PMDC Motor Hall Sensor Relocation for Speed Detection
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Solution Overview
Problem
Conventional PMDC motors face difficulties in installing and maintaining the Hall sensing module due to its interference with the internal magnet field, leading to inaccuracies in revolving speed and direction detection, and increased labor and maintenance costs.
Innovation Solution
The Hall sensing module is positioned on the gear reducer, with a simplified positioning structure and magnetic field interference elimination, allowing for improved installation, maintenance, and operation by placing the magnet ring on the revolving or output shaft, and using a specific arrangement of components like positioning blocks, connectors, and screws for secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Hall sensing module is installed in the motor body, then the revolving speed and direction can be detected, but the installation difficulty increases and the operation is affected by the internal magnet field
Solution Approach 1:
The Hall sensing module is extracted from the motor body and relocated to the external side of the motor. The magnet ring is positioned on the output shaft of the gear reducer, allowing the Hall sensor to detect rotational position without being installed inside the motor body, thereby eliminating installation difficulties while maintaining detection functionality
Solution Approach 2:
The gear reducer serves as an intermediary mechanism between the motor and the load. By placing the magnet ring on the gear reducer's output shaft and the Hall sensor on the external side, the system uses the gear reducer as a mediator to transmit rotational information without requiring direct installation within the motor's magnetic field environment
2Measurement precision
If the Hall sensing module is installed in the motor body, then the revolving speed and direction can be detected, but the operation is affected by the internal magnet field leading to inaccuracies
Solution Approach 1:
The Hall sensing module is extracted from the motor body's internal environment where strong magnetic fields exist. By relocating it to the external side and using the gear reducer's output shaft as the reference point, the sensor operates in a magnetic field environment that does not interfere with its detection accuracy
Solution Approach 2:
The internal magnet field of the motor, which was previously a source of interference when the Hall sensor was installed inside, is no longer problematic because the sensor is positioned externally. The motor's own magnetic field drives the rotor and magnet ring, which in turn generates the magnetic signal that the external Hall sensor detects, converting the potential harm into the detection mechanism itself
3Measurement precision
If the Hall sensing module is installed in the motor body, then the revolving speed and direction can be detected, but the maintenance cost and labor increase
Solution Approach 1:
The Hall sensing module is extracted from the motor body and positioned on the external side, making it accessible for maintenance without requiring disassembly of the motor. The modular design with the magnet ring on the gear reducer allows independent access to both the sensor and the magnetic reference element
Solution Approach 2:
The system is segmented into distinct modules: the motor body, the gear reducer with magnet ring, and the externally mounted Hall sensing module. This segmentation allows each component to be independently accessed, maintained, or replaced without affecting the others, significantly reducing maintenance complexity and labor
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 simplifies the installation and maintenance of the Hall sensing module, enhances its sensing accuracy, and reduces the impact of the motor's magnetic field, thereby improving the detection of revolving speed and direction while lowering costs.
Implementation Method 1
a Hall sensor is disposed on the Hall circuit board to sensor the signal of the magnet ring
Data Source
AI summary
A permanent magnet DC (PMDC) motor, including: a motor body including a revolving shaft; a Hall sensing module; a gear reducer; and a gear assembly including an output shaft; and a magnet ring. The gear assembly is disposed in the gear reducer. The gear assembly is connected to and driven by the revolving shaft of the motor body. The magnet ring is disposed on the revolving shaft or on the output shaft of the gear assembly. The Hall sensing module is disposed on the gear reducer. The Hall sensing module is adapted to sense a signal of the magnet ring to detect the revolving speed of the revolving shaft or the output shaft, and transmit detected data with regard to the revolving speed.