Sliding bearing preventive measures

Sliding bearing early damage is more common than bearing burning, so to prevent sliding bearing early damage is very important.The correct maintenance of the sliding bearing is an effective way to reduce early bearing damage, is also the reliable guarantee for extend bearing life.Therefore, in the daily maintenance and repair of the engine, must pay attention to the bearing surface of the alloy, the back end and the appearance of edge angles in shape, if there is any abnormal or half signs of wear and tear, to seriously investigate the cause, and take appropriate measures to improve the bearing of the working conditions, pay much attention to the prevention of early damage of the sliding bearing.
(1) improve the bearing design and manufacturing process design or selection of bearings, want to consider the heat balance to control the temperature rise of bearing.Because work bearing under friction condition, caused by oil liquid internal friction (viscosity), power consumption is converted into heat caused by temperature rise, change, lubricating oil viscosity reduction, clearance will soften the babbitt bearing, serious when produce "hold shaft tile burning accident".On structure design, therefore, should from the bearing bush (non load-bearing area) at the top of the oil hole in, make the lubricating oil from the bearing area introduction;Within the bearing surface of the oil hole centered along the longitudinal or transverse groove, conducive to uniform distribution of lubricating oil on the shaft neck to control the temperature.According to the requirements of the bearing working condition, bearing materials must have the following properties: small friction coefficient;Good thermal conductivity, thermal expansion coefficient;Wear-resisting, corrosion resistance and bonding ability;To have enough mechanical strength and plasticity.Therefore, optional babbitt bearing materials.Babbitt can work well in stable load, but under the unsteady load easily happened cavitation, so should not be used in high power engine.High tin lead alloy and low tin lead alloy with high strength and hardness, fatigue resistance and cavitation resistance is stronger, it is better to use in the high power engine.Appeared in recent years, foreign by physical vapor deposition coating method in copper lead bearing surface nickel plating on the grid containing 20% sn or pure tin plating of aluminum alloy, the effect is very good.In addition, the entire round groove bearings instead of semicircle groove or part of the oil groove bearings, such not only can improve the engine sliding bearing lubrication state, but also improve its carrying capacity.
(2) increase the maintenance and assembly quality improvement of bearing bearing hinge with quality, to ensure smooth and no spots on the back of the bearing, positioning bumps intact;Amount of bounce off its 0.5 1.5 mm, this guarantees that after assembly bearing with the aid of its elasticity and bearing hole joint closely;In bearing in the upper and lower two pieces of each end bearing shall be higher than that of bearing seat plane 30-501 microns, the higher quantity can ensure torque tighten bearing cap bolts by the regulation after the bearing and the bearing seat close coordination, generate enough force of friction self-locking, bearing is not loose, good heat dissipation effect, prevent bearing ablation and wear;Bearing of the working face can't scrape contact pattern match method reached 75% - 75% for measure, should be not scraping makes fitting clearance of bearing and shaft neck up to par.In addition, to pay attention to check the crankshaft journal and bearing assembly processing quality, the strict repair technology standard, prevent the installation is not straight caused by improper loading method and uneven bearing bolt torque or do not conform to the regulations, resulting in a bending deformation and the stress concentration, lead to early damage of the bearing.