Gear impacts and idle gear noise: Experimental study and non-linear dynamic model

Abstract

International audienceThis paper develops an experimental and numerical study of dynamic phenomena involving gear impacts with one loose gear (non-engaged gear pair) inside an automotive gearbox. A dedicated test bench was designed for this study. Signal processing tools, based on the Order Tracking Method, were specially developed in order to clarify the underlying phenomena. A particular attention was paid to the relationship between the drive shaft excitation and the energy and nature of impacts. A topological model of contact is being proposed, based on a geometric description of solids in contact. The contact between gear meshes is defined using a Single Degree of Freedom, non-linear, elastic and dissipative model. The chosen parameters of the model are not updated from measurements, but from the knowledge of the gear topology and tolerance class. Simulations, compared with experimental results, confirm the accuracy of the model proposed. Both model and experiments show, for particular excitation conditions, the emergence of repeated impacts on one side of the gear mesh

Study on the noise and vibration of engine block coupled with the rotating crankshaft and gear train (Effect of the torsional vibration of crankshaft)

“…Therefore, gear train shaft is connected to the engine block by the radial bearings and one thrust bearing. When the steady torque is large enough not to cause separation of gear tooth, stiffness of meshing point changes with the torque and contact point of the gear tooth (Dion, et al, 2009). But in the case of idling operation discussed in this paper, separation and impact of gear tooth are generated by the rotational fluctuation of crankshaft and impulsive torque due to fuel injection.…”

Minimal modeling methodology to characterize non-linear damping in an electromechanical system

“…In practice, the damping c in Eq. (2) is often non-linear and can include dynamics of both static and dynamic friction and gear backlash [32,26,5]. The approach presented in this paper is to treat the damping c initially as time-varying then relating it to measured quantities like velocity and displacement.…”

“…(62) with c = c(t) the piecewise constant approximation defined by Eqs. (5) and (6) with n = 6. This analytical solution is defined:…”

“…The usual approach to capturing this phenomena is to have a pre-assumed non-linear representation, for example, the Bingham viscoplastic model, assumes that the force of the damper is a given non-linear function of the damper velocity [26], and the Bouc-Wen model includes a model describing hysteric behavior of the damper [30]. There are also several models of gear backlash [15,5]. Thus, the concept is to start with complex model structures first, and then fit it to the data.…”

Non-intrusive rattle noise detection in non-stationary conditions by an angle/time cyclostationary approach

“…The experimental analysis of rattle noise requires test benches able to reproduce engine acyclism by means of a universal joint for example [9]. Many studies are focused on idle gear noise (gearbox on neutral) and use electro-dynamic translation exciters [10,11]. Kadmiri et al [6] exploit a dedicated test bench replicating excitations from an automotive powertrain.…”