Actuator With Segmented Stator Poles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional step motors face challenges in maintaining a uniform gap between the permanent magnet rotor and stator, leading to increased loss due to magnetic flux leakage, degraded conversion efficiency, and variations in driving speed.
Innovation Solution
The actuator design includes a coil, a permanent magnet rotor, a bobbin, and two stators with alternately arranged inner and outer magnetic pole portions that extend inside and outside the coil, allowing for a closed magnetic path and reduced air gap, thereby minimizing magnetic flux leakage and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional step motor structure with permanent magnet rotor and stator is used, then the basic motor function is achieved, but the gap between rotor and stator cannot be kept uniform leading to magnetic flux leakage
Solution Approach 1:
The stator is divided into multiple magnetic pole portions (inner and outer magnetic poles) that are arranged alternately in the circumferential direction. This segmentation allows the magnetic flux paths to be distributed and contained within defined regions, reducing leakage loss while accommodating manufacturing variations in gap uniformity.
Solution Approach 2:
A non-magnetic bobbin is introduced as an intermediary component between the coil and the magnetic pole portions. The bobbin provides a stable mounting structure for the coil and maintains consistent positioning relative to the rotor, thereby ensuring uniform air gap without requiring high manufacturing precision in the stator components themselves.
2Productivity
If the gap between rotor and stator is not uniform, then manufacturing is easier, but conversion efficiency is degraded
Solution Approach 1:
The stator incorporates both inner magnetic pole portions extending inside the coil and outer magnetic pole portions extending outside the coil, arranged alternately. This local differentiation creates multiple localized magnetic paths that are less sensitive to overall gap variations, maintaining conversion efficiency even when perfect uniformity is difficult to achieve in manufacturing.
3Loss of energy
If conventional stator arrangement is used, then structure is simple, but magnetic flux leakage increases loss
Solution Approach 1:
The inner and outer magnetic pole portions are integrated into a single stator structure that is secured to the bobbin. This merging of multiple magnetic pole functions into one unified stator assembly reduces the number of separate parts and assembly steps, controlling device complexity while achieving reduced magnetic flux leakage through the alternating pole arrangement.
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 reduces magnetic flux leakage, improves drive output, and achieves high drive efficiency and operational stability by effectively transmitting magnetic flux and reducing the number of parts that define the positional relationship between the rotor and stators.
Implementation Method 1
a coil; a permanent magnet rotor secured to and rotatably supported by an output shaft inside the coil
Implementation Method 2
the inner magnetic pole portion and the outer magnetic pole portion of the first stator are arranged alternately in a circumferential direction, and the inner magnetic pole portion and the outer magnetic pole portion of the second stator are arranged alternately in the circumferential direction
Data Source
AI summary
An actuator includes: a coil; a permanent magnet rotor secured to and rotatably supported by an output shaft inside the coil; a bobbin made of a non-magnetic material and around which the coil is wound; a first stator inserted into and secured to the bobbin in one direction, and including an inner magnetic pole portion and an outer magnetic pole portion extending inside and outside the coil in an axial direction of the rotor, respectively; and a second stator inserted into and secured to the bobbin in a direction opposite to the one direction, and including an inner magnetic pole portion and an outer magnetic pole portion extending inside and outside the coil in the axial direction of the rotor, respectively.