Clutch Disc Torsional Damper With Decoupled Centrifugal Pendulum

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Solution Overview

Problem

Existing clutch discs with torsional vibration dampers, particularly those using centrifugal pendulums, suffer from increased mass moment of inertia which worsens clutch engagement acoustics, leading to disturbing metallic noises during rapid engagement situations.

Innovation Solution

A clutch disc design featuring two spring dampers connected in series and a centrifugal pendulum with a flange and centrifugal weights, where the centrifugal pendulum is decoupled from the hub, reducing the total mass moment of inertia by articulating the flange to the clutch disc's side disks or hub, depending on torque direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a centrifugal pendulum is connected to the hub in a rotationally fixed manner, then torsional vibrations are damped effectively, but the mass moment of inertia increases and clutch engagement acoustics deteriorate

Engineering Contradiction:
Improvetorsional vibration dampingVSAvoidclutch engagement noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The centrifugal pendulum is connected to the clutch disc via a dynamic coupling mechanism that allows the connection to engage or disengage based on operating conditions. During normal operation, the pendulum is connected to provide vibration damping. During rapid engagement situations, the coupling allows disconnection to reduce mass moment of inertia and improve acoustic properties.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring damper system is pre-configured with specific stiffness characteristics to anticipate and mitigate the adverse effects of the centrifugal pendulum before they occur. The pre-damper stage is designed to compensate for the increased mass moment of inertia, preparing the system to handle engagement impacts smoothly.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If soft springs are used in the pre-damper to reduce engagement impact, then acoustic properties improve, but the spring damper becomes less effective at blocking high torque

Engineering Contradiction:
Improveengagement impact noiseVSAvoidtorque transmission capability
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The spring damper system is segmented into two distinct stages: a pre-damper stage with soft springs for low-torque engagement situations, and a main damper stage with stiffer springs for high-torque operation. The toothing mechanism provides a third segment for rigid torque transmission when needed, allowing each component to optimize its performance for its specific operating range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the effective spring stiffness parameter dynamically through the two-stage design. At low torques, the soft pre-damper springs are active, providing compliant engagement. At high torques, the system transitions to the main damper stage with higher stiffness, maintaining torque transmission effectiveness while preventing excessive deflection.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the centrifugal pendulum is decoupled from the hub, then the mass moment of inertia is reduced and acoustic properties improve, but the effectiveness of torsional vibration damping decreases

Engineering Contradiction:
Improveclutch engagement noiseVSAvoidtorsional vibration damping
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The coupling between the centrifugal pendulum and the clutch disc is made dynamic rather than fixed. The pendulum can be connected during normal operation to provide vibration damping, and disconnected during rapid engagement to reduce noise, allowing the system to optimize both functions at different times.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

An intermediate coupling mechanism is introduced between the centrifugal pendulum and the clutch disc hub. This intermediary allows the pendulum to be selectively connected or disconnected, mediating between the conflicting requirements of vibration damping and noise reduction, and enabling both functions to coexist.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 improves acoustic properties by reducing the mass moment of inertia to that of a conventional clutch disc without a centrifugal pendulum, minimizing clutch engagement impacts and associated noises.

Implementation Method 1

a spring damper is arranged between the friction linings and the hub, which spring damper transmits torque from the friction linings via two adjacently arranged cover plates to a spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a centrifugal pendulum is used, in which centrifugal weights are displaceably arranged on a flange, which absorb energy during torsional vibrations and release it again with a time delay

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

centrifugal weights are displaceably arranged on a flange, which absorb energy during torsional vibrations

Methodology Applied
Scientific EffectPendulum motion: Pendulum

Implementation Method 4

The centrifugal weights arranged displaceably on the flange are arranged displaceably on the flange by means of roller elements, with both the flange and the respective centrifugal weight having guideways in which the roller elements engage as bearing elements

Methodology Applied
Scientific EffectRolling friction: Roller

Data Source

PatentEP3974676A1Clutch disc with a torsional vibration damper
Publication Date: 2022.03.30 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3974676A1 patent drawingFigure 1~2
  • EP3974676A1 patent drawingFigure 3
  • EP3974676A1 patent drawingFigure 4~5

AI summary

The invention relates to a clutch disc (601) with a torsional vibration damper (105) having two spring dampers (102, 103) connected in series and with a centrifugal pendulum (602), with a hub (112) and a flange (111) arranged thereon, wherein side discs (110) are arranged on both sides of the flange (111), the side discs (110) being radially outward connected to friction linings (108), wherein a first spring damper (102) is arranged as a main damper between the side discs (110) and the flange (111) in a torque-transmitting manner, and a second spring damper (103) is arranged as a pre-damper between the flange (111) and the hub (112) in a torque-transmitting manner, wherein the centrifugal pendulum (602) has at least one flange (114) and centrifugal weights (115) displaceably arranged thereon.wherein at least one flange (114) of the centrifugal pendulum (602) is connected to the flange (111) of the clutch disc (601) in the direction of the moment, in front of the second spring damper (103).