Nonlinear Analysis of Vibro-Impacts for Unloaded Gear Pairs With Various Excitations and System Parameters

Abstract

Torsional systems with clearance-type nonlinearities have inherent vibratory problems such as gear rattle. Such vibro-impacts generally occur on the unloaded gear pairs of a vehicle correlated with the firing excitation of an engine. This study investigates the gear rattle phenomena on unloaded gear pairs with different excitation conditions and various system parameters. First, a linear time-invariant system model with six degrees of freedom is constructed and then a numerical analysis is applied to the gear rattle motion. Smoothening factors for clutch stiffness and hysteresis are employed for the stability of numerical simulations. Second, the dynamic characteristics of vibro-impacts are studied by examining the fast Fourier transform (FFT) components of the gear mesh force in a high frequency range. The effects of various system parameters on the vibro-impacts are examined using a nonlinear system model. Finally, the vibro-impacts, in terms of “single-sided” and “double-sided” impacts, are identified in phase planes.

Effect of Various Excitation Conditions on Vibrational Energy in a Multi-Degree-of-Freedom Torsional System with Piecewise-Type Nonlinearities

“…Practical driveline components in various mechanical systems such as wind turbines and vehicles inherently contain various nonlinearities, such as multi-staged clutch dampers, gear backlashes, and drag torques [1][2][3]. Unloaded gears of typical gearboxes, excited by the dynamic torque from the engine fluctuation with even small mean loads, induce vibro-impacts due to gear backlash and multi-staged clutch damper.…”

“…Regarding this issue, theoretical background and simulation models can be directly connected to each other. In order to examine the nonlinear dynamic behaviors, a three DOF system model reduced from the original system shown in Figure 1 will be used [1][2][3]. Piecewise-type nonlinearities such as multi-staged clutch dampers will be employed to simulate the nonlinear dynamic behaviors in terms of relative motions in a simple driveline system model.…”

“…This study considers the asymmetrical piecewise-type nonlinearities based on the combined level of a driveline system [1][2][3]24]. The main objectives of this study are: (1) investigate the trends of nonlinear dynamic responses under various engine excitation conditions, which will lead to understanding of the relationship of nonlinear dynamic behaviors with different excitation levels by advancing prior studies [1][2][3]16,24].…”

“…The main objectives of this study are: (1) investigate the trends of nonlinear dynamic responses under various engine excitation conditions, which will lead to understanding of the relationship of nonlinear dynamic behaviors with different excitation levels by advancing prior studies [1][2][3]16,24]. (2) Poincaré map models for practical systems are suggested.…”

“…These sub-systems can be modeled simply with a lumped nonlinear model, as shown in Figure 1b. The method of reducing the original system into a reduced-DOF system has been investigated in prior studies [1][2][3] ) is the inertia of the transmission, which is lumped from the input, output shafts, speed gears, and differential; Ive (=8.08 × 10…”