Development and evaluation of a passively operating non-contact, load-responsive transmission

A previously developed passively operating transmission capable of switching its reduction ratio in response to load torque was further developed into a non-contact load-responsive transmission. The reduction ratio is switched by a non-contact magnetic clutch that responds to the load torque using a passive magnetic mechanism without any accessory actuators, sensors, electronics or power supplies. The absence of mechanical friction at the non-contact magnetic clutch resolves the problems concerning the wear and maintenance, shock while switching the clutch is greatly reduced and the actuator is protected from overloads by slippage at the magnetic clutch. This non-contact load-responsive transmission reduces the power, size and weight of the mechanical system and improves its safety and agility since a variant load can be actuated efficiently using a minimal actuator. This paper describes the structure and the operation of the non-contact load-responsive transmission and reports on the characteristics of an experimentally evaluated prototype transmission.