Motor, blower, and air conditioning device

Abstract

This motor includes: a rotor; a rotary shaft fixed to the rotor, said rotary shaft projecting from the rotor to first and second sides in the axial direction of the rotary shaft, the extent of projection on the first side being greater than the the extent of projection on the second side; a stator facing the rotor in the radial direction of the rotary shaft; a first bearing supporting the rotary shaft on the first side; a second bearing supporting the rotary shaft on the second side; a conductive bracket holding the second bearing; and a metal rod provided between the second-side end surface of the rotary shaft and the bracket. The metal rod has a contact part that contacts the end surface of the rotary shaft, the contact part being movable in the axial direction. The bracket has a through hole.

Description

Motors, blowers and air conditioners

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

[0002] It is known that damage known as electrolytic corrosion occurs in motors due to a potential difference between the inner and outer rings of the bearings that support the rotating shaft. For example, Patent Document 1 proposes a configuration in which a conductive brush is placed in contact with the axial end face of the motor's rotating shaft and the brush is grounded in order to suppress the occurrence of electrolytic corrosion.

[0003] JP 2015-50798 A (see FIG. 1)

[0004] However, a configuration in which brushes contact the axial end faces of the rotating shaft increases the size of the motor in the axial direction. Furthermore, brushes are expensive components, which increases the manufacturing cost of the motor. Therefore, there is a need for technology that can suppress electrolytic corrosion in bearings while preventing the motor from becoming larger and the manufacturing cost from increasing.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to suppress the occurrence of electrolytic corrosion in bearings while preventing an increase in the size of the motor and an increase in manufacturing costs.

[0006] The motor disclosed herein includes a rotor, a rotating shaft fixed to the rotor, the rotating shaft protruding from the rotor to a first side and a second side in the axial direction of the rotating shaft, the first side protruding by a larger amount than the second side, a stator facing the rotor in the radial direction of the rotating shaft, a first bearing supporting the rotating shaft on the first side, a second bearing supporting the rotating shaft on the second side, a conductive bracket holding the second bearing, and a metal rod provided between the bracket and an end face of the second side of the rotating shaft. The metal rod has a contact portion that contacts the end face of the rotating shaft and is axially movable. The bracket has a through hole.

[0007] In this disclosure, the metal rod and bracket provide electrical continuity between the outer ring of the bearing and the rotating shaft, reducing the potential difference between the inner and outer rings of the bearing and suppressing electrolytic corrosion. Because brushes are not required, the motor's size and manufacturing costs can be prevented from increasing. Furthermore, the metal rod can be fixed to the bracket through a through-hole in the bracket, simplifying the assembly process and reducing manufacturing costs.

[0008] FIG. 1 is a cross-sectional view showing a motor according to a first embodiment. FIG. 2 is a cross-sectional view showing a rotor and a stator according to the first embodiment. FIG. 3 is a schematic diagram showing an example of the configuration of a metal rod according to the first embodiment. FIG. 4 is a schematic diagram for explaining forces acting on each bearing according to the first embodiment. FIG. 4 is a cross-sectional view showing a first example of a mounting structure for a metal rod in a bracket according to the first embodiment. FIG. 5 is a schematic diagram for explaining a method of welding a metal rod to a bracket according to the first embodiment. FIG. 6 is a cross-sectional view showing a second example of a mounting structure for a metal rod in a bracket according to the first embodiment. FIG. 7 is a cross-sectional view showing a third example of a mounting structure for a metal rod in a bracket according to the first embodiment. FIG. 8 is a cross-sectional view showing a motor according to a second embodiment. FIG. 9 is a cross-sectional view showing a motor according to a third embodiment. FIG. 10 is a cross-sectional view showing an enlarged portion of the motor according to the third embodiment. FIG. 11 is a cross-sectional view showing a motor according to a fourth embodiment. FIG. 12 is a diagram showing a contact portion between a rotating shaft and a metal rod in modified examples 1 and 2. FIG. 13 is a cross-sectional view showing a motor according to modified example 3. FIG. 14 is a diagram showing an air conditioning device to which the motors of the respective embodiments can be applied, and FIG. 15 is a diagram showing an outdoor unit of the air conditioning device.

[0009] Embodiment 1. <Overall Configuration of Motor 1> A motor 1 according to embodiment 1 will now be described. Fig. 1 is a cross-sectional view showing the motor 1 according to embodiment 1. The motor 1 is used, for example, in an outdoor fan 110 (Fig. 15(B)) of an air conditioning apparatus 100.

[0010] The motor 1 includes a rotating shaft 10, a rotor 21 fixed to the rotating shaft 10, a stator 22 surrounding the rotor 21, bearings 11 and 12 supporting the rotating shaft 10, and a frame 31 and a bracket 32 ​​accommodating these components. The central axis Ax of the rotating shaft 10 defines the center of rotation of the rotor 21.

[0011] Hereinafter, the direction of the central axis Ax will be referred to as the "axial direction." The radial direction centered on the central axis Ax will be referred to as the "radial direction." The circumferential direction centered on the central axis Ax will be referred to as the "circumferential direction."

[0012] The rotating shaft 10 protrudes from the rotor 21 to a first side (upper side in FIG. 1 ) and a second side (lower side in FIG. 1 ) in the axial direction. The amount of protrusion of the rotating shaft 10 from the rotor 21 is greater on the first side than on the second side. Therefore, the first side is also referred to as the long axis side, and the second side is also referred to as the short axis side. Note that the first side is not limited to the upper side, and the second side is not limited to the lower side.

[0013] The rotating shaft 10 is rotatably supported by a bearing 11 arranged on a first side of the rotor 21 and a bearing 12 arranged on a second side thereof. The bearing 11 is also referred to as a first bearing or a long shaft side bearing, and the bearing 12 is also referred to as a second bearing or a short shaft side bearing.

[0014] The rotating shaft 10 protrudes in the axial direction on both sides from the bearings 11 and 12. The amount of protrusion of the rotating shaft 10 in the axial direction from the bearing 11 is greater than the amount of protrusion of the rotating shaft 10 in the axial direction from the bearing 12.

[0015] The rotating shaft 10 has a circular cross section and is made of a conductive material such as a metal. The metal may be carbon steel (S45C). The outer diameter Ds (FIG. 5) of the rotating shaft 10 is, for example, 8 mm or more.

[0016] <Configuration of Rotor 21> Fig. 2 is a cross-sectional view showing the rotor 21 and the stator 22. As shown in Fig. 2, the rotor 21 has a rotor core 21a fixed to the rotating shaft 10 and a plurality of permanent magnets 21b embedded in the rotor core 21a.

[0017] The rotor core 21a is a cylindrical member centered on the central axis Ax. The rotor core 21a is made of a laminate of multiple electromagnetic steel sheets. The thickness of the electromagnetic steel sheets is, for example, 0.1 mm to 1.0 mm. A shaft hole 21d is formed in the center of the rotor core 21a, and the rotating shaft 10 is fixed therein.

[0018] The rotor core 21a has a plurality of magnet insertion holes 21c in the circumferential direction. The magnet insertion holes 21c are arranged at equal intervals in the circumferential direction and at equal distances from the central axis Ax. The number of magnet insertion holes 21c is 10 in this example, but is not limited to this. The magnet insertion holes 21c penetrate the rotor core 21a in the axial direction.

[0019] A flat permanent magnet 21b is inserted into each magnet insertion hole 21c. The permanent magnets 21b in the magnet insertion holes 21c form magnetic poles. There are ten permanent magnets 21b, and therefore the rotor 21 has ten poles. However, the number of poles of the rotor 21 is not limited to ten, and may be any number equal to or greater than two.

[0020] The permanent magnets 21b are, for example, rare earth magnets. However, they are not limited to rare earth magnets and may be ferrite magnets. Furthermore, the rotor 21 is not limited to one in which the permanent magnets 21b are embedded in the rotor core 21a, but may be one in which the permanent magnets 21b are attached to the surface of the rotor core 21a.

[0021] <Configuration of Stator 22> The stator 22 includes a stator core 22a, a winding 22b wound around the stator core 22a, and an insulating portion 22c disposed therebetween. The stator core 22a is formed by laminating a plurality of electromagnetic steel sheets. The thickness of the electromagnetic steel sheets is, for example, 0.1 mm to 1.0 mm.

[0022] The stator core 22 a includes an annular yoke 22 d centered on the central axis Ax and a plurality of teeth 22 e extending radially inward from the yoke 22 d. The number of teeth 22 e is, for example, 12, but is not limited to this.

[0023] The windings 22b are made of copper or aluminum conductors covered with an insulating film. The windings 22b are wound around the teeth 22e via insulating portions 22c. The insulating portions 22c are made of PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), or the like.

[0024] The rotor 21 and the stator 22 are collectively referred to as the motor section 20. The motor section 20 is housed in a housing made up of a frame 31 and a bracket 32. The motor 1 is made up of the rotating shaft 10, the motor section 20, the frame 31, the bracket 32, the bearings 11 and 12, and a metal rod 15, which will be described later.

[0025] <Configuration of Frame 31 and Bracket 32> Next, the frame 31 and bracket 32 ​​shown in Fig. 1 will be described. In the first embodiment, both the frame 31 and the bracket 32 ​​are formed of a conductor such as a metal. For example, aluminum is used as the metal. The frame 31 and the bracket 32 ​​form a housing.

[0026] The frame 31 has an annular portion 31a that holds the bearing 11 from the radial outside, a lid portion 31b formed on the long axis side of the annular portion 31a, a peripheral wall portion 31d that surrounds the motor portion 20 from the radial outside, and a plate-shaped portion 31c that extends from the annular portion 31a to the peripheral wall portion 31d.

[0027] The annular portion 31a is formed in an annular shape centered on the central axis Ax, and the bearing 11 is disposed inside the annular portion 31a. The annular portion 31a is formed in the radial center of the disk-shaped plate-like portion 31c. The annular portion 31a may protrude in the axial direction from the plate-like portion 31c (see FIG. 4).

[0028] The cover portion 31b is formed in a disk shape so as to cover the long axis side (upper side in the figure) of the annular portion 31a, and faces the bearing 11 in the axial direction. A through hole is formed in the center of the cover portion 31b to allow the rotating shaft 10 to pass through in the axial direction.

[0029] The peripheral wall portion 31d is formed in a cylindrical shape centered on the central axis Ax and radially surrounds the motor portion 20. The stator 22 of the motor portion 20 is fitted to the inner periphery of the peripheral wall portion 31d. The plate-like portion 31c extends in a direction perpendicular to the central axis Ax, from the annular portion 31a to the peripheral wall portion 31d.

[0030] The portion of the frame 31 that includes the annular portion 31 a, the cover portion 31 b, and the plate-like portion 31 c is also referred to as a first bracket or a long-axis-side bracket. In contrast, the bracket 32, which will be described next, is also referred to as a second bracket or a short-axis-side bracket.

[0031] The bracket 32 ​​has a first accommodating portion 32a that holds the bearing 12, a second accommodating portion 32b formed on the short axis side (lower side in Figure 1) of the first accommodating portion 32a, and a plate-shaped portion 32f that extends from the first accommodating portion 32a to the peripheral wall portion 31d of the frame 31.

[0032] The first housing portion 32a is a cylindrical portion centered on the central axis Ax. A bearing 12 is disposed in a space S1 inside the first housing portion 32a. A bottom portion 32c is formed at the end portion on the minor axis side of the first housing portion 32a (the lower end portion in FIG. 1).

[0033] A preload spring 13 serving as a preload member is disposed in the space S1 inside the first housing portion 32a adjacent to the minor axis side of the bearing 12. The preload spring 13 is a spring member, more specifically a wave washer. The preload spring 13 is compressed in the axial direction between the bottom portion 32c of the first housing portion 32a and the bearing 12.

[0034] The second housing portion 32b is a cylindrical portion centered on the central axis Ax. The inner diameter of the second housing portion 32b is smaller than the inner diameter of the first housing portion 32a. A metal rod 15, which will be described below, is disposed in a space S2 inside the second housing portion 32b. A bottom portion 32d is formed at the end of the second housing portion 32b on the minor axis side (the lower end portion in FIG. 1).

[0035] <Configuration of Metal Rod 15> The metal rod 15 is a pin or wire rod made of a conductive metal. The metal rod 15 is formed of, for example, carbon steel (S45C), stainless steel, or aluminum. The metal rod 15 is also called a conductive pin.

[0036] The cross-sectional shape of the metal rod 15 is, for example, circular, but may be other shapes. The metal rod 15 contacts the axial end face of the rotating shaft 10. Hereinafter, the axial end face of the rotating shaft 10 will be referred to as the "end face of the rotating shaft 10."

[0037] 3A and 3B are diagrams showing examples of the shape of the metal rod 15. As shown in Fig. 3A, the metal rod 15 has a contact portion 15a that contacts the end face of the rotating shaft 10 and a biasing portion 15b that biases the contact portion 15a toward the rotating shaft 10. The contact portion 15a extends linearly in the axial direction, and its tip contacts the end face of the rotating shaft 10.

[0038] The biasing portion 15b extends spirally around the central axis Ax. One end of the biasing portion 15b is connected to the contact portion 15a, and the other end of the biasing portion 15b is in contact with the bottom portion 32d of the second housing portion 32b. The biasing portion 15b is also referred to as a spring portion. In addition, the biasing portion 15b is also referred to as a movable portion because it allows the metal rod 15 to change its position in the axial direction.

[0039] In the example shown in Fig. 3(A), the biasing portion 15b has a cylindrical spiral shape with a constant outer diameter in the axial direction. However, as shown in Fig. 3(B), the biasing portion 15b may have a conical spiral shape with an outer diameter that increases with increasing distance from the contact portion 15a. Although the contact portion 15a and the biasing portion 15b are integrally formed in Figs. 3(A) and 3(B), they may also be formed as separate bodies.

[0040] The hardness of the material forming the metal rod 15 is preferably equal to or less than (more preferably less than) the hardness of the material forming the rotating shaft 10. This is to reduce wear of the rotating shaft 10 due to friction between the metal rod 15 and the rotating shaft 10.

[0041] <Configuration of Bearings 11, 12> Figure 4 is an enlarged cross-sectional view of the bearings 11, 12 and their surroundings. The bearing 11 has an inner ring 11a fixed to the rotating shaft 10, an outer ring 11b fitted into the annular portion 31a of the frame 31, and a plurality of rolling elements 11c provided between the inner ring 11a and the outer ring 11b. The rolling elements 11c are, for example, balls, but may also be rollers or the like. The outer ring 11b of the bearing 11 is in contact with the inner periphery of the annular portion 31a of the frame 31.

[0042] The bearing 12 has an inner ring 12a fixed to the rotating shaft 10, an outer ring 12b fitted into the first housing portion 32a of the bracket 32, and a plurality of rolling elements 12c provided between the inner ring 12a and the outer ring 12b. The rolling elements 12c are, for example, balls, but may also be rollers or the like. The outer ring 12b of the bearing 12 is in contact with the inner periphery of the first housing portion 32a of the bracket 32.

[0043] Additionally, a preload spring 13 (FIG. 1) serving as a preload member is disposed adjacent to the minor axis side of the bearing 12. The preload spring 13 applies a preload force F1 in the axial direction, more specifically, on the major axis side, to the outer ring 12b of the bearing 12. This preload force F1 causes the outer ring 12b of the bearing 12 to move toward the major axis relative to the inner ring 12a, and the rolling elements 12c come into contact with the inner ring 12a and the outer ring 12b.

[0044] The preload force F1 of the preload spring 13 biases the rotating shaft 10 toward the longitudinal axis via the inner ring 12a of the bearing 12. As a result, the inner ring 11a of the bearing 11 fixed to the rotating shaft 10 is also biased toward the longitudinal axis.

[0045] The inner diameter of the through hole (indicated by reference symbol 31e in FIG. 4) in the lid portion 31b is larger than the outer diameter of the inner ring 11a. The inner ring 11a fits into the through hole 31e, and the outer ring 11b abuts against the lid portion 31b and receives the reaction force of the preload force F1. As a result, the rolling elements 11c of the bearing 11 abut against the inner ring 11a and the outer ring 11b.

[0046] This reduces the clearance between the rolling element 11c of the bearing 11 and the inner ring 11a and the outer ring 11b, and also reduces the clearance between the rolling element 12c of the bearing 12 and the inner ring 12a and the outer ring 12b. As a result, the running trajectories of the rolling elements 11c and 12c become constant, and the rotation of the rolling elements 11c and 12c becomes stable.

[0047] Here, the contact portion 15a of the metal rod 15 is pressed against the rotating shaft 10 by the biasing portion 15b. The pressing force F2 with which the contact portion 15a is pressed against the rotating shaft 10 acts to move the inner ring 12a of the bearing 12 toward the longitudinal axis relative to the outer ring 12b. Therefore, the contact pressure between the rolling element 12c and the inner ring 12a and the outer ring 12b due to the preload force F1 of the preload spring 13 described above decreases.

[0048] On the other hand, since the rotating shaft 10 is urged toward the longitudinal axis by the pressing force F2, the inner ring 11a of the bearing 11 is urged toward the longitudinal axis by a resultant force F1+F2 of the preload force F1 and the pressing force F2. The outer ring 11b of the bearing 11 receives a reaction force of F1+F2 from the cover portion 31b of the frame 31.

[0049] If the pressing force F2 is large, the contact pressure between the rolling elements 11c of the bearing 11 and the inner and outer rings 11a and 11b increases, which may result in wear or mechanical damage. Also, the contact pressure between the rolling elements 12c of the bearing 12 and the inner and outer rings 12a and 12b decreases, which may create clearance and result in vibration.

[0050] Therefore, the pressing force F2 with which the contact portion 15a of the metal rod 15 is pressed against the rotating shaft 10 is set to be smaller than the preload force F1 that the preload spring 13 applies to the bearing 12. As an example, the pressing force F2 is set to 1 / 10 of the preload force F1. This reduces the clearance in the bearings 11 and 12, thereby suppressing vibrations and the like, and also suppressing wear and mechanical damage.

[0051] In the overall view of FIG. 1 and the like, the bearings 11 and 12 and the through-hole of the lid portion 31b (the through-hole 31e shown in FIG. 4) are shown in a simplified form.

[0052] <Mounting structure of metal rod 15> Figure 5 is a cross-sectional view showing a first example of the mounting structure of the metal rod 15 in the bracket 32. As described above, the bracket 32 ​​has the first accommodating portion 32a and the second accommodating portion 32b. The space S1 inside the first accommodating portion 32a and the space S2 inside the second accommodating portion 32b are continuous in the axial direction.

[0053] The first housing portion 32a has a space S1 inside thereof where a bearing 12 and a preload spring 13 are disposed. The second housing portion 32b has a space S2 inside thereof where a metal rod 15 is disposed. The first housing portion 32a is also referred to as a bearing housing portion, and the second housing portion 32b is also referred to as a metal rod housing portion.

[0054] The inner diameter Dm of the second housing portion 32b is smaller than the inner diameter Db of the first housing portion 32a. In other words, Dm<Db. This allows the bearing 12 and the metal rod 15 to be positioned so as not to interfere with each other.

[0055] As described above, the contact portion 15a of the metal rod 15 is in contact with the axial end surface of the rotating shaft 10. The biasing portion 15b of the metal rod 15 is in contact with the bottom portion 32d of the bracket 32. In other words, the metal rod 15 is sandwiched in the axial direction between the axial end surface of the rotating shaft 10 and the bottom portion 32d of the bracket 32.

[0056] A through hole 32h is formed in the bottom portion 32d of the bracket 32. The through hole 32h passes through the bottom portion 32d in the axial direction. The cross-sectional shape of the through hole 32h in a plane perpendicular to the axial direction is circular in this example, but is not limited to being circular.

[0057] The inner diameter Dh of the through hole 32h is smaller than the inner diameter Dm of the second housing portion 32b and also smaller than the maximum outer diameter Dw (FIGS. 3A and 3B) of the biasing portion 15b of the metal rod 15. That is, Dh<Dm and Dh<Dw are satisfied. This prevents the metal rod 15 from falling out of the through hole 32h. The inner diameter Dh of the through hole 32h is, for example, 5 mm.

[0058] A part (denoted by the symbol A) of the biasing portion 15b of the metal rod 15 is joined to the inner surface (including the upper surface of the bottom portion 32d) of the second housing portion 32b of the bracket 32. The joining is, for example, by welding.

[0059] 6A and 6B are schematic diagrams for explaining a method for welding the metal rod 15 to the bracket 32. As described above, both the metal rod 15 and the bracket 32 ​​are made of metal.

[0060] As shown in Figure 6 (A), a welding tool 81 such as a welding gun or welding torch is inserted into the second accommodating portion 32b through the through hole 32h, and a part of the biasing portion 15b of the metal rod 15 is welded to the inner surface of the second accommodating portion 32b of the bracket 32.

[0061] As a result, as shown schematically in Figure 6 (B), a part (indicated by the symbol W1) of the biasing portion 15b of the metal rod 15 and the corresponding inner surface of the second accommodating portion 32b of the bracket 32 ​​melt together and become one.

[0062] By welding a part of the biasing portion 15b of the metal rod 15 to the bracket 32, the metal rod 15 and the bracket 32 ​​can be handled as a single unit in the assembly process of the motor 1. Furthermore, welding can more reliably establish electrical continuity between the metal rod 15 and the bracket 32.

[0063] Fig. 7 is a cross-sectional view showing a second example of the mounting structure of the metal rod 15 in the bracket 32. In the example shown in Fig. 7, the end 15c of the biasing portion 15b of the metal rod 15 is pulled out from the through-hole 32h of the bracket 32. Furthermore, the end 15c pulled out from the through-hole 32h is welded to the outer surface 32e of the bottom portion 32d as shown by the symbol W2.

[0064] In this case, too, by welding a part of the biasing portion 15b of the metal rod 15 to the bracket 32, the metal rod 15 and the bracket 32 ​​can be handled as a single unit, and electrical continuity between the metal rod 15 and the bracket 32 ​​is more reliably established. Furthermore, since the welding is performed on the outer surface 32e of the bracket 32, the welding work is simplified.

[0065] Fig. 8 is a cross-sectional view showing a third example of the mounting structure of the metal rod 15 in the bracket 32. In the example shown in Fig. 8, similar to the example shown in Fig. 7, the end 15c of the biasing portion 15b of the metal rod 15 is pulled out to the outside through the through hole 32h of the bracket 32. Furthermore, a screw 36 is screwed into the through hole 32h of the bracket 32.

[0066] It is desirable to use a tapping screw as the screw 36. In this case, the screw 36 can be screwed into the through hole 32h while forming a thread groove on the inner surface of the through hole 32h. Note that the material and strength of the metal rod 15 are selected so that the metal rod 15 does not break when the screw 36 is screwed into the through hole 32h.

[0067] 8, a portion of the metal rod 15 is fixed to the through-hole 32h with a screw 36, which allows the metal rod 15 and the bracket 32 ​​to be handled as a single unit and also ensures electrical continuity between the metal rod 15 and the bracket 32. Furthermore, since welding is not required, the assembly process can be further simplified.

[0068] In the assembly process of the motor 1, the metal rod 15 is inserted into the second housing portion 32b of the bracket 32, and then a portion of the metal rod 15 is fixed to the second housing portion 32b of the bracket 32 ​​through the through-hole 32h. The fixing method is as described with reference to FIGS.

[0069] By fixing a portion of the metal rod 15 to the bracket 32, it becomes possible to handle the second housing portion 32b and the metal rod 15 as a single unit during the assembly process of the motor 1. Thereafter, the preload spring 13 and the bearing 12 are attached to the inside of the first housing portion 32a of the bracket 32.

[0070] Concurrently, the stator 22 is attached to the inside of the peripheral wall portion 31d of the frame 31 (FIG. 1). The rotating shaft 10, to which the rotor 21 and bearing 11 are attached, is inserted into the frame 31, and the bearing 11 is fitted inside the annular portion 31a of the frame 31.

[0071] Thereafter, the frame 31 and the bracket 32 ​​are combined together, and the bearing 12 is fitted onto the rotating shaft 10. In this way, the motor 1 is completed.

[0072] <Operation> In the motor 1, the stator core 22a and the windings 22b of the stator 22 are insulated by the insulating portion 22c (Fig. 2). When a voltage is applied to the windings 22b, the insulating portion 22c acts as a dielectric, and the stator core 22a and the windings 22b act as electrodes to form a capacitor. Therefore, a voltage is induced in the windings 22b in the stator core 22a, which is an electrical conductor.

[0073] When this voltage causes a potential difference between the inner rings 11a, 12a and the outer rings 11b, 12b of the bearings 11, 12, current flows inside each of the bearings 11, 12. As a result, the raceway surfaces of the inner rings 11a, 12a and the outer rings 11b, 12b are damaged, causing so-called electrolytic corrosion.

[0074] In the first embodiment, the metal rod 15 comes into contact with the rotating shaft 10, thereby establishing electrical continuity between the metal rod 15 and the rotating shaft 10. Furthermore, the rotating shaft 10 comes into contact with the inner rings 11a and 12a of the bearings 11 and 12 (FIG. 4), thereby establishing electrical continuity between the metal rod 15 and the inner rings 11a and 12a of the bearings 11 and 12.

[0075] Furthermore, the metal rod 15 is in contact with the conductive bracket 32, and the bracket 32 ​​is in contact with the conductive frame 31. The outer ring 11b of the bearing 11 is in contact with the frame 31, and the outer ring 12b of the bearing 12 is in contact with the bracket 32, so that the metal rod 15 and the outer rings 11b and 12b of the bearings 11 and 12 are electrically connected.

[0076] This reduces the potential difference between the inner ring 11a and outer ring 11b of the bearing 11 and the potential difference between the inner ring 12a and outer ring 12b of the bearing 12. Therefore, the current that would otherwise flow inside the bearings 11 and 12 can be directed from the metal rod 15 to the rotating shaft 10. As a result, no current flows inside the bearings 11 and 12, and the occurrence of electrolytic corrosion can be suppressed.

[0077] Furthermore, since the bracket 32 ​​has a through hole 32h, the metal rod 15 and the bracket 32 ​​can be fixed to each other by welding or the like via the through hole 32h. Therefore, in the assembly process of the motor 1, the metal rod 15 and the bracket 32 ​​can be handled as a single unit, simplifying the assembly process and reducing manufacturing costs. Furthermore, since the metal rod 15 and the bracket 32 ​​are reliably electrically connected, the effect of suppressing electrolytic corrosion of the bearings 11, 12 can be improved.

[0078] Since friction occurs due to contact between the metal rod 15 and the rotating shaft 10, it is desirable to supply a lubricant between the metal rod 15 and the rotating shaft 10. For example, it is desirable to apply a lubricant to the end face of the rotating shaft 10 that comes into contact with the metal rod 15.

[0079] Here, the through-hole 32h of the bracket 32 ​​is formed in the bottom 32d of the second housing portion 32b, but it is not limited to the bottom 32d and may be formed in, for example, a side portion of the second housing portion 32b. In other words, the through-hole 32h of the bracket 32 ​​only needs to be formed so as to communicate with the space S2 in which the metal rod 15 is housed.

[0080] Effects of the Embodiment As described above, the motor 1 of the first embodiment includes the rotor 21, the rotating shaft 10 attached to the rotor 21 and protruding from the rotor 21 to a first side (i.e., the long axis side) and a second side (i.e., the short axis side), with the protrusion on the first side being greater than the protrusion on the second side, the stator 22 facing the rotor 21 in the radial direction of the rotating shaft 10, a bearing 11 (i.e., the first bearing) supporting the rotating shaft 10 on the first side, a bearing 12 (i.e., the second bearing) supporting the rotating shaft 10 on the second side, a conductive bracket 32 ​​holding the bearing 12, and a metal rod 15 provided between the bracket 32 ​​and the end face of the second side of the rotating shaft 10. The metal rod 15 has a contact portion 15a that contacts the end face of the rotating shaft 10, and the contact portion 15a is movable in the axial direction. The bracket 32 ​​has a through hole 32h.

[0081] The metal rod 15 contacts the rotating shaft 10 and is electrically connected to the outer ring 12b of the bearing 12 via the bracket 32 ​​and the frame 31, thereby reducing the potential difference between the inner ring 12a and the outer ring 12b of the bearing 12 and suppressing the occurrence of electrolytic corrosion. Furthermore, since there is no need to use brushes, the motor 1 can be prevented from becoming larger and its manufacturing costs can be prevented from increasing.

[0082] Furthermore, since the bracket 32 ​​has the through-hole 32h, the metal rod 15 and the bracket 32 ​​can be fixed via the through-hole 32h by welding or the like. This makes it possible to handle the metal rod 15 and the bracket 32 ​​as a single unit, which simplifies the assembly process and reduces manufacturing costs.

[0083] Furthermore, since the through hole 32h is formed at the end of the bracket 32 ​​that is axially away from the rotating shaft 10 (i.e., the bottom 32d), a portion of the biasing portion 15b of the metal rod 15 can be easily fixed to the bracket 32.

[0084] In addition, by joining (specifically welding) the metal rod 15 to the bracket 32, the work of fixing the metal rod 15 to the bracket 32 ​​via the through hole 32h becomes easier, and it also becomes easier to ensure electrical continuity between the metal rod 15 and the bracket 32.

[0085] In addition, by fixing the metal rod 15 to the bracket 32 ​​with a screw 36, the metal rod 15 and the bracket 32 ​​can be easily fixed together with the screw 36 screwed into the through hole 32h, and electrical conductivity can be easily established between the metal rod 15 and the bracket 32.

[0086] Furthermore, by drawing a portion of the metal rod 15 out of the bracket 32 ​​through the through-hole 32h, the metal rod 15 can be fixed to the bracket 32 ​​more firmly.

[0087] Furthermore, when the inner diameter Dh of the through hole 32h and the inner diameter Dm of the second accommodating portion 32b of the bracket 32 ​​satisfy Dh<Dm, it is possible to prevent the metal rod 15 from falling out of the through hole 32h.

[0088] Furthermore, since the inner diameter Db of the first accommodating portion 32a of the bracket 32 ​​and the inner diameter Dm of the second accommodating portion 32b satisfy Dm < Db, the bearing 12 and the metal rod 15 can be positioned so as not to interfere with each other.

[0089] Furthermore, by making the hardness of the material of the metal rod 15 equal to or less than (more preferably, less than) the hardness of the material of the rotating shaft 10, wear of the rotating shaft 10 due to contact between the metal rod 15 and the rotating shaft 10 can be suppressed.

[0090] In addition, the motor 1 has a frame 31 that holds the bearing 11 and a bracket 32 ​​that holds the bearing 12, and the frame 31 and the bracket 32 ​​are electrically conductive, so that the metal rod 15, the frame 31 and the bracket 32 ​​can reduce the potential difference between the inner rings 11a, 12a and the outer rings 11b, 12b of the bearings 11, 12, thereby suppressing the occurrence of electrolytic corrosion.

[0091] Furthermore, since the preload spring 13 is provided between the bearing 12 and the bracket 32, the clearance between the bearings 11 and 12 can be reduced, and vibration can be suppressed.

[0092] In addition, since the preload spring 13 is arranged between the bearing 12 and the bracket 32 ​​in the axial direction, it becomes possible to attach the bearing 12, the preload spring 13 and the metal rod 15 to the bracket 32, thereby simplifying the configuration of the frame 31.

[0093] Furthermore, since the metal rod 15 has the biasing portion 15b that presses the contact portion 15a against the rotating shaft 10, the contact state between the contact portion 15a and the rotating shaft 10 can be maintained with a simple configuration.

[0094] 9 is a cross-sectional view showing a motor 1A of embodiment 2. The motor 1A of embodiment 2 has a conductive bracket 33 and an insulating cylindrical wall 34 instead of the conductive frame 31 (FIG. 1) of the motor 1 of embodiment 1.

[0095] The brackets 32 and 33 of the motor 1A are made of a conductor such as metal, and the cylindrical wall 34 of the motor 1A is made of an insulator such as resin. The brackets 32 and 33 and the cylindrical wall 34 form a housing.

[0096] The bracket 33 has an annular portion 33a, a lid portion 33b, and a plate-shaped portion 33c. The annular portion 33a, the lid portion 33b, and the plate-shaped portion 33c have the same shapes as the annular portion 31a, the lid portion 31b, and the plate-shaped portion 31c of the frame 31 in the first embodiment, respectively. The annular portion 33a of the bracket 33 holds the bearing 11. The bracket 33 is also referred to as a first bracket.

[0097] The cylindrical wall 34 is formed in a cylindrical shape centered on the central axis Ax and radially surrounds the motor unit 20. The stator 22 of the motor unit 20 is fitted to the inner periphery of the cylindrical wall 34. A bracket 33 is fixed to the end of the cylindrical wall 34 on the major axis side, and a bracket 32 ​​is fixed to the end of the cylindrical wall 34 on the minor axis side.

[0098] The bracket 32 ​​is configured in the same manner as the bracket 32 ​​of embodiment 1. The bearing 12 is disposed in the first housing portion 32a of the bracket 32, and the metal rod 15 is disposed in the second housing portion 32b. The configuration of the metal rod 15 is as described in embodiment 1. The bracket 32 ​​is also referred to as a second bracket.

[0099] A lead wire L1 is provided on the outer periphery of the cylindrical wall 34 to electrically connect the bracket 32 ​​and the bracket 33. One end of the lead wire L1 is fixed to the bracket 33 by a fixing part 41 such as a screw, and the other end of the lead wire L1 is fixed to the bracket 32 ​​by a fixing part 42 such as a screw. The fixing parts 41 and 42 are not limited to screws, and may be solder.

[0100] The metal rod 15 contacts the conductive bracket 32 ​​and is electrically connected to the outer ring 12b (FIG. 4) of the bearing 12 via the bracket 32. The bracket 32 ​​is electrically connected to the conductive bracket 33 via the lead wire L1.

[0101] The outer ring 11b of the bearing 11 contacts the bracket 33, and the outer ring 12b of the bearing 12 contacts the bracket 32, so that the metal rod 15 is electrically connected to the outer rings 11b and 12b (FIG. 4) of the bearings 11 and 12. The metal rod 15 also contacts the rotating shaft 10, and is electrically connected to the inner rings 11a and 12a (FIG. 4) via the rotating shaft 10.

[0102] This reduces the potential difference between the inner rings 11a, 12a and the outer rings 11b, 12b of the bearings 11, 12, and suppresses the occurrence of electrolytic corrosion in the bearings 11, 12.

[0103] Except for the above points, the motor 1A of the second embodiment is configured similarly to the motor 1 of the first embodiment.

[0104] As described above, in the motor 1A of the second embodiment, the metal rod 15, the brackets 32, 33, and the lead wire L1 reduce the potential difference between the inner rings 11 a, 12 a and the outer rings 11 b, 12 b of the bearings 11, 12, thereby suppressing the occurrence of electrolytic corrosion. Furthermore, because the motor section 20 is held by the cylindrical wall 34 made of resin or the like, vibration and noise of the motor 1 can be suppressed.

[0105] Embodiment 3. Figure 10 is a cross-sectional view showing a motor 1B of embodiment 3. Motor 1B of embodiment 3 differs from motor 1 of embodiment 1 (Figure 1) in that a seal member 50 is disposed on the metal rod 15 side of bearing 12 (lower side in the figure).

[0106] 11 is an enlarged view showing the seal member 50 and its surroundings. The seal member 50 is made of an elastically deformable material, such as rubber. The seal member 50 is disposed on the metal rod 15 side of the bearing 12. The seal member 50 is annular and has a thickness in the axial direction, centered on the central axis Ax.

[0107] The seal member 50 is fixed, for example, by adhesive or the like, to the end surface of the outer ring 12b of the bearing 12. It is desirable that the outer periphery of the seal member 50 contacts the inner periphery of the first accommodating portion 32a of the bracket 32. On the other hand, it is desirable that a small gap be provided between the inner periphery of the seal member 50 and the outer periphery of the rotating shaft 10.

[0108] When the rotating shaft 10 rotates, friction between the rotating shaft 10 and the metal rod 15 may generate wear particles. If the wear particles get into the inside of the bearing 12, they will get in between the inner ring 12a and the rolling elements 12c, or between the rolling elements 12c and the outer ring 12b, causing scratches on the rolling surfaces of the inner ring 12a or the outer ring 12b, which will cause noise.

[0109] In the third embodiment, the seal member 50 is provided on the metal rod 15 side of the bearing 12, which prevents wear debris from entering the bearing 12. This makes it possible to suppress the generation of abnormal noise caused by the intrusion of wear debris.

[0110] Although the axial position of the inner ring 12a and outer ring 12b of the bearing 12 may be shifted due to the biasing force of the preload spring 13 (see Figure 4), the sealing member 50 is deformable, and therefore the effect of preventing wear debris from entering the bearing 12 can be maintained.

[0111] Except for the above points, motor 1B of embodiment 3 is configured similarly to motor 1 of embodiment 1. Note that seal member 50 described in embodiment 3 may also be attached to motor 1A of embodiment 2 (FIG. 9).

[0112] As described above, the motor 1B of embodiment 3 has a sealing member 50 on the metal rod 15 side of the bearing 12, so that even if wear powder is generated due to friction between the metal rod 15 and the rotating shaft 10, the wear powder can be prevented from entering the bearing 12, thereby preventing noise from being generated.

[0113] 12 is a cross-sectional view showing a motor 1C according to embodiment 4. In the motors 1, 1A, and 1B according to embodiments 1 to 3, the preload spring 13 is provided on the short shaft side, but in the motor 1C according to embodiment 4, the preload spring 13 is provided on the long shaft side.

[0114] The motor 1C has a frame 31 on the long shaft side and a bracket 32 ​​on the short shaft side. The frame 31 has an annular portion 31a, a cover portion 31b, a plate-like portion 31c, and a peripheral wall portion 31d. The annular portion 31a is longer in the axial direction than the annular portion 31a of the first embodiment and accommodates the bearing 11 and the preload spring 13.

[0115] Inside the annular portion 31a of the frame 31, a preload spring 13 is arranged in a space S3 between the bearing 11 and the cover portion 31b in the axial direction.

[0116] The bracket 32 ​​has a first housing portion 32a, a second housing portion 32b, and a plate-shaped portion 32f. The first housing portion 32a of the bracket 32 ​​has an axial length shorter than that of the first housing portion 32a of the first embodiment, and houses only the bearing 12. The bearing 12 is held with one axial end face thereof abutting against a bottom portion 32c of the first housing portion 32a.

[0117] Except for the above points, motor 1C of embodiment 4 is configured similarly to motor 1 of embodiment 1. Note that in motor 1A of embodiment 2 (FIG. 9) or motor 1B of embodiment 3 (FIG. 10), preload spring 13 may be disposed on the long shaft side.

[0118] As described above, in the motor 1C of the fourth embodiment, the preload spring 13 is disposed on the long axis side, i.e., on the opposite side from the metal rod 15, so there is no interference between the preload spring 13 and the metal rod 15. Furthermore, the axial dimension of the bracket 32 ​​on the short axis side can be shortened.

[0119] Modifications. Modifications applicable to the first to fourth embodiments will be described. Fig. 13(A) is a schematic diagram showing the contact state between the contact portion 15a of the metal rod 15 and the rotating shaft 10 in Modification 1. As described in the first embodiment, the contact portion 15a of the metal rod 15 contacts the end face of the rotating shaft 10. Therefore, when the rotating shaft 10 rotates, the contact position between the rotating shaft 10 and the contact portion 15a of the metal rod 15 may not be stable.

[0120] For example, if the contact position of the contact portion 15a of the metal rod 15 deviates from the center of the rotating shaft 10 (i.e., on the central axis Ax), the metal rod 15 may swing in a circular motion and may come off the end face of the rotating shaft 10, resulting in vibration and noise, or deterioration of the metal rod 15 due to fatigue.

[0121] 13A, a recess 10c is provided on the end face of the rotating shaft 10. The recess 10c has, for example, a conical inclined surface that becomes deeper radially inward (i.e., closer to the central axis Ax). The deepest point (apex) 10d of the recess 10c is located on the central axis Ax.

[0122] The contact portion 15a of the metal rod 15 has a protrusion 15d. The protrusion 15d has a curved surface, such as a hemispherical surface.

[0123] In this way, the convex portion 15d of the contact portion 15a of the metal rod 15 comes into contact with the concave portion 10c of the rotating shaft 10, so that the contact position between them is guided onto the central axis Ax, thereby stabilizing the contact position between the contact portion 15a of the metal rod 15 and the rotating shaft 10, suppressing vibration and noise, and preventing the progression of deterioration due to fatigue.

[0124] Fig. 13(B) is a schematic diagram showing the contact state between the contact portion 15a of the metal rod 15 and the rotating shaft 10 in Modification 2. In the example shown in Fig. 13(B), a protrusion 10e is provided on the end surface of the rotating shaft 10. The protrusion 10e has, for example, a conical inclined surface that protrudes more radially inward (i.e., closer to the central axis Ax). The apex 10f of the protrusion 10e is located on the central axis Ax.

[0125] The contact portion 15 a of the metal rod 15 has a recess 15 e. The recess 15 e has, for example, a conical inclined surface that becomes deeper radially inward (i.e., closer to the central axis Ax). The angle formed between the inclined surface of the recess 15 e of the metal rod 15 and the central axis Ax is larger than the angle formed between the inclined surface of the protrusion 10 e of the rotating shaft 10 and the central axis Ax.

[0126] In this way, the recess 15e of the contact portion 15a of the metal rod 15 comes into contact with the protrusion 10e of the rotating shaft 10, so that the contact position between them is guided onto the central axis Ax, thereby stabilizing the contact position between the contact portion 15a of the metal rod 15 and the rotating shaft 10, suppressing vibration and noise, and preventing the progression of deterioration due to fatigue.

[0127] Fig. 14 is a cross-sectional view showing a motor 1D of Modification 3. The motor 1D shown in Fig. 14 differs from the motor 1 of Embodiment 1 (Fig. 1) in that the through-hole 32h of the bracket 32 ​​is closed with a sealing member 38.

[0128] As described in the first embodiment, when the metal rod 15 is welded to the inner surface of the bracket 32 ​​(see FIGS. 6A and 6B), the through hole 32h is not used after welding. Therefore, in the motor 1D of the third modification, after the metal rod 15 is welded to the inner surface of the bracket 32, the through hole 32h is closed with a sealing member 38.

[0129] The material of the sealing member 38 is, for example, resin, but is not limited to resin and may be any material that can close the through-hole 32 h. Alternatively, after welding a portion of the metal rod 15 to the inner surface of the bracket 32, a screw 36 ( FIG. 8 ) such as a tapping screw may be screwed into the through-hole 32 h.

[0130] By closing the through-hole 32h with the sealing member 38, there is an advantage in that it is possible to prevent foreign matter from entering the inside of the bracket 32 ​​through the through-hole 32h.

[0131] In the motors 1A, 1B, and 1C of the second to fourth embodiments, the through-hole 32h of the bracket 32 ​​may be closed with a sealing member .

[0132] In the metal rod 15 described in the first to fourth embodiments and the modified examples, the contact portion 15a and the biasing portion 15b are integrally formed. However, the contact portion 15a and the biasing portion 15b may be formed separately and fixed to each other.

[0133] Furthermore, although the bearings 11 and 12 described in the first to fourth embodiments and the modifications are ball bearings, they may be other types of bearings, such as roller bearings.

[0134] <Air Conditioning Apparatus> Next, an air conditioning apparatus to which the motors of the above-described embodiments can be applied will be described. Fig. 15(A) is a diagram showing the configuration of an air conditioning apparatus 100 to which the motor 1 of embodiment 1 is applied. The air conditioning apparatus 100 includes an outdoor unit 101 and an indoor unit 102. The outdoor unit 101 and the indoor unit 102 are connected by a refrigerant pipe 103.

[0135] The outdoor unit 101 includes a compressor 104, a condenser 105, and an outdoor blower 110. The outdoor blower 110 includes an impeller 111 and a motor 1 that drives the impeller 111. The motor 1 has the configuration described in the first embodiment.

[0136] The indoor unit 102 includes an evaporator 122 and an indoor blower 120. The indoor blower 120 has an impeller 121 and a motor 1M that drives the impeller 121.

[0137] 15(B) is a cross-sectional view of the outdoor unit 101. The motor 1 is supported by a motor support 107 arranged in a unit housing 106 of the outdoor unit 101. An impeller 111 is attached to the rotating shaft 10 of the motor 1 via a hub 112.

[0138] In the outdoor blower 110, an impeller 111 is rotated by a motor 1. During cooling operation of the air conditioner 100, the heat released when the refrigerant compressed by the compressor 104 is condensed in the condenser 105 is released to the outside by the air blown by the outdoor blower 110.

[0139] In the indoor fan 120 (FIG. 15A), an impeller 121 is rotated by a motor 1M. During cooling operation of the air conditioner 100, the air that has lost heat when the refrigerant evaporates in the evaporator 122 is blown into the room by the indoor fan 120.

[0140] As described in the first embodiment, electrolytic corrosion is prevented from occurring in the bearings 11 and 12 of the motor 1, which allows the outdoor blower 110 to operate stably for a long period of time. This improves the reliability of the air conditioning apparatus 100.

[0141] Here, the motor 1 of the first embodiment is used as the drive source for the outdoor blower 110, but the motors of the second to fourth embodiments or the modifications thereof may also be used.

[0142] Furthermore, the electric motors of the first to fourth embodiments and the modifications may be used as the motor 1M of the indoor blower 120, or may be used as the drive source for both the outdoor blower 110 and the indoor blower 120.

[0143] Although the preferred embodiments have been specifically described above, the present disclosure is not limited to the above-described embodiments, and various improvements and modifications can be made.

[0144] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1M Motor, 10 Rotating shaft, 11 Bearing, 11a Inner ring, 11b Outer ring, 11c Rolling element, 12 Bearing, 12a Inner ring, 12b Outer ring, 12c Rolling element, 13 Preload spring (preload member), 15 Metal rod, 15a Contact portion, 15b Urging portion (spring portion), 15c End portion, 20 Motor portion, 21 Rotor, 21a Rotor core, 21b Permanent magnet, 22 Stator, 22a Stator core, 22b Winding, 31 Frame (first bracket), 31a Annular portion, 31b Cover portion, 31c Plate-shaped portion, 31d Peripheral wall portion, 32 Bracket (second bracket), 32a First accommodating portion, 32b Second accommodating portion, 32c Bottom portion, 32d Bottom portion, 32f Plate-shaped portion, 32h Through hole, 33 Bracket, 34 Cylindrical wall (insulator), 36 Screw, 38 Sealing member, 41, 42 Fixing portion, 50 Sealing member, 81 Welding tool, 100 Air conditioning apparatus, 101 Outdoor unit, 102 Indoor unit, 110 Outdoor blower (blower), 111 Impeller, 120 Indoor blower (blower), 121 Impeller.

Claims

1. A motor comprising: a rotor; a rotating shaft fixed to the rotor, the rotating shaft protruding from the rotor to a first side and a second side in the axial direction of the rotating shaft, the protruding amount on the first side being greater than the protruding amount on the second side; a stator facing the rotor in the radial direction of the rotating shaft; a first bearing supporting the rotating shaft on the first side; a second bearing supporting the rotating shaft on the second side; a conductive bracket holding the second bearing; and a metal rod provided between the bracket and an end face of the second side of the rotating shaft, the metal rod having a contact portion that contacts the end face of the rotating shaft, the contact portion being axially movable, and the bracket having a through hole.

2. The motor according to claim 1, wherein the metal rod and the bracket are electrically connected.

3. The motor according to claim 1 or 2, wherein the through hole is formed at an end of the bracket that is farther from the rotating shaft in the axial direction.

4. The motor according to any one of claims 1 to 3, wherein the metal rod is joined to the bracket.

5. The motor according to claim 4, wherein the metal rod is welded to the bracket.

6. The motor according to claim 5, wherein a portion of the metal rod is pulled out to the outside of the bracket through the through hole and joined to the bracket at the outside of the bracket.

7. The motor according to any one of claims 1 to 3, wherein the metal rod is fixed to the bracket by a screw.

8. The motor according to claim 7, wherein a portion of the metal rod is pulled out to the outside of the bracket through the through hole and is sandwiched between the inner surface of the through hole and the screw.

9. The motor according to any one of claims 1 to 8, wherein the inner diameter Dh of the through hole and the inner diameter Dm of the metal rod accommodating portion of the bracket in which the metal rod is accommodated satisfy the relationship Dh<Dm.

10. A motor as claimed in any one of claims 1 to 9, wherein the bracket has a bearing accommodating section in which the second bearing is accommodated and a metal rod accommodating section in which the metal rod is accommodated, and the inner diameter Db of the bearing accommodating section and the inner diameter Dm of the metal rod accommodating section satisfy the relationship Dm < Db.

11. The motor according to any one of claims 1 to 10, wherein a seal member is disposed on the side of the second bearing that faces the metal rod in the axial direction.

12. The motor according to any one of claims 1 to 11, wherein the hardness of the material constituting the metal rod is lower than the hardness of the material constituting the rotating shaft.

13. The motor according to any one of claims 1 to 12, wherein one of the metal rod and the end face of the rotating shaft has a recess and the other has a protrusion, and the recess and the protrusion come into contact with each other.

14. The motor according to claim 13, wherein the recess has an inclined surface that becomes deeper toward the inside in the radial direction.

15. The motor according to any one of claims 1 to 14, wherein the bracket is a second bracket, and further comprising a conductive first bearing that supports the rotating shaft on the first side, and a conductive first bracket that holds the first bearing.

16. The motor according to claim 15, wherein a preload spring is disposed between the second bearing and the second bracket in the axial direction.

17. The motor according to claim 15, wherein a preload spring is disposed between the first bearing and the first bracket in the axial direction.

18. The motor according to any one of claims 15 to 17, wherein the first bracket and the second bracket are electrically connected.

19. The motor according to claim 18, wherein an insulator is disposed between the first bracket and the second bracket, and the first bracket and the second bracket are electrically connected by a lead wire.

20. A blower comprising a motor according to any one of claims 1 to 19 and an impeller attached to the rotating shaft of the motor.

21. An air conditioning apparatus comprising an outdoor unit and an indoor unit, wherein at least one of the outdoor unit and the indoor unit has the blower according to claim 20.

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