To smoothly operate a clutch without receiving influence of a rotating speed of an engine or the number of speeds in a working vehicle such as a tractor having a wet multiple disk type forward and backward movement change clutch.
An output signal of a rotating position of a forward and backward change lever 8 detected by a forward and backward movement change lever sensor 111, an output signal of a manipulated variable of a clutch pedal detected by a potentiometer 114, an output signal of the rotating speed of the engine detected by an engine rotating speed sensor 111 and an output signal of the rotating position of a sub-speed change lever 9 detected by a sub-speed change lever sensor 113 are transmitted to a controller 110. The controller 110 can selectively switch proportional solenoid valves 52 and 53 of a control valve 51 in accordance with the respective signals and control a quantity of oil fed to the wet multiple disk clutches 17F and 17R for switching forward and backward movements and oil feed directions.
MIYAMOTO MASAHIKO
ANDO NORIHIKO
