6-39. REVERSE GEAR ASSEMBLY.
The torqmatic marine reverse gear used on multiple engine units shown below, along with the flywheel assembly
provide an emergency forward clutch lock, positive clutch engagement or release by simply moving the selector valve
lever to the desired position for forward, neutral or reverse.
Each marine gear consists of a flywheel and forward drive clutch assembly, and a reverse drive clutch assembly
with a through drive shaft. Also, each has an oil pump (refer to paragraph 3-40) for supplying oil under pressure for
operating the forward and reverse clutches, a control valve (refer to paragraph 2-32) to admit oil to the clutches, an oil
strainer, a full-flow oil filter and an oil cooler.
Power from the diesel engine is imparted to the through drive shaft by locking the forward or reverse clutch plate
between the hydraulically operated piston and a drive plate.
Each flywheel consists of a flywheel (1), ring gear (2), forward clutch plate (3), forward clutch drive plate (4),
forward clutch piston (5) and a forward clutch piston type dump valve.
The flywheel, with the ring gear installed, is bolted directly to the crankshaft. The forward clutch drive plate is
bolted to the aft face of the flywheel. This plate also serves as a drive for the reverse planetary gear set since the gear
teeth at the inner diameter mesh with the teeth of the sun gear.
The forward clutch piston rides in the flywheel and is driven by three clutch drive pins anchored in the flywheel.
Movement of the piston is obtained by admitting oil under pressure into the cavity between the flywheel and the forward
face of the piston. Oil leakage from this cavity is prevented by seal rings and expanders at the inner and outer diameters
of the piston. When the oil pressure is released, a series of springs within the forward clutch drive plate move the piston
Facings on the forward clutch plate (3) are sandwiched between the drive plate (4) and the forward piston (5)
while splines at the clutch plate hub engage mating splines on the through drive shaft. When the facings on the clutch
plate are locked between the piston and the drive plate by movement of the piston, the clutch plate and the shaft are
driven in a forward direction.