Electric Power Steering ECU Layout for Cooling and Redundancy

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Solution Overview

Problem

Existing electric power steering systems lack a compact, low-cost, and easy-to-assemble design for their electronic control units, which are prone to overheating due to inefficient heat dissipation.

Innovation Solution

The electronic control unit is designed with two power boards of different lengths connected to a connector plate, allowing for a compact layout and improved heat dissipation through a heat sink sandwiched between them, along with redundant power supply to ensure reliability and easy assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single power board is used in the electronic control unit, then the device complexity is reduced, but the reliability decreases due to lack of redundancy

Engineering Contradiction:
Improvepower supply reliabilityVSAvoidcontrol unit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements redundant power boards (first and second power boards) that are prepared in advance to compensate for potential failures. If one power board fails, the other can immediately take over, providing beforehand cushioning against power supply failures and ensuring continuous operation of the electric power steering system.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies different connector lengths (first power connector shorter than second power connector) to different power boards based on their specific positions and requirements. This local differentiation allows each power board to be optimally configured for its role while maintaining overall system redundancy, resolving the contradiction between reliability and complexity.

Inventive Principle:
Principle #3Local quality

2Temperature

If power boards are arranged far apart for heat dissipation, then temperature control improves, but the volume of the electronic control unit increases

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcontrol unit volume
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent places the first and second power boards on opposite sides of the heat sink, nesting them together with the heat sink in between. This nested arrangement allows the power boards to be closely positioned for compact volume while the heat sink effectively dissipates heat from both boards, resolving the contradiction between temperature control and volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The heat sink acts as an intermediary component between the two power boards, positioned in between them to facilitate heat dissipation. This intermediary structure enables the power boards to be arranged close together for compact design while maintaining effective thermal management through the heat sink's mediating heat dissipation function.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If different length connectors are used for power boards, then ease of assembly improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improveassembly easeVSAvoidconnector length precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent deliberately uses asymmetric connector lengths (first power connector shorter than second power connector) to match the different positions and requirements of the two power boards. This asymmetric design simplifies assembly by providing built-in positioning guidance and preventing incorrect installation, while the manufacturing precision requirements are managed through standardized connector design and quality control processes.

Inventive Principle:
Principle #4Asymmetry

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 design achieves a compact, low-cost, and reliable electric power steering system with effective heat dissipation and redundant power supply, preventing overheating and ensuring stable operation even in case of power board failure.

Implementation Method 1

a heat sink may be provided inside of the electronic control unit and arranged in thermal contact with a housing of the electric power steering system or electric motor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4146522B1Electronic control unit and electric power steering system
Publication Date: 2025.08.27 HELLA GMBH & CO KGAA
  • EP4146522B1 patent drawingFigure 1
  • EP4146522B1 patent drawingFigure 2
  • EP4146522B1 patent drawingFigure 3

AI summary

The invention relates to an electronic control unit (100) for an electric power steering system (200), the electric power steering system (200) comprising a housing (210) and an electric motor, the electronic control unit (100) being configured to be arranged inside the housing (210) and to be electrically connected to the electric motor, whereby the electronic control unit (100) comprises a first power board (30) having a first electric motor connector (80) for electric connection with the electric motor, a second power board (40) having a second electric motor connector (90) for electric connection with the electric motor, and whereby a connector plate (10) of the electronic control unit (100) is electrically connected by means of at least one plug connector (11) of the connector plate (10) to the first power board (30) via at least one first power connector (17) and to the second power board (40) via at least one second power connector (16), wherein the at least one first power connector (17) is shorter than the at least one second power connector (16). The invention further relates to an electric power steering system (200).