Magnet Holder Guidance for Accurate Electromagnetic Stroke Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromagnetic stroke measurement systems in brake modules suffer from measurement inaccuracies due to undesirable relative movements of the magnet in lateral and radial directions, which distort the signal and expose the sensor to contaminants, leading to potential damage.
Innovation Solution
An electromagnetic stroke measuring system with a magnet holder that guides the magnet along the plunger's longitudinal axis, ensuring minimal relative movements in other directions, and a sensor element protected by a full-surface guide, preventing contamination and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnet holder is only guided in a section facing away from the magnet, then the magnetic section can project towards the sensor for measurement, but small relative movements in the circumferential direction lead to proportionally larger relative movements of the magnetic section, and radial relative movements can occur, distorting the measurement signal
Solution Approach 1:
The patent transitions from partial guidance to full-surface guidance, adding guidance in the radial dimension. The guide surface is designed to extend over the entire circumference of the plunger, preventing radial and circumferential movements while allowing axial stroke measurement. This dimensional expansion of the guidance system eliminates unwanted magnet movements that distort the measurement signal.
2Measurement precision
If the magnetic holder is fully guided by the housing, then measurement accuracy is improved, but the sensor is no longer separated from the plunger's guide space by the housing opening, allowing moisture and contaminants to reach the sensor
Solution Approach 1:
The patent introduces a guide surface as an intermediary element between the magnet holder and the sensor. This guide surface provides the necessary mechanical guidance for accurate measurement while simultaneously acting as a protective barrier that prevents moisture and contaminants from reaching the sensor. The guide surface mediates between the conflicting requirements of full guidance for accuracy and sensor protection from environmental factors.
3Reliability
If the guide surface extends over the entire circumference of the plunger, then radial and circumferential movements are prevented, but the complexity of the housing structure increases
Solution Approach 1:
The patent designs the guide surface to serve multiple functions simultaneously: it provides radial and circumferential guidance for the magnet holder, ensures accurate axial stroke measurement, and protects the sensor from contaminants. By making the guide surface universal and multi-functional, the patent reduces the need for separate components for each function, thereby managing structural complexity while achieving reliable magnet position stability.
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 system provides reliable and accurate stroke measurements by compensating for non-axial movements and protecting the sensor from environmental factors, thereby improving safety and reliability in applications like foot brake modules.
Implementation Method 1
The sensor element (2) is arranged on a side of the housing (1) facing away from the plunger (5) with respect to the longitudinal axis (L). The sensor element detects the magnetic field strength of the magnet (4)
Implementation Method 2
EP 3 620 754 A1 discloses a magnetic holder that has a holding section circumferentially enclosing the plunger... The Hall sensor measures the magnetic field emanating from the magnet. Changes in the magnetic field around the Hall sensor are detected
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an electromagnetic stroke measuring system, having: a plunger (5) with a longitudinal axis (L) pointing in the stroke direction, wherein the plunger (5) is arranged in a housing (1) in the direction of the longitudinal axis (L) and can be moved in the direction of the longitudinal axis (L) in said housing, a magnet holder (3) with a magnet (4) arranged in a magnet portion (3a) of the magnet holder (3), wherein the magnet holder (3) is arranged on a radial periphery of the plunger (5) with respect to the longitudinal axis (L) in order to be moved together with the plunger (5) in the radial direction, and a sensor element (2) which is arranged on a side of the housing (1) facing away from the plunger (5) with respect to the longitudinal axis (L), wherein the housing (1) forms a guide (1a) in which the magnet portion (3a) is guided in the direction of the longitudinal axis (L) at least in portions.