Dynamic Analysis Of Universal Milling Head Ball ’Bearing-spiral Bevel Gear System

High-end CNC machine tools has become the aerospace,automotive,equipment manufacturing and other manufacturing areas of the development of the core equipment.Universal milling head as a CNC machining center of the main working parts played a very key role.It is of great significance to improve the performance of the universal milling head system and improve the stability and reliability of the machine tool system by analyzing the dynamic performance of the universal milling head ball bearing-spiral bevel gear system.This article comes from the National Natural Science Foundation of China "high-performance rolling bearing-spiral bevel gear system flexible multi-body contact dynamics"(11462008).Based on the Multi Body Dynamics(MBD)and finite element analysis(FEA)method,a universal milling head ball bearing-spiral bevel gear system with flexible deformation of the ball bearing cage and flexible deformation of the spindle was established.Multi-body dynamics model,the dynamic characteristics of the system are analyzed.The main research work is as follows:(1)Based on the classical Hertz contact theory,a rigid-flexible coupled multi-body dynamics model of angular contact ball bearing considering the flexibility of the cage was established in ADAMS.The effects of different radial loads and axial loads on the dynamic characteristics of angular contact ball bearings are analyzed.It is found that the increase of axial load has a significant effect on improving the stability of bearing operation.The increase of radial load will reduce the stability of bearing operation.(2)The multi-rigid body dynamics model of pairs of double angular contact ball bearings and the multi-rigid body dynamics model of double row angular contact ball bearing are established.The dynamic characteristics of two different types of angular contact ball bearings under the same boundary condition are compared and analyzed response.It is found that pairs of double angular contact ball bearings have a similarity to the dynamic response of double row angular contact ball bearings,but the latter is more stable.(3)Based on the helical bevel gear assembly relationship established by UG,the angular contact ball bearings with 45 0 and 90° angle of intersection are established by using the method of spring-damping as the integral equivalent of angular contact ball bearing joint.The dynamic response of the system under different equivalent stiffness values is analyzed.It is found that the dynamic performance of the system is more stable with the increase of the equivalent stififfness of the bearing.By comparing the multi-rigid body contact dynamics model of the real angular contact ball bearing-helical bevel gear based on the MBD method,it is shown that the dynamic contact characteristics of the multi-body within the ball bearing have an important influence on the dynamic performance of the spiral bevel gear transmission system.Bearing joint equivalent spring-damping modeling method can not be explored(4)A rigid-flexible coupled multi-body dynamic model of universal milling head bearing-spiral bevel gear system with flexible cage and flexible spindle was established.The dynamic characteristics of the universal milling head bearing spiral bevel gear system under low speed and heavy load and high speed light load are analyzed.By the acceleration of the gear vibration of gear contact force,ball bearing contact force and cage stability calculation shows that the helical gear vibration acceleration spectrum showed the meshing frequency and frequency,low speed and heavy meshing characteristics of spiral bevel gear with high speed and light load stability;dynamic characteristics of bearings in light load speed when compared with the low speed and heavy load instability.