Vehicle Suspension Group With Supplementary Stroke Mechanism

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Solution Overview

Problem

Existing suspension systems in motorized vehicles often lead to wheel detachment from the ground due to maximum extension, particularly under high-speed maneuvers or uneven terrain, as the weight of the non-suspended mass is insufficient to completely extend the elastic subsystem, resulting in loss of traction and directional control.

Innovation Solution

A suspension group incorporating a main spring pre-loaded by pre-loading means and a kinematic connection that provides a supplementary stroke when the main spring reaches its rest length, allowing the non-suspended mass to extend and maintain wheel contact with the ground, utilizing a secondary spring and damper to facilitate this extension and maintain stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the main spring is pre-loaded to provide sufficient elastic force, then the suspension can support the vehicle weight, but the spring reaches maximum extension too easily causing wheel detachment

Engineering Contradiction:
Improveelastic forceVSAvoidwheel contact
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The suspension system is divided into two independent elastic subsystems: a main spring for supporting vehicle weight and a secondary spring for preventing wheel detachment. This segmentation allows each spring to be optimized for its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The secondary spring acts as an intermediary element between the main spring and the wheel assembly. It provides an additional elastic force that activates only when the main spring reaches maximum extension, thereby preventing wheel detachment while not interfering with the main spring's primary function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the suspension extension is increased to prevent wheel detachment, then wheel contact is maintained, but the device complexity and weight increase

Engineering Contradiction:
Improvewheel contactVSAvoidsuspension structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The secondary spring is integrated into the existing suspension structure, merging its function with the main spring system. The secondary spring is positioned to engage only when needed, combining the benefits of extended stroke with the simplicity of a compact design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The secondary spring provides partial action by engaging only when the main spring reaches maximum extension. It does not continuously oppose the main spring's force, but activates selectively to prevent wheel detachment, thereby minimizing complexity while maintaining reliability.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If a counter-spring is used to reduce elastic force near maximum extension, then wheel detachment is prevented, but the rigidity of the elastic subsystem increases significantly

Engineering Contradiction:
Improvewheel contactVSAvoidrigidity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The secondary spring provides a dynamic solution where its rigidity contribution is variable. It remains inactive during normal suspension operation, allowing the main spring to provide smooth elastic support. Only when the main spring reaches maximum extension does the secondary spring engage, dynamically adjusting the system rigidity to prevent detachment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The secondary spring provides localized rigidity enhancement only at the critical point of maximum extension. It does not uniformly increase the rigidity of the entire suspension system, but rather provides targeted support precisely where needed to prevent wheel detachment.

Inventive Principle:
Principle #3Local quality

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 ensures wheel contact with the ground even during elevated load transfers or uneven road surfaces, enhancing stability and traction by automatically providing a supplementary stroke when needed, without significantly altering the main spring's rigidity or adding substantial weight or complexity.

Implementation Method 1

a main spring (16) which extends between a first and a second end (20, 24) of the group, influencing them elastically along a working axis X-X

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

said main spring (16) being pre-loaded by pre-loading means (46) which together influence the spring (16) in compression and impose a rest length thereon L 0

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

said kinematic connection (44) comprising at least one secondary spring (48) which generates an elastic force so as to extend said kinematic connection (44)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

said kinematic connection (44) comprising at least one secondary damper (52) suitable for damping the compression and extension movement of the kinematic connection

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2956317B1Suspension group in particular for motorised vehicles
Publication Date: 2018.06.27 PIAGGIO & C SPA
  • EP2956317B1 patent drawingFigure 1a~1b
  • EP2956317B1 patent drawingFigure 2a~2b
  • EP2956317B1 patent drawingFigure 3a~3b

AI summary

Suspension group for motorized vehicles comprising a main spring which extends between a first and a second end of the group, a main damper connected in parallel to said main spring said main spring being pre-loaded by pre-loading means which together press the spring in compression and impose a rest length thereon, namely the length assumed by the spring when there are no further external loads on the first and/or on the second end of the group except for the pre-load caused by the pre-loading means, wherein the first and second end are connected kinematically to a first and a second mass of the motor vehicle respectively, the first mass being a mass suspended by the suspension group and the second mass being a non-suspended mass.