Engine Housing Reinforcement for Thermal Gear Alignment

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Solution Overview

Problem

Modern engine housing components made from aluminum experience thermal expansion issues that lead to increased backlash between gears, causing wear and vibrations due to mismatched coefficients of thermal expansion with gear wheels made from materials like steel.

Innovation Solution

Incorporating a reinforcement member with a different coefficient of thermal expansion into the engine housing component, which surrounds the shaft bores and bearing structures, and coupling a bearing cap made from similar material to the reinforcement member, to manage thermal expansion and maintain optimal gear alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the engine housing component is made from aluminum to reduce weight, then the weight of the engine housing is reduced, but the coefficient of thermal expansion increases causing backlash between gears

Engineering Contradiction:
Improveweight of engine housingVSAvoidgear alignment precision
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The engine housing assembly uses a composite structure combining aluminum housing component with a reinforcement member made of material having a lower coefficient of thermal expansion. This composite approach allows the housing to maintain lightweight aluminum construction while the reinforcement member (with material having different thermal expansion properties) compensates for thermal expansion differences, thereby maintaining gear alignment precision despite temperature changes

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The reinforcement member is strategically positioned within the aluminum housing component to specifically address the thermal expansion issue in critical areas. The reinforcement member is cast into the housing component and at least partially surrounds the first and second bores, providing localized thermal stability where gear mounting occurs, while the rest of the housing maintains aluminum's lightweight properties

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If the engine housing component is made from aluminum, then weight is reduced, but thermal expansion causes increased backlash between meshing gears

Engineering Contradiction:
Improveweight of engine housingVSAvoidbacklash between gears
Core Design Contradiction:
Weight of moving objectVSObject-generated harmful factors

Solution Approach 1:

The invention explicitly addresses thermal expansion by incorporating a reinforcement member made of material having a lower coefficient of thermal expansion than the aluminum housing. This reinforcement member compensates for the thermal expansion of the aluminum housing, thereby preventing the increase in backlash between meshing gears that would otherwise occur due to thermal expansion

Inventive Principle:
Principle #37Thermal expansion

Solution Approach 2:

The engine housing assembly uses a composite structure combining aluminum housing component with a reinforcement member made of material having a lower coefficient of thermal expansion. This composite approach allows the housing to maintain lightweight aluminum construction while the reinforcement member compensates for thermal expansion differences, thereby preventing backlash between gears

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If a reinforcement member with different thermal expansion properties is added to the housing, then thermal expansion mismatch is reduced, but the device complexity increases

Engineering Contradiction:
Improvegear alignment precisionVSAvoidhousing structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The reinforcement member is cast into the aluminum housing component as an integrated assembly, merging two separate components (housing and reinforcement) into a single unified structure. This integration reduces assembly steps and simplifies the overall device complexity while maintaining the thermal expansion compensation functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The composite structure of aluminum housing with embedded reinforcement member creates a unified component that addresses thermal expansion issues. The reinforcement member is cast into the housing component, creating an integrated assembly that maintains structural integrity while compensating for thermal effects, thereby managing complexity through design integration rather than separate assemblies

Inventive Principle:
Principle #40Composite materials

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

The solution effectively reduces the difference in thermal expansion between the engine housing and gear wheels, minimizing backlash and wear, and maintaining efficient torque transfer and vibration balance.

Implementation Method 1

aluminium has a greater coefficient of thermal expansion than materials that have previously been used to manufacture components of engine assemblies. The greater coefficient of thermal expansion can be detrimental to the performance of some components within the engine assembly

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3677765B1Engine housing assemblies
Publication Date: 2023.02.22 FORD GLOBAL TECH LLC
  • EP3677765B1 patent drawingFigure 1
  • EP3677765B1 patent drawingFigure 2
  • EP3677765B1 patent drawingFigure 3

AI summary

An engine housing assembly is provided. The engine housing assembly comprises an engine housing component, the housing component at least partially defining a first bore for receiving a first shaft and at least partially defining a second bore for receiving a second shaft; and a reinforcement member cast into the housing, the reinforcement member having a lower coefficient of thermal expansion than the housing component, wherein the reinforcement member at least partially surrounds the first and second bores. A method of manufacturing the engine housing assembly is also provided.