Research On Engaging Property Of High Speed Sprag Overrunning Clutch

The Positive-continous-engagement(short as PCE) overunning clutch is the keypower transmission component which located between the helicopter’s engine andmain reducer,it’s failure will lead to the interruption of powertrain. The roll overfailure is easily happen under high speed and impact load during engagement.Thehelicopter’s maneuvering flight performance was directly affected by the cluth’sengagement property.It’s necessary to carry out research on the dynamicalengagement properties of the overrunning clutch. In this paper,measured by theengagement time and impact load,carried research on the engagement propertiesby building the parameterized clutch model:Based on the vector analysis and dynamics theory,taking the sprag,inner andouter shaft’s contact and construction deflection into account, The contact-collisionmodel which between the sprag with the shafts and container is built Thepenetration depth during any time of the simulation was compuated.The contactforce and the dumping force were take into the clutch’s dynamic model based on theHertz contact theory.The contact force between the sprag with container,sprag withthe inner and outer shaft are calculated based on the Hertz contact theory.The parameterized model of clutch was built in ADAMS. The engae anlge atthe initial contact status and the engaged status is conducted.The user’s subroutineabout contact force,friction and collision detection which written by Fortran waslinked to ADAMS/Solver as.dll file to solve the dynamical clutch model.The influence of different transition arc radius and the worn of contact area tothe engagement performance is Analysised.The clutch’s pop-in and outphenomenon is Simulated and the reason is discussed.