Electric Motor Cooling Fan Segmentation for Mass Reduction
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Solution Overview
Problem
Conventional electric traction motor cooling fans are heavy due to the need for high mechanical strength, leading to reduced aeraulic performance and increased noise, while also being subjected to mechanical stresses.
Innovation Solution
A cooling device with a separate fan and support plate, where the fan is fixed only on one face of the support plate, allowing for lighter blades with reduced thickness and improved aeraulic performance, and a rotational speed measurement system using an encoder wheel and speed sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan is made with high mechanical strength using metal alloys and significant thicknesses to withstand mechanical stresses, then the reliability of the fan is improved, but the mass of the fan increases leading to reduced aeraulic performance and increased noise
Solution Approach 1:
The fan assembly is segmented into two separate components: the fan blades and the support plate. The support plate is fixed to the rotor and provides the necessary mechanical strength to withstand centrifugal forces and pulsating torques, while the fan blades can be made lightweight for optimal aeraulic performance. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
The support plate acts as an intermediary element between the rotor and the fan blades. It transfers mechanical stresses from the rotor to the fan blades while providing a stable mounting structure. The support plate absorbs the mechanical stresses, allowing the fan blades to be made lighter without compromising the overall reliability of the assembly.
2Reliability
If the fan blades are made with significant thicknesses to ensure mechanical strength, then the reliability is improved, but the aeraulic performance is reduced
Solution Approach 1:
By separating the structural support function (handled by the thick support plate) from the aeraulic function (handled by the thin fan blades), the design allows fan blades to have minimal thickness optimized for air flow, while the support plate provides the necessary mechanical strength.
3Reliability
If the fan blades are made with significant thicknesses to ensure mechanical strength, then the reliability is improved, but the noise generated is increased
Solution Approach 1:
The segmentation of the fan assembly allows thin, quiet fan blades to be used while the support plate handles the mechanical stress, reducing noise generation from the blades themselves.
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 reduces the fan's mass without compromising reliability, enhances aeraulic performance, and decreases noise by distributing mechanical stresses, thus improving the overall cooling efficiency and longevity of the fan.
Implementation Method 1
a device for measuring the rotational speed of the fan, the measuring device being composed of an encoder wheel indirectly linked to the fan and a speed sensor fixed to the casing and capable of measuring the speed of rotation of the encoder wheel
Implementation Method 2
the fan being separate from the support plate and fixed only on one of the faces of the support plate... configured to force the circulation of an air flow from the air inlet to each air outlet
Data Source
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AI summary
The invention relates to a cooling device (28) for an electric motor (24) comprising: - a casing (40) defining an air duct (58) connecting an air inlet (52) to at least one air outlet (56), - a fan (42) mounted inside the casing (40) configured to force the circulation of an airflow, and - a device (44) for measuring the rotational speed of the fan (42) comprising an encoder wheel (64) indirectly connected to the fan (42) and a speed sensor (66); The cooling device (28) includes a support plate (46) adapted to be fixed to the rotor (32) of the electric motor (24). The fan (42) is separate from the support plate (46) and fixed only on one of the faces (60A, 60B) of the support plate (46).