Dynamic Damper Inertia Ratios for Low-Speed Vibration Damping
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Solution Overview
Problem
Existing fluid transmission devices face limitations in improving vibration damping performance in the low rotation region due to constraints in increasing the inertia mass of the mass main body, leading to reduced damping capacity and resonance issues before engine rotation speed increases significantly after lock-up.
Innovation Solution
The starting device is configured with a damper mechanism that includes an input element, intermediate elements, and a dynamic damper with a mass body and vibration absorption elastic body, where the moment of inertia ratios and rotation speed ranges are optimized to shift the resonance point to a higher frequency side, expanding the damping range and improving vibration absorption at lower rotation speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inertia mass of the mass main body is increased to improve vibration damping performance in the low rotation region, then the damping capacity is improved, but the size of the mass main body must be increased which is limited by the space between the first and second elastic bodies, and resonance occurs before engine rotation speed increases much after lock-up
Solution Approach 1:
The patent changes the inertial parameter configuration by reducing the inertia mass of the additional mass body to be smaller than that of the mass main body (Iadd < Imain), and optimizing the ratio relationship between additional inertia mass and main inertia mass. This parameter optimization allows achieving improved vibration damping performance in the low rotation region without requiring a larger mass main body, thereby avoiding resonance issues before lock-up while maintaining effective damping capacity.
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 configuration enhances vibration damping performance in the low rotation region by shifting the resonance point to a higher rotation side, allowing effective damping of engine vibrations at lower speeds and improving the coupling between the engine and input element, resulting in better vibration absorption just after lock-up.
Implementation Method 1
a dynamic damper including a mass body and a vibration absorption elastic body arranged between the mass body and the intermediate element of the damper mechanism
Implementation Method 2
a vibration absorption elastic body arranged between the mass body and the intermediate element
Implementation Method 3
a first elastic body transmitting a torque between the input element and the intermediate element, a second elastic body transmitting the torque between the intermediate element and the output element
Data Source
AI summary
When “It” is defined as the moment of inertia of all elements included in a torque transmission path from a front cover 3 to a damper hub 7, “Im” is defined as the moment of inertia of a first intermediate member 12 coupled to a vibration absorption spring Spd of a dynamic damper 20, “Idd” is defined as the moment of inertia of a mass body of the dynamic damper 20, “A=Im/It”, “B=Idd/Im”, and “Netag” is defined as a rotation speed of an engine corresponding to a frequency of vibration to be damped by the dynamic damper, the starting device is configured so as to satisfy 0.04≤A≤0.10, 0.90≤B≤2.60 and 900 rpm≤Netag≤1400 rpm.