Bonded Vibration Isolator Structure for Lower Natural Frequency
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Solution Overview
Problem
Existing vibration isolators in high-end business aircraft suffer from loose elastomeric grommets that can be lost during installation, increase natural frequency due to vibration, and have a short lifespan due to friction, leading to maintenance and cost issues.
Innovation Solution
A vibration isolator design featuring a bonded resilient core within the housing and sleeve, with a tapered configuration that reduces natural frequency and extends the core's lifespan, utilizing retention tracks and members to secure bushings and prevent vibration-induced friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If elastomeric grommets are disposed loosely within the body of the vibration isolator, then the grommets can be easily installed, but they are subject to being accidentally lost during installation and increase the natural frequency due to independent vibration
Solution Approach 1:
The elastomeric grommet is nested within a retaining structure formed by the housing and bushing assembly. The housing includes an inwardly extending extension that creates a retention cavity, and the bushing fits within the housing to further secure the grommet, preventing it from being lost during installation while maintaining ease of installation.
2Ease of operation
If elastomeric grommets are disposed loosely within the body of the vibration isolator, then the installation is simplified, but the natural frequency of the vibration isolator increases due to independent vibration of the grommets
Solution Approach 1:
The grommet is nested within the housing and bushing structure, which constrains its movement and prevents independent vibration. This nesting arrangement simplifies installation while reducing the natural frequency by eliminating loose vibration of the grommet.
Solution Approach 2:
The housing and bushing are pre-configured with retention features (inwardly extending extensions and fitted interfaces) that automatically secure the grommet in place during installation. This preliminary structural preparation ensures the grommet is immediately constrained, preventing both loss and independent vibration without requiring additional installation steps.
3Reliability
If elastomeric grommets are used in the vibration isolator, then damping functionality is provided, but the grommets have a short lifespan due to friction between components under loads
Solution Approach 1:
The grommet is nested within a precisely fitted retaining structure formed by the housing extension and bushing. This nested arrangement eliminates relative movement and friction between the grommet and surrounding components under load, thereby extending the grommet's lifespan while maintaining its damping functionality.
Solution Approach 2:
The housing and bushing are pre-configured with retention features that securely hold the grommet in place before operational loads are applied. This preliminary securing prevents friction-induced wear during operation, extending the grommet's service life while preserving its damping capabilities.
4Reliability
If the resilient core is bonded to the housing and sleeve, then the natural frequency is decreased and lifespan is extended, but the manufacturing complexity increases
Solution Approach 1:
The bonding of the resilient core to the housing and sleeve is combined with the assembly process itself. The housing includes an inwardly extending extension that forms a bonding surface, and the bushing is fitted within the housing to provide additional bonding support. This integration of bonding and assembly simplifies manufacturing while achieving the desired natural frequency reduction and lifespan extension.
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 bonded resilient core vibration isolator achieves improved high-frequency performance, reduced natural frequency, and extended maintenance intervals by securely attaching the core to the housing and sleeve, minimizing vibration and maintenance needs.
Implementation Method 1
a resilient core positioned between and secured to a bottom surface of the housing and a top surface of a flange of the sleeve
Implementation Method 2
The resilient core conforms to a portion of an inner surface of the housing to form an upper surface
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A vibration isolator (2) includes a housing (4) having a top surface, an opposing bottom surface, and a hollow interior and an open- ended sleeve (18) having a hollow interior and an extending flange, the extending flange having a top surface and a bottom surface. A resilient core (14), having a hollow interior, is positioned between and fixedly coupled to the bottom surface of the housing (4) and the top surface of the flange of the sleeve (18). The resilient core (14) is disposed within a portion of the hollow interior of the open-ended sleeve (18). A first bushing (30) is disposed within the interior of the sleeve (18). The first bushing (30) has a flange including a bottom surface that overlays a top surface of the resilient core (14). A second bushing (44) is disposed within the first bushing (30).