ISO 281:2007 転がり軸受—動的定格荷重と定格寿命 | ページ 6

3.1

life

number of revolutions which one of the bearing rings or washers makes in relation to the other ring or washer before the first evidence of fatigue develops in the material of one of the rings or washers or one of the rolling elements

Note 1 to entry: Life may also be expressed in number of hours of operation at a given constant speed of rotation.

3.2

reliability

for a group of apparently identical rolling bearings, operating under the same conditions, the percentage of the group that is expected to attain or exceed a specified life

Note 1 to entry: The reliability of an individual rolling bearing is the probability that the bearing will attain or exceed a specified life.

3.3

rating life

predicted value of life based on a basic dynamic radial load rating or a basic dynamic axial load rating

3.4

basic rating life

rating life associated with 90 % reliability for bearings manufactured with commonly used high quality material, of good manufacturing quality, and operating under conventional operating conditions

3.5

modified rating life

rating life modified for 90 % or other reliability, bearing fatigue load, and/or special bearing properties, and/or contaminated lubricant, and/or other non-conventional operating conditions

Note 1 to entry: The term “modified rating life” is new in this document and replaces “adjusted rating life”.

3.6

basic dynamic radial load rating

constant stationary radial load which a rolling bearing can theoretically endure for a basic rating life of one million revolutions

Note 1 to entry: In the case of a single-row angular contact bearing, the radial load rating refers to the radial component of that load which causes a purely radial displacement of the bearing rings in relation to each other.

3.7

basic dynamic axial load rating

constant centric axial load which a rolling bearing can theoretically endure for a basic rating life of one million revolutions

3.8

dynamic equivalent radial load

constant stationary radial load under the influence of which a rolling bearing would have the same life as it would attain under the actual load conditions

3.9

dynamic equivalent axial load

constant centric axial load under the influence of which a rolling bearing would have the same life as it would attain under the actual load conditions

3.10

fatigue load limit

bearing load under which the fatigue stress limit, σ_u, is just reached in the most heavily loaded raceway contact

3.11

roller diameter

theoretical diameter in a radial plane through the middle of the roller length for a symmetrical roller

Note 1 to entry: For a tapered roller, the applicable diameter is equal to the mean value of the diameters at the imaginary sharp corners at the large end and at the small end of the roller.

Note 2 to entry: For an asymmetrical convex roller, the applicable diameter is an approximation of the diameter at the point of contact between the roller and the ribless raceway at zero load.

3.12

effective roller length

theoretical maximum length of contact between a roller and that raceway where the contact is shortest

Note 1 to entry: This is normally taken to be either the distance between the theoretically sharp corners of the roller minus the roller chamfers or the raceway width, excluding the grinding undercuts, whichever is the smaller.

3.13

nominal contact angle

angle between a plane perpendicular to a bearing axis (a radial plane) and the nominal line of action of the resultant of the forces transmitted by a bearing ring or washer to a rolling element

Note 1 to entry: For bearings with asymmetrical rollers, the nominal contact angle is determined by the contact with the non-ribbed raceway.

3.14

pitch diameter of ball set

diameter of the circle containing the centres of the balls in one row in a bearing

3.15

pitch diameter of roller set

diameter of the circle intersecting the roller axes at the middle of the rollers in one row in a bearing

3.16

conventional operating conditions

conditions which may be assumed to prevail for a bearing which is properly mounted and protected from foreign matter, adequately lubricated, conventionally loaded, not exposed to extreme temperature and not run at exceptionally low or high speed

3.17

viscosity ratio

actual kinematic oil viscosity at operating temperature divided by the reference kinematic viscosity for adequate lubrication

3.18

film parameter

ratio of lubricant film thickness to composite r.m.s. surface roughness, used to estimate the influence of lubrication on bearing life

3.19

pressure-viscosity coefficient

parameter characterizing the influence of oil pressure on the oil viscosity in the rolling element contact

3.20

viscosity index

index characterizing the degree of influence of temperature on the viscosity of lubricating oils