Piston Assembly Vibration Damping for Pneumatic Actuators
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Solution Overview
Problem
Pneumatically actuated butterfly valves face issues with wear due to bearing wear and torsional mode excitation in high vibration environments, leading to excessive piston ring and crank mechanism wear.
Innovation Solution
The piston assembly incorporates detachable first and second covers affixed to the piston rod with high-strength fasteners, increasing the natural frequency of the piston assembly beyond the operating environment's torsional modes, thereby reducing torsional strain and wear through enhanced stiffness and damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a link with bearings at each end is used to connect the piston and crank arm, then the connection between piston and crank is provided, but bearing wear issues occur
Solution Approach 1:
The patent removes the link and bearings from the system entirely. Instead of using a separate link with bearings to connect the piston to the crank arm, the piston rod is directly connected to the crank arm, eliminating the bearing components that cause wear problems.
Solution Approach 2:
The patent merges the piston rod and crank arm connection into a single integrated structure. The piston rod directly engages with the crank arm without an intermediate link, combining what were previously separate components into a unified connection system.
2Stability of the object's composition
If the piston has rotational inertia and the link provides torsional stiffness, then the torsional stability is maintained, but excessive piston ring wear occurs in high vibration environments
Solution Approach 1:
The patent removes the link component that provided torsional stiffness, replacing it with a different structural approach where the piston rod itself and its direct connection to the crank arm provide the necessary stiffness without exciting torsional modes.
Solution Approach 2:
The patent changes the structural parameters of the piston assembly by eliminating the link and directly connecting the piston rod to the crank arm. This alters the torsional stiffness characteristics and natural frequencies of the system, moving them away from excitation frequencies in high vibration environments.
3Reliability
If detachable covers are added to the piston rod, then the natural frequency is increased and wear is reduced, but the device complexity increases
Solution Approach 1:
The patent divides the piston rod into multiple segments by adding detachable covers that can be removed and reattached. This segmentation allows the piston rod to be serviced, inspected, or replaced in sections, reducing overall wear and extending component life.
Solution Approach 2:
The patent makes the piston rod structure dynamic by introducing detachable covers that can be added or removed based on operational needs. This allows the structural characteristics of the piston rod to be adjusted or modified without replacing the entire component.
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 design significantly reduces wear and increases the natural frequency of the piston assembly, minimizing damage and extending the lifespan of components in high vibration environments.
Implementation Method 1
increasing the natural frequency of the piston assembly beyond the operating environment's torsional modes
Implementation Method 2
reducing torsional strain and wear through enhanced stiffness and damping
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A piston assembly (10; 52) includes a piston (12; 56) with a first cap (20; 64) disposed on a first end (22; 70) of the piston (12; 56) and a second cap (24; 66) disposed on a second end (26; 72) of the piston (12; 56). A piston cross-member (14; 58) is in between the first cap (20; 64) and the second cap (24; 66). A first cover (16; 60) is affixed to a first side of the piston cross-member (14; 58). A second cover (18; 62) is affixed to a second side of the piston cross-member (14; 58). The second side of the piston cross-member (14; 58) is opposite the first side of the piston cross-member (14; 58).