JP2516992Y2 - Spindle rotation mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a structure of a spindle unit for rotating an optical disk.

"Prior Art" FIGS. 2 (a), (b) and (c) show a schematic configuration diagram of a conventional spindle unit. Conventionally, this part is shown in Fig. 2 (a).
As shown in, two sets of miniature ball bearings were used.
In addition, as a countermeasure against acoustic noise, an encased metal (oil-impregnated metal) is used to make a single metal as shown in FIG. 2 (b) and a double metal as shown in FIG. 2 (c).

[Problems to be Solved by the Invention] However, the above-described spindle using both metals has the following problems.

(A) Since the general tolerance of the metal inner diameter is about 10 μm, the shaft rotates while swinging.

(B) When used on the spindle, in addition to the fact that the surface pressure on the metal can be obtained only by the imbalance of the disc, the linear velocity is slow, especially in compact disc recording and reproducing devices, so lubricating oil should be used. It is difficult to pull in the load area to generate hydraulic pressure. When using metal under such conditions, the operation interval must be made very small, but it is difficult as described in the problem (a).

(C) When configured as an optical disk device, for example, a non-linear operation of the gap between the shaft and the metal with respect to external disturbance is likely to cause skipped sound.

[Means for Solving the Problems] The present invention is directed to a shaft made of magnetic metal, first and second bearings that support the shaft with a metal oil encapsulation at a predetermined interval, and first and second bearings. The spindle rotation mechanism is provided with a magnet that attracts the shaft in a non-contact position facing the shaft in a substantially middle portion of the above.

[Operation] According to the present invention, the shaft is axially supported by the two oil encapsulating metals (oil-containing metal) with a predetermined interval, and the middle portion of the shaft is attracted by the magnet, so that the shaft is pressed to a predetermined position of the oil encapsulating metal. The whirling phenomenon of the shaft during rotation is reduced, and at the same time, the pumping action of the wrapping oil allows the lubricating oil to enter the part where the shaft is pressed against the wrapping metal, and the shaft can be smoothly supported by the hydraulic pressure. Is held in a state of being sucked by and pressed against one bearing surface of the oil-wrapping metal, and smooth rotation can be obtained by hydraulic pressure to prevent minute fluctuations of the rotation axis.

"Embodiment" An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram according to the present invention.

In the figure, a turntable 2 on which a disc 1 is placed
Is rotated by a driving force applied by a stator 4 fixed to a base 3 and a rotor 5 pivotally supported by a shaft 6. The shaft 6 that engages with the rotor 5 is pivotally supported by the two oil envelopment metals 7 and the thrust receiver 8. Then, a permanent magnet 9 having an annular cross section is arranged in the middle of the two oil-wrapping metal 7.

The shaft 6 is generally made of martensitic stainless steel and is attracted by the permanent magnet 9.
Is always pressed against either surface of the oil-wrapping metal 7. It has also been experimentally confirmed that the change in the axial torque due to the surface pressure has almost no effect on the pressing force (about 50 to 300 g) with which the shaft attracted by the permanent magnet 9 is pressed against the oil-wrapping metal 7. . Therefore, the permanent magnet 9 can be arranged roughly because there is no problem with some error in the pressing force.

[Advantage of the Invention] According to the present invention, one bearing for oil-wrapping metal is provided by a simple mechanism in which a shaft is attracted by a magnet, and two bearing oil-wrapping metal bearings are provided on both sides of the magnet with a predetermined gap. The shaft is held in a state in which it is constantly pressed by the magnetic force on the surface, and it is possible to prevent minute rattling due to runout of the shaft.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIGS. 2 (a), (b) and (c) are schematic configuration diagrams showing a conventional example. 1 ... Disc, 2 ... Turntable, 3 ... Base 4 ... Stator, 5 ... Rotor, 6 ... Shaft 7 ... Oil encapsulation metal, 8 ... Thrust receiver, 9 ... Permanent magnet

Claims (1)

(57) [Scope of utility model registration request] 1. A shaft made of magnetic metal and first and second shafts which are axially supported by an oil-wrapping metal at a predetermined distance.
And a magnet for attracting the shaft at a non-contact position facing the shaft in a substantially intermediate portion between the first bearing and the second bearing.