Blower Motor Cooling via Targeted Brush Airflow
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Solution Overview
Problem
Existing fan devices require a large cooling air flow for efficient engine cooling, which increases space requirements and reduces blower output due to pressure loss, particularly affecting the thermal management of brush contact surfaces in DC motors.
Innovation Solution
A targeted and uniform cooling air flow is directed towards the brush contact surfaces using an angled guide flanks and a drop-shaped cooling air duct design, which divides the cooling air flow to concentrate heat transfer, reducing the overall cooling air flow needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large cooling air flow is diverted from the fan air flow to cool the electric motor, then the cooling efficiency of the motor is improved, but the blower output is reduced due to pressure loss
Solution Approach 1:
The cooling air duct is designed to deliver cooling air directly to the specific locations of heat generation in the motor, namely the brush contact surfaces, commutator, and bearing areas. This localized cooling approach improves cooling efficiency while minimizing the total amount of cooling air required, thereby reducing the impact on blower output.
Solution Approach 2:
The cooling air duct is divided into multiple sections with different orientations (first section parallel to rotor axis, second section perpendicular to rotor axis) to systematically deliver cooling air to different thermal stress points in the motor. This segmented approach ensures comprehensive cooling of all critical components with optimized air flow distribution.
2Temperature
If a large cooling air duct is used to provide sufficient cooling air flow, then the cooling efficiency of the motor is improved, but the space requirements increase
Solution Approach 1:
The cooling air duct is integrated into the motor housing structure, with the duct walls forming part of the housing itself. This nesting approach eliminates the need for separate external cooling ducts, significantly reducing the overall space requirements while maintaining effective cooling air delivery to the motor components.
Solution Approach 2:
The cooling air duct is designed with varying cross-sectional areas along its length, with larger sections near the air inlet and progressively smaller sections as the air approaches the cooling targets. This optimized geometry delivers sufficient cooling air flow to critical areas while minimizing the total volume of the duct structure.
3Temperature
If cooling air is branched off from the fan air flow, then the motor cooling is achieved, but the pressure loss in the blower device increases
Solution Approach 1:
The cooling air duct is positioned to receive cooling air from the fan air flow at an early stage, before the air undergoes significant pressure drops through the blower system. This preliminary branching allows the system to utilize the high-pressure region of the fan air flow for cooling purposes, minimizing the pressure loss impact on overall blower performance.
Solution Approach 2:
The duct design creates minimal flow resistance through smooth transitions and direct pathways from the fan air flow to the cooling locations. By optimizing the local flow characteristics within the duct, the pressure loss associated with branching off cooling air is minimized, preserving blower efficiency.
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
This design enhances heat dissipation from the brush contact surfaces, improving engine cooling efficiency while minimizing space and pressure loss, allowing for smaller and more efficient blower modules.
Implementation Method 1
a cooling air flow for cooling the electric motor being generated by the fan air flow generated by the fan impeller is diverted into a cooling air duct of the motor housing
Implementation Method 2
The contact surfaces of the brushes are in direct contact with the rotor winding and rub against the rotor winding as the rotor rotates... As a result of the friction, the brush contact surfaces become particularly hot
Data Source
Figure 1~2
AI summary
The invention relates to a blower apparatus with an electric motor, which drives a blower wheel, is arranged in a motor housing and has a commutator with at least two brushes, which form in each case an associated brush bearing face with respect to the commutator, wherein a cooling air flow for cooling the electric motor is diverted into a cooling air channel of the motor housing by a blower air flow produced by the blower wheel. The invention is based on the object of designing the motor cooling system of the blower apparatus of the generic type in such a way that it is more efficient. The object is achieved by virtue of the fact that the cooling air channel (10) has an air distributor (20) which splits the cooling air flow into at least two cooling air subflows, which are in each case supplied to one of the brush bearing faces (9a) directly and in targeted fashion.