Reduction of rattle noise of a direct engine-PTO driveline of agricultural tractors: Part II. Causes of PTO rattle noise.

摘要

To investigate the causes of the power takeoff (PTO) rattle noise of a direct engine-PTO driveline, a 10-degree of freedom non-linear mathematical model of the driveline was developed and verified experimentally. The model was used to simulate the dynamic characteristics of the driveline motions and the effects of driveline parameters on the PTO rattle noise under the condition that generated the loudest PTO rattle noise. The results of the simulation identified that the PTO rattle noise was caused by collisions between the driving and driven gears in the PTO gearbox due to their velocity variations induced by the torque fluctuations from the engine. It was also found that the PTO rattle noise decreased as the drag torque and the mass moment of inertia of the engine flywheel increased. Smaller backlash and mass moment of inertia of the driven gear also reduced the PTO rattle noise. However, increasing the drag torque and mass moment of inertia of the engine flywheel or decreasing the backlash and mass moment of inertia of the driven gear are not practical due to their detrimental effects on the transmission efficiency, gear strength, and smooth operations of gears. These methods are not suggested as being appropriate for solving the PTO rattle noise problem of the tractor used in this study. Instead, we recommend considering use of a torsional damper as a means of reducing velocity variations of the PTO driveline, which was a primary cause of the PTO rattle noise.