Torsional Oscillation Damper Sizing for Vehicle Powertrains
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Solution Overview
Problem
Existing torsional oscillation dampers in vehicle powertrains fail to optimally filter torsional oscillations due to significant vibrations on the pendulum-type damping device's support, leading to saturation of pendular bodies and suboptimal filtering performance.
Innovation Solution
A method for dimensioning the second damping stage of a torsional oscillation damper, where the stiffness of the second elastic return members is determined based on the moment of inertia of the downstream system, pendulum-type damping device, and gearbox input shaft, ensuring the support of the pendulum-type damping device acts as a node for torsional oscillations without affecting the moment of inertia or stiffness of other components, thereby canceling vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first damping stage and pendulum-type device are appropriately sized to filter torsional oscillations, then the filtering performance is improved, but the support of the pendulum-type device experiences significant vibrations causing saturation and suboptimal performance
Solution Approach 1:
The invention changes the stiffness parameter of the second elastic restoring elements (K2) to create a specific dynamic condition where the support becomes a node for the torsional oscillation wave. By adjusting K2 relative to K1 and the moments of inertia, the system transforms the support from a vibrating component to a stationary node, eliminating harmful vibrations while preserving filtering performance
Solution Approach 2:
The second damping stage acts as an intermediary element between the first damping stage and the gearbox. It introduces a new stiffness parameter (K2) that mediates the torsional oscillations, creating a node at the pendulum support and preventing vibration transmission to the gearbox while maintaining the overall filtering function
2Reliability
If the stiffness of the second elastic return members is adjusted to cancel vibrations, then the filtering performance is enhanced, but the device complexity increases due to additional dimensioning parameters
Solution Approach 1:
The invention introduces a specific relationship between parameters (K2, K1, I1, I2, Itransmission) that creates a node condition. While this adds a dimensioning step, it provides a clear mathematical relationship that simplifies the design process compared to trial-and-error methods, and the additional parameter K2 offers fine-tuning capability for optimal performance
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 approach effectively cancels vibrations on the pendulum-type damping device's support, enhancing the filtering performance of torsional oscillations while adhering to the constraints imposed by vehicle manufacturers.
Implementation Method 1
a second damping stage, comprising second elastic return elements
Implementation Method 2
reduce torsional oscillations that propagate through the powertrain
Implementation Method 3
a pendulum-type damping device, comprising a support and pendulum bodies movable relative to this support
Implementation Method 4
the value of the moment of inertia of the pendulum-type damping device
Data Source
Figure 1
AI summary
The invention relates to a method for sizing the second damping stage of a torsional oscillation damper of a vehicle power train (1), said unit including: a system upstream from the torsional oscillation damper; a system downstream from the torsional oscillation damper; and the torsional oscillation damper, including: a first damping stage, including first resilient return members; the second damping stage, including second resilient return members; and a pendulum-type damping device, including a mounting (4) and pendulum bodies (3) movable relative to said mounting (4). Said method includes, given: the value of the moment of inertia (I_transmission) of the downstream system; the value of the moment of inertia of the pendulum-type damping device; the value of the stiffness (K1) of the single resilient return member modelling the first resilient return members; and the value of the stiffness (Kgis) of the input shaft of the gearbox (5), determining the value of the stiffness (K2) of the single resilient return member by modelling the second resilient return members so that the mounting (4) of the pendulum-type damping device is a node for the wave propagating in the power train (1) due to a cyclic irregularity of the drive engine.