Matsushita Electric Industrial Co., Ltd.

Yasunori Tokunou

Takafumi Asada

Hideaki Ohno

Tsutomu Hamada

Toshikazu Shogase

Makoto Sunouchi

Kouichi Inoue

Takeshi Yoshikawa

A hydrodynamic bearing device capable of inhibiting leakage of a working fluid to an outside of a bearing and preventing reduction in radial bearing rigidity, and capable of keeping a gap between a thrust bearing and a radial bearing favorable and rotating stably. The hydrodynamic bearing device includes a shaft relatively rotatably inserted into a bearing hole of a sleeve, a radial bearing surface having dynamic pressure generating grooves formed on at least one of an outer peripheral surface of the shaft and an inner peripheral surface of the sleeve, and a gap filled with a working fluid between the shaft and the sleeve. The shaft is made of high manganese chrome steel or stainless steel, and the sleeve is entirely made of sintered metal of metal particles including at least 60% by weight of iron or copper. Resin, metal or water glass is impregnated in pores on a surface of the sintered metal and cured. Thereby, leakage of the working fluid to the outside of the bearing from the sleeve can be inhibited, and reduction in the pressure inside the bearing can be prevented.

Hydrodynamic bearing device

A manufacturing method is provided for forming a hollow cylinder with a bottom which may be employed in rotary head drums of magnetic recording and reproduction systems such as video tape recorders and digital audio tape recorders. The manufacturing method includes pressing a single circular plate to form the hollow cylinder, thrusting an end of a side wall of the hollow cylinder in a direction substantially parallel to the side wall in a press die so as to adjust the thickness of the side wall to be uniform, and machining an outer surface of the side wall of the hollow cylinder so as to have a given surface roughness and a given roundness.

Method of manufacturing bottomed hollow cylinder using a press

Growing community of inventors

Saijyou, Japan

Yasunori Tokunou