What is the friction between the shaft and sleeve of the sliding bearing?
Sliding friction.But sliding friction is divided into four kinds:1, complete liquid frictionThe complete liquid friction state is that the two surface of the relative sliding in the plain bearing is completely separated by the lubricating oil film, and the oil film has enough thickness to eliminate the direct contact between the two friction surfaces. At this point, there is only friction between the liquid molecules, so the friction coefficient is very small (f =0.001 to 0.008), which significantly reduces friction and wear.2, solid lubrication frictionAt present, a variety of solid lubricant materials are mature and used. In some special conditions, solid lubricants instead of liquid or lipid lubricants. Such sliding bearings are solid lubrication bearings, manufactured by Jiaxing solid bearing company. Similar to the principle of liquid lubrication: the two surface of the relative sliding in the plain bearing is completely separated by the solid lubricating film, and the lubricating film has enough thickness to eliminate the direct contact between the two frictional surfaces. The friction coefficient is higher than that of the full liquid, but the bearing capacity is high, the stability of the lubricant film and the high temperature resistance are better than the liquid friction.
4, dry frictionTwo friction between surfaces without any substance is called dry friction, and in practice there is no ideal dry friction. Because there is always a variety of oxide film on any metal surface, it is difficult to have pure metal contact (unless it is possible in a clean laboratory). Because of the dry friction state, a great deal of friction loss and serious wear will occur, so the dry friction state is not allowed in the sliding bearing, otherwise it will lead to a great temperature rise and burn the bush.Full liquid friction is the ideal condition for sliding bearings. For those important and high speed rotating machines, it is necessary to ensure that the bearings work under full liquid friction, which is often referred to as a liquid friction sliding bearing. The boundary friction often coexists with the half fluid friction state and the semi dry friction state, which is generally called non liquid friction state. Solid lubrication friction is the effective way to replace liquid friction at high temperature and under water, overloading and other special conditions; for those in the low speed and the impact of work under the conditions of the less important machine can press liquid friction bearing design, called non liquid friction sliding bearing.
3, boundary frictionWhen the two relative to the sliding surface of the sliding bearing lubrication exists, the adsorption effect of lubricating oil and the friction surface, the boundary film a very thin layer formed on the friction surface, it can withstand high pressure without damage. The boundary of oil film thickness is smaller than a micron, not enough to bring the two friction surfaces are separated, so the relative sliding friction surface, two micro spike will meet the oil film cut, the formation of direct contact with local metal, so this state is called the boundary friction. In general, the boundary oil film covers most of the friction surface. Although it can not completely eliminate the direct contact between two friction surfaces as completely liquid friction, it can play a role in reducing wear and tear. The friction coefficient of this state is f =0.008 to 0.01.
