Truck Rear Wheel Suspension Layout for Ground-Level Loading

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Solution Overview

Problem

Existing wheel suspension systems for cargo bikes and flatbed trucks face challenges in maintaining stability and efficiency while minimizing width and allowing for easy loading and unloading of heavy payloads without additional aids, due to limited space and legal width restrictions.

Innovation Solution

A wheel suspension system where each rear wheel is mounted on a separate axle projecting outwards, with a combination of shock absorbers and guides attached to the vehicle frame, allowing for independent movement and efficient force distribution, reducing bending moments, and enabling the loading area to be lowered to the ground.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a narrow wheel suspension system is used to meet width restrictions, then the vehicle can operate on cycle paths and maneuver in limited spaces, but the strength and stability of the wheel suspension are insufficient to handle heavy payloads

Engineering Contradiction:
Improvewidth of wheel suspension systemVSAvoidstrength of wheel suspension
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The wheel suspension system is divided into separate functional components: guide rails that constrain movement, shock absorbers that provide damping, and a modular wheel carrier assembly. This segmentation allows each component to be optimized independently, achieving high strength-to-width ratio.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional lateral suspension expansion to a longitudinal arrangement where the suspension travel occurs primarily in the vertical dimension. The guide rails constrain movement to a narrow lateral envelope while allowing full suspension travel vertically, effectively moving the suspension function to another dimension.

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

2Stability of the object's composition

If the loading area is positioned high for structural stability, then the vehicle maintains stability, but additional aids such as ramps or lifting equipment are required for loading and unloading

Engineering Contradiction:
Improvevehicle stabilityVSAvoidease of loading and unloading
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The loading area height is made dynamically adjustable through the suspension system. The wheel carrier can be positioned at different heights by controlling the shock absorbers, allowing the loading area to be lowered for easy access during loading/unloading operations and raised for stable transport.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The suspension system serves multiple functions: it provides structural support for vehicle stability, enables height adjustment for easy loading/unloading, and acts as the primary suspension mechanism. This multi-functionality eliminates the need for separate loading aids while maintaining stability.

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

3Reliability

If traditional suspension systems are used, then the system provides adequate damping and strength, but the width of the vehicle increases beyond legal restrictions

Engineering Contradiction:
Improvedamping performanceVSAvoidwidth of vehicle
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The guide rails and shock absorbers are merged into an integrated assembly where the guide rails serve both as structural support and as constraints for suspension travel. This merging eliminates redundant components and reduces the lateral width while maintaining damping performance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the operational parameters of the suspension system by constraining lateral movement through guide rails while allowing full vertical travel. This parameter change enables the same damping performance to be achieved within a narrower width envelope by redirecting the suspension motion to the vertical dimension.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the wheel suspension system is designed to lower the loading area to the ground, then loading and unloading becomes easier, but the structural stability and strength are compromised

Engineering Contradiction:
Improveease of loading and unloadingVSAvoidstructural strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The shock absorbers act as intermediaries between the wheel carrier and the vehicle frame. They provide the necessary structural strength and control forces while allowing the loading area to be lowered close to the ground. The guide rails simultaneously provide lateral constraint to maintain structural integrity during low-position operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system provides high strength, stability, and damping while minimizing width, allowing for easy loading and unloading without additional aids, and is modular and cost-effective to produce.

Implementation Method 1

supported in front of and behind the rear wheel (4 view direction) by a combination of separate spring-damper systems (10) and separate guides (11)

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP4644140A1Suspension system for trucks
Publication Date: 2025.11.05 MOTIC GMBH
  • EP4644140A1 patent drawingFigure 1
  • EP4644140A1 patent drawingFigure 2
  • EP4644140A1 patent drawingFigure 3

AI summary

Wheel suspension system (19) for a cargo vehicle with a wheel housing (9), a wheel suspension device (8) for receiving a wheel axle (7), comprising at least two connecting sections (16), at least two guides (11) wherein the guides (11) are connected to the wheel housing (9), at least two spring-damper units (10), at least two piston-cylinder units (12) wherein at least one guide (11), one spring-damper unit (10) and one piston-cylinder unit (12) are located at two opposite ends of the wheel suspension device (8) and are connected to it.In order to ensure, on the one hand, a loading area with the greatest possible clear width for a given vehicle width and, on the other hand, the ability to lower the loading area to the ground, each rear wheel (5) is mounted on a separate axle (7) provided in a wheel suspension device (8) extending in the longitudinal direction of the cargo vehicle and projecting outwards from the loading area, wherein the wheel suspension device (8) is housed in a wheel housing (9) attached to the vehicle frame and is height-adjustable by at least one combination of shock absorber (10) and guide (11) provided in front of and behind the rear wheel (5) - viewed in the direction of travel.