Electromagnetic Linear Stepper Motor for Endoscope Positioning
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Solution Overview
Problem
Existing linear motors for endoscopic applications are too large and complex, requiring additional position sensors and generating significant heat due to high power loss, making them unsuitable for miniaturization and precise positioning of optical components without obstructing the beam path.
Innovation Solution
A compact linear stepping motor with a stator and rotor design that allows for N stable positions without a position sensor, using reluctance forces and stator pole shoes to achieve precise positioning, and minimizing heat generation through low energy consumption, with a simple geometric design for easy manufacturing and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear drive with permanent magnet and solenoid coils is used to adjust focal length, then positioning capability is achieved, but the device size increases and requires additional position sensors
Solution Approach 1:
The rotor's permanent magnet and pole shoes automatically generate N stable positions through magnetic reluctance forces with the stator pole shoes, enabling the system to self-determine position without external sensors. The magnetic circuit inherently provides positioning information through its stable equilibrium states.
Solution Approach 2:
The patent replaces sensor-based position detection with a magnetic field-based positioning system. Instead of using mechanical or electronic sensors to detect rotor position, the system uses the magnetic reluctance interaction between permanent magnets and pole shoes to create discrete stable positions that inherently encode position information.
2Volume of moving object
If conventional linear motors are miniaturized for endoscope tips, then device size is reduced, but heat generation increases due to high power loss
Solution Approach 1:
The motor operates by sequentially energizing coils in a periodic pattern to generate a traveling magnetic field. This periodic energization creates discrete stable positions that the rotor naturally occupies, reducing continuous power consumption compared to conventional motors that require constant current for position holding.
Solution Approach 2:
The patent changes the operational parameters by using magnetic reluctance forces instead of continuous electromagnetic force. The system transitions from continuous power consumption to intermittent power delivery, only energizing coils when transitioning between stable positions, thereby reducing overall power loss and heat generation.
3Measurement precision
If stator pole shoes are arranged in dense grid to increase positioning resolution, then positioning precision is improved, but manufacturing complexity increases
Solution Approach 1:
The stator pole shoes are segmented into discrete units arranged in a grid pattern, with each pole shoe being a simple geometric element. This segmentation allows the complex positioning function to be achieved through repetition of simple, easily manufacturable components rather than requiring precision machining of complex shapes.
Solution Approach 2:
The stator pole shoes are designed with uniform geometry and identical magnetic properties, creating a homogeneous array. This homogeneity simplifies manufacturing by allowing mass production of identical components that can be assembled through simple repetitive processes, while the collective arrangement provides high positioning resolution.
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 fast, continuous, and exact positioning of optical components with low energy consumption and minimal heat generation, allowing for miniaturization to fit within endoscopes while maintaining high positioning accuracy and rigidity.
Implementation Method 1
The rotor has at least one permanent magnet with rotor pole shoes on each side of the permanent magnet
Implementation Method 2
By energizing the at least one coil, the runner can be shifted within the stator between the various stable rest positions
Implementation Method 3
at least one coil is arranged between two stator pole shoes. By energizing the at least one coil, the runner can be shifted
Implementation Method 4
Due to the reluctance forces, the rotor assumes stable rest positions within the stator
Data Source
Figure 1~2
Figure 3~4
Figure 5~8
AI summary
The motor has a rotationally symmetrical stator (8) including multiple stator pole pieces (2a-2e) which are enclosed by a magnetic guiding element (10) and arranged in equal distance. Coils (3a, 3b) are located between two adjacent stator pole pieces, and a rotationally symmetrical rotor (9) is enclosed by the stator in a radial direction and includes a permanent magnet (7) with rotor pole pieces (6a, 6b) on each side. The magnet is magnetized parallel to the stator. An optical element is accommodated within the rotor, and a sliding sleeve is arranged between the stator and the rotor. An independent claim is also included for a method for operating an electromagnetic linear stepper motor.