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A simulation study of rotating impact within a damper of torque converter
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on April 14, 2020 by SAE International in United States
In a torque converter's damper, connected between an engine and transmission, it is very common that both angular velocities are generally not identical, because of the flexible elements. When the angular velocity of either engine output or transmission input abruptly changes, for example, as the result of driving conditions, an internal impact could occur between what is a primary member connected to the engine and secondary member connected to the transmission. From dynamics’ viewpoint, the impact loads are nothing but a response to huge inertial moment as the result of rapid acceleration or deceleration of rotating members involved. Depending on the duration of impact, it could lead to such a large internal moment that its magnitude could be several times the torque an engine’s combustion force can generate. Consequently, the impact load can be very devastating to a torque converter and other power-train members. This work presents a comprehensive and interesting study about the importance of understanding the rotational impact behavior. Using an explicit FEA solver for case studies, it will demonstrate that a clutch placed in the drive system between a flywheel and vibrational damper indeed acts as a torque limiter by cutting off the passage of engine’s inertia load once it reaches its frictional capacity, by the means of clutch slippage. Also contributing to magnitude of the impact load are, obviously, the speed difference between the primary and secondary members, and ratio of rotary inertia between these two. It is interesting to find that the absolute angular velocities of either member involved in the impact may not be so relevant to it.