Types of plain bearings
The gap between the shaft and the bearing is in contact with the surface, which is called a plain bearing. It is widely used because it is a surface contact that can withstand large external forces, is shock-resistant, and has a simple structure. For example, the movable joints of the Excavator's Monster Hand.
Sliding bearings can be divided into three types according to the direction of force, namely:
1. Radial sliding bearing
The force direction of radial plain bearings is perpendicular to the central axis, which can be divided into three types according to the form:
1) Integral bearing: Integral sliding bearing is a common integral radial sliding bearing, which is connected with the frame with bolts. The internal pressure of the bearing seat bore, the oil cup is installed at the top of the bearing housing, the oil inlet hole is on the shaft sleeve, and the inner surface is filled with a bearing (or shaft sleeve) made of anti-friction material to open the axial oil groove to distribute lubricating oil lubrication
2) Matching bearing: This kind of bearing is very convenient to install and disassemble, and the price is low, and it is widely used mechanically. For example, bearings on cranks of various types of internal combustion engines
3) Four-part bearing: also known as four-part bearing, which is used in large automobiles, such as vibration engines, vibration engines and other spindle bearings.
The materials of plain bearings are mostly cast iron and cast steel. Because of the hard texture, it is easy to cause journal wear, so a bushing is usually added between the shaft and the bearing. The materials of this bushing are mainly bronze, white alloy and barbit alloy.
2. Sliding thrust bearing
The load of the plain thrust bearing is parallel to the axial direction, which not only supports the rotation of the mechanism, but also prevents movement along the axis. It can be divided into four types:
1) Ring thrust bearing: it is divided into:
(1) Single-ring thrust bearing: Single-ring thrust bearing, which can withstand axial thrust in both directions.
(2) Multi-ring thrust bearing: This kind of shaft can bear axial thrust in both directions, high speed and heavy load.
2) Class bearing: also known as pivot bearing, is a sliding thrust bearing installed at the end of the shaft, so it is also called a base column thrust bearing.
3) Hydrodynamic lubrication thrust bearing: the friction surface between the shaft and the bearing is made into an inclined surface or a tiltable block. A layer of hydrodynamic oil is formed on each inclined surface or tilting block so that the shaft does not come into contact with the bearing
4) Hydrostatic bearing: When the unit load of the bearing is too large, it is impossible to establish the oil film by static starting, so the hydrostatic bearing must be used. The fluid (oil) is pressurized by the pump and sent between the two parts to maintain lubrication during operation. Because the fluid is supplied by the outside world, it is also called an external pressure bearing. If the pump oil pressure is changed to air pressure, it is called a hydrostatic air bearing.
3. Special sliding bearings
1) Porous bearing: also known as oil-impregnated bearing, it is cracked by powder metallurgy cracking method. It is generally suitable for radial bearings with light loads.
2) Oil-free bearings: with excellent wear resistance, suitable for light load and non-polluting food processing machinery, such as Nelong bearings.
Post time: May-15-2025
