A toroidal continuously variable transmission includes a first disc and a second disc disposed so that the first disc and the second disc are rotatable around a common rotational axis line, the first disc and the second disc facing each other; a power roller which is tiltably disposed between the first disc and the second disc; a pressing device of a loading cam type, the pressing device including a cam plate which is rotatable around the rotational axis line, and a roller unit including at least one roller sandwiched between a cam surface of the second disc and a cam surface of the cam plate; and a cam plate support supporting a back surface of the cam plate, the back surface being opposite to the cam surface of the cam plate, at a radial position conforming to a radial position of at least a portion of the roller unit.

A toroidal continuously variable transmission includes a first disc and a second disc disposed so that the first disc and the second disc are rotatable around a common rotational axis line, the first disc and the second disc facing each other; a power roller which is tiltably disposed between the first disc and the second disc; a pressing device of a loading cam type, the pressing device including a cam plate which is rotatable around the rotational axis line, and a roller unit including at least one roller sandwiched between a cam surface of the second disc and a cam surface of the cam plate; and a cam plate support supporting a back surface of the cam plate, the back surface being opposite to the cam surface of the cam plate, at a radial position conforming to a radial position of at least a portion of the roller unit.

A variator for a mechanical transmission system is disclosed. Transfer means are in rolling contact with input and output members of the variator to transfer rotary motion between them. The input member is coupled to the variator input through a first biasing device arranged to exert a first biasing force on the variator according to a first, input gain which relates input torque acting on the input member and the first biasing force. The output member is coupled to the variator output through a second biasing device arranged to exert a second biasing force on the variator according to a second, output gain which relates output torque acting on the output member and the second biasing force. The first and second biasing forces clamp the variator to provide traction. The first, input gain and second, output gain are different, which, at least in specific variator applications, optimises the traction coefficient.

A variator for a mechanical transmission system is disclosed. Transfer means are in rolling contact with input and output members of the variator to transfer rotary motion between them. The input member is coupled to the variator input through a first biasing device arranged to exert a first biasing force on the variator according to a first, input gain which relates input torque acting on the input member and the first biasing force. The output member is coupled to the variator output through a second biasing device arranged to exert a second biasing force on the variator according to a second, output gain which relates output torque acting on the output member and the second biasing force. The first and second biasing forces clamp the variator to provide traction. The first, input gain and second, output gain are different, which, at least in specific variator applications, optimises the traction coefficient.

A toroidal continuously variable transmission including input and output discs disposed to face each other so that a rotational axis of the input disc and a rotational axis of the output disc conform, each of the discs having a concave contact surface; a power roller sandwiched between the contact surfaces of discs so that the power roller is tiltable, the power roller transmitting a rotational driving force of the input disc to the output disc with a transmission ratio corresponding to a tilt motion angle; and a pressing device which presses one of the discs toward the other. When viewed from a direction of a tilt motion axis lof the power roller, the contact surface of at least one of discs has a region with a curvature that is larger than a curvature of a tilt motion trajectory of a contact surface of the power roller.

A toroidal continuously variable transmission including input and output discs disposed to face each other so that a rotational axis of the input disc and a rotational axis of the output disc conform, each of the discs having a concave contact surface; a power roller sandwiched between the contact surfaces of discs so that the power roller is tiltable, the power roller transmitting a rotational driving force of the input disc to the output disc with a transmission ratio corresponding to a tilt motion angle; and a pressing device which presses one of the discs toward the other. When viewed from a direction of a tilt motion axis lof the power roller, the contact surface of at least one of discs has a region with a curvature that is larger than a curvature of a tilt motion trajectory of a contact surface of the power roller.

A cooling arrangement to cool the rollers of a toroidal CVT is described herein. The cooling arrangement includes nozzles so configured and sized as to project cooling fluid onto the edge and onto the opposite top and bottom surfaces of the roller.

A cooling arrangement to cool the rollers of a toroidal CVT is described herein. The cooling arrangement includes nozzles so configured and sized as to project cooling fluid onto the edge and onto the opposite top and bottom surfaces of the roller.

The invention relates to a continuously variable transmission (CVT) comprising a ratio varying unit and a compound epicyclic gear set. The ratio varying unit has a rotating first side and a rotating second side, the rotational axes of the first and second sides being coaxial. The compound epicyclic gear set comprises a first set of planets, being rotationally mounted within a carrier and meshing with a sun gear. The epicyclic gear set also has a first annulus gear and a second set of planets; the second set of planets also being rotationally mounted within the carrier and meshing with a second annulus gear. One of the first or second rotating sides of the ratio varying unit is coupled to the carrier and the other of the first or second rotating sides of the ratio varying unit is coupled to the sun gear.

The invention relates to a continuously variable transmission (CVT) comprising a ratio varying unit and a compound epicyclic gear set. The ratio varying unit has a rotating first side and a rotating second side, the rotational axes of the first and second sides being coaxial. The compound epicyclic gear set comprises a first set of planets, being rotationally mounted within a carrier and meshing with a sun gear. The epicyclic gear set also has a first annulus gear and a second set of planets; the second set of planets also being rotationally mounted within the carrier and meshing with a second annulus gear. One of the first or second rotating sides of the ratio varying unit is coupled to the carrier and the other of the first or second rotating sides of the ratio varying unit is coupled to the sun gear.