Asymmetric Coil Linear Actuation for Longer Stroke Profiles
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Solution Overview
Problem
Existing solenoid linear actuators have limited stroke length due to uniform magnetic field distribution, which restricts their application in scenarios requiring nonlinear forces or longer strokes.
Innovation Solution
The implementation of asymmetric layered-coil geometry or multiple coils with varying current levels to create a nonuniform magnetic field distribution, allowing for longer strokes without increasing the coil length, and the use of mechanical stops to control the plunger's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a uniform magnetic field distribution is used in solenoid linear actuators, then the magnetic force is linear along the stroke, but the stroke length is limited to half the coil length
Solution Approach 1:
The patent applies asymmetry by using multiple coils with different numbers of turns distributed asymmetrically along the actuator length. The first coil has a different number of turns than the second coil, creating a nonuniform magnetic field distribution that enables the plunger to travel beyond the midpoint of the actuator, achieving a stroke length greater than half the coil length while maintaining controllable force characteristics
2Length of moving object
If the coil length is increased to achieve longer stroke, then the stroke length increases, but the device complexity and size increase
Solution Approach 1:
The patent segments the magnetic field generation function into multiple separate coils (first coil and second coil) with different numbers of turns. This segmentation allows each coil to contribute differently to the overall magnetic field distribution, enabling longer stroke without requiring a single excessively long coil, thus managing device complexity through modular coil design
Solution Approach 2:
The patent implements local quality by assigning different numbers of turns to different coils at different positions along the actuator. The first coil has a specific number of turns optimized for its position, while the second coil has a different number of turns optimized for its position, creating locally optimized magnetic field contributions that collectively achieve the desired long-stroke performance
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 enables linear actuators to achieve longer strokes and nonlinear force profiles, enhancing their applicability in applications like crushing, stretching, and smooth speed transitions, while maintaining control over the plunger's position and motion.
Implementation Method 1
a current-carrying conductor, which by Oersted's Law generates a magnetic field (given by Biot-Savart), interacts with an external magnetic field, and thus, a force on both the conductor and a source of the external magnetic field is generated
Implementation Method 2
a current-carrying conductor, which by Oersted's Law generates a magnetic field (given by Biot-Savart), interacts with an external magnetic field, and thus, a force on both the conductor and a source of the external magnetic field is generated
Implementation Method 3
one or more coils arranged to provide a nonuniform (asymmetric) field distribution
Data Source
AI summary
Apparatus, systems, and methods used to produce linear and rotational motion, acceleration, and actuation by the use of mobile ferromagnetic or permanent magnets subjected to asymmetric electromagnetic field distributions are disclosed herein. A variety of exemplary embodiments and applications are described, involving different coil and actuator geometries to include and allow for both stationary and moving magnets, electric fields, and magnetic fields.