Seat slide apparatus for vehicle

A seat slide apparatus for a vehicle, the seat slide apparatus comprising:

• a lower rail which is fixed to a vehicle floor;
• an upper rail which is slidably engaged with the lower rail;
• and
• a rolling element circulation unit having a plurality of rolling elements and interposed between the lower rail and the upper rail in a state where the plurality of rolling elements is able to be circulated,
• wherein the lower rail includes a bottom wall portion which is fixed to the vehicle floor, sidewall portions which extend upward from opposite ends of the bottom wall portion in a width direction of the lower rail and the upper rail, and upper wall portions which are folded back inward in the width direction from the sidewall portions,
• the upper rail includes a main body portion which supports a seat for the vehicle at an upper side thereof, and folded-back portions which extend outward in the width direction from a lower end of the main body portion and extend upward to face the sidewall portions of the lower rail,
• the rolling element circulation unit includes a case having an annular accommodating path that accommodates the rolling elements, the rolling element circulation unit is configured such that when the case is fixed to the folded-back portion of the upper rail, the rolling elements, each of which is exposed to the outside of the case through an opening that are provided at the annular accommodating path, come into contact with an inner wall surface of the lower rail,
• between the lower rail and the upper rail, an upper rolling element circulation unit and a lower rolling element circulation unit are provided to be disposed at two positions spaced apart from each other in a vertical direction,
• the upper rail includes a pedestal portion that is provided at a tip end portion of the folded-back portion of the upper rail to extend in the width direction to face the upper wall portion of the lower rail, and
• the upper rolling element circulation unit is configured such that the rolling elements, which are exposed through the opening as the case is fixed to the pedestal portion, are in contact with the upper wall portion of the lower rail from the outside to the inside in the width direction.