Steering Sensor Housing Seal Structure Against Moisture Ingress

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Solution Overview

Problem

The existing housing structures for steering apparatus sensors are prone to infiltration of rainwater and saltwater, leading to corrosion and moisture ingress, which compromises the integrity of the sensors.

Innovation Solution

A housing structure comprising a first and second housing member with seal holding portions and a recessed space, utilizing a cylindrical shape and annular seal members to create a liquid-tight seal, with the second housing member made of resin and the first of aluminum alloy, to prevent moisture infiltration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat plate sensor cover is fixed to the sensor housing with tight contact, then the housing structure is simple and easy to manufacture, but rainwater and saltwater infiltrate into the narrow gap between contact surfaces by capillary phenomenon causing corrosion

Engineering Contradiction:

Improvehousing structure simplicityVSAvoidmoisture infiltration and corrosion

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the flat plate cover with a domed cover having a curved surface. This curvature eliminates narrow gaps between the cover and housing, preventing capillary infiltration of rainwater and saltwater while maintaining structural integrity and sealing effectiveness.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces a protrusion on the cover that extends into the housing interior, creating a new spatial dimension for sealing. This protrusion structure provides additional sealing contact surfaces and prevents water infiltration from multiple angles, enhancing protection against moisture.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the housing is disposed on the bottom side of the vehicle for sensor protection, then the sensors are protected from external damage, but the housing is exposed to rainwater and saltwater infiltration

Engineering Contradiction:

Improvesensor protectionVSAvoidexposure to rainwater and saltwater

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The domed cover's curved surface prevents water accumulation and facilitates water runoff, reducing the housing's exposure to rainwater and saltwater infiltration while maintaining sensor protection in the bottom-side position.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The protrusion structure acts as an intermediary element between the cover and housing interior, creating a barrier that prevents direct water infiltration while allowing the housing to remain in its protective bottom-side position.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Duration of action of stationary object

If multiple times of salt water infiltration occur, then salinity concentration becomes high and corrosion of contact surfaces proceeds, but the housing structure remains unchanged

Engineering Contradiction:

Improvehousing durabilityVSAvoidcorrosion from salt water accumulation

Core Design Contradiction:

Duration of action of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The curved domed cover prevents capillary action and water accumulation, eliminating the condition for salt water infiltration to occur repeatedly. This protects contact surfaces from corrosion and extends housing durability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent converts the potential harmful effect of water infiltration into a beneficial sealing structure where the domed shape and protrusion create natural water barriers, preventing salt water accumulation and corrosion while enhancing the housing's protective function.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 proposed housing structure effectively suppresses the infiltration of rainwater and saltwater, enhancing the sealing performance and preventing corrosion, thereby ensuring the longevity and reliability of the sensors.

Implementation Method 1

the second housing seal member holding portion holds an annular seal member between the first housing seal member holding portion and the second housing seal member holding portion in a radial direction to a rotation axis of the steering shaft

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

rainwater or salt water infiltrates into a narrow gap between contact surfaces of the sensor cover and the sensor housing by a capillary phenomenon

Methodology Applied

Scientific EffectCapillary phenomenon prevention: Capillary Action

Data Source

PatentUS11293787B2Housing structure for steering apparatus

Publication Date: 2022.04.05 ASTEMO LTD

AI summary

In a housing structure for a steering apparatus, a first seal holding portion 50B is formed to a first sensor housing 50 and a second seal holding portion 51B is formed to a second sensor housing 51, and in a state in which the first sensor housing 50 is combined with the second sensor housing 51, a seal ring 55 is held between the first seal holding portion 50B and the second seal holding portion 51B, and recessed space parts 56A to 56D for storing moisture is formed on the radial outer side of the second seal holding portion 51B when viewed in the rotation axis of a steering shaft 4.