JP2993852B2 - Bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device.

[0002]

2. Description of the Related Art Conventionally, for example, in high-speed LBP (laser beam printer) scanner bearing devices, ball bearings have been used as bearings. The study of bearings is underway.

FIG. 2 shows a high-speed LBP scanner motor to which a bearing device having this sintered oil-impregnated bearing is applied, and in order to avoid complication, only the right half from the center line is shown. .

In FIG. 1, reference numeral 1 denotes a rotating shaft, and the rotating shaft 1 is provided with a lubricating fluid (oil, oil, etc.) by a sintered oil-impregnated bearing 4, 4 in a bearing holder 3 erected on a substrate 2. (A fluid) so as to be rotatable in the radial direction. A boss 7 on which a polygon mirror 10 is mounted is fixed to an upper end (open side) of the rotating shaft 1 in the drawing, and the boss 7 has a substantially cup-shaped rotor case 5 that rotates integrally with the rotating shaft 1. Is fixed. An annular rotor magnet 6 is fixed to the inner peripheral surface of the flange portion 5a of the rotor case 5, and N and S poles of driving magnetic poles are alternately magnetized on the rotor magnet 6. A stator core 8 is disposed at an inner circumferential position facing the rotor magnet 6.
Is wound with a driving coil (not shown).

A thrust plate 9 is fixed to the lower end (closed side) of the bearing holder 3 in the figure.
The rotating shaft 1 is placed on the upper side via a lubricating fluid such as oil.

The rotor magnet 6 and the stator core 8
Are shifted in the axial direction, so that the rotating body (the rotating shaft 1, the boss 7, the rotor case 5, the rotor magnet 6, and the polygon mirror 10) has a magnetic force toward the thrust plate 9 side (closed side). A suction force is applied. That is, the rotating body is held in the axial direction by the magnetic attraction force.

When a predetermined drive voltage is applied to the coil, the polygon mirror 10 rotates together with the rotation axis 1 and the like, and the laser light converged on the polygon mirror 10 due to the rotation of the polygon mirror 10 is not shown. The image can be scanned on the image recording medium.

[0008]

However, the above-mentioned bearing device has the following problems. That is, in a high-speed motor as described above (for example, a motor of 12000 rpm or more), a lubricating fluid such as oil (interposed between the sintered oil-impregnated bearing 4 and the rotating shaft 1) is scattered by centrifugal force, It flows out along a passage (a space formed between the boss 7 as a rotating member and the bearing holder 3 as a fixing member) forming an open portion, that is, as shown by an arrow in FIG. Since it flows out from the bearing part,
There has been a problem that the lubricating fluid is insufficient in the bearing portion, the bearing rigidity is reduced, the run-out of the rotating shaft 1 is increased, and the bearing is eventually seized.

Accordingly, the present invention provides a bearing device in which lubricating fluid scattered by centrifugal force is returned to a sintered oil-impregnated bearing, seizure of the bearing is prevented without reducing bearing rigidity, and reliability is improved. With the goal.

[0010]

According to a first aspect of the present invention, there is provided a bearing device in which a fixed member having a closed end at one end and an open end at the other end is fixed in the concave portion of the fixed member. A sintered oil-impregnated bearing, a rotating shaft inserted into the sintered oil-impregnated bearing and rotatably supported by the sintered oil-impregnated bearing via a lubricating fluid, and opened from the sintered oil-impregnated bearing in the axial direction of the rotating shaft. A rotating member fixed to a side of the bearing member, wherein the rotating member is provided with an annular protrusion that projects axially toward the sintered oil-impregnated bearing to form a first wall, and the fixed member Wherein the holder of the sintered oil-impregnated bearing is axially projected from the end face of the first wall toward the open side to form a second wall.

[0011] In order to achieve the above object, the bearing device of the second means has an inner peripheral surface of the first wall in addition to the first means.
It is characterized by having a tapered surface expanding toward the closing side.

[0012]

According to the bearing device of the first means, a part of the lubricating fluid scattered by the centrifugal force is returned to the sintered oil-impregnated bearing by the first wall. Further, the remaining lubricating fluid scatters further outward than the first wall, but since the second wall projects axially from the end face of the first wall toward the open side, the second wall is As a result, the remaining lubricating fluid is also returned to the sintered oil-impregnated bearing.

[0013] According to the bearing device of the second means, the lubricating fluid scattered on the inner peripheral surface of the first wall is favorably transmitted along the tapered surface expanding toward the closing side, and the sintering oil-impregnated bearing and the lubricating fluid are not satisfactorily formed. You are heading to the second wall.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a motor to which a bearing device according to an embodiment of the present invention is applied, wherein the same components as those described in the related art are denoted by the same reference numerals, In order to avoid this, the description here is omitted.

In the bearing device of this embodiment, a boss 7 as a rotating member fixed to the open side of the sintered oil-impregnated bearing 4 in the axial direction of the rotary shaft 1 An annular protruding portion (first wall) 7a protruding in the direction is provided. The bearing holder 3 for holding the sintered oil-impregnated bearing 4 projects axially from the end face 7c of the first wall 7a toward the open side (upward in the figure), and the second wall 3a.
Is formed. In other words, the boss 7 has an annular projection (first wall) 7a that projects axially toward the sintered oil-impregnated bearing 4 from the open end of the second wall 3a.
Is provided.

Accordingly, the lubricating fluid scattered by the centrifugal force travels on the inner peripheral surface 7b by the first wall 7a, and a part of the lubricating fluid is returned to the sintered oil-impregnated bearing 4 as shown by the arrow A in the drawing. Become. Further, the remaining lubricating fluid that has traveled along the first wall 7a and scattered outward due to centrifugal force is also removed from the second wall 3a.
a protrudes in the axial direction from the end face 7c of the first wall 7a toward the open side, as shown by the arrow B in the figure, the inner peripheral surface of the second wall 3a Will be returned.

Here, since the sintered oil-impregnated bearing 4 is formed with a number of known porous bodies, the first and second walls 7a, 3 are formed.
The lubricating fluid returned by a is returned to the sliding surface by the sintered oil-impregnated bearing 4. That is, all the lubricating fluid scattered by the centrifugal force is returned to the sintered oil-impregnated bearing 4, so that the reduction of the bearing rigidity and the seizure of the bearing are prevented, and the reliability can be improved.

In this embodiment, as shown in FIG.
Since the inner peripheral surface 7b of the first wall 7a is formed as a tapered surface that spreads toward the closed side, the lubricating fluid scattered on the inner peripheral surface 7b of the first wall 7a changes the tapered surface that spreads toward the closed side. Accordingly, the lubricating fluid is guided to the sintered oil-impregnated bearing 4 and the second wall 3a satisfactorily, so that the above-described operation of returning the lubricating fluid to the sintered oil-impregnated bearing 4 can be more effectively performed. ing.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say, for example, at least one of the sintered oil-impregnated bearing 4 and the portion of the rotary shaft 1 facing the sintered oil-impregnated bearing 4 in the above embodiment,
For example, a bearing device in which a dynamic pressure generating groove having a herringbone shape or the like is provided and a lubricating fluid is interposed in a sliding portion to generate a dynamic pressure may be used. Also, a magnetic fluid can be used as the lubricating fluid.

Further, in the above-described embodiment, an example in which the bearing device is applied to a high-speed LBP scanner motor is described. However, the present invention is not limited to this, and can be similarly applied to other motors. It is.

[0021]

As described above, according to the bearing device of the first aspect of the present invention, the rotating member is provided with an annular projecting portion projecting in the axial direction toward the sintered oil-impregnated bearing to form the first wall and fix it. Since the holder portion of the sintered oil-impregnated bearing in the member protrudes in the axial direction from the end face of the first wall toward the open side to form the second wall, the lubricating fluid scattered by the centrifugal force is not applied to the first wall. A part of the lubricating fluid is returned to the sintered oil-impregnated bearing, and the remaining lubricating fluid scattered further outward than the first wall also has the second wall in the axial direction toward the open side from the end face of the first wall. , And is returned to the sintered oil-impregnated bearing by the second wall. That is, all the lubricating fluid scattered by the centrifugal force is returned to the sintered oil-impregnated bearing, thereby preventing a reduction in bearing rigidity and seizure of the bearing, and improving reliability.

According to the bearing device of the second invention, the first
The inner peripheral surface of the wall is a tapered surface that spreads toward the closed side, so that the lubricating fluid scattered on the inner peripheral surface of the first wall sinters well along the tapered surface that spreads toward the closed side. It is directed toward the oil-impregnated bearing and the second wall, and the effect of the first invention can be further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a motor to which a bearing device according to an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view of a motor to which a bearing device according to the related art is applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotating shaft 3, 9 fixing member 3a second wall 4 sintered oil-impregnated bearing 7 rotating member 7a first wall 7b inner peripheral surface of first wall 7c end surface of first wall

Claims (2)

(57) [Claims] 1. A fixed member having a concave portion having one end closed and another open, a sintered oil-impregnated bearing fixed in the concave portion of the fixed member, and a lubricating fluid inserted into the sintered oil-impregnated bearing. A rotating shaft rotatably supported by the sintered oil-impregnated bearing, and a rotating member fixed to the open side of the sintered oil-impregnated bearing in the axial direction of the rotating shaft. An annular protrusion protruding in the axial direction toward the sintered oil-impregnated bearing is provided as a first wall, and a holder part of the sintered oil-impregnated bearing in the fixing member is disposed at an end surface of the first wall. A bearing device, wherein the second wall is formed by projecting in an axial direction toward an open side. 2. The bearing device according to claim 1, wherein an inner peripheral surface of the first wall is a tapered surface expanding toward a closing side.