permanent magnet motor

Abstract

A permanent magnet motor is provided that can be reduced in size in the direction of the rotation axis and that can suppress leakage magnetic flux. The permanent magnet motor includes: a cylindrical rotor including an annularly arranged permanent magnet portion; a shaft arranged along the rotor's rotation axis; a cylindrical stator core arranged on the outer circumference of the rotor; a main body including a housing integrally formed with the stator core; a bracket attached to one end of the main body; and a bearing that rotatably supports the shaft. The bracket includes a bearing seat portion that accommodates the bearing and a non-magnetic portion connected to the bearing seat portion. When viewed axially from the rotation axis, the bearing seat portion is arranged on the inner diameter side relative to the permanent magnet portion, and the edge portion of the bearing seat portion on the outer diameter side is covered by the non-magnetic portion.

Description

Technical Field

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

[0002] As an electric motor, there is conventionally known an inner rotor permanent magnet motor in which a cylindrical rotor including a permanent magnet portion is arranged coaxially with a cylindrical stator that generates a rotating magnetic field and on the inner diameter side of the cylindrical stator.

[0003] This type of permanent magnet motor includes a rotor including an annular permanent magnet portion radially facing the stator, and a coupling portion (yoke) coupling the permanent magnet portion to a shaft. In the permanent magnet motor of Patent Document 1, a bearing housing portion (bearing bracket) that holds a bearing is arranged near the rotor in the axial direction of the stator, allowing the motor to be reduced in size in the axial direction.

[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] However, there is the following problem: if a bearing seat portion (bearing bracket) formed of a magnetic material is arranged near the permanent magnet portion of the rotor, the magnetic flux flowing from the permanent magnet portion of the rotor to the yoke (connecting portion) side of the stator also flows to the bearing seat side, and the leakage magnetic flux increases, which reduces the output of the permanent magnet motor.

[0009] Beneficial effects of the present invention

[0010] In this regard, an object of the present invention is to provide a permanent magnet motor that can be downsized in the axial direction and can suppress leakage magnetic flux.

[0011] Technical Solution

[0012] According to one aspect of the present invention, a permanent magnet motor is provided, comprising: a cylindrical rotor including permanent magnet portions arranged in an annular manner; a shaft arranged along the rotation axis of the rotor; a cylindrical stator core arranged on the outer peripheral side of the rotor; a main body including a shell formed integrally with the stator core; a bracket attached to one end side of the main body; and a bearing rotatably supporting the shaft.

[0013] The bracket includes a bearing seat portion for accommodating the bearing and a non-magnetic portion connected to the bearing seat portion.

[0014] The bearing seat portion is arranged on the inner diameter side relative to the permanent magnet portion when viewed from the axial direction of the rotation axis.

[0015] An edge portion of the bearing seat portion on the outer diameter side is covered with the non-magnetic portion.

[0016] According to the present invention, the size of the electric motor can be reduced in the axial direction of the rotation axis, and leakage magnetic flux flowing from the permanent magnet portion of the rotor to the bearing seat portion can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an overall perspective view of the permanent magnet motor according to the present invention.

[0018] Figure 2 is a transverse sectional view of a permanent magnet motor according to the present invention.

[0019] Figure 3 It is a perspective view of a bracket of a permanent magnet motor according to the present invention.

[0020] Figure 4 is an overall perspective view of the permanent magnet motor according to the present invention, showing Figure 3 The bracket is removed.

[0021] Figure 5 It is along Figure 1 A cross-sectional view of a cross section taken through the slit groove is shown. DETAILED DESCRIPTION

[0022] Next, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the drawings, identical or similar parts will be represented by identical or similar reference numerals. It should be noted that the drawings are schematic and may differ from actual components. Therefore, specific components should be identified with reference to the following description.

[0023] Furthermore, the embodiments described below illustrate devices and methods for specifically implementing the technical concept of the present invention, and the technical concept of the present invention does not specify the shapes, structures, arrangements, etc. of the constituent parts to be the shapes, structures, arrangements, 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 claims.

[0024] Hereinafter, a motor according to an embodiment of the present invention will be described.

[0025] <Overall structure of the motor>

[0026] Figures 1 to 5The figures are used to describe the structure of a permanent magnet motor 1 of this embodiment. As shown in these figures, the permanent magnet motor 1 is, for example, a brushless DC motor. Although not shown in the figures, the permanent magnet motor 1 is used to rotationally drive a blower installed in an outdoor unit of an air conditioner, for example.

[0027] like Figure 1 and Figure 2 As shown, the permanent magnet motor 1 of this embodiment includes a stator 2 , a rotor 3 , a motor housing (shell, body) 10 and a bracket 41 .

[0028] 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 of a cylindrical stator 2 that generates a rotating magnetic field.

[0029] <Rotor, stator and motor housing>

[0030] 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 this 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 functions as a ferrite bonded magnet. Furthermore, the permanent magnet portion 31 is magnetized into a polar anisotropic magnet in which south poles and north poles appear alternately along its circumference. As a result, a portion of the yoke for concentrating the magnetic flux flow of the permanent magnet portion 31 becomes unnecessary, and leakage flux can be suppressed.

[0031] 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-mounted 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).

[0032] 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 toward the inner diameter side; and a winding (not shown) wound around the teeth via an insulator. The stator 2 is covered with a motor housing 10 (main body) formed of resin by integral resin molding except for the inner peripheral surface of the stator core 21 (see 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 2As shown, the stator 2 is arranged on the outer peripheral side of the rotor 3 (outward in the radial direction of the permanent magnet motor 1). Furthermore, 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. 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.

[0033] The motor housing 10 can have any shape. For example, the motor housing 10 can be formed into a hollow cylindrical shape having an open end surface on one side (in this embodiment, the side opposite the output 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 this embodiment, the motor housing 10 includes an annular portion 12 and an end surface portion 13 formed at the end of the annular portion 12 on the side opposite the opening.

[0034] The rotor 3 is rotatably arranged on the inner peripheral side of the stator core 21 of the stator 2 with a predetermined gap (clearance) between the rotor 3 and the stator core 21. Figure 2 、 Figure 4 and Figure 5 As shown, the permanent magnet portion 31 formed in a ring shape is arranged on the outer side (outer peripheral side) in the radial direction of the rotor 3 so as to face the stator core 21 .

[0035] 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 circumference of the shaft 32. Furthermore, the first bearing 33 is housed (held) in a first bearing receiving portion 42 (bearing seat portion) described later, and the second bearing 34 is housed (held) in a second bearing receiving portion 43 described later, thereby rotatably supporting the rotor 3. The first bearing receiving portion 42 and the second bearing receiving portion 43 are formed of a magnetic material, such as chromium-nickel-based stainless steel.

[0036] <Bearings, brackets, and housings>

[0037] like Figure 2 、 Figure 4 and Figure 5 As shown, the first bearing 33 is fixed to one end side (the opposite output 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 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.

[0038] 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 (main body) of the permanent magnet motor 1, the bracket 41 is arranged at one end in the direction of the rotation axis C, that is, on the opposite side of the output of the shaft 32. The non-magnetic portion 44 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, which is the magnetic portion, by insert molding. The non-magnetic portion 44 is connected to the first bearing receiving portion 42 (bearing seat portion) at the connecting portion 45. The bracket 41 is attached to the end of the motor housing 10 (main body) on the opposite side of the output by using screws to serve as a cover for covering the opening of the motor housing 10 (main body). Note that the opening of the motor housing 10 can 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.

[0039] The non-magnetic portion 44 (end surface portion) of the bracket 41 is formed into a generally circular plate shape with a radial profile, extending radially to the outer peripheral surface of the motor housing 10. The non-magnetic portion 44 of the bracket 41, together with the motor housing 10, forms the resin housing of the permanent magnet motor 1. Furthermore, the non-magnetic portion 44 includes protrusions 410 that protrude radially outward relative to the outer peripheral surface of the motor housing 10 when viewed from the direction of the rotation axis C. Each of the protrusions 410 abuts against the base end of the protective portion 102 of the motor housing 10. The protective portion 102 will be described later.

[0040] The bracket 41 has as many protrusions 410 (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 in a trapezoidal shape and each include a screw through hole 413 penetrating in the direction of the rotation axis C at its center portion.

[0041] Note that the bracket 41 includes a slit groove 416 in the outer surface exposed to the outside in the assembled permanent magnet 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 ).

[0042] The slit groove 416 extends radially outward from a central portion of the bracket 41 (a tubular connecting portion 45 of the non-magnetic portion 44 described later) to the outer peripheral surface of the bracket 41 and further extends axially therefrom to a position abutting against the motor housing 10 .

[0043] The bracket 41 is assembled into the motor housing 10 (main body) and then fixed to the screw holes 103 (described later) of the protection portion 102 of the motor housing 10 via the screw through holes 413 (see FIG. Figure 1 ).

[0044] Furthermore, 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 permanent magnet motor 1 is arranged at the center of the disc-shaped bracket 41. The first bearing receiving portion 42 is formed by stamping into, for example, a substantially bottomed cylindrical shape.

[0045] A second bearing receiving portion (bearing seat portion) 43 for accommodating the second bearing 34 on the inner side (output side) of the permanent magnet motor 1 is arranged in the center portion of the output-side end portion of the motor housing 10. Similar to the first bearing receiving portion 42, the second bearing receiving portion 43 is formed into, for example, a substantially cylindrical shape with a bottom. The second bearing receiving portion 43 is arranged radially inward (on the inner diameter side) of the rotor 3 relative to the annular permanent magnet portion 31. 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.

[0046] like Figure 2 and Figure 5 As shown, the first bearing receiving portion (bearing seat 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 from one end of the tubular portion 421 in the direction of the rotation axis C; and a crown portion 423 that 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 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 circumference) 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 in the direction of the rotation axis C of the rotor 3.

[0047] Specifically, when viewed from the direction of the rotation axis C, the first bearing receiving portion 42 (the bearing seat portion of the bracket 41) is arranged radially inward (diameter-inner) of the rotor 3 relative to the permanent magnet portion 31. Furthermore, the outer peripheral edge portion (diameter-outer edge portion) of the flange portion 422 of the first bearing receiving portion 42 (bearing seat portion) is covered with a resin, which is 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.

[0048] As described above, the bracket 41 is formed by a first bearing receiving portion (magnetic portion) 42, which is one of a pair of bearing receiving portions (bearing seat portions), and a 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. This prevents the flange portion 422 of the first bearing receiving portion 42, which serves as the magnetic portion, from facing the permanent magnet portion 31 in the direction of the rotation axis C. This makes it possible to suppress leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing receiving portion (magnetic portion) 42. In addition, in the first bearing receiving portion (magnetic portion) 42, the outer peripheral edge portion of the flange portion 422, which is 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 leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing receiving portion (bearing seat portion) 42 formed by magnetic material by the non-magnetic portion 44 formed by non-magnetic material, thereby further suppressing the leakage magnetic flux flowing from the permanent magnet portion 31 to the first bearing receiving portion 42.

[0049] Note that this structure for suppressing magnetic flux leakage applies not only to the first bearing housing 42 but also to the second bearing housing 43. The second bearing housing 43 has a similar shape to the first bearing housing 42 and includes a tubular portion 431 that radially holds the outer ring side of the second bearing 34; an annular flange 432 that extends radially outward from one end of the tubular portion 431 in the direction of the rotation axis C; and a crown 433 that extends radially inward from the other end of the tubular portion 431 in the direction of the rotation axis C. Furthermore, the second bearing housing 43 is positioned radially inward of the rotor 3 relative to the permanent magnet portion 31. Furthermore, the outer peripheral edge of the flange 432 of the second bearing housing 43 is covered by the end surface portion 13 (connecting portion 14) of the motor housing 10, which is a non-magnetic resin. This makes it possible to suppress leakage magnetic flux flowing from the permanent magnet portion 31 to the second bearing housing portion 43 .

[0050] The non-magnetic portion (end surface) 44 of the bracket 41 includes a connecting portion 45 connected to the first bearing receiving portion (bearing seat) 42. The connecting portion 45 is formed into a generally tubular shape, and the flange portion 422 of the first bearing receiving portion (bearing seat) 42 is inserted into and fixed to the inner diameter side of the tubular connecting portion 45. Here, the tubular portion 421 of the first bearing receiving portion 42 does not contact (is not covered by) the non-magnetic portion 44 of the bracket 41, and only the outer peripheral edge of the flange portion 422 is connected to (covered by) the connecting portion 45 of the non-magnetic portion 44. Furthermore, a gap (air gap) AG1 is formed between the tubular portion 421 of the first bearing receiving portion 42 and the tubular connecting portion 45 of the non-magnetic portion 44. With this configuration, deformation of the motor housing 10 due to heat, shock, etc., has little effect on 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 by 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 deterioration of the first bearing 33.

[0051] In this embodiment, the second bearing receiving portion 43, the other of the pair of bearing receiving portions, also has a structure similar to the first bearing receiving portion 42. Specifically, the motor housing 10 is formed into 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 surface portion 13 of the motor housing 10, which is connected to the end of the annular portion 12 and extends radially inward (inner circumferentially). Furthermore, the end surface portion 13 of the motor housing 10 includes a cylindrical connecting portion 14 connected to the second bearing receiving portion 43. Similarly to the first bearing receiving portion 42, the second bearing receiving portion 43, the other of the pair of bearing receiving portions, includes a tubular portion 431 and a flange portion 432 extending radially outward from the tubular portion 431. Only the outer peripheral edge of the flange portion 432 is inserted into and fixed to the inner diameter side surface of the connecting portion 14 of the resin housing (motor housing 10). Furthermore, a gap portion (air gap) AG2 is formed between the tubular portion 431 of the second bearing accommodating portion 43 and the connecting portion 14 of the resin housing (motor housing 10 ).

[0052] With this configuration, deformation of the motor housing 10 due to heat, impact, or the like hardly affects the second bearing 34. Furthermore, the contact area between the connection portion 14 of the motor housing 10 and the flange portion 432 of the second bearing receiving portion 43 can be reduced, thereby preventing heat generated by 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 a temperature increase in the second bearing 34 and prevent deterioration of the second bearing 34.

[0053] Furthermore, 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 a recessed portion 36 that is recessed toward the center of the coupling portion 35 in the axial direction of the rotation axis C (in the direction of the rotation axis C). The recessed portion 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 recessed portion 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 recessed portion 36 in the direction of the rotation axis C. This makes it possible to form the annular recessed portion 36 recessed in 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 within the recessed portion 36.

[0054] In this way, a portion of the first bearing receiving portion 42 (the flange portion 422 ) enters the annular recess 36 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 along the direction of the rotation axis C.

[0055] like Figure 4 As shown, at the end portion 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 FIG. 2 is provided with terminal pins 26 electrically connected to a winding (not shown) of the stator core 21, and bosses 27 each serving as a guide used when attaching a base plate (not shown).

[0056] The bracket 41 functions as an insulating cover for preventing the terminal pins 26 from being exposed to the outside of the permanent magnet 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.

[0057] 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).

[0058] The cover body 414 is formed in a circular plate shape as a whole. Figure 3 As shown, the fitting portion 415 is formed as an annular protrusion arranged on 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 4The motor housing 10 (main body) is positioned at the end thereof 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 of the bracket 41, as shown in FIG. Figure 2 shown.

[0059] The motor housing 10 includes three protective portions 102 arranged at regular intervals along the circumferential direction at the end portion of the rotation axis C on the opposite side of the output. Note that any number of protective portions 102, such as two or six, may be provided, and the plurality of protective portions 102 need not be arranged at regular intervals. Each of the three protective portions 102 projects in a trapezoidal shape in the radial direction of the stator 2 (permanent magnet motor 1) and has a predetermined thickness in the direction of the rotation axis C.

[0060] like Figure 1 and Figure 4 As shown, each protection portion 102 includes a cutout portion 104 for mounting the vibration-isolating rubber bushing 6. This cutout portion 104 is formed from the radially outer side toward the radially inner side of the stator 2 (permanent magnet motor 1). This cutout portion 104 is formed so as to connect a hole formed in each protection portion 102 so as to penetrate in the direction of the rotation axis C with the outer peripheral edge of the protection portion 102. In addition, each protection portion 102 includes a screw hole 103 through which the bracket 41 is fixed with a screw.

[0061] The lower surface (the surface on the output side) of each protection portion 102 includes a circular recess 106 formed to easily hold the vibration-proof rubber bush 6 (see FIG. Figure 1 and Figure 4 ).

[0062] like Figure 4 As shown, any one of the three protection parts 102 includes a conductive member 5 for arranging an anti-electrolytic corrosion measure along the rotation axis C direction (see Figure 5 ) is formed from the innermost diameter side of the cutout portion 104 in the radial direction of the stator 2 (permanent magnet motor 1) toward the rotation axis C. Along the slit slot 105, slit slots for the conductive member 5 are further formed on the side surface and the end surface portion 13 (the output-side surface) of the motor housing 10 so as to extend in the axial direction and radial direction (not shown) of the rotation axis C.

[0063] 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 square U shape 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.

[0064] 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 of the outer peripheral surface of the motor housing 10.

[0065] Further, before the vibration-isolating rubber bushing 6 is assembled to the protection portion 102 , the conductive member 5 is previously inserted into the slit groove 105 so that the vibration-isolating rubber bushing 6 can press the conductive member 5 from the outside and prevent the conductive member 5 from falling off.

[0066] As described above, in this embodiment, the bearing seat portions (first bearing receiving portion 42, second bearing receiving portion 43), each formed of a magnetic material, are arranged so as not to face the annular permanent magnet portion 31 in the direction of the rotation axis C. In addition, the outer peripheral edge portion of the flange portion 422 of the bearing seat portion 42 is covered with the non-magnetic portion 44 formed of a non-magnetic material so as to prevent the generation of a magnetic flux path that would short-circuit between the bearing seat portions 42 and 43 and the rotor 3 (permanent magnet portion 31) in the radial direction of the stator 2 (permanent magnet motor 1).

[0067] This makes it possible to suppress the generation of leakage magnetic flux by blocking the path of leakage magnetic flux flowing from the permanent magnet portion 31 to the bearing seats 42 and 43, even if the bearing seat portion 42 is arranged close to the permanent magnet portion 31 in the axial direction of the rotation axis C (in the direction of the rotation axis C). Furthermore, since the bearing seat portion 42 can be arranged close to the permanent magnet portion 31 in the axial direction of the rotation axis C (in the direction of the rotation axis C), the size of the permanent magnet motor 1 in the axial direction of the rotation axis C can be reduced.

[0068] Reference Signs List

[0069] 1Permanent magnet motor

[0070] 10 Motor housing (main body)

[0071] 12 ring part

[0072] 13 end face

[0073] 2 stator

[0074] 21 stator core

[0075] 3 rotors

[0076] 31 Permanent magnet part (magnetized part)

[0077] 32 axes

[0078] 33 first bearing

[0079] 34 Second bearing

[0080] 35 connection part

[0081] 36 recesses

[0082] 41 brackets

[0083] 42 first bearing receiving portion (bearing seat portion)

[0084] 421 tubular part

[0085] 422 flange

[0086] 423 crown

[0087] 43 second bearing receiving portion (bearing seat portion)

[0088] 44 non-magnetic portion (end surface)

[0089] 45 connection part

[0090] AG1, AG2 gap (air gap)

[0091] C Rotation axis

Claims

1. A permanent magnet motor, comprising: a cylindrical rotor including an annularly arranged permanent magnet portion; a shaft disposed along an axis of rotation of the rotor; a cylindrical stator core arranged on an outer peripheral side of the rotor; a main body, the main body comprising a shell formed integrally with the stator core; a bracket attached to one end side of the main body; and a first bearing and a second bearing, wherein the first bearing rotatably supports the shaft and is arranged on one end side of the main body, and the second bearing rotatably supports the shaft and is arranged on the other end side of the main body, wherein The bracket includes: a first bearing seat portion for accommodating the first bearing; and a non-magnetic portion connected to the first bearing seat portion, wherein the first bearing seat portion is a magnetic material. When viewed from the axial direction of the rotation axis, an edge portion of the first bearing seat portion on the outer diameter side is arranged on the inner diameter side relative to the permanent magnet portion, and the edge portion of the bearing seat portion on the outer diameter side is covered by the non-magnetic portion, The bracket further includes a second bearing seat portion for accommodating the second bearing, the second bearing seat portion being arranged on the other end side of the main body, and the second bearing seat being made of magnetic material. The main body includes an annular portion and an end portion, wherein the annular portion is integral with the stator core, and the end portion is made of a non-magnetic material, connected to the other end side of the annular portion and extending from the annular portion toward the inner circumference. The end surface portion includes a connection portion connected to the second bearing seat portion, When viewed from the axial direction of the rotation axis, an edge portion of the second bearing seat portion on the outer diameter side is arranged on the inner diameter side relative to the permanent magnet portion and is covered by the connecting portion.

2. The permanent magnet motor according to claim 1, wherein The first bearing seat portion includes a tubular portion and an annular flange portion extending radially outward from one end side of the tubular portion, and The outer edge of the flange portion is covered by the non-magnetic portion.

3. The permanent magnet motor according to claim 2, wherein: The permanent magnet portion of the rotor faces the stator core in the radial direction, The rotor further includes a coupling portion coupling the permanent magnet portion and the shaft to each other, The coupling portion includes an annular recessed portion that is arranged on the inner diameter side of the permanent magnet portion and is recessed toward the center of the coupling portion in the axial direction, and The flange portion of the first bearing seat portion is arranged to overlap with the recessed portion in the axial direction.

4. The permanent magnet motor according to claim 1, wherein: The permanent magnet portion is a bonded magnet.

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