Spring Assembly with Molded Spring Tongues for Lateral Stiffness

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Solution Overview

Problem

Conventional spring assemblies for vehicle bogie suspension arrangements, such as rubber towers, often fail to provide sufficient stiffness in both lateral and vertical directions, which can lead to inadequate performance in heavy-duty vehicles.

Innovation Solution

A spring assembly comprising washers moulded into an elastomer body with spring tongues, where each spring tongue has a spring base connected to the washer body and a spring tip located at a non-zero distance from the base, providing additional lateral stiffness and adjustable spring force characteristics by varying the distance and thickness ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional rubber tower spring assembly is used, then the structure is simple and easy to manufacture, but the stiffness in lateral and vertical directions is insufficient

Engineering Contradiction:
ImprovestiffnessVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines metal spring tongues with elastomer material to create a composite spring assembly. The spring tongues are made of metal providing high stiffness, while the elastomer body provides flexibility and damping. This composite structure resolves the contradiction by achieving high stiffness through the metal components while maintaining ease of manufacture through the elastomer molding process.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The spring assembly is segmented into distinct functional components: metal spring tongues for lateral stiffness, elastomer body for vertical compliance and damping, and washer layers for structural support. This segmentation allows each component to be optimized for its specific function while maintaining overall manufacturability through modular assembly.

Inventive Principle:
Principle #1Segmentation

2Strength

If spring tongues with non-zero axial distance are used, then lateral stiffness is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvelateral stiffnessVSAvoidmolding precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent merges the spring tongue attachment directly into the elastomer body through co-molding or bonding processes. The spring tongues are integrated with the elastomer rather than being separate assembled parts, which reduces the number of manufacturing steps and maintains precision through a single molding operation. This combining approach resolves the contradiction by achieving complex geometry without proportionally increasing manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple spring tongues are added to provide lateral stiffness, then the suspension performance is improved, but the device complexity increases

Engineering Contradiction:
Improvesuspension performanceVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring assembly with multiple spring tongues serves multiple functions simultaneously: lateral stiffness provision, vertical load bearing through the elastomer, and rotational restraint. The same integrated structure provides all these functions without requiring separate components for each function, resolving the contradiction between performance and complexity.

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

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 spring assembly achieves enhanced stiffness in both lateral and vertical directions, allowing for improved suspension performance and adaptability in heavy-duty vehicles, with the possibility of obtaining requisite stiffness characteristics in multiple horizontal directions.

Implementation Method 1

Each spring tongue has a spring base connected to the spring washer body and a spring tip distal to the spring base. At least a portion of the spring tongue is located at a non-zero distance from the spring base in the axial direction. The spring tongues are moulded into the elastomer body such that when a portion of the elastomer body is subjected to a lateral displacement, such a displacement will be transferred to the at least two spring tongues. Since at least a portion of each spring tongue is located at a non-zero distance from the spring base in the axial direction, such a displacement will result in a lateral spring force from the spring tongues

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3762244B1Spring assembly for a tandem axle vehicle suspension
Publication Date: 2023.06.07 VOLVO TRUCK CORP
  • EP3762244B1 patent drawingFigure 1~2
  • EP3762244B1 patent drawingFigure 3~4
  • EP3762244B1 patent drawingFigure 5a~5b

AI summary

The present invention relates to a spring assembly (14) for a vehicle bogie suspension arrangement (12). The spring assembly (14) comprises a set (16) of washers (20, 22, 24, 26) moulded into an elastomer body (28). The spring assembly (14) has an axial extension in an axial direction (A) and the washers (20, 22, 24, 26) are arranged relative to each other in the axial direction (A). At least one, preferably a plurality, of the washers (20, 22, 24, 26) is a spring washer comprising a spring washer body (30) and at least two spring tongues (32, 34). Each spring tongue (32, 34) has a spring base (36) connected to the spring washer body (30) and a spring tip (38) distal to the spring base (36). At least a portion of the spring tongue (32) is located at a non-zero distance from the spring base (36) in the axial direction (A).