1991-11-01

Shiftability and Shift Quality Issues in Clutch-Transmission Systems 912697

With synchronized transmissions, the problem of shift effort and corresponding shift time are complex ones. They deal with the proper function of both the clutch and transmission within the total drivetrain system, cnd relate to the dynamic behavior of this system.The present paper represents an engineering effort of rigorously defining clutch and transmission compatibility with respect to shift quality. A technically realistic, analytical description of shiftability for synchronized transmissions and corresponding design limitations for the clutch-transmission system are the specijic objectives of this paper. Design recommendations based on the modeling introduced in this paper point out a significant clutch contribution to shifting problems and the importance of the system approach itself.The mathematical model describing shift and synchronizing processes is analyzed to determine shift quality, clutch quality and transmission quality with respect to shifting. These three quality definitions are introduced to study the system performance and determine engineering compatibility criteria for system components. The clutch-transmission selection formula is derived and shifability for both upshifts and downshifts is studied. Some numerical examples are covered to demonstrate how the proposed approach works in specific applications.

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