Cycloid Speed Reducer Structure for High Ratio and Easier Machining

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Solution Overview

Problem

Conventional RV reducers have high volume, weight, and cost, while harmonic drive reducers face issues with low rigidity, high impact resistance, and limited reduction ratio, and cycloid speed reducers face challenges in machining teeth.

Innovation Solution

A cycloid speed reducer design incorporating an eccentric wheel, first and second wheel assemblies with rollers and teeth configurations, allowing for high reduction ratios and easier machining of teeth, while reducing volume and weight and enhancing rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional RV reducer is used to achieve high reduction ratio, then the reduction ratio is improved, but the volume and weight increase and cost becomes high

Engineering Contradiction:

Improvereduction ratioVSAvoidvolume

Core Design Contradiction:

ProductivityVSVolume of moving object

Solution Approach 1:

The patent combines the eccentric mechanism with cycloid wheel engagement in a single integrated structure, merging the functions of speed reduction and motion transformation into one compact mechanism rather than using separate gear stages, thereby achieving high reduction ratio in a reduced volume

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cycloid wheels are positioned within the eccentric mechanism structure, with the rotating wheel containing cycloid wheels nested inside the housing that includes eccentric mechanism, creating a compact nested arrangement that reduces overall volume while maintaining high reduction ratio

Inventive Principle:

Principle #7Nested doll (Nesting)

2Volume of moving object

If a harmonic drive reducer is used to reduce volume and weight, then the volume and weight are reduced, but the rigidity decreases and impact resistance becomes poor

Engineering Contradiction:

ImprovevolumeVSAvoidrigidity

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent uses metallic material for the cycloid wheels and eccentric mechanism components, providing localized high rigidity and impact resistance at critical load-bearing points, while the overall structure remains compact like harmonic drives

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs metallic materials for the cycloid wheels and housing components, combining the strength and rigidity of metal with the compact design, creating a composite structure that achieves both reduced volume and enhanced strength compared to pure flexible element designs

Inventive Principle:

Principle #40Composite materials

3Productivity

If conventional cycloid speed reducer design is used to achieve high reduction ratio, then the reduction ratio is improved, but the machining difficulty of teeth increases

Engineering Contradiction:

Improvereduction ratioVSAvoidmachining difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

Instead of forming concave structures and machining inner teeth as in conventional designs, the patent forms convex teeth on the outer periphery of the rotating wheel, inverting the traditional approach and making the teeth much easier to machine using standard external gear machining processes

Inventive Principle:

Principle #13The other way round (Inversion)

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 new design achieves high reduction ratios, easier assembly, reduced cost, increased rigidity, and prolonged lifespan, combining the benefits of RV and harmonic drive reducers with improved machining capabilities.

Implementation Method 1

The at least one first roller is disposed on the inner wall. The at least one second roller is disposed within the concave structure. Each of the at least one first roller is in contact with the corresponding at least one first tooth. Each of the at least one second roller is in contact with the corresponding at least one second tooth

Methodology Applied

Scientific EffectRolling contact: Roller

Data Source

PatentUS12359711B2Speed reducer

Publication Date: 2025.07.15 DELTA ELECTRONICS INC(CN)

AI summary

A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.