Sliding door drive device

1. A sliding door drive device being fixed to a body panel of a vehicle and moving a sliding door of the vehicle in an opening direction and a closing direction, the sliding door drive device comprising:

a guide frame being curved in such a way that an end of the guide frame in the closing direction is positioned more inward in a vehicle widthwise direction than an end in the opening direction when the guide frame is fixed to the body panel;

a first driven pulley and a second driven pulley being supported at both ends of the guide frame in a longitudinal direction, respectively;

a belt being wrapped around the first driven pulley and the second driven pulley; and

a belt drive part driving the belt, wherein

the guide frame includes a guide wall guiding the belt between the first driven pulley and the second driven pulley, the guide wall including a curved part with an inner side facing the body panel, and

the sliding door drive device further comprises a sliding part sandwiching the belt with the inner side of the curved part of the guide wall and sliding on the belt.

2. The sliding door drive device according to claim 1 , wherein

the sliding part is a plate-shaped sliding plate curved along the curved part.

3. The sliding door drive device according to claim 2 , wherein,

axes of rotation of the first driven pulley and the second driven pulley extend in an axial direction,

the guide frame includes:

a bottom wall and an upper wall sandwiching the guide wall in the axial direction across the guide frame in the longitudinal direction; and

a support wall extending from the bottom wall to face the inner side of the curved part of the guide wall and supporting the sliding plate in a state of being in contact with the sliding plate.

4. The sliding door drive device according to claim 3 , wherein,

the support wall extends from the bottom wall in a height direction,

the upper wall of the guide frame includes a contact part sandwiching the sliding plate with the bottom wall in the height direction.

5. The sliding door drive device according to claim 3 , wherein

the sliding plate includes a body part supported by the support wall, and a locking part locked to the bottom wall on both sides of the body part in the longitudinal direction.

6. The sliding door drive device according to claim 1 , wherein,

the belt slides on the sliding part on a sliding surface,

the belt includes a belt body made of an elastomer and a covering layer including the sliding surface and covering the belt body, and

a coefficient of friction between the covering layer and the sliding part is lower than a coefficient of friction between the belt body and the sliding part.

7. The sliding door drive device according to claim 6 , further comprising

a drive pulley supported by the guide frame and driven by the belt drive part, wherein

an axis of rotation of the drive pulley has a skew positional relation with axes of rotation of the first driven pulley and the second driven pulley, and

the belt twisted between the first driven pulley and the second driven pulley is wrapped around the drive pulley.

8. The sliding door drive device according to claim 1 , wherein

the vehicle includes an upper rail placed above a door opening to be opened and closed by the sliding door, a lower rail placed below the door opening, and a center rail placed at a position advanced from the door opening in the opening direction and between the upper rail and the lower rail in a vertical direction,

the upper rail, the lower rail, and the center rail define an opening-closing direction of the sliding door, and

the guide frame is fixed to the body panel in such a way as to run along the center rail.