Leaf Spring Insert Molding for Reinforced Coupler Holes
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Solution Overview
Problem
Existing fiberglass leaf springs in automotive applications face challenges in maintaining structural integrity at high-stress areas, particularly where holes are drilled, which can weaken the spring and lead to potential failure.
Innovation Solution
An insert made from a material other than fiberglass, with holes and tapered portions, is coupled to a mold during the manufacturing process, allowing resin and fiberglass to cure around it, providing reinforcement at high-stress areas without exposing the holes to resin, and is later integrated into the leaf spring, maintaining fiber integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If holes are drilled in the leaf spring at high-stress areas, then couplers can be installed for suspension attachment, but the structural integrity and strength of the leaf spring are weakened
Solution Approach 1:
The insert is pre-formed with holes during the leaf spring manufacturing process using resin injection molding, rather than drilling holes after the spring is made. This preliminary creation of holes in the insert (which is then embedded in the spring) allows coupler installation while maintaining structural integrity because the holes are part of a reinforced insert rather than voids in the fiberglass composite itself.
Solution Approach 2:
An insert made of different material (thermoplastic or thermoset polymer) serves as an intermediary component between the coupler and the fiberglass leaf spring. This insert provides a suitable material for drilling holes and installing couplers while the surrounding fiberglass spring maintains its structural integrity, effectively mediating between the conflicting requirements of hole installation and strength preservation.
2Adaptability or versatility
If holes are drilled in the leaf spring to install couplers, then suspension attachment is enabled, but the risk of failure at high-stress points increases
Solution Approach 1:
The insert with pre-formed holes is created and embedded in the leaf spring during manufacturing, enabling future coupler installation while maintaining reliability. The holes are formed in the insert material (not the fiberglass spring) and are designed from the beginning to accommodate couplers, thus enabling suspension attachment capability without compromising the spring's reliability under load.
Solution Approach 2:
The leaf spring becomes a composite structure combining fiberglass reinforcement with a polymer insert material. This composite construction allows the fiberglass to provide overall structural strength and the polymer insert to provide localized functionality for coupler attachment, thereby achieving suspension attachment capability while maintaining or even enhancing the reliability of the high-stress areas through material complementarity.
3Ease of manufacture
If the insert is made with holes for couplers, then ease of coupler installation is improved, but resin may enter the holes during manufacturing causing defects
Solution Approach 1:
A thin overlay layer of the same insert material acts as an intermediary barrier during the resin injection molding process. This overlay temporarily seals the holes in the insert, preventing resin from entering and causing defects, while still allowing the insert to be formed with the necessary hole geometry for future coupler installation. The overlay is later removed to reveal the clean, resin-free holes.
Solution Approach 2:
The holes are pre-formed in the insert before the final resin injection and curing process. This preliminary formation of holes (followed by overlay application and subsequent removal) ensures that when the insert is embedded in the leaf spring, the holes are already properly shaped and positioned for coupler installation, while the manufacturing process is designed to prevent resin contamination during this pre-formed state.
4Reliability
If an insert is added to reinforce high-stress areas, then the durability and stress distribution are improved, but the device complexity and manufacturing process are increased
Solution Approach 1:
The insert manufacturing process is merged with the leaf spring manufacturing process by embedding the insert within the fiberglass composite during the resin injection molding operation. This consolidation means the insert and spring are produced as an integrated assembly in one manufacturing cycle, rather than separately and then assembled, thereby reducing overall manufacturing complexity despite the added reinforcement feature.
Solution Approach 2:
The insert serves multiple functions simultaneously: it provides structural reinforcement at high-stress areas, creates the holes for coupler installation, and acts as a bonding interface between the fiberglass spring and the couplers. This multi-functionality means a single component (the insert) accomplishes what would otherwise require multiple separate features or components, thereby managing device complexity efficiently while achieving enhanced durability.
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 insert enhances the durability of the leaf spring by distributing stress more evenly and reducing wear on couplers, thereby minimizing the risk of failure at high-stress points without compromising the spring's structural properties.
Implementation Method 1
The resin is cured, and the insert adheres to the leaf spring.
Data Source
AI summary
An insert to a mold for a leaf spring comprises a substrate and a hole that extends through the substrate, A post protrudes from the substrate such that the insert, may be coupled to the mold. Further, the post covers the hole on a first end, so the hole is not exposed. On the other end of the hole, a thin overlay that covers the hole. Thus, during a process where resin is added to the mold, no resin enters the hole. The insert, when added to a leaf spring, offers reinforcement on areas where there is high stress. Therefore, holes may be added to a leaf spring at areas of high stress without overly weakening the leaf spring.