JP2002070864A - Bearing construction provided with hydrodynamic bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized bearing construction provided with a hydrodynamic bearing which needs no means having an extraction-proof property to be arranged around a peripheral portion of the bearing construction and has high reliability. SOLUTION: The bearing construction provided with a hydrodynamic bearing comprises: a bearing member 4 which is bottomed cut-shaped and has a small hole at the bottom thereof and also includes a convex arc surface in a range of a periphery of a small hole at the bottom; stepped smaller diameter section 3-11 provided at the tip portion of a formation part of a hydrodynamic pressure generation mechanism 5; and a retention mechanism 8 arranged at the outer end portion of the stepped smaller diameter section extending through the small hole of the bearing member, or a shaft member constructed so as to abut against a steel ball 7 fixedly retained in a housing after the nose portion thereof is penetrated through the small hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure having a dynamic pressure mechanism, which can be easily fitted in an assembling operation and is suitable for preventing leakage of sealed oil.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view of an essential part of an example of an axial flow fan using an outer rotor type electric motor and having a dynamic pressure bearing structure.

A cylindrical bearing box 1-1 integral with a housing 1 holds a stator 2 on an outer peripheral surface thereof, and a bearing member 4 having a bottomed cup-like oil retaining property is fitted and held on an inner peripheral surface thereof. And a rotor shaft 3-1 integrally formed with the rotor 3 is supported. On the inner peripheral surface of the bearing member 4 and the outer peripheral surface of the rotor shaft 3-1 which is in sliding contact with the bearing member 4, a lubricating oil interposed with the rolling sliding forms a thin film so as to maintain non-contact with each other. A pressure generating mechanism 5 is formed. As is well known, various improvements have been made in the structure of the dynamic pressure bearing mechanism 5 such as maintenance of reliability and improvement in accuracy of oil film formation. However, since these are accompanied by cost derivation, further improvements are required. It was the reality.

[0004]

In the conventional structure as described above, when a shaft member is inserted into a bottomed cup-shaped bearing member, oil added for forming an oil film seals the inside of the bearing member. However, although it is not shown in the drawing, it is difficult to insert and insert the shaft member. To facilitate the insertion of the shaft member, a small hole is provided on the bottom surface of the bearing member as an air escape passage. Then, naturally, there was a problem that leakage of the encapsulated lubricating oil was inevitable. Furthermore, in the configuration of the one-sided support as in this example, since the withdrawal force in the axial direction only depends on the sealing degree of the bearing structure, in practice, it is also necessary to add a means for preventing withdrawal at the outer end face or the like of the rotating body. Was needed.

[0005]

According to the present invention, there is provided a bearing structure provided with a hydrodynamic bearing according to the present invention, which has a bottomed cup shape, has a small hole in the bottom, and has an inner surface whose bottom is convex at the periphery of the small hole. A bearing member comprising: a stepped small-diameter portion is provided at the end connected to the dynamic pressure generating mechanism forming portion, and the stepped small-diameter portion has a retaining mechanism at an outer end portion that passes through the small hole of the bearing member,
Or, after the tip thereof penetrates the small hole, a shaft member configured to abut against a hard sphere fixed and held in the housing,

[0006] Alternatively, a bearing member having a bottomed cup shape, a shaft member having a small-diameter step portion at an intermediate portion connected to a dynamic pressure generating mechanism forming portion formed at an end thereof, and a molded body made of an elastic material are used. The outer peripheral edge forming an annular shape is held by the housing, and the inner circumferential arc surface of the annular shape is smaller than the outer diameter of the shaft member but larger than the small diameter portion of the step, or from the outer peripheral edge to the center. An arc surface formed by a plurality of leg portions directed toward each other is formed such that a circular arc surface formed by each tip is smaller than the outer diameter of the shaft member but larger than the small diameter portion of the step. An annular member formed with an arc diameter to be formed, the inner peripheral arc surface being fitted into and attached to a small-diameter step portion of the shaft member;

[0007] Alternatively, the bearing member having the shape of a cup with a bottom has a small hole in the center of the bottom portion, and the hard sphere fitted and held in the small hole is configured to abut the tip end surface of the shaft member. Alternatively, a small hole is provided at the center of the bottom, and a dish-shaped recess is formed at the inner end of the small hole, and the hard sphere fitted in the dish-shaped recess is configured to abut the tip end surface of the shaft member. Alternatively, a small hole is provided at the center of the bottom, and a plate-like member having a spring property is additionally provided on the inner surface of the bottom, and the spring member comes into contact with the tip surface of the shaft member to form a barrel contact, and the small hole is It is configured to also have a hard ball fitted and held,

Alternatively, the shaft member has at least one circumferential groove including a scale-like groove or a dimple groove adjacent to the dynamic pressure generating mechanism forming portion in the vicinity of the sliding contact portion with the bearing member end. It is configured as follows.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an essential part of an example of an axial fan having a bearing structure according to the present invention. Since the dynamic pressure generating mechanism formed by the inner peripheral surface of the bearing and the outer peripheral surface of the shaft member that is in sliding contact with the bearing is known in the art, detailed description thereof is omitted. FIG. 8 above
As in the prior art example shown in FIG. 1, a stator 2 of a driving motor is fitted and held on an outer peripheral surface of a cylindrical bearing box 1-1 integrally formed with a housing 1, and a bearing member is mounted on an inner peripheral surface. 4 is fixed. The bearing member 4 is similar to the above-described prior art example in that it has a bottomed cup shape.
1 is formed, and an arc-shaped projection 4-2 is formed such that the peripheral edge of the small hole 4-1 on the inner surface of the bottom forms the top. When the arc-shaped projection 4-2 comes into contact with the stepped portion of the rotor shaft 3-1 facing the arc-shaped projection 4-2 as a body contact, the arc-shaped projection 4-2 reduces the sliding contact area as a configuration similar to a pivot receiving structure by a hard ball 7 described later, and reduces friction. Reduction and rotor shaft 3-1
Since the sliding contact surface with the stepped portion is annular and has a linear shape with a small area, the airtightness is improved, so that the bearing member 4 is formed.
Of the lubricating oil from the bottom small hole 4-1.

The small-diameter portion 3 of the rotor shaft 3-1 penetrates the small hole 4-1 of the bottom surface of the cup-shaped bearing member 4 having a bottom.
-11 passes through the small hole 4-1 and then,
For example, a stopper formed by a groove formed on the shaft side and a retaining ring 8 fitted to the groove is provided to form a rotating member withdrawing preventing unit.

FIG. 2 shows a second embodiment of the bearing structure according to the present invention.
A small hole 4-1 is formed on the bottom surface of the
1 is provided with a small stepped portion 3-11 at the end thereof, and the small stepped portion 3-11 is inserted through the small hole 4-1. A pivot bearing structure for reducing rotational friction is provided by the contact between the tip of -11 and the hard ball 7 fixed to the housing 1. The function of suppressing the leakage of the lubricating oil is carried out by the hard spheres 7 that are fixed to the housing 1 so as to be pressed against the housing 1 at a position close to the bottom surface of the bearing member 4.

FIG. 3 shows a third embodiment of the bearing structure according to the present invention. By providing a small hole 4-1 on the bottom surface of the bearing member 4,
While keeping the effect of facilitating the operation of inserting the rotor shaft 3-1, the anti-extraction means is formed in a small-diameter stepped portion 3-13 formed at an intermediate portion of the rotor shaft 3-1 and the annular member 6 fitted therein.
This is an example realized in combination with. After the insertion of the rotor shaft 3-1, the hard ball 7 is pressed and fixed to the bottom small hole 4-1 of the bearing member 4, thereby realizing a body hitting structure by contact with the shaft end, and at the same time, achieving the small hole. It is configured to prevent leakage of lubricating oil due to blockade of 4-1. Referring to FIGS. 6 and 7, the annular member 6 constituting the extracting means has an annular outer peripheral edge 6-1 fixed and held, and a plurality of leg-like portions 6 provided from the center toward the center. -2,
The inner circumference arc diameter 6-3 formed by the tip of the leg-shaped portion 6-2 is
The distal end of each of the leg portions 6-2 has a diameter smaller than the outer diameter of the rotor shaft 3-1 and larger than the outer diameter of the step small diameter portion 3-13. By fitting into the small step portion 3-13, the body contact means is formed by contact with the end surface of the step portion.

FIG. 4 shows a fourth embodiment of the bearing structure according to the present invention. In the above-mentioned third embodiment, the hard sphere 7 fitted in the small hole 4-1 is only pressed into the small hole 4-1. Because it is held in
In order to further increase the fixing holding strength, a large dish-shaped concave portion 4-2 is provided inside the small hole 4-1 and the hard ball 7 is accommodated in the dish-shaped concave portion 4-2 so that the hard ball 7 is a bearing member. This is an example in which the concern of leaving from No. 4 is eliminated.

FIG. 5 shows still another fifth example, and FIG.
The body contact means which contacts the shaft end is not a hard ball itself, but a plate-like member 9 having a spring property. The hard ball 7 pressed and held in the small hole 4-1 is lubricated. It functions as oil leakage prevention means.

FIGS. 6 and 7 show the rotor shaft 3 shown in FIGS. 3 to 5 having a stepped small diameter portion 3-13 at an intermediate portion.
It is the front view and sectional view which show the example of the annular member 6 which forms a body contact structure by using together with -1. As shown in the figure, the annular member 6 is provided with a plurality of center-facing leg portions 6-2 from an outer annular peripheral portion 6-1 and an inner peripheral edge formed by a tip of the leg portion 6-2. 6-3 has a diameter smaller than the outer diameter of the rotor shaft 3-1 and larger than the outer diameter of the stepped small diameter portion 3-13. By fitting into the step small diameter portion 3-13 of the shaft 3-1, the shaft 3-1 serves as a pull-out resistant means in the axial direction. As shown in the figure, the tip of the leg 6-2 has an end shape 6 that forms a conical shape in the axial direction.
-31, thereby facilitating insertion into the rotor shaft 3-1 by utilizing the bending of the leg-shaped portion 6-2. It is needless to say that the annular member 6 may be a simple ring if it has a structure having flexibility.

In any of the above-described configurations, the small hole 4-1 provided on the bottom surface of the cup-shaped bearing member 4 having the bottom is inserted into the sealed space when the rotor shaft 3-1 is inserted into the bearing member 4. In addition to being able to eliminate repulsion due to pressure compression in the above, it can also be used as an inlet for lubricating oil to be enclosed.

Further, by providing a circumferential groove 3-12 at a position adjacent to the portion where the dynamic pressure generating mechanism 5 of the rotor shaft 3-1 is formed, leakage of the sealed oil can be prevented. -12
May be a scale-shaped groove or a dimple groove formed as a continuous body of small concave portions, in addition to the U-shaped groove continuous in the circumferential direction.

[0019]

According to the bearing structure provided with the dynamic pressure bearing according to the present invention, by providing means having withdrawal resistance inside the bearing structure, it is possible to eliminate the juxtaposition at the peripheral portion and to obtain a highly reliable small bearing structure. Has been realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an example of a bearing structure according to the present invention.

FIG. 2 is a sectional view of a main part of a second example of the bearing structure according to the present invention.

FIG. 3 is a sectional view of a main part of a third example of the bearing structure according to the present invention.

FIG. 4 is a sectional view of a main part of a fourth example of the bearing structure according to the present invention.

FIG. 5 is a sectional view of a main part of a fifth example of the bearing structure according to the present invention.

FIG. 6 is a front view of an example of an annular member used for the bearing structure according to the present invention.

FIG. 7 is a sectional view of the example of FIG. 6;

FIG. 8 is a sectional view of a main part of an example of a bearing structure according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 1-1 Bearing box 2 Stator 3 Rotor 3-1 Rotor shaft 3-11 Small step part of shaft end 3-12 Circumferential groove 3-13 Small step part of intermediate part 4 Bearing member 5 Dynamic pressure Generating mechanism 6 Annular member 7 Hard ball 8 Stop ring 9 Plate member having spring property

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 9, 2001 (2001.1.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006] Alternatively, a bearing member having a bottomed cup shape, a shaft member having a small-diameter step portion at an intermediate portion connected to a dynamic pressure generating mechanism forming portion formed at an end thereof, and a molded body made of an elastic material are used. The outer peripheral edge forming an annular shape is held by the housing, and the inner circumferential arc surface of the annular shape is smaller than the outer diameter of the shaft member but larger than the small-diameter stepped portion , or from the outer peripheral edge to the center. It has a plurality of leg-like portions facing each other, and an arc surface formed by each tip is smaller than the outer diameter of the shaft member.
An annular member that is larger than the small-diameter stepped portion , and has an arc diameter that forms a conical shape with one end in the axial direction being small and the other end being large, and the inner circumferential arc surface being fitted into the small-diameter stepped portion of the shaft member. With

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

FIG. 3 shows a third embodiment of the bearing structure according to the present invention. By providing a small hole 4-1 on the bottom surface of the bearing member 4,
While keeping the effect of facilitating the operation of inserting the rotor shaft 3-1, the anti-extraction means is formed in a small-diameter stepped portion 3-13 formed at an intermediate portion of the rotor shaft 3-1 and the annular member 6 fitted therein.
This is an example realized in combination with. After the insertion of the rotor shaft 3-1, the hard ball 7 is pressed and fixed to the bottom small hole 4-1 of the bearing member 4, thereby realizing a body hitting structure by contact with the shaft end, and at the same time, achieving the small hole. It is configured to prevent leakage of lubricating oil due to blockade of 4-1. Referring to FIGS. 6 and 7, the annular member 6 constituting the extracting means has an annular outer peripheral edge 6-1 fixed and held, and a plurality of leg-like portions 6 provided from the center toward the center. -2,
The inner circumference arc diameter 6-3 formed by the tip of the leg-shaped portion 6-2 is
The distal end of each of the leg portions 6-2 has a diameter smaller than the outer diameter of the rotor shaft 3-1 and larger than the outer diameter of the small-diameter stepped portion 3-13. Small diameter step
By fitting into the portion 3-13, the body contact means is formed by contact with the end face of the step portion.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

FIGS. 6 and 7 show the rotor shaft 3 shown in FIGS. 3 to 5 having a small-diameter stepped portion 3-13 at an intermediate portion.
It is the front view and sectional view which show the example of the annular member 6 which forms a body contact structure by using together with -1. As shown in the figure, the annular member 6 is provided with a plurality of center-facing leg portions 6-2 from an outer annular peripheral portion 6-1 and an inner peripheral edge formed by a tip of the leg portion 6-2. 6-3 has a diameter smaller than the outer diameter of the rotor shaft 3-1 and larger than the outer diameter of the small-diameter stepped portion 3-13. By fitting into the small-diameter step portion 3-13 of the shaft 3-1, the shaft 3-1 serves as a withdrawal-resistant means in the axial direction. As shown in the figure, the tip of the leg 6-2 has an end shape 6 that forms a conical shape in the axial direction.
-31, thereby facilitating insertion into the rotor shaft 3-1 by utilizing the bending of the leg-shaped portion 6-2. It is needless to say that the annular member 6 may be a simple ring if it has a structure having flexibility.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Yoshihiko Adachi, Inventor 433-2 Ururen, Uraira-cho, Naka-gun, Ibaraki Pref. MA21 3J016 AA02 AA03 BA02 BA03

Claims (11)

[Claims] 1. A bearing member fitted and held in a bearing box formed integrally with a housing, and a shaft member inserted through an inner peripheral surface of the bearing member. In the bearing structure having the bearing member, the bearing member has a bottomed cup shape and has a small hole in the bottom portion, and the shaft member has a stepped small-diameter portion provided at a tip end thereof which is connected to a dynamic pressure generating mechanism forming portion. A small diameter part penetrates a small hole of the bearing member, and has a retaining mechanism at an outer end thereof. 2. An end of the stepped small diameter portion of the shaft member end portion is configured to penetrate a small hole of the bearing member and then contact a hard ball fixed and held on the housing. A bearing structure comprising the dynamic pressure bearing according to claim 1. 3. A bearing member fitted and held in a bearing box formed integrally with a housing, and a shaft member inserted through an inner peripheral surface of the bearing member. The bearing member has a bottomed cup shape, and the shaft member has a small-diameter step portion at an intermediate portion connected to a dynamic pressure generating mechanism forming portion formed at an end thereof, and A peripheral edge is held by the housing, and an inner peripheral arc surface smaller than the outer diameter of the shaft member and larger than the small step portion is fitted into the small step portion of the shaft member. A bearing structure comprising a dynamic pressure bearing, further comprising an annular member to be mounted. 4. The circular member has a plurality of leg-shaped portions extending from the outer peripheral edge forming an annular shape toward the center, and each tip has an arc diameter smaller than the outer diameter of the shaft member and larger than the small diameter portion of the step. The bearing provided with the hydrodynamic bearing according to claim 3, further comprising: an inner peripheral arc surface having: (a) an inner peripheral arc surface fitted into the small-diameter step portion of the shaft member. Construction. 5. The annular member is a molded body made of an elastic material, and has an inner circumferential arc surface having a conical shape with one end in the axial direction being small and the other end being large. A bearing structure comprising the dynamic pressure bearing according to any one of the above. 6. The bearing member having the shape of a cup with a bottom has a small hole in the center of the bottom portion, and a hard ball fitted and held in the small hole is configured to abut on a tip end surface of the shaft member. A bearing structure comprising the dynamic pressure bearing according to any one of claims 3 to 5. 7. The bearing member having the shape of a cup with a bottom has a small hole in the center of the bottom, and a dish-shaped recess is formed at an inner end of the small hole, and is fitted into the dish-shaped recess. Hard balls are configured to contact the shaft member tip surface,
A bearing structure comprising the dynamic pressure bearing according to any one of claims 3 to 5. 8. The bearing member having the shape of a cup with a bottom has a small hole in the center of the bottom, and a plate-like member having resilience is provided on the inner surface of the bottom, and the spring member abuts on the tip end surface of the shaft member. The bearing structure according to any one of claims 3 to 5, wherein the bearing structure is configured to have a body contact and also to include a hard ball fitted and held in the small hole. . 9. The system according to claim 1, wherein the bearing member has at least one circumferential groove adjacent to a dynamic pressure generating mechanism forming portion near an end of the bearing member that is in sliding contact with the shaft member. A bearing structure comprising the dynamic pressure bearing according to any one of 1 to 8. 10. A scaly shape in which a circumferential groove formed adjacent to a dynamic pressure generating mechanism forming portion on a sliding contact surface of the shaft member with the vicinity of an edge of a bearing member is formed of small concave portions arranged in a circumferential direction. A bearing structure comprising the dynamic pressure bearing according to claim 9, wherein the bearing structure is a groove. 11. A dimple groove in which a circumferential groove formed adjacent to a dynamic pressure generating mechanism forming portion on a sliding contact surface of the shaft member with a vicinity of an end of a bearing member is formed of small concave portions arranged in a circumferential direction. A bearing structure provided with the dynamic pressure bearing according to claim 9.