Nsk Corporation

Hideyuki Uyama

Tomohiro Motoda

Nobuaki Mitamura

Koji Ueda

Shigeru Okita

Susumu Tanaka

Tsuyoshi Saito

Shinji Fujita

Yuuji Miyamoto

Yohei Murata

Atsushi Imai

Hiroki Yamada

Provided are a method for assessing hydrogen environment severity of a rolling device during operation and a method for predicting likelihood that white structure damage occurs to the rolling device as a result of operation. A hydrogen environment severity assessment method is a method for assessing, among operating conditions of a rolling device including two rolling members coming into rolling contact with each other and having at least one of the two rolling members being a steel rolling member, hydrogen environment severity, the hydrogen environment severity being an index representing magnitude of influence exerted by hydrogen. The hydrogen environment severity assessment method includes a measurement step of measuring the amount of room temperature non-diffusible hydrogen contained in a rolling fatigue region, the rolling fatigue region being a region where rolling fatigue has been produced by rolling contact, within the steel rolling member of the rolling device operated under the operating conditions and an assessment step of assessing the hydrogen environment severity, based on a measurement result in the measurement step.

Ambient-hydrogen-level assessment method and white-structure-damage-likelihood prediction method

Provided is a friction design method capable of estimating sliding friction generated between mutual sliding surfaces of two sliding members lubricated with lubricant with high precision. The friction design method sets a friction coefficient &#x3bc; in a sliding surface model corresponding to mutual sliding surfaces of two sliding members (and) lubricated with lubricant (step S), and, based on a correlation between the friction coefficient &#x3bc; and an oil film parameter (&#x39b;(Rk) or &#x39b;(Rk+Rpk)) calculated using a core portion level difference (Rk) or a sum of the core portion level difference (Rk) and reduced peak height (Rpk) as a parameter representing surface roughness in the sliding surface model (step S), sets a target value for surface roughness of the sliding surfaces required to be controlled as a product (steps Sto S).

Friction design method and surface roughness control method for sliding member and production method for sliding mechanism

A rolling bearing has an outer diameter surface of the outer ring which is a fitting surface with a housing and the inner diameter surface of the inner ring, which is a fitting surface with a shaft. The outer diameter surface of the outer ring or the inner diameter surface of the inner ring is coated with a bonded film containing an organic binder, a solid lubricant powder such as molybdenum disulfide powder, and a friction/wear modifier such as antimony oxide powder. According to the rolling bearing, a creep resistance is kept excellent without causing increase in cost and size and being deformed and softened.

Rolling bearing and production process therefor

In a wheel-support rolling bearing unit, in order to made a flangethinner and thus lighten the bearing unit without impairing fatigue strength, machinability, and workability after forging, the composition of the alloy steel constituting the flange attached member (hub ring), the surface hardness of the root portionon the axial outside surface side of the flange, and the surface roughness, are stipulated to thereby improve the durability ratio (fatigue limit strength/tensile strength) of the flange. In one aspect, the member is made from an alloy steel containing C: 0.5 to 0.65 weight %, Mn: 0.3 to 1.5 weight %, Si: 0.1 to 1.0 weight %, Cr: 0.01 to 0.5 weight %, S: 0.35 weight % or less, and any one type or more selected from 0.01 to 0.2 weight % of V, 0.01 to 0.15 weight % of Nb, and 0.01 to 0.15 weight % of Ti, with the rest being Fe and inevitable impurities, and the oxygen contents is 15 ppm or less. Moreover, the surface hardness of the inner racewayformed with the hardened layer, is between Hv 650 and 780, and the surface hardness of a portion not formed with the hardened layer is between Hv 230 and 300.

Wheel-support rolling bearing unit

A rolling bearing has the radius of curvature of the raceway on an inner ring and an outer ring is from not smaller than 50.1% to not greater than 51.9% of the diameter of the balls, and at least one of the compositions of the bearing is obtained by forming an alloy steel having a carbon (C) content of from not smaller than 0.50% to not greater than 0.90%, a chromium (Cr) content of from not smaller than 3.0% to not greater than 15.0%, a manganese (Mn) content of from not smaller than 0.10% to not greater than 2.0%, a silicon (Si) content of from not smaller than 0.10% to not greater than 2.0%, a molybdenum (Mo) content of zero or not greater than 2.0% by weight, and a vanadium (V) content of zero or not greater than 2.0%, by weight.

Rolling bearing and belt continuously variable transmission

The bearing rings and of a rolling bearing is formed of one kind of titanium alloys of &bgr; type titanium alloys, near &bgr; type titanium alloys and &agr;&plus;&bgr; type titanium alloys. The titanium alloy has a surface hardness of Hv 400 or more and less than Hv 600 for increasing the corrosion resistance and wear resistance of the bearing ring. Spherical rolling elements rolling on the raceway surfaces and of the bearing rings and are formed of ceramics such as silicon nitride. When &bgr; type titanium alloys or &agr;&plus;&bgr; type titanium alloys after a solution treatment and applied with an oxidation treatment at a low temperature of 400 to 600&deg; C. are used as the material for the bearing ring, a bearing ring made of titanium alloy suitable to use under a circumstance requiring corrosion resistance is obtained.

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Fujisawa, Japan

Hideyuki Uyama