High Torque, Direct Drive Electric Motor

Bear Engineering proposes to develop an innovative high torque, low speed, direct drive motor in order to meet NASA's requirements for such devices. Fundamentally, all electric motors basically work on the same electromagnetic principle: a tangential electromagnetic force attracts the rotor to the stator. Just when the rotor field is closest to the stator field and the electromagnetic attraction is greatest, the power is interrupted and another set of magnetic poles repeats the cycle. Furthermore, the two magnetically attracted elements never make contact, which would otherwise offer the highest force of attraction. The proposed novel motor design operates and behaves entirely differently from all other known electric motor designs and it will produce incredibly high, direct drive torques at low rotational speeds. Its operational performance is similar to that of a stepper motor with a 1000:1 gearhead attached, but the similarity ends there. The motor is configured such that its length to diameter aspect ratio is opposite that of traditional motors as it has a relatively large diameter and short axial length; this offers all new packaging opportunities. The proposed design also allows for a single, large diameter bearing pair to be used for the motor's output shaft which renders it stiff enough to directly mount the driven elements. The need for additional bearing supports and bearing mounting structure is thus eliminated. At the end of the proposed Phase 1 effort, the motor design will be at TRL 4 and by the end of a potential Phase 2, the system will be at TRL 6. More »