Patent ID: 6915888

Claim:
An external control type fan-coupling device comprising a housing having a case made of a non-magnetic material and a cover mounted on said case, said housing being borne through a bearing on a rotary shaft, a partition in said housing and dividing said housing into an oil sump and torque transmission chamber, an oil feed adjusting hole formed through said partition for providing communication between said oil sump and said torque transmission chamber, an oil recovering circulation passage extending from an outer circumferential position in said torque transmission chamber to said oil sump, a dam in the torque transmission chamber near the oil recovering circulation passage, a drive disk secured to an end of the rotary shaft and disposed in the torque transmission chamber, a valve member having a magnetism and disposed for selectively opening and closing the oil feed adjusting hole in the partition, an electromagnet supported on the rotary shaft through a bearing and substantially opposed to the oil sump, said electromagnet operating the valve member for selectively opening, closing and controlling the oil feed adjusting hole for controlling a flow of oil into the torque transmission chamber for controlling torque transmission from the drive disk to the housing, and a magnetic member assembled to the housing between the electromagnet and the valve member for transmitting magnetic flux of the electromagnet to the valve member, wherein said magnetic member is an integral structure having a plurality of arcuate holes in a plate member and sealed by filling said arcuate holes with a sealant.