Outer Rotor Brushless Motor Resin Washer Segmentation
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Solution Overview
Problem
Conventional outer rotor-type DC brushless motors face issues with resin washers integrating and rotating, leading to abrasion, reduced bearing durability, increased production costs, and assembly inefficiencies due to complex washer designs and materials.
Innovation Solution
The second resin washer is designed with elastic projected sections that fit into concave sections of the stator core, preventing integrated rotation with the first washer, and features slits and projections for secure positioning, reducing the risk of sludge invasion and enhancing shock resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the second resin washer is made with smaller outer diameter to fit in the center hole, then the washer can be installed without modifying the housing, but the washer cannot effectively prevent integrated rotation with the first resin washer
Solution Approach 1:
The second resin washer is divided into multiple independent engagement projections that can separately engage with corresponding recesses in the first resin washer, preventing integrated rotation while maintaining the washer's overall structural integrity and installation ease
Solution Approach 2:
The engagement projections and recesses are designed with asymmetric geometries that allow proper engagement only in the correct rotational orientation, preventing the washers from rotating together while maintaining ease of installation
2Reliability
If the second resin washer is made non-circular with projected sections to prevent integrated rotation, then bearing durability is improved, but the washer may detach from the center hole when the rotor is lifted
Solution Approach 1:
The engagement projections are pre-formed on the second resin washer to engage with recesses in the first resin washer before the rotor is lifted, preventing detachment while maintaining bearing durability protection
Solution Approach 2:
The engagement projections of the second resin washer are designed to fit into corresponding recesses of the first resin washer, creating a nested engagement structure that prevents both integrated rotation and detachment while maintaining stability
3Reliability
If two or more washers are stacked on the bearing in the thrust direction to prevent integrated rotation, then bearing durability is improved, but the number of parts and production cost increase
Solution Approach 1:
The second resin washer is segmented into multiple independent engagement projections that provide multiple points of restraint against integrated rotation, eliminating the need for multiple separate washers while maintaining bearing durability
Solution Approach 2:
The second resin washer performs multiple functions: it provides thrust support, prevents integrated rotation through engagement projections, and maintains positional stability, eliminating the need for separate components and reducing overall device complexity
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 improves bearing durability, reduces production costs, and simplifies assembly by preventing washer integration and ensuring correct positioning, thus stabilizing rotor rotation and extending bearing lifespan.
Implementation Method 1
the second resin washer is designed with elastic projected sections that fit into concave sections of the stator core
Implementation Method 2
an oil-impregnated sintered bearing 52, which is formed into a cylindrical shape, is coaxially provided in a center hole 51a of a cylindrical housing 51
Implementation Method 3
the first resin washer 62 and the second resin washer 63 will be stuck on each other by surface tension of oil included in the oil-impregnated sintered bearing 52
Implementation Method 4
the first resin washer 62 and the second resin washer 63 will be stuck on each other by surface tension of oil included in the oil-impregnated sintered bearing 52
Data Source
Figure 1A~2B
Figure 3A~4
AI summary
The outer rotor-type blushless motor comprises: a stator (1) including a cylindrical housing (2), a stator core (4) having stator pole teeth (4a) and a bearing (3) coaxially incorporated in a cylindrical hole (2a) of the hosing (2); and a rotor (10) including a rotor yoke (12), a rotor hub (11) provided to the rotor yoke (12) and a rotor shaft (9) rotatably supported by the bearing (3). A first resin washer (14), through which the rotor shaft (9) is pierced and which contacts an end face of the rotor hub (11), and a second resin washer (15), which contacts an end face of the bearing (3) incorporated in a center hole (4e) of the stator core (4), contact each other. The second resin washer (15) has an elastic projected section (15a) fitted in a concave section (4d) formed in the center hole (4e) of the stator core (4).