Swinging Arm Suspension for Stable Leaning Three-Wheel Motorcycles

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Solution Overview

Problem

Three-wheeled vehicles face challenges in maintaining a vertical position without additional support systems, which are either complex or increase weight and cost, and struggle to emulate two-wheeled vehicle handling, especially during curves and rough terrain.

Innovation Solution

A swinging arm suspension system using elastic elements and mechanical linkages forms an articulated quadrilateral joint to maintain vertical stability and allow the front portion to rotate around an orthogonal axis, emulating two-wheeled vehicle handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a three-wheeled vehicle uses a rigid structure to maintain vertical position, then stability is improved, but the vehicle cannot properly handle curves due to centrifugal force affecting the center of gravity

Engineering Contradiction:
Improvevertical stabilityVSAvoidcurve handling capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by replacing the rigid structure with a dynamic swinging arm suspension system. The front portion is connected to the rear portion through a swinging joint that allows automatic lateral inclination during curves. The suspension system includes elastic elements and mechanical linkages that enable the front portion to dynamically adjust its position, emulating two-wheeled vehicle handling while maintaining vertical stability when stationary.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the front portion is made free to rotate to improve curve handling, then adaptability is improved, but mechanisms are needed to keep it vertical when stationary, increasing complexity

Engineering Contradiction:
Improvecurve handling capabilityVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the self-service principle by designing a suspension system that automatically maintains the front portion in a vertical position when stationary without requiring auxiliary devices. The elastic elements and mechanical linkages work together to provide automatic stabilization, while the swinging joint allows natural inclination during curves. The system serves itself by using the vehicle's own motion and gravity to achieve the desired positioning.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If auxiliary devices are added to maintain vertical position, then stability is improved, but weight and cost increase

Engineering Contradiction:
Improvevertical stabilityVSAvoidvehicle weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent applies the merging principle by integrating the stabilization function directly into the suspension system itself, rather than adding separate auxiliary devices. The swinging arm suspension combines the curve handling mechanism with the vertical stabilization function in a unified structure. The elastic elements and mechanical linkages serve dual purposes: enabling dynamic inclination during curves and automatically returning the front portion to vertical position when stationary.

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

The suspension system ensures vertical stability and improved handling, allowing the vehicle to navigate curves and rough terrain while reducing complexity and weight.

Implementation Method 1

at least one elastic element (6) acts on said first lateral connecting rods (3)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the force counteracting the lateral inclination tendency of the vehicle due to the force of gravity

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4342777B1Swinging arm suspension
Publication Date: 2025.08.20 ASKOLL EVA SPA
  • EP4342777B1 patent drawingFigure 1A~1B
  • EP4342777B1 patent drawingFigure 2A
  • EP4342777B1 patent drawingFigure 2B

AI summary

A swinging arm suspension (1) is described, which is adapted to mechanically connect a front portion (11) of a three-wheeled motorcycle (10) to its rear portion (12), which comprises an articulated quadrilateral (2), comprising a pair of first lateral connecting rods (3) with the same length, a lower base segment (4) and a major base segment (5), wherein the length of the segment (4) is shorter than the length of the segment (5). At least one elastic element acts on said first lateral connecting rods (3), which first elastic element (6) is adapted to maintain, when at rest, the articulated quadrilateral (2) in a configuration in which said base segments (4, 5) are parallel to each other. The geometric lengths of said first lateral connecting rods (3) and of said segments (5) and (4) are proportionate to each other so as to ensure that the axis of symmetry of the segment (5) always traverses a constant geometric point coinciding with the lateral rotation center of the tire of the front portion (11) of the motorcycle (10) on which said suspension (1) is adapted to be installed and with respect to which said tire is adapted to rotate, thus modifying its inclination due to the effect of the action of the driver in the moment in which he has to steer.