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  • Imported bearing retainer, sealing ring

    Imported bearing retainer, sealing ring, dustproof cover characteristics.
    Imported bearing retainer, sealing ring, dustproof cover characteristics is introduced:
    retainer
    Steel plate crown type bearing retainer
    According to the inner ring to carry on the design, to the stainless steel plate a stamping forming.
    Nylon crown type bearing retainer
    According to the inner ring design, by polyamide (nylon 66) is made.
    Steel rivet wave type bearing retainer
    The wave form of the two parts by rivet fixed, used in high load operation of the bearing.
    Dust cover
    ZZ: ring type steel bearing dust cover
    Miniature bearing, stamping processing metal plate spring ring fixed in the outer structure.
    ZZ: ram steel bearing dust cover
    Reduce grease exudation, stamping processing with the metal plate reinforcement on the outer race structure.
    seal
    TT: ring type teflon bearing ring
    Mainly used in miniature bearing, join glass fiber teflon ring spring ring fixed in the outer structure.
    2 rs: contact rubber bearing ring
    Effective prevent external foreign invasion, rubber sealing ring embedded bearing ring, ring and inner ring touch.
     

    【2016-06-27】
  • Bearing premature failure of metallographic analysis

    DUF bearing in the job, as a result of a variety of complex reasons, such as the structure unreasonable, the material quality is poor, poor performance, work on the surface defects, shock, vibration, improper installation and bad lubrication etc, all can cause bearing early failure. However, in some cases, some bearing was not put into use (run), but users in machine process the original complete appearance is often damaged, lost the applicability, cause bearing premature failure. This paper tries to reveal is belong to the failure form of a practical example.

    One, failure background

    A certain power plant in assembly S195 diesel engine gear box, the 6205 deep groove ball bearing inner ring gap or continuously happen break-up (block) phenomenon, in quantity of certain proportion (per gear box four sets). According to the investigation on the spot, this batch of bearing total extreamely (-a ly for 3000 sets, the actual have been loaded with 1000 sets, the remaining 2000 sets for user "was" dare not installed.

    After the verification, gear box axial dimension conforms to the drawing requirements, bearing installed method correctly, is the fixed journeymen finish. The user had unpacking extraction 40 sets of measurement bearing internal and external ring of hardness, and the DZ - 2000 type large magnetic inspection machine testing, the result hardness in 61 ~ 65 HRC range, in line with the JB1255 standard, visual check not found crack. In view of this, in order to beg a split bearing ring, the reason of the site would be damaged bearing return, the conventional physical and chemical test.

    These ring system by box type resistance furnace 840 ~ 860 ℃ heating quenching, 160 ℃ x 2 ~ h low temperature oil tempering treatment.

    Second, the test methods and results

    1. The macroscopic observation

    Figure 1 is installed in the damaged bearing real photos.

    After careful observation physical known:

    (1) in all of the damaged bearing not seen for machine knock and left traces wounded, the ball and cage the spare parts such as intact.

    (2) inner ring raceway of split starting at one side of the center, occupy end diameter 1/2 or 1/4.

    (3) fracture in stretch into inside the second longitudinal straight crack, crack is similar to knife cut, through wall.

    (4) the break-up appearance rugged, but fracture surface smooth level off. No signs of plastic deformation, only a small amount of tearing crack.

    (5) fracture with grey fine grain porcelain shape of brittle fracture.

    2. Acid corrosion test

    Respectively will split inner ring with complete inner ring with the 1-1 hydrochloric acid aqueous solution of the thermal pickling, temperature is 60 ~ 70 ℃, time 10 min, the results shown in figure 2.

    (1) in the break-up place nearby raceway exist inside banded grinding burn and grinding cracks.

    (2) grinding cracks are dendritic, along the raceway side distribution, and with grinding direction parallel, just burst along the grinding crack development.

    (3) secondary longitudinal straight crack and burst fracture and grinding cracks is roughly "T" type vertical.

    (4) the entire ring surface distribution with loose shape black scotoma and pore, its shape is round or oval. In the amplification 40 times the stereoscopic microscope observation, its shape is irregular hole or circular aperture, they can be connected into each other like grain boundary shape, and complete ring surface is quite bright and clean, could not see the above defects.

    3. Apparent hardness and microstructure

    In order to further understand ring of hardness distribution and quenching tempering microstructure and surface of the microstructure feature, and selected parts of the inner ring and burst fragment, in its upper end fixed macroscopic hardness, and linear cutting method in split place near interception longitudinal metallographic specimen, the result is:

    (1) the macro hardness value for 64 ~ 65.2 HRC.

    (2) the organization JB1255 quenching and tempering with standard 3 ~ 4 level, local area up to 5 level, for small crystal martensite + aphanitic martensite ten fine acicular martensite + a small amount of residual carbide + residual austenite.

    (3) in 100 times and observed under martensitic matrix is obviously black and white banded organization, if according to YB9-59 standard can be judged to be 4 level, as shown in figure 3 shows.

    (4) observed raceway surface exist a layer of a crescent shape of the secondary hardening white layer organization and sub-surface of high temperature softening layer organization, namely "after tempering layer". The white layer depth (the surface to link bottom) is about 0.033 ~ 0.056 mm, tempering depth about 0.293 mm, visible grinding burns very serious degree, as shown in figure 4 shows.

    Three, result analysis

    1. The grinding quality on bearing premature failure of the influence from the above test results can be judged, raceway side of the grinding cracks and grinding burn is a cause of ring break-up, cause bearing premature failure of a direct cause, this example reveals macroscopic crack form and grinding burn the distribution characteristics of instructions, raceway of the original position after partial or roller way R not round, one side of the raceway grinding allowance increases, when the coarse grinding feed stage, grinding speed, the whole raceway is produced not uniform grinding. If not timely grinding wheel dressing, will promote grindings embedded or adhesive cause wheel pore jams and passivation, which will cause the grinding wheel unbalance degree high, the spindle vibration increased, even machine vibration and produce grinding flutter. Obviously grinding force occurs cyclical change, form discontinuity burns banding.

    This grinding area rate wipe force and grinding force will inevitably will heighten, produce high grinding heat. When grinding area surface temperature as high as moment or exceed the Acm, raceway local be ground surface will be back austenitizing. The volume expansion, and the low temperature of inner part to restrict its expansion, produce surface compression and lining for expansion of the thermal stress. When the wheel from grinding after surface. In external cooling liquid quenching conditions (even empty cold), the surface has austenitizing thin layer, again carries on the second Cui fire, forming high hardness of the secondary hardening organization, namely "grinding white layer". At the same time because grinding heat inward and its adjacent layer on the penetration of the diffusion effect, it can form a layer of hardness lower black "tempering layer", the volume shrinkage, so in the grinding surface layer is produced in the high temperature gradient, which cause a series of organization change and mechanical properties change. "grinding white layer" system in a pressure stress state, and "tempering layer" is in the largest tensile stress state, so the most easy to crack the core in the initiation, especially "grinding white layer" and "after tempering layer, on the border, because it

     

    【2016-06-27】
  • Bearing the specific classification

    According to the loading direction can be divided into: (1) the radial humanistic bearing, also called radial bearing, bear radial load. (2) the thrust bearing, say again thrust bearing, bear axial load. (3) radial thrust bearing, also called radial thrust bearing, and at the same time, bear radial load and axial load. Work according to the bearing friction properties can be divided into sliding friction bearing (hereinafter referred to as sliding bearing) and rolling friction bearing (hereinafter referred to as rolling bearing) two kinds big.
    Deep groove ball bearing
    The most representative rolling bearing, wide range of USES
    Can bear radial load and two-way axial load
    It is applicable to high-speed rotating and requirements of low noise, low vibration occasions
    With steel plate dust cover or rubber sealing ring seal type Harbin bearing inner advance filling the right amount of grease’s outer ring has anti-rotation ring or flange bearing, namely easy to axial positioning, and convenient for the installation of the enclosure
    Maximum duty bearing size and standard bearing the same, but the inner and outer one place filling tank, increase the loading ball number and improve the rated negative.
    The main applicable cage: steel plate stamping cage (waveform, crown... single row; S shape... double column)
    Copper alloy or phenolic resin cutting cage, synthetic resin forming cage
    Main application: car: rear wheel, gear boxes, electrical installation components
    Electrical: general motor, household electrical appliances
    Other: instrument, internal combustion engine, construction machinery, railway vehicle, loading and unloading handling machinery, agricultural machinery, all kinds of industrial machinery
    Angular contact ball bearing
    Ring and ball between contact Angle, the standard contact Angle is 15 ° and 30 ° and °The greater the Angle of contact axial load capacity is bigger also Contact Angle is smaller, the better the high speed rotating Single row bearing can bear radial load and unilateral axial load DB combination, DF combination and double bearing can bear radial load and two-way axial load DT combination suitable unilateral axial load is bigger, a single bearing rated load shortage situation High speed with ACH type bearing ball diameter small, ball number, mostly used for machine tool spindle Angular contact ball SKF bearing is suitable for high speed and high precision rotary The structure for the combination of the two single row angular contact ball bearing common inner ring and outer race, can bear radial load and two-way axial load No filling tank bearing also have sealed typeThe main applicable cage: steel plate stamping cage (bowl... single row; S form, crown... double column) Copper alloy or phenolic resin cutting cage, synthetic resin forming cage Main application: single row: machine tool spindle, high frequency motor, gas turbine, centrifugal separator, small car wheel, differential pinion shaf Double: oil pump, roots blower, air compressor, all kinds of transmission, fuel injection pump, printing machines Four contact ball FAG bearing can bear radial load and two-way axial load A single bearing can replace positive combination on the back or combination of angular contact ball bearing Applicable to inherit pure axial load or axial load component large synthetic load This kind of bearing bear any direction axial load can form one of the contact Angle (alpha, so ring and ball always in a contact line double dealing point contact The main applicable cage: copper alloy cutting cage Main use: the plane jet engines, gas turbine Self-aligning ball bearing
    Due to the outer raceway hand deliver spherical, with self-aligning properties, so it can automatic adjustment for shaft or shell of deflection or different heart is caused by the axis Cone hole bearing through the use of fasteners can easily installed in shaft Steel plate stamping cage: chrysanthemum form... 12, 13, 22... 2 rs, and... 2 rs Kwai form... 22, 23 Woodworking machinery, textile machinery transmission shaft, vertical set-contained self-aligning bearing Cylindrical roller bearing

    Cylindrical roller and roller way a line contact, radial load capacity, which is designed to withstand heavy loads and shock load, also suitable for high speed rotating N type and NU type can be axial movement, can adapt for thermal expansion or installation error caused by the shaft and housing relative position changes, the most adapt to used for free end bearing NJ type and NF type can bear a certain degree of unilateral axial load, NH type and NUP type can bear a certain degree of two-way axial load inner ring or their cups are separable for easy loading and NNU type and NN type resistance to radial load strong rigidity, mostly used for machine tool spindle
    The main applicable cage: steel plate stamping cage (Z), copper alloy cutting cage, pin type cage, synthetic resin forming cage
    Main application: medium and large motor, generator, internal combustion engines, gas turbine, machine tool spindle, speed reducer, loading and unloading handling machinery, all kinds of industrial machinery
    Entity type needle roller bearing
    Have the basic structure of bearing inner ring and NU type cylindrical roller bearing the same, but because the needle, the volume can be reduced, and can withstand large radial load without inner ring of bearing the has an appropriate precision and hardness of the shaft installation surface as raceway surface use
    The main applicable cage: steel plate stamping cage
    Main application: automobile engine, transmission, pump, excavator crawler wheel, hoist, bridge crane, compressor
    Tapered roller bearing
    This kind of bearing with frustum of a cone shape roller, roller by inside circle big guard guide
    Design makes the inner ring raceway surface and outer raceway surface and roller rolling the each cone vertex intersection in the bearing center online point
    Single row bearing can bear radial load and unilateral axial load, double bearing can bear radial load and two-way axial load
    Applicable to withstand heavy loads and shock load
    According to the contact chest (alpha different, divided into small cone Angle, the cone Angle and the big cone Angle three type, the greater the contact Angle axial load capacity is bigger also
    Outside and internal components (inner ring and roller and cage components) separable, easy to put down
    Rear auxiliary code "J" or "JR" bearing with international compatibility
    This kind of bearing has many use English series products
    The main applicable cage: stamping steel cage, synthetic resin forming cage, pin type cage
    Main application: car: front, rear wheel, transmission and differential pinion shaft. Machine tool spindle, construction machinery, large agricultural machinery, railway vehicle gear reducer, mill roll neck and reduction gear.

     

    【2016-06-27】
  • Off-brand bearing change into famous brand trademar

    Will off-brand bearing change into famous brand trademark, imposing sold to enterprise, to obtain sudden huge profits, that cause great damage to the enterprise. On January 20, weihai in shandong province HuanCuiOu procuratorate to production and sale of fake or substandard products to sin GuoFuGui five suspects approval of arrest according to law, and suggested that the public security organ to continue investigation. In 2001, GuoFuGui in weihai established a mechanical and electrical company, the main sales bearing and mechanical and electrical products in 2005, and set up a production in luoyang bearing company. Due to the famous brand bearing and off-brand bearing price difference is very big, GuoFuGui will seek to distant relative guo road of strong, GuoYongXin do help, and invited one of dong road is responsible for the procurement, in weihai hired LiuJunQuan responsible for sales. They sales bearing part is dong road from all around the purchasing of a less known and inferior brand bearing, part GuoFuGui in luoyang bearing company production of counterfeit products, mostly do not accord with national technology standard. They use fake tool, through the change, trademarks, change the type of way, off-brand bearing after packaging wave body into domestic and international famous brands bearing from January 2009 to November 2010, they will be a large number of fake and inferior bearing are sold to weihai local several well-known enterprises, the sales volume of about 300000 pieces, the sales amount reaches as high as 370 yuan. Since the bearing quality is not standard, for the enterprise production caused serious losses. In view of the case involved huge amount, affects the bad, the procuratorial organs timely intervention investigation link, guiding the public security organ is relevant personnel position, reward, division of labor, etc fixed evidence in time. Handle a case prosecutors after careful reading case, arraignment criminal suspects, to ask the witness that five people involved behavior completely conform to the production and sale of fake or substandard products the components of sin.

     

    【2016-06-27】
  • DUF Bearing Group Year-end summary meeting

    DUF Bearing Group Year-end summary meeting
     

    【2016-06-27】
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