Hollow Ferromagnetic Core Sensor for Axis Alignment
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Solution Overview
Problem
Current magnetic tracking systems for medical instruments face challenges in maintaining the alignment of magnetic and physical axes, leading to imaging errors and fragility issues during assembly, which affect the accuracy and reliability of instrument positioning within anatomical features.
Innovation Solution
A magnetic field sensor assembly with a hollow core made of ferromagnetic material, where conductive material forms a coil with terminations positioned within the core, allowing for secure connection and alignment of lead wires, reducing fragility and improving axis alignment through magnetic shielding, enabling precise position measurement within an electromagnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional magnetic sensor assembly methods are used, then assembly is simpler, but axis alignment accuracy deteriorates leading to imaging errors
Solution Approach 1:
A hollow ferromagnetic core is introduced as an intermediary component between the coil and the external environment. This core serves as a magnetic shield that guides and concentrates magnetic field lines, ensuring that the magnetic axis aligns with the physical axis of the sensor assembly. The core's internal cavity accommodates lead wires and terminations, providing a structured pathway that simplifies assembly while maintaining alignment precision.
Solution Approach 2:
The sensor assembly employs composite construction by combining ferromagnetic material (the hollow core) with non-magnetic materials (coil windings, lead wires, and housing). This composite structure allows the ferromagnetic core to provide magnetic field guidance and shielding, while the non-magnetic components provide electrical functionality and mechanical support, achieving both alignment accuracy and assembly simplicity.
2Strength
If terminations are positioned outside the core, then assembly is easier, but mechanical strength and fragility resistance deteriorate
Solution Approach 1:
The hollow ferromagnetic core functions as a nested structure that contains and protects the lead wires and terminations within its internal cavity. This nesting arrangement provides mechanical strength by enclosing fragile components within a rigid ferromagnetic shell, while the open ends of the core allow for easy insertion and connection of wires during assembly.
Solution Approach 2:
The hollow core provides localized protection and structural support precisely where the terminations and lead wire connections are positioned. The ferromagnetic material concentrates its protective and guiding properties at the termination points, reinforcing mechanical strength where needed most while maintaining overall assembly simplicity.
3Measurement precision
If additional calibration steps are added, then measurement precision improves, but productivity deteriorates
Solution Approach 1:
The hollow ferromagnetic core is pre-configured with its internal cavity and geometric properties during manufacturing to inherently provide magnetic field guidance and axis alignment. This preliminary structuring of the core ensures that the magnetic axis aligns with the physical axis without requiring additional calibration steps during system setup or operation.
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 enhances the alignment of magnetic and physical axes, reducing imaging errors and increasing the mechanical strength of the sensor assembly, allowing for accurate tracking and navigation of instruments within complex anatomical structures without additional calibration steps.
Implementation Method 1
improving the alignment of magnetic and physical axes through magnetic shielding
Implementation Method 2
If an instrument with an included sensor is placed within a varying electromagnetic field, a voltage can be generated in the electromagnetic sensor
Data Source
AI summary
A magnetic field sensor assembly includes a hollow cylindrical core, conductive material and at least first and second lead wires. The hollow cylindrical core is made of ferromagnetic material and has a proximal end and a distal end. The conductive material is disposed around the hollow cylindrical core and forms at least one turn of a coil that has at least one start terminal and at least one finish terminal. The first and second lead wires pass through the center of the hollow cylindrical core and the first lead wire is connected to the start terminal thereby forming a first termination and the second lead wire is connected to the finish terminal thereby forming a second termination. The first and second terminations are positioned within the hollow cylindrical core.