Robot Link Structure With Internal Actuator for Positioning Accuracy

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Solution Overview

Problem

Existing robots exhibit unevenness in appearance and compromised positioning accuracy due to structural constraints and actuator placement.

Innovation Solution

A robot design featuring a first link with an internal space and an opening to accommodate an actuator, coupled with a seal between sub-links to enhance structural integration and reduce unevenness, while maintaining positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the actuator is accommodated in the first link with the second link structured to sandwich the actuator, then the appearance unevenness is reduced, but the positioning accuracy may be affected by constraints on the second sub-link

Engineering Contradiction:
Improveappearance unevennessVSAvoidpositioning accuracy
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The second link is divided into two sub-links (first sub-link and second sub-link) that sandwich the actuator. This segmentation allows the actuator to be accommodated within the link structure, reducing appearance unevenness while maintaining positioning accuracy through the specific configuration where the second sub-link is not constrained from the first link in directions crossing the rotation axis.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the second sub-link is constrained from the first link in directions crossing the rotation axis, then the structural stability is improved, but the positioning accuracy deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidpositioning accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The constraint relationship between the first sub-link and second sub-link is designed with local quality differentiation: the second sub-link is not constrained from the first link in directions crossing the rotation axis, which minimizes its influence on positioning accuracy. This selective constraint approach maintains structural stability where needed while preserving positioning accuracy in critical directions.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4559634B1robot
Publication Date: 2026.05.20 YASKAWA DENKI KK
  • EP4559634B1 patent drawingFigure 1
  • EP4559634B1 patent drawingFigure 2
  • EP4559634B1 patent drawingFigure 3

AI summary

A robot includes a first link, a second link aligned with the first link along a rotation axis and extending away from the rotation axis, and an actuator accommodated in the first link to rotate the second link around the rotation axis with respect to the first link. The second link includes a first sub-link and a second sub-link that sandwich the actuator along the rotation axis, the first sub-link is attached to the actuator, and the second sub-link is attached to the first sub-link in a state where the second sub-link is not constrained from the first link in a direction crossing the rotation axis.