Modulatable power transmission clutch and a marine transmission

摘要

A modulatable power transmission clutch including interleaved clutch plates and having a central power transmitting shaft extending axially through the clutch. The clutch includes a fluid operated movable piston for effecting clutch operation by compression of the plates. The piston has a smaller piston area and a larger piston area, the smaller piston area has fluid flow directed to it a variable fluid pressure whereby the clutch is modulatable. The larger piston area is adapted to have fluid flow directed thereto to effect maximum and unmodulatable engagement of the clutch. A spring loaded normally closed trigger valve controls fluid flow to the larger piston area in response to fluid pressure above a predetermined amount at the smaller piston area. The trigger valve is mounted in the shaft and is normally closed so that pressure fluid is directed to the smaller piston area at a variable fluid pressure whereby the clutch is modulatable. When the valve is open by said fluid pressure over a predetermined amount, the valve permits fluid flow to the larger piston area to effect maximum and unmodulatable engagement of the clutch for full clutch capacity.