The working performance and transmission reliability of the straight bevel gear system will be affected by various excitations of the straight bevel gear system. The internal excitation (error excitation, stiffness excitation, meshing impact excitation, etc.) is closely related to the model. After the model is built according to the given parameters, the relative position and motion relationship of each component will also be determined.
Various errors such as manufacturing and installation of straight bevel gear can cause error excitation in straight bevel gear transmission, which is the main internal excitation. In the study of dynamic characteristics, due to the existence of these errors, the straight bevel gear pair can not drive and mesh in the correct way, the actual meshing tooth profile deviates from the ideal meshing position, and the instantaneous transmission ratio of straight bevel gear changes, resulting in transmission errors. Transmission error is an important factor affecting the meshing quality of straight bevel gear transmission. At the same time, it can also make the transmission system produce vibration and noise.
Straight bevel gear transmission error includes static transmission error and dynamic transmission error. Not only the above errors will lead to transmission error, but also the inertia, dynamic load and variable stiffness in the process of straight bevel gear transmission will affect it. In the dynamic analysis, the measured error numbers are generally used to express the error excitation, but the RomaxDesigner software used in the study of straight bevel gears can analyze and measure the transmission error curve of meshing gear pairs according to the defined load spectrum, and then take the transmission error as the excitation to analyze the system vibration characteristics caused by it.
When the differential straight bevel gear pair is driven, the number of teeth entering the meshing at the same time is constantly changing. In the process of tooth transmission, there are contact deformation and bending deformation, forming a time-varying meshing stiffness. Therefore, the meshing stiffness is the parametric excitation caused by the elastic deformation of straight bevel gear. The smaller the elastic deformation between teeth, the greater the meshing stiffness of teeth. The change of tooth meshing stiffness will also make the transmission error of straight bevel gear transmission system.
In the meshing process of straight bevel gears, various errors and elastic deformation make the straight bevel gears engage abnormally, the position of nodes on the meshing line changes, and the base joints of adjacent teeth are different when driving the driving and driven wheels, resulting in meshing impact and meshing impact. This meshing impact will also excite the straight bevel gear system, aggravate the vibration and noise of the system, and affect the working performance of the transmission system.
In romax software, the excitation force mainly comes from the transmission error. In NVH analysis setting, the excitation including the meshing torque of straight bevel gear can be set.
In addition to the internal dynamic excitation of the straight bevel gear system, the external factors of the straight bevel gear system (driving torque of the motor and resistance torque of the load, etc.) will also produce dynamic excitation to the straight bevel gear system, which will also have varying degrees of influence on the dynamic characteristics of the straight bevel gear transmission.