A Research On Design Of Balancing Device And Strength Of Crankshaft For Low Speed Single Cylinder Diesel

Balance system can effectively control the vibration of the single cylinder diesel and crankshaft is one of the most important components of diesel.Both of them are direct affect the engine performance.If we don’t use the balance system or the strength of crankshaft is not up to the requirements,the diesel may cause serious accidents.So it is necessary to designer the balancing system and to calculate the strength of crankshaft.This article tries to design the balance system and flywheel by modeling the related parts analyzing the dynamic performance of the single cylinder engine.Using the EXCITE software model multibody dynamics with three different balancing approach to research the effects of the balancing devices on diesel engine’s vibration.Balancing the first order reciprocating inertia force of the single cylinder diesel by analyzing vibration displacement and vibration velocity of the calculating point of choice can control the vertical vibration and improve vibration performance in other direction;Balancing the two-stage reciprocating inertia force of the single cylinder diesel can’t improve the vibration performance effectively.The analysis of the vibration of the crankshaft mass center show that balancing the first order reciprocating inertia force can control the longitudinal vibration of the crankshaft effectively and aggravate the axial vibration,but the result within the accepted range.The dynamic model of the balancing device is set up by Timing Drive.Through the results of calculation,we can know that the device runs smoothly and wear small and the speed fluctuation of crankshaft direct influence the smoothly of the device.From the force curves of the bearing we can see that the bearing force of the transmission shaft is mainly influenced by the impact force of the gear and the bearing force of the balanced shaft is mainly influenced by centrifugal force,the result within the accepted range.When calculating crankshaft strength,we use the contact algorithm.From the analysis we can see that the stress distribution of the hole on the crank arm is affected by the interference joint and that of the crank pin is affected by the connecting rod thrust which is far less than Interference force,so it is necessary to make sure the shrink range to ensure the safety work in crankshaft.First of all,we have determine the maximum value of interference fit and the minimum value of interference fit according to the thick walled cylinder theories.Then the relationship between the pressure and interference has been got through the analysis of the different interference.At last,we determine the range of the interference.