Motorcycle Clutch Cam Assembly to Prevent Surface Contact

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Solution Overview

Problem

Existing clutch devices suffer from inappropriate functioning due to surface contact between the center-side and pressure-side cam portions, which hinders smooth operation.

Innovation Solution

The clutch device incorporates bosses projecting outward from through holes in the clutch center and pressure plate, allowing for relative rotation and easy elimination of contact between the cam portions, facilitated by circumferential movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the pressure plate and clutch center are assembled with cam portions in contact, then the assembly structure is simple, but the clutch device cannot function appropriately due to surface contact between cam portions

Engineering Contradiction:
Improveassembly structureVSAvoidclutch function
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention introduces asymmetric features (protrusions and recesses) on the cam portions of the pressure plate and clutch center. These asymmetric elements prevent symmetric surface contact between cam portions by providing specific mating geometries that guide proper alignment and eliminate harmful contact areas, thereby maintaining clutch functionality while preserving assembly simplicity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The protrusions and recesses act as intermediary elements between the cam portions. Instead of allowing direct surface contact between the cam surfaces, these intermediary features provide controlled point or line contact through their geometric interaction, preventing the harmful surface contact that would compromise clutch operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the pressure plate rides on the clutch center, then the assembly is compact, but contact between cam portion surfaces prevents appropriate clutch function

Engineering Contradiction:
Improveassembly compactnessVSAvoidclutch operation
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

By incorporating asymmetric protrusions and recesses on the cam portions, the invention maintains the compact assembly configuration while preventing harmful surface contact. The asymmetric geometry ensures that during operation, the cam portions interact through their protrusion-recess interfaces rather than through surface contact, enabling proper clutch function within a compact volume

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The protrusions and recesses create a dynamic interaction mechanism between the cam portions. As the clutch operates and components move relative to each other, these geometric features dynamically engage and disengage, providing the necessary motion control and preventing sustained surface contact that would impair clutch operation

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4368848B1Clutch device and motorcycle
Publication Date: 2025.08.27 FCC KK
  • EP4368848B1 patent drawingFigure 1
  • EP4368848B1 patent drawingFigure 2
  • EP4368848B1 patent drawingFigure 3

AI summary

A clutch device includes a clutch center (40) and a pressure plate (70) operable to move toward or away from the clutch center and rotatable relative to the clutch center. The pressure plate includes a pressure-side cam portion (90). The clutch center includes a center-side cam portion (60). The pressure plate includes a boss (84) extending in movement directions. The clutch center includes a through hole (54H) in which a boss (84) is insertable. The through hole extends along circumferential directions and allows movement of the boss along the circumferential directions and the movement directions. While a surface of the pressure-side cam portion and a surface of the center-side cam portion are in contact with each other, a distal end of the boss projects outward from the through hole.