Tuned Resilient Bush Structure for Eigenmode Vibration Isolation
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Solution Overview
Problem
Existing vibration isolation bushes exhibit increased dynamic stiffness at specific eigenmodes, reducing vibrational isolation between components like an engine and chassis, particularly at frequencies associated with normal operation, leading to unwanted noise and vibration.
Innovation Solution
Incorporating a tuning element, such as an annular wall or wing, integrally formed with the resilient body of the bush, which reduces dynamic stiffness increases at eigenmodes by acting as a mass damper, effectively damping resonances across a predetermined operational vibration frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resilient body is used to isolate vibrations between components, then vibrational isolation is provided, but dynamic stiffness increases at eigenmodes reduce isolation effectiveness in certain frequency ranges
Solution Approach 1:
The patent modifies the physical parameters of the resilient body by adding a tuning element with specific geometric characteristics (annular shape, predetermined dimensions, specific material properties). This changes the dynamic characteristics of the resilient body to reduce eigenmode effects in the target frequency range, thereby maintaining consistent dynamic stiffness and effective vibration isolation across the operational frequency range.
2Speed
If the resilient body is designed for high frequency vibration isolation, then isolation is improved in that range, but eigenmodes still cause stiffness increases that reduce isolation
Solution Approach 1:
The patent applies a locally-specific tuning element to the resilient body that is optimized for particular frequency ranges. The annular tuning element has predetermined dimensions and material properties tailored to address eigenmode issues in specific high-frequency ranges, providing localized vibration control without compromising overall isolation performance across the operational frequency spectrum.
3Ease of manufacture
If conventional bush design is used, then manufacturing is simple, but vibration isolation is reduced at eigenmode frequencies
Solution Approach 1:
The patent combines the tuning element with the resilient body into a single integrated component. The tuning element can be integrally formed with the resilient body or bonded/attached to it, merging two functional elements (vibration isolation and eigenmode tuning) into one unified bush structure. This maintains manufacturing simplicity while significantly improving vibration isolation consistency across the operational frequency range.
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 solution ensures consistent vibrational isolation across the desired frequency range, reducing noise and vibration between interconnected components, particularly beneficial for electric vehicles where high-frequency vibrations are prevalent.
Implementation Method 1
The tuning element may act as a mass damper, and in particular may be tuned to reduce or eliminate the effect of eigenmodes of the resilient body within a predetermined frequency range
Implementation Method 2
effectively damping resonances across a predetermined operational vibration frequency range
Implementation Method 3
a resilient body, e.g. of rubber or other suitable elastomeric material
Implementation Method 4
resilient material, such as rubber
Data Source
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AI summary
A tuning element that can be integrally formed with a resilient body of a bush and configured to reduce dynamic stiffness increases associated with eigenmodes of the resilient body within a predetermined operational vibration frequency range. The tuning element may resemble an upstanding wall or wing on an outer surface of the resilient body. The resilient body may comprise a plurality of radial arms having axial passageways therebetween. The tuning element may bridge the passageways. A bush configured in this way may be particular suitable for use in scenario where the operational vibration frequency range comprises high frequency, such as an engine mount for an electric vehicle.