HYDRAULISK DREJEGLIDERVENTIL FOR SERVOMOTORSYSTEMER,ISAER STYRESYSTEMER

摘要

The invention relates to a control valve assembly for a hydrostatic control system such as a power steering assembly. A common control valve assembly of this type has relatively rotatable inner and outer elements connected respectively to a vehicle steering wheel and a servomotor. Paired holes in the inner and outer elements permit the flow of fluid therethrough when the unit is in its neutral position with the paired holes in respective registration. In prior art units disturbing vibrations occur during the transition from the neutral position to a working position when the paired holes are moved out of registration. These vibrations are eliminated by making the holes in the outer element of varying size and larger than the corresponding holes in the inner element so that a gradual or progressive reduction of the porting area takes place instead of the paired holes closing simultaneously. Also, a chamber having a flow restricting orifice is incorporated downstream from the holes of the inner element. This provides a sound absorbing system by means of which disturbing noises can be greatly reduced.