Planetary Torsional Vibration Damper for Low-Speed Engine Resonance
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Solution Overview
Problem
Existing torsional vibration dampers require a large number of parts, leading to high manufacturing costs and limited vibration damping performance, especially in low-speed engine ranges.
Innovation Solution
A torsional vibration damper with a planetary unit that includes a first rotary element, a second rotary element, and a plurality of planetary elements interposed between them, featuring an elastic member and a spring holder to increase the oscillation range of the planetary elements, allowing for enhanced vibration damping without increasing the size of the damper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first elastic body and the second elastic body are connected in series to allow the spring damper to be oscillated widely by the engine torque, then the antiresonance point is lowered and vibration damping performance is enhanced within a low speed range, but a large number of parts are required and manufacturing cost increases
Solution Approach 1:
The patent merges the functions of the first elastic body and second elastic body into a single elastic member that provides both the series connection effect for wide oscillation and the damping function. This consolidation reduces the number of parts while maintaining the vibration damping performance in the low speed range.
Solution Approach 2:
The single elastic member is designed to perform multiple functions: it acts as both the series-connected elastic bodies for wide oscillation range and provides the necessary damping characteristics. This multi-functional design eliminates the need for separate intermediate members and multiple elastic bodies.
2Length of moving object
If the first elastic body and the second elastic body as well as the intermediate member are interposed between the drive member and the driven member, then the spring damper can be oscillated widely, but the manufacturing cost may be rather high
Solution Approach 1:
The patent combines multiple components (first elastic body, second elastic body, and intermediate member) into a single integrated elastic member structure. This merging maintains the required oscillation range while significantly simplifying manufacturing processes and reducing costs.
Solution Approach 2:
The patent extracts the essential function of wide oscillation from the complex multi-component system and implements it through a simplified single elastic member design, removing unnecessary intermediate components that increase manufacturing complexity.
3Reliability
If the oscillation range of the planetary element is increased in the drive direction, then the resonance point shifts to the low-speed side and vibration damping is improved, but the damper size may increase
Solution Approach 1:
The patent employs asymmetric design in the elastic member configuration, where the first movable range (in drive direction) is made wider than the second movable range (in counter direction). This asymmetric oscillation range adjustment shifts the resonance point to the low-speed side without requiring proportional increases in all dimensions of the damper.
Solution Approach 2:
The patent applies local quality changes by concentrating the oscillation range increase specifically in the drive direction where it is most needed for vibration damping, rather than uniformly increasing all dimensions. This localized adjustment improves damping performance while minimizing overall size increase.
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 shifts the resonance point to the low-speed side, improving torsional vibration damping in the low-speed range of the engine without increasing the damper's size or manufacturing costs, by increasing the oscillation range and reducing the spring constant of the elastic member.
Implementation Method 1
an elastic member that is interposed between the input element and the output element to be deformed elastically by a torsional torque of the engine causing a relative rotation between the input element and the output element
Implementation Method 2
The inertia element is rotated by the torque of the engine and oscillated by a pulsation of the torque of the engine
Implementation Method 3
An inertia torque of the ring gear thus oscillated acts as a vibration suppressing torque to damp pulsation of output torque from the planetary gear unit
Data Source
AI summary
A torsional vibration damper that damps torsional vibration effectively in a low-speed range. In the torsional vibration damper, a spring holder is formed by apertures of an input element and an output element, and an elastic member is held in the spring holder. A first moveable range of a planetary element extending from an initial position in a drive direction is wider than a second movable range of the planetary element extending from the initial position in a counter direction.