JPH10339318A - Dynamic pressure bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably support a spindle member in an axial direction and a diameter direction with a dynamic pressure groove formed on a nearly conical surface by forming the groove for generating dynamic pressure so as to generate peak of dynamic pressure at a plurality of positions of the axial direction. SOLUTION: A conical part 1 is provided with first bending dynamic pressure grooves 6 bent in a circumferential direction on the large diameter side of the outer peripheral surface 1c of the conical part 1, and second bending dynamic pressure grooves 7 bent in a circumferential direction on the small diameter side of the outer peripheral surface 1c. The first and second bending dynamic pressure grooves 6, 7 are arranged in parallel with each other at a prescribed clearances. In the conical part 1, peak of dynamic pressure generated by rotation of a spindle member 3 are generated in the vicinity of an angle 6a of the first bending dynamic pressure groove 6 and in the vicinity of the angle 7a of the second bending dynamic pressure groove 7. Since two dynamic pressure peaks are generated on positions which are separated for a prescribed distance from each other in the axial direction, resistance force against a moment load is enlarged so as to stably support the spindle member 3. It is thus possible to prevent oscillation of the spindle member caused by external disturbance on rotating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing for supporting a shaft member in an axial direction and a radial direction by a dynamic pressure groove formed on a substantially conical surface.

[0002]

2. Description of the Related Art Conventionally, as a dynamic bearing of this type, FIG.
As shown in the figure, a tip 52 having a conical outer peripheral surface 51
And a bearing member 56 having a conical inner peripheral surface 55 facing the outer peripheral surface 51 of the shaft member 53. The outer peripheral surface 51 of the shaft member 53 is bent in a V-shape. A plurality of dynamic pressure grooves 57 are formed in a line in the circumferential direction.

In this dynamic pressure bearing, when the shaft member 53 rotates in the direction of the arrow 58, the dynamic pressure groove 57 sends the lubricating fluid toward the apex 57A of the dynamic pressure groove 57 to generate dynamic pressure. . Therefore, the peak of the dynamic pressure is generated near the top of the dynamic pressure groove 57. With this dynamic pressure, the shaft member 53 is rotatably supported by the bearing member 56.

[0004]

However, in the above-described conventional dynamic pressure bearing, the peak of the dynamic pressure is increased by the apex 57A of the dynamic pressure groove 57.
Therefore, there is a problem in that the resistance to the moment load is small, and the shaft member 53 is likely to swing due to disturbance. In particular, in the case of high-speed rotation, there is a problem that the swinging causes contact and seizure between the shaft member 53 and the bearing member 56.

Accordingly, an object of the present invention is to provide a dynamic pressure bearing which has a large resistance to a moment load and can stably support a shaft member in an axial direction and a radial direction by a dynamic pressure groove formed in a substantially conical surface. Is to provide.

[0006]

According to a first aspect of the present invention, there is provided a dynamic pressure bearing comprising: a shaft member having a substantially conical outer peripheral surface; and a substantially conical shaft facing the outer peripheral surface of the shaft member. A bearing member having an inner peripheral surface of a shape, wherein a dynamic pressure generating groove is formed in at least one of the outer peripheral surface of the shaft member and the inner peripheral surface of the bearing member. The pressure generating groove is characterized in that it is formed so as to generate dynamic pressure peaks at a plurality of locations in the axial direction.

According to the first aspect of the present invention, the dynamic pressure generating grooves generate dynamic pressure peaks at a plurality of positions in the axial direction. Therefore, the shaft member is provided with the plurality of dynamic pressure peaks. At least two points are supported on the bearing member. Therefore, the resistance to the moment load is large and the support of the shaft member can be stabilized, and the swing of the shaft member due to disturbance during rotation is prevented,
Contact and burn-in can be prevented beforehand.

According to a second aspect of the present invention, in the dynamic pressure bearing according to the first aspect, at least one of the substantially conical outer peripheral surface and the substantially conical inner peripheral surface is formed on a large diameter side,
A first bending dynamic pressure groove bent in the circumferential direction, and a second bending dynamic pressure groove formed in at least one of the small diameter sides of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface and bent in the circumferential direction. Wherein the axial dimension of the second bending dynamic pressure groove is larger than the axial dimension of the first bending dynamic pressure groove.

According to a second aspect of the present invention, the first bending dynamic pressure groove generates a peak of dynamic pressure near the bending angle, and the second bending dynamic pressure groove moves near the bending angle. Generates a pressure peak. Therefore, since the shaft member can be supported by two dynamic pressure peaks separated in the axial direction, the resistance to the moment load is large, and the support of the shaft member can be stabilized.

In the invention of claim 2, the axial dimension of the second dynamic pressure generating groove on the small diameter side is made larger than the axial dimension of the first dynamic pressure generating groove on the large diameter side. The pressure peak can be equalized, and the swinging of the shaft member can be more reliably prevented.

According to a third aspect of the present invention, in the dynamic pressure bearing according to the first aspect, at least one of the substantially conical outer peripheral surface and the substantially conical inner peripheral surface is formed on a large diameter side,
A first inclined dynamic pressure groove inclined upward in the rotation direction so as to pump the lubricating fluid toward the small diameter side, and a small diameter of at least one of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface; A second inclined dynamic pressure groove formed on the side and inclined upward in the rotational direction so as to pump the lubricating fluid toward the small diameter side, wherein the axial dimension of the second inclined dynamic pressure groove is It is characterized in that it is larger than the axial dimension of the first forward inclined dynamic pressure groove.

According to the third aspect of the present invention, the large-diameter first inclined dynamic pressure groove generates a peak of dynamic pressure near its small-diameter end, and the small-diameter second inclined dynamic pressure groove has a small-diameter end. A peak of dynamic pressure is generated in the vicinity. Therefore, since the shaft member can be supported by two dynamic pressure peaks separated in the axial direction, the resistance to the moment load is large, and the support of the shaft member can be stabilized.

According to the third aspect of the present invention, the axial dimension of the second inclined dynamic pressure groove on the small diameter side is made larger than the axial dimension of the first inclined dynamic pressure groove on the large diameter side. The pressure peak can be equalized, and the swinging of the shaft member can be more reliably prevented.

According to a fourth aspect of the present invention, in the dynamic pressure bearing according to the first aspect, at least one of the substantially conical outer peripheral surface and the substantially conical inner peripheral surface is formed on a large diameter side,
A first inclined dynamic pressure groove inclined downward in the rotation direction so as to pump the lubricating fluid toward the large diameter side, and at least one of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface; A second inclined dynamic pressure groove formed on the small diameter side and inclined upward in the rotational direction so as to pump the lubricating fluid toward the small diameter side, wherein an axial dimension of the second inclined dynamic pressure groove is reduced. It is characterized in that it is larger than the axial dimension of the first inclined dynamic pressure groove.

According to a fourth aspect of the present invention, the first inclined dynamic pressure groove on the large diameter side generates a dynamic pressure peak near the large diameter end, and the second inclined dynamic pressure groove on the small diameter side has the small diameter. A peak of dynamic pressure is generated near the end. Therefore, the shaft member can be supported by two dynamic pressure peaks which are largely separated from each other at the axially opposite ends of the substantially conical inner or outer peripheral surface, so that a particularly large resistance force against a moment load can be obtained. In addition, the support of the shaft member can be particularly stabilized.

Further, according to the present invention, the axial dimension of the second inclined dynamic pressure groove on the small diameter side is made larger than the axial dimension of the first inclined dynamic pressure groove on the large diameter side. The pressure peak can be equalized, and the swinging of the shaft member can be more reliably prevented.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

[First Embodiment] FIG. 1 shows a first embodiment of a dynamic pressure bearing according to the present invention. In the first embodiment, a conical portion 1 having an inverted conical shape and having a small diameter side bottom end 1a is provided.
And a shaft 2 extending axially from the center of the large diameter upper surface 1b of the conical portion 1. Further, this embodiment includes a bearing member 5 having a substantially conical inner peripheral surface 5c facing the outer peripheral surface 1c of the conical portion 1. The bearing member 5 has a large-diameter upper opening 5b and a small-diameter lower opening 5a.

The conical portion 1 of the shaft member 3 has an outer peripheral surface 1
The first bending dynamic pressure grooves 6, 6, which are bent in the circumferential direction to the large diameter side of c.
6 ... On the small diameter side of the outer peripheral surface 1c of the conical portion 1, there are second bending dynamic pressure grooves 7, 7, ... which are bent in the circumferential direction. The first bending dynamic pressure groove 6 and the second bending dynamic pressure groove 7
It is arranged in two rows with a predetermined dimension in the axial direction, and plural pieces are arranged in the circumferential direction. The axial dimension of the second bending dynamic pressure groove 7 on the smaller diameter side was made larger than the axial dimension of the first bending dynamic pressure groove 6 on the larger diameter side.

In the first embodiment, when the shaft member 3 rotates in the direction of the arrow 10, the first bending dynamic pressure groove 6 and the second bending dynamic pressure groove 6 formed on the outer peripheral surface 1c of the conical portion 1 of the shaft member 3 are formed. The dynamic pressure groove 7 generates a dynamic pressure in the lubricating fluid between the conical portion 1 and the bearing member 5. This dynamic pressure peaks near the bending angle 6a of the first bending dynamic pressure groove 6 and near the bending angle 7a of the second bending dynamic pressure groove 7.
Have Therefore, two dynamic pressure peaks are generated at a position separated by a predetermined distance in the axial direction, so that the resistance to the moment load is reduced as compared with the case where the dynamic pressure peak is generated only at one position in the axial direction. And the shaft member 3 can be stably supported. Therefore, the shaft member 3 due to disturbance during rotation
Can be prevented, and contact and burn-in can be prevented.

The axial dimension of the second bending dynamic pressure groove 7 on the small diameter side is made larger than the axial dimension of the first bending dynamic pressure groove 6 on the large diameter side, so that the dynamic pressure peak generated on the small diameter side is increased. Since the peak and the dynamic pressure peak generated on the large diameter side are balanced, the swing of the shaft member 3 can be more reliably prevented.

[Second Embodiment] FIG. 2 shows a dynamic pressure bearing according to a second embodiment of the present invention. The second embodiment differs from the first embodiment only in the shape of the dynamic pressure groove formed in the conical portion 1 of the shaft member 3. Therefore, the shape of the dynamic pressure groove will be mainly described.

In this dynamic pressure bearing, a plurality of first inclined dynamic pressure grooves 21, 21 which are inclined upward in the rotational direction are formed on the large diameter side of the outer peripheral surface 1c of the conical portion 1 of the shaft member 3. Have been. Further, a plurality of second inclined dynamic pressure grooves 22, 22, ... which are inclined upward in the rotation direction are formed on the small diameter side of the outer peripheral surface 1c of the conical portion 1. The first inclined dynamic pressure grooves 21 and the second inclined dynamic pressure grooves 22 are formed in two rows separated by a predetermined distance in the axial direction. Also, the second side of the small diameter side
The axial dimension of the inclined dynamic pressure groove 22 was larger than the axial dimension of the first inclined dynamic pressure groove 21 on the large diameter side.

When the shaft member 3 rotates in the rotation direction indicated by the arrow 25, the dynamic pressure bearing 21 has a large-diameter first inclined dynamic pressure groove 21.
Generates a dynamic pressure peak near the small diameter end 21a, and the second inclined dynamic pressure groove 22 on the small diameter side generates a dynamic pressure peak near the small diameter end 22a. Therefore, since the shaft member 3 can be supported by two dynamic pressure peaks separated in the axial direction, the resistance to the moment load is large, the shaft member 3 can be stably supported, and the shaft member 3 is prevented from swinging. Thus, contact and seizure between the shaft member 3 and the bearing member 5 can be prevented.

[Third Embodiment] FIG. 3 shows a third embodiment of the dynamic pressure bearing of the present invention. This third embodiment is different from the first embodiment in the shape of the dynamic pressure groove formed in the conical portion 1 of the shaft member 3 and the structure of the bearing member. Therefore, the points different from the first embodiment will be mainly described.

In this dynamic pressure bearing, a plurality of first inclined dynamic pressure grooves 31 are formed on the large diameter side of the outer peripheral surface 1c of the conical portion 1 of the shaft member 3 so as to be inclined downward in the rotation direction. Have been. Further, a plurality of second inclined dynamic pressure grooves 32, 32,... Which are inclined upward in the rotation direction are formed on the small diameter side of the outer peripheral surface 1c of the conical portion 1. The first inclined dynamic pressure grooves 31 and the second inclined dynamic pressure grooves 32 are formed in two rows separated by a predetermined distance in the axial direction. Also, the second side of the small diameter side
The axial dimension of the inclined dynamic pressure groove 32 was made larger than the axial dimension of the first inclined dynamic pressure groove 31 on the large diameter side.

The bearing member 36 of the dynamic pressure bearing has an annular concave portion 37 at a substantially axial center of the substantially conical inner peripheral surface 36c, and extends radially outward from the concave portion 37 to form an outer peripheral surface. 36
It has a communication hole 38 communicating with the atmosphere at d. The recess 37 faces a flat surface 39 between the first inclined dynamic pressure groove 31 and the second inclined dynamic pressure groove 32.

When the shaft member 36 rotates in the rotation direction indicated by the arrow 34, the dynamic pressure bearing 3 has the first inclined dynamic pressure groove 3 on the large diameter side.
1 generates a dynamic pressure peak near the large diameter end 31a, and the second inclined dynamic pressure groove 32 on the small diameter side generates a dynamic pressure peak near the small diameter end 32a. Therefore, two axially separated
Since the shaft member 3 can be supported by two dynamic pressure peaks, the shaft member 3 can be stably supported, the swing of the shaft member 3 can be prevented, and the contact and seizure between the shaft member 3 and the bearing member 36 can be prevented. .

Further, since this dynamic pressure bearing can generate dynamic pressure peaks at both axial ends (the large-diameter end 31a and the small-diameter end 32a) of the outer peripheral surface 1c of the conical portion 1, two peaks can be generated. The dynamic pressure peak can be separated to the maximum in the axial direction. Therefore, the shaft member 3 can be most stably supported with a particularly large resistance to a moment load. When the lubricating fluid is diluted near the flat surface 39, the communication holes 3
From 8, a lubricating fluid is supplied to the vicinity of the flat surface 39.

In the first to third embodiments, the dynamic pressure grooves 6, 7, 21, 21 are formed on the outer peripheral surface 1c of the conical portion 1 of the shaft member 3.
Although 22, 31, 32 are formed, dynamic pressure grooves may be formed on the inner peripheral surfaces 5c, 36c of the bearing members 5, 36. In the first to third embodiments, the dynamic pressure grooves 6, 7, 21, 22, 31, 32 are formed in two rows in the axial direction. However, the dynamic pressure grooves are formed in three or more rows in the axial direction. It may be formed so that peaks of dynamic pressure are generated at three or more locations in the axial direction. Further, in the first to third embodiments, the shaft member 3 has the conical portion 1, but may have a hemispherical portion instead of the conical portion.

[0031]

As is apparent from the above description, in the dynamic pressure bearing according to the first aspect of the present invention, the dynamic pressure generating grooves generate dynamic pressure peaks at a plurality of positions in the axial direction. Can be supported at least at two points on the bearing member by a plurality of dynamic pressure peaks. Therefore, the resistance to the moment load is large, the support of the shaft member can be stabilized, the swing of the shaft member due to disturbance during rotation can be prevented, and the contact and seizure can be prevented.

Further, according to the present invention, the first bending dynamic pressure groove on the large diameter side generates a peak of dynamic pressure near the corner of its bending, and the second bending dynamic pressure groove on the small diameter side has the same. A peak of dynamic pressure is generated near the corner of bending. Therefore, since the shaft member can be supported by two dynamic pressure peaks separated in the axial direction, the resistance to the moment load is large, and the support of the shaft member can be stabilized. According to the second aspect of the present invention, since the axial dimension of the second dynamic pressure generating groove on the small diameter side is larger than the axial dimension of the first dynamic pressure generating groove on the large diameter side, two dynamic pressure generating grooves are provided. And the swing of the shaft member can be more reliably prevented.

According to a third aspect of the present invention, the large-diameter first inclined dynamic pressure groove generates a dynamic pressure peak near the small-diameter end, and the small-diameter second inclined dynamic pressure groove has the small-diameter dynamic pressure peak. A peak of dynamic pressure is generated near the end. Therefore, the shaft member can be supported by the two dynamic pressure peaks separated in the axial direction, so that the resistance to the moment load is large and the radial support of the shaft member can be stabilized. The invention of claim 3 is
Since the axial dimension of the second inclined dynamic pressure groove on the small diameter side is made larger than the axial dimension of the first inclined dynamic pressure groove on the large diameter side, the two dynamic pressure peaks can be equalized and the shaft member swings. Movement can be more reliably prevented.

According to a fourth aspect of the present invention, the large-diameter first inclined dynamic pressure groove generates a peak of dynamic pressure near the large-diameter end, and the small-diameter second inclined dynamic pressure groove generates the dynamic pressure peak. A peak of dynamic pressure is generated near the small diameter end. Therefore, the shaft member can be supported by two dynamic pressure peaks separated from each other in the axial direction of the inner peripheral surface or the outer peripheral surface of the substantially conical shape. Thus, the support of the shaft member can be particularly stabilized. In the invention of claim 4, the axial dimension of the second inclined dynamic pressure groove on the small diameter side is made larger than the axial dimension of the first inclined dynamic pressure groove on the large diameter side. And the swing of the shaft member can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a first embodiment of a dynamic pressure bearing according to the present invention.

FIG. 2 is a partial sectional view of a second embodiment of the dynamic pressure bearing of the present invention.

FIG. 3 is a partial sectional view of a third embodiment of the dynamic pressure bearing according to the present invention.

FIG. 4 is a partial sectional view of a conventional dynamic pressure bearing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Conical part, 1a ... Small diameter side bottom end, 1b ... Large diameter side upper surface, 1
c ... outer peripheral surface, 2 ... shaft, 3 ... shaft member, 5, 36 ... bearing member, 5a ... lower opening, 5b ... upper opening, 6 ... first bending dynamic pressure groove, 6a ... corner, 7 ... second bending movement Pressure groove, 7a ... corner, 10,
25: Arrow, 21, 31: First inclined dynamic pressure groove, 21a: Small diameter end, 22, 32: Second inclined dynamic pressure groove, 22a: Small diameter end,
31a: Large diameter end, 32a: Small diameter end.

Claims (4)

[Claims] A shaft member having a substantially conical outer peripheral surface; and a bearing member having a substantially conical inner peripheral surface facing the outer peripheral surface of the shaft member, wherein the outer peripheral surface of the shaft member and the bearing are provided. In a dynamic pressure bearing in which a groove for generating dynamic pressure is formed on at least one of the inner peripheral surfaces of the member, the groove for generating dynamic pressure generates peaks of dynamic pressure at a plurality of locations in the axial direction. A hydrodynamic bearing characterized in that it is formed so as to cause a dynamic pressure. 2. The dynamic pressure bearing according to claim 1, wherein the first bearing is formed on at least one of the large diameter side of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface, and is bent in the circumferential direction.
A second groove that is formed on at least one of the smaller diameter sides of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface and that is bent in the circumferential direction;
A hydrodynamic bearing comprising: a flexural dynamic pressure groove, wherein an axial dimension of the second flexural dynamic pressure groove is larger than an axial dimension of the first flexural dynamic pressure groove. 3. The dynamic pressure bearing according to claim 1, wherein the lubricating fluid is formed on at least one of the large diameter side of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface, and supplies the lubricating fluid toward the small diameter side. A first inclined dynamic pressure groove which is inclined upwardly in the rotational direction so as to be pressure-fed, and is formed on at least one of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface on the small diameter side, and on the small diameter side. A second inclined dynamic pressure groove that is inclined upward in the rotational direction so as to pump the lubricating fluid toward the rotation direction, wherein the axial dimension of the second inclined dynamic pressure groove is the axis of the first inclined dynamic pressure groove. A dynamic pressure bearing characterized in that it is larger than the dimension in the direction. 4. The hydrodynamic bearing according to claim 1, wherein the lubricating fluid is formed on at least one of the large diameter side of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface. A first inclined dynamic pressure groove that is inclined downward in the rotation direction so as to feed the pressure, and is formed on at least one of the smaller diameter side of the substantially conical outer peripheral surface or the substantially conical inner peripheral surface, and the smaller diameter side. A second inclined dynamic pressure groove which is inclined upward in the rotation direction so as to pump the lubricating fluid toward the first inclined dynamic pressure groove, wherein the axial dimension of the second inclined dynamic pressure groove is A dynamic pressure bearing having a dimension larger than an axial dimension.