Development History of the Patented Variable Torque Motor - Next Step

Patents:

Two patents have been issued for this application to co-inventors Larry Zepp and Jerry Medlin. Five foreign patents have also been issued. An additional wheel motor patent describing this magnetic field weakening concept with an external magnet rotor has also been issued.  Additional US and foreign patent applications on hybrid applications of this technology are pending.

Design Concept:

Our design choice weakened the magnetic field by pushing the rotating magnet rotor out of the stator coils, thus decoupling a portion of the magnets. This design reduced magnetic strength and allowed higher speeds while Horse Power remained constant. Variations of magnet strength produced a family of motor performance curves that are functionally equivalent to a continuously variable transmission contained inside the motor.

Reliability:

To ensure mechanical reliability when the motor shifted, we incorporated two mature automotive technologies: (1) "CV" joints found in axles (2) clutch release lever found in manual transmissions. The design and mechanical shifting components also ensure the motor can operate if there is a failure in some of the electronics. If there is an interruption to power, the motor locks into place and vehicle continues to operate. This avoids the problem of zero-speed "slamming" on some other systems where higher rpm's are generated through electronic manipulation.