Combination of new design features on valve piston and valve spring in the Valve subassembly to reduce wear in the valve subassembly

摘要

In a particular valve body, valve subassembly 1 consists of valve piston 3, coil spring 4 and retainer 5 assembled in valve body bore 2. When fluid channels are pressurized in the system. Valve piston performs oscillating movements in the bore which effects closing or opening of relevant connected channels. This oscillating motion causes severe wear in valve bore affecting valve functionality. Present invention provides solution to reduce frictional interaction between valve and bore significantly. The idea is to add four design features together on valve and valve spring that minimize severity of radial contacts between them. Hourglass shaped coil spring 4 with diametrically smaller mid coils, even under compressed state, does not contact bore ID surface. Spring radial displacements do not reach bore surface. Spherical end 7 of valve provides axial reaction to load making axis centered contact with valve body drafted face 6 (1° draft) avoiding the moment that is created with flat face 10 of valve. Relocating oil grooves 8 away from the bore edges avoids edge to edge interaction and clearly eliminates edge ramming into the bore edge. Valve piston stem as conical shape 9 with diameter equal to coil spring ID keeps spring centered and does not allow spring to offset in the bore.