First Traction Results of High Spinning Large-Size Circular EHD Contacts from a New Test Rig: Tribogyr

Abstract

This article presents a new test rig named Tribogyr and the first results obtained so far. This device allows EHL friction tests in rolling-sliding under high spinning conditions applied to large-size circular contacts. Spinning is imposed thanks to a unique design that includes a tilting facility of one of the two spindles. After a brief description of the test rig structure and of the specimen geometry, the sensor's implementation and the device capabilities are reported. The parameter used to quantify the spin in this study is then defined. It only takes into account the rotational speed normal to the contact surface and the contact radius. Then, the friction coefficient and the temperature measurements are presented. The data are at first plotted versus the classical slide-to-roll ratio and compared to numerical results obtained with and without spin. The spin parameter then is introduced to replace the slide-to-roll ratio as the varying parameter. This representation allows reporting all the results in the same figure, where the influence of the operating conditions like the entrainment speed, the tilting angle, and the slide-to-roll ratio on friction and on temperature is much more visible. It is discussed that the observed temperature difference increase is generated by an additional shearing introduced by spinning despite an observed reduction of friction.