Inertial Fan Assembly for Post-Shutdown Power Tool Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power tools with fan assemblies that are fixed to the motor shaft cannot generate cooling airflow during periods of motor deactivation, leading to inadequate cooling of the electric motor.
Innovation Solution
A fan assembly that includes a freely rotatable bearing and a flywheel, allowing it to continue rotating and generating airflow after the motor shaft has stopped, either through stored energy from a spring, compressed air, or an auxiliary fan powered by an energy source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan assembly is fixed to the motor shaft to co-rotate with the motor shaft, then the structure is simple and reliable, but the fan assembly cannot generate cooling airflow during periods of motor deactivation
Solution Approach 1:
The fan assembly is decoupled from the motor shaft through a one-way bearing, allowing it to rotate independently. During motor activation, the fan co-rotates with the motor shaft for simplicity. During motor deactivation, the fan continues rotating independently using stored energy from the flywheel and spring mechanism, maintaining cooling airflow without requiring continuous motor operation.
Solution Approach 2:
The flywheel and spring mechanism store rotational energy and potential energy during motor activation periods. This stored energy is released during motor deactivation to maintain fan rotation and cooling airflow, effectively preparing the system in advance for periods when the motor is not running.
2Duration of action of moving object
If the fan assembly continues to rotate after motor shaft rotation has ceased, then continuous cooling airflow is generated, but additional components such as flywheel and spring are required
Solution Approach 1:
The flywheel and spring mechanism store rotational energy and potential energy during motor activation periods. This stored energy is released during motor deactivation to maintain fan rotation and cooling airflow, effectively preparing the system in advance for periods when the motor is not running.
Solution Approach 2:
The one-way bearing enables the fan assembly to maintain continuous rotation and cooling airflow by decoupling it from the motor shaft. The flywheel and spring mechanism ensure this continuity persists even after motor deactivation, eliminating idle periods where cooling would stop.
3Reliability
If a one-way bearing is used to allow the fan assembly to rotate independently, then the fan can continue rotating after motor deactivation, but the bearing complexity increases
Solution Approach 1:
The fan assembly is decoupled from the motor shaft through a one-way bearing, allowing it to rotate independently. During motor activation, the fan co-rotates with the motor shaft for simplicity. During motor deactivation, the fan continues rotating independently using stored energy from the flywheel and spring mechanism, maintaining cooling airflow without requiring continuous motor operation.
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
Ensures continuous cooling of the electric motor even when the main motor is deactivated, enhancing the tool's operational efficiency and longevity.
Implementation Method 1
The fan assembly includes a freely rotatable bearing and a flywheel, allowing it to continue rotating and generating airflow after the motor shaft has stopped
Implementation Method 2
The power tool further includes a spring coupled to the electric motor and the fan assembly. The spring is configured to receive torque from the electric motor such that the torque winds the spring to store energy when the electric motor is activated and release the energy to supply torque to the fan assembly
Implementation Method 3
the bearing being freely rotatable about the motor axis in the first rotational direction and fixed against rotation about the motor axis in a second rotational direction opposite the first rotational direction
Data Source
AI summary
A method of cooling an electric motor configured for use in a power tool. The electric motor has a motor shaft rotatable about a motor axis. The power tool further includes a fan assembly attachable to the motor shaft and an energy storage device coupled to the motor shaft and to the fan assembly. The method includes activating the electric motor to supply torque to the motor shaft. The method further includes rotating the motor shaft and the fan assembly about the motor axis. The fan assembly generates an airflow to cool the electric motor. Moreover, the method includes supplying torque from the electric motor to the energy storage device and deactivating the electric motor to stall rotation of the motor shaft. The fan assembly continues to rotate about the motor axis to generate the airflow after rotation of the motor shaft has ceased.