Door driving system and refrigerator including the same

A refrigerator comprising:

• a hinge;
• a door that opens and closes via the hinge;
• a motor to output power;
• a planetary gear unit;
• and
• at least one drive gear coupling the planetary gear to the motor,
• wherein the at least one drive gear and the planetary gear unit cooperate together to transfer the power output by the motor to the hinge to move the hinge and thereby open or close the door, without transferring a turning force generated by the hinge to the motor.

A refrigerator comprising:

• a door;
• a hinge connected to the door;
• a motor;
• at least one driving gear;
• a sun gear engaged with the motor via the driving gear;
• a planetary gear engaged with the sun gear;
• an internal gear engaged with the planetary gear and configured to transfer power generated by the motor to the hinge to move the hinge and thereby open or close the door;
• and
• a carrier having a locked state in which the carrier does not rotate and an unlocked state is which the carrier is rotatable,
• wherein the sun gear, the planetary gear, the internal gear and the carrier cooperate together so that
• when the sun gear is rotated by power of the motor with the carrier in the locked state, the rotation of the sun gear causes the planetary gear to rotate about a rotation axis, which causes the internal gear to rotate in a direction opposite to a direction of rotation of the sun gear, to thereby output the power of the motor to the internal gear to move the hinge,
• when the sun gear is rotated by power of the motor with the carrier the unlocked state, the rotation of the sun gear causes the planetary gear to revolve, without rotation of the internal gear, which causes the carrier to rotate in the direction of rotation of the sun gear, so that the power of the motor is thereby output to the carrier and not transferred to the internal gear, and
• when the hinge generates a turning force with the carrier in the locked state, the internal gear is rotated by the turning force, with the at least one driving gear preventing the sun gear from rotating, to cause the planetary gear to revolve, which causes the turning force to be transferred to the carrier and not to the motor, and, when the turning force transferred to the carrier causes a force greater than or equal to a specific level to be applied to the carrier, the carrier moves from the locked state to the unlocked state to cause the carrier to rotate.