METHOD OF CONTROLLING CONTINUOUSLY VARIABLE TRANSMISSION

摘要

To enable noise reduction control in a hydrostatic continuously variable transmission. A constant-displacement hydraulic pump and a variable- displacement hydraulic motor are disposed on the driving shaft, and are connected by a closed hydraulic circuit. Occurrence of hydraulic pressure on the hydraulic motor side is prevented by changing to TOP side the angle of the movable swash plate mounted on the hydraulic motor. When specific determining conditions are satisfied during engine operation, the movable swash plate of the hydraulic motor is inclined to TOP side, to prevent occurrence of an excess play between the rotating housing on the hydraulic pump side and the pump-side plunger, thereby reducing or preventing noise occurrence. The determining conditions are as follows. (1) The signal voltage of the throttle sensor 23 indicating the throttle opening is lower than the threshold value. (2) The vehicle speed is over the threshold value. (3) The acceleration is over the threshold value. (4) The engine speed is below the threshold value. (5) The establishment of conditions (1) to (4) is over a specific period of time.