Cascaded Linear Motion Mechanism for Rigid Telescopic Arms
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Solution Overview
Problem
The challenge is to enhance the rigidity of a linear motion mechanism for a robot arm without increasing its size or weight, as existing telescopic structures face a trade-off between rigidity and slidability, where increased rigidity often results in larger and heavier mechanisms.
Innovation Solution
The implementation of a cascaded linear motion mechanism with ball spline mechanisms between cylindrical elements, allowing for improved rigidity distribution without enlarging the mechanism's size, by using thicker spline shafts at the base and thinner ones at the end, and strategically arranging ball spline mechanisms to maintain mobility and prevent collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a multi-stage linear motion rail and cover structure is used to increase rigidity, then the rigidity of the telescopic arm is improved, but the outside diameter of the outer-circumferential cover increases, causing the entire arm to increase in size and weight
Solution Approach 1:
The patent applies local quality by varying the thickness of spline shafts at different positions - thicker at the base where rigidity is most needed, and thinner at the end where less rigidity is required. This localized optimization improves overall rigidity without uniformly increasing the size and weight of the entire arm structure.
2Ease of operation
If clearance is provided in sliding portions to maintain low sliding resistance, then the slidability of the telescopic arm is improved, but the rigidity of the entire arm is reduced
Solution Approach 1:
The patent segments the linear motion mechanism into multiple independent linear motion elements that are cascaded together. Each element has its own shaft and slider components with necessary clearances for smooth operation. This segmentation allows each segment to maintain low sliding resistance through appropriate clearance design while the overall structure achieves high rigidity through the cascaded arrangement and strategic thickening of shafts at critical locations.
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
This configuration effectively enhances the rigidity of the linear motion mechanism while maintaining its compact size and weight, enabling it to handle greater extension lengths and heavier loads without obstructing linear motion, thus addressing the need for improved structural integrity.
Implementation Method 1
a plurality of linear motion elements that are cascaded in a mutually movable manner; a shaft fixed to one of adjacent linear motion elements among the plurality of linear motion elements; and a slider movably engaged with the shaft
Data Source
AI summary
A linear motion mechanism includes: a plurality of linear motion elements that are cascaded in a mutually movable manner; a shaft fixed to one of adjacent linear motion elements among the plurality of linear motion elements; and a slider movably engaged with the shaft and fixed to the other of adjacent linear motion elements.