Low Stiffness Torsional Spring-Damper Design for Vibration Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Low Stiffness Torsional Spring-Dampers are structurally and modally unstable in non-torsional directions, leading to potential buckling and failure under external or internal loads, and are expensive due to complex assembly and large elastomer volumes, with limited serviceability in the field.
Innovation Solution
A novel design featuring a central hub, tubular split-bushing, axisymmetric ring, grooved headed-pegs, and elastomeric O-rings or metallic extension springs, allowing only torsional loading, reducing elastomer volume, and enabling field serviceability without disassembly from the rotating shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Low Stiffness Torsional Spring-Damper is designed with large volumes of elastomer and elastomer to metal bonding to prevent structural and modal instability, then reliability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The elastomer is segmented into multiple discrete elements (cubes, spheres, or irregular shapes) rather than using a single large volume. These segmented elements are distributed between the inner and outer metallic sleeves, providing stability through collective behavior while reducing the complexity of any single elastomer component and eliminating the need for complex bonding procedures.
Solution Approach 2:
The patent employs simple, inexpensive elastomer geometries (cubes, spheres, or irregular shapes) that can be easily manufactured and replaced. These simple elastomer elements prioritize ease of manufacture and replacement over long-term durability of individual elements, allowing the system to maintain reliability through redundancy rather than through complex bonding of large elastomer volumes.
2Strength
If a Low Stiffness Torsional Spring-Damper is designed with large volumes of elastomer to prevent buckling and failure, then strength is improved, but manufacturing cost increases
Solution Approach 1:
The elastomer volume is divided into multiple small discrete elements that can be independently manufactured using simple processes. This segmentation allows each element to be produced at low cost while the collective arrangement of multiple elements provides the necessary strength and stability, avoiding the need for expensive bonding processes required for large single-piece elastomer components.
Solution Approach 2:
The patent changes the geometric parameters of the elastomer from large continuous volumes to small discrete elements with specific size ranges. This parameter change enables the use of simpler, less expensive manufacturing methods while maintaining the structural integrity and stability of the overall spring-damper system through the collective behavior of multiple elements.
3Reliability
If a Low Stiffness Torsional Spring-Damper is designed for vibration isolation and absorption, then vibration attenuation is improved, but the device becomes unserviceable in the field without disassembly
Solution Approach 1:
The elastomer is divided into multiple replaceable discrete elements that can be individually accessed and replaced. This segmentation allows maintenance personnel to service the device in the field by simply replacing worn elastomer elements without needing to disassemble the entire spring-damper unit or the rotating shaft, thereby maintaining vibration attenuation performance while improving ease of repair.
Solution Approach 2:
The patent designs the elastomer elements as disposable or replaceable components that can be discarded when worn and replaced with new elements. The metallic sleeves and other structural components are designed to be retained and reused, allowing the device to be serviced in the field by recovering the durable structural parts and replacing only the consumable elastomer elements.
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 design enhances structural and modal stability, reduces manufacturing costs, and allows for in-situ servicing of the device, maintaining performance and safety without elastomer disintegration.
Implementation Method 1
Elastomer springs are therefore preferred over metallic springs for constructing such devices because of their relatively low cost and weight, and the relatively higher coefficient of viscous damping present therein.
Implementation Method 2
Such rigid-body vibration is characterized by low frequency and large amplitude and is isolated from permeating the rest of the system by the introduction of a Low Stiffness Torsional Spring-Damper.
Implementation Method 3
Such flexible-body vibration is characterized by higher frequency and small amplitude and is attenuated from the vibrating shaft by absorbing it with a torsional spring-inertial system.
Data Source
AI summary
The disclosed invention is a novel method for constructing a Low Stiffness Torsional Spring-Damper that simultaneously yields the following advantages over conventional designs: (1) the elastomer is not mold-bonded to the two metallic extremities; (2) the amount of elastomer is relatively smaller compared to conventionally constructed devices; (3) the device only allows the torsional direction to be spring loaded; (4) there is some damping inherently present in the system; (5) the device does not disintegrate on failure of the elastomeric element; and (6) the device is serviceable in the field without disengaging from the rotating shaft. Such a Low Stiffness Torsional Spring-Damper when used in a Torsional Vibration Isolator or a Torsional Vibration Damper would reduce its cost while improving its structural and modal integrity and enabling its serviceability in the field.