Helical Spring Vibration Attenuation via Integral Composite Mass Element
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Solution Overview
Problem
Existing vibration mode shifting and/or attenuation devices for vehicle suspensions, such as those using helical springs, often fail to effectively limit vibration disturbances at the turns of the springs, leading to noise generation, and require complex and costly implementations to achieve effective vibration mode shifting and/or attenuation.
Innovation Solution
A vibration mode shifting and/or attenuation device with a heavy body integral around a portion of the spring coils, where the heavy body is secured in a way that it cannot move along or pivot around the central axis of the turns, comprising a core made of a denser material and an outer casing of a less dense material, such as an elastomer, to achieve a localized increase in mass for vibration mode shifting and/or attenuation without significantly impacting the device's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heavy body is added to the spring to attenuate vibration modes, then vibration attenuation is improved, but device complexity increases
Solution Approach 1:
The heavy body is integrated directly onto the spring coil by molding it around a portion of the coils, merging two separate components (spring and heavy body) into a single integrated assembly. This eliminates the need for separate mounting hardware and complex attachment mechanisms, thereby reducing device complexity while maintaining vibration attenuation functionality
Solution Approach 2:
The heavy body is positioned nested around a portion of the spring coils, with the heavy body's inner diameter matching the outer diameter of the spring. This nesting arrangement allows the heavy body to be tightly coupled to the spring without requiring additional mounting structures, simplifying the overall device design while ensuring effective vibration attenuation
2Reliability
If adhesive is provided between spring ends and fittings to filter vibration, then vibration filtering at ends is improved, but harmful vibration modes between ends persist
Solution Approach 1:
Instead of applying adhesive uniformly at the spring ends only, the heavy body is positioned to wrap around a specific portion of the coils in the middle section of the spring. This local placement of mass creates targeted vibration attenuation at the critical mid-spring region where harmful vibration modes occur, while leaving the end regions unchanged for proper mounting and vibration filtering functions
3Weight of moving object
If heavy body is made entirely of dense material, then mass is increased for vibration attenuation, but manufacturing cost and complexity increase
Solution Approach 1:
The heavy body is constructed as a composite structure with an inner core made of dense material (such as metal) and an outer envelope made of elastomeric material. This composite construction provides the necessary mass for vibration attenuation through the dense core while the elastomeric envelope facilitates simpler manufacturing processes, including molding and attachment to the spring, thereby reducing overall manufacturing cost and complexity
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 effectively shifts or attenuates undesirable vibration modes by increasing the mass of the spring's coils, reducing noise and maintaining the device's operational efficiency and manufacturing simplicity, while ensuring the heavy body's compactness and balanced distribution of mass for improved dynamic behavior.
Implementation Method 1
The heavy body has a mass dependent on the vibration modes of the spring so as to achieve a shift and/or an attenuation of the undesirable vibration mode of the turns of the spring
Implementation Method 2
The heavy body comprises a core made from a first material and an envelope made from a second material, the second material being different from the first material
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The device (10) has a heavy body (16) connected around a portion (Sp) of coils (18) of a helicoid spring (12) between spring ends (22, 24) of the spring. The body is connected to the portion such that the body cannot move along the portion under the function of the device, and cannot swivel around an axis (Sa) of the portion. The body is provided a core made of one material, and an envelope made of another material e.g. polymer material such as elastomer. The body has a mass dependant on oscillatory modes of the spring to carry out a shift and/or an attenuation of one mode of the coils.