| 摘要 |
PURPOSE: A hydraulic controller of an automatic transmission is provided to prevent the no-load state of an engine by delaying the line pressure at a specific pressure via a first line, to exclude the shift shock, and to compact the structure of a valve body by reducing the number of check balls and lands. CONSTITUTION: An orifice(Or1) is installed on a first line(L1) communicating with a first clutch(C1) and a switch valve(10) connected in the D(Drive) range. A check ball(CB1) is installed on a second line(L2) diversified from the first line. The check ball is connected with the switch valve via a fourth line(L4). The switch valve is connected with a pressure control valve(14) via a fifth line(L5). The fifth line is selectively communicated with an exhaust port(EX) with response to the operation of the pressure control valve. In speed change from D range to R(Reverse) range, the line pressure applied to the first clutch is released to the second line via the first line. Then, the check ball is opened, and the initial flow rate is released rapidly. If the pressure in the first clutch is balanced with the force of a spring, the check ball is closed. The released pressure in the first clutch is sustained for a specific time.
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