Ngk Spark Plug Company, Limited

Niterra Co., Ltd.

Atsutoshi Sugiyama

Hironobu Ishikawa

Yusuke Makino

Tetsuji Yogo

Naoya Nakanishi

Yuya Higashide

Hidefumi Suzuki

Kaoru Osaki

An object of the present invention is to suppress adhesion of scale to a surface of a ceramic heater that is used for fluid heating. The ceramic heater has a ceramic body and a coating layer. The ceramic body has a heat generation resistor. The coating layer contains glass as a main component and is formed so as to coat a surface of the ceramic body. The coating layer has a function of smoothing the surface of the ceramic body.

Ceramic heater

A ceramic dynamic-pressure bearing includes a first memberhaving a cylindrical outer surface and a second memberhaving a cylindrical reception hole formed therein. The first memberis inserted into the reception hole. A radial dynamic-pressure gap is formed between the inner surface of the reception hole of the second memberand the outer circumferential surface of the first memberThe first memberand the second memberare formed of an alumina ceramic which contains an Al component in an amount of 90&#x2013;99.5% by mass as reduced to AlOand an oxide-type sintering aid component in an amount of 0.5&#x2013;10% by mass as reduced to an oxide thereof. The thrust dynamic-pressure gap definition surface of the second member which faces the thrust plate has a flatness of not greater than 3 &#x3bc;m or the thrust dynamic-pressure gap definition surface of the thrust plate which faces the second member has a flatness of not greater than 3 &#x3bc;m. Also disclosed is a hard disk drive having a motor including a motor rotation output section having the ceramic dynamic-pressure bearing.

Ceramic dynamic-pressure bearing and hard disk drive using the same

A ceramic dynamic pressure bearing, includes: a first member having an outer periphery formed with a gap forming surface causing a radial dynamic pressure, and a second member having an inner periphery defining a through hole formed with a gap forming surface causing the radial dynamic pressure. The first member is inserted into the through hole as to form a radial gap. The first member and the second member make rotation relative to each other to cause a fluid dynamic pressure at the radial gap. The first member and the second member are composed of an alumina ceramic including: an aluminum 90% to 99.5% by weight, and an oxide sintering assistant 0.5% to 10% by weight. The outer periphery has cylindricity not larger than 1.0 &mgr;m, and roundness not larger than 0.5 &mgr;m. The inner periphery has cylindricity not larger than 1.5 &mgr;m, and roundness not larger than 1.0 &mgr;m.

Ceramic dynamic pressure bearing, motor with bearing, hard disk device, and polygon scanner

Growing community of inventors

Gifu, Japan

Atsutoshi Sugiyama