Abstract
The improvement of fuel consumption and the exhaust gas regulations, both in regard to automobiles, are becoming increasingly a world wide essential issue from the viewpoint of a global ecological problem. In addition, in response to a request for easy driving of automobiles, power steering systems providing a lighter steering effort are being more and more requested to equip automobiles.
Even the power steering systems are not regarded as an exception to the energy saving movement. Then, electric driven power steering system as described hereby is considered to be so effective that it can make a direct use of electric energy supplied by battery in order to provide a power assistance only at need. It is represented by an electric pump type hydraulic power steering system and an electric power steering system, both considered as optimal for energy saving.