Shaft Displacement Sensor with Convex Detection Element
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Solution Overview
Problem
Existing sensor technologies for determining shaft displacement along its longitudinal axis lack precision and reliability, especially when the shaft tilts, due to the influence of tilting angles on detection accuracy.
Innovation Solution
A sensor device with a radially arranged sensor unit and a convexly curved detection element, which is fixedly coupled to the shaft, generates a shaft displacement signal independent of tilting angles by varying the gap distance between the detection element and the sensor unit, utilizing magnetic fields or capacitive principles for precise displacement measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional sensor device is used to determine shaft displacement, then the device structure is simple, but the measurement precision deteriorates when the shaft tilts
Solution Approach 1:
The detection element is designed with a convex curved surface that protrudes toward the sensor unit. This curvature ensures that the gap distance between the detection element and sensor unit varies in a controlled manner that is independent of shaft tilting, allowing accurate displacement measurement even when the shaft is tilted. The curved surface creates a geometric relationship where the projection of the detection element onto the sensor unit plane remains consistent regardless of tilt angle.
Solution Approach 2:
The invention introduces a radial dimension by arranging the sensor unit radially relative to the shaft axis and positioning the detection element at a different radial distance. This dimensional arrangement creates a measurement system where the gap distance varies with displacement but remains independent of tilting, effectively separating the measurement of linear displacement from angular orientation.
2Reliability
If the sensor unit is arranged radially at a distance from the shaft axis, then the displacement measurement becomes independent of tilting angles, but the device complexity increases
Solution Approach 1:
The convex curved surface of the detection element works in conjunction with the radial arrangement to create a geometric configuration where measurement reliability is maintained. The curvature ensures that as the shaft tilts, the detection element's projection onto the sensor unit plane shifts in a predictable manner that does not affect the gap distance relationship, maintaining measurement reliability without requiring complex compensation mechanisms.
Solution Approach 2:
The invention changes the geometric parameters of the detection element by giving it a convex curved surface with specific radius of curvature. This parameter change creates a relationship where the gap distance between the detection element and sensor unit is determined by the radial positions and curvature, making the measurement independent of tilting angles and thereby improving reliability.
3Measurement precision
If the gap distance varies over the sensor unit extent, then the displacement can be determined independently of tilting angle, but the manufacturing precision requirements increase
Solution Approach 1:
While the convex curved surface does require manufacturing precision, the curvature radius can be designed to be relatively large, which reduces the stringency of manufacturing tolerances. The key requirement is that the curvature center coincides with the shaft axis, which can be achieved through standardized manufacturing processes. The varying gap distance is a direct geometric consequence of the curvature and radial arrangement, not an additional complexity.
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 sensor device achieves high precision and reliability in determining shaft displacement, even with tilting, allowing for simple and cost-effective manufacture and effective sealing, contributing to efficient operation of internal combustion engines like exhaust gas recirculation valves.
Implementation Method 1
utilizing magnetic fields or capacitive principles for precise displacement measurement
Implementation Method 2
utilizing magnetic fields or capacitive principles for precise displacement measurement
Data Source
AI summary
The present disclosure relates to sensor devices and the teachings may be applied to a sensor for determining a displacement of a shaft along its longitudinal axis. In some embodiments, a sensor device may include a sensor unit and a detection element. The sensor element is disposed at a fixed radial distance from the longitudinal axis. The detection element is arranged between the shaft and the sensor unit and coupled to the shaft. The side of the detection element facing away from the axis comprises a convex shape. A gap distance defined between the detection element and the sensor unit varies over an extent of the sensor unit perpendicularly with respect to the longitudinal axis and independently of a tilting angle of the shaft. The sensor unit generates a shaft displacement signal dependent on a displacement of the detection element in relation to the sensor unit along the longitudinal axis.