Planetary Gear Drive for Compact High-Ratio Counter-Rotation

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Solution Overview

Problem

Existing gear drives face challenges in achieving large gear ratios in compact sizes, which limits their application in smaller spaces.

Innovation Solution

The implementation of a gear drive system that includes a first and second planetary gear set, where the first carrier of the first planetary gear set is coupled to a gear of the second planetary gear set, allowing for counter-rotating outputs from a single input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional gear drives are used to achieve large gear ratios, then the gear ratio is increased, but the device size increases

Engineering Contradiction:

Improvegear ratioVSAvoiddevice size

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The patent employs nested planetary gear sets where smaller planetary gear sets are positioned within or around larger ones, allowing multiple gear reduction stages to be compacted into a single integrated structure. This nesting arrangement achieves large overall gear ratios while maintaining a compact footprint, directly resolving the contradiction between gear ratio and device size.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from linear/sequential gear arrangements to a radial/dimensional configuration using planetary gear sets. By arranging gears in multiple radial dimensions around a central sun gear, the system achieves high gear ratios in a compact cylindrical volume, effectively utilizing three-dimensional space rather than extending linearly.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple planetary gear sets are used to achieve counter-rotating outputs, then the functionality is improved, but the device complexity increases

Engineering Contradiction:

Improvecounter-rotating output capabilityVSAvoidnumber of planetary gear sets

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple planetary gear sets into a single integrated assembly where carriers, planet gears, and sun gears of different stages are mechanically coupled. This consolidation achieves counter-rotating outputs while reducing the number of separate discrete gear sets, thereby improving versatility without proportionally increasing complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear sets are designed with universal components that serve multiple functions: planet gears simultaneously engage with both sun gears and ring gears, carriers transmit motion to multiple outputs, and the same basic structure produces both same-direction and opposite-direction outputs. This multi-functionality reduces overall system complexity while achieving versatile counter-rotating output capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12292098B2Rotating gear drive and associated systems, components, and methods

Publication Date: 2025.05.06 GIG ENERGY LLC

AI summary

A gear drive includes a first rotational input coupled to a first planetary gear set. The gear drive further includes a second planetary gear set rotationally coupled to the first planetary gear set. The gear drive also includes a second sun gear of the second planetary gear set coupled to a first output. The gear drive further includes a second ring gear of the second planetary gear set coupled to a second output.