Study On Structure And VIBRATION&NOISE Of Drive Axle About Clean Machines

As one of the key components of the cleaning machinery, the cleaning machinery drive axle requires high transmissionefficiency, compact structure, light quality and low vibration noise. With the improvement of people’s life, the demand of the environmental noise is becoming higher and higher. It is necessary to carry out a design for high transmission ratio, light quality and low vibration noise cleaning machine drive axle. Among all the goals, to solve the vibration noise problem is particularly prominent and important, because cleaning machine is mainly used in conference rooms, exhibition hall and other places. This subject mainly design clean machinery drive axle structure, analysis and control vibration noise.and optimize the design of drive axle housing structure, achieving the purpose of reducing structure surface radiated noise. The main research contents and conclusions are as follows:1. Determine the helical gear transmission design solution, analyse of the static pressure of key components of the drive axle of shell and gear mesh when cleaning machinery drive axle are applyed the vertical force, traction force and lateral force separately under working condition. The solved maximum strain of the drive axle of housing is0.47mm, meeting the standard provisions of the state; Structure under the maximum beared stress of398.3MPa and540MPa less than the allowable stress of material. Input shaft gear of the maximum contact stress is809MPa, the output shaft gear contact stress is550MPa, the biggest input shaft gear maximum stress is greater than the yield limit of material about (780MPa), easy to make the structure failure.2. The dynamic analysis of structure to carry out the finite element calculation mode, experimental modal analysis. Contrast analysis proves the effective reliability of the calculating modal analysis and the feasibility of the experimental modal analysis. Solution of drive axle shell before4order natural frequencies of714.42Hz,1065Hz and1325Hz and2203Hz. Central drive axle at the long end relative displacement, the biggest overall stiffness is insufficient.3. The drive axle drive source, vibration transfer path, the vibration response of mechanism analysis. Determines the drive axle housing is drive axle’s noise, the vibration of the gear mesh generation as the main excitation source. In combination with using near field sound pressure method, frequency spectrum analysis method for vibration noise experiment, determine the critical frequency of drive axle noise radiation at73hz,476hz and954hz,1421hz and1900hz.4. Establish the transient response of the drive axle model, the acoustic radiation of. finite element model, and carried out structural transient response analysis of sound radiation analysis. Solving the structure at78hz,920hz and1360hz,1850hz and2160hz,2300hz have bigger motivation response, noise and vibration tests compared to verify the effectiveness of the structural transient analysis. Identified in the frequency of920hz and1750z for maximum radiation noise frequency point. To carry out based on the sound power of the drive axle shell of the panel acoustic contribution analysis, determined the drive axle shell panel5,6,1,2as the main radiation area, and the panel5(central bridge shell long side),2(bridge shell abdomen) have larger contribution to the sound pressure of main peak frequency.5. In order to reduce the structure on critical frequency sound pressure series and the frequency band sound pressure values as the goal, from the shape of the stiffened plate, the thickness of the stiffened plate, bridge shell abdominal rigidity and damping noise reduction optimization of structural noise simulation analysis. Ultimately determine the structure reinforcement plate to change shape; stiffened plate thickness is7mm, inside the bridge shell belly full filling at the same time the optimal high impedance of the mild steel material. The structure in the sound pressure level of930Hz noise is reduced from69.7dB to53.64dB, the sound pressure level and make the structure noise around the1750Hz value decreased from77.3dB to63.44dB, the response spectrum curve of the sound pressure level is relatively smooth, effect.Also from the aspects of structure craft, structure installation support structure vibration noise optimization method is proposed.