Beveled Side Rail Geometry for Correct Oil Ring Assembly

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Solution Overview

Problem

The existing multi-piece oil rings with vertically asymmetrical side rails face challenges in distinguishing top and bottom directions, leading to incorrect assembly during production and mounting, which affects the functionality and efficiency of internal combustion engines.

Innovation Solution

A side rail with a split ring shape and a beveled portion between the outer peripheral surface and the second axial side surface, featuring a tapered surface with a conical shape, where the first tapered surface portion has an angle of 10° or more and the second tapered surface portion has an angle between 2° and 12°, facilitating easy distinction between top and bottom directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the outer peripheral surface is formed in a vertically asymmetrical shape with slight changes, then the friction against the cylinder inner surface is reduced, but the distinction between top and bottom directions becomes difficult

Engineering Contradiction:
Improvefriction lossVSAvoidassembly direction identification
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The side rail employs a vertically asymmetrical outer peripheral surface configuration where the vertex is positioned closer to one axial side surface than the other. This asymmetry creates distinct top and bottom directions for proper assembly while simultaneously reducing the width of the outer peripheral surface that contacts the cylinder inner surface, thereby reducing friction loss and oil consumption.

Inventive Principle:
Principle #4Asymmetry

2Loss of substance

If the outer peripheral surface width is reduced to minimize friction, then oil consumption is reduced, but the side rail may not provide sufficient oil scraping control

Engineering Contradiction:
Improveoil consumptionVSAvoidoil scraping control
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The side rail features localized functional zones: a first region with a specific outer peripheral surface width optimized for reducing friction and oil consumption, and a second region with different geometric characteristics (asymmetrical vertex positioning) that ensures proper orientation and oil scraping control. This local differentiation allows the rail to simultaneously achieve reduced oil consumption and reliable oil control.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3677764B1Side rail
Publication Date: 2022.11.02 RIKEN CO LTD
  • EP3677764B1 patent drawingFigure 1
  • EP3677764B1 patent drawingFigure 2
  • EP3677764B1 patent drawingFigure 3

AI summary

Provided is a side rail 1 having an outer peripheral surface 14 facing radially outward, an inner peripheral surface 13 facing radially inward, a first axial side surface 11 facing one side in an axial direction, and a second axial side surface 12 facing the other side in the axial direction and parallel to the first axial side surface 11, in which, a beveled portion 30 is provided between the outer peripheral surface 14 and the second axial side surface 12, the beveled portion 30 is formed in a tapered surface having a diameter gradually decreasing from a position on the outer peripheral surface 14 at 0.05 mm or more away from the first axial side surface toward the second axial side surface in the axial direction; a tapered surface 30a is provided between a first tapered surface portion 30a1 with an angle of 10° or more to the axial direction and a second tapered surface portion 30a2 provided between the first tapered surface portion 30a1 and the outer peripheral surface 14 and having a smaller angle of inclination to the axial direction than that of the first tapered surface portion.