Hybrid Leaf Spring Suspension Weight Reduction
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Solution Overview
Problem
Existing leaf spring suspension systems for heavy vehicles are weight-intensive due to additional spring stages and multiple plates, which hinder weight reduction efforts aimed at improving fuel efficiency.
Innovation Solution
A hybrid leaf spring suspension system featuring a first stage steel spring plate and a second stage composite material spring plate, both with varying cross-sectional areas, where the second stage is shorter than the first, and includes bumpers for adjustable spring rate characteristics, reducing weight and enhancing lateral stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a parallel leaf spring arrangement with multiple spring plates is used to provide a second stage spring rate, then the suspension system achieves desired spring rate characteristics, but the weight of the assembly increases
Solution Approach 1:
The patent applies composite materials by combining a steel first stage leaf spring with a composite material second stage leaf spring. The composite material spring provides the necessary spring rate characteristics while significantly reducing weight compared to traditional all-steel multi-plate arrangements. This resolves the contradiction by maintaining functional performance (spring rate characteristics) while eliminating the weight penalty through material substitution.
Solution Approach 2:
The patent segments the leaf spring system into two distinct stages with different materials and functions. The first stage uses steel for primary load-bearing, while the second stage uses composite material for weight reduction and supplemental spring rate. This segmentation allows each component to be optimized for its specific function, achieving overall performance without the weight of a complete multi-plate steel assembly.
2Adaptability or versatility
If multiple spring plates are stacked to form leaf spring stages, then the desired spring rate characteristics are achieved, but the device complexity increases
Solution Approach 1:
By using composite materials for the second stage leaf spring, the patent reduces the number of steel plates needed while achieving the same spring rate characteristics. The composite material's inherent properties allow for a simpler, lighter construction that maintains the required mechanical performance without increasing assembly complexity.
Solution Approach 2:
The patent applies different material qualities to different parts of the system: steel for the first stage where high strength and durability are critical, and composite material for the second stage where weight reduction is prioritized. This local differentiation of material properties optimizes each component for its specific operational requirements while simplifying the overall assembly.
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 hybrid system achieves significant weight reduction, improved stiffness, and flexible spring response characteristics, while avoiding packaging issues and maintaining desired spring rate characteristics, thus enhancing fuel efficiency and vehicle performance.
Implementation Method 1
a first stage leaf spring operatively coupled at a first end and a second end to the chassis rail, the first stage leaf spring formed of a single steel spring plate and having a first length. Yet further included is a second stage leaf spring operatively coupled to the first stage leaf spring in a stacked arrangement proximate the axle
Data Source
AI summary
A leaf spring vehicle suspension system includes a chassis rail. Also included is an axle. Further included is a first stage leaf spring operatively coupled at a first end and a second end to the chassis rail, the first stage leaf spring formed of a single steel spring plate and having a first length. Yet further included is a second stage leaf spring operatively coupled to the first stage leaf spring in a stacked arrangement proximate the axle, the second stage leaf spring formed of a composite material and having a second length that is less than the first length of the first stage leaf spring.