| Rear transmission system has been the key subsystem of marine power installation,which determines an important role in the performance of the whole warship.With the development of marine power rear transmission system(MPRTS)to high speed and heavy haul power,the gear scuffing failure caused by temperature rise of teeth surface has become one of the main failure modes.Therefore,the analysis on gear anti scuffing loaded performance(ASLP)is an urgent problem to be solved at present stage of marine engineering.The calculation method of teeth surface scuffing intensity of MPRTS has not yet been very mature and unified,the influence of gear thermal scuffing failures caused by teeth surface instantaneous contact temperature are on the normal operation and working performance of warship are more and more prominent,but domestic researchs in this field have more neglected the influence on gear ASLP.In addition,the thermal scuffing failures have the characteristics of sudden and unpredictable.At present,more accurate calculation and verification are urgently needed to improve the reliability of MPRTS.This paper focuses on MPRTS as the research object,analysis on mixed thermal elastohydrodynamic lubrication(MTEHL)of ASLP.The research results of the paper have important theoretical and practical application value for gear teeth surface ASLP and anti-scuffing optimized design of complex MPRTS.The main research contents of the paper are as follows:For the given gears structural parameters and marine transmission forms,the ISO and AGMA standards limits are proposed,and these parameters of the lubricating oil viscosity-pressure and viscosity-temperature,gear load sharing and teeth profile modification are concerned in consideration of real time full conditions operating of MPRTS.The improved algorithm of alternately meshing teeth surface temperature of gears with heavy load and high speed is derived.The algorithm can meet the above two criteria and ensure that the alternating contact areas along meshing lines at several feature points mixed thermal elastomer lubrication characteristics are better.The instantaneous temperature rise and minimum film thickness of teeth surface in thermal steady state meshing time domain are discussed,and analyzed the influences of these parameters such as gear modification,modification coefficient and modulus on teeth surface instantaneous contact temperature,the time varying laws of teeth surface contact temperature and oil film thickness along meshing line are revealed,and the results are compared with different marine power rear transmission modes.The research results show that the ISO and AGMA standards are always higher than improved algorithm of this paper in an alternating gear meshing cycle period.Especially at the ends of meshing in and meshing out,it is proved that the accuracy of the improved algorithm is slightly higher than that of the ISO and AGMA standards.In the paper,the MTEHL characteristics of marine gears have been analyzed.Based on the Hertz contact thermal conductivity theory and numerical simulation method,a MTEHL model of alternating meshing line loads has been established,the influence of meshing surface friction coefficient of transmission system on thermal steady state lubrication behaviors is discussed,the gear meshing interval is determined and the load sharing coefficient is considered.The loads distribution and variation laws of teeth surface contact along the meshing line are revealed,the oil film temperatures at meshing nodes are used to solve the initial temperature of mixed thermoelastic lubricating oil film temperature field,the instantaneous temperature rise and oil film temperature distribution and time varying laws of teeth surface along alternating meshing line are obtained by solving mixed thermoelastic lubrication equations.The effects of different parameters on instantaneous temperature rise of teeth surface are studied.The gears ASLP of MPRTS are studied based on MTEHL theory.The evaluation criteria and design method of marine gears ASLP are comprehensive analyzed.The time varying laws of teeth contact temperature with different transmission modes are studied by numerical simulation method.Considering the MTEHL characteristics of gears meshing contact areas,the gears instantaneous temperature rise and oil film thickness distribution of MPRTS are obtained.The influences of various gears and oil parameters on the MTEHL characteristics are mentioned,and then the syntheses of the ASLP of herringbone gear pair are comprehensively determined.The secondary development of MATLAB and VB software to solve the practical problem of MTEHL characteristic s have been adopted,and the ASLP analysis and calculation software of the MPRTS gears have been developed.Considering the heat transfer relationship between the components of MPRTS,based on the thermal node network method,the analysis models of the thermal nodes branch interconnection in gear transmission system are established.Different forms of transmission systems are divided into nodes and parameter mode ling to determine the thermal transfer network,thermal transfer relationships and thermal flow balance equations for the MPRTS.The thermal steady-state temperature fields of each important position are obtained and compared with the corresponding data baded on the temperature distribution laws under different working conditions.It will provide detailed theoretical data for ASLP analysis of high speed and heavy power gears.The thermocouple temperature measuring system is used to real time monitor with the tooth surface and subsurface temperatures of gears in alternating meshing process on closed power flow transmission experiment platform.The surface and subsurface temperature measurement data of gears teeth under different working conditions are collected and compared with the corresponding theoretical calculation results.The calculated values obtained by this dissertation are appropriate for the experimental data,which can verify the correctness of the analysis of the MPRTS gear anti scuffing loaded performance. |
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