JPS61290228A - Dynamic pressure fluid bearing unit - Google Patents

Abstract

PURPOSE:To provide high thrust load capacity while to shorten the axial dimension of fixed shaft by facing the thrust receiving face of rotary member against the thrust shaft receiving face of housing through lubricant filled in the gap of thrust bearing. CONSTITUTION:Rotary member 47 has a planar thrust receiving face 53 facing against the thrust shaft receiving face 43 and constructed with said thrust receiving face 53 and thrust shaft receiving face 43. The maximum diameter of thrust bearing is shorter than that of radial bearing face 61. Liquid or semi-liquid lubricant such as oil, grease will exist in the thrust bearing gap 55 between said faces 43, 53. While spiral groove 45 for producing spiral dynamic pressure is made in the thrust bearing face 43.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydrodynamic bearing device used in various fields such as office machines, video equipment, and audio equipment.

[Prior Art] As shown in FIG. 3, a rotating member 5 is fitted into a fixed shaft 3 fixed to a housing 1, and this rotating member 5 is connected to an end surface 7 of the fixed shaft.
The bottom surface 9 facing the rotating member 5 has an exhaust hole 11 that opens to the outer surface of the rotating member 5. A herringbone groove effective to support radial loads is provided at both axial ends of the fixed shaft 3, and a spiral groove effective to support thrust load is provided at the axial middle part. 13 are provided. A stator 15 attached to the housing 1
is opposed to the rotor 17 attached to the rotating member 5 with a cylindrical surface. When the rotating member 5 rotates, the lower ms of the rotating member 5 is caused by the pumping action of the spiral groove 13.
The air flowing into the radial bearing gap 19 between the rotating member 5 and the fixed shaft 3 is exhausted from the exhaust hole 11 to the outside of the rotating member 5, and the rotating member 5 rotates without contacting the fixed shaft 3.

[Problems to be Solved by the Invention] In order to obtain sufficient thrust load capacity, it is necessary to increase the axial length of the spiral groove 13, and the axial dimension of the fixed shaft 3 cannot be shortened.

In addition, in the case of a motor in which the rotor attached to the rotating member 5 and the stator attached to the housing 1 face each other on a plane, the rotor made of magnets is strongly attracted to the stator, so the thrust load becomes large, and the same dimensions are further reduced. become longer.

Furthermore, since the end surface 7 of the fixed shaft and the bottom surface 9 of the rotating member come into sliding contact without lubrication during startup and stop, the end surface 7 of the fixed shaft
and the bottom surface 9 of the rotating member are prone to wear, which poses a problem in durability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydrodynamic bearing device that can be reduced in axial dimension and has excellent durability.

Means for Solving Problem E] The planar thrust bearing surface provided on the housing faces the thrust bearing surface provided on the rotating member via a lubricant in the thrust bearing clearance, and the thrust bearing surface and the thrust bearing face each other via a lubricant in the thrust bearing clearance. A groove for generating dynamic pressure is provided on at least one side of the rotating member, and the rotating member has a cylindrical groove on the opposite side of the thrust receiving surface.
Attach the fixed shaft that fits into the cylindrical hole to the housing,
The cylindrical radial sleeve bearing surface provided on the fixed shaft faces the radial bearing surface provided in the cylindrical hole via the gas in the radial bearing clearance, and the radial sleeve bearing surface provided on the fixed shaft faces at least one of the radial bearing surface and the radial bearing surface. This is because a herringbone-shaped groove is provided.

[Function 1] When the rotating member 47 rotates, the pressure of the lubricant in the thrust bearing clearance 55 increases due to the pumping action of the groove 45 for generating dynamic pressure, and the rotating member 47 rotates without contacting the housing 31. Also, herringbone groove 63
Due to the pumping action, the pressure of the gas within the radial bearing clearance 66 increases, and the rotating member 47 rotates without contacting the fixed shaft 59.

[Embodiment 1] An embodiment of the present invention will be described based on the drawings. In FIG. 1, a housing 31 includes a flat holder 33 and a holder 3.
A disk-shaped thrust bearing member 35 that fits into the cylindrical hole provided in 3) with a clearance, a flat plate-shaped mounting member 37 attached to the outer periphery of the holder 33, and a cylindrical thrust bearing member 35 attached to the outer periphery of the mounting member 3). It is composed of a case 39 and a flat fixed shaft support member 41 attached to the upper part of the case 39.

The inside of the housing 31 is sealed by the housing 31 to prevent foreign matter from entering into the housing 31 from outside the housing 31. The lower surface of the thrust bearing member 35 is planar, and the thrust bearing member 3
The lower surface of 5 is in contact with a convex spherical surface provided on the bottom surface of the cylindrical hole of the holder 33.6 The outer peripheral surface of the thrust bearing member 35 is elastically connected to the inner peripheral surface of the cylindrical hole of the holder 33 via an O ring. The thrust bearing member 35 is supported by the holder 33.
It is possible to align with. An air vent hole 4 that opens to the outer surface of the holder 33 is provided at the bottom of the cylindrical hole of the holder 33.
2 is provided, and the thrust bearing member 35 is attached to the holder 3.
It can be easily installed in the cylindrical hole of No. 3. The upper surface of the thrust bearing member 35 is provided with a planar thrust bearing surface 43, and this thrust bearing surface 43 is provided with a spiral groove 45 for generating dynamic pressure as shown in FIG. .

A rotating member 47 is disposed on the thrust bearing surface 43,
This rotating member 47 includes a sleeve 49 and a closing member 51 fitted and attached to the lower end of the cylindrical hole of the sleeve 49.
.

It is growing. The rotating member 47 has a planar thrust bearing surface 53 that faces the thrust bearing surface 43, and the maximum diameter of the thrust bearing formed by the thrust bearing surface 53 and the thrust bearing surface 43 is equal to the radial bearing described later. The diameter is smaller than the diameter of the surface 61. A liquid or semi-liquid lubricant such as oil or grease is present in the thrust bearing clearance 55 between the thrust bearing surface 43 and the thrust bearing surface 53. The rotating member 47 has a cylindrical hole 57 on the surface opposite to the thrust receiving surface 53, and a fixed shaft 59 is fitted into the cylindrical hole 57. An air communication hole 60 opening to the outer surface of the rotating member 4 is provided at the bottom of the cylindrical hole 57, so that the fixed IIjJ59 can be easily fitted into the PlfII-shaped hole 57.

The upper part of the fixed shaft 11159 is attached to the fixed shaft support member 41, and the fixed shaft 59 has cylindrical radial bearing surfaces 61 at two locations in the axial direction. The two radial bearing surfaces 61 are each provided with a herringbone-shaped groove 63, and the two radial bearing surfaces 61 are provided with cylindrical radial bearings provided at two locations in the axial direction of the cylindrical hole 57. The surfaces 65 and radial bearing gaps 66 face each other with gas such as air interposed therebetween.

A photometering body 67 is attached as a load member to the upper half of the outer peripheral surface of the rotating member 47, and this photometering body 67 has approximately the same height as the lath window 69 for passing laser light attached to the case 39. It is located in the A rotor 71 is attached to the lower half of the outer peripheral surface of the rotating member 47.
is opposed to the stator 73 attached to the attachment member 37 in a plane.

Note that the grooves 45 for generating dynamic pressure may not be spiral grooves but may be other grooves such as a herringbone groove. Furthermore, the groove 45 for generating dynamic pressure may be provided on at least one of the thrust bearing surface 43 and the thrust bearing surface 53.

Further, a herringbone-shaped groove 63 may be provided in at least one of the radial bearing surface 61 and the radial bearing surface 65.

Furthermore, the inside of the housing 31 is connected to outside air.
(2) It may be indirectly sealed by the housing 31 via a gas filter that communicates with the gas inside the container.

may be used upside down.

Furthermore, the rotating member 47 is attached to the holder 33 or the mounting member 37.
It is also possible to install a sealing member that faces the sealing member with a sealing gap therebetween. In this way, the lubricant in the thrust bearing clearance 55 is not scattered from the thrust bearing clearance 55, and the lubrication performance between the thrust bearing surface 43 and the thrust bearing surface 53 is good, and the optical photometering body 67 and the like are lubricated. Will not be contaminated by splashing.

[Effect of the Invention J According to this invention, since the lubricant is present in the thrust bearing clearance 55, it has a large thrust load capacity, and the radial bearing composed of the radial bearing surface 61 and the radial bearing surface 65 has only a radial load capacity. Therefore, the axial dimension of the fixed shaft 59 can be shortened.

Therefore, the axial dimension of the hydrodynamic fluid receiving device can be shortened, and the whole can be made compact.

Furthermore, since the lubricant is present in the thrust bearing clearance 55, there is little wear between the thrust bearing surfaces 43 and 53, improving the durability of the hydrodynamic bearing device and reducing friction torque.

Furthermore, since the radial bearing surface 61 faces the two-noal bearing surface 65 via the gas in the radial bearing clearance 66, even if the radial bearing surface 65 is at a high circumferential speed, the radial bearing height 6
6, such as the photometering mirror 67 as a load member, are dirty (and have low friction torque).

Furthermore, since it has a large thrust load capacity, it is also possible to use a plane-opposed motor that has a large axial suction force.

In addition, since the thrust load capacity is large, the thrust bearing surface 4
3 and the thrust bearing surface 53 can be made smaller than the diameter of the radial bearing surface 61.

In this way, even at high speed rotation, the circumferential speed of the outer peripheral end of the thrust receiving surface 53 is small, so there is less lubricant scattering from the thrust bearing clearance 55, and the optical photometering body 67 etc. are not contaminated.

Also, the friction torque is low.

Furthermore, when the housing 31 directly or indirectly seals the gas inside the housing 31, external foreign matter does not enter into the housing 31, which improves the life of the hydrodynamic fluid receiving device and also prevents the optical photometer body 67 from becoming dirty. There is no.

Further, the housing 31 is in contact with the holder 33 and the thrust bearing member 35 has a thrust bearing surface 43.
If the thrust bearing member 35 can be aligned with the holder 33, a slight machining error between the thrust bearing surface 43 and the thrust bearing surface 53 can be tolerated.

Furthermore, when the fixed shaft 59 has the radial bearing surfaces 61 at two locations in the axial direction, there is an effect that the vibration of the rotating member 47 is reduced.

Brief explanation of the q-plane - Ship Figure 1 is a sectional view of a hydrodynamic bearing device showing an embodiment of the present invention, Figure 2 is a plan view of the thrust bearing surface shown in Figure PI & 1, and Figure 3 is a conventional 1 is a sectional view of a hydrodynamic bearing device of FIG.

In the figure, 31 is a housing, 43 is a thrust bearing surface, and 45
is a groove for generating dynamic pressure, 47 is a rotating member, 53 is a thrust bearing surface, 55 is a thrust bearing clearance, 57 is a cylindrical hole,
59 is a fixed shaft, 61 is a radial bearing surface, 63 is a herringbone groove, 65 is a radial bearing surface, and 66 is a radial bearing clearance.

Patent applicant: NSK Ltd. Figure 1 chest and I

Claims (1)

[Claims] 1. The planar thrust bearing surface provided on the housing faces the thrust bearing surface provided on the rotating member via a lubricant in the thrust bearing clearance, and the thrust bearing surface and the thrust bearing surface a groove for generating dynamic pressure is provided in at least one of the rotary members, the rotary member has a cylindrical hole on the surface opposite to the thrust receiving surface, and a fixed shaft fitted in the cylindrical hole is attached to the housing; The cylindrical radial bearing surface provided on the fixed shaft faces the radial bearing surface provided in the cylindrical hole via the gas in the radial bearing clearance, and a herring is formed on at least one of the radial bearing surface and the radial bearing surface. A hydrodynamic bearing device with bone-shaped grooves. 2. The hydrodynamic bearing device according to claim 1, wherein the maximum diameter of the thrust bearing constituted by the thrust bearing surface and the thrust bearing surface is smaller than the diameter of the radial bearing surface. 3. The hydrodynamic bearing device according to claim 1, wherein the housing directly or indirectly seals the gas within the housing. 4. The hydrodynamic bearing according to claim 1, wherein the housing includes a holder and a thrust bearing member that is in contact with the holder and has a thrust bearing surface, and the thrust bearing member is alignable with respect to the holder. Device. 5. The hydrodynamic bearing device according to claim 1, wherein the fixed shaft has radial bearing surfaces at two locations in the axial direction.