Vehicle Frame Tolerance Compensation via Elastic Connecting Wall

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Solution Overview

Problem

One-piece welded vehicle frames for industrial trucks face excessive stress during drive axle assembly due to manufacturing tolerances, leading to reduced service life and increased costs, and existing solutions either require precise production or compromise driving characteristics.

Innovation Solution

Incorporating a widthwise deformable section in the connecting wall of the vehicle frame allows relative movement between flanges during assembly, compensating for tolerances and reducing assembly stress without compromising strength or stability, achieved through elastic or plastic deformability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the frame is designed as a rigid welded assembly, then the frame strength and stability are improved, but assembly stresses increase due to manufacturing tolerances

Engineering Contradiction:
Improveframe strengthVSAvoidassembly stress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The connecting wall is segmented into a rigid section and a deformable section. The rigid section maintains frame strength and stability, while the deformable section accommodates assembly stresses through controlled deformation, thus resolving the contradiction between rigidity and stress reduction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the connecting wall have different mechanical properties: the first section has high rigidity for structural strength, while the second section has reduced rigidity for stress absorption. This local differentiation allows the frame to simultaneously achieve strength and stress reduction.

Inventive Principle:
Principle #3Local quality

2Stress or pressure

If manufacturing tolerances are reduced to minimize assembly gaps, then assembly prestress is reduced, but production costs and workload increase

Engineering Contradiction:
Improveassembly prestressVSAvoidproduction cost
Core Design Contradiction:
Stress or pressureVSEase of manufacture

Solution Approach 1:

The rigidity parameter of the connecting wall is changed locally in the deformable section, allowing the structure to accommodate tolerance variations without requiring tight manufacturing tolerances. This enables standard production processes to be used while still achieving low assembly prestress.

Inventive Principle:
Principle #35Parameter changes

3Stress or pressure

If the frame rigidity is reduced to absorb assembly stresses, then assembly stresses are reduced, but driving characteristics deteriorate due to large forces and shearing forces

Engineering Contradiction:
Improveassembly stressVSAvoiddriving characteristic
Core Design Contradiction:
Stress or pressureVSEase of operation

Solution Approach 1:

The connecting wall is divided into rigid and deformable sections. The rigid section maintains the frame's overall stiffness for good driving characteristics, while the deformable section locally absorbs assembly stresses, thus resolving the contradiction between global rigidity and local stress absorption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting wall has non-uniform rigidity distribution: high rigidity in the first section for structural integrity and driving performance, low rigidity in the second section for stress accommodation. This local quality differentiation resolves the contradiction between frame stiffness and stress absorption.

Inventive Principle:
Principle #3Local quality

4Stress or pressure

If a two-part frame with screw connection is used, then assembly prestress is reduced, but handling effort and assembly work increase

Engineering Contradiction:
Improveassembly prestressVSAvoidframe structure
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The frame is designed as a one-piece welded assembly with an integrated deformable section in the connecting wall. This combines the benefits of stress reduction with the simplicity of a unified structure, avoiding the increased complexity of multi-part constructions with separate fastening elements.

Inventive Principle:
Principle #5Merging (Combining)

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

This solution reduces assembly stress, improves ride quality, extends component life, and lowers production costs by allowing targeted tolerance compensation without affecting the frame's strength or stability.

Implementation Method 1

a) an elastic section (26) having a reduced rigidity with respect to the width direction of the vehicle compared to the adjacent sections of the connecting wall (22)

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3501952B1Tolerance compensation in assembled parts in components by means of elastic elements
Publication Date: 2021.01.06 JUNGHEINRICH AG
  • EP3501952B1 patent drawingFigure 1~2

AI summary

The present invention relates to a vehicle frame, in particular for a forklift truck, comprising a right and a left flange (20a, 20b) extending from a base substantially in the longitudinal direction (L) of the vehicle away from the center of the vehicle, between which a drive axle assembly extending in the lateral direction (B) of the vehicle can be mounted, and a connecting wall (22) extending in the lateral direction (B) of the vehicle and connecting the two flanges (20a, 20b) at their respective bases, wherein the connecting wall (22) has at least one section (26) that is deformable in the lateral direction (B), which, when the drive axle assembly is mounted, allows the two flanges (20a, 20b) to move in the lateral direction (B) of the vehicle relative to each other.