Linear Displacement Sensor with One-Dimensional Bearing
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Solution Overview
Problem
Existing linear displacement sensors in positioners like turbochargers and turbobrakes face challenges due to radial force components causing actuator deviation from linear displacement paths, leading to distorted sensing results and poor positional control.
Innovation Solution
A device featuring a movable magnet with a one-dimensional bearing that allows radial movement up to 15°, coupled with a fixed Hall sensor, maintains constant spacing and prevents distortion in displacement sensing, enabling precise position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rigid actuator guidance is used in known displacement sensor systems, then the actuator is constrained to follow a linear displacement path, but the system becomes unsuitable for positioners like turbochargers where radial force components cause natural drift
Solution Approach 1:
The magnet is made movable relative to the actuator through a one-dimensional bearing, allowing the sensing system to dynamically adapt to radial force components and actuator drift while maintaining accurate axial displacement measurement. This dynamic configuration resolves the contradiction by permitting controlled movement rather than rigid constraint.
2Device complexity
If the magnet is fixed rigidly to the actuator, then the displacement sensing is simple, but radial force components cause actuator deflection that distorts the sensing results
Solution Approach 1:
The sensing system is segmented into two independent functions: the one-dimensional bearing handles radial movements and positioning, while the Hall sensor measures only axial displacement. This segmentation allows the magnet to move radially without affecting measurement precision, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The one-dimensional bearing acts as an intermediary between the magnet and the actuator, decoupling radial force transmission from axial displacement measurement. This intermediary component allows the magnet to follow actuator drift radially while maintaining accurate axial position sensing.
3Adaptability or versatility
If the actuator is allowed to deflect radially to accommodate positioner forces, then adaptability improves, but the spacing between magnet and sensor varies causing sensing distortion
Solution Approach 1:
The system separates radial and axial dimensions functionally: the one-dimensional bearing manages radial dimension movements while the Hall sensor measures axial dimension displacement. This dimensional separation allows radial deflection without affecting axial measurement precision.
Solution Approach 2:
The one-dimensional bearing serves as an intermediary that absorbs radial movements, preventing them from transmitting to the magnet-sensor spacing. This intermediary maintains constant axial spacing while permitting radial adaptability.
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 ensures accurate linear displacement sensing and enhances positional control by allowing radial deflections while maintaining consistent magnet-to-sensor spacing, improving flexibility in positioner design and coupling with pneumatic servos.
Implementation Method 1
A bar magnet accommodated in the actuator is displaced relative to a fixed magnet sensor during positioning. The magnet sensor senses the position of the actuator from the change in the magnetic field
Data Source
AI summary
A device for sensing the linear axial displacement of an actuator comprises, in one embodiment, a movable, elongated magnet coupled to the actuator and a fixed Hall sensor. A one-dimensional bearing for the magnet is designed to receive bearing forces in a direction radial to the axial direction by permitting a displacement and pivoting movement of the magnet around the one-dimensional bearing. Arranging the Hall sensor in the region of the one-dimensional bearing ensures that the spacing or gap between the magnet and the Hall sensor remains constant, even in case of a pivoting and/or radial movement of the actuator and of the magnet connected thereto along the full length of displacement of the actuator. Accordingly, the results in sensing the linear displacement of the actuator are not adversely affected by admissible deflections of the actuator from the axial direction of linear displacement.