Fiber Composite Trough Chassis for Motorhome Weight Reduction

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Solution Overview

Problem

Motorhomes in the weight class up to 3.5 t typically face limitations in providing comfort and payload due to weight restrictions, with conventional chassis designs resulting in reduced internal space and increased weight, making it difficult to accommodate additional features like emergency vehicles.

Innovation Solution

A trough-shaped chassis design with a support tray and circumferential side wall, utilizing fiber composite materials for increased rigidity and strength, which allows for a lower floor profile, increased storage space, and weight reduction by eliminating the need for additional subfloors and cladding, while maintaining stability and load-bearing capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional ladder frame chassis with metal profile beams is used, then the required load capacity and structural strength are achieved, but the vehicle weight increases and internal storage space is reduced

Engineering Contradiction:
Improveload capacityVSAvoidvehicle weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies fiber-reinforced plastic composite materials to replace conventional metal profile beams in the ladder frame chassis. The composite material components maintain the required load capacity and structural strength while significantly reducing the overall vehicle weight, enabling greater payload capacity within the 3.5t weight class limitation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters from metal to fiber-reinforced plastic composites, altering the density and strength-to-weight ratio characteristics. This parameter change allows achieving the same structural strength with reduced weight, directly addressing the contradiction between load capacity and vehicle weight.

Inventive Principle:
Principle #35Parameter changes

2Volume of stationary object

If a first floor is placed on the profile beams to create storage space, then storage and supply space is formed, but the free internal height of the gap is limited to only 10-30 cm

Engineering Contradiction:
Improvestorage spaceVSAvoidinternal height
Core Design Contradiction:
Volume of stationary objectVSShape

Solution Approach 1:

The patent integrates storage spaces directly into the chassis structure by creating hollow cavities within the composite material frame members themselves, rather than adding a separate first floor that reduces vertical clearance. This dimensional reorganization allows storage volume to be created without compromising the internal height of the living space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Quantity of substance

If the chassis is designed to accommodate more supply components and longer structure, then payload capacity and vehicle length are increased, but the vehicle exceeds the 3.5t weight class limitation

Engineering Contradiction:
Improvepayload capacityVSAvoidvehicle weight
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

By using fiber-reinforced plastic composite materials throughout the chassis construction, the patent achieves significant weight reduction that enables accommodating additional supply components and extending vehicle length while maintaining compliance with the 3.5t weight class limitation, thereby increasing effective payload capacity.

Inventive Principle:
Principle #40Composite materials

4Strength

If conventional metal profile beams are used for the chassis, then structural strength is sufficient, but the construction becomes heavier and requires additional subfloors and cladding

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

Solution Approach 1:

The patent merges multiple functional elements into the chassis structure itself - the composite material frame members simultaneously provide structural strength, incorporate storage cavities, and eliminate the need for separate subfloor and cladding components. This integration reduces construction complexity while maintaining structural integrity.

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 design enhances comfort and payload capacity by increasing storage space without height or length increases, achieving significant weight savings of around 200 kg, allowing for longer vehicle lengths within the 3.5 t weight class, and ensuring stability for vehicles like ambulances and fire brigade vehicles.

Implementation Method 1

utilizing fiber composite materials for increased rigidity and strength

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Data Source

PatentEP2722225B2Frame of a motor home or similar vehicles and chassis for such a frame
Publication Date: 2022.11.02 FAHRZEUGBAU MEIER
  • EP2722225B2 patent drawingFigure 1~3
  • EP2722225B2 patent drawingFigure 4~6
  • EP2722225B2 patent drawingFigure 7~8

AI summary

To enable a lower vehicle weight, or at least a longer body (8) at the same weight as conventional vehicles, for a motorhome, particularly in the weight class up to 3.5 t, the invention provides a chassis with a drive unit (4) and a chassis (6) attached thereto, wherein the chassis (6) has a supporting structure comprising a tub (10) with a subfloor (14) and a surrounding side wall (16), and an interior space within the tub (10) serves as storage space for supply components (44). The tub (10) is also spanned by a floor plate to form a floor (40). The chassis (6) is preferably designed as a single monoblock made of a fiber composite material.