The hydrodynamic bearing is a machine-building unit in which the main load falls on a thin layer of insulating flushing fluid, pumped with a lubricated shaft into the structure. Often the product is called hydraulic.
Modern hydrodynamic bearings are used in various precision mechanisms, especially when conventional roller or ball varieties do not meet the requirements that apply to them to ensure the operation of individual units or structures.
For example, the use of hydraulic elements allows for minimal vibration, low
noise, while the devices have a long service life. These types of bearings in the process of further improvements and developments are becoming increasingly competitive, since the cost of their production is constantly reduced.
Unlike hydrostatic products, a hydrodynamic bearing has a slightly different operating principle. If in the first case the working fluid pressure is produced by means of a special pump, then in the latter case, self-lubrication is performed when the working shaft is rotated. It should be noted that the self-lubrication effect itself occurs only when certain shaft rotation speeds are reached, which are indicated in the product passport.
Otherwise, the thickness of the lubricant under the shaft will be insufficient, which will lead to an increase in friction forces, and ultimately cause premature wear of the mechanism. Thus, in order to exclude these situations, which often arise, for example, when starting and stopping the device, it makes sense to use a special starting pump, which will be used in the described transient conditions.
Hydrodynamic bearing has several advantages. Firstly, the products are reliable and simple in design.
Usually in their device they consist of an inner and outer ring with a toroidal shape; at the joints of the product they have hermetic seals. Thanks to the improved design, the hydrodynamic bearing has practically no operating costs (or they are minimal). The mechanism is characterized by a long period of service.
In the manufacture of products, the requirements for the level of accuracy are much lower than in the manufacture of ball or roller types. The noise level from hydraulic devices is significantly lower than the sound coming from rolling bearings. Products produce minimal vibration. Due to design features, they have high damping ability.
The disadvantages of the products include their high sensitivity to inaccuracies arising from the manufacture of shafts. In addition, they have a significant loss of energy.
Hydrodynamic bearings are used in computer devices. With their help, the hard drive works, as well as the cooling fans of the system unit. In addition, they are used in nuclear reactors, they drive the elements of metalworking machines.