Investigation On Lapping Process Of Spiral-bevel And Hypoid Gears

Spiral-bevel and hypoid gears with driving smoothly and high strength are widely used in driving between crossed axes, such as vehicles, machine tools, helicopter and mining machinery. With the developments of gears orienting toward higher precise, speed and strength, lower noise and miniature, it are required that the higher material and manufacturing technology. The lapping is an important precise and finish machining approach in the spiral-bevel and hypoid gears manufacturing process. As the poor material removal rate and the low precision of the conventional lapping process is becoming an obstacle of improving lapping efficiency and quality, it is very necessary to improve further the precise machining level and efficiency. The ultrasonic lapping has already widely used in the precise machining of the other area. The ultrasonic lapping introduced into the precise and finished machining of the gears can make the lapping machining of gears yield well. In this dissertation, the conventional lapping process has been investigated further and systematically, and the ultrasonic lapping of gears (ULG) is firstly presented and explored, the main contents and achievements include:Based on TCA (Tooth Contact Analysis) and the gear mating theory, the lapping kinematics model is setup, which is necessary to displace the pinion in relation to the gear member in a manner that moves the tooth contact over the entire area of the tooth surface. The rolling tests prove that this setup model can control precisely the displacement of the lapped area in the tooth surface and keep the even backlash. Based on LTCA (Loaded TCA) and the gear mating kinematics, the effects of the main process factors on the tooth surface lapping, such as the tooth surface contact stress, the tooth surface sliding coefficient and the contact lapped probability have investigated, then the lapping boundary at tooth surfaces and the estimate standard of the general lapping rate on tooth surface have determined. The material removal mechanism of the lapping,the mutual form-correction due to the lapping are investigated. The effects of the lapping on the transmission errors, and their relations to the vibration and noise are analyzed, then the dynamics model of the lapping of gears is established and solved, the dynamic lapping force is calculated. Finally, the lapping experiments and the tests of production tooth form have been done, the effects of lapping on the tooth profile precise, the pitch variation, the tooth contact and dynamic performance have been investigated.The mechanics of the ultrasonic wave transmitting and reflecting at the tooth surface has been studied by elastodynamics, and a dynamic model of the ULG has been established. The material removal mechanics of the ULG have been investigated, and a material removal model has been setup. The effects of the insensitive vibration cutting mechanism on the lapping quality and precise have been analyzed. The acoustic system characteristics of the ULG has been investigated, and the acoustic system for the ULG has been designed by...