The mechanical state of cantilever gearbox housing is different from ordinary ones due to the long arm of force caused by cantilever structure.Conventional mechanical analysis methods either took cantilever gearbox ho...The mechanical state of cantilever gearbox housing is different from ordinary ones due to the long arm of force caused by cantilever structure.Conventional mechanical analysis methods either took cantilever gearbox housing as ordinary ones or cantilever beam.Few published papers have specially focused on mechanical analysis method for cantilever gearbox housing.This paper takes a longwall shearer cutting unit gearbox(SCUG)as an example and the mechanical analysis method is investigated according to the causes of fatigue for SCUG.Force analysis model is established for finding out regions of static fatigue caused by low-frequency loads,and local resonance analysis is used for finding out regions of vibration fatigue caused by high-frequency loads.Not only bending moment but also torque caused by gear meshing forces is taken into account in the force analysis model.Vibration response is obtained from cutting experiment,and dominant frequencies of local resonance are obtained by frequency domain analysis.Finite element model of SCUG is established,and natural frequencies and strain modes are analyzed for obtaining the main vibration modes corresponding to dominant frequencies.Hence,large stress regions caused by low and high frequency loads are obtained.Results show that the worst working condition is oblique cutting,and the stress of B-B in 600 mm cutting depth can reach 166 MPa.Obviously,950 Hz,1250 Hz,and 1400 Hz are dominant frequencies of SCUG(23rd,25th and 27th natural frequencies).Generally,this paper proposes some principles for mechanical analysis method of cantilever gearbox housing.展开更多
基金National Key Basic Research Program of China(No.2014CB046303)。
文摘The mechanical state of cantilever gearbox housing is different from ordinary ones due to the long arm of force caused by cantilever structure.Conventional mechanical analysis methods either took cantilever gearbox housing as ordinary ones or cantilever beam.Few published papers have specially focused on mechanical analysis method for cantilever gearbox housing.This paper takes a longwall shearer cutting unit gearbox(SCUG)as an example and the mechanical analysis method is investigated according to the causes of fatigue for SCUG.Force analysis model is established for finding out regions of static fatigue caused by low-frequency loads,and local resonance analysis is used for finding out regions of vibration fatigue caused by high-frequency loads.Not only bending moment but also torque caused by gear meshing forces is taken into account in the force analysis model.Vibration response is obtained from cutting experiment,and dominant frequencies of local resonance are obtained by frequency domain analysis.Finite element model of SCUG is established,and natural frequencies and strain modes are analyzed for obtaining the main vibration modes corresponding to dominant frequencies.Hence,large stress regions caused by low and high frequency loads are obtained.Results show that the worst working condition is oblique cutting,and the stress of B-B in 600 mm cutting depth can reach 166 MPa.Obviously,950 Hz,1250 Hz,and 1400 Hz are dominant frequencies of SCUG(23rd,25th and 27th natural frequencies).Generally,this paper proposes some principles for mechanical analysis method of cantilever gearbox housing.
