Control system for continuously variable transmission

A control system for a continuously variable transmission having a starting clutch actuator for actuating a starting clutch disposed in a power transmission path from an input shaft to an output shaft, for selectively transmitting power along said power transmission path, said control system comprising:

• a solenoid-operated control valve for generating a controlling hydraulic pressure to be supplied to said starting clutch actuator in response to a controlling current;
• hydraulic pressure generating means for generating a hydraulic pressure corresponding to the rotational speed of an engine which rotates the input shaft;
• a directional control valve for selectively connecting said solenoid-operated control valve and said hydraulic pressure generating means to said starting clutch actuator;
• and
• a solenoid-operated on-off valve for controlling said directional control valve such that when a solenoid of said solenoid-operated on-off valve is energized, said directional control valve connects said solenoid-operated control valve to said starting clutch actuator, and when the solenoid of said solenoid-operated on-off valve is de-energized, said directional control valve connects said hydraulic pressure generating means to said starting clutch actuator.

A control system for a belt-type continuously variable transmission having an input shaft, a drive movable pulley coupled to said input shaft, an output shaft, a driven movable pulley coupled to said output shaft, a V-belt trained around said drive and driven movable pulleys, a drive pulley cylinder for varying a width of said drive movable pulley, and a driven pulley cylinder for varying a width of said driven movable pulley, said control system comprising:

• a regulator valve assembly for generating a pulley controlling hydraulic pressure to be supplied to at least one of the drive and driven pulley cylinders for controlling the pulley thereof;
• an electrically operated actuator;
• a shift valve actuatable by said electrically operated actuator for supplying the pulley controlling hydraulic pressure from said regulator valve assembly to the drive and driven pulley cylinders;
• hydraulic pressure generating means for generating a hydraulic pressure corresponding to the rotational speed of an engine which rotates the input shaft;
• a shift inhibitor valve for supplying the pulley controlling hydraulic pressure from said regulator valve assembly to at least one of the drive and driven pulley cylinders through a hydraulic passage other than said shift valve under the control of the hydraulic pressure corresponding to the rotational speed of the engine;
• a directional control valve for selectively connecting said shift valve and said shift inhibitor valve to the drive and driven pulley cylinders;
• and
• a solenoid-operated on-off valve for controlling said directional control valve such that when a solenoid of said solenoid-operated on-off valve is energized, said directional control valve connects said shift valve to the drive and driven pulley cylinders, and when the solenoid of said solenoid-operated on-off valve is de-energized, said directional control valve connects said shift inhibitor valve to at least one of the drive and driven pulley cylinders.