Electric motor

Abstract

Provided is an electric motor that improves assemblability while preventing a conductive member from falling off. The electric motor according to one aspect of the present invention includes: a rotor; a shaft that is arranged along the rotation axis of the rotor and to which the rotor is fixed; a first bearing that is provided on one end side of the shaft; a second bearing that is provided on the other end side of the shaft; a housing that includes an annular portion and end faces formed at both ends of the annular portion in the direction of the rotation axis, and houses the rotor inside covered by the annular portion and the end faces; a conductive member that is electrically connected to the first bearing and the second bearing; and legs that project radially outward from the outer peripheral surface of the housing. The legs include mounting holes to which vibration-proof members will be attached. The mounting holes include fixing portions to which the conductive member will be fixed.

Description

Technical Field

[0001] The present invention relates to an electric motor including two bearing seats and a conductive member for electrically connecting these bearing seats. Background Art

[0002] As an electric motor, an inner rotor motor has been conventionally known, in which a columnar rotor including permanent magnets is coaxially arranged on the inner diameter side of a cylindrical stator that generates a rotating magnetic field. This electric motor is used, for example, to rotationally drive a blower installed in an air conditioner.

[0003] When such an electric motor is driven by a PWM inverter that performs high-frequency switching, a potential difference (shaft voltage) is caused between the inner ring and the outer ring of the bearing. When this shaft voltage reaches the dielectric breakdown voltage of the oil film inside the bearing, current flows inside the bearing and electrolytic corrosion is caused in the bearing. To prevent electrolytic corrosion from occurring in the bearing, an electric motor is known in which a conductive member electrically connects a bearing provided on one end side of the electric motor in the rotational axis direction and a bearing provided on the other end side of the electric motor.

[0004] Conventional techniques for fixing a conductive member to the outer peripheral surface of the housing of an electric motor include Patent Document 1. Further, conventional techniques for embedding a conductive member in an electric motor include Patent Document 2.

[0005] Citation List

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-20348

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-121100 Summary of the Invention

[0009] Technical Problem

[0010] Here, if the conductive member is fixed to the outer peripheral surface of the housing of the electric motor, the assemblability of the electric motor can be improved, but there is a possibility that the conductive member may fall off from the outer peripheral surface. On the other hand, if the conductive member is embedded in the electric motor, the conductive member can be prevented from falling off from the electric motor, but since the embedding step is added, the assemblability of the electric motor is reduced.

[0011] In this regard, an object of the present invention is to provide an electric motor that improves assemblability while preventing a conductive member from falling off from the electric motor.

[0012] Technical Solution

[0013] According to one aspect of the present invention, there is provided an electric motor including: a rotor; a shaft disposed along the rotation axis of the rotor, with the rotor fixed to the shaft; a first bearing provided on one end side of the shaft; a second bearing provided on the other end side of the shaft; a housing including an annular portion and end faces formed at both ends of the annular portion, and housing the rotor inside covered by the annular portion and the end faces; a conductive member electrically connecting the first bearing and the second bearing; and legs protruding radially outward from the outer peripheral surface of the housing. The legs include mounting holes to which vibration damping members are attached. The mounting holes include fixing portions to which the conductive member is fixed.

[0014] According to the present invention, it is possible to improve the assemblability while preventing the conductive member from falling off the electric motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is an overall perspective view of the electric motor according to the present invention.

[0016] Figure 2 is a transverse cross-sectional view of the electric motor according to the present invention.

[0017] Figure 3 is a perspective view of the bracket of the electric motor according to the present invention.

[0018] Figure 4 is an overall perspective view of the electric motor according to the present invention, showing Figure 3 the state in which the bracket is removed.

[0019] Figure 5 is a cross-sectional view taken along the Figure 1 slit groove shown.

[0020] Figure 6 is an overall perspective view of the electric motor according to the present invention when viewed from the output side, showing the state in which the vibration damping member and the conductive member are removed.

[0021] Figure 7 is a view showing Figure 6 the state in which the vibration damping member and the conductive member are attached in

[0022] Figure 8 is a Figure 5 perspective view of the conductive member. DETAILED DESCRIPTION

[0023] 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 will be denoted by the same or similar reference numerals. It should be noted that the drawings are schematic and may be different from the actual ones. Therefore, the specific constituent parts should be determined with reference to the following description.

[0024] Further, the embodiments described below illustrate devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the shape, structure, arrangement, etc. of the components as the shape, structure, arrangement, etc. described below. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

[0025] Hereinafter, a motor according to an embodiment of the present invention will be described.

[0026] <Overall Structure of Motor>

[0027] Figures 1 to 5 are views for describing the structure of the motor 1 of the present embodiment. As shown in these figures, the motor 1 is, for example, a brushless DC motor. The motor 1 is used, for example, to rotationally drive a blower installed in an outdoor unit of an air conditioner, although not shown in the figures.

[0028] As Figure 1 and Figure 2 shown, the motor 1 of the present embodiment includes a stator 2, a rotor 3, a motor housing (case, enclosure) 10, a bracket 41, and a conductive member 5.

[0029] Hereinafter, as an example, an inner rotor permanent magnet motor 1 will be described, in which a columnar rotor 3 including a permanent magnet portion 31 is rotatably arranged radially inward along a cylindrical stator 2 that generates a rotating magnetic field.

[0030] <Stator, Rotor, and Motor Housing>

[0031] As Figure 2 shown, the rotor 3 includes an annular permanent magnet portion 31 and a coupling portion 35 arranged on the inner diameter side with respect to the permanent magnet portion 31 and coupling the permanent magnet portion 31 and the shaft 32 to each other. The shaft 32 is arranged along the central axis of the columnar rotor 3 and is fixed to the rotor 3. In the present embodiment, the permanent magnet portion 31 and the coupling portion 35 of the rotor 3 are integrally formed by a resin material mixed with a ferrite magnetic material. After molding, only the permanent magnet portion 31 is magnetized so that the permanent magnet portion 31 serves as a ferrite bonded magnet. Further, the permanent magnet portion 31 is magnetized as a magnet with polar anisotropy, in which the south pole and the north pole appear alternately in the circumferential direction. Thus, a part of the yoke for concentrating the magnetic flux flow of the permanent magnet portion 31 becomes unnecessary, and leakage magnetic flux can be suppressed.

[0032] Note that the permanent magnet portion 31 and the coupling portion 35 may be formed separately. For example, the rotor 3 may be a so-called surface magnet (SPM) rotor in which a plurality of ferrite sintered magnets (corresponding to the permanent magnet portion 31) obtained by sintering powdered ferrite magnetic material in a mold are annularly attached to the outer peripheral surface of a rotor core (corresponding to the coupling portion 35).

[0033] The stator 2 includes: a stator core 21 including a cylindrical yoke portion (not shown) and a plurality of tooth portions (not shown) extending from the yoke portion toward the inner diameter side; and a winding (not shown) wound around the tooth portions via an insulator. Except for the inner peripheral surface of the stator core 21, the stator 2 is covered with a motor housing 10 (main body) formed of resin by integral molding (see Figure 2 and Figure 4 ). Specifically, the motor housing 10 covers the stator 2 including the stator core 21 and the winding, and houses the rotor 3 therein. As shown in Figure 1 and Figure 2 , the stator 2 is disposed on the outer peripheral side (radially outward along the permanent magnet motor 1) of the rotor 3. Further, the stator core 21 of the stator 2 is arranged such that the tooth portions of the stator core 21 face the permanent magnet portions 31 of the rotor 3 in the radial direction. In other words, the stator 2 is arranged such that the annular permanent magnet portions 31 of the rotor 3 face the stator core 21 of the stator 2 in the radial direction.

[0034] The motor housing 10 as the main body can have any shape, but is formed, for example, in a bottomed cylindrical shape having an opening O on one side (opposite to the output side of the shaft 32) in the axial direction of the central axis of the permanent magnet motor 1 (i.e., the rotation axis of the rotor 3 (hereinafter, the rotation axis C)). In the present embodiment, the motor housing 10 includes an annular portion 12, an opening O, and an end face portion (bottom surface) 13 formed at an end on the side opposite to the opening O (output side of the shaft 32). Note that the motor housing 10 does not have to be entirely formed of an insulating material such as resin, and can be partially formed of a metal of a conductive material. Further, the present embodiment illustrates the case where the appearance of the motor housing 10 has a column shape, but the appearance of the motor housing 10 can be a quadrangular prism shape or a hexagonal prism shape.

[0035] The rotor 3 is rotatably disposed on the inner peripheral side of the stator core 21 of the stator 2 with a predetermined gap from the stator core 21. As shown in Figure 2 , Figure 4 and Figure 5 , the annular permanent magnet portions 31 arranged in a ring shape are disposed on the outer side (outer peripheral side) in the radial direction of the rotor 3 so as to face the stator core 21.

[0036] The rotor 3 is fixed to the circumference of the shaft 32. The shaft 32 is rotatably supported (held) by a first bearing 33 and a second bearing 34 fixed to the outer peripheral surface of the shaft 32. Further, the first bearing 33 is housed (held) in a first bearing housing portion 42 described later, and the second bearing 34 is housed (held) in a second bearing housing portion 43 described later, so that the rotor 3 is rotatably supported. The first bearing housing portion 42 and the second bearing housing portion 43 are formed of a magnetic material such as nickel-chromium-based stainless steel.

[0037] <Bearing, bracket, and bearing housing portion>

[0038] As Figure 2 , Figure 4 and Figure 5 shown, the first bearing 33 is fixed to one end side (output opposite side) of the shaft 32 on the inner ring side of the first bearing 33. The second bearing 34 is fixed to the other end side (output side) of the shaft 32 on the inner ring side of the second bearing 34. The first bearing 33 and the second bearing 34 (a pair of bearings) cooperate to rotatably support the shaft 32 and the rotor 3 coupled to the shaft 32. For example, ball bearings are used for each of the first bearing 33 and the second bearing 34.

[0039] The bracket 41 includes a first bearing housing portion 42 formed of a magnetic material and housing the first bearing 33, and a non-magnetic portion 44 (end face portion) formed of a non-magnetic material (e.g., resin). In the motor housing 10 (main body) of the permanent magnet motor 1, the bracket 41 is disposed at one end in the direction of the rotation axis C, that is, on the output opposite side of the shaft 32. The non-magnetic portion (end face portion) 44 of the bracket 41 includes a connecting portion 45 connected to the first bearing housing portion 42 (see Figure 2 , Figure 3 and Figure 5 ). The non-magnetic portion (end face portion) 44 of the bracket 41 is integrally formed with the first bearing housing portion 42, which is a magnetic portion, by insert molding. The non-magnetic portion (end face portion) 44 is connected to the first bearing housing portion 42 at the connecting portion 45.

[0040] The bracket 41 is attached to the end on the output opposite side of the motor housing 10 (main body) using screws to serve as a cover for covering the opening O of the motor housing 10 (main body). Note that the opening O of the motor housing 10 (main body) may be provided toward the output side. In this case, the bracket 41 is not disposed on the output opposite side of the shaft 32 but on the output side of the shaft 32.

[0041] The non-magnetic portion 44 (end face portion) of the bracket 41 is formed in a substantially circular plate shape having a radial outer shape that extends radially to the outer peripheral surface of the motor housing 10. Further, the non-magnetic portion 44 (end face portion) of the bracket 41 and the motor housing 10 together form a resin housing of the permanent magnet motor 1. In addition, the non-magnetic portion 44 includes protrusions 410 that project radially outward relative to the outer peripheral surface of the motor housing 10 when viewed from the direction of the rotation axis C. The protrusions 410 each abut on the base end portion of the leg 107 of the motor housing 10. The leg 107 will be described later. The protrusions 410 of the bracket 41 are arranged to overlap the leg 107 in the direction of the rotation axis C.

[0042] The protrusions 410 of the bracket 41 are formed in the same number (three positions) as the legs 107 provided on the motor housing 10. For example, when viewed from the direction of the rotation axis C, the protrusions 410 are each formed in a trapezoidal shape and each include a screw through-hole 413 penetrating in the direction of the rotation axis C in its central portion.

[0043] Note that the bracket 41 includes a slit groove 416 on the outer surface side exposed to the outside in the assembled permanent magnet motor 1, which is used to provide a conductive member 5 for anti-electrolytic corrosion measures, which will be described later (see Figure 1 and Figure 3 ).

[0044] The slit groove 416 extends radially outward from the central portion of the bracket 41 (the tubular connection portion 45 of the non-magnetic portion 44 described later) to the outer peripheral surface of the bracket 41, and further extends axially from there to the position where it abuts against the motor housing 10.

[0045] The bracket 41 is assembled into the motor housing 10 (main body), and then fixed to the leg-side fastening portion (screw hole) 103 of the leg 107 of the motor housing 10 (see Figure 1 ) via the screw through-hole 413 with screws.

[0046] Furthermore, a first bearing housing portion (bearing seat portion) 42 for housing the first bearing 33 on the inner side (opposite side of the output) of the permanent magnet motor 1 is arranged at the central portion of the disc-shaped bracket 41. The first bearing housing portion 42 is formed, for example, in a substantially bottomed cylindrical shape by stamping. Further, the non-magnetic portion 44 of the bracket 41 includes a tubular connection portion 45 connected to the first bearing housing portion 42 on its inner diameter side (see Figure 2 and Figure 5 ).

[0047] A second bearing housing portion (bearing seat portion) 43 for housing the second bearing 34 on the inner side (output side) of the motor 1 is arranged at the central portion of the output side end of the motor housing 10 (see Figure 2 、 Figure 5 and Figure 6 ). Similar to the first bearing housing portion 42, the second bearing housing portion 43 is formed, for example, in a substantially bottomed cylindrical shape. The second bearing housing portion 43 is arranged radially inward (inner diameter side) with respect to the annular permanent magnet portion 31. The end face portion 13 of the motor housing 10 includes a connection portion 14 connected to the flange portion 432 (described later) of the second bearing housing portion 43.

[0048] As Figure 2 and Figure 5As shown, the first bearing housing portion 42 includes: a tubular portion 421 that radially holds the outer ring side of the first bearing 33; an annular flange portion 422 that extends radially outward (outer peripheral side) from one end of the tubular portion 421 in the direction of the rotation axis C of the rotor 3; and a crown portion 423 that extends radially inward (inner peripheral side) from the other end of the tubular portion 421 in the direction of the rotation axis C. The crown portion 423 covers the other end side of the first bearing 33 in the direction of the rotation axis C. The outer peripheral edge of the annular flange portion 422 is positioned radially inward (inner peripheral side) with respect to the permanent magnet portion 31 along the rotor 3. In other words, the first bearing housing portion 42 is formed so as not to overlap the permanent magnet portion 31 when viewed from the direction of the rotation axis C of the rotor 3.

[0049] Specifically, when viewed from the direction of the rotation axis C, the first bearing housing portion 42 (the bearing seat portion of the bracket 41) is arranged radially inward (inner diameter side) with respect to the permanent magnet portion 31 along the rotor 3. Further, the outer peripheral edge portion (the edge portion on the outer diameter side) of the flange portion 422 of the first bearing housing portion 42 (bearing seat portion) is covered with a resin as a non-magnetic material. Specifically, in the bracket 41, the outer peripheral edge portion of the flange portion 422 of the first bearing housing portion 42 is covered with a non-magnetic portion 44 made of resin.

[0050] As described above, the bracket 41 is formed by the first bearing housing portion (magnetic portion) 42, which is one of a pair of bearing housing portions (bearing seat portions), and the non-magnetic portion 44 (end face portion). The first bearing housing portion (magnetic portion) 42 is arranged radially on the inner diameter side with respect to the permanent magnet portion 31 along the rotor 3, whereby it is possible to prevent the flange portion 422 of the first bearing housing portion 42 serving as a magnetic portion from facing the permanent magnet portion 31 in the direction of the rotation axis C. This makes it possible to suppress the leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing housing portion (magnetic portion) 42. Further, in the first bearing housing portion (magnetic portion) 42, the outer peripheral edge portion of the flange portion 422 that is arranged close to the permanent magnet portion 31 of the rotor 3 is covered with the non-magnetic portion 44. This makes it possible to block the path of the leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing housing portion (bearing seat portion) 42 formed of a magnetic material by the non-magnetic portion 44 formed of a non-magnetic material, whereby the leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing housing portion 42 can be further suppressed.

[0051] Note that this structure for suppressing leakage flux can be applied not only to the first bearing housing portion 42 side, but also to the second bearing housing portion 43 side. At this time, the second bearing housing portion 43 is formed in a shape similar to that of the first bearing housing portion 42, and includes: a tubular portion 431 that radially holds the outer ring side of the second bearing 34; an annular flange portion 432 that extends radially outward from one end of the tubular portion 431 in the direction of the rotation axis C of the rotor 3; and a crown portion 433 that extends radially inward from the other end of the tubular portion 431 in the direction of the rotation axis C. In addition, the second bearing housing portion 43 is arranged on the inner diameter side in the radial direction of the rotor 3 with respect to the permanent magnet portion 31. Further, the outer peripheral edge portion of the flange portion 432 of the second bearing housing portion 43 is covered by the end face portion 13 (connection portion 14) of the resin motor housing 10 that is a non-magnetic material. This makes it possible to suppress the leakage flux flowing from the permanent magnet 31 to the second bearing housing portion 43.

[0052] The non-magnetic portion (end face portion) 44 of the bracket 41 includes a connection portion 45 connected to the first bearing housing portion (bearing seat portion) 42. The connection portion 45 is formed in a substantially tubular shape, and the flange portion 422 of the first bearing housing portion (bearing seat portion) 42 is inserted and fixed to the side surface on the inner diameter side of the tubular connection portion 45. Here, the tubular portion 421 of the first bearing housing portion 42 does not contact (is not covered by) the non-magnetic portion 44 of the bracket 41, and only the outer peripheral edge portion of the flange portion 422 is joined (connected) to the connection portion 45 of the non-magnetic portion 44 so as to be covered by it. Further, a gap portion (air gap) AG1 is formed between the tubular portion 421 of the first bearing housing portion 42 and the tubular connection portion 45 of the non-magnetic portion 44. With this configuration, the deformation of the motor housing 10 due to heat, shock, etc. hardly affects the first bearing 33. In addition, the contact area between the connection portion 45 of the bracket 41 and the flange portion 422 of the first bearing housing portion 42 can be reduced, whereby the heat generated at the winding wound around the stator core 21 can be prevented from being transferred to the first bearing 33 via the bracket 41. This makes it possible to suppress the temperature rise of the first bearing 33 and prevent the first bearing 33 from deteriorating.

[0053] In the present embodiment, the second bearing housing portion 43, which is the other of the pair of bearing housing portions (bearing seat portions), also has a structure similar to that of the first bearing housing portion 42. Specifically, the motor housing 10 is formed in a bottomed cylindrical shape and includes: an annular portion 12 of the motor housing 10, which is integrally formed with the stator 2; and an end face portion 13 of the motor housing 10, which is connected to the end of the annular portion 12 and extends radially inward (inner peripheral side). In addition, the end face portion 13 of the motor housing 10 includes a cylindrical connecting portion 14 connected to the second bearing housing portion 43. In addition, similar to the first bearing housing portion 42, the second bearing housing portion 43, which is the other of the pair of bearing housing portions, includes a tubular portion 431 and a flange portion 432 extending radially outward from the tubular portion 431, and only the outer peripheral edge portion of the flange portion 432 is inserted and fixed to the inner diameter side surface of the connecting portion 14 of the resin housing (motor housing 10). Further, a gap portion (air gap) AG2 is formed between the tubular portion 431 of the second bearing housing portion 43 and the connecting portion 14 of the resin housing (motor housing 10).

[0054] With this configuration, the deformation of the motor housing 10 caused by heat, shock, etc. hardly affects the second bearing 34. In addition, the contact area between the connecting portion 14 of the motor housing 10 and the flange portion 432 of the second bearing housing portion 43 can be reduced, thereby preventing the heat generated at the winding wound around the stator core 21 from being transferred to the second bearing 34 via the resin housing 10. This makes it possible to suppress the temperature rise of the second bearing 34 and prevent the second bearing 34 from deteriorating.

[0055] Further, as described above, the rotor 3 includes a coupling portion 35 to which the shaft 32 is fixed, and which couples the permanent magnet portion 31 and the shaft 32 to each other. The permanent magnet portion 31 is arranged to face the cylindrical stator core 21 radially. The coupling portion 35 is arranged on the inner diameter side of the annularly arranged permanent magnet portion 31. As Figure 2 and Figure 4 shown, the coupling portion 35 includes a recess 36 that is recessed along the axial direction (direction of the rotation axis C) of the rotation axis C. The recess 36 is formed such that the thickness of the coupling portion 35 in the direction of the rotation axis C at the position where the recess 36 is formed is smaller than the thickness of the permanent magnet portion 31 in the direction of the rotation axis C. In addition, the flange portion 422 of the first bearing housing portion 42 is arranged to overlap the recess 36 in the direction of the rotation axis C.

[0056] This makes it possible to form an annular recess 36 recessed toward the direction of the rotation axis C on the rotor 3, such that the flange portion 422 of the first bearing housing portion 42 can be arranged within the recess 36.

[0057] In this way, a part of the first bearing housing portion 42 (flange portion 422) can enter the annular recess 36 that is recessed in the axial direction of the rotation axis C, thereby reducing the thickness of the permanent magnet motor 1 in the direction of the rotation axis C and reducing the size of the permanent magnet motor 1 in the direction of the rotation axis C.

[0058] As Figure 4 shown, at the end portion of the stator 2 on the output opposite side in the direction of the rotation axis C ( Figure 4 the upper end portion in ) there are provided terminal pins 26 electrically connected to the windings (not shown) of the stator core 21, and bosses 27 each serving as a guide when attaching to a substrate (not shown).

[0059] The bracket 41 serves as an insulating cover for preventing the terminal pins 26 from being exposed to the outside of the permanent magnet motor 1.

[0060] In this embodiment, the terminal pins 26 are provided at three positions, and the bracket 41 is attached to the motor housing 10 so as to cover these three positions.

[0061] The bracket 41 includes a cover body 414 attached along the upper end surface of the stator 2 and a fitting portion 415 integrally formed with the cover body 414. The cover body 414 and the fitting portion 415 correspond to the non-magnetic portion 44 (end face portion).

[0062] The cover body 414 is integrally formed in a substantially disc shape. As Figure 3 shown, the fitting portion 415 is formed as an annular protrusion disposed at the outer peripheral edge portion of the cover body 414. The fitting portion 415 is fitted into the end portion of the motor housing 10 on the output opposite side ( Figure 4 the upper end surface of the motor housing 10 in ) in the direction of the rotation axis C, so that the motor housing 10 (main body) and the bracket 41 are aligned with each other, and the first bearing 33 is received in the first bearing housing portion 42 of the bracket 41, as Figure 2 shown.

[0063] <Feature part of the invention>

[0064] One end side of the motor housing 10 (main body) of the motor 1 in the direction of the rotation axis C (the end portion on the output opposite side) includes a plurality of legs 107 protruding radially outward (outer diameter side) from the outer peripheral surface of the tubular motor housing 10 (the outer peripheral surface of the annular portion 12) (see Figure 1 , Figure 2 and Figures 4 to 7 ). For example, three legs 107 are arranged at fixed intervals in the circumferential direction of the motor 1.

[0065] The plurality of legs 107 each project in a trapezoidal shape along the outer diameter direction of the motor 1 and each have a predetermined thickness in the direction of the rotation axis C. Note that any number of legs 107 can be provided, such as two or six legs 107, and the plurality of legs 107 do not have to be arranged at fixed intervals.

[0066] As Figure 1 , Figure 4 and Figure 7 shown, each leg 107 formed in a trapezoidal shape is formed such that the length of the leg 107 in the circumferential direction becomes shorter as it goes outward (outer diameter side) in the radial direction of the motor 1. This makes it possible to ensure the strength of the leg 107 and also to effectively utilize the dead space formed in the leg 107. The dead space will be described later.

[0067] Each leg 107 includes a leg-side fastening portion 103 and a vibration-proof member placement portion 104 in which the vibration-proof member 6 will be arranged. The vibration-proof member placement portion 104 is formed at the central portion of the leg 107 in the circumferential direction of the motor 1.

[0068] Examples of the vibration-proof member 6 include vibration-proof rubber and sleeves, each of which is formed into a hollow tube shape or a cylindrical shape. The vibration-proof member 6 of the present embodiment is formed into a tube shape and includes a central core portion 61, flange portions 62 formed at both ends of the central core portion 61 in the direction of the rotation axis C, and an insertion hole 63 into which a fastening member will be inserted (see Figure 5 and Figure 7 ). Note that when viewed from the direction of the rotation axis C (when viewed from above), the tube-shaped vibration-proof member 6 may have a hexagonal or square shape. A fastening member (not shown) (such as a screw) for attaching the permanent magnet motor 1 to an object (such as the case of an air conditioner) to which the permanent magnet motor 1 will be fixed is inserted into the insertion hole 63 of the vibration-proof member 6 in the direction of the rotation axis C. The vibration-proof member 6 is formed of an elastic material such as ethylene propylene diene monomer rubber (EPDM) or chloroprene rubber (CR).

[0069] The leg-side fastening portion 103 is, for example, a screw hole or an insert nut, and a fastening member (such as a screw) (not shown) will be fastened to the screw hole or the insert nut. The leg-side fastening portion 103 formed in the leg 107 and the screw through-hole 413 formed in the bracket 41 are fastened via a fastening member, whereby the leg-side fastening portion 103 is fixed at a position that does not overlap with the vibration-proof member 6 (vibration-proof member placement portion 104). This makes it possible to effectively utilize the area (dead space) in each leg 107 where the vibration-proof member 6 is not arranged, thereby suppressing an increase in the size of each leg 107.

[0070] The vibration damping member placement portion 104 formed in the leg portion 107 includes: a mounting hole 104A that penetrates in the direction of the rotation axis C, and the central core portion 61 of the vibration damping member 6 will be assembled (attached) to the mounting hole; and a cutout portion 104B that connects the outer edge of the leg portion 107 and the mounting hole 104A to each other to assemble (attach) the vibration damping member 6 to the mounting hole 104A from the outer diameter side. This enables the central core portion 61 of the vibration damping member 6 to be assembled into the mounting hole 104A via the cutout portion 104B.

[0071] In addition, the vibration damping member 6 attached to the vibration damping member placement portion 104 is restricted from moving in the thickness direction (rotation axis C direction) of the leg portion 107 by the flange portion 62 of the vibration damping member 6.

[0072] Note that the vibration damping member placement portion 104 does not have to include the cutout portion 104B connected to the outer peripheral edge of the leg portion 107, and can be merely the mounting hole 104A configured as a through hole that penetrates in the direction of the rotation axis C. In this case, the vibration damping member 6 is inserted into the mounting hole 104A formed as a through hole in the direction of the rotation axis C.

[0073] The vibration damping member placement portion 104 may include a recess 106 that is recessed on one side (output side of the shaft 32) of the leg portion 107 in the direction of the rotation axis C to conform to the shape of the vibration damping member 6. This enables the thickness of the leg portion 107 to be ensured to maintain strength and simplifies the shape of the vibration damping member 6.

[0074] Here, when the motor 1 is driven by a PWM inverter that performs high-frequency switching, the potential of the neutral point of the winding does not become zero, and a voltage called the common-mode voltage is generated. Due to the common-mode voltage, the stray capacitance in the motor 1 causes a potential difference (shaft voltage) between the inner ring and the outer ring of each of the first bearing 33 and the second bearing 34. When the shaft voltage reaches the dielectric breakdown voltage of the oil film in the bearing, current flows inside the bearing and causes electrolytic corrosion in the bearing. To prevent electrolytic corrosion from occurring in the bearing, the motor 1 of the present embodiment includes a conductive member 5 for conducting electricity between the first bearing housing portion 42 and the second bearing housing portion 43 that respectively house the two bearings.

[0075] For example, the conductive member 5 is formed by processing a conductive material into a strip or a wire. In the present embodiment, the conductive member 5 is formed, for example, by stamping a steel plate with a thickness of approximately 0.3 mm into a strip and bending the obtained steel plate along the outer surfaces of the motor housing 10 and the bracket 41 into a square U shape (U shape) (see Figure 5 and Figure 8)。The conductive member 5 allows the first bearing 33 and the second bearing 34 to have the same potential on the outer ring side by electrically connecting the first bearing housing portion 42 that houses the first bearing 33 and the second bearing housing portion 43 that houses the second bearing 34, so that the occurrence of electrolytic corrosion can be suppressed by reducing the potential difference between the inner ring and the outer ring of each bearing.

[0076] The conductive member 5 includes a pair of connecting end portions 51 and 51 connected to the bearing housing portions 42 and 43, a pair of end face side placement portions 52 and 52 arranged on the end face portion of the housing of the motor 1 to extend in the radial direction, and an outer peripheral face side placement portion 53 arranged on the outer peripheral face of the housing of the motor 1 along the direction of the rotation axis C. Note that in this embodiment, an example is shown in which the conductive member 5 is formed of a single bar-shaped member, but a plurality of conductive members can be connected to form the conductive member 5.

[0077] As described above, in the motor 1 of the present embodiment, slit grooves 108 and 416 are respectively formed in the motor housing 10 and the bracket 41 (see Figure 1 and Figures 5 to 7 ). In addition, when the bracket 41 is assembled into the motor housing 10, the slit groove 416 of the bracket 41 and the slit groove 108 formed in the outer surface of the motor housing 10 become continuous.

[0078] As Figure 5 and Figure 7 shown, the conductive member 5 is arranged on the outer surface of the motor 1 so as to extend from the position of the flange portion 422 of the first bearing housing portion 42 to the position of the flange portion 432 of the second bearing housing portion 43 through the slit groove 416 of the bracket 41, the slit groove 105 of the leg portion 107 to be described later, and the slit groove 108 of the motor housing 10. The conductive member 5 is arranged in the slit grooves (416, 105, 108) so that the conductive member 5 can be prevented from protruding from the housing surface of the motor 1 and falling off from the motor 1.

[0079] Here, any one of the three leg portions 107 includes a slit groove (conductive member fixing portion) 105 formed at the position of the minimum distance from the rotation axis C in the mounting hole 104A of the vibration-proof member placement portion 104. The slit groove 105 is a groove having a concave shape, a V shape, etc., and is formed to be continuous with the mounting hole 104A so as to recess inward from the edge of the mounting hole 104A.

[0080] With this configuration, the edge of the mounting hole 104A serves as a guide for guiding the outer peripheral surface side placement portion 53 of the conductive member 5 to the slit groove 105, which is advantageous for positioning the conductive member 5. Further, the slit groove 105 serving as a conductive member fixing portion is formed in the leg portion 107 protruding in the outer diameter direction from the outer periphery of the motor housing 10, so that a deeper groove can be formed than a groove directly provided on the side surface of the motor housing 10, and the conductive member 5 is more difficult to fall off from the motor 1.

[0081] Further, as described above, the vibration-proof member placement portion 104 includes a cutout portion 104B obtained by partially opening a hole in the leg portion 107, so that the outer peripheral surface of the leg portion 107 is continuous with the mounting hole 104A. This makes it possible to easily arrange the conductive member 5 from the outer peripheral side of the leg portion 107 through the cutout portion 104B into the conductive member fixing portion (slit groove) 105 provided in the mounting hole 104A in a manner similar to attaching the vibration-proof member 6 to the mounting hole 104A. In other words, since the conductive member 5 is attached to the conductive member fixing portion 105 so as to be laid from the outside of the motor 1, the conductive member 5 can be easily attached to the motor 1.

[0082] In addition, before assembling the vibration-proof member 6 into the vibration-proof member placement portion 104 (mounting hole 104A) of the leg portion 107, the outer peripheral surface side placement portion 53 of the conductive member 5 is inserted into the above-mentioned slit groove 105 in advance, and then the vibration-proof member 6 is assembled into the vibration-proof member placement portion 104 (mounting hole 104A), so that the movement of the conductive member 5 in the outer diameter direction is restricted by the vibration-proof member 6. Further, the movement of the conductive member 5 in the circumferential direction is restricted by forming the slit groove (conductive member fixing portion) 105 continuous with the mounting hole 104A. Specifically, the vibration-proof member 6 and the slit groove 105 cooperate to restrict the movement of the conductive member 5, thereby preventing the conductive member 5 from falling off the motor 1.

[0083] The connecting end portions 51 and 51 at both ends of the conductive member 5 are bent along the tubular connecting portions (45, 14) of the resin housing and the tubular portions (421, 431) of the bearing seat portions (42, 43), and then press-fitted and fixed to the slit portions AG1 and AG2 formed outside the tubular portions 421 and 431 of the bearing seat portions 42 and 43 (see Figure 1 and Figures 5 to 7 ). With this configuration, by using the slit portions AG1 and AG2, the conductive member 5 for preventing electrolytic corrosion can be easily fixed to the bearing seat portions 42 and 43. In addition, the connecting end portions 51 and 51 of the conductive member 5 are respectively fixed to the flange portions 422 and 432 of the bearing seat portions 42 and 43 in the abutting state, thereby electrically connecting the first bearing 33 and the second bearing 34.

[0084] Note that the means for fixing the two end portions of the conductive member 5 to the bearing seat portion is not limited to the above means. For example, the connecting end portions 51 and 51 of the conductive member 5 can be fixed to the bearing seat portions 42 and 43 with caulking members (not shown).

[0085] Furthermore, the conductive member 5 is not limited to being integrally formed in a square U shape, and only needs to include a placement portion 53 on the outer peripheral surface side, which is fixed to the mounting hole 104A formed in the leg portion 107. For example, if the metal bearing seat portions (the first bearing housing portion 42 and the second bearing housing portion 43) are formed to extend to the outer peripheral surface of the cylindrical motor housing 10, the conductive member 5 only needs to include a placement portion 53 on the outer peripheral surface side along the side surface (the outer peripheral surface of the annular portion 12) of the motor housing 10, and does not need to include a placement portion 52 on the end surface side along the end surface (the end face portions 13 and 44) of the motor 1.

[0086] As described above, the motor 1 includes: a rotor 3; a shaft 32 arranged along the rotation axis C of the rotor 3, with the rotor 3 fixed to the shaft 32; a first bearing 33 provided on one end side of the shaft 32; a second bearing 34 provided on the other end side of the shaft 32; housings 10 and 41 including an annular portion 12 and end face portions 13 and 44 formed at both ends of the annular portion 12 in the direction of the rotation axis C, and housing the rotor 3 inside covered by the annular portion 12 and the end face portions 13 and 44; a conductive member 5 electrically connecting the first bearing 33 and the second bearing 34; and a leg portion 107 protruding radially outward from the outer peripheral surface of the housing 10. The leg portion 107 includes a mounting hole 104A to which the vibration damping member 6 is attached. The mounting hole 104A includes a conductive member fixing portion (slit groove) 105 to which the conductive member 5 is to be fixed.

[0087] This enables the conductive member 5 to be fixed to the motor 1 by using the slit groove (conductive member fixing portion) 105 provided in the mounting hole 104A, whereby the conductive member 5 can be easily attached to the motor 1 and the conductive member 5 can be prevented from falling off the motor 1.

[0088] Note that the conductive member fixing portion 105 provided in the mounting hole 104A does not need to include a slit groove opening at the edge of the mounting hole 104A. In this case, the conductive member 5 is fixed while being clamped between the edge of the circular mounting hole 104A and the vibration damping member 6. In this situation, the conductive member 5 can also be easily fixed by using the mounting hole 104A and the vibration damping member 6 attached to the mounting hole 104A, and the conductive member 5 can be prevented from falling off the motor 1.

[0089] List of Reference Numerals

[0090] 1 Motor

[0091] 10 Motor housing (housing)

[0092] 12 Annular part

[0093] 13 End face part

[0094] 104 Vibration-proof member placement part

[0095] 104A Mounting hole

[0096] 104B Notch part

[0097] 105 Slit groove (conductive member fixing part)

[0098] 107 Leg part

[0099] 2 Stator

[0100] 3 Rotor

[0101] 32 Shaft

[0102] 33 First bearing

[0103] 34 Second bearing

[0104] 41 Bracket

[0105] 44 End face part

[0106] 5 Conductive member

[0107] 53 Outer peripheral surface side placement part

[0108] 6 Vibration-proof member

Claims

1. A motor, comprising: A rotor; A shaft, the shaft being arranged along the rotation axis of the rotor, and the rotor being fixed to the shaft; A first bearing, the first bearing being provided on one end side of the shaft; A second bearing, the second bearing being provided on the other end side of the shaft; A housing, the housing including an annular portion and end faces formed at both ends of the annular portion in the direction of the rotation axis, and housing the rotor inside covered by the annular portion and the end faces; A conductive member, the conductive member being electrically connected to the first bearing and the second bearing; And Legs, the legs protruding radially outward from the outer peripheral surface of the housing, wherein, The legs include mounting holes, and a vibration-proof member is attached to the mounting holes, and The mounting holes include fixing portions, and the conductive member is fixed to the fixing portions, The conductive member is restricted from moving radially outward by the vibration-proof member attached to the mounting holes.

2. The motor according to claim 1, wherein, The conductive member includes an outer peripheral surface side placement portion axially arranged along the rotation axis on the outer peripheral surface of the housing, and The outer peripheral surface side placement portion of the conductive member is fixed to the fixing portion.

3. The motor according to claim 1 or 2, wherein, The fixing portion is a groove formed continuously with the mounting hole.

4. The motor according to claim 3, wherein, The fixing portion is formed at a position having the minimum distance from the rotation axis in the mounting hole.

5. The motor according to claim 1, wherein, A part of the mounting hole on the outer diameter side is open, and the outer peripheral surface of the leg and the mounting hole are continuous.

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