TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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b. Fan Drive and Clutch (figs. 1-13 and 1-14). The fan clutch is oil cooled. The fan clutch drive and driven disks are loaded by the centrifugal action of clutch balls and springs housed in the clutch assembly. The balls and springs are in the driven member and apply upward force to the clutch disks. The clutch oil enters the fan drive vertical shaft from the fan drive housing through an annular groove in the shaft. The oil flows through a central hole in the shaft to a distributor where it is dispersed to the ball bearings and to the clutch disks. The oil moves between the clutch disks by centrifugal action and drains back through the fan drive housing into the engine oil pan. Early cooling fan clutch- es had a hydraulic disengagement feature, The clutch actuating piston (fig. 1-13) for this hydraulic disengagement feature was eliminated on late engines, and the clutch has been greatly simplified and improved (fig. 1-14). Figure 1-14. Mechanical cooling fan clutch—sectional view. 1-19