Electric Motor

Abstract

Provided is a motor that can be reduced in size along the direction of the rotation axis and that can suppress deformation of the bearing and the bearing seat portion that is generated as the resin housing is deformed. The motor according to one aspect of the present invention includes: a cylindrical rotor; a shaft that is arranged along the rotation axis of the rotor; a cylindrical stator core that is arranged on the outer peripheral side of the rotor; a resin housing that covers the stator core; a bearing that rotatably supports the shaft; and a bearing seat portion that accommodates the bearing. The resin housing includes: an annular portion that is integral with the stator core; and an end face portion that is connected to the end of the annular portion and extends from the annular portion to the inner peripheral side. The end face portion includes a connection portion that is connected to the bearing seat portion. The bearing seat portion includes a tubular portion and a flange portion that extends radially from the end of the tubular portion to the outer peripheral side. The outer peripheral edge portion of the flange portion is fixed to the connection portion of the resin housing.

Description

Technical Field

[0001] The present invention relates to an inner rotor motor including a rotor which is coaxially arranged on the inner diameter side of a cylindrical stator. Background Art

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

[0003] In the motor of Patent Document 1 as such a motor, a bearing seat portion (bearing bracket) holding a bearing is arranged near a rotor in the axial direction of the stator, so that the motor is downsized in the axial direction. Further, the stator core is covered with a molding resin to form a resin case.

[0004] Reference List

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-109861 Summary of the invention

[0007] Technical issues

[0008] Here, in the motor of Patent Document 1, the resin case covering the stator also covers the bearing seat portion. Generally, resin is more susceptible to thermal expansion and contraction than metal, and if the resin case covering the bearing seat portion is deformed due to heat, the bearing seat portion or the bearing is deformed along with the deformation of the resin case, which may reduce the sliding property of the bearing.

[0009] In this regard, an object of the present invention is to provide a motor that can be downsized in the axial direction of a rotation axis and can suppress deformation of a bearing and a bearing seat portion caused by deformation of a resin housing.

[0010] Technical Solution

[0011] According to one aspect of the present invention, there is provided an electric motor, comprising: a cylindrical rotor; a shaft arranged along the rotation axis of the rotor; a cylindrical stator core arranged on the outer peripheral side of the rotor; a resin housing covering the stator core; a bearing rotatably supporting the shaft; and a bearing seat portion accommodating the bearing. The resin housing comprises: an annular portion, which is integral with the stator core; and an end face portion, which is connected to the end of the annular portion and extends from the annular portion to the inner peripheral side. The end face portion comprises a connection portion connected to the bearing seat portion. The bearing seat portion comprises a tubular portion and a flange portion extending from the end of the tubular portion to the outer peripheral side. The outer peripheral edge portion of the flange portion is fixed to the connection portion of the resin housing.

[0012] According to the present invention, the size of the motor can be reduced in the axial direction of the rotation axis, and deformation of the bearing and the bearing seat portion caused by deformation of the resin case can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 1 is an overall perspective view of a permanent magnet motor according to the present invention.

[0014] Figure 2 is a transverse cross-sectional view of a permanent magnet motor according to the present invention.

[0015] Figure 3 is a perspective view of a bracket of a permanent magnet motor according to the present invention.

[0016] Figure 4 is an overall perspective view of a permanent magnet motor according to the present invention, showing Figure 3 The bracket is removed.

[0017] Figure 5 It is along Figure 1 A cross-sectional view of a cross section taken through a slit groove is shown. DETAILED DESCRIPTION

[0018] Next, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the accompanying drawings, the same or similar parts will be represented by the same or similar reference numerals. It should be noted that the accompanying 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.

[0019] Further, the embodiments described below illustrate the devices and methods for implementing the technical concept of the present invention, and the technical concept of the present invention does not specify the shape, structure, arrangement, etc. of the constituent parts as the shape, structure, arrangement, etc. described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the scope of the claim.

[0020] Hereinafter, a motor according to an embodiment of the present invention will be described.

[0021] <Overall structure of the motor>

[0022] Figures 1 to 5 1 is a diagram for describing the configuration 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.

[0023] like Figure 1 and Figure 2As shown, the motor 1 of this embodiment includes a stator 2 , a rotor 3 , a motor housing (shell, body) 10 and a bracket 41 .

[0024] Hereinafter, as an example, an inner rotor permanent magnet motor 1 will be described in which a cylindrical rotor 3 including a permanent magnet portion 31 is rotatably arranged radially inward (inner peripheral side) of a cylindrical stator 2 that generates a rotating magnetic field.

[0025] <Rotor, stator and motor housing>

[0026] like Figure 2 As shown, the rotor 3 includes an annular permanent magnet portion 31 and a coupling portion 35 arranged on the inner diameter side relative to the permanent magnet portion 31 and coupling the permanent magnet portion 31 and the shaft 32 to each other. The shaft 32 is fixed to the cylindrical rotor 3 along the central axis of the rotor 3. In the present embodiment, the permanent magnet portion 31 and the coupling portion 35 of the rotor 3 are formed by integrally molding a resin material mixed with a ferrite magnetic substance. After molding, only the permanent magnet portion 31 is magnetized so that the permanent magnet portion 31 is used as a ferrite bonded magnet. Further, the permanent magnet portion 31 is magnetized into a polar anisotropic magnet in which the south pole and the north pole appear alternately along its circumferential direction. As a result, a part of the yoke for concentrating the magnetic flux flow of the permanent magnet portion 31 becomes unnecessary, and leakage flux can be suppressed.

[0027] 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 a powdered ferrite magnetic substance in a mold are annularly attached to the outer peripheral surface of the rotor core (corresponding to the coupling portion 35).

[0028] The stator 2 includes: a stator core 21 including a cylindrical yoke portion (not shown) and a plurality of teeth (not shown) extending from the yoke portion to the inner diameter side; and a winding (not shown) wound around the teeth via an insulator. The stator core 21 is formed of, for example, silicon steel, which is a soft magnetic material. The stator 2 is covered with a motor housing 10 (see FIG. 1 ) formed of resin by integral resin molding except for the inner circumferential surface of the stator core 21. Figure 2 and Figure 4 Specifically, the motor housing 10 covers the stator 2 including the stator core 21 and the winding. Figure 1 and Figure 2 As shown, the stator 2 is arranged on the outer peripheral side of the rotor 3 (outward in the radial direction of the motor 1). Further, the stator core 21 of the stator 2 is arranged so that the teeth of the stator core 21 face the permanent magnet portion 31 of the rotor 3 in the radial direction of the stator 2. In other words, the stator 2 is arranged so that the annular permanent magnet portion 31 of the rotor 3 faces the stator core 21 of the stator 2 in the radial direction.

[0029] The motor housing 10 may have any shape. For example, the motor housing 10 may be formed into a hollow cylindrical shape having an open end surface on one side (in this embodiment, the output opposite side of the shaft 32) in the axial direction of the central axis of the motor 1 (i.e., the rotation axis of the rotor 3 (hereinafter, the rotation axis C)). In this embodiment, the motor housing 10 includes an annular portion 12 and an end surface portion 13 formed at an end of the annular portion 12 on the opposite side to the opening. The end surface portion 13 expands inwardly from the annular portion in the radial direction (inner diameter direction).

[0030] The rotor 3 is rotatably arranged on the inner circumference side of the stator core 21 of the stator 2 with a predetermined gap (clearance) between the stator core 21 and the rotor 3. Figure 2 , Figure 4 and Figure 5 As shown, the permanent magnet portion 31 is annularly arranged on the outer side (outer peripheral side) in the radial direction of the rotor 3 so as to face the stator core 21 .

[0031] 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 received (held) in a first bearing receiving portion 42 (bearing seat portion) described later, and the second bearing 34 is received (held) in a second bearing receiving portion 43 (bearing seat portion) described later, so that the rotor 3 is rotatably supported. The first bearing receiving portion 42 and the second bearing receiving portion 43 are formed of a magnetic substance such as chromium-nickel-based stainless steel.

[0032] <Bearings, brackets and bearing housings>

[0033] like Figure 2 , Figure 4 and Figure 5 As shown, the first bearing 33 is fixed to one end side (the 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 (the 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 (pivotally support) the shaft 32 and the rotor 3 fixed to the shaft 32. For example, a ball bearing is used for each of the first bearing 33 and the second bearing 34.

[0034] The bracket 41 includes a first bearing receiving portion 42 formed of a magnetic material and receiving the first bearing 33, and a non-magnetic portion 44 (end surface portion) formed of a non-magnetic material (e.g., resin). In the motor housing 10 of the electric motor 1, the bracket 41 is arranged 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 44 (end surface portion) of the bracket 41 includes a connecting portion 45 (see FIG. 1 ) connected to the first bearing receiving portion 42. Figure 2 , Figure 3 and Figure 5 The non-magnetic portion 44 of the bracket 41 is formed integrally with the first bearing receiving portion 42 as a magnetic portion by insert molding. The non-magnetic portion 44 (end surface portion) is connected to the first bearing receiving portion 42 (bearing seat portion) at the connecting portion 45 .

[0035] The bracket 41 is attached to the end of the motor housing 10 on the opposite side of the output by using a screw to serve as a cover covering the opening of the motor housing 10 (main body). Note that the opening of the motor housing 10 may be set toward the output side. In this case, the bracket 41 is not arranged on the opposite side of the output of the shaft 32, but is arranged on the output side of the shaft 32.

[0036] The non-magnetic portion 44 (end surface portion) of the bracket 41 is formed into a substantially circular plate shape having a radial profile, which extends radially to the outer peripheral surface of the motor housing 10. The non-magnetic portion 44 of the bracket 41 forms a resin housing of the motor 1 together with the motor housing 10. In addition, the non-magnetic portion 44 includes a protrusion 410 that protrudes 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 protection portion 102 of the motor housing 10. The protection portion 102 will be described later.

[0037] The protrusions 410 provided to the bracket 41 are formed as many (three positions) as the protection portion 102 provided to the motor housing 10. For example, when viewed from the direction of the rotation axis C, the protrusions 410 are each formed into a trapezoidal shape, and each includes a screw through hole 413 penetrating in the direction of the rotation axis C at its center portion.

[0038] Note that the bracket 41 includes a slit groove 416 in the outer surface exposed to the outside in the assembled motor 1, which is used to provide the conductive member 5 for anti-electrolytic corrosion measures, which will be described later (see Figure 1 and Figure 3 ).

[0039] The slit groove 416 extends radially outward from a central portion of the bracket 41 (a tubular connecting portion 45 of the nonmagnetic portion 44 described later) to an outer peripheral surface of the bracket 41 , and further extends axially therefrom to a position abutting against the motor housing 10 .

[0040] The bracket 41 is assembled into the motor housing 10 and then fixed to the screw holes 103 (described later) of the protection portion 102 of the motor housing 10 by screws via the screw through holes 413 (see Figure 1 ).

[0041] Further, a first bearing receiving portion (bearing seat portion) 42 for receiving the first bearing 33 on the inner side (opposite to the output side) of the motor 1 is arranged at the center of the disc-shaped bracket 41. The first bearing receiving portion 42 is formed into a substantially bottomed cylindrical shape by press working, for example.

[0042] A second bearing receiving portion (bearing seat portion) 43 for receiving 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 portion of the motor housing 10. The second bearing receiving portion 43 is formed into, for example, a substantially bottomed cylindrical shape similar to the first bearing receiving portion 42. The second bearing receiving portion 43 is arranged radially inward (inner diameter side) of the rotor 3 relative to the annular permanent magnet portion 31.

[0043] The end surface portion 13 of the motor housing 10 includes a connecting portion 14 connected to a flange portion 432 (described later) of the second bearing receiving portion 43 .

[0044] like Figure 2 and Figure 5 As shown, the first bearing receiving portion 42 as one of a pair of bearing seat portions includes: a tubular portion 421, which radially holds the outer ring side of the first bearing 33; an annular flange portion 422, which extends radially outward 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, which extends radially inward 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) of the rotor 3 relative to the permanent magnet portion 31. In other words, the first bearing receiving portion 42 is formed so as not to overlap with the permanent magnet portion 31 when viewed from the direction of the rotation axis C of the rotor 3.

[0045] Specifically, when viewed from the direction of the rotation axis C, the first bearing receiving portion 42 (bearing seat portion) is arranged radially inward (inner diameter side) of the rotor 3 relative to the permanent magnet portion 31. Further, the outer peripheral edge portion of the flange portion 422 of the first bearing receiving portion 42 (the edge portion of the first bearing receiving portion 42 on the outer diameter side) 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 receiving portion 42 is covered with a non-magnetic portion 44 made of resin.

[0046] As described above, the bracket 41 is formed by the first bearing receiving portion (magnetic portion) 42 as one of a pair of bearing receiving portions (bearing seat portion) and the non-magnetic portion 44 (end surface portion). The first bearing receiving portion (magnetic portion) 42 is arranged on the inner diameter side relative to the permanent magnet portion 31 in the radial direction of the rotor 3, thereby preventing the flange portion 422 of the first bearing receiving portion 42 serving as the magnetic portion from facing the permanent magnet portion 31 in the direction of the rotation axis C.

[0047] This makes it possible to suppress the leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing receiving portion (magnetic portion, bearing seat portion) 42. In addition, in the first bearing receiving portion 42, the outer peripheral edge portion of the flange portion 422 arranged close to the permanent magnet portion 31 of the rotor 3 is covered by 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 receiving portion (magnetic portion, bearing seat portion) 42 formed by a magnetic material by the non-magnetic portion (end surface portion) 44 formed by a non-magnetic material, thereby further suppressing the leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing receiving portion 42.

[0048] 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 radially 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 relative to the permanent magnet portion 31.

[0049] Furthermore, the outer peripheral edge portion of the flange portion 432 of the second bearing receiving portion 43 is covered by the end surface portion 13 (connecting portion 14) of the motor housing 10 which is a resin of a non-magnetic material. This makes it possible to suppress the leakage flux flowing from the permanent magnet portion 31 to the second bearing receiving portion 43. The structure for suppressing such leakage flux can be applied to either or both of the first bearing receiving portion 42 and the second bearing receiving portion 43 which are a pair of bearing seat portions.

[0050] The non-magnetic portion (end face portion) 44 of the bracket 41 includes a connection portion 45 connected to the first bearing receiving portion (bearing seat portion) 42. The connection portion 45 is formed in a substantially tubular shape, and a flange portion 422 of the bearing seat portion (first bearing receiving portion 42) formed of a magnetic material 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 receiving portion 42 is not in contact with the non-magnetic portion 44 of the bracket 41 (not covered by the non-magnetic portion 44), and only the outer peripheral edge portion of the flange portion 422 is linked (connected) to the connection portion 45 of the non-magnetic portion (end face 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 receiving portion 42 (bearing seat portion) and the tubular connection portion 45 of the non-magnetic portion (end face portion) 44 forming the resin housing.

[0051] With this configuration, deformation of the resin housing (motor housing 10, end surface portion (non-magnetic portion) 44) due to heat, impact, etc. hardly affects the first bearing 33. Furthermore, the contact area between the connection portion 45 of the bracket 41 and the flange portion 422 of the first bearing receiving portion 42 can be reduced, thereby preventing heat generated at the winding wound in the stator core 21 from being transferred to the first bearing 33 via the bracket 41. This makes it possible to suppress a temperature increase in the first bearing 33 and prevent the first bearing 33 from being deteriorated.

[0052] Here, with respect to the first bearing receiving portion 42 side (the output opposite side) (the first bearing receiving portion 42 is one of a pair of bearing receiving portions), the annular portion 12 of the motor housing 10 which is integral with the stator 2, and the end face portion (resin non-magnetic portion 44 of the bracket 41) which is connected to the end of the annular portion 12 and expands radially inward (inner peripheral side) are separately formed to serve as a resin housing for the motor 1. However, the annular portion 12 and the end face portion in the resin housing may be formed integrally. In the present embodiment, on the second bearing receiving portion 43 side (the second bearing receiving portion 43 is the other of a pair of bearing receiving portions), the annular portion 12 and the end face portion are integrally formed into a resin housing.

[0053] Specifically, on the side (output side) of the second bearing receiving portion 43 (the second bearing receiving portion 43 is the other of a pair of bearing receiving portions), the second bearing receiving portion 43 is formed into a shape similar to the first bearing receiving portion 42. Note that the structures of the first bearing receiving portion 42 and the second bearing receiving portion 43 may be the same, and the first bearing receiving portion 42 and the second bearing receiving portion 43 may be arranged inverted to share their constituent parts. The motor housing 10 is formed into a substantially bottomed cylindrical shape, and includes: an annular portion 12 of the motor housing 10, which is integral 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 in the direction of the rotation axis C and expands 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 receiving portion 43. In addition, similar to the first bearing receiving portion 42, the second bearing receiving portion 43 also includes 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 side surface on the inner diameter side 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 receiving portion 43 and the connecting portion 14 of the resin housing (motor housing 10).

[0054] With this configuration, deformation of the resin case (the annular portion 12 and the end surface portion 13 of the motor case 10) due to heat, impact, etc. hardly affects the second bearing 34. Furthermore, the contact area between the connection portion 14 of the motor case 10 and the flange portion 432 of the second bearing receiving portion 43 can be reduced, thereby preventing the heat generated at the winding wound in the stator core 21 from being transferred to the second bearing 34 via the resin case. This makes it possible to suppress the temperature increase of the second bearing 34 and prevent the second bearing 34 from being deteriorated.

[0055] As described above, the rotor 3 includes the 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 in the radial direction. The coupling portion 35 is arranged on the inner diameter side of the annularly arranged permanent magnet portion 31. Figure 2 and Figure 4 As shown, the coupling portion 35 includes an annular recess 36 that is recessed in the axial direction of the rotation axis C (in the direction of the rotation axis C). The recess 36 is formed so 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 receiving portion 42 is arranged to overlap with the recess 36 formed in the coupling portion 35 in the direction of the rotation axis C. This makes it possible to form an annular recess 36 recessed toward the direction of the rotation axis C on the rotor 3, so that the flange portion 422 of the first bearing receiving portion 42 can be arranged in the recess 36.

[0056] In this way, a portion of the first bearing receiving portion 42 (flange portion 422) enters the annular recess 36 recessed in the axial direction of the rotation axis C (in the direction of the rotation axis C), thereby reducing the thickness of the motor 1 in the direction of the rotation axis C and reducing the size of the motor 1 along the direction of the rotation axis C.

[0057] like Figure 4 As shown, at the end of the stator 2 on the opposite side of the output in the direction of the rotation axis C ( Figure 4 The upper end portion in the middle is provided with terminal pins 26 electrically connected to the winding (not shown) of the stator core 21, and bosses 27 each serving as a guide member used when attaching a base plate (not shown).

[0058] The bracket 41 functions as an insulating cover for preventing the terminal pins 26 from being exposed to the outside of the motor 1. In the present embodiment, the terminal pins 26 are provided at three locations, and the bracket 41 is attached to the motor case 10 so as to cover the three locations.

[0059] The bracket 41 includes a cover body 414 attached along the upper end surface of the stator 2 and a fitting portion 415 formed integrally with the cover body 414. The cover body 414 and the fitting portion 415 correspond to the non-magnetic portion 44 (end surface portion).

[0060] The cover body 414 is formed as a whole in a substantially circular plate shape. Figure 3 As shown, the fitting portion 415 is formed as an annular protrusion arranged at the outer peripheral edge portion of the cover body 414. The fitting portion 415 is fitted to the motor housing 10 on the opposite side of the output ( Figure 4 The motor housing 10 (main body) is positioned at the end of the bracket 41 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 receiving portion 42 provided to the bracket 41, as shown in FIG. Figure 2 shown.

[0061] The motor housing 10 includes three protection portions 102 arranged at regular intervals in the circumferential direction at the end of the rotation axis C on the opposite side of the output. Note that any number of protection portions 102, such as two or six protection portions 102, may be provided, and the plurality of protection portions 102 do not have to be arranged at regular intervals. Each of the three protection portions 102 protrudes in a trapezoidal shape in the radial direction of the stator 2 (motor 1), and each has a predetermined thickness in the direction of the rotation axis C.

[0062] like Figure 1 and Figure 4 As shown, each protection part 102 includes a cutout portion 104 for fitting the vibration-proof rubber bushing 6, which is formed from the radially outer side toward the radially inner side of the stator 2 (motor 1). The cutout portion 104 is formed to connect a hole formed in each protection part 102 to penetrate in the direction of the rotation axis C and the outer peripheral edge of the protection part 102 to each other. In addition, each protection part 102 includes a screw hole 103 through which the above-mentioned bracket 41 is fixed with a screw.

[0063] The lower surface (the surface on the output side) of each protection portion 102 includes a recessed portion 106 formed to easily hold the vibration-proof rubber bush 6 (see Figure 1 and Figure 4 ).

[0064] like Figure 4 As shown, any one of the three protection parts 102 includes a conductive member 5 for arranging anti-electrolytic corrosion measures along the rotation axis C direction (see Figure 5 ) is formed at the innermost diameter side of the cutout portion 104 in the radial direction of the stator 2 (motor 1). Along the slit groove 105, slit grooves for the conductive member 5 are also formed on the side surface and the end surface portion 13 (the surface on the output side) of the motor housing 10 so as to extend in the axial direction and radial direction (not shown) of the rotation axis C.

[0065] The conductive member 5 is a bar-shaped member for conducting electricity between the first bearing 33 and the second bearing 34. The conductive member 5 is formed, for example, by punching a steel plate into a bar shape and bending the obtained steel plate into a substantially U shape (square U shape). The conductive member 5 is arranged along the outer surfaces of the motor housing 10 and the bracket 41 (see Figure 5 ). The conductive member 5 allows the first bearing 33 and the second bearing 34 to have the same potential on the outer ring side, thereby suppressing the occurrence of electrolytic corrosion on the bearings.

[0066] Here, when the bracket 41 is assembled into the motor housing 10, the slit groove 416 of the bracket 41 and the slit groove 105 formed in the outer surface of the motor housing 10 become continuous, and both slit grooves become guides into which the strip-shaped conductive member 5 will be embedded. This makes it possible to prevent the strip-shaped conductive member 5 from protruding from the surface of the housing of the permanent magnet motor 1 and falling off. Figure 5 As shown, the conductive member 5 is arranged to extend from the position of the flange portion 422 of the first bearing receiving portion 42 to the position of the flange portion 432 of the second bearing receiving portion 43 through the slit groove 416 of the bracket 41, the slit groove 105 of the protective portion 102 and the slit groove (not shown) of the outer surface of the motor housing 10.

[0067] As described above, in the motor 1, two bearings, the first bearing 33 and the second bearing 34, are arranged, and two bearing seats, the first bearing receiving portion 42 and the second bearing receiving portion 43, are arranged. The bearing seats 42 and 43 receive the bearings 33 and 34, respectively. Further, the motor 1 includes a conductive member 5 for conducting electricity between the two bearings 33 and 34. In addition, at least one end portion (in the present embodiment, both ends) of the conductive member 5 is arranged in the gap portions AG1 and AG2 formed between the tubular portions 421 and 431 of the bearing seats 42 and 43 and the connection portions 45 and 14 of the resin housing (end surface portions 44 and 13) (see Figure 5 ). With this structure, the end of the conductive member 5 for preventing electrolytic corrosion is arranged in the gap portions AG1, AG2 that become the tubular gap, thereby preventing the conductive member 5 from falling off when the end of the conductive member 5 is touched by hand and the conduction between the bearings is hindered. Furthermore, the end of the conductive member 5 can be press-fitted into the above-mentioned gap portions AG1, AG2 to be easily fixed to the outer peripheral surface of the bearing seat portions 42, 43.

[0068] Further, before the vibration-proof rubber bushing 6 is assembled to the protection portion 102 , the conductive member 5 is inserted into the slit groove 105 in advance, so that the vibration-proof rubber bushing 6 can press the conductive member 5 from the outside and can prevent the conductive member 5 from falling off.

[0069] As described above, in the present embodiment, since the resin case (motor case 10, non-magnetic portion 44) having a large deformation amount due to heat does not cover the entire bearing seat portions 42 and 43, deformation of the first bearing 33 and the second bearing 34 and the bearing seat portions 42 and 43 accompanying deformation of the resin case can be suppressed. Further, heat generated at the winding wound in the stator core 21 can be prevented from being transferred to the bearings 33 and 34 via the resin case.

[0070] At the same time, the resin case (connection portion 14 of motor case 10, connection portion 45 of bracket 41) is connected to the outer edges of flange portions 422, 432 of bearing housing portions 42, 43 so that bearing housing portions 42, 43 can be fixed to the resin case.

[0071] Furthermore, a pair of bearings (first bearing 33 and second bearing 34) and a pair of bearing seats (first bearing housing 42 and second bearing housing 43) can be prevented from protruding in the axial direction of the rotation axis C, and the size of the motor 1 can be reduced in the direction of the rotation axis.

[0072] Reference numerals list

[0073] 1 Electric motor

[0074] 10 Motor housing (resin housing)

[0075] 12 Ring

[0076] 13 End face

[0077] 14Connection

[0078] 2 Stator

[0079] 21 stator core

[0080] 3 rotors

[0081] 31Permanent Magnet Department

[0082] 32 Axis

[0083] 33 First bearing

[0084] 34 Second bearing

[0085] 35 connection part

[0086] 36 recesses

[0087] 41 Bracket

[0088] 42, 43 bearing receiving portion (bearing seat portion)

[0089] 421, 431 Tubular part

[0090] 422, 432 flange part

[0091] 423, 433 crown

[0092] 44 End surface (non-magnetic part)

[0093] 45 connection part

[0094] 5. Conductive components

[0095] AG1, AG2 gap

[0096] C Rotation axis

Claims

1. An electric motor, comprising: Cylindrical rotor; a shaft disposed along an axis of rotation of the rotor; a cylindrical stator core arranged on the outer peripheral side of the rotor; A resin shell covering the stator core; a bearing rotatably supporting the shaft; and a bearing seat portion, the bearing seat portion accommodating the bearing, in, The resin housing includes: an annular portion, the annular portion being integrated with the stator core; and an end surface portion, the end surface portion being connected to an end portion of the annular portion and extending from the annular portion toward an inner peripheral side, The end surface portion includes a connection portion connected to the bearing seat portion, The bearing housing portion includes a tubular portion and a flange portion extending from an end of the tubular portion to the outer peripheral side, and The outer peripheral edge portion of the flange portion is fixed to the connecting portion of the resin case, The tubular portion of the bearing housing and the connecting portion of the resin housing form a gap therebetween. Arranging two of the bearings and two of the bearing seats, The motor further includes a conductive member for conducting electricity between the two bearings, and At least one end portion of the conductive member is arranged in the slit portion.

2. The electric motor according to claim 1, wherein The connection portion of the resin housing is formed in a tubular shape extending protrudingly from an end portion on the inner peripheral side of the end surface portion toward the center in the axial direction of the rotation axis, and The flange portion of the bearing seat portion is inserted into and fixed to a side surface of the connecting portion on an inner diameter side.

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