Angled Wear Ring for Die-Casting Piston Seal

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Solution Overview

Problem

Conventional wear rings in die-casting pistons provide a poor seal due to partial contact between facing surfaces, leading to inefficiencies in vacuum and liquid metal containment during the die-casting process.

Innovation Solution

A wear ring with a gap configured to have circumferentially offset pairs of facing surfaces angled relative to a radial line, allowing full contact when compressed, enhancing the seal and eliminating the need for retaining pins and notches, which improves structural integrity and ease of installation/removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional straight cutting is used to machine the gap in the wear ring, then the wear ring can be easily manufactured and installed, but the facing surfaces only contact partially along a contact line, providing a poor seal

Engineering Contradiction:
Improvesealing performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The gap in the wear ring is configured with asymmetric angled facing surfaces rather than parallel straight surfaces. The first and second facing surfaces are angled relative to each other, creating a tapered geometry that ensures full circumferential contact when the wear ring is compressed onto the piston tip. This asymmetric design transforms the contact from a line contact to a full surface contact, eliminating leakage paths while maintaining manufacturability through standard angular machining operations.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If the wear ring is made as a single continuous piece, then the structure is stronger, but it cannot be installed or removed from the piston tip

Engineering Contradiction:
Improveinstallation and removalVSAvoidstructural integrity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The wear ring is designed with a circumferential gap that divides the ring into two separable segments. This segmentation allows the wear ring to be expanded during installation and contracted during removal, enabling easy mounting and dismounting from the piston tip. The gap is positioned and angled such that when the wear ring is compressed onto the piston, the facing surfaces make full contact while the gap remains accessible for tool engagement, maintaining both installability and structural integrity.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the wear ring requires retaining pins and notches for installation, then the wear ring can be securely positioned, but the structural integrity is compromised and installation becomes more complex

Engineering Contradiction:
Improvewear ring positioningVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The design eliminates retaining pins, notches, and other fastening components by incorporating the positioning function directly into the geometry of the wear ring gap and facing surfaces. The angled facing surfaces create a self-centering and self-locking effect when compressed onto the piston tip, with the gap configuration providing inherent rotational positioning. This extraction of fastening elements simplifies the overall structure to a single-component solution while maintaining secure positioning and full sealing contact.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3057726B1Wear ring for die-casting piston, die-casting piston incorporating same, and method of forming same
Publication Date: 2020.04.01 EXCO TECHNOLOGIES LTD
  • EP3057726B1 patent drawingFigure 1
  • EP3057726B1 patent drawingFigure 2
  • EP3057726B1 patent drawingFigure 3

AI summary

A wear ring for a piston of a die-casting apparatus comprises an annular body having a gap extending therethrough. The gap is configured to define at least two circumferentially offset pairs of circumferentially spaced apart facing surfaces. The facing surfaces of each pair are angled and configured to contact each other in a flush manner when the wear ring is circumferentially compressed.