Combustion Engine Axial Thrust Management via Intermediary

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Solution Overview

Problem

Combustion engines with auto-ignition face significant torque variations, leading to micro-blockages and premature wear in the spline connection between the crankshaft and transmission assembly, causing axial forces that damage engine components.

Innovation Solution

Incorporating 'limiting means' that restrict axial movement between the transmission assembly and crankshaft, using a thrust piece and clamping mechanism to prevent axial displacement, ensuring minimal play for assembly and thermal expansion, and utilizing complementary splines to secure the transmission assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a transmission assembly with spline connection is used to transmit engine torque from the crankshaft to the output shaft, then the engine torque can be transmitted to the output shaft, but micro-blockages occur between the transmission assembly and the crankshaft at the spline connection due to torque variations and micro-movements

Engineering Contradiction:
Improveengine torque transmissionVSAvoidspline connection reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

A thrust piece is introduced as an intermediary element between the transmission assembly and the crankshaft. This thrust piece absorbs the axial forces generated by torque variations, preventing direct transmission of these forces to the spline connection. The intermediary thrust piece thus protects the spline connection from micro-blockages and premature wear while maintaining effective torque transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If inclined ramps are formed on the splines to exert axial thrust force on the transmission assembly, then the axial force can be generated, but this axial force moves and causes the transmission assembly to rub on other fixed or moving parts of the engine, damaging them irreversibly

Engineering Contradiction:
Improveaxial thrust forceVSAvoiddamage to engine components
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The thrust piece serves as a mediator that intercepts and contains the axial thrust force within its own structure and mounting location. By positioning the thrust piece between the source of axial force and other engine components, it prevents the axial force from reaching and damaging adjacent parts such as the engine casing, guide bearings, or other pinions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The axial thrust force, which would normally be harmful causing damage to engine components, is converted into a beneficial force by directing it onto the thrust piece. The thrust piece is specifically designed to withstand and manage this axial load, transforming a potentially destructive force into a controlled and contained mechanical action that protects the overall engine system.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If the transmission assembly is allowed to move axially to accommodate assembly and thermal expansion, then dimensional variations can be accommodated, but excessive axial movement causes premature wear of the spline connection

Engineering Contradiction:
Improvethermal expansion accommodationVSAvoidspline connection durability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The thrust piece is designed to allow a controlled, limited amount of axial movement rather than completely restricting axial motion. This partial action approach provides just enough axial play to accommodate thermal expansion and assembly tolerances, while preventing excessive movement that would lead to premature wear of the spline connection. The solution finds the optimal balance between adaptability and durability.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3332138B1Combustion engine, aircraft provided with said engine and method for manufacturing such an engine
Publication Date: 2019.06.19 EUROCOPTER FRANCE SA
  • EP3332138B1 patent drawingFigure 1
  • EP3332138B1 patent drawingFigure 2~3
  • EP3332138B1 patent drawingFigure 4~6

AI summary

The present invention relates to a combustion engine (1) which includes: at least one crankshaft (2) rotating about a first rotation shaft (3); at least one output shaft (4) outputting an engine torque, said output shaft (4) rotating about a second rotation shaft (5) separate from said first rotation shaft (3); at least one transmission assembly (6) rotating about said first rotation shaft (3) and being rotated by said crankshaft (2) in order to transmit said engine torque to said output shaft (4).