TD-4 SYSTEM TECHNOLOGIES OF A DUAL CAVITY HALF-TOROIDAL CVT(TRACTION DRIVES)

KUMURA Haruyoshi, NAKANO Masaki, MORI Haruhito, SUGIHARA Jun, WATANABE Jun, USHIJIMA Kenshi

doi:10.1299/jsmeimpt.ii.01.202.838

A half-toroidal continuously variable transmission (CVT) was developed for the first time anywhere in the world for application to passenger cars equipped with a 3.0-liter turbocharged engine. This paper describes several key technologies to establish the system of Dual Cavity Half-Toroidal CVT. Important system technologies are as follows. Traction drive analysis for practical condition, synchronization of 4 power rollers, stability and response of a ratio changing. Traction drive analysis is important to design the loading force of the variator. The traction characteristics were obtained quantitatively over a wide range of conditions by using a 4-roller tester. A mathematical model was developed to calculate traction characteristics, taking into account spin and side slip. The calculated results obtained that temperature has a significant effect on traction characteristics under actual usage conditions. Synchronization of 4 power rollers is important to keep a system reliability. In the variator, the upper and lower linkages of the trunnions are both coupled longitudinally to secure sufficient stiffness and strength for perfect synchronization of 4 power rollers. Ratio change control is important to realize a excellent driveability of the vehicle. Ratio control system, which uses a servo control mechanism with ratio control cam, can realize the quick response and stability at the same time. This paper explains the ratio control system with simulation results and experimental data.

TD-4 SYSTEM TECHNOLOGIES OF A DUAL CAVITY HALF-TOROIDAL CVT(TRACTION DRIVES)

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