DREHSCHIEBER.

摘要

A core for a rotary valve for a power steering system having in its periphery a plurality of blind ended longitudinally extending slots separated by lands for use in a sleeve member having in its bore a similar array of longitudinally extending blind ended slots matching those of the valve core but in an underlap relationship thereto, the slots of one being wider than the lands of the other so defining a set of longitudinally extending orifices which open and close when relative rotation in either direction from a neutral position occurs between the valve core and the sleeve in which at least two sets of valve core edges have along a substantial portion of their length a contour which extends substantially parallel to the core axis characterised in that the contour comprises in section a continuous curve wherein, at points near the high operating pressure zone thereof, it has a large radius of curvature and lies substantially parallel to the valve core periphery and wherein at a point along the curve approaching the coacting edge of an adjacent sleeve land edge when in the neutral position of the valve it lies at a steep slope to the valve core periphery with a curve of progressively smaller radius therebetween.