Construction Machine Joint Mechanism for Lower Coupling Wear

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Solution Overview

Problem

Existing construction machines, such as excavators, face challenges in reducing the burden on joints, particularly at the coupling portions between the boom and arm or the arm and bucket, which can lead to increased wear and maintenance needs.

Innovation Solution

A joint mechanism for construction machines incorporating a drive unit with an electric motor, a first member and a second member aligned along a rotation axis, and a coupling member that allows relative rotation in the circumferential direction, utilizing spline grooves and pins to facilitate smooth movement and reduce stress on the joints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single coupling wall is used to connect members in construction machines, then the structure is simpler, but the burden on the joint increases leading to faster wear

Engineering Contradiction:
Improvecoupling structure complexityVSAvoidjoint durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coupling structure is divided into multiple coupling walls (first coupling wall and second coupling wall) instead of using a single coupling wall. This segmentation distributes the mechanical burden across multiple contact points, reducing wear on individual joints while maintaining structural integrity and enabling smoother relative rotation between members.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple coupling walls are used to reduce joint burden, then joint durability improves, but the device complexity increases

Engineering Contradiction:
Improvejoint durabilityVSAvoidcoupling structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple coupling walls are merged into a unified coupling structure where the first and second coupling walls work together as an integrated system. This merging approach maintains joint durability through distributed loading while avoiding the complexity of completely separate coupling mechanisms, as the walls are coordinated within a single structural framework.

Inventive Principle:
Principle #5Merging (Combining)

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 joint mechanism reduces wear and tear on the coupling portions by allowing for efficient relative rotation, thereby extending the lifespan of the machine components and minimizing maintenance requirements.

Implementation Method 1

The joint mechanism reduces wear and tear on the coupling portions by allowing for efficient relative rotation

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4711527A1Joint mechanism for construction machine
Publication Date: 2026.03.18 NABTESCO CORP
  • EP4711527A1 patent drawingFigure 1
  • EP4711527A1 patent drawingFigure 2
  • EP4711527A1 patent drawingFigure 3

AI summary

A joint mechanism (21, 22, 23) for construction machine (10) includes: a drive unit (101, 102, 103, 104) including an electric motor (110), the drive unit being capable of outputting torque; a first member (30, 50, 60) including a first coupling wall (37, 53, 64, 253, 353) and a second coupling wall (39, 55, 66, 255, 355) that are aligned in an axial direction along a rotation axis (21J, 22J, 23J) of the torque output by the drive unit; a second member (30, 40) at least partially located between the first coupling wall and the second coupling wall in the axial direction; and a coupling member (71, 81, 91) that couples the first coupling wall and the second member so as to allow relative rotation in a circumferential direction around the rotation axis. The drive unit couples the second coupling wall and the second member so as to allow relative rotation in the circumferential direction.