Viscous Coupling Power Take Off Assembly Torque Transient Mitigation

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Solution Overview

Problem

Existing power take off systems face damage risks due to torque transients generated when the source of rotational energy is abruptly actuated or when the clutch assembly is engaged, particularly when the rotatably driven accessory has high inertial characteristics that resist sudden changes in rotational speed.

Innovation Solution

A viscous coupling and power take off assembly that integrates a power take off and a viscous coupling, where the viscous coupling reduces or eliminates torque transients by using a fluid-filled housing with protrusions and recesses to allow limited relative rotational movement, controlled by the viscosity of the fluid and adjustable orifices, providing a lost motion connection between input and output shafts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a clutch assembly is provided between the input mechanism and output mechanism to control operation, then the rotatably driven accessory can be operated only when needed, but torque transients are generated when the clutch assembly is abruptly engaged causing damage to the drive train system

Engineering Contradiction:

Improvecontrolled operation of rotatably driven accessoryVSAvoiddamage prevention in drive train system

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A viscous coupling device is introduced as an intermediary between the clutch assembly and the rotatably driven accessory. This viscous coupling acts as a mediator that absorbs and dampens torque transients generated during clutch engagement, preventing damage to the drive train system while maintaining the controlled operation capability provided by the clutch assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The viscous coupling device provides beforehand cushioning by being positioned in the torque transmission path before the torque transients reach the rotatably driven accessory. The viscous fluid within the coupling anticipates and absorbs shock loads during clutch engagement, cushioning the system against potential damage before it occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Speed

If the source of rotational energy is abruptly actuated, then rapid启动 of the system is achieved, but large torque transients are generated that can damage the drive train system

Engineering Contradiction:

Improverapid启动 of the systemVSAvoiddamage prevention in drive train system

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The viscous coupling device converts the harmful torque transients into beneficial viscous damping effects. The sudden torque spikes that would normally cause damage are transformed into controlled viscous flow within the coupling device, dissipating the energy harmfully generated during abrupt actuation as heat through the viscous fluid.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If a viscous coupling is used to minimize torque transient transmission, then damage prevention is improved, but the device complexity increases due to additional components

Engineering Contradiction:

Improvedamage prevention in drive train systemVSAvoidstructure complexity of power take off assembly

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The viscous coupling device is merged with the existing power take off assembly, integrating the torque transient mitigation function into the clutch assembly structure. The viscous coupling shares the housing with the clutch assembly, and the input and output shafts are commonly shared between the two devices, thereby reducing overall device complexity while maintaining damage prevention capabilities.

Inventive Principle:

Principle #5Merging (Combining)

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

Effectively minimizes the transmission of torque transients from the source of rotational energy to the rotatably driven accessory, preventing damage to the drive train system by allowing controlled and reduced rotational movement during abrupt changes.

Implementation Method 1

the viscous coupling reduces or eliminates torque transients by using a fluid-filled housing with protrusions and recesses to allow limited relative rotational movement, controlled by the viscosity of the fluid

Methodology Applied

Scientific EffectViscosity: Viscous Damping

Data Source

PatentUS10843558B2Viscous coupling and power take off assembly for a drive train system

Publication Date: 2020.11.24 PARKER INTANGIBLES LLC

AI summary

A drive train system includes a source of rotational energy, a viscous coupling and power take off assembly that is rotatably driven by the source of rotational energy, and a rotatably driven device that is rotatably driven by the viscous coupling and power take off assembly. The viscous coupling and power take off assembly may include a power take off that is rotatably driven by the source of rotational energy and a viscous coupling that is rotatably driven by the power take off. Alternatively, the viscous coupling and power take off assembly may include a viscous coupling that is rotatably driven by the source of rotational energy and a power take off that is rotatably driven by the viscous coupling. Lastly, the viscous coupling and power take off assembly may include a combined viscous coupling and power take off assembly that is integrated into a single housing.