Variable Compression-Ratio Device Oil Channel Design

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Solution Overview

Problem

Existing variable compression-ratio devices do not adequately supply lubricating oil to their input gear, which can lead to inadequate lubrication and potential wear or failure.

Innovation Solution

A variable compression-ratio device design that includes a gear shaft, an input gear, an intermediate gear, an eccentric cam, and a first oil channel within the crankshaft to supply lubricating oil directly to the input gear, with the oil channel positioned inside a primary gear collar for efficient lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a variable compression-ratio device is designed with an eccentric cam and gear mechanism, then the compression ratio can be varied, but the input gear lacks adequate lubrication supply

Engineering Contradiction:
Improvecompression ratio variationVSAvoidinput gear lubrication
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The oil supply system is segmented into multiple dedicated channels: a first oil channel supplies oil to the input gear, and a second oil channel supplies oil to the eccentric cam. This segmentation ensures that each component receives adequate lubrication independently, resolving the contradiction between achieving variable compression ratio through the gear mechanism and maintaining reliable lubrication of the input gear.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If lubricating oil is supplied to the input gear through existing channels, then the structure remains simple, but the input gear receives insufficient lubrication

Engineering Contradiction:
Improveoil channel structureVSAvoidinput gear lubrication
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The oil supply system is divided into separate dedicated channels: a first oil channel specifically for the input gear and a second oil channel specifically for the eccentric cam. This segmentation, while increasing structural complexity slightly, ensures adequate lubrication for each component, resolving the contradiction between structural simplicity and reliable lubrication.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first oil channel acts as an intermediary structure that directly connects the oil supply source to the input gear, ensuring adequate lubrication. This intermediary channel is integrated into the crankshaft structure, balancing the need for adequate lubrication with acceptable structural complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the first oil channel is positioned outside the primary gear collar, then manufacturing is easier, but the lubrication efficiency to the input gear is reduced

Engineering Contradiction:
Improveoil channel positioningVSAvoidlubrication efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The first oil channel is positioned inside the primary gear collar, utilizing the radial dimension of the crankshaft structure. This positioning, while slightly complicating manufacturing, significantly improves lubrication efficiency by placing the oil supply directly at the source, resolving the contradiction between ease of manufacture and lubrication efficiency.

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

Ensures reliable lubrication of the input gear and the eccentric cam driving mechanism, reducing wear and improving the operational efficiency and longevity of the device.

Implementation Method 1

a first oil channel configured to supply lubricating oil to the input gear

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4159989B1Variable compression-ratio device
Publication Date: 2024.08.07 HONDA MOTOR CO LTD
  • EP4159989B1 patent drawingFigure 1
  • EP4159989B1 patent drawingFigure 2
  • EP4159989B1 patent drawingFigure 3

AI summary

An object is to provide oil supply to a variable compression-ratio device. A variable compression-ratio device includes: a gear shaft (52) disposed inside a crankshaft (12) of an internal combustion engine (11) coaxially with the crankshaft (12) and configured to be rotationally driven by a power source (32); an input gear (51) connected to the gear shaft (52); an intermediate gear (50) supported by a crank web (16) of the crankshaft (12) and engaged with the input gear (51); an eccentric cam (31) disposed between a crank pin (17) of the crankshaft (12) and a large end (18a) of a connecting rod (18) and engaged with the intermediate gear (50); and a first oil channel (5) configured to supply lubricating oil to the input gear (51).