| 摘要 |
PURPOSE:To contrive the fail safe by controlling communication with each port and its blocking by a shift limiting valve actuating a control solenoid valve, when a vehicle is in advancing at a predetermined speed or more. CONSTITUTION:In a condition that a vehicle is in advancing at a car speed 42 not less than 5km/h, a control unit 40 turns on a solenoid valve SR, moving a shift limiting valve 110 to the right by a pressure of oil from an oil path 125, blocking connection passages 126 to 128 by a spool 11, generating no flow of working fluid to R, 2nd, 1st brakes and holding the neutral condition, accordingly, even when a misshift is performed to an R-range, a transmission performs no speed change to a reverse shift. While in whatever speed change position a shift tower may be placed, the solenoid valve SR is turned on for a car speed not less than 6km/h, generating a low pressure in the passage 125, even when a misshift is performed in a D-position to 2-, 1-speed positions, no flow of working fluid is generated in the connection passages 127, 128, and no shift is performed. Thus, the fail safe can be contrived. |
