Stepper Motor Rotary Position Sensor Integration
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Solution Overview
Problem
Existing electric motors, particularly stepper motors, face challenges in accurately determining the rotational position of their rotor with high resolution and precision due to the space, cost, and complexity issues associated with traditional optical or magnetic encoders and monolithic magnetic sensor ICs.
Innovation Solution
A device is integrated into the electric motor with reference bores on the motor housing and carrier pins to precisely position a magnetic sensor IC relative to a rotary encoder magnet, allowing for wireless detection of the rotor's position with high accuracy and reduced manufacturing effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical or magnetic encoders with separate bearings are used to determine rotor position, then measurement precision is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the encoder magnet, sensor IC, and positioning reference elements into an integrated motor assembly. The magnet is mounted directly on the rotor, the sensor IC is mounted on the stator, and reference bores are provided in the motor housing to define precise angular relationships, eliminating the need for separate encoder bearings and complex positioning mechanisms.
2Manufacturing precision
If monolithic magnetic sensor ICs with Hall effect are used, then manufacturing precision is improved, but calibration complexity increases due to insufficient position reference on motor housing
Solution Approach 1:
The patent incorporates reference bores directly into the motor housing during manufacturing. These bores provide pre-defined angular references that allow the sensor IC to be positioned and calibrated relative to the rotor magnet without complex post-assembly adjustments. The reference bores establish precise geometric relationships between the sensor and magnet positions.
3Measurement precision
If high-resolution position detection is implemented, then measurement precision is improved, but cost increases due to complex encoder systems
Solution Approach 1:
The patent replaces complex mechanical encoder systems with a simplified magnetic field-based detection system. A magnet mounted on the rotor generates a magnetic field that is detected by a Hall effect sensor IC on the stator, eliminating the need for mechanical encoders, optical components, and associated mechanical positioning mechanisms while achieving high-resolution position detection.
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 solution enables precise and cost-effective wireless detection of the rotor's position with minimal mechanical adjustment, enhancing the accuracy and efficiency of motor control in mechatronic applications.
Implementation Method 1
the recently developed high-resolution, monolithic, magnetic sensor ICs, whose operation is based on the Hall effect
Data Source
Figure 1
AI summary
An electric motor, in particular a stepper motor, is described, which has a device for determining the position or rotational orientation of its rotor or motor shaft by means of a rotary encoder (12) arranged on the motor and actuated by the rotation of the rotor or motor shaft, and a sensor (41) which is oriented for wireless detection of rotation signals generated by the rotary encoder (12) in relation to the rotary encoder (12). The sensor (41) is mounted on a carrier plate (40) which is attached to the motor by means of carrier pins (331, 332) that are fixed to reference bores (131, 132; 431, 432) in the motor and the carrier plate.