| 摘要 |
PURPOSE:To accomplish smooth shift and to improve durability of a transmission by providing a relief passage communicating with low-pressure side where an electrohydraulic control valve controlled according to a speed change signal is disposed in a pressure oil feed passage leasing to an electromagnetic selector and a shift valve. CONSTITUTION:A relief passage 20 communicating with the low-pressure side are provided in feed passages 15, 16 leading to electromagnetic selectors 11a-11c and solenoid shift valves 13a, 13b, and an electrohydraulic control valve 21 is disposed in the relief passage 20. The electrohydraulic control valve 21 pushes a needle valve 22 for opening and closing the relief passage 20 in the closing direction by a spring 24, and actuates the relief passage 20 in the opening direction by applying voltage to a solenoid 23. The electrohydraulic control valve 21 is controlled according to a signal sent from a computer at the time of speed change.
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