| 摘要 |
A hydraulic actuation system for an automated transmission system including an active clutch includes; a hydraulic clutch actuator controlling engagement of the clutch, the hydraulic control actuator being preloaded towards a disengaged position of the clutch, whereby pressure above a first predetermined value is required in order to move the clutch to a predetermined position; first and second gear engagement actuators for controlling the selection and engagement of a selected gear ratio; a source of hydraulic fluid under pressure, a hydraulic fluid reservoir; a clutch control valve for selectively connecting the clutch actuator to the source of hydraulic fluid under pressure or to the reservoir; a gear engagement control valve for selectively connecting each gear engagement actuator to the source of hydraulic fluid under pressure or to the reservoir; and a changeover valve situated between the gear engagement control valve and the first and second gear engagement actuators, said changeover valve in a first position connecting the first gear engagement actuator to the gear engagement control valve and the second gear engagement actuator to the reservoir and, in a second position, connecting the second gear engagement actuator to the gear engagement control valve and the first gear engagement actuator to the reservoir, the changeover valve being shifted from its first position to its second position when pressure in the clutch actuator rises above a second predetermined value, the second predetermined value being lower than the first predetermined value.
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