Influence Study Of The Cushion Spring On The Dry Double Clutch Torque Transmissibility Characteristic

Dry frictional driven plate is often used for torque transmissibility inboth AMT（Automated Manual Transmission）and DDCT（Dry DoubleClutch Transmission）.In the phase of vehicle starting and gear shifting, itis usually equipped with the cushion spring to minimize the jerk during theclutch engagement and transmit a progressive torque through its axialstiffness. The cushion spring with axial elastic property, stronglyinfluences the clutch torque transmission from the engine to the drivelinethrough its load–deflection characteristic curve. Therefore, knowledge ofthe cushion spring compression behavior is crucial to improve the clutchengagement performance and shift quality.In this paper, based on detailed analysis of the dry-clutch driven platestructure and its torque transmissibility characteristic, the3D and finiteelement model of cushion spring have been proposed. An FE analysis wasperformed to simulate its compression process and investigate how thecushion spring nonlinear load–deflection curve depends on the temperature,using the above-mentioned ABAQUS model. Also, some results areachieved about the relationship between cushion spring load andtemperature under different compression levels. Finally, the simulationresults are compared with experimental data, and the correctness of modeland simulation results have been verifiedTo further study the relationship between nonlinear load-deflectioncharacteristic of the cushion spring and the clutch torque transmissibility,as well as the effect of the former variation on the latter, a dry clutchtorque transmission model is proposed, based on detailed analysis of the dry clutch torque transmitting process. Then, the torque transmissibilitycharacteristics were analyzed under different condition changes, such astemperature, the friction facing wear and the structural parameters ofcushion spring. The results show that there is a very close relationshipbetween clutch torque transmissibility and the cushion springload-deflection characteristic. As a consequence of temperature rise andincreased wear, the torque transmissibility characteristic appears todegrade, which may cause the jerk and affect comfort during the clutchengagement.The results of this paper can provide a theoretical basis for torquetransmissibility precise control in the dry dual clutch engagement process,which also have important practical value for vehicle startup and gear shiftperformance improvement. Besides, it provides useful experience infurther design and structure optimization of dry dual clutch.