Brushless Motor Rotor with Plastic Covers and Integrated Anchors
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Solution Overview
Problem
Traditional micro brushless motors require expensive materials like stainless steel and copper, leading to high production costs and performance degradation due to strict tolerance requirements.
Innovation Solution
A micro brushless motor design featuring a rotor core with plastic covers and rare earth magnets, where axially extending grooves and anchors engage with the covers for secure mounting, and fins for air flow to reduce costs and simplify structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stainless steel keeper ring is used to retain magnets, then magnets are securely retained against centrifugal force, but production cost increases and manufacturing complexity increases due to strict tolerance requirements
Solution Approach 1:
The patent replaces expensive stainless steel keeper rings with inexpensive plastic covers that perform the same function of retaining magnets. The plastic covers are molded with integrated anchors that engage with grooves in the rotor core, providing secure magnet retention without the need for precision-machined metal components. This substitution dramatically reduces production cost while maintaining reliability.
Solution Approach 2:
The patent uses composite construction by combining plastic covers with metal anchors embedded in the rotor core. The plastic covers provide cost-effective retention while the metal anchors provide structural strength. This composite approach eliminates the need for entirely metal keeper rings while maintaining the required mechanical strength for magnet retention.
2Stability of the object's composition
If copper metal discs are used for rotor balancing, then rotor balance is achieved, but production cost increases
Solution Approach 1:
The patent replaces expensive copper metal discs with inexpensive plastic balance members that are molded into the rotor structure. These plastic balance members perform the same function of counterbalancing the rotor while costing significantly less than copper. The balance members are integrated into the plastic cover assembly, eliminating the need for separate metal disc components.
3Power
If thin stainless steel keeper ring is used (less than 0.2 mm), then motor performance is maintained, but tooling is needed and tolerance control must be strict
Solution Approach 1:
The patent eliminates the need for precision-machined thin stainless steel keeper rings by using molded plastic covers with integrated retention features. The plastic covers are manufactured using molding processes that inherently provide consistent dimensions without requiring post-machining or strict tolerance control. The anchors are formed as integral parts of the molded covers, engaging with grooves in the rotor core to secure magnets.
Solution Approach 2:
The patent replaces the mechanical machining process required for stainless steel keeper rings with a molding process for plastic covers. The molding process creates the retention features directly during formation, eliminating the need for subsequent machining operations and strict tolerance control. The plastic material allows for easier manufacturing with standard tolerances.
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 design reduces production costs by eliminating the need for stainless steel and copper, while maintaining reliability through improved sealing and balancing, and enhancing cooling efficiency.
Implementation Method 1
a plurality of fins are formed in at least one of the covers to generate air flow when the rotor is rotating and the air flow flows along an air passage
Implementation Method 2
the interface between the two covers is sealed by adhesive
Data Source
AI summary
A brushless motor comprises a stator and a rotor rotatably mounted to the stator. The rotor comprises a shaft, a rotor core fixed onto the shaft and magnets fixed to the rotor core. Two covers are fitted to respective ends of the rotor core, with one of the covers covering one end of the rotor core and at least a part of the radially outer peripheral surface of the rotor core, while the other cover at least covering the other end of the rotor core. Preferably, the entire peripheral surface of the rotor core is substantially covered by the two covers and the gap between the two covers is sealed by adhesive.