Chapter 5 Hydraulic Control Valves 5.2.2 Directional control valves 1.Functions: According to the core motions relative body,a directional control valve in a hydraulic system is usually used to control the oil paths that can be connected,or the oil flow direction that can be changed,which allows the actuator to be started,stopped or the oil flow direction to be shifted. 2.Classification (1)By configuration:rotary,sliding or ball; (2)By ports:two ports,three ports,four ports and so on: (3)By relative operating position of spool in the valve body. There are two,three,and four positions; Homepage List Upwards Downward止 Retu Exit Chapter 5 Hydraulic Control Valves 14 5.2.2 Directional control valves 1. Functions: According to the core motions relative body, a directional control valve in a hydraulic system is usually used to control the oil paths that can be connected, or the oil flow direction that can be changed, which allows the actuator to be started, stopped or the oil flow direction to be shifted. 2. Classification (1) By configuration: rotary, sliding or ball; (2) By ports: two ports, three ports, four ports and so on; (3) By relative operating position of spool in the valve body. There are two, three, and four positions;