A two-position, two-stage servo valve includes a valve body, a valve element, a control pressure chamber, and a control element. The valve body has an inner surface that defines a valve element chamber that includes a first control chamber and a second control chamber. The first control chamber is larger than the second control chamber. The valve element has first and second ends and is disposed within the valve element chamber and is movable between a first valve position and a second valve position. The first end is larger than the second end and is disposed within the first control chamber, and the second end is disposed within the second control chamber. The control pressure chamber includes a control pressure port that is in continuous fluid communication with the first control chamber. The control element is movable between a first control position and a second control position.

A hydraulic suspension system includes a suspension cylinder, a pump, and a control valve therebetween. The control valve includes a spool reciprocally movable between a pump flow position and a tank flow position in which a control port of the control valve is in communication with a pump and a tank, respectively. A piloted logic element in fluid communication with and interposed between the control valve and the suspension cylinder is selectively movable between a through-flow position in which fluid can flow in either direction between a chamber of the suspension cylinder and the control port of the control valve and a blocked position in which fluid is prevented from flowing in or out of the chamber of the suspension cylinder. The logic element is biased to the blocking position, moving to the through-flow position when subjected to a crack pressure delivered from the control port of the control valve.

An oil control valve has a cup shaft and a plunger. The cup shaft and the plunger have a projection and a recess to provide a male-female joint. The male-female joint provides contact points which can reduce lateral offset and inclination. The projection and the recess provides two or more force transmitting points from the plunger to the cup shaft, when the projection and the recess are inclined with each other. The force transmitting points are located about the central axis of the spool in a distributed manner.

A valve for a well system including a valve housing including a first housing port, a second housing port, and a bore, a piston received in the bore and including a first end, a second end, and an annular flange including a first annular surface and a second annular surface both of which are in fluid communication with the second housing port, a piston seal disposed in the outer surface of the piston and in sealing engagement with an inner surface of the bore, and a cage assembly that includes a cage including a bore, a first cage port, a second cage port, and a third cage port, and a spool disposed in the cage and coupled to the piston, the spool including a throughbore.