What is the concept and working principle of dynamic and static pressure spindle

What is the concept and working principle of dynamic and static pressure spindle? Hydrostatic spindle is a sliding spindle, which uses pressure pump to press pressure lubricant into the small gap between spindle and shaft. According to different lubrication performance, it can be divided into non full fluid lubricated sliding spindle, full fluid lubricated sliding spindle and non full fluid lubricated sliding spindle. Another fully fluid lubricated journal spindle is hydrodynamic spindle, which has the characteristics of high rotation accuracy and high bearing capacity at any shaft speed. However, compared with the moving journal spindle, it needs a complete set of spindle. External oil pump system. According to the type of lubricating oil, they can be divided into two categories: one is hydrostatic spindle, which mainly uses oil as lubricant, and the other is Aerostatic Spindle, which uses natural gas as lubricant and mainly uses air as lubricant. Most of them are hydrostatic spindles and aerostatic spindles have a small application range. It is mainly used for very high-speed mechanisms, such as gyroscopes.

The structural lubrication system is composed of oil tank, lubrication pump, filter, safety valve, safety valve, accumulator, throttle valve, oil chamber, sealing surface, etc.

The application range usually requires low-speed operation, high bearing capacity, high rotation accuracy and high speed. Such as all kinds of heavy machine tools, as well as high-precision machine tools.

Working principle of hydrostatic spindle

The sliding spindle with static lubrication is called hydrostatic spindle. The principle of static lubrication is different from that of dynamic lubrication. The hydrostatic spindle is supplied with pressure oil by the external lubricating oil pump to form a pressure oil film to bear the load. Although many hydrodynamic spindles also use lubricating oil pumps to provide pressure oil, their performance is different. The most obvious is that the oil supply pressure of hydrostatic spindle is much greater than that of dynamic spindle.

One of the main features of the hydrostatic spindle is that the spindle oil film can also be established in a completely static state, which can ensure that there is no direct contact between the two surfaces. In the initial stage, it is absolutely impossible for the hydrodynamic spindle.

Therefore, when using the hydrostatic spindle to start the rotor, the hydrostatic lubrication system must be started first.

In the operation of hydrostatic spindle, hydrodynamic effect may also occur due to the relative motion of friction pair. When the hydrodynamic action reaches a certain proportion, the spindle becomes a hybrid spindle of hydrodynamic and hydrostatic.