GEAR RATTLE MODELLING AND MESHING GEAR TEETH BEHAVIOUR ESTIMATION CONSIDERING LUBRICATION INFLUENCE

摘要

Gear rattle occurs inherently in a powertrain consisting of an internal combustion engine and a manual type transmission. A meshing gear pair with backlash is excited by fluctuation torque in the powertrain. Gear rattle mechanism is described with a simple backlash model. Lubrication system works as drag force and damping factor in the concept model. A gear rattle model was introduced based on the concept and constructed for a gear box system. The model calculates meshing gear pair's behaviour such as mesh displacement and impact force between meshing teeth in time domain. A five speed gear box was tested on a test rig where lubricant temperature was closed loop controlled and fluctuation input torque was also controlled. Drag torque with various lubrication conditions was measured and the drag torque model was calibrated with the measurement. Rattle threshold torque is the input which separates teeth contact between meshing gear pair. The rattle threshold was correlated for various input torque with acceleration measurement on the gearbox housing. Impact force at teeth contact is calculated in the model, however correlation work for the force is still challenging. The developed gear rattle model is sufficiently practical and effective tool for transmission R & D process.