Variable compression ratio apparatus

A variable compression ratio apparatus mounted on an engine receiving combustion force of mixed gas from a piston to rotate a crankshaft, and configured to change a compression ratio of the mixed gas, the apparatus comprising:

• an eccentric bearing assembly engaged with the piston through a piston pin, and including:
• an eccentric ring having an eccentric hole so that the piston pin is rotatably installed therethrough while being eccentric to the eccentric ring;
• and
• an eccentric link connected to the eccentric ring to transfer rotation force to the eccentric ring;
• a first connecting rod rotatably installed at a one side in an axial direction of the eccentric ring;
• a second connecting rod rotatably installed at the other side in the axial direction of the eccentric ring;
• and
• a control shaft connected to the eccentric link to rotate the eccentric bearing assembly by transferring the rotation force to the eccentric ring,
• wherein the eccentric ring includes expanded portions at both sides in the axial direction thereof so that the first and second connecting rods are rotatably installed at the expanded portions, respectively, and
• wherein one ends of the first and second connecting rods are formed with mounting holes respectively, the expanded portions being rotatably inserted therein, and the other ends of the first and second connecting rods are rotatably connected to the crankshaft while being eccentric to the crankshaft.