Mechanical Clutch Layout to Eliminate Drag Torque in Transmissions

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Solution Overview

Problem

The increasing torque capacity of automatic transmission systems leads to a deterioration in the mountability and weight of clutch apparatuses, and the use of wet multi-plate clutches results in drag torque due to lubricant oil resistance, reducing fuel efficiency.

Innovation Solution

A compact and lightweight clutch apparatus is developed using a mechanical clutch with a ratchet one-way clutch and a mechanical engaging mechanism, eliminating the need for wet multi-plate clutches and incorporating a piston-driven engaging mechanism with return springs for efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If wet multi-plate clutch is used to increase torque capacity, then torque transmission capability is improved, but weight of the clutch apparatus increases

Engineering Contradiction:
Improvetorque capacityVSAvoidweight of clutch apparatus
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent replaces the wet multi-plate clutch (which uses friction between multiple plates) with a mechanical clutch system consisting of a one-way clutch and a brake mechanism. This substitution eliminates the need for multiple friction plates, thereby reducing weight while maintaining torque transmission capability through mechanical engagement rather than friction-based engagement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Force

If wet multi-plate clutch is used to increase torque capacity, then torque transmission capability is improved, but mountability of the clutch apparatus deteriorates

Engineering Contradiction:
Improvetorque capacityVSAvoidmountability
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent segments the clutch system into distinct functional components: a one-way clutch for torque transmission and a separate brake mechanism for control. This segmentation allows for a more compact and simplified overall structure compared to the integrated wet multi-plate clutch system, improving mountability while maintaining the required torque capacity through the combined action of the segmented components.

Inventive Principle:
Principle #1Segmentation

3Force

If wet multi-plate clutch is used, then torque transmission is achieved, but drag torque is generated due to stirring resistance of lubricant oil

Engineering Contradiction:
Improvetorque transmissionVSAvoiddrag torque
Core Design Contradiction:
ForceVSLoss of energy

Solution Approach 1:

The patent replaces the wet multi-plate clutch system that operates with lubricant oil with a mechanical clutch system that does not require continuous lubricant circulation between moving plates. The one-way clutch and brake mechanism engage through direct mechanical contact rather than friction between lubricated surfaces, thereby eliminating the stirring resistance of lubricant oil and the associated drag torque while maintaining torque transmission capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 provides a compact, lightweight clutch apparatus that avoids drag torque generation, improves fuel efficiency, and ensures reliable torque capacity through a mechanical engaging mechanism, enhancing the operational performance of automatic transmission systems.

Implementation Method 1

incorporating a piston-driven engaging mechanism with return springs for efficient operation

Methodology Applied
Scientific EffectElastic potential energy: Spring

Data Source

PatentEP3361112B1Clutch apparatus
Publication Date: 2021.04.14 NSK WARNER
  • EP3361112B1 patent drawingFigure 1A
  • EP3361112B1 patent drawingFigure 1B~2
  • EP3361112B1 patent drawingFigure 3

AI summary

An object is to provide a compact and lightweight clutch apparatus by using a mechanical clutch. A clutch apparatus 1 includes a one-way clutch 10 and a mechanical clutch 20 arranged in parallel in an axial direction, in which the mechanical clutch 20 is movably retained in the axial direction, and when the mechanical clutch 20 moves in the axial direction due to pushing means, the mechanical clutch 20 engages with an end surface of an inner wheel 11 of the one-way clutch 10.