Magnetic Field Sensor Position Detection in Drive Motor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing adjustment systems in motor vehicles, such as window lifter and sliding roof systems, face increased complexity, cost, and weight due to the need for complex position detection methods, particularly for trap-protection functions, which require detecting the position of adjustable elements to prevent trapping hazards.
Innovation Solution
A drive unit with a magnetic field sensor arranged on the pole pot of the drive motor to detect changes in the magnetic field caused by the rotor's rotation, allowing for reliable position detection of adjustable elements without additional signal emitters or complex analysis algorithms, thereby reducing structural complexity and implementation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a position detector with a ring magnet and magnetic field sensor is used to detect the rotary movement of the drive motor, then the position detection reliability is improved, but the device complexity, installation space, cost and weight increase
Solution Approach 1:
The invention extracts and eliminates the ring magnet component from the position detection system. Instead of using a separate ring magnet on the shaft, the drive motor's rotor itself serves as the magnetic field source. The magnetic field sensor detects the rotor's position directly through the motor housing, removing the need for additional signal-emitting components while maintaining detection reliability.
Solution Approach 2:
The drive motor's rotor is made to serve dual functions: both as the actuating component for window movement and as the signal-emitting element for position detection. The rotor's magnetic field, originally used only for motor operation, is now also utilized for position sensing, eliminating the need for separate positioning components.
2Reliability
If current measurement elements are added to analyze current ripple for position detection, then the position detection capability is improved, but the cost increases and drive motor efficiency decreases
Solution Approach 1:
The invention replaces the electrical measurement approach (current ripple analysis) with a magnetic field-based detection system. Instead of measuring electrical parameters that require additional sensors and complex algorithms, the system directly detects the rotor's magnetic field through a magnetic field sensor, simplifying the detection mechanism and avoiding energy losses associated with additional current measurement elements.
3Measurement precision
If additional ring magnets and position detectors are installed on the drive motor shaft, then the position detection accuracy is improved, but the weight and installation space increase
Solution Approach 1:
The invention merges the position detection function with the existing drive motor structure. The magnetic field sensor is integrated into the motor housing or pole shoe, and the rotor serves simultaneously as both the actuator and the position signal source. This integration eliminates separate position detection components, reducing overall weight and installation space while maintaining detection accuracy.
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 reliable position detection of adjustable elements with reduced complexity and cost, eliminating the need for additional components like ring magnets and complex analysis, while maintaining efficiency and effectiveness in preventing trapping hazards.
Implementation Method 1
a magnetic field sensor which is arranged on a pole pot of the drive motor in order to provide an electrical sensor signal dependent on the magnetic field
Implementation Method 2
detect a magnetic field which varies on rotation of a rotor of the drive motor so that a relative position change of the adjustable element can be derived from the electrical sensor signal
Data Source
AI summary
A drive unit for an adjustment system for a motor vehicle has an adjustable element moved by an electric motor. The dive motor is operated electromagnetically. A magnetic field sensor is arranged on a pole pot or a housing of the drive motor to provide an electrical sensor signal dependent on a magnetic field. A control unit is configured to detect the magnetic field. The magnetic field varies on rotation of a rotor of the drive motor, so that a relative position change of the adjustable element can be derived from the electrical sensor signal.