Control device for a transmission with an infinitely variable transmission ratio are designed with an electromagnet powder coupling.

摘要

A belt-drive infinitely variable transmission is connected to a crankshaft of an engine through an electromagnetic powder clutch (1). The current to the clutch coil (8) is controlled by a control system (41) having an engine speed signal producing circuit (48, 49), a vehicle speed signal producing circuit (52, 53) and an arithmetic circuit (50) which controls the clutch current flowing through the clutch coil (8) in dependency on the engine speed signal and vehicle speed signal. The arithmetic circuit (50) operates to cut off the clutch current when the engine speed decreases to a predetermined value which is slightly higher than the engine stalling speed during shiftdown operation of the transmission.