably formed to be larger than the protruding height of the annular protruding portion 43. The protruding height here refers to a height protruding toward the circuit board side in the axial direction with reference to the back surface 424 of the disk portion 42. In the present embodiment, the facing surface 441 of the protruding portion 44 is located closer to the circuit board 5 than the axial tip portion of the annular protruding portion 43. The protruding height of the protruding portion 44 is set so that when the axial positioning portion 420 of the disk portion 42 is in contact with the opening end portion 101 of the resin outer contour 10, a gap of a predetermined range is formed between the opposing surface 441 of the protruding portion 44 and the upper surface of the electronic component 51.

The shape of the opposing surface 441 as viewed from the electronic component 51 side may be formed in accordance with the shape of the electronic component 51, for example, a quadrangular plane (see fig. 3 a). The opposing surface 441 has an area smaller than that of the electronic component 51 as viewed in the axial direction. The facing surface 441 may be formed into a flat surface by a lathe or the like after the heat sink 4 is molded by die casting or the like. In this case, since the protruding height of the protruding portion 44 in the axial direction is formed to be larger than the protruding height of the annular protruding portion 43, the annular protruding portion 43 can be prevented from becoming an obstacle when the facing surface 441 is processed by a lathe or the like. Thus, the axial height of the axial positioning portion 420 and the facing surface 441 of the radiator 4 can be set to appropriate dimensions, and even when the radiator 4 is molded by die casting (casting), dimensional variations and assembly variations in the axial direction of the radiator 4 can be suppressed.

Fig. 4 (a) is an enlarged view showing a connection portion between the protruding portion 44 and the electronic component 51 in fig. 1. Fig. 4 (B) is a schematic plan view of the electronic component 51 as viewed from the projection 44.

As shown in fig. 4 (a), a heat transfer member 52 and an adhesive member 53 are disposed between the electronic component 51 and the protrusion 44 in this order from the electronic component 51 side.

The heat transfer member 52 is preferably a member having good heat conductivity and high insulation, and is made of, for example, a heat sink made of silicone. The adhesive member 53 is also preferably a member having good heat conductivity and high insulation, and for example, an adhesive made of silicone resin is used.

In the present embodiment, an adhesive member 53 is provided between the protrusion 44 and the heat transfer member 52, and the facing surface 441 of the protrusion 44 is in thermal contact with the electronic component 51 via the heat transfer member 52 and the adhesive member 53. The present invention is not limited to this, and the protrusion 44 may directly contact the heat transfer member 52.

The adhesive member 52 not only adheres the heat transfer member 52 to the protruding portion 44, but also absorbs the positional deviation between the protruding portion 44 and the electronic component 51 in the axial direction by deformation of the adhesive member 52. Further, when the heat sink 4 is fitted to the resin outer contour 10, the adhesive member 53 deforms the adhesive member 52, thereby releasing the pressing force from the protrusion 44 to the electronic component 51. This ensures stable thermal connection between the protruding portion 44 and the electronic component 51, thereby improving heat transfer properties, and prevents breakage of the electronic component 51 and the circuit board 5 due to a force applied in the axial direction from the protruding portion 44.

The distance between the facing surface 441 and the electronic component 51 is set to be equal to or less than the total thickness of the heat transfer member 52 and the thickness of the adhesive member 53. This allows the opposing surface 441 to be in stable contact with the upper surface of the electronic component 51 via the heat transfer member 52 and the adhesive member 53. That is, the heat transfer between the facing surface 441 and the electronic component 51 can be improved.

In the present embodiment, as shown in fig. 4 (a), a narrowed portion 442 is further provided around the opposing surface 441 of the protruding portion 44. The narrowed portion 442 is formed by a step 443 formed around the protrusion 44 on the opposite surface 441 side. When the protrusion 44 is pressed against the adhesive member 53, the narrowed portion 442 withdraws a part of the adhesive member 53 that overflows to the outside of the protrusion 44 toward the outer peripheral surface side of the narrowed portion 442. Accordingly, since the protrusion 44 is in stable contact with the heat transfer member 52, the adhesive strength and heat transfer property between the protrusion 44 and the heat transfer member 52 can be improved.

(Heat transfer Member)

Next, details of the heat transfer member 52 will be described. As shown in fig. 4 (B), the heat transfer member 52 is formed in a substantially square shape having a size capable of covering the entire electronic component 51 when viewed from the axial direction. The heat transfer member 52 has 3 areas, i.e., a heat transfer portion 521, an intermediate portion 522, and a peripheral portion 523 in a plan view.

The heat transfer portion 521 is a region located at the substantially center of the heat transfer member 52 and sandwiched between the electronic component 51 and the facing surface 441 of the protrusion 44. The heat transfer portion 521 forms a heat transfer path between the protruding portion 44 and the electronic part 51. The intermediate portion 522 is a substantially rectangular and annular region located between the heat transfer portion 521 and the peripheral portion 523.

The peripheral portion 523 is a rectangular annular region located outside the heat transfer portion 521 and located outside the outer peripheral edge L of the electronic component 51 as viewed in the axial direction. The peripheral portion 523 may or may not be in contact with the lead portion 511 of the electronic component 51. The outer peripheral edge L of the electronic component 51 is a boundary portion of an area occupied by the entire electronic component 51 when viewed from the axial direction, and in the present embodiment, is a virtual rectangular frame surrounding the component main body 510 and the lead portion 511 forming the outer shape of the electronic component, as shown in fig. 4 (B).

The peripheral portion 523 of the heat transfer member 52 includes an eave portion 524. The brim portion 524 is a part of the peripheral portion 523, and is located on a path where a distance between the lead portion 511 of the electronic component 51 and the annular protruding portion 43 of the heat sink 4 becomes the shortest distance, as shown in fig. 4 (a). The formation range of the eave portion 524 is not particularly limited as long as the spatial distance between the annular protruding portion 43 and the wire portion 511 extending from the side surface of the component body 510 located on the annular protruding portion 43 side can be increased.

[ function of radiator ]

As described above, the heat sink 4 of the present embodiment includes: an axial positioning portion 420 that abuts against the open end 101 of the resin outer contour 10; and a radial positioning portion 430 that abuts the inner peripheral surface of the opening end portion 101 of the resin outer contour 10. Therefore, the heat sink 4 is positioned in both the axial direction and the radial direction with respect to the resin outer contour 10 while the heat sink 4 is assembled to the resin outer contour 10.

More specifically, the heat sink 4 is provided with an axial positioning portion 420 for positioning the relative position of the heat sink 4 with respect to the axial direction of the resin outer contour 10, and an opposing surface 441 of the protrusion 44 for positioning the relative position of the heat sink 4 with respect to the axial direction of the electronic component 51 of the circuit board 5. Therefore, the accuracy of the relative position of the heat sink 4 with respect to the axial direction of the resin outer contour 10 can be ensured. This suppresses the deviation (dimensional deviation, assembly deviation) of the relative positions of the opposing surface 441 of the protruding portion 44 and the axial direction of the electronic component 51, and enables stable heat transfer from the electronic component 51 to the protruding portion 44, thereby sufficiently dissipating heat to the outside of the motor 1.

For example, even when the heat sink 4 is formed by die casting with a large dimensional deviation, the dimensional deviation in the axial direction of the heat sink 4 can be reduced by performing the end surface treatment on the axial positioning portion 420 and the facing surface 441 in the subsequent step using a lathe. Therefore, the deviation (assembly deviation) of the relative positions of the opposing surface 441 of the protrusion 44 and the axial direction of the electronic component 51 can be further suppressed, and heat can be stably transferred from the electronic component 51 to the heat sink 4, thereby sufficiently dissipating heat to the outside of the motor 1.

Further, by forming the radial positioning portion 430 in the heat sink 4, the radial assembly variation between the heat sink 4 and the resin outer contour 10 can be reduced. Therefore, the facing surface 441 of the protrusion 44 of the heat sink 4 can be made to face the electronic component 51 fixed to the circuit board 5 of the resin outer contour 10 with high accuracy in the axial direction. The first bearing 71 can be disposed coaxially with the axis C with high accuracy.

According to the present embodiment, the heat sink 4 can be directly assembled to the resin outer contour 10 without requiring a separate support member for positioning between the heat sink 4 and the open end 101 of the resin outer contour 10. As a result, compared to the case where the heat sink is fixed to the end portion of the resin outer contour via the metal bracket supporting the bearing as described in patent document 1, for example, not only the reduction in the number of components and the improvement in the workability of assembly can be achieved, but also the accuracy of positioning the heat sink with respect to the resin outer contour can be improved.

That is, when other members such as the metal brackets are interposed between the outer resin contour and the radiator (fin), variations in the relative positions in the axial direction and the radial direction between the radiator and the outer resin contour are easily caused by variations in the dimensions of the metal brackets and the radiator itself, variations in the assembly of the outer resin contour and the metal brackets, and variations in the assembly of the metal brackets and the radiator. Therefore, the heat transfer characteristics may be unstable because the distance between the circuit board and the protrusion of the heat sink varies.

In contrast, according to the present embodiment, the heat sink 4 is directly assembled to the opening end portion 101 of the resin outer contour 10 without sandwiching the metal bracket, so that the influence of various variations of the metal bracket can be reduced, and the protruding portion 44 of the heat sink 4 can be positioned with high accuracy with respect to the circuit board 5 (electronic component 51). This ensures stable heat transfer characteristics between the heat sink 4 and the circuit board 5 (electronic component 51).

Further, according to the present embodiment, since the heat sink 4 includes the bearing housing 41, the first bearing 71 can be supported without the metal bracket. This can reduce the number of components and improve the workability of assembling the motor 1.

[ action of Heat transfer Member ]

As described above, the heat transfer member 52 of the present embodiment includes: a heat transfer portion 521 sandwiched by the electronic component 51 and the facing surface 441 of the protrusion 44; and a peripheral portion 523 provided outside the heat transfer portion 521 and located outside the outer peripheral edge L of the electronic component 51 as viewed from the axial direction. Therefore, the heat transfer member 52 covers the electronic component 51 on the upper surface side as viewed from the protruding portion 44. The heat transfer member 52 covers the upper surface side of the electronic component 51 when viewed from the protrusion 44, and thus a sufficient insulation distance (spatial distance, creepage distance) between the lead 511 of the electronic component 51 and the protrusion 44 can be ensured.

Here, the spatial distance refers to the shortest distance of the passing space between 2 conductive members (charging portion and contactable portion). The creepage distance is the shortest distance between 2 conductive members (charging unit and contactable unit) along the surface of the insulator. The charging unit is a conductive member to which a voltage is applied inside the motor. In the present embodiment, the electronic component 51 having the metal wire portion 511 is provided as the charging portion. The contactable portion is a member that is exposed to the outside of the motor and is accessible to a user. In the present embodiment, the cover member 4 formed of a conductive member is provided as the contactable portion. The insulation distance refers to a generic term for both the spatial distance and the creepage distance.

Here, the spatial distance a and the creepage distance B will be described with reference to fig. 5.

The space distance a is the shortest distance between the wire portion 511 and the protrusion 44, which are metal portions of the electronic component 51, and the space. In the present embodiment, the spatial distance a is the sum of the distance constituted by one straight line from the lead portion 511 to the peripheral portion 523 of the heat transfer member 52 and the distance constituted by one straight line from the peripheral portion 523 of the heat transfer member 52 to the protrusion 44. As shown in fig. 5, the surface distance B is the shortest distance between the wire portion 511 and the protrusion 44, which are metal portions of the electronic component 51 measured along the surface of the heat transfer member 52. In the present embodiment, the surface distance B is a distance from the wire portion 511 to the protrusion 44 along each surface in the order of the component main body 510, the heat transfer member 52, and the adhesive member 53 of the electronic component 51.

According to the motor 1 of the present embodiment, since the peripheral edge portion 523 of the heat transfer member 52 is located outside the outer peripheral edge L of the electronic component 51, the insulation distance (the spatial distance a, the surface distance B) between the lead portion 511 of the electronic component 51 as the charging portion and the protruding portion 44 of the heat sink 4 as the contactable portion can be extended in the direction orthogonal to the protruding portion 44. This suppresses an increase in the thickness of the heat transfer member 52 in the axial direction, thereby achieving miniaturization of the motor 1 in the axial direction.

The motor 1 of the present embodiment corresponds to an electronic device classified as a class II device having no protection ground. The class II equipment is one of the names of different products based on the insulation method, and is equipment that does not protect against electric shock, but is equipment that employs additional safety measures such as double insulation or reinforced insulation, instead of simple basic insulation.

The basic insulation means insulation for performing basic protection against electric shock, and an insulation distance (a creepage distance, a space distance) corresponding to an operating voltage is required.

The double insulation means insulation composed of both basic insulation and additional insulation. The additional insulation means independent insulation added to the basic insulation in order to protect against electric shock in the case of basic insulation failure.

The reinforced insulation means a single insulation that can protect against electric shock in mechanical and electrical aspects as well as double insulation.

For example, according to IEC (International Electro technical Commission: international electrotechnical Commission) 60335-2-40, which is one of the security standards for electronic devices, in the case of class II devices, the overvoltage is classified as: II. Degree of offset: 3. material group: in the case of IIIa, the distance A between the charging section and the contactable section is required to be 3mm or more and the creepage distance B is required to be 12.6mm or more as a standard value.

For example, as shown in fig. 6, when the electronic component 51 and the heat sink 4B are connected via the heat transfer member 52B having substantially the same area as the electronic component 51, in order to satisfy the above standard value between the wire portion 511 of the electronic component 51 and the heat sink 4B, it is necessary to increase the thickness of the heat transfer member 52B to ensure the insulation distance (the spatial distance a, the creepage distance B) between the electronic component 51 and the heat sink 4B. However, in this case, since the device in the thickness direction of the heat transfer member 52B is enlarged and the thickness of the heat transfer member 52B is increased, an increase in thermal resistance between the electronic component 51 and the heat sink 4B is unavoidable.

In contrast, according to the present embodiment, as shown in fig. 4 (a) and (B), the peripheral edge portion 523 of the heat transfer member 52 is located outside the outer peripheral edge L (the lead portion 511) of the electronic component 51, and therefore, the insulation distance (the space distance a, the surface distance B) from the lead portion 511 to the protruding portion 44 can be made longer than the configuration shown in fig. 6. Further, the surface distance B is also increased to the distance of the protrusion 44 by passing through the peripheral edge portion 523 of the heat transfer member 52, similarly to the space distance a. This can reduce the thermal resistance between the electronic component 51 and the heat sink 4 and improve the heat dissipation performance of the electronic component 51 while suppressing an increase in the thickness of the heat transfer member 52 and thereby achieving a reduction in the axial direction of the motor 1.

Further, according to the present embodiment, the peripheral edge portion 523 of the heat transfer member 52 has an eave portion 524, and the eave portion 524 is located on a path where the distance between the wire portion 511 and the annular protruding portion 43 becomes the shortest distance. This can increase the insulation distance (the space distance D) between the lead portion 511 and the annular protruding portion 43. Accordingly, it is possible to prevent discharge from occurring between the lead portion 511 and the annular protruding portion 43 due to a short circuit.

Further, according to the present embodiment, since the area of the opposing surface 441 is smaller than the area of the electronic component 51 as viewed in the axial direction, the insulation distance from the lead portion 511 to the protruding portion 44, particularly the creepage distance B, can be increased. Accordingly, the heat transfer member 52 can be made thinner in the axial direction, and therefore the motor 1 can be miniaturized in the axial direction.

Further, according to the present embodiment, a narrowed portion 442 is provided around the opposing surface 441 of the protruding portion 44. Thereby, the insulation distance from the wire portion 511 to the protrusion 44, that is, the space distance a and the creepage distance B can be increased as compared with the case where the narrowed portion 442 is not formed. Accordingly, the heat transfer member 52 can be made thinner in the axial direction, and therefore the motor 1 can be miniaturized in the axial direction.

< second embodiment >

Fig. 7 (a) and (B) are cross-sectional views of main parts of a motor 1A according to a second embodiment of the present invention.

Hereinafter, a structure different from that of the first embodiment will be mainly described, and the same reference numerals are given to the same structures as those of the first embodiment, and the description thereof will be omitted or simplified.

As shown in fig. 7 (a) and (B), the heat sink 4A of the present embodiment is different from the first embodiment in that the protrusion 44A has an inclined portion 440. Regarding the inclined portion 440, the area of the cross section of the protrusion portion 44A perpendicular to the axial direction becomes smaller as going from the disk portion 42A toward the electronic component 51. The inclined portions 440 are provided on the 4 side surfaces of the protruding portion 44A so that the protruding portion 44A has a truncated pyramid shape with the opposing surface 441 as the top. The shape of the projection 44A is not limited to the quadrangular frustum shape, and may be, for example, a frustum shape.

As shown in fig. 7 (a) and (B), the heat transfer member 52A has a peripheral portion 523 provided outside the heat transfer portion 521 and located outside the outer peripheral edge L of the electronic component 51 as viewed in the axial direction. The electronic component 51 is covered with the heat transfer member 52 as viewed from the protruding portion 44A. In the second embodiment, the inclined portion 440 increases the insulation distance from the lead portion 511 to the protruding portion 44A, particularly the creepage distance B. Accordingly, the heat transfer member 52A can be made thinner in the axial direction, and therefore, the motor 1B can be miniaturized in the axial direction.

< modification >

In the above-described embodiments, the number of the protrusions 44 of the heat sinks 4, 4A is 1, but the present invention is not limited to this, and a plurality of the protrusions may be provided in accordance with the electronic components and the like. For example, in the case where the number of electronic components having different heights is 2 or more, a plurality of projections corresponding to the respective heights may be provided, and in the case where 2 electronic components having the same height are located nearby, one projection may protrude toward 2 electronic components.

In the above-described embodiment, the single-axis motor that outputs a load (torque) by providing the load at one end of the shaft 6 of the motor 1 has been described as an example, but a double-axis motor that outputs a load (torque) by providing the load at both ends of the shaft 6 may be used.

In the above embodiment, the circuit board 5 has a disk shape along the inner peripheral surface 10a of the resin outer contour 10, but the present invention is not limited to this. As long as it can be supported by the mounting surface 9, it may be, for example, rectangular.

Further, in the above embodiment, the rotor body 30 is constituted by the three-divided structure of the outer peripheral side core 32, the insulating member 33, and the inner peripheral side core 34, but the present invention is not limited thereto, and may be constituted by a single core member.

The rotor 3 is not limited to the surface magnet type as in the embodiment, and may be an embedded magnet type in which a plurality of magnet embedded holes into which permanent magnets are embedded are formed in the rotor body 30 (rotor core).

Symbol description

1. 1A, 1B … motor

4. 4A, 4B … radiator (contactable part)

10 … resin outline

101 … open end

2 … stator

21 … stator core

3 … rotor

31 and … permanent magnet portion

32 … outer peripheral side core

33 … insulating member

34 … inner peripheral side iron core

41 … first bearing housing portion

42. 42A … disk portion

43. 43A … annular projection

44. 44A, 44B … projections

420. 420A … axial positioning part

430. 430A … annular projection

5 … circuit substrate

51 … electronic component (charging part)

52. 52A … heat transfer member

511 … wire portion

523 … peripheral edge portion

6 … rotating shaft

C … axle center

And the outer periphery of the L … electronic component.

Claims

1. An electric motor, comprising:

a cylindrical resin outer contour having an open end at one end side in an axial direction;

a stator including a coil and a stator core integrally formed with the resin outer contour;

a rotor disposed on an inner diameter side of the stator;

a heat sink covering the open end of the resin outer contour;

a circuit board disposed in an inner space covered by the resin outer contour and the heat sink, and having an electronic component; and

a heat transfer member disposed between the heat sink and the electronic component and having electrical insulation,

the heat sink has:

a disk portion that abuts the open end of the resin outer contour;

an annular protruding portion protruding from the circular plate portion toward the circuit board; and

a projection portion disposed on an inner diameter side of the annular projection portion, projecting from the disk portion toward the electronic component,

the heat transfer member has:

a heat transfer portion sandwiched between the electronic component and the protruding portion; and

and a peripheral edge portion provided outside the heat transfer portion and located outside an outer peripheral edge of the electronic component as viewed in the axial direction.

2. The motor according to claim 1, wherein,

the protruding portion has a protruding height from the circular plate portion that is larger than a protruding height of the annular protruding portion from the circular plate portion.

3. The motor according to claim 1 or 2, wherein,

the projection has an inclined portion or a narrowed portion in which the area of a cross section of the projection perpendicular to the axial direction becomes smaller as going from the disk portion toward the electronic component.

4. The motor according to any one of claims 1 to 3, wherein,

the projection has an opposing surface opposing the electronic component,

the area of the opposing surface is smaller than the area of the electronic component as viewed in the axial direction.

5. The motor according to any one of claims 1 to 4, wherein,

the electronic component includes a wire portion forming an outer periphery of the electronic component,

the peripheral edge portion of the heat transfer member includes an overhang portion located on a path where a distance between the lead portion and the annular projection portion becomes a shortest distance.