Fluid bearing device and disk recording reproducer

Abstract

A sleeve 1 is fixed on a base. Radial dynamic-pressure generating grooves 1 A and 1 B are provided on an inner surface of the sleeve 1 . A thrust plate 4 hermetically seals a lower opening end of the sleeve 1 . A shaft 2 is inserted inside the sleeve 1 , being allowed to revolve. A flange 3 is fixed at the bottom end of the shaft 2 , and its lower surface is placed close to an upper surface of the thrust plate 4 . Thrust dynamic-pressure generating grooves 3 A and 3 B are provided on the surfaces of the flange 3 . Gaps A-H among the sleeve 1 , the shaft 2 , the flange 3 , and the thrust plate 4 are filled with a lubricant 5 . Hollows 1 C- 1 F are provided on the inner surface of the sleeve 1 . The gaps A and C over the thrust dynamic-pressure generating grooves 3 A and 3 B and their vicinities are narrower than the surrounding gaps B and D (A<B, A<D, C<B, and C<D), and the surrounding gaps B and D are narrower than the gap H in the upper opening end of the sleeve 1 and its vicinity (B<H and D<H). The gaps E and G over the radial dynamic-pressure generating grooves and their vicinities are narrower than the surrounding gaps D and F (E<D, E<F, G<D, and G<F), and the surrounding gaps D and F are narrower than the gap H in the upper opening end of the sleeve 1 and its vicinity (D<H and F<H).

Description

technical field [0001] The present invention relates to a fluid bearing device and a disk recording and reproducing device equipped with the device. Background technique [0002] The magnetic disk recording and reproducing apparatus includes a magnetic disk, and performs magnetic or optical data reading and writing to the magnetic disk while rotating the magnetic disk. At present, larger capacity and faster data transfer are required for magnetic disk recording and reproducing devices. Therefore, it is desired to further increase the rotation speed of the magnetic disk and achieve high-precision stabilization. The fluid bearing device is suitable for the shaft part of this high-speed and high-precision rotary drive system. [0003] Fig. 6 is a sectional view showing an example of a conventional fluid bearing device. The upper end portion of the shaft 31 is fixed to the center of the hub 36 . The flange 33 has an annular shape, passes through the lower end of the shaft 31...

AI Technical Summary

Problems solved by technology

Moreover, when the outflow of the oil 42 is too large, the oil 42 cannot completely cover the entire radial dynamic pressure generating groove and the axial dynamic pressure generating groove, which is the so-called oil film rupture phenomenon.

In this case, due to the insufficient effect of the above-mentioned pump, for example, the shaft 31 and the sleeve 32 or the flange 33 and the thrust plate 34 may contact excessively to accelerate wear.

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