Friction Member Groove Design for Torque Converter Oil Control

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Solution Overview

Problem

The existing torque converters with multi-plate lock-up clutch devices face challenges in minimizing oil leakage, lubrication, and drag torque due to the design of grooves on friction members, which either allow excessive oil leakage or insufficient lubrication depending on the groove size.

Innovation Solution

The friction member design features V-shaped inner peripheral grooves and radially extending outer peripheral grooves, with elongated circumferential lengths, to inhibit oil flow from the outside and ensure adequate lubrication, reducing leak flow and drag torque by controlling the flow path resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a smaller flow-path cross-sectional area is used for the grooves, then oil leakage is reduced, but lubrication and cooling performance deteriorates

Engineering Contradiction:

Improveoil leakageVSAvoidlubrication and cooling performance

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The groove cross-sectional area varies along its length: the inner peripheral groove portion (first groove) has a smaller cross-sectional area to reduce oil leakage, while the outer peripheral groove portion (second groove) has a larger cross-sectional area to ensure adequate lubrication and cooling. This local variation in geometry resolves the contradiction by optimizing different sections for different functions.

Inventive Principle:

Principle #3Local quality

2Reliability

If a larger flow-path cross-sectional area is used for the grooves, then lubrication and cooling performance is improved, but oil leakage increases

Engineering Contradiction:

Improvelubrication and cooling performanceVSAvoidoil leakage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Force

If grooves penetrate through the friction member from inner periphery to outer periphery, then drag torque is reduced, but oil leakage increases

Engineering Contradiction:

Improvedrag torqueVSAvoidoil leakage

Core Design Contradiction:

ForceVSLoss of substance

Solution Approach 1:

The groove cross-sectional area varies along its length with the inner peripheral portion having a smaller area than the outer peripheral portion. This local variation allows the groove to effectively reduce drag torque while minimizing oil leakage through the friction member.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The groove cross-sectional area is changed along the radial dimension (from inner periphery to outer periphery). This dimensional variation allows the groove to perform multiple functions: reducing drag torque through penetration while controlling oil leakage through area modulation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration effectively reduces oil leakage, ensures sufficient lubrication, and minimizes drag torque in both clutch-on and clutch-off states, meeting stringent transmission specifications.

Implementation Method 1

The inner peripheral groove, having a V-shape opened in the circumferential direction, is formed on the inner peripheral side. Therefore, oil is easily taken through the opening of the first groove during rotation.

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The outer peripheral groove continues to an outer peripheral end of the second groove of the inner peripheral groove and is radially extending in an outer peripheral direction. Therefore, operating oil less easily flows inside through the outer peripheral groove during rotation.

Methodology Applied

Scientific EffectFlow path resistance:

Implementation Method 3

for lubrication and cooling and for reducing drag torque

Methodology Applied

Scientific EffectLubrication: Lubrication

Implementation Method 4

for lubrication and cooling and for reducing drag torque

Methodology Applied

Scientific EffectCooling: Cooling

Data Source

PatentUS9151334B2Friction member, clutch plate, clutch device and torque converter

Publication Date: 2015.10.06 EXEDY CORP

AI summary

A friction member to be used for a lock-up clutch device includes a plurality of friction portions and a plurality of grooves. The plural friction portions are disposed in alignment in a circumferential direction. The plural grooves are formed between or among the plural friction portions and penetrate therebetween or thereamong from the inner peripheral side to the outer peripheral side. Further, each of the plural grooves includes an inner peripheral groove and an outer peripheral groove. The inner peripheral groove is formed in a V-shape, and includes a first groove that is disposed on the inner peripheral side and has an opening, and a second groove that is disposed on the outer peripheral side and continues to the first groove. The outer peripheral groove continues to the outer peripheral end of the second groove of the inner peripheral groove, and radially extends in the outer peripheral direction.