Friction Part Y-Shaped Grooves for Oil Film Removal

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Solution Overview

Problem

Existing friction parts for frictionally engaged devices, such as clutches and brakes, face challenges in rapid oil film removal, insufficient cooling, high drag torque, and complex assembly due to groove patterns that are not optimally designed for efficient operation across varying oil volumes, pressures, and temperatures.

Innovation Solution

A friction part with an annular friction surface featuring a Y-shaped groove set, where the first groove extends from the inner or outer edge to a branch point, and the second and third grooves extend to the other edge, inclined in opposite directions, facilitating easy assembly, reducing drag torque, and enhancing cooling through diffuser effects and heat absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional groove patterns are used in friction surfaces, then the structure is simple to manufacture, but the oil film removal speed is insufficient and cooling effectiveness is poor

Engineering Contradiction:
Improveoil film removal speedVSAvoidgroove pattern complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The groove pattern is segmented into multiple functional zones: radial grooves for oil supply, circumferential grooves for oil film removal, and diagonal grooves for pressure distribution. This segmentation allows each groove type to perform its specific function optimally, achieving rapid oil film removal while maintaining manufacturability through standardized groove configurations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from simple radial grooves to a three-dimensional groove network incorporating radial, circumferential, and diagonal orientations. This multi-dimensional groove arrangement creates effective oil flow paths in multiple directions simultaneously, dramatically improving oil film removal speed and cooling effectiveness without excessive complexity.

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

2Temperature

If high oil pressure is applied to cool the friction surface, then cooling effectiveness improves, but the friction lining may be damaged

Engineering Contradiction:
Improvefriction surface temperatureVSAvoidfriction lining integrity
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The groove pattern creates localized pressure zones rather than uniform high pressure across the entire friction surface. Radial grooves supply oil at controlled pressures to specific regions, while circumferential and diagonal grooves distribute and dissipate pressure locally. This localized pressure management cools the friction surface effectively without subjecting the friction lining to damaging high forces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The groove pattern acts as an intermediary pressure distribution system between the oil supply and friction lining. Instead of direct high-pressure oil contact with the friction lining, the grooves mediate by distributing oil pressure gradually across multiple paths, achieving cooling while protecting the friction lining from pressure-induced damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If grooves extend directly from inner edge to outer edge, then oil flow path is simple, but drag torque is not sufficiently reduced

Engineering Contradiction:
Improvedrag torqueVSAvoidgroove configuration complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The groove pattern employs asymmetric configurations where circumferential grooves are positioned at specific offsets from radial grooves, and diagonal grooves create non-uniform pressure distribution. This asymmetry prevents symmetric oil film formation that would maintain drag torque, while the structured asymmetry remains manufacturable through standard machining processes.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The groove pattern incorporates curved and angled transitions rather than straight linear paths. Circumferential grooves follow curved paths around the friction surface, and diagonal grooves create angled pressure distribution patterns. These curved configurations more effectively disrupt oil film continuity and reduce drag torque compared to simple straight grooves.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Speed

If the friction part is designed with precise groove alignment for optimal performance, then oil film removal and cooling improve, but assembly becomes difficult

Engineering Contradiction:
Improveoil film removal speedVSAvoidassembly ease
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The groove pattern is designed with universal symmetry where the same groove configuration performs optimally regardless of rotational orientation. The combination of radial, circumferential, and diagonal grooves creates a pattern that maintains its oil film removal and cooling effectiveness at any rotation angle, eliminating the need for precise alignment during assembly while preserving performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables rapid oil film removal, effective cooling, and smooth engagement of the friction part, reducing drag torque and ensuring reliable operation regardless of oil volume, pressure, and temperature, while simplifying assembly and protecting the friction lining from damage.

Implementation Method 1

coolant flowing through, such as oil, at this deflection point

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

enhancing cooling through diffuser effects and heat absorption

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 3

reducing drag torque, and enhancing cooling through diffuser effects

Methodology Applied
Scientific EffectDiffuser effect: Diffusion

Implementation Method 4

lead to a quick removal of the oil film between the friction part and the associated counterpart

Methodology Applied
Scientific EffectFluid flow: Convection

Data Source

PatentEP2066911B1Friction part for a frictionally acting device, and frictionally acting device having a friction part of said type
Publication Date: 2014.04.16 BORGWARNER INC
  • EP2066911B1 patent drawingFigure 1
  • EP2066911B1 patent drawingFigure 2~5
  • EP2066911B1 patent drawingFigure 6

AI summary

The present invention relates to a friction part (2) for a frictionally acting device, having an annular friction face (18) which has an inner edge (20) and an outer edge (22), wherein at least one set of grooves (24) is provided in the friction face (18), which set of grooves (24) has a first groove (32) which extends from the inner edge (20) or the outer edge (22) to a branching point (34) between the inner edge (20) and the outer edge (22), and a second and third groove (40, 42) which extend in each case from the branching point (34) to the other edge (22, 20). According to the invention, the second groove (40) is inclined in the one peripheral direction (28) and the third groove (42) is inclined in the other peripheral direction (30) of the friction face (18) with respect to a radial line (38) through the branching point (34). The present invention also describes a frictionally acting device having a friction part (2) of said type.