Axle Lubricant Control Using Torque-Based Sump Regulation

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Solution Overview

Problem

Conventional axle assemblies face inefficiencies due to excessive lubricant volume leading to windage, increased operating temperatures, and reduced reliability, especially in torque-intensive operations and cold weather conditions, where reduced lubricant volume fails to adequately reduce friction and disperse heat effectively.

Innovation Solution

An active lubricant management system that includes a torque sensor to determine torque loads, a controller to adjust the valve position, and a reservoir system outside the carrier housing, allowing for controlled lubricant flow between the sump and reservoir, optimizing lubricant levels based on operational conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the volume of lubricant in the sump is increased, then the effectiveness of reducing friction and dispersing heat is improved, but windage and parasitic drag increase

Engineering Contradiction:
Improveeffectiveness of reducing frictionVSAvoidwindage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system dynamically adjusts lubricant volume in the sump based on operating conditions. A valve controlled by a torque sensor and controller allows lubricant to flow between the reservoir and sump, transitioning the system from a static to a dynamic state where lubricant volume adapts to match actual operational needs, reducing windage during low-torque conditions while maintaining adequate lubrication during high-torque operations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lubricant management system operates periodically by sensing torque conditions and actuating the valve to transfer lubricant between the reservoir and sump. The torque sensor continuously monitors load conditions, and the controller periodically adjusts valve position to maintain optimal lubricant volume, creating a cyclic adjustment pattern that responds to varying operational demands

Inventive Principle:
Principle #19Periodic action

2Loss of energy

If the volume of lubricant in the sump is reduced, then windage is decreased, but the ability to reduce friction and disperse heat during torque intensive operation is compromised

Engineering Contradiction:
ImprovewindageVSAvoidability to reduce friction
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system transitions from a static fixed-volume lubricant system to a dynamic adjustable-volume system. The valve mechanism allows continuous adjustment of lubricant volume between minimum and maximum levels based on real-time torque sensing, enabling the system to optimize the balance between reducing windage and maintaining adequate lubrication for friction reduction

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The torque sensor provides continuous feedback about the actual load conditions to the controller. This feedback loop enables the system to make informed decisions about lubricant volume adjustment, ensuring that sufficient lubricant is available in the sump when torque-intensive operations are detected, while allowing lubricant volume to be reduced during low-torque conditions

Inventive Principle:
Principle #23Feedback

3Temperature

If the volume of lubricant in the sump is increased, then heat dispersion capability is improved, but operating temperatures increase due to reduced viscosity effectiveness in cold weather

Engineering Contradiction:
Improveheat dispersion capabilityVSAvoidviscosity effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The system dynamically adjusts lubricant volume based on thermal and viscosity conditions. During cold weather operation, the valve restricts lubricant flow to the sump, maintaining a smaller volume that preserves viscosity effectiveness. When operating temperatures rise and heat dispersion becomes critical, the valve opens to allow greater lubricant volume in the sump, enhancing heat absorption and dispersion capability

Inventive Principle:
Principle #15Dynamics

4Reliability

If an active lubricant management system with torque sensor and valve control is implemented, then lubricant level optimization is achieved, but device complexity increases

Engineering Contradiction:
Improvelubricant level optimizationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lubricant management system is largely self-regulating, using the torque sensor to automatically detect load conditions and trigger appropriate valve adjustments without requiring external intervention or complex control algorithms. The system serves itself by using its own operational parameters (torque) to control its own lubricant distribution, reducing the need for additional sensors or complex control logic

Inventive Principle:
Principle #25Self-service

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 system effectively manages lubricant levels, reducing windage, maintaining component reliability, and preventing premature degradation, while allowing for efficient heat dissipation and noise reduction across varying operational conditions.

Implementation Method 1

gear teeth of said ring gear are configured to carry lubricant from the lubricant sump and to fling the lubricant into the lubricant catch

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a sump in the carrier housing contains lubricant to reduce friction between surfaces including, but not limited to, the pinion gear and ring gear

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 3

The lubricant may also disperse heat generated between the components of the axle assembly

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3330574B1Axle assembly
Publication Date: 2023.03.29 DANA HEAVY VEHICLE SYSTEMS GROUP LLC
  • EP3330574B1 patent drawingFigure 1
  • EP3330574B1 patent drawingFigure 2
  • EP3330574B1 patent drawingFigure 3

AI summary

An apparatus for regulating lubricant having a carrier housing including a lubricant sump. A ring gear disposed within the carrier housing, wherein the ring gear is partially disposed in the lubricant sump. A lubricant catch is disposed in the carrier housing, and a reservoir is disposed outside of the carrier housing. A first conduit is disposed between the lubricant catch and the reservoir. A second conduit is disposed between the reservoir and the lubricant sump. A valve is in fluid communication with the reservoir and the lubricant sump.