Folded Spring Flexure Suspension for Linear Motors
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Solution Overview
Problem
Existing suspension systems for linearly-reciprocating mechanisms, such as electromagnetic actuators and inertial masses, face challenges with friction, efficiency loss, wear, and harmonic distortion due to the use of bearings and non-metallic materials, which are not suitable for demanding applications like aerospace where stiffer flexure systems are required.
Innovation Solution
A folded flat spring flexure system is developed, utilizing a stack of identical flat springs with balanced array members to provide uniform compliance and cancel lateral flexure stresses, eliminating the need for bearings and ensuring precise straight-line movement with reduced mass and increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bearings and coil springs are used to support the reciprocating mass, then the mass can be supported and positioned within the stroke length, but friction and efficiency loss occur
Solution Approach 1:
The patent replaces the mechanical bearing and coil spring suspension system with an electromagnetic suspension system. The electromagnetic actuator uses magnetic fields to suspend and position the reciprocating mass without physical contact, eliminating friction and energy loss associated with mechanical bearings and springs while maintaining reliable support and positioning within the stroke length.
2Reliability
If bearings are used to support the reciprocating mass, then the mass can be constrained to move along the central axis, but wear deterioration occurs over time
Solution Approach 1:
The patent eliminates mechanical bearings by using an electromagnetic field-based suspension system. The magnetic forces constrain the reciprocating mass to move along the central axis without physical contact, removing wear and deterioration issues while maintaining reliable axial constraint throughout the device's operational life.
3Adaptability or versatility
If non-metallic resilient materials are used for flexure, then the material can stretch to allow radial variations, but durability and stability are insufficient
Solution Approach 1:
The patent replaces mechanical flexure elements made of non-metallic resilient materials with an electromagnetic suspension system. The magnetic field provides the necessary compliance and geometric adaptability to accommodate radial variations during stroke while eliminating the durability and stability problems inherent in non-metallic materials.
4Loss of energy
If a folded flat spring flexure system is used to eliminate bearings, then friction and wear are eliminated, but the system complexity increases
Solution Approach 1:
The patent merges the suspension and actuation functions into a single integrated electromagnetic system. The electromagnetic actuator simultaneously provides the driving force for reciprocation and the suspension/positioning function, eliminating the need for separate bearing and spring components while reducing overall system complexity despite the folded flat spring flexure design.
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 folded flexure system enhances operational efficiency, reliability, and cost-effectiveness while maintaining structural balance and minimizing unwanted vibrations, making it suitable for a wide range of applications including active vibration control and suppression.
Implementation Method 1
a first end region of the central span element and outer span elements being firmly clamped between two bolted pressure plates of a yoke/idler fastening providing firm and well-defined contact pressure on the flat springs so as to accurately define uniform effective compliant span length
Implementation Method 2
electromagnetic actuators, oscillating drivers and the like
Data Source
AI summary
A family of flexure suspension systems for reciprocating linear motors, especially voice coil type, wherein basic flexure span elements, each a flat spring or typically a stack thereof, are arranged in a folded flexure configuration to suspend a moving armature from a base in a compliant manner with a precise linear stroke path along a central axis. Typically two tiers of folded flexures suspend the armature, each tier having at least two array members, each a balanced quad or triad side-by-side row of span elements, disposed in a plane about the central axis in a polar/radial or rectangular pattern. Inherent overall balance and cancellation of unwanted forces acting on the system components achieve a consistent operating air gap, eliminate undesired torque imposed on the armature, coil, and entire mechanical assembly, and reduce mass and space requirements.