Ntn Corporation

Koya Ohira

Kenji Ito

Masaki Egami

Hidenobu Mikami

Takayuki Kawamura

Takuya Ishii

Yoshinobu Akamatsu

Eiichiro Shimazu

Mari Kataoka

Hidenobu Mikaki

Takashi Yasunishi

An environment-friendly rolling bearing is proposed in which at least one of inner ring, outer ring, rolling elements, seals and retainer is formed of a biodegradable material.

Rolling bearing

Rolling bearings are proposed in which acoustic deterioration is suppressed which maintaining low dust, low torque and long life. Also, a grease for rolling bearings is proposed which is less likely to scatter under centrifugal force at high speed rotation, whereby preventing malfunction and noise of electronic information devices. A lubricating oil film of an ester-series oil having a dynamic viscosity at 40&deg; C. of 35 mm /s or over is formed on the friction surface of a rolling bearing. There is also provided a high-speed rolling bearing in which a lubricating grease having its worked penetration (JIS K2220) adjusted to 175-250 is retained therein. The grease is preferably prepared by adding a thickening agent containing 50 wt % or more of an aliphatic lithium salt 12-24 in carbon number to a base oil comprising 30 wt % or more of an ester oil having a dynamic viscosity at 40&deg; C. of 10 mm /s or over, and having its worked penetration (JIS K2220) adjusted to 175-250.

Rolling bearings and greases for the same

A rolling bearing for use in a dental hand-piece which can withstand sterilizing temperatures ranging from 135-200 .degree. C., and which can be rotated at a speed of 300000 rpm or higher with a minimum amount of lubricant used. This rolling bearing is used in a hand-piece having a shaft to which a dental rotary cutting tool is detachably mounted, a turbine fixed to the shaft, and a passage for introducing compressed air for driving the turbine. The rolling bearing has a retainer formed by sintering a polyimide resin powder so that it has 5-20% by volume of mutually communicating pores and impregnating the sintered member thus formed with a fluorinated oil.

Rolling bearing for a dental instrument hand-piece

A sliding bearing which shows good sliding properties when it is brought into sliding contact with a soft mating member at high temperatures. The sling member is formed from a wear-resistant and heat-resistant resin composition made up of 100 parts by weight of a polyimide resin, and 5-25 parts by weight of scaly graphite.

Heat-resistant sliding bearing

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Mie, Japan

Koya Ohira