Patent ID: 8393307

Claim:
A variable compression ratio device including a piston, a crankshaft, and a connecting rod including a small end rotatably connected to the piston by a piston pin and a big end rotatably connected to the crankshaft, comprising: an eccentric bearing that contacts an exterior circumference of the piston pin, wherein an exterior circumference of the eccentric bearing contacts an interior circumference of a ring formed at the small end of the connecting rod and a central portion of the exterior circumference of the eccentric bearing is eccentric with a central portion of an interior circumference thereof; a ratchet rod slidably coupled inside the piston pin and movable along a longitudinal direction therein to make selectively a relative rotation between the eccentric bearing and the small end of the connecting rod in accordance with a longitudinal motion of the ratchet rod; a variable slider that selectively contacts one of both ends of the ratchet rod, and that is disposed at both sides of a cylinder for pushing the one of both ends of the ratchet rod in an opposite direction; and a guide plate for reciprocally moving both variable sliders along a vertical direction of the ratchet rod, wherein one end of the variable shaft is connected to the variable slider, and a sliding direction of the variable slider is controlled by a rotation of the variable shaft.