| 摘要 |
A friction clutch for a motor vehicle includes a cover, a pressure plate, a biasing member and an adjustment mechanism. The adjustment mechanism includes a first annular cam, a second annular cam and a torsional spring and housing assembly. The cover has an axis of rotation. The pressure plate is coupled to the cover for rotation therewith about the axis. The pressure plate has a frictional engagement surface substantially normal to the axis. The pressure plate has a plurality of cooling blades extending from the pressure plate on a side opposite the frictional engagement surface. The blades are located at a first radial distance from the axis. The biasing member is interposed between the cover and the pressure plate, and biases the pressure plate toward an engaged pressure plate position. The adjustment mechanism is centered about the axis and is located at a first radial distance from the axis. The adjustment mechanism is operably disposed between the biasing member and the pressure plate. The first annular cam is rotatably fixed with respect to the pressure plate. The second annular cam is rotatable relative to the first annular cam. Both cams have a plurality of mutually engaged cam surfaces configured such that rotation of the second cam relative to the first cam in a first direct increases a height of the adjustment mechanism. The torsional spring and housing assembly is operably disposed between the first annular cam and the second annular cam, and includes a torsional spring and a housing. The housing receives the torsional spring. The housing has a flange. The flange is disposed over the blades of the pressure plate, thereby defining radially extending air flow channels. The pressure plate and the housing together define an impeller fan which forces air radially outwardly past the pressure plate with rotation of the pressure plate about the axis.
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