Automotive dry clutch fully coupled transient tribodynamics

I Minas,M O’Mahony,J Voveris,S Theodossiades,N Morris

doi:10.1007/s11071-021-06605-x

I Minas, M O’Mahony + Show 3 more

Open Access

https://doi.org/10.1007/s11071-021-06605-x

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Abstract

Determining the root causes of Noise, Vibration and Harshness (NVH) phenomena in modern automotive drivetrains is a task of critical importance. This research investigates the stability of dry clutch systems vibrational behaviour during engagement. A fully coupled dry clutch numerical model including the influence of friction is presented and validated using vehicle measurements. The clutch component frictional properties are measured using parts that exhibit aggressive NVH behaviour using representative tribometric experiments. The validated numerical tool highlights the occurrence of instabilities which are caused by modal couplings, particularly between the input shaft bending and clutch disc radial motions. Such a validated transient dynamics model of a dry clutch system has not hitherto been presented in the open literature.

Highlights

Friction-induced oscillations can cause a variety of issues in automotive powertrains with most prominent manifestations being aggressive Noise, Vibration and Harshness (NVH) concerns, such as chatter and squeal
The methodology expounded in this research employs a transient dynamics model using lumped parameters to predict the oscillatory behaviour of the clutch components
The relative angular velocities of the flywheel and input shaft are shown, where time zero corresponds to the first contact of the pressure plate and flywheel to the clutch disc, referred to as the ‘kiss point’ [43]. At this instant it is assumed there is a nominal cushion spring load of 70 N and as a result friction torque is generated between the clutch components

Summary

Introduction

Friction-induced oscillations can cause a variety of issues in automotive powertrains with most prominent manifestations being aggressive Noise, Vibration and Harshness (NVH) concerns, such as chatter and squeal. Two subsystems prone to NVH issues are the vehicle braking system and the dry clutch system. The two predominant mechanisms that cause instabilities in such systems are frictional stick slip [4] and modal-coupling [5]. Low frequency NVH such as judder (5–20 Hz), has been shown to result from frictional stick slip behaviour [6,7,8,9,10], whereas the majority of high frequency instabilities have been shown to occur due to mode coupling [11,12,13,14]

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