As an open-close component arranged to a vehicle such as an automobile, a slide door that opens and closes in sliding manners along a guide rail is known. For example, in many wagons and station wagons, slide doors are arranged at their sides for passengers' getting on and off and loading and unloading cargos into and from vehicle sides.
This slide door has small opening space required for opening and closing, and is frequently applied for a relatively large opening portion, and a slide door itself tends to become of a larger size. Therefore, the weight of the slide door becomes heavy, and in some cases, it is difficult for a woman or a child to freely open and close it. Especially, on a slope, the slide door will not easily open owing to its own weight, or it will close abruptly, which has been a problem with the prior art. Therefore, under circumstances of increased family uses of station wagons and the likes, vehicles loaded with an automatic open-close device of a slide door that may be opened and closed easily by a women and a child have been released, and the number thereof is increasing for their convenience. As this automatic open-close device, one having a drum around which a cable attached to a slide door is wound, and an electric motor that rotates this drum is known, and by rotating the electric motor in normal and reverse directions, the slide door is automatically opened and closed.
Further, even for vehicles loaded with the automatic open-close device, there is a request for using manual open-close operation together. However, because a gear deceleration mechanism that decelerates the output of the electric motor is arranged between the electric motor and the drum, when the slide door is moved manually, the electric motor is also rotated via a deceleration gear, and resistance working on the slide door becomes large, and the open-close operation becomes heavy. Therefore, an electromagnetic clutch is arranged between the gear deceleration mechanism and the drum, and when the slide door stops in its fully opened status or fully closed status, this electromagnetic clutch is cut off, and a manual open-close operation may be carried out.
In such an automatic open-close device, when the electromagnetic clutch is disconnected, the drum will rotate easily, accordingly, when the slide door is stopped at the intermediate position between its fully opened position and fully closed position, if the electromagnetic clutch is disconnected, in the instance when a vehicle is inclined, the slide door will open and close abruptly owing to its own weight, which is dangerous. Therefore, in one disclosed in Patent Application Laid-Open Publication No. 10-317795 Gazette, when the slide door is stopped in its intermediate position, the electromagnetic clutch is made into its connected status, thereby the slide door is prevented from abruptly opening or closing on a slope or so. However, because the electromagnetic clutch is kept at its connected status when current is supplied from a battery, if the slide door is stopped at the intermediate position for a long time, the battery burden increases, and in some cases, the battery is apt to become dead, which has been other problem with the prior art.
Meanwhile, as disclosed in Patent Application Laid-Open Publication No. 10-193978 Gazette, an automatic open-close device is known where when the slide door stops halfway, the electromagnetic clutch is controlled intermittently and the slide door is moved to the open-close end portion and the electromagnetic clutch is switched to its disconnected status. However, in this instance, when the electromagnetic clutch is connected and disconnected, abrasion of the clutch surface is facilitated, and sounds occur owing to intermittent operation of the clutch, and electric noises occur, which has been still other problem with the prior art.