| 摘要 |
PURPOSE: To prevent achievement of a reverse step even when a select lever is erroneously operated during forward run to be shifted from a forward range to a reverse range. CONSTITUTION: An automatic transmission comprises a governor pressure generating means to generate a governor pressure corresponding to a car speed at a forward range and a reverse range; and a manual valve 53 to generate an oil pressure from an oil pressure source as a forward pressure and a reverse pressure. A switching valve is arranged between the manual valve 53 and the hydraulic servo of a friction engagement element for reverse and between a governor pressure generating means and each shift valve and switched by a governor pressure and a forward pressure, and feeds a governor pressure to each shift valve and a reverse pressure to the hydraulic servo of a friction engagement element for reversing. The switching means comprises a spool 72; a forward pressure oil chamber 73; a governor pressure oil chamber 74; a governor pressure input port Pa; a governor pressure output port Pb; a reverse pressure input port Pc; a reverse pressure output port Pd; and an energizing means to energize a spool 72. |
