Bridged Flexure Bearings for Non-Rotating Cryocooler Support

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Solution Overview

Problem

Conventional flexure bearings in cryocoolers allow moving components to rotate, causing disturbances and off-axis vibrations, which can lead to misalignment and operational issues.

Innovation Solution

Non-rotating flexure bearings with symmetric arms and bridges connecting adjacent sets of arms, preventing rotation and enhancing dynamic stability by dissipating unwanted harmonic motions through straining of bridges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional flexure bearings with spiral arms are used, then components can move freely, but rotation and off-axis vibrations occur causing disturbances

Engineering Contradiction:

Improvemovement freedomVSAvoidrotational stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The flexure bearing is segmented into multiple discrete arms (at least two arms) instead of a continuous spiral structure. Each arm is independently connected to the moving mechanism and support structure, allowing the system to restrict rotation while maintaining movement freedom through the segmented configuration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The arms are configured with asymmetric geometry relative to the central axis, where each arm has a different orientation angle. This asymmetric arrangement creates rotational stiffness that prevents off-axis vibrations and rotation while still allowing linear movement of the connected components

Inventive Principle:

Principle #4Asymmetry

2Stability of the object's composition

If symmetric flexure arms are used, then rotational stability improves, but dynamic stability is reduced due to unwanted harmonic motions

Engineering Contradiction:

Improverotational stabilityVSAvoiddynamic stability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

Multiple arms are merged into a single integrated flexure bearing assembly with at least two arms connected to both the moving mechanism and support structure. This combined configuration distributes harmonic motions across multiple arms, reducing unwanted vibrations and improving dynamic stability while maintaining rotational stability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The design converts potentially harmful harmonic motions into beneficial damping effects by configuring the arms and their connections to dissipate vibrational energy. The geometric arrangement and material properties of the arms transform harmful vibrations into controlled elastic deformations that reduce overall system disturbances

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If multiple arms are used to prevent rotation, then rotational stability improves, but device complexity increases

Engineering Contradiction:

Improverotational stabilityVSAvoidstructural complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

Each arm in the flexure bearing performs multiple functions simultaneously: it provides structural support, enables linear movement, restricts rotation, and dampens vibrations. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved rotational stability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The arms are designed as flexible structures with optimized thickness and geometry that provide the necessary mechanical properties without requiring bulky components. The thin-film-like construction of the arms reduces overall device complexity while maintaining the ability to prevent rotation and dampen vibrations through controlled flexibility

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution effectively secures components in place, minimizing rotation and off-axis vibrations, resulting in reduced exported disturbances and improved alignment, such as keeping compressor pistons aligned with their bores, and enhancing the operational stability of cryocoolers.

Implementation Method 1

multiple bridges, where each bridge connects one of the flexure arms in one set of flexure arms to one of the flexure arms in an adjacent set of flexure arms

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

enhancing dynamic stability by dissipating unwanted harmonic motions through straining of bridges

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentUS10234075B2Non-rotating flexure bearings with enhanced dynamic stability for cryocoolers and other devices

Publication Date: 2019.03.19 RAYTHEON CO

AI summary

A system includes a device, a support structure, and a flexure bearing configured to connect the device to the support structure. The flexure bearing includes an outer hub and an inner hub, where the hubs are configured to be secured to the support structure and to the device. The flexure bearing also includes multiple sets of flexure arms connecting the outer hub and the inner hub, where each set of flexure arms includes symmetric flexure arms. The flexure bearing further includes multiple bridges, where each bridge connects one of the flexure arms in one set of flexure arms to one of the flexure arms in an adjacent set of flexure arms.