Abstract
We have developed a instrument for measuring frictional coefficient on wheels, which is called "μ-tester." The measurement procedure of the μ-tester is as follows; 1) Its roller is contacted to a measuring plane by a spring. 2) The roller is slide rotated on the measuring plane by pulling a string twisted around the boss of the roller. 3) The value of frictional coefficient is calculated from the pulling force and the normal load, which are sensed by load cells. The μ-tester can measure various surfaces such as a rail and a roller rig in addition to a wheel by exchanging a fixture. The values of frictional coefficient of a rail measured by the μ-tester were generally in agreement with that measured by a rail tribometer.
