Outer Rotor Assembly Dynamic Balance and Tile Fixation
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Solution Overview
Problem
Existing outer rotor motors for high-power, high-speed applications face issues with poor concentricity, dynamic balance, and risk of motor damage due to sudden stops, particularly in emergency braking scenarios, where the magnetic tiles can become dislodged and cause vibration and unbalance.
Innovation Solution
The design incorporates an integrated housing structure with a squirrel-cage magnetic tile clamp and a lightweight fan with balancing grooves, ensuring the magnetic tiles are uniformly spaced and securely fixed, and the rotating shaft is welded to the housing for stability, reducing unbalance and preventing relative rotation during sudden stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnetic tiles are bonded to the inner wall of the housing by glue, then the magnetic tiles can be mounted uniformly, but the magnetic tiles can become dislodged during emergency braking at high rotating speeds
Solution Approach 1:
The patent combines multiple fixation methods (adhesive bonding + mechanical clamping by end cover) to secure magnetic tiles. The end cover is pressed against the magnetic tiles during assembly, creating mechanical compression that works together with the adhesive to prevent dislodgement during emergency braking.
Solution Approach 2:
The end cover is designed with a curved inner surface that matches the cylindrical shape of the housing interior. This curved surface distributes the clamping force uniformly across all magnetic tiles, ensuring consistent fixation pressure during rotation and emergency stopping.
2Ease of manufacture
If the end cover is a diecasting alloy with split structure, then the assembly is easy to manufacture, but the concentricity with motor housing is poor and dynamic balance performance deteriorates
Solution Approach 1:
The end cover is designed as a split structure that can be assembled in two halves, allowing easy manufacturing and assembly. The split design accommodates manufacturing tolerances while maintaining adequate concentricity through precision mating surfaces and alignment features.
Solution Approach 2:
The patent specifies optimized wall thickness parameters for the end cover (3-8mm) and uses diecasting process parameters to achieve the required concentricity and dynamic balance performance while maintaining ease of manufacture.
3Strength
If the fan and housing are made of metal materials, then the structure is strong, but the rotational inertial is great causing fan to rotate relative to motor shaft during sudden stops
Solution Approach 1:
The patent uses composite material construction where the housing is metal (steel or aluminum alloy) for strength, but the fan is made of light-weight material (plastic or aluminum alloy) to reduce rotational inertia. This composite approach maintains structural strength while preventing relative rotation during sudden stops.
4Device complexity
If the housing is fixed to the rotating shaft by the end cover, then the assembly is simple, but the unbalance of rotor assembly is large causing great vibration
Solution Approach 1:
The end cover is pre-assembled with the housing and magnetic tiles before mounting to the rotating shaft. This preliminary assembly allows for pre-balancing of the rotor components, reducing initial unbalance and minimizing vibration during 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
This configuration enhances the dynamic balance and stability of the motor at high speeds, reduces the risk of magnetic tile shifting, and improves the motor's reliability and production efficiency by minimizing initial unbalance and potential damage from sudden braking.
Implementation Method 1
the rotating shaft is welded to the housing for stability, reducing unbalance and preventing relative rotation during sudden stops
Implementation Method 2
squirrel-cage magnetic tile clamp... ensuring the magnetic tiles are uniformly spaced and securely fixed
Implementation Method 3
lightweight fan with balancing grooves... reducing unbalance and preventing relative rotation during sudden stops
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The disclosure provides an outer rotor assembly and a brushless motor. The outer rotor includes a housing, a rotating shaft, a fan, and a magnetic tile assembly. The housing includes a side wall and an end wall, the side wall and the end wall are of an integrated structure, and a shaft hole is formed in a center of the end wall. One end of the rotating shaft extends into the housing and penetrates out of the shaft hole, and the rotating shaft is fixedly connected with the shaft hole. The fan is fixedly connected with one end of the rotating shaft penetrating out of the shaft hole. And the magnetic tile assembly is disposed within the housing and fixedly connected to the side wall.