Nutating Electric Motor With Dynamic Air Gap for High Torque Density
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Solution Overview
Problem
Conventional electric motors face challenges in achieving high torque density due to the difficulty in harnessing radial pressure effectively, leading to inefficiencies in power transmission.
Innovation Solution
The design incorporates a rotor-stator configuration with a nutating traction interface and dynamic air gap, where the rotor nutates with respect to the stator, allowing for the radial magnetic field to generate torque, and features multiple windings and lubrication systems to enhance torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electric motors use balanced radial pressure to prevent stator-rotor collisions, then reliability is improved, but torque density deteriorates because the normal force cannot be harnessed for torque generation
Solution Approach 1:
The patent inverts the conventional approach by allowing unbalanced radial pressure to act on the rotor, converting the normally harmful radial force into a useful torque-generating force. The rotor is deliberately designed to experience net radial pressure that produces torque rather than being perfectly balanced to prevent contact.
Solution Approach 2:
The patent introduces a fluid medium (liquid or gas) between the stator and rotor that transmits the radial pressure force while preventing direct mechanical contact. This intermediary allows the radial force to be harnessed for torque generation without causing stator-rotor collisions.
2Power
If electric motors attempt to harness normal force through eccentric rotor motion, then torque density is improved, but power transmission smoothness deteriorates
Solution Approach 1:
The fluid intermediary smooths out the power transmission by absorbing and distributing the forces generated by eccentric rotor motion. The fluid acts as a cushion that maintains continuous force transmission while reducing vibrations and irregularities.
Solution Approach 2:
The patent employs hydraulic or pneumatic principles by using pressurized fluid to transmit force between the rotor and stator. The fluid pressure distribution is controlled to maintain smooth torque transmission while enabling the rotor to operate in an eccentric position for high torque density.
3Manufacturing precision
If conventional motors maintain a fixed air gap between stator and rotor, then manufacturing precision is improved, but torque generation efficiency deteriorates because radial pressure cannot be effectively utilized
Solution Approach 1:
The patent transitions from a static fixed air gap to a dynamic variable air gap configuration. The air gap is allowed to vary during operation to optimize torque generation while maintaining sufficient clearance. The fluid intermediary compensates for the variable gap, ensuring consistent force transmission.
Solution Approach 2:
The patent changes the air gap parameter from a fixed dimensional value to a dynamically adjustable parameter. The air gap distance is optimized during operation to maximize radial pressure utilization for torque generation, with the fluid intermediary maintaining reliable force transmission across the varying gap.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables high torque density and smooth power transmission by effectively utilizing radial pressure, reducing traditional trade-offs between normal and tangential forces.
Implementation Method 1
a magnetic field is produced by electrical activation of the motor to generate a force between the rotor and the stator
Implementation Method 2
The stator and/or the rotor is electrically activated to produce a tangential magnetic force that generates a torque
Data Source
AI summary
An electric motor has a stator mechanically coupled to the rotor by a nutating traction interface, such that during nutation of the rotor with respect to the stator a tilt axis of the rotor progresses about the axis of rotation of the output shaft. The rotor and a surface of the stator bound a dynamic gap across which a magnetic field is produced by electrical activation of the motor to generate a force between the rotor and the stator. The traction interface and the gap are arranged such that, in a plane containing the axis of rotation of the output shaft, the traction interface is angled with respect to the stator surface bounding the gap. The rotor is connected to the output shaft by a tiltable connection such as a gimbal.