Opening-and-closing body driving device

An opening-and-closing body driving device for coupling a vehicle body having an opening and an opening-and-closing body configured to open and close the opening, and for driving the opening-and-closing body by extending and contracting in an axial direction, the opening-and-closing body driving device comprising:

• an extendable unit including a spindle extending in the axial direction, a nut configured to move in the axial direction accompanying with rotation of the spindle, a rod configured to move in the axial direction together with the nut, a bearing configured to rotatably support the spindle, and a guide tube configured to support the spindle via the bearing and guide movement of the nut;
• and
• a driving unit including a driving portion configured to drive the spindle and a housing having a cylindrical shape and configured to accommodate the driving portion, wherein
• the guide tube includes an insertion portion configured to be inserted into the housing along the axial direction, and an inner tube configured to allow movement of the nut in the axial direction and restrict rotation of the nut,
• the insertion portion includes an inner peripheral wall that has a cylindrical shape and into which the bearing is fitted, and an outer peripheral wall that has a cylindrical shape and that is fitted into an end portion of the housing, and
• when a direction in which the insertion portion is inserted into the housing is defined as an insertion direction, a surface of the bearing facing a direction opposite to the insertion direction is defined as a first reference surface, and a surface of the housing facing a direction opposite to the insertion direction is defined as a second reference surface, a distance from the first reference surface of the bearing to a distal end of the inner peripheral wall is longer than a distance from the second reference surface of the housing to a distal end of the outer peripheral wall in the axial direction.