US 7,727,106 B2 · Continuously variable transmission

Abstract

A variable ratio transmission for mechanically coupling an input member to an output member, the variable ratio transmission allowing the conversion of an input rotational motion of the input member into an output rotational motion of the output member, the input rotational motion having an input speed and an input torque and the output rotational motion having an output speed and an output torque. The variable ratio transmission includes a variable ratio transmission assembly mechanically coupled to the input member and to the output member for rotating the output member at the output speed in response to the input member being rotated at the input speed, the variable ratio transmission assembly defining a transmission ratio between the output speed and the input speed, the transmission ratio being variable; and a ratio controller mechanically coupled to the variable ratio transmission assembly and to the input member for automatically adjusting the transmission ratio as a function of the input torque.

A variable ratio transmission for mechanically coupling an input member to an output member, said variable ratio transmission allowing the conversion of an input rotational motion of said input member into an output rotational motion of said output member, said input rotational motion having an input speed and an input torque and said output rotational motion having an output speed and an output torque, said variable ratio transmission comprising:

a variable ratio transmission assembly mechanically coupled to the input member and to the output member for rotating the output member at the output speed in response to the input member being rotated at the input speed, said variable ratio transmission assembly defining a transmission ratio between the output speed and the input speed, said transmission ratio being variable;
and
a ratio controller mechanically coupled to said variable ratio transmission assembly and to the input member for automatically adjusting the transmission ratio as a function of the input torque, said ratio controller including:
an actuating member mechanically coupled to the input member;
and
a ratio defining component including a ratio defining surface, said ratio defining component being mechanically coupled to said actuating member and to said variable ratio transmission assembly for transmitting the input torque to said variable ratio transmission assembly, said ratio defining surface being disposed such that a variation in the input torque causes a predetermined variation of said transmission ratio;
said actuating member being mechanically coupled to said variable ratio transmission assembly in a manner such that a movement of said actuating member relatively to said ratio defining surface causes said predetermined variation of said transmission ratio;
said actuating member being mechanically coupled to said ratio defining component such that said variation in the input torque causes said actuating member to move in a predetermined direction relatively to said ratio defining component;
said actuating member being movable along said ratio defining surface between a high ratio position wherein said transmission ratio is maximal and a low ratio position wherein said transmission ratio is minimal, said variable ratio transmission further comprising a biasing element for biasing said actuating member towards an equilibrium position;
said ratio defining component including a substantially cylindrical shell defining a longitudinal axis, said cylindrical shell defining a shell internal surface and a shell external surface, said cylindrical shell including an aperture extending between said shell internal surface and said shell external surface, said ratio defining surface extending at the periphery of said aperture between said shell internal surface and said shell external surface, said ratio defining surface having a pitch relatively to said longitudinal axis;
said variable ratio transmission assembly including a toroidal transmission stage, said toroidal transmission stage including:
an input disc mechanically coupled to and driven by the input member;
an output disc mechanically coupled to and driving the output member, said output disc being rotatable relative to said input disc;
a plurality of traction rollers interposed between said input disc and said output disc;
and
a plurality of substantially elongated support members each supporting a respective traction rollers, said support members defining each a respective roller longitudinal axis about which said respective traction roller is rotatable,
wherein said support members are mechanically coupled to said actuating member so that said movement of said actuating member relatively to said ratio defining surface causes said predetermined variation of said transmission ratio by changing an orientation of said roller longitudinal axes relatively to said input and output discs.

14 more elements

Continuously variable transmission

Life of this patent

Continuously variable transmission

Life of this patent

Abstract

Claims10