Linear Voice Coil Actuator Bidirectional Electromagnetic Spring
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Solution Overview
Problem
Existing linear voice coil actuators with moving magnets lack bidirectional electromagnetic spring characteristics, limiting their mechanical performance and versatility.
Innovation Solution
The solution involves selecting appropriate relative dimensions of the housing and field assembly, and optionally using a radially magnetized magnet or soft magnetic extension, along with controlled current application to the coil assembly, to create predetermined bidirectional spring characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional linear voice coil actuator design is used with minimized housing length, then the actuator achieves compact size, but it lacks bidirectional spring characteristics
Solution Approach 1:
The patent applies parameter changes by deliberately selecting specific relative dimensions between the housing length Lh and field assembly length Lf, and by positioning the coil assembly at an offset from the field assembly center. These parameter modifications create bidirectional electromagnetic spring characteristics without requiring additional mechanical springs, thereby achieving enhanced adaptability while maintaining compact dimensions.
Solution Approach 2:
The patent makes the housing and magnetic circuit components serve multiple functions: they provide structural support, guide the field assembly, and simultaneously generate electromagnetic spring forces in both directions. This multi-functionality eliminates the need for separate mechanical spring components, achieving bidirectional spring characteristics within the existing actuator structure.
2Adaptability or versatility
If coil assembly is positioned at the center of the housing, then the actuator achieves symmetric structure, but it cannot provide bidirectional spring characteristics
Solution Approach 1:
The patent deliberately introduces asymmetry by positioning the coil assembly at an offset distance from the center of the field assembly. This asymmetric positioning creates different magnetic flux paths and force characteristics in opposite directions, enabling bidirectional spring behavior. The offset distance is carefully selected to achieve the desired force characteristics while maintaining a relatively simple single-coil structure.
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 approach enables the creation of linear voice coil actuators with adjustable spring-like characteristics, allowing for bidirectional force application and reduced need for mechanical springs, enhancing mechanical performance and versatility.
Implementation Method 1
linear voice coil actuators of the type with moving magnets, a moving field assembly is utilized along with a stationary coil assembly
Implementation Method 2
The field assembly is typically comprised of an axially magnetized cylindrical magnet, sandwiched between two soft magnetic pole pieces
Data Source
AI summary
“Electromagnetic spring” characteristics can be obtained in a voice coil actuator by deliberately selecting some or all of geometry, location of the housing, field assembly and coils, and/or magnitude and direction of the current applied to the coils; for example, predetermined bidirectional spring characteristics can be provided by appropriate deliberate selection of the relative dimensions of the housing and field assembly, and the spring characteristics can be further altered though the addition of structures, such as a radially magnetized magnet, or a soft magnetic extension, positioned at an end of the housing, and/or by applying current of a selected magnitude and direction to the coil assembly.