Patent ID: 6397695
Filing Date: 2002-06-04
Classification: F16H,Y10T

Abstract:
A control apparatus for a hydraulically-operated vehicular transmission having a plurality of hydraulic engaging elements for selectively establishing a plurality of speed transmission trains, said apparatus comprising:a pair of linear solenoid valves; switching means for switching oil passage connections into a state in which an oil pressure in a hydraulic engaging element for an arbitrary speed transmission train and an oil pressure in a hydraulic engaging element for a speed transmission train which is adjacent, as seen in an order of speed, to said arbitrary speed transmission train are controllable by said pair of linear solenoid valves; first control means for speed changing which controls said switching means at a time of speed changing such that an oil pressure in an off-going hydraulic engaging element for a speed transmission train so far established and an oil pressure in an on-coming hydraulic engaging element for a speed transmission train to be established next which is adjacent, as seen in the order of speed, to the speed transmission train so far established, become controllable by said pair of linear solenoid valves, said first control means also controlling said pair of linear solenoid valves such that the oil pressure in said off-going hydraulic engaging element is lowered by one of said pair of linear solenoid valves, said one linear solenoid valve handling said off-going hydraulic engaging element, and that the oil pressure in said on-coming hydraulic engaging element is increased by the other of said pair of linear solenoid valves, said other linear solenoid valve handling the on-coming hydraulic engaging element; an accumulator connected to an oil passage which is in communication with a predetermined first speed transmission train; and second control means for speed changing which controls said switching means, at a time of speed changing from the first speed transmission train to a second speed transmission train which is not adjacent to the first speed transmission train as seen in the order of speed, such a) that the oil passage which is in communication with a hydraulic engaging element for the first speed transmission train is connected to an oil discharge passage, and b) that an oil pressure in a hydraulic engaging element for the second speed transmission train and an oil pressure in a hydraulic engaging element for a third speed transmission train which is adjacent to the second speed transmission train on a side near the first speed transmission train, as seen in the order of speed, are controllable by said pair of linear solenoid valves, said second control means also controlling said pair of linear solenoid valves such c) that the oil pressure in said hydraulic engaging element for the second speed transmission training increased by one of said pair of liner solenoid valves, paid one linear solenoid valve handling said hydraulic engaging element for the second speed transmission train, and d) that the oil pressure in said hydraulic engaging element for the third speed transmission train is kept to a low pressure waiting state by the other of said pair of liner solenoid valves, said other linear solenoid valve handling said hydraulic engaging element for the third speed transmission train, said second control means controlling said pair of linear solenoid valves when the speed change command to the third speed transmission train is issued in the course of speed changing from the first speed transmission train to the second speed transmission train, such e) that the oil pressure in said hydraulic engaging element for the second speed transmission train is decreased by one of said pair of linear solenoid valves, said one linear solenoid valve handling said hydraulic engaging element for the second speed transmission train, and f) that the oil pressure in said hydraulic engaging element for the third speed transmission train is increased by the other of said pair of linear solenoid valves, said other linear solenoid valve handling said hydraulic engaging element for the third speed transmission train.