KR100196935B1 - Thrust bearing system - Google Patents

Abstract

The present invention relates to a thrust bearing device, and more particularly, the fluid pressure is effectively and stably distributed by irregularly arranging the arrangement and shape of the fluid inlet grooves (dynamic pressure generating grooves) in the form of spiral grooves. It relates to a thrust bearing device as possible. To this end, the present invention provides a predetermined center of rotation shaft, a sleeve into which the shaft is fitted, a bearing bracket for fixing the sleeve, and a first dynamic pressure of a predetermined form to be fixed to the sleeve to float the shaft. A bearing apparatus comprising a thrust bearing having a generating groove and a second dynamic pressure generating groove formed in an outer diameter portion of the shaft fitted to the sleeve to contactlessly rotate the sleeve and the shaft. The first dynamic pressure generating groove formed in the thrust bearing is characterized by consisting of spiral grooves having irregular arrangement intervals and shapes.

Description

Drust Bearing

The present invention relates to a thrust bearing device, and more particularly, the fluid pressure is effectively and stably distributed by irregularly arranging the arrangement and shape of the fluid inlet grooves (dynamic pressure generating grooves) in the form of spiral grooves. It relates to a thrust bearing device as possible.

In recent years, as information technology such as computers, audio systems, video devices, and the like increase in the technology of the media industry, the size of the various devices is downsized, and according to the miniaturization, there is a demand for parts of devices having finer and more precise performance. , Spindle motor drive of hard disk (HDD) which is one of the storage devices for computer and polygon mirror drive of laser printer, laser disk and compact disc drive for audio system, VCR head and camcorder for video equipment The device and the like rotate and rotate the rotating shaft and the rotating body, which are commonly connected to the driving device, to store and search for desired data and to play data. At this time, the rotating shaft rotates at a very high speed. And shaft vibration, shaft vibration, etc. As a result, all of these machines use bearings, which are one of the mechanical elements, to protect the problems caused by high-speed rotation. Bearing devices are widely used.

When describing a polygon mirror driving device for irradiating a laser beam to the photosensitive drum of the laser printer of the drive device including such a conventional thrust bearing device as an example.

1 is a view illustrating a polygon mirror driving apparatus of a laser printer, in which a through hole having a predetermined diameter is formed in a bearing bracket 10, and a sleeve 20 as shown in the through hole is fitted into the through hole. The bearing bracket 10 is fastened and fixed by the fixing screw 22 or the like, and the shaft 30 is rotatably inserted into the sleeve 20.

The lower end portion 30b of the shaft 30 is interviewed with the thrust bearing 50 receiving the vertical thrust load of the shaft 30, and the upper surface of the thrust bearing 50 has a predetermined shape, for example, spiral groove. The first dynamic pressure generating groove 50a (FIG. 2) of the woob shape is formed, and the first dynamic pressure generating groove 50a starts from the circumferential surface of the upper surface of the thrust bearing 50 to the center of the upper surface and has a predetermined depth. The first dynamic pressure generating groove 50a is precisely processed to a depth of several μm by etching or the like.

As such, the thrust bearing 50 having the first dynamic pressure generating groove 50a is supported by the thrust pedestal 40 again, and the thrust pedestal 40 is the sleeve 20 and the screw 42. And the like, and the hub 70 is press-fitted to the middle portion of the shaft 30 and fixed to the shaft 30, and the motor 60, which is only partially shown, is joined to the hub 70, and the shaft 30 is joined to the shaft 30. Rotates with the motor 60, and the polygon mirror 80 is attached to the hub 70.

In addition, the sleeve 20 has a vent hole 20a formed at the portion where the thrust bearing 50 and the shaft 30 are interviewed, and the shaft 30 is inserted into the hole of the sleeve 20. A second dynamic pressure generating groove 30a having a herringbone shape is formed in the shaft 30 or the sleeve 20 of the surface in which the inner diameter of the sleeve 20 faces, and thus, the second dynamic pressure generating groove 30a is formed. The groove angle is generally about 30 degrees, and the depth of the second dynamic pressure generating groove 30a is about several micrometers.

Referring to Figures 1 and 2 attached to the operation of the polygon mirror driving device of the laser printer having a conventional thrust bearing device as described above are as follows.

First, when power is applied to the motor 60, which is only partially shown, the motor 60 gradually increases its angular velocity in a state where the angular velocity is 0, and reaches a maximum angular velocity after a predetermined time, whereby the angular velocity becomes constant. 30) rotates at the same angular speed as the motor.

Equation 1 shows the relationship between the fluid pressure, the magnetic weight of the shaft and the load of the shaft, the gap area and the axial angular velocity.

[Equation 1]

P: Fluid pressure to float the shaft

V: axis angular velocity

F: shaft weight and shaft load (kg _f )

S: clearance area between thrust bearing and shaft

Applying Equation 1 to FIG. 2, the fluid flows into the A (or C) portion of the thrust bearing 50, which is the start of the first dynamic pressure generating groove 50a by the rotation of the shaft 30. A fluid pressure P is formed to flow into the portion B, which is the center of the first dynamic pressure generating groove 50a, and to float the shaft 30 in the central portion B of the first dynamic pressure generating groove 50a. ) And the area S of the lower end portion 30b of the shaft, and the middle and axial loads F of the shaft are unchanged, so that the fluid pressure increases in proportion to the angular velocity V of the shaft 30, When the predetermined pressure is reached and the fluid pressure P becomes larger than the self-weight of the shaft and the axial load F, the shaft 30 forms a constant gap from the first dynamic pressure generating groove 50a and the first dynamic pressure generating groove ( After injury to the top of 50a), equilibrium is achieved.

By the way, in the thrust bearing device acting as described above to float the rotating shaft, the first dynamic pressure generating groove of the spiral groove type is usually formed in a single shape spiral as shown in detail in FIG. There was a problem that generates the maximum fluid pressure only in the center. That is, the fluid pressure generated in the first dynamic pressure generating groove 50a of the fluid bearing device starts to be generated on the outer circumferential surface A of the first dynamic pressure generating groove 50a in the form of a spiral groove, and then increases, and then the center portion C thereof. Since the axis of rotation causes the shaft to float and rotate due to the fluid pressure, shaft shaking, shaft shaking, and shaft vibration are generated, which lowers the rotational stability, causing problems such as product malfunction, performance degradation, and shortened life. .

In addition, the spiral grooves 50a constituting the first dynamic pressure generating groove of the conventional thrust bearing device are arranged at regular intervals to generate a fluid pressure of a predetermined size at regular intervals as shown in FIG. 3 (B). There is a problem that does not properly distribute the fluid pressure.

Furthermore, since the spiral grooves forming the first dynamic pressure generating groove of the conventional thrust bearing device are formed in the same area, depth and shape, as shown in FIGS. 3 (C) to 3 (E), The final fluid pressure (FIG. 3) formed by combining the fluid pressure (FIG. 3C) formed by 50a and the fluid pressure (FIG. 3D) formed by the place 50b other than the groove. In (E), there is a problem in that the bending region P is formed and the rotating shaft vibrates at the bending portion of the fluid pressure.

The present invention has been made to solve the above problems, the spiral inlet groove of the fluid inlet groove (dynamic pressure generating groove; hereinafter, the meaning of the fluid inlet groove and the dynamic pressure generating groove) of the thrust bearing device is described. It is an object of the present invention to provide a thrust bearing device in which the arrangement of the grooves and the shape of the area and the depth are irregular, so that the fluid pressure can be effectively and stably distributed so that the rotating shaft can rotate at optimum conditions.

1 is a cross-sectional view showing a polygon mirror driving device using a conventional thrust bearing device,

Figure 2 is a configuration diagram showing the form of the conventional pressure bearing device and the fluid pressure generated in the bearing device,

3 is a plan view showing in detail the shape of a spiral groove formed in a conventional thrust bearing device;

4 is a configuration diagram showing the configuration of the thrust bearing device and the fluid pressure generated in the bearing device according to the present invention;

5 and 6 are exemplary views showing the arrangement and form of spiral grooves formed in the thrust bearing device of the present invention.

Explanation of symbols for the main parts of the drawings

10: bearing bracket 20: sleeve

30: rotating shaft 100: thrust bearing

110: first dynamic pressure generating groove 110a: spiral groove

110e..110h: Spiral grooves with different areas and depths

Drust bearing device according to the present invention to achieve the above object,

A predetermined center of rotation shaft, a sleeve to which the shaft is fitted, a bearing bracket for fixing the sleeve, and a first dynamic pressure generating groove of a predetermined form to be fixed to the sleeve to float the shaft; A bearing apparatus comprising a thrust bearing and a second dynamic pressure generating groove formed in an outer diameter portion of the shaft fitted to the sleeve to contactlessly rotate the sleeve and the shaft.

The first dynamic pressure generating groove formed in the thrust bearing is characterized in that it is composed of spiral grooves whose arrangement intervals are irregularly arranged.

In a preferred embodiment of the present invention, the area and depth of each of the spiral grooves may be the same.

In a preferred embodiment of the present invention, the area and depth of each of the spiral grooves may not be the same.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the thrust bearing device according to the present invention. For convenience of description, the same reference numerals and the same names will be used for the same member as the conventional member.

4 is a cross-sectional view showing a part of the polygon mirror driving apparatus of the laser printer using the thrust bearing device according to the present invention, the parts not shown in the drawings are the same as the conventional configuration will be omitted.

A through hole having a predetermined diameter is formed in the lower bearing bracket 10, and a sleeve 20 as shown in the through hole is fitted therein, and then is fastened to the bearing bracket 10 by a fixing screw 22 or the like. It is fixed and the shaft 30 is rotatably inserted in the sleeve 20.

In addition, a second dynamic pressure generating groove 30a having a herringbone shape is formed at a side surface of the shaft 30 inserted into the sleeve 20 so that the sleeve 20 and the shaft 30 can be rotated without contact. have. On the other hand, the gap between the sleeve 20 and the shaft 30 is very finely processed to several micrometers.

The contact surface with the lower surface 30b of the shaft 30 is provided with a thrust bearing 100 that supports the shaft self-weight and the axial load and floats the shaft 30, and the thrust bearing 100 is sleeved again. It is fixed by the 20 and the screw 24 etc.

Spiral grooves (hereinafter, the first dynamic pressure generating groove and the spiral groove are used in the same sense) are formed on the upper surface of the thrust bearing 100 to form the first dynamic pressure generating groove 110. The arrangement intervals d1, d2, d3, d4 of the spiral groove 110 are not constant as shown in FIGS. 4 and 5. Here, the area and depth of the non-uniformly arranged spiral grooves 110 may be the same as shown in FIG. 5, or may not be the same as shown in FIG. 6. The shape of the spiral groove 110 formed as described above may be appropriately set in consideration of design aspects.

In Fig. 5, the spiral grooves indicated by reference numeral 110a preferably indicate the same shape, and the reference numeral d1..d4 preferably denotes a state in which the spiral grooves 110a are irregularly arranged. In Fig. 6, the spiral grooves indicated by the member numbers 110e..110h are preferably shown to have different areas and depths, and the member d5..d8 denotes these spiral grooves 110e..110h. ) Is preferably an irregularly arranged state.

When explaining the operation of the thrust bearing device according to the present invention configured as described above with reference to Figures 4 and 6 as follows.

First, when power is applied to a motor (not shown) and the motor starts to rotate, the shaft 30 coupled to the motor also rotates at the same angular speed as the motor, in which case the lower end of the shaft corresponds to the rotational speed of the shaft 30. The vortex is formed in the 30b, and the vortex is introduced while turning inward through the first dynamic pressure generating groove 110 of the upper surface of the thrust bearing 100 facing the lower end portion 30b of the shaft. As the fluids gather, they generate a certain amount of fluid pressure.

That is, as shown in FIG. 5, when the vortex flows into the spiral grooves 110a having the same size and depth and irregular array intervals d1..d4, the fluid pressure as shown is shown. The irregularly arranged spacings (d1..d4) are properly distributed and formed, and thus the fluid pressures dispersed by the irregularly arranged spiral grooves (110a) finally reach the center of the thrust bearing. Generate a fluid pressure without a bend zone as shown in FIG. Therefore, when the shaft 30 rises and rotates due to the fluid pressure generated as described above, the shaft 30 rotates in an optimal stable state.

As another embodiment of the present invention, as shown in FIG. 6, the vortices are introduced into spiral grooves 110e .. 110h having irregular shapes (sizes and depths) and arrangement intervals d1..d4. In the case of turning, as shown, different pressures of fluid are formed appropriately in every irregular arrangement interval d5..d8, and thus irregularly arranged and shaped in different spiral grooves 110e .. The fluid pressure dispersed by 110h) ultimately generates a fluid pressure without bending region as shown in FIG. 4 near the center of the thrust bearing. Therefore, when the shaft 30 rises and rotates due to the fluid pressure generated as described above, the shaft 30 rotates in an optimal stable state.

As described in detail above, the thrust bearing device according to the present invention, by irregularly arranging the spacing and shape of the spiral spiral grooves constituting the first dynamic pressure generating groove so that the fluid pressure is effectively dispersed, the rotating shaft rotates to the optimum condition. It has the effect of making it possible. As such, the present invention provides the advantage of improving the performance, life and reliability of the product.

Claims (5)

A predetermined center of rotation shaft, a sleeve to which the shaft is fitted, a bearing bracket for fixing the sleeve, and a first dynamic pressure generating groove of a predetermined form to be fixed to the sleeve to float the shaft; A bearing apparatus comprising a thrust bearing and a second dynamic pressure generating groove formed in an outer diameter portion of the shaft fitted to the sleeve to contactlessly rotate the sleeve and the shaft. And a first dynamic pressure generating groove formed in the thrust bearing, wherein the first dynamic pressure generating groove is formed of spiral grooves having irregular arrangements thereof. The thrust bearing device according to claim 1, wherein the spiral grooves have the same shape. The thrust bearing device according to claim 1, wherein the spiral grooves are not the same shape. 4. A thrust bearing device according to claim 3, wherein the area of the spiral grooves is different. 4. A thrust bearing device according to claim 3, wherein the spiral grooves have different depths.