Construction Machine Joint Coupling for Lower Rotational 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 wear and tear.
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
Engineering Contradiction Analysis
1Device complexity
If a single coupling wall is used to connect members, then the structure is simpler, but the burden on the joint increases leading to wear and tear
Solution Approach 1:
The coupling structure is divided into multiple coupling walls (first coupling wall and second coupling wall) that are aligned in the axial direction. Each coupling wall independently connects to the corresponding member, distributing the mechanical burden and reducing wear on individual joints while maintaining structural simplicity through the modular segmented design.
2Reliability
If multiple coupling walls are used to reduce burden on joints, then the structure becomes more complex
Solution Approach 1:
Multiple coupling walls are merged into a single integrated coupling structure that connects to members through aligned axial positions. This combining approach distributes the joint burden across multiple coupling interfaces while maintaining overall structural simplicity through the unified merged design, avoiding the complexity of completely separate coupling systems.
3Strength
If rigid coupling is used between members, then the structural strength is higher, but the stress on joints during rotation increases
Solution Approach 1:
The coupling structure incorporates rotational movement capability between the drive unit output portion and the member, transitioning from a static rigid connection to a dynamic articulated connection. This allows the joint to accommodate rotational motion while maintaining structural strength through the coupled connection, reducing stress concentrations that would occur in a purely rigid fixed connection during operational movements.
Data Source
AI summary
A joint mechanism for construction machine includes: a drive unit including an electric motor, the drive unit being capable of outputting torque; a first member including a first coupling wall and a second coupling wall that are aligned in an axial direction along a rotation axis of the torque output by the drive unit; a second member at least partially located between the first coupling wall and the second coupling wall in the axial direction; and a coupling member 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.