EPS Breather Vent Layout for Waterproof Pressure Equalization
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Solution Overview
Problem
Existing electric power steering devices face challenges in maintaining waterproofness due to pressure differences caused by temperature changes, which can lead to deterioration of the waterproof structure, especially when exposed to environments with significant temperature variations.
Innovation Solution
A breathing device with a ventilator protruding from the electric power steering device, configured to provide ventilation between the inside and outside, is integrated into the device to enhance waterproofness by allowing air expansion and contraction while preventing water ingress, using a water-repellent filter and strategically positioning the ventilator to ensure effective ventilation and protection from submersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealed structure is used for complete waterproofness, then waterproofness is improved, but pressure differences cause structural deterioration
Solution Approach 1:
The patent applies a water-repellent filter that functions as a porous material, allowing air molecules to pass through while blocking water molecules. This resolves the contradiction by enabling the sealed structure to breathe (maintaining pressure balance) while still providing waterproof protection. The filter's porous nature permits gas permeability for pressure equalization during temperature changes, preventing structural deterioration.
Solution Approach 2:
The water-repellent filter acts as an intermediary component between the sealed interior and exterior environments. It mediates the interaction between pressure differences and waterproofing requirements by selectively permitting air flow while blocking water, thus protecting the sealed structure from pressure-induced deterioration while maintaining waterproofness.
2Object-affected harmful factors
If a filter is used for waterproofness, then protection against water spray is improved, but sufficient waterproofness cannot be maintained under large pressure differences
Solution Approach 1:
The patent changes the functional parameters of the filter by specifying it as water-repellent rather than simply porous. This parameter change enables the filter to differentiate between water molecules and air molecules, allowing it to block water spray while permitting air flow for pressure equalization. The water-repellent property maintains waterproofness even under pressure differences caused by temperature variations.
3Productivity
If the ventilator protrudes upward, then ventilation efficiency is improved, but water ingress risk increases
Solution Approach 1:
The water-repellent filter applied to the upward-protruding ventilator enables it to maintain high ventilation efficiency while preventing water ingress. The porous structure allows air to flow freely for efficient pressure equalization during temperature changes, while the water-repellent property blocks water molecules, thus resolving the contradiction between ventilation efficiency and water protection.
4Object-affected harmful factors
If the ventilator protrudes horizontally, then water ingress is reduced, but ventilation efficiency may be compromised
Solution Approach 1:
The water-repellent filter serves as an intermediary that enables the horizontally-protruding ventilator to achieve both water protection and ventilation efficiency. It mediates between the need to reduce water ingress exposure and the requirement for effective ventilation, allowing air to pass through while blocking water, thus resolving the contradiction.
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 breathing device improves waterproofness by managing pressure differences and preventing structural deterioration, ensuring the electric power steering device remains functional even in environments with extreme temperature fluctuations and potential water exposure.
Implementation Method 1
This filter is water-repellent, and thus is impermeable to water but permeable to air
Implementation Method 2
the air inside the device expands due to generation of heat from the rotating machine or the control unit, and the air inside the device shrinks when the device is cooled thereafter
Data Source
AI summary
A breathing device includes a ventilator, which is arranged on an end surface of the control unit provided with a connector on an opposite side of an output shaft of a rotating machine so as to protrude from an inside of the electric power steering device toward an outside of the electric power steering device, and is configured to provide a breathing action through ventilation between the inside and the outside. The ventilator protrudes in a horizontal direction or upward with respect to the horizontal direction.