| 摘要 |
PURPOSE:To perform rapid completion of gear shift by a method wherein during shift from a continuously variable shift transmission system to a discontinuously variable shift transmission system, when the working oil pressure of a clutch and a continuously variable shift pressure are drained, the working oil pressure of a clutch is additionally drained. CONSTITUTION:During shift from a continuously variable shift transmission system to a fixed ratio transmission system by means of a panic brake, a shift motor 41 restores a shift command valve 40 and a shift control valve 42 to an overstroke position. A pressure in an input pulley chamber 8b and an engag ing pressure in a high clutch 21 are drained through a drain port 42a to effect shift. In this case, since the content volume of the input pulley chamber 8b is high, drain of the engaging pressure of the high clutch 21 is tinged with a delay. But, since a means 43 formed with ports 40c and 40d of the shift com mand valve 40 communicates a circuit 64 with the drain port 40d in a overstroke position, a high clutch pressure is rapidly drained through an additional drain. Rapid shift is effected in a manner described above, restarting after panic brake can be reliably effected by a discontinuous shift transmission system. |
