Fluid-Driven Stepper Motor With Asymmetric Teeth for MRI Use
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Solution Overview
Problem
Conventional stepper motors with electromagnetic components are unsuitable for environments with strong magnetic fields, such as MRI scanners, and hazardous chemical plants due to interference and safety concerns, as they can malfunction or cause sparks.
Innovation Solution
A stepper motor design utilizing a rotor fixed on a central shaft with cylindrical translators that translate axially, driven by pressurized gas or fluid, featuring asymmetric triangular teeth for rotation, allowing operation without electromagnetic interference, and can be made from non-ferromagnetic materials like PEEK for MRI compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic stepper motors are used, then the motor can operate with high precision and reliability, but it cannot be used in environments with strong magnetic fields or hazardous gases due to interference and safety concerns
Solution Approach 1:
The invention extracts and removes all electromagnetic components (coils, magnets, electrical windings) from the motor structure, replacing them with purely mechanical elements. This extraction eliminates the source of electromagnetic interference while maintaining the stepped rotation function through mechanical tooth engagement between rotor and stator components.
Solution Approach 2:
The invention replaces the electromagnetic actuation system with a purely mechanical drive system. Instead of using electromagnetic forces to rotate the rotor, the patent employs mechanically driven components such as cam mechanisms, gear trains, or direct mechanical actuators that engage with the rotor teeth, thereby substituting electromagnetic fields with mechanical force transmission.
2Measurement precision
If electromagnetic components are used in the motor, then precise control can be achieved, but sparks may be generated in hazardous environments
Solution Approach 1:
The invention extracts and removes all electromagnetic components (coils, magnets, electrical windings) from the motor structure, replacing them with purely mechanical elements. This extraction eliminates the source of electromagnetic interference while maintaining the stepped rotation function through mechanical tooth engagement between rotor and stator components.
Solution Approach 2:
The invention replaces the electromagnetic actuation system with a purely mechanical drive system. Instead of using electromagnetic forces to rotate the rotor, the patent employs mechanically driven components such as cam mechanisms, gear trains, or direct mechanical actuators that engage with the rotor teeth, thereby substituting electromagnetic fields with mechanical force transmission.
3Adaptability or versatility
If non-ferromagnetic materials are used for MRI compatibility, then the motor can operate in MRI scanners, but the material selection and manufacturing become more complex
Solution Approach 1:
The invention designs the motor structure and components to be universally compatible with non-ferromagnetic material requirements. By creating a modular architecture where the same mechanical principles apply regardless of specific material choices, the patent enables easy adaptation to different non-ferromagnetic materials (such as aluminum, titanium, or specialized polymers) without redesigning the core motor mechanism.
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
Enables reliable and safe operation in sensitive environments by using a gas-driven mechanism with asymmetric teeth for precise rotor control, minimizing frictional losses and electromagnetic interference, and can be used in MRI scanners and chemical plants.
Implementation Method 1
The translators can be moved by a pressure difference between the part of the cylindrical space between the housing and a translator and the part of the cylindrical space between the translator and the rotor
Implementation Method 2
a set of triangular asymmetric teeth located on the translator can interact and fit into a set of triangular asymmetric teeth on the rotor... the translator then exerts a normal axial force and a rotational tangential force on the rotor so that the rotor rotates
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
Stepper motor with a housing 1,2,4,6,16, in which a cylindrical rotor 11,15 fixed on a central shaft 12 can rotate but not translate along an axial direction. There are cylindrical translators 9, 14 on both sides of the rotors 11, 15, where the translators 9, 14 are sealed fit in a cylindrical space within the housing 6 and around the central shaft 12 and where the translators 9, 14 can only translate in an axial direction, where in one axial position of a translator 9, 14 a set of triangular asymmetric teeth 20 located on the translator 9, 14 can interact and fit into a set of triangular asymmetric teeth 21 on the rotor 11, 15, where the shape of the teeth 21 on both sides of the rotor 11, 15 is symmetric and where one of the sets of teeth 20, 21 between one translator 9 (14) and the rotor 11 (15) and a set of teeth 20, 21 between the other translator 9 (14) and the rotor 11 (15) are tangentially shifted, i.e. offset over a length equal to half the width of a tooth 20, 21 and where the translators 9, 14 can be moved by a pressure difference between the part of the cylindrical space between the housing 6 and a translator 9, 14 and the part of the cylindrical space between the translator 9, 14 and the rotor 11, 15.