Planetary Gear Interconnection for Compact Variable Transmission Ratios
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Solution Overview
Problem
Existing mechanical interconnection of multiple rotatable devices (MIMRDs) face limitations such as complexity, lack of compactness, efficiency, and restricted transmission ratios, particularly in applications requiring high torques and variable transmission ratios.
Innovation Solution
A MIMRD design comprising quasi-duplicated planetary gear train systems with differential gain-K ranging between 0.7 and 1.4, incorporating first and second stages with torque resisting or controlling means, allowing for flexible and seamless variation of transmission ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional mechanical transmissions are used to achieve high transmission ratios, then the transmission ratio is increased, but the device complexity and size increase significantly
Solution Approach 1:
The patent merges multiple planetary gear sets into a single integrated mechanism where gear sets are coupled through shared planet carriers and sun gears. This combination allows achieving high transmission ratios (up to 10:1 or higher) without requiring multiple separate gear stages, thereby reducing overall device complexity while maintaining adaptability in transmission ratio.
Solution Approach 2:
The planetary gear mechanism is designed to serve multiple functions: it can operate in different transmission ratio modes, provide torque multiplication, and accommodate variable speed requirements. The same basic structure achieves both high transmission ratio and compact form factor, making the device versatile for applications ranging from prosthetics to power transmission systems.
2Adaptability or versatility
If conventional mechanical transmissions are used to achieve high transmission ratios, then the transmission ratio is increased, but the device size increases
Solution Approach 1:
The planetary gear sets are nested within each other with shared components - inner planet carriers are positioned within outer gear sets, and sun gears of one stage serve as planet carriers for another stage. This nesting arrangement achieves high transmission ratios in a compact volume, reducing the overall size of the transmission device while maintaining the required gear ratio range.
3Device complexity
If conventional mechanical transmissions are used, then structural simplicity is maintained, but efficiency and torque transmission capability are limited
Solution Approach 1:
The patent implements a dynamic planetary gear mechanism where the planet carriers can rotate independently and the gear sets can engage/disengage based on operational requirements. This dynamic configuration optimizes torque distribution across multiple planet gears, reducing stress on individual components and minimizing energy loss through friction and deformation, thereby improving transmission efficiency.
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
The design achieves high transmission ratios in a compact form with enhanced efficiency, enabling applications in diverse domains like prostheses, robotics, and power transmission systems.
Implementation Method 1
a gear train for transmitting or interchanging speed and/or torque between the rotatable devices
Data Source
AI summary
Mechanical interconnection of multiple rotatable devices that includes: a gear train, at least three rotatable devices, one or more first stages, and one or more second stages, a first element, i.e. a geared element or a planet carrier, of one of the second stages forming a torque resisting means being blocked or impeded in a controllable way. The third rotatable device interacting with a second element, i.e. a gearwheel, or a planet carrier, of one of the second stages.