Self-Supporting Rear Axle Frame for Caravans

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Solution Overview

Problem

Existing rear axle units for leisure vehicles, such as mobile homes or caravans, lack improved design and functionality, particularly in terms of load capacity, weight optimization, and driving comfort, which are essential for enhanced safety and performance.

Innovation Solution

A self-supporting rear axle unit with tubular stiffening elements and independent wheel suspensions, connected to a chassis with profiled side plates and integrated spring/shock absorber elements, allowing for transverse stiffening and flexible axle track configurations, while reducing weight and cost through modular design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a self-supporting axle frame is used, then structural independence and load capacity are improved, but weight increases

Engineering Contradiction:

Improveload capacityVSAvoidaxle frame weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent employs composite construction by combining tubular stiffening elements (axle tubes) with profiled side plates to create a self-supporting axle frame. This composite structure achieves high load capacity while optimizing weight through the synergistic combination of different structural components with complementary mechanical properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The axle frame is segmented into distinct functional components: tubular stiffening elements for primary structural support and profiled side plates for mounting and reinforcement. This segmentation allows each component to be optimized for its specific function, achieving overall structural efficiency with reduced weight compared to a monolithic design.

Inventive Principle:

Principle #1Segmentation

2Strength

If tubular stiffening elements are used, then transverse stiffening and load capacity are improved, but manufacturing complexity increases

Engineering Contradiction:

Improvetransverse stiffeningVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent utilizes tubular stiffening elements with optimized geometric parameters (circular cross-section, standardized wall thicknesses) that provide maximum transverse stiffening efficiency. These parameter optimizations enable the achievement of high structural performance while maintaining compatibility with standard manufacturing processes, thereby reducing overall manufacturing complexity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If independent wheel suspensions are used, then driving comfort and safety are improved, but device complexity increases

Engineering Contradiction:

Improvedriving safetyVSAvoidsuspension system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines spring elements and shock absorber elements into integrated suspension assemblies for each wheel. This merging of functions allows independent wheel suspensions to achieve improved driving comfort and safety while reducing the number of separate components and simplifying the overall suspension system architecture.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The suspension system is designed with universal mounting arrangements on the profiled side plates, allowing the same basic suspension components to serve multiple functions: wheel support, shock absorption, and adjustable axle track positioning. This multi-functionality reduces device complexity by eliminating the need for separate adjustment mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If profiled side plates are used, then functionality and mounting options are improved, but weight increases

Engineering Contradiction:

Improvemounting functionalityVSAvoidside element weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The profiled side plates feature localized reinforcement only in the specific areas where mounting functionality is required, rather than uniformly thick construction throughout. This local quality approach provides the necessary adaptability and mounting options while minimizing weight by using thinner material in non-critical areas.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP4151504A1Rear axle assembly for a recreational vehicle, chassis and recreational vehicle

Publication Date: 2023.03.22 ERWIN HYMER GRP SE

Figure 1~3

AI summary

Rear axle assembly (2) for a recreational vehicle, in particular for a motorhome or caravan, with at least one left wheel suspension (10) and at least one right wheel suspension (11). It is proposed that an axle frame (12) be provided, comprising a left side element (13) and a right side element (14), that the left wheel suspension (10) is at least indirectly attached to the left side element (13) of the axle frame (12), that the right wheel suspension (11) is at least indirectly attached to the right side element (14) of the axle frame (12), and that the axle frame (12) is designed as a self-supporting axle frame (12). Furthermore, a chassis (1) with such a rear axle assembly (2) and a recreational vehicle are specified.