JPH0823370B2 - Dynamic bearing device - Google Patents

Description

The present invention relates to an improvement of a dynamic pressure bearing device used in information equipment, audio equipment, video equipment and the like.

[Prior art and its problems]

Conventionally, as shown in FIG. 2 of Japanese Utility Model Application Laid-Open No. 60-26676, it has a bottomed cylindrical bearing member and a shaft body inserted into the cylindrical hole. The cylindrical hole of the bearing member has a thrust bearing surface and a cylindrical radial bearing surface. on the other hand,
The shaft body has a thrust surface facing the thrust bearing surface and a radial surface facing the radial bearing surface. The radial surface is provided with a spiral groove, and the thrust bearing surface is provided with an axial communication hole. The dynamic pressure bearing device is sealed by a case.

When the bearing member rotates, due to the pumping action of the spiral groove, the air in the radial bearing clearance flows from the communication hole to the outside of the bearing member, flows into the opening side of the cylindrical hole, and circulates. Rotates without contact with the shaft. When such a hydrodynamic bearing device is used at low speed rotation (about 3600 rpm) for a magnetic disk device, both the radial bearing part and the thrust bearing part are air bearings, so sufficient load capacity (especially thrust load capacity ) Is difficult to obtain. Also, during start-up / stop or low-speed rotation, the bearing member contacts the shaft body and wears them, and especially the thrust bearing surface and the thrust surface that support the load of the bearing member wear, and the wear particles of the bearing hole It is discharged from and circulates. As a result, abrasion powder may adhere to the magnetic head and impair the performance, and the circulating abrasion powder damages the radial bearing portion and the thrust bearing portion. Even when the hydrodynamic bearing device is used for other purposes, various adverse effects can be expected due to the discharge of abrasion powder.

The present invention solves the above-mentioned problems in the prior art, that is, has a sufficiently large thrust load capacity, and has less abrasion powder and the like generated at the time of start and stop, and less scattering of abrasion powder and the like to the outside of the bearing. The purpose of the invention is to provide a devised dynamic pressure bearing device.

[Means and actions for solving problems]

To achieve the above object, in the present invention, at least one of the bearing member and the shaft body is provided with a circulation path through which gas between the radial bearing clearance and the thrust bearing clearance communicates with the opening side portion of the cylindrical hole. A filter member is formed in this circulation path, and a lubricant such as oil or grease is present in the thrust bearing clearance. If you do this,
When either the bearing member or the shaft rotates, the gas flow in the radial bearing clearance causes the gas in the radial bearing clearance to circulate through the circulation path, resulting in fineness in the gas, oil mist, etc. Is absorbed by the filter member during circulation and is prevented from scattering outside the bearing device.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. This is an example in which the present invention is applied to a magnetic disc device.

In FIG. 1, the dynamic pressure bearing device is a cylindrical bearing member with a bottom.
10 and a shaft body 40 that is inserted into the cylindrical hole. The bearing member 10 is composed of a sleeve 12 and a disc member 14 that covers one opening thereof.A cylindrical radial bearing surface 16 is formed on the inner peripheral surface of the sleeve 12, and the central portion of the lower surface of the disc member 14 is formed. Has a flat thrust bearing surface 18 having a smaller diameter than the radial bearing surface 16. A pair of passages 22 and 24 that extend radially outward from the inner peripheral surface of the sleeve 12 are axially separated from each other, and both passages are connected by an axial passage 26. A circulation path is formed by the passages 22, 24 and 26, and one (upper) passage 22 is filled with a filter member 28.

A disk-shaped support member 32 having a conformal shape is fixed to the sleeve 12 and the disk member 14 with screws or the like, and a rotor support member 34 is fixed to the lower end surface of the sleeve 12 with screws or the like. An appropriate number of discs 36 are attached to the disc support member 32 at intervals in the axial direction, and a rotor 38 is supported by the rotor support member 34.

The shaft body 40 is composed of a cylindrical member 42, and a cylindrical support member 46 inserted and attached to an axially upper portion of a cylindrical hole 44 provided through the cylindrical member 42 in the axial direction. A radial surface 48 is formed on the surface facing the radial bearing surface 16, and a thrust surface 52 facing the thrust bearing surface 18 is formed on the upper end surface of the support member 46. As shown in FIG. 2, on the radial surface 48, herringbone-shaped grooves 54 are formed at two positions spaced apart in the axial direction, and the groove has a "V" shape.

In the herringbone groove 54, the axial length A above the bending point is shorter than the axial length B below the bending point, and the gas in the radial bearing clearance 59 is a herringbone groove. It is designed to flow upward by the pumping action. A circumferential groove 80 is provided at the lower end of the radial surface 48, and a circumferential groove is provided on the radial surface 48 below the circumferential groove 80.
A spiral groove 82 is provided which is connected to 80 and performs a sealing action. The groove 82 that performs a sealing action faces the radial bearing surface 16 and prevents gas from flowing out. Further, as shown in FIG. 3, a spiral dynamic pressure generating groove 56 is formed on the thrust surface 52.

The cylindrical hole 44 of the shaft body 40 is surrounded by a radial groove 58 so as to form a groove 80.
Is communicated with the radial bearing clearance 59 via a through hole, and a filter member 60 is filled in the axially intermediate portion of the cylindrical hole 44. A groove-shaped fine hole 62 extending in the axial direction is formed in the upper part of the inner peripheral surface of the cylindrical member 42, and the cylindrical hole 44 and a portion 63 between the radial bearing clearance 59 and the thrust bearing clearance are communicated with each other. . The cylindrical member 42 is fixed to a hermetically-sealed housing 66 via a substrate 64, and a stator 68 is fixed to the substrate 64 so as to face the rotor 38.

 Next, the operation and effect of this embodiment will be described.

The bearing member is formed by the interaction between the rotor 38 and the stator 68.
When 10 rotates integrally with the disk 36 and the like, the thrust bearing surface 18 rotates without contact with the thrust surface 52 due to the pumping action of the groove 56 for generating dynamic pressure, and the radial surface 48
The pumping action of the upper herringbone groove 54 causes the radial bearing surface 16 to rotate in non-contact with the radial surface 48.

In this embodiment, the thrust bearing surface 18 and the thrust surface
Lubricants such as grease and oil are present in the thrust bearing clearance between the shaft 52 and 52. Therefore, the load capacity in the thrust direction increases as compared with the conventional case where no lubricant is present in the thrust bearing clearance. Further, the wear between the thrust bearing surface 18 and the thrust surface 52 is small.

Further, in the sleeve 12 of the bearing member 10, a closed-loop-shaped passage 22, which opens to the radial bearing clearance 59 via the circumferential groove 80,
24 and 26 are formed, and radial and axial pores 58 and 62 are formed in the cylindrical member 42, and one pore 58 makes the cylindrical hole 44 and the radial bearing clearance 59 communicate with each other, and The hole 62 communicates the cylindrical hole 44 with the location 63 between the radial bearing clearance 59 and the thrust bearing clearance. Therefore, the pores 58 and 62 and the cylindrical hole 44 form a circulation path. Therefore, when the bearing member 10 rotates, a gas flow flowing upward in the radial bearing clearance 59 is generated by the action of the herringbone-shaped groove 54, and this gas flow passes through the passage 22,
The holes 24 and 26, the pores 62 and 58, and the cylindrical hole 44 are circulated toward the opening side of the cylindrical hole of the bearing member 10. At that time, since the filter members 28 and 60 are filled, the abrasion powder and the mist of the lubricant in the thrust bearing clearance, which may be generated by the contact between the bearing member 10 and the shaft body 40, ride on the gas flow. Even if it circulates, it is absorbed by the filter members 28 and 60, and it is prevented from flowing into the bearing clearance and is hardly leaked outside the dynamic pressure bearing device.

The herringbone-shaped groove formed on the radial surface 48 may have a "H" shape in which the upper portion 72a and the lower portion 72b are inclined in opposite directions as shown in FIG.

In addition, the present invention can be appropriately modified and improved within a range that does not impair the gist thereof. For example, in the dynamic pressure bearing of the type shown in the above embodiment, the herringbone-shaped groove is used.
Even if 54 and 72 are provided on the sleeve 12 of the bearing member 10,
It may be provided on both the sleeve 42 and the sleeve 12. Further, the groove 56 for generating dynamic pressure may be provided on at least one of the thrust bearing surface 18 and the thrust surface 52. In addition, the circulation paths 22, 24,
26, 44, 58, 62 may be provided on either one of the bearing member 10 and the shaft body 40. The thrust bearing surfaces 18, 52 may be curved. Furthermore, with the bearing member fixed in position,
You may make it rotate a shaft.

〔The invention's effect〕

As described above, according to the present invention, a circulation path is formed in at least one of the bearing member and the shaft body to allow gas between the radial bearing clearance and the thrust bearing clearance to flow into the opening side portion of the cylindrical hole. A lubricant is present in the thrust bearing clearance while communicating. Therefore, the thrust load capacity increases, the wear due to the contact between the thrust bearing surface and the thrust surface is small, and even if abrasion powder or the like occurs during relative rotation between the bearing member and the shaft body, it is absorbed by the filter member. Inflow into the bearing clearance and scattering of the hydrodynamic bearing to the outside are prevented. Further, scattering of the mist of the lubricant in the thrust bearing clearance is prevented, and the dynamic pressure bearing is operated in a desired state for a long period of time.

[Brief description of drawings]

FIG. 1 is a front sectional view of an embodiment of the present invention, and FIG.
FIG. 3 is a front view of a main part of the drawing, FIG. 3 is a view from the II direction in FIG. 1, and FIG. 4 is a front view showing a modified example of FIG. [Explanation of symbols of main parts] 10 …… Bearing member 16 …… Radial bearing surface 18 …… Thrust bearing surface 22, 24,26; 58,44,62 …… Circuit path 28,60 …… Filter member 40 …… Shaft 48 …… Radial surface 52 …… Thrust surface 54, 72 …… Herringbone groove 56 …… Dynamic pressure generating groove 59 …… Radial bearing clearance

Claims (1)

[Claims] 1. A dynamic pressure bearing having a bearing member having a cylindrical hole and a shaft body inserted into the cylindrical hole of the bearing member, wherein the cylindrical hole has a cylindrical radial bearing surface. A thrust bearing surface, the shaft body has a radial surface facing the radial bearing surface, and a thrust surface facing the thrust bearing surface, and at least one of the radial bearing surface and the radial surface is herringed. A hydrodynamic bearing device in which a bone-shaped groove is formed, and a groove for generating dynamic pressure is formed on at least one of the thrust bearing surface and the thrust surface, the thrust bearing between the thrust bearing surface and the thrust surface. There is a lubricant in the clearance, gas is present in the radial bearing clearance between the radial bearing surfaces and the radial surface, and there is a gap between the thrust bearing clearance and the radial bearing clearance. Of the gas communicates with the opening side of the cylindrical hole through a circulation path provided in at least one of the bearing member and the shaft body, a filter member is disposed in the circulation path, and the shaft body and the shaft body The gas between the thrust bearing clearance and the radial bearing clearance flows into the opening side portion of the cylindrical hole through a circulation path when one of the bearing member and the bearing member rotates. .