| This essay focuses on one type of four-wheel drive automobile transfer case rolling bearing research by using theoretical calculation and computer numerical simulation to make research on driving dynamic,structural strength and stiffness emulation,bearing lubrication and stress distribution analysis.Firstly,the essay builds a mechanical driving model for one type of four-wheel drive automobile’s transfer case,by using theoretical formulation calculation to get the transfer case inner gear’s meshing force,the rolling bearing’s three-direction force under the Cartesian coordinates and at the same time building transfer case driving model in ROMAX,setting its input torque and rotate speed to measure the model’s simulation precision by meshing.After finishing analyzing theoretical calculation and simulation,the essay gets a conclusion that the results by theoretical calculation and simulation are fundamentally at the same magnitude order.Because theoretical calculation may ignore restraints,there some differences between theoretical calculation and ROMAX simulation and they are below 10%.So both the theoretical calculation built driving model and coordinates transfer are accurate and reliable.Secondly,it implements finite element analysis on transfer case.Traditional transfer case simulation ignores the influence of transfer case inner parts act on case which has cost a little difference between the simulation and actual action result.Cause involving gears meshing,tapered rollers’ touch with bearing inner and out circle and interference between the shaft and bearing,the traditional transfer case finite element analysis has made it too complicated to build model,at the same time directly increased calculation grid quantity,the cost and difficulty of calculation.The essay has considered the influence of the transfer case inner parts on case,by simplifying the transfer case parts model to get simple efficient finite element model and assure the calculation precision at the same time.Conclude from the finite element simulation: the distribution of stress on case is very little and there is no stress concentrate;the distribution of stress on the input bearing out circle is relevant low;while the small gear bearing is big.Bearing out circle biggest stress is at the end of output shaft near bevel pinion.And then use Fuji pressure testing device to make contact stress measurement on transfer case inner bearing out circle,put Fuji prescale between roller bearing and case,well assemble transfer case and fix it at the traditional experiment Tab.le and run it.Through control system to control the input end’s torque and speed,after rotating for a peorid of time,disassemble the transfer case;take out the Fuji Prescale film and analysis experiment result by using professional analyze and scanned software.Finally,we can get the out circle stress distribution while bearing rotate.It testifies the precision of finite element simulation by comparing simulation analyze with experiment result at the same condition.Finally,make lubrication analysis on transfer case roller bearing through theoretical formula,build transfer case roller bearing lubricate mathematic model and get the transfer case roller bearing contact area’s oil thickness and lubricate oil stress by difference method.Analysis bearing with big contact stress has big bearing oil stress and small oil gap.After through mechanical and lubricate simulation get roller bearing functional parameter which has acted as guidance to roller bearing redesign and improvement. |
