Electric Machine Water Ingress Protection via Pressure Chamber
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Solution Overview
Problem
Electrical machines in vehicles, especially commercial ones, are vulnerable to water ingress, which can lead to temporary or complete disruption of electrical contact and corrosion, particularly affecting sliding contacts and slip rings.
Innovation Solution
The implementation of a pressure chamber within the electrical machine housing, pressurized with compressed air to create overpressure higher than the ambient pressure, protecting sensitive components like slip rings and converters, with control units managing air supply based on environmental parameters to prevent water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrical machine is designed to be splash-proof only, then the device complexity remains low, but the protection against water ingress is insufficient when the vehicle is surrounded by water
Solution Approach 1:
The housing is divided into multiple sealed pressure chambers, each containing specific water-sensitive devices. This segmentation allows targeted protection of critical components (slip rings, sliding contacts, electronic elements) without requiring the entire machine to be completely sealed, thus improving water protection while managing complexity through modular design.
Solution Approach 2:
Compressed air is introduced into the pressure chambers to create overpressure relative to the ambient water pressure. This pneumatic approach actively prevents water ingress by maintaining a pressure differential, providing reliable protection in submerged conditions without requiring complex mechanical seals or barriers.
2Reliability
If compressed air supply devices are added to maintain constant overpressure, then the protection against water ingress is improved, but the device complexity and cost increase
Solution Approach 1:
The invention utilizes the existing compressed air system already present in motor vehicles (intake tract, compressed air reservoir) to supply air to the pressure chambers. This multi-functional approach allows the vehicle's existing compressed air infrastructure to serve dual purposes: engine operation and water protection, eliminating the need for dedicated compressed air generation devices.
Solution Approach 2:
Instead of maintaining constant overpressure, the system uses periodic or conditional pressurization controlled by a control unit. The control unit activates compressed air supply only when water ingress risk is detected (via water sensors or based on environmental parameters), reducing the operational burden on the compressed air system while maintaining adequate protection during critical periods.
3Ease of operation
If the outlet opening cross section is enlarged, then the ventilation and moisture removal capability is improved, but the ability to maintain overpressure is reduced
Solution Approach 1:
The outlet opening cross-section is specifically dimensioned to create an optimal balance between ventilation capability and pressure retention. The opening size is calibrated as a critical parameter to allow sufficient moisture removal and air exchange while maintaining the necessary overpressure differential to prevent water ingress, achieving both ventilation and pressure maintenance requirements.
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
Effectively prevents water ingress and maintains functionality even when submerged, utilizing existing vehicle components for compressed air supply, ensuring reliable operation in wet conditions without constant overpressure.
Implementation Method 1
at least one device located in the housing of the electrical machine is arranged in at least one pressure chamber, which is preferably temporarily pressurized via a compressed air connection with an overpressure that is higher than the ambient pressure of the medium surrounding the electrical machine
Implementation Method 2
If the outlet opening is located in a lower outflow area of the pressure chamber, water can also automatically flow out of the outlet opening
Data Source
Figure 1~2
AI summary
The invention relates to an electric machine for a vehicle, in particular for a commercial vehicle, and a method for protection against water ingress for such a machine with a rotor (3) rotatably mounted on a shaft (2) and a stator (4) surrounding the rotor (3), wherein at least one device (8, 9) of the electric machine (1) is located in at least one pressure chamber (6, 7) which is subjected at least temporarily to an overpressure higher than the ambient pressure.