Strain Wave Gear Encoder Mounting for Compact Precise Assembly

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Solution Overview

Problem

Conventional strain wave gears for robot arms suffer from imprecise encoder attachment, leading to potential misalignment and increased assembly time, which affects the precision and accuracy of the transmission system.

Innovation Solution

The strain wave gear design integrates the encoder arrangement between support and gear elements, ensuring precise alignment and reducing the risk of misalignment, with the encoder track and reader being fastened between specific elements to enhance accuracy and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the encoder track and reader are attached externally on/near the gear or in a housing/cabinet, then the assembly process is simpler, but the alignment precision and measurement accuracy deteriorate due to potential misalignment and strain on the track

Engineering Contradiction:
Improveencoder attachment processVSAvoidencoder measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The encoder track is integrated directly with the gear element, merging two previously separate components (encoder track and gear) into a single unified structure. This eliminates the need for separate attachment processes and ensures precise alignment between the encoder track and gear, resolving the contradiction between ease of manufacture and measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If the encoder track and reader are attached as separate steps in conventional solutions, then the assembly process is more flexible, but the assembly time increases and precision is reduced

Engineering Contradiction:
Improveassembly process flexibilityVSAvoidassembly time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The encoder track and gear element are manufactured as a single integrated component, eliminating multiple assembly steps. This merging of components reduces assembly time while maintaining the flexibility to attach the integrated unit as a single piece, thus resolving the contradiction between adaptability and time loss.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the encoder arrangement is attached externally, then the gear design remains simple, but the overall system becomes larger and less compact

Engineering Contradiction:
Improvegear design simplicityVSAvoidsystem compactness
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The encoder track is nested directly onto the gear element, with the encoder reader positioned to read the track while both components occupy the same radial space. This nesting arrangement eliminates the need for external mounting space, making the system more compact while keeping the gear design relatively simple.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4063693A1Strain wave gear with encoder integration
Publication Date: 2022.09.28 UNIVERSAL ROBOT
  • EP4063693A1 patent drawingFigure 1~2
  • EP4063693A1 patent drawingFigure 3~6
  • EP4063693A1 patent drawingFigure 7~8

AI summary

The invention relates to a strain wave gear comprising: gear elements, wherein said gear elements comprises a circular element with an internally toothed gear and wherein said gear elements comprises a flex element with a flexible externally toothed gear arranged in said circular element; a wave generator rotatably arranged in said flex element and configured to flex said externally toothed gear in a radial direction to partly mesh said internally toothed gear and said externally toothed gear; support elements comprising a bearing input support element and a bearing output support element rotatably coupled to said bearing input support element, wherein elements of said support elements are fixed respectively to elements of said gear elements; and an encoder arrangement comprising an encoder track and an encoder reader, wherein a part of said encoder arrangement is fastened between an element of said support elements and an element of said gear elements.