Waterproof Case Protection Piece Protrusion Water Ingress

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Solution Overview

Problem

Conventional waterproof cases for motor vehicle engine rooms are prone to water ingress during car washing, leading to potential electrical component failure due to deformation of the lower cover's peripheral wall under water pressure, which existing protection pieces cannot reliably prevent.

Innovation Solution

A waterproof case design featuring a protection piece with a protrusion and a through hole, where the lower end surface of the protrusion covers the upward opening between the protection piece and the case body's peripheral wall, and the through hole directs any entering water outwards, combined with a thick portion around the hole to prevent welding line formation during injection molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a protection piece is added to prevent inward deformation of the lower cover's peripheral wall, then the resistance to water pressure is improved, but a new space is created between the protection piece and case body that allows water to enter along path Y3

Engineering Contradiction:
Improvewater ingress preventionVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention transitions from a two-dimensional planar protection approach to a three-dimensional solution by adding a protrusion that extends vertically from the case body. This protrusion fills the gap created by the protection piece, blocking water ingress path Y3 through the third dimension (vertical height), thereby resolving the contradiction between protection effectiveness and structural simplicity

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

Solution Approach 2:

The protrusion acts as an intermediary element between the case body and the protection piece. It fills the space between these two components, preventing water from entering through the gap while maintaining the protective function against water pressure. This intermediary structure resolves the contradiction by eliminating the harmful space without compromising the protection mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the peripheral wall of the lower cover is allowed to deform inward under water pressure, then the structure remains simple, but water can enter the case through the widened space between the peripheral wall and protection piece

Engineering Contradiction:
Improvestructural simplicityVSAvoidwaterproofing reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The protrusion is designed to preemptively block the water ingress path before water can exploit the gap between the protection piece and case body. By positioning the protrusion to extend into the space where water would flow along path Y3, the design prevents the harmful effect before it can occur, maintaining both structural simplicity and waterproofing reliability

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The protection piece and protrusion are configured to create a pre-assembled protective structure that anticipates water pressure effects. The protrusion is positioned in advance to block potential water ingress paths, ensuring waterproofing reliability without requiring complex active response mechanisms

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2404787B1Waterproof case
Publication Date: 2014.03.19 YAZAKI CORP
  • EP2404787B1 patent drawingFigure 1
  • EP2404787B1 patent drawingFigure 2
  • EP2404787B1 patent drawingFigure 3

AI summary

There is provided a waterproof case (1) which prevents ingress of water into the waterproof case (1) through a protection piece, including a case body (3) formed into a rectangular tube-like shape with a peripheral wall (42) thereof and a lower cover (4) having a bottom wall covering a lower opening of the case body (4) and a peripheral wall (42) extending from the bottom wall. The peripheral wall (31) of the body case (3) is placed so as to cover the peripheral wall (42) of the lower cover (4). The protection piece (43 ) is provided at the peripheral wall (42) of the lower cover (4) so as to sandwich the peripheral wall (31) of the case body (3) with the peripheral wall (42) of the lower cover (14) to prevent the deformation of the peripheral wall (42) of the lower cover (4). There is also provided a protrusion protruding from a surface of the peripheral wall of the case body on which the protection piece is placed.