| 摘要 |
PCT No. PCT/EP91/01487 Sec. 371 Date Apr. 1, 1992 Sec. 102(e) Date Apr. 1, 1992 PCT Filed Aug. 7, 1991 PCT Pub. No. WO92/03672 PCT Pub. Date Mar. 5, 1992.A gear unit provides a number of operative ratios engaged by fluid pressure operated clutches operated by clutch actuators. These actuators are controlled by two-position flow reversing valves, one valve for each fluid pressure operated actuator. These valves are hydraulically connected in series with at least one actuator connected downstream of the last valve in the series connection and at least one actuator connected between each valve of the series. A valve control means is provided for controlling the operating sequence of the valves so that by changing the operative condition of one valve at a time the operative ratio of the gear unit can be changed to the next adjacent ratio provided by the unit in a progressive manner throughout the entire ratio range of the unit. |
