Abstract
With certain simplifying assumptions, the validity of which is examined, the elementary differential equations relating synchronizing torque, time, and inertias are set up and solved. The effect of variation in the controllable variables is considered, and it is shown that the principal factor is the rotational inertia of the parts between the clutch and the synchronizer. The heat rating of synchronizers is discussed.
The effect of scale is next considered, and it is shown that it is absolutely more difficult to effect synchronous gear-changing on larger vehicles.
A coefficient of friction at the synchronizer varying linearly with slip speed is chosen as a first approximation to variable friction, and the corresponding differential equations are set up and solved. The crash gearbox without synchronizers is discussed.
Failure to effect a synchronous change by crashing through is considered for baulked synchronizers and the equations of equilibrium are obtained. Failure to effect a change due to loss of way from too slow a change is also examined.
The performance of the synchronizers of an automobile gearbox is calculated and the results obtained by the variable or constant friction methods are shown to be of the same order; both agree satisfactorily with test results. The predicted effectiveness of baulk also agrees with trial results. Similar calculations are made for the German Panther tank gearbox and the phenomenon of the unsatisfactory change from second to third gear proven on test is predicted.
Finally, the application of the foregoing methods to easy-change gearboxes other than synchromesh is mentioned.
The use of similar methods with main engine clutches is discussed in Appendix I.
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