This article analyses vibration transmission on agricultural tractors with the excitation from the road to the driver’s seat. A multi-body model of agricultural tractors created in Adams is presented. The main parts for the investigation of vibration transmission are the tractor body, where the only suspension elements are tyres, the tractor cabin, spring-dampers suspended at the rear and bushings at the front, and the driver seat with its pneumatic spring. A series of measurements were performed, and the model was validated using vertical acceleration values on the tractor body at four different locations. The FTire model (physical FEM-based model) was chosen to describe the behaviour of tyres. The model was created using measured tyre characteristics. Measured characteristics of spring-dampers and front cabin bushings were also implemented. For comfort investigation, ride simulations on ISO 5008 rough roads were performed. The transmission of vibrations in ride simulations was examined. A modal analysis of the linearised model was performed to confirm assumptions of the contribution of suspension elements to overall vibration levels. Finally, three case studies were conducted to better understand the model’s vibration transmission properties.

Transmission error (TE) is a significant parameter related to gears vibration widely investigated by many authors using different approaches. However, in previous studies, spur and helical gears were mainly examined. There is a lack of studies addressed to double helical and herringbone gears and a comparison among several types of gearing with parallel axes. In this paper, spur, helical, double helical, and herringbone gears are analyzed in terms of static transmission error (STE), contact pressure and tooth root stress. Static contact analyses were conducted using the finite element method (FEM) which is often considered a tool for validating other methods and approaches. Moreover, three variants of boundary conditions of each gear type are introduced, including flexible shafts and the effect of a tip relief modification at sole gears, without shafts, was analyzed. In addition, a concept of a compact test rig intended for STE measurements at low loads was presented. The results have shown, among other things, significant influence of the shaft stiffness and boundary conditions on meshing characteristics.