Electro-hydraulic valve for proportional control of spring apply hydraulic release (SAHR) brakes

An electro-hydraulic valve assembly comprising:

• a relay valve having a floating valve spool movable between a first valve position, a second valve position, and a center valve position using hydraulic actuation and spring return, the relay valve defining a tank port, a working port, a pressure supply port, the relay valve having first actuators configured to act on a first end of the floating valve spool and second actuators configured to act on an opposite second end of the floating valve spool;
• wherein one of the second actuators is configured to receive hydraulic pressure from a pilot valve;
• wherein in the first valve position, the pressure supply port communicates with the working port and the tank port is closed;
• wherein in the second valve position, the pressure supply port is closed and the pressure supply port communicates via a first sense line with one of the first actuators, the working port directs pressure to the tank port, the tank port communicates via a second sense line with another of the first actuators, and the working port communicates via a third sense line with one of the second actuators;
• and
• wherein in the center position, the tank port, the working port, and the pressure supply port are closed.