ECU Base Plate Drainage Structure for Waterproof Connector Mounting

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Solution Overview

Problem

Conventional electronic control units (ECUs) for vehicles, particularly airbag ECUs, face challenges in meeting stringent waterproof standards due to gaps between the housing and electrical connector, leading to water ingress and potential failure, especially when the vehicle is inclined, which increases the risk of liquid splashes affecting the ECU's operation.

Innovation Solution

The ECU design incorporates a base plate with a load-bearing area and mounting area featuring guide holes, a rib structure, and protruding mounting bosses to create a clearance-fitting assembly that directs water away from the printed circuit board, combined with a housing and shielding portions to enhance waterproofing, allowing effective drainage and protection from splashes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the ECU is designed in an open manner with gaps between housing and electrical connector, then manufacturing is easier and cost is lower, but waterproof performance deteriorates and water ingress occurs

Engineering Contradiction:
Improvemanufacturing easeVSAvoidwaterproof performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The base plate is divided into distinct functional areas: a load-bearing area with mounting bosses for structural support, and a mounting area with guide holes for water drainage. This segmentation allows each area to optimize its function while maintaining overall manufacturability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guide holes act as intermediary elements that provide a controlled path for water to drain away from the electrical connector and printed circuit board, preventing direct water ingress while maintaining the open design structure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sealing reinforcement is added to improve waterproofing, then waterproof performance improves, but manufacturing complexity increases and production cycle time extends

Engineering Contradiction:
Improvewaterproof performanceVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The drainage function is extracted from the sealing structure itself and implemented through separate guide holes in the base plate. This eliminates the need for complex sealed channels while achieving the same water protection goal

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The open structure with guide holes allows water to naturally drain away from sensitive components through gravity and capillary action, eliminating the need for active pumping or complex mechanical sealing systems

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If the base plate length is increased to meet mounting hole requirements, then mounting stability improves, but the distance between electrical connector and base plate increases making waterproofing more difficult

Engineering Contradiction:
Improvemounting stabilityVSAvoidwaterproof performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The solution addresses the waterproofing challenge not by shortening the base plate (one-dimensional approach), but by creating a three-dimensional drainage pathway through guide holes that redirect water flow away from the electrical connector regardless of plate length

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 significantly improves the ECU's waterproof performance, enabling it to maintain operation even under IPX52 testing conditions by effectively draining water and preventing ingress, thus enhancing service life and precision while reducing costs compared to conventional reinforcement methods.

Implementation Method 1

the guide holes are configured to collectively occupy an area of at least 20 square millimeters, allowing the electronic control unit, via the guide holes, to maintain a guided flow rate of 77.8 milliliters / minute when tilted 30 degrees in the direction in which the opening is opened

Methodology Applied
Scientific EffectGravity-driven drainage: Gravitation

Data Source

PatentEP4415491A1Electronic control unit
Publication Date: 2024.08.14 ROBERT BOSCH GMBH
  • EP4415491A1 patent drawingFigure 1
  • EP4415491A1 patent drawingFigure 2A
  • EP4415491A1 patent drawingFigure 2B

AI summary

The present disclosure relates to an electronic control unit, comprising a base plate, wherein comprises a load-bearing area and a mounting area provided on a side of the load-bearing area, with at least one guide hole penetrating the base plate provided in the mounting area; a housing mounted on the load-bearing area of the base plate, wherein comprises a top wall and side walls extending downward from the edge of the top wall and continuously disposed around the top wall, with the top wall and the side walls collectively defining the accommodating space of the housing; a printed circuit board housed in the accommodating space between the base plate and the housing; and an electrical connector electrically connected to the printed circuit board, which is exposed through an opening provided on one of the side walls and is positioned above the guide holes. The electronic control unit of the present disclosure has enhanced waterproof capabilities that are capable of effectively preventing water from entering the interior of the electronic control unit, thereby improving the service life and operating precision of the electronic control unit.