Stepper Motor Stator Teeth Configuration for Smooth Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional stepper motors experience jerky motion and reduced accuracy due to detent torque, with existing solutions often requiring trade-offs between smoothness and microstepping accuracy or holding torque.
Innovation Solution
The stator teeth on stepper motors are rearranged into groups with specific pitch angles to create additional detent positions, reducing detent torque by half and ensuring smoother motion and improved step accuracy without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional stator teeth arrangement is used, then the motor structure is simple, but detent torque causes jerky motion and reduced accuracy
Solution Approach 1:
The stator teeth are divided into multiple groups (first group, second group, third group) with different pitch angles relative to the rotor teeth. This segmentation allows each group to contribute differently to the magnetic field interaction, reducing detent torque and smoothing motion while maintaining manufacturing feasibility through systematic tooth arrangement.
Solution Approach 2:
The patent introduces asymmetric pitch angle relationships between stator teeth groups and rotor teeth. Specifically, the first group has pitch angle θ, the second group has pitch angle 2θ, and the third group has pitch angle 3θ, creating an asymmetric distribution that eliminates the periodic detent torque characteristic of conventional symmetric arrangements.
2Ease of operation
If microstepping mode is used to improve smoothness, then motion smoothness improves, but torque is reduced
Solution Approach 1:
The patent changes the fundamental parameter of stator tooth pitch angles to create multiple groups with θ, 2θ, and 3θ relationships to rotor teeth. This parameter modification reduces detent torque inherently, allowing the motor to maintain higher holding torque while achieving smoother motion without relying solely on microstepping current modulation.
3Manufacturing precision
If detent torque is reduced by half through tooth arrangement, then motion accuracy improves, but the number of detent positions increases
Solution Approach 1:
By dividing stator teeth into three groups with different pitch angles (θ, 2θ, 3θ), the patent creates a segmented structure that generates multiple detent positions. While this increases the number of detent positions, it simultaneously reduces the torque magnitude at each position, resulting in smoother overall motion and improved accuracy through the averaging effect of multiple interaction points.
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 doubles the number of detent positions, reduces detent torque by approximately half, and maintains or improves holding torque, resulting in smoother and more accurate stepper motor operation.
Implementation Method 1
An electrical phase change, applying power to a different set of stator coils, is required to make the motor rotate to a new stable detent position
Implementation Method 2
The rotor includes a permanent magnet and two rotor sections with rotor teeth
Data Source
AI summary
A stepper motor includes a rotor having equally spaced rotor teeth defining a full step angle, and a stator with stator poles wound with coils that can be driven in a series of phases so as to magnetically interact with the rotor to produce stepping motion. The stator poles have teeth organized into two groups when there is an even number of stator teeth per pole, or into three groups for an odd number of stator teeth per pole. The stator teeth have an average pitch different from the rotor's tooth pitch, but the groups of stator teeth are also displaced relative to other groups by a specified offset angle of one-half or one-quarter step to double the number of detent positions, and to displace such detent positions from full one-phase ON or two-phase ON positions.