KR100224609B1 - Apparatus for adjusting clearance in rotating axis for which fluid bearing is adapted - Google Patents

Abstract

The present invention is directed to a fluid bearing device having a back flow port for preventing leakage due to backflow to an outer diameter portion and backflow to an inner diameter portion by varying the position of the bent portion of the dynamic pressure generating groove formed in the thrust bearing supporting the thrust load. The present invention relates to a first fluid pressure generating unit and a second fluid pressure generating unit by varying the area to prevent leakage due to the reverse flow to the outer diameter portion, the reverse flow to the inner diameter portion to reduce the fluid pressure loss to reduce the rotational performance It is effective to prevent.

Description

A fluid bearing device having a backflow port {APPARATUS FOR ADJUSTING CLEARANCE IN ROTATING AXIS FOR WHICH FLUID BEARING IS ADAPTED}

The present invention relates to a fluid bearing device having a backflow port, and more particularly, to a leak and an inner diameter part by varying the position of a bent portion of a dynamic pressure generating groove formed in a thrust bearing supporting a thrust load. It relates to a fluid bearing device having a backflow port for preventing leakage due to the backflow of.

Recently, as information technology such as computer, audio system, video equipment, etc. and media industry have increased, the size of various devices mentioned above is miniaturized, and according to the miniaturization, there is a demand for components of devices with finer and more precise performance. In particular, a spindle motor drive of a hard disk (HDD), which is one of the storage devices for a computer, and a polygon mirror drive of a laser printer, a laser disk and a compact disc drive for an audio system, a VCR head and a camcorder for an imaging device. In general, the driving device of the motor rotates the rotating shaft and the rotating body which are coupled to the driving device at high speed, thereby storing and retrieving desired data and reproducing data. The rotating shaft rotates at a very high speed. Shaking, Shaking, Shaking of Shaft are the characteristics of the product during high speed rotation. All of these devices use bearings, one of the mechanical elements, to protect the problems caused by high-speed rotation, especially air or oil. Fluid bearing devices using oil are widely used.

Among these fluid bearing devices, the laser mirror's polygon mirror drive device, the HDD's spintle motor, and the VTR head drive device, which require ultra-precision and ultra-fast rotational performance, flow into the dynamic pressure generating groove of the thrust bearing to generate dynamic pressure. Some types of incompressible oils have superior rigidity than air.

Such a fluid bearing device is classified into a radial fluid bearing device for supporting radial loads and a thrust fluid bearing device for supporting thrust loads, among which a thrust fluid bearing device is again a thrust fluid bearing device. Various combinations can be achieved, such as the case where the shaft attached to the rotating body and the rotating body supporting the rotating body is fixed, and the shaft is fixed by pressing or the like, and the rotating body rotates to generate a predetermined fluid pressure.

1 is a view showing a conventional VTR head driving device, in which the VTR head driving device is largely rotatable an upper drum 20 having a head 10 for reading video and audio signals recorded on a VTR tape. ) And a lower drum 30, a center of rotation of the upper drum 20, and a thrust load of the upper drum 20, which are fixed while forming a predetermined inclination angle on the drum base (not shown) of the deck plate (not shown). In addition, it is press-fitted to the first cylindrical portion (hereinafter referred to as an axis; 40) having a predetermined diameter, and the second cylindrical portion of the disk shape having a herringbone-shaped first dynamic pressure generating groove (50b) on the upper surface (hereinafter referred to as It is called a thrust bearing; and it consists of 50 and the drive motor part 60,70.

A second dynamic pressure generating groove 40a having a herringbone shape is formed in the circumferential direction of the outer circumferential surface of the shaft 40, and dynamic pressure is generated by the second dynamic pressure generating groove 40a to generate the upper drum 20. The upper drum 20 has a shaft supporting member (hereinafter referred to as bushing) 80 having a diameter of several micrometers larger than the diameter of the inner circumferential surface of the shaft 40 so as to support the radial load generated during the high speed rotation. It is fixed.

The aforementioned drive motors 60 and 70 are composed of a stator motor 60 fixed to the upper surface of the shaft 40 and a rotor 70 seated on the upper drum 20. Reference numeral 95 denotes a stator transformer, and 90 denotes a rotary transformer spaced several micrometers from the stator transformer.

FIG. 2 is a view illustrating a first dynamic pressure generating groove and a shaft formed in the thrust bearing of FIG. 1, and two straight lines having a predetermined area are connected at an acute angle to an upper surface of the thrust bearing 50 so that the bent portion 50a is formed. A herringbone-shaped dynamic pressure generating groove 50b is formed, and the bent portion 50a is formed on a circumferential line D larger than the diameter of the shaft 40 and smaller than the diameter of the thrust bearing 50, and D is the thrust. It is formed in the bisector part of the bearing 50. As shown in FIG.

Referring to the accompanying drawings, the operation of the conventional VTR head driving device configured as described above is as follows.

First, the stator 60 is fixed to the shaft 40 of the drive motor, and the rotor 70 is fixed to the upper drum 20. When the power is applied to the drive motor, the upper drum is centered around the shaft 40. As the head 20 rotates, the head 10 installed in the upper drum 20 also rotates to read the video and audio signals of the video tape, and supports the thrust load of the upper drum 20 and the upper drum 20. In order to minimize the friction generated while rotating, a predetermined fluid flows into the herringbone-shaped first dynamic pressure generating groove 50b formed on the upper surface of the thrust bearing 50, so that the thrust bearing 50 and the upper drum 20 As it comes into contact, it rotates at high speed.

However, the fluid flowing into the herringbone-shaped first dynamic pressure generating groove which is formed in such a conventional thrust bearing and generates a predetermined fluid pressure in order to support the thrust load is subjected to the centrifugal force generated by the centrifugal force generated by the high speed rotation of the thrust bearing. As a result, there is a problem in that sufficient dynamic pressure is not generated to support the thrust load because the size of the fluid pressure decreases in response to the amount of leakage due to leakage to the outer diameter of the thrust bearing and not flowing into the bent portion of the thrust bearing.

Accordingly, the present invention has been made in view of such a conventional problem, and an object of the present invention is to change the position of the bent portion of the dynamic pressure generating groove having a herringbone shape formed in the thrust bearing, so that the fluid pressure loss due to the backflow of the fluid is reduced. It is to form the backflow port which prevented generation.

1 is a cross-sectional view showing a VTR head drive device to which a conventional fluid bearing device is applied.

FIG. 2 is a sectional view of the thrust bearing of FIG. 1. FIG.

3 is a sectional view showing a thrust bearing according to the present invention.

Figure 4 is a sectional view showing another embodiment according to the present invention.

Explanation of symbols for the main parts of the drawings

40: shaft 50: thrust bearing

50b: first dynamic pressure generating groove 100: first fluid pressure generating portion

110: second fluid pressure generating section

A fluid bearing device having a backflow port for achieving the object of the present invention is inserted into the first cylindrical portion, the first cylindrical portion having a predetermined length and a predetermined diameter, and the second cylinder is shorter than the diameter of the first cylindrical portion Predetermined fluid by a dynamic pressure generating groove in which a herringbone-shaped bent portion is formed in any one of a shaft formed by a portion, a support member which is formed in a shape opposite to the shaft, and a support member that is in contact with the shaft, and a support member corresponding to the second cylinder portion and the second cylinder portion. And a fluid pressure generating portion for generating pressure, wherein the bent portions are arranged at a predetermined angle on an arbitrary circumference formed to have a predetermined diameter on the second cylindrical portion, and the boundary surface and the circumference of which the first cylindrical portion and the second cylindrical portion meet each other are formed. The first fluid pressure generating portion is formed in the first interval, and the second fluid pressure generating portion is formed between the outer circumferential surface of the second cylindrical portion and the second gap formed by the circumference. Castle and a first fluid pressure-generating unit and the second area of the fluid pressure generating part is characterized not from the same first fluid pressure generating section and the second hydraulic pressure generation unit that prevents a backflow of the fluid.

Hereinafter, with reference to the accompanying drawings, a fluid bearing device having a backflow port of the present invention will be described.

3 is a plan view illustrating a thrust bearing in a fluid bearing device in which a backflow port is formed according to the present invention, and a duplicate description thereof will be omitted for the same parts as in the prior art, and the same reference numerals and the same names are used for the same parts as in the prior art. Let's use.

The thrust bearing (second cylindrical portion; 50) according to the present invention has a disc shape having a predetermined thickness and a predetermined diameter, and a hollow portion is formed at the center of the disc so that the shaft (first cylindrical portion; 40) is press-fitted. Between the part and the outer diameter of the thrust bearing 50, a first dynamic pressure generating groove 50b having a predetermined groove area in the shape of a herringbone is formed.

A virtual circle E is formed between the inner diameter A and the outer diameter B in the first dynamic pressure generating groove 50b formed in the thrust bearing 50.

When the circle E is viewed on the bisector of the inner diameter A and the outer diameter B, the interval between the inner diameters A and E is made to be the second interval (C), and the interval formed between the outer diameters B and E is to be the first interval (D). Among them, the second interval C is formed to be smaller than the first interval D, so that the first interval D and the second interval C and the first fluid pressure generator 100 described later are defined by E. , The groove areas K and G of the second fluid pressure generating unit 110 are determined.

In addition, the first dynamic pressure generating groove 50b has two straight lines ab and bc connected to E with a predetermined acute angle (β: β looks like an obtuse angle in FIG. 3 but is actually an acute angle) to form a bent portion 50a. In the portion e which is rotated by a predetermined angle, two straight lines de and ef are connected to E at a predetermined acute angle β to form a bent portion e, and the first fluid pressure formed by lines a, b, e and d It is formed by the generation part (part hatched by the dot; 100) and the 2nd fluid pressure generation part (part hatched by the hatched line) 110 formed by the lines b, c, f, and e.

Herein, when the area of the first fluid pressure generating unit 100 having an arc and a straight line is K, and the area of the second fluid pressure generating unit 110 having an arc and a straight line is G, K is obtained. , G is formed to have a relationship of KG, so that the first fluid pressure generating part 100 serves as a backflow port.

Referring to the accompanying drawings, the action of the fluid bearing device having a backflow port of the present invention configured as described above is as follows.

First, the stator 60 is fixed to the shaft 40 of the drive motor, and the rotor 70 is fixed to the upper drum 20. When the power is applied to the drive motor, the upper drum is centered around the shaft 40. As the 20 is rotated, the head 10 provided in the upper drum 20 is also rotated to read the video signal and the audio signal of the video tape.

At this time, in order to support the thrust load of the upper drum 20 and minimize the friction generated while the upper drum 20 rotates, the first dynamic pressure generating groove 50b of the herringbone shape formed on the upper surface of the thrust bearing 50 is formed. The fluid introduced into the first fluid pressure generating unit 100 and the second fluid pressure generating unit 110 may be a bending portion 50a where the first fluid pressure generating unit 100 and the second fluid pressure generating unit 110 meet each other. ) Are combined to generate a predetermined fluid pressure. At this time, since the groove area of the first fluid pressure generating unit 100 is larger than the groove area of the second fluid pressure generating unit 110, the fluid inflow amount and the magnitude of the fluid pressure are shown. As shown in the fluid pressure graph, the first fluid pressure generator 100 may be enlarged to compensate for the loss of the fluid flowing back due to the centrifugal force.

FIG. 4 illustrates another embodiment of the present invention, in which the thrust bearing 50 is press-fitted to the shaft 40 in the embodiment of FIG. 3, but the embodiment of FIG. 4 shows that the thrust bearing 50 has an upper drum (not shown). ), Which is attached to the shaft and is rotatable with respect to the shaft 40. In such an embodiment, a fluid that flows backward by leaking into the inner diameter A of the thrust bearing 50 may be leaked, thereby reducing the fluid pressure. .

The first interval D is set smaller than the second interval C among the second interval C formed by the inner diameters A and E and the first interval D formed by the outer diameters B and E, and E is set as described above. The first fluid pressure generating portion (hatched with dots; 100) and the second fluid pressure generating portion (hatched with diagonal lines) having a smaller area than the first fluid pressure generating portion 100 having the same acute angle on the top. ) To reduce the amount of fluid leaked by the second fluid pressure generating unit 110 by the reverse flow to the inner diameter portion.

Since the thrust bearing of the present invention has a wide range of applications, and the configuration of the motor to which the thrust bearing is applied is also very diverse, it can be easily applied to a thrust bearing subjected to a thrust load within the scope of the claims of the present invention. There will be.

Further, in one embodiment of the present invention, the shaft and the thrust bearing may be press-fitted separately, but the shaft and the thrust bearing may be integrally manufactured using the same member.

As described in detail above, the area of the first fluid pressure generating portion and the second fluid pressure generating portion is varied to prevent leakage due to backflow to the outer diameter portion and leakage due to backflow to the inner diameter portion, thereby reducing the fluid pressure loss, thereby rotating performance. It is effective in preventing a decrease.

Claims (5)

A first cylindrical portion having a predetermined length and a predetermined diameter; A shaft inserted into the first cylindrical portion and formed of a second cylindrical portion having a length greater than the diameter of the first cylindrical portion and shorter than the first cylindrical portion; A support member formed in a shape opposite to the shaft and facing the shaft; And a fluid pressure generating unit for generating a predetermined fluid pressure by a dynamic pressure generating groove having a herringbone-shaped bent portion formed in one of the second cylindrical portion and the support member corresponding to the second cylindrical portion. The bent portion is arranged at a predetermined acute angle on any circumference formed on the second cylindrical portion, and a first fluid pressure generating portion is formed at a first interval formed between the boundary surface where the first cylindrical portion and the second cylindrical portion meet and the circumference. And a second fluid pressure generating part is formed between an outer circumferential surface of the second cylindrical part and a second gap formed between the circumference, and the area of the first fluid pressure generating part and the second fluid pressure generating part are not equal to each other. A fluid bearing device having a back flow port, wherein the fluid is prevented from flowing back from the first fluid pressure generator and the second fluid pressure generator. The fluid bearing with a back flow port according to claim 1, wherein a first interval formed in the second cylindrical portion to prevent back flow of the fluid from the second fluid pressure generating portion is smaller than the second interval. Device. The fluid bearing device according to claim 1, wherein the first interval is larger than the second interval to prevent the backflow of the fluid from the first fluid pressure generating portion. The fluid bearing device according to claim 1 or 2, wherein the second cylindrical portion is press-fitted into the first cylindrical portion. 4. The fluid bearing device according to claim 3, wherein the second cylindrical portion is rotatably inserted into the first cylindrical portion.