| 摘要 |
PURPOSE:To change the speed of a motor vehicle with a speed change point set in accordance with the actual running conditions, by using a valve for selectively supplying to a shift valve a governor pressure from one of a plurality governor valves, whereby governor pressure are regulated, and a control means for actuating the governor pressure supplying valve. CONSTITUTION:A plurality of governor valves 112, 113 are provided, whereby governor pressures to be applied to shift valves 105, 107 are regulated. Between the governor valves 112, 113 and shift valves 105, 107, a governor pressure change- over valve 115 is provided, whereby a governor pressure from the governor valves 112, 113 is selectively supplied to the shift valves 105, 107. The governor pressure change-over valve 115 is provided with a control means 116 for actuating the same valve 115. Thus, a governor pressure for use in changing the speed of a vehicle can be freely selected at the driver's own will when the vehicle runs on a mountain road or when the vehicle has a heavy load, to change the shift-up time. Accordingly, unnecessary automatic speed change can be minimized, and a vehicle can be driven speedily and smoothly. |
