KR100208014B1 - Thrust bearing - Google Patents

Abstract

The present invention relates to a thrust bearing device, and more particularly, by forming the fluid inlet groove into a spiral spiral groove to increase the fluid inflow into the fluid inlet groove (dynamic pressure generating groove) formed in the thrust bearing device. The present invention relates to a thrust bearing device having an increased area. 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 a single vortex spiral groove. Thus, the present invention provides the advantage of increasing the dynamic pressure generating area.

Description

Drust Bearing

The present invention relates to a thrust bearing device, and more particularly, by forming the fluid inlet groove into a spiral spiral groove to increase the fluid inflow into the fluid inlet groove (dynamic pressure generating groove) formed in the thrust bearing device. The present invention relates to a thrust bearing device having an increased area.

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) is formed in the shape of a groove or herringbone groove, 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. The first dynamic pressure generating groove 50a is precisely processed to a depth of several micrometers 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.

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 at 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 remain unchanged, so that the fluid pressure increases in proportion to the angular velocity V of the shaft 30, whereby the shaft 30 is predetermined. When the number of revolutions per minute 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 50a. After the injury to the top of the), equilibrium is achieved.

However, in the thrust bearing device which floats the rotating shaft by acting as described above, the first dynamic pressure generating groove of the spiral groove type is generally formed in the shape of a vane wing as shown in detail in FIG. There was a problem of generating a fluid pressure. 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, in the conventional thrust bearing device, since the total size of the first dynamic pressure generating groove of the spiral groove type is small, there is a problem in that the amount of fluid introduced is small. Therefore, the conventional thrust bearing device does not effectively raise a predetermined rotation axis.

Furthermore, in the conventional thrust bearing device, it is very difficult to form the peak portion of each dynamic pressure generating groove during the etching operation for forming the first dynamic pressure generating groove in the form of a spiral groove.

The present invention has been made to solve the above problems, a plurality of spiral grooves that are 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 It is an object of the present invention to provide a thrust bearing device in which the shape of the groove is formed by improving the shape of a spiral spiral groove to increase the dynamic pressure generating area and to facilitate manufacturing.

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,

Figures 5a, b are plan views showing various forms of continuous spiral spiral grooves formed in the present thrust bearing device.

* Explanation of symbols for main parts of the drawings

10: bearing bracket 20: sleeve

30: rotating shaft 100: thrust bearing

110: first dynamic pressure generating groove

In order to achieve the above object, a thrust bearing device according to the present invention includes a predetermined center of rotation shaft, a sleeve into which the shaft is fitted, a bearing bracket for fixing the sleeve, and fixed to the sleeve. A thrust bearing in which a first dynamic pressure generating groove of a predetermined form is formed so as to float the shaft, and a second dynamic pressure generating groove which is formed in an outer diameter portion of the shaft fitted to the sleeve to contactlessly rotate the sleeve and the shaft; In the bearing device comprising a, the first dynamic pressure generating groove formed in the thrust bearing is characterized in that it consists of a single helical spiral groove.

In a preferred embodiment of the present invention, the single vortex spiral groove can be gradually narrowed in width and depth, or all the same, towards the center thereof.

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.

The upper surface of the thrust bearing 100 is formed with a first dynamic pressure generating groove 110 made of a single spiral spiral groove. Here, the single helical spiral groove, which is the first dynamic pressure generating groove 110, is gradually directed to the center of the thrust bearing 100, as shown in FIG. As shown in FIG. 5B, the width and the depth may be the same as in FIG. 5A.

Referring to Figure 4 and 5 the operation of the thrust bearing device according to the present invention configured as described above are 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. A vortex is formed at 30b and the vortex formed toward the center through the periphery of a single vortex helical groove which is the first dynamic pressure generating groove 110 of the upper surface of the thrust bearing 100 facing the lower end 30b of the shaft. It is introduced while turning and generates a fluid pressure in the form of a parabola, preferably in the form of a logarithmic function, as shown in FIG. This will be described below with reference to FIG. 5.

That is, the vortex fluid formed as described above flows in the periphery of the single helical spiral groove which is the first dynamic pressure generating groove 110 as shown by the arrow. Here, the amount of fluid introduced is proportional to the total volume of a single vortex helical groove. Therefore, the fluid pressure according to the present invention is larger than the fluid pressure (see FIG. 3) formed by the conventional grooves, which is the first dynamic pressure generating groove 110 of the present invention in the form of a single spiral spiral groove. This is because the amount of fluid introduced thereto increases. As shown in FIG. 5A, a thrust bearing device having a first dynamic pressure generating groove 110 made of grooves having a shape in which the width and depth thereof gradually decrease toward the center of the thrust bearing 100 is generated. The fluid pressure is inclined more than the fluid pressure generated in the thrust bearing device having the first dynamic pressure generating groove 110 'composed of grooves of a constant shape anywhere in width and depth as shown in FIG. 5B. Although more steep in terms of design, it may be preferably selected and used in terms of design.

As described in detail above, the thrust bearing device according to the present invention has an effect of increasing the fluid pressure per unit area by making the first dynamic pressure generating groove a single spiral spiral groove so that the dynamic pressure generating area is increased. In addition, the present invention has the advantage that the manufacturing of the first dynamic pressure generating groove in the form of a single helical spiral groove groove is easy.

Claims (3)

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 generating groove of a predetermined form to be fixed to the sleeve to float the shaft; A bearing device comprising a thrust bearing and a second dynamic pressure generating groove formed in an outer diameter portion of the shaft fitted to the sleeve, the second dynamic pressure generating groove for contactlessly rotating the sleeve and the shaft. The first dynamic pressure generating groove is a thrust bearing device, characterized in that the single helical spiral groove. 2. A thrust bearing device according to claim 1, wherein said single helical spiral groove is gradually narrowed in width and depth toward the center thereof. 2. A thrust bearing device according to claim 1, wherein the width and depth of the single helical spiral groove is the same in all positions.

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