Electromagnetic Actuator Thrust Force via Magnetic Flux Cancellation
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Solution Overview
Problem
The existing electromagnetic actuators with a magnet on the movable element face a reduction in thrust force due to magnetic attraction forces acting opposite to the thrust direction, particularly at certain stages of the stroke, which hinders the improvement of thrust force.
Innovation Solution
The design includes a stator with a coil and a movable element made of soft magnetic material, where the permanent magnet is covered by the movable element core, forming a magnetic circuit that reduces the opposing magnetic attraction force, allowing for increased thrust force by managing magnetic flux direction and saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a permanent magnet is disposed on the movable element to increase thrust force, then the thrust force is improved, but a magnetic attraction force acts in the opposite direction at certain stroke positions, reducing the net thrust force improvement
Solution Approach 1:
A magnetic flux generating unit (coil) is introduced as an intermediary to generate magnetic flux that opposes and cancels the harmful magnetic attraction force between the permanent magnet and core case. This allows the permanent magnet to contribute to thrust force while the coil compensates for the opposing attraction force during specific stroke positions.
Solution Approach 2:
The magnetic flux generating unit dynamically adjusts the magnetic flux characteristics based on the movable element's position. By controlling the coil's magnetic flux in response to stroke position changes, the system optimizes the cancellation of harmful attraction forces while maintaining thrust force improvement throughout the stroke.
2Force
If the permanent magnet is positioned to maximize thrust force contribution, then thrust force is improved at start of stroke, but the permanent magnet creates magnetic resistance that hinders thrust force improvement in other stroke regions
Solution Approach 1:
The magnetic flux generating unit operates with feedback control based on the movable element's position. The system detects the position and adjusts the coil's magnetic flux accordingly, ensuring that the harmful attraction force is cancelled at the appropriate stroke positions while maintaining optimal thrust force throughout the entire stroke range.
Solution Approach 2:
The magnetic flux characteristics are made dynamic rather than static. The coil's magnetic flux automatically adapts to changing stroke positions, transitioning from cancelling attraction force at certain positions to allowing permanent magnet contribution at other positions, thereby maintaining consistent thrust force improvement throughout the stroke.
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 configuration significantly reduces the opposing magnetic attraction force, thereby enhancing the thrust force of the movable element across its operational stroke, improving overall performance and reducing magnetic resistance.
Implementation Method 1
an electromagnetic actuator configured to linearly move a movable element made of a magnetic material with an electromagnetic force
Implementation Method 2
a magnetic flux generated in the movable element by the permanent magnet flows in the same direction as a magnetic flux generated by the coil
Implementation Method 3
a magnetic flux generated in the movable element by the permanent magnet flows in the same direction as a magnetic flux generated by the coil. As a result, in addition to the magnetic flux generated by the coil, the magnetic flux generated by the permanent magnet contributes to the movable element, thereby increasing a thrust force
Data Source
AI summary
To obtain an electromagnetic actuator capable of improving a thrust force of a movable element. Provided is an electromagnetic actuator, including: a stator, which has a first surface at one end in an axial direction and a second surface at another end in the axial direction, and is made of a soft magnetic material having a tubular space formed in the axial direction; and a movable element, which is disposed in the tubular space, and is configured to move along the axial direction, wherein the stator includes: a coil; a core portion; and a protrusion portion, wherein the movable element includes a movable element core made of a soft magnetic material and a permanent magnet, and wherein at least one of a radially inner side and a radially outer side of the permanent magnet is covered by a movable element core.