Axle Drive Train Venting With Separator Cartridge for Oil Leakage

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Solution Overview

Problem

Existing electrically operable axle drive trains face challenges in ensuring safe ventilation without oil leakage and pressure equalization while maintaining efficient cooling and lubrication, particularly due to high speeds and temperature fluctuations, which can lead to oil foam and mist formation.

Innovation Solution

An electrically operable axle drive train with a ventilation channel opposite the direction of gravity, incorporating a separator cartridge made of plastic, reduces hydraulic fluid flow rate and prevents leakage by returning it to the transmission assembly, while allowing air to escape for pressure compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ventilation channel is provided to equalize pressure in the transmission compartment, then pressure equalization and air exchange are improved, but hydraulic fluid leakage and oil mist formation occur

Engineering Contradiction:

Improvepressure equalizationVSAvoidhydraulic fluid leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A separator cartridge is introduced as an intermediary component in the ventilation channel. This cartridge contains a separator element that intercepts hydraulic fluid droplets and oil mist from the ventilation airflow, allowing air to pass through while returning liquid fluid to the transmission compartment through a return opening. This resolves the contradiction by enabling pressure equalization while preventing harmful fluid leakage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful component (hydraulic fluid and oil mist) is extracted from the ventilation airflow using the separator element. The separator element removes liquid fluid droplets and condenses oil mist from the air stream, separating these harmful substances from the beneficial ventilation function. This allows the ventilation channel to maintain pressure equalization without releasing harmful fluids to the environment.

Inventive Principle:

Principle #2Taking out (Extraction)

2Temperature

If high cooling capacities are provided for the electric machine, then thermal management is improved, but oil foam and mist formation increase

Engineering Contradiction:

Improvecooling capacityVSAvoidoil foam and mist

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The separator cartridge converts the harmful oil mist and foam into a beneficial recycling system. The separator element captures oil mist droplets from the ventilation channel, and the collected fluid is returned to the transmission compartment through the return opening. This transforms what would be harmful emissions into a resource that can be reused for lubrication and cooling, while still maintaining the high cooling capacities needed for thermal management.

Inventive Principle:

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

3Object-generated harmful factors

If a separator cartridge is inserted in the ventilation channel, then hydraulic fluid leakage is reduced, but device complexity increases

Engineering Contradiction:

Improvehydraulic fluid leakageVSAvoidventilation system complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The separator cartridge is designed as a separate, modular component that can be independently manufactured and installed in the ventilation channel. This segmentation allows the complex separation function to be isolated in a single replaceable unit, simplifying the overall system architecture. The cartridge contains the separator element and return mechanism as integrated sub-components, making the complex function manageable and maintainable without significantly increasing overall device complexity.

Inventive Principle:

Principle #1Segmentation

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 prevents hydraulic fluid leakage and ensures sufficient lubrication levels, reduces environmental impact, and maintains efficient ventilation and pressure equalization, enhancing operational safety and cost-effectiveness.

Implementation Method 1

a ventilation channel extending through the transmission housing, opposite the direction of gravity, connects the transmission assembly within the transmission housing to the environment

Methodology Applied

Scientific EffectGravity: Gravitation

Implementation Method 2

ventilation or pressure equalization of the engine and/or transmission compartment with the environment must usually be provided

Methodology Applied

Scientific EffectPressure equalization: Pressure Gradient

Data Source

PatentUS12540666B2Electrically operable axle drive train

Publication Date: 2026.02.03 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

An electrically operable axle drive train for a motor vehicle, comprising an electric machine accommodated in a motor housing, and a transmission assembly accommodated in a transmission housing, wherein the electric machine and the transmission assembly form a structural unit, and a ventilation channel extending through the transmission housing, opposite the direction of gravity, connects the transmission assembly within the transmission housing to the environment, wherein a separator cartridge designed as a separate component from the transmission housing is introduced into the ventilation channel and is configured such that it reduces the flow rate of a hydraulic fluid in the ventilation channel.