Cylinder Rod Position Sensing via Laser Welds
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Solution Overview
Problem
The existing methods for position sensing in large cylinder rods, which involve machining ferromagnetic materials and applying corrosion-resistant coatings, are time-consuming, expensive, and limit the coating thickness, reducing the rod's lifespan due to the complexity of forming gear teeth and applying non-magnetic coatings.
Innovation Solution
The method involves depositing non-ferromagnetic welds along the cylinder rod's length and applying a corrosion-resistant material by laser cladding, allowing for position sensing using eddy current or magnetic field probes to detect changes in magnetic properties, electric properties, and physical geometry, thereby enhancing resolution and coating thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gear teeth grooves are individually machined on the cylinder rod to increase position sensing resolution, then measurement precision is improved, but manufacturing time and cost increase significantly
Solution Approach 1:
The invention segments the continuous gear tooth profile into discrete, individually addressable features by using circumferential welds instead of continuous grooves. Each weld acts as an independent position marker that can be detected by the sensor, providing the same resolution benefit while eliminating the time-consuming continuous machining process.
Solution Approach 2:
The invention replaces the mechanical machining process with a welding process to create the gear tooth profile markers. Instead of removing material through complex groove machining, the system uses circumferential welds deposited on the cylinder rod surface, which are then detected by magnetic or eddy current sensors, substituting mechanical fabrication with a more efficient deposition and detection system.
2Reliability
If a corrosion resistant coating is applied over the gear teeth to protect the cylinder rod, then reliability is improved, but the coating thickness is limited due to reduced sensor detection ability
Solution Approach 1:
The invention changes the detection parameters by using non-contact magnetic field sensing or eddy current sensing through the corrosion resistant coating, rather than direct mechanical or optical contact. This allows the sensor to detect the gear tooth profile markers through the coating material, enabling thicker corrosion protective layers without compromising position sensing capability.
Solution Approach 2:
The corrosion resistant coating acts as an intermediary layer between the gear tooth profile markers and the sensor. Instead of requiring direct contact between the sensor and the ferromagnetic surface, the magnetic field or eddy current sensor can detect the markers through this intermediate coating layer, allowing the coating to serve its protective function while maintaining sensing capability.
3Duration of action of stationary object
If non-magnetic coating layers are applied to protect the gear teeth, then the cylinder rod lifespan is extended, but the sensor's ability to detect gear teeth is reduced
Solution Approach 1:
The invention replaces direct mechanical detection methods with non-contact magnetic field or eddy current sensing that can penetrate non-magnetic coating layers. The circumferential welds create magnetic field disturbances or eddy current patterns that can be detected through the non-magnetic coating, maintaining position sensing capability while allowing extensive corrosion protection.
Solution Approach 2:
The invention changes the sensing modality from surface-contact-based detection to field-based detection that can operate through coating layers. By using magnetic field sensors or eddy current probes that sense through the non-magnetic coating material, the system maintains detection capability while the coating provides extended protection and lifespan.
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 approach reduces manufacturing time and cost, increases the thickness of the corrosion-resistant coating, and improves the lifespan of the cylinder rod by enabling more precise position sensing and damage detection.
Implementation Method 1
The sensor assembly measures a change in magnetic properties of the cylinder rod to detect at least one of a change in position of the cylinder rod and damage to the cylinder rod
Implementation Method 2
The eddy current or magnetic field probe measures a change in one of magnetic properties, electric properties and physical geometry of the cylinder rod to detect a change in position of the cylinder rod
Data Source
AI summary
A method for detecting a position of a cylinder rod includes depositing a plurality of welds substantially along the length of a steel rod and depositing a corrosion resistant material onto the steel rod by laser cladding. The cylinder rod is then placed proximate to a sensor assembly. One of the cylinder rod and the sensor assembly are moved relative to the other. The sensor assembly detects a change in properties between the steel rod and the welds and generates a corresponding signal. A change in position of the cylinder rod or damage to the cylinder rod can be detected by analyzing the number and strength of the signals.