Slide door support device

A slide door support device supporting, at a vehicle body, a slide door that opens and closes a door opening formed on a side surface of the vehicle body, comprising:

• a first lower rail arranged at a lower end portion of the door opening;
• a second lower rail arranged at a lower end portion of the door opening and on an inner side of the first lower rail in a vehicle width direction;
• and
• a lower guide unit connected to a lower end portion of the slide door, wherein
• the first lower rail includes a straight portion extending to a vehicle front, and a curved portion curved so as to extend inward in a vehicle width direction as a position shifts from a front end of the straight portion to a vehicle front,
• the second lower rail includes a straight portion extending to a vehicle front, and a curved portion curved in such a way that a distance from the first lower rail gradually decreases as a position shifts from a front end of the straight portion to a vehicle front,
• the lower guide unit includes:
• a first lower guide roller moving along the first lower rail;
• a second lower guide roller moving along the second lower rail;
• a lower fixed portion fixed to the slide door;
• a lower rotational arm including a proximal end portion connected so as to be rotatable relative to the lower fixed portion and supporting the first lower guide roller and the second lower guide roller at positions closer to a distal end than the proximal end portion;
• and a pressing member pressing the lower fixed portion,
• an angle made by the lower fixed portion and the lower rotational arm is assumed to be an arm angle,
• when the first lower guide roller moves along a straight portion and a curved portion of the first lower rail, and the second lower guide roller moves along a curved portion of the second lower rail, the arm angle gradually decreases as an opened degree of the slide door decreases, and the pressing member presses the lower fixed portion in a direction of increasing the arm angle.