Hall Effect Linear Position Sensor Diametrical Magnet Alignment
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Solution Overview
Problem
Existing Hall effect linear position sensors for motor vehicle clutch master cylinders rely on rare earth magnets, which are costly and sensitive to noise, limiting their efficiency and cost-effectiveness.
Innovation Solution
A Hall effect linear position sensor utilizing a diametrically magnetized magnet with specific angular positioning within a housing, optimizing magnetic field alignment and reducing noise sensitivity, and potentially using anisotropic ferrite or rare earth materials, with grooves and ribs for precise alignment and cost reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare earth magnets are used in the Hall effect sensor, then magnetic performance and remanence are improved, but production cost increases significantly
Solution Approach 1:
The patent changes the magnetization parameter from axial to diametrical magnetization. This parameter change allows the use of less expensive ferrite materials while maintaining adequate magnetic field strength for the Hall effect sensor, thereby reducing production cost while preserving sufficient magnetic performance
Solution Approach 2:
The patent employs a composite structure combining ferrite material with precise diametrical magnetization orientation. This composite approach leverages the cost优势 of ferrite while using magnetic field orientation to achieve performance previously only attainable with expensive rare earth magnets
2Device complexity
If axial magnetization is used in the magnet, then the magnetic field detection is simplified, but noise sensitivity increases and reading range is limited
Solution Approach 1:
The patent changes the magnetization direction parameter from axial to diametrical. This parameter change optimizes the magnetic field distribution to be more parallel to the piston movement direction, improving signal-to-noise ratio and extending the effective reading range while maintaining detection circuit simplicity
Solution Approach 2:
The patent transitions from one-dimensional axial magnetization to two-dimensional diametrical magnetization. This dimensional change in the magnetic field configuration creates a more favorable field geometry that reduces noise sensitivity and expands the operational reading range of the sensor
3Ease of operation
If the magnet and detection circuit are not precisely aligned, then assembly is easier, but magnetic field induction intensity decreases
Solution Approach 1:
The patent introduces asymmetric features (ribs and grooves) on the magnet and corresponding features in the housing to create a unique angular positioning. This asymmetric design ensures precise alignment between the magnet and detection circuit while maintaining relatively simple assembly through the self-aligning nature of the complementary features
Solution Approach 2:
The complementary ribs and grooves create a self-aligning mechanism during assembly. The features guide the magnet into the correct angular position automatically, ensuring optimal magnetic field induction without requiring complex external alignment tools or procedures
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
The solution enhances magnetic field induction, reduces noise sensitivity, and widens the sensor's reading range, providing a more linear output signal while potentially lowering production costs by using ferrite instead of rare earth materials.
Implementation Method 1
one of the piston and the fixed part comprising a magnet with diametrical magnetization received in a housing, and the other of the piston and the fixture comprising a magnetic field detection circuit
Data Source
Figure 1~4
AI summary
The invention relates to a Hall effect linear position sensor for a motor vehicle, in particular for a clutch master cylinder of a motor vehicle, comprising a piston (20) translatably mobile relative to a stationary portion of the position sensor, either the piston (20) or the stationary portion comprising a magnet (22) with diametric magnetisation received in a recess (24), and the other one of the piston (20) and the stationary portion comprising a magnetic field detection circuit, the magnet (22) and the recess (24) being shaped so as to allow the insertion of the magnet (22) into the recess (24) only in angular positions of the magnet in which, when the magnet (22) is arranged axially at the detection circuit, the direction from the magnet (22) to the detection circuit is substantially parallel to the direction of the field lines in the magnet (22).