Offset Air Exhaust Ports in Power Tool Dual Housing
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Solution Overview
Problem
Existing power tools, such as impact drivers, face challenges in preventing the ingress of foreign matter like dust and water through air exhaust ports, which can cause damage and electrical shorts, especially since the fan is located inside these ports.
Innovation Solution
The design incorporates a dual-housing structure made of polymer material with overlapping portions on the outer circumference of the fan, featuring offset air exhaust ports and communication paths with smaller opening areas than the exhaust ports, ensuring that foreign matter is prevented from entering while allowing effective air exhaust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air exhaust ports are provided in the housing to allow air drawn in by the fan to be exhausted, then cooling of the motor is improved, but foreign matter such as dust and water can enter the housing and cause damage to internal mechanisms and electrical shorts
Solution Approach 1:
The exhaust port is segmented into multiple components: a first exhaust port in the motor housing, a second exhaust port in the rear housing, and communication paths connecting them. This segmentation allows the system to provide multiple exhaust routes while incorporating protective features in the communication paths to prevent foreign matter ingress while maintaining effective air exhaust for motor cooling
Solution Approach 2:
The communication paths act as intermediary structures between the first and second exhaust ports. These communication paths are designed with smaller opening areas than the exhaust ports themselves, serving as protective intermediaries that allow air flow while preventing foreign matter such as dust and water from entering the housing, thus resolving the contradiction between effective exhaust and foreign matter prevention
2Temperature
If the fan is located on the inner side of the air exhaust ports to draw in air for cooling, then cooling efficiency is improved, but the fan becomes vulnerable to damage from foreign matter entering through the exhaust ports
Solution Approach 1:
The communication paths are nested within the housing structure, positioned between the first and second exhaust ports. This nested configuration creates a protective barrier that allows the fan to remain on the inner side of the exhaust ports for effective cooling while the nested communication paths with smaller openings prevent foreign matter from reaching the fan
Solution Approach 2:
The communication paths serve as intermediary protective structures between the external environment and the fan. By designing these communication paths with smaller opening areas than the exhaust ports, the system maintains effective air flow for fan cooling while the intermediary communication paths block foreign matter from reaching and damaging the fan
Data Source
AI summary
A power tool, such as an impact driver, includes a motor having a rotor that rotates relative to a stator, and a centrifugal fan that rotates together with the rotor. A motor housing and a rear housing house the motor. Overlapping parts of the motor housing and the rear housing radially surround an outer circumference of the centrifugal fan. Air exhaust ports are defined in each of the overlapping parts and are offset in an axial direction of the rotor. Fluid communication paths are defined between the air exhaust ports in the overlapping parts. The fluid communication paths have an opening area or width in the axial direction that is smaller than an opening area or width in the axial direction of the air exhaust ports.