Centrifugal Clutch Torsion Spring Layout for Compact Capacity Control

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Solution Overview

Problem

Existing centrifugal clutches require large elastic forces to regulate clutch capacity, leading to enlarged device configurations.

Innovation Solution

A centrifugal clutch design featuring a drive plate, clutch weights, and a torsion spring disposed adjacent to the clutch weight's distal end, which applies force resisting centrifugal force, allowing for smaller force regulation of clutch weight displacement and reducing device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a connection spring is connected to the center part of the clutch weight, then the clutch weight displacement can be regulated, but a large elastic force is required and the device configuration becomes enlarged

Engineering Contradiction:
Improveelastic forceVSAvoiddevice configuration size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent changes the spatial arrangement by moving the spring connection point from the center of the clutch weight to the outer peripheral part. This dimensional repositioning allows the spring to act at a greater radial distance, creating a larger moment arm that reduces the required elastic force while maintaining the same regulatory effect on clutch weight displacement.

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

Solution Approach 2:

The patent applies the spring force at the outer peripheral part where the centrifugal force is maximum, rather than distributing force through the center. This concentrated application at the point of maximum stress allows for more efficient force regulation with smaller spring dimensions, reducing overall device size.

Inventive Principle:
Principle #16Partial or excessive action

2Force

If a connection spring with large elastic force is used to regulate clutch weight displacement, then the displacement control is effective, but the clutch capacity cannot be secured and device size is enlarged

Engineering Contradiction:
Improvedisplacement regulation forceVSAvoidclutch capacity
Core Design Contradiction:
ForceVSPower

Solution Approach 1:

By repositioning the spring connection to the outer peripheral part of the clutch weight, the patent creates a more efficient force application geometry. This allows the spring to regulate displacement effectively while transmitting less force, preserving clutch capacity for power transmission without requiring oversized springs.

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

Solution Approach 2:

The patent applies the spring force locally at the outer peripheral part where it is most needed for displacement regulation, rather than through the entire clutch weight structure. This localized force application improves efficiency and allows the clutch to maintain its power transmission capacity.

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

The design secures clutch capacity without enlarging the device configuration by using a torsion spring positioned at the clutch weight's distal end, reducing friction and simplifying assembly and maintenance.

Implementation Method 1

a plurality of clutch weights 120 which includes a clutch shoe 123 extending in a circumferential direction of the drive plate 110 and facing the tubular surface 131 of the clutch outer part 130, is rotatably attached on the drive plate 110 via a swing support pin 113, and swings in a direction in which the clutch shoe 123 comes into contact with or becomes separated from the tubular surface 131 of the clutch outer part 130 in accordance with centrifugal force due to rotational drive of the drive plate 110

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a torsion spring 116 that applies force resisting the centrifugal force with respect to the clutch weight 120. In the feature of the present invention, the torsion spring 116 is disposed adjacent to a distal end 121a serving as an end that is far from the swing support pin 113 of two both end parts of the clutch weight 120 in a circumferential direction facing the tubular surface 131 of the clutch outer part 130, and applies the force resisting the centrifugal force by coming into contact with a side of the distal end 121a

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP3524842B1Centrifugal clutch
Publication Date: 2025.10.29 FCC KK
  • EP3524842B1 patent drawingFigure 1
  • EP3524842B1 patent drawingFigure 2~3
  • EP3524842B1 patent drawingFigure 4~5

AI summary

The present invention relates to a centrifugal clutch (100). The centrifugal clutch (100) includes a drive plate (110) that is rotationally driven directly by the driving force of the engine. The drive plate (110) includes a swing support pin (113) that supports a clutch shoe (123) in a swinging state with respect to a clutch outer part (130), and a spring support (115) that supports a torsion spring (116). The spring support (115) is provided in a standing state on a base (111) adjacent to one distal end (121a) of both end parts of a clutch weight (120) in the circumferential direction that faces a tubular surface (131) of the clutch outer part (130). Both end parts (116b) and (116c) of the torsion spring (116) are respectively hooked on the distal end (121a) of one clutch weight (120) and a proximal end (121b) of the other clutch weight (120) of the two clutch weights (120).