JP2000081028A - Dynamic pressure bearing device for fan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing device for a fan motor to support thrust without lowering performance of a motor through simple constitution, facilitate processing excellent in performance and durability, reduce the number of parts, also facilitate assembly, and reduce a cost. SOLUTION: A sleeve 32 is constituted that a dynamic bearing made of resin formed integrally with a radial thrust is provided with a radial dynamic pressure bearing part having a groove 32a for generating a dynamic pressure formed in an inside diameter surface and a thrust bearing part connected thereto and formed at a bottom. An axial suction force exerted on a gap between a stator 40 and a rotor 34 is increased to a value higher thrust (c) generated through rotation of a blade 35 and the rotor 34 is axially sucked and a thrust load based on the axial suction force and the thrust (c) of the blade is supported by the surface of the free end of a rotary shaft 31 and the thrust bearing of a dynamic pressure bearing made of resin formed integrally with a radial thrust. A radial load is supported by the outside diameter surface of the rotary shaft 31 and the radial dynamic pressure bearing part of a dynamic pressure bearing made of resin formed integrally with the radial thrust.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dynamic bearing device for a fan motor.

[0002]

2. Description of the Related Art Conventionally, as a fan motor used for office machines and the like, there is one shown in FIG.
No. 101154 (Japanese Utility Model Application No. 2-8215). The fan motor 10 includes a rotating shaft 11, a sleeve 12 into which the rotating shaft 11 is rotatably fitted, and a receiving member 13 that supports the rotating shaft 11 in the axial direction. Rotating shaft 11
Is connected to the rotor 14 at one end. Rotor 14
Consists of a support member 17 provided with a blade 15 and a magnet 16. The outer peripheral surface of the rotating shaft 11 is provided with a dynamic pressure generating portion (dynamic pressure groove) 11a. The sleeve 12 is fixed to a case 19 via a support member 18. Further, the stator 20 is also fixed to the case 19 via the support member 18. The magnet 16 of the rotor 14 and the stator 20 are arranged to face each other in the radial direction. The dynamic pressure bearing unit 2 includes the rotary shaft 11 provided with the dynamic pressure generation unit 11a and the sleeve 12.
1 is configured. The receiving member 13 is made of a resin material, and is fixed to the case 19. The cylindrical space S formed between the rotating shaft 11 and the sleeve 12 is filled with grease.

[0003] The rotor 14 having the blades 15 is radially supported via the dynamic pressure bearing portion 21, and the rotor 14 having the blades 15 is rotatably supported around the stator 20. The rotor 14 is rotated by the rotating magnetic field generated by the stator 20 to rotate the blades 15 to generate an airflow in a direction indicated by an arrow X in the drawing. The thrust load (arrow Y in the figure) acting on the rotating shaft 11 as a reaction force of the thrust of the blade 15 is supported by the axial component of the attractive force acting between the iron core of the stator 20 and the magnet 16 of the rotor 14. The positions of the stator 20 and the magnet 16 of the rotor 14 are shifted in the axial direction so that the attraction force becomes larger than the thrust load generated by the thrust of the blade 15 by a certain ratio, and the remaining thrust load is The end face of 11 is made to contact and support a receiving member 13 made of resin provided on a case 19.

[0004]

However, in the conventional fan motor bearing, the number of parts of the bearing is two, that is, the sleeve and the receiving member. Therefore, the number of assembling steps is large and the structure is complicated. Furthermore, high machining accuracy is required for the perpendicularity of the shaft end face that supports the thrust load. Furthermore, since a high assembling accuracy is required for the perpendicularity and the like when assembling the radial bearing inner diameter portion and the thrust receiving surface of the thrust receiving member, there is a problem that cost reduction cannot be achieved.

[0005] Further, by displacing the stator in the axial direction with respect to the rotor, the axial component of the attraction force acting on the iron core of the stator and the magnet of the rotor is made larger than the thrust of the blade, thereby reducing the thrust of the blade. However, since the rotor is attracted in the axial direction by the magnetic force in the opposite direction to the axial direction, there is also a problem that the dimension in the axial direction is increased, which hinders compactness. Further, since a large suction force is required as described above, the axial positions of the stator and the rotor must be largely shifted, and there is a problem that noise is easily generated. If the thrust of the blade is increased, the above problem is further increased, and the blade may not be used as a fan motor.

Also, at the time of stop, the rotary shaft is tilted by the bearing clearance, and both the end face of the shaft receiving the thrust load and the surface of the thrust receiving member are flat. There is also a problem that the surface of the thrust receiving member is easily damaged due to contact with the surface of the receiving member.

Further, since grease is used as a lubricant, it is difficult to discharge air inside the bearing when the rotary shaft is inserted into the sleeve. There is also a problem that the performance of the motor decreases and a problem that the torque increases.

Accordingly, an object of the present invention is to provide a simple structure capable of supporting the thrust generated by the rotation of the blades without deteriorating the performance of the motor, having excellent performance and durability, easy processing, small number of parts, and assembling. Another object of the present invention is to provide a dynamic bearing device for a fan motor which is easy and inexpensive.

[0009]

SUMMARY OF THE INVENTION The present invention provides a hydrodynamic bearing device for a fan motor, which comprises a one-piece, completely integrated resin hydrodynamic bearing for supporting a radial load and a thrust load on a rotating shaft of the fan motor. It is to be provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dynamic pressure bearing device for a fan motor according to the present invention is provided with a rotating shaft having a rotor having blades fixed to one end and having a free end at the other end, and a stator facing the rotor. And a case in which a rotating shaft is fitted into the substantially central portion with a gap therebetween and a substantially cylindrical sleeve that forms a dynamic pressure bearing portion together with the rotating shaft is provided, and the fan motor rotatably supports a rotor having blades. In a dynamic pressure bearing device for use, a sleeve has a radial dynamic pressure bearing portion provided with a groove for generating dynamic pressure on an inner diameter surface and a thrust bearing portion provided on a bottom surface connected to the sleeve, and is made of a resin made of a radial / thrust unit. A pressure bearing is formed, and the stator is disposed to face the rotor in the axial direction, and the suction force acting between the stator and the rotor in the axial direction is made larger than the thrust generated by the rotation of the blades. And the thrust load based on the axial suction force and the thrust of the blade is supported by the free end surface of the rotating shaft and the thrust bearing portion of the resin dynamic pressure bearing integrated with the radial and thrust. The load is supported by the outer diameter surface of the rotating shaft and the radial dynamic pressure bearing portion of the resin dynamic pressure bearing integrated with the radial and thrust in a non-contact manner.

In the above-described dynamic bearing device for a fan motor, the thrust load obtained by subtracting the thrust of the blade from the axial suction force is applied to the free end surface of the rotating shaft and the radial / thrust integrated resin dynamic bearing. May be supported.

Further, the groove for generating dynamic pressure of the radial dynamic pressure bearing portion generates a radial force and a thrust force acting in the same direction in the axial direction with respect to the thrust generated by the rotation of the blades of the fan motor. It may be formed of a groove pattern, and the axial suction force acting between the stator and the rotor may be made larger than the resultant force obtained by adding the thrust force generated by the rotation of the blade to the thrust force generated by the groove for generating dynamic pressure.

The groove for generating the dynamic pressure of the radial dynamic pressure bearing portion is a groove for generating a radial force and a thrust force acting in the axial direction opposite to the thrust generated by the rotation of the blades of the fan motor. The resultant may be a pattern, and the resultant force obtained by adding the thrust force generated by the groove for generating dynamic pressure to the axial suction force acting between the stator and the rotor may be larger than the thrust generated by the rotation of the blade.

Further, one of the free end surface of the rotating shaft and the surface of the thrust bearing portion of the resin dynamic pressure bearing integrated with the radial and thrust may be formed into a spherical surface, and oil may be used as a lubricant.

In the dynamic pressure bearing device for a fan motor according to the present invention, the sleeve includes a radial dynamic pressure bearing portion provided with a groove for generating dynamic pressure on an inner diameter surface and a thrust bearing portion provided on a bottom surface connected thereto. By forming the radial and thrust integrated resin dynamic pressure bearing having the above, the radial and thrust integrated resin dynamic pressure bearing can be formed by injection molding, so that processing is easy and the number of parts is reduced. . Further, since all the bearings are made of resin, the friction is low and the wear resistance is excellent.

Further, since the stator of the cooling fan motor is disposed to face the rotor in the axial direction, the rotor is positioned to the stator as in the case where the conventional stator is disposed to face the rotor in the radial direction. Thus, a force for attracting the rotor in the axial direction can be generated between the stator and the rotor without performing a method such as shifting the position in the axial direction. Therefore, the axial dimension of the fan motor bearing device can be reduced, and there is no problem such as generation of noise.

Further, even when the axial suction force acting between the stator and the rotor is much larger than the thrust generated by the blade, the groove for generating the dynamic pressure on the inner diameter surface of the radial dynamic pressure bearing portion is formed by the radial force. And a groove pattern that generates a thrust force acting in the same direction in the axial direction with respect to the thrust generated by the rotation of the blades of the fan motor, so that the thrust load applied to the thrust bearing portion can be reduced.

Further, even when the thrust generated by the rotation of the blade is larger than the axial suction force acting between the stator and the rotor, the groove for generating the dynamic pressure on the inner diameter surface of the radial dynamic pressure bearing portion is formed by the radial force. And a groove pattern that generates a thrust force acting in the axial direction opposite to the thrust generated by the rotation of the fan motor blades, so that the thrust force generated by the dynamic pressure generation groove and the motor It is possible to make the resultant force with the axial suction force larger than the thrust generated by the rotation of the blade.

Further, the radial and thrust integrated dynamic pressure bearing is formed of a resin material, and one of the surface of the free end of the rotating shaft and the surface of the thrust bearing portion is made to have a spherical surface and receives a thrust load by point contact. By doing so, the friction is reduced and the surface of the thrust bearing is not damaged by the edge of the rotating shaft. Furthermore, since the radial dynamic pressure bearing portion is also made of a resin material, the frictional resistance at the time of starting (the outer surface of the rotating shaft and the inner surface of the sleeve come into contact at the time of starting and stopping) can be reduced, and the wear resistance is excellent. .

Further, by using oil as a lubricant,
When the rotating shaft is inserted into the radial and thrust-integrated resin dynamic pressure bearing, the air inside the resin dynamic pressure bearing can be easily discharged, and the air is hardly left inside the resin dynamic pressure bearing. The performance as a bearing does not decrease. Furthermore, when oil is used as the lubricant, the torque is smaller than when grease is used as the lubricant.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a hydrodynamic bearing device 30 for a fan motor according to a first embodiment of the present invention. An axially extending cylindrical portion 39 a is provided at the center of the case 39. A stator 40 is fixed to the outer periphery of the cylindrical portion 39a via a support member 38. Stator 40 has a coil. A bottomed resin sleeve 32 is fixed to the inner diameter of the cylindrical portion 39a. A rotating shaft 31 having one end fixed to a rotor 34 having a blade 35 is rotatably inserted in the inner diameter portion of the resin sleeve 32 with a certain gap in the radial direction and freely inserted and removed, and is inserted into the resin sleeve 32. A radial dynamic pressure bearing portion provided with a groove 32a for generating dynamic pressure on the inner diameter surface thereof and a thrust bearing portion provided with a spherical surface 32b provided on the bottom surface of the resin sleeve 32 are made of a resin made of radial and thrust. It constitutes a dynamic pressure bearing. The bearing gap S ′ formed between the rotating shaft 31 and the radial and thrust-integrated resin dynamic pressure bearing is filled with oil as a lubricant.

The stator 40 supports the support member 3 of the rotor 34.
7 is provided so as to face the magnet 36 fixed to 7 in the axial direction. The rotor 34 is rotatably supported via a resin dynamic pressure bearing. The rotor 34 includes a stator 40
Is rotated in the direction indicated by the arrow a in the figure due to the rotating magnetic field generated by the rotor, and air is blown in the direction indicated by the arrow b by the blades 35 provided on the outer periphery thereof. At the time of this rotation, the resin sleeve 32
A pressure is generated in the oil by the dynamic pressure generating groove 32a on the inner diameter surface of the sleeve 32, and the rotating shaft 31 is supported in the radial direction, and the rotating shaft 31 rotates without contact with the inner diameter surface of the resin sleeve 32. The remaining thrust load (the thrust force (arrow c in the drawing) acting on the rotating shaft 31 as a reaction force of the blowing action of the blade 35 at the time of blowing) is subtracted from the axial suction force acting between the stator 40 and the rotor 34. The suction force of the motor) is supported by bringing the spherical surface 32b of the thrust bearing into contact with the surface of the free end of the rotating shaft 31.

As described above, the grooves 32 for generating dynamic pressure are formed on the inner diameter surface.
a and a thrust bearing integrated resin radial pressure bearing provided with a thrust bearing portion on the bottom surface connected thereto.
Since the thrust-integrated dynamic bearing made of resin can be formed by injection molding, the groove 32a for generating dynamic pressure can be provided at the time of injection molding, and processing is easy and the number of parts is reduced. Further, the assembling is easy, so that the cost can be reduced.

The motor stator 40 is connected to the rotor 34.
Since it is arranged to face the magnet 36 in the axial direction, it is not necessary to adopt a structure in which the attracting force of the motor that overcomes the thrust generated by the rotation of the blade is forcibly generated by shifting the stator and the rotor in the axial direction. Therefore, no noise or the like is generated, the structure is simple, and the axial dimension can be reduced, so that the device can be made compact (thin).

The radial and thrust integrated dynamic pressure bearing is formed of a resin material, and one of the free end surface of the rotating shaft 31 and the surface of the thrust bearing portion is formed into a spherical surface 32b, and the thrust load is formed by point contact. As a result, the friction is reduced, and the edge of the rotating shaft 31 does not damage the surface of the thrust bearing. Furthermore, since the radial dynamic pressure bearing portion is also made of a resin material, the frictional resistance at the time of startup (the outer surface of the rotary shaft 31 and the inner surface of the sleeve 32 at the time of startup and stoppage) can be reduced, and the radial and thrust integral can be reduced. Low friction and excellent wear resistance as a whole.

Also, by using oil as a lubricant,
When the rotating shaft 31 is inserted into the resin dynamic pressure bearing integrated with the radial and thrust, the air inside the resin dynamic pressure bearing is easily discharged, and the air is hardly left inside the resin dynamic pressure bearing. The performance as a bearing does not decrease. Further, when oil is used as the lubricant, the torque is smaller than when grease is used as the lubricant.

FIG. 2 is a sectional view of a dynamic bearing device 50 for a fan motor according to a second embodiment of the present invention. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The difference from the first embodiment is that a cylindrical portion extending in the axial direction is not provided at the center of the case 59, and the sleeve 52 constituting the resin dynamic pressure bearing is directly fixed to the case 59. And the stator 40 is directly fixed to the outer diameter surface of the sleeve 52 via the support member 38. Since the structure of the case 59 is simplified, there is an advantage that the processing cost is reduced. Other functions and effects are the same as those of the first embodiment.

3 (1), (2), (3) and (4) are cross-sectional views of a resin sleeve (a resin dynamic pressure bearing integrated with radial and thrust) according to a third embodiment of the present invention. The other parts are the same as in the first and second embodiments, and are omitted. In FIG. 3A, the center of a thrust bearing 62c provided at the bottom of the sleeve 62 is formed as a convex spherical surface 62b, and two grooves for generating dynamic pressure are provided on the inner diameter surface of the sleeve 62. The width of 62a is A> B, C> D, and the width of the upper side of each of the two grooves 62a is wider. Therefore, A + C> B + D, and a thrust force (axial force) (d) is generated in the axial direction with respect to the radial force and the thrust (c) of the blade. The groove pattern (groove width ratio) is set such that the resultant force obtained by adding the thrust (c) generated by the groove pattern to the thrust (c) of the blade is smaller than the suction force of the motor.

When the rotor rotates in the direction indicated by the arrow a in the figure, the dynamic pressure for supporting the shaft in the radial direction by the dynamic pressure generating groove 62a and the thrust force (c) in the same direction with respect to the thrust (c) of the blade. A force (d) for lifting the rotating shaft 31 from the thrust bearing portion 62c is generated. At this time, the resultant force obtained by adding the thrust force (d) generated by the groove 62a for generating the dynamic pressure and the thrust (c) of the blade is smaller than the suction force of the motor, and the suction force (thrust load) of the remaining motor is The free end surface of the rotating shaft 31 and the spherical portion 6 of the thrust bearing portion 62c
2b.

The suction force of the motor is too large than the thrust (c) of the blade.
Even when the thrust load applied to the motor 2c is large, the suction force of the motor is balanced by the thrust force (c) of the blade and the thrust force (d) generated by the groove 62a for generating the dynamic pressure. Since the thrust load can be received by the point contact between the free end surface of the shaft 31 and the spherical portion 62b of the thrust bearing portion 62c, the rotational torque can be reduced, and the free end surface of the rotating shaft 31 and the spherical surface of the thrust bearing portion 62c can be reduced. Part 6
Wear with 2b can also be reduced. Other functions and effects are the same as those of the first and second embodiments.

FIGS. 3 (2) and 3 (3) show examples of groove patterns of other grooves for generating dynamic pressure. The width of the dynamic pressure generating groove 72a in FIG. 3 (2) is A> B, C = D, and the width of the dynamic pressure generating groove 82a in FIG. 3 (3) is A> B, C <D. However, both have A + C> B + D, and therefore have the same operation and effect as the embodiment of FIG. 3A. Other operations and effects are the same as those of the first and second embodiments.

FIG. 3D shows an example in which a groove 92a for generating dynamic pressure is provided at one position in the axial direction. Groove 92a for generating dynamic pressure
Is greater than A, and as in the other groove patterns, when the rotor rotates in the direction indicated by the arrow a in the figure, the dynamic pressure for supporting the rotating shaft 31 in the radial direction by the dynamic pressure generating grooves 92a. Then, a thrust force in the same direction (force (d) for floating the rotating shaft 31 from the thrust bearing portion 92c) is generated with respect to the thrust of the blade (force (c) generated in the axial direction). This example also has the same operation and effect as the examples of the other groove patterns. Other operations and effects are the same as those of the first and second embodiments.

FIGS. 4 (1), (2), (3), and (4) are cross-sectional views of a resin sleeve (a resin dynamic pressure bearing integrated with radial and thrust) according to a fourth embodiment of the present invention. The other parts are the same as in the first and second embodiments, and are omitted. In FIG. 4A, the center of a thrust bearing 102c provided at the bottom of the sleeve 102 is formed as a convex spherical surface 102b, and the center of the thrust bearing 102c is provided at the inner surface of the sleeve 102.
The widths of the dynamic pressure generating grooves 102a are A <B, C <D, and the widths of the two grooves 102a on the lower side are wide. Therefore, A + C <B + D, and a thrust force (axial force) (e) in the axial direction opposite to the radial force and the thrust (c) of the blade is generated. The groove pattern (groove width ratio) is set so that the resultant force obtained by adding the suction force of the motor to the thrust force (e) generated in the groove pattern is larger than the thrust (c) of the blade.

When the rotor rotates in the direction indicated by the arrow a in the figure, the dynamic pressure for supporting the shaft in the radial direction by the dynamic pressure generating groove 102a and the thrust force in the direction opposite to the thrust (c) of the blade ( A force (e) for pushing the rotating shaft 31 against the thrust bearing portion 102c is generated. At this time, the thrust force (e) generated by the dynamic pressure generating groove 102a
And the suction force of the motor are greater than the thrust (c) of the blade, and the thrust load is received by point contact between the free end surface of the rotating shaft 31 and the spherical portion 102b of the thrust bearing portion 102c.

Even when the thrust (c) of the blade is larger than the suction force of the motor and the rotor (rotary shaft 31) is lifted by only the suction force of the motor, the thrust (c) of the blade is reduced by the suction force of the motor. A thrust load is received by a point contact between the free end surface of the rotating shaft 31 and the spherical portion 102b of the thrust bearing portion 102c by balancing the force and the thrust force (e) generated by the groove 102a for generating dynamic pressure. Therefore, the rotational torque can be reduced, and the surface of the free end of the rotating shaft 31 and the spherical portion 102b of the thrust bearing portion 102c can be reduced.
Wear can also be reduced. Other functions and effects are the same as those of the first and second embodiments.

FIGS. 4 (2) and 4 (3) show examples of groove patterns of other grooves for generating dynamic pressure. The width of the dynamic pressure generating groove 112a in FIG. 4 (2) is A <B, C = D, and the width of the dynamic pressure generating groove 122a in FIG. 4 (3) is A <B, C> D. There is
Since both of them satisfy A + C <B + D, they have the same operations and effects as the embodiment of FIG. Other operations and effects are the same as those of the first and second embodiments.

FIG. 4 (4) shows an example in which a groove 132a for generating dynamic pressure is provided at one location in the axial direction. Groove 132 for generating dynamic pressure
The width of a is A <B, and when the rotor rotates in the direction indicated by the arrow a in the drawing, as in the other groove pattern examples, the dynamic pressure generating groove 132a supports the rotating shaft 31 in the radial direction. Pressure and thrust of blade (force generated in axial direction) (c)
, A thrust force (force pressing the rotating shaft 31 toward the thrust bearing portion 132c) (e) is generated. This example also has the same operation and effect as the examples of the other groove patterns. Other operations and effects are the same as those of the first and second embodiments.

As a resin material for forming the sleeve in each of the above embodiments, PPS (polyphenylene sulfide resin) containing carbon fiber is preferable because of its strength and excellent abrasion resistance, but the resin material is not limited to this. Not something. Further, the outer diameter shape of the sleeve is not limited to the present embodiment, and may be irregular or provided with a flange or the like. The fixing of the sleeve and the case may be performed by bonding, press-fitting, fixing the flange portion to a screw, or the like, or may be a combination of the above fixing methods, and is not limited to these fixing methods. Further, the groove pattern of the groove for generating dynamic pressure is not limited to the example shown in the above embodiment, but may be any groove pattern and groove width ratio functioning as a dynamic pressure bearing.

[0039]

The present invention is embodied in the form described above and has the following effects.

The dynamic pressure bearing device for a fan motor of the present invention comprises:
The sleeve forms a radial-thrust integrated resin dynamic pressure bearing having a radial dynamic pressure bearing portion provided with a groove for generating dynamic pressure on the inner diameter surface and a thrust bearing portion provided on the bottom surface connected thereto. With this arrangement, the resin-made dynamic pressure bearing integrated with the radial and thrust can be formed by injection molding, so that there is an effect that processing is easy and the number of parts is reduced. Furthermore, since all the bearings are made of resin, there is an effect that the friction is low and the wear resistance is excellent.

Further, since the stator of the cooling fan motor is arranged to face the rotor in the axial direction, the rotor is fixed to the stator as in the case where the conventional stator is arranged to face the rotor in the radial direction. Thus, a force for attracting the rotor in the axial direction can be generated between the stator and the rotor without performing a method such as shifting the position in the axial direction. Accordingly, the axial dimension of the fan motor bearing device can be reduced, and further, there is an effect that there is no problem such as generation of noise.

The groove pattern of the groove for generating dynamic pressure of the radial dynamic pressure bearing portion generates a radial force and a thrust force acting in the same direction or in the opposite direction in the axial direction with respect to the thrust of the blade. Due to the groove pattern, even if the axial suction force acting between the stator and the rotor is much larger than the thrust generated by the blade, or if the thrust generated by the rotation of the blade is larger than the motor's suction force In addition, since the thrust force can be balanced and the thrust load applied to the thrust bearing can be reduced, there is an effect that the wear of the thrust bearing can be reduced.

Also, the radial and thrust-integrated hydrodynamic bearing is formed of a resin material, and one of the surface of the free end of the rotating shaft and the surface of the thrust bearing portion is made spherical to receive a thrust load by point contact. By doing so, there is an effect that the friction is low and the edge of the rotating shaft does not damage the surface of the thrust bearing portion. Furthermore, since the radial dynamic pressure bearing portion is also made of a resin material, the frictional resistance at the time of starting (the rotating shaft and the inner surface of the sleeve contact at the time of starting and stopping) can be reduced, and the wear resistance is excellent. To play.

Also, by using oil as a lubricant,
When the rotating shaft is inserted into the radial and thrust-integrated resin dynamic pressure bearing, the air inside the resin dynamic pressure bearing can be easily discharged, and the air is hardly left inside the resin dynamic pressure bearing. The effect that the performance as a bearing does not fall is produced. Furthermore, when oil is used as a lubricant, there is an effect that torque is smaller than when grease is used as a lubricant.

[Brief description of the drawings]

FIG. 1 is a sectional view of a dynamic pressure bearing device for a fan motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a dynamic pressure bearing device for a fan motor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a resin sleeve (dynamic pressure bearing portion) according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a resin sleeve (dynamic pressure bearing portion) according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a conventional fan motor bearing device.

[Explanation of symbols]

 Numeral 30: dynamic pressure bearing device for fan motor 31: rotary shaft 32: sleeve 32a: groove for generating dynamic pressure 32b: spherical surface 34: rotor 35: blade 36: magnet 39: Case 40: Stator a: Rotating direction of rotating shaft b: Blowing direction c: Thrust of blade d, e: Thrust force generated by grooves for generating dynamic pressure

Claims (5)

[Claims] A rotor having blades fixed to one end thereof and having a free end at the other end; and a stator opposed to the rotor disposed at a substantially central portion with a gap therebetween. A case provided with a substantially cylindrical sleeve that is fitted and constitutes a dynamic pressure bearing portion together with the rotating shaft, wherein the dynamic pressure bearing device for a fan motor rotatably supports the rotor having the blades. Forms a radial-thrust integrated resin dynamic pressure bearing having a radial dynamic pressure bearing portion provided with a groove for generating dynamic pressure on the inner diameter surface and a thrust bearing portion provided on the bottom surface connected thereto. The stator is disposed to face the rotor in the axial direction, and the axial suction force acting between the stator and the rotor is made larger than the thrust generated by the rotation of the blade. A thrust bearing portion of a resin dynamic pressure bearing integrated with the surface of the free end of the rotating shaft and the radial and thrust, wherein the rotor is suctioned in the axial direction and a thrust load based on the axial suction force and the thrust of the blade is applied. Wherein the radial load is supported in a non-contact manner by an outer diameter surface of the rotary shaft and a radial dynamic pressure bearing portion of a resin dynamic pressure bearing integrated with the radial and thrust. apparatus. 2. A thrust load obtained by subtracting a thrust of the blade from the axial suction force is supported by a free end surface of the rotary shaft and a thrust bearing portion of the radial and thrust integrated resin dynamic pressure bearing. The dynamic pressure bearing device for a fan motor according to claim 1, wherein: 3. The dynamic pressure generating groove of the radial dynamic pressure bearing portion generates a radial force and a thrust force acting in the same axial direction with respect to a thrust generated by rotation of the blade. A groove pattern, wherein the axial suction force acting between the stator and the rotor is larger than a resultant force obtained by adding the thrust force generated by the groove for generating dynamic pressure to the thrust generated by rotation of the blade. 2. The dynamic pressure bearing device for a fan motor according to claim 1, wherein the size is large. 4. The groove for generating dynamic pressure of the radial dynamic pressure bearing portion generates a radial force and a thrust force acting in a direction opposite to an axial direction with respect to a thrust generated by rotation of the blade. It is composed of a groove pattern, and the resultant force obtained by adding the thrust force generated by the groove for generating dynamic pressure to the axial suction force acting between the stator and the rotor is larger than the thrust generated by rotation of the blade. The dynamic pressure bearing device for a fan motor according to claim 1, wherein: 5. One of a surface of a free end of the rotary shaft and a surface of the thrust bearing portion of the resin dynamic pressure bearing integrated with the radial and thrust has a spherical surface, and oil is used as a lubricant. The dynamic pressure bearing device for a fan motor according to claim 1, wherein: