Electric motors, fans and air conditioning devices

Abstract

The electric motor (100) comprises: a stator (5); an alternating pole rotor (1) having a rotating shaft (15); a bearing (21) which is a rolling bearing supporting the rotating shaft (15); a bearing retaining portion (6) fixed to the stator (5) and retaining an outer ring (21b) of the bearing (21); and a creep prevention portion (23). The creep prevention portion (23) is arranged between the outer ring (21b) and the bearing retaining portion (6) to increase the friction resistance of the outer ring (21b) in the circumferential direction between the outer ring (21b) and the bearing retaining portion (6).

Description

Technical Field

[0001] The present invention relates to a motor, a blower and an air conditioning device. Background Art

[0002] An electric motor having a stator and an alternating-pole rotor has been proposed. For example, refer to Patent Document 1. In the alternating-pole rotor, magnet poles and imaginary poles are formed on a rotor core.

[0003] The electric motor of Patent Document 1 further includes a bearing for supporting the rotating shaft of the rotor and a bearing holding portion for holding the bearing. Here, the outer ring of the bearing may be fixed to the bearing holding portion by a clearance fit.

[0004] Prior Art Literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-309953 (see, for example, paragraphs 0033, Figure 1 ) Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, when the outer ring is fixed to the bearing holder by a clearance fit, if a load is applied to the outer ring, creep may occur, in which the outer ring rotates while in contact with the bearing holder. If creep occurs, the contact surface between the outer ring and the bearing holder may wear, or vibration and noise of the bearing may increase.

[0009] As described in Patent Document 1, in an alternating-pole rotor, there is a case where the magnetic flux density in the magnet poles and the magnetic flux density in the virtual poles differ. At this time, since the magnitude of the magnetic attraction force acting between the rotor and the stator is not constant in the circumferential direction, there is a case where the rotor is eccentric and the exciting force acts on the outer ring. Therefore, in an electric motor with an alternating-pole rotor, a load that generates creep is likely to act on the outer ring of the bearing.

[0010] An object of the present disclosure is to prevent the occurrence of creep in a bearing in an electric motor having an alternating pole type rotor.

[0011] Solutions to Solve Problems

[0012] An electric motor in one form of the present disclosure comprises: a stator; an alternating-pole rotor having a rotating shaft; a bearing, which is a rolling bearing that supports the rotating shaft; a bearing retaining portion, which is fixed to the stator and retains the outer ring of the bearing; and a creep prevention portion, which is arranged between the outer ring of the bearing and the bearing retaining portion to increase the circumferential friction resistance of the outer ring between the outer ring of the bearing and the bearing retaining portion, and the friction coefficient between the creep prevention portion and the bearing retaining portion is greater than the friction coefficient between the outer ring and the bearing retaining portion.

[0013] Effects of the Invention

[0014] According to the present disclosure, in a motor having an alternating-pole type rotor, it is possible to prevent the occurrence of creep in a bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram showing a partial cross section and a side view of the electric motor according to the first embodiment.

[0016] Figure 2 Use A2-A2 line to Figure 1 The motor shown is a cross-sectional view obtained by cutting away.

[0017] Figure 3 It is shown Figure 2 An enlarged cross-sectional view of the structure of the rotor is shown.

[0018] Figure 4 This is a cross-sectional view showing the structure of a metal bracket of the electric motor according to the first embodiment.

[0019] Figure 5 This is a schematic diagram for explaining the creep of a bearing in an electric motor.

[0020] Figure 6 This is a magnetic flux diagram showing the simulation result of the flow of magnetic flux in the electric motor according to the first embodiment.

[0021] Figure 7 It is shown Figure 1 An enlarged cross-sectional view of the structure around the bearing on the load side of the motor shown.

[0022] Figure 8 (A) is shown Figure 7 (B) is a top view of the O-ring shown in (A), and (B) is a cross-sectional view of the O-ring shown in (A).

[0023] Fig. 9 This is an enlarged cross-sectional view showing the structure of the bearing and its surroundings on the load side of the electric motor according to the second embodiment.

[0024] Fig.10This is an enlarged cross-sectional view showing the structure of the bearing and its surroundings on the load side of the electric motor according to the third embodiment.

[0025] Fig.11 This is an enlarged cross-sectional view showing the structure of the bearing and its surroundings on the load side of the electric motor according to a modification of the third embodiment.

[0026] Fig.12 (A) is an enlarged cross-sectional view showing the structure around the bearing on the load side of the electric motor according to the fourth embodiment, and (B) is a partial front view showing the outer ring of the bearing on the load side shown in (A).

[0027] Fig.13 This is an enlarged cross-sectional view showing the structure of the bearing and its surroundings on the load side of the electric motor according to the fifth embodiment.

[0028] Fig.14 It is a structural diagram showing a partial cross section and side view of the electric motor according to the sixth embodiment.

[0029] Fig.15 It is a structural diagram showing a partial cross section and side surface of a motor according to a first modification of the sixth embodiment.

[0030] Fig.16 It is shown Fig.15 An enlarged cross-sectional view of the structure around the bearing on the opposite side of the load of the motor shown.

[0031] Fig.17 It is a structural diagram showing a partial cross section and side surface of a motor according to a second modification of the sixth embodiment.

[0032] Fig.18 It is a structural diagram showing a partial cross section and side surface of a motor according to a third modification of the sixth embodiment.

[0033] Fig.19 This is a diagram showing a configuration of an air conditioning apparatus to which the electric motor according to any one of Embodiments 1 to 6 is applied.

[0034] Fig. 20 It is shown Fig.19 A sectional view of the structure of the outdoor unit shown. DETAILED DESCRIPTION

[0035] Hereinafter, a motor, a blower, and an air conditioning device according to an embodiment of the present disclosure will be described with reference to the drawings. The following embodiments are merely examples, and the embodiments can be appropriately combined and each embodiment can be appropriately changed.

[0036] In order to make the explanation easier to understand, an xyz orthogonal coordinate system is shown in the accompanying drawings. The z axis is a coordinate axis parallel to the axis of the rotor. The x axis is a coordinate axis orthogonal to the z axis. The y axis is a coordinate axis orthogonal to both the x axis and the z axis.

[0037] Implementation Method 1

[0038] 〈Electric Motor〉

[0039] Figure 1 1 is a partial cross-sectional and side structural diagram of the motor 100 according to Embodiment 1. The motor 100 includes a rotor 1 and a molded stator 9 as a stator. The rotor 1 is arranged inside the molded stator 9. That is, the motor 100 is an inner rotor type motor.

[0040] The rotor 1 has a shaft 15 as a rotation axis. The rotor 1 can rotate around the axis C1 of the shaft 15. The shaft 15 protrudes from the molded stator 9 toward the +z axis side. A fan of a blower (i.e., an impeller 704 of an outdoor blower 150 described later) is mounted on the front end 15a of the shaft 15, for example. In the following description, the direction along the circumference of a circle centered on the axis C1 of the shaft 15 is referred to as the "circumferential direction" (e.g. Figure 2 The z-axis direction is referred to as the "axial direction", and the direction orthogonal to the axial direction is referred to as the "radial direction". The protruding side of the shaft 15 (i.e., the +z-axis side) is referred to as the "load side", and the opposite side of the shaft 15 relative to the load side is referred to as the "opposite load side".

[0041] The motor 100 further includes a bearing 21 supporting the load side of the shaft 15 and a bearing 22 supporting the opposite side of the load of the shaft 15. The bearing 21 and the bearing 22 are arranged on opposite sides of each other across the stator core 50 of the molded stator 9. The bearing 21 supports a portion 15c of the shaft 15 that is closer to the load side than the molded stator 9. The bearing 22 supports an end portion 15b of the shaft 15 on the -z axis side (i.e., the portion on the opposite side of the load) via an insulating sleeve 60. The bearing 21 and the bearing 22 are rolling bearings, such as ball bearings.

[0042] The insulating sleeve 60 is disposed between the end 15b on the -z axis side of the shaft 15 and the bearing 22. The insulating sleeve 60 is, for example, substantially cylindrical. The insulating sleeve 60 is, for example, formed of a thermosetting resin. In the first embodiment, the insulating sleeve 60 is formed of a BMC (Bulk Molding Compound) resin.

[0043] Since the insulating sleeve 60 is arranged between the end 15b on the -z axis side of the shaft 15 and the bearing 22, the shaft 15 and the bearing 22 are insulated. Therefore, the shaft current that causes electrolytic corrosion can be prevented from flowing from the shaft 15 to the bearing 22. In addition, by preventing the shaft current from flowing in the bearing 22, it is also possible to prevent the shaft current from flowing in the bearing 21 via the bearing 22, the molded stator 9, and the metal bracket 6. In addition, the insulating sleeve 60 can be arranged between the shaft 15 and the bearing 21, and can also be arranged between the shaft 15 and the bearing 21 and between the shaft 15 and the bearing 22.

[0044] like Figure 1 As shown, the motor 100 further includes a cover 8. The cover 8 is fixed to the shaft 15 so as to cover a part of the metal bracket 6. The cover 8 is a member for preventing foreign matter (such as water) from entering the inside of the motor 100.

[0045] 〈Modeling Stylus〉

[0046] Next, use Figure 1 and Figure 2 , the structure of the molded stator 9 is described. Figure 2 Use A2-A2 line to Figure 1 The rotor 1 and the molded stator 9 are cut into a cross-sectional view. Figure 2 In the figure, the mold resin portion 56 for molding the stator 9 is omitted from illustration.

[0047] like Figure 1 and Figure 2 As shown, the molded stator 9 includes a stator core 50 , a coil 55 wound around the stator core 50 , and a molded resin portion 56 covering the stator core 50 .

[0048] The stator core 50 includes an annular yoke 51 centered on the axis C1 and a plurality of teeth 52 extending radially inward from the yoke 51. The plurality of teeth 52 are arranged at regular intervals in the circumferential direction R1. The tip of each of the plurality of teeth 52 is radially opposed to the rotor 1 via an air gap. The coil 55 is wound around the teeth 52 via an insulator 53.

[0049] The molded resin portion 56 is formed of a thermosetting resin such as a BMC resin. The molded resin portion 56 has an opening 56a. The opening 56a is formed on the +z axis side of the molded resin portion 56. A metal bracket 6 as a bearing holding portion is fixed to the opening 56a. The metal bracket 6 holds the bearing 21 on the load side. That is, in the first embodiment, the bearing holding portion that holds the bearing 21 on the load side is formed of metal. In addition, as described later, Fig.17 or Fig.18 As shown, the bearing holding portion that holds the bearing 21 may also be formed of resin.

[0050] The molded resin portion 56 further includes a retaining portion 56b formed on the -z axis side. The retaining portion 56b retains the bearing 22. That is, in the first embodiment, the bearing retaining portion that retains the bearing 22 on the opposite side of the load is formed of resin. Figures 15 to 17 As shown, the bearing holding portion that holds the bearing 22 may also be formed of metal.

[0051] The circuit board 7 is embedded in the mold resin portion 56. The circuit board 7 is connected to a power lead wire for supplying electric power to the coil 55.

[0052] 〈Rotor〉

[0053] Next, use Figure 2 and Figure 3 , the structure of the rotor 1 is described. Figure 3 It is shown Figure 2 The enlarged cross-sectional view of the structure of the rotor 1 is shown. Figure 2 and Figure 3 As shown, the rotor 1 has a rotor core 10 and a shaft 15 .

[0054] The rotor core 10 is an annular member centered on the axis C1. The rotor core 10 is formed by fixing a plurality of electromagnetic steel plates stacked in the axial direction to each other by caulking, for example.

[0055] The rotor core 10 is provided with a permanent magnet 40. In the first embodiment, the permanent magnet 40 is embedded in the rotor core 10. That is, the rotor 1 has an IPM (Interior Permanent Magnet) structure. In addition, the rotor 1 may also have an SPM (Surface Permanent Magnet) structure in which the permanent magnet 40 is mounted on the outer periphery of the rotor core 10.

[0056] The rotor core 10 includes a first core portion 11 on which the permanent magnets 40 are mounted and a second core portion 12 on which the permanent magnets 40 are not mounted. In Embodiment 1, the rotor core 10 includes a plurality of (e.g., five) first core portions 11 and a plurality of (e.g., five) second core portions 12. The plurality of first core portions 11 and the plurality of second core portions 12 are alternately arranged along the circumferential direction R1.

[0057] The first core portion 11 has a magnet insertion hole 11a. The magnet insertion hole 11a is formed at a position radially inward of the outer periphery of the first core portion 11. The shape of the magnet insertion hole 11a is, for example, linear when viewed from above. In Embodiment 1, a permanent magnet 40 is inserted into one magnet insertion hole 11a. In addition, the shape of the magnet insertion hole 11a may be a V-shape that protrudes radially inward or radially outward when viewed from above. In addition, two or more permanent magnets 40 may be inserted into one magnet insertion hole 11a.

[0058] The permanent magnet 40 is, for example, a rare earth magnet. In the first embodiment, the permanent magnet 40 is, for example, a neodymium rare earth magnet containing Nd (neodymium) -Fe (iron) -B (boron).

[0059] like Figure 3 As shown in FIG. 1 , the plurality of permanent magnets 40 have magnetic poles (e.g., N poles) having the same polarity as each other on the radially outer side. Thus, a magnet pole P1 is formed on the outer periphery of the first core portion 11. In the following description, a straight line passing through the center (i.e., pole center) of the magnet pole P1 in the circumferential direction R1 and extending in the radial direction is referred to as a "pole center line M1" (see FIG. 1 ). Figure 6 ).

[0060] The plurality of permanent magnets 40 have magnetic poles (e.g., S poles) having the same polarity as each other on the radially inner side. Since the magnetic flux from the radially inner side of the permanent magnets 40 flows into the second core portion 12, an imaginary magnetic pole P2 (e.g., S pole) is formed on the radially outer side of the second core portion 12. Therefore, the plurality of second core portions 12 have imaginary magnetic poles P2 having the same polarity as each other on the radially outer side.

[0061] The rotor 1 is an alternating pole rotor in which magnet poles P1 and imaginary poles P2 are alternately arranged in the circumferential direction R1. In the alternating pole rotor 1, the number of permanent magnets 40 can be set to half compared to a non-alternating pole rotor with the same number of poles. Thus, the manufacturing cost of the rotor 1 can be reduced. In addition, in Embodiment 1, the number of poles of the rotor 1 is 10, but it is not limited to 10, as long as it is an even number greater than 2. In addition, in the rotor 1, the magnet pole P1 may be an S pole and the imaginary pole P2 may be an N pole.

[0062] The first core part 11 also has a plurality of magnetic flux isolation bridges 11b as leakage flux suppression holes. The magnetic flux isolation bridges 11b are formed on both sides of the magnet insertion hole 11a in the circumferential direction R1. Since the portion between the magnetic flux isolation bridges 11b and the outer periphery of the first core part 11 is thin-walled, the leakage flux between the adjacent magnet poles P1 and the imaginary poles P2 can be suppressed.

[0063] The second core portion 12 has a rivet portion 14. The rivet portion 14 is a rivet mark formed when a plurality of electromagnetic steel sheets stacked in the axial direction are fixed by rivet. In the first embodiment, the shape of the rivet portion 14 when viewed in the axial direction is, for example, circular. In addition, the shape of the rivet portion 14 is not limited to a circular shape, and may also be other shapes such as a rectangular shape.

[0064] The rotor 1 further includes a connection portion 30 connecting the rotor core 10 and the shaft 15. The connection portion 30 is formed of a resin material having electrical insulation properties. The connection portion 30 is formed of a thermoplastic resin such as PBT (Poly Butylene Terephthalate). The rotor core 10, the shaft 15, and the insulating sleeve 60 are integrated via the connection portion 30.

[0065] The connecting portion 30 includes an inner cylinder portion 31, a plurality of ribs 32, and an outer cylinder portion 33. The inner cylinder portion 31 is annular and contacts the outer peripheral surface 15d of the shaft 15. The outer cylinder portion 33 contacts the inner peripheral surface 10a of the rotor core 10. The plurality of ribs 32 connect the inner cylinder portion 31 and the outer cylinder portion 33. The plurality of ribs 32 extend radially outward from the inner cylinder portion 31. The plurality of ribs 32 are arranged at equal intervals in the circumferential direction R1 with the axis C1 as the center. A cavity portion 35 that passes through in the axial direction R1 is formed between the plurality of ribs 32 adjacent to each other in the circumferential direction R1. In addition, the rotor core 10 and the shaft 15 may be directly fixed without passing through the connecting portion 30.

[0066] like Figure 1 As shown, the rotor 1 further includes a sensor magnet 16. The sensor magnet 16 is installed, for example, at a position closer to the -z axis side than the rotor core 10 and faces the circuit board 7. The position of the rotor 1 in the circumferential direction R1 is detected by detecting the magnetic field of the sensor magnet 16 using a magnetic sensor (not shown) provided on the circuit board 7.

[0067] 〈Metal bracket〉

[0068] Next, use Figure 4 , the structure of the metal bracket 6 is described. Figure 4 2 is a cross-sectional view showing the structure of the metal bracket 6. The metal bracket 6 is formed of, for example, a galvanized steel plate. In addition, the metal bracket 6 is not limited to the galvanized steel plate, and may be formed of other metal materials such as aluminum alloy.

[0069] The metal bracket 6 has a cylindrical portion 61, a flange portion 62, a fixing portion 63, and a bottom portion 64. The cylindrical portion 61 extends substantially parallel to the axis C1. When the metal bracket 6 is fixed to the shaft 15, the cylindrical portion 61 and the outer ring 21b of the bearing 21 (see Figure 7) are radially opposed. The flange portion 62 is formed integrally with the cylindrical portion 61 and extends radially outward from the end of the cylindrical portion 61 on the opposite side of the load. The fixing portion 63 extends from the radially outer end of the flange portion 62 toward the +z axis side. The fixing portion 63 is fixed to the molded resin portion 56 (see Figure 1 The fixing portion 63 is fixed to the molded resin portion 56 by, for example, press-fitting.

[0070] The bottom portion 64 is formed integrally with the cylindrical portion 61 and extends radially inward from the load-side end of the cylindrical portion 61. The cylindrical portion 61, the flange portion 62, and the bottom portion 64 are formed, for example, by drawing the galvanized steel sheet. Figure 1 ) through which the shaft through-hole 65 passes. The shaft through-hole 65 protrudes from the radially inner end of the bottom surface portion 64 toward the +z axis side.

[0071] For example, in order to facilitate the assembly of the metal bracket 6 and the bearing 21, a metal bracket 61 is fixed to the cylindrical portion 61 in a clearance fit manner. Figure 1 The outer ring 21b of the bearing 21 is shown. When a load acts on the outer ring 21b while the motor 100 rotates while the outer ring 21b is fixed to the cylindrical portion 61 with a clearance fit, creep may occur in which the outer ring 21b rotates relative to the cylindrical portion 61.

[0072] Figure 5 2 is a schematic diagram for explaining creep in the bearing 21. Figure 5 As shown, the bearing 21 includes: an inner ring 21a, which supports the shaft 15; an outer ring 21b, which is fixed to the cylindrical portion 61 of the metal bracket 6 via a gap δ; and balls 21c as rolling elements, which are arranged between the inner ring 21a and the outer ring 21b. Figure 5 Although the gap δ is exaggerated in FIG. 1 , the size of the gap δ is approximately 10 μm. The circumferential length of the outer ring 21 b is shorter than the circumferential length of the cylindrical portion 61 .

[0073] Therefore, when the load Fr acts on the outer ring 21b during the rotation of the motor 100, creep occurs, in which the outer ring 21b rotates in the direction indicated by the arrow R2 while in contact with the cylindrical portion 61. When creep occurs, the fitting surface between the outer ring 21b and the cylindrical portion 61 wears, causing vibration and noise of the bearing 21, or causing wear powder to enter the inside of the bearing 21, etc.

[0074] The load Fr acting on the outer ring 21b is generated as a contact rotation radial load when the shaft 15 of the rotor 1 is eccentric, for example. Figure 6 As shown, due to the difference between the surface magnetic flux density in the magnet pole P1 and the surface magnetic flux density in the virtual pole P2, the shaft 15 of the rotor 1 is easily eccentric.

[0075] Figure 6 is a magnetic flux diagram showing the simulation result of the flow of magnetic flux in the motor 100. Figure 6 In order to make the description easier to understand, the permanent magnets are denoted by reference numerals 40a, 40b, 40c, 40d, and 40e.

[0076] like Figure 6 As shown in FIG. 1 , since the magnetic flux from the radially inner side of the permanent magnet 40a flows into the second core portion 12 located on both sides of the circumferential direction R1 with respect to the pole center line M1, a virtual magnetic pole P2 (see FIG. 1 ) is formed. Figure 3 ). However, if Figure 6 As shown, in the alternating pole rotor 1, a magnetic flux density deviation may occur between the second core portions 12 located on both sides of the circumferential direction R1 with respect to the pole center line M1. Therefore, in the circumferential direction R1 of the rotor 1, there is a case where the difference between the surface magnetic flux density at the magnet pole P1 and the surface magnetic flux density at the virtual pole P2 becomes large.

[0077] In this case, the magnitude of the magnetic attraction acting between the stator core 50 and the rotor 1 becomes unbalanced in the circumferential direction R1. Therefore, the axis C1 of the shaft 15 is eccentric and the radial exciting force acts on the rotor 1. Therefore, in the motor 100 of the first embodiment, the radial exciting force is Figure 5 The load Fr shown acts on the bearing 21 or the bearing 22 that supports the shaft 15 of the rotor 1 .

[0078] In addition, when the fan of the blower is mounted on the front end portion 15a of the shaft 15 (see Figure 1 ) the weight of the fan will also be Figure 5 The load Fr shown in FIG. 1 acts on the bearing 21. Therefore, the load Fr is larger in the bearing 21 than in the bearing 22, and creep is easily generated. Therefore, in the first embodiment, the creep prevention portion (in the first embodiment, the creep prevention portion) for preventing the occurrence of creep in the bearing 21 is Figure 1 or Figure 7 The annular elastic body 23) shown is described.

[0079] Figure 7 It is shown Figure 1FIG. 1 is an enlarged cross-sectional view of the structure around the bearing 21 of the motor 100. Figure 7 As shown, the motor 100 includes an annular elastic body 23 as an elastic member serving as a creep prevention portion. The annular elastic body 23 is disposed between the outer peripheral surface 21f of the outer ring 21b and the inner peripheral surface 61a of the cylindrical portion 61 and is compressed in the radial direction.

[0080] The friction coefficient between the annular elastic body 23 and the cylindrical portion 61 is greater than the friction coefficient between the outer ring 21b and the cylindrical portion 61. That is, since the annular elastic body 23 is provided between the outer ring 21b and the cylindrical portion 61, the friction resistance (i.e., friction force) in the circumferential direction R1 between the outer peripheral surface 21f of the outer ring 21b and the inner peripheral surface 61a of the cylindrical portion 61 is increased. As a result, since the outer ring 21b is difficult to rotate relative to the cylindrical portion 61, the occurrence of creep in the bearing 21 can be suppressed.

[0081] Figure 8 (A) is shown Figure 7 The top view of the annular elastic body 23 is shown, Figure 8 (B) is shown Figure 8 (A) is a cross-sectional view of the annular elastic body 23 shown. Figure 8 As shown in (A) and (B), the annular elastic body 23 is an elastic member having an annular shape with the axis C1 as the center. The cross-sectional shape of the annular elastic body 23 is, for example, a circle. In the first embodiment, the annular elastic body 23 is an O-ring. In addition, the cross-sectional shape of the annular elastic body 23 is not limited to a circle, and may be other shapes such as a quadrilateral.

[0082] When the annular elastic body 23 is an O-ring, the friction coefficient between the O-ring and the target surface is, for example, a value within the range of 1.03 to 1.25. Here, the friction coefficient between the iron constituting the outer ring 21b and the metal bracket 6 and the target surface is about 0.2. Therefore, the friction coefficient between the O-ring and the target surface is greater than the friction coefficient between the iron and the target surface.

[0083] The annular elastic body 23 is, for example, a rubber including a thermosetting elastomer. Examples of the rubber including a thermosetting elastomer include fluororubber, silicone rubber, ethylene-propylene rubber, nitrile rubber, and the like.

[0084] like Figure 7 As shown, the annular elastic body 23 is disposed in a groove 21d formed on the outer peripheral surface 21f of the outer ring 21b. The groove 21d is a long groove extending along the circumferential direction R1 on the outer peripheral surface 21f. Alternatively, the groove 21d may be formed on the inner peripheral surface 61a of the cylindrical portion 61.

[0085] Here, in the outer ring 21b, the axial central portion which overlaps the center of the ball 21c in the axial direction needs to have a wall thickness sufficient to bear the load from the ball 21c. Therefore, in the first embodiment, the groove 21d is formed on the outer peripheral surface 21f at a position which is axially directed to one side (at Figure 7 Thus, in the outer ring 21b, the wall thickness of the axial center portion can be ensured to be sufficient, and the annular elastic body 23 can be arranged on the outer ring 21b. In addition, the groove portion 21d can also be formed on the outer peripheral surface 21f at a position offset to the -z axis side with respect to the axial center position P of the ball 21c.

[0086] In addition, the annular elastic body 23 is arranged on the bottom face 64 side between the outer ring 21b and the cylindrical portion 61 with the axial center position P of the ball 21c as a reference. As described above, the cylindrical portion 61, the flange portion 62 and the bottom face 64 are formed by, for example, drawing a galvanized steel sheet. As the die (i.e., the punch) advances during the drawing process, the flange portion 62 side of the inner circumferential surface 61a of the cylindrical portion 61 is more likely to expand radially outward than the bottom face 64 side. That is, in the inner circumferential surface 61a of the cylindrical portion 61, the closer to the bottom face 64, the easier it is to obtain a higher dimensional accuracy. Therefore, by arranging the annular elastic body 23 on the bottom face 64 side between the outer ring 21b and the cylindrical portion 61 with the axial center position P of the ball 21c as a reference, the compressive force acting on the annular elastic body 23 can be stabilized. As a result, since the friction force that prevents the outer ring 21 b from rotating relative to the cylindrical portion 61 is stabilized, the occurrence of creep in the bearing 21 can be further prevented.

[0087] The motor 100 further includes a preload spring 45 disposed between the bottom surface 64 of the metal bracket 6 and the bearing 21. The preload spring 45 applies a force to push the end surface 21i of the outer ring 21b in the axial direction toward the Figure 1 The force of pressing the molded stator 9 shown in FIG. As a result, the internal clearance of the bearing 21 becomes a negative clearance, thereby improving the rigidity of the bearing 21. The preload spring 45 has a through hole 45a through which the shaft 15 passes. The preload spring 45 is, for example, a wave washer.

[0088] <Effects of Implementation Method 1>

[0089] According to the electric motor 100 of the first embodiment described above, the following effects can be obtained.

[0090] According to the motor 100 of the first embodiment, the annular elastic body 23 is provided to increase the friction resistance in the circumferential direction R1 between the outer peripheral surface 21f of the outer ring 21b of the bearing 21 and the inner peripheral surface 61a of the cylindrical portion 61 of the metal bracket 6. This can prevent the occurrence of creep in the bearing 21. Therefore, in the motor 100, it is possible to prevent the occurrence of vibration and noise caused by creep, and improve the quality of the motor 100.

[0091] In addition, according to the motor 100 of the first embodiment, the groove 21d for arranging the annular elastic body 23 is formed in the outer ring 21b at a position offset to one side in the axial direction with respect to the axial center position P of the ball 21c. Thus, in the outer ring 21b, the wall thickness of the axial center portion can be ensured to be sufficient, and the annular elastic body 23 can be arranged.

[0092] In addition, according to the motor 100 of the first embodiment, the annular elastic body 23 is arranged on the bottom surface 64 side between the outer ring 21b and the cylindrical portion 61 with the axial center position P of the ball 21c as a reference. In the case where the metal bracket 6 is formed by drawing, the closer to the bottom surface 64 the inner circumferential surface 61a of the cylindrical portion 61 is, the easier it is to obtain higher dimensional accuracy. Therefore, when the annular elastic body 23 is arranged on the bottom surface 64 side between the outer ring 21b and the cylindrical portion 61, the compressive force acting on the annular elastic body 23 is stabilized. As a result, the friction force that prevents the outer ring 21b from rotating relative to the cylindrical portion 61 is also stabilized, so that the occurrence of creep in the bearing 21 can be further prevented.

[0093] In addition, according to the motor 100 of the first embodiment, the bearing holding portion holding the bearing 21 on the load side is the metal bracket 6 formed of a galvanized steel plate. Since the galvanized steel plate can easily obtain higher dimensional accuracy than resin, the dimensional accuracy between the outer ring 21b of the bearing 21 and the metal bracket 6 can be managed with high accuracy. In addition, since the bearing holding portion (i.e., the holding portion 56b) holding the bearing 22 on the opposite side of the load is formed of BMC resin, the manufacturing cost of the motor 100 can be reduced.

[0094] Furthermore, the motor 100 of the first embodiment includes the annular elastic body 23 for preventing creep in the bearing 21 which is prone to creep. This can reduce the cost of the motor 100 compared to a structure that prevents creep in both the bearing 21 and the bearing 22.

[0095] In addition, in the alternating-pole rotor 1, when the radial excitation force acts on the bearings 21 and 22 supporting the shaft 15, there is a case where the oil film formed between the ball 21c and the raceway (the inner race 21a or the outer race 21b) is broken. In this case, since the ball 21c and the raceway are in direct contact without the oil film, when the shaft current flows in the bearings 21 and 22, electric corrosion is likely to occur. According to the first embodiment, the insulating sleeve 60 is arranged between the end 15b on the -z axis side of the shaft 15 and the bearing 22. As a result, since the shaft current can be prevented from flowing to the bearings 21 and 22 supporting the shaft 15, the occurrence of electric corrosion can be prevented.

[0096] In addition, according to the motor 100 of the first embodiment, since the rotor core 10 and the shaft 15 are connected by the connection portion 30 formed of the resin material having electrical insulation, it is possible to prevent the shaft current from flowing between the rotor core 10 and the shaft 15. Therefore, since the shaft current can be prevented from passing between the rotor core 10 and the shaft 15 and flowing in the bearings 21 and 22, it is possible to prevent the occurrence of electrical corrosion.

[0097] Implementation Method 2

[0098] Fig. 9 2 is an enlarged cross-sectional view showing the structure of the bearing 221 and its surroundings on the load side of the motor 200 according to the second embodiment. Fig. 9 In, with Figure 7 The same or corresponding components are marked with Figure 7 The motor 200 of the second embodiment is different from the motor 100 of the first embodiment in that a plurality of annular elastic bodies 23 and 24 are disposed between the outer ring 221 b of the bearing 221 on the load side and the cylindrical portion 61 of the metal bracket 6 .

[0099] like Fig. 9 As shown, the motor 200 has: a load-side bearing 221, the load-side bearing 221 supports the load side of the shaft 15; a metal bracket 6, the metal bracket 6 holds the load-side bearing 221; and a plurality of creep prevention parts (in Fig. 9 There are two annular elastic bodies 23 and 24.

[0100] The plurality of annular elastic bodies 23 and 24 are disposed between the outer peripheral surface 221f of the outer ring 221b and the inner peripheral surface 61a of the cylindrical portion 61. The number of annular elastic bodies 23 and 24 disposed between the outer ring 221b and the cylindrical portion 61 is not limited to two, and may be three or more.

[0101] The outer ring 221b includes a first groove portion 21d and a second groove portion 221e, which are formed at different positions in the axial direction on the outer peripheral surface 221f. In the second embodiment, the first groove portion 21d and the second groove portion 221e are arranged at symmetrical positions, for example, with the axial center position P of the ball 21c as a reference. An annular elastic body 23 is arranged in the first groove portion 21d. An annular elastic body 24 is arranged in the second groove portion 221e. Similar to the annular elastic body 23, the annular elastic body 24 is, for example, a rubber containing a thermosetting elastomer. In addition, similar to the annular elastic body 23, the annular elastic body 24 is, for example, an O-ring.

[0102] The friction coefficient between the annular elastic body 24 and the cylindrical portion 61 is greater than the friction coefficient between the outer ring 221b and the cylindrical portion 61. Therefore, when the plurality of annular elastic bodies 23 and 24 arranged between the outer peripheral surface 21f of the outer ring 221b and the inner peripheral surface 61a of the cylindrical portion 61 are compressed in the radial direction, the annular elastic bodies 23 and 24 increase the friction resistance in the circumferential direction R1 between the outer ring 221b and the cylindrical portion 61. As a result, since the outer ring 221b is difficult to rotate relative to the cylindrical portion 61, the occurrence of creep in the bearing 21 can be prevented.

[0103] According to the motor 200 of the second embodiment described above, a plurality of annular elastic bodies 23 and 24 are arranged between the outer peripheral surface 221f of the outer ring 221b and the inner peripheral surface 61a of the cylindrical portion 61. As a result, the friction resistance in the circumferential direction R1 between the outer peripheral surface 221f of the outer ring 221b and the inner peripheral surface 61a of the cylindrical portion 61 is further improved. Therefore, the occurrence of creep in the bearing 221 on the load side can be further prevented.

[0104] In addition, according to the motor 200 of the second embodiment, the plurality of annular elastic bodies 23 and 24 are arranged at symmetrical positions with respect to the axial center position P of the ball 21c. Thus, in the outer ring 221b, the wall thickness of the axial center portion where the load from the ball 21c acts can be ensured to be sufficient, and the plurality of annular elastic bodies 23 and 24 can be arranged.

[0105] In addition, regarding the points other than those described above, the motor 200 according to the second embodiment is the same as the motor 100 according to the first embodiment.

[0106] Implementation Method 3

[0107] Fig.10 2 is an enlarged cross-sectional view showing the structure around the bearing 321 on the load side of the motor 300 according to the third embodiment. Fig.10 In, with Figure 7 The same or corresponding components are marked with Figure 7The motor 300 is different from the motors 100 and 200 of the first or second embodiment in the structure of the creep prevention portion.

[0108] like Fig.10 As shown in FIG. 1 , the motor 300 includes a load-side bearing 321 that supports the load side of the shaft 15, a metal bracket 6 that holds the load-side bearing 321, and a resin member 323 as a creep prevention portion. The resin member 323 is disposed between the outer peripheral surface 321f of the outer ring 321b of the load-side bearing 321 and the inner peripheral surface 61a of the cylindrical portion 61 of the metal bracket 6.

[0109] The resin member 323 is formed of, for example, a thermoplastic elastomer. The resin member 323 is integrated with the outer ring 321b, for example, by integral molding, and thus is fixed to the outer ring 321b in advance. In addition, the resin member 323 may be fixed to the outer ring 321b in advance by an adhesive or the like. In addition, the resin member 323 may also be fixed to the metal bracket 6 in advance.

[0110] The friction coefficient between the resin member 323 and the cylindrical portion 61 is greater than the friction coefficient between the outer ring 321b and the cylindrical portion 61. That is, when the resin member 323 is arranged between the outer peripheral surface 321f of the outer ring 321b and the inner peripheral surface 61a of the cylindrical portion 61, the friction resistance in the circumferential direction R1 between the outer ring 321b and the cylindrical portion 61 can be increased. As a result, since the outer ring 321b is difficult to rotate relative to the cylindrical portion 61, the occurrence of creep in the bearing 321 on the load side can be prevented.

[0111] According to the motor 300 of the third embodiment described above, the resin member 323 is provided to increase the friction resistance in the circumferential direction R1 between the outer ring 321b and the cylindrical portion 61. As a result, the outer ring 321b is less likely to rotate relative to the cylindrical portion 61, thereby preventing creep from occurring in the load-side bearing 321.

[0112] Regarding the points other than those described above, the third embodiment is the same as either the first or second embodiment.

[0113] 《Variation of Implementation Method 3》

[0114] Fig.11 FIG. 2 is an enlarged cross-sectional view showing the structure of the bearing 321 and the surroundings of the motor 300A on the load side according to the modification of the third embodiment. Fig.11 In, with Figure 7 or Fig.10 The same or corresponding components are marked with Figure 7 or Fig.10The same reference numerals are used for the reference numerals shown. The motor 300A is different from the motor of any one of Embodiments 1 to 3 in the structure of the creep prevention unit.

[0115] like Fig.11 As shown in FIG. 1 , in the motor 300A, an adhesive 323A is interposed between the outer ring 321b of the bearing 321 on the load side and the inner peripheral surface of the cylindrical portion 61 of the metal bracket 6. In the motor 300A, the outer peripheral surface 321f of the outer ring 321b and the inner peripheral surface 61a of the cylindrical portion 61 are fixed to each other by the adhesive 323A. As a result, the outer ring 321b is difficult to rotate relative to the cylindrical portion 61.

[0116] According to the motor 300A of the modified example of the third embodiment described above, the adhesive 323A is interposed between the outer peripheral surface 321f of the outer ring 321b and the inner peripheral surface 61a of the cylindrical portion 61, and the outer peripheral surface 321f of the outer ring 321b and the inner peripheral surface 61a of the cylindrical portion 61 are fixed to each other. As a result, since the outer ring 321b is difficult to rotate relative to the cylindrical portion 61, the occurrence of creep in the bearing 321 on the load side can be prevented.

[0117] Implementation Method 4

[0118] Fig.12 (A) is an enlarged cross-sectional view showing the structure around the bearing 421 on the load side of the electric motor 400 according to the fourth embodiment. Fig.12 (B) Yes Fig.12 (A) is a partial front view of the outer peripheral surface 421f of the outer ring 421b. Fig.12 (A) Figure 7 The same or corresponding components are marked with Figure 7 The same reference numerals are used for the reference numerals shown. The motor 400 is different from the motor of any one of the first to third embodiments in the structure of the creep prevention unit.

[0119] like Fig.12 As shown in (A) and (B), the motor 400 has: a load-side bearing 421, which supports the load side of the shaft 15; a metal bracket 6, which holds the load-side bearing 421; and a concave-convex surface 423 as a creep prevention portion. The concave-convex surface 423 is formed on the outer peripheral surface 421f of the outer ring 421b. The concave-convex surface 423 is formed, for example, on the entire axial direction of the outer peripheral surface 421f. In addition, the concave-convex surface 423 can also be formed on at least a portion of the outer peripheral surface 421f.

[0120] like Fig.12As shown in (B), the concavoconvex surface 423 has a convex portion 423g and a concave portion 423h. The concavoconvex surface 423 is formed, for example, by shot peening the outer peripheral surface 421f of the outer ring 421b. The surface roughness Ra of the concavoconvex surface 423 in the processed outer peripheral surface 421f is greater than the surface roughness Ra of the outer peripheral surface 421f before processing. The surface roughness Ra of the outer peripheral surface 421f before processing is, for example, 0.025μm to 0.2μm. The surface roughness Ra of the outer peripheral surface 421f after processing is, for example, 0.2μm to 20μm. Here, the surface roughness Ra is the "arithmetic mean roughness" defined in JIS B0601:2013.

[0121] The friction coefficient between the concavoconvex surface 423 and the inner circumferential surface 61a of the cylindrical portion 61 is greater than the friction coefficient between the outer circumferential surface 421f (i.e., the surface other than the concavoconvex surface 423) before processing and the inner circumferential surface 61a of the cylindrical portion 61. As a result, the friction resistance between the outer ring 421b and the cylindrical portion 61 in the circumferential direction R1 is increased.

[0122] According to the motor 400 of the fourth embodiment described above, the concavoconvex surface 423 that increases the friction resistance in the circumferential direction R1 between the outer ring 421b and the cylindrical portion 61 is formed on the outer peripheral surface 421f of the outer ring 421b. As a result, the outer ring 421b is difficult to rotate relative to the cylindrical portion 61, and therefore, the occurrence of creep in the bearing 421 on the load side can be prevented.

[0123] Regarding points other than those described above, the fourth embodiment is the same as any one of the first to third embodiments.

[0124] Implementation Method 5

[0125] Fig.13 FIG. 2 is an enlarged cross-sectional view showing the structure around the bearing 521 on the load side of the motor 500 according to the fifth embodiment. Fig.13 In, with Figure 7 The same or corresponding components are marked with Figure 7 The same reference numerals are used for the reference numerals shown. The motor 500 is different from the motor of any one of Embodiments 1 to 4 in the structure of the creep prevention unit.

[0126] like Fig.13 As shown, the motor 500 has: a bearing 521 on the load side, which supports the load side of the shaft 15; a metal bracket 6, which holds the bearing 521 on the load side; a preload spring 45, which is arranged between the metal bracket 6 and the bearing 521 on the load side; and a resin component 546 as a creep prevention portion.

[0127] The resin member 546 is disposed between the bearing 521 on the load side and the preload spring 45. The resin member 546 contacts the preload spring 45 and the end face 521i of the outer ring 521b. In other words, in the fifth embodiment, the preload spring 45 exerts the end face 521i of the outer ring 521b toward the molded stator 9 (see Figure 1 ) pressing force. The resin member 546 is formed of, for example, a thermoplastic elastomer. The resin member 546 is, for example, an annular member centered on the axis C1. The resin member 546 has a through hole 546a through which the shaft 15 passes.

[0128] The friction coefficient between the resin member 546 and the outer ring 521b is greater than the friction coefficient between the outer ring 521b and the preload spring 45. By arranging the resin member 546 between the outer ring 521b and the preload spring 45, the friction resistance between the outer ring 521b and the preload spring 45 is increased. As a result, since the pressing force of the preload spring 45 is stabilized, the friction resistance of the outer ring 521b in the circumferential direction R1 can also be increased between the outer ring 521b and the cylindrical portion 61. Therefore, the outer ring 521b is difficult to rotate relative to the cylindrical portion 61, and the occurrence of creep in the bearing 521 on the load side can be prevented. In addition, in the fifth embodiment, the creep prevention portion arranged between the bearing 521 on the load side and the preload spring 45 is not limited to the resin member 546, and may also be other members such as an elastomer (e.g., rubber) or an adhesive.

[0129] According to the motor 500 of the fifth embodiment described above, a creep prevention portion (for example, a resin member 546) is arranged between the outer ring 521b and the preload spring 45 to increase the friction resistance between the outer ring 521b and the preload spring 45. As a result, the friction resistance in the circumferential direction R1 between the outer ring 521b and the cylindrical portion 61 is also increased. Therefore, since the outer ring 521b is difficult to rotate relative to the cylindrical portion 61, the occurrence of creep in the load-side bearing 521 can be prevented.

[0130] Regarding the points other than those described above, the fifth embodiment is the same as any one of the first to fourth embodiments.

[0131] Implementation Method 6

[0132] Fig.14 1 is a structural diagram showing a partial cross section and side view of a motor 600 according to a sixth embodiment. Fig.14 In, with Figure 1 The same or corresponding components are marked with Figure 1 The motor 600 is different from the motor 100 of the first embodiment in that it further includes a second creep prevention unit that prevents creep in the bearing 622 on the opposite side of the load.

[0133] like Fig.14 As shown, the motor 600 has an annular elastic body 23 as a first creep prevention portion and a plurality of (in Fig.14 The plurality of annular elastic bodies 623 and 624 are disposed between the outer ring 622b of the bearing 622 and the retaining portion 56b of the molded resin portion 56. The plurality of annular elastic bodies 623 and 624 are, for example, rubbers containing thermosetting elastomers. In addition, similar to the annular elastic body 23, the plurality of annular elastic bodies 623 and 624 are, for example, O-rings. In addition, the number of annular elastic bodies 623 and 624 disposed between the outer ring 622b and the retaining portion 56b is not limited to two, and may be one or more.

[0134] The annular elastic bodies 623 and 624 disposed between the outer ring 622b and the retaining portion 56b are compressed in the radial direction, so that the friction force that prevents the outer ring 622b from rotating relative to the retaining portion 56b is exerted. That is, when the annular elastic bodies 623 and 624 are disposed between the outer ring 622b and the retaining portion 56b, the friction resistance in the circumferential direction R1 between the outer ring 622b and the retaining portion 56b is increased. Thus, creep can also be prevented in the bearing 622 on the opposite side of the load.

[0135] According to the electric motor 600 of the sixth embodiment described above, the occurrence of creep can be prevented in each of the bearing 21 on the load side and the bearing 622 on the opposite side of the load.

[0136] Regarding points other than those described above, the sixth embodiment is the same as any one of the first to fifth embodiments.

[0137] 《Variation 1 of Implementation Example 6》

[0138] Next, Modification 1 of Implementation Example 6 is described. Fig.15 1 is a partial cross-sectional and side structural diagram showing a motor 600A according to a first variation of the sixth embodiment. Fig.15 In, with Fig.14 The same or corresponding components are marked with Fig.14 The motor 600A is different from the motor 600 of the sixth embodiment in the material of the holding portion 82 holding the bearing 622 on the opposite side of the load and the number of annular elastic bodies 624 disposed between the bearing 622 and the holding portion 82 .

[0139] like Fig.15As shown, the motor 600A has a cover member 80 fixed to the end of the molded resin portion 56 on the -z axis side. The cover member 80 is formed of metal. The cover member 80 is formed of, for example, a hot-dip galvanized aluminum-magnesium alloy steel plate. Since the hot-dip galvanized aluminum-magnesium alloy steel plate can be stamped, it has good processability, and therefore, it is easy to obtain high dimensional accuracy. In addition, compared with general resins such as BMC and PBT, the thermal conductivity is higher.

[0140] The cover member 80 includes a flange portion 81 fixed to the molded resin portion 56 and a retaining portion 82 located radially inward of the flange portion 81. The retaining portion 82 retains the bearing 622. That is, in the first modification of the sixth embodiment, the retaining portion 82 as the second retaining portion for retaining the bearing 622 on the opposite side to the load is formed of metal.

[0141] Fig.16 It is shown Fig.15 FIG. 6 is an enlarged cross-sectional view of the structure around the bearing 622 of the motor 600A. Fig.16 As shown, the bearing 622 has: an inner ring 622a, which supports the end 15b on the -z axis side of the shaft 15 via an insulating sleeve 60; an outer ring 622b, which is fixed to the retaining portion 82 in a clearance fit manner; and balls 622c as rolling bodies, which are arranged between the inner ring 622a and the outer ring 622b.

[0142] The flange portion 81 has a first surface 81 a that contacts the axial end surface of the end portion 556 b on the −z-axis side of the mold resin portion 56 , and a second surface 81 b that contacts the inner surface of the end portion 556 b .

[0143] The retaining portion 82 has a cylindrical surface 83, a contact surface 84, and a separation surface 85. The cylindrical surface 83 is radially opposed to a portion of the outer peripheral surface 622f of the outer ring 622b. The contact surface 84 is in contact with the end surface 622g of the outer ring 622b on the -z axis side in the axial direction. The separation surface 85 is adjacent to the radial inner side of the contact surface 84 in a separated manner, and is separated from the inner ring 622a of the bearing 622 and the shaft 15 toward the -z axis side. That is, the retaining portion 82 is in contact with the outer ring 622b, but not with the inner ring 622a and the shaft 15. As a result, it is possible to suppress the shaft current flowing in the shaft 15 from passing through the retaining portion 82 and the inner ring 622a and passing through the ball 622c.

[0144] An annular elastic body 624 is arranged between the outer peripheral surface 622f of the outer ring 622b and the cylindrical surface 83 of the retaining portion 82. The annular elastic body 624 is arranged in a groove 622d formed in the outer peripheral surface 622f of the outer ring 622b. The groove 622d is formed on the -z axis side in the outer peripheral surface 622f with the axial position of the center of the ball 622c as a reference.

[0145] The friction coefficient between the annular elastic body 624 and the cylindrical surface 83 is greater than the friction coefficient between the outer peripheral surface 622f and the cylindrical surface 83. That is, when the annular elastic body 624 is arranged between the outer peripheral surface 622f and the cylindrical surface 83, the friction resistance in the circumferential direction R1 between the outer ring 622b and the cylindrical surface 83 of the retaining portion 82 is increased. As a result, the outer ring 622b is difficult to rotate relative to the retaining portion 82, and the occurrence of creep in the bearing 622 can be prevented.

[0146] According to the electric motor 600A of the variant example 1 of the above-described embodiment 6, when the bearing retaining portion for retaining the bearing 21 on the load side and the bearing retaining portion for retaining the bearing 622 on the opposite side of the load are both formed of metal, the occurrence of creep in each of the bearing 21 on the load side and the bearing 622 on the opposite side of the load can be prevented.

[0147] 《Variation 2 of Implementation Example 6》

[0148] Next, a second variation of the sixth embodiment will be described. Fig.17 FIG. 2 is a structural diagram showing a partial cross section and side surface of a motor 600B according to a second variation of the sixth embodiment. Fig.17 In, with Fig.15 The same or corresponding components are marked with Fig.15 The motor 600B differs from the motor 600A of the first modification of the sixth embodiment in the material of the holding portion 556c holding the load-side bearing 21 and the number of annular elastic bodies 23 and 24 disposed between the bearing 21 and the holding portion 556c.

[0149] like Fig.17 As shown, the molded stator 9 of the motor 600B has a molded resin portion 556 covering the stator core 50. The molded resin portion 556 has a retaining portion 556c as a first retaining portion formed on the +z axis side. The bearing 21 is retained in the retaining portion 556c. That is, in the second modification of the sixth embodiment, the bearing retaining portion that retains the bearing 21 on the load side is formed of resin. A preload spring 45 that applies a force that presses the end surface of the outer ring 21b on the +z axis side toward the molded stator 9 is arranged between the bearing 21 and the retaining portion 556c.

[0150] A plurality of (at Fig.17The annular elastic bodies 23 and 24 are two in the figure. The friction coefficient between the annular elastic bodies 23 and 24 and the retaining portion 556c is greater than the friction coefficient between the outer ring 21b and the retaining portion 556c. That is, when the annular elastic bodies 23 and 24 are arranged between the outer ring 21b and the retaining portion 556c, the friction resistance in the circumferential direction R1 between the outer ring 21b and the retaining portion 556c is increased. As a result, since the outer ring 21b is difficult to rotate relative to the retaining portion 556c, the occurrence of creep in the bearing 21 can be prevented. In addition, the number of annular elastic bodies 23 and 24 arranged between the outer ring 21b and the retaining portion 556c is not limited to two, as long as it is one or more.

[0151] According to the electric motor 600B of the variant example 2 of the above-described embodiment 6, when the bearing retaining portion for retaining the bearing 21 on the load side is formed of resin and the bearing retaining portion for retaining the bearing 622 on the opposite side of the load is formed of metal, the occurrence of creep in each of the bearing 21 on the load side and the bearing 622 on the opposite side of the load can be prevented.

[0152] In addition, when the holding portion 556c holding the load-side bearing 21 is formed of resin, the holding portion 556c is easily worn when the bearing 21 creeps. According to the motor 600B of the second modification of the sixth embodiment, since the creep in the bearing 21 can be prevented, the wear in the holding portion 556c can be prevented.

[0153] 《Variation 3 of Implementation Example 6》

[0154] Next, variation 3 of embodiment 6 is described. Fig.18 1 is a partial cross-sectional and side structural diagram showing a motor 600C according to a third variation of the sixth embodiment. Fig.18 In, with Fig.14 The same or corresponding components are marked with Fig.14 The motor 600C is different from the motor 600 of the sixth embodiment in the material of the bearing holding portion (resin bracket 90 described later) that holds the bearing 21 and the number of annular elastic bodies 23 and 24 disposed between the bearing 21 and the holding portion 556c.

[0155] like Fig.18As shown, the motor 600C has a resin bracket 90 as a first retaining portion for retaining the bearing 21. It is fixed to the opening portion 56a of the molded resin portion 56. The resin bracket 90 is fixed to the opening portion 56a by, for example, press-fitting. The resin bracket 90 is formed of, for example, BMC resin. The resin bracket 90 has a cylindrical portion 91 that is radially opposed to the outer ring 21b of the bearing 21. The cylindrical portion 91 extends substantially parallel to the axis C1. A preload spring 45 that applies a force that presses the end surface of the outer ring 21b on the +z axis side toward the molded stator 9 is arranged between the bearing 21 and the resin bracket 90. In addition, the shape of the resin bracket 90 is not limited to Fig.18 The shape shown is sufficient as long as it has a cylindrical portion 91 that faces the outer ring 21 b in the radial direction, and other shapes may be used.

[0156] A plurality of (in the Fig.18 There are two annular elastic bodies 23 and 24. Thus, creep can be prevented in the bearing 21. In addition, the number of annular elastic bodies 23 and 24 arranged between the outer ring 21b and the cylindrical portion 91 is not limited to two, and it only needs to be one or more.

[0157] According to the electric motor 600C of the variant example 3 of the above-described embodiment 6, when the bearing retaining portion for retaining the bearing 21 on the load side and the bearing retaining portion for retaining the bearing 622 on the opposite side of the load are both formed of resin, the occurrence of creep in each of the bearing 21 on the load side and the bearing 622 on the opposite side of the load can be prevented.

[0158] 〈Air conditioning equipment〉

[0159] Next, an air conditioning device 700 to which the electric motor of any one of Embodiments 1 to 6 is applied will be described. In the following description, the air conditioning device 700 to which the electric motor 100 of Embodiment 1 is applied will be described as an example.

[0160] Fig.19 is a diagram showing the structure of the air conditioning device 700. Fig.19 As shown, the air conditioner 700 includes an outdoor unit 701, an indoor unit 702, and a refrigerant pipe 703 connecting the outdoor unit 701 and the indoor unit 702. In the air conditioner 700, for example, a cooling operation in which cold air is blown from the indoor unit 702 or a heating operation in which warm air is blown can be performed.

[0161] The outdoor unit 701 includes an outdoor fan 150 as a fan, a frame 707 that supports the outdoor fan 150 , and a casing 708 that covers the outdoor fan 150 and the frame 707 .

[0162] Fig. 20 It is shown Fig.19 The cross-sectional view of the structure of the outdoor unit 701 is shown. Fig. 20 As shown, the outdoor blower 150 of the outdoor unit 701 includes a motor 100 mounted on a frame 707 and an impeller 704 mounted on the shaft 15 of the motor 100. The impeller 704 includes a hub 705 fixed to the shaft 15 and blades 706 provided on the outer periphery of the hub 705. The impeller 704 is, for example, a propeller fan.

[0163] When the motor 100 drives the impeller 704, the impeller 704 rotates and generates airflow. As a result, the outdoor blower 150 can blow air. For example, during the cooling operation of the air conditioning device 700, the heat released when the refrigerant compressed by the compressor (not shown) is condensed in the condenser (not shown) is released to the outside through the air blowing of the outdoor blower 150.

[0164] In the motor of any one of the above-mentioned embodiments 1 to 6, since vibration and noise caused by creep can be prevented, the quietness of the outdoor blower 150 is improved. As a result, the quietness of the outdoor unit 701 having the outdoor blower 150 is also improved. In addition, in the motor 100 of embodiment 1, since the occurrence of creep in the bearing 21 can be prevented at low cost, the cost reduction of the air conditioning device 700 equipped with the motor 100 can be sought.

[0165] Furthermore, the motor of any one of Embodiments 1 to 6 may be provided in other blowers (e.g., indoor blowers of indoor unit 702) other than outdoor blower 150 of outdoor unit 701. Furthermore, the motor of any one of Embodiments 1 to 6 may be provided in other home appliances other than air conditioners.

[0166] Description of Reference Numerals

[0167] 1 rotor, 6 metal bracket (bearing holding portion, first holding portion), 9 molded stator (stator), 15 shaft (rotating shaft), 15b portion on the opposite side of the load, 15c portion on the load side, 21 bearing (first bearing), 21b outer ring, 21f outer peripheral surface, 21i end surface, 22 bearing (second bearing), 23, 24, 623, 624 annular elastic body (elastic member), 45 preload spring, 56b holding portion (bearing holding portion, second holding portion), 61a inner peripheral surface (inner surface) , 82 retaining part (bearing retaining part, second retaining part), 90 resin bracket (bearing retaining part, first retaining part), 100, 200, 300, 300A, 400, 500, 600, 600A, 600B, 600C electric motor, 150 outdoor blower (blower), 323 resin component, 323A adhesive, 423 concave and convex surface, 546 resin component, 556c retaining part (bearing retaining part, first retaining part), 700 air conditioning device, P center position.

Claims

1. An electric motor, wherein: The electric motor has: stator; an alternating pole rotor having an axis of rotation; A bearing, wherein the bearing is a rolling bearing that supports the rotating shaft; a bearing holding portion, the bearing holding portion being fixed to the stator and holding an outer ring of the bearing; and a creep prevention portion, the creep prevention portion being arranged between the outer ring and the bearing holding portion to increase the friction resistance of the outer ring in the circumferential direction between the outer ring and the bearing holding portion, The friction coefficient between the creep prevention portion and the bearing holding portion is greater than the friction coefficient between the outer ring and the bearing holding portion. The creep prevention portion includes an annular elastic body disposed between the outer peripheral surface of the outer ring and the inner peripheral surface of the bearing holding portion.

2. The electric motor according to claim 1, wherein: The outer ring has a groove formed on the outer peripheral surface of the outer ring. The annular elastic body is arranged in the groove portion.

3. The electric motor according to claim 1, wherein: The annular elastic body is an O-ring.

4. The electric motor according to any one of claims 1 to 3, wherein: The annular elastic body is disposed between the outer peripheral surface of the outer ring and the inner peripheral surface of the bearing holding portion at a position offset to one side in the axial direction of the rotating shaft with reference to the center of the rolling element of the bearing.

5. The electric motor according to any one of claims 1 to 3, wherein: The bearing holding portion includes: a cylindrical portion, the cylindrical portion facing the outer ring in the radial direction of the rotating shaft; and a bottom portion, the bottom portion extending from the cylindrical portion toward the inner side in the radial direction. The creep prevention portion is disposed between the outer peripheral surface of the outer ring and the inner peripheral surface of the cylindrical portion on the bottom surface side with reference to the central position in the axial direction of the rolling element of the bearing.

6. The electric motor according to any one of claims 1 to 3, wherein: The creep prevention portion has a concavo-convex surface formed on an outer peripheral surface of the outer ring and in contact with an inner peripheral surface of the bearing holding portion.

7. The electric motor according to claim 6, wherein: A first friction coefficient between the concavo-convex surface and an inner peripheral surface of the bearing holding portion is larger than a second friction coefficient between a surface of the outer ring other than the concavo-convex surface and the inner peripheral surface of the bearing holding portion.

8. The electric motor according to any one of claims 1 to 3, wherein: The motor further includes a preload spring, which is disposed between the bearing and the bearing holding portion and applies a force that presses an end surface of the outer ring in the axial direction of the rotating shaft toward the stator. The creep prevention portion includes a member disposed between the end surface of the outer ring and the preload spring.

9. The electric motor according to any one of claims 1 to 3, wherein: The bearing supports a portion on the load side or a portion on the opposite side of the rotation shaft.

10. The electric motor according to any one of claims 1 to 3, wherein: The bearing holding portion is formed of at least one of metal and resin.

11. The electric motor according to any one of claims 1 to 3, wherein: The bearing includes a first bearing and a second bearing, wherein the first bearing and the second bearing are arranged on opposite sides of the stator. The bearing holding portion includes: a first holding portion, the first holding portion holding a first outer ring of the first bearing; and a second holding portion, the second holding portion holding a second outer ring of the second bearing. The annular elastomer includes: a first annular elastomer, which increases the friction resistance of the first outer ring in the circumferential direction between the first outer ring and the first retaining portion; and a second annular elastomer, which increases the friction resistance of the second outer ring in the circumferential direction between the second outer ring and the second retaining portion.

12. The electric motor according to claim 11, wherein The first holding portion is formed of metal, The second holding portion is formed of resin.

13. The electric motor according to claim 11, wherein The first retaining portion is formed of a galvanized steel plate, The second holding portion is formed of BMC resin.

14. The electric motor according to claim 11, wherein The first holding portion and the second holding portion are both formed of metal.

15. The electric motor according to claim 11, wherein The first holding portion and the second holding portion are both formed of resin.

16. A blower, wherein: The blower has: The electric motor according to any one of claims 1 to 15; and An impeller is rotated by the motor.

17. An air conditioning device, wherein: The air conditioning device comprises: Outdoor unit; as well as an indoor unit connected to the outdoor unit via a refrigerant pipe, At least one of the outdoor unit and the indoor unit includes the air blower according to claim 16.

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