Tuned Damper for Damped Propshaft Assembly
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Solution Overview
Problem
Existing methods for damping propshaft vibrations in automotive drivelines are inadequate in effectively attenuating shell mode, bending mode, and torsion mode vibrations, as they either add excessive mass, require changes in propshaft geometry, or are ineffective across multiple vibration modes.
Innovation Solution
A method involving a hollow shaft with a tuned damper comprising a liner and a damping member, where the mass and stiffness of the liner are tuned to attenuate specific vibration modes, and the damping member provides additional broadband damping across multiple frequencies, effectively reducing shell, bending, and torsion mode vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If weights or liners are added to attenuate vibrations, then vibration attenuation is improved, but the mass of the propshaft assembly increases
Solution Approach 1:
The patent applies parameter changes by precisely tuning the mass and stiffness parameters of the liner to specific values that enable effective vibration attenuation at target frequencies. By optimizing these physical parameters, the system achieves high damping performance without requiring excessive mass, thereby resolving the contradiction between vibration attenuation and weight increase.
Solution Approach 2:
The patent employs composite materials by combining the liner (with tuned mass and stiffness properties) with the propshaft structure. This composite approach allows the liner to provide targeted vibration attenuation while maintaining overall system efficiency, achieving effective damping without the need for heavy solid weights.
2Object-affected harmful factors
If discrete weights are used to attenuate bending mode vibration, then bending mode vibration is reduced, but the technique is ineffective against shell mode and torsion mode vibration
Solution Approach 1:
The patent implements universality by designing the liner with specific mass and stiffness characteristics that enable it to attenuate multiple vibration modes simultaneously - including bending mode, shell mode, and torsion mode vibration. This multi-functional design replaces the need for different damping solutions for each vibration mode, achieving broad-spectrum vibration attenuation with a single component.
Solution Approach 2:
The patent uses parameter changes by tuning the liner's mass and stiffness to specific values that create effective attenuation across multiple vibration modes. By carefully selecting these parameters, the liner becomes a universal damping solution that addresses bending, shell, and torsion modes, rather than being limited to a single mode as with traditional discrete weights.
3Object-affected harmful factors
If the propshaft geometry or wall thickness is changed to accommodate vibration damping weights, then vibration attenuation is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies segmentation by separating the vibration damping function from the propshaft structural geometry. Instead of modifying the propshaft itself, the damping function is isolated in a separate liner component with tuned mass and stiffness properties. This segmentation allows the propshaft to maintain its original geometry for manufacturing efficiency while the liner provides the required vibration attenuation.
Solution Approach 2:
The patent introduces the liner as an intermediary component that mediates between the propshaft structure and the vibration attenuation requirement. The liner acts as a separate element that can be tuned independently to provide damping without requiring modifications to the propshaft geometry, thereby simplifying manufacturing while achieving effective vibration control.
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 effectively attenuates multiple vibration modes within a propshaft assembly, reducing noise and improving sound quality in vehicles by tuning the damper to specific frequencies, thereby enhancing the overall damping performance without significant changes to the propshaft's geometry or mass.
Implementation Method 1
tuning a mass and a stiffness of at least one liner to form an intermediate damper, the intermediate damper being configured to attenuate at least one of a bending mode vibration and a torsion mode vibration
Implementation Method 2
The damping member is coupled to the liner and is configured to primarily attenuate shell mode vibration in the hollow shaft at one or more desired frequencies
Implementation Method 3
tuning a mass and a stiffness of at least one liner to form an intermediate damper, the intermediate damper being configured to attenuate at least one of a bending mode vibration and a torsion mode vibration that occurs at a first predetermined frequency
Data Source
AI summary
A damped propshaft assembly with a hollow shaft and a tuned damper, which is received in the hollow shaft and includes a liner and a damping member. The liner's mass and stiffness are tuned to attenuate one or more of a bending mode vibration and a torsion mode vibration that occurs at a first predetermined frequency. The liner is not configured to substantially damp shell mode vibration that occurs at a frequency that is not equal to the first predetermined frequency. The damping member is coupled to the liner and is configured to primarily attenuate shell mode vibration in the hollow shaft at one or more desired frequencies. The tuned damper attenuates the at least one of the bending moment vibration and the torsion mode vibration at the first predetermined frequency and also attenuates shell mode vibration. A method for forming a damped propshaft assembly is also provided.