Steuerungssysteme für die Überbrückungskupplung eines Momentwandlers

摘要

A lockup control system for torque converter (12) is provided with an electromagnetic valve (11) and a spool valve (13). When the electromagnetic valve (11) is inactive, the spool valve (13) is set so that a pressure at an OFF port (171) of a torque converter (12) is higher than that of an ON port (172), thereby releasing a lockup clutch (19). When the electromagnetic valve (11) is activated, its control pressure (Pc) becomes lower than a secondary pressure (PL2) and the spool valve (13) is actuated so that the control pressure (Pc) is supplied to a clutch control chamber (18). As a result, the lockup clutch (19) is engaged. At this time, the control pressure (Pc) acts directly in the clutch control oil chamber (18) so that the lockup clutch (19) is controlled with high precision. $$