Development and performance evaluation of a non-resonant ultrasonic vibration-assisted grinding device for ultra-high-strength gears

To address the challenges posed by the high hardness and poor machinability of ultra-high-strength gears used in aerospace transmissions, this study innovatively proposes and validates an ultrasonic vibration-assisted grinding (UVAG) method. First, based on non-resonant design theory and the Rayleigh-Ritz method, a theoretical model of the gear-specific ultrasonic vibration unit was developed to determine the key structural parameters. Subsequently, finite element analysis (FEA) was used to perform modal analysis and structural optimization of the vibration unit, leading to the successful development of a UVAG device tailored for gear grinding. Finally, machining experiments confirmed the feasibility and significant advantages of this technology. The results show that, through theoretical design and finite element optimization, the actual resonant frequency of the developed ultrasonic vibration unit deviated less than 4.5 % from the designed value, and a uniform longitudinal ultrasonic amplitude of 6 μm was achieved circumferentially on the ultra-high-strength gear. Compared with conventional grinding (CG), the UVAG demonstrated significant advantages: the normal and tangential grinding forces were reduced by 34.9 % and 31.7 %, respectively. And the grinding temperature was reduced by 37.4 %. In addition, the surface roughness of the gear tip, flank, and root were significantly improved by 24.2 %, 19.1 %, and 19.6 %, respectively, resulting in enhanced surface quality of the ultra-high-strength gears. Moreover, this method effectively reduced clogging of the grinding wheel pores and adhesion of workpiece material on abrasive grains. This study integrates ultrasonic vibration into the ultra-high-strength gears grinding process, offering a practical and valuable technological solution for the efficient and high-quality machining of ultra-high-strength aerospace transmission gears.