Segmented Torsional Vibration Damper for Stable Natural Frequency
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Solution Overview
Problem
Torsional vibration dampers (TVDs) face design and operational challenges due to the rubber layer's multiple functions, leading to compromised performance, including heat dissipation issues, aging, and high shear stresses, which affect the damper's ability to control torsional vibrations effectively.
Innovation Solution
A torsional vibration damper design featuring a hub portion and an outer ring with radial connectors and spacers that are elastically deformable, where the spacers dissipate energy via heat conversion and have a distinct spring rate configuration to maintain a constant natural frequency, reducing the impact of temperature and aging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber layer is used to provide multiple functions (damping, heat dissipation, flexibility), then the damper can control torsional vibrations, but the performance is compromised due to heat dissipation issues, aging, and high shear stresses
Solution Approach 1:
The rubber layer is segmented into multiple discrete rubber elements arranged radially between the inner and outer rings. This segmentation reduces the shear stress on each individual rubber element compared to a single continuous rubber layer, while maintaining the overall damping function. The segmented structure also improves heat dissipation by creating gaps between rubber elements that allow heat to escape.
Solution Approach 2:
Metallic radial connectors are introduced as intermediary elements between the inner and outer rings. These connectors bear the primary mechanical load and transmit forces, reducing the shear stress burden on the rubber elements. The rubber elements focus on providing damping and flexibility, while the metallic connectors handle structural load transmission.
2Reliability
If a rubber layer is used to provide multiple functions, then the damper can control torsional vibrations, but the rubber layer experiences high shear stresses that reduce its operational life
Solution Approach 1:
The rubber layer is divided into multiple discrete rubber elements, which distributes the shear stress across more individual components. This reduces the stress concentration on any single rubber element, slowing down degradation and extending operational life while maintaining the collective damping performance of all rubber elements together.
Solution Approach 2:
The metallic radial connectors serve as intermediaries that carry the primary mechanical loads, shielding the rubber elements from excessive shear stresses. This protective arrangement allows the rubber elements to function primarily for damping without being overloaded, thereby extending their service life.
3Reliability
If the rubber layer is made softer to improve damping, then torsional vibration control is enhanced, but the natural frequency changes due to temperature and aging effects
Solution Approach 1:
The damper uses a composite structure combining metallic radial connectors with rubber elements. The metallic portion provides stable, temperature-insensitive structural support and load transmission, while the rubber elements provide damping. This composite approach allows the system to maintain a stable natural frequency determined by the rigid metallic components while still achieving effective vibration control through the rubber's damping properties.
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 design enhances the damper's ability to maintain consistent performance by minimizing the effects of temperature and aging on the natural frequency, reducing resonance, and extending the damper's operational life by effectively dissipating heat and reducing shear stresses.
Implementation Method 1
the spacers are non-metallic and dissipate energy from deformation via conversion to heat
Implementation Method 2
the radial connectors are elastically deformable to permit relative circumferential movement about the axis between the outer ring and the hub portion and which urge the outer ring and the hub portion back towards a neutral position there during
Data Source
AI summary
In an aspect, a torsional vibration damper is provided, comprising a hub portion that mounts to a crankshaft, an outer ring that includes an inertial mass, a plurality of radial connectors that are elastically deformable and a plurality of spacers that extend circumferentially between the radial connectors and which are elastically deformable by the radial connectors during flexure thereof. The spacers are non-metallic and dissipate energy from deformation via conversion to heat. The plurality of radial connectors have a circumferential spring rate K1a in bending in a circumferential direction about the axis, and have an axial spring rate K1b in bending in an axial direction, wherein K1b is at least 10 times as large as K1a. The plurality of spacers have a circumferential spring rate Kra in the circumferential direction, and an axial spring rate Krb in bending in the axial direction, wherein Kra is less than 1% of K1a.