| 摘要 |
PURPOSE:To eliminate the need of a one-way clutch by controlling an accumulator relay valve for selectively connecting a designated hydraulic servo to an oil pressure source or to a drain port. CONSTITUTION:In case of shifting from the first speed to the second speed, for example, the moment supply pressure to a hydraulic servo B-2 is increased sufficiently and the reaction force to a brake B3 becomes naught, a solenoid valve S3 is turned on and a spool 52 of a timing valve 50 is moved so that oil pressure in a hydraulic servo B-3 is released at a stroke from a drain port 10D of a manual valve through a passage 7, a timing valve 50 and an oil path 3. Then, the oil pressure in the hydraulic servo B-3 is instantaneously discharged to remove restraint on rotation of a ring gear and speedily shift a speed range to the second speed.
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