Optical analysis and measurement-based determination of spring behavior in clutch disc damper systems during dynamic operation

摘要

In vehicle drivetrain application, systems for the reduction of non-uniformities are used such as torque converters, dual mass flywheels (DMF) and clutch dampers. In these drivetrain subsystems the characteristics of the internal, technical springs have a significant influence on the rotational frequency response of the whole drive system. When designing new systems, the current state of technology is to investigate the system behavior using simulation methods and sophisticated test benches. [1] However, the internal behavior of the subsystem "coil spring" in heavy duty clutch systems cannot be analyzed appropriately today because the measurement devices are always externally located. This prohibits the validation of the effects resulting from dynamic maneuvers such as internal combustion engine excitation on "coil spring" level. Developing and applying visualization technologies result in major challenges to get visual access to the "coil spring" subsystems which work in a closed and rotating system. For example the interface forces between coil spring and flange of the physical system cannot be evaluated trough conventional instrumentation. Their influences can be estimated only using simulation methods. [2] This paper presents a new approach to visualize single coil spring dynamics and their interactions with the remaining system under highly dynamic torque loading. This is realized using a highly dynamic drivetrain test bench for scaled clutch damper systems, high speed cameras up to 20'000 frames per second and sophisticated simulation tools. Simultaneously, a method for the compensation of inertia torque was developed. This method is applied to estimate the internal forces in the working surface pair between the coil springs and the flanges. As a result, analysis methods are described to determine the characteristics of the subsystem "coil spring" in the overall torsional damper systems for heavy duty application. The objective is to obtain results without the influence of the test bench system with its additional inertia, thus, excluding the systems behavior like phase shift of torque and twist angle in supercritical state. In addition, structural spring phenomena during rotational excitation under centrifugal force influence can be visualized, analyzed and verified with the use of high speed imaging.