Friction Clutch Leaf Spring Inclination Torque Transmission

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Solution Overview

Problem

Existing drive train systems for motor vehicles with friction clutches struggle to transmit higher torque efficiently due to limitations in the design of the friction clutch components, particularly the leaf springs, which can buckle under torque loads, reducing contact pressure and overall transmission efficiency.

Innovation Solution

The drive train system incorporates a friction clutch design where leaf springs are arranged between the clutch housing and pressure plate, or between the counter-pressure plate and pressure plate, with an inclined configuration that generates an additional engagement force component in the direction of rotation, reducing the release force component on the pressure plate and increasing contact pressure, thereby enhancing torque transmission. This is achieved by adjusting the attachment points of the leaf springs and using different friction linings with varying coefficients of friction to manage buckling and increase torque capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the leaf springs are arranged between the clutch housing and the pressure plate to apply a release force component, then the clutch can be disengaged reliably, but the leaf springs buckle under torque loads, reducing contact pressure and torque transmission capability

Engineering Contradiction:
Improveclutch disengagement reliabilityVSAvoidtorque transmission capability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent repositions the leaf springs from a purely axial arrangement to an inclined arrangement that extends into the radial dimension. By angling the leaf springs relative to the axial direction, they generate both an axial release force component and a radial engagement force component. This dimensional change allows the leaf springs to contribute to torque transmission while maintaining their disengagement function, resolving the contradiction between reliable disengagement and torque transmission capability.

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

2Strength

If the contact pressure of the pressure plate is increased to transmit higher torque, then the torque transmission capability is improved, but the release force component acting on the pressure plate increases, causing the leaf springs to buckle more easily

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidleaf spring stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent employs the inclined leaf spring arrangement to generate a radial engagement force component that acts as a counterbalancing force to the axial release force component. This radial component effectively counteracts the buckling tendency of the leaf springs under high contact pressure conditions. By creating this counterbalancing force through geometric arrangement rather than additional structural reinforcement, the system can maintain high torque transmission capability while preserving leaf spring stability.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Stability of the object's composition

If the thickness of the leaf springs is increased to prevent buckling, then the leaf spring stability is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveleaf spring stabilityVSAvoidleaf spring manufacturing ease
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Instead of changing the dimensional parameters of the leaf springs (such as thickness), the patent changes the geometric parameter of the leaf spring arrangement - specifically the inclination angle. This parameter change in the configuration rather than the physical dimensions allows the system to achieve improved stability without increasing manufacturing complexity. The leaf springs maintain their original thickness and material properties, making them equally easy to manufacture while gaining enhanced stability through their angled arrangement.

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

The enhanced friction clutch design effectively increases torque transmission by compensating for decreasing contact pressure due to wear and preventing leaf spring buckling, resulting in improved efficiency and reliability of the drive train system.

Implementation Method 1

the leaf springs being arranged between the clutch housing and the pressure plate and/or between the counter-pressure plate and the pressure plate in such a way that they are in the engaged state generate another engagement force component in the direction of rotation of the driving motor shaft, which reduces the release force component acting on the pressure plate

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the friction clutch has a clutch disc which, in the engaged state of the friction clutch, is frictionally clamped between the counter-pressure plate and the pressure plate

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3314138B1Powertrain for a motor vehicle comprising a friction clutch and friction clutch for a powertrain of a motor vehicle
Publication Date: 2020.09.02 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3314138B1 patent drawingFigure 1
  • EP3314138B1 patent drawingFigure 2~4

AI summary

Disclosed is a powertrain for a motor vehicle, said powertrain comprising at least an internal combustion engine, which is designed to drive an engine shaft in a single direction of rotation, and a friction clutch, of which the input side is indirectly or directly connected to the engine shaft and the output side is indirectly or directly connected to an input shaft of a transmission, wherein the input side of the friction clutch has at least a clutch housing (13), a counter pressure plate (14) and a pressure plate (15) which can be displaced to a limited degree in the axial direction of the friction clutch relative to at least the counter pressure plate and which is non-rotatably connected to the clutch housing (13) and/or the counter pressure plate (14) by means of leaf springs (19) that are distributed over the circumference of the friction clutch and which exert a release force component, and wherein the output side of the friction clutch has at least a clutch disc (16) which, in the engaged state of the friction clutch, is frictionally clamped between the counter pressure plate and the pressure plate, on which pressure plate additionally an engagement force component exerted by the actuating device acts, and the leaf springs are arranged between the clutch housing and pressure plate and/or between counter pressure plate and the pressure plate such that, in the engaged state, the springs generate an additional engagement force component in the direction of rotation of the driven engine shaft, by means of which additional component the release force component acting on the pressure plate in the axial direction of the friction clutch is reduced.