Single-Phase Linear Motor with Variable Stator Cavity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electromagnetic linear motors are too large and complex for use in small optical systems like endoscopes, lacking precise positioning and requiring additional sensors for position determination, with multi-phase drives contributing to increased size and complexity.
Innovation Solution
A single-phase electromagnetic linear motor with a cylindrical stator made of soft magnetic material, featuring a variable cross-section cavity that generates reluctance forces for precise positioning, combined with Lorentz forces for controlled movement, using a single-phase electrical drive to minimize size and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multi-phase electromagnetic linear motor is used to achieve precise positioning, then positioning precision is improved, but device size and structural complexity increase
Solution Approach 1:
The patent extracts the position detection function from a separate sensor system and integrates it into the motor structure itself. The permanent magnet on the rotor interacts with the magnetic field from the stator coils to provide both actuation and position feedback, eliminating the need for external position sensors and reducing overall system complexity.
Solution Approach 2:
The stator coils serve dual functions: generating the magnetic field for actuation and providing the reference magnetic field for position detection. The permanent magnet on the rotor similarly serves both as the actuating element and as part of the position sensing mechanism, achieving multi-functionality that reduces device complexity.
2Measurement precision
If additional position sensors are added to determine rotor position, then positioning precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The motor system performs its own position detection using the magnetic fields already present in the actuation mechanism. The permanent magnet and stator coils work together to provide both motion control and position feedback, making the system self-sufficient and eliminating the need for separate sensing components.
3Measurement precision
If the stator is equipped with two coils and a permanent magnet as in prior art, then positioning capability is achieved, but stator size becomes very large
Solution Approach 1:
The patent modifies the magnetic circuit parameters and coil configuration to achieve the same positioning capability with a more compact stator design. By optimizing the magnetic path and field distribution, the motor achieves effective positioning with reduced stator dimensions compared to prior art configurations.
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 precise, continuous positioning of the rotor with low heating and minimal components, suitable for small optical systems, achieving stable positioning and efficient operation with a single voltage phase.
Implementation Method 1
The rotor is excited to translate in the stator by Lorentz or reluctance forces acting axially
Implementation Method 2
This configuration of the stator causes the magnetic resistance of a magnetic circuit, which is formed by the magnetic coil of the stator, the permanent magnet of the rotor and sections of the soft-magnetic hollow body, to vary with the position of the rotor in the axial direction. In the process, reluctance forces are generated in the axial direction, which force the rotor into a preferred, stable position.
Data Source
Figure 1~2
Figure 3~4
AI summary
An electromagnetic linear motor is proposed with an elongated stator (1), with a cylindrical hollow body (3) of the stator (1) made of a soft magnetic material, with a magnet coil (4) of the stator, with a rotor (2) that is linearly movable relative to the magnet coil (4) in the stator (1), with a permanent magnet (7, 10) of the rotor equipped with axial magnetization and with a shape or magnetic material property of the stator (1) that is variable in the axial direction.