motor

Abstract

To provide a motor which can inhibit reduction of a life.SOLUTION: A motor 1 includes: a shaft 277; a first bearing 221 disposed at one axial side of the shaft 277; a second bearing 222 disposed at the other axial side of the shaft 277; and a bearing housing 207 serving as a holding member which holds the first bearing 221 and the second bearing 222. In a radial direction, a distance between the first bearing 221 and the holding member is smaller than a distance between the second bearing 222 and the bearing housing 207.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] Conventionally, a fan motor having a plurality of blades attached to the outside of a drive unit is known. The drive unit of such a fan motor may include, in an inner portion, a bearing device having a shaft, a pair of bearings attached to the shaft, and a bearing holder that supports the pair of bearings from the radially outer side (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the manufacture of such a conventional bearing device, a pair of bearings are liable to be damaged, and as a result, the life of the motor tends to be shortened.

[0005] Therefore, one of the problems of the present invention is to provide a motor in which a reduction in life can be suppressed.

Means for Solving the Problems

[0006] The above problems are solved by the following present invention. That is, the motor of the present invention includes a shaft, a first bearing disposed on one axial side of the shaft, a second bearing disposed on the other axial side of the shaft, and a holding member that holds the first bearing and the second bearing, and in the radial direction, the distance between the first bearing and the holding member is smaller than the distance between the second bearing and the holding member.

Brief Description of the Drawings

[0007] [Figure 1] This is a perspective view showing the overall configuration of a motor according to an embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view along the axis X of the motor shaft. [Figure 3] This is a simplified and enlarged view of the bearing device shown in Figure 2. [Figure 4] This figure shows the initial steps in the manufacturing process of the bearing device shown in Figure 3. [Figure 5] This figure shows the intermediate steps in the manufacturing process of the bearing device shown in Figure 3. [Figure 6] This figure shows the final stage of the manufacturing process for the bearing device shown in Figure 3. [Figure 7] This figure shows a simplified representation of the retaining member in a modified example of the bearing device shown in Figure 3. [Modes for carrying out the invention]

[0008] The following examples illustrate embodiments of the motor according to the present invention, along with the accompanying drawings. Note that, in order to facilitate understanding, the dimensions of each component in the accompanying drawings may be exaggerated or reduced, and the configuration may be simplified.

[0009] Figure 1 is a perspective view showing the overall configuration of the motor according to the embodiment, and Figure 2 is a cross-sectional view of the motor shown in Figure 1 along the direction of axis X.

[0010] The motor 1 according to this embodiment is configured as an axial flow fan motor and functions as an axial flow blower that blows air in the direction of axis X. As shown in Figures 1 and 2, the motor 1 mainly comprises a casing 200, an impeller 210, and a drive unit 250.

[0011] First, let me explain casing 200.

[0012] The casing 200 has a cylindrical shape that is approximately square in plan view, and the internal space of the casing 200 is a wind tunnel in which air flows from the upper end (the upper end in the direction of axis X (arrow a direction)) to the lower end (the lower end in the direction of axis X (arrow b direction)). Specifically, an air intake port 201 for drawing air into the internal space is formed at the upper end of the casing 200, and an exhaust port for releasing air is formed at the lower end of the casing 200. The impeller 210 and the drive unit 250, etc., are housed in the internal space of this casing 200.

[0013] The casing 200 has side walls 204, a base portion 205, and fixed wings 206.

[0014] The side wall 204 surrounds the impeller 210 from the radial direction perpendicular to the axis X (direction of arrow cd) and is connected to the upper end. The side wall 204 has a cylindrical shape centered on axis X and has an inner diameter that does not come into contact with the outer peripheral ends of the impeller 210 blades 212, which will be described later. That is, a predetermined gap is formed between the outer peripheral ends of the impeller 210 blades 212 and the inner peripheral surface of the side wall 204. The side wall 204 also functions as a guard portion that protects the impeller 210.

[0015] The fixed wing 206 consists of multiple stationary vanes, and the side wall 204 and the base portion 205 are connected radially by this fixed wing 206.

[0016] The base portion 205 includes a disc-shaped lower end portion 205a which is the lower end of the casing 200, a cylindrical outer wall 205b which extends upward along the axis X for a predetermined length from the outer circumference end of the lower end portion 205a, and a boss portion 205c which protrudes upward along the axis X for a predetermined length from the inner circumference end of the lower end portion 205a.

[0017] On the outer peripheral surface of the outer peripheral wall 205b, a fixed wing 206 is integrally formed. That is, the outer peripheral wall 205b is supported by the side wall 204 of the casing 200 via the fixed wing 206. An inner bearing housing 207 described later is attached to the inner peripheral surface of the boss portion 205c in the base portion 205. As will be described later, the bearing housing 207 is a part of the bearing device 290 of the drive unit 250.

[0018] The side wall 204, the base portion 205, and the fixed wing 206 of the casing 200 may be integrally formed by injection molding of a synthetic resin (for example, polybutylene terephthalate resin (including glass fiber)). Further, instead of the fixed wing 206 connecting the side wall 204 and the base portion 205, a plurality of spokes made of rod-shaped portions may be used.

[0019] Note that the casing 200 of the present embodiment is provided with four upper flange portions 202 at the corner portions of the upper end and four lower flange portions 203 at the corner portions of the lower end. In the present embodiment, each of the upper flange portions 202 and each of the lower flange portions 203 are integrally formed with the side wall 204. Through holes are provided in each of these upper flange portions 202 and lower flange portions 203, and bolts (not shown) for attaching to a predetermined device or housing are inserted through these through holes.

[0020] Next, the impeller 210 will be described.

[0021] As shown in FIG. 2, the impeller 210 includes a hub 211 having a bottomed substantially inverted U-shaped cross-sectional cup shape, and a plurality of blades 212 provided along the circumferential direction on the outer peripheral surface of the hub 211. The hub 211 and the plurality of blades 212 may be integrally formed by injection molding of a synthetic resin (for example, polybutylene terephthalate resin (including glass fiber)).

[0022] The hub 211 is bonded to the upper outer circumferential surface of the rotor yoke 271 of the drive unit 250, which will be described later, by adhesive. However, this is not the only option; the rotor yoke 271 may be inserted into the hub 211, and the inner circumferential surface of the hub 211 and the outer circumferential surface of the rotor yoke 271 may be integrally formed. Thus, in this embodiment, the hub 211 is integrally formed with the rotor yoke 271. The hub 211 also covers the upper end of the shaft 277, preventing foreign matter from entering from the outside. In this embodiment, in the direction of axis X, a coil spring 223 is positioned between the hub 211 and the first bearing 221, which will be described later, to apply preload to the first bearing 221.

[0023] The multiple blades 212 have generally the same shape and are arranged at roughly equal intervals in the circumferential direction of the hub 211.

[0024] Next, we will explain the drive unit 250.

[0025] As shown in Figure 2, the drive unit 250 mainly comprises a stator unit 260, a rotor unit 270, and a bearing device 290.

[0026] The bearing device 290 of the drive unit 250 is located on the innermost side of the drive unit 250. Figure 3 is a simplified and enlarged view of the bearing device 290, and is a cross-sectional view of the bearing device 290 along the direction of axis X. As shown in Figures 2 and 3, the bearing device 290 mainly comprises a shaft 277, a coil spring 209, a first bearing 221, a second bearing 222, and a bearing housing 207.

[0027] The shaft 277 of the bearing device 290 is located at the center of the motor 1 and has the aforementioned axis X as its central axis. The shaft 277 is press-fitted into the bush 273 of the rotor section 270, which will be described later, and extends along the direction of axis X from near the upper end to near the lower end of the motor 1.

[0028] The first bearing 221 and the second bearing 222 of the bearing device 290 have generally the same configuration and dimensions, and are ball bearings including an inner ring IR, an outer ring OR, and a plurality of balls BA provided between the inner ring IR and the outer ring OR. The first bearing 221 is provided above the second bearing 222, and the second bearing 222 is provided below the first bearing 221. The inner ring IR of the first bearing 221 and the second bearing 222 are press-fitted onto the shaft 277. Note that the first bearing 221 and the second bearing 222 are not limited to ball bearings.

[0029] Thus, the first bearing 221 supports the upper portion of the shaft 277 in the direction of axis X so that the shaft 277 can rotate, and the second bearing 222 supports the lower portion of the shaft 277 in the direction of axis X so that the shaft 277 can rotate. In other words, the shaft 277 is rotatably supported relative to the stator portion 260 by the first bearing 221 and the second bearing 222.

[0030] The coil spring 209 of the bearing device 290 is positioned between the first bearing 221 and the second bearing 222, and applies preload to the first bearing 221 and the second bearing 222.

[0031] The bearing housing 207 of the bearing device 290 is made of a hollow cylindrical metal material and is press-fitted at its lower end into the boss portion 205c of the casing 200. In this way, the bearing housing 207 is supported by the casing 200 and extends in the direction of axis X. In this embodiment, the bearing housing 207 is press-fitted into the boss portion 205c. However, it is not limited to this, and the bearing housing 207 may be formed integrally with the base portion 205 while inserted into the boss portion 205c.

[0032] As shown in Figure 3, the inner circumferential surface 207i of the bearing housing 207 is not flush with the surface, and at least the portion 207f of the inner circumferential surface 207i facing the first bearing 221 protrudes radially inward (radial direction d side). Therefore, the bearing housing 207 is configured such that, in the radial direction, the width W1 of the surface of the bearing housing 207 facing the first bearing 221 is greater than the width W2 of the surface of the bearing housing 207 facing the second bearing 222. In this embodiment, in a cross-section along the direction of axis X, the inner circumferential surface 207i of the bearing housing 207 consists of a lower surface 207d extending along the direction of axis X from the lower end of the inner circumferential surface 207i to approximately half the height of the inner circumferential surface 207i, a stepped surface 207e extending radially inward from the upper end of the lower surface 207d, and an upper surface 207u extending along the direction of axis X from the radially inward end of the stepped surface 207e to the upper end of the inner circumferential surface 207i. The upper surface 207u includes a portion 207f facing the first bearing 221, and the lower surface 207d includes a portion 207s facing the second bearing 222.

[0033] Incidentally, if the inner circumferential surface 207i were flush, the distance between the outer circumferential surface of the outer ring OR of the first bearing 221 and the inner circumferential surface 207i of the bearing housing 207 would be equal in the radial direction to the distance between the outer circumferential surface of the outer ring OR of the second bearing 222 and the inner circumferential surface 207i of the bearing housing 207. However, in this embodiment, as described above, at least the portion 207f of the inner circumferential surface 207i facing the first bearing 221 protrudes radially inward, so in the radial direction, the distance between the outer circumferential surface of the outer ring OR of the first bearing 221 and the inner circumferential surface 207i of the bearing housing 207 is smaller than the distance between the outer circumferential surface of the outer ring OR of the second bearing 222 and the inner circumferential surface 207i of the bearing housing 207.

[0034] Adhesive 282 is filled in the gap between the outer surface of the outer ring OR of the second bearing 222 and the inner surface 207i of the bearing housing 207, and the outer ring OR of the second bearing 222 is bonded to the inner surface 207i of the bearing housing 207 via this adhesive 282. In this way, in the motor 1, the bearing housing 207 and the outer ring OR of the second bearing 222 are bonded to each other such that the angle between them is substantially 90°, and the inner ring IR of the second bearing 222 is press-fitted onto the shaft 277 as described above, so that the second bearing 222 is supported on the shaft 277 at a substantially 90° angle to the shaft 277. That is, in the motor 1, the second bearing 222 is mounted substantially perpendicular to the shaft 277 and the bearing housing 207, which extend in the direction of axis X.

[0035] Adhesive 281 fills the gap between the outer circumferential surface of the outer ring OR of the first bearing 221 and the inner circumferential surface 207i of the bearing housing 207. Adhesive 281 may be made of the same material as adhesive 282, or it may be made of a different material. The adhesive 281 protrudes onto at least one of the upper and lower sides of the first bearing 221, due to reasons such as the distance between the outer circumferential surface of the outer ring OR of the first bearing 221 and the inner circumferential surface 207i of the bearing housing 207 being smaller in the radial direction than the distance between the outer circumferential surface of the outer ring OR of the second bearing 222 and the inner circumferential surface 207i of the bearing housing 207. In this embodiment, the adhesive 281 includes a first portion 281u that protrudes onto the upper side of the first bearing 221 and a second portion 281d that protrudes onto the lower side of the first bearing 221. The outer ring OR of the first bearing 221 is bonded to the inner circumferential surface 207i of the bearing housing 207 by such adhesive 281. Thus, in motor 1, the bearing housing 207 and the outer ring OR of the first bearing 221 are bonded to each other such that the angle between them is substantially 90°, and the inner ring IR of the first bearing 221 is press-fitted onto the shaft 277 as described above, so that the first bearing 221 is supported on the shaft 277 at a substantially 90° angle to the shaft 277. In other words, in motor 1, the first bearing 221 is mounted substantially perpendicular to the shaft 277 and the bearing housing 207, which extend in the direction of axis X.

[0036] In this embodiment, as described above, the first bearing 221 and the bearing housing 207 are fixed together with adhesive, and the second bearing 222 and the bearing housing 207 are fixed together with adhesive. However, the invention is not limited to this, and at least one of the first bearing 221 and the second bearing 222 may be fixed to the bearing housing by other methods, such as fixing them via an elastic member or a member having viscosity or adhesive properties.

[0037] Thus, the bearing housing 207 functions as a retaining member capable of holding the first bearing 221 and the second bearing 222, respectively, substantially perpendicular to the shaft 277.

[0038] As shown in Figure 2, the stator section 260 of the drive unit 250 mainly comprises a stator core 261, an insulator 262, and a coil 263.

[0039] In this embodiment, the stator core 261 of the stator section 260 is formed by a laminate of multiple cores made of electromagnetic steel sheets made of soft magnetic material. In this embodiment, a circular opening is formed on the inner circumferential surface of the stator core 261, and the outer circumferential surface of the bearing housing 207 is fitted into this opening. In this way, the stator core 261 is attached to the bearing housing 207 and is located radially outward (radial direction c side) relative to the bearing housing 207. Note that adhesive may also be used to fix the stator core 261 to the bearing housing 207.

[0040] The insulator 262 of the stator section 260 is made of an insulating material and is attached to the stator core 261, covering the stator core 261. The coil 263 of the stator section 260 is wound around the stator core 261 via the insulator 262. In this way, since the coil 263 is wound around the stator core 261 via the insulator 262, the stator core 261 and the coil 263 are insulated from each other by the insulator 262.

[0041] As shown in Figure 2, the rotor section 270 of the drive unit 250 mainly comprises a rotor yoke 271, a magnet 272, and a bush 273.

[0042] The rotor yoke 271 has a hollow cylindrical shape and is made of, for example, a soft magnetic material. The rotor yoke 271 is positioned radially outward from the coil 263 of the stator section 260. The magnet 272 is formed in an annular shape and is positioned on the inner circumferential surface of the rotor yoke 271. That is, the magnet 272 is positioned radially between the coil 263 of the stator section 260, which is located on the inside, and the rotor yoke 271, which is located on the outside, and faces the coil 263. The rotor yoke 271 and the magnet 272 are each positioned coaxially with the shaft 277.

[0043] The bush 273 is made of, for example, a soft magnetic material and is connected to the upper end of the rotor yoke 271, covering the upper part of the rotor yoke 271. For example, the bush 273 may be attached to the rotor yoke 271 by integrally fixing the inner circumference of the rotor yoke 271 to the outer circumference of the bush 273 by crimping. A recess is formed in the center of the bush 273, into which the shaft 277 is press-fitted.

[0044] In this embodiment, the rotor yoke 271 and the magnet 272 are integrated via a hub 211, and the shaft 277 is integrated with the hub 211 via a bush 273. Thus, in this embodiment, the rotor yoke 271 of the rotor section 270 is attached integrally with the impeller 210. Therefore, in the motor 1 of this embodiment, when the rotor yoke 271 rotates around the shaft 277 due to the electromagnetic action between the coil 263 of the stator section 260 and the magnet 272 of the rotor section 270, the impeller 210 rotates together with the rotor yoke 271, and it operates as an outer rotor type motor. That is, the rotor section 270 functions as a rotating body, integrated with the blades 212 by the hub 211 which is attached integrally with the rotor yoke 271.

[0045] As described above, the motor 1 comprises a shaft 277, a first bearing 221 positioned on one side (upper side) of the shaft 277 in the direction of axis X, a second bearing 222 positioned on the other side (lower side) of the shaft 277 in the direction of axis X, and a bearing housing 207 (holding member) that holds the first bearing 221 and the second bearing 222. In the radial direction, the distance between the first bearing 221 and the bearing housing 207 is smaller than the distance between the second bearing 222 and the bearing housing 207.

[0046] In this motor 1, the distance between the first bearing 221 and the bearing housing 207 is configured to be smaller than the distance between the second bearing 222 and the bearing housing 207. Therefore, as will be explained in the manufacturing method of the bearing device 290 described later, the first bearing 221 is prevented from being mounted at an angle with respect to the shaft 277 (i.e., the angle between the shaft 277 and the first bearing 221 is not 90°) when the bearing device 290 is manufactured. As a result, during the operation of the motor 1, the load on the first bearing 221 due to the tilt of the first bearing 221 with respect to the shaft 277 is prevented, and consequently, damage to the first bearing 221 is prevented. And because damage to the first bearing 221 is prevented, the tilting of the shaft 277 that would result from damage to the first bearing 221 is prevented. As a result, damage to the second bearing 222 caused by the tilting of the shaft 277 is further prevented. In this way, in motor 1, damage to the first bearing 221 and the second bearing 222 is suppressed, and thus the reduction in the motor's lifespan can be suppressed.

[0047] Next, an example of a manufacturing method for the bearing device 290 described above will be explained with reference to Figures 4 to 6. Note that Figures 4 to 6 are cross-sectional views similar to those in Figure 3, but the hatching has been omitted for convenience.

[0048] First, as shown in Figure 4, the first jig 310, the second jig 320, and the third jig 330 are prepared, and the first step is performed.

[0049] The first jig 310 has a generally cylindrical shape that is flattened horizontally. The first jig 310 consists of a first rectangular part 311 with a relatively large cross-sectional shape along the vertical direction, and a second rectangular part 312 with a smaller cross-sectional shape along the vertical direction than the first part 311. The first part 311 and the second part 312 are integrated, and the second part 312 is located above the first part 311. With this configuration, the outer edge of the first jig 310 has a corner 313 where the upper surface 311u of the first part 311 and the side surface 312s of the second part 312 form a 90° angle. The diameter of the second part 312 is substantially the same as the diameter of the lower surface 207d of the inner circumferential surface 207i of the bearing housing 207, and is larger by a predetermined length than the outer diameter of the second bearing 222 (i.e., the diameter of the outer ring OR of the second bearing 222).

[0050] The second jig 320 has a generally cylindrical shape that is elongated vertically, and a protrusion 321 having a cylindrical and ring-shaped outer shape protrudes downward from the outer edge of the lower end surface of the second jig 320. The diameter of the second jig 320 is slightly smaller than the diameter of the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207, and is approximately equal to the outer diameter of the second bearing 222. The third jig 330 has a cylindrical and ring-shaped outer shape, and the inner diameter of the third jig 330 is slightly larger than the diameter of the second jig 320. Therefore, the second jig 320 can pass through the space inside the third jig 330.

[0051] In the first step, after placing the first jig 310 on a horizontal surface, the second bearing 222, on which adhesive 282 has been applied to its outer surface (outer surface of the outer ring OR), is placed on the upper surface 312u of the second part 312 of the first jig 310. At this time, the center of the upper surface 312u of the second part 312 is aligned with the center of the second bearing 222. Next, while maintaining this state, the protruding part 321 of the second jig 320 is brought into contact with the second bearing 222 so that the outer surface of the protruding part 321 of the second jig 320 is approximately flush with the outer surface of the second bearing 222. In this way, the second bearing 222 is held vertically from above and below by the first jig 310 and the second jig 320. Next, the lower end of the bearing housing 207 is fitted into the corner 313 of the first jig 310, and then the third jig 330 is fitted onto the outside of the second jig 320 from above, so that the lower surface 330d of the third jig 330 abuts against the upper surface of the bearing housing 207. In this way, the bearing housing 207 is held vertically from above and below by the first jig 310 and the third jig 330, and the bearing housing 207 and the second bearing 222 are held at an angle of 90°. This state is maintained until the adhesive 282 hardens. As a result, a first assembly 291 (see Figure 5) is obtained in which the bearing housing 207 and the second bearing 222 are bonded by the adhesive 282 at an angle of substantially 90°. Thus, the first step is to fix the second bearing 222 perpendicular to the bearing housing 207, which is the holding member.

[0052] As described above, the diameter of the second portion 312 of the first jig 310 is larger than the outer diameter of the second bearing 222 by a predetermined length. Therefore, in the first step, a certain amount of radial space is formed between the lower surface 207d of the inner circumferential surface 207i of the bearing housing 207 and the outer circumferential surface of the second bearing 222. As a result, the adhesive 282 filling this space is not easily compressed by the inner circumferential surface 207i of the bearing housing 207 and the outer circumferential surface of the second bearing 222, and does not protrude above or below the second bearing 222, or if it does protrude, the amount is negligibly small.

[0053] Next, after removing the first jig 310, the second jig 320, and the third jig 330, the second step is performed.

[0054] In the second step, as shown in Figure 5, the second bearing 222 of the first assembly 291 is supported from below using the fourth jig 340. The fourth jig 340 has a generally cylindrical shape that is flattened horizontally. The fourth jig 340 consists of a first rectangular part 341 with a relatively large cross-sectional shape along the vertical direction, and a second rectangular part 342 with a smaller cross-sectional shape along the vertical direction than the first part 341. The first part 341 and the second part 342 are integrated, and the second part 342 is located above the first part 341. The vertical height of the second part 342 is equal to the vertical length from the lower end of the second bearing 222 in the first assembly 291 to the lower end of the bearing housing 207. The outer diameter of the first part 341 is larger than the outer diameter of the bearing housing 207. The outer diameter of the second part is larger than the outer diameter of the inner ring IR of the second bearing 222 and smaller than the inner diameter of the outer ring OR. A through hole 340H is formed in the horizontal center of the second portion 342, penetrating the second portion 342 vertically. This through hole 340H is formed to have a diameter slightly larger than that of the shaft 277 and extends to the horizontal center of the first portion 341, partway along the vertical direction of the first portion 341.

[0055] In the second step, after placing the fourth jig 340 as described above on a horizontal surface, the second bearing 222 of the first assembly 291 is placed on the upper surface of the second part 342 of the fourth jig 340 such that the insertion hole 340H of the fourth jig 340 communicates with the through hole of the second bearing 222 defined by the inner circumferential surface of the second bearing 222 (the inner circumferential surface of the inner ring IR). As a result, the inner ring IR of the second bearing 222 is supported from below by the second part 342 of the fourth jig 340, and the bearing housing 207 of the first assembly 291 is supported from below by the first part 341 of the fourth jig 340.

[0056] Next, in the second step, the shaft 277 is inserted from above into the internal space of the bearing housing 207 of the first assembly 291, and this shaft 277 is press-fitted into the through hole of the second bearing 222. The shaft 277, press-fitted into the through hole of the second bearing 222, reaches the lower end of the insertion hole 340H of the fourth jig 340. In this way, the inner ring IR of the second bearing 222 is supported on the shaft 277 at a substantially 90° angle with respect to the shaft 277. That is, this second step yields the second assembly 292 in which the second bearing 222 is mounted substantially perpendicular to the shaft 277 and the bearing housing 207, respectively, which extend in the direction of axis X.

[0057] Next, the third step is performed. As shown in Figure 5, in this third step, the coil spring 209 described above is inserted into the space between the shaft 277 of the second assembly 292 and the bearing housing 207. The lower end of the coil spring 209 is supported by the second bearing 222. In this way, the third assembly 293, consisting of the second assembly 292 and the coil spring 209, is obtained. In the vertical direction, the position of the upper end of the coil spring 209 of the third assembly 293 corresponds to the position of the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207.

[0058] Next, the fourth step is performed. As shown in Figure 5, in this fourth step, the first bearing 221 is press-fitted onto the shaft 277 of the third assembly 293 from above using the fifth jig 350. Adhesive 281 is applied to the outer circumferential surface of the first bearing 221 (outer circumferential surface of the outer ring OR) in the fourth step. The fifth jig 350 has a generally cylindrical shape. The fifth jig 350 consists of a first rectangular part 351 with a relatively large cross-sectional shape along the vertical direction, and a second rectangular part 352 with a smaller cross-sectional shape along the vertical direction than the first part 351. The first part 351 and the second part 352 are integrated, and the second part 352 is located below the first part 351. The outer diameter of the second part 352 is larger than the outer diameter of the inner ring IR of the first bearing 221 and smaller than the inner diameter of the outer ring OR. A through hole 350H is formed in the horizontal center of the second portion 352, penetrating the second portion 352 vertically. This through hole 350H is formed to have a diameter slightly larger than that of the shaft 277 and extends to the horizontal center of the first portion 351, at a point midway along the vertical direction of the first portion 351.

[0059] In the fourth step, the upper end of the shaft 277 of the third assembly 293 is inserted into the through hole of the first bearing 221, which is defined by the inner circumferential surface of the first bearing 221 (the inner circumferential surface of the inner ring IR). Then, the lower surface of the second portion 352 of the fifth jig 350 is brought into contact with the inner ring IR of the first bearing 221. The shaft 277 is then inserted through the insertion hole 350H of the fifth jig 350, while the fifth jig 350 is pushed down. By pushing down the fifth jig 350 in this way while inserting the shaft 277 through the insertion hole 350H, the fifth jig 350 is guided vertically downward, and the inner ring IR of the first bearing 221 is pushed down by the fifth jig 350. In this way, the first bearing 221 is press-fitted to the position of the upper end of the coil spring 209 of the third assembly 293. As described above, in the vertical direction, the upper end of the coil spring 209 corresponds to the position of the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207. As a result, the inner ring IR of the first bearing 221 is supported on the shaft 277 at a substantially 90° angle with respect to the shaft 277. That is, the fourth step is to attach the inner ring IR of the first bearing 221 to the shaft 277 at a substantially 90° angle with respect to the shaft 277 to obtain the fourth assembly 294. In this fourth assembly 294, the adhesive 281 is in an unhardened state.

[0060] As described above, the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207 protrudes radially inward more than the lower surface 207d. Therefore, the distance between the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207 and the outer surface of the first bearing 221 press-fitted onto the shaft 277 is narrower than the distance between the lower surface 207d of the inner circumferential surface 207i of the bearing housing 207 and the outer surface of the second bearing 222 press-fitted onto the shaft 277. Consequently, when the first bearing 221 is press-fitted, even if the outer ring OR of the first bearing 221 tries to tilt relative to the shaft 277 or bearing housing 207 due to the elastic force of the coil spring 209, the outer ring OR immediately contacts the upper surface 207u, suppressing such tilting. As a result, at the end of the fourth step, deviations from 90° in the angles between the outer ring OR of the first bearing 221 and the shaft 277 and the bearing housing 207 are suppressed.

[0061] Incidentally, the gap between the upper surface 207u and the outer surface of the first bearing 221 is narrower than the gap between the lower surface 207d and the outer surface of the second bearing 222. Therefore, in the fourth step, the adhesive 281 applied to the outer surface of the first bearing 221 does not fit completely into the gap between the upper surface 207u and the outer surface of the first bearing 221, and protrudes outwards on at least one of the upper and lower sides of the first bearing 221. For convenience, the illustration of the adhesive 281 protruding outwards on the upper and lower sides of the first bearing 221 is omitted in Figure 5.

[0062] Next, after removing the fourth jig 340 and the fifth jig 350, the fifth step is performed. As shown in Figure 6, the sixth jig 360 and the seventh jig 370 are used in this fifth step.

[0063] The sixth jig 360 has a generally cylindrical shape that is flattened horizontally. The sixth jig 360 has a first part 361 which has a rectangular shape when viewed in cross-section along the vertical direction, and a second part 362 which is cylindrical and ring-shaped and protrudes upward from the upper surface of the first part 361. The outer diameter of the second part 362 of the sixth jig 360 is smaller than the diameter of the lower surface 207d on the inner circumferential surface 207i of the bearing housing 207, and the inner diameter of the second part 362 is approximately equal to the inner diameter of the outer ring OR of the second bearing 222. In the horizontal center of the first part 361 of the sixth jig 360, there is an insertion hole 360H which is slightly larger than the diameter of the shaft 277.

[0064] The seventh jig 370 has a generally cylindrical shape that is flattened horizontally. The seventh jig 370 has a first part 371 which has a rectangular cross-sectional shape along the vertical direction, and a second part 372 which is cylindrical and ring-shaped and protrudes downward from the lower surface of the first part 371. The outer diameter of the second part 372 of the seventh jig 370 is smaller than the diameter of the upper surface 207u on the inner circumferential surface 207i of the bearing housing 207. Also, the inner diameter of the second part 372 is smaller than the inner diameter of the outer ring OR of the first bearing 221, and larger than the outer diameter of the inner ring IR. In the horizontal center of the first part 371 of the seventh jig 370, there is an insertion hole 370H which is slightly larger than the diameter of the shaft 277.

[0065] In the fifth step, first, the sixth jig 360 is placed on a horizontal surface, and then the shaft 277 of the fourth assembly 294 is inserted into the through hole 360H of the sixth jig 360. This causes the outer ring OR of the second bearing 222 of the fourth assembly 294 to be supported from below by the sixth jig 360. Next, the seventh jig 370 is pushed down while the shaft 277 is inserted into the through hole 370H of the seventh jig 370. By inserting the shaft 277 into the through hole 370H of the seventh jig 370, the seventh jig 370 is guided vertically downward. Eventually, the lower end of the second portion 372 of the seventh jig 370 comes into contact with the outer ring OR of the first bearing 221. Thus, the outer ring OR of the first bearing 221 is pressed downward by the seventh jig 370, while at the same time, the outer ring OR of the first bearing 221 is pre-pressurized upward by the coil spring 209 located below it. Therefore, the vertical position of the first bearing 221 is determined by the balance between the pressure from the seventh jig 370 and the pre-pressure from the coil spring 209. As this state is maintained, the adhesive 281 will eventually solidify, and the outer circumferential surface of the outer ring OR of the first bearing 221 will bond to the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207. In addition, the portion of the adhesive 281 that protruded onto at least one of the upper and lower sides of the first bearing 221 will also solidify, forming at least one of the first portion 281u and the second portion 281d of the adhesive 281.

[0066] As described above, the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207 protrudes radially inward more than the lower surface 207d. Therefore, the distance between the upper surface 207u of the inner circumferential surface 207i of the bearing housing 207 and the outer circumferential surface of the first bearing 221 is narrower than the distance between the lower surface 207d of the inner circumferential surface 207i of the bearing housing 207 and the outer circumferential surface of the second bearing 222. Consequently, even if the outer ring OR of the first bearing 221 tries to tilt relative to the shaft 277 and the bearing housing 207 due to the elastic force of the coil spring 209 during the fifth step, the outer ring OR immediately contacts the upper surface 207u, suppressing such tilting. As a result, deviations from 90° in the angles between the outer ring OR of the first bearing 221 and the shaft 277 and the bearing housing 207 are suppressed during the fifth step.

[0067] Thus, after the fifth step, the first bearing 221 is mounted at a substantially 90° angle to the shaft 277 and the bearing housing 207, respectively, and the bearing device 290 is completed.

[0068] Although preferred embodiments of the motor of the present invention have been described above, the motor of the present invention is not limited to the configuration of the above embodiments.

[0069] For example, the bearing housing, which is a retaining member, is not limited to the bearing housing 207 of the above embodiment, as long as it is configured such that the distance between it and the first bearing in the radial direction is smaller than the distance between it and the second bearing. For example, a modified bearing housing 1207, as shown in Figure 7, may be constructed. As shown in Figure 7, the inner circumferential surface 1207i of the bearing housing 1207 consists of a lower surface 1207d extending along the direction of axis X from the lower end of the inner circumferential surface 1207i to approximately half the height of the inner circumferential surface 1207i, a first stepped surface 1207e1 extending radially inward from the upper end of the lower surface 1207d, an upper surface 1207u extending along the direction of axis X from the upper end of the inner circumferential surface 1207i to near the upper end of the inner circumferential surface 1207i, a second stepped surface 1207e2 extending radially inward from the lower end of the upper surface 1207u, and a protruding surface 1207m extending along the direction of axis X from the radially inward end of the first stepped surface 1207e1 to the radially inward end of the second stepped surface 1207e2. The protruding surface 1207m includes a portion 1207f facing the first bearing 221, and the downward surface 1207d includes a portion 1207s facing the second bearing 222. By configuring the bearing housing 1207 in this way, the radial distance between the bearing housing and the first bearing can be made smaller than the distance between the bearing housing and the second bearing.

[0070] Furthermore, those skilled in the art can modify the motor of the present invention as appropriate in accordance with conventionally known knowledge. Such modifications, insofar as they still possess the configuration of the present invention, are of course included within the scope of the present invention. [Explanation of Symbols]

[0071] 1…Motor, 207,1207…Bearing housing (holding member), 207d,1207d…Lower surface, 207u…Upper surface, 277…Shaft, 281,282…Adhesive, 290…Bearing device, 1207m…Protruding surface

Claims

1. The shaft and A first bearing is positioned on one axial side of the shaft, A second bearing is positioned on the other axial side of the aforementioned shaft, A retaining member that holds the first bearing and the second bearing, Equipped with, The first bearing and the second bearing are each bonded to the retaining member with an adhesive, The inner circumferential surface of the retaining member located between the first bearing and the second bearing is on the outer circumferential surface side of the outer ring of the first bearing relative to the inner circumferential surface of the outer ring of the first bearing, and on the outer circumferential surface side of the outer ring of the second bearing relative to the inner circumferential surface of the outer ring of the second bearing, In the radial direction, the distance between the first bearing and the retaining member is smaller than the distance between the second bearing and the retaining member. In the radial direction, the width of the portion of the retaining member facing the first bearing is greater than the width of the portion of the retaining member facing the second bearing. The first and second bearings are mounted perpendicular to the shaft. Motor.

2. The adhesive material for bonding the first bearing and the retaining member is positioned on the other axial side of the first bearing. The motor according to claim 1.

3. The adhesive material for bonding the first bearing and the retaining member is arranged on one axial side of the first bearing. The motor according to claim 1 or 2.

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