Rotary Adjustable Magnetic Spring With Linear Stroke Control
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Solution Overview
Problem
Existing adjustable-stiffness magnetic springs exhibit non-linear stroke length and require continuous power to maintain stiffness, limiting their application in ocean generators and robotic joints due to inefficiency and reliability issues.
Innovation Solution
A magnetic spring design with adjustable stiffness via magnet rotation, combined with a mechanical brake to maintain stiffness, providing a linear stroke length and enabling both positive and negative stiffness without mechanical springs, suitable for series connection to increase stroke length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current excitation is adjusted to change stiffness, then stiffness is adjustable, but continuous power is required to maintain stiffness
Solution Approach 1:
The patent uses periodic action by implementing a mechanical brake that is activated only when stiffness adjustment is needed, rather than requiring continuous power consumption. The brake is engaged to maintain the magnet's position at specific angular intervals, converting the continuous control problem into a periodic action that consumes energy only when necessary for adjustment or maintenance of stiffness.
Solution Approach 2:
The magnetic spring system utilizes the inherent magnetic field properties to maintain stiffness without external power input. Once the magnet is positioned at the desired angle using the mechanical brake, the magnetic repulsion/attraction forces naturally maintain the stiffness configuration without requiring continuous electrical excitation, allowing the system to serve itself.
2Adaptability or versatility
If direct magnet interface is used to create adjustable stiffness, then stiffness adjustment is achieved, but stroke length becomes highly non-linear
Solution Approach 1:
The patent transitions from linear stroke adjustment to angular rotation adjustment. Instead of moving the magnet linearly to change stiffness, the system rotates the magnet around the magnet assembly axis. This dimensional change from linear to angular space allows for linear stroke length characteristics while maintaining stiffness adjustability through angular position control of the magnet.
Solution Approach 2:
The system implements dynamic stiffness adjustment by allowing the magnet to rotate to different angular positions, where each angular position corresponds to a specific stiffness value. The mechanical brake provides dynamic locking at desired positions, enabling the system to adapt stiffness while maintaining linear stroke characteristics through the rotational degree of freedom.
3Adaptability or versatility
If mechanical springs are combined with magnet actuator to create negative stiffness, then variable stiffness is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the mechanical spring component from the traditional variable stiffness mechanism. By using only the magnet actuator with rotational adjustment and mechanical brake, the system achieves both positive and negative stiffness capabilities without requiring separate mechanical springs, thereby reducing device complexity while maintaining full variable stiffness functionality.
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
The design achieves high efficiency and reliability by reducing peak power requirements and increasing power generation capabilities in ocean generators, with improved linearity and longer service life.
Implementation Method 1
The adjustable stiffness magnetic spring includes a first cylindrical magnetic component and a second cylindrical magnetic component, where the first cylindrical magnetic component is rotatable about an axis and relative to the second cylindrical magnetic component to adjust a stiffness of the adjustable stiffness magnetic spring
Data Source
AI summary
Various examples of a variable stiffness magnetic spring with a linear stroke length are provided. The stiffness of the magnetic springs is varied through rotation of one or more magnets, and both positive and negative spring constants are achievable. In one example, a variable stiffness magnetic spring includes a first magnetic component and a second magnetic component, wherein the first magnetic component is coaxial with the second magnetic component, the first magnetic component is rotatable about an axis and relative to the second magnetic component to adjust a stiffness of the variable stiffness magnetic spring, and the second magnetic component is translatable along the axis and relative to the first magnetic component. While such variable stiffness magnetic springs exhibit highly linear stroke lengths, such variable stiffness magnetic springs can be positioned in series to achieve an even longer linear stroke length.