In a belt type continuously variable transmission in which a pulley shaft (SP) is supported by bearings (31, 32) provided at two positions that are apart from each other in an axial direction of the pulley shaft (SP) and a supply oil passage for supplying hydraulic fluid to a pulley hydraulic chamber (40A, 40B) includes a radial direction oil passage (SPB) that is formed in the pulley shaft (SP,), the radial direction oil passage (SPB) is formed on an outside of an area between the above-mentioned two positions. Also, one of the bearings (32) is provided near the radial direction oil passage (SPB) and on an outer surface side of a cylinder member (70) whose inner surface side forms the pulley hydraulic chamber (40B) for a movable sheave (38) that is fixed to the pulley shaft (SP). With this structure, concentration of stress on the radial direction oil passage can be avoided, and therefore strength of the pulley shaft can be secured.

Belt-type continuously variable transmission

A continuously-variable transmission (CVT) assembly is employed for transmitting a torque from an external power-source The CVT includes a variable-diameter input pulley and a variable-diameter output pulley, each having a respective range of adjustment The CVT also includes a continuous torque-transmitting element extending between the variable-diameter input pulley and the variable-diameter output pulley, and thereby operatively connecting the input pulley to the output pulley The CVT additionally includes a first elastic element having a first zero stiffness over the range of adjustment of the variable-diameter input pulley and configured to apply a first constant spring clamping force via the input pulley to the continuous torque-transmitting element Furthermore, the CVT includes a second elastic element having a second zero stiffness over the range of adjustment of the variable-diameter input pulley and configured to apply a second constant spring clamping force via the output pulley to the continuous torque-transmitting element

Continuously-variable transmission

A control unit is imparted a function in which the engagement of a high-speed clutch which had been in disengagement until then is started (or the energization of a high-speed clutch solenoid switch valve is put to ON) before a change-speed of a toroidal continuously variable transmission has reached an optimal value for performance of a mode switch (a point A, for example, 0.46 in a speed increasing ratio) or at a point B (for example, 0.6 in the speed increasing ratio). As a result of this, the problem can be solved.

Continuously Variable Transmission

In a belt type continuously variable transmission, the oil for the canceler oil chamber and the oil for lubricating the endless belt are commonly used to reduce the required amount of oil to be supplied. The gear shift control oil is supplied to the pulley oil chamber of the driven pulley mounted on the output shaft of the belt type continuously variable transmission through a feed pipe, oil holes of a plug, an oil groove, oil holes of the output shaft and oil holes of the movable pulley half. The lubricating oil supplied to a first in-shaft oil chamber of the output shaft is further supplied through the oil holes of the output shaft to the canceler oil chamber of the driven pulley and also from the first in-shaft oil chamber through a throttle in the plug, the second in-shaft oil chamber and the oil holes of the output shaft to the endless belt.

Belt type continuously variable transmission

A belt-type continuously variable transfer system ( 15 ) includes a driving pulley assembly ( 20 ), a driven pulley assembly ( 22 ) and a V-shaped belt ( 24 ) engaged to transfer rotary power therebetween. The driven pulley assembly ( 22 ) can include a ratio adjustment mechanism ( 46 ) that adjusts the position of a rear sheave ( 40 ) relative to a forward sheave ( 42 ). The adjustment mechanism ( 46 ) includes a motor ( 170 ) and a worm gear mechanism ( 171, 172 ) that rotates an actuation screw ( 154 ). Rotation of the actuation screw ( 154 ) is reacted by a split nut ( 158 ) so that as the screw ( 154 ) rotates is translated along the axis (B) of the driven pulley assembly ( 22 ). Translation of the actuation screw ( 154 ) exerts pressure against the rear sheave ( 40 ) to push it toward the forward sheave ( 42 ), thereby altering the drive ratio of the pulley assembly. In one feature, the driven pulley assembly ( 22 ) includes a fail-safe mechanism ( 48 ) that operates when power is supplied to the motor ( 170 ) to hold the split nut ( 158 ) together. Once power is disrupted, the fail-safe mechanism ( 48 ) allows the components ( 158 a-c ) of the split nut ( 158 ) to be separated, disrupting the threaded engagement with the actuation screw ( 154 ). At this point, the actuation screw ( 154 ) is driven forward by a compression spring ( 190 ), thereby driving the rear sheave ( 40 ) forward to a predetermined drive ratio position. In another aspect of the invention, the driving pulley assembly ( 20 ) includes an idler pulley portion ( 65 ) radially inboard from the normal driving sheave surface ( 29, 31 ).

Continuously variable belt drive system

A pulley device includes a moveable conical pulley component which is moveable to a stationary conical pulley component by a servo motor. The servo motor includes a cylinder fixedly held with respect to a shaft portion of the stationary conical pulley component, and a piston fixed to the moveable conical pulley component and slidably engaging the cylinder. The servo motor also includes an auxiliary cylinder reduced in diameter than the cylinder and fixed with respect to the shaft portion, and an auxiliary piston fixed to the moveable conical pulley component. The auxiliary piston is received in the auxiliary cylinder.

Pulley device for continuously variable transmission

A vehicle drivetrain control system reduces the torque of a clutch to a desired level determined as a function of the engine speed during a predetermined period of time initiated by depression of a foot brake. The function is representative of torque versus engine speed characteristic of the drivetrain during coasting operation.

Hirofumi Okahara

Papers

Pulley device for continuously variable transmission

Vehicle drivetrain control including CVT