Cryocooler split flexure suspension system and method
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Solution Overview
Problem
Cryogenic coolers face challenges in minimizing package volume and mass while maintaining mechanical advantage to prevent sag of cantilevered masses under external forces, particularly in Stirling cryocoolers where traditional flexure suspension systems require significant spacing, increasing overall length.
Innovation Solution
A suspension system that splits two independently moving flexure systems across a single magnetic structure, using concentrically oriented flexure connecting shafts and connectors to allow the motor's magnetic circuit to occupy the space between flexure stacks, reducing package size and maintaining resistance to sag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If flexure stacks are spaced apart to provide sufficient radial stiffness and prevent sag of cantilevered masses, then mechanical stability is improved, but package volume and overall length increase
Solution Approach 1:
The patent applies nesting by placing the magnetic circuit structure inside the space between the two flexure stacks, with the magnetic circuit nested within the annular region formed by the flexure assembly. This allows the magnetic circuit to occupy the otherwise unused space, reducing package volume while maintaining the radial stiffness provided by the spaced flexure stacks
Solution Approach 2:
The patent transitions from a linear arrangement where flexure stacks are spaced along the longitudinal axis to a radial arrangement where the magnetic circuit is positioned in the annular space between the flexure stacks. This dimensional reorganization allows simultaneous achievement of mechanical stability (through proper flexure spacing) and compact packaging (by utilizing radial space efficiently)
2Manufacturing precision
If flexure stacks are spaced apart to maintain alignment of moving elements, then alignment precision is improved, but device length increases
Solution Approach 1:
The magnetic circuit is nested within the space between flexure stacks, allowing the flexure stacks to be positioned at optimal distances for alignment precision without increasing overall device length, as the magnetic circuit utilizes the interstitial space
3Adaptability or versatility
If mass is cantilevered away from the flexure system to accommodate motor design, then motor functionality is improved, but susceptibility to sag increases
Solution Approach 1:
The patent employs counterbalancing by positioning the magnetic circuit structure to provide structural support that counteracts the sagging tendency of cantilevered masses. The magnetic circuit assembly acts as a counterweight structure that maintains mechanical balance and reduces sag under external forces
Data Source
AI summary
Conventional Stirling cycle cryogenic coolers comprise two linear motors (22), one for the displacer piston and one for the compressor piston. The' invention is about a Stirling cycle cryogenic cooler with.only a single linear motor (22). First (12) and second (14) flexure bearings are connected to an inner tube (28) which is fixed to the compressor piston (not shown). Third (18) and fourth (16) flexure bearings are connected to an outer tube (32) which is fixed to the displacer piston (not shown). The linear mo.tor (22) is arranged between the first (12) and second (14) flexure bearings as well as between the third (18) and fourth (16) flexure bearings. The inner tube (28) is driven by a first element (24) of the linear motor (22), the outer tube (32) by a second element (26).