Continuously variable transmission

A continuously-variable-ratio transmission capable of operation in at least first and second regimes, and adapted for use in a vehicle having first and second laterally-displaced rotary driving members and steered by differential rotation of such members, comprising:

• first and second ratio-varying units having first and second rotary output members rotatable about first and second output axes, respectively;
• associated first and second epicyclic gear sets each having first and second input axes by which said first and second epicyclic gear sets are connected to said first and second rotary output members, respectively, and each epicyclic gear sets having three components, namely one each of sun, carrier and annulus components, a first one of said three components of said first and second epicyclic gear sets being connected respectively to first and second driving members;
• a mechanism for changing between said regimes, in which said mechanism comprises a gear combination presenting a third input axis;
• and in which said first and second input axes of said epicyclic gear sets, said third input axis of said mechanism, and said first and second output axes of said first and second ratio-varying units all coincide.

A continuously-variable-ratio transmission capable of operation in at least first and second regimes, and adapted for use in a vehicle having first and second laterally-displaced rotary driven members and steered by differential rotation of such members, comprising:

• a transmission input adapted to be driven by a prime mover of the vehicle;
• first and second ratio-varying units each having an input connected to said transmission input, and an output;
• first and second epicyclic gear sets each having three components, namely one each of sun, carrier and annulus components;
• whereby in said first regime a third and a second of said three components of said first epicyclic gear set are driven by way of said transmission input and by said output of said first ratio-varying unit, respectively, to provide drive for said first driven member from a first said component of said first epicyclic gear set, and a third and a second of said three components of said second epicyclic gear set are driven by way of said transmission input and by said output of said second ratio-varying unit, respectively, to provide drive for said second driven member from a first said component of said second epicyclic gear set;
• and in said second regime said output of said second ratio-varying unit drives said first said component of said first epicyclic gear set directly and so drives said first driven member, said output of said first ratio-varying unit drives said second said component of said first epicyclic gear set, and said third said component of said first epicyclic gear set and said output of said second ratio-varying unit drive, respectively, drive said third and said second said components of said second epicyclic gear set and so provide drive to said second driven member by way of the said first said component of said second epicyclic gear set.