WO2008056749A1 - Motor, method for manufacturing the motor, and blower fan using the motor - Google Patents

Abstract

This invention provides a bearing with a high rotation accuracy. A bearing mechanism (3) comprises a shaft (31), a cylindrical sleeve (32) formed of an oil-containing porous metal body, and a bearing housing (33) formed by pressing a metal material. The sleeve (32) is inserted into the bearing housing (33) having a cylindrical shape in its bottom. The bearing mechanism (3) further comprises a metallic annular member (35) around the shaft (31). The annular member (35) is pressed into the top end of the outer peripheral face of the bearing housing (33). As described above, the annular member (35) is fixed on the upper part of the outer peripheral face of the bearing housing (33), and an armature (221) is fixed on the outer peripheral face of the annular member (35).

Description

 Specification

 Motor, method for manufacturing the motor, and blower fan using the motor

 TECHNICAL FIELD [0001] The present invention relates to a motor including a bearing mechanism constituted by a shaft and a sleeve, and particularly relates to an improvement in a fixing structure between the bearing mechanism and an armature.

 Background art

 Conventionally, as a bearing of a motor used for a cooling fan or a disk drive device attached to various electronic devices, a sliding bearing that receives a shaft on the inner peripheral surface of the sleeve, or interposed between the shaft and the sleeve A dynamic pressure bearing is used that generates dynamic pressure in a lubricating fluid such as oil and supports the shaft against the sleeve. In particular, in a motor having a hydrodynamic bearing, high rotation, maintenance of rotation accuracy, suppression of noise, and the like are realized.

 [0003] As a technique for fixing a sleeve in a dynamic pressure bearing, a sleeve is press-fitted into a bottomed cylindrical bearing housing and fixed. However, the force S and the miniaturization of the motor are required today, it is necessary to reduce the thickness of the sleeve in the radial direction, and the inner peripheral surface of the sleeve (becomes the bearing surface) is deformed by press-fitting, and the rotational accuracy of the motor May get worse. In addition, regardless of the thickness of the sleeve in the radial direction, requirements for the rotational accuracy of the motor are becoming stricter year by year, and it is necessary to further reduce the amount of deformation of the sleeve.

 [0004] Therefore, various methods for fixing the sleeve to the bearing housing have been proposed. For example, Patent Document 1 discloses a technique of fixing the sleeve to the bearing housing by pressing the end surface of the sleeve with an elastic body and closing the inside of the bearing housing with the elastic body. Patent Document 2 discloses a technique in which a sleeve is inserted into a bearing housing, a fixing ring that presses one end surface of the sleeve is fixed to the bearing housing, and the sleeve is sandwiched between the bottom surface of the bearing housing and the fixing ring. Has been.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-352414

 Patent Document 2: Japanese Patent Application Laid-Open No. 11 252859 (see FIG. 2, FIG. 3, paragraph 0049)

 Disclosure of the invention

Problems to be solved by the invention [0006] By the way, in Patent Document 1, since it is necessary to provide a gap between the elastic body and the shaft so as not to hinder the rotation of the shaft, the lubricating fluid may flow outside the bearing depending on the use situation. May leak, and the rotational accuracy of the motor may be adversely affected. Also in Patent Document 2, there is a risk of leakage of the lubricating fluid as well.

 [0007] The present invention has been made in view of the above problems, and aims to appropriately fix the sleeve and prevent leakage of the lubricating fluid.

 Means for solving the problem

 [0008] In order to solve the above-described problem, the motor according to claim 1 of the present invention is a motor having a substantially annular rotor magnet arranged concentrically with respect to the rotation center axis. A bearing mechanism that rotatably supports the rotor portion, a substantially cylindrical bearing housing that supports the bearing mechanism, has an opening on one axial side, and has a bottom on the other axial side; A base portion to which the bearing housing is fixed, and an armature that generates torque between the rotor magnet, and the bearing mechanism includes a shaft that is fixed to the rotor portion on one side in the axial direction; A cylindrical portion fixed to the opening of the bearing housing, and an end portion on one side of the cylindrical portion. Located at the open end face of the sleeve An annular member having a protrusion protruding radially inward from the cylindrical portion so as to face the direction, and the armature is fixed to an outer surface of the annular member. To do.

 [0009] The motor according to claim 2 of the present invention is the motor according to claim 1, wherein a lubricating fluid is filled between the shaft and the sleeve in the bearing mechanism. It is characterized by.

 [0010] A motor according to a third aspect of the present invention is the motor according to the first or second aspect, wherein a radial direction between an inner peripheral surface of the projecting portion and an outer peripheral surface of the shaft in the annular member. The gap is gradually enlarged toward one side in the axial direction, and an interface between the lubricating fluid and the outside air is formed in the gap.

[0011] A motor according to claim 4 of the present invention is the motor according to any one of claims 1 to 3, wherein the protrusion of the annular member is in contact with an end surface of the sleeve. It is a feature. [0012] A motor according to a fifth aspect of the present invention is the motor according to any one of the first to fourth aspects, wherein the motor is provided on at least one of an outer peripheral surface of the shaft and an inner peripheral surface of the sleeve. A groove for generating dynamic pressure is formed.

 [0013] A motor according to a sixth aspect of the present invention is the motor according to any one of the first to fifth aspects, wherein a convex projecting radially outward is formed on an outer surface of the cylindrical portion of the annular member. A portion is formed, and the armature is in contact with the convex portion in the axial direction.

 [0014] A motor according to a seventh aspect of the present invention is the motor according to the sixth aspect, wherein the convex portion is formed in a ring shape.

 [0015] A motor according to an eighth aspect of the present invention is the motor according to any one of the first to fifth aspects, wherein the bearing housing has an outer surface on the opening side with a small diameter portion and an outer surface on the bottom side. A large-diameter portion is formed, and the cylindrical portion of the annular member is fixed to the small-diameter portion.

 The motor according to claim 9 of the present invention is the motor according to claim 8, wherein when the armature is fixed to the outer surface of the annular member, the armature is in the axial direction. It abuts on the large diameter portion.

 [0017] A motor according to a tenth aspect of the present invention is the motor according to any one of the first to fifth aspects, wherein a small-diameter portion is provided on the outer side surface on the opening side of the bearing housing, and an outer side surface on the bottom side. A large-diameter portion is formed, and when the cylindrical portion of the annular member is fixed to the small-diameter portion, the large-diameter portion and the outer diameter of the annular member are configured to have substantially the same diameter. The child is fixed across the outer surface of the large-diameter portion and the outer surface of the annular member.

 [0018] A motor according to an eleventh aspect of the present invention is the motor according to any one of the first to fifth aspects, wherein the armature is fixed when the armature is fixed to an outer surface of the annular member. Is in contact with at least a part of the base portion in the axial direction.

 [0019] A motor according to claim 12 of the present invention is the motor according to any one of claims 1 to 11, wherein the bearing housing is formed by pressing! /. To do.

[0020] A motor according to a thirteenth aspect of the present invention is the motor according to any one of the first to twelfth aspects, wherein an inner side surface at an end portion on the other side of the cylindrical portion of the annular member is The axis A gap surface S in the radial direction with respect to the outer surface of the receiving housing is formed, and a tapered surface is formed which gradually expands downward in the rotational axis direction.

[0021] A method of manufacturing a motor according to claim 14 of the present invention is a method of manufacturing a motor according to any one of claims 1 to 13, wherein the step of assembling the bearing mechanism and the bearing Attaching the mechanism to the base part, and attaching the rotor part to the rotor part fixing side of the shaft.

[0022] A blower fan according to a fifteenth aspect of the present invention is a blower fan, and the motor according to any one of the first to thirteenth aspects and the outer surface of the rotor portion are rotated to rotate the air flow. And an impeller having a plurality of blades for generating.

 The invention's effect

 [0023] In the inventions of claims 1 to 4, leakage of the lubricating fluid can be prevented. Also, in the conventional structure, the force used to fix the armature to the outer peripheral surface of the bearing housing. In this case, the sleeve fixed to the inner peripheral surface of the bearing housing is distorted when the armature is pressed into the bearing housing. There is a risk that the accuracy of the bearing will deteriorate. However, according to the present invention, since the distortion to the inner surface of the sleeve can be minimized, a bearing with high rotational accuracy can be obtained. It is also possible to restrict the movement of the sleeve in the direction of the rotation axis.

 [0024] In the inventions according to claims 5 to 10, the armature can be easily positioned in the axial direction.

 Brief Description of Drawings

 FIG. 1 is a perspective view showing a computer.

 FIG. 2 is a perspective view showing an MPU.

 FIG. 3 is a diagram showing the appearance of the fan.

 FIG. 4 is a longitudinal sectional view of the fan.

 FIG. 5 is an enlarged view showing a bearing mechanism.

 FIG. 6 is a diagram showing another example of the rotor section.

 FIG. 7 is a diagram showing how the fan is assembled.

 FIG. 8 is a view showing another example of a bearing mechanism.

 FIG. 9 is a view showing still another example of the bearing mechanism.

FIG. 10 is a view showing still another example of the bearing mechanism. Explanation of symbols

[0026] 1 fan

 2, 2a, 2b motor

 3, 3a-3e bearing mechanism

 8 computers

 11 housing

 21 Rotor

 22 Stator section

 31 shaft

 32 sleeves

 33, 33a, 33b bearing housing

 35, 35a, 35b annular members

 34 Thrust plate

 341 chip magnet

 36 gap

 39 shaft housing

 21 1a Boss

 212 rotor magnet

 213 impeller

 221 armature

 223 bearing holder

 331 contact surface

 331b cylindrical part

 BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a perspective view showing a computer 8 which is an example of an electronic apparatus. The computer 8 includes an MPU 811 for performing various calculations, a housing 81 for storing a memory for storing various information, a display 82 for displaying various information such as images, and an input unit 83 for receiving input from an operator. Have. In the computer 8, for example, an operator performs computation via the input unit 83. By performing processing input, the MPU 811 performs an operation, and the operation result is displayed on the display 82.

 FIG. 2 is a perspective view showing MPU811. On the MPU 811 is fixed a heat sink 220 made of a metal having relatively good thermal conductivity. A cooling fan 1 is fixed on the heat sink 220. As a result, the heat generated in the MPU 811 is efficiently removed by blowing cooling air from the fan 1 through the heat sink 220, and adversely affecting the arithmetic processing of the MPU 811 is prevented.

 FIG. 3 is a view showing the appearance of the fan 1. The fan 1 has a configuration in which an impeller having a plurality of blades 213 (blades) is attached to a rotor portion of an electric motor portion 2. The motor unit 2 is held by a housing 11 that surrounds the blade 213 and forms an air flow path therein.

 FIG. 4 is a longitudinal sectional view of the motor unit 2 at the position of arrows AA in FIG. The motor unit 2 includes a rotor unit 21 that is a rotating body and a stator unit 22 that is a fixed body. The rotor portion 21 is rotatably supported with respect to the stator portion 22 by a bearing mechanism 3 using fluid dynamic pressure caused by oil. The stator portion 22 is fixed to the housing 11 (see FIG. 3).

 [0031] Note that the stator portion 22 may be formed of the same metal material as the heat sink 220 of FIG. Thereby, the heat generated in the MPU 811 is removed more efficiently.

 [0032] The rotor unit 21 includes a substantially cup-shaped impeller cup 211 that covers the outside of the stator unit 22, and a substantially annular rotor magnet 212 that is magnetized so that a plurality of magnetic poles are alternately arranged in the circumferential direction. Have The impeller cup 211 is made of a synthetic resin, and a metal shaft 31 (described later) is fixed in the center! A shaft nosing 311 described later is used for a fastening portion between the impeller force head 211 and the shaft 31. The rotor magnet 212 is fixed to the inner peripheral surface of the impeller cup 211 around the shaft 31 via a yoke 212a made of a ferromagnetic material. A plurality of blades 213 are formed on the outer peripheral surface of the impeller cup 211.

However, the configuration of the impeller cup 211 is not limited to the above configuration. For example, as shown in FIG. 6, the yoke 212b is formed into a substantially lid-shaped cylindrical cup shape. Alternatively, a configuration in which the shaft 31 is press-fitted substantially in the center may be employed. In this case, the substantially cylindrical impeller hub 211b is formed by a molding method (so-called insert molding method) in which a resin is injected into the outer peripheral surface of the yoke 212b or injected into a molding die. A plurality of blades 213 are continuously formed of the same resin material as the impeller hub 21 lb on the outer peripheral surface of the impeller hub 21 lb.

 [0034] As shown in FIG. 4, the bearing mechanism 3 includes a shaft 31 and a cylindrical sleeve 32 made of an oil-containing porous metal body, and is formed by pressing a metal material. A sleeve 32 is inserted and fixed in a substantially bottomed cylindrical bearing housing 33. The bearing housing 33 is filled with oil (lubricating fluid). The shaft 31 is connected to the rotor portion 21 at the upper end side, and the opposite lower end side is inserted into the sleeve 32. The shaft 31 is rotatably supported by the sleeve 32 via oil on the lower end side. An annular metal annular member 35 centering on the shaft 31 is attached to the bearing mechanism 3 by press-fitting its cylindrical portion into the upper end of the outer peripheral surface of the bearing housing 33. At this time, in the present embodiment, both are fixed using an adhesive. Further, as shown in FIG. 5, the annular member 35 includes a protrusion 351 that protrudes radially inward above the bearing housing 33. The protruding portion 351 faces the upper end surface of the sleeve 32 in the axial direction, and the inner peripheral surface of the protruding portion 351 faces the shaft 31 in the radial direction. As a result, the annular member 35 is fixed to the bearing housing 33 so as to surround the periphery of the surface of the sleeve 32 on the rotor portion 21 side. A thrust plate 34 is provided at a position facing the end surface of the shaft 31 on the bottom surface in the bearing housing 33. The thrust plate 34 is made of a low-friction synthetic resin material and supports the shaft 31 so as to be slidable. A locking ring 38 is fixed to the lower end of the shaft 31.When the shaft 31 is used to move upward in the axial direction with respect to the sleeve 32, the locking ring 38 contacts the lower end of the sleeve 32. The shaft 31 is configured not to come out of the sleeve 32. Since the locking ring 38 is formed of an elastic body such as a springy metal or synthetic resin, the shaft 31 can be easily inserted when the locking ring 38 is elastically deformed.

A chip magnet 341 is disposed below the thrust plate 34. Therefore, the shaft 31 formed of a magnetic material is attracted in the thrust direction by the chip magnet 34. . The chip magnet 34 is attracted and fixed to the bottom of the bearing housing 33 by its magnetic force.

 The stator portion 22 has an armature 221 disposed around the annular member 35. As shown in FIG. 5, the armature 222 has a coin 2212. The end of the coil 2212 and the current supply circuit 222 are electrically connected, and the current supplied is controlled, so that the drive mechanism composed of the rotor magnet 212 and the armature 221 of the rotor section 21 has torque (rotational force). The rotor portion 21 is rotated with respect to the stator portion 22 with the shaft 31 as the rotation center axis. The magnetic center in the axial direction of the armature 221 is configured to be substantially the same position as the magnetic center in the axial direction of the rotor magnet 212. However, there may be a case where the position of the magnetic center of the armature 221 and the position of the magnetic center of the rotor magnet 212 are deviated from each other due to design circumstances. The position of the magnetic center can be changed as appropriate.

FIG. 5 is an enlarged view showing the vicinity of the bearing mechanism 3. On the bottom side in the bearing housing 33, a contact surface 331 that contacts the lower surface of the sleeve 32 is provided in an annular shape around the thrust plate 34. The bearing housing 33 is formed by pressing a metal material having a fender resistance such as stainless steel. When the sleeve 32 is fixed to the bearing housing 33 by press fitting, the inner peripheral surface of the sleeve 32 may be deformed. Therefore, in the bearing mechanism 3 of the present embodiment shown in FIG. 5, the sleeve 32 is lightly press-fitted to the bearing sleeve and the bossing 33 to such an extent that the inner peripheral surface of the sleeve 32 is not deformed. It is inserted until it touches the contact surface 331. The upper surface 325 of the sleeve 32 protrudes somewhat upward from the cylindrical portion 331b of the bearing housing 33. The annular member 35 is made of a metal material, and serves as a force with a base 350 serving as a cylindrical portion and a protrusion 351 protruding radially inward. The annular member 35 is configured such that the base portion 350 is fixed to the cylindrical portion 331b of the bearing housing 33 by press-fitting, and the protruding portion 351 of the annular member 35 and the upper surface 325 of the sleeve 32 face each other in the axial direction. Thus, in the unlikely event that the sleeve 32 is about to move in the axial direction, the movement is restricted by the protrusion 351. Further, a configuration in which the upper surface 325 of the sleeve 32 is pressed by the protrusion 351 may be employed. At this time, the lower surface of the sleeve 32 contacts the contact surface 331 in the bearing housing 33. Therefore, the sleeve 32 is an annular member 35. And the sleeve 32 is fixed to the bearing housing 33 by being sandwiched between the bearing surface 33 and the contact surface 331 in the bearing housing 33. Further, a tapered portion 351a is formed on the inner peripheral surface of the projecting portion 351 of the annular member 35 so that the dimension of the gap 36 with the outer peripheral surface of the shaft 31 is gradually increased upward. That is, the taper portion 351a is an inclined surface that moves away from the center of rotation as it goes upward in the axial direction. In the gap 36, an interface between the oil filled in the bearing housing 33 and the atmosphere is formed.

 [0038] Further, a groove for generating dynamic pressure (not shown, for example, a herringbone groove provided above and below in the axial direction) may be formed on the inner peripheral surface of the sleeve 32. The groove for generating the dynamic pressure is not limited to the inner peripheral surface of the sleeve 32, and may be formed on the outer peripheral surface of the shaft 31, for example. In this case, when the shaft 31 rotates, the gap between the shaft 31 and the sleeve 32 is bombarded by the dynamic pressure generating groove to generate fluid dynamic pressure, and the shaft 31 is not in contact with the sleeve 32. Supported against the sleeve 32 in the radial direction. The shaft 31 is supported with respect to the thrust plate 34 in the thrust direction while being slidable on the thrust plate 34.

 In the fluid dynamic pressure bearing, the setting of the dimension of the gap formed by the outer peripheral surface of the shaft 31 and the inner peripheral surface of the sleeve 32 is important. If the gap is too wide or too narrow, the dynamic pressure due to oil cannot be generated stably. Therefore, both surfaces are processed by a highly accurate machining method. The reason why the sleeve 32 is inserted into the bearing housing 33 to such an extent that the inner peripheral surface is not deformed as described above is because of the reason described above.

 As described above, the annular member 35 is fixed to the upper part of the outer peripheral surface of the bearing housing 33, and the armature 221 is fixed to the outer peripheral surface of the annular member 35. In many conventional structures, the armature 221 is directly fixed to the outer peripheral surface of the bearing housing 33. In this case, the bearing housing 33 is pressed by the armature 221 from the radially outer side to the inner side. Therefore, the bearing housing 33 is deformed inward, and in some cases, the inner peripheral surface of the sleeve 32 may be deformed.

However, in the present embodiment, the armature 22 is fixed by the bearing housing 33 via the annular member 35. For this reason, the armature 22 does not press the bearing housing 33 directly. Further, since the annular member 35 has the protruding portion 351, it is pressed in the radial direction. However, the shape is difficult to deform. Therefore, when the armature 22 is fixed to the outer peripheral surface of the annular member 35, the influence (transmission of deformation) on the inner peripheral surface of the sleeve 32 is extremely small! /.

 The bearing mechanism 3 is fixed to the housing 11 via a bearing mechanism holding part 111. The housing 11 includes a cylindrical portion 112 for fixing the bearing mechanism 3, and a bearing mechanism holding portion 111 is inserted into the inside thereof. More specifically, the housing 11 is made of a synthetic resin and formed by an injection molding method. When the housing 11 is injection-molded, the bearing mechanism holding portion 111 is placed in the molding die, and the housing 11 is formed by insert molding. The outer peripheral surface of the bearing mechanism 3 is press-fitted and fixed to the inner peripheral surface of the bearing mechanism holding portion 111. At this time, the upper surface of the cylindrical portion 112 and the lower surface of the base portion 350 of the annular member 35 are disposed so as to face each other. Further, the outer diameter of the outer peripheral surface of the cylindrical portion 112 is formed larger than the outer diameter of the outer peripheral surface of the annular member 35.

 [0043] The armature 221 is inserted to a position where the inner peripheral side of the lower surface of the stator core 2211 and the upper outer peripheral side of the cylindrical portion 112 of the housing 11 abut on each other in the axial direction. Thus, the accuracy of the axial insertion position of the armature 221 with respect to the bearing housing 33 can be increased. As described above, the magnetic center of the armature 221 is configured to be substantially the same position as the magnetic center of the rotor magnet 212. Therefore, when the fixing position of the armature 221 with respect to the bearing housing 33 is shifted, the magnetic center of the armature 221 and the magnetic center of the rotor magnet 212 are shifted. When the positions of the magnetic centers deviate from each other, electromagnetic noise accompanying vibration of the stator core 2211 is likely to occur. This is because the magnetic centers of the stator core 2211 deviate from each other in the rotational direction (axial direction), and the stator core 2211 itself vibrates and generates electromagnetic noise. one of. However, in order to generate a predetermined thrust force on the rotor portion 21, the positions of the magnetic centers may be shifted. In this case, the dimension for shifting the magnetic center is adjusted so that no electromagnetic noise is generated.

[0044] The shaft fastening portion of the impeller cup 211 has a boss portion 21la surrounding the fixed end of the shaft 31 in a cylindrical shape. A shaft housing 311 in which the shaft 31 is press-fitted and fixed is formed between the boss portion 21 la and the shaft 31. The shaft housing 311 is formed by pressing a metal material having excellent anti-corrosion properties such as stainless steel. Shaft housing Group 311 is formed by insert molding when impeller 31 is formed of synthetic resin. The shaft housing 311 has a cylindrical portion into which the shaft 31 is press-fitted in the center.

[0045] The shaft 31 has a constant gap dimension between the outer peripheral surface and the inner peripheral surface of the sleeve 32 at a portion facing the sleeve 32 in the radial direction. The dimension of the gap 36 between the outer peripheral surface of the shaft 31 and the tapered portion 351a of the annular member 35 gradually increases upward in the axial direction above the sleeve 32. This forms a taper seal in which the oil interface has a meniscus shape due to capillarity and surface tension in the gap 36, thereby preventing oil from flowing out. Further, since the taper seal is formed by the annular member 35 and the portion of the shaft 31 above the sleeve 32, the entire inner peripheral surface of the sleeve 32 can be used as a bearing surface. Compared to forming a taper seal with the outer surface of the shaft and the shaft 31, the taper seal can be provided at a position different from the position where the sleeve 32 and the shaft 31 face each other in the radial direction. Can be increased. Since the bearing housing 33 is a single member with a cylindrical shape with a bottom, no oil flows out from the bottom side.

 In the vicinity of the lower end portion of the inner peripheral surface of the base portion 350 of the annular member 35, a taper portion 350a is formed that moves away from the outer peripheral surface of the bearing housing 33 as it goes downward. The effect of the tapered portion 350a will be described below. In the present embodiment, an adhesive is applied to the fastening surface between the annular member 35 and the bearing housing 33. However, no adhesive is used when sufficient strength can be obtained simply by press-fitting the annular member 35 into the bearing housing 33. In this case, the oil filled in the bearing mechanism 3 may reach the lower end surface of the base 350 by capillary action through a minute gap formed between the annular member 35 and the bearing housing 33. . Since the taper portion 350a is formed in the lower portion of the base portion 350, an oil interface is formed in the taper portion 350a to constitute a taper seal. Therefore, the oil does not flow out of the bearing mechanism 3.

[0047] In the bearing mechanism 3, the gap between the shaft 31 and the sleeve 32, the thrust plate 34, the annular member 35, and the bearing housing 33 is filled without interruption, so that a so-called full-fill bearing mechanism is configured. The The full-fill bearing mechanism has no air inside the bearing, making it difficult for the shaft and sleeve to contact abnormally. There is an advantage that the oil does not expand and does not cause oil leakage.

Next, assembly of the fan 1 will be described. FIG. 7 shows how the fan 1 is assembled. The fan 1 includes a housing 11, a bearing mechanism 3, a stator part 22, and a rotor part 21.

 First, the bearing mechanism 3 is press-fitted into the housing 11. Next, the stator portion 22 is press-fitted into the bearing mechanism 3. At this time, the stator portion 22 is press-fitted until the stator core 2211 contacts the cylindrical portion 112, as described above. Finally, the rotor portion 21 (including the impeller) is press-fitted into the upper end of the shaft 31. In many conventional fans, the shaft is fixed to the impeller by insert molding. However, in the fan 1 of this embodiment, the shaft 31 and the impeller cannot be formed by insert molding in advance. Therefore, by inserting the shaft housing 311 into the impeller mold, the impeller is formed by insert molding as an integral member with the shaft housing 311. As a result, the shaft 31 and the impeller can be assembled after the shaft 31 is incorporated into the bearing mechanism 3. These assembling methods can also be applied to a fan having a yoke 212b shown in FIG. The fan 1 is completed by the above assembly method.

 [0050] As described above, in the bearing mechanism 3, the bearing housing 33 has the sleeve 32 that supports the shaft 31 via the lubricating fluid. Further, the annular member 35 is fitted to the outer peripheral surface of the bearing housing 33 and the upper surface 325 of the sleeve 32 is pressed and fixed, and the shaft 31 and the annular member 35 form a taper seal of the lubricating fluid. As a result, the sleeve 32 is securely fixed to the bearing housing 33 without being deformed only by the outer peripheral surface being slightly pressed by the bearing housing 33. In addition, it is possible to realize a motor with high rotational accuracy and capable of stable rotation.

Note that in order to further stabilize the high speed rotation of the motor unit 2 by the bearing mechanism shown in FIG. 5, it is preferable that the outer peripheral surface of the sleeve 32 is slightly pressed by the bearing housing 33. Even in this case, since the sleeve 32 can be stably fixed by the annular member 35, the pressing force from the bearing housing 33 can be minimized and the deformation of the sleeve 32 can be prevented. it can. By fixing the armature 35 to the outer peripheral surface of the annular member 35, the deformation of the sleeve 32 can be further prevented. By the way, if an adhesive is used for fixing the bearing housing 33 and the sleeve 32, the problem of deformation of the sleeve 32 can be avoided. However, the workability is reduced due to the adhesive application work and the waiting time until curing, etc. and the sleeve 32 is pre-impregnated with oil so that the oil oozes out on the surface and is difficult to adhere. . Therefore, the sleeve 32 that is difficult to be bonded by using the annular member 35a as described above can be easily fixed (while suppressing the pressing force of the bearing housing 33 and the like).

 FIG. 8 is a view showing a motor unit 2a of still another example, and particularly shows an enlarged vicinity of the bearing mechanism 3a. The bearing housing 33a is made of metal like the bearing housing 33 shown in FIG. However, the bearing housing 33 shown in FIG. 5 is formed by pressing a steel plate such as stainless steel, whereas the bearing housing 33a shown in FIG. 8 is formed by cutting a magnetic metal such as stainless steel. It is formed. The outer peripheral surface of the bearing housing 33a is formed with a small diameter portion 332 on the upper side and a large diameter portion 333 on the lower side. A contact surface 334 is formed at the boundary between the small diameter portion 332 and the large diameter portion 333.

 [0054] A magnetized chip magnet 341 is attracted to the bottom of the bearing housing 33a by its magnetic force. On the upper surface of the chip magnet 341, a thrust plate 34 is placed. Around the thrust plate 34, a contact surface 331 that contacts the lower surface of the sleeve 32 is provided in an annular shape. On the inner peripheral surface of the bearing housing 33a, the sleeve 32 comes into contact with the contact surface 331 and fits into the bearing housing 33a with a degree of fit that does not cause deformation of the inner peripheral surface.

Next, the fixing of the annular member 35 will be described in detail. The annular member 35 is made of a metal material, and includes a cylindrical base portion 350 and a protruding portion 351 protruding radially inward. The annular member 35 is configured such that the base portion 350 is fixed to the bearing housing 33 by press fitting, and the protruding portion 351 of the annular member 35 and the upper surface 325 of the sleeve 32 face each other in the axial direction. Thus, in the unlikely event that the sleeve 32 attempts to move in the axial direction, the movement is restricted by the protrusion 351. Further, a configuration in which the upper surface 325 of the sleeve 32 is pressed by the protrusion 351 may be employed. At this time, the lower surface of the sleeve 32 comes into contact with the contact surface 331 in the bearing housing 33a. Therefore, the sleeve 32 is fixed to the bearing housing 33a by being sandwiched between the annular member 35 and the contact surface 331 in the bearing housing 33a. Also, A tapered portion 351a is formed on the inner peripheral surface of the projecting portion 351 of the annular member 35, and a gap 36 between the outer peripheral surface of the shaft 31 and the tapered portion 351a is formed on the rotor portion 21 side (the fixed end side of the shaft 31). The oil interface is formed in the gap 36.

Similar to the bearing mechanism 3, in the present embodiment, the armature 22 is fixed to the bearing housing 33 a via the annular member 35. For this reason, the armature 22 does not directly press the bearing housing 33a. Further, since the annular member 35 has the protruding portion 351, the annular member 35 has a shape that is not easily deformed even when pressed in the radial direction. Therefore, when the armature 22 is fixed to the outer peripheral surface of the annular member 35, the influence (deformation transmission) on the inner peripheral surface of the sleeve 32 is extremely small.

 [0057] The bearing mechanism 3a is fixed to the housing 11a by insert molding. Similarly to the bearing mechanism 3, it may be fixed via a bearing mechanism holding part 111. The bearing housing 33a is molded so that only the lower portion of the large-diameter portion 333 is covered with the resin and the upper portion of the large-diameter portion 333 is exposed when it is insert-molded in the sleeve 11a. Further, the outer diameter of the large-diameter portion 333 is formed larger than the outer diameter of the annular member 35. Therefore, even in the state where the annular member 35 is attached, the contact surface 334 of the bearing housing 33a is exposed outward.

 The armature 221 is inserted to a position where the inner peripheral side of the lower surface of the stator core 2211 and the contact surface 334 are in contact with each other in the axial direction. As a result, the accuracy of the axial insertion position of the armature 221 relative to the bearing housing 33a can be increased.

 [0059] Similar to the bearing mechanism 3, a tapered portion 350a having an inner diameter gradually increasing from the outer peripheral surface of the bearing housing 33a as it goes downward is formed near the lower end portion of the inner peripheral surface of the base portion 350 of the annular member 35. Yes.

FIG. 9 is a diagram showing a motor unit 2b of still another example, and particularly shows an enlarged vicinity of the bearing mechanism 3b. The bearing housing 33b is made of metal like the bearing housing 33 shown in FIG. However, the bearing housing 33 shown in FIG. 5 is formed by pressing a steel plate such as stainless steel, while the bearing housing 33b shown in FIG. 9 is formed by cutting a metal having magnetism such as stainless steel. It is formed. The outer peripheral surface of the bearing housing 33b is formed with a small diameter portion 332b on the upper side and a large diameter portion 333b on the lower side. A contact surface 334b is formed at the boundary between the small diameter portion 332b and the large diameter portion 333b. Next, a magnetized chip magnet 341 is attracted to the bottom of the bearing housing 33b by the magnetic force. A thrust plate 34 is placed on the top surface of the chip magnet 341. Around the thrust plate 34, an abutment surface 33 lb that abuts the lower surface of the sleeve 32 is provided in an annular shape. On the inner peripheral surface of the bearing housing 33b, the sleeve 32 is inserted into the bearing housing 33b in contact with the contact surface 331b with a fit that does not cause deformation of the inner peripheral surface.

 [0062] The bearing mechanism 3b further includes a metal annular ring member 35b centered on the shaft 31, and the annular member 35b is press-fitted into the upper end portion of the outer peripheral surface of the bearing housing 33b. At this time, in this embodiment, both are fixed using an adhesive. Further, the annular member 35b includes a protrusion 351b that protrudes radially inward above the bearing housing 33b. The protruding portion 351b faces the upper end surface of the sleeve 32 in the axial direction, and the inner peripheral surface of the protruding portion 351b faces the shaft 31 in the radial direction. As a result, the annular member 35 b is fixed so as to surround the periphery of the upper surface of the sleeve 32. The annular member 35b has an annular protrusion 352b protruding outward in the radial direction on the outer peripheral surface. The annular protrusion 35 2b is formed near the lower end of the base 350b.

[0063] Next, the fixing of the annular portion 35b will be described in detail. The annular member 35b is made of a metal material and includes a cylindrical base portion 350b and a protruding portion 351b protruding inward in the radial direction. The annular member 35b is configured such that the inner peripheral surface of the base portion 350b is fixed to the outer peripheral surface of the bearing housing 33 by press-fitting, and the protruding portion 351b of the annular member 35b and the upper surface 325 of the sleeve 32 face each other in the axial direction. Thus, in the unlikely event that the sleeve 32 attempts to move in the axial direction, the movement is restricted by the protrusion 351b. Further, the upper surface 325 of the sleeve 32 may be pressed by the protrusion 351b. At this time, the lower surface of the sleeve 32 contacts the contact surface 331 in the bearing housing 33b. Therefore, the sleeve 32 is fixed between the annular member 35b and the contact surface 331 in the bearing housing 33b, thereby fixing the sleeve 32 to the bearing housing 33b. Further, a taper portion 351a is formed on the inner peripheral surface of the projection 351b of the annular member 35b, and the dimensional force of the gap 36 between the outer peripheral surface of the shaft 31 and the taper portion 351a S side of the rotor portion 21 (the shaft 31 The oil interface is formed in the gap 36. [0064] Similar to the bearing mechanism 3, in the present embodiment, the armature 22 is fixed to the bearing housing 33b via the annular member 35b. For this reason, the armature 22 does not directly press the bearing housing 33b. Further, since the annular member 35b has the protruding portion 351b, the annular member 35b has a shape that hardly deforms even when pressed in the radial direction. Therefore, when the armature 22 is fixed to the outer peripheral surface of the annular member 35b, the influence (deformation transmission) on the inner peripheral surface of the sleeve 32 is extremely small.

 [0065] The bearing mechanism 3b is fixed to the housing l ib by insert molding. Similarly to the bearing mechanism 3a, it may be fixed via a bearing mechanism holding portion 1 1 1. The bearing housing 33b is formed so that only the lower portion of the large-diameter portion 333b is covered with the resin and the upper portion of the large-diameter portion 333b is exposed when the housing is inserted into the housing rib. Therefore, even when the annular member 35b is attached, the contact surface 334b of the bearing housing 33b is exposed to the outside.

 [0066] The armature 221 is inserted to a position where the inner peripheral side of the lower surface of the stator core 221 1 and the annular protrusion 352b abut in the axial direction. Thus, the accuracy of the axial insertion position of the armature 221 with respect to the bearing housing 33b can be increased.

 [0067] Similar to the bearing mechanism 3, a tapered portion 350a is formed in the vicinity of the lower end portion of the inner peripheral surface of the base portion 350b of the annular member 35b so as to move away from the outer peripheral surface of the bearing housing 33b.

 FIG. 10 is a view showing a motor unit 2c of still another example, and particularly shows an enlarged vicinity of the bearing mechanism 3c. The bearing housing 33c has a metal force, like the bearing housing 33 shown in FIG. However, the bearing housing 33 shown in FIG. 5 is formed by pressing a steel plate such as stainless steel, while the bearing housing 33c shown in FIG. 10 is formed by cutting a magnetic metal such as stainless steel. Is done. The outer peripheral surface of the bearing housing 33c is formed with a small diameter portion 332c on the upper side and a large diameter portion 333c on the lower side. A contact surface 334c is formed at the boundary between the small diameter portion 3 32c and the large diameter portion 333c.

[0069] Next, a magnetized chip magnet 341 is attracted to the bottom of the bearing housing 33c by the magnetic force. A thrust plate 34 is placed on the top surface of the chip magnet 341. Around the thrust plate 34, a contact surface 331 that contacts the lower surface of the sleeve 32 is provided in an annular shape. The sleeve 32 is provided on the inner peripheral surface of the bearing housing 33c. The contact is brought into contact with the contact surface 331 with a fit that does not cause deformation, and is inserted into the bearing housing 33c.

 [0070] Next, the fixing of the annular portion 35c will be described in detail. The annular member 35c is formed of a metal material, and includes a cylindrical base portion 350c and a protruding portion 351c protruding inward in the radial direction. The annular member 35c is configured such that the base portion 350c is fixed to the bearing housing 33c by press-fitting, and the protruding portion 351c of the annular member 35c and the upper surface 325 of the sleeve 32 face each other in the axial direction. Thus, in the unlikely event that the sleeve 32 attempts to move in the axial direction, the movement is restricted by the protrusion 351c. Further, the upper surface 325 of the sleeve 32 may be pressed by the protrusion 351c. At this time, the lower surface of the sleeve 32 contacts the contact surface 331 in the bearing housing 33c. Therefore, the sleeve 32 is clamped between the annular member 35c and the contact surface 331 in the bearing housing 33c, so that the sleeve 32 is fixed to the bearing housing 33c. Further, a tapered portion 351a is formed on the inner peripheral surface of the projection 351c of the annular member 35c, and a gap 36 between the outer peripheral surface of the shaft 31 and the tapered portion 351a is formed on the rotor portion 21 side (the fixed end of the shaft 31). The oil interface is formed in the gap 36.

 [0071] Similar to the bearing mechanism 3, in the present embodiment, the armature 22 is fixed to the bearing housing 33c via the annular member 35c. For this reason, the armature 22 does not directly press the bearing housing 33c. Further, since the annular member 35c has the protruding portion 351c, it has a shape that is difficult to be deformed even when pressed in the radial direction. Therefore, when the armature 22 is fixed to the outer peripheral surface of the annular member 35c, the influence (deformation transmission) on the inner peripheral surface of the sleeve 32 is extremely small.

 [0072] The bearing mechanism 3c is fixed to the housing 11c by insert molding. At this time, the cylindrical portion 112c is formed of resin so as to cover a part of the outer periphery of the large diameter portion 333c of the bearing housing 33c. The upper surface of the cylindrical portion 112c is formed at a position lower than the contact surface 334c. As with the bearing mechanism 3, it may be fixed via the bearing mechanism holding part 1 1 1! When the bearing housing 33c is insert-molded into the housing 11c, only the lower portion of the large-diameter portion 333c is covered with resin, and is molded so that the upper portion of the large-diameter portion 333c is exposed. Further, the outer diameter of the large diameter portion 333c is formed to be approximately the same size as the annular member 35c.

[0073] The armature 221 has a stator core 221 1 whose inner periphery on the lower surface and the upper surface of the cylindrical portion 1 12c are in the axial direction. And is inserted to the abutting position. That is, the inner peripheral surface of the armature 221 is fixed so as to straddle the outer peripheral surface of the annular member 35c and the outer peripheral surface of the cylindrical portion 112c. As a result, the accuracy of the axial insertion position of the armature 221 relative to the bearing housing 33a can be increased.

[0074] Similar to the bearing mechanism 3, a tapered portion 350a having an inner diameter gradually increasing from the outer peripheral surface of the bearing housing 33a as it goes downward is formed near the lower end portion of the inner peripheral surface of the base portion 350 of the annular member 35. Yes.

 [0075] Although the bearing mechanism 3, 3a, 3b has been described in detail, the armature 22 can be fixed to the bearing mechanism in any shape as long as the armature 22 is fixed to the outer peripheral surface of the annular member. . It is also possible to change the design to a bearing mechanism that combines the characteristics of bearing mechanisms 3, 3a, and 3b.

 In this embodiment, the present invention may be applied to the thin centrifugal fan used in the force S described in the axial flow type fan, the notebook personal computer or the like. Since notebook PCs are often used mainly in quiet offices and homes, centrifugal fans with sleeve bearing structures (mainly fluid dynamic bearings) with high quietness are used.

Claims

The scope of the claims  [1] A motor,  A rotor portion having a substantially annular rotor magnet disposed concentrically with respect to the rotation center axis;  A bearing mechanism for rotatably supporting the rotor portion;  A substantially cylindrical bearing housing that supports the bearing mechanism, has an opening on one axial side, and has a bottom on the other axial side;  A base portion to which the bearing housing is fixed;  An armature that generates torque with the rotor magnet;  Have  The bearing mechanism is  A shaft whose one axial side is fixed to the rotor part;  A portion on the other axial side of the shaft is inserted, and a sleeve for supporting the portion;  With  A cylindrical portion fixed near the opening of the bearing housing;  An annular member is fixed, which is provided at one end of the cylindrical portion and includes a protrusion protruding radially inward from the cylindrical portion so as to face the opening end surface of the sleeve in the axial direction.  A motor, wherein the armature is fixed to an outer surface of the annular member.  2. The motor according to claim 1, wherein a lubricating fluid is filled between the shaft and the sleeve in the bearing mechanism. [3] A radial gap between the inner peripheral surface of the protrusion and the outer peripheral surface of the shaft in the annular member gradually increases toward one side in the axial direction, and the lubricating fluid and the outside air are The motor according to claim 1, wherein an interface is formed. 4. The motor according to any one of claims 1 to 3, wherein the protruding portion of the annular member is in contact with an end surface of the sleeve. [5] It moves on at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the sleeve. 5. The motor according to claim 1, wherein a groove for generating pressure is formed.  6. A convex portion projecting radially outward is formed on an outer surface of the cylindrical portion of the annular member, and the armature is in contact with the convex portion in the axial direction. A motor according to any one of 5 to 5. 7. The motor according to claim 6, wherein the convex portion is formed in an annular shape. [8] The bearing housing is characterized in that a small-diameter portion is formed on the outer surface on the opening side of the bearing housing, a large-diameter portion is formed on the outer surface on the bottom side, and the cylindrical portion of the annular member is fixed to the small-diameter portion. The motor according to any one of claims 1 to 5. 9. The motor according to claim 8, wherein when the armature is fixed to an outer surface of the annular member, the armature contacts the large diameter portion in the axial direction. [10] A small-diameter portion is formed on the outer surface on the opening side of the bearing housing, and a large-diameter portion is formed on the outer surface on the bottom side. When the cylindrical portion of the annular member is fixed to the small-diameter portion, the large-diameter portion is formed. And the outer diameter of the annular member are substantially the same, and the armature is fixed across the outer surface of the large-diameter portion and the outer surface of the annular member. Claims 1 to 5! /, A motor as described in any of the above. 11. The armature according to claim 1, wherein when the armature is fixed to an outer surface of the annular member, the armature abuts at least a part of the base portion in the axial direction. The motor according to Crab.  12. The bearing housing according to claim 1, wherein the bearing housing is formed by press working. The motor according to any one of 1 above. [13] A tapered surface on the inner side surface of the other end portion of the cylindrical portion of the annular member, in which a radial gap with the outer surface of the bearing housing gradually expands downward in the rotational axis direction. The motor according to claim 1, wherein the motor is formed.  [14] A method of manufacturing a motor according to any one of claims 1 to 13,  Assembling the bearing mechanism; Attaching the bearing mechanism to the base portion; Attaching the rotor part to the rotor part fixed side of the shaft; and a method of manufacturing a motor, comprising: A motor according to any one of claims 1 to 13,  An impeller having a plurality of blades that generate an air flow by rotating on an outer surface of the rotor portion; A blower fan comprising: