JPH08331794A - Axial flow fan motor - Google Patents

Abstract

PURPOSE: To eliminate the higher pressure of an oil reservoir than an oil drip side even if a rotor is rotated, to enhance the oil retention amount of a sintered metal oil impregnated bearing and to stably improve the life of the bearing by providing one or more holes each having a specific value or less of a diameter at a resin cap. CONSTITUTION: A sealing structure in which a resin cap 7 is press injected fixedly to a housing 9 via adhesive or structural bonding material 8 is formed at one end of a bearing structure, and an oil drip 2 is press-injected fixedly to a shaft 1 at the other end. One or more holes 7b each having a diameter of 1mm or less are provided at the cap 7. Thus, even if a rotor is rotated, the pressure of an oil reservoir A does not become higher than the part B of the oil drip side, the oil is not urged to the part B by the difference of the pressure, and the oil does not flow out to the inner surface of a rotor frame 12. As a result, the oil retention amount of a sintered metal oil impregnated bearing 3 is enhanced, and the life of the bearing is stably improved.

Description

Detailed Description of the Invention

[0001]

The present invention uses a sintered oil-impregnated bearing,
The present invention relates to an axial flow fan motor used for cooling electronic equipment having a structure in which a bearing end face receives a thrust load in the axial direction.

[0002]

2. Description of the Related Art In recent years, office equipment has been reduced in noise and extended in life, and axial fan motors used for cooling electronic equipment inside the office equipment are also required to be reduced in noise and extended in life. ing. The conventional cooling axial fan motor will be described below.

5 and 6 show a bearing structure of a conventional cooling axial fan motor. In FIG. 5, reference numerals 33 and 34 denote sintered metal oil-impregnated bearings made of a copper-iron sintered alloy and held by the stator boss 43. As shown in FIG. 6, the axial end surface 34a on the motor support plate side, which is the thrust bearing surface of the sintered metal oil-impregnated bearing 34, has a height of 10 μm to
The protrusions 34b of 30 μm are formed at least at three locations evenly in the circumferential direction and the radial direction. The stator boss 43 is fixed to the housing 39 while holding the stator core 40 around which the drive winding 44 is wound. A fan 45 is press-fitted and fixed to the outer shape portion, and a permanent magnet 41 is adhered or press-fitted and fixed to the inner diameter portion of the rotor frame 42. The shaft 31 is rotatably supported by passing through the sintered metal oil-impregnated bearings 33 and 34. The other end of the shaft 31 comes into contact with the end surface 34a of the sintered metal oil-impregnated bearing 34 having a convex portion,
A thrust plate 35 made of carbon tool steel (SK material) that supports an axial force is inserted, and a stop ring 36 is press-fitted for axial positioning. Moreover, the projection 34b on the end surface of the sintered metal oil-impregnated bearing 34 and the thrust plate 35 are joined by the magnetic thrust force generated by shifting the magnetic center of the permanent magnet 41 and the magnetic center of the core 40. The oil drain 32 is press-fitted and fixed to the shaft 31. A resin cap 37 is press-fitted and fixed to a housing 39 by means of an adhesive 38 or a structural bonding material.

[0004]

However, in the above-mentioned conventional structure, when the rotor rotates, the axial direction end surface forming the thrust bearing surface is provided with the projections at least at three or more equal intervals at substantially equal intervals. The temperature of the oil-impregnated bearing rises and the oil impregnated in the sintered metal oil-impregnated bearing flows to the sliding portion between the thrust plate and the end surface of the sintered metal oil-impregnated bearing 34. A resin cap is press-fitted and fixed to the housing via an adhesive or a structural bonding material, and one end of this bearing structure is sealed. Therefore, the pressure at the oil sump A is increased and the pressure is higher than that at the oil drain side B. Becomes higher. Therefore, the oil flows to the B part, and since this part does not have a seal structure, the oil travels through the oil drainer and flows out to the inner surface of the rotor frame, and the oil retaining amount of the sintered metal oil-impregnated bearing is remarkably reduced and the bearing life is shortened. It had a problem of making it worse.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an axial fan motor having a stable and improved life.

[0006]

The present invention provides various means for solving the above problems. The axial fan motor of the first group has a seal structure in which one end of the bearing structure is press-fitted with a resin cap into the housing through an adhesive or a structural bonding material, and the other end has an oil drain on the shaft. It is fixed by press fitting. In the axial fan motor having such a structure, the resin cap has holes of φ1 mm or less at one or more places.

In the axial fan motor of the second group, one end of the bearing structure has a seal structure in which a resin cap is press-fitted and fixed to the housing through an adhesive or a structural bonding material, and the other end has an oil drainer. Is press-fitted and fixed to the shaft. An axial fan motor having such a structure has a configuration in which an oil drainer is coated with a fluorine-based inert liquid and a fluorine-based surfactant.

[0008]

In the first group, since the resin cap has a hole in this structure, even if the rotor rotates, the pressure in the oil sump A does not become higher than that in the oil drain side B, and the pressure Due to the difference, the oil will not be swept away to the B portion, and the oil will not flow out to the inner surface of the rotor frame. Therefore, the oil retaining amount of the sintered metal oil-impregnated bearing is increased, and the bearing life is stabilized and improved.

In the second group, due to this structure, even if the oil is pushed to the B portion on the oil draining side, the fluorine-based inert liquid and the fluorine-based surfactant applied to the oil drainer lower the surface tension of the oil. As a result, the oil does not easily adhere to the oil drainer, and the oil does not flow out to the inner surface of the rotor frame via the oil drainer. Therefore, the oil retaining amount of the sintered metal oil-impregnated bearing is increased, and the bearing life is stabilized and improved. Further, since the fluorine-containing inert liquid and the fluorine-containing surfactant are applied to the boss portions of the rotor frame and the insulator, the oil does not flow out from the portion B on the oil removing side.

[0010]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, reference numerals 3 and 4 denote sintered oil-impregnated bearings made of a copper-iron sintered alloy and held by the stator boss 13. As shown in FIG. 2, on the axial end surface 4a on the motor support plate side, which is the thrust bearing surface of the sintered metal oil-impregnated bearing 4, there are at least three protrusions 4b having a height of 10 μm to 30 μm in the circumferential direction and the radial direction. It is formed evenly. The stator boss 13 is fixed to the housing 9 while holding the stator core 10 around which the drive winding 14 is wound. The fan 15 is press-fitted and fixed to the outer shape portion, and the permanent magnet 11 is bonded or press-fitted and fixed to the central narrowed portion of the rotor frame 12 to the inner diameter portion. The shaft 1 passes through the sintered metal oil-impregnated bearings 3 and 4 and is rotatably supported. On the other end of the shaft 1, a sintered metal oil-impregnated bearing 4 having a convex portion is formed.
Is inserted into a thrust plate 5 made of carbon tool steel (SK material) that abuts against the end face 4a of the above and supports axial force, and a stop ring 6 is press-fitted and fixed for axial positioning. Moreover, the projection 4b on the end face of the sintered metal oil-impregnated bearing 4 and the thrust plate 5 are joined by the magnetic thrust force generated by shifting the magnetic center of the permanent magnet 11 and the magnetic center of the core. One end of this bearing structure has a sealing structure in which the resin cap 7 is press-fitted and fixed to the housing 9 via the adhesive or structural bonding material 8 and the other end has two oil drainers press-fitted and fixed to the shaft 1. Has been done. 7
The resin cap has a hole 7b with a diameter of 1 mm or less at one or more places.

As described above, according to the first embodiment, since the hole is formed in the resin cap, the pressure in the oil sump portion A does not become higher than that in the oil draining side portion B even when the rotor rotates. As a result of the difference in pressure, the oil will not be swept away to the B section, and the oil will not flow out to the inner surface of the rotor frame. Therefore, the oil retaining amount of the sintered metal oil-impregnated bearing is increased, and the bearing life is stabilized and improved.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. 3 and 4, 18 and 19 are sintered metal oil-impregnated bearings, which are made of a copper-iron sintered alloy and are held by the stator boss 28. As shown in FIG. 4, on the axial end surface 19a on the motor support plate side which is the thrust bearing surface of the sintered metal oil-impregnated bearing 19, there are at least three convex portions 19b having a height of 10 μm to 30 μm in the circumferential direction and the radial direction. It is formed evenly. The stator boss 28 is fixed to the housing 24 while holding the stator core 25 around which the drive winding 29 is wound. A fan 30 is press-fitted and fixed to the outer shape portion, and a permanent magnet 26 is adhered or press-fitted and fixed to the inner diameter portion of the rotor frame 27. The shaft 16 is rotatably supported by passing through the sintered metal oil-impregnated bearings 18 and 19. At the other end of the shaft 16, an end surface 19 of a sintered metal oil-impregnated bearing 19 having a convex portion is formed.
Carbon tool steel (SK that abuts a and supports axial force)
A thrust plate 20 made of material, and a stop ring 21 is press-fitted and fixed for positioning in the axial direction. Moreover, the projection 19b on the end face of the sintered metal oil-impregnated bearing 19 and the thrust plate 20 are joined by the magnetic thrust force generated by shifting the magnetic center of the permanent magnet 26 and the magnetic center of the core. One end of this bearing structure has a sealing structure in which the resin cap 22 is press-fitted and fixed to the housing 24 through the adhesive 23 or the structural bonding material, and the other end has 17 oil drainers press-fitted and fixed to the shaft 16. Has been done. The oil drainer has a structure in which a fluorine-based inert liquid 17b and a fluorine-based surfactant of 17b are applied. The resin cap 22 has holes 22b of φ1 mm or less at one or more places.

As described above, according to the second embodiment, since the oil is applied to the oil drainer even if the oil is washed away to the portion B on the oil drainer side, the fluorine-containing inert liquid and the fluorine-containing surfactant are not used. Since the surface tension of the oil is reduced, the oil does not easily stick to the oil drainer, and the oil does not flow out to the inner surface of the rotor frame through the oil drainer. Therefore, the oil retaining amount of the sintered metal oil-impregnated bearing is increased, and the bearing life is stabilized and improved. Further, the rotor frame 27 and the stator boss 28 have 27 bosses.
Since the fluorine-containing inert liquids b and 28b and the fluorine-containing surfactant are applied, oil does not flow out from the portion B on the oil removing side. Further, the present invention is not limited to the axial fan motor used for cooling the electronic equipment inside the office equipment, but may be a spindle motor for rotating a disk of a floppy disk device, a motor for driving a disk of various disk devices. , It can be widely applied to video tape recorder drums, capstan rotation drive motors, audio equipment reel motors, spindle motors, etc.

[0014]

As described above, according to the present invention, there is provided a sintered metal oil-impregnated bearing in which projections are provided at substantially equal intervals at least at three or more locations on the axial end surface that constitutes the thrust bearing surface when the rotor rotates. The temperature rises and the oil impregnated in the sintered metal oil-impregnated bearing flows to the sliding portion between the thrust plate and the end surface of the sintered metal oil-impregnated bearing. A resin cap is press-fitted and fixed to the housing via an adhesive or a structural bonding material, and one end of this bearing structure is sealed. Therefore, the pressure at the oil sump A is increased and the pressure is higher than that at the oil drain side B. Becomes higher. Therefore, the oil flows to the portion B, and since this portion does not have a seal structure, the oil flows out to the inner surface of the rotor frame due to the oil draining, and the oil retention amount of the sintered metal oil-impregnated bearing is significantly reduced, which deteriorates the bearing life. We have provided several bearing structures that can solve such problems. Therefore, it is possible to realize an excellent axial fan motor with stable and improved bearing life.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an axial fan motor according to an embodiment of the present invention.

FIG. 2 is a perspective view of a sintered metal oil-impregnated bearing in one embodiment of the present invention.

FIG. 3 is a partial sectional view of an axial fan motor according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a sintered metal oil-impregnated bearing according to a second embodiment of the present invention.

FIG. 5 is a partial sectional view of a conventional axial fan motor.

FIG. 6 is a perspective view of a conventional sintered metal oil-impregnated bearing.

[Explanation of symbols]

1, 16, 31 Shaft 2, 17, 32 Oil remover 3, 4, 18, 19, 33, 34 Sintered metal oil-impregnated bearing 4a, 19a, 34a Axial end surface 4b, 19b, 34b Convex portion 5, 20, 35 Thrust Plates 6,21,36 Stop rings 7,22,37 Resin caps 7b, 22b Holes 8,23,38 Adhesives or structural bonding materials 9,24,39 Housings 10,25,40 Cores 11,26,41 Permanent magnets 12, 27, 42 Rotor frame 13, 28, 43 Stator boss 14, 29, 44 Drive winding 15, 30, 45 Fan 17b, 27b, 28b Fluorine-based inert liquid and fluorine-based surfactant

Claims (4)

[Claims] Claims: 1. A sintered metal oil-impregnated bearing in which at least three projections are provided at substantially equal intervals on an axial end surface which constitutes a thrust bearing surface for supporting a shaft of a rotor; A thrust plate fixed to the shaft and abutting the end face, and the stop ring are provided, and the convex portion of the end face of the sintered metal oil-impregnated bearing and the thrust plate are pressed to make contact with each other, and In the axial flow fan motor, one end of which has a resin cap press-fitted and fixed to the housing via an adhesive or a structural bonding material, and the other end has an oil drainer press-fitted and fixed to the shaft.
An axial fan motor characterized by having holes of φ1 mm or less at more than one place. 2. A sintered metal oil-impregnated bearing in which at least three convex portions are provided at substantially equal intervals on an axial end surface which constitutes a thrust bearing surface for supporting a shaft of a rotor, and the sintered metal oil-impregnated bearing is provided. A thrust plate fixed to the shaft and abutting the end face, and the stop ring are provided, and the convex portion of the end face of the sintered metal oil-impregnated bearing and the thrust plate are pressed to make contact with each other, and In an axial flow fan motor, one end of which has a resin cap press-fitted and fixed to the housing via an adhesive or a structural bonding material, and the other end has an oil drainer press-fitted and fixed to the shaft. An axial fan motor, characterized by being coated with an oil repellent composed of a fluorine-based surfactant. 3. The axial fan motor according to claim 2, wherein an oil repellent composed of a fluorine-based inert liquid and a fluorine-based surfactant is applied to the inner surface of the rotor frame. 4. The axial fan motor according to claim 2, wherein the boss portion of the stator boss is coated with an oil repellent composed of a fluorine-based inert liquid and a fluorine-based surfactant.