Influence of bearing temperature rise on high speed machining2018-08-14
1. The influence of bearing temperature rise on finish machining:
Bearing is an important part of motorized spindle in high-speed machining. In high-speed machining, the thermal characteristics of motorized spindle is a major factor affecting the machining accuracy, and directly affects the improvement of motorized spindle speed. In the temperature rise of the motorized spindle unit, the temperature rise of the bearing is a very important part. The temperature rise and temperature distribution of bearings have a great influence on the performance of bearings. It will affect the assembly of bearings, the working clearance of bearings and the performance of lubricants. Higher temperature will cause deterioration of bearing lubrication and lead to premature failure of bearing. Therefore, the thermal analysis of the bearing system can help us to choose and use the bearing reasonably, and provide a basis for the failure and failure analysis of the bearing system.
2, oil and gas lubrication three parameters:
The three main parameters of oil-air lubrication system are: the kinematic viscosity of lubricating oil, compressed air pressure and compressed air flow rate.
At present, the precision angular contact bearings which are suitable for high speed and can withstand both radial and axial loads are usually used in electric shaft bearings. Experiments show that the three main parameters of oil-air lubrication system have obvious influence on temperature rise of precision angular contact bearings. The following conclusions are drawn from the experiments:
1) The viscosity of lubricating oil affects the temperature rise of the bearing by the friction heating inside the bearing. With the increase of the viscosity, the temperature rise of the bearing will increase, and the trend is more obvious in the high speed section. However, with the further increase of the viscosity, the temperature gradient of the bearing will decrease.
2) Compressed air pressure and compressed air flow affect bearing temperature rise by convection heat between compressed air and bearing. In the range of compressed air pressure, bearing temperature rise decreases with the increase of air pressure, but this trend is not obvious.
3) Increasing the compressed air flow rate can reduce the bearing temperature rise, and with the increase of rotational speed, cooling effect will become more and more obvious.