Integrated Leaf Spring Stop for Excessive Deformation Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing suspension systems in motor vehicles with leaf springs require a separate bump stop to prevent wheel impact, complicating design and increasing costs.

Innovation Solution

A limit switch device with a connecting element, typically made of elastomeric material, is integrated into the leaf spring to control the distance between mounting axes, acting as an end-of-stroke stop to prevent excessive deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate bump stop is used to prevent wheel impact, then the leaf spring is protected from excessive deformation, but the suspension design becomes more complex and manufacturing costs increase

Engineering Contradiction:
Improveprotection from excessive deformationVSAvoidsuspension design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the bump stop function with the leaf spring assembly by integrating a stop device that includes a stop element and a connecting element. The stop element is positioned to contact the road surface directly, eliminating the need for a separate bump stop component while maintaining the protective function against excessive deformation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The leaf spring assembly serves its own protective function through the integrated stop device. The connecting element links the stop element to the spring assembly, allowing the system to self-regulate and prevent excessive deformation without requiring external separate components.

Inventive Principle:
Principle #25Self-service

2Reliability

If a separate bump stop is used to prevent wheel impact, then the leaf spring is protected from excessive deformation, but manufacturing costs increase

Engineering Contradiction:
Improveprotection from excessive deformationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the bump stop function with the leaf spring assembly by integrating a stop device that includes a stop element and a connecting element. The stop element is positioned to contact the road surface directly, eliminating the need for a separate bump stop component while maintaining the protective function against excessive deformation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated stop device performs multiple functions: it acts as both a structural component of the leaf spring assembly and a bump stop. The stop element contacts the road surface to prevent excessive deformation, while the connecting element integrates it into the spring assembly, reducing the total component count and manufacturing costs.

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

3Ease of operation

If the connecting element is made of elastomeric material, then the device can deform to allow fixing axes to come closer together, but the maximum separation distance must be precisely controlled

Engineering Contradiction:
Improvedeformation capabilityVSAvoidmaximum separation distance control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent specifies that the connecting element is made of elastomeric material with defined physical and mechanical properties. By controlling the material parameters (elasticity, damping characteristics) and geometric parameters (cross-section, length), the device achieves both deformability during operation and precise control of maximum separation distance between fixing axes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The connecting element uses elastomeric material that combines flexibility for deformation with controlled elastic properties to limit maximum separation. The material selection and dimensional design work together to provide both the ease of operation through deformation and the manufacturing precision for separation distance control.

Inventive Principle:
Principle #40Composite materials

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

Simplifies suspension design and reduces manufacturing complexity and costs by eliminating the need for a separate bump stop while effectively preventing excessive leaf spring deformation.

Implementation Method 1

the connecting element being designed to deform in order, on the one hand, to allow the fixing axes to come closer together and, on the other hand, to limit the separation of the fixing axes to a maximum distance

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4650194A1Leaf spring with integrated leading stop
Publication Date: 2025.11.19 STELLANTIS AUTO SAS
  • EP4650194A1 patent drawingFigure 1
  • EP4650194A1 patent drawingFigure 2
  • EP4650194A1 patent drawing

AI summary

The invention relates to a limit stop device (1) designed to equip a leaf spring (2) of suspension of a motor vehicle, the spring (2) being of the type comprising two fixing axes (4) and several damping leaves (5) extending between the fixing axes (4) of the spring (2), the device (1) comprising two attachment heads (6), each designed to be fixed to a fixing axis (4), the device (1) comprising a linking element (7) connecting the attachment heads (6) and designed to deform in order, on the one hand, to allow the fixing axes (4) to come closer together and, on the other hand, to limit the separation of the fixing axes (4) to a maximum distance, when the heads (6) of the device (1) are fixed on the axes (4) of the spring (2) and the latter deforms to dampen a movement of the vehicle on which it is mounted.