Patent ID: 7951027

Claim:
A continuously variable transmission comprising: a driving portion ( 1 ) including a main cylinder ( 13 ) having an inner space in which oil ( 5 ) can be filled and operating as a pulley rotatable about a hollow tube type rotation shaft ( 12 ) which is disposed at one side of the main cylinder ( 13 ) to have a passage for passing the oil ( 5 ) there-through, and a driving shaft ( 11 ) which is disposed at the other side of the main cylinder ( 13 ) to allow the power to be inputted there-through, the hollow tube type rotation shaft ( 12 ) and the driving shaft ( 11 ) serving as a central shaft, a plurality of subsidiary cylinders ( 14 ) disposed at a circumferential surface of the main cylinder ( 13 ) and expanding in the radial direction by centrifugal force produced by rotation of the driving shaft ( 11 ), the subsidiary cylinders ( 14 ) each having belt grooves ( 19 ) at the distal end for seating at least one belt ( 6 ) thereon, and two linear bushings ( 15 ) engaged with each other by means of links ( 16 ) disposed at both sides of the subsidiary cylinders ( 14 ) and configured to move linearly on the driving shaft ( 11 ) and the rotation shaft ( 12 ); a driven portion ( 2 ) having a structure identical to that of the driving portion ( 1 ), and disposed at a position spaced apart from the driving portion ( 1 ) by a predetermined distance; belts ( 6 ) seated on the belt grooves ( 19 ) formed at the subsidiary cylinders ( 14 ) of the driving portion ( 1 ) and on the belt grooves ( 29 ) formed at the subsidiary cylinders ( 24 ) of the driven portion ( 2 ), for transmitting the power of the driving portion ( 1 ) to the driven portion ( 2 ); and an oil control portion ( 3 ) connected between the rotation shaft ( 12 ) of the driving portion ( 1 ) and the rotation shaft ( 22 ) of the driven portion ( 2 ), for controlling the oil ( 5 ) filled in the main cylinder ( 13 ) of the driving portion ( 1 ) and the oil ( 5 ) filled in the driven portion ( 2 ); wherein the subsidiary cylinders ( 14 ) disposed at the circumferential surface of the main cylinder ( 13 ) include hydraulic type subsidiary cylinders ( 141 ) configured to radially expand by means of the pressure of oil filled in an inner space thereof, and non-hydraulic type subsidiary cylinders ( 142 ), each of which has a through-hole ( 18 ) for venting air there-through.