The Rolling Life of the Rolling Body under the Repeated Load

Abstract

In order to obtain quantitative information in regard to the characteristics of friction in the rolling contact of the rolling body in the main shaft bearing of aircraft engines, the test apparatus was designed on the following basis: (1) that it would afford accurate measurement of the rolling friction torque, (2) that it would afford automatic detection of the lifetime of the rolling by means of an oscillograph, and (3) that it would enable us to impose three kinds of load, static load, pulsating load and partially pulsating load, to the test piece. In the present paper, as the continuation of the previous reports, the life characteristics of the rolling piece under repeated compressive loading was discussed by the use of the test apparatus mentioned above. The following conclusions have been obtained from the present test.
(1) The equipment is satisfactory for performing rolling fatigue tests under repeated compressive loading, especially so for automatic detection of the lifetime of the rolling body in the range of measurement by means of a strain-meter.
(2) The value of the torque measured under repeated compressive load is nearly the same as that obtained under static compressive load which is equal to mean the load in the dynamic loading.
(3) The lifetime curve of the rolling piece under repeated compressive load is closed to that under static compressive load in the common basis of the mean load.