Continuously Variable Transmission For Off-Road Vehicle

A continuously variable automatic transmission for an off-road vehicle, comprising:

• a pulley stage having a primary pulley assembly and a secondary pulley assembly, the primary pulley assembly being driven by torque from an engine of the off-road vehicle, with a belt or chain transferring torque from the primary pulley assembly to the secondary pulley assembly, wherein effective diameters of the primary pulley assembly and the secondary pulley assembly where they contact the belt or chain are variable;
• a forward and reverse gear assembly which can receive torque from the secondary pulley assembly, the forward and reverse gear assembly comprising a forward driven gear and a reverse driven gear both bearing mounted on a shaft;
• and
• a shift mechanism connected to the forward and reverse gear assembly, the shift mechanism comprising:
• a shift drum having a shifting track and a biasing track, the shift drum being rotatable between at least positions for a reverse gear R, a neutral gear N, and a forward gear D;
• a shift fork controlled by the shifting track;
• a shifting driving gear sleeve coupled to the shift fork and spline-coupled on the shaft, the shifting driving gear sleeve being able to carry torque in the forward and reverse gear assembly, the shape of the shifting track controlling the shift fork to move the shifting driving gear sleeve axially between a reverse gear station wherein the shifting driving gear sleeve is in side-by-side engagement with the reverse driven gear, a forward gear station wherein the shifting driving gear sleeve is in side-by-side engagement with the forward driven gear and a neutral gear station located between the reverse gear station and the forward gear station wherein the shifting driving gear sleeve is in engagement with neither the reverse driven gear nor the forward driven gear;
• a spring bias plate seat controlled by the biasing track;
• and
• a spring-with-two-moving-ends biasing the shift fork relative to the spring bias plate seat, such that an aggregate sideways force on the shift fork in an axial direction can be controlled at least in part by relative spacing between the shifting track and the biasing track as a function of rotation of the shift drum.

A continuously variable automatic transmission for an off-road vehicle, comprising:

• a power input stage comprising:
• an input-stage driving gear receiving torque from an engine of the off-road vehicle;
• an input-stage driven gear meshingly engaged with the input-stage driving gear, wherein a relative number of teeth on the input-stage driving gear and the input-stage driven gear provides a gear reduction
• an oil pump driving gear receiving torque from the torsional vibration damper;
• an oil pump driven gear meshingly engaged with the oil pump driving gear, wherein the oil pump driven gear rotates about an axis which is parallel to rotational axes of the primary pulley assembly and secondary pulley assembly;
• and
• an oil pump powered by the oil pump driven gear;
• a pulley stage having a primary pulley assembly and a secondary pulley assembly, the primary pulley assembly being driven by torque from the input-stage driven gear of the power input stage, with a belt or chain transferring torque from the primary pulley assembly to the secondary pulley assembly, wherein effective diameters of the primary pulley assembly and the secondary pulley assembly where they contact the belt or chain are variable;
• a clutch which can transmit torque output by the pulley stage;
• a forward and reverse gear assembly which can receive torque from the clutch, the forward and reverse gear assembly comprising a forward driven gear and a reverse driven gear both bearing mounted on a shaft;
• a shift mechanism connected to the forward and reverse gear assembly, the shift mechanism comprising a shifting driving gear sleeve spline-coupled on the shaft, the shifting driving gear sleeve being able to carry torque in the forward and reverse gear assembly, the shifting driving gear sleeve being axially movable between a reverse gear station wherein the shifting driving gear sleeve is in side-by-side engagement with the reverse driven gear, a forward gear station wherein the shifting driving gear sleeve is in side-by-side engagement with the forward driven gear and a neutral gear station located between the reverse gear station and the forward gear station wherein the shifting driving gear sleeve is in engagement with neither the reverse driven gear nor the forward driven gear;
• and
• an output stage coupled to the forward and reverse gear assembly and receiving torque transmitted through the shifting driving gear sleeve, the output stage having a front output for providing torque to a pair of front wheels and a rear output for providing torque to a pair of rear wheels.