JP7255623B2 - Electric motor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric motor, and more particularly to an insulation structure for a circuit board incorporated in the electric motor.

2. Description of the Related Art Conventionally, an electric motor having a circuit board for controlling rotation of the electric motor is known.

For example, in Patent Document 1, a resin for molding a stator core and a metal bracket (lid member) that supports a bearing on the non-output side of the motor and is attached to the end of the resin on the non-output side of the motor is described. a radiator fin fixed to the end of the resin via the metal bracket and including projections that can be inserted into holes provided on the outer surface of the metal bracket; and a circuit board disposed inside the motor. A brushless motor having a structure in which the protrusions are brought into contact with electronic components on a circuit board via a thermally conductive resin is disclosed.

JP 2009-131127 A

In recent years, there has been a demand for miniaturization of this type of electric motor. On the other hand, due to the increase in the output of the electric motor, the size of the electronic components mounted on the circuit board arranged inside the electric motor has also increased. Insulating sheets that cover parts are also becoming larger. Therefore, there is a problem that the enlarged insulating sheet comes into contact with the inner peripheral surface of the resin outer shell.

SUMMARY OF THE INVENTION In view of the circumstances as described above, an object of the present invention is to provide an electric motor that can prevent an insulating sheet from coming into contact with a resin shell while achieving a reduction in the size of the electric motor.

In order to achieve the above object, an electric motor according to one aspect of the present invention includes a cylindrical resin shell having an open end at one end in the axial direction, and a coil and stator core integrally formed with the resin shell. a rotor arranged on the inner diameter side of the stator; a lid member covering the open end of the resin shell; and an internal space covered by the resin shell and the lid member. a circuit board having an electronic component; an insulating sheet having a peripheral edge portion positioned outside an outer peripheral edge of the electronic component when viewed in the axial direction; and an accommodating portion formed of a recessed recess that accommodates a part of the peripheral portion of the insulating sheet.

Since the electric motor is provided with the accommodating portion that accommodates a portion of the peripheral edge portion of the insulating sheet, the portion of the peripheral edge portion of the insulating sheet can be can be accommodated in the resin outer shell without contacting the inner peripheral surface of the

In the above electric motor, the peripheral portion of the insulating sheet is located on the shortest path between the portion protruding from the lid member toward the circuit board and the electronic component in the internal space covered with the resin shell and the lid member. good too. At this time, it is possible to increase the insulation distance (spatial distance) between the electronic component and the cover member while suppressing the increase in the thickness of the insulation sheet along the axial direction and miniaturizing the motor in the axial direction. , the insulation between the electronic component and the cover member can be ensured.

Also, the peripheral edge portion of the insulating sheet may be prevented from coming into contact with the inner peripheral surface of the resin outer shell. At this time, it is possible to prevent a short circuit from occurring between the electronic component and the lid member via the inner peripheral surface of the resin outer shell with which the insulating sheet contacts, and prevent dielectric breakdown from occurring due to a shortened creepage distance. can be prevented.

The circuit board may be formed in a disc shape having a central hole through which the rotating shaft passes, and the insulating sheet may be arranged so as to be separated from the central hole.

The circuit board further has a protruding piece portion having a terminal that protrudes from the peripheral edge portion of the circuit board toward the outer diameter side and is connected to an end portion of the coil, and the protruding portion is attached to the accommodating portion. may be accommodated.

The area of the cross section of the accommodating portion along the circumferential direction of the cylindrical resin shell may be smaller on the outer peripheral surface side of the resin shell than on the inner peripheral surface side of the resin shell.

The circuit board may have an insulating sheet positioning portion that indicates the position of the insulating sheet.

The insulating sheet may have heat conductivity, and the lid member may have a contact portion thermally contacting the electronic component via the insulating sheet.

The lid member may further have a projecting portion projecting toward the electronic component and having the contact portion on a surface facing the electronic component.

The heat transfer portion of the insulating sheet may be sandwiched between the electronic component and the protrusion.

ADVANTAGE OF THE INVENTION According to this invention, the electric motor which can prevent an insulating sheet contacting a resin outer shell can be provided, achieving a size reduction of an electric motor.

1 is a cross-sectional view of an electric motor according to a first embodiment of the present invention; FIG. It is a perspective view of the cover member in the said electric motor, Comprising: (A) is a front side perspective view, (B) is a back side perspective view. 1A is a side cross-sectional view of a main part of an electric motor according to a first embodiment of the present invention, and FIG. [FIG. 2] is a plan view of an electronic component viewed from the lid member side; FIG. 5 is a side cross-sectional view for explaining an insulation distance between the protrusion of the lid member and the electronic component; It is a general explanatory diagram of the insulation distance. FIG. 4 is a plan view of the inside of the resin outer shell as viewed from the lid member side; It is a perspective view inside a resin shell. It is sectional drawing of the accommodation part periphery. It is sectional drawing of the principal part of the electric motor which concerns on the modification of this invention, Comprising: (A) is the figure which showed the spatial distance, (B) is the figure which showed the creepage distance. It is a figure which the insulating sheet contacted the inner peripheral surface of the resin outer shell.

Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and may differ from reality. Therefore, specific components should be determined with reference to the following description.

Further, the embodiments shown below are examples of apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the shape, structure, arrangement, etc. of the component parts. It is not specific to the following. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

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

[Overall configuration of electric motor]
Electric motor 1 includes stator 2 (stator core 21 ), rotor 3 , resin shell 10 , first bearing 71 , second bearing 81 , lid member 4 , and circuit board 5 . ing.

The stator core 21 is integrally formed with the resin outer shell 10 .
The rotor 3 is fixed to the rotating shaft 6 and arranged on the inner diameter side of the stator core 21 .
The resin shell 10 has a cylindrical shape having an open end 101 at one end in a direction parallel to the axis C of the rotating shaft 6 (hereinafter also referred to as an axial direction).
The lid member 4 is arranged to cover the open end 101 of the resin shell 10 .
The circuit board 5 is arranged in an internal space covered with the resin shell 10 and the lid member 4 .

In the following, 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 radially inside a cylindrical stator 2 that generates a rotating magnetic field will be described. A motor 1 will be described. The electric motor 1 is of course not limited to this, and may be, for example, an outer rotor type brushless DC motor, an AC motor, or another electric motor.

Further, in the following description, the axis C of the rotating shaft 6 is also the central axis of the electric motor 1 , that is, the rotation axis of the rotor 3 . The radial direction is a direction passing through the axis C and orthogonal to the axial direction. The inner diameter side is the inner side in the radial direction, and the outer diameter side is the outer side in the radial direction. Furthermore, the circumferential direction is the direction of rotation about the axis C. As shown in FIG.

(rotor)
The rotor 3 has an annular permanent magnet portion 31 and a rotor main body 30 . The rotor main body 30 has an outer peripheral surface and an inner peripheral surface. A permanent magnet portion 31 is fixed to the outer peripheral surface of the rotor main body 30 . A rotating shaft 6 is fixed to the inner peripheral surface of the rotor main body 30 . As a result, the rotating shaft 6 rotates integrally with the rotor main body 30 .

The rotor 3 is of 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 annularly formed of a plurality of (e.g., 8 or 10) permanent magnets so that N poles and S poles appear alternately at equal intervals in the circumferential direction. The permanent magnet portion 31 is typically made of a sintered metal such as an Nd--Fe--B alloy. A plastic magnet may also be used.

As shown in FIG. 1 , the rotor body 30 has an outer core 32 , an insulating member 33 and an inner core 34 .

The outer core 32 is annular and forms the outer peripheral surface of the rotor main 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 peripheral iron core 34 is formed in an annular shape and forms the inner peripheral surface of the rotor main body 30 .
The inner peripheral core 34 is a laminate of plates made of a soft magnetic material such as a plurality of electromagnetic steel plates. The rotating shaft 6 is fixed to the center of the inner peripheral iron core 34 by press fitting or caulking.

The insulating member 33 electrically insulates between the outer core 32 and the inner core 34 . As a result, the difference between the static capacitance on the stator side and the static capacitance on the rotor side of the electric motor 1 can be reduced, and electrolytic corrosion of the bearings 71 and 81 can be suppressed. The insulating member 33 is made of dielectric resin 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 an annular molded body, or may be a resin material filled between the outer core 32 and the inner 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 radially from the yoke, and a plurality of windings (coils) 22 wound around the teeth. I have. The stator core 21 is, for example, a laminate of plates made of a soft magnetic material such as a plurality of electromagnetic steel plates. The plurality of coils 22 includes U-phase, V-phase and W-phase coils. These coils are interconnected, for example, via an electrical neutral point (N point). The outer peripheral surface of the stator 2 (stator core 21) is covered with a resin shell 10 (see FIG. 1). The stator 2 is arranged such that the permanent magnet portion 31 of the rotor 3 faces the stator core 21 of the stator 2 in the radial direction via an air gap (magnetic gap).

(Resin shell)
The resin shell 10 is made of an insulating resin material. As shown in FIG. 7, the resin outer shell 10 is formed in a hollow cylindrical shape having an open end 101 at one axial end (in this embodiment, the side opposite to the output end 61 of the rotary shaft 6). Here, the counter-output end portion 61 is the end portion of the rotary shaft 6 opposite to the output end portion 62 . The output end portion 62 is the end portion of the electric motor 1 on the load side (the side connected to the load).
As described above, the resin shell 10 is integrally molded with the stator 2 . The resin material forming the resin shell 10 is not particularly limited, and for example, BMC (Bulk Molding Compound: unsaturated polyester resin) resin is used.

Further, the resin shell 10 has a mounting surface 9 . The mounting surface 9 is formed on the inner peripheral surface 10a side of the resin outer shell 10, is a plane perpendicular to the axial direction, and is provided on the counter-output end portion 61 side of the rotating shaft 6 relative to the rotor 3 in the axial direction. . The mounting surface 9 supports the circuit board 5 which will be described later. In the present embodiment, the mounting surface 9 is the surface of the counter-output end portion 61 side of the step provided so as to protrude from the inner peripheral surface 10a of the resin outer shell 10 toward the inner diameter side. The mounting surface 9 may be formed continuously in the circumferential direction of the inner peripheral surface 10a of the resin outer shell 10, or may be formed at a plurality of locations at intervals in the circumferential direction.

The resin outer shell 10 further has a second bearing accommodating portion 82 that accommodates a second bearing 81, which will be described later. The general shape of the second bearing accommodating portion 82 is a cylindrical shape centered on the axis C and one end side of which is closed. The second bearing accommodating portion 82 is provided on the bottom portion 102 of the resin outer shell 10 on the side opposite to the open end portion 101 .

(circuit board)
FIG. 6 is a plan view of the inside of the resin outer shell 10 viewed from the lid member 4 side (open end portion 101 side). FIG. 7 is a perspective view of the inside of the resin shell 10. FIG.
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 side opposite to the output end 61 of the rotary shaft 6) and generating heat when energized. The circuit board 5 has a center hole 50a through which the rotating shaft 6 passes, and is formed in a substantially disc shape. A peripheral portion of the circuit board 5 is supported by the mounting surface 9 and fixed by, for example, adhesion, adhesion, screw fastening, soldering, or the like.

As shown in FIG. 7, the mounting surface 9 includes an arcuate first region 9a formed along the inner surface of the resin outer shell 10, and an arc-shaped first region 9a extending from the first region 9a toward the outer peripheral surface 10b of the resin outer shell 10 (outer surface 10b). and a plurality of (five in this example) second regions 9b extending toward the radial side). The first region 9a supports the outer peripheral edge of the circuit board 5, and the second region 9b supports projecting pieces 54 of the circuit board 5, which will be described later. The second region 9b is formed in a recess 104, which will be described later, formed in the resin outer shell 10. As shown in FIG.
Further, the mounting surface 9 is provided with a plurality of (two in this example) positioning pins 9c penetrating the circuit board 5 .

The circuit board 5 has a plurality of (five in this example) projecting pieces 54 . Each protruding piece 54 extends from the peripheral edge of the circuit board 5 toward the outer peripheral surface 10b side (outer diameter side) of the resin shell 10, and has a terminal 56 connected to the end 221 of the coil 22. . Each protruding piece 54 is arranged in the second area 9 b of the mounting surface 9 . The terminal 56 of each projection 54 is connected to the end 221 of the coil 22 projecting from the mounting surface 9 (see FIGS. 6 and 7). The terminal 56 is electrically connected to the electronic component 51 and supplies the drive signal output from the electronic component 51 to each coil 22 . The circuit board 5 is positioned on the mounting surface 9 by a plurality of positioning pins 9c, and is fixed on the mounting surface 9 by soldering the terminals 56 and the ends 221 of the coils.

In this embodiment, the end portion 221 of the coil 22 is configured to pass through the projecting piece portion 54, but this is not the only option. For example, the coil 22 and the circuit board 5 may be electrically connected by arranging the terminal 56 on the mounting surface 9 side of the protrusion 54 and bringing the end 221 of the coil 22 into contact.
Further, as shown in FIGS. 6 and 7, the inner peripheral surface 10a of the resin outer shell 10 may be partially provided with a recess 104 for positioning for accommodating the projecting piece 54, whereby the circuit board 5 is also fixed. It can be fixed to the mounting surface 9 while being positioned in the circumferential direction.
Further, in the present embodiment, the circuit board 5 is formed in a disk shape having a central hole 50a through which the rotating shaft 6 passes, so that the mounting area on the circuit board 5 can be increased. In addition, the shape of the circuit board 5 is not limited to a disc shape, and may be, for example, a square shape.

As shown in FIGS. 3A and 3B, the electronic component 51 has a component body 510 and lead portions 511 extending from two opposite sides of the component body 510 . Note that the lead portions 511 are not limited to extending from two side surfaces of the component body 51, and may extend from only one side surface or from four side surfaces. The component main body 510 is a synthetic resin package part containing a semiconductor element. The lead part 511 is composed of a plurality of metal external terminals electrically connected to the wiring board 50 and forms at least part of the outer peripheral edge of the electronic component 51 . The electronic components 51 that generate heat when energized are mainly semiconductor package components such as power supply ICs and motor drive current control ICs, but may be passive components such as capacitors.

In addition to the electronic component 51, the wiring board 50 is mounted with other components such as a connector component to be connected to a power cable, but illustration of these components is omitted. The power cable is connected to a power source (not shown) through a cable insertion portion 105 (see FIGS. 6 and 7) formed in the vicinity of the open end portion 101 of the resin shell 10 over a predetermined angular range in the circumferential direction.

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

The outer ring 711 of the first bearing 71 is fixed to the cover member 4 (the first bearing housing portion 41), and the inner ring 712 of the first bearing 71 is fixed to the counter-output end portion 61 side of the rotary shaft 6. . The outer ring 813 of the second bearing 81 is fixed to the resin outer shell 10 (second bearing accommodating portion 82 ), and the inner ring 812 of the second bearing 81 is fixed to the output end portion 62 of the rotary shaft 6 . Thereby, the rotating shaft 6 is rotatably supported around the axis C with respect to the cover member 4 and the resin shell 10 by the first bearing 71 and the second bearing 81 .

(Lid member)
The lid member 4 has a first bearing accommodating portion 41 , a disk portion 42 , an annular projecting portion 43 , and a projecting portion 44 . The lid member 4 is attached and fixed to the open end 101 of the resin shell 10 . The lid member 4 is made of a metal material having excellent thermal conductivity, such as aluminum. The lid member 4 is integrally formed with a disk portion 42, an annular projecting portion 43, and a projecting portion 44, respectively. The lid member 4 is molded by die casting (casting), for example.

The lid member 4 functions as a lid (bracket) that closes the opening of the resin outer shell 10 by covering the opening end 101 of the resin outer shell 10, and as a bearing housing part (bearing house) that supports the first bearing 71. and as a heat radiating member that radiates heat generated by the electronic components 51 inside the motor to the outside of the motor. The lid member 4 is fixed to the open end portion 101 of the resin shell 10 using a plurality of unillustrated screw members.

2A is a perspective view of the inner surface side (lower surface side in FIG. 1) of the lid member 4, and FIG. 2B is a perspective view of the outer surface side of the lid member 4 (upper surface side in FIG. 1). .

The disk portion 42 is an annular plate portion having a center hole 40 centered on the axis C. As shown in FIG. In this embodiment, the outer diameter of the disc portion 42 is the same or substantially the same size as the outer diameter of the open end portion 101 of the resin shell 10 . As shown in FIGS. 2A and 2B, the disk portion 42 has an upper surface 423 and a rear surface 424 on the opposite side. As will be described later, the upper surface portion 423 of the disk portion 42 is formed with the first bearing accommodating portion 41 . A rear surface 424 of the disk portion 42 is provided with the axial positioning portion 420 , the annular projection portion 43 and the projection portion 44 .

The annular protruding portion 43 is formed to protrude from the rear surface 424 side of the disk portion 42 toward the circuit board 5 side. Further, the annular projecting portion 43 has a radial positioning portion 430 that contacts the inner peripheral surface 10 a of the resin outer shell 10 .

The projecting portion 44 is arranged on the inner diameter side of the annular projecting portion 43, projects from the back surface 424 side of the disk portion 42 toward the circuit board 5 side, and thermally contacts the circuit board 5 (the electronic component 51 in this embodiment). It has a contact portion 441 that contacts the . In the present embodiment, as shown in FIG. 1, when the cover member 4 is attached to the resin outer shell 10, the protrusion 44 is formed in a region between the first bearing accommodating portion 41 and the annular protrusion 43 in the radial direction. , facing the electronic component 51 .
The details of each unit will be described below.

(First bearing accommodating portion)
The first bearing housing portion 41 houses the first bearing 71 . The first bearing accommodating portion 41 has a substantially cylindrical shape centered on the axis C and accommodates the first bearing 71 . The first bearing accommodating portion 41 is formed on the upper surface 423 side of the inner peripheral edge portion 401 of the center hole 40 of the disc portion 42 .

(Disc part)
The disk portion 42 has an axial positioning portion 420 . As shown in FIG. 2A, the axial positioning portion 420 is formed on the rear surface 424 side of the outer peripheral edge portion 422 of the disc portion 42 . In the present embodiment, the outer peripheral edge portion 422 is a region of the disk portion 42 that is closer to the outer diameter than the annular projecting portion 43 .

The axial thickness of the disk portion 42 in the area on the inner diameter side of the outer peripheral edge portion 422 may be thinner than the axial thickness of the outer peripheral edge portion 422 . When the thickness of the disk portion 42 in the area 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. 425 may be provided. A plurality of rib portions 425 are radially formed from the first bearing accommodating portion 41 toward the annular projecting portion 43 . By providing the plurality of rib portions 425, the strength of the lid member 4 can be ensured.

The axial positioning portion 420 is formed on the rear surface 424 side of the outer peripheral edge portion 422 and contacts the open end portion 101 of the resin outer shell 10 . As shown in FIG. 1, the axial positioning portion 420 faces the open end portion 101 in the direction of the axis C. As shown in FIG. As shown in FIG. 2A, the axial positioning portion 420 is formed by a plane perpendicular to the axis C over the entire rear surface 424 side of the outer peripheral edge portion 422, but this is not the only option. For example, the axial positioning portion 420 of the lid member 4 may have an annular projection projecting toward the open end 101, and the open end 101 of the resin shell 10 has an annular projection corresponding to the projection. grooves. A cross section of the protruding portion viewed from the radial direction may be trapezoidal or curved.

As shown in FIGS. 2A and 2B, holes 421 through which screws are inserted are formed at a plurality of locations on an outer peripheral edge portion 422 of the disc portion 42 . In this embodiment, three holes 421 are provided at equal angular intervals on the outer peripheral edge 422 . Note that the number and positions of the holes 421 provided in the outer peripheral edge portion 422 can be changed as appropriate, and the outer peripheral edge portion 422 need not be provided with the hole portions 421 . In this embodiment, a screw receiving portion 103 is formed in the open end portion 101 of the resin outer shell 10 at a position facing the hole portion 421 . The lid member 4 is fixed to the open end portion 101 of the resin shell 10 with a plurality of screws inserted through the holes 421 . At this time, the lid member 4 is positioned in the circumferential direction with respect to the open end portion 101 of the resin outer shell 10 .

The disc portion 42 further has a notch portion 426 formed over a predetermined angular range in a portion of the outer peripheral edge portion 422 thereof. The notch portion 426 is provided at a position corresponding to the above-described cable insertion portion formed over the vicinity of the open end portion 101 of the resin outer shell 10 . Accordingly, the cutout portion 426 can be used as a mark for positioning the resin shell 10 in the circumferential direction when the lid member 4 is assembled to the open end portion 101 of the resin shell 10 .

(Annular protrusion)
As mentioned above, the annular projection 43 has a radial positioning portion 430 . In this embodiment, the radial positioning portion 430 is formed on the outer peripheral surface of the annular projecting portion 43 that contacts the inner peripheral surface 10 a of the open end portion 101 of the resin outer shell 10 . That is, as shown in FIGS. 1 and 2A, the radial positioning portion 430 has a cylindrical surface that fits into the inner peripheral surface 10 a of the resin outer shell 10 .

As shown in FIG. 2A, the annular projecting portion 43 is formed in an annular shape around the axis C on the rear surface 424 of the disc portion 42 . As shown in FIG. 1, the cross section parallel to the axis C of the annular protrusion 43 is generally rectangular. In addition, as shown in FIG. 2A, the annular projecting portion 43 is continuously formed in the circumferential direction without a break, but the present invention is not limited to this, and a portion of the projecting portion 43 may have a break.

(protrusion)
As described above, the projecting portion 44 is arranged on the inner diameter side of the annular projecting portion 43 and projects from the back surface 424 of the disk portion 42 toward the circuit board 5 side in the axial direction.

As shown in FIG. 2A, in the present embodiment, the protrusion 44 is a rectangular parallelepiped block that protrudes toward the electronic component 51 mounted on the circuit board 5 . Furthermore, the protrusion 44 has a contact portion 441 facing the electronic component 51 . In addition, the shape of the protrusion 44 is not limited to a rectangular parallelepiped shape, and may be, for example, a cylindrical shape.

As shown in FIG. 1, it is preferable that the projection 44 has a projection height in the axial direction greater than the projection height of the annular projection 43 . The protrusion height referred to here is the height of protrusion toward the circuit board in the axial direction with respect to the back surface 424 of the disc portion 42 . In the present embodiment, the contact portion 441 of the protrusion 44 is positioned closer to the circuit board 5 than the tip portion of the annular protrusion 43 in the axial direction. The protrusion height of the protrusion 44 is such that the contact portion 441 of the protrusion 44 touches the upper surface of the electronic component 51 when the axial positioning portion 420 of the disc portion 42 contacts the open end portion 101 of the resin outer shell 10 . It is set to form a gap with a size within a predetermined range.

The shape of the contact portion 441 viewed from the electronic component 51 side may be formed in accordance with the shape of the electronic component 51, and is, for example, a rectangular plane (see FIG. 2A). The area of the contact portion 441 is smaller than the area of the electronic component 51 when viewed from the protrusion 44 . The contact portion 441 may be formed flat by a lathe or the like after the lid member 4 is formed by die casting or the like. In this case, since the protruding height of the protrusion 44 in the axial direction is formed to be greater than the protruding height of the annular protrusion 43, the annular protrusion 43 does not hinder machining of the contact portion 441 using a lathe or the like. can be prevented. As a result, the axial heights of the axial positioning portion 420 and the contact portion 441 of the lid member 4 can be set to appropriate dimensions. Variations in processing and assembly in the axial direction of the member 4 can be suppressed.

In this embodiment, the contact portion 441 is formed at the tip of the protrusion 44, but this is not the only option. For example, depending on the height of the electronic component 51, the distance between the disk portion 42 and the circuit board 5, etc., the electronic component 51 may be brought into direct contact with the disk portion 42 without providing the projection portion 44. . In this case, the contact portion 441 is the portion of the back surface portion 424 of the disk portion 42 that is in thermal contact with the electronic component 51 .

FIG. 3A is an enlarged view showing a connecting portion between the protrusion 44 and the electronic component 51 in FIG. FIG. 3B is a schematic plan view of the electronic component 51 viewed from the protrusion 44. FIG.
As shown in FIG. 3A, an insulating sheet 52 and an adhesive member 53 are arranged in order from the electronic component 51 side between the electronic component 51 and the protrusion 44 .

The insulating sheet 52 preferably has good thermal conductivity and high insulating properties, and for example, a heat dissipation sheet made of silicone resin is used. Similarly, the adhesive member 53 preferably has good thermal conductivity and high insulating properties, and for example, a silicon resin adhesive is used.
In this embodiment, an adhesive member 53 is provided between the protrusion 44 and the insulating sheet 52 , and the contact portion 441 of the protrusion 44 is connected to the electronic component 51 via the insulating sheet 52 and the adhesive member 53 . come into direct contact. Note that the protrusions 44 are not limited to this, and may be in direct contact with the insulating sheet 52 .

The adhesive member 53 not only bonds the insulating sheet 52 and the protrusion 44 together, but also absorbs variations in axial position between the protrusion 44 and the electronic component 51 due to deformation of the adhesive member 53 . Further, the adhesive member 53 relieves the pressing force from the projecting portion 44 to the electronic component 51 by deformation of the adhesive member 53 when the cover member 4 is fitted to the resin outer shell 10 . As a result, a stable thermal connection between the protrusion 44 and the electronic component 51 can be ensured, and the heat transfer property can be improved. can be prevented.

The distance between the contact portion 441 and the electronic component 51 is set to be equal to or less than the sum of the thickness of the insulating sheet 52 and the thickness of the adhesive member 53 . Thereby, the contact portion 441 can be stably brought into contact with the upper surface of the electronic component 51 via the insulating sheet 52 and the adhesive member 53 .

Further, in this embodiment, as shown in FIG. 3A, a constricted portion 442 is provided around the contact portion 441 of the protrusion 44 . The constricted portion 442 is formed by a stepped portion 443 formed around the protrusion 44 on the contact portion 441 side. The constricted portion 442 allows a portion of the adhesive member 53 protruding outside the protruding portion 44 to escape to the outer peripheral surface side of the constricted portion 442 when the protruding portion 44 is pressed against the adhesive member 53 . As a result, the protrusion 44 and the insulating sheet 52 are stably brought into contact with each other, so that the adhesive strength and heat transfer between the protrusion 44 and the heat transfer member 52 can be improved.

(Insulating sheet)
Next, details of the insulating sheet 52 will be described. As shown in FIG. 3(B), the insulating sheet 52 is formed in a substantially rectangular shape large enough to cover the entire electronic component 51 when viewed from the axial direction. The insulating sheet 52 has three regions, a heat transfer portion 521 , an intermediate portion 522 and a peripheral edge portion 523 , when viewed two-dimensionally.

The heat transfer portion 521 is located substantially in the center of the insulating sheet 52 and is a region sandwiched between the electronic component 51 and the contact portion 441 of the protrusion 44 . Heat transfer portion 521 forms a heat transfer path between protrusion 44 and electronic component 51 . The intermediate portion 522 is a generally rectangular and annular region located between the heat transfer portion 521 and the peripheral edge portion 523 .

The peripheral portion 523 is formed outside the heat transfer portion 521 . That is, it is a rectangular ring-shaped area positioned outside the outer peripheral edge L of the electronic component 51 when viewed from the protrusion 44 . The peripheral edge portion 523 may be in contact with the lead portions 511 of the electronic component 51 or may be out of contact therewith. Further, the outer peripheral edge L of the electronic component 51 is a boundary portion of the area occupied by the entire electronic component 51 when viewed in the axial direction. It is a virtual rectangular frame surrounding a component body 510 and lead portions 511 that form the outer shape.

A peripheral edge portion 523 of the insulating sheet 52 includes a shielding portion 524 . The shielding portion 524 is part of the peripheral edge portion 523, and as shown in FIG. To position. The formation range of the shielding portion 524 is not particularly limited, and it is only necessary to increase the spatial distance between the lead portion 511 extending from the side surface of the component body 510 located on the annular protrusion 43 side and the annular protrusion 43 .

(Accommodation part)
The resin outer shell 10 further has a housing portion 11 . As shown in FIGS. 6 and 7 , the accommodating portion 11 is formed as a recess that is recessed from the inner peripheral surface 10 a side of the resin outer shell 10 toward the outer peripheral surface 10 b side (outer diameter side). The accommodation portion 11 accommodates a portion of the peripheral portion 523 of the insulating sheet 52 . The inner wall surface 110 of the accommodating portion 11 is separated from the peripheral edge portion 523 of the insulating sheet 52 . In the present embodiment, the accommodation portion 11 accommodates a corner portion of the peripheral edge portion 523 of the insulating sheet 52 covering the electronic component 51 that is closest to the inner peripheral surface 10 a of the resin outer shell 10 . The shape of the opening of the housing portion 11 when viewed from the lid member 4 is a substantially trapezoidal shape in which the side on the side of the outer peripheral surface 10b along the circumferential direction of the resin shell 10 is shorter than the side on the side of the inner peripheral surface 10a. It has a shape in which the opening of the concave portion 104 that accommodates one of the protruding pieces 54 is expanded to one side in the circumferential direction. The area of the cross section of the accommodating portion 11 along the circumferential direction of the resin shell 10 is smaller on the side of the outer peripheral surface 10b of the resin shell 10 than on the side of the inner peripheral surface 10a of the resin shell 10 .

FIG. 8 is a vertical cross-sectional view of the housing portion 11 and its surroundings. As shown in FIG. 8 , the accommodating portion 11 is one of the inner wall surfaces 110 , which is tapered from the upper opening side (the opening end portion 101 of the resin outer shell 10 ) toward the mounting surface 9 side below. It has a face 111 . The tapered surface 111 is inclined with respect to the inner peripheral surface 10 a of the resin outer shell 10 with which the outer peripheral surface (radial positioning portion 430 ) of the annular projecting portion 43 of the lid member 4 abuts. avoid interference with The formation position and formation angle of the tapered surface 111 are not particularly limited, and can be arbitrarily set according to the position of the insulating sheet 52, the shape of the peripheral portion, and the like.

Note that the accommodating portion 11 is not limited to the case where the inner wall surface 110 is formed with the tapered surface 111 , and the inner wall surface 110 may not interfere (contact) with the insulating sheet 52 . That is, it is sufficient that the inner wall surface 110 of the accommodating portion 11 is separated from the peripheral portion 523 of the insulating sheet 52 . For example, the inner wall surface 110 of the housing portion 11 may be formed only by a wall surface along the axial direction. In this embodiment, a predetermined gap is formed between the inner wall surface 110 of the housing portion 11 and the insulating sheet 52 so as to ensure an insulating distance, which will be described later.

Also, the insulating sheet 52 is arranged with a predetermined gap E formed between it and the rotating shaft 6 . The predetermined gap E may be any distance that can ensure an insulation distance (particularly a spatial distance), which will be described later.

In this embodiment, the accommodating portion 11 is formed as part of the positioning recess 104 that accommodates the projecting portion 54 of the circuit board 5 . As a result, it is not necessary to separately provide a recessed accommodating portion on the inner peripheral surface 10 a of the resin outer shell 10 . Note that the accommodation portion 11 is not limited to being formed as part of the recess 104 , and may be formed independently of the recess 104 . Further, as shown in FIG. 6, a plurality of recesses 104 that can also serve as the housing portion 11 may be provided in advance. Accordingly, any recess 104 can be used as the housing portion 11 according to the mounting position of the electronic component 51, the shape and size of the insulating sheet 52, and the like.

The circuit board 5 has an insulating sheet positioning portion 55 that indicates the position of the insulating sheet 52 . As a result, the insulating sheet 52 can be easily arranged at a position where it does not come into contact with the resin outer shell 10 and the rotating shaft 6, so that the workability of attaching the insulating sheet 52 is improved. The shape of the insulating sheet positioning portion 55 is not particularly limited, and in this embodiment, as shown in FIG. formed by This makes it possible to easily confirm the positions where the corners of the insulating sheet 52 are arranged. Therefore, by aligning the corner of the insulating sheet 52 with the L-shaped line of the insulating sheet positioning portion 55 , the other corner of the insulating sheet 52 can be positioned at the predetermined position of the housing portion 11 formed in the resin shell 10 . can be easily positioned. When viewed from the lid member 4, the insulating sheet positioning portion 55 and the corner portion of the insulating sheet 52 may or may not match. The insulating sheet positioning portion 55 is not limited to being formed by an L-shaped line, and may be formed by an I-shaped line, for example. In this case, the position where one side of the peripheral portion 523 of the insulating sheet 52 is arranged can be easily confirmed.

[Function of insulating sheet]
As described above, the insulating sheet 52 of the present embodiment includes the heat transfer portion 521 sandwiched between the electronic component 51 and the contact portion 441 of the protrusion 44, and the protrusion 44 provided outside the heat transfer portion 521. and a peripheral edge portion 523 located outside the outer peripheral edge L of the electronic component 51 . Therefore, the insulating sheet 52 covers the electronic component 51 when viewed from the protrusion 44 . By covering the electronic component 51 with the insulating sheet 52 when viewed from the projection 44 , a sufficient insulation distance (space distance, creepage distance) between the lead portion 511 of the electronic component 51 and the projection 44 can be ensured.

Spatial distance is the shortest distance through space between two conductive members (live part and accessible part). Also, the creepage distance is the shortest distance along the surface of the insulator between two conductive members (the live portion and the accessible portion). A live part refers to a conductive part to which a voltage is applied inside the electric motor. In this embodiment, an electronic component 51 having metal lead portions 511 is provided as a charging portion. Also, the tangible portion refers to a part that is exposed to the outside of the electric motor and can be touched by a user. In this embodiment, a metallic lid member 4 is provided as the tangible portion. Insulation distance is a generic term that refers to both clearance and creepage distance.

Here, the spatial distance A and the creepage distance B will be described with reference to FIG.
The spatial distance A is the shortest distance through the space between the lead portion 511 , which is the metal portion of the electronic component 51 , and the projection portion 44 . In the present embodiment, the spatial distance A is the sum of the distance of the straight line from the lead portion 511 to the peripheral edge portion 523 of the insulating sheet 52 and the distance of the straight line from the peripheral edge portion 523 of the insulating sheet 52 to the protrusion 44 . be. As shown in FIG. 4, the creepage distance B is the shortest distance between the lead portion 511, which is the metal portion of the electronic component 51, and the protrusion 44 measured along the surface of the insulating sheet 52. FIG. In this embodiment, the creepage distance B is the distance from the lead portion 511 to the protrusion 44 along each surface of the component body 510 of the electronic component 51, the insulating sheet 52, and the adhesive member 53 in this order.

According to the electric motor 1 of the present embodiment, since the peripheral edge portion 523 of the insulating sheet 52 is positioned outside the peripheral edge L of the electronic component 51, the lead portion 511 of the electronic component 51 which is the charging portion and the contactable portion The insulation distance (spatial distance A, creepage distance B) between the cover member 4 and the projection 44 can be extended in a direction orthogonal to the projection 44 . As a result, the thickness of the insulating sheet 52 in the axial direction can be reduced, and the miniaturization of the electric motor 1 in the axial direction can be achieved.

The electric motor 1 of this embodiment corresponds to an electronic device classified as a class II device that does not have a protective earth wire. Class II equipment is one of the classification names of products according to the difference in insulation method, and equipment that has additional safety measures such as double insulation or reinforced insulation, not just basic insulation, to protect against electric shock. Equipment that is not grounded.
Basic insulation is insulation that provides basic protection against electric shock, and requires an insulation distance (creeping distance, clearance distance) according to the operating voltage.
Double insulation is insulation that consists of both basic insulation and supplementary insulation. Supplementary insulation is independent insulation added to the basic insulation to provide protection against electric shock in the event of a breakdown of the basic insulation.
Reinforced insulation is single insulation that is mechanically and electrically equivalent in protection against electric shock to double insulation.
For example, according to IEC (International Electro technical Commission) 60335-2-40, which is one of the safety standards for electronic equipment, for class II equipment, overvoltage category: II, pollution degree: 3, material group: IIIa. As standard values, it is required to secure a spatial distance A of 3 mm or more and a creeping distance B of 12.6 mm or more between live parts and accessible parts.

For example, as shown in FIG. 5, when the electronic component 51 is connected to the lid member 4B through an insulating sheet 52B having approximately the same area as the electronic component 51, the lead portions 511 of the electronic component 51 and the lid member 4B are separated from each other. In order to satisfy the standard values, it was necessary to increase the thickness of the heat transfer member 52B to secure the insulation distance (space distance A, creepage distance B) between the electronic component 51 and the lid member 4B. However, in this case, an increase in thermal resistance between the electronic component 51 and the lid member 4B was inevitable due to the increase in the size of the device in the thickness direction of the insulating sheet 52B and the increase in the thickness of the heat transfer member 52B.

On the other hand, according to this embodiment, as shown in FIG. The insulation distance (space distance A, creepage distance B) from 511 to projection 44 can be made longer than the structure shown in FIG. Moreover, since the creepage distance B also passes through the peripheral edge portion 523 of the insulating sheet 52 in the same manner as the spatial distance A, the distance to the projection portion 44 can be increased. As a result, it is possible to reduce the size of the electric motor 1 in the axial direction by suppressing an increase in the thickness of the insulating sheet 52, and to reduce the thermal resistance between the electronic component 51 and the lid member 4, thereby reducing the size of the electronic component 51. It is possible to improve heat dissipation.

Furthermore, according to this embodiment, as shown in FIG. and the annular projection 43 (spatial distance D). Therefore, it is possible to prevent discharge from occurring due to a short circuit between the lead portion 511 and the annular projecting portion 43 .

Further, according to this embodiment, since the area of the contact portion 441 is smaller than the area of the electronic component 51 when viewed in the axial direction, the insulation distance from the lead portion 511 to the projection portion 44, particularly the creepage distance B, is increased. be able to. As a result, the thickness of the insulating sheet 52 can be reduced in the axial direction, so that the size of the electric motor 1 can be reduced in the axial direction.

In addition, as described above, the insulating sheet 52 is arranged so that a predetermined gap E is formed between the rotating shaft 6 and the insulating sheet 52 . The predetermined gap E is the spatial distance described above. For example, as a standard value in the case described above, it is necessary to secure a spatial distance of 3 mm or more. By providing the predetermined gap E, the insulation distance between the rotating shaft 6 and the circuit board 5 is ensured.

[Operation of housing part]
As described above, the insulating sheet 52 is located outside the heat transfer portion 521 sandwiched between the electronic component 51 and the lid member 4 and outside the outer peripheral edge L of the electronic component 51 when viewed in the axial direction (in other words, insulating and a peripheral edge portion 523 provided outside the heat transfer portion 521 in the sheet 52 . A portion of the peripheral portion 523 of the insulating sheet 52 is accommodated in the accommodation portion 11 . In addition, the peripheral edge portion 523 of the insulating sheet 52 and the inner wall surface of the accommodating portion 11 of the resin outer shell 10 are separated from each other so that a predetermined gap is formed. As a result, as shown in FIG. 8, a part of the peripheral edge portion 523 of the insulating sheet 52 can be accommodated in the resin outer shell 10 without contacting the inner peripheral surface 10a of the resin outer shell 10 and the inner wall surface of the accommodating portion 11. can be done. Therefore, even when the insulating sheet 52 having a large area is used, the peripheral edge portion 523 of the insulating sheet 52 can be prevented from coming into contact with the resin shell 10, and the creepage distance B between the electronic component 51 and the lid member 4 can be secured. can be done. In addition, since the accommodating portion 11 is formed with a depression extending from the inner peripheral surface 10a side of the resin outer shell 10 toward the outer diameter side (the outer peripheral surface 10b side), the resin outer shell 10 is prevented from increasing in size in its radial direction. can do.

FIG. 10 shows the internal structure of the electric motor 1C provided with the resin shell 10C without the accommodating portion 11. As shown in FIG. If the accommodating portion 11 is not formed, a part of the peripheral edge portion 523 of the insulating sheet 52 contacts the inner peripheral surface of the resin outer shell 10C, and furthermore, when the insulating sheet 52 is arranged on the electronic component 51, the As shown in 10, the peripheral edge portion 523 of the insulating sheet 52 is deformed so as to be turned up. Therefore, in this state, compared with the case where the peripheral edge portion 523 of the insulating sheet 52 does not contact the inner peripheral surface of the resin outer shell 10C, the short circuit represented by the creepage distance B1 between the electronic component 51 and the annular projecting portion 43 is reduced. As a result, a sufficient creepage distance cannot be secured between the electronic component 51 and the lid member 4, and dielectric breakdown may occur between the electronic component and the lid member via the inner surface of the resin outer shell. There is On the other hand, if the inner diameter of the resin outer shell 10C is increased so that the insulating sheet 52 and the inner peripheral surface of the resin outer shell 10C do not come into contact with each other, the electric motor 1C is inevitably enlarged in the radial direction.

In contrast, in the present embodiment, as described above, the accommodating portion 11 is provided on the inner peripheral surface 10a of the resin outer shell 10 so as to be recessed from the inner peripheral surface 10a side of the resin outer shell 10 toward the outer diameter side. A portion of the peripheral portion 523 of the insulating sheet 52 is accommodated in the accommodation portion 11 . As a result, contact between the insulating sheet 52 and the resin outer shell 10 caused by the insulating sheet 52 riding on the inner peripheral surface 10a of the resin outer shell 10 can be avoided, and an increase in the radial size of the resin outer shell 10 can be suppressed. Therefore, by using the insulating sheet 52 having a large area, the creepage distance between the electronic component 51 and the protrusion 44 is increased, and the insulating sheet 52 and the resin shell 10 are separated between the electronic component 51 and the annular protrusion 43 . It is possible to prevent the occurrence of a short circuit via the inner peripheral surface 10a.

In addition, since the accommodating portion 11 also has the function of the concave portion 104 for accommodating the projecting piece portion 54 of the circuit board 50 , there is no need to separately provide a concave accommodating portion on the inner peripheral surface 10 a of the resin outer shell 10 . Therefore, the thickness of the resin outer shell 10 in the radial direction can be secured, and the mechanical strength of the resin outer shell 10 can be easily secured compared to the case where the accommodating portion 11 is formed separately from the recess 104 .

In addition, since the accommodating portion 11 also has the function of the concave portion 104, a soldering iron (not shown) inserted from the opening side of the resin outer shell 10 when connecting the end portion 221 of the coil 22 and the terminal 56 by soldering can be used. A large working space for hand soldering can be secured by the accommodating portion 11, and workability can be improved.

In addition, as described above, the accommodation portion 11 is formed in a trapezoidal shape in which the width in the radial direction becomes narrower toward the outer diameter side when viewed from the axial direction. As a result, the space of the accommodating portion 11 that accommodates part of the peripheral portion 523 of the insulating sheet 52 can be kept small. Therefore, the thickness of the resin outer shell 10 in the radial direction can be secured, and the mechanical strength of the resin outer shell 10 can be secured.

<Modification>
9A and 9B are cross-sectional views of main parts of an electric motor 1A according to a modification of the invention.
Hereinafter, configurations different from those of the first embodiment will be mainly described, and configurations similar to those of the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted or simplified.

As shown in FIGS. 9A and 9B, a lid member 4A of this embodiment differs from that of the first embodiment in that the protrusion 44A has an inclined portion 440. As shown in FIGS. The inclined portion 440 has a cross-sectional area perpendicular to the axial direction of the projecting portion 44A that decreases toward the electronic component 51 from the disk portion 42A. The inclined portions 440 are provided on the four side surfaces of the projecting portion 44A so that the projecting portion 44A has a truncated quadrangular pyramid shape with the contact portion 441 as the apex. The shape of the protrusion 44A is not limited to the truncated quadrangular pyramid shape, and may be, for example, a truncated cone shape.

As shown in FIGS. 9A and 9B, the insulating sheet 52A has a peripheral edge portion 523 that shields the lead portions 411 of the electronic component 51 from the projecting portion 44A. The inclined portion 440 can increase the insulation distance, particularly the creeping distance B, from the lead portion 511 to the projection portion 44A. As a result, the insulating sheet 52A can be made thin in the axial direction, so that the size of the electric motor 1B can be reduced in the axial direction.

In each of the embodiments described above, the case where the cover member 4, 4A has one protrusion 44 has been described, but the present invention is not limited to this, and a plurality of protrusions 44 may be provided according to electronic components and the like. For example, if there are two or more electronic components with different heights, a plurality of projections corresponding to the respective heights may be provided. may be formed so as to protrude into the two electronic components at .

Further, in the present embodiment described above, the protrusion 44, which is a metal component that is in thermal contact with the electronic component 51, is formed integrally with the lid member 4, but the present invention is not limited to this. For example, instead of the protrusion 44 integrated with the lid member 4 , a metal block for heat transfer that is separate from the lid member 4 may be arranged between the lid member 4 and the electronic component 51 . In this case, the portion of the lid member 4 that contacts the metal block becomes the contact portion 441 that thermally contacts the electronic component 51 of the circuit board 5 .

Further, in the above-described embodiment, a load (torque) is provided at one end of the rotating shaft 6 of the electric motor 1, and a single-shaft motor that outputs an output in response to the load has been described as an example. A double-shaft motor may be used in which a load (torque) is provided at both ends and an output is generated in response to the load.

In addition, in the present embodiment described above, the circuit board 5 has a disk shape along the inner peripheral surface 10a of the resin outer shell 10, but it is of course not limited to this. It may have any shape as long as it can be supported on the mounting surface 9, and may be rectangular, for example.

Furthermore, in the above embodiment, the rotor main body 30 has a three-part structure consisting of the outer core 32, the insulating member 33, and the inner core 34. However, it is not limited to this, and may be composed of a single core member. good too.

DESCRIPTION OF SYMBOLS 1, 1A... Electric motor 4, 4A... Lid member 10... Resin outer shell 10a... Inner peripheral surface 10b... Outer peripheral surface 101... Opening edge part 104... Recessed part 11... Accommodating part 2... Stator 21... Stator core 3... Rotor 31 Permanent magnet portion 32 Outer peripheral iron core 33 Insulating member 34 Inner peripheral iron core 41 First bearing accommodating portion 42, 42A Disk portion 43, 43A Annular projection 44, 44A Projection 420, 420A Axial positioning part 430, 430A Radial positioning part 5 Circuit board 51 Electronic component 52, 52A Insulating sheet 54 Protruding piece 511 Lead part 523 Peripheral edge 6 Rotating shaft

C...Axis center

Claims (8)

a cylindrical resin shell having an open end on one end side in the axial direction;
a stator comprising a coil and a stator core integrally formed with the resin shell;
a rotor arranged on the inner diameter side of the stator;
a lid member that covers the opening end of the resin shell;
a circuit board having an electronic component disposed in an internal space covered with the resin shell and the lid member;
an insulating sheet having a peripheral edge positioned outside the peripheral edge of the electronic component when viewed in the axial direction;
a housing portion formed by a recess that is recessed from the inner peripheral surface side of the resin outer shell toward the outer diameter side thereof and that stores a part of the peripheral edge portion of the insulating sheet ,
The circuit board further has a projecting piece having a terminal projecting from the peripheral edge of the circuit board toward the outer diameter side and connected to an end of the coil,
The projecting piece portion is accommodated in the accommodating portion
Electric motor. The electric motor according to claim 1,
The peripheral edge portion of the insulating sheet and the inner wall surface of the accommodating portion of the resin outer shell are separated from each other. The electric motor according to claim 1 or 2,
The electric motor has a rotating shaft to which the rotor is fixed,
The circuit board is formed in a disc shape having a central hole through which the rotating shaft passes,
The electric motor, wherein the insulating sheet is spaced apart from the center hole. The electric motor according to any one of claims 1 to 3 ,
The electric motor, wherein the area of the cross section of the accommodating portion along the circumferential direction of the cylindrical resin shell is smaller on the outer peripheral surface side of the resin shell than on the inner peripheral surface side of the resin shell. The electric motor according to any one of claims 1 to 4 ,
The electric motor, wherein the circuit board has an insulating sheet positioning portion indicating the arrangement position of the insulating sheet. The electric motor according to any one of claims 1 to 5 ,
The insulating sheet has a heat transfer portion sandwiched between the electronic component and the lid member,
The lid member has a contact portion that thermally contacts the heat transfer portion of the insulating sheet. The electric motor according to claim 6 ,
The lid member further includes a protrusion projecting toward the electronic component and having the contact portion on a surface facing the electronic component. The electric motor according to claim 7 ,
The heat transfer portion of the insulating sheet is sandwiched between the electronic component and the protrusion.

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