electric motor

Abstract

To provide an electric motor capable of suppressing complication of assembly processes, while preventing a heat transmission member from being fixed to an electronic component in a tilted state within the electric motor.SOLUTION: An electric motor according to one embodiment of the present invention includes a rotator having a rotation shaft, a stator provided on an external diameter side of the rotator, a housing case housing the stator, a circuit board provided in an internal space covered with the housing case, and a heat transmission member forming a heat transmission path between the circuit board and the housing case. On the circuit board, an electronic component and a supporting member are arranged, and the heat transmission member is supported by the electronic component and the supporting member.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an electric motor, and more particularly to a heat dissipation structure for a circuit board built into an electric motor. [Background technology]

[0002] Conventionally, electric motors have been known that include a circuit board inside the motor that controls the rotational drive of the electric motor. This circuit board contains electronic components that generate heat when current is applied, and electric motors that have a heat sink that dissipates the heat generated by the electronic components to the outside of the electric motor are also known.

[0003] For example, Patent Document 1 describes a brushless motor that includes a control board, an IPM (electronic component) that is an inverter, and a heat transfer member, in which the heat transfer member is configured to form a path for dissipating heat generated by the IPM mounted on the control board when current is applied to the IPM outside the case of the brushless motor.

[0004] Patent document 2 also describes a brushless motor that includes a steel plate bracket that holds a bearing and houses and fixes a stator, a circuit board that is placed inside the steel plate bracket and that has heat-generating components (electronic components) mounted on it, a heat-transfer component that is placed between the steel plate bracket and the heat-generating component and that transfers heat generated by the heat-generating component to the steel plate bracket, and a fixing member for fixing the heat-transfer component onto the heat-generating component. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-80653 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-192544 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the heat transfer member is disposed on an IPM, which is an electronic component that generates heat when current is applied. However, part of the lower surface of the heat transfer member is not supported by the electronic component, which may cause the heat transfer member to be fixed at an angle relative to the electronic component during assembly of the motor. This results in a problem of reduced heat transfer and insulation between the electronic component and the heat transfer member.

[0007] On the other hand, in Patent Document 2, the fixing member is composed of an assembly of an engaging portion that fixes the electronic component and a heat transfer component holding portion that is fitted to the heat transfer component, which results in a problem that the assembly process for connecting the heat transfer component holding portion to the engaging portion becomes complicated. Also, since the fixing member is formed to fit the size of the heat transfer component, if the size of the heat transfer component is changed, the fixing member also needs to be reshaped to fit the size of the heat transfer component.

[0008] In view of the above circumstances, an object of the present invention is to provide an electric motor that can prevent a heat transfer member from being fixed in an inclined position relative to electronic components inside the electric motor while suppressing the complexity of the assembly process. [Means for solving the problem]

[0009] In order to achieve the above object, one embodiment of the present invention provides an electric motor comprising: a rotor having a rotating shaft; a stator arranged on the outer diameter side of the rotor; a housing case that houses the stator; a circuit board arranged in an internal space covered by the housing case; and a heat transfer member that forms a heat transfer path between the circuit board and the housing case, wherein electronic components and a support member are arranged on the circuit board, and the heat transfer member is supported by the electronic components and the support member.

[0010] In the electric motor, the heat transfer member is supported by the electronic component disposed on the circuit board and the support member, which allows the heat transfer member to be supported more stably than when the heat transfer member is supported only by the electronic component, and prevents the heat transfer member from being fixed at an angle relative to the electronic component during assembly.

[0011] The electronic component may include a first support surface that supports the heat transfer member, and the support member may include a second support surface that supports the heat transfer member together with the first support surface.

[0012] The second support surface may be formed at a position that does not overlap with the first support surface when viewed in a direction perpendicular to the circuit board.

[0013] The second support surface may be disposed on the outer diameter side of the first support surface.

[0014] The electronic component may have a main body and leads extending from the main body, and the support member may have an outer frame surrounding the outer periphery of the electronic component.

[0015] The outer frame portion may have a regulating portion that regulates the range of resin to be applied to the lead portion, and the regulating portion may be formed in a position that does not overlap with the second support surface when viewed from a direction perpendicular to the circuit board.

[0016] The height of the second support surface from the circuit board may be greater than the height of the restricting portion.

[0017] The outer frame may have a locking portion that abuts against a surface of the main body on which the lead portions are formed. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide an electric motor that can prevent the heat transfer member from being fixed in an inclined state with respect to the electronic components inside the electric motor, while suppressing the complexity of the assembly process. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a partial cross-sectional view of an electric motor according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a main part of an electric motor according to an embodiment of the present invention. [Figure 3] 1A and 1B are diagrams showing a support member of an electric motor according to an embodiment of the present invention, in which (A) is a top view of the support member, and (B) is a side cross-sectional view of the support member. [Figure 4] 1A and 1B are diagrams showing a support member of an electric motor according to an embodiment of the present invention, in which (A) is a top perspective view of the support member, and (B) is a bottom perspective view of the support member. [Figure 5] FIG. 10 is a cross-sectional view of a main part of a comparative example electric motor that does not have a support member. DETAILED DESCRIPTION OF THE INVENTION

[0020] Next, an embodiment 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 the actual product. Therefore, specific components should be determined by taking the following description into consideration.

[0021] Furthermore, the embodiments shown below are merely examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the shape, structure, arrangement, etc. of the components to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims.

[0022] 1 is a partial cross-sectional view of an electric motor 1 according to an embodiment. The electric motor 1 of this embodiment is used, for example, as a drive source for a blower fan mounted in an indoor unit of an air conditioner.

[0023] [Overall configuration of the electric motor] The electric motor 1 includes a stator 2 (stator core 21), a rotor 3, a housing case 10, a support member 4, and a base plate portion 5.

[0024] In the following, an inner rotor brushless DC motor in which a cylindrical rotor 3 having permanent magnet portions 32 is rotatably arranged radially inside a cylindrical stator 2 that generates a rotating magnetic field will be described as an example of the electric motor 1. However, the electric motor is not limited to this, and may be, for example, an outer rotor brushless DC motor, an AC motor, or another electric motor.

[0025] In the following description, the axis C of the rotating shaft 6 is also the central axis of the electric motor 1, i.e., the rotation axis of the rotor 3. The radial direction is the direction that passes through the axis C and is perpendicular to the axial direction. The inner diameter side is the inside in the radial direction, and the outer diameter side is the outside in the radial direction. Furthermore, the circumferential direction is the direction of rotation around the axis C.

[0026] (rotor) The rotor 3 has a rotor body 31, a permanent magnet section 32, and a rotating shaft 6. The rotor body 31 is a laminate of plates made of a soft magnetic material, such as a plurality of electromagnetic steel sheets. The permanent magnet section 32 is fixed in an annular shape to the outer circumferential surface of the rotor body 31, and the rotating shaft 6 is fixed to the inner circumferential surface of the rotor body 31 by press-fitting, caulking, or the like. This causes the rotating shaft 6 to rotate integrally with the rotor body 31.

[0027] The rotor 3 is a surface magnet type in which a permanent magnet section 32 is fixed in an annular shape to the outer circumferential surface. The permanent magnet section 32 is formed in an annular shape by a plurality of permanent magnets (e.g., 8 or 10 pieces) so that the north and south poles appear alternately in the circumferential direction. The permanent magnet section 32 is typically formed from a sintered metal such as an Nd-Fe-B alloy, but may also be a plastic magnet formed in an annular shape by solidifying magnetic powder with resin. The permanent magnet section 32 is not limited to a surface magnet type in which a permanent magnet is fixed to the outer circumferential surface of the rotor body 31, but may also be an embedded magnet type in which, for example, a plurality of plate-shaped permanent magnets are embedded in the rotor body 31.

[0028] (stator) The stator 2 has a stator core 21, coils 22, and insulators 23. The stator core 21 is a laminate of plates made of a soft magnetic material, such as a plurality of electromagnetic steel sheets. The stator core 21 has an annular yoke portion and a plurality of teeth protruding inward from the yoke portion. A coil 22 is wound around each tooth of the stator core 21 via an insulator 23. The plurality of coils 22 includes coils corresponding to three phases, namely, U phase, V phase, and W phase. These coils are connected to each other, for example, at an electrical neutral point (N point). The outer peripheral surface of the stator 2 (stator core 21) is covered by a housing case 10 (see FIG. 1). The stator core 21 of the stator 2 is disposed radially opposite a permanent magnet portion 32 of the rotor 3 with a gap (magnetic gap) between them.

[0029] (Storage case) The housing case 10 holds a first bearing 71 and a second bearing 81 (described below) that support the rotating shaft 6, and houses and fixes the stator 2. The housing case 10 is divided into a first housing case 11 and a second housing case 12 in the axial direction of the rotating shaft 6. The first housing case 11 is provided on the output end 61 side of the rotating shaft 6, and the second housing case 12 is provided on the anti-output end 62 side of the rotating shaft 6. The first housing case 11 on the output end 61 side is formed in a cylindrical shape with a bottom, and has a flange 111 at the end on the opening side of the first housing case 11. A portion of the stator 2 is inserted into this first housing case 11 along the axial direction of the rotating shaft 6. A first bearing accommodating portion 113 (described later) having a bottomed cylindrical shape and a smaller diameter than the bottom surface 112 is formed in the center of the bottom surface 112 of the first accommodating case 11, protruding axially toward the output end portion 61, and the first bearing 71 is held in the first bearing accommodating portion 113.

[0030] The second housing case 12 on the anti-output end 62 side is formed in a cylindrical shape with a bottom, similar to the first housing case 11, and has a flange 121 at the end on the open side of the second housing case 12. This second housing case 12 is arranged so as to cover the remaining portion of the stator 2 and the circuit board 51 that is arranged on the anti-output end 62 side in the axial direction of the rotating shaft 6 of the stator 2, and the flange 121 of the second housing case 12 is fastened to the flange 111 of the first housing case 11 with fastening members 14. A second bearing housing portion 123 (see FIG. 2 ) with a bottom and a cylindrical shape is formed in the center of the bottom surface 122 of the second housing case 12, and has a smaller diameter than the bottom surface 122 and protrudes toward the anti-output end 62 side in the axial direction, and the second bearing 81 is held in the second bearing housing portion 123.

[0031] The first housing case 11 and the second housing case 12 are formed by, for example, pressing a metal plate.

[0032] (bearings) 1, the first bearing 71 is a ball bearing having an outer ring 711, an inner ring 712, and a plurality of balls 713. The second bearing 81 is a ball bearing having an outer ring 811, an inner ring 812, and balls 813.

[0033] The outer ring 711 of the first bearing 71 is fixed to the first housing case 11 (first bearing housing portion 113), and the inner ring 712 of the first bearing 71 is fixed to the output end 61 side of the rotating shaft 6. The outer ring 813 of the second bearing 81 is fixed to the second housing case 12 (second bearing housing portion 123), and the inner ring 812 of the second bearing 81 is fixed to the anti-output end 62 side of the rotating shaft 6. As a result, the rotating shaft 6 is supported by the first bearing 71 and the second bearing 81 so as to be rotatable around the axis C with respect to the housing case 10.

[0034] FIG. 2 is a cross-sectional view of a main part of the electric motor 1 according to the embodiment of the present invention.

[0035] (bearing housing) 1, the first bearing accommodating portion 113 accommodates the first bearing 71. The first bearing accommodating portion 113 has a generally cylindrical shape centered on the axis C, and accommodates the first bearing 71 therein. The second bearing accommodating portion 123 accommodates the second bearing 81. The second bearing accommodating portion 123 has a generally cylindrical shape centered on the axis C, and accommodates the second bearing 81 therein. 2, the second bearing accommodating portion 123 is formed by pressing the accommodating case 10. As a result of forming the second bearing accommodating portion 123 by pressing, the second accommodating case 12 has a recess 124 provided so as to surround the outer periphery of the second bearing accommodating portion 123. The recess 124 is formed such that the bottom surface 122 of the second accommodating case 12 is recessed in an annular shape toward the output end portion 61 side.

[0036] 3A and 3B are diagrams showing a support member 4 of the electric motor 1 according to the embodiment of the present invention, in which (A) is a top view of the support member 4 and (B) is a side cross-sectional view of the support member 4. FIG.

[0037] (Board part) As shown in FIG. 2 , the substrate unit 5 includes a circuit board 51, an electronic component 52 that generates heat when current is applied and is mounted on the surface of the circuit board 51 (the surface on the side opposite the output end 62 of the rotating shaft 6), and a lead portion 522 mounted on the surface of the circuit board 51. The circuit board 51 has a central hole 50 through which the rotating shaft 6 passes and is formed in a generally circular plate shape. The circuit board 51 is supported by a board support base (not shown) provided within the casing 10. The circuit board 51 is electrically connected to the end 24 of each coil 22. The circuit board 51 is electrically connected to the end 221 of the coil 22, thereby electrically connecting the electronic component 52 and each coil 22, and it becomes possible to supply a drive signal output from the electronic component 52 to each coil 22.

[0038] Electronic component 52 is disposed on circuit board 51 and has upper surface portion 523 as a first support surface that supports heat transfer member 91 (described later) (see FIG. 3). Electronic component 52 also has main body portion 521 having upper surface portion 523, and lead portions 522 formed on the outer periphery of main body portion 521.

[0039] As shown in FIG. 3, the main body 521 is a package made of synthetic resin that houses a semiconductor element, and the lead portions 522 are a plurality of metal external terminals that electrically connect the semiconductor element to the circuit board 51. The upper surface portion 523 is the upper surface side (the surface opposite to the output end portion 62) of the main body portion 521. When the electronic component 52 is mounted on the circuit board 51, the upper surface portion 523 is approximately parallel to the circuit board 51 and supports the heat transfer member 91. The lead portion 522 is provided on one side surface 524 that forms the outer periphery of the main body portion 521 .

[0040] The electronic components 52 that generate heat when energized are primarily semiconductor components such as power supply power ICs and ICs for controlling motor drive current, but may also include passive components such as capacitors. In addition to the electronic components 52, other components such as a connector component 53 that connects to a power cable (not shown) are mounted on the circuit board 51. The power cable is connected to a power supply (not shown) through a cable insertion portion 13 (see FIG. 1) formed in a part of the housing case 10.

[0041] (heat transfer material) 3(A) and 3(B) form a heat transfer path between the circuit board 51 on which the electronic components 52 are arranged and the housing case 10. The heat transfer member 91 is a block-shaped component made of a metal material with high thermal conductivity, such as aluminum or copper. The heat transfer member 91 transfers heat from the electronic components 52, which is transferred from the heat dissipation sheet 92, to the adhesive member 93, and dissipates the heat from the second housing case 12 to the outside (outside the electric motor 1). As shown in FIG. 3(B), the adhesive member 93 is a heat-conductive adhesive that bonds the top surface 911 of the heat transfer member 91 to the bottom surface 122 of the second housing case 12, and transfers the heat transferred from the heat transfer member 91 to the housing case 10. As shown in FIG. 3(A), the area of the heat transfer member 91 when viewed in a direction perpendicular to the circuit board 51 is preferably larger than the area of the upper surface 523 of the electronic component 52.

[0042] 3(B), the heat dissipation sheet 92 transfers heat generated by the electronic components 52 to the lower surface 912 of the heat transfer member 91. The heat dissipation sheet 92 is a flexible and adhesive rectangular heat transfer member made of a material such as silicon.

[0043] Heat dissipation sheet 92 has a larger area than heat transfer member 91 when viewed in a direction perpendicular to circuit board 51 (the direction of the rotation axis of electric motor 1). This allows insulating heat dissipation sheet 92 to be interposed over the entire opposing surfaces of electronic component 52 and heat transfer member 91, which face each other, thereby ensuring electrical insulation between electronic component 52 and heat transfer member 91.

[0044] Furthermore, since the heat dissipation sheet 92 has an area larger than that of the heat transfer member 91 when viewed from a direction perpendicular to the circuit board 51 (the direction of the rotational axis of the electric motor 1), the heat generated by the electronic component 52 can be transferred to the heat transfer member 91 more efficiently than when the heat dissipation sheet 92 has an area smaller than that of the heat transfer member 91.

[0045] Furthermore, when the first housing case 11 and the second housing case 12 are fitted together, the heat dissipation sheet 92 comes into close contact with the heat transfer member 91 and the electronic component 52, and at the same time, the force pressing the heat transfer member 91 against the electronic component 52 is released by the deformation of the heat dissipation sheet 92. This ensures a stable thermal connection between the heat transfer member 91 and the electronic component 52, improving heat transfer, and also prevents the electronic component 52 and the circuit board 51 from being damaged by the force applied in the axial direction from the heat transfer member 91.

[0046] The adhesive member 93 not only bonds the casing 10 and the heat transfer member 91 together, but also absorbs variations in the axial positions of the casing 10 and the heat transfer member 91 due to deformation of the adhesive member 93 before solidification. Furthermore, when the first housing case 11 and the second housing case 12 are fitted together, the adhesive member 93 adheres the housing case 10 and the heat transfer member 91 together, and at the same time, the adhesive member 93 dissipates the pressing force from the housing case 10 to the heat transfer member 91 by deforming the adhesive member 93. This ensures a stable thermal connection between the housing case 10 and the heat transfer member 91, improving heat transfer, and also prevents the electronic components 52 and the circuit board 51 from being damaged by the force applied in the axial direction from the housing case 10.

[0047] 4A and 4B are diagrams showing the support member 4 of the electric motor 1 according to the embodiment of the present invention, in which (A) is a perspective top view of the support member 4 and (B) is a perspective bottom view of the support member 4. FIG.

[0048] (support member) As shown in FIGS. 3A and 3B, the support member 4 is disposed on the circuit board 51. The support member 4 has a support surface portion 41 (second support surface) that supports the heat transfer member 91. The support surface portion 41 (second support surface) of the support member 4 supports the heat transfer member 91 together with the upper surface portion 523 (first support surface) of the electronic component 52. In other words, the heat transfer member 91 is supported by the upper surface portion 523 (first support surface) of the electronic component and the support surface portion 41 (second support surface) of the support member 4. The support member 4 of this embodiment is approximately rectangular.

[0049] The support member 4 is, for example, an injection-molded body of synthetic resin such as PBT (polybutylene terephthalate). Furthermore, the support member 4 can ensure physical strength and heat resistance by mixing glass filler into the synthetic resin.

[0050] The support member 4 has an outer frame portion 40 that surrounds the outer periphery of the electronic component 52 (see FIG. 3(A)). Furthermore, the outer frame portion 40 has a first frame portion 401, a second frame portion 402, a third frame portion 403, and a fourth frame portion 404, and inside the outer frame portion 40, a space portion 400 is formed by the above four frame portions that surround the electronic component 52 (see FIG. 4).

[0051] 4, the outer frame 40 has a rectangular shape, with the first frame 401 and the third frame 403 corresponding to the long sides and the second frame 402 and the fourth frame 404 corresponding to the short sides. Also, as shown in FIG. 3, the first frame 401 and the third frame 403 face each other on two long sides of the outer periphery of the electronic component 52, and the third frame 403 and the fourth frame 404 face each other on the remaining two short sides.

[0052] The support member 4 has a plurality of support base portions 410 formed to protrude outward from the first frame portion 401 of the outer frame portion 40 (see FIG. 4). Each support base portion 410 has a roughly rectangular parallelepiped shape and has a support surface portion 41 on the heat transfer member 91 side that supports the heat transfer member 91. The height (second height H2) of the support surface portion 41 from the upper surface of the circuit board 51 is roughly equal to the height of the upper surface portion 523 of the electronic component 52 from the upper surface of the circuit board 51 (i.e., the thickness of the electronic component 52). In this embodiment, the height of the support surface portion 41 from the upper surface of the circuit board 51 is slightly lower than the height of the upper surface portion of the electronic component 52 from the upper surface of the circuit board 51. Furthermore, a lower surface 912 of the heat transfer member 91 supported by the upper surface portion 523 and the support surface portion 41 is parallel to the circuit board 51.

[0053] 3(A), the support surface portion 41 (second support surface) of the support member 4 is provided at a position that does not overlap with the upper surface portion 523 (first support surface) of the electronic component 52 when viewed from a direction perpendicular to the circuit board 51 (the direction of the rotation axis of the electric motor 1). Furthermore, the support base portion 410 having the support surface portion 41 is preferably provided symmetrically with respect to the center of the first frame portion 401 in the longitudinal direction. This allows the heat transfer member 91 to be stably supported.

[0054] 4(A) and 4(B), the support base 410 having the support surface 41 is divided into four locations along the length of the first frame 401. This makes it possible to suppress the occurrence of sink marks (depressions caused by volumetric shrinkage after molding) in the support surface 41 compared to when support bases with lengths corresponding to multiple units are integrally provided along the first frame 401, thereby suppressing a decrease in the dimensional accuracy of the support surface 41 in the height direction. In addition, a hole 411 is formed in the center of each support base portion 410, penetrating the support base portion 410 in the height direction, as a recessed portion to further suppress a decrease in the dimensional accuracy of the support surface portion 41 in the height direction due to sink marks.

[0055] The support member 4 is disposed in correspondence with the mounting position of the electronic component 52 on the circuit board 51, and is disposed so that the outer frame portion 40 surrounds the outer periphery of the electronic component 52. In this embodiment, the support surface portion 41 (second support surface) of the support member 4 is disposed radially outer than the top surface portion 523 (first support surface) of the electronic component 52. Also, as shown in FIG. 2, the support surface portion 41 of the support member 4 is disposed radially outer than the recess 124 formed in the second housing case 12.

[0056] As shown in FIG. 3B , the outer frame 40 has restricting portions 42 that face the lead portions 522 of the electronic component 52. The restricting portions 42 restrict the application range of the resin W that is applied to the lead portions 522. In this embodiment, the third frame 403, a non-contact surface forming portion 463 of the second frame 402 (described later), and a non-contact surface forming portion 464 of the fourth frame 404 (described later) function as the restricting portions 42. The restricting portions 42 are formed so that a small gap is formed between the restricting portions 42 and the lead portions 522 when the support member 4 is placed on the circuit board 51. Furthermore, the restricting portions 42 are formed in a position that is not adjacent to the support base 410 having the support surface portion 41.

[0057] As shown in Figures 3 and 4, the second height H2, which is the height of the support surface portion 41 from the circuit board 51, is formed to be higher than the first height H1, which is the height of the restriction portion 42 from the circuit board 51.

[0058] The second frame portion 402 has, on its surface facing the electronic component 52, a contact surface 451 that contacts one side surface of the short side of the main body portion 521 of the electronic component 52, and a non-contact surface 461 that does not contact the one side surface. The second frame portion 402 also has a contact surface forming portion 453 on which the contact surface 451 is formed, and a non-contact surface forming portion 463 on which the non-contact surface 461 is formed. The fourth frame portion 404 also has, on its surface facing the electronic component 52, a contact surface 452 that contacts the other side surface of the short side of the main body portion 521 of the electronic component 52, and a non-contact surface 462 that does not contact the other surface. The fourth frame portion 404 has the contact surface forming portion 454 on which the contact surface 452 is formed, and the non-contact surface forming portion 464 on which the non-contact surface 462 is formed.

[0059] The abutment surface forming portion 454 has an abutment upper surface portion 471 formed on the same plane as the support surface portion 41, and an inclined portion 472 formed between the abutment upper surface portion 471 and the non-abutment surface forming portion 464, which have different heights from the circuit board 51. The abutment upper surface portion 471 may be molded integrally with the support surface portion 41, as shown in FIG. 4(A). The shape of the abutment inclined portion 472 is formed at an acute angle from the non-abutment surface forming portion 464 toward the abutment upper surface portion 471, but is not limited to this, and may be formed at a right angle. Although not shown, the abutment surface forming portion 453, like the abutment surface forming portion 454, has the abutment upper surface portion 471 and an inclined portion 472 connecting the abutment upper surface portion 471 and the non-abutment surface forming portion 463.

[0060] In this embodiment, when the support member 4 is placed on the circuit board 51, the height of the abutment surface forming portion 453 (abutment upper surface portion 471) of the second frame portion 402 from the circuit board 51 and the height of the abutment surface forming portion 454 (abutment upper surface portion 471) of the fourth frame portion 404 from the circuit board 51 are both set to the same height as the second height H2, which is the height of the support surface portion 41. In other words, the abutment surface forming portion 453 of the second frame portion 402 and the abutment surface forming portion 454 of the fourth frame portion 404, together with the support surface portion 41 formed on the first frame portion 401, support the heat transfer member 91.

[0061] Furthermore, the restricting portion 42 is formed so that its height from the circuit board 51 is a first height H1 when the support member 4 is placed on the circuit board 51. Specifically, the height of the third frame portion 403 from the circuit board 51, the height of the non-contact surface forming portion 463 of the second frame portion 402 from the circuit board 51, and the height of the non-contact surface forming portion 464 of the fourth frame portion 404 from the circuit board 51 are all set to the first height H1. The non-contact surface forming portion 463 of the second frame portion 402, the non-contact surface forming portion 464 of the fourth frame portion 404, and the third frame portion 403 all function as restricting portions 42 that restrict the application range of the resin W that is applied to the lead portions 522.

[0062] Here, it is preferable that the first height H1 of the restricting portion 42 is greater than the height of the lead portion 522. By making the first height H1 of the restricting portion 42 greater than the height of the lead portion 522, the lead portion 522 can be sufficiently covered with the resin W, and insulation can be ensured, even if the resin W has a height that does not exceed the first height H1 of the restricting portion 42. The applied height of the resin W is equal to or greater than the height that can cover the lead portion 522, and is set to be equal to or less than the first height H1 here.

[0063] The outer frame 40 has locking portions 43 that come into contact with the side surfaces 524 of the main body 521 on which the lead portions 522 are formed. In this embodiment, as shown in FIGS. 3(B) and 4(A) and (B), the locking portions 43 are provided on the inside of the outer frame 40 and are formed as protrusions that protrude inward. The locking portions 43 are provided on the second frame 402 and the fourth frame 404. The locking portions 43 come into contact with the side surfaces 524 of the main body 521 on which the lead portions 522 are formed, thereby maintaining a distance between the third frame 403 of the outer frame 40 and the lead portions 522 of the electronic component 52, and ensuring an appropriate area for application of the resin W.

[0064] The position where locking portion 43 abuts against side surface 524 of main body portion 521 will be described in more detail. As shown in FIG. 3(B), locking portion 43 is located below lead portion 522 extending from side surface 524 of main body portion 521. Locking portion 43 is formed in a tapered shape such that the protruding height gradually increases from circuit board 51 toward heat transfer member 91. Therefore, when electronic component 52 is placed on circuit board 51 and then support member 4 is attached from above, locking portion 43 can be positioned so as to slip under lead portion 522 while reducing the load on lead portion 522, and locking portion 43 can abut against side surface 524 of main body portion 521.

[0065] As shown in FIG. 4(A), the support member 4 has a protrusion 44 on the fourth frame portion 404. The protrusion 44 is provided to protrude from the fourth frame portion 404 toward the outside of the outer frame portion 40. The protrusion 44 functions as an incorrect attachment prevention portion that prevents the support member 4 from being attached to the electronic component 52 in the wrong orientation. For example, if the orientation in which the support member 4 is to be fitted is different from the actual intended orientation (for example, the support member 4 is upside down), the protrusion 44 comes into contact with another electronic component (for example, a capacitor) on the circuit board 51, thereby preventing the support member 4 from being fitted in the wrong orientation.

[0066] [Motor action] According to the electric motor 1, the electronic component 52 and the support member 4 are arranged on the circuit board 51, and the heat transfer member 91 is supported by the upper surface portion 523 (first support surface) of the electronic component 52 and the support surface portion 41 (second support surface) of the support member 4. This allows the heat transfer member 91 to be stably supported, and prevents the heat transfer member 91 from being fixed in an inclined state relative to the electronic component 52 during assembly.

[0067] For example, in a comparative electric motor 1A shown in FIG. 5 that does not have support member 4, heat-transfer member 91A is positioned offset relative to electronic component 52A, resulting in an area on one end of the underside of heat-transfer member 91A that is not supported by electronic component 52A. Therefore, in the comparative electric motor 1A, as shown in the area surrounded by circle A, the support of heat-transfer member 91A and heat-dissipating sheet 92A becomes unstable, and heat-transfer member 91A or heat-dissipating sheet 92A may tilt relative to circuit board 51A and come into contact with circuit board 51A (the two-dot chain line indicates the tilted state of heat-transfer member 91A and heat-dissipating sheet 92A). In this case, if heat-transfer member 91A remains tilted, it becomes difficult to attach casing 10 that covers heat-transfer member 91, which makes assembling electric motor 1A difficult. Furthermore, if heat transfer member 91A were to be fixed in a tilted state inside casing 10, it would be impossible to ensure an insulating distance between circuit board 51A and heat transfer member 91A, and the desired electrical insulation characteristics might not be obtained. Furthermore, tilting heat transfer member 91A reduces the contact area between electronic component 52A and heat transfer member 91A, which face each other across heat dissipation sheet 92A, and increases the thermal resistance between electronic component 52A and heat transfer member 91A, making it difficult to effectively dissipate heat generated by electronic component 52A to the outside of motor 1A.

[0068] In contrast, according to the present embodiment, the support member 4 supports, by the support surface portion 41, at least a part of the region of the lower surface 912 of the heat transfer member 91 that is not supported by the upper surface portion 523 of the electronic component 52. This prevents the heat transfer member 91 and the heat dissipation sheet 92 from being tilted with respect to the circuit board 51, even if the heat transfer member 91 is disposed at an offset position with respect to the electronic component 52. Furthermore, by preventing the heat transfer member 91A from being tilted, as described above, it is possible to obtain the desired electrical insulation characteristics and heat dissipation characteristics of the electronic component 52 (in other words, it is easy to transfer heat from the electronic component 52 to the housing case 10), and it is also possible to improve the ease of assembly.

[0069] Furthermore, according to this embodiment, the heat transfer member 91 can be stably supported by the electronic component 52 and the support member 4 during and after assembly, making it easy to increase the size of the heat transfer member 91 and improve heat dissipation, and sufficient heat dissipation is possible even when the electric motor 1 is made to have a high output.

[0070] Furthermore, according to this embodiment, even if the shape or size of heat transfer member 91 is changed, lower surface 912 of heat transfer member 91 can be supported without changing support member 4. Therefore, there is no need to change the shape of support member 4 to match the size of heat transfer member 91. (In addition, since the step of connecting heat transfer member 91 to support member 4 is not required, it is possible to prevent the support member 4 from making the assembly process of electric motor 1 more complicated.)

[0071] The upper surface portion 523 of the electronic component 52 functions as a first support surface that supports the heat transfer member 91, and the support surface portion 41 of the support member 4 functions as a second support surface that supports the heat transfer member 91, thereby preventing the heat transfer member 91 from being fixed in an inclined position.

[0072] Support surface portion 41 (second support surface) of support member 4 is formed at a position that does not overlap with upper surface portion 523 (first support surface) when viewed from a direction perpendicular to circuit board 51, thereby increasing the area that supports heat transfer member 91 and enabling stable support of heat transfer member 91. Furthermore, by using upper surface portion 523 of electronic component 52 as the support surface for heat transfer member 91, a heat transfer path between electronic component 52 and heat transfer member 91 can be reliably secured, thereby improving heat dissipation from electronic component 52.

[0073] By positioning the support surface portion 41 on the outer diameter side of the upper surface portion 523, even if the heat transfer member 91 is positioned offset toward the outer diameter side relative to the electronic component 52, the heat transfer member 91 can be prevented from being fixed at an angle by the support member 4.

[0074] Here, the second bearing accommodating portion 123 formed in the second housing case 12 is typically formed by press working, as described above. The second bearing accommodating portion 123 is surrounded by an annular recess 124 formed by the press working (see FIG. 2 ). When assembling the electric motor 1, the heat transfer member 91 is placed on the electronic component 52, and then the second housing case 12 is placed axially over the electronic component 52 to sandwich the heat transfer member 91 between the circuit board 51 and the second housing case 12. Thus, the heat transfer member 91 is fixed inside the housing case 10 while being sandwiched between the circuit board 51 and the second housing case 12. At this time, the heat transfer member 91 is pushed into the recess 124 formed in the second housing case 12, and is likely to be positioned toward the outer diameter side of the electric motor 1 (the area not supported by the electronic component 52) (to avoid the recess 124, as shown in FIG. 2 ) relative to the electronic component 52. As a result, the heat transfer member 91 tends to tilt toward the outer diameter side of the electric motor 1 as shown in FIG.

[0075] However, in this embodiment, as shown in FIG. 2, the support surface portion 41 is formed on the first frame portion 401 (the frame portion located farthest from the recess 124 on the outer diameter side), so even if the heat transfer member 91 is positioned biased toward the outer diameter side, which is the area not supported by the electronic component 52 by the recess 124, the support surface portion 41 can support the heat transfer member 91 so that it does not fall over.

[0076] The restricting portion 42 is formed at a position away from the support surface portion 41 on the outer frame portion 40, and restricts the application range of the resin W applied to the lead portions 522, thereby restricting the application range when electrically insulating the lead portions 522, and preventing the resin W from spreading onto the circuit board 51.

[0077] Furthermore, the restricting portion 42 is formed at a position that does not overlap with the support surface portion 41 when viewed from a direction perpendicular to the circuit board 51 (the direction of the rotation axis of the electric motor 1). As a result, even if the resin W is accidentally applied to the upper surface of the restricting portion 42 that restricts the application range of the resin W, the support surface portion 41 is disposed at a position away from the restricting portion 42, so that the flatness of the support surface portion 41 that supports the heat transfer member 91 can be maintained and the heat transfer member 91 can be stably supported.

[0078] Furthermore, because the second height H2 of the support surface portion 41 is higher than the first height H1 of the restricting portion 42, the resin W can be prevented from rising higher than the second height H2. As a result, even if an excessive amount of resin W is applied or even if resin W is applied to the upper surface of the restricting portion 42, the resin W will not rise higher than the upper surface 523 of the electronic component 52. If the height of the restricting portion 42 or the height of the resin W (first height H1) were higher than the second height H2 of the support surface portion 41, a gap that inhibits heat transfer would be generated between the upper surface 523 of the electronic component 52 and the lower surface 912 of the heat-transfer member 91, which could prevent heat generated in the electronic component 52 from being sufficiently transferred to the heat-transfer member 91. In other words, because the second height H2 of the support surface portion 41 is higher than the first height H1 of the restricting portion 42, a heat transfer path from the electronic component 52 to the heat-transfer member 91 is reliably secured, thereby improving heat dissipation from the electronic component 52.

[0079] Outer frame 40 has locking portions 43 that come into contact with side surfaces 524 of main body 521 on which lead portions 522 are formed, which not only makes it easier to position support member 4 on electronic component 52, but also prevents gaps from occurring between electronic component 52 and support member 4. This ensures that the application range of resin W is sufficient, allowing for stable application of resin W and making it easier to ensure electrical insulation.

[0080] Furthermore, the locking portion 43 can prevent a gap from being generated between the electronic component 52 and the support member 4, so that the heat transfer member 91 is stably supported without being tilted by the gap.

[0081] As described above, in this embodiment, the support base portions 410 having the support surface portions 41 are provided at four locations on the first frame portion 401, but this is not limitative and they may be provided at two locations. Even when the first support base portions 410 are provided at the two locations described above, it is preferable that they are provided one at each location symmetrically from the center of the length of the first frame portion 401.

[0082] Furthermore, although the support surface portion 41 is formed in a rectangular shape in the above example, the support surface portion 41 is not limited to this, and may be formed in a circular or elliptical shape.

[0083] Furthermore, in this embodiment, outer frame portion 40 continuously surrounds the outer periphery of electronic component 52, but a portion of outer frame portion 40 may be interrupted. For example, outer frame portion 40 may be interrupted (cut out) at the center in the longitudinal direction of third frame portion 403. In this case, by expanding the third frame portion 403 side of outer frame portion 40, support member 4 can be easily attached.

[0084] Furthermore, in the present embodiment, the case where the heat dissipation sheet 92 is disposed between the electronic component 52 and the support member 4 has been exemplified, but this is not limiting. For example, an adhesive member (not shown) may be interposed between the lower surface 912 of the heat transfer member 91 and the support surface portion 41 of the support member 4. Furthermore, the lower surface 912 of the heat transfer member 91 may be in direct contact with the support surface portion 41 of the support member 4.

[0085] In addition, in the present embodiment, the case where the housing 10 of the electric motor 1 is made of a member obtained by pressing a metal plate has been exemplified, but the present invention is not limited to this. For example, the housing 10 may be made of a member obtained by die-casting a metal such as aluminum. Also, for example, the housing 10 may be made of a resin outer shell having a bottomed cylindrical opening formed therein and integrally molded with the stator core, and a metal bracket that closes the opening of the resin outer shell. [Explanation of symbols]

[0086] 1, 1A…Electric motor 2...Stator 21... Stator core 3...Rotor 32...Permanent magnet section 4...Support member 40...Outer frame 41...Support surface portion (second support surface) 42...Regulatory Department 43...Latching part 44...Protrusion 451, 452…Abutment surface 453, 454...Contact surface forming part 461, 462…Non-contact surface 463, 464...Non-contact surface forming part 400…Space part 5...Board 51...Circuit board 52...Electronic components 521...Main body 522...Lead section 523...Upper surface portion (first support surface) 6...Rotating shaft 91, 91A, 91B...Heat transfer members 912…Bottom surface 92, 92A, 92B...heat dissipation sheet 93...Adhesive material 10...Storage case 11...First containment case 12...Second containment case C…Axis center H1...First height H2: Second height

Claims

1. a rotor having a rotating shaft; a stator disposed on the outer diameter side of the rotor; a housing case that houses the stator; a circuit board disposed in an internal space covered by the housing case; a heat transfer member that forms a heat transfer path between the circuit board and the housing case, an electronic component having a first support surface that supports the heat transfer member and a support member having a second support surface that supports the heat transfer member together with the first support surface are arranged on the circuit board; One surface of the heat transfer member is supported by the electronic component and the support member. Electric motor.

2. 2. The electric motor according to claim 1, The second support surface is formed at a position that does not overlap with the first support surface when viewed in a direction perpendicular to the circuit board. Electric motor.

3. 3. The electric motor according to claim 1 or 2, The second support surface is disposed on the outer diameter side of the first support surface. Electric motor.

4. The electric motor according to any one of claims 1 to 3, The electronic component has a main body and a lead extending from the main body, The support member further has an outer frame portion that surrounds the outer periphery of the electronic component. Electric motor.

5. 5. The electric motor according to claim 4, the outer frame portion has a restricting portion that restricts the range of resin to be applied to the lead portion, The restricting portion is formed at a position that does not overlap with the second support surface when viewed in a direction perpendicular to the circuit board. Electric motor.

6. 6. The electric motor according to claim 5, The height of the second support surface from the circuit board is higher than the height of the restriction portion. Electric motor.

7. The electric motor according to any one of claims 4 to 6, The outer frame portion has a locking portion that abuts against the surface of the main body portion on which the lead portions are formed. Electric motor.

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