DIRECT-COUPLED CLUTCH CONTROLLER FOR HYDRAULIC TRANSMISSION DEVICE

摘要

PURPOSE:To prevent degradation of vibration-resistance or durability due to cavitation by adjusting engagement of clutch through pressure drop regulation at the drain oil path side upon engagement of direct-coupled clutch. CONSTITUTION:In a lockup control valve 420, a spool 422 will displace downward upon exceeding of solenoid pressure Ps over a setting level. Consequently, an oil path 6 will communicate with an oil path 6B while an oil path 6A will communicate with drain port through a restrictor r1. It will also communicate with a drain oil path 6D communicated with the drain port 47b of lockup control valve 470 having function as a relief valve. Consequently, the hydraulic pressure at the clutching sideface of clutch disc 50 will lower below that at the releasing face 50A side. As a results, the clutch disc 50 will pressure contact against the frictional face 20 to engage the direct-coupled clutch 80 resulting in smooth engagement of direct-coupled clutch.