Planetary Roller Traction Drive for High-Speed Energy Transfer
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Solution Overview
Problem
Standard gearing systems are limited to rotational speeds of approximately 100,000 rpm, making it challenging to couple high-speed rotational devices with other machines and devices that operate at different rotational speeds.
Innovation Solution
A traction drive system comprising a shaft with a central traction surface, planetary rollers with traction surfaces, and a ring roller, where the planetary rollers are mounted on a carrier rotating opposite to the ring roller, allowing for the transfer of rotational mechanical energy through multiple traction interfaces, and a continuously variable traction drive with translating races and ball bearings to adjust rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If standard gearing systems are used to transfer rotational mechanical energy, then the system can operate at rotational speeds up to approximately 100,000 rpm, but the system cannot effectively couple high-speed rotational devices operating above 100,000 rpm with other machines operating at different rotational speeds
Solution Approach 1:
The patent introduces planetary rollers as intermediary elements between the input shaft and output ring gear. These planetary rollers act as mediators that can accommodate extreme speed differences by rolling along the shaft surface and driving the ring gear, enabling coupling between devices operating at vastly different rotational speeds including those exceeding 100,000 rpm.
Solution Approach 2:
The planetary rollers are designed to be movable along the shaft surface rather than fixed in position. This dynamic arrangement allows the planetary rollers to self-adjust their position and contact points based on the speed ratio requirements, providing continuous variability in the speed reduction ratio and enabling adaptation to different operational conditions.
2Speed
If highly polished and specially designed gears are used to reach high rotational speeds of approximately 100,000 rpm, then the rotational speed capability is improved, but the device complexity and manufacturing requirements increase significantly
Solution Approach 1:
The patent replaces the traditional meshing gear system with a rolling contact system using planetary rollers on a shaft surface. This substitution eliminates the need for complex high-speed gear manufacturing and polishing while achieving comparable or superior speed capabilities through the rolling motion of the planetary rollers against the shaft and ring gear.
Solution Approach 2:
The power transmission function is segmented into multiple planetary rollers distributed around the shaft, each independently contacting the shaft surface and driving the ring gear. This segmentation distributes the mechanical stresses and allows simpler individual roller components rather than requiring a single complex high-speed gear system.
3Device complexity
If a fixed gear ratio system is used, then the mechanical coupling is simple, but the system cannot provide continuously variable speed adjustment from 0% to 30% of input speed
Solution Approach 1:
The planetary rollers are designed with the capability to move axially along the shaft surface, creating variable contact radii. This dynamic positioning allows continuous adjustment of the effective gear ratio, enabling speed reduction ratios that can be varied continuously from 0% to 30% of the input speed while maintaining a relatively simple mechanical structure.
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
Enables efficient transfer of high-speed rotational energy across a wide range of speeds, from 0% to 30% of the input speed, effectively overcoming the limitations of standard gearing systems by providing a flexible and adjustable mechanism for coupling high-speed devices.
Implementation Method 1
a first plurality of traction interfaces exist between the plurality of planetary roller traction surfaces and the shaft traction surface
Implementation Method 2
a plurality of traction ball bearings disposed between the first race, the second race, the third race and the fourth race
Data Source
AI summary
A fixed ratio traction drive is disclosed that uses multidiameter planet rollers. The high speed traction drive provides speed reduction from a high speed shaft. A planet carrier is used to rotationally mount the multidiameter rollers. A continuously variable transmission that uses planetary ball traction is also disclosed that provides infinitely variable speed ratios.