Overview
Slip the bearing sliding bearing ,Bearing working under sliding friction. Slip the bearing and work steadily, reliably and having no noise. Under the lubricated condition of the liquid, slipping the surface is separated by the lubricating oil without keeping in touch directly, can also reduce friction loss and surface to abrade greatly, the oil film also has certain sucking and shaking ability. But start and rub resistance bigger. The part that the axle is supported by the bearing is called the journal, the part matching journal is called axle bush. In order to improve the friction properties on the surface of axle bush but the antifrictional material layer of the casting is called the bearing to line with on the surface in it. The material that axle bush and bearing line with is referred to as slipping the bearing material. The commonly used sliding bearing material has alloy of bearing ‘ Also call Palestine alloy or white alloy , wear-resisting casting iron, copper base and aluminium base alloy, powder metallurgy material, plastics, rubber, hardwood and carbon – graphite, politef Special Fluorine dragon, PTFE , modified polyformaldehyde POM , when.
Slip the bearing and employ the occasion generally under the low-speed heavily loaded operating mode condition, or safeguard maintaining and operation position with the note with difficult lubricating oil.
Principle
Can be divided according to the operation principle of the bearing: Rolling friction bearing Rolling bearing With the sliding friction bearing ‘ Slip the bearing .
Slip the bearing: Slip the intersection of bearing and surface, can form, lubricate membrane take exercises vice surface separate, slip frictional force, can reduce greatly, because sport vice surface does not keep in touch directly, so has avoided abrading. The bearing capacity of slipping the bearing is large, it is high to turn the precision round, lubricate the membrane and resist and strike function, so, find extensive application on the project.
The forming which lubricates the membrane is to slip the primary condition that the bearing can work normally, influence the factor of lubricating the film and taking shape to have lubricated way, speed of vice relative motion of movement, physical property of the lubricant and roughness of vice surface of sport,etc.. Should slip the design of the bearing according to the condition of work of the bearing, confirm the structure type of the bearing, is chosen lubricant and lubricated method and confirms the geometirc parameter of the bearing.
Classification
It is numerous to slip the bearing kind.
According to be able to bear the loaded direction, can be divided a radial into ‘ To heart Slip bearing and thrust ‘ Axial Slip two kinds of bearings.
Can be divided into oil lubricated bearing, lipoprotein lubricated bearing, water lubricated bearing, gas bearing, solid lubricated bearing, 7 kinds magnetic fluid bearings and electromagnetic bearings according to lubricant kind.
Can be divided into two kinds membrane lubricated bearing and lubricated bearing of thick membrane according to lubricating the membrane thickness.
Can be divided into a bronze bearing according to the axle bush material, casting iron bearing, plastic bearing, gem bearing, powder metallurgy bearing, from the lubricated bearing and sucking the oil bearing,etc..
Can divide into round bearing, oval bearing, three the intersection of oil and the intersection of leaf and bearing, bearing the ladder, can incline the intersection of tile and bearing and the intersection of foil and bearing,etc. according to the intersection of axle bush and structure.
Structure
It is numerous to slip the bearing kind.
According to be able to bear the loaded direction, can be divided a radial into ‘ To heart Slip bearing and thrust ‘ Axial Slip two kinds of bearings.
Can be divided into oil lubricated bearing, lipoprotein lubricated bearing, water lubricated bearing, gas bearing, solid lubricated bearing, 7 kinds magnetic fluid bearings and electromagnetic bearings according to lubricant kind.
Can be divided into two kinds membrane lubricated bearing and lubricated bearing of thick membrane according to lubricating the membrane thickness.
Can be divided into a bronze bearing according to the axle bush material, casting iron bearing, plastic bearing, gem bearing, powder metallurgy bearing, from the lubricated bearing and sucking the oil bearing,etc..
Can divide into round bearing, oval bearing, three the intersection of oil and the intersection of leaf and axle, bearing the ladder, can incline the intersection of tile and bearing and the intersection of foil and bearing,etc. according to the intersection of axle bush and structure.
Material
Metal material, such as bearing alloy, bronze, aluminium base alloy, zinc base alloy,etc.;
Porous the intersection of quality and metal material ‘ Powder metallurgy material ;
Nonmetallic material.
Among them:
The alloy of bearing: The alloy of bearing is also called white alloy, it is mainly tin, lead, antimony or other metal alloy, because its getting wear-resisting and good and plasticity high, run, shut of good performance and heat conductivity it resists glue and sex to be kind and absorption of oil fine, so applicable in the event that heavily loaded, high-speed, the intensity of the alloy of bearing is relatively small, the price is relatively expensive, must build on axle bush with or the casting iron of bronze, steel while using, form the thinner coating.
The metal material of porous quality: Porous quality one the intersection of powder and material in metal, it is porous to organize for it to have, if soak it in the lubricating oil, full of lubricating oil in the capillary, turn into and suck the oil bearing, have it from lubricated performance. The toughness of the metal material of porous quality is small, only suit in the event that the steady one has not assaulted load and medium and small speed.
Bearing plastics: The commonly used bearing plastics are phenol aldehyde plastics, nylon, politef,etc., the plastic bearing has greater compression strength and wearability, can lubricate with the oil and water, also have it from lubricated performance, but heat conductivity is bad.
Trouble
Slip the bearing while working because the contact with axle bush of the journal will produce friction, cause surface generate heat, abrade even” Kill ” ,So while designing the bearing, should select the antifriction good sliding bearing material for use and make axle bush, choose appropriate lubricant and adopt the appropriate supply method and improve the structure of the bearing to lubricate etc. in order to get thick membrane.
, tiling corrosion: Spectral analysis finds coloured metallic element is unusual in density; The inferior mm levels of a lot of nonferrous metals compositions appear to abrade the particle in the iron table; Lubricating oil moisture exceed standard and acid value exceed standard.
, journal surface corrosion: Spectral analysis finds the iron element is unusual in density, there is one submicron of particles of a lot of iron compositions in the iron table, lubricating oil moisture exceed standard and acid value exceed standard.
, it is strained that the journal is superficial: There is cutting grit or black oxide particle of iron department, the existence flash back color of metal surface in the iron table.
, tile give a piggyback a little work up and abrade: Spectral analysis finds the iron density is unusual, there are a lot of iron composition submicrons that abrade the particle in the iron table, lubricating oil moisture and acid value are unusual.
, it is strained that the bearing is superficial: Find in the iron table that cuts the grit, the grit composition is the nonferrous metals.
, tiling peels off: Iron find, have a lot of tired to peel off alloy abrade particle, the intersection of layer and the intersection of form and grit the large size in the table.
, bearing fever tile: There are more larger alloy grit and ferrous metal oxide in the iron table.
Characteristic
Main installation to slip bearing axle bush in position, power plant large-scale to transfer whom apparatus use mostly slip the bearing, generally speaking axle bush adopts Palestine the alloy is made, so axle bush softens and clicks, melts some are all lower, it is very large too with the contact area of the axle, it is very good to bear the weight of heavier load, damped performance too, can bear greater impact load, if the lubricating oil stores and needs the drive that the oil went bad when being in the underpart of axle bush, to guarantee the forming of the tiling oil film. Generally speaking stipulate the temperature of the rolling bearing can not exceed the 80 ℃ one, and the one that slipped the bearing should be a little lower, the temperature can not exceed the 70 ℃ one.
Design attentive matters
It is a one that keeps in touch to slip the bearing, being exposed to the surfaces should keep certain oil film, so should pay attention to following these question while designing:
, take, enable oil film, enter, rub surface smoothly.
, the oil should be from bearing the weight of the surface district to enter the bearing.
, don’t make the whole the intersection of ring and oil groove turn on in the middle part of the bearing.
, like the oil tile, the seam opened the oil ditch.
, want, make oil ring give oil to be fully reliable.
, the filler hole don’t be stopped up.
, don’t form the oil and does not flow ing area.
, the sharp sides and raised angles that prevent cutting off the oil film.
Damage the form
The sliding bearing used on engine is usually divided into two kinds: One kind is lined with the tile type thin wall bearing, it is commonly called as axle bush to similar to tiles; Another kind is set, also called the copper set, the shape is a hollow round cylinder. Line with the tile type thin wall bearing and is used mainly for supporting the bent axles and connecting rods of the engine; The bushing is used mainly for supporting journal of the camshaft and piston to sell. Now what we mainly understood is lining with the tile type thin wall bearing axle bush Form and precautionary measures damaged in early days.
Form damaged in early days
The bearing in using the course normally, because abrade until losing ability to work, finishing its service life finally gradually, it is different to avoid that this kind is damaged naturally. But if because engine assemble adjust improper and lubricating oil quality fine or the intersection of service condition and factor such as being abominable cause the bearing to abrade or present various damage too early, it is the damage in early days caused artificially. Damage the service life when reduces the bearing not only greatly in early days, but also will influence the normal work of the engine at the same time.
According to finding to the experience of maintenance of diesel engine, have machinery that is damaged to slip the common form in which the bearing damages in early period, lost, lost, corroded etc. a bit more tiredly in the bearing cave for a long time.
It means the surface of alloy of axle bush presents the ditch mark at various degrees that machinery damages and slips the bearing machinery and damages, exposed to the surface to strip and the scratching in a jumble of large area appears when being serious; Generally speaking, are exposed to the surface to damage and exist with the ablation phenomenon at the same time. Lead to the fact the main reason why the bearing machinery damages is that a surface of the bearing is difficult to form the oil film or oil film and is destroyed seriously.
The bearing cave loses Slip the bearing and assault the load at the air cylinder pressure Act on repeatedly under,last plasticity surface layer out of shape and harden cold-working, last abilities out of shape part, form the line progressively and expand constantly, then with rubing the pull-away of the bits, is being formed the cave by the year surface floor. When general axle bush loses, appear in the dent first, then this kind of dent expands and causes the fracture of the alloy-layer interface progressively, the crackle is expanded along the parallel direction of the interface, until peel off. It slips the intersection of bearing and main reason that cave lose to be, because oil groove and the intersection of oil and the intersection of hole,etc. and structural cross section of key element change, cause oil shed strong disorder suddenly, the vacuum district where disorder flows in the oil forms the bubble, because the pressure rises subsequently, the bubble crumbled and fell and produced the cave and lost. Cave lose, take place high year district in bearing generally, the intersection of bent axle and main bearing down at axle bush for instance.
Tired some lose bearing to be tired to lose, mean a bit, because the engine works overloadingly, make bearing work overheated and bearing interval too big, it causes to be tired to damage, not tired to lose or not tired to loss a bit in the middle part of the bearing. This kind of damage mostly overload, the bearing interval is too big, or the lubricating oil is mixed with due to foreign matter uncleanly and inside. So, should pay attention to preventing the overladen work of the bearing from being in order to cross the low or too high rotational speed to operate while using; Adjust the engine to the steady state at the time of the idle speed; Guarantee the normal bearing interval, prevent the engine rotational speed from being too high or too low; Check, adjust the working condition of the cooling system, guarantee the working temperature of the engine is suitable.
It is generally impure for lubricating oil in the district that the alloy of bearing corrodes the alloy of bearing and corrodes, chemical impurity acid oxide,etc. in the platform in the lubricating oil Make the alloy of bearing oxidize and produce the acid material, cause the alloy part of the bearing to loss, form disorder and smallly and split in the hole or small dent. The main reason of alloy corrosion of the bearing is that the lubricating oil selects the improper, bearing material for use and is able to bear corrosivity badly, or the working rudeness of the engine, temperature are too higher.
Bearing cook melt journal, rub against bearing between pack having small protruding metal coverings keep in touch directly, form some high temperature, under lubricating insufficiently, cooling the bad situation, make the alloy of bearing turn black or the part is burnt and melted. This trouble often cooperates with bearing due to high strung for the journal; The lubricating oil is insufficient and apt to make the bearing burnt too in pressure.
Bearing leave round bearing walk outside round to have, rotate relatively in the hole present of the bearing outside. Bearing leave after the exterior round, influence heat abstraction of bearing not merely, apt to make the intersection of bearing and inner the intersection of surface and alloy ablate, and will make the back of the bearing damage, burn the bearing when being serious. Its main reason is, it doesn’t accord with the norm etc. that the bearing passes short, tenon damaging, processing or installation.
Precautionary measures
Slip the bearing and damage and burn more common than the bearing in early period, so prevent from slipping the bearing and damage the importance very in early period. Correct maintenance to slip bearing to reduce effective way that bearing damaged in early period, also lengthen the reliable assurance of bearing life-span. So, the regular maintenance in the engine, with maintaining China, nusual or half a sign abraded appears if the surface of alloy, the back, end head and appearance shape in the edge raised angle of the bearing are unusual or half a sign abraded appears i, will find out the reason conscientiously, and will take the corresponding measure and improve the condition of work of the bearing, pay attention to it to slipping the prevention that the bearing damages in early period.
While improving design and manufacture technological design of the bearing or selecting the bearing for use, should consider the thermal balance of the bearing is in order to control Wen Sheng. Because the bearing works in rubing state, because the liquid internal friction stickness of lubricating oil Cause consumption, transform into behind the heat causing bearing to be warm to rise, lubricating oil viscosity reduce and interval change, will make the bar alloy of the bearing soften, will produce when being serious ” Burn tiles and embrace the axle ” Accident. So, on the structural design, want axle bush not bearing the weight of area on the bearing The top is driven into the oil hole, make the lubricating oil introduce from the not bearing the weight of area; Regard entering the oil hole as the centre on the inner surface of axle bush along turning on the oil groove longitudinally and horizontally, benefit lubricating oil uniform distribution on the journal in order to control Wen Sheng. According to the working condition of the bearing, require the bearing material to possess the following performance: The coefficient of friction is small; Heat conductivity is good, the hot coefficient of expansion is small; Wear-resisting, anti-corrosion and the ability to resist veneer is strong; There should be enough mechanical intensity and plasticity. So, the material available bar alloy of axle bush. Bar alloy can work well at stable load, but very much incident to cavitate under unstable load, so is unsuitable to adopt in the high-power engine. High tin lead base alloy and intensity and hardness of the low tin lead base alloy are relatively high, resist tired resisting, cavitating ability to be relatively better, the result of use is better in the engine of high-power. In recent years, appear, deposit, spatter, plate law, plate, cover the aluminium alloy including 20% tin or plate pure tin at the intersection of copper and the intersection of lead and the intersection of bearing and the intersection of surface and the intersection of nickel and bar with physical gaseous phase abroad, very effective. In addition, change whole round oil groove axle bush into a semicircle oil groove or some oil groove axle bushes, not only can improve the lubricated state that the engine slip the bearing like this but also can improve its bearing capacity.
Improve maintenance and assembly quality of the bearing and improve the cutting with scissors and mixing quality of the bearing, guarantee it has no spot that the back of the bearing is smooth, orient a bit more protrudingly and intact; One’s own opening amount of ball is as 0.5-1.5mm, this can guarantee axle bush is laminated closely through one’s own elasticity and bearing stand hole after assembling; Every end of upper and lower two axle bushes installed in the bearing seat should be higher than the seat level 30-501μ m of bearing, the higher thanning amount can guarantee to tighten the bearing to cover on the bolt rear bearing and cooperate closely with bearing seat according to the fixed torsion, produce enough friction from lock strength, the bearing is unlikely to become flexible, it is effectual to dispel the heat, prevent the bearing from ablating and abrading; Working range of bearing can’t with blow, mix law up to 75%-85% keep in touch the impression and act as criterion, should make bearing and cooperation interval of journal meet the qualification when the scraping. In addition, should notice that checks processing quality of journal and bearing of the bent axle while assembling, carry out the repair craft norm strictly, prevent the torsion of causing and installing because of packing into the method improperly and bearing bolt is uneven or not in accordance with regulation, thus the bending out of shape produces and with centralized stress, lead to the fact the bearing to be damaged in early period.
Select the lubricating oil that the lubricating oil should be selected the oil film with small surface tension for use in the course of using for use and annotate rationally, the impact function that the oil flows is reduced correspondingly, can prevent the bearing cave from losing effectively while making the bubble formed crumble and fall; The viscosity grade of the lubricating oil can’t increase at will, so as not to increase the pyrogenic inclination of the bearing; Must be in the standard range the lubricating oil oil of the engine, lubricating oil and refueling and must be cleaned with the tool, prevent the entry of any filth and water, guarantee the sealed result of every one of engine at the same time. Pay attention to checking and changing the lubricating oil regularly; The place with lubricating oil of note should be pollution-free, there is no sand blown by the wind, prevent the invasion of all pollutant; Different quality, different viscosity grade and different lubricating oil which use the type forbid using with, the sediment time before the lubricating oil is annotated should seldom be less than 48h.
While using and maintaining and maintaining the engine and installing the bearing correctly, should scribble on the surface of sport of axle and bearing in order to stipulate the clean engine oil of the trade mark. After the bearing of the engine is installed and replied, should close the fuel switch first before starting for the first time, drive the engine to dally several times with the starter, put through, open the fuel switch again after mobilizing engine oil and pressing tables to reveal, and the low-speed location, start the engine to operate and observe while putting the throttle. Operating idly for time rapidly can’t exceed 5min. Do the new machine well and overhaul the break-in of period of break-in of rear engine to operate, forbid working under the circumstances that load increase sharply reducing suddenly and high-speed state for a long time in break-in period; It is for a long time full-load work, for engine to finish, can’t shut down at once, must let engine with turn round behind the 15min shutting down at a low speed in the empty load, otherwise internal heat can not break up. Strengthen cleaning and maintenance work of the engine oil filter, crankcase ventilating device, change and strain the core in time according to the manual requirement; Guarantee the engine cools the department and works normally, controls the normal temperature of the good engine, prevent the radiator ” Boil ” ,Forbid not adding the cooling water to drive a vehicle; Select the fuel for use correctly, adjust while mixing the angry phase place and lighting a fire,etc. accurately, prevent the engine from being abnormal and burn; Do inspection and adjustment of the bent axle and technological state of the bearing well in time.
Installation procedure
Basic demand
Should make journal with even and close to keep in touch to slip bearing, have certain the intersection of cooperation and interval also.
Exposed to the angle
Refer to the journal and right central angle of contact surface to slip bearing. It exposed to angles to be can’t can’t too little either. Exposed to angle, will make it increase not to slip the intersection of bearing and pressure while being too light, will make it produce greater deformation not to slip bearing when being serious, abrade with higher speed, shorten service life; Exposed to the angle too largely, will influence the forming of the oil film, can not get the good liquid.
Experimental study shows, it is 120 degrees to slip the limit that the bearing is exposed to the angle. When slipping the bearing to abrade to angle of this contact, the liquid is lubricated and destroyed soon. Influence, slip bearing, pigeonhole under the prerequisite of terms, contact horn to be light and kind. Analyze from the theory which rubs the force moment, when exposed to the angle as 60 degrees, it is minimum to rub the moment, so propose, higher than the sliding bearing of 500r/min to the rotational speed, contacts the angle and adopts 60 degrees, rotational speed is lower than the sliding bearing of 500r/min, being exposed to the angle can adopt 90 degrees, can adopt 60 degrees too.
Contact some
Journal and slipping the actual contact situation of the surface of the bearing, can express through the way that the actual contact on of the unit area count. Keep in touch some more, not thin even, show, slip bearing, blow, grind well, on the contrary, show and slip the bearing that shaves the fault ground. Get on very well, keep in touch some close and many, blow, grind difficulty to be even loud generally. Should be according to slipping the performance of the bearing and condition of work to confirm that contact some in production, the listed materials of table below are suitable for consulting: Slip the bearing rotational speed r/min Contact some the contact on every area of 25* 25 millimetres counts 3~5 under 100 100~500 10~15 500~1000 15~20 More than 1000~2000 20~25 2000 more than 25 Can last table data grade and the machineries of Ⅱ grade precision,grades of the machineries of precision can according to at table data is reduce by half.
