Technical Trends Regarding Electric Components for Electric Power Steering Systems

Koyo became the first in the world to succeed in commercializing an electric power steering (hereafter "EPS") system in 1988 for installation on a subcompact vehicle, a column-assist type (hereafter "C-EPS") having a DC motordriven power assist unit integrated onto a steering column. Since then, this type of EPS system has been expanding market share in Japan, especially in regard to subcompact vehicles. In Europe also, needs for installation of power steering systems have come to cover even compact vehicles as a rate of the installation has been more and more increasing. Then, since 1996, EPS system has been mounted mainly on the compact vehicles difficult to equip with hydraulic power steering systems. Initially EPS system was needed as a power steering system principally for vehicles not only in favor of energy saving but also difficult to equip with hydraulic power steering system, while from now on the system would evolve into the more safe and comfortable one in the face of increasing needs for additional functions inherently available in EPS system. The following are descriptions about the technological trend and future of EPS system's components, particularly its electric components.