Fluid Pump ECU Housing for Direct PCB Oil Cooling

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Solution Overview

Problem

Existing electric fluid pumps, particularly those with brushless DC motors, face challenges in efficiently dissipating heat from non-uniformly distributed hot spots on the PCB, require costly aluminum heat sinks, and struggle with sealing and electrical connections while aiming for a cost-effective design with minimal parts and reduced size.

Innovation Solution

The design integrates a PCB with SMT components sealed against fluid using a single sealant, allowing direct cooling by the fluid, and uses SMT contacts for electrical connections without through-holes, reducing the need for complex seals and multiple parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If aluminum heat sinks with thermal paste are used to cool the PCB, then heat dissipation capability is improved, but manufacturing cost increases and device complexity increases

Engineering Contradiction:
ImprovePCB heat dissipationVSAvoidmanufacturing cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention extracts the thermal paste and complex heat sink structure, replacing them with direct fluid-to-PCB contact through openings in the housing. The cooling function is achieved by allowing the pumped fluid to directly touch the PCB underside, eliminating the need for thermal interface materials and complex aluminum heat sink assemblies.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The PCB itself serves as the intermediary between the hot spots and the cooling fluid. By creating openings in the housing that allow fluid to reach the PCB underside, the PCB becomes both the electronic carrier and the heat transfer surface, eliminating the need for separate heat sink components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If aluminum heat sinks and reliable seals are used to separate fluid from electronic components, then cooling performance and reliability are improved, but manufacturing cost increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealant adhesive serves multiple functions simultaneously: it bonds the PCB to the housing, provides sealing against fluid infiltration, and enables thermal transfer. This multi-functionality eliminates the need for separate sealant applications and reduces the total number of components and manufacturing steps.

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

Solution Approach 2:

The invention merges the bonding function and sealing function into a single sealant adhesive layer. Instead of using separate adhesives and sealants, one material performs both tasks, reducing part count and simplifying the manufacturing process while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If through-holes are created in the circuit board for electrical connections, then electrical connectivity is achieved, but sealing capability deteriorates

Engineering Contradiction:
Improvesealing capabilityVSAvoidelectrical connectivity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention replaces traditional mechanical through-hole mounting with SMT (Surface Mount Technology) contacts. The electrical connections are made through surface-mounted components that pass through the housing openings rather than requiring holes through the PCB itself, maintaining both sealing and connectivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If multiple separate seals and complex sealing structures are used to seal housing parts and PCB, then sealing reliability is improved, but device complexity increases

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

Solution Approach 1:

The sealant adhesive is designed to perform multiple sealing functions in one application: sealing the PCB against fluid, sealing the housing joints, and providing environmental protection. This universal sealing approach reduces the number of separate seal components and simplifies the overall sealing structure.

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

Solution Approach 2:

The invention combines multiple sealing functions into a single sealant material applied in one process step. Instead of using separate seals for PCB mounting and housing joints, the same sealant adhesive performs both sealing tasks, reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

5Temperature

If traditional cooling methods with separate heat sinks are used, then heat dissipation is achieved, but the pump size and weight increase

Engineering Contradiction:
Improveheat dissipationVSAvoidpump weight
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The invention extracts the separate heat sink component entirely, replacing it with direct fluid-to-PCB cooling. By removing the aluminum heat sink structure and thermal paste, the overall pump weight and size are reduced while maintaining effective heat dissipation through the pumped fluid itself.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The pumped fluid serves a dual purpose: it performs the primary cooling function for the motor and electronics while also providing the cooling effect for the PCB. The system uses its own operating fluid for cooling, eliminating the need for additional cooling components and reducing overall system weight.

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 approach enhances heat dissipation efficiency, reduces part costs, and allows for a compact design using less expensive materials like plastic, while maintaining effective sealing and electrical connectivity.

Implementation Method 1

the PCB being arranged on the lower part of the housing with a sealant adhesive

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

Fluid or oil can reach the underside of the PCB through the at least one opening. This enables direct cooling of the PCB by the fluid

Methodology Applied
Scientific EffectConvection cooling: Convection

Implementation Method 3

the control unit's circuit board is mounted to a heat sink with good thermal conductivity, such as aluminum, which transfers heat to the ambient air or the oil being pumped

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the circuit board has contact elements on the side facing away from the housing cover for contact with contact elements emanating from the electric motor, which extend through the at least one opening in it

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4453425B1Housing device for a fluid pump
Publication Date: 2026.02.11 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4453425B1 patent drawingFigure 1
  • EP4453425B1 patent drawingFigure 2
  • EP4453425B1 patent drawingFigure 3

AI summary

The present invention relates to a housing device (10) for an electric fluid pump, in particular a cooling pump or oil pump, comprising a pump (20) having a pump housing (150), comprising an electric motor (30) having a motor housing (90) and comprising an electronics module (40) having an ECU housing (50, 60) with a housing. The latter consists of a housing body cover and a housing body lower part (60), and a printed circuit board (170) arranged therein. The printed circuit board (170) has an electrical circuit arrangement (220) on one side and is arranged on the housing body lower part (60) using a sealing adhesive (180). At least one opening (190) through which oil can pass is provided in the housing body lower part (60), and the housing body cover (50) and the housing body lower part (60) are sealingly fitted to each other.