Analysis Of Tooth Surface Wear And Vibration Response Of Locomotive Transmission Gear

The locomotive transmission gear is a key component of the locomotive operation,and it is often under high-speed and heavy-load operating conditions,so higher requirements are put forward for the service performance of the gear.Tooth surface wear,as one of the common faults of gears,will reduce the efficiency and precision of the transmission system,and even affect the safe running of the locomotive.Therefore,it is necessary to study the wear characteristics of locomotive gear tooth surfaces.Due to the particularity of locomotive operating conditions,there are internal and external factors that affect the gear transmission system of the locomotive,so it is necessary to analyze the influence of internal and external excitations on the wear of the gear tooth surface of the locomotive.Finally,in order to ensure the stability and reliability of the gear transmission system,it is necessary to analyze the vibration response and mode of locomotive gears with tooth surface wear faults.Based on this,this paper takes locomotive transmission gear as the research object,and conducts research through numerical method and finite element method.The main research work of the paper is as follows:(1)Based on the Archard wear formula and Hertz contact theory,a numerical simulation model of locomotive gear tooth surface wear considering the dynamic wear coefficient was established,and the simulation calculation was carried out.The calculation shows that the wear depth of the driving and driven gears is the largest near the tooth root,and the wear depth is 0mm at the pitch line,and the wear depth of the alternating single and double teeth on both sides of the pitch line has a sudden change.Then the influence of gear parameters on tooth surface wear was analyzed.The results show that increasing the modulus,pressure angle,tooth width and transmission ratio or reducing the load torque can slow down the tooth surface wear.(2)In order to further explore the influence of internal and external excitations on the tooth surface wear of locomotive gears,the UMESHMOTION subroutine was redeveloped using the finite element software ABAQUS,and combined with the ALE adaptive grid,the finite element simulation model of tooth surface wear of locomotive gears was established.After the simulation,the tooth surface wear information was extracted by MATLAB,and the results were compared with the numerical simulation results.It is found that both had the largest wear depth at the tooth root,but almost no wear occurs at the pitch line.Then,the influence of friction coefficient and center distance error on tooth surface wear was studied by changing the model parameters.And the research shows that with the increase of the friction coefficient,the total amount of wear depth increases continuously,and the wear depth at the pitch line remains unchanged,and the wear depth near the root of the tooth increases with the pitch line as the boundary,and the opposite is true at the top of the tooth.The decrease,and the increase of the wear depth are mainly concentrated at the tooth root.When the center distance error is negative,the total wear depth increases with the decrease of the center distance,while when the center distance error is positive,the total wear depth hardly changed with the increase of the center distance.Finally,the locomotive dynamics model was established based on the multi-body dynamics software,and the vertical vibration displacement of the driven gear under the rail corrugation excitation and the wheel polygonal excitation were simulated respectively,and loaded into the finite element model for wear simulation calculation.It is found that the existence of excitation deepen the wear at the tooth root,and the greater the vertical vibration displacement generated by the excitation,the greater the impact on tooth surface wear.(3)Based on the energy method,the formula for calculating the meshing stiffness of gears with tooth surface wear was derived,and then the influence of different degrees of tooth surface wear on the time-varying meshing stiffness of gears was studied.The study found that the tooth surface wear reduce the meshing stiffness of the gears.With the increase of the wear degree,the greater the stiffness reduction,the stiffness of the tooth top is more affected than the tooth root position.On this basis,a six-degree-of-freedom gear dynamic model was established,and the time-varying meshing stiffness of the gear was brought into the dynamic equation for solution to study the vibration response of gears with tooth surface wear faults.It is found that the wear fault has little effect on the gear vibration response and transmission error,and only changes in the amplitude.Therefore,statistical indicators were used to evaluate the impact of different degrees of wear on the signal.It is found that the skewness and root mean square value in the frequency domain have relatively strong sensitivity to wear faults.(4)The finite element model of locomotive gear with different degrees of tooth surface wear was established in ABAQUS software,and the modal analysis was carried out.The results show that the wear of the tooth surface leads to a widening of the natural frequency band of the gear,and attention should be paid to avoiding this frequency band during design and use to avoid resonance.However,the wear of the tooth surface has little effect on the vibration shape,and the deformation of the tooth top is greater than that of other parts of the gear.Therefore,it is necessary to pay attention to strengthening the strength of the tooth top during gear processing.