Folded Composite Single-Leaf Spring Eyes for Delamination Resistance
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Solution Overview
Problem
Single-leaf springs made from composite materials face issues such as delamination and mechanical weakness around the eyes, leading to failure under stress, and are costly due to the high price of fiber and resin materials, with existing designs failing to adequately address these problems.
Innovation Solution
A single-leaf spring design using a composite material sheet with fiber plies embedded in a polymer matrix, where the eyes are configured at the fold between the sides, and the manufacturing process involves RTM techniques like Low pressure RTM, High pressure RTM, and High pressure Compression, with lamination and stitching to enhance strength and prevent delamination, allowing for a combination of fiber and metal materials to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single-leaf spring is made from composite material to reduce weight, then weight is reduced, but the area around the eyes experiences delamination and failure under stress
Solution Approach 1:
The patent applies composite materials consisting of fiber plies embedded in a polymer matrix to manufacture the single-leaf spring. This composite structure provides both weight reduction and sufficient mechanical strength, resolving the contradiction between lightweight design and stress resistance. The composite material allows the spring to withstand high stresses without the delamination issues that plague traditional metal springs.
Solution Approach 2:
The patent implements local reinforcement in the eye areas of the leaf spring through specific fiber ply configurations and stitching techniques. This local quality enhancement addresses the stress concentration problems in critical areas while maintaining overall weight reduction, preventing delamination at the eye regions where stresses are most intense.
2Strength
If the thickness of the leaf spring is increased to withstand loads, then load-bearing capacity is improved, but assembly becomes difficult due to space constraints
Solution Approach 1:
The use of composite materials enables the leaf spring to achieve high load-bearing capacity with reduced thickness compared to metal springs. The high strength-to-weight ratio of composite materials allows the spring to withstand required loads while maintaining a thinner profile that fits within available assembly spaces.
Solution Approach 2:
The patent optimizes the thickness parameter of the leaf spring by utilizing the superior mechanical properties of composite materials. This parameter change allows the spring to maintain adequate strength while reducing thickness to acceptable levels for assembly, resolving the contradiction between load-bearing capacity and ease of installation.
3Weight of moving object
If a single-leaf spring is made from composite material, then weight is reduced, but the cost increases due to expensive fiber and resin materials
Solution Approach 1:
The patent applies local quality enhancement by concentrating fiber reinforcement in critical stress areas rather than uniformly throughout the entire spring. This selective reinforcement reduces the total amount of expensive fiber material required while maintaining structural integrity, thereby lowering manufacturing costs while preserving weight reduction benefits.
Solution Approach 2:
The leaf spring is divided into different zones with varying fiber ply configurations based on stress requirements. This segmentation allows optimization of material usage, placing expensive composite materials only where structurally necessary and using less material in low-stress areas, thus reducing overall manufacturing cost.
4Weight of moving object
If existing composite leaf spring designs are used, then weight reduction is achieved, but they fail to provide adequate resistance to stresses and lack automated production capability
Solution Approach 1:
The patent employs advanced composite material technology with specifically configured fiber plies embedded in a polymer matrix to achieve both weight reduction and superior stress resistance. This composite construction eliminates the delamination problems of previous designs while maintaining lightweight characteristics.
Solution Approach 2:
The manufacturing process incorporates preliminary reinforcement measures during the molding stage, including pre-placed fiber plies and stitching patterns that prevent delamination before the spring is put into service. This preliminary action ensures stress resistance is built into the structure rather than added later.
Data Source
AI summary
A single-leaf spring comprising a body and two eyes located at the ends of the body, with the body having an upper side and a lower side, that comprises at least one composite material sheet comprising a series of fiber sheets embedded in a polymer matrix to form a single-leaf spring, where the sheet is a single sheet that runs longitudinally along both sides of the body and the eyes of the leaf spring and that by having both sides folded creates the eyes of the leaf spring.