Axel Mount Mechanical Stop Leaf Spring Deflection

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Solution Overview

Problem

Leaf springs in heavy commercial vehicles are prone to failure due to excessive vertical deflection and buckling, which can lead to a rough ride and increased maintenance costs.

Innovation Solution

An axel mount with a mechanical stop and/or windup preventer is designed to reduce vertical deflection and prevent buckling by incorporating a housing, support, and mechanical stop, or a windup preventer that limits the flexibility of the leaf spring, thereby enhancing its durability and load-carrying capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the leaf spring is allowed to flex freely to provide suspension, then the cushioning effect is improved, but the vertical deflection becomes excessive causing failure

Engineering Contradiction:
Improveleaf spring durabilityVSAvoidvertical deflection control
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces a mechanical stop that changes the deflection parameter of the leaf spring by limiting its vertical movement. The stop creates a physical barrier that prevents the spring from exceeding a predetermined deflection threshold, thereby controlling the parameter of vertical displacement while maintaining the spring's cushioning function within safe limits.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the leaf spring is made more flexible to improve ride comfort, then the suspension performance is enhanced, but buckling occurs under load

Engineering Contradiction:
Improveride smoothnessVSAvoidresistance to buckling
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The mechanical stop acts as an intermediary element between the leaf spring and the frame. It mediates the interaction by providing a controlled contact point that prevents excessive flexing and buckling while allowing the spring to maintain its flexibility for ride comfort. The stop serves as a middleman that limits the spring's movement without eliminating its suspension function.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Weight of moving object

If the leaf spring thickness is reduced to lower vehicle weight, then fuel efficiency is improved, but the load-carrying capacity decreases

Engineering Contradiction:
Improvevehicle weightVSAvoidload-carrying capacity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The mechanical stop performs a preliminary action by preventing the leaf spring from entering the buckling regime before it occurs. By establishing a physical limit on deflection in advance, the stop protects the reduced-thickness spring from experiencing the high stresses that would cause failure, thereby enabling the use of lighter springs without sacrificing load-carrying capacity.

Inventive Principle:
Principle #10Preliminary action

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 suppresses shock and maintains a smoother ride while allowing vehicles to carry more weight without compromising steering or handling, reducing the likelihood of leaf spring failure and the need for maintenance associated with air suspension systems.

Implementation Method 1

The mechanical stop is coupled to the support and reduces an amount of vertical deflection allowed in an associated leaf spring

Methodology Applied
Scientific EffectMechanical constraint:

Implementation Method 2

The windup preventer coupled to the support and prevents a portion of the leaf spring from buckling

Methodology Applied
Scientific EffectBuckling prevention:

Implementation Method 3

The leaf spring is basically a slightly arced band that bends (e.g., straightens out) to provide a cushioning effect

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3117119B1Leaf spring and mount
Publication Date: 2019.02.20 PRIKKEL III JOHN
  • EP3117119B1 patent drawingFigure 1
  • EP3117119B1 patent drawingFigure 2
  • EP3117119B1 patent drawingFigure 3

AI summary

An axel mount (100) for a leaf spring comprises a housing (102), an aperture (104), a support (106), and a mechanical stop (108). The support (106) runs lengthwise on a shelf (112) of the housing (102) and has a length generally equal to a length of the housing (102). The mechanical stop (108) is coupled to the support (106) and reduces an amount of vertical deflection allowed to an associated leaf spring. Further, a windup preventer (530) may be coupled to the support (108) that prevents the leaf spring from entering a windup mode.