Brushless Hammer Drill Stator Assembly for Dust-Proof Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brushless motors for electric tools face challenges in achieving a high space factor, low cost, durability, dust-proof performance, and improved cooling in harsh working environments with vibrations and dust, while also preventing coil disconnection.
Innovation Solution
A brushless motor with a stator core formed by laminating thin electromagnetic steel plates and dividing it into multiple cores, using adhesives and varnishes to enhance integrity, and incorporating a sensor circuit board fixed via fixing pins for improved durability and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stator core is divided into multiple cores, then the space factor increases and cost decreases, but durability and dust-proof performance deteriorate
Solution Approach 1:
The stator core is divided into multiple divided cores arranged circumferentially, each with independent coils. This segmentation increases the space factor by allowing optimized winding arrangements and reduces manufacturing costs through modular production, while maintaining overall motor functionality.
Solution Approach 2:
Multiple divided cores are coupled together to form an integrated stator core structure. The coupling mechanism combines the individual divided cores into a unified assembly that maintains structural integrity and durability comparable to traditional integrated cores, while preserving the benefits of segmentation.
2Productivity
If the stator core is divided into multiple cores, then the space factor increases and cost decreases, but dust-proof performance deteriorates
Solution Approach 1:
An insulating member in the form of a thin film or shell is provided between the divided cores and coils. This insulating layer acts as a barrier that prevents dust penetration into the internal structures while allowing the divided core configuration to maintain its space factor advantages.
3Weight of moving object
If the surface area of the motor decreases for downsizing, then weight reduction is achieved, but cooling performance worsens
Solution Approach 1:
Cooling air passages are configured in the axial direction (another dimension) rather than relying solely on radial surface area. This allows effective cooling despite reduced overall motor size, as the cooling paths extend through the axial dimension where air flow can efficiently remove heat from the divided cores and coils.
4Productivity
If thin electromagnetic steel plates are used, then the space factor increases, but manufacturing cost increases
Solution Approach 1:
The stator core is segmented into multiple divided cores that can be manufactured using standard thickness electromagnetic steel plates. This segmentation allows the use of more readily available, cost-effective materials while achieving the same or better space factor through optimized modular arrangement.
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
The solution achieves a high space factor, low cost, and enhanced durability and dust-proof performance while reducing coil disconnection, with improved cooling through thermal conductivity and reduced chattering sounds.
Implementation Method 1
a varnish or an adhesive is applied over the coils and joining portions between the divided cores
Implementation Method 2
A brushless motor (see Japanese Laid Open Patent Publication No. 2017-35784) that is compact and excels in durability is used as a driving source of an electric tool
Data Source
AI summary
In the brushless motor disposed in a hammer drill, while a stator core of a stator is formed by joining a plurality of divided cores divided in a circumferential direction, varnishes are applied over a coil and joining portions between the divided cores.