Shaped-Blade Flexural Pivot Assembly for Low-Power Rotation
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Solution Overview
Problem
Existing flexural pivots require excessive power to rotate and often result in decentering of mounts during movement, limiting their effectiveness in supporting movable structures like oscillating mirrors while maintaining strength and load capacity.
Innovation Solution
A flexural pivot design featuring blades with varying thickness along their length, forming a unitary structure from a single piece of material, which allows for controlled rotation and increased fatigue life without excessive stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stiffer flexure members are provided to increase the strength of the flexural pivot, then the load capacity is improved, but the power required to rotate increases unacceptably
Solution Approach 1:
The blade thickness is varied locally along its length, with the thickest section at the center and progressively thinner sections toward the ends. This local quality variation allows the blade to provide maximum strength where needed (at the center where loads are highest) while reducing stiffness and rotational resistance at the ends, thereby resolving the contradiction between load capacity and rotational power requirement
Solution Approach 2:
The geometric parameter of blade thickness is changed along the length of the blade, transitioning from a uniform thickness to a variable thickness profile. This parameter change optimizes the balance between structural strength and rotational flexibility, allowing the flexural pivot to support loads effectively while requiring acceptable power for rotation
2Strength
If the number of flexure members is increased to increase the strength of the flexural pivot, then the load capacity is improved, but the device complexity increases
Solution Approach 1:
Multiple blades are formed as a single integral structure from one piece of material, merging what would traditionally be separate components into one unified part. This combining approach maintains the load capacity benefits of having multiple blades while eliminating the complexity of assembling, aligning, and securing multiple separate flexure members
3Reliability
If non-symmetric blade shaping is used to optimize performance, then the flexibility and fatigue life are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The blade is divided into distinct thickness zones (center thickest section, intermediate sections, and end sections) with defined geometric relationships. This segmentation approach simplifies the manufacturing process by providing clear geometric guidelines for each zone while achieving the desired non-symmetric profile for optimized flexibility and fatigue performance
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
Enables rotation at lower power input and increased fatigue life while maintaining strength and load capacity, preventing decentering and reducing rotational stiffness, thus improving the overall performance of the flexural pivot.
Implementation Method 1
The flexure members or blades allow a limited degree of rotation or pivoting of one mount relative to the other while providing a degree of 'torsional-like' resistance to such movements. Rotation or a pivoting of one mount relative to another mount is achieved by a bending of the flexure members.
Data Source
AI summary
Flexural pivot structures and methods are provided. A flexural pivot as disclosed allows for rotation of a pivoted member relative to a base member about a central axis, while inhibiting or preventing movement of the pivoted member relative to the base member in any other direction. Base and pivoted sections of the flexural pivot structure are connected to one another by a set of resilient blades or flexural members. A thickness of the blades varies with the distance from the central axis. The components of the flexural pivot can comprise a monolithic structure that is formed from a single piece of material.