Nsk Corporation

Norihiro Aoki

Hiroshi Nishizawa

Koji Takano

Takafumi Yasuhara

Yoichi Imamura

Chikara Matsuzawa

Masaru Kuge

Fusasuke Goto

Toshikazu Yabe

Takahiko Uchiyama

Toshimi Takajo

Hiromitsu Muraki

Takayuki Yatabe

Kenji Okuma

Akira Iwamoto

Norikazu Kitagawa

A martensitic stainless steel containing, by mass %, C: 0.20% to 0.40%, N: 0.1% or less, Mo: 3% or less, and Cr: 12.0% to 16.0%, such that 0.3%&#x2264;C+N&#x2264;0.4% and a PI value (=Cr+3.3Mo+16N) is 18 or more, with the remainder being substantially Fe and unavoidable impurities is quenched from a temperature of 1,030&#xb0; C. to 1,140&#xb0; C. and subjected to a subzero treatment and tempering so as to obtain a prior austenite crystal grain size of a surface layer of 30 &#x3bc;m to 100 &#x3bc;m and a surface hardness of 58 HRc to 62 HRc.

Manufacturing method of mechanical component using martensitic stainless steel, rotating device, rolling bearing and rolling bearing unit

A rolling-bearing unit comprising a pair of bearing assembled such that the tolerance range of the radial clearance or contact angle of the ball bearings is divided into a plurality of divisions, and that a pair of ball bearings is selected from the same division, and that a pre-load, which is set according to the division, is applied to the selected pair of ball bearings as they are installed in the unit.

Rolling bearing unit

In a seal for a rolling bearing, the seal has a molding member formed from a rubber material, the molding member including a lip portion, the molding member having 0.3 to 5.0 MPa of tensile stress at 10% strain and no less than 50% of elongation at break after the rubber material is subjected to an accelerated air aging at 130.degree. C. for 1000 hours. The rubber material includes the nitrile rubber compound containing a raw-material rubber, with respect to 100 weight parts of the raw-material rubber, 0.3 to 5.0 weight parts of an age resistor, and 0.3 to 5.0 weight parts of at least one secondary age resistor. The seal prevents grease enclosed in the rolling bearing from leaking out, the lip portion from being broken, and dust resistance from being lowered even in the case where the rolling bearing is used in a high-temperature environment.

Seal containing age resistors for rolling bearing

A rolling bearing is composed of an outer race having an inner-race raceway on an outer peripheral wall thereof, an outer race having an outer-race raceway on an inner peripheral wall thereof, a plurality of rolling elements interposed for rotation between the outer-race raceway and the inner race, and a lubricant composition filled in a space, which is defined between the inner-race raceway and the outer-race raceway, at a position where the plurality of rolling elements are disposed. The rolling bearing features: (a) at least one of the inner-race and outer-race raceways is made of steel having an oxygen content not higher than 6 ppm; (b) at least a raceway surface of said at least one raceway has been hardened by heat treatment; (c) the lubricant composition comprises as a base oil a synthetic lubricant having a kinematic viscosity of 60-160 cSt at 40.degree. C.; and (d) the lubricant composition further comprises 18-28 wt. % of a thickener which comprises a polyurea compound.

Rolling bearing

A rolling bearing is composed of an outer race, an inner race and rolling elements interposed between the outer race and the inner race. A lubricant composition comprising a polyether lubricant as a base oil is filled in the bearing. Preferably, the polyether lubricant has a kinematic viscosity 90-160 cSt at 40.degree. C.

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Fujisawa, Japan

Norihiro Aoki