Patent ID: 7367438

Claim:
An external-control-type fan coupling device being configured such that an inside of a hermetic housing which is formed of a non-magnetic casing which is supported on a rotary shaft body which fixedly mounts a drive disc on a distal end thereof by way of a bearing and a cover which is mounted on the casing is divided into an oil reservoir chamber and a torque transmission chamber which houses the drive disc therein by a partition plate which is mounted on the cover, the coupling device includes an oil circulation flow passage which is formed between the torque transmission chamber and the oil reservoir chamber and an oil supply adjustment hole which is formed in the partition plate, the coupling device includes a valve element which opens or closes the oils supply adjustment hole in the oil reservoir chamber, and an open/close control of the oil circulation flow passage is performed by operating the valve element using an actuator, and the rotational torque transmission from a drive side to a driven side is controlled by increasing or-decreasing an effective contact area of oil in a torque transmission gap portion defined between the drive side and the driven side, wherein the actuator is mounted on the cover of the hermetic housing, the coupling device includes a primary coil which is fixed to the outside and a secondary coil which is fixed to the hermetic housing and faces the primary coil in an opposed manner, and the actuator which is mounted on the cover of the hermetic housing is driven by an electric current induced to the secondary coil.