18.104.22.168. Radical and шатунные bearings
Kinds of deterioration radical and шатунных bearings
A.Tsarapiny because of hit of the dirt introduced in a material of a covering
V.Nedostatochnaja greasing, a local wipe of a covering of the bearing
S.Nepravilnaja installation of bearings, the brilliant (polished) sites
||D. Конусность necks, a wipe of a covering of the bearing from all surface on length of the bearing
E. Fillet formation on a bearing edge
F. Fatigue deterioration, formation of craters or pockets
In spite of the fact that radical and шатунные bearings at engine major repairs are subject to the obligatory replacement, the bearings which were in operation should be stored in a place of their installation for careful check as wear tracks on these details allow to restore the general condition of the engine. Loose leaves of bearings are subdivided into dimensional groups on a thickness, the accessory to each dimensional group is specified by the colour marks put on the loose leaf.
Sources of rupture of bearings of a cranked shaft are insufficient greasing, presence of a dirt and extraneous particles, an overload of the engine and corrosion. Irrespective of the reason which have caused destruction of bearings, it should be eliminated before definitive assemblage of the engine to avoid repeated damages of these details.
At check of a condition of bearings they should be got from the block of cylinders, covers of radical bearings of a cranked shaft, шатунных covers and rods. Lay out loose leaves on a pure surface in the same order in which they have been established on the engine. It will allow to establish a corresponding support of a cranked shaft in which the bearing has undergone to the strengthened deterioration. At check it is not supposed прикасание by fingers to a working surface of loose leaves not to put on them additional damages.
The dirt and extraneous particles get to the engine for various reasons - in the course of assemblage, through filters or ventilation system картера. Pollution can get also to oil, and from it – in bearings. Frequently at pollution there are metal particles from machining of details of the engine, or owing to deterioration at normal work of the engine. Sometimes at pollution there are rests of abrasive materials after carrying out притирочных and grinding works, especially at insufficient washing and procleaning of the engine after their termination. Irrespective of the origin reason extraneous pollution usually take root into a soft alloy of the bearing and are easily distinguishable. Large particles cannot take root into the bearing and lead to occurrence of scratches and задиров on surfaces as bearing and necks коленвала. The best way of the prevention of such deterioration is careful washing of details and maintenance of faultless cleanliness at engine assemblage. For the prevention of premature deterioration also it is recommended to a thicket to change oil and filters.
Insufficient greasing of the engine ("oil starvation") can be caused variety of the interconnected reasons. Overloads concern them (cause expression of oil from a surface of bearings) and pressure decrease because of leak (emission) of oil (because of the raised backlashes in bearings, deterioration of the oil pump, the big frequency of rotation of a cranked shaft) an engine overheat (causes разжижение oils). The reason of the accelerated deterioration of bearings of a cranked shaft also is blocking of oil channels, usually owing to несовмещенности lubricant apertures in bearings коленвала with apertures in the block of cylinders and in rods that causes insufficient greasing and an exit from bearings out of operation. When a source of rupture is insufficient greasing, there is a wipe or expression of a material of a covering of the bearing from a steel basis. The temperature increases to such level that from an overheat occurs выкрашивание a steel basis of the bearing which gets a bluish shade.
The durability of bearings of a cranked shaft also essentially depends on skills of driving. Bearings test the raised loadings at movement with completely open throttle заслонкой, or with small speed on the raised transfer (in the heavy engine modes). At the raised loadings there is an expression of an oil film. Bearings test изгибные deformations at which microcracks (fatigue deterioration) are formed. As a rule there is a separation of a covering of the bearing from a steel basis in the form of small particles.
Trips on small distances can be at the bottom of corrosion deterioration of bearings as because of insufficient warming up the moisture and the gases causing corrosion have not time to leave сконденсированная. These components collect in oil, causing formation of acids and insoluble deposits. In process of oil receipt to bearings there is a corrosion under the influence of acids, causing destruction of bearings and their exit out of operation.
Wrong installation of bearings at assemblage also leads to their premature deterioration. If the backlash in bearings is less than norm their greasing is complicated that leads to deterioration as well as owing to "oil to starvation". The dirt or the small particles which have got under the loose leaf of the bearing, lead to a local raising of the loose leaf and to the strengthened deterioration in this part.
At assemblage do not touch with fingers loose leaf surfaces, otherwise it is possible to scratch a surface or to bring on the loose leaf of a particle of a dirt.
As it was already marked, at major repairs of the engine loose leaves radical and шатунных bearings are subject to obligatory replacement. Neglect this rule and economy on repair lead to the extremely undesirable consequences.