| 摘要 |
An automatic manual transmission (AMT) includes a system for prioritising the supply of hydraulic pressure between a clutch actuating circuit and a gear selector actuating circuit. A clutch pressure circuit including a clutch pressure valve 114 and a clutch actuator 112, is connected to an hydraulic source, eg pump 102, and a priority valve 110 is arranged between the source and a gearshift circuit including gearshift control valves 120 and gearshift actuator 118. The priority valve 110 is configured to switch between a first position in which the gearshift circuit and an auxiliary flow conduit 122 (which returns fluid to the hydraulic supply or feeds an auxiliary circuit e.g. an oil or clutch cooling circuit) is connected to the hydraulic supply; a second position in which the supply of flow to the gearshift circuit is maintained but the supply of flow to the auxiliary circuit is disabled, and a third position in which the supply of flow to both the gearshift circuit and the auxiliary circuit is disabled. The priority valve 110 is configured to switch in response to a drop in supply pressure below predetermined thresholds. |
