| 摘要 |
An hydraulic control system for an automatic transmission having a plurality of friction engageable devices to produce a plurality of drive ratios by selective engagement thereof, two of the engageable devices comprising friction brakes engageable to establish a second speed drive ratio through the transmission, and conduit means connecting a source of pressure to each of the brake devices and to an hydraulic accumulator. The conduit means has a first branch connected to one of the brake devices, a second branch connected to a second of the brake devices, and a logic valve is provided in the conduit means between the branches adapted to interconnect the branches and the respective servomotors for engaging the brake devices, providing equalization of the pressures at the brake devices whereby they are engaged with identical engaging force. The control circuit includes a restriction control valve, in the conduit means for the direct drive or second clutch of the transmission which is connected between the conduit means and an accumulator for the second clutch, providing an unrestricted flow of pressure to the accumulator when the clutch is being engaged and a restricted flow of pressure from the accumulator to the conduit means when the clutch is disengaged whereby disengagement of the clutch may be controlled without waiting for the stored hydraulic energy in the accumulator to be dissipated. |
