Seat slide device for vehicle

A seat slide device for a vehicle, comprising:

• a first rail adapted to extend in a vehicle front-rear direction, wherein the first rail includes:
• a first horizontal wall;
• a first vertical wall that extends from at least one end in a width direction of the first horizontal wall;
• and
• a first flange that projects in the width direction from a distal end of the first vertical wall to overhang the first horizontal wall and is folded back toward the first horizontal wall;
• a second rail, which is coupled to the first rail to be movable in the vehicle front-rear direction, wherein the second rail includes:
• a second vertical wall that is arranged on an opposite side of the first vertical wall from the first flange in the width direction and has an end portion close to the first horizontal wall;
• a second flange that projects in the width direction from the end portion of the second vertical wall toward the first vertical wall and is folded back toward an area between the first vertical wall and the first flange;
• and
• a joining wall that is arranged between the second vertical wall and the second flange;
• a first ball guide that is formed in a coupling portion between the first horizontal wall and the first vertical wall;
• a second ball guide that is formed in a basal portion of the second flange;
• a first ball that is rotationally arranged between the first ball guide and the second ball guide;
• and
• a restricting member that projects from a portion of the first horizontal wall that is closer to a distal end of the first rail than at least the first ball in the vehicle front-rear direction and reduces a vertical space between the joining wall and the first horizontal wall, wherein the restricting member contacts the joining wall when the second vertical wall is deformed due to a load that is applied to produce pushing force between the first ball and the second rail.