Segmented Oil Scraper Ring With Inclined Drain Grooves

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Solution Overview

Problem

Conventional oil scraper rings for piston rods in large 2-cycle diesel engines are inefficient in reducing oil consumption, as they do not effectively manage the discharge of system oil, leading to excessive drain and increased operational costs.

Innovation Solution

The oil scraper ring design features inclined oil drain grooves on both upper and lower surfaces, with the grooves' cross-sectional area increasing from the inner to the outer side, and strategically placed pins and pin-receiving holes to enhance followability and vertical balance, allowing for improved oil scraping performance and reduced drain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If conventional oil scraper rings with horizontal oil drain slots are used, then the structure is simple and easy to manufacture, but the oil discharge efficiency is poor leading to excessive oil consumption

Engineering Contradiction:
Improveoil consumptionVSAvoidring body structure
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The ring body is circumferentially divided into at least two segments with oil drain grooves provided on both upper and lower surfaces. This segmentation allows oil to be discharged from multiple locations and directions, significantly improving oil discharge efficiency while maintaining reasonable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from horizontal oil drain slots (single plane) to inclined oil drain grooves on both upper and lower surfaces (multiple planes/dimensions). The grooves extend from the inner peripheral side toward the outer peripheral side with an inclination, creating a three-dimensional oil discharge path that enhances gravitational drainage effectiveness

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

2Reliability

If the ring body is circumferentially divided to improve followability, then the oil scraping performance improves, but the manufacturing precision requirements increase

Engineering Contradiction:
ImprovefollowabilityVSAvoidring body division
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The ring body is divided circumferentially into multiple segments that can flexibly follow the piston rod surface. The segmentation is designed with reasonable proportions and connection features that balance followability improvement with manufacturing feasibility, avoiding excessive precision requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The segmented ring body structure allows dynamic adaptation to the piston rod surface during operation. The segments can move relative to each other to maintain contact with the rod surface, improving followability without requiring the entire ring to be manufactured with ultra-high precision as a single piece

Inventive Principle:
Principle #15Dynamics

3Loss of substance

If oil drain grooves are provided only on the upper surface, then the structure is simpler, but the vertical balance and oil discharge efficiency are insufficient

Engineering Contradiction:
Improveoil discharge efficiencyVSAvoidgroove configuration
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

Oil drain grooves are provided on both upper and lower surfaces of the ring body, segmenting the oil discharge paths into multiple channels. This multi-surface groove configuration allows oil to drain from different locations simultaneously, significantly improving overall discharge efficiency while the groove patterns on each surface remain manageable in complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds the lower surface dimension to the groove configuration, transitioning from single-surface to multi-surface oil drainage. The inclined grooves on both surfaces create a three-dimensional drainage network that leverages gravity more effectively, improving oil discharge without requiring excessively complex groove patterns

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 design significantly reduces oil consumption by facilitating easier discharge of oil through combined oil drain grooves, maintaining rigidity, and ensuring excellent followability, resulting in a substantial reduction in the amount of drain over time.

Implementation Method 1

an annular coil spring for pressing the rail to an outer peripheral surface of the piston rod

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

inclined oil drain grooves on both upper and lower surfaces, with the grooves' cross-sectional area increasing from the inner to the outer side

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3135963B1Oil scraper ring for piston rod, and stuffing box provided with said oil scraper ring
Publication Date: 2020.01.29 RIKEN CO LTD
  • EP3135963B1 patent drawingFigure 1
  • EP3135963B1 patent drawingFigure 2(a)~2(c)
  • EP3135963B1 patent drawingFigure 3(a)~3(c)

AI summary

To provide an oil scraper ring for a piston rod having excellent oil-scraping performance to reduce the amount of drain, and a stuffing box comprising such oil scraper rings, a ring body of the oil scraper ring is circumferentially divided to at least two, the ring body comprising a rail at an inner-side longitudinal center, a coil spring groove at an outer-side longitudinal center, and pluralities of oil drain grooves at least one of upper and lower surfaces, which are inclined such that their cross section areas increase as going from the inner side to the outer side.