Optimization of Washer Design to avoid Fastener stuck in Rear Driveshaft Flanged Assembly

Abstract

Construction of the rear driveshaft flange has recorded multiple incidences of washer binding when M10 bolts are tightened. Most of the binding occurrences happened in the 8¼ turns of the bolt, which was associated with delays, thread damage, compromised safety, and prolonged cycle completion times. This paper presents a washer redesign with a larger center hole, improved tighter tolerance manufacturing, and a better surface finish. The redesign eliminates binding, improves response to assembly tooling, and reduces cycle time—all without additional cost. It was successfully tested with both single and dual spindle drivers, as well as passing torque failure and bolt slip tests. The threaded fasteners’ contact interfaces and their interactions exhibit complex tribology which makes the torque reading during the tightening process highly variable and, at times, contradictory. For screw threads, particularly those that exhibit variable friction during tightening, morphologies have been identified that influence the fastening process tribologically. The tribological context of surface finish and its effect on manufacturing has been a key focus in the study of friction.