Brushless Motor Bearing Holder Alignment for Precise Rotor-Stator Gap
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Solution Overview
Problem
Existing brushless motors in electric tools face inaccuracies in the rotor-stator gap due to backlash during assembly, which affects the precision and performance of the motor unit.
Innovation Solution
A brushless motor configuration that includes a rotor, stator, and bearings, where the bearing holder is positioned by a contact surface alignment between the stator core and the bearing holder, improving the accuracy of the rotor-stator gap by reducing misalignment and backlash, and both bearings are held by the stator core for enhanced assembly precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the motor unit, bearings, and housing are assembled using conventional rib members, then the assembly process is simple and easy to manufacture, but backlash and misalignment occur leading to reduced rotor-stator gap accuracy
Solution Approach 1:
The bearing holder is integrated directly into the stator core, merging two previously separate components (stator core and bearing holder) into a unified structure. This integration eliminates the need for separate rib members and reduces assembly steps while improving rotor-stator gap accuracy by preventing backlash and misalignment between the motor unit and housing.
2Manufacturing precision
If separate motor holders and bearing holders are used to support the motor unit, then the structure provides adequate support, but alignment errors accumulate during assembly reducing precision
Solution Approach 1:
The bearing holder is formed as an integral part of the stator core, eliminating the need for separate motor holders and bearing holders. This merger reduces the number of components and assembly steps, making manufacturing easier while simultaneously improving alignment precision by eliminating cumulative alignment errors from multiple separate parts.
Solution Approach 2:
The stator core itself provides the bearing holder function, allowing the stator core to support its own bearings directly. This self-service approach eliminates the need for external support structures and reduces assembly complexity while maintaining high alignment precision.
Data Source
AI summary
The rotor includes a rotary shaft, a rotor core, and a plurality of permanent magnets. The stator includes a stator core and a plurality of coils. The stator core has a first contact surface. A normal vector to the first contact surface is aligned with a radially inward direction defined for the rotary shaft. A bearing holder (first bearing holder) has a second contact surface in contact with the first contact surface. A normal vector to the second contact surface is aligned with a radially outward direction defined for the rotary shaft. The bearing holder is positioned by bringing the first contact surface into contact with the second contact surface.