Nested Gear Trains with Resilient Backlash Take-Up
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Solution Overview
Problem
Conventional nested gear trains face limitations in maximum transmissible torque due to inefficiencies and machining challenges, particularly with tooth alignment and grinding accuracy, which affect load distribution and torque capacity.
Innovation Solution
The design incorporates two coaxial rings with identical annular segments and planets that engage both rings and the sun gear, allowing for grinding of single toothed segments and incorporating a resilient backlash take-up device to eliminate backlash, enhancing torque transmission and machining precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If machining toothed segments by cutting is used, then manufacturing process is simpler, but machining accuracy and load distribution balance deteriorate due to alignment difficulties and large groove requirements
Solution Approach 1:
The patent replaces the cutting machining method with a grinding method for manufacturing toothed segments. Grinding allows for much higher precision in tooth alignment and surface finish, eliminating the alignment difficulties and large groove requirements associated with cutting. This substitution directly resolves the contradiction by sacrificing some manufacturing simplicity to gain significant improvements in machining accuracy and load distribution.
2Force
If the number of planets is increased to raise maximum transmissible torque, then torque capacity improves, but device complexity and machining difficulty increase
Solution Approach 1:
The patent divides the gear train into two independent nested gear trains, each with its own set of planets engaging with different rings. This segmentation allows each subset of planets to be optimized independently, reducing the overall complexity compared to a single large system with many planets. The segmentation principle enables torque multiplication while maintaining manageable device complexity through modular organization.
Solution Approach 2:
The patent employs a nested configuration where one gear train is positioned inside another, with planets from the first train engaging with the first ring and planets from the second train engaging with the second ring. This nesting allows multiple planet gears to be arranged in a compact space, increasing the effective number of load-bearing planets without proportionally increasing the overall device size or complexity. The nested structure efficiently packs more planets into the available space.
3Area of stationary object
If conventional epicyclic gear train configuration is used, then transverse size is limited, but maximum transmissible torque is limited by the number of planets that can be engaged
Solution Approach 1:
The patent uses a nested configuration where one complete gear train (sun gear, planets, ring) is placed inside another gear train. This nesting allows the system to accommodate more planets and gear elements within the same transverse envelope, effectively increasing the maximum transmissible torque without increasing the overall device size. The nested structure efficiently utilizes the available space by stacking gear trains in concentric arrangements.
Solution Approach 2:
The patent transitions from a two-dimensional arrangement of planets around a single sun gear to a three-dimensional nested configuration with multiple levels of gear trains. By adding the radial dimension through nesting, the system can engage more planets simultaneously within the same transverse footprint, thereby increasing torque capacity without expanding the device's external dimensions.
Data Source
AI summary
A gear device, wherein it comprises at least: a shaft provided with a sun gear; at least two coaxial rings with internal teeth, namely at least one first ring and at least one second ring having at least one first annular segment and at least one second annular segment; and planets engaging with the sun gear, the first ring, and the segments of the second ring, which segments mesh with a particular toothed relationship.