Electric Machine Venting Chamber for Pressure Equalization
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Solution Overview
Problem
Existing electrical machines for motor vehicles face challenges in pressure equalization due to temperature changes, which can lead to undesirable pressure changes and the ingress of foreign bodies like water, water vapor, and oil mist, especially when using oil bath lubrication and cooling systems, and existing solutions either require maintenance, are prone to oil clogging, or risk water ingress.
Innovation Solution
A venting element with a large-volume collecting chamber and strategically positioned outlets, connected to both the interior and external environment, prevents foreign bodies from entering the machine housing by creating a pressure equalization system that allows air to escape and prevents water and oil mist from entering the external environment, while being maintenance-free and adaptable in design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple air vent with rain cover and strainer is used for pressure equalization, then the structure is simple and easy to install, but there is a risk of pressurized water entering the interior of the electrical machine
Solution Approach 1:
The venting device employs a nested structure where the collecting chamber is integrated into the housing, and the outlet is positioned within the oil bath lubrication system. This nested arrangement allows the outlet to be surrounded by oil, creating a natural barrier against water ingress while maintaining a compact and simple overall structure.
Solution Approach 2:
The oil bath lubrication system serves as an intermediary medium between the external environment and the electrical machine interior. The outlet discharges into the oil bath, where oil acts as a barrier to prevent water and water vapor from entering the machine, while still allowing pressure equalization through the oil medium.
2Productivity
If the outlet is positioned to allow pressure equalization, then air can escape effectively, but oil mist and water vapor can contaminate each other in the environment
Solution Approach 1:
The invention separates the functions of pressure equalization and environmental discharge. The outlet extracts the pressure equalization function by providing a dedicated path for air to escape into the oil bath, while the sealed housing structure prevents oil mist and water vapor from mixing in the external environment. The oil bath contains the oil mist, and the sealed structure contains the water vapor.
Solution Approach 2:
The oil bath lubrication system acts as a disposable or replaceable medium that absorbs the harmful effects of oil mist and water vapor interaction. Instead of trying to prevent all contamination, the system allows controlled interaction within the oil bath, which can be periodically replaced or maintained, simplifying the overall design while protecting the critical electrical components.
3Reliability
If a membrane solution is used for pressure equalization, then it can prevent water ingress, but oil droplets can clog micropores in the membrane over time requiring maintenance
Solution Approach 1:
Instead of using a membrane with micropores that can clog, the invention creates a functional copy of the protection mechanism by using the oil bath itself as the barrier. The oil layer on the surface of the bath prevents water ingress without requiring porous structures, eliminating the clogging problem while maintaining the protective function.
Solution Approach 2:
The oil bath lubrication system serves multiple functions simultaneously: it provides lubrication, cooling, and water protection. The oil naturally separates from water due to density differences, with oil floating on top to form a protective barrier. This self-organizing behavior provides continuous protection without requiring active maintenance or replacement of filtering components.
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 solution effectively reduces the ingress of foreign bodies and maintains a clean environment within the electrical machine, ensuring reliable operation and easy installation, with the collecting chamber's design and multiple outlets preventing water and oil mist from entering the internal components.
Implementation Method 1
The venting element prevents foreign bodies from the external environment of the electrical machine that have penetrated into the collecting chamber from entering the interior of the machine housing via the inlet of the venting element
Implementation Method 2
The venting element connects the interior with the external environment of the electrical machine in such a way that air escapes from the interior via the inlet, the collecting chamber and the at least one outlet into the external environment when the internal pressure is higher than a prevailing external pressure in the external environment
Implementation Method 3
If the electrical machine has an oil bath for lubricating and/or cooling its components
Implementation Method 4
If the electrical machine has an oil bath for lubricating and/or cooling its components
Data Source
AI summary
An electrical machine has a machine housing accommodating a rotor, a stator, and an output shaft. A venting element has a collecting chamber, an inlet, and at least one outlet, where the inlet is connected to the interior space of the housing, within which air can expand and increase in pressure when the electrical machine heats up during operation. The outlet(s) of the venting element connects to an external environment. The collecting chamber is between the inlet and the outlet(s) and is connected via the inlet to the interior of the housing and via the at least one outlet to the environment. The venting element connects the interior to the environment so that air can escape from the interior via the inlet, the collecting chamber, and the outlet(s) to the environment when the internal pressure is higher than the pressure of the external environment.