Electromagnetic Stroke Measurement With Guided Magnet Positioning
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Solution Overview
Problem
Existing electromagnetic stroke measuring systems suffer from inaccuracies due to relative movements of the magnet in directions other than the axial direction, which can lead to signal falsification and potential damage from moisture and dirt ingress.
Innovation Solution
A magnet holder with a guide that surrounds the magnet portion peripherally on at least three points, ensuring it moves only in the axial direction, while being protected from radial movements, and a sensor element is positioned to avoid contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the magnet holder is guided merely in a portion facing away from the magnet through a housing through-passage, then the magnet can be positioned to protrude in the direction of the sensor, but small relative movements in the peripheral direction of the plunger lead to comparatively larger relative movements of the magnet portion outside the through-passage
Solution Approach 1:
The magnet holder is divided into two functional portions: a guided portion that moves through the housing through-passage and is constrained in radial directions, and a magnet portion that protrudes toward the sensor. This segmentation allows the guided portion to maintain precise axial positioning while the magnet portion extends the required distance for sensor detection, thereby resolving the contradiction between protrusion distance and measurement accuracy.
2Length of moving object
If the magnet holder is guided merely in a portion facing away from the magnet, then the magnet can protrude in the direction of the sensor, but radial relative movements can also occur
Solution Approach 1:
The magnet holder is segmented into a guided portion constrained by the housing through-passage and a magnet portion free to protrude. The guided portion maintains radial stability while the magnet portion extends toward the sensor, resolving the contradiction between protrusion distance and positional stability.
Solution Approach 2:
The housing through-passage acts as an intermediary constraint that guides the magnet holder's motion. It allows axial movement while preventing radial deviations, thereby stabilizing the magnet holder's position and eliminating unwanted radial relative movements.
3Length of moving object
If the housing through-passage is used for guiding the magnet holder, then the magnet can be positioned for sensor detection, but the sensor is no longer separated from the guide space of the plunger by the housing, so moisture and dirt can pass through to the sensor
Solution Approach 1:
The sensor is extracted from the plunger guide space and positioned outside the housing. This separation removes the sensor from the contaminated environment while the magnet holder continues to be guided through the through-passage for proper positioning, thereby resolving the contradiction between magnet positioning and sensor protection.
Solution Approach 2:
The housing itself acts as an intermediary barrier between the contaminated guide space and the sensor. By positioning the sensor outside the housing while maintaining the through-passage for magnet holder guidance, the housing wall prevents moisture and dirt from reaching the sensor.
4Productivity
If the magnet is guided past the sensor in the axial direction during plunger stroke movement, then the stroke position can be detected, but relative movements of the magnet in other spatial directions falsify the signal
Solution Approach 1:
The magnet holder is segmented into a guided portion constrained by the housing through-passage and a magnet portion that moves axially with the plunger. This segmentation ensures that only axial movements are transmitted to the magnet, while radial movements are blocked, thereby maintaining signal accuracy during stroke detection.
Solution Approach 2:
The housing through-passage serves as an intermediary guide that filters the motion transmission. It allows axial movement of the magnet holder to follow the plunger stroke while blocking radial movements, ensuring that only valid axial position information is conveyed to the sensor.
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 configuration enhances measurement accuracy by preventing radial movements and protecting the sensor from contaminants, resulting in a more reliable stroke measurement.
Implementation Method 1
Electromagnetic stroke measuring systems which have, for example, a Hall sensor and a magnet can be used for measuring a stroke. The Hall sensor measures the magnetic field which emanates from the magnet.
Data Source
AI summary
An electromagnetic stroke measuring system, including: a plunger with a longitudinal axis pointing in the stroke direction, in which the plunger is arranged in a housing in the direction of the longitudinal axis and is movable in the direction of the longitudinal axis in the housing, a magnet holder with a magnet arranged in a magnet portion of the magnet holder, in which the magnet holder is arranged on a radial periphery of the plunger with respect to the longitudinal axis to be moved together with the plunger in the radial direction, and a sensor element which is arranged on a side of the housing facing away from the plunger with respect to the longitudinal axis, in which the housing forms a guide in which the magnet portion is guided in the direction of the longitudinal axis at least in portions. Also described is a related vehicle.