zoro gear transmission

Gear transmissions such as bevel and planetary gears are widely used in a many kinds of machines and vehicles because of their reduced cost, power-to-weight ratio and high efficiency. In this context, the investigation of the dynamic behavior of gearboxes appears as an interesting step for machine design. In this context, the present paper investigates the dynamic behavior of gearboxes mounted in the Bucket Wheel Excavator which is used as continuous digging machine in large-scale open pit mining operations. The main gearbox driving the wheel excavator is composed of two stages. The first one is a bevel gear reducer and the second is a helical planetary gearbox (figure 1).

Bevel gear transmissions are used to transmit torque between non-parallel shafts. The modeling of the vibratory behavior of parallel axis geared rotor system was widely treated in literature (1)-(2), however few research works were dedicated to straight and spiral bevel gears dynamics. In (3), Yinong presented an 8 degrees of freedom nonlinear dynamic model of a spiral bevel gear pair which involved time-varying mesh stiffness, transmission error, backlash, and asymmetric mesh stiffness.

On the other hand, planetary gear sets consist of either spur or helical gears. Spur planetary gear sets can be commonly found in heavy machinery and off-highway gearboxes and transmissions, while the helical planetary gear sets are the norm for all automotive applications as in automatic transmissions and transfer cases. The planetary gear dynamic behavior was widely studied in literature (4)-(8). Most of the models employed two dimensional formulations, which can only consider spur gears. In (5), Lin recovered for this kind of models three types of modes: translational, rotational and planet modes. Moreover, helical planetary gears, which are shown to be quite different dynamically from spur gears (6)-(7), are generally preferred since they are quieter especially in automotive applications. In (8), Saada used finite elements method to compute the response of a three-dimensional helical planetary gear model.

From an experimental point of view, Bartelmus and Zimroz (9) classified gearbox into compound and complex gearboxes where it is possible to find both bevel and planetary gears and they determined their characteristic frequencies. In (10), Bartelmus used the same classifications to make a diagnostic feature.

This paper investigates a dynamic behaviour of a bevel gear transmission coupled to a single stage helical planetary gearbox mounted in a Bucket Wheel Excavator. A lumped parameters dynamic model is developed. All components are modeled as rigid bodies supported by flexible bearings. This model takes into account the different mesh stiffness functions in bevel and planetary parts of the gearbox and the different phasing between meshes. The simulation of the dynamic behavior is achieved in time domain by using an implicit Newmark’s time-step integration scheme. Based on this simulation, accelerations in the input and output rotating elements will be presented and discussed.