Hall Effect Sensor Assembly for Vehicle Door Motor Direction Detection
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Solution Overview
Problem
Existing power sliding door (PSD) and power lift gate (PLG) systems face challenges in determining motor rotational direction and speed due to limitations in sensor technology, particularly with detecting closely spaced gear teeth associated with the rotor.
Innovation Solution
The implementation of a drive assembly utilizing a pair of Hall effect sensor modules with a bias magnet to detect ferrous teeth on a rotating wheel, generating signals indicative of rotational direction and speed, which are then used to control the motor and door movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional sensor is used to detect motor movement, then the system structure is simple, but the sensor cannot output signals indicative of motor rotational direction and speed by detecting closely spaced gear teeth
Solution Approach 1:
The sensor system is divided into two separate Hall effect sensor modules, each with two sensor elements. The first module detects tooth peaks while the second module detects tooth valleys, allowing independent optimization of each module's function. This segmentation enables precise detection of closely spaced gear teeth by distributing the detection task across multiple specialized sensor elements rather than using a single complex sensor.
Solution Approach 2:
A bias magnet is introduced as an intermediary component to enhance the magnetic field interaction between the rotor teeth and Hall effect sensor elements. The bias magnet creates a predetermined magnetic field that amplifies the magnetic flux changes caused by passing teeth, enabling more reliable detection signals without requiring direct mechanical contact or complex optical systems.
2Measurement precision
If Hall effect sensor modules are used to detect closely spaced gear teeth, then rotational direction and speed can be accurately detected, but the device complexity increases due to multiple sensor elements and modules
Solution Approach 1:
The two Hall effect sensor modules are positioned asymmetrically relative to the rotor teeth. The first module's sensor elements are oriented to detect tooth peaks while the second module's elements detect tooth valleys. This asymmetric positioning and functional differentiation allows the system to distinguish rotational direction by comparing the sequence of peak and valley detections, providing accurate direction and speed measurement from closely spaced teeth.
Solution Approach 2:
The detection system utilizes multiple spatial dimensions by positioning sensor elements at different locations and orientations around the rotor perimeter. Rather than using a single linear array of sensors, the Hall effect modules are distributed in a two-dimensional arrangement that captures magnetic field variations from multiple angles, enabling precise detection of closely spaced teeth through spatial differentiation.
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 provides accurate and reliable detection of motor rotational direction and speed, enabling effective control of vehicle doors and lift gates, overcoming space limitations and interface restrictions with the electronic control unit (ECU).
Implementation Method 1
A first Hall effect sensor module mounted to the housing in a facing spaced relationship with respect to the plurality of teeth of the rotor. The first Hall effect sensor module has first and second Hall effect sensor elements.
Data Source
AI summary
A drive assembly for a vehicle door is provided. The drive assembly includes a motor having a driving member. The drive assembly further includes a housing having a shaft rotatably received therein. The drive assembly further includes an input member being rotatably received upon the shaft. The input member is operatively associated with the driving member. The drive assembly further includes a rotor fixedly secured to the shaft. The drive assembly further includes first and second Hall effect sensor modules mounted to the housing in a facing spaced relationship with respect to the plurality of teeth of the rotor that generate first and second signals, respectively. The first and second signals have a quadrature relationship with respect to one another and indicate a rotational direction of the rotor when the plurality of teeth are rotating past the first and second Hall effect sensor modules.