Compact Robot Arm Housing With Enlarged Tip Bore for Member Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional robotic arms face challenges in downsizing due to the difficulty in reducing the diameter of fixing members, leading to acute bending of elongated members which can cause damage, and there is a need to reduce the size of the cylindrical housing while minimizing damage to these members.

Innovation Solution

The robotic arm design includes a cylindrical housing with an inner diameter that is larger at the tip-end part than the base-end part, featuring an inner-diameter enlarged part between joint shafts, allowing elongated members to gently bend and be fixed without acute bending, thus enabling size reduction while preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the cylindrical housing is downsized to reduce robotic arm size, then the overall dimensions are reduced, but the elongated members acutely bend outwardly causing damage

Engineering Contradiction:
Improverobotic arm sizeVSAvoidelongated member integrity
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The cylindrical housing is designed with non-uniform wall thickness: the first wall thickness at the tip end is greater than the second wall thickness at the base end. This local variation in structural properties allows the housing to accommodate the bending of elongated members near the tip end while maintaining overall compactness, thus resolving the contradiction between downsizing and preventing member damage

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent addresses the radial bending problem by introducing an axial dimension solution through variable wall thickness along the axial direction of the cylindrical housing. This transforms the problem from a radial space constraint to an axial distribution of structural properties, allowing the housing to protect elongated members without increasing overall radial dimensions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the fixing member diameter is reduced to downsize the attaching structure, then the attaching structure becomes more compact, but the elongated members cannot be properly fixed

Engineering Contradiction:
Improveattaching structure sizeVSAvoidfixing capability
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The attaching structure incorporates a local reinforcement feature where the wall thickness of the cylindrical housing is increased at the tip end where the attaching structure is provided. This localized thickening provides sufficient structural strength for fixing elongated members without requiring larger fixing members, thus achieving both compactness and adequate fixing capability

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3804921B1Robot arm and robot provided with same
Publication Date: 2025.11.05 KAWASAKI JUKOGYO KK
  • EP3804921B1 patent drawingFigure 1
  • EP3804921B1 patent drawingFigure 2
  • EP3804921B1 patent drawingFigure 3(A)~3(B)

AI summary

A robotic arm capable of reducing the size while suppressing damage to a plurality of elongated members inserted therein, is provided. The robotic arm to which an end effector is attached, includes the plurality of elongated members extending to the end effector, a cylindrical housing defining a periphery of an internal space configured to be a passage of the plurality of elongated members, and an attaching structure provided to a tip end of the internal space of the cylindrical housing so as to attach the end effector to a tip-end part of the cylindrical housing. The attaching structure includes insertion holes formed corresponding to the plurality of elongated members so as to insert the plurality of elongated members therein, and fixing members configured to fix the plurality of elongated members to the insertion holes, respectively. The cylindrical housing is formed so that the inner diameter is larger at the tip-end part than at a base-end part.