Abstract
Recently, gear rattle noise is gradually becoming a nonignorable issue involving comfortableness in automotive transmission for a car. Generally, the rattle noise is influenced by nonlinear dynamic of multiple pairs of idler gears in the multistage gear transmission system. Optimization methods based on nonlinear rattle dynamic analysis are worthy of further study to control the noise. In this research, an equivalent rattle dynamic model of the idler gear is proposed, and the nonlinear rattle dynamic responses are solved based on the integral method. The effect laws of key factors on nonlinear dynamic performance are investigated by using a bifurcation diagram, spectrum map, and Poincaré map. Finally, the gear backlash, equivalent mass, and rotational speed are optimized based on Kriging surrogate model (KSM) and differential evolution (DE) algorithm by taking the minimization of the maximum rattle noise as the optimal object. It can be concluded that the rattle dynamics of the idler gear show rich nonlinear characteristics as the parameters change. The proposed method can not only reduce the sound pressure level of rattle noise but also provide a viable path and reference value for the low-noise design of the gear transmission system.
Highlights
The total rattle noise for the multistage gear transmission system is produced by the single pair of gears and it is derived from the superposition of several rattle noise sources with different sound levels in all pairs of idler gears, and some nonlinear factors between each pair of idler gears show coupling relationship
Even if the influence of nonlinear factors on the rattle motion of idler gears is clarified, the mechanism of the total rattle noise is affected by many factors, and it is necessary to work on the whole driveline design in the multistage gear transmission system [20,21,22]
In order to deal with the influence of multiple coupling parameters, Harris et al [23] established an impact dynamic model by using the elastic restorer between active gears and idler gears, in which the rattle threshold was verified, and the model can be applied for analysis of rattle noise in the transmission system
Summary
(1) e rattle e ects between gear teeth nish in a short moment, and the restitution coe cient is used to describe rattle action (2) e drag torque on the idler gear is constant when impact action is not occurred (3) e angular displacement of the active gear is simpli ed as harmonic excitation e equivalent dynamic model of a single pair of idler gear is established in Figure 2, in which Rb1 and Rb2 are the pitch radius of active gear and idler gear, respectively. (1) e rattle e ects between gear teeth nish in a short moment, and the restitution coe cient is used to describe rattle action (2) e drag torque on the idler gear is constant when impact action is not occurred (3) e angular displacement of the active gear is simpli ed as harmonic excitation e equivalent dynamic model of a single pair of idler gear is established, in which Rb1 and Rb2 are the pitch radius of active gear and idler gear, respectively. It can be seen from the above function that many factors may a ect impact intensity of idler gears, in addition to rotation speed, equivalent mass of idler gear, and gear backlash, and drag torque of the idler gear may in uence impact intensity between the active gears and idler gears.
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