Axially Stabilized Two-Part Piston Ring Design

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Solution Overview

Problem

Existing piston rings lack consistent contact with both piston ring groove flanks, limiting their mobility and adaptability, and existing designs with internal expander springs face challenges in sealing and assembly.

Innovation Solution

A two-piece piston ring with an L-shaped cross-section and an elastic axial stabilization element that presses against one piston ring groove flank while resting on the other, featuring offset wiper webs and a pre-twisted base body to counteract torsion, and a meander or hose spring for improved sealing and mobility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the piston ring is designed to contact both piston ring groove flanks constantly, then sealing performance is improved, but mobility and adaptability are significantly reduced

Engineering Contradiction:
Improvesealing performanceVSAvoidmobility and adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The piston ring is divided into two separate parts: a base body with L-shaped cross-section and an axial stabilization element. This segmentation allows the base body to maintain mobility while the stabilization element provides sealing contact with the groove flanks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The axial stabilization element is designed to be elastic in the axial direction, enabling it to dynamically adapt to groove flank variations while maintaining contact. This dynamic property allows the ring to adjust its position and maintain sealing without compromising mobility.

Inventive Principle:
Principle #15Dynamics

2Reliability

If existing piston rings with internal expander springs are used, then sealing is provided, but assembly challenges and limited adaptability occur

Engineering Contradiction:
ImprovesealingVSAvoidassembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By separating the stabilization function into a distinct axial stabilization element, the assembly process is simplified. The base body can be assembled first, and the stabilization element is then installed to provide sealing, making the assembly process more manageable compared to integrated expander spring designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stabilization and sealing function is extracted from the base body and implemented through a separate axial stabilization element. This extraction allows for independent optimization of each component and simplifies assembly by allowing the stabilization element to be installed after the base body is in place.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the base body is pre-twisted and wiper webs are offset, then torsion is counteracted and wiping performance is improved, but device complexity increases

Engineering Contradiction:
Improvewiping performanceVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The base body is designed with an asymmetric pre-twist and the wiper webs are positioned at offset locations. This asymmetry is intentionally introduced to counteract operational torsion and improve wiping performance by ensuring both wiper webs remain in contact with the cylinder wall during piston movement.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The base body is pre-twisted during manufacturing to anticipate and counteract the torsion that occurs during operation. This preliminary action ensures that when the ring is installed and subjected to operational forces, the pre-twist compensates for the expected deformation, maintaining optimal wiping contact.

Inventive Principle:
Principle #10Preliminary action

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

Enhances sealing and wiping performance by maintaining consistent contact pressure and reducing oil loss, while allowing for better mobility and assembly by compensating for torsion and maintaining effective sealing during power strokes and downward movements.

Implementation Method 1

an axial stabilization element which is elastic at least in the axial direction so that it presses the base body (4) against one piston ring groove flank and is supported on the other piston ring groove flank

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3221620B1Axially stabilized two-part piston ring
Publication Date: 2019.05.01 FEDERAL MOGUL BURSCHEID GMBH
  • EP3221620B1 patent drawingFigure 1~3
  • EP3221620B1 patent drawingFigure 4~6
  • EP3221620B1 patent drawingFigure 7~10

AI summary

The present invention relates to an axially stabilized two-part piston ring (2), comprising a main part (4) with a substantially L-shaped cross-section; which has an outer running surface (12) arranged on a running surface leg (8), and a ring flank piece (10), which together form two legs of the L-shaped cross-section. The piston ring (2) further comprises an axial stabilizing element (6) which is arranged so as to at least partially rest against the ring flank piece (10), said stabilizing element (6) being elastic in the axial direction and said stabilizing element (6) projecting over the running surface leg (12).