초록 ▼

An automatic transmission comprises a forward/reverse selection hydraulic servomechanism 70 which actuates a dog clutch and a plurality of clutches 11, 12, 13, 14 and 15. For this automatic transmission, a control system comprises first.about.fifth on/off solenoid valves 81.about.85 and first.about.

An automatic transmission comprises a forward/reverse selection hydraulic servomechanism 70 which actuates a dog clutch and a plurality of clutches 11, 12, 13, 14 and 15. For this automatic transmission, a control system comprises first.about.fifth on/off solenoid valves 81.about.85 and first.about.third linear solenoid valves 86.about.88. These valves are used to control the supply and drain of a line pressure to and from the forward/reverse selection hydraulic servomechanism 70 and first.about.fifth shift valves 60, 62, 64, 66 and 68 so as to control the actuation thereof for the selective engagement of the clutches. This system, when it detects, by a hydraulic switch 93, a condition that the D range is selected and that the actuation command signals being sent to the solenoid valves correspond to one of the signal combinations which are used for setting the driving modes of the D range, allows the actuation of the solenoid valves by these actuation command signals.

대표청구항 ▼

1. A control system for an automatic transmission comprising a forward/reverse hydraulic servomechanism which switches and selects either a plurality of forward drive power transmission paths or a reverse drive power transmission path, and comprising a plurality of hydraulic clutches for selectively

1. A control system for an automatic transmission comprising a forward/reverse hydraulic servomechanism which switches and selects either a plurality of forward drive power transmission paths or a reverse drive power transmission path, and comprising a plurality of hydraulic clutches for selectively establishing one of said forward drive power transmission paths, each hydraulic clutch being provided for a corresponding one of said forward drive power transmission paths;said control system comprising: a plurality of solenoid valves to control supply and drain of a line pressure, which is used to actuate a plurality of shift control valves for controlling actuation of said forward/reverse hydraulic servomechanism and said hydraulic clutches; forward drive selection detecting means for detecting whether said forward drive power transmission paths are selected by said forward/reverse hydraulic servomechanism; and actuation command signal detecting means for detecting actuation command signals which are sent to said solenoid valves; wherein: if said forward drive selection detecting means detects that said forward/reverse hydraulic servomechanism has selected said forward drive power transmission paths, and if said actuation command signal detecting means detects that actuation command signals are being sent to set a forward drive speed change ratio, then said solenoid valves are allowed to actuate in response to said actuation command signals wherein, said forward drive selection detecting means comprises a hydraulic switch to detect a forward drive hydraulic pressure which is supplied to said forward/reverse hydraulic servomechanism to select said forward drive power transmission paths.