JPH08210346A - Bearing device - Google Patents

Abstract

PURPOSE: To provide a bearing device with increased load capacity at low speed rotation. CONSTITUTION: A rotary member 20 is supported in the radial direction through a dynamic pressure type radial bearing by grooves 11, 12 for generating the dynamic pressure provided on the outer diameter surface of a fixed shaft 10 fixed to a housing 40, and supported in the axial direction through a dynamic pressure type thrust bearing by a groove 23 for generating the dynamic pressure provided on the end face opposite to the fixed shaft of the thrust bearing 22. The respective dynamic pressure type bearings are lubricated with the lubricant such as grease, and the lubricant flown out of the dynamic pressure type bearing is absorbed by the porous member 33 arranged between the rotary member 20 and the housing 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device used in information equipment, audio equipment, video equipment and the like.

[0002]

2. Description of the Related Art Conventionally, for example, a scanner unit for deflecting a laser beam shown in FIG. 2 is known as a device in which a bearing device of this type is incorporated. This bearing device has a fixed shaft 1
The flange 1a attached to the lower end of the is fixed to the housing 9 in an airtight manner, and the sleeve 3 as a rotating member is rotatably fitted around the fixed shaft 1. A plurality of spiral dynamic pressure generating grooves 2 are provided on the outer diameter surface of the fixed shaft 1, and a dynamic pressure radial bearing is formed between the fixed shaft 1 and the sleeve 3. A thrust receiver 4 having an air vent hole 4a is fixed to the upper end portion of the sleeve 3, and the thrust receiver 4 faces the upper end surface of the fixed shaft 1 formed in a convex spherical shape.

A flange 5 is integrally formed on the outer peripheral surface of the sleeve 3 substantially in the center in the axial direction, and a polygon mirror 6 is fitted on the outer diameter surface of the sleeve on the axially upper side with the flange 5 interposed therebetween. The rotor magnet 7a of the drive motor is fitted into the axially lower side surface of the flange 5 so as to be in close contact with the axially lower side surface thereof, and the axially lower side surface of the flange 5 is closely fitted to the rotor magnet 7a. The polygon mirror 6, the rotor magnet 7a, and the sleeve 3 are rotated as an integrated rotating body.

On the upper end surface of the polygon mirror 6 and the lower end surface of the rotor magnet 7a, balance rings 8a, respectively, for correcting the radial weight of the rotating body,
8b is attached. On the side wall of the housing 9, a glass window 9a for transmitting laser light is provided at a position facing the polygon mirror 6, and on the inner surface of the side wall of the housing 9, a stator coil 7b of a drive motor which faces the rotor magnet 7a in a cylindrical surface. Is attached.

Clean air is enclosed in the housing 9 of the above-mentioned bearing device, and a dynamic pressure type radial bearing between the fixed shaft 1 and the sleeve 3 and a thrust bearing between the fixed shaft 1 and the thrust receiver 4 are provided. , And operates as an air bearing using this clean air as a lubricant. In the above bearing device, the sleeve 3, the polygon mirror 6 and the rotor magnet 7a are driven by the rotational force generated in the rotor magnet 7a by energizing the stator coil 7b of the drive motor.
When they rotate as a unit, the dynamic pressure generating groove 2 of the fixed shaft 1
A dynamic pressure is generated by the air bearing to generate an air film in the radial bearing clearance, and the pressure of this air film supports the sleeve 3 in the radial direction while keeping the sleeve 3 in a non-contact state with the fixed shaft 1. The thrust receiver 4 flows into the thrust bearing clearance from the radial bearing clearance, and the air vent hole 4
It is axially supported by the air exhausted from a.

[0006]

In the conventional bearing device, since the dynamic pressure type radial bearing between the fixed shaft 1 and the sleeve 3 is an air bearing, there is no problem in load capacity at high speed rotation. Since air has a low viscosity, when it is used at low speeds, for example, several thousand revolutions or less, the load capacity becomes insufficient, and there is a problem that the radial bearing surfaces and the thrust bearing surfaces come into contact with each other and the bearing surfaces are damaged during rotation. .

An object of the present invention is to solve the above problems and provide a bearing device having a large load capacity during low speed rotation.

[0008]

The bearing device of the present invention comprises:
The rotating member is supported by the housing via a dynamic pressure type bearing,
The dynamic pressure type bearing is lubricated with a lubricant such as oil or grease, and the porous member arranged between the rotating member and the housing absorbs the lubricant flowing out.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a first embodiment of the present invention will be described.
An example will be described with reference to FIG. In the figure, the bearing device of the present invention is applied to the laser beam deflecting scanner unit described in FIG. A flange 21 having a balance correction groove 21a is integrally formed on the upper end of a sleeve 20 as a rotating member that is fitted into the fixed shaft 10.
A polygon mirror 24 as an additional rotating member is fitted and inserted into the sleeve outer diameter surface on the axially lower side of the flange 21 to form the flange 2.
The polygon mirror 24 is attached to the side surface of the No. 1 axially lower side.
An annular rotor magnet 26 of the drive motor is arranged radially outward of the sleeve outer diameter surface via the yoke 25 on the axially lower end surface of the sleeve 25. The cover member 28 fitted to the surface is brought into close contact with the polygon mirror 24 and the rotor magnet 2.
The yoke 25 having 6 and the cover member 28 and the like are gathered on the lower side of the flange 21 in the axial direction and integrally fixed to the sleeve 20 by bolts 29. Therefore, the rotor magnet 26 is attached to the sleeve 20.

The lower end of the fixed shaft 10 is a housing 40.
The sleeve 20 and the fixed shaft 10 constitute a dynamic pressure type radial bearing by means of herringbone-shaped dynamic pressure generating grooves 11 and 12 provided on the outer diameter surface of the fixed shaft 10. A cylindrical thrust receiver 22 is fixed to the upper end of the inner diameter surface of the sleeve 20, and a dynamic pressure generating groove 23 is provided on the end surface of the thrust receiver 22 facing the fixed shaft 10. The end surface and the upper end surface of the fixed shaft 10 constitute a dynamic pressure type thrust bearing. Further, an axial upper portion of the thrust receiver 22 is projected from the upper end surface of the sleeve 20 to form a cylindrical support portion 51. Therefore,
Both the thrust receiver support 51 and the support 52 provided on the outer peripheral surface of the lower end of the sleeve are horizontally supported, and the sleeve 20, the polygon mirror 24, and the rotor magnet 2 are supported.
6, the weight imbalance in the radial direction of the rotating body including the cover member 28 and the like is detected, and the sleeve balance correction groove 21 is detected.
By using a and the balance correction groove provided on the lower surface of the outer peripheral portion of the cover member 28, the weight imbalance between the upper and lower portions of the rotating body is removed.

The dynamic pressure type radial bearing and the dynamic pressure type thrust bearing are lubricated by a lubricant such as oil or grease filled in the radial bearing clearance and the thrust bearing clearance. Above the inner diameter surface of the sleeve 20, an air vent groove 30 is provided in the axial direction from the space between the lower end surface (thrust bearing surface) of the thrust receiver 22 and the upper end surface (thrust receiving surface) of the fixed shaft 10. An air vent hole 31 is provided in the radial direction from the space between the inner diameter surfaces (radial bearing surfaces) of the sleeve 20 opposed to the dynamic pressure generating grooves 11 and 12 of the fixed shaft 10. The opening of the air vent hole 31 to the outer diameter surface of the sleeve communicates with the air vent groove 32 axially provided on the outer diameter surface of the sleeve 20 and the small diameter portion provided at the lower end of the outer diameter surface of the sleeve 20. . When the lubricant of the radial bearing and the thrust bearing and the air bubbles contained therein flow out from the air vent hole 31, the air vent groove 32 is provided along the inner peripheral surface of the cover member 28.
Also, the small diameter portion is allowed to flow down and be discharged to the concave portion at the central portion in the radial direction of the housing 40, so that the splash of the lubricant is not scattered in the housing cover 41.

The lubricant discharged from the dynamic pressure type bearing to the concave portion of the housing 40 is absorbed by the porous member 33 such as felt arranged in the concave portion of the housing 40 in the radial direction. A window hole 42 is provided in a side wall of the housing cover 41 at a position facing the polygon mirror 24, and a rotor magnet 2 is provided on an inner surface of a bottom wall of the housing 40.
An annular stator coil 27 that faces 6 is attached to form a planar drive motor.

In addition, on the top wall of the housing cover 41,
A set screw 43 is screwed as a sleeve pressing member during transportation. In the bearing device having the above structure, when the sleeve 20, the polygon mirror 24, the rotor magnet 26, the cover member 28, and the like are integrally rotated by the drive of the drive motor, the dynamic pressure generating grooves 11 and 12 of the fixed shaft 10 are formed. An oil film is generated in the radial bearing clearance by the dynamic pressure, and the pressure of the oil film supports the sleeve 20 in the radial direction while keeping the sleeve 20 in a non-contact state with the fixed shaft 10, and the dynamic pressure generating groove of the thrust receiver 22. An oil film is generated in the thrust bearing clearance by the dynamic pressure of 23, and the pressure of this oil film axially supports the thrust receiver 22 in a non-contact state with the fixed shaft 10. Therefore, the sleeve 20 is supported by the housing 40 via the dynamic pressure type bearing.

The dynamic pressure generating groove of the dynamic pressure type radial bearing may be provided on the inner diameter surface of the sleeve, or may be provided on both the outer diameter surface of the fixed shaft and the inner diameter surface of the sleeve. Further, the dynamic pressure generating groove 23 of the dynamic pressure type thrust bearing may be provided on the upper end surface of the fixed shaft 10 or on both end surfaces of the fixed shaft 10 and the thrust receiver 22. Further, the housing cover in this embodiment does not need to be hermetically sealed since it only functions as a dust shield because the bearing is oil-lubricated. Therefore, the housing cover can be omitted.

In the above embodiments, the case where the present invention is applied to the laser light deflection scanner unit has been described, but the present invention can also be applied to information equipment, audio equipment, video equipment and the like.

[0016]

Since the dynamic pressure type bearing that supports the rotating member is lubricated with a lubricant such as oil or grease, a large load capacity can be obtained even when used at low speed rotation, and the shaft diameter is small and the height is small. Since the height can be lowered, the bearing device can be downsized. Further, when the lubricant of the dynamic pressure type bearing flows out, it is absorbed by the porous member and scattering is prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an example in which the present invention is applied to a laser light deflection scanner unit.

FIG. 2 is a vertical cross-sectional side view showing a conventional laser light deflection scanner unit.

[Explanation of symbols]

 10 Fixed shaft 11, 12 Dynamic pressure generating groove 20 Sleeve 22 Thrust receiving 23 Dynamic pressure generating groove 24 Polygon mirror 26 Rotor magnet 33 Porous member 40 Housing

Claims (1)

[Claims] 1. A rotary member is supported by a housing through a dynamic pressure type bearing, and the dynamic pressure type bearing is lubricated by a lubricant such as oil or grease, and is provided between the rotary member and the housing. The bearing device, wherein the quality member absorbs the outflowing lubricant.