IMPROVED PROPERTIES OF HIGH STRENGTH 18Ni MARAGING STEELS FOR PUSHBELT CVT APPLICATIONS BY OPTIMIZATION OF ALLOY COMPOSITIONS AND SURFACE HARDENING HEAT TREATMENTS

摘要

In recent years the use of pushbelt Continuously Variable Transmissions (CVT) in automotive applications has seen a strong worldwide growth that is foreseen to rise further within the next years. Bosch contributes to this growth by responding to market demands regarding efficiency, NVH, cost, and power density. The latter comprises transmittable power & torque, transmission size, ratio coverage, and durability. In this paper it will be shown that enhanced power density of the pushbelt CVT can be achieved by improving the properties of the 18Ni maraging steel pushbelt loops, via optimization of the alloy compositions and accompanying surface hardening heat treatments.