Hydraulic control system for automatic gearbox has fail safe valves, e.g. for delivering hydraulic pressure from third pressure control valve in third/four gears to clutch or brake

摘要

The system has a change controller, a hydraulic pressure controller with three pressure control valves controlled by magnetic valves, a hydraulic pressure distributor, a lower control valve, a valve for transferring reverse pressure to a brake, two first fail safe valves and an engine braking control change valve. The system has a change controller, a hydraulic pressure controller with three pressure control valves controlled by magnetic valves, a hydraulic pressure distributor, a lower control valve, a valve for transferring reverse pressure to a brake, a first fail safe valve controlled by control pressure to deliver hydraulic pressure from the third pressure control valve in the third and four gears to the second clutch in a drive range and to the second brake in an L range, a second fail safe valve and an engine braking control change valve.