Handheld Power Tool Cooling via Tubular Rod Air Channel
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Solution Overview
Problem
Existing battery-operated handheld power tools face challenges in effectively cooling high-capacity electric motors and control units, which generate significant heat, leading to inefficiencies and potential damage from dirt and debris contamination.
Innovation Solution
A battery-operated handheld power tool design featuring an elongate tubular rod that creates an air guiding channel between the motor housing and the control unit, allowing a single fan to efficiently cool both components while keeping cooling air clean and preventing heated air from re-entering, with optional insulation to enhance cooling efficiency and the use of PMDC or BLDC motors for robust and cost-effective operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high capacity batteries and powerful motors are used to satisfy demanding consumers, then power and duration of action are improved, but heat generation increases causing temperature to rise
Solution Approach 1:
The patent introduces air as an intermediary cooling medium that flows through the tool housing, battery pack, and motor housing to transfer heat away from heat-generating components. The air flow acts as a thermal mediator between the motor/battery and the external environment, enabling efficient heat dissipation without direct thermal contact.
Solution Approach 2:
The patent employs pneumatic cooling by forcing air through defined flow paths using a fan. The air flow is directed through channels in the tool housing, battery pack, and motor housing to create forced convection cooling, removing heat from the motor and battery components efficiently.
2Temperature
If air is drawn through the guide tube or battery for cooling, then cooling effect is improved, but dirt and debris contamination enters the motor and control unit
Solution Approach 1:
The patent segments the air flow path into distinct zones: a clean air intake zone at the rear of the tool housing, a transport zone through the battery pack and motor housing, and an exhaust zone at the front. This segmentation ensures that air is drawn from a clean area and delivered to heat-generating components without picking up contaminants from the working environment.
Solution Approach 2:
The patent uses air as an intermediary that flows through defined channels to cool components without direct exposure to contaminants. The air acts as a protective medium that can be drawn from clean areas and directed through sealed paths to reach the motor and battery for cooling without picking up dirt and debris.
3Temperature
If air inlets and outlets are positioned close to the working tool, then cooling efficiency is improved, but heated air re-enters through air inlets reducing cooling effectiveness
Solution Approach 1:
The patent inverts the conventional cooling approach by positioning air inlets at the rear of the tool (away from the working tool) and air outlets at the front (near the working tool). This reverse positioning ensures that cool air is drawn from a clean, contaminant-free area and exhausts heated air away from the intake, preventing re-entry and maintaining cooling effectiveness.
Solution Approach 2:
The patent extends the cooling system into the longitudinal dimension of the tool by creating a rear-to-front air flow path. The air intake is positioned at the rear end, flows through the middle sections (battery, motor), and exhausts at the front end, utilizing the length of the tool to create a unidirectional flow that prevents heated air re-entry.
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 achieves enhanced cooling efficiency by maintaining clean air flow and reducing the risk of dirt contamination, while also providing a cost-effective and reliable power tool with improved power economy through the use of PMDC or BLDC motors.
Implementation Method 1
the fan is operable to move cooling air from the exterior of the handle assembly, via the second inner space, the air guiding channel of the tubular rod, to the first inner space and further to the exterior of the working tool assembly
Implementation Method 2
the walls of the elongate tubular rod may have a cooling effect on air which will pass through the air guiding channel
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
A battery operated handheld power tool, comprising a working tool assembly (20), a handle assembly (10) and an elongate tubular rod (30). The working tool assembly (20) comprises a motor housing (26) having a first inner space (27), comprising an electric motor (21 ) with a fan (25). The first inner space (27) is connected to the exterior of the working tool assembly (20) by means of at least one air outlet (28). The handle assembly (10) comprises a second inner space (19) in which a control unit (15) is positioned, the second inner space (19) being in flow communication with the exterior of the handle assembly (10). The elongate tubular rod (30) defines an air guiding channel (33), in flow communication with the first inner space (27) and the second inner space (19).