Brushless Motor Fan Guide With Labyrinth Dust Blocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electric tools, particularly disc grinders with brushless DC motors, face inadequate cooling performance for the inner stator coils due to insufficient air volume and dust accumulation, which can lead to overheating and reduced efficiency.
Innovation Solution
The design incorporates a fan guide that concentrates cooling air within the stator, utilizing a labyrinth structure formed by modifying the insulator and fan guide shapes to enhance airflow and prevent dust adhesion, along with a filter attachment mechanism that allows easy removal and secure attachment to prevent dust intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the air volume of the cooling air is increased to prevent dust adhesion on the rotor, then the cooling performance improves, but the size of the cooling fan that can be used may be limited by the size of the motor housing
Solution Approach 1:
The invention segments the cooling function into two fans with different roles: the first cooling fan handles outer peripheral cooling and can be larger, while the second cooling fan handles inner stator cooling and dust prevention and can be smaller. This segmentation allows the system to achieve high air volume for dust prevention without requiring a single oversized fan that would exceed housing constraints.
Solution Approach 2:
The invention introduces a filter between the cooling air source and the motor housing that captures dust particles before they can adhere to the rotor. This intermediary component allows the system to maintain effective cooling air flow while preventing dust accumulation, resolving the contradiction between needing high air volume and preventing dust adhesion.
2Object-affected harmful factors
If a filter is provided at the intake port to suppress intrusion of dust, then dust adhesion is prevented, but a large amount of dust may adhere to the filter in a short time requiring frequent maintenance
Solution Approach 1:
The invention introduces a removable filter as an intermediary component at the cooling air intake port that captures dust particles. The filter is designed to be easily detachable, allowing users to remove and clean or replace it when dust accumulates. This resolves the contradiction by providing effective dust protection while making maintenance simple and convenient.
3Temperature
If the rotational speed of the cooling fan is increased to improve cooling performance, then cooling efficiency improves, but the cooling fan is attached to the rotation shaft of the motor and rotates in synchronization with the motor, so the rotational speed cannot be independently increased
Solution Approach 1:
The invention segments the cooling function into two independently controllable cooling fans: a first cooling fan and a second cooling fan. This segmentation allows the second cooling fan, which is responsible for inner stator cooling and dust prevention, to operate at higher rotational speeds independent of the motor's rotation speed, thereby improving overall cooling efficiency without being constrained by motor synchronization.
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 configuration ensures effective cooling of the motor's inner components, preventing dust adhesion and maintaining tool performance, while maintaining the tool's size and cost efficiency.
Implementation Method 1
a cooling fan that can be attached to a rotation shaft of the motor is provided, and a heat generating portion is cooled by sucking outside air and sending cooling air to the motor. The cooling air is configured to flow in an axial direction on an outer peripheral side of a stator and in a space between a rotor and the stator.
Implementation Method 2
The fan guide is provided, guides cooling air generated by the cooling fan from an intake port to an exhaust port, and guides the cooling air to concentrate inside the stator.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electric tool is provided which enables preventing adherence to a rotor core of dust, such as iron powder, that has entered a motor. The electric tool includes a cylindrical motor housing 10 accommodating and supporting the motor, and a cooling fan attached to a rotation shaft of the motor, and cools the motor by flowing air generated by the cooling fan toward the back or front of the motor housing 10, wherein a fan guide 50 guiding cooling air is provided in front of an insulator 35 of a stator 30 of the motor. The fan guide 50 includes a first cylindrical part 51 which covers a rotation space of the cooling fan, a guide surface 53, and a second cylinder 55 which extends backward from the guide surface 53, wherein a labyrinth space 39 is formed by the insulator 35 and the second cylinder 55. By providing the labyrinth space 39, it is possible to block the flow of cooling air from the outer peripheral side of the stator 30 to an opening 53a.