| 摘要 |
A multiple-transmission-ratio transmission arrangement includes at least first and second transmission-ratio-establishing units, for example brake bands and/or clutches, having hydraulically activated and unactivated states and operative in the hydraulically activated state for establishing respective first and second transmission ratios. An arrangement for changing the transmission ratio of the transmission arrangement comprises, in combination, a source of hydraulic activating fluid and conduits connected to the source and to the hydraulically activatable transmission-ratio-establishing units. Electrically controllable valves in the conduits are operative for alternately permitting and preventing the supply of hydraulic activating fluid to the transmission-ratio-establishing units. An electrical transmission-ratio-selecting arrangement is connected to the valves and is operative for charging the transmission ratio of the transmission arrangement by causing the valves to effect a change of state of one of the units and an opposite change of state of the other of the units. Included is an electronic timing arrangement operative during a change of transmission ratio for delaying the change of state of one of the units until after the change of state of the other of said units has been effected.
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