| 摘要 |
<p>A fan drive assembly includes a viscous coupling device (11), a radiator cooling fan (F), and a speed increasing mechanism (13), so that, at relatively low engine speeds, the fan (F) is driven at a speed ("overdrive") greater than the input speed to the coupling device (11), and at relatively higher engine speeds, the input torque is transmitted through the viscous coupling in the normal manner. In the subject embodiment, the speed increasing mechanism (13) is a planetary gear set, in which torque is transmitted from the input shaft (21) to the planet carrier (47), and in the overdrive condition, the sun gear (53) is grounded. The output of the planetary is the ring gear (59), which directly drives a housing (61) attached to both the housing (17) of the viscous coupling, as well as the cooling fan (F), thus effectively bypassing the viscous clutching action. <IMAGE></p> |
