Clutch Spring Preload for Crown Slot Noise Reduction

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Solution Overview

Problem

Torque fluctuations in the drive chain of a motor transmission clutch lead to rattling noises and reduced durability due to relative movement of connecting crowns within slots, which existing solutions fail to adequately address.

Innovation Solution

A spring is connected to the drive plate and abuts against the non-driven side of the drive drum crowns, providing a preload force that maintains contact between the slot and crown connection, preventing noise and ensuring durability by restricting tangential movement and mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the slot width is greater than the crown width to accommodate torque transmission, then the drive connection can handle torque loads, but relative movement occurs between crowns and slots causing rattling noise and reduced durability

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidconnection durability and noise level
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

A spring element is introduced that applies a preliminary counteracting force (preload) to the crown-slot connection. This preload force acts in opposition to the separating forces generated during torque transmission, ensuring that the driving flanks remain in continuous contact. The spring preloads the connection before torque fluctuations occur, preventing the relative movement that causes noise and durability issues.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The solution changes the force parameter by introducing a spring element that applies a constant preload force to the crown-slot interface. This parameter change ensures that the normal force between the driving flanks remains sufficient to prevent relative movement, even when torque fluctuations occur. The spring continuously adjusts the preload to maintain optimal contact conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If a spring is added to prevent rattling noises by preloading the drive plate, then noise is reduced, but the device complexity increases

Engineering Contradiction:
Improverattling noiseVSAvoidclutch structure complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The spring element is integrated directly into the drive plate structure, merging the noise prevention function with the existing drive plate component. This integration eliminates the need for separate spring housings or mounting mechanisms, thereby reducing overall device complexity while still achieving the noise reduction goal through the spring's preload action.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring element is designed to automatically adjust and maintain the preload force on the crown-slot connection without requiring external control systems. The spring self-regulates the force application based on the relative positions of the drive plate and drive drum, providing noise prevention through autonomous mechanical action rather than complex controlled systems.

Inventive Principle:
Principle #25Self-service

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 solution effectively reduces noise generation and enhances durability by maintaining continuous contact between the drive plate and drive drum, while minimizing mechanical stress on the spring material.

Implementation Method 1

a spring (7) connected to the drive plate (4) and abutting against the non-driven side of the crowns (3) in the drive drum (2)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

These both factors, namely the long springs and the small tangential movement, keep the mechanical stress in the finger material below critical values

Methodology Applied
Scientific EffectMechanical stress:

Data Source

PatentEP2246584B1Clutch
Publication Date: 2014.01.01 TRANSMISIONES Y EQUIPOS MECANICOS S A DE
  • EP2246584B1 patent drawingFigure 1
  • EP2246584B1 patent drawingFigure 2
  • EP2246584B1 patent drawingFigure 3

AI summary

Clutch (1), comprising a drive drum (2) having a plurality of circumferentially disposed connecting crowns (3) having a predetermined first width (W1), a drive plate (4) having a plurality of circumferentially disposed slots (6) having a predetermined second width (W3) being greater than the first width (W1) and into which the connecting crowns (3) extend to provide a drive connection between the clutch drum (2) and the clutch plate (4), characterized in a spring (7) connected with the drive plate (4) and firmiy abutting against the non-driven side wall of an associated connecting crown (3) of the clutch drum (2).