An experimental approach to comparative thermal behavior of rubber and metallic clutch dampers

Abstract

Clutch is one of the most important components in automobile powertrain systems. The torque generated in an engine is transmitted by friction faces of a clutch disc between pressure plate and flywheel. In addition to transmitting engine torque, the clutch disc has the task of preventing torsional engine vibrations from reaching the powertrain. To achieve this task, the clutch disc is fitted with torsional dampers which have metallic compression springs. Another solution is to use rubber springs instead of metallic ones. Recently rubber materials are widely demanded particularly in the automotive industry with the advantages of high damping capability, lightweight and low cost. In a traffic jam condition, numerous engagement and disengagement create incremental thermal load and temperature increase due to slippage between friction faces. The temperature level in the clutch house is expected to affect material properties of damping components assembled inside the clutch disc. In this paper, the rubber and metallic damper springs were investigated experimentally at the expected temperatures and dynamic loads during driving conditions. Thus, the thermal behavior of rubber springs in the clutch system was observed with the novel approach. Damper torque characteristics, cooling rates and loss of stiffness change with time and frequency have been revealed comparatively. Safety factor coefficient selection for damper torque has the major importance at the system in which the stiffness varies within time due to dynamic loads. In conclusion, the clutch disc used with rubber springs needs correct analysis in terms of design. Results show that how to safety actor should be chosen more attentively for clutch disc used with rubber spring on automobiles and related calculations have to be done before the design phase.