External Rotor Fan Cooling Channel for Quiet Motor Electronics Cooling
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Solution Overview
Problem
Existing fans with outer runner engines face challenges in cooling both motor electronics and drive components, especially at low speeds, and often generate noise at high speeds due to activated cooling wheels.
Innovation Solution
A fan design with an external runner motor that utilizes a continuous cooling channel to passively generate a cooling air flow through a pressure difference created by the ventilator wheel, effectively cooling both the motor electronics and drive components without the noise associated with active cooling wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an active cooling impeller is installed on the rotor to cool motor electronics, then cooling capacity is improved, but noise increases at high speeds and additional torque is required reducing efficiency
Solution Approach 1:
The cooling function is extracted from the rotating active cooling impeller and integrated into the stationary housing structure. The housing now contains cooling channels that passively guide cooling air along the motor electronics and drive components, eliminating the need for the active cooling impeller and its associated noise and torque requirements.
Solution Approach 2:
The fan's own operation creates the pressure difference that drives the cooling air flow through the housing channels. The fan wheel generates a pressure difference between its suction side and pressure side, and this pressure difference automatically drives cooling air through the channels along the electronics and motor components without requiring any additional active cooling mechanism.
2Temperature
If an active cooling impeller is used to cool motor components, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The cooling function is merged with the housing structure itself. The housing now contains integrated cooling channels that guide cooling air along the motor electronics and drive components. This eliminates the need for separate active cooling impellers and control systems, reducing device complexity while maintaining cooling effectiveness.
Solution Approach 2:
The housing serves multiple functions: it protects the internal components, structures the motor assembly, and now also provides the cooling channel network. This multi-functional design eliminates the need for dedicated active cooling components, simplifying the overall system.
3Temperature
If wall thickness of electronics housing is increased to absorb more heat, then cooling capacity is improved, but weight increases
Solution Approach 1:
Instead of relying on thermal conduction through thick housing walls, the invention uses pneumatic cooling by channeling cooling air through the housing structure. The cooling channels guide airflow directly along the heat-generating components, efficiently removing heat through convective heat transfer without requiring increased material mass.
4Temperature
If materials with higher thermal conductivity are used to improve heat dissipation, then cooling capacity is improved, but manufacturing cost increases
Solution Approach 1:
The invention replaces thermal conduction-based cooling with pneumatic cooling through integrated airflow channels. This allows the use of standard, cost-effective housing materials while achieving superior cooling performance through controlled air flow along the motor electronics and drive components.
5Object-generated harmful factors
If a passive cooling system is used to reduce noise, then noise level is reduced, but cooling capacity at low speeds may be insufficient
Solution Approach 1:
The cooling channels are strategically positioned and oriented to maximize exposure to the fan's airflow field. The channels run along the motor electronics and drive components in locations where they receive adequate cooling air even at low fan speeds, ensuring sufficient heat dissipation without requiring active cooling mechanisms that generate noise.
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 provides improved cooling efficiency even at low speeds, reduces noise, and maintains a compact structure, allowing for increased power or the use of smaller motors, which saves costs.
Implementation Method 1
the fan generates a pressure difference via the fan wheel between its suction side, preferably assigned to the rotor, and its pressure side, preferably assigned to the motor electronics
Implementation Method 2
a cooling air flow through the cooling channel can be generated exclusively passively by the pressure difference generated by the fan wheel in order to cool both the electronics section and the motor section
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to a fan with an external rotor motor comprising a motor section and an electronics section, wherein the motor section and the electronics section are arranged axially adjacent to each other along the axis of rotation, wherein the fan, in its intended operation, generates a pressure difference between its suction side, preferably associated with the rotor, and its pressure side, preferably associated with the motor electronics, via the fan wheel, wherein a continuous cooling channel runs within the external rotor motor from a pressure-side inlet opening and at least sectionally along the rotor to a suction-side outlet opening, and in operation a cooling airflow through the cooling channel can be generated exclusively passively by the pressure difference generated by the fan wheel.