Power seat driving apparatus for vehicle

A power seat driving apparatus for a vehicle comprising:

• a moving unit adapted to be arranged between a seat and a vehicle floor so as to move the seat relative to the vehicle floor;
• and
• a decelerating mechanism connected to the moving unit so as to decelerate a driving force outputted by a power supply and transmit the decelerated driving force to the moving unit;
• wherein
• the deceleration mechanism includes:
• a driving gear;
• a driven gear engaging with the driving gear and driven to rotate while decelerating a rotational speed of the driving gear;
• a supplemental gear coaxially connected to the driven gear in an interlocking manner, made of a resin material having elasticity and lower rigidity than the driven gear, having a larger tooth thickness than a tooth thickness of the driven gear by an amount corresponding to a backlash, and engaging the driving gear together with the driven gear;
• and
• a housing accommodating and rotatably supporting the driving gear, the driven gear and the supplemental gear.