ISO 28580:2018 乗用車、トラック、バスタイヤの転がり抵抗測定法—一点試験と測定結果の相関 | ページ 5

3.1

rolling resistance

F_r

loss of energy (or energy consumed) per unit of distance travelled

Note 1 to entry: The SI unit conventionally used for the rolling resistance is the newton metre per metre (N m/m). This is equivalent to a drag force in newtons (N).

3.2

rolling resistance coefficient

C_r

ratio of the rolling resistance to the load on the tyre

Note 1 to entry: Rolling resistance is measured in newtons (N).

Note 2 to entry: Load on the tyre is measured in kilonewtons (kN).

Note 3 to entry: Although this quantity is dimensionless, it is conventionally expressed in N/kN.

3.3

capped inflation

process of inflating the tyre to the required cold pressure and allowing the inflation pressure to build up as the tyre is warmed up while running

3.4

parasitic loss

loss of energy (or energy consumed) per unit distance excluding internal tyre losses, and attributable to aerodynamic loss of the different rotating elements of the test equipment, bearing friction and other sources of systematic loss which can be inherent in the measurement

Note 1 to entry: This document describes which of them are to be excluded from the result of the measurement.

3.5

skim test reading

type of parasitic loss measurement, in which the tyre is kept rolling, without slippage, while reducing the tyre load to a level at which energy loss within the tyre itself is virtually zero

3.6

moment of inertia

inertia

ratio of the torque applied to a rotating body, such as a tyre assembly or machine drum, to the rotational acceleration of this body

Note 1 to entry: See Annex B.

3.7

new test tyre

tyre which has not been previously used in a rolling deflected test which elevates the tyre’s temperature to higher than that generated in rolling resistance tests or has not been exposed to a temperature higher than 40 °C

Note 1 to entry: Repetition of allowed test procedures is permitted.

Note 2 to entry: See examples in this document, ISO 18164, SAE J1269, SAE J2452.

3.8

correlation of measurement results

computations on a set of rolling resistance measurements to be carried out on a regular time basis by separate laboratories in order to allow direct comparisons between their rolling resistance results

Note 1 to entry: The results of these measurements are used to compute"alignment" corrective coefficients and permit calculation of aligned rolling resistance measurement, C_{r aligned} (see Clause 10).

3.9

reference machine

any machine considered as a reference for an alignment

Note 1 to entry: Every tyre testing spindle in one specific measurement method is considered a machine for the purposes of this standard. For example, two spindles acting on the same drum shall not be considered as one machine. One spindle able to measure tyre rolling resistance through different methods shall not be considered as one machine.

3.9.1

physical reference machine

machine (and its corresponding laboratory quality systems) used to set alignment values

3.9.2

virtual reference machine

several machines (and their corresponding laboratory quality systems) used to set alignment values

3.10

candidate machine

machine intended to measure new test tyres, with alignment to a reference machine, according to this document

3.11

alignment tyres

set of tyres measured by both the candidate and reference machines to perform machine alignment

3.12

laboratory control tyre

tyre used by an individual laboratory to control machine behaviour, e.g. machine drift, as a function of time

3.13

measurement repeatability

σ_m

dispersion of the results obtained on one machine for different measurements performed on the same tyre(s) over a short period of time under the same testing conditions

3.14

machine drift

change in the measured value over time which can be attributed to systematic (or progressive) sources of variation

3.15

passenger car tyre

tyre of a group intended for application on 4-wheeled vehicles designed primarily for carrying fewer than 10 persons

Note 1 to entry: See Annex D for a list of standards which identify this tyre type.

3.16

truck and bus tyre

tyre of a group intended for application on vehicles designed primarily for the transportation of property or for carrying more than 10 persons

Note 1 to entry: Such tyres are normally primarily designed for use on light trucks, trucks, buses and their trailers and include those tyres marked with “LT”, “C”, “ST”, “CP”.

Note 2 to entry: See Annex D for a list of standards which identify this tyre type.

3.16.1

smaller truck and bus tyre

truck and bus tyre with a load index of 121 and smaller or ここで, the load index is not marked, a maximum load of 1 450 kg and lower

3.16.2

larger truck and bus tyre

truck and bus tyre with a load index greater than 121 or ここで, the load index is not marked, a maximum load of more than 1 450 kg