| 摘要 |
A gear control system intended in particular for an electrically operated automatic transmission of layshaft design comprises the following elements: a hydraulic system with pressurised lines; a pump (5) for generating a system pressure; a first pressure reduction valve (6) for adjusting the system pressure; and switching elements (1, 2, 3, 4) at least one of which takes the form of a higher gear (1) for forward drive, another takes the form of a low gear (2) for forward drive, another takes the form of a switching element for reverse drive (3) and yet another takes the form of a clutch (4). The switching elements can be actuated by pressure via the pressure lines with pilot valves (10, 11, 12), and switching of one of the switching elements (1, 2, 3) or clutch (4) is defined by the switching position of the pilot valves (10, 11, 12) and of a multipath valve (16) connected upstream of the switching elements (1, 2, 3). The transmission control system has a reserve switching device which in the event of a voltage drop applies pressure to the multipath valve (16) to switch one of the switching elements (1, 2, 3) for forward or reverse drive, as well as a switch-back safety device which, when the reserve switching device is activated, prevents switching back from a higher gear (1) to a low gear (2), and an anti-transmission-blocking switching device which, if the clutch (4) and one of the switching elements (1, 2, 3) are actuated simultaneously, shuts off the pressure supply to the pilot valve (12) of the clutch (4) and to the pilot valve (11) of the switching element (2) and switching element (3). |
