Stepping Motor Stator Notch Layout for Precise 60° Timepiece Steps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing stepping motors face challenges in achieving stable and accurate 60° step angles for precise hand movement in timepieces due to unstable magnetic flux distribution and torque distribution, particularly in triple coil configurations.
Innovation Solution
The stepping motor design incorporates a stator with overhanging sections featuring first and second notches that regulate magnetic flux direction, along with a rotor receptacle and yokes, allowing the magnetic flux to flow in a detoured path around the second notch, stabilizing the rotor's stop at desired positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stator design with one magnetic flux saturation section and two recesses is used, then the motor can operate in predetermined steps, but the magnetic flux distribution becomes unstable and torque distribution is inconsistent
Solution Approach 1:
The stator is divided into multiple sections with different notch configurations. The first notches are provided on both sides across the rotor, and second notches extend further toward the end side, creating segmented magnetic flux paths that stabilize flux distribution and improve torque consistency across different operational positions.
Solution Approach 2:
Different regions of the stator are given different properties through the notch design. The first notches create magnetic flux saturation at specific locations, while the second notches extend further to control flux distribution in other regions, allowing each part of the stator to optimize its function for stable magnetic flux and consistent torque.
2Volume of stationary object
If the stator size is reduced to minimize motor size, then the motor fits better in timepieces, but the magnetic flux distribution becomes unstable
Solution Approach 1:
The notch design extends in the longitudinal direction of the stator, utilizing the length dimension to control magnetic flux distribution. By having second notches extend further toward the end side than first notches, the design compensates for reduced cross-sectional area, maintaining stable flux distribution in a compact volume.
3Manufacturing precision
If triple coil configuration is used to achieve 60° step angles, then the step precision can be improved, but the torque distribution becomes unstable
Solution Approach 1:
The stator features asymmetric notch arrangements where second notches extend further toward the end side than first notches. This asymmetric design compensates for torque distribution instability in triple coil configurations, ensuring consistent torque across all three coil phases while maintaining 60° step precision.
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 the rotor to stop accurately at predetermined 60° steps with high precision, ensuring stable hand movement in timepieces while minimizing the motor's size and enhancing electrical performance.
Implementation Method 1
a plurality of coils magnetically coupled to the stator
Implementation Method 2
two yokes located along a longitudinal direction of the straight section on both sides of the straight section respectively
Implementation Method 3
the overhanging section has first notches provided at least on both sides across the rotor and second notches extending further toward an end side in the first direction of the stator than the first notches
Data Source
AI summary
Disclosed is a stepping motor including: a rotor magnetized in a radial direction; a stator having a straight section extending in a first direction, an overhanging section provided on at least one end side of the straight section and overhanging in a direction intersecting an extending direction of the straight section, and a rotor receptacle provided in the overhanging section to receive the rotor; two yokes located along a longitudinal direction of the straight section on both sides of the straight section respectively; and a plurality of coils magnetically coupled to the stator. The overhanging section has first notches provided at least on both sides across the rotor and second notches extending further toward an end side in the first direction of the stator than the first notches.