Vehicle door driving apparatus

A vehicle door driving apparatus, comprising:

• a drive mechanism secured inside a vehicle door, wherein the drive mechanism opens and closes a door opening formed in a vehicle body, the drive mechanism including a motor and a drum, wherein the drum is rotated by the motor;
• and
• a rope member wound about the drum and coupled to the vehicle body,
• wherein the vehicle door is opened and closed as rotation of the drum is converted to force applied to the vehicle body via the rope member,
• wherein the drum is arranged inside the vehicle door such that the drum at least partially overlaps with a space having a dimension in the lateral direction of the vehicle defined by an outer shape of the motor,
• the drive mechanism including:
• a first small-diameter gear portion coupled to a rotary shaft of the motor to rotate integrally with the rotary shaft;
• a transmission gear, which is freely rotational about an axis extending in the lateral direction of the vehicle, the transmission gear including a first large-diameter gear portion, which is meshed with the first small-diameter gear portion and forms a gear pair with intersecting axes or a hypoid gear together with the first small-diameter gear portion, and a second small-diameter gear portion, which is arranged on an opposite side of the first large-diameter gear portion in the axial direction of the transmission gear;
• a sun gear, which is freely rotational about an axis extending in the lateral direction of the vehicle, the sun gear including a second large-diameter gear portion, which is meshed with the second small-diameter gear portion, and a sun gear portion, which is arranged on the same side of the second large-diameter gear portion as the rotary shaft;
• a ring gear arranged coaxially with the sun gear and radially outward of the sun gear portion, the ring gear serving as a fixed shaft;
• and
• a carrier including a planet gear meshed with the sun gear portion and the ring gear, and the carrier being coupled to the drum to rotate integrally with the drum.