Fuel Tank Push-Pull Rods for Stress Compensation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Fuel tanks in motor vehicles face stress due to thermal expansion and fuel removal, which can lead to deformation and seam failure, requiring a solution that balances reliability, durability, cost-effectiveness, lightweight design, and compact installation.

Innovation Solution

The implementation of tension-compression rod units with axial, latching, and radial spring elements, along with a sheet metal holder, to connect and stabilize the two container shells, allowing for assembly tolerance compensation and noise damping, and providing a snap connection mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If push-pull rods are provided to counteract thermal expansion and fuel removal stress, then the structural integrity of the tank is improved, but the device complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The push-pull rod is divided into two separate parts, each with a locking claw. These segments are assembled together to form the complete rod, allowing for easier manufacturing and assembly while maintaining the structural reinforcement function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two rod parts with interlocking locking claws are nested together to form the complete push-pull rod assembly. This nested structure allows the rod to be compact when not in use while providing full structural support when activated.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If complex locking mechanisms are used to secure the rod parts, then the reliability of the connection is improved, but the manufacturing cost and device complexity increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking claws are designed to automatically interlock and secure the two rod parts together through their own geometric shape, without requiring additional fasteners, tools, or complex assembly procedures. The parts self-secure through their inherent design.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The complex mechanical locking system is replaced with a simple geometric interlocking mechanism using conical surfaces and circumferential grooves, which provide reliable connection through basic mechanical principles rather than complex multi-component systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Duration of action of stationary object

If multiple spring elements and latching mechanisms are added to compensate for tolerances and dampen noise, then the durability and comfort are improved, but the weight and manufacturing cost increase

Engineering Contradiction:
ImprovedurabilityVSAvoidweight
Core Design Contradiction:
Duration of action of stationary objectVSWeight of moving object

Solution Approach 1:

The spring elements are designed with specific geometric parameters (cone angle, groove depth, ring shape) that allow them to compensate for assembly tolerances and dampen noise through their elastic deformation characteristics, achieving durability without excessive material usage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The radial spring element is designed as a thin ring-shaped component with spring tabs, providing flexibility and tolerance compensation without adding significant weight. The axial spring element uses a conical geometry that achieves damping and tolerance compensation with minimal material.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enhances the structural integrity and reliability of fuel tanks by compensating for assembly tolerances and damping noise, ensuring durability and cost-effectiveness while maintaining a lightweight and compact design.

Implementation Method 1

An axial spring element 4 is disk-shaped. It includes a spring 4.1 - see figure 3. Because of the spring 4.1, it can be slightly compressed when a pressure is exerted in the axial direction.

Methodology Applied
Scientific EffectSpring compression: Spring

Implementation Method 2

A radial spring element 6 follows. This is ring-shaped. It has spring tabs 6.1 on its circumference. It in turn serves to compensate for tolerances and to dampen noise.

Methodology Applied
Scientific EffectSpring elasticity: Spring

Data Source

PatentEP3121049B1Fuel storage device
Publication Date: 2018.05.09 ALLGAIER WERKE GMBH
  • EP3121049B1 patent drawingFigure 1
  • EP3121049B1 patent drawingFigure 2
  • EP3121049B1 patent drawingFigure 3

AI summary

The invention relates to a fuel storage device comprising the following features: - a fuel container for receiving fuel; - at least one push-pull rod unit fixed to two opposing container areas; - a snap-fit ​​element arranged on the respective container area; - the push-pull rod unit comprises a sleeve; - in the assembled state, the respective end of the sleeve is slipped over the free end of the snap-fit ​​element, whereby a snap connection is formed by an annular bead of one of the two elements and a circumferential groove of the other of the two elements.