Propshaft Damper with Helical Friction and Foam for Vibration Attenuation
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Solution Overview
Problem
Existing propshaft assemblies are inadequate in effectively attenuating shell mode vibration, which contributes to noise in vehicles, and often require additional mass or changes in propshaft geometry, limiting their effectiveness in reducing overall noise levels.
Innovation Solution
A propshaft assembly featuring a tubular member with a damper system comprising multiple damping devices, including a core with a helically wrapped damping member, a foam damping device with longitudinally extending grooves, and another core with a helically wrapped damping member, positioned between the end connections to engage the interior surface of the tubular member, effectively attenuating shell, torsion, and bending mode vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If weights or liners are added to attenuate vibrations, then vibration attenuation is improved, but the propshaft assembly becomes more complex and requires changes in mounting hardware or geometry
Solution Approach 1:
The damper is nested within the hollow propshaft tube, with the damping core positioned inside the propshaft's hollow interior. This nesting approach allows the damper to be integrated into the existing propshaft structure without adding external components or requiring changes to mounting hardware, thereby improving vibration attenuation while minimizing increases in assembly complexity
Solution Approach 2:
The damping core is positioned at specific locations within the propshaft where vibrations are most problematic. By concentrating damping material only where needed rather than uniformly throughout the entire propshaft, the solution provides effective vibration attenuation while minimizing the overall mass and complexity additions to the assembly
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 proposed solution significantly reduces noise by effectively damping shell mode vibrations and potentially other vibration modes, enhancing the overall sound quality of vehicles without the need for significant changes in propshaft geometry or mass addition, thereby meeting stringent consumer expectations for reduced noise levels.
Implementation Method 1
The damping member extends helically about the core and frictionally engages the interior circumferential surface
Implementation Method 2
The second damping device is formed of foam and is positioned in the tubular member between the first and third damping devices
Implementation Method 3
the vibration attenuation means deforms as vibration energy is transmitted through it so that the vibration attenuation means absorbs (and thereby attenuates) the vibration energy
Data Source
AI summary
A propshaft assembly that includes a tubular member, first and second end connections coupled to opposite ends of the tubular member and a damper that is received in the tubular member and positioned between the first and second end connections. The tubular member has a wall member that defines an interior circumferential surface. The damper has a first damping device, a second damping device and a third damping device. The first damping device has a first core and a first damping member that is fixed to the first core. The first damping member extends helically about the first core and engages the interior circumferential surface. The second damping device is formed of foam and is positioned in the tubular member between the first and third damping devices. The second damping device engages the interior circumferential surface. The third damping device has a second core and a second damping member that is fixed to the second core. The second damping member extends helically about the second core and engages the interior circumferential surface.