ELECTROHYDRAULIC TYPE CONTROL SYSTEM

摘要

An electrohydraulic control system comprising a spool valve including a valve body (10) having a bore (12). A spool (11) is positioned in the bore for reciprocating movement within the bore. The valve body has an inlet (15a), an outlet (17a) and an exhaust port (16). An electrohydraulic three-way pulse width modulated valve (14) has an inlet (20) communicating with the inlet to the valve body and an outlet communicating with one end of the spool. A spring (5) yieldingly urges the spool toward the pulse width modulated valve. The spool is positioned so that it normally obstructs a path from the inlet to the outlet. Provision is made for preventing undesirable metering flow to exhaust when the valve is in the full on position.