Toroidal type continuously variable transmission

A toroidal continuously variable transmission comprising:

• a transmission housing;
• a torque input shaft;
• an input disc and an output disc which are supported around said torque input shaft with inner surfaces thereof opposed to each other such that they are free to rotate with respect to said torque input shaft;
• a pressuring device which is provided between an outer surface of said input disc and said torque input shaft and which rotates said input disc together with said torque input shaft while pressing said input disc toward said output disc;
• a trunnion which rocks about a pivot disposed in a plane which intersects central axes of said input disc and said output disc;
• a power roller held between the opposed inner surfaces of said input disc and said output disc while the power roller is rotatably joined to said trunnion;
• a first ball-and-roller bearing which is provided between said torque input shaft and a first fixed portion of said transmission housing and which supports a first thrust load applied from said torque input shaft in a direction parallel to said torque input shaft as said pressing device is actuated;
• and
• a second ball-and-roller bearing which is provided between said output disc and a second fixed portion of said transmission housing, and which supports a second thrust load applied from said output disc in a direction opposite from said first thrust load as said pressuring device is actuated;
• wherein a hydraulic force generator provided in a position adjacent to said first ball-and-roller bearing and said second ball-and-roller bearing reduces said first thrust load applied to said first ball-and-roller bearing and said second thrust load applied to said second ball-and-roller bearing by:
• a hydraulic force in the opposite direction from the direction in which said first thrust load is applied to a first bearing race positioned on the input end of said first thrust load of said first ball-and-roller bearing;
• and
• a hydraulic force in the opposite direction from the direction in which said second thrust load is applied to a second bearing race positioned on the input end of said second thrust load of said second ball-and-roller bearing;
• thereby reducing the rotational resistance of said first ball-and-roller bearing and the rotational resistance of said second ball-and-roller bearing;
• said hydraulic force in the opposite direction of action of said first thrust load and said hydraulic force in the opposite direction from the action of said second thrust load are respectively generated by an oil supplied into a first cylinder bore and a second cylinder bore through a common oil passage port formed through a third fixed portion of said transmission housing and a cylinder block of said hydraulic force generator;
• said first and second ball-and-roller bearings are positioned on one side of said input disc.