PROPORTIONAL FOLLOWER SPOOL VALVE SYSTEM

摘要

A proportional follower spool valve system having a main spool slidable between end chambers maintained at substantially return pressure. First fluid connections are controlled by the main spool and they are effective to control output fluid flow in accordance with the position of the main spool. A pilot spool is slidable within an inner passage of the main spool. A first and a second driving chamber is formed by the main spool each having a driving area substantially less than the largest cross-sectional solid area of the main spool. Second fluid connections are controlled by the pilot spool for admitting fluid under pressure (1) to the first chamber when the pilot spool moves in a first direction away from the first chamber and (2) to the second chamber when the pilot spool moves in a second direction away from the second chamber. Each of the first and second driving chambers are disposed between a respective end chamber and a passage for return pressure.