Planetary Gearbox with Magnetic Orbital Rollers
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Solution Overview
Problem
Existing speed change devices face challenges in achieving high torque transmission due to low coefficient of friction in common material combinations, instability in roller spacing, axial alignment, and the need for additional bearings and planet carriers, which increase complexity and cost.
Innovation Solution
A speed change device with inner and outer races, orbital rollers, and permanent magnets, where the rollers are in rolling contact and can carry gears or lobes, eliminating the need for a planet carrier by direct torque transmission and using magnetic forces to align and rotate the rollers, reducing the requirement for separate bearings and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common material combinations such as steel on steel are used, then manufacturing cost is reduced, but coefficient of friction becomes too low to enable effective camming action
Solution Approach 1:
The patent applies composite materials by combining steel rollers with nickel alloy coatings or other material combinations that provide high coefficient of friction. This allows the base structure to remain simple and manufacturable while the surface properties are enhanced to enable effective camming action and torque transmission.
2Stability of the object's composition
If a planet carrier is used to position the planets, then roller positioning is achieved, but rotational mass, cost and complexity increase
Solution Approach 1:
The patent extracts and eliminates the planet carrier component entirely. Instead of using a separate positioning structure, the rollers are directly positioned and supported by the inner and outer races, which maintain roller spacing through their geometric relationship and the camming action itself.
Solution Approach 2:
The patent merges the functions of the planet carrier into the race structures. The inner and outer races simultaneously serve as support structures, torque transmission paths, and roller positioning mechanisms, eliminating the need for a separate planet carrier component.
3Stability of the object's composition
If bearings are added to keep the outer race axially aligned with the inner race, then alignment is maintained, but device complexity and cost increase
Solution Approach 1:
The patent implements self-alignment through the camming action and geometric constraints of the roller-race interaction. The rollers naturally maintain axial alignment between the inner and outer races through the camming forces generated during torque transmission, eliminating the need for separate bearing components.
4Ease of manufacture
If circumferential spacing of rollers is not controlled, then manufacturing is simplified, but the inner race will not stay concentric with the outer race
Solution Approach 1:
The patent incorporates preliminary positioning features directly into the race structures, such as circumferential grooves or lobes, that pre-establish the correct circumferential spacing of rollers during assembly. This ensures proper concentricity is achieved without requiring complex post-assembly adjustment or control mechanisms.
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 achieves efficient torque transmission with reduced complexity and cost by ensuring equal circumferential spacing and axial alignment, eliminating the need for additional bearings and simplifying manufacturing, while providing high surface area contact for increased friction and reduced sliding, resulting in a self-energizing, low-friction gearbox.
Implementation Method 1
a permanent magnet carried by a magnet carrying inner roller of the inner rollers or a magnet carrying outer roller of the outer rollers, and a stator having electromagnetic elements for interacting with the permanent magnet to drive the orbital rollers
Implementation Method 2
inner rollers in rolling contact with the outer surface of the inner race and outer rollers in rolling contact with the inner surface of the outer race
Implementation Method 3
The inner and outer rollers may be geared and the rolling contact may be geared contact
Data Source
AI summary
A planetary gearbox with two rows of planets, at least some of the planets including magnets. The planets are driven by a stator to drive the gearbox as a motor. The planets may be geared with axial portions with different helix angle to position the gears and avoid the need for a planet carrier or bearings. Gears with small heights and/or high pressure angles may be used to avoiding or reduce negative effects of conventional gearing.