The Overall Design Research Of The Low Speed And Heavy Load Traveling Reducer

With the rapid development of construction machinery, wind power, high-speedrail and the infrastructure, gear industry in our country develops toward the directionof low speed and heavy load, high speed and heavy load. Due to the development ofmachine performance and market competition，it puts forward higher requirements tothe economy, reliability and longevity of gear transmission system. Planetary geartrain is applied more and more widely in the gear transmission field.Because of theplanetary gear train with small mass, large transmission ratio, small volume, smoothtransmission and high transmission efficiency features, and taking use of the powersplit effectively, coaxial input and output and the reasonable using method of bearingcapacity high and internal gear space volume is small; Thus, closed differential formof planetary gear train is not only suit for walking the excavator space volume limitrequirements, but also meeting the high torque at low speed, high power transmissionrequirements. Walking speed reducer is important transmission parts in walkinghydraulic crawler excavator system, long-term in the damp, high temperature, acidand alkali conditions, its design has a great influence on the performance of excavatorperformance and work efficiency; And walking speed reducer in the working processof the failure rate is higher belonging to the typical parts; So adopting scientific andreasonable method for the optimization of walking speed reducer key parameters andload handling and overall design research has important practical significance.This paper mainly researches the following aspects of walking speed reducerplanetary transmission system. In the design of closed differential planetary gear train,the distribution of gear ratios determines all levels of the bearing capacity and the sizeof the total volume of the reducer; therefore according to the design criterion of alllevels of contact strength, it considers the tooth width coefficient d, the numberof planetary gearNp, the uneven load coefficient K and the radial dimensions in the reducer volume optimization process of gear ratio distribution effect; and thecontact intensity factorkfcalculation formula of the optimal mathematic model wasestablished by volume and diameter as the basis. The gear ratio in the process ofoptimization, two adjacent outer diameter ratio, width coefficient, and all levels of thenumber of planet gears adopt the optimization method of exhaustion for global search;and compiling optimization program and achieving the optimal allocation of the gearratio are based on MATLAB software. The reasonable distribution of the gear ratio iscalculated each gear design equivalent load, and the determination of the gearfatigue design load is equivalent to a linear S-N curve, the cumulative damage theory,the fatigue equivalent damage theory; the theory of Miner and AGMA equivalenttorque load calculation method of equivalent processing of the original load spectrum,according to the function relationship of torque and the speed and the number of teethclosed differential gear train gear ratio, the input end of the load durable distribution（LDD） spectrum is converted to each gear of the actual load durable distribution（LDD） spectra; and the general design of the contact fatigue strength condition, thegear bending fatigue strength condition, a planetary gear, and tooth number matchingconditions determine the gear pitch circle, modulus, number of teeth, coefficients ofthe macroscopic parameters.The theory and method of the overall design of differential planetary gear trainclosed is not only fitted for excavator traveling speed reducer, but also suitable forwind power, rail transportation, aviation and other fields digging machine、crane andother construction machinery design.