Patent ID: 7556576

Claim:
A V-belt continuously variable transmission comprising: a primary sheave disposed on a primary sheave shaft, to which a driving force of an engine is input, and arranged to define a V-groove for receiving a belt; a secondary sheave disposed on a secondary sheave shaft, from which a driving force for a driving wheel is output, and arranged to define a V-groove for receiving a belt; a V-belt received in the respective V-grooves of the primary sheave and the secondary sheave to transmit a rotational driving force between both the sheaves; the primary sheave and the secondary sheave being respectively defined by a movable sheave half and a fixed sheave half; an electric motor; a control device arranged to control the electric motor; and a sheave drive mechanism arranged to transmit a driving force of the electric motor to the movable sheave half of the primary sheave to control respective groove widths of the primary sheave and the secondary sheave; wherein the sheave drive mechanism includes: a movable tube coupled to the movable sheave half of the primary sheave so as to be rotatable with respect thereto and axially movable together therewith; a fixed tube disposed internally of and coaxially with the movable tube; a ball screw mechanism provided between the fixed tube and the movable tube; an outer peripheral wall arranged to cover an area from the fixed tube to an outer periphery of the movable tube; a seal member provided between the movable tube and the outer peripheral wall to seal an internal space arranged to enclose a working surface of the ball screw mechanism; and a communication path arranged to communicate the internal space with an outside of the outer peripheral wall.