Motorcycle Clutch Fitting Teeth for Better Oil Flow

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Solution Overview

Problem

Conventional clutch devices face challenges in efficiently supplying clutch oil to the output-side rotating plates, leading to reduced lubrication and increased wear, especially when the pressure plate is separated from the clutch center.

Innovation Solution

The clutch device incorporates a design where the center-side fitting portion and the pressure-side fitting portion have a specific dimensional tolerance, allowing for a larger gap between them, which facilitates the flow and distribution of clutch oil to the output-side rotating plates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pressure plate is separated from the clutch center, then the clutch can interrupt the transfer of rotation driving force, but the gap formed causes clutch oil to flow to the outside instead of reaching the output-side rotating plates

Engineering Contradiction:
Improveclutch oil supply to output-side rotating platesVSAvoidpressure plate separation for clutch interruption
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces an intermediary structure (the fitting teeth configuration) between the pressure plate and clutch center that mediates the conflict between separation capability and oil supply. The fitting teeth are designed to maintain engagement and guide oil flow even when the pressure plate is separated, thus mediating between the need for separation and the need for continuous oil supply.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent addresses the problem by transitioning from a one-dimensional separation problem to a multi-dimensional solution involving radial positioning of fitting teeth, axial separation distance, and angular distribution of oil flow paths. This dimensional approach allows the pressure plate to separate axially while maintaining radial engagement through fitting teeth for oil supply.

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

2Quantity of substance

If the pressure plate is separated from the clutch center, then clutch interruption function is achieved, but the amount of clutch oil reaching output-side rotating plates is reduced

Engineering Contradiction:
Improveamount of clutch oil to output-side rotating platesVSAvoidpressure plate separation state
Core Design Contradiction:
Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The patent applies preliminary action by pre-configuring the fitting teeth and oil flow channels before separation occurs. The fitting teeth are positioned and sized in advance to ensure they maintain engagement and guide oil flow during subsequent separation, preventing the oil supply problem from arising in the first place.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The fitting teeth structure serves itself dual functions: it maintains mechanical engagement for clutch interruption while simultaneously guiding clutch oil flow to the rotating plates. This self-service mechanism eliminates the need for separate systems for each function.

Inventive Principle:
Principle #25Self-service

3Length of moving object

If a gap is formed between pressure-side fitting teeth and center-side fitting teeth, then pressure plate can separate from clutch center, but clutch oil flows to the outside instead of to output-side rotating plates

Engineering Contradiction:
Improvegap distance between fitting teethVSAvoidclutch oil delivery to rotating plates
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating different gap characteristics at different locations. The fitting teeth are designed with specific local geometries that maintain tight engagement at critical oil flow paths while allowing separation at other areas, thus maintaining oil supply reliability despite overall separation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameters of the fitting teeth (dimensions, positioning, engagement depth) to optimize the gap characteristics. By adjusting these parameters, the design allows sufficient separation distance for clutch function while maintaining adequate engagement for oil flow guidance.

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

This design effectively increases the amount of clutch oil supplied to the output-side rotating plates, enhancing lubrication and reducing wear, even when the pressure plate is farthest from the clutch center.

Implementation Method 1

a larger gap between the center-side fitting portion and the pressure-side fitting portion in a state where the pressure plate is separated from the clutch center... facilitates the flow and distribution of clutch oil to the output-side rotating plates

Methodology Applied
Scientific EffectFluid flow through gap:

Data Source

PatentEP4303461B1Clutch device and motorcycle
Publication Date: 2025.06.18 FCC KK
  • EP4303461B1 patent drawingFigure 1
  • EP4303461B1 patent drawingFigure 2
  • EP4303461B1 patent drawingFigure 3

AI summary

A clutch device (10) includes a clutch center (40) holding output-side rotating plates (22) alternately arranged with input-side rotating plates (20), and a pressure plate (70) movable toward or away from the clutch center. The pressure plate includes pressure-side fitting teeth (77) holding the output-side rotating plates. The clutch center includes center-side fitting teeth (47) holding the output-side rotating plates. In a half-clutch state, a portion of one of the center-side fitting teeth (47) overlap with a portion of one of the pressure-side fitting teeth (77) when seen in the radial directions of an output shaft.