Bicycle Brake Disc Coupling for Axial Misalignment Control

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Solution Overview

Problem

Bicycle brake discs with non-floating coupling designs suffer from elastic deformations during braking, leading to axial misalignment and abnormal sliding of the braking track, which deteriorates performance and causes excessive brake pad consumption.

Innovation Solution

Introducing a degree of translational freedom between coupling seats of the rotor and carrier, allowing for translation along a specific axis to reduce internal tensions and minimize deformations, thereby preventing undesired sliding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If non-floating coupling is used to reduce weight, then weight is reduced, but elastic deformations occur during braking causing axial misalignment and abnormal sliding

Engineering Contradiction:
Improvebrake disc weightVSAvoidbraking performance stability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent changes the constraint parameters at the coupling interfaces by introducing selective degrees of freedom. Specifically, certain coupling seats are designed with translational freedom along the axial direction while maintaining rotational constraint, allowing the rotor to accommodate thermal expansion and elastic deformations without compromising overall structural integrity or braking performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transforms the rigid static coupling into a dynamic semi-rigid coupling system. The coupling seats with translational freedom allow the rotor to dynamically adjust its position during braking operations, absorbing elastic deformations and preventing the axial misalignment that would occur in a fully rigid non-floating coupling system

Inventive Principle:
Principle #15Dynamics

2Strength

If floating coupling is used to avoid thermal expansion tensions, then thermal stress is reduced, but axial movements of the rotor occur reducing braking efficiency

Engineering Contradiction:
Improvethermal stress resistanceVSAvoidaxial alignment precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies different coupling characteristics to different locations on the rotor. Some coupling seats are designed with translational freedom to handle thermal expansion, while other coupling seats maintain rigid constraints to preserve axial alignment precision. This localized differentiation allows the system to simultaneously manage thermal stresses and maintain braking accuracy

Inventive Principle:
Principle #3Local quality

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 solution effectively reduces elastic and plastic deformations, minimizing sliding issues and improving braking performance by allowing the rotor to translate and discharge tensions without deforming the braking track, thus enhancing the stability and longevity of brake pads.

Implementation Method 1

the heat generated between brake pads and braking track (which can reach and exceed heat powers of 600-800 Watt) causes elastic deformations of the braking track outside of its lying plane

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

causes elastic deformations of the braking track outside of its lying plane

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3441295B1Bicycle brake disc
Publication Date: 2021.02.24 CAMPAGNOLO SRL
  • EP3441295B1 patent drawingFigure 1~2
  • EP3441295B1 patent drawingFigure 3
  • EP3441295B1 patent drawingFigure 4

AI summary

The invention relates to a bicycle brake disc (10) comprising a carrier (14) having a connection portion (12) configured for connection to a hub of a wheel of the bicycle rotatable about a rotation axis (X) and a plurality of coupling seats (24), a rotor (13) comprising a radially outer braking track (15) and a plurality of radially inner coupling seats (18) that at least partially axially overlap the coupling seats (24) of the carrier (14) to define connection areas (25), wherein said rotor (13) and said carrier (14) are joined together by mechanical joints (26) active in said connection areas (25). The constraint between at least one coupling seat (18) of the rotor (13) and a coupling seat (24) of the carrier (14) in a respective connection area (25) has a degree of translational freedom.