Variable Rate Leaf Spring Suspension with Tension Shackle

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Solution Overview

Problem

Traditional steel leaf spring suspension systems in vehicles suffer from abrupt changes in spring rate during driving maneuvers, leading to undesirable ride quality, and are heavy due to their construction, which is not ideal for heavy commercial vehicles.

Innovation Solution

A variable rate leaf spring suspension system is introduced, featuring a single or multiple leaf springs with tension or compression shackles and strategically positioned bumpers that adjust the effective length and spring rate in response to load conditions, allowing for customizable spring characteristics without altering the spring's curvature or thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional steel leaf spring arrangements are used, then load spreading capability is improved, but vehicle weight increases

Engineering Contradiction:

Improveload spreading capabilityVSAvoidvehicle weight

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The patent changes the physical parameters of the leaf spring by incorporating variable thickness and variable curvature along its length. The thickness varies from the root to the tip, and the curvature is adjusted to create a progressive spring rate. This allows the spring to maintain load spreading capability while reducing overall material usage and weight compared to traditional uniform steel leaf springs.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material construction for the leaf spring, combining different materials or material configurations to achieve both weight reduction and maintained structural performance. The composite approach allows optimization of strength-to-weight ratio while preserving the load distribution function across the spring assembly.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If multi-plate multi-stage spring rate designs are used, then spring rate control is improved, but ride quality deteriorates due to abrupt changes

Engineering Contradiction:

Improvespring rate controlVSAvoidride quality

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements a dynamic spring rate system where the progressive curvature and thickness variation create a continuously changing spring rate rather than discrete stages. This dynamic progression smooths out the transition between different load conditions, eliminating abrupt changes that would be felt by occupants while still providing adaptability across varying spring rates.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies local quality variations along the length of the leaf spring, with different sections having optimized thickness and curvature characteristics. This localized optimization creates a progressive spring rate that transitions smoothly through different operational phases, improving ride quality while maintaining the ability to control spring rate characteristics in different regions of the spring's deflection range.

Inventive Principle:

Principle #3Local quality

3Force

If heavy commercial vehicles use traditional leaf springs, then load capacity is improved, but fuel efficiency worsens

Engineering Contradiction:

Improveload capacityVSAvoidfuel efficiency

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the geometric parameters of the leaf spring including variable thickness distribution and curvature profiles to achieve maximum load capacity with minimum material. This parameter optimization reduces the overall weight of the suspension system, directly improving fuel efficiency while maintaining the required load bearing capacity for heavy commercial vehicles.

Inventive Principle:

Principle #35Parameter changes

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 system provides a smoother progression of spring rates, enhancing ride quality and reducing weight by allowing for adjustable spring response characteristics, thereby improving suspension dynamics and reducing the overall weight of the vehicle.

Implementation Method 1

a tension shackle pivotably coupled to the vehicle frame about an axis, wherein pivoting of the tension shackle in response to an increasing, upward load reduces the effective length of the leaf spring

Methodology Applied

Scientific EffectPivoting motion: Hinge

Implementation Method 2

a single leaf spring extending from a first end to a second end

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS11660926B2Progressive rate leaf spring for vehicle suspension system

Publication Date: 2023.05.30 RASSINI SUSPENSIONES S A DE CV

AI summary

A variable rate leaf spring vehicle suspension system includes a vehicle frame. The suspension system also includes a single leaf spring extending from a first end to a second end. The suspension system further includes a tension shackle pivotably coupled to the vehicle frame about an axis, the tension shackle defining a channel, the second end of the leaf spring disposed within the channel of the tension shackle, wherein the axis about which the tension shackle is pivotable is below the second end of the leaf spring.