Analysis Of The Failure Factors About Crane Speed Reducer

The speed reducer is a very important part of the crane, because of its failure may cause the whole crane destroyed, in order to avoid such problems occur, the high speed shaft in the speed reducer of MQ4599crane hoisting mechanism is researched, guide with theoretical knowledge of theoretical mechanics, finite element method, structural mechanics and mechanical vibrations, with the ANSYS finite element analysis software, combine with mathematical modeling and computer modeling methods, base on previous existing research results, the whole crane speed reducer is analysised to find out its weak structure, and also researched the high-speed shaft failure factors, this may have a significance in practical engineering application, the main research topics include the following:(1)Use theoretical mechanics and mechanics of materials knowledge, analysis brake wheel inertia force, and axis misalignment, the brake torque to the reducer high speed shaft strength failure, establish the relationship of each parameter with the high speed shaft strength.(2) Analysis the course of the speed reducer's high speed shaft working, because the high-speed rotation of the couplings, gears and brake wheel have great moment of inertia, in this case I analysis the force of the entire shafting, and establish the balance equations of the system, to arrive at the moment of inertia for high-speed shaft's failure.(3) Research the misalignment of coupling or the motor shaft and the reducer high speed shaft, when it misalignment, I find the impact of the system vibration for the inertia force and damping force respectively, the bending vibration made by inertia force of the system, and the closer from bearing, the stronger the vibration, but the torsion vibration made by the damping force, this situation is the opposite.(4) Analysis the failure of high-speed shaft eccentric disk, the greater the eccentricity, the greater the deflection of the shaft; and also studied the impact of several different types of coupling, such as rigid couplings, flexible couplings, because the rigid of the couplings is different, make the critical velocity different, this is useful for selecting couplings in practical engineering; finally, simply analysised the impact of the bearing and the base of the reducer to speed reducer's failure.(5) With the help of ANSYS11.0software to establish the solid model of the whole crane speed reducer box, because the gear contact simulation is very complex, during establish the mode, the contact between the gears is got rid of, I use LINK10and BEAM4unit to simulate the bearing respectively, with static analysis of the cabinet of the gear box and shaft, I find the weak structure in high-speed shaft, so in the process of the speed reducer working, its high-speed shaft most likely bring problems, play a role of a verification of the previous theoretical analysis.