JP2000060063A - Fan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple structure for supporting a thrust load acting as a reaction force of a blade with excellent performance and durability, easy to process and assemble, with a small number of parts, and a blade. SOLUTION: From a radial dynamic thrust integrated resin dynamic pressure bearing provided with a radial dynamic pressure bearing portion having a groove for generating dynamic pressure on the inner surface of a cylindrical portion and a thrust bearing portion on the cylindrical portion bottom surface connected thereto. A stator is provided directly on the outer diameter surface of the outer diameter portion of the sleeve, and the groove for generating dynamic pressure on the inner surface of the cylindrical portion generates a force acting in the direction opposite to the thrust of the blade in the axial direction. A groove pattern, wherein one of the free end of the rotating shaft and the thrust bearing surface is spherical,
Provided is a fan motor including a dynamic pressure bearing for a fan motor using oil as a lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan motor, and more particularly to a fan motor using a radial and thrust integrated resin bearing, and more particularly to a fan motor excellent in performance and durability and easy to process and assemble. About.

[0002]

2. Description of the Related Art A conventional fan motor used for office machines and the like is disclosed in Japanese Utility Model Application No. 2-8215. FIG. 7 is a sectional view of a conventional fan motor dynamic pressure bearing device. The rotor 101 is fixed to the inner peripheral portion of the support member 103, and the blade 100 is fixed to the outer peripheral portion. The rotor 101 is composed of a magnet 102. The support member 103 is fixed to one end of a rotating shaft 107 having a dynamic pressure generating portion (dynamic pressure generating groove 106). A cylindrical sleeve 105 is provided at the center of the case 109 so as to protrude into a cylindrical member 112, and a stator 104 is fixed to the outer periphery of the cylindrical member 112 so as to face the rotor 101. A receiving member 110 made of resin for supporting the rotating shaft 107 is attached to the case 109 below the sleeve 105. The rotating shaft 107 is rotatably fitted to the sleeve 105 to form a dynamic pressure bearing 108, and a cylindrical space formed between the sleeve 105 and the rotating shaft 107 is filled with grease 111. The blade 100 and the rotor 101 are supported in the radial direction via the dynamic pressure bearing 108, and the blade 100 and the rotor 101 are fixed to the stator 104.
It is rotatably supported around. That is, the stator 1
The rotor 101 is rotated by the rotating magnetic field generated by the rotor 04 to rotate the blade 100 (in the direction indicated by the arrow Z in the figure),
An air flow is generated and blown in the direction indicated by arrow X in the figure. A thrust load (arrow Y in the drawing) acting on the rotating shaft 107 as a reaction force of the thrust of the blade 100 is supported by an axial component of an attractive force acting between the iron core of the stator 104 and the magnet 102 of the rotor 101. The positions of the stator 104 and the rotor 101 are shifted in the axial direction so that the suction force becomes larger than the thrust load generated by the thrust of the blade 100 by a certain ratio. Then, the remaining thrust load of the axial component obtained by subtracting the thrust of the blade 100 from the suction force acting between the stator 104 and the rotor 101 is applied to the resin receiving member 110 provided with the end face of the rotating shaft 107 in the case 109. It was in contact and supported.

[0003] However, the conventional fan motor bearing has two parts, the radial dynamic pressure bearing portion and the thrust receiving member (resin receiving member 110). . Furthermore, high machining accuracy is required for the perpendicularity of the shaft end surface that supports the thrust load, and cost reduction cannot be achieved. When the fan motor is stopped, the rotating shaft 37 is tilted down by the bearing gap, and the shaft end face receiving the thrust load and the thrust receiving member surface are flat. Therefore, when the fan motor starts and stops, the edge of the shaft end contacts the thrust receiving member surface, and the thrust receiving member surface is easily damaged. Further, by shifting the position of the stator 104 in the axial direction with respect to the rotor 101,
The axial component of the attractive force acting on the iron core of the stator 104 and the magnet 102 of the rotor 101 is made larger than the thrust of the blade 100, and the rotor 101 is attracted in the axial direction by the magnetic force in the direction opposite to the thrust of the blade 100 in the axial direction. Therefore, the dimension in the axial direction increases. Further, a member (cylindrical member 112) for attaching the stator 104 is required, which hinders the downsizing (thinness) of the entire fan motor. Further, since the thrust of the blade 100 increases with the number of rotations, it is necessary to generate a magnetic force in the opposite direction which is larger than the thrust generated in the steady rotation by the magnet 102. Therefore, when the blade 100 is rotating at a low speed with a small thrust, a large thrust load acts on the thrust member and the blade 100 is easily worn. For this reason, a large suction force is required.
(Blade 100) is likely to vibrate and noise is also likely to occur.
Further, since the grease 111 is used as a lubricant, it is difficult to discharge air inside the bearing when the rotating shaft 107 is inserted, so that a large amount of air remains inside the bearing and the performance of the dynamic pressure bearing is reduced. It is easy to increase the torque.

[0004]

SUMMARY OF THE INVENTION Claims 1 and 2
The described invention has an object to provide a low-cost fan motor which has excellent performance and durability, is easy to process, has a small number of parts, is easy to assemble, and has a low cost.

The third object of the present invention is to provide a fan motor capable of supporting a thrust load acting as a reaction force of a blade with a simple structure.

[0006]

[MEANS FOR SOLVING THE PROBLEMS]
Radial dynamic pressure bearing part having a groove for dynamic pressure generation on the inner surface of the cylindrical part by injection molding, and a radial and thrust integrated resin dynamic pressure bearing provided with a thrust bearing part on the bottom part of the cylindrical part connected to it, An object of the present invention is to provide a fan motor including a fan motor bearing device in which a stator is directly provided on an outer diameter surface of a sleeve outer diameter portion of a radial dynamic pressure bearing portion. Therefore, processing is easy, the number of parts is small, and assembly is easy, so that cost can be reduced. Further, the structure of the case for mounting the bearing device can be simplified.

A second aspect of the present invention is a radial dynamic pressure bearing in which the bearing of the fan motor and the case of the fan motor are integrally formed by synthetic resin, and a groove for generating dynamic pressure is formed on the inner surface of the cylindrical portion of the bearing. Part and a cylindrical thrust bearing connected to the bottom of the cylindrical part were provided with a radial and thrust integrated resin dynamic pressure bearing, and a stator was directly provided on the outer diameter surface of the outer diameter part of the radial dynamic pressure bearing part. This makes it possible to reduce the cost because of excellent performance and durability, easy processing, small number of parts, and easy assembly. Furthermore, since the case and the bearing are formed as an integral molded product made of resin, the axial dimension can be reduced, so that the case (bearing) can be made compact (thin). In the invention described in claim 1 or claim 2, the number of the radial dynamic pressure bearings is not limited to the radial dynamic pressure bearing portion. Therefore, the number of grooves for generating dynamic pressure may be one.

Conventionally, a cylindrical member for mounting the stator is provided so as to face the outer diameter surface of the sleeve outer diameter portion or the outer diameter portion of the radial dynamic pressure bearing portion. For example, a stator is attached to an outer diameter portion (cylindrical member) of a case or the like. Therefore, the fan motor had to be large as a whole device. According to the first or second aspect of the present invention, the stator is directly provided on the outer diameter surface of the sleeve outer diameter portion or the outer diameter surface of the radial dynamic pressure bearing portion. Therefore, a member (for example, a cylindrical member) for attaching the stator can be omitted, and the whole apparatus can be made compact.

More specifically, the invention according to claim 1 is a rotating shaft having a blade and a rotor fixed at one end via a support member and having a free end at the other end, and a stator opposed to the rotor at an outer peripheral portion. And a substantially cylindrical sleeve in which the rotating shaft is fitted at a substantially central portion with a gap therebetween to form a dynamic pressure bearing together with the rotating shaft, and rotatably supports the blades and the rotor. In a fan motor including a dynamic pressure bearing device for a fan motor, the sleeve is provided with a radial dynamic pressure bearing portion having a groove for generating dynamic pressure on an inner surface of a cylindrical portion, and a thrust bearing portion on a bottom surface of the cylindrical portion connected to the sleeve. It is an object of the present invention to provide a fan motor comprising a dynamic pressure bearing made of resin integrated with radial and thrust, wherein a stator is directly provided on an outer diameter surface of an outer diameter portion of the sleeve.

[0010] More specifically, the invention according to claim 2 is characterized in that the blade and the rotor are fixed at one end via a support member and the other end is a free end, and the outer periphery is opposed to the rotor. And a fan motor that rotatably supports the blades and the rotor, the stator comprising a case in which a dynamic pressure bearing portion in which the rotating shaft is inserted with a gap therebetween is provided at a substantially central portion. A case and the bearing portion are formed of an integrally molded product made of a synthetic resin, the bearing portion has a radial dynamic pressure bearing portion having a groove for generating dynamic pressure on the inner surface of the cylindrical portion;
A thrust dynamic pressure bearing portion is provided on the bottom surface of the cylindrical portion connected thereto, and a stator is provided directly on an outer diameter surface of an outer diameter portion of the radial dynamic pressure bearing portion. is there.

According to a third aspect of the present invention, there is provided a structure for forming a groove pattern in which a reaction force acting in an axial direction opposite to the thrust of the blade is generated. Here, the groove pattern is a pattern of a groove for generating a dynamic pressure. In other words, according to the third aspect of the invention, the groove pattern generates a force acting in the direction opposite to the thrust of the blade in the axial direction, and one of the free end of the rotating shaft and the thrust bearing surface is spherical, It is characterized by using oil as an agent.

Further, a radially acting support and a force acting in the axial direction opposite to the thrust of the blade can be generated by the groove pattern. Therefore, there is no need to largely shift the stator and the rotor in the axial direction. At the same time, the entire fan motor can be made compact. More specifically, the width of the groove pattern is set such that the entire width on the lower side is wider than the entire width on the upper side. In addition, by using a resin-made dynamic pressure bearing with radial and thrust, one of the end surface of the rotating shaft and the thrust bearing surface is made spherical to receive the thrust load by point contact, so that the shaft is low friction. The edge does not damage the thrust bearing surface.
As a structure, a convex spherical surface is provided on the thrust bearing surface, which is the bottom surface of the substantially cylindrical sleeve, to support the end surface of the rotating shaft, or a convex spherical surface is provided on the end surface of the rotating shaft,
The structure is supported by the thrust bearing surface of the thrust bearing portion. Furthermore, because the radial dynamic pressure bearing is also made of resin,
When starting (when starting and stopping, the shaft and sleeve inner diameter are in contact)
The friction resistance of the bearing can be reduced, and the overall bearing has low friction and excellent wear resistance. In addition, since oil is used as the lubricant, the air inside the bearing is easily discharged when the shaft is inserted, so that almost no air remains inside the bearing, and the performance of the dynamic pressure bearing does not decrease. Further, the torque is smaller than when grease is used as the lubricant.

As a structure, the groove for generating the dynamic pressure may be formed on the outer peripheral surface of the rotary shaft without being formed on the inner surface of the cylindrical portion of the bearing or the sleeve. In this case, when a groove for generating dynamic pressure is provided on the outer peripheral surface of the rotating shaft according to the first aspect of the present invention, the rotating shaft has a blade and a rotor fixed at one end via a support member, and the other end is a free end. An outer peripheral portion is provided with a stator facing the rotor, and a substantially cylindrical sleeve in which a rotating shaft is fitted at a substantially central portion with a gap therebetween to form a dynamic pressure bearing together with the rotating shaft, In a fan motor including a dynamic pressure bearing device for a fan motor rotatably supporting the blades and a rotor, a radial inner surface of a cylindrical portion of the sleeve facing a dynamic pressure generating groove provided on an outer peripheral surface of the rotating shaft. It consists of a radial and thrust integrated resin dynamic pressure bearing provided with a dynamic pressure bearing part and a thrust bearing part on the bottom of the cylindrical part connected to it, and a stator is directly mounted on the outer diameter surface of the outer diameter part of the sleeve. Provided A fan motor, wherein the door.

Similarly, when a groove for generating dynamic pressure is provided on the outer peripheral surface of the rotating shaft in the second aspect of the invention, the blade and the rotor are fixed at one end via a support member and the other end is a free end. A rotating shaft, a stator facing the rotor at an outer peripheral portion thereof, and a dynamic pressure bearing portion into which the rotating shaft is fitted with a gap provided at a substantially central portion thereof; Wherein the case and the bearing are integrally formed of synthetic resin, and the cylinder of the bearing is opposed to a groove for generating dynamic pressure provided on an outer peripheral surface of the rotating shaft. A radial dynamic pressure bearing portion on the inner surface and a thrust bearing portion provided on the bottom surface of the cylindrical portion connected thereto, and a stator is directly provided on an outer diameter surface of an outer diameter portion of the radial dynamic pressure bearing portion. Fan motor.

According to the third aspect of the present invention, if a groove for generating dynamic pressure is provided on the outer peripheral surface of the rotating shaft, the groove for generating dynamic pressure of the rotating shaft is axially opposite to the thrust of the blade. A groove pattern that generates a force acting on one of the free end of the rotating shaft and the thrust bearing surface is a spherical surface,
The fan motor according to claim 1 or 2, further comprising a fan motor dynamic pressure bearing using oil as a lubricant.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a sectional view of a fan motor according to a first embodiment of the present invention (a groove for generating a dynamic pressure in a bearing portion is omitted). FIG. 1 (2) is a cross-sectional view of the dynamic pressure bearing portion (resin dynamic pressure bearing integrated with radial and thrust) of the first embodiment of the present invention. The plurality of blades 1 are fixed to the outer peripheral portion of the support member 6 at a constant interval in the circumferential direction, and the rotor 2 is fixed to the inner peripheral portion of the support member 6. A flange 8d is provided below the outer diameter of the substantially cylindrical sleeve 8, and the flange 8d and the case 9 are fixed by press fitting or the like. A step portion 8c is provided on the outer diameter surface of the outer diameter portion of the substantially cylindrical sleeve 8. The stator 5 is positioned by the step 8c, and the substantially cylindrical sleeve 8
The stator 5 is provided directly on the outer diameter surface of the outer diameter portion.
A rotating shaft 7 having one end to which the blade 1 and the rotor 2 are fixed via a support member 6 is rotatably fitted in a substantially cylindrical sleeve 8 via a support member 6 so as to be rotatable with a certain gap therebetween and to be freely inserted and removed. . Thus, the substantially cylindrical sleeve 8 has a radial dynamic pressure bearing portion (two radial dynamic pressure bearings 11) having a dynamic pressure generating groove 8b on the inner surface of the cylindrical portion, and a thrust bearing portion 10 on the bottom surface of the cylindrical portion connected thereto. And a resin-made dynamic pressure bearing integrated with radial and thrust. With this structure, the rotor 2 and the stator 5 face each other,
It is rotatably supported around the stator 5 via a dynamic pressure bearing. The bearing gap formed by a resin-made dynamic pressure bearing integrated with the rotating shaft 7 and the radial and thrust is filled with oil 4 as a lubricant.

The rotor 2 rotates in the direction indicated by the arrow a in the figure by the rotating magnetic field generated by the stator 5, and blows in the direction indicated by the arrow b by the blades 1 provided on the outer periphery thereof. During this rotation, a pressure is generated in the oil 4 by a groove (not shown) for generating dynamic pressure on the inner diameter surface of the substantially cylindrical sleeve 8, and the oil 4 is supported in the radial direction.
And rotate without contact. The thrust load (arrow c in the drawing) acting on the rotating shaft 7 as a reaction force of the blowing action of the blade 1 at the time of blowing air is generated by the blade 1b generated by the dynamic pressure generating groove 8b.
Supported by the dynamic pressure opposite to the thrust.

Next, a specific structure for supporting a thrust load will be described. In FIG. 1 (2), the center of the thrust bearing surface 8e provided at the bottom is a convex spherical surface 8a. The width of two dynamic pressure generating grooves 8b provided on the inner diameter surface is A <
B and C <D, and the width of the two grooves is lower on the lower side than on the upper side. Accordingly, the entire width on the lower side is wider than the entire width on the upper side, and the relation of A + C <B + D is satisfied.
When the rotating shaft 7 to which the rotor 2 is fixed 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 groove 8b for generating dynamic pressure and the dynamic pressure opposite to the thrust of the blade 1 (rotating shaft) The thrust force is a force that presses the thrust bearing 7 toward the thrust bearing portion 10). The groove 8 for generating dynamic pressure
The thrust load obtained by subtracting the thrust of the blade from the thrust force generated by b is applied to the end face of the rotating shaft 7 and the thrust bearing 10.
In the point contact with the convex spherical surface 8a of the thrust bearing surface 8e.
The thrust of the blade increases as the rotation speed increases, but the dynamic pressure also increases as the rotation speed increases, so that the thrust load is hardly affected by the rotation speed. As described above, the radial dynamic pressure bearing portion (two radial dynamic pressure bearings 11) having the groove 8b for generating dynamic pressure on the inner surface of the cylindrical portion by injection molding.
And a thrust bearing portion 10 provided on the bottom surface of the cylindrical portion connected thereto. This is a radial-thrust integrated resin dynamic pressure bearing, and a groove 8b for generating dynamic pressure can also be provided at the time of injection molding. Processing is easy, the number of parts is small, and assembly is easy, resulting in low cost.

In addition, since the stator 5 is provided directly on the outer diameter surface of the outer diameter portion of the substantially cylindrical sleeve 8, the number of parts is small, the assembly is easy, and the structure of the case 9 for mounting the bearing device is simple. Cost. Further, a groove 8b for generating dynamic pressure provided on the inner surface of the cylindrical portion of the sleeve 8 having a substantially cylindrical shape.
By using the groove 8b for generating dynamic pressure, which can generate a force acting in the axial direction opposite to the thrust of the blade in the radial direction and the thrust of the blade, the structure is simple and the axial dimension can be reduced. Compact (thin). Further, since there is no need to shift the stator 5 and the rotor 2 largely in the axial direction, there is no generation of noise or the like. In addition, since it is made of a resin made of radial and thrust, one of the end surface of the rotating shaft 7 and the thrust bearing surface 8b is made spherical and receives a thrust load by point contact. The edge does not damage the thrust bearing surface 8e. Furthermore, since the radial dynamic pressure bearings (two radial dynamic bearings 11) are also made of resin, the frictional resistance at the time of startup (the shaft and the sleeve inner diameter come into contact at the time of startup and stop) can be reduced, and the entire bearing can be reduced. Low friction and excellent wear resistance. Further, since the oil 4 is used as the lubricant, the air inside the bearing is easily discharged when the rotating shaft 7 is inserted, so that almost no air remains in the bearing and the performance as the dynamic pressure bearing does not decrease. . Further, the torque can be reduced as compared with the case where grease is used as the lubricating oil.

(Second Embodiment) FIG. 2A is a sectional view of a fan motor according to a second embodiment of the present invention (a groove for generating a dynamic pressure in a bearing portion is omitted). FIG. 2 (2) is a dynamic pressure bearing portion (radial / thrust integrated resin dynamic pressure bearing) of a second embodiment of the present invention.
FIG. The second embodiment is basically the same in configuration and operation as the first embodiment. However, the means for fixing the substantially cylindrical sleeve 18 to the case 19 is different. As shown in FIG. 2A, the sleeve 18 has a substantially cylindrical shape.
Is fixed to the case 19 by fixing the sleeve flange 18b to the case 19 with the screw 13. for that reason,
The flange 18b is stronger than the press fitting in the first embodiment.
Can be fixed to the case 19. In the second embodiment, a recess 19a for receiving the flange 18b is provided in the case 19. Screw 13 is provided in flange 18d and concave portion 19a.
Are provided with screw holes 18d and 19b. Insert the flange 18b into the recess 19a,
8d is aligned with the screw hole 19b, and the screw 13 is incorporated therein. Although four (not shown) screws are used in the present embodiment, the number of screws is not particularly limited.
Further, in this embodiment, the screw is incorporated from above the flange 18d, but it is also possible to incorporate the screw from below the case 19 in consideration of the workability of the assembly. Further, the sleeve 18 having a substantially cylindrical shape can be stopped by a self-tap with a straight hole.

The width of the dynamic pressure generating groove 18b shown in FIG. 2B is A <B, C = D, which is different from the groove width ratio of the first embodiment, but is similar to that of the first embodiment. In the second embodiment, A +
The relationship of C <B + D holds. That is, the entire lower width is wider than the entire upper width. Therefore, when the rotating shaft 7 to which the rotor 2 of FIG. 2 (2) is fixed rotates in the direction indicated by the arrow a in the figure, the dynamic pressure for supporting the rotating shaft 7 in the radial direction by the groove 18b for generating dynamic pressure and the blade 1 A dynamic pressure (thrust force, which is a force pressing the rotating shaft 7 toward the thrust bearing portion 21), which is opposite to the thrust, is generated. Therefore, the rotating shaft 7 to which the rotor 2 is fixed does not float. The thrust load, which is obtained by subtracting the thrust of the blade from the thrust force generated by the dynamic pressure generating groove 18b, is received in point contact with the end surface of the rotating shaft 7 and the convex spherical surface 18a of the thrust bearing surface 18e of the thrust bearing portion 21. Other functions and effects are the same as those of the first embodiment.

(Third Embodiment) FIG. 3A is a sectional view of a fan motor according to a third embodiment of the present invention (a groove for generating a dynamic pressure in a bearing portion is omitted). FIG. 3 (2) is a dynamic pressure bearing portion (radial / thrust integrated resin dynamic pressure bearing) of a third embodiment of the present invention.
FIG. The third embodiment is basically the same in configuration and operation as the first embodiment. The difference from the first embodiment is that a substantially cylindrical sleeve 28 is inserted from below the case 29 and fixed to the case 29 at the upper surface and the outer diameter surface of the substantially cylindrical sleeve 28. Flange 2 on case 29
A lower recess 29b into which a substantially cylindrical sleeve 28 having 8d can be inserted is provided. The lower concave portion 29b has an inverted T-shape so that a substantially cylindrical sleeve 28 can be inserted. The sleeve 28 having a substantially cylindrical shape is inserted into the lower concave portion 29b by a means such as press fitting. Thus, the first embodiment has an advantage that the case 29 and the substantially cylindrical sleeve 28 can be firmly fixed. In particular, since the fan motor has a substantially cylindrical sleeve 28 sandwiched between the member to stop the bottom surface of the fan member, the case 29 and the substantially cylindrical sleeve 28 are attached when the fan motor is mounted on the partner member. Becomes firmer.

The width of the dynamic pressure generating groove 28b shown in FIG. 3B is A <B, C> D, which is different from the groove width ratio of the first embodiment and the second embodiment. The relationship of A + C <B + D holds as in the embodiment and the second embodiment. That is, the entire lower width is wider than the entire upper width. When the rotating shaft 7 to which the rotor 2 is fixed in FIG. 3 (2) 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 groove 28b for generating dynamic pressure and the thrust of the blade are opposite to the dynamic pressure. A dynamic pressure (a thrust force which is a force pressing the shaft toward the thrust bearing portion 23) is generated. Therefore, the rotating shaft 7 to which the rotor 2 is fixed
Will not surface. The thrust load obtained by subtracting the thrust of the blade from the thrust force generated by the dynamic pressure generating groove 28b is received in point contact with the end surface of the rotary shaft 7 and the convex spherical surface 28a of the thrust bearing surface 28e of the thrust bearing portion 23. Other functions and effects are the same as those of the first embodiment.

(Fourth Embodiment) FIG. 4A is a sectional view of a fan motor according to a fourth embodiment of the present invention. FIG. 4 (2) is a cross-sectional view of a dynamic pressure bearing portion (resin dynamic pressure bearing integrated with radial and thrust) according to a fourth embodiment of the present invention. FIG. 5A is a cross-sectional view of a modified example of the bearing portion (dynamic pressure bearing) of the fourth embodiment.
FIG. 5B is a cross-sectional view of another modification of the bearing portion (dynamic pressure bearing) of the fourth embodiment. The case of the fan motor and the bearing part 38 are made of an integrally molded product made of synthetic resin. The bearing portion 38 includes a radial dynamic pressure bearing portion (two radial dynamic pressure bearings 24) having a groove 38b for generating dynamic pressure on the inner surface of the cylindrical portion.
A thrust bearing 25 having a convex spherical surface on the bottom surface of the cylindrical portion connected thereto is provided. This constitutes a resin dynamic pressure bearing integrated with the radial and thrust. Bearing part 38
Is provided with a step 38c. This step 38c
And the stator 5 is provided directly on the outer diameter surface of the outer diameter portion of the radial dynamic pressure bearing portion of the bearing portion 38 (two radial dynamic pressure bearings 24). A rotary shaft 7 having the blade 1 and the rotor 2 fixed to one end thereof via a support member 6 is inserted into the bearing portion 38 so as to be rotatable with a certain gap in the radial direction and freely inserted and removed. Oil 4 is filled as a lubricant in a bearing gap formed by a resin dynamic pressure bearing integrally formed with the rotating shaft 7 and the radial and thrust bearings. The rotor 2 is rotatably supported around the stator 5 via a dynamic pressure bearing. As shown in FIG. 4B, the thrust bearing 25 provided at the bottom of the bearing 38
Is a convex spherical surface, and the width of the dynamic pressure generating groove 38b in FIG. 4 (2) is A <B, C <D, and the width of the two grooves is lower than the upper width. Has become. That is, the entire lower width is wider than the entire upper width. Therefore, the relationship of A + C <B + D is established as in the first to third embodiments. The rotor 2 rotates in the direction indicated by the arrow a in the figure due to the rotating magnetic field generated by the stator 5, and blows in the direction indicated by the arrow b by the blades 1 provided on the outer periphery thereof. At the time of this rotation, the grooves 3 for generating dynamic pressure on the inner diameter surface of the bearing portion 38
8b generates pressure in the oil 4 and is supported in the radial direction, so that the inner diameter of the bearing 38 and the rotating shaft 7 rotate in a non-contact manner.
The thrust load (arrow c in the figure) acting on the rotary shaft 7 as a reaction force of the air blowing action of the blade 1 at the time of air blowing has a dynamic pressure (thrust thrust) opposite to the thrust of the blade 1 generated by the dynamic pressure generating groove 38b. Force). That is, the thrust load, which is obtained by subtracting the thrust of the blade from the dynamic pressure (thrust force) generated by the dynamic pressure generating groove 38b, comes into point contact with the end surface of the rotating shaft 7 and the convex spherical surface 38a of the thrust bearing surface 38e of the thrust bearing portion 25. Will receive it. FIG. 4 (1),
The operation of the fourth embodiment has been described based on (2).
Similar operations are performed in (1) and (2).

The width of the dynamic pressure generating groove 48b of the radial dynamic pressure bearing 26 of the bearing portion 48 of FIG. 5A is A <B, C = D, and the radial of the bearing portion 58 of FIG. Dynamic pressure bearing 31
The width 58b of the groove for generating dynamic pressure is A <B, C> D,
In both cases, the relationship of A + C <B + D is established. That is, the entire lower width is wider than the entire upper width. Rotor 2
When the rotating shaft 7 to which the shaft is fixed is rotated in the direction indicated by the arrow a in the figure, the dynamic pressure for supporting the shaft in the radial direction by the grooves 48b and 58b for generating dynamic pressure and the dynamic pressure opposite to the thrust of the blade (shaft A thrust force, which is a force pressing the bearing portions 27 and 32, is generated. The groove 4 for generating dynamic pressure
The thrust load obtained by subtracting the thrust of the blade from the thrust force generated by 8b and 58b is received by the end face of the rotating shaft 7 and the convex spherical surfaces 48a and 58a of the thrust bearing surfaces 48e and 58e of the thrust bearing portions 27 and 32 by point contact. The thrust of the blade 1 increases as the rotation speed increases, but the dynamic pressure also increases as the rotation speed increases, so that the thrust load is hardly influenced by the rotation speed.

As described above, the case and the bearing of the fan motor are formed as an integrally molded product of synthetic resin by injection molding.
The bearing part is a radial and thrust integrated dynamic pressure bearing with a radial dynamic pressure bearing part with a groove for dynamic pressure generation on the inner diameter surface and a thrust bearing part on the bottom of the cylindrical part connected to it.
Since grooves for generating dynamic pressure are also provided at the time of injection molding,
Processing is easy, the number of parts is small, and assembly is easy, so that the cost can be reduced. Further, since the case and the bearing of the fan motor are formed as an integral molded product of a synthetic resin, the structure is simple and the axial dimension can be reduced, so that the fan can be made compact (thin). Further, since the stator is provided directly on the outer diameter surface of the outer diameter portion of the bearing portion, the number of parts is small, and the assembly is easy, so that the cost is low. The groove for dynamic pressure generation provided on the inner surface of the cylindrical part of the bearing part supports the radial direction, and the groove pattern can generate a force that acts in the direction opposite to the thrust of the blade in the axial direction. However, it can be made compact (thin) because it is simple and the axial dimension can be reduced. Further, since the stator 5 and the rotor 2 do not need to be largely displaced in the axial direction, there is no generation of noise or the like. Other operations and effects are the same as those of the first embodiment.

(Fifth Embodiment) FIG. 6A is a sectional view of a fan motor according to a fifth embodiment of the present invention. FIG. 6 (2) is a cross-sectional view of a dynamic pressure bearing portion (a resin dynamic pressure bearing integrated with radial and thrust) according to a fifth embodiment of the present invention. The fifth embodiment has basically the same configuration and operation as the fourth embodiment. The difference from the fourth embodiment is that a groove 68b for generating dynamic pressure of the radial dynamic pressure bearing 40 is provided in the bearing portion 68 at only one position in the axial direction. The width of the dynamic pressure generating groove 68b satisfies A <B, and the entire lower width is wider than the entire upper width of the dynamic pressure generating groove. As in the above-described embodiments, when the rotating shaft 7 to which the rotor 2 is fixed 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 68b is reduced. A dynamic pressure (a thrust force, which is a force pressing the rotating shaft 7 toward the thrust bearing portion 41), which is opposite to the thrust of the blade 1 is generated. Therefore, the rotating shaft 7 to which the rotor 2 is fixed does not float. The thrust load obtained by subtracting the thrust of the blade from the thrust force generated by the groove 68b for generating dynamic pressure is received by point contact with the end surface of the rotating shaft and the convex spherical surface 68a of the thrust bearing surface 68e in the same manner as in the structure of each embodiment. Similarly, the thrust of the blade increases as the rotation speed increases, but the dynamic pressure also increases as the rotation speed increases, so that the thrust load is hardly affected by the rotation speed. Since there is only one groove 68b for generating dynamic pressure, the dimension in the axial direction can be reduced, so that there is an advantage that it can be made more compact (thin). Other operations and effects are the same as those of the first and fourth embodiments.

In the first to fifth embodiments, the resin material of the substantially cylindrical sleeve or bearing portion is as follows.
PPS (polyphenylene sulfide resin) containing carbon fiber is used. However, this resin material is not limited, and any resin material having high strength and excellent wear resistance can be used as a resin material for a substantially cylindrical sleeve or a bearing portion. In the first to fifth embodiments, the outer diameter portion of the radial dynamic pressure bearing portion has a substantially cylindrical shape. It is not particularly limited to this,
It is also possible to make a sleeve of an irregular shape. For example,
It is also possible to take the shape of a prism other than a substantially cylinder. Even in such a case, the structure shown in each embodiment for fixing the sleeve to the case can be used to fix even a shape other than a substantially cylindrical shape. Further, the groove pattern is not limited to each embodiment, but may be any groove pattern and a groove width ratio that generate a dynamic pressure (force pressing the shaft in the thrust bearing direction) opposite to the thrust of the blade.

[0029]

According to the first or second aspect of the present invention, since the radial and thrust integral resin structure is used, low friction, high wear resistance and high performance are obtained. By eliminating the cylindrical member for attaching the stator, the number of parts is reduced, the assembly becomes easy, and the cost can be reduced.

According to the third aspect of the present invention, a force acting in the direction opposite to the thrust of the blade in the axial direction can be generated by the pattern of the groove for generating dynamic pressure, thereby reducing the axial dimension. Thus, the entire device can be made compact (thin). With this structure, there is no need to largely displace the stator and the rotor in the axial direction, and the occurrence of noise and the like can be suppressed. Further, by using oil as a lubricant, air inside the bearing can be easily discharged when the rotating shaft is inserted. for that reason,
Almost no air remains in the bearing, and the performance as a dynamic pressure bearing can be sufficiently exhibited. Since oil is used as the lubricant, the torque can be reduced as compared with the case where grease is used.

[Brief description of the drawings]

FIG. 1A is a sectional view of a fan motor according to a first embodiment of the present invention (a groove for generating a dynamic pressure in a bearing portion is omitted).
FIG. 1 (2) is a cross-sectional view of the dynamic pressure bearing portion (resin dynamic pressure bearing integrated with radial and thrust) of the first embodiment of the present invention.

FIG. 2A is a sectional view of a fan motor according to a second embodiment of the present invention (a groove for generating a dynamic pressure in a bearing portion is omitted).
FIG. 2 (2) is a cross-sectional view of a dynamic pressure bearing portion (resin dynamic pressure bearing integrated with radial and thrust) according to a second embodiment of the present invention.

FIG. 3A is a sectional view of a fan motor according to a third embodiment of the present invention (a groove for generating a dynamic pressure in a bearing portion is omitted).
FIG. 3 (2) is a cross-sectional view of a dynamic pressure bearing portion (resin dynamic pressure bearing integrated with radial and thrust) according to a third embodiment of the present invention.

FIG. 4A is a sectional view of a fan motor according to a fourth embodiment of the present invention. FIG. 4 (2) is a dynamic pressure bearing portion (radial / thrust integrated resin dynamic pressure bearing) of a fourth embodiment of the present invention.
FIG.

FIG. 5 (1) is a bearing section (dynamic pressure bearing) of a fourth embodiment.
It is sectional drawing of the modification of. FIG. 5B is a cross-sectional view of another modification of the bearing unit (dynamic pressure bearing) of the fourth embodiment.

FIG. 6A is a sectional view of a fan motor according to a fifth embodiment of the present invention. FIG. 6 (2) is a dynamic pressure bearing portion (a resin dynamic pressure bearing integrated with radial and thrust) according to a fifth embodiment of the present invention.
FIG.

FIG. 7 is a sectional view of a conventional hydrodynamic bearing device for a fan motor.

[Explanation of symbols]

 Reference Signs List 1 blade 2 rotor 3 magnet 4 oil 5 stator 6 support member 7 rotating shaft 8 substantially cylindrical sleeve 8a convex spherical surface 8b groove for generating dynamic pressure 9 case 38 bearing portion

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H02K 7/14 H02K 7/14 A 21/22 21/22 MF Term (Reference) 3J011 AA04 AA10 AA20 BA04 BA10 CA02 DA02 JA02 KA02 KA03 SC01 5H607 AA00 AA04 BB09 BB14 CC01 CC09 DD03 DD16 GG01 GG02 GG12 5H621 GA01 HH01 JK01 JK13

Claims (3)

[Claims] A rotating shaft having one end fixed to a blade and a rotor via a support member and the other end being a free end; a stator facing the rotor at an outer peripheral portion; A fan motor comprising a substantially cylindrical sleeve whose shaft is fitted with a gap therebetween to form a dynamic pressure bearing together with the rotating shaft, the dynamic motor bearing device for a fan motor rotatably supporting the blades and the rotor; In the above, the sleeve is a radial-thrust integrated resin dynamic pressure bearing provided with a radial dynamic pressure bearing portion having a groove for generating dynamic pressure on an inner surface of a cylindrical portion, and a thrust bearing portion connected to the bottom surface of the cylindrical portion. And a stator provided directly on an outer diameter surface of an outer diameter portion of the sleeve. 2. A rotating shaft having a blade and a rotor fixed at one end via a support member and having a free end at the other end, and a stator facing the rotor at an outer peripheral portion. The fan motor includes a case in which a dynamic pressure bearing portion in which a shaft is inserted with a gap therebetween is disposed, and the fan motor rotatably supports the blades and the rotor. The bearing portion is provided with a radial dynamic pressure bearing portion having a groove for generating dynamic pressure on the inner surface of the cylindrical portion, and a thrust bearing portion on the bottom surface of the cylindrical portion connected to the bearing, and an outer diameter portion of the radial dynamic pressure bearing portion is provided. A fan motor characterized in that a stator is directly provided on an outer diameter surface. 3. The groove for generating a dynamic pressure on the inner surface of the cylindrical portion is a groove pattern for generating a force acting in a direction opposite to the thrust of the blade in an axial direction, the free end of the rotating shaft and the thrust bearing. 3. The fan motor according to claim 1, wherein one of the surfaces is a spherical surface, and includes a dynamic pressure bearing for a fan motor using oil as a lubricant.