Effect of teeth micro-geometrical form modification on contact kinematics and efficiency of high performance transmissions. (September 2017)

• Record Type: Journal Article
• Authors: Elisaus, Vishak; Mohammadpour, Mahdi; Theodossiades, Stephanos; Rahnejat, Homer
• Other Names: Ebrahimi Kambiz guest-editor.; Mohammadpour Mahdi guest-editor.
• Is Part Of: Proceedings of the Institution of Mechanical Engineers. Volume 231:Number 3(2017:Sep.)
• Page Start: 538
• Page End: 555
• Publication Date: 2017-09
• Subjects: High performance transmissions -- spur gear -- micro-geometrical form modification -- contact kinematics -- thermo-elastohydrodynamics -- non-Newtonian traction -- friction -- efficiency; Machinery, Dynamics of -- Periodicals; Machine design -- Periodicals; 621.815
• DOI: 10.1177/1464419317710157
• Languages: English
• ISSNs: 1464-4193

Abstract

Light weight, compactness and efficiency are key objectives in high performance vehicular transmission systems, which are subject to large variations in torque and power. Pitch line velocities of up to 52 m/s and teeth pair contact pressures of up to 3 GPa are routinely encountered under race conditions. Contact patch asymmetry due to angular misalignments between input and output shafts leads to the generation of high edge stress discontinuities on gear flanks, inducing fatigue spalling which affects system durability. Crowning is widely used as a palliative measure to mitigate these undesired effects. These problems can be further exacerbated by contact footprint truncation. The paper presents a new approach to modelling the kinematics and contact micro-geometry of meshing conjunctions of involute spur gears with profile and lead modifications. A time-efficient analytical method is presented to accurately determine the contact footprint and kinematics, leading to the solution of highly loaded non-Newtonian mixed thermo-elastohydrodynamic contact under the extreme prevalent conditions of high performance vehicular transmissions. The effect of tooth form modification on contact footprint truncation, contact kinematics and generated frictional power loss is investigated. This approach has not hitherto been reported in literature.