Frictional characteristics of needle roller thrust bearings (Part 1) - In the case of single row type bearing

In this paper, details are discussed with the theoretical and experimental investigation concerning frictional torque of needle roller thrust bearings. With a view to examining, first of all, the frictional torque from a theoretical point of view, roller motion of one of the bearings was explained under the condition that the energy loss generated at the portion where the roller came in contact with the raceways becomes the.. mum. Secondly, by making use of the results obtained above, assessment was made with the frictional torque of the thrust bearing of the single-row type. Meanwhile using a various types of the bearings obtained by changing roller diameter, roller effective length, the number of the rollers and pitch circle diameter, experimental investigations were also conducted under a wide range of the thrust loads at several rotational speeds. The results are summarized as follows: (1) The frictional torque of the needle roller thrust bearing of the single-row type obtained from the analysis is proportional to the thrust load, coefficient of sliding friction and roller effective length. (2) The torque of the bearing is not dependent on the rotational speed, the number of the rollers, bearing pitch diameter and roller diameter. (3) The results obtained from the experiment conducted on the single-row type are in agreement qualitatively with the ones brought about from the theoretical analysis.