Encapsulated E-Axle Brake Cooling via Fluid Convection

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Solution Overview

Problem

Current electric vehicle braking systems with open air-cooled friction elements face issues such as corrosion, reduced braking effectiveness in wet conditions, fine dust emissions, inefficient thermal management, and the need for separate parking brakes due to environmental exposure and design limitations.

Innovation Solution

An e-axle module with integrated, encapsulated brakes cooled by a fluid cooling system, where the brakes are either structurally integrated into the e-machine or transmission, allowing for shared thermal management with the e-machine and transmission, and eliminating the need for separate parking brakes through a spring-actuated mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If open air-cooled friction elements are used for braking, then cooling efficiency is improved, but corrosion and environmental damage occur due to exposure

Engineering Contradiction:
Improvebrake cooling efficiencyVSAvoidcorrosion and environmental damage
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent combines the brake system with the e-machine housing, integrating the brake into the enclosed housing structure. This merging allows the brake to benefit from the housing's protective enclosure while maintaining cooling capability through integrated cooling channels in the housing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing acts as an intermediary between the brake and the external environment. It provides a protective barrier that shields the brake from corrosion and environmental damage while allowing thermal energy to be transferred to the cooling fluid circulating through the housing's cooling channels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If open air-cooled friction elements are used, then thermal management is simplified, but fine dust emissions and water film problems increase

Engineering Contradiction:
Improvethermal management simplicityVSAvoidfine dust emissions and water film problems
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The brake cooling system is merged with the e-machine cooling system, using the same housing and cooling fluid circulation. This integration eliminates the need for separate air cooling pathways that would generate dust emissions and allow water film formation, while maintaining effective thermal management.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If separate braking systems are used for drive and brake functions, then functional independence is improved, but system complexity and development costs increase

Engineering Contradiction:
Improvefunctional independenceVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the brake system with the e-machine and transmission into a single integrated e-axle module. The brake is structurally integrated into the housing, sharing common components such as the cooling system, housing structure, and control electronics, thereby reducing overall system complexity while maintaining functional independence through controlled integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing serves multiple functions: it encloses and protects the e-machine, provides structural support, acts as a heat sink with integrated cooling channels, and houses the brake system. This multi-functionality reduces the need for separate components and systems, lowering complexity while maintaining functional independence.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Ease of manufacture

If open air-cooled brakes are used, then manufacturing simplicity is improved, but additional parking brake systems are required

Engineering Contradiction:
Improvebrake system manufacturing simplicityVSAvoidadditional parking brake requirement
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The parking brake function is merged with the service brake system by integrating both functions into the same brake mechanism within the enclosed housing. The spring-actuated brake can serve dual purposes: as a service brake during operation and as a parking brake when engaged, eliminating the need for a completely separate parking brake system.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enhances braking reliability, reduces environmental impact, optimizes thermal management, and integrates braking functions within the e-axle module, saving development and production costs while providing efficient and dynamic wheel torque interventions.

Implementation Method 1

the integrated, cooled brake is now cooled simultaneously with the e-machine and transmission by cooling fluid cooling

Methodology Applied
Scientific EffectFluid cooling: Convection

Implementation Method 2

frictional heat is always lost, even if it would be valuable for battery heating or air conditioning

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentEP3597463B1E-axle module
Publication Date: 2022.03.16 ROBERT BOSCH GMBH
  • EP3597463B1 patent drawingFigure 1~2
  • EP3597463B1 patent drawingFigure 3.1~3.2
  • EP3597463B1 patent drawingFigure 4

AI summary

The invention relates to an e-axle module (10) with at least one electric motor (12, 14, 96) integrated therein, which drives one or both wheels (20) mounted on the e-axle module (10), and with a transmission (30, 68, 74). The e-axle module (10) has at least one brake (24, 42) integrated therein, which is structurally integrated into the at least one electric motor (12, 14, 96) or the transmission (30, 68, 74).