Door opening and closing mechanism for a balance windshield

A door opening and closing mechanism for a balance windshield, comprising:

• a support case having a ceiling portion and a wall portion protruding downward from the ceiling portion, the support case provided at an upper end portion of an opening of a balance windshield;
• a guide rail protruding laterally from the wall portion of the support case;
• and
• a sliding door comprising a handle provided at a lower front end portion of the sliding door and a plurality of guide rollers held in a rollable state, respectively, in a plurality of bearing portions that are provided at an upper end portion of the sliding door, in which the guide rail suspends and retains the sliding door by the guide rollers, wherein
• the guide rollers each have a shaft and a roller held on the shaft,
• the guide rollers are held rotatably in the bearing portions by the shafts and arranged rollably on the guide rail,
• the bearing portions and the rollers are each arranged to have a clearance with the ceiling portion, and
• the clearance between the rearmost bearing portion of the sliding door and the ceiling portion of the support case is formed wider than the clearance between an upper end portion of the roller held in the rearmost bearing portion of the sliding door and the ceiling portion of the support case.