Integrated Rotor Position Sensor for Compact Brushless Motors
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Solution Overview
Problem
Brushless motors in aerospace applications face challenges due to increased length from externally attached position sensors, which compromise packaging space and weight, making them less competitive.
Innovation Solution
Integration of a position sensor within the rotor assembly of the brushless motor, where rotating windings are coupled to the inside of the rotor core and stationary windings are attached to a hollow shaft, reducing motor length and weight by relocating the sensor inside the rotor core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a position sensor is externally attached to the brushless motor housing, then rotor position feedback is provided, but the length of the brushless motor increases
Solution Approach 1:
The position sensor is integrated within the rotor assembly, with the hollow rotor core providing space to accommodate the sensor components. The rotating windings are positioned within the hollow rotor core, and the stationary windings are coupled to the hollow shaft, creating a nested configuration that eliminates the need for external sensor mounting while maintaining functional performance.
2Reliability
If a position sensor is externally attached to the brushless motor housing, then rotor position feedback is provided, but the weight of the brushless motor increases
Solution Approach 1:
The position sensor components are merged with the rotor assembly structure. The hollow rotor core and hollow shaft serve dual purposes: maintaining rotor integrity and providing pathways for sensor windings and leads. This integration eliminates separate external sensor housings and mounting structures, thereby reducing overall weight.
3Reliability
If a position sensor is externally attached to the brushless motor housing, then rotor position feedback is provided, but the packaging space is compromised
Solution Approach 1:
The position sensor components are arranged in the radial dimension within the rotor assembly rather than extending axially outward. The rotating windings are positioned within the hollow rotor core, and the stationary windings are coupled to the hollow shaft, utilizing the radial space already present in the motor structure. This dimensional reorganization maintains compact axial length and optimizes packaging space.
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 solution reduces motor length and weight, preserving performance while optimizing packaging space, making the motor dimensions comparable to those without a position sensor.
Implementation Method 1
a set of rotating position sensor windings positioned within and coupled to an inside diameter of the hollow portion of the rotor assembly and the set of rotating position sensor windings that rotate with the rotor assembly
Implementation Method 2
The hollow shaft may be considered to provide a magnetic flux path for the position sensor windings
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A brushless motor with integrated position sensor is provided. The brushless motor includes a motor housing (202), a stator assembly (206) positioned on an inside outer circumference of the motor housing (202), a rotor assembly (208) positioned within and surrounded by the stator assembly (206), and a position sensor integrated within the rotor assembly (208).