Patent ID: 7422033

Claim:
In a valve assembly having body in which a control spool selectively controls flow of fluid between at least one workport and both a supply passage and a return passage, a pilot valve comprising: a piston bore formed in the body; a pilot piston connected to the control spool and slideably received in the piston bore, thereby defining a first chamber and a second chamber in the piston bore, wherein the pilot piston is tubular and extends around the control spool; a pilot spool slidably received in the body and moveable into first and second positions with respect to the control spool, wherein in the first position the first chamber communicates with the supply passage but not with the tank passage and the second chamber communicates with the tank passage, and in the second position the second chamber communicates with the supply passage but not with the tank passage, wherein the pilot spool is slidably received within a bore in the control spool and wherein the pilot spool has passages therein which form the fluid paths between each of the first chamber and a second chamber and the supply passage and a return passage in selected positions of the pilot spool; and a linear actuator engaging the pilot spool to move the pilot spool with respect to the control spool.