Influence Of Torsional Vibration And Vibration Reduction Research Of Coupling On Internal Combusion Engine Shaft

The development of internal combustion locomotive has ushered in both opportunities and challenges,after the concept of "the belt and road,the first railway" puts forward.The coupling of the internal combustion engine shaft is the key part to connect the shaft system and transmit the torque.During the actual operation of the diesel locomotive,the phenomenon of torsional resonance and coupling failure occurs frequently under start-up conditions of shaft.Therefore,the use of shaft coupling is related to the safety and reliability of the shaft system,which has great research significance.Typical diesel engine powertrain shaft coupling is taken as the research object.The parameter characteristics of large stiffness couplings and high elastic couplings have been compared.The effect of coupling on torsional vibration of diesel engine shafting has been studied by using the method of shaft torsional vibration test and simulation calculation.The stiffness of the rubber coupling,coupling spring damping and stiffness of diaphragm coupling about the torsional vibration characteristics of engine shafting have been studied according to the simulation and experimental results.The optimal matching strategy of three kinds of coupling and shaft system has been analyzed.Although the coupling mode of the three coupling shafts avoids the 3.0 main order excitation of the internal combustion engine,it will resonate with the 6.0 order or 1.0 order of the internal combustion engine.Aiming at the deficiency of the conventional phase difference torque meter,the coupling force test method has been put forward based on coupling dynamic torsion angle difference and angular acceleration.The torsional vibration force of shaft coupling,the motor rotor inertia moment and collision moment under the condition of transition have been studied by testing the torsional angle difference.When the spring damping coupling shaft is in start-up condition,the peak-peak value of its maximum interaction twist angle difference can reach 31°,and the main passive side of the maximum twist angle can reach 15.7 °.It is confirmed that a transient collision with the two side of the coupling.The maximum inertia moment which the spring damping coupling is subjected to has been reached 9914 Nm under start-up conditions.Aiming at the failure situation of the spring damping coupler in practical application,the bolt preload of coupling spline has been checked.The finite element model of the spring damping coupling has been established.Based on the test result of the coupling’ torsion angle difference,the maximum moment of inertia of the coupling in the start-up condition is obtained by the force analysis of the coupling.The stress at the failure place of the coupling has been analyzed.The coupling service life has been estimated by the S-N method.Although the stress at the failure place is less than the yield limit of the coupling,it’s larger than the limit of fatigue strength,the coupling may be destroyed.A new optimization strategy of the continuous variable stiffness coupling is proposed,and it has been successfully applied in the shafting of a type of internal combustion engine.Shafting matches continuous variable stiffness coupling,which makes the shaft coupling mode avoid the main harmonic excitation of 3 and 6 of the internal combustion engine as well as the harmonic vibration of the second harmonic and the second harmonic of 0.5 and 1 harmonics.The torsional amplitude of each shaft part is effectively controlled,and the torsional vibration amplitude can also meet the limit value under the fault condition.The twist angle difference between the ends of the coupling under start-up condition is also optimized.To sum up,in this paper,the coupling force test method has been put forward based on coupling dynamic torsion angle difference and angular acceleration,which can be used for the test of regular coupling force and impact torque.The stress analysis of coupling under different condition is completed on the basis of measuring the shaft coupling torsion angle difference and the different working conditions.A new optimization strategy of shaft coupling is proposed,and the continuous vibration stiffness coupling is used to optimize the torsional vibration characteristics of the shaft system,and the optimization results are excellent.