Rotor Core Bearing Layout for Compact Motor Axial Size
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Solution Overview
Problem
Current motor designs face limitations in miniaturization due to the need for minimum height in the shaft direction for bearings, which restricts the reduction of motor size without degrading performance.
Innovation Solution
The motor incorporates bearings disposed in grooves within the rotor core, allowing for a reduced motor size in the shaft direction by optimizing the arrangement of magnets and bearings, with specific protrusions guiding magnet placement and serving as stoppers for bearings to maintain preset positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If bearings are disposed on upper and lower portions of the shaft, then the motor structure is simple and bearings are easily installed, but the motor size in shaft direction cannot be reduced
Solution Approach 1:
The bearing is nested inside the rotor core by forming a groove within the rotor core structure. This allows the bearing to be housed within the existing motor components rather than requiring separate mounting space on the shaft, thereby reducing the overall motor size in the shaft direction while maintaining bearing functionality
Solution Approach 2:
The bearing arrangement transitions from a one-dimensional shaft-mounted configuration to a three-dimensional integrated structure within the rotor core. By utilizing the radial and axial dimensions of the rotor core, the bearing is repositioned from external shaft mounting to internal rotor core housing, enabling compact motor design
2Volume of moving object
If magnets are arranged with minimum height in shaft direction, then motor size is reduced, but bearing arrangement becomes limited
Solution Approach 1:
The rotor core is segmented into functional regions: a first region for magnet arrangement and a second region for bearing housing. This segmentation allows independent optimization of each region - magnets can be arranged with minimal height while the second region provides dedicated space for bearing installation, resolving the conflict between size reduction and bearing arrangement flexibility
Solution Approach 2:
Different regions of the rotor core are assigned different functional qualities - the first region is optimized for magnetic field generation with compact magnet arrangement, while the second region is structured to accommodate bearings. This local differentiation enables both size reduction and proper bearing support
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 enables a smaller motor size while preventing magnetic flux leakage and ensuring precise magnet arrangement, allowing for efficient operation and reduced risk of bearing misalignment.
Implementation Method 1
an electrical interaction is induced between the stator and the rotor so that the rotor rotates
Implementation Method 2
a bearing coupled to the shaft is disposed in the groove
Data Source
AI summary
An embodiment relates to a motor comprising: a shaft; a rotor coupled to the shaft; and a stator disposed on the outside of the rotor, wherein the rotor includes a rotor core and a plurality of magnets disposed on the outer circumferential surface of the rotor core, wherein the rotor core includes a first region coupled to the shaft and a second region disposed on the outside of the first region, and wherein the upper or lower portion of the second region radially overlaps a bearing coupled to the shaft. Accordingly, the size of the motor can be reduced compared to the conventional art.