Composite Leaf Spring Transverse Stiffening for Vehicle Stability
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Solution Overview
Problem
Existing ground connections for motor vehicles, particularly those using composite leaf springs, face issues of weight, complexity, and instability, especially in side impacts and under the bonnet space constraints, with existing solutions either being heavy or prone to rotation during impacts.
Innovation Solution
A composite leaf spring ground connection with transverse stiffening means, including elastomer layers and rigid supports, to enhance transverse stiffness without affecting longitudinal stiffness, and a method of manufacturing using pre-loaded half-supports and non-glued elastomer interfaces for improved stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite leaf springs are used to integrate MacPherson front axle functions, then weight is reduced by 10-14 kg, but the vertical bulk cannot be reduced due to shock absorber and spring length constraints
Solution Approach 1:
The patent segments the front axle system into functional components integrated within the composite leaf spring structure. By dividing the MacPherson strut functions (spring, anti-roll, mounting points) into separate integration zones within the leaf spring, the design achieves weight reduction while maintaining necessary vertical dimensions for shock absorbers and springs.
2Ease of operation
If elastic joints with vertical axes are positioned in the plane of the neutral fiber of the leaf spring, then kinematic adjustments are facilitated, but the vehicle becomes unstable during single wheel impact causing rotation of the entire vehicle
Solution Approach 1:
The patent addresses the stability issue by adding a transverse dimension to the joint positioning system. The transverse stiffening element creates a three-dimensional load path that prevents the leaf spring from rotating during single wheel impacts, while the elastic joints maintain their vertical axis orientation for kinematic adjustment ease.
3Strength
If supporting structures are provided with elastomeric interfacial layers to distribute forces evenly, then abrasion is avoided and forces are distributed, but vehicle stability is compromised during impact
Solution Approach 1:
The patent applies local quality by differentiating the properties of different regions of the supporting structure. The elastomeric interfacial layers provide flexibility and force distribution at the contact surfaces, while the transverse stiffening element provides rigidity in the transverse direction to prevent vehicle rotation during impact. This localized differentiation of mechanical properties resolves the contradiction between force distribution and stability.
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 solution effectively stabilizes the vehicle during transverse impacts, reduces weight, and maintains safety by preventing wheelset rotation and abrasion, while optimizing manufacturing costs and kinematic adjustments.
Implementation Method 1
at least one elastomer layer not bonded to these faces that this structure comprises
Implementation Method 2
means for transverse stiffening of said at least one layer which are designed to increase its stiffness in the direction transverse to the blade, so as to oppose the rotation of said train of wheels around a vertical axis
Data Source
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AI summary
The invention relates to a ground contact system for the front or rear wheel set of a motor vehicle, of the type including a composite spring leaf, and to a method for producing said ground contact system. The ground contact system comprises: a composite spring leaf (1) which is to be mounted via the ends (6 and 7) thereof to the wheel set and which has two faces, namely an upper face (2) and a lower face (3), defining two longitudinal edges (4 and 5) connected by the aforementioned ends; and two vehicle chassis (10 and 11) supporting structures (8 and 9) which are mounted to the leaf close to the ends thereof and which each comprise two resilient hinges (14 and 15) to be connected to the chassis and positioned close to the longitudinal edges. According to the invention, each supporting structure is pressed against the faces of the leaf by means of at least one non-bonded elastomer layer, thereby clasping the leaf transversely. Moreover, the leaf and/or each structure comprise means (2b, 3b, 12b, 13b) for transversely stiffening the aforementioned layer, which are designed to increase the stiffness thereof in the direction transverse to the leaf, so as to oppose any rotation of the wheel set about a vertical axis.