JPH10281141A - Connected type dynamic pressure generator - Google Patents

Abstract

(57) Abstract: Provided is a connection-type dynamic pressure generating device capable of uniformly distributing head fluid pressure concentrated on a bent portion of a dynamic pressure generating groove and stably rotating at a high speed. SOLUTION: In a thrust bearing or a radial bearing, a large number of bent portions 60, 160 of dynamic pressure generating grooves 135, 235 are continuously connected by connecting grooves 48, 148 and concentrated at the bent portions. To disperse the fluid pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting type dynamic pressure generating device, and more particularly, to a bent portion of a dynamic pressure generating groove constituting a radial bearing or a thrust bearing and a connecting groove interposed between the bent portion. And to a connected dynamic pressure generating device.

[0002]

2. Description of the Related Art In general, a head drive of a video tape recorder, a scanner motor and a camcorder drive motor as a polygon mirror drive of a laser printer have been progressively increased in density and reduced in size. The driving device requires a bearing that can rotate precisely and stably at a very high speed, and a fluid bearing is used.

In order to minimize the frictional force that hinders the rotation of the rotating shaft of such a fluid bearing, various types of dynamic pressure generating grooves such as a spiral dynamic pressure generating groove or a herringbone-shaped dynamic pressure generating groove are used. Is being developed. FIG. 4 is a developed view showing a dynamic pressure generating groove of a conventional fluid bearing device and a fluid pressure distribution graph.

As shown in the figure, the vortex formed on the outer peripheral surface of the rotating shaft 30 by the rotation of the rotating shaft 30 causes the first groove 4 to rotate.
0 and the second groove 45 uniformly flow into the second groove 45 and meet at the bent portion 60. The fluid pressure distribution formed at this time has a shape like a secondary parabola having a vertex A at the bent portion 60, and the vertex A is a head fluid pressure for floating the rotating shaft 30. Rotary axis 3
0 is the bushing part 25 due to the fluid pressure thus generated.
And rotate without contact.

[0005]

However, in the conventional dynamic pressure generating groove, since the area where the head fluid pressure generated at the vertex A acts on the rotating body is extremely small, the force for supporting the rotating shaft is also reduced, and the rotating pressure is reduced. There is a problem in that the performance of a product requiring ultra-precision is deteriorated due to a sensitive response to a minute external impact or vibration of the shaft, accompanied by a swing or vibration of the rotating shaft.

Accordingly, the present invention has been devised to solve the above problems, and has as its object to uniformly distribute the head fluid pressure concentrated on the bent portion of the dynamic pressure generating groove. It is an object of the present invention to provide a connection type dynamic pressure generator capable of stably rotating at a high speed.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotating shaft having a plurality of first dynamic pressure generating grooves formed on an outer peripheral surface thereof and an inner surface of a through hole having a through hole formed therein. A sleeve formed with a bushing portion protruding therefrom, and a thrust bearing disposed opposite to an end of the through hole of the sleeve, the first dynamic pressure generating groove and the bushing when the rotating shaft is inserted into the through hole. The radial bearings face each other at predetermined intervals, and a plurality of second dynamic pressure generating grooves are formed on the surface of the thrust bearing facing the end face of the rotating shaft. This is achieved by an articulated dynamic pressure generator interconnected to distribute the pressure.

According to another feature of the present invention, a fixed shaft, a cylindrical thrust bearing inserted and fixed to the fixed shaft and having a plurality of dynamic pressure generating grooves formed on an end face thereof, are opposed to the end face at a predetermined interval. A drum on which a signal reading head is rotatably inserted into a fixed shaft, and wherein the dynamic pressure generating groove is interconnected to disperse the head fluid pressure. You.

Preferably, the first dynamic pressure generating groove includes a first groove, a second groove connected to the first groove at a bent portion, and another bent portion of the first dynamic pressure generating groove adjacent to the bent portion. And a connecting groove connecting the curved portion, wherein the first and second grooves each form an acute angle with the connecting groove. Preferably, the connection grooves are connected continuously along the circumferential direction of the rotation shaft.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. FIG.
1 is a sectional view showing a polygon mirror driving device of a laser printer to which the fluid bearing device of the present invention is applied.

Referring to FIG. 1, the first dynamic pressure generating groove 235 of the radial bearing is formed on one side of the rotating shaft 30 or the bushing portion 25. Form. That is, a plurality of herringbone-shaped first dynamic pressure generating grooves 235 are formed at equal intervals on the outer peripheral surface of the rotary shaft 30 corresponding to the bushing portion 25, and the first dynamic pressure is generated by the own weight and load applied to the rotary shaft 30. The groove area and the number of the grooves 235 are determined. The first dynamic pressure generating groove 235 is formed by turning, etching, and CVD deposition.

On the other hand, a sleeve 20 having a through hole formed therein is inserted and fixed on one side of the bearing bracket 10, and a thrust bearing 50 is inserted and fixed on the sleeve 20 on the other side. Sleeve 20
Is inserted into the through hole. In addition, thrust bearing 5
No. 2, ie, a herringbone-shaped and spiral-shaped second surface for supporting the thrust load of the rotating shaft 30 to float the rotating shaft 30 on the surface facing the lower end surface of the rotating shaft.
A dynamic pressure generating groove 50a is formed.

A hub 70 is pressed into the rotating shaft 30 to rotate the rotating shaft 30 at a predetermined number of revolutions. The hub 70 is provided with a plate 80 and a polygon mirror 90 for reflecting the laser beam to the photosensitive drum. . FIG. 2 is a developed view and a fluid pressure distribution graph showing a dynamic pressure generation groove of the fluid bearing device according to the present invention.

As shown in FIG. 2, according to the present invention,
The first groove 40 and the second groove 45 of the first dynamic pressure generation groove 235 are symmetrical with each other while forming an acute angle (β = 30 °) with respect to the midpoint F between D and E at both ends of the bushing portion 25. , The two grooves are connected by a bent portion 60. The first dynamic pressure generating grooves 235 are connected to each other through the connecting grooves 48 at the bent portions 60 and are connected to each other along the circumferential direction of the rotating shaft 30.

Hereinafter, the operation of the embodiment according to the present invention will be described. First, when power is applied and the plate 80 starts rotating, the polygon mirror 90 and the rotating shaft 30 rotate simultaneously at the same speed. Therefore,
Fluid flows into the first and second grooves 40 and 45 of the dynamic pressure generating groove 235 formed on the outer peripheral surface of the rotating shaft 30, and the flowed fluid turns at the bent portion 60 where both grooves are connected. Concentrate while

At this time, according to the present invention, the fluid flowing through the first and second grooves 40 and 45 is bent.
And the fluid is discharged through the connection groove 48, whereby the head fluid pressure is significantly reduced. That is, as shown in the fluid pressure distribution graph of FIG. 2, the fluid pressure is dispersed in B and C, and the fluid pressure is reduced in proportion to the width of the connection groove 48. As a result, the fluid pressure distribution is Is distributed throughout.

Preferably, the width of the connecting groove 48 is formed at a maximum in order to significantly reduce the pressure of the fluid flowing into the dynamic pressure generating groove 235 at the head portion. FIG. 3 is a perspective view showing another embodiment to which the dynamic pressure generating groove of the fluid bearing device of the present invention is applied. As shown, the dynamic pressure generating groove 135
Is a thrust bearing 15 fixed to the fixed shaft 130.
The cross section is formed on any one side of the cross section of the drum 170 and the cross section of the drum 170 opposed to the cross section. Here, the case where the cross section is formed on the end face of the thrust bearing 150 will be described as an example.

A drum 170 provided with a head for reproducing video and audio signals recorded on a VTR tape is rotatably inserted into a fixed shaft 130, and a thrust bearing 150 is formed with a through hole to form a fixed shaft 130. Press-fit and fixed. Therefore, the lower section of the drum 170 faces the dynamic pressure generating groove 135 formed in the upper section of the thrust bearing 150.

A dynamic pressure generating groove 135 is formed in an upper cross section of the thrust bearing 150 so that the dynamic pressure generating groove 13 is formed.
5, the first groove 140 and the second groove 145 have an acute angle,
Preferably, the two grooves are connected by a bent part 160 symmetrically with each other at 30 °. Also, each dynamic pressure generating groove 135
Are connected to each other through a connection groove 148 at a bent portion 160, and the connection groove 148 is formed in a circular shape having a predetermined diameter around the fixed shaft 130.

Hereinafter, the operation according to another embodiment of the present invention configured as described above will be described. When the power is applied and the drum 170 starts rotating, the fluid flows into the first and second grooves 140 and 145 of the dynamic pressure generating groove 135 formed in the upper cross section of the thrust bearing 150,
The inflowing fluid converges while turning at the bent portion 160 where both grooves are connected.

At this time, according to the present invention, the fluid flowing through the first and second grooves 140 and 145 is bent.
By adjusting at 60 and discharging through the connecting groove 148, the head fluid pressure is significantly reduced. That is,
The fluid pressure is reduced in proportion to the width of the connection groove 148, and the distribution of the fluid pressure is dispersed as a whole. Preferably, the width of the connection groove 148 is formed at a maximum in order to significantly reduce the pressure of the fluid flowing into the dynamic pressure generation groove 135 at the head portion. As described above, the first dynamic pressure generating groove 2
Thrust bearing 1 as well as the fluid pressure dispersed at 35
The fluid pressure acts evenly on the fifty dynamic pressure generating grooves 135.

Although the preferred embodiments of the present invention have been described in detail, those skilled in the art to which the present invention pertains have the spirit and scope of the present invention defined in the appended claims. The present invention can be variously modified or changed without departing from the present invention. For example, the width of the connection groove can be variously changed as long as the bearing can maintain its original function.

[0023]

As described above, according to the connection type dynamic pressure generating device of the present invention, the fluid which is continuously connected between the bent portions of the dynamic pressure generating groove by the connecting groove and concentrated at the bent portion is provided. By dispersing the pressure, it is possible to stably rotate even when a minute external impact or vibration is applied to the rotating shaft, and there is an advantage that the rotation safety is improved and the product performance is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a polygon mirror driving device of a laser printer to which a fluid bearing device of the present invention is applied.

FIG. 2 is a development view and a fluid pressure distribution graph showing a dynamic pressure generating groove of the fluid bearing device according to the present invention.

FIG. 3 is a perspective view showing another embodiment to which the dynamic pressure generating groove of the fluid bearing device of the present invention is applied.

FIG. 4 is a developed view and a fluid pressure distribution graph showing a dynamic pressure generating groove of a conventional fluid bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bearing bracket 20 Sleeve 25 Bushing part 35, 135 Dynamic pressure generating groove 30 Rotating shaft 40, 140 First groove 45, 145 Second groove 48, 148 Connecting groove 50, 150 Thrust bearing 50a Second dynamic pressure generating groove 60, 160 Folded portion 70 Hub 80 Plate 90 Polyhedral mirror 130 Fixed shaft 170 Drum 235 First dynamic pressure generating groove

Claims (8)

[Claims] A rotary shaft having a plurality of first dynamic pressure generating grooves formed on an outer peripheral surface thereof; a sleeve having a through hole formed therein and a bushing portion projecting from an inner side surface of the through hole; A thrust bearing not opposed to an end of the through hole of the sleeve, wherein the first dynamic pressure generating groove and the bushing portion face each other at a predetermined interval when the rotating shaft is inserted into the through hole. A radial bearing is formed, and a plurality of second dynamic pressure generating grooves are formed on a surface of the thrust bearing facing an end surface of the rotating shaft. The first dynamic pressure generating grooves disperse a head fluid pressure. A connection type dynamic pressure generator characterized by being interconnected. 2. The first dynamic pressure generating groove includes a first groove, a second groove connected to the first groove at a bent portion, and a first dynamic pressure generating groove adjacent to the bent portion. The connection type dynamic pressure generating device according to claim 1, further comprising: a connection groove for connecting to another bent portion, wherein the first and second grooves each form an acute angle with respect to the connection groove. . 3. The connection type dynamic pressure generator according to claim 2, wherein said acute angle is 30 °. 4. The connection type dynamic pressure generating device according to claim 2, wherein said connection grooves are connected continuously along a circumferential direction of said rotary shaft. 5. A fixed shaft, a cylindrical thrust bearing inserted into and fixed to the fixed shaft and having a plurality of dynamic pressure generating grooves formed in a cross section, facing the cross section at a predetermined interval, and facing the fixed shaft. And a drum rotatably inserted and having a signal reading head mounted thereon, wherein the dynamic pressure generating grooves are interconnected to disperse the head fluid pressure. 6. The dynamic pressure generating groove includes a first groove, a second groove connected to the first groove at a bent portion, and another of the first dynamic pressure generating groove adjacent to the bent portion. The connection type dynamic pressure generator according to claim 5, further comprising a connection groove connecting the bent portion, wherein the first and second grooves each form an acute angle with respect to the connection groove. 7. A dynamic pressure generating device according to claim 6, wherein said acute angle is 30 °. 8. The dynamic pressure generating device according to claim 6, wherein said connecting grooves are continuously connected along a circumferential direction of said cross section.