Motorcycle Frame Struts for Braking Stiffness Without Added Weight

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Solution Overview

Problem

Existing motorcycle frames, particularly in racing motorcycles, suffer from the 'frame closure' phenomenon during braking, which is exacerbated by powerful braking forces, leading to excessive engine advancement and reduced stiffness, necessitating over-sized engine support brackets that increase weight and compromise performance.

Innovation Solution

A motorcycle frame design featuring a main body with connected brackets and struts that are rigid in compression and free in traction, allowing the engine mass to discharge on the brackets during braking and elongate during acceleration, while maintaining flexibility during cornering and acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If over-sized engine support brackets are used to prevent frame closure during braking, then longitudinal stiffness is improved, but weight increases and lateral stiffness deteriorates

Engineering Contradiction:
Improvelongitudinal stiffnessVSAvoidweight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent applies a dynamic solution by using struts that are rigid in compression but free in traction, allowing the bracket assembly to adapt its stiffness characteristics based on loading conditions. During braking, the struts engage to provide longitudinal stiffness; during cornering, they remain free to allow lateral flexibility

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements local quality by making different parts of the support structure have different mechanical properties - the struts are designed to be rigid in compression while free in traction, and the brackets have specific geometric features (such as inclined surfaces) that engage only under compressive loads, providing localized stiffness where needed without compromising overall flexibility

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If over-sized engine support brackets are used to prevent frame closure during braking, then longitudinal stiffness is improved, but lateral stiffness deteriorates

Engineering Contradiction:
Improvelongitudinal stiffnessVSAvoidlateral stiffness
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent applies a dynamic solution by using struts that are rigid in compression but free in traction, allowing the bracket assembly to adapt its stiffness characteristics based on loading conditions. During braking, the struts engage to provide longitudinal stiffness; during cornering, they remain free to allow lateral flexibility

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent segments the support function into two independent systems: struts for longitudinal load management and brackets for lateral support. This segmentation allows each component to be optimized for its specific function without compromising the other

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If traditional rigid brackets are used to support the engine, then longitudinal stiffness is improved, but weight increases

Engineering Contradiction:
Improvelongitudinal stiffnessVSAvoidweight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent replaces static rigid brackets with dynamic struts that engage only when needed (during braking). The struts transition from a non-load-bearing state to an engaged state, providing stiffness on-demand rather than maintaining constant rigidity, thereby reducing weight

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the mechanical parameters of the support structure by using struts with different engagement characteristics - rigid in compression, free in traction. This parameter change allows the system to provide high stiffness when needed while maintaining low weight during normal operation

Inventive Principle:
Principle #35Parameter changes

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

Enhances stability during braking by absorbing compressive loads and maintaining flexibility during acceleration and cornering, improving tire grip and overall performance by balancing stiffness and weight.

Implementation Method 1

said frame comprises a pair of struts configured to be rigid in compression and free in traction

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

said frame comprises a pair of struts configured to be rigid in compression and free in traction

Methodology Applied
Scientific EffectTension: Tension

Data Source

PatentEP4565476B1Motorcycle frame with variable stiffness
Publication Date: 2026.04.08 PIAGGIO & C SPA
  • EP4565476B1 patent drawingFigure 1~2
  • EP4565476B1 patent drawingFigure 3~6

AI summary

A motorcycle frame is disclosed, comprising a main body, extending in a longitudinal direction, and a pair of brackets, configured to support an engine, at least partially, the brackets being connected to the main body. The frame comprising a pair of struts configured to be rigid in compression and free in traction, each strut being connected at a front end to the main body and at a rear end to one of said brackets.