| 摘要 |
An automatic transmission shift control system is provided for work vehicles, such as front-end loaders, which permits automatic shifting between first and second gears in response to vehicle speed but which inhibits downshift for a predetermined time interval after initiating reversal of the vehicle. A speed signal generator produces shift point signals at predetermined speed values and a speed logic circuit responds to the shift point signal for producing respective upshift and downshift signals. An inhibit circuit produces an inhibit signal in response to a reversing signal. The speed logic circuit is responsive to the inhibit signal for delaying the change from an upshift control signal to a downshift control signal for a time interval corresponding to the duration of the inhibit signal. The inhibit circuit is disabled when the speed decision logic circuit produces a downshift signal so that an upshift of the transmission may occur during reversal. |
