Vibration Simulation Analysis And Noise Control Of Idle Gear System In Engine

Timing gear system is an important part of the internal combustion engine and the vibration and noise caused by timing gear system contributes a lot to engine vibration and noise. These timing gears are subjected to higher speed and heavily fluctuated load since they are mounted on cantilevered shafts and are responsible for transmitting nearly all the fluctuated torque outputted by crankshaft. The instant alternating impact load brings more deformation and vibration to the teeth and excites high noise level.Timing gear noise is the principal cause for diesel engine. Therefore, the vibration and noise control of timing gear system is significant to reduce entire engine vibration and noise and has a huge practical value for the improvement of the performance of the engine.On the basis of timing gear system structure, this paper focuses on the vibration and noise study of the idle gear train, which is one of the five gear chains in the timing gear system. To achieve the target of reducing vibration and noise, the paper mainly taking the method of optimizing gear teeth to reduce the internal gear excitation.The paper analyzes the internal excitation of idle gear system in engine. The main work carried out as follows:â‘  Frequency response function tests of the engine gear system are conducted to gain the frequency response functions of variable transmission route in engine. The aim of the test is to judge the influence of transmit routes to the gear vibration and noise.â‘¡ A simulation model of the engine idle gear system is established, which is also verified by the frequency response function tests results.â‘¢ In consideration of the transmission error and load distribution on the teeth surface, an optimization project about tooth profile modification and tooth lead modification are proposed. The optimization project is primarily verified by tooth time varying engaging force.â‘£ Considering radiated noise caused by engine idle gear system, an idle-gear-system acoustic simulation model is established. Noise numerical calculation about engine idle gear system is conducted to gain sound pressure level curves and cloud chart in frequency domain, which verifies the teeth optimization project.