Fluid-Coupled Torsional Vibration Damper With Stable Transmission Ratio
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Solution Overview
Problem
Existing torsional vibration damping arrangements with fluid transmission coupling arrangements face issues with centrifugal forces causing changes in transmission ratio, leading to suboptimal vibration damping behavior, especially at varying speeds.
Innovation Solution
A torsional vibration damping arrangement with a fluid transmission coupling design featuring a pair of cylinders arranged symmetrically or on the same side, utilizing a common pressure accumulator and check valves to compensate for pressure differences and maintain a stable transmission ratio, thereby avoiding static changes in the transmission ratio and enhancing vibration damping performance across different speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fluid transmission arrangement is used as the coupling arrangement, then the structure is simplified and the device is more compact, but centrifugal forces cause changes in transmission ratio leading to suboptimal vibration damping behavior
Solution Approach 1:
The patent applies asymmetry by arranging the first and second pairs of cylinders symmetrically with respect to a virtual plane, creating a balanced configuration that compensates for centrifugal force effects. This symmetrical arrangement ensures that pressure differences arising under centrifugal force in respective pairs of cylinders compensate each other, maintaining a stable transmission ratio across varying speeds.
2Stability of the object's composition
If the cylinders are arranged symmetrically on a virtual plane, then pressure differences are compensated and transmission ratio stability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the functionality of multiple cylinders by arranging them in pairs that work together. The first and second pairs of cylinders are connected such that they share common pressure accumulators and check valves, allowing them to compensate for each other's pressure differences. This merging approach achieves transmission ratio stability while avoiding the need for completely independent control systems for each cylinder.
3Device complexity
If a common pressure accumulator is used, then the device complexity is reduced and space is saved, but pressure compensation capability may be insufficient
Solution Approach 1:
The patent segments the pressure accumulation system by providing separate common pressure accumulators for different cylinder pairs rather than using a single universal accumulator. This segmentation allows each pair of cylinders to independently compensate their own pressure differences while sharing resources within their pair, balancing complexity and compensation capability.
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 cancels out torsional vibrations by phase-shifting and superimposing torque components, resulting in a torque transmitted to the output area with minimal vibration components, maintaining consistent transmission ratio and average engine torque across varying engine speeds.
Implementation Method 1
the fluid transmission arrangement having a first pair of cylinders and a second pair of cylinders
Implementation Method 2
there are problems caused by centrifugal forces, which result in a change in transmission ratio due to the centrifugal force acting on the active medium or hydraulic fluid
Implementation Method 3
pressure differences arising under speed / centrifugal force in the respective pair of cylinders can be compensated for and thus a static change in transmission ratio is avoided
Data Source
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AI summary
The invention relates to a torsional vibration damper assembly for the powertrain of a vehicle, comprising an input region to be rotated about a rotational axis (A) and an output region, wherein a first torque transmission path, a second torque transmission path parallel thereto, and a clutch assembly are provided between the input region and the output region. A phase shift assembly is provided in the first torque transmission path, and the clutch assembly is designed as a fluid transmission assembly. The fluid transmission assembly comprises a first cylinder pair and a second cylinder pair, said first cylinder pair being designed to be reciprocal to the second cylinder pair.