E-Axle Cooling Circuit Seal with Overflow Leak Diversion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electric axis modules face challenges in effectively sealing the cooling circuit, which can lead to coolant leakage into the power electronics cavity, potentially damaging semiconductor components.

Innovation Solution

A compact sealing arrangement is proposed, featuring a pipe-shaped component with two sealing elements, one of which includes an overflow opening in the housing wall, ensuring reliable sealing and preventing coolant ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing arrangement with multiple sealing elements is used in the cooling circuit, then the sealing reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple sealing functions into a single integrated sealing arrangement. The tubular insert incorporates both a first sealing element (O-ring) in a circumferential groove and a second sealing element (bead) on the end face, merging what would traditionally be separate sealing components into one unified structure that prevents coolant leakage at multiple locations simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing arrangement is segmented into distinct functional zones: the first sealing element addresses sealing at the circumferential interface between the tubular insert and housing, while the second sealing element handles the end face interface. This segmentation allows each sealing element to be optimized for its specific sealing location and pressure conditions.

Inventive Principle:
Principle #1Segmentation

2Reliability

If an overflow opening is provided between sealing elements, then the protection against coolant leakage is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveprotection against coolant leakageVSAvoidoverflow opening positioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The overflow opening is pre-positioned in the housing at a specific location between the two sealing elements. This preliminary placement ensures that if the first sealing element fails, coolant can immediately escape through the pre-positioned overflow opening before reaching the power electronics, providing a fail-safe mechanism without requiring complex real-time monitoring or adjustment systems.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the tubular insert is received in a recess of the housing, then the sealing effectiveness is improved, but the assembly difficulty increases

Engineering Contradiction:
Improvesealing effectivenessVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The second sealing element features a spherically curved sealing surface with a specific spherical radius. This curvature allows the bead to conform to the recess geometry and maintain uniform contact pressure across the sealing interface, improving sealing effectiveness while the spherical geometry facilitates smooth insertion and self-alignment during assembly, reducing assembly difficulty.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 provides a reliable two-way seal, ensuring the power electronics remain dry and functional, while simplifying assembly and reducing production costs by minimizing the number of components and potential damage during installation.

Implementation Method 1

a sealing arrangement (40) for a cooling circuit... comprising a tubular insert (48) on which a first sealing element (62) is arranged, wherein a second sealing element (64) is assigned to one of the end faces of the tubular insert (48)

Methodology Applied
Scientific EffectMechanical sealing:

Implementation Method 2

an overflow opening (56) is provided between the sealing elements (62, 64), wherein the tubular insert (48) is received in a recess (52) of a housing wall (22) and the overflow opening (56) is designed in the wall of the recess (52) of the housing (12)

Methodology Applied
Scientific EffectFluid flow diversion:

Data Source

PatentEP4401999B1Sealing arrangement in a cooling circuit of an electric drive axle module
Publication Date: 2025.05.14 ROBERT BOSCH GMBH
  • EP4401999B1 patent drawingFigure 1
  • EP4401999B1 patent drawingFigure 2~3
  • EP4401999B1 patent drawingFigure 4~5

AI summary

The invention relates to a seal arrangement (40) in the cooling circuit of an E-axle module (10) comprising at least one electric machine (14) and at least one power electronics system (24). The seal arrangement (40) comprises a tubular insert (48) on which a first sealing element (62, 72) is arranged and which has an associated further sealing element (64, 76, 80) on one of its end sides (96, 98). An overflow opening (56) is located between the sealing elements (62, 72, 64, 76, 80). The invention also relates to the use of the seal arrangement (40) in the cooling circuit between an electric machine (14) and a power electronics system (24) of an E-axle module (10) of an electrically driven vehicle.