It is preferable to be able to change the power steering characteristics according to the car running conditions. This article describes a new power steering system which has been developed by Toyota, which enables the steering characteristics of the car to be adjusted according to vehicle running conditions. The characteristics of this power steering system are decided not only by mechanical construction, but also by the composition of the electronic-hydraulic control circuit used. For this reason, simulation calculation and experiments were used for the evaluation and selection of the hydraulic control circuit, and the characteristics thus obtained were confirmed. This simulation was used right from the start of engine development, the inspection and adjustment methods for the actual production were decided, and maintaining of the quality was planned. Some of production technology used for the electric-hydraulic control valve used for this system, is also presented.
Abstract