Thrust washer hooking lugs for bearing shell engagement

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Solution Overview

Problem

Existing thrust washers for flange half-bearings in automotive engines and other systems face challenges in secure engagement and oil distribution, with known designs relying on thin hooking lugs that may not effectively prevent separation and wear, and lacking efficient oil distribution mechanisms.

Innovation Solution

A thrust washer design featuring semi-annular panels with inwardly projecting hooking lugs of varying thickness, where the hooking lug inner portions are thinner and deeper, and oil distribution grooves that extend across the inner edge but not the outer portions, enhancing engagement and oil distribution without deformation of the bearing shell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thin hooking lugs of uniform thickness are used to engage within openings in the bearing shell, then the thrust washer can be assembled onto the bearing shell, but the engagement is not secure and separation may occur under wear and load conditions

Engineering Contradiction:
Improveengagement securityVSAvoidhooking lug structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hooking lugs have non-uniform thickness with a first portion (engaging portion) that is thinner than a second portion (support portion). The thinner first portion allows engagement within narrow openings in the bearing shell, while the thicker second portion provides structural strength and resistance to separation forces. This local variation in thickness resolves the contradiction by optimizing each region for its specific function.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the hooking lugs are made thinner to fit narrow openings in the bearing shell, then assembly is enabled, but the strength and wear resistance of the engagement is reduced

Engineering Contradiction:
Improveassembly capabilityVSAvoidengagement strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The hooking lugs feature a thickness gradient where the first portion (thickness t1) is thinner than the second portion (thickness t2). The thinner first portion facilitates assembly by fitting within narrow openings in the bearing shell, while the thicker second portion maintains engagement strength and wear resistance. This local quality variation resolves the contradiction between ease of assembly and engagement strength.

Inventive Principle:
Principle #3Local quality

3Reliability

If oil distribution grooves are extended across the entire thrust washer surface, then oil distribution is improved, but the structural integrity and engagement capability of the hooking lugs is compromised

Engineering Contradiction:
Improveoil distributionVSAvoidhooking lug integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The oil distribution grooves are configured to extend across the bearing surface but terminate before crossing the hooking lugs. Specifically, the grooves extend radially outward from the inner diameter to a position that stops short of the hooking lugs' location. This local differentiation ensures optimal oil distribution across the bearing surface while preserving the structural integrity and engagement capability of the hooking lugs.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3022453B1Thrust washer
Publication Date: 2020.06.17 MAHLE ENGINE SYST UK
  • EP3022453B1 patent drawingFigure 1A~1D
  • EP3022453B1 patent drawingFigure 1E~3C
  • EP3022453B1 patent drawingFigure 2A~2B

AI summary

A thrust washer (100) for a flange half-bearing, the thrust washer comprising: a substantially semi-annular panel (102) having an inner edge (108) and outer edge; and hooking lugs (110) projecting inwardly from the inner edge of the panel, wherein the hooking lugs have latching edges (118) that are configured to engage within corresponding openings in a bearing shell received by the thrust washer and to prevent disconnection of the thrust washer and bearing shell without deformation of the bearing shell, each hooking lug has a hooking lug inner portion (104A) proximate, around the inner edge of the panel, to the central part of the thrust washer for engaging against edges of the openings in the bearing shell and a hooking lug outer portion (104B) remote, around the inner edge of the panel, from the central part of the thrust washer, and the hooking lug inner portion is thinner than the hooking lug outer portion.