Dual-Axis Flexure Gimbal for Frictionless Precision Tip-Tilt
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Solution Overview
Problem
Mechanisms requiring two-axis pivot capability often face issues with wear, slop, and limited life due to the use of universal joint couplers with ball bearings or bushings, which are costly to overcome, especially in high-precision applications like steering mirrors or scan mirrors.
Innovation Solution
A dual-axis flexure gimbal device utilizing a flexure spring mass body with a flexure unit that provides two rotational degrees of freedom without friction, using a combination of slots and a flexible diaphragm to restrict movement in other degrees of freedom, allowing for precise tip-tilt motion of optical mirrors without lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If universal joint couplers with ball bearings or bushings are used to achieve two-axis pivot capability, then the mechanism can pivot between moving bodies, but wear, slop, and limited life occur due to friction and contact surface displacement
Solution Approach 1:
The patent replaces the traditional mechanical bearing system (ball bearings or bushings) with a flexure pivot system that uses elastic deformation of flexural elements to achieve pivot motion. This substitution eliminates contact surface displacement and friction-based wear, thereby extending mechanism service life and improving reliability in high-precision applications.
Solution Approach 2:
The invention changes the fundamental operating parameter from contact-based mechanical pivoting to elastic flexing. By utilizing the elastic properties of flexural elements, the system achieves pivot capability without the wear and slop associated with traditional bearings, effectively extending the duration of action.
2Ease of operation
If ball bearings or bushings are used in universal joint couplers, then two-axis pivot motion is enabled, but friction and the need for lubrication increase complexity and maintenance requirements
Solution Approach 1:
The patent eliminates the need for lubrication systems by replacing friction-based bearing mechanisms with elastic flexure-based pivot elements. This substitution removes the complexity associated with lubrication application, monitoring, and maintenance while maintaining smooth pivot motion through elastic deformation.
Solution Approach 2:
The flexure pivot system is self-lubricating by design, as it operates without friction through elastic flexing. The system requires no external lubrication services or maintenance, thereby reducing device complexity and improving ease of operation in terms of maintenance requirements.
3Ease of operation
If traditional bearing-based universal joints are used, then pivot capability is achieved, but wear and slop reduce measurement precision and positioning accuracy
Solution Approach 1:
The patent replaces bearing-based pivot mechanisms with flexure pivot elements that eliminate mechanical contact and associated wear. This substitution removes the source of slop and positioning errors, thereby improving measurement precision and angular position accuracy in high-precision applications such as steering mirrors and scan mirrors.
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 enables precise and durable two-axis pivot capability with reduced wear and maintenance costs, enhancing the reliability and accuracy of high-precision mechanisms by eliminating friction and the need for lubrication.
Implementation Method 1
Because angular motion is accomplished through flexing of elastic flexural elements, rather than contact surface displacement, flexural pivots operate without friction and thus without a need for lubrication.
Data Source
AI summary
A dual-axis flexure gimbal device, such as for a fast-steering mirror assembly, can comprise a flexure spring mass body comprising first and second body sections, a flexure diaphragm that interconnects the first and second body sections, and a central aperture formed through the first and second body sections and the flexure diaphragm. A flexure unit can be situated in the central aperture, and can comprise a plurality of slots defining a plurality of flexures. The flexure diaphragm is operable to bend about first and second rotational degrees of freedom, and the plurality of flexures of the flexure unit are operable to flex about respective first and second rotational degrees of freedom. The flexure unit can comprise a plurality of slots, each having a first slot portion and a second slot portion extending in different directions to define a respective flexure. A method of making the dual-axis flexure gimbal device is provided.