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(11) | EP 2 000 644 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Variable speed fan drive |
| (57) The invention relates to a variable speed fan drive (10) . There is a need for a
variable speed fan drive (10) with fewer seals and bearings, which is operated by
system hydraulic pressure, which has fewer parts and which is simpler to assemble.
A variable speed fan drive (10) is provided for a vehicle powered by an internal combustion
engine. The fan drive has a driver variable sheave unit (12), a driven variable sheave
unit (14) and a belt (69) engaging both the driver and driven variable sheave units
(12, 14). The driver variable sheave unit (12) includes a driver shaft (24) drivingly
coupled to an engine output shaft (16), a first axially fixed half sheave (30) mounted
for rotation with the driver shaft (24), and a first axially movable half sheave (40)
member mounted for rotation with the driver shaft (24) and movable axially on the
driver shaft (40). The first axially movable half sheave member (30) includes a belt
engaging flange (44) formed integrally with an axially movable piston member mounted
for rotation with the driver shaft (24) and movable axially in response to hydraulic
pressure.
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