Integrated Motor Ventilation With Air Deflection for Bidirectional Cooling

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Solution Overview

Problem

Electric motors with inclined blade fans in rail vehicles experience uneven airflow and noise levels due to differential rotation directions, leading to increased load losses and reduced airflow when the rotor turns in the same direction as the fan, necessitating a solution for homogeneous behavior and reduced noise.

Innovation Solution

Incorporating an air deflection organ between the rotor cooling channels and the motorized fan outlet to guide air without centrifugation, ensuring it reaches a central fan zone and avoids impacting the blades, thereby maintaining consistent airflow and noise in both rotation directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the rotor rotates in the same direction as the fan, then the impact area between air and fan blades increases, but this results in increased pressure losses and decreased total flow rate

Engineering Contradiction:

Improveimpact areaVSAvoidpressure losses

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

A stationary air deflection element is introduced as an intermediary component between the rotating rotor and the fan. This deflection element redirects the airflow from the rotor so that it does not directly impact the fan blades, thereby eliminating the harmful pressure losses while maintaining the beneficial cooling airflow

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the rotor rotates in the same direction as the fan, then the change in airflow direction by the blades is greater, but this leads to increased pressure losses

Engineering Contradiction:

Improveairflow direction changeVSAvoidpressure losses

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The stationary air deflection element acts as a mediator that takes over the function of redirecting airflow, preventing the rotating fan blades from having to perform excessive direction changes that would otherwise result in increased pressure losses

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If a fan with angled blades is used to optimize airflow and reduce power consumption, then aerodynamic efficiency improves, but the fan can only operate in one direction of rotation

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidrotation direction

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The airflow control function is segmented between the rotating fan blades and the stationary air deflection element. The fan blades maintain their optimized angled design for unidirectional operation, while the stationary deflection element handles the adaptation to bidirectional rotor rotation, thus preserving aerodynamic efficiency while gaining rotational versatility

Inventive Principle:

Principle #1Segmentation

4Force

If the fan is positioned closer to the rotor to increase centrifugal force, then the impact effect becomes more pronounced, but this increases pressure losses

Engineering Contradiction:

Improvecentrifugal forceVSAvoidpressure losses

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The stationary air deflection element is positioned between the rotor and fan, allowing the fan to be placed closer to the rotor to maximize centrifugal force extraction, while the deflection element prevents the resulting high-velocity air from directly impacting the fan blades and causing pressure losses

Inventive Principle:

Principle #24Intermediary (Mediator)

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 air deflection organ ensures consistent airflow and reduced noise levels by preventing centrifugal effects, minimizing load losses and maintaining optimal airflow rates in both rotation directions, thus meeting thermal dimensioning requirements without requiring excessive flow rates.

Implementation Method 1

a motorized fan for cooling the rotor and the stator, the electric motor comprising at least a first cooling channel for the stator and at least a second cooling channel for the rotor, through which air driven in motion by the fan passes

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

At the outlet of these channels, the air is centrifugal drawn in by the fan. This centrifugal force increases as the rotor's rotational speed increases.

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4498575A1Electric motor with integrated ventilation, in particular for a rail vehicle

Publication Date: 2025.01.29 ALSTOM HOLDINGS SA

Figure 1
Figure 2

AI summary

The electric motor (10) comprises a rotor (20) and a stator (22) housed in a casing (12), and includes a motorized fan (42) for cooling the rotor (20) and the stator (22). The electric motor (10) includes at least one first cooling channel (30) for the stator (22) and at least one second cooling channel (34) for the rotor (20), through which air driven in motion by the fan (42) passes. The electric motor (10) includes at least one air deflection element (54) that guides the air from the second channel (34) to an outlet (40) of the casing (12).