Hydraulic valve assembly

摘要

A hydraulic valve assembly comprises a valve body defining first and second valve receptacle bores, a fluid pump, a first fluid passage communicated with the fluid pump, a second fluid passage communicated with a hydraulic load, and a third fluid passage communicated with a fluid reservoir. A first valve sub-assembly including a sleeve enclosing a first valve mechanism therein is disposed within the first valve receptacle body for selectively permitting and blocking introduction of the pressurized working fluid. Also, a second valve sub-assembly including a sleeve enclosing a second valve mechanism therein is disposed within the second valve receptacle bore for selectively establishing and blocking fluid communication between the second and third fluid passage means. A third valve assembly is provided in the valve body for selectively establishing and blocking fluid communication between the load side of the first valve sub-assembly and the second fluid passage for supplying the pressurized working fluid to the hydraulic load. A control valve assembly is provided in the valve body for generating a control pressure for controlling position of the first and second valve subassemblies.