Laser Welded Sensor Cover for Leak Tight Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic field sensitive sensors face service life issues due to housing leaks, which allow humidity to penetrate and cause erroneous measurements or damage, particularly under harsh environmental conditions, as traditional sealing methods like threading or gluing are unreliable due to temperature and chemical factors.
Innovation Solution
A laser-welded housing design with a rotationally symmetrical pot-shaped housing and a thin, circular disc cover made from non-magnetizable metal, ensuring a secure seal and minimizing temperature-induced damage, with a CNC-controlled welding process and additional sealing measures like a cable outlet and intermediary pot for reduced heat conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional sealing methods like threading or gluing are used to seal the housing, then the housing can be assembled with standard methods, but the sealing reliability deteriorates under harsh environmental conditions like high temperature and aggressive chemicals
Solution Approach 1:
The patent replaces traditional mechanical sealing methods (threading, gluing) with laser welding technology. The laser welding process creates a permanent, reliable seal that is resistant to high temperatures and aggressive chemicals, eliminating the sealing failures associated with mechanical assembly methods while maintaining ease of manufacture through automated welding processes.
Solution Approach 2:
The patent changes the sealing mechanism from mechanical/chemical bonds to thermal fusion bonds through laser welding. By controlling laser parameters (power, speed, focus position), the process creates a weld seam with optimal strength and seal integrity that maintains reliability under harsh environmental conditions while allowing for automated manufacturing.
2Reliability
If laser welding is used to seal the housing, then the sealing reliability is improved, but temperature induction may damage the sensor element or circuit board
Solution Approach 1:
The patent introduces an intermediary pot (shielding structure) positioned between the laser welding zone and the sensor element/circuit board. This intermediary component absorbs or deflects excess heat and thermal radiation, protecting the sensitive electronics from temperature damage while allowing the laser welding process to proceed and create a reliable seal on the housing cover.
Solution Approach 2:
The patent positions the sensor element and circuit board at predetermined safe distances from the welding zone before the laser welding process begins. This preliminary arrangement ensures that when welding occurs, the sensitive components are already in protected positions, preventing temperature-induced damage while maintaining the integrity of the seal.
3Reliability
If the cover is made thin to allow magnetic field permeation, then the magnetic field transmission is improved, but the structural stability of the cover deteriorates
Solution Approach 1:
The patent merges the cover and housing into a unified structure through laser welding, creating an integrated sealed enclosure. The weld seam provides both sealing functionality and structural reinforcement, compensating for the reduced thickness of the cover while maintaining structural stability. The combination of the thin cover and welded housing creates an optimal balance between magnetic field permeation and mechanical strength.
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 provides a long-lasting, secure seal for magnetic field sensitive sensors, preventing humidity ingress and maintaining accurate measurements by minimizing temperature-induced damage and ensuring a stable, reliable housing structure.
Implementation Method 1
the cover (3) is welded to the housing (2) through a laser
Implementation Method 2
the pot shaped housing (2) is configured rotation symmetrical and the cover (3) is a circular disc and the welding process is performed under CNC control with a velocity that is as even as possible
Implementation Method 3
Both components are preferably made from metal, in particular the same metal, preferably a non-magnetizable metal so that the magnetic field of an encoder magnet positioned outside of the housing can permeate the cover without problems towards the sensor element arranged in the housing
Implementation Method 4
the welding process is performed under CNC control with a velocity that is as even as possible
Implementation Method 5
the cover (3) is a circular disc and the welding process is performed under CNC control with a velocity that is as even as possible. Both components are preferably made from metal, in particular the same metal, preferably a non-magnetizable metal so that the magnetic field of an encoder magnet positioned outside of the housing can permeate the cover without problems towards the sensor element arranged in the housing
Data Source
AI summary
In order to configure a housing of a sensor, in particular of an angle sensor, long term leak tight in the best way possible a cover is not glued into the pot shaped housing or screwed in and sealed, but welded in the housing through a laser. In spite of the sensor chip already being in the housing, the heat induction is so small that the sensor chip is not damaged even though the sensor chip is very small.