Cross-Vehicle Suspension Spring With Switchable Ride-Rate Modes

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Solution Overview

Problem

Existing vehicle suspension systems lack the ability to dynamically adjust wheel constraint strategies to accommodate different driving modes, such as comfort and race modes, due to limited displacement ranges and constrained wheel motions.

Innovation Solution

A vehicle suspension system incorporating a cross-vehicle spring and an active link that can switch between two modes, allowing for different spring rates to accommodate varying driving conditions, with a first mode prioritizing passenger comfort and a second mode prioritizing vehicle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the suspension system uses a fixed spring rate to constrain wheel motion, then the packaging and structural simplicity are maintained, but the ability to adapt to different driving modes (comfort vs. race) is lost

Engineering Contradiction:
Improveadaptability to different driving modesVSAvoidsuspension system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the spring rate adjustable rather than fixed. The active link incorporates a variable restriction mechanism that can dynamically change the degree of restriction on fluid flow between chambers, thereby dynamically adjusting the spring rate of the cross-vehicle spring to match different driving mode requirements (comfort vs. race modes).

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the physical parameter of spring rate through the variable restriction mechanism. By changing the restriction parameter on fluid flow, the system alters the effective spring rate of the cross-vehicle spring, enabling adaptation to different driving conditions without changing the fundamental suspension structure.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the active link permits motion of the first suspension linkage relative to the first attachment point, then passenger comfort is improved through lower spring rate, but vehicle performance deteriorates due to increased wheel motion compliance

Engineering Contradiction:
Improvepassenger comfortVSAvoidvehicle performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system dynamically adjusts the spring rate based on operating conditions. In comfort mode, the variable restriction permits greater fluid flow, creating a softer spring rate that absorbs road imperfections and improves passenger comfort. In race mode, the restriction is reduced to create a stiffer spring rate that prioritizes vehicle performance and wheel control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring rate parameter is changed between two distinct states: a lower spring rate for comfort mode that allows more compliant wheel motion, and a higher spring rate for race mode that provides stiffer wheel constraint. This parameter switching enables the system to optimize for either comfort or performance depending on driving requirements.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the active link fixes the motion of the first suspension linkage relative to the first attachment point, then vehicle performance is improved through higher spring rate, but passenger comfort deteriorates due to reduced suspension compliance

Engineering Contradiction:
Improvevehicle performanceVSAvoidpassenger comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system dynamically switches between two operational states: in performance mode, the variable restriction is configured to fix the motion relationship, creating a stiffer spring rate that enhances vehicle performance and wheel control. In comfort mode, the restriction is adjusted to permit motion, creating a softer spring rate that improves passenger comfort.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring rate parameter is switched between a higher value for performance mode (with fixed motion relationship) and a lower value for comfort mode (with permitted motion). This parameter change enables the suspension to prioritize either vehicle performance or passenger comfort based on driving conditions.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If the cross-vehicle spring and active link constrain wheel motion with a single spring rate, then the suspension system structure remains simple, but the ability to provide different constraint strategies for different driving situations is lost

Engineering Contradiction:
Improvedifferent constraint strategiesVSAvoidsuspension linkage complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cross-vehicle spring and active link assembly serves multiple functions: it can operate in comfort mode with a lower spring rate for compliant wheel motion, or in performance mode with a higher spring rate for stiff wheel constraint. The variable restriction mechanism enables this multi-functionality, allowing the same hardware to provide different constraint strategies for different driving situations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The suspension linkage incorporates a dynamic element (variable restriction) that allows the spring rate to be adjusted between two states. This enables the system to adapt its constraint strategy dynamically - providing softer constraints for comfort mode and stiffer constraints for performance mode - without requiring completely separate suspension systems for each driving situation.

Inventive Principle:
Principle #15Dynamics

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 effectively adjusts to different driving scenarios by altering wheel constraint strategies, enhancing both passenger comfort and vehicle performance based on the selected dynamic mode.

Implementation Method 1

a cross-vehicle spring having a first attachment point coupled to the first suspension linkage and a second attachment point coupled to the second suspension linkage

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a fluid pathway connected between the first volume and the second volume, the fluid pathway comprising a variable restriction so that in the first mode the variable restriction permits fluid to pass between the first volume and the second volume

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 3

in the second mode the variable restriction prohibits fluid from passing between the first volume and the second volume

Methodology Applied
Scientific EffectFluid restriction:

Data Source

PatentEP4717475A1Suspension system
Publication Date: 2026.04.01 MCLAREN AUTOMOTIVE LTD
  • EP4717475A1 patent drawingFigure 1
  • EP4717475A1 patent drawingFigure 2
  • EP4717475A1 patent drawingFigure 3

AI summary

A vehicle comprising: a vehicle body; first and second wheel assemblies each having a rotation axis; first and second suspension linkages, each suspension linkage coupling a respective wheel assembly to the vehicle body to permit motion of the rotation axis of that wheel assembly relative to the vehicle body; a cross-vehicle spring having a first attachment point coupled to the first suspension linkage and a second attachment point coupled to the second suspension linkage; an active link coupling the first attachment point to the first suspension linkage, the active link being configured to have: (i) a first mode in which the active link permits motion of the first suspension linkage relative to the first attachment point so that the cross-vehicle spring and the active link together constrain motion of the first and second suspension linkages with a first spring rate during common motion of the first and second suspension linkages; and (ii) a second mode in which the active link fixes the motion of the first suspension linkage relative to the first attachment point so that the cross-vehicle spring and the active link together constrain motion of the first and second suspension linkages with a second spring rate during common motion of the first and second suspension linkages; wherein the first spring rate is different to the second spring rate.