KR19980078091A - Fluid Bearing Device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid bearing device, comprising: a shaft inserted into a shaft mounting hole of a motor housing, a shaft inserted into a shaft mounting hole of a motor housing, and a predetermined end surface and a predetermined end surface of the shaft. It maintains a gap and opposes, and the finish opening for closing the shaft installation hole is inserted into the shaft, and the shaft and the predetermined interval between the shaft and the finish is mounted on the finish opening to face the rotation of the motor rotor Provides a fluid bearing device comprising a bearing member for supporting a multi-point surface, to effectively reduce the time and cost of work occurred during the machining of the bearing groove to increase the work efficiency, and to support a number of places on the bottom of the shaft The shaft is rotated more stably, and at the same time, the invention prevents whirling, which is a characteristic of fluid bearings.

Description

Fluid Bearing Device

The present invention relates to a fluid bearing device, and more particularly, to a motor mounted on a laser printer, a laser scanner, a camcorder, a video tape recorder, and the like, by improving the structure of the fluid bearing device applied to the motor without the bearing groove. The present invention relates to a fluid bearing device that makes the rotation of the motor shaft more uniform and stable.

Recently, the head drive device of video tape recorder or the scanning motor or camcorder drive motor, which is the polygon mirror drive device of laser printer, is gradually increasing in size and compactness, and these drive devices are precise, stable and can rotate at high speed. In order to achieve the above-mentioned bearing, a fluid bearing device is mainly used in which a shaft and a member supporting the shaft are rotated while rotating using air pressure. Such a fluid bearing device has a radial load and exposed force. Bearing grooves of various shapes, such as spiral bearing grooves and herringbone bearing grooves, have been developed in the shaft or the member supporting the shaft to minimize the frictional force that hinders the rotation of the shaft by the test load.

A conventional fluid bearing device having the above purpose will be described in detail with reference to the accompanying drawings as follows.

Here, a scanning motor will be described as an embodiment.

1 is a schematic configuration diagram of a scanning motor to which a conventional fluid bearing device is applied, and FIG. 2 is a cross-sectional view taken along the line A-A in FIG.

The motor 1 is provided with a stator 11 and a rotor 20 in the housing 10, and the shaft 21 of the rotor 20, in which the rotor represents a rotating body of the polygon mirror, has a housing 21. 10 is inserted into the shaft installation hole 12, the shaft installation hole 12 is the lower end is finished with the finish opening 30, the bearing member 31 to the finish opening 30 is the shaft 21 It has a basic configuration mounted to face the bottom of the.

In the conventional fluid bearing device, a plurality of bearing grooves 21a having a herringbone shape are formed on the outer surface of the shaft 21, and a spiral bearing groove 31a is formed on the upper surface of the bearing member 31. .

The finish 30 is fastened with a bolt 32 when combined with the housing 10.

The herringbone-shaped bearing groove (21a) is the air is collected in a portion where the groove (21a) is bent, the air is supported between the shaft 21 and the shaft installation hole 12, the spiral bearing groove ( 31a) collects air between the shaft 21 and the bearing member 31 toward the center side as shown in FIG. 2 so that air pressure is generated, and the collected air supports the bottom surface of the shaft 21 only as one point. do.

As described above, only one point is supported by a narrow pressure point for supporting the shaft. When the pressure point is narrow as described above, even if a slight shake is applied to the motor, the shaft is rotated out of position, and the product is expected to operate correctly. Becomes difficult.

In addition, the bearing groove formed on the outer surface of the shaft is formed to prevent the whirling phenomenon, which is a characteristic problem of the fluid bearing device in addition to the action of collecting the air pressure at a predetermined position as follows.

In general, the rotating shaft rotates and rotates, which means that the axis itself rotates, and the rotation rotates around the center of the axis in which the axis rotates. It is a characteristic of the fluid bearing device to use the bearing action.

When a general shaft without bearing groove is inserted into the shaft installation groove and rotated, a predetermined fluid pressure action occurs on the outer surface of the shaft and the inner surface of the shaft installation hole. However, in such a rotating state, the fluid is formed on the outer surface of the shaft and the inner surface of the shaft installation hole. Since the axis of pressure concentration is not constant, the axis rotates unevenly before, after, left, and right, and is greatly transferred from the usual revolution trajectory, and the rotational efficiency of the axis is drastically lowered due to the above-described idle action. It is called whirling phenomenon.

When the whirling phenomenon occurs, not only the journal portion of the shaft is unevenly operated when the shaft rotates, but also the thrust action generated from the bottom surface becomes very nonuniform, and the thrust phenomenon is a non-uniform factor. When it occurs, the shaft deviates much from the usual revolution trajectory, and the pneumatic pressure supporting the bottom of the shaft as a point is exerted on the pressure as many as the shaft is displaced, not the center of the shaft bottom.

The bearing groove for preventing the unstable state of the shaft due to the whirling phenomenon is formed on the upper surface of the member or the bottom of the shaft by etching or electric discharge, etc. The process takes not only a long time but also a groove of a few μm. The following is very difficult to lower the work efficiency, the expensive processing equipment is required for the above operation is a costly problem occurs.

The present invention has been made in order to solve the above problems and to obtain a more positive effect, by processing a predetermined shape on the bearing member without forming a bearing groove on the bottom of the shaft or the upper surface of the bearing member, so that the bottom of the shaft is supported by multiple points, The purpose is to be able to rotate stably.

In order to achieve the above object effectively, the present invention has the following features.

The present invention provides a fluid bearing apparatus capable of generating a thrust pressure at an end surface of a shaft in a motor.

A shaft inserted into the shaft installation hole of the motor housing;

A closing tool for maintaining a predetermined distance from the end surface of the shaft so as to face each other and closing the shaft installation hole in which the shaft is inserted;

It is characterized in that it comprises a bearing member for maintaining a predetermined interval between the shaft and the finish sphere and is mounted to the finish sphere to support the opposite surface during the rotation of the motor rotor.

The bearing member is characterized in that it comprises a fluid pressure generating projection for generating a plurality of air pressure by rotating the shaft is formed protruding along the periphery outside the outer surface facing the shaft.

The fluid pressure generating protrusion is characterized by having an inclined surface close to the shaft in the rotational direction of the shaft.

1 is a schematic cross-sectional view of a scanning motor to which a conventional fluid bearing device is applied.

2 is a plan view showing only the bearing member in Figure 1;

Figure 3 is a schematic cross-sectional view of the scanning motor to which the present invention fluid bearing device is applied.

Figure 4 is a perspective view showing only the bearing member in Figure 3;

5 is a conceptual diagram showing a fluid pressure generation state applied to the bottom of the shaft.

6 is a schematic cross-sectional view showing another embodiment of the present invention.

Explanation of Signs of Major Parts of Drawings

1: motor 10: housing

30: finish 40: bearing member

An embodiment of the present invention having the above features will be described in detail with reference to the accompanying drawings.

Here, the embodiment will describe a scanning motor, and in detail, it is assumed that the shaft is installed and rotated in the shaft installation groove.

3 is a schematic cross-sectional view of a scanning motor to which the present invention is applied, and FIG. 4 is a perspective view showing only a bearing member in FIG. 3.

In the motor 1, the shaft 21 of the rotor 20 is inserted into the shaft mounting hole 12 of the housing 10 so that the rotor 20 is mounted at the predetermined position of the housing 10. It is installed to be rotatable from the upper side of the, and the finish hole 30 is mounted on the bottom surface of the shaft installation hole 12, and the predetermined intervals between the shaft 21 and the shaft 21 and the shaft 21 It has a basic configuration in which the bearing member 40 is mounted to the finish opening (30).

A plurality of bearing grooves 21a are formed on the outer surface of the shaft 21 so as to have a bearing action in the shaft installation hole 12.

The finish 30 is fastened by the bolt 32 when combined with the housing 10.

Here, the fluid bearing device has a shaft 21, a finisher 30 for closing the bottom surface of the shaft installation hole 12, the shaft 21 is installed, and the finisher 30 and the shaft 21 It is configured to include a bearing member 40 provided in.

The bearing member 40 has a cylindrical shape, and a plurality of protrusions are formed along the periphery of the surface opposite to the shaft 21, that is, the upper surface, to generate air pressure by the shaft 21 being rotated. 41 is formed.

The fluid pressure generating protrusion 41 is continuously formed on the upper surface of the bearing member 40, and the shape has a front shape having a generally written wedge shape, and is close to the shaft 21 according to the rotational direction of the shaft 21. Has an inclined surface 42.

The bearing member 40 is preferably formed in a circular plane.

Naturally, the inclined surface 42 of the shaft 21 and the fluid pressure generating protrusion 41 should have an extremely fine surface roughness.

Hereinafter, the operation of the embodiment of the present invention having the configuration as described above in detail.

Due to the external electrical signal, the rotor 20 is rotated about the shaft 21, and a well-known fluid bearing action occurs between the shaft 21 and the shaft mounting hole 12 due to the bearing groove 21a. .

At this time, the air between the shaft 21 and the bearing member 40 is rotated at the same time according to the rotation direction of the shaft 21, the rotated air and the fluid pressure generating protrusion 41 of the bearing member 40 and Interfering between the bottom of the shaft 21, the shaft 21 is rotated without contacting the bearing member 40 surface.

At this time, the meaning of interference means that the shaft 21 floats in the fluid pressure generating protrusion 41 due to the air existing between the shaft 21 and the bearing member 40 when the shaft 21 rotates. The resulting action is as follows.

As the shaft 21 is rotated, the air that is rotated has a maximum pressure when it passes through an upward end of the inclined surface 42 of the fluid generating protrusion 41, which is due to the space through which the air must pass. As shown in FIG. 5, when the space of each portion of the inclined surface 42 is different from the bottom of the shaft 21, the pressure when passing through the space-in general, when the fluid passes a narrow space, the pressure increases, and conversely, a large space passes. At this time the pressure is relatively low, which is based on well-known facts. As a result, the maximum pressure is generated at the upstream end where the space between the shaft 21 is narrow and the space through which the air passes is narrow.

The air at the maximum pressure supports the shaft, and the maximum pressure point of the air providing the flotation force is generated by the number of the fluid pressure generating protrusions 41 to support a plurality of places on the bottom surface of the shaft 21 to stably support the shaft. do.

Although the present invention has described an embodiment in which the shaft is rotated, it is also possible to implement a motor having a rotor in which the shaft is fixed and rotated separately from the shaft.

Another embodiment of the present invention

6 is a cross-sectional view showing another embodiment of the present invention.

The fluid bearing device according to another embodiment is inserted into the shaft mounting hole 12 of the housing 10, the shaft 21 having a fluid pressure generating protrusion 41 protruding a plurality along the periphery of the outer end surface; Finishing shaft 30 is the shaft installation hole 12 is inserted, the finish hole 30 so as to face and maintain a predetermined interval with the fluid pressure generating protrusion 41 of the shaft 21, and the Between the shaft 21 and the finish opening 30 is mounted to the finish opening 30 while maintaining a predetermined interval with the fluid pressure generating protrusion 41 of the shaft 21, the fluid pressure generated during the rotation of the shaft 21 It consists of a bearing member 40 supported by the fluid pressure generated by the projection (41).

The fluid bearing device of the above-described configuration has the same effect as the present invention, except that the present invention is to support the shaft 21 by generating air pressure on the bearing member 40 side, and the fluid bearing of the above configuration. The device is that air pressure is generated and supported on the axis 21 that is rotated.

In addition, in order to generate air pressure when the shaft 21 rotates, the fluid pressure generating protrusion 41 has an inclined surface proximate to the bearing member in a direction opposite to the rotation direction of the shaft.

Alternative Embodiment 2 of the Invention

This embodiment is a bearing in which no bearing groove is formed on the outer circumferential surface of the shaft-generally referred to as plain bearing. In the bearing, the bearing rotates the air at a high speed by the rotational force of the shaft in the gap between the outer surface of the shaft and the shaft installation hole, and the rotating air causes the bearing to act, which causes the aforementioned whirling phenomenon. .

Therefore, the fluid bearing device in the present embodiment is configured as in the present invention and the other embodiment 1 to support a plurality of places on the bottom of the shaft, thereby preventing the whirling phenomenon by allowing the shaft to rotate stably.

As described above, the present invention improves the structure of the fluid bearing device applied to the motor to eliminate the bearing groove, and instead of forming the pressure generating protrusion in the bearing member by milling, etc. Effective invention to reduce the cost effectively to improve the work efficiency, the air pressure generated in the bearing member to support a plurality of places on the bottom of the shaft to make the shaft rotate more stably and at the same time to prevent the whirling phenomenon, which is a characteristic of the fluid bearing to be.

Claims (9)

A fluid bearing device capable of generating a thrust pressure at an end surface of a shaft in a motor, A shaft inserted into the shaft installation hole of the motor housing; A closing tool for maintaining a predetermined distance from the end surface of the shaft so as to face each other and closing the shaft installation hole in which the shaft is inserted; And And a bearing member mounted to the finish to maintain a predetermined distance between the shaft and the finish, such that the bearing member is configured to support a plurality of opposing surfaces during rotation of the motor rotor. The method of claim 1, wherein the bearing member A fluid bearing device comprising a fluid pressure generating protrusion for generating a plurality of air pressure by forming a plurality of protrusions protruding along the periphery outside the surface facing the shaft. The method of claim 2, wherein the fluid pressure generating projections A fluid bearing device having an inclined surface proximate the shaft in the rotational direction of the shaft. The method of claim 1 or 2, wherein the axis is Fluid bearing device characterized in that it has a plurality of bearing grooves on the outer peripheral surface. The method of claim 1, wherein the bearing member is Fluid bearing device, characterized in that the circular plane. A fluid bearing device capable of generating a thrust pressure at an end surface of a shaft in a motor, A shaft inserted into the shaft installation hole of the motor housing, the shaft having a plurality of fluid pressure generating protrusions protruding along the periphery outside the end surface; Closing the shaft installation hole is inserted into the shaft, the closing tool to face the fluid pressure generating projection of the shaft facing a predetermined interval; And Maintain a predetermined interval between the shaft and the finish opening and the fluid pressure generating projection of the shaft is mounted to the finish, characterized in that it comprises a bearing member that is supported by the fluid pressure generated in the fluid pressure generating projections when the rotation of the motor rotation; Fluid bearing device. The method of claim 6, wherein the fluid pressure generating projections And a sloped surface proximate to the bearing member in a direction opposite to the rotational direction of the shaft. The method of claim 6, wherein the axis is Fluid bearing device characterized in that it has a plurality of bearing grooves on the outer peripheral surface. The method of claim 6, wherein the bearing member Fluid bearing device, characterized in that the circular plane.