Closed-Cell Compliant Universal Joint for Buckling-Resistant Rotation
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Solution Overview
Problem
Existing universal joints face challenges in maintaining support stiffness during rotation and preventing buckling under compressive forces, while also dealing with the trade-off between axial and rotational stiffness, and limited directional movement control.
Innovation Solution
A compliant closed cell universal joint that transforms compressive forces into tensile stress within an elastic enclosure, using a hollow elastic body with a body deformation restriction member to prevent movement in selected directions, and employing an incompressible fluid to maintain stiffness and prevent buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If solid leaf flexures are used to create a compliant joint, then mobility is gained through elastic deformation, but axial stiffness becomes high while rotation stiffness becomes low
Solution Approach 1:
The patent introduces a pneumatic or hydraulic actuation system within the compliant joint structure. Fluid pressure is applied to controlled chambers to generate rotational motion and maintain stiffness, overcoming the limitation of passive elastic deformation alone. This allows the joint to achieve both mobility through compliance and sufficient rotational stiffness through fluid pressure support.
Solution Approach 2:
The patent employs adjustable fluid pressure as a controllable parameter to dynamically change the stiffness characteristics of the joint. By varying the pressure in the pneumatic or hydraulic system, the joint can adapt its rotational stiffness while maintaining mobility, resolving the trade-off between axial and rotational stiffness.
2Ease of operation
If compliant joints are designed to allow rotation, then mobility is improved, but support stiffness during rotation decreases
Solution Approach 1:
The pneumatic or hydraulic system provides active support stiffness during rotation by maintaining fluid pressure in controlled chambers. This pressure support compensates for the inherent loss of stiffness that occurs during rotational movement in compliant structures, allowing the joint to maintain both mobility and support stiffness simultaneously.
3Adaptability or versatility
If compliant joints are used to enable relative movement, then mobility is achieved, but buckling risk increases under compressive forces
Solution Approach 1:
The pneumatic or hydraulic system provides internal pressure support that actively prevents buckling under compressive forces. The fluid pressure creates an outward force that counteracts compressive loads, stabilizing the compliant structure during relative movement and preventing buckling failures.
Solution Approach 2:
The patent incorporates pre pressurized chambers or structural features that provide beforehand cushioning against compressive forces. This preventive measure ensures that the compliant joint maintains its structural integrity and resists buckling before compressive loads are applied during operation.
4Ease of operation
If universal joints are designed for rotational freedom, then mobility is improved, but control over directional movement is reduced
Solution Approach 1:
The pneumatic or hydraulic system enables independent control of movement in different directions through separate controlled chambers. By selectively applying pressure to specific chambers, the joint can control rotational movement while maintaining overall rotational freedom, achieving both mobility and directional control.
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
This solution ensures consistent support stiffness during rotation without risk of buckling and allows for precise control of movement, with analytical models confirming optimal stiffness performance by adjusting the joint's length and thickness.
Implementation Method 1
the compressive force on the joint is transformed through compression and deformation of the media inside the closed cell to a tensile stress in the elastic enclosure
Implementation Method 2
A compliant joint gains at least some of its mobility from the deflection of flexible members rather than from movable joints only. A compliant joint uses elastic deformation of flexible elements to generate motion.
Implementation Method 3
a body deformation restriction member attached to the wall and/or incorporated into the wall, for providing shear stiffness in a plane perpendicular to the at least one central axis
Data Source
AI summary
The present invention is in the field of mechanical engineering, and in particular of an engineering element for maintaining effective functioning of a machine or installation, such as for a piston pump. The present invention relates to a universal joint, such as for said piston pump, a use of said universal joint, and a product comprising said universal joint.