| Spiral bevel gear transmission is a kind of transmission form with high efficiency,large bearing capacity and low noise.The surface texture of the gear affects the tribological characteristics of the friction pair surface Good tooth surface texture can improve its lubrication,reduce tooth surface wear and prolong the service life of gears By applying ultrasonic machining to traditional grinding technology,the limitations of traditional grinding can be overcome,and the gear can be machined more efficiently In this paper,the ultrasonic grinding device used in ultrasonic gear machining is studied,which is mainly divided into the following parts:1.Structural design of horn and tool head of ultrasonic grinding device According to one-dimensional longitudinal vibration theory and boundary coupling conditions,the multi-step bar structure amplitude transformer and gear special grinding wheel tool head are designed The error between the resonant frequency of the device and the designed frequency is 4.1%,and the feasibility of the device design is verified within the allowable range of engineering error.2.Based on the Rayleigh optimization method,the resonant frequency of ultrasonic horn is modified and optimized.The theoretical calculation of onedimensional longitudinal vibration energy of ultrasonic horn is calculated.After optimization,the error of ultrasonic horn is reduced to 1.15% The frequency error of grinding wheel tool head with complex cross section is corrected by response surface optimization method.The fitting equations of device frequency and magnification are calculated by orthogonal experiment with mathematical method.This method can make the frequency error between theoretical frequency and modal calculation less than 0.1%,and the optimization effect is obvious.3.The vibration characteristics of ultrasonic grinding device under load are analyzed and verified Based on the transfer matrix of the transformer,the ultrasonic transformer and the grinding wheel tool head are unified,and the theoretical model of the vibration system is established to calculate the relationship between the load and the frequency amplification of the input impedance Using ANSYS simulation software,the tool load and force load are simulated and analyzed The simulation results show that the influence of tool load on the resonant frequency of amplitude transformer is reflected in the larger the mass,the greater the frequency deviation;It has little influence on the magnification and is basically stable at about 2.6 Under force load,the resonant frequency of the amplitude transformer shows an upward trend,but the magnification shows a downward trend,but the change is not obvious within the range of grinding force,which verifies the rationality of the no-load design method Simultaneously monitoring the frequency of ultrasonic device can effectively evaluate the machining quality and provide theoretical guidance for machining technology. |
