2013年7月15日星期一

Oil spill caused by the bearing ring hair treatment

Bearing due to frequent use, and oil will reduce bearing life, then how do we clear bearing on the oil it? Here to teach you an easy method of clearing the oil on the bearings.
Soft dry oil or rust paste hardened bearing should immersed in 100 ℃ ~ 200 ℃ hot oil, use pliers bearings, bearings with a hair brush oil on a clean. Soft dry oil or rust cream is heated to 100 ℃ ~ 200 ℃ to melt easily washed from the cracks in the bearing out. Sometimes just the bearing in the oil repeatedly shaking. Oil will be flowing away from the gap.
In cleaning bearings, spherical bearings to the heart, it should put the ball, bead frame, the inner from the outer lateral transfer out and then immersed in hot oil, the short cylindrical roller bearing roller cleaning when they should, bead frame, inner and outer disengage.
 (A) the bearing raceway raceway sound and control the sound is running when the bearing, the rolling body raceway rolling issued a slippery continuous sound, all bearing the unique occur basic sound . Sound that is generally bearing raceway sound with other sounds. Ball bearing raceway sound is irregular frequencies above 1000Hz, its main frequency does not change with the speed, but the total sound pressure level increases with the speed acceleration. Raceway sound big INA bearings, the roller with the sound pressure level decreases with increasing viscosity; while the sound of a small roller bearings, and its level increased in viscosity to about 20mm2 / s or more, by reducing the to be increased. Greater rigidity of bearing raceway total sound pressure level is lower. If the radial clearance is too small, the total sound pressure level raceway and the main frequency will decrease as the radial clearance increases dramatically. Control raceway sound methods are: selection of low-noise bearings that waviness small bearings, judicious selection of the conditions of use. Raceway sound often affect the entire mechanical noise reduction raceway sound can reduce the overall mechanical noise.
 (2) the impact of rolling sound and control models of ball bearings or larger cylindrical roller bearings in pure radial load low speed, the centrifugal force due to rolling body is small, in a non-load zone of rolling element will Shock cage or raceway and noisy. However, as the speed increased, the sound will disappear. Impact on the rolling sound control methods are: appropriate to reduce the radial clearance, the use of reasonable structure supple material of the bearing cage.
 (3) bearing jarring sound and control jarring sound is a cylindrical roller bearings on all occasions that may occur harsh sound of metal friction occurs mostly in grease lubricated bearings in larger models, and in the base oil properties more susceptible to deterioration of grease, oil lubrication in almost no time. In addition, more prone to winter, when subjected to pure radial load, radial clearance prone to big occasions, and with models of different sizes, at a particular speed range prone to both occur consecutively will appear intermittently. Outer ring raceway take special processing methods to prevent the emergence of creaking, if necessary, use this bearing, or appropriate to reduce the radial clearance, use grease with excellent performance and increasing the rigidity of the bearing mating parts .

Do need to pay attention to the daily details of bearing maintenance

First, touch
Bearing temperature is often expressed in unusual circumstances. Harmful to the bearing temperature and the lubricating oil. Sometimes, bearing overheating can be attributed to the bearing lubricant and bearing over 125 ℃ temperature in the long run, reduce bearing life, resulting in high bearing the following reasons: lack of lubrication or excessive amount of lubricating oil, lubricating oil containing impurities , heavy duty, bearing damage, lack of space, and seal friction generates heat. Therefore, continuous monitoring bearing temperature is necessary, whether the measure or other important part of the bearing itself. If you are in the business situation has not changed, any change in temperature may be faulty.
Bearing temperature measurement can often help thermometer can accurately measure the temperature of the bearing, and in accordance with degree. Important bearing when it is damaged, it will cause equipment downtime, therefore these bearings should preferably be equipped with a temperature probe. Under normal circumstances, the bearing lubrication and lubricated natural temperature rise and for one day or two.
Second, observe
If you have a good lubrication and bearing right debris and moisture barrier that seals should not wear, but preferably in the open bearing housing to visual inspection and periodic inspection bearing seals, bearing seals around the examination conditions, ensure that sufficient to prevent liquids or corrosive liquids or gases from entering the bearing along the axis. Protection ring and labyrinth seals should be coated with grease to protect its maximum protection. Seals if worn should be replaced soon. Oil sealing function in addition to the bearing to prevent the magazine, and the other function is to keep lubricated bearing housing. If the seal leaks immediately check the seal has been worn or loose oil block. Leak phenomenon may be caused by loose fitting of the bearing box or because adding too much lubricant to form a mixed and leak detection, automatic lubrication system to ensure that the correct amount of lubricant and to examine whether or black, if such a phenomenon, usually say that the lubricant contains magazines.
Third, listen
Using auditory recognition irregular operation is very common approach. For example, with electronic stethoscope to listen to part of the abnormal noise is experienced by method of operation. If it is in good working condition of the bearing will make a low hum of voices. If a sharp hiss, squeaks and other irregular sounds, commonly referred to as the poor working conditions of the bearing. Harsh creaking sound may be due to improper lubrication. Improper bearing clearance may also cause a metallic sound. Dent on the bearing outer ring track will produce vibrations and resulting smooth crisp sound. If the installation of the percussion scars will produce noise, noise will vary with the bearing speed. If there is intermittent noise, rolling element may be damaged. This sound is happening on the surface bearing the date, if the pollutants are often caused by the hissing. Severely damaged bearings will produce irregular and noise.
Bearing damage is listening to consciousness, but usually at this time has come to replace the bearings. Thus, a better way, for example, such as electronic control equipment, diagnostic bearing operating condition.
1: Current bearings are lubricated with grease, running over 1,500 hours, should be timely replacement of grease filling should be noted that the amount of oil required amount, because too little or too much grease will cause the bearing heating, Chong Yu proposed to maintain the amount of fuel in the bearing chamber volume of 1/2 to 2/3 is appropriate.
2: The use of sodium based grease motor bearing (most are of this type), this feature is to grease temperature (125 ℃), drawback is easily dissolved in water, so the lubrication pump is entirely inappropriate.
3: used for holding oil or grease containers should be clean, and usually should be sealed well, do not let dust, iron filings and other debris fell on them, so as to avoid damage to the bearings.
4: Take special note is put into use a new pump for the first time in 100 hours of operation shall be promptly replaced after grease (oil), the next to replace 1 500 hours of operation.
5: For the use of oil-lubricated bearings, the oil should be added to a predetermined position.

Bearing structure types on the different requirements of maintenance

1, thrust bearing angular contact ball bearing
Axial angular contact ball bearing contact angle of 60 ° commonly used general thrust angular contact ball bearings are generally two-way thrust angular contact ball bearings, mainly used for precision machine tool spindle, usually with double row cylindrical roller bearings used in conjunction, can withstand two-way axial to load, with high accuracy, good rigidity, low temperature, high speed, easy assembly and disassembly.
2, bearing deep groove ball bearings
Deep groove ball bearings in the structure of each ring has a cross-section of the equatorial circumference of the ball one-third of the continuous groove type raceway. Deep groove ball bearings are mainly used to bear radial load, but also bear certain axial load. When the bearing radial clearance increases, with the nature of angular contact ball bearings, can withstand both directions alternating axial load. With the same size compared to other types of bearings, such bearings friction, high limiting speed, high precision, user selection is the preferred bearing type. Deep groove ball bearing structure is simple, easy to use, is the largest production volume, most widely used of a class of bearings.
3, the bearing thrust tapered roller bearings
Since thrust tapered roller bearings rolling body is tapered roller, rolling in the structure of the bus and the bus were raceway washers intersect at a point bearing axis line, and thus can form pure rolling rolling surface, high speed limit in thrust cylindrical roller bearings. Features: Thrust tapered roller bearings can withstand a one-way axial load. Thrust tapered roller bearing type code 90000.
4, bearing double row tapered roller bearing structure, performance characteristics
Double row tapered roller bearings range, the maximum amount is 35 000 type, with one pair of outer and two inner ring raceway, there is an interval between the two inner circle, changing the thickness of the spacer adjustable clearance. These bearings radial load at the same time can withstand axial load in the axial bearing clearance range limit axial displacement of shaft and housing. Tapered roller bearing structural features. Tapered roller bearing type code 30000, tapered roller bearings are separable bearings. Tapered roller bearings are mainly used to bear radial load mainly radial and axial joint load. And angular contact ball bearings, bearing capacity, low speed limits. Tapered roller bearings can withstand axial load in one direction, the shaft or housing to limit axial displacement in one direction.
In order to give full play to the bearing and long maintained its proper performance, you must do a good job of regular maintenance (periodic inspection).
By appropriate periodic inspection, so that early detection of failure to prevent accidents in the first place, to improve the productivity and economic importance.
1, cleaning
Remove the bearing inspection, photography and other methods to do first with the appearance of records. In addition, to confirm the remaining amount of lubricant and lubricant samples, and then cleaning bearings.
a, bearing cleaning of rough wash and sperm washing and can be placed in the bottom of the container used metal grid.
b, coarse wash, brush, etc. used in the oil or grease removal adhesive material. At this point if rotating bearings in oil, attention and other damage due to foreign objects rolling surface.
c, sperm washing, in the oil slowly rotating bearings should be carried out carefully.
Commonly used cleaning agents for the neutral water diesel or kerosene, is sometimes necessary to use warm lye. Regardless of what kind of cleaning agent filter should always be kept clean.
Cleaned immediately after anti-rust coating on the bearing grease oil or rust.
2, check with the judge
In order to determine whether the re-use of the removed bearing should focus on checking the accuracy of its size, rotation accuracy, internal clearance and with the surface, raceway, cage and ring.
On the inspection results, may be used to bearing or bearings were judged proficient.
Determine the mechanical properties and the criteria according to the degree of importance and checking cycles vary. If the following injury, the bearings must not be reused and must be replaced.
1) bearing parts breakage and defects.
2) rolling surface raceway material peeling.
Bearing fault identification method
Not by removing checks to identify or predict the bearing in operation without failure, to improve productivity and economy are very important.
The main identification methods are as follows:
1) identified by voice
Identify needs through sound experience. Must be adequately trained to recognize bearing achieve sound and non-bearing sound. To do this, you should try to carry out this work by hand. A listening or listening rods attached to the housing can clearly hear the sound of the bearing.
2) identification of the operating temperature
This method is relatively identification method is limited to use in the operation state is not changing situations. Therefore, the temperature must be continuously recorded. Fails, only the temperature rises, there will be irregular changes.
3) to identify the state of the lubricant
The lubricant sampling and analysis, through its pollution level is mixed with foreign matter or metal powders to judge. This method does not close observation bearings or large bearings are particularly effective.

2013年7月14日星期日

Tapered roller bearing role and use of matters

Tapered roller bearings mainly bear radial diameter and axial joint load. Load bearing capacity depends on the outer ring raceway angle, angle greater carrying capacity. These bearings are separable bearings, rolling bearing according to the number of rows into single row, double row and four row tapered roller bearings. Single row tapered roller bearing clearance to be adjusted during installation the user; double row and four row tapered roller bearing clearance in the factory according to user requirements is given, not to be user adjusted.
Tapered roller bearings have tapered inner and outer ring raceway, Tapered Roller arranged in between. All conical surface projection lines are the same point on the bearing axis together. This design makes tapered roller bearings particularly suitable for combined (radial and axial) loads. Most of the axial load bearing capacity is determined by the contact angle α; α angle increases, the higher the axial load capacity. Angle size calculation factor e; e larger the contact angle the greater the bearing axial load greater applicability.
Tapered roller bearings are usually separated type, namely the belt roller and cage assembly of inner components can be composed with tapered conical outer inner (outer) installed separately.
Tapered roller bearings are widely used in automotive, mill, mining, metallurgy, plastics machinery and other industries.
Tapered roller bearings are devices emerged in the process of scar secondary reason is: the bearing being installed, assembled emerge inner, outer skew; or promise is being installed and the process of assembling the emergence of strikes load bearing emerge eventually forming scar .
Tapered roller bearings are device according to job specifications should stop, should not form many achievements, such as in the form of devices or methods did when, will form the bearing surface of the raceway and Gulu emerged bearing linear scar formation. Deep groove ball bearing unit using indirect response when the bearing precision, life expectancy and functionality.
Tapered Roller Bearings and other aspects of quality are better though, but bearing are precision components, its use should also be carefully carried out. No matter how high-performance bearings, if used improperly, it will not get the expected performance. Note the use of the relevant bearings were the following:
(A) maintain tapered roller bearings and surrounding clean.
    Even the eyes can not see small dust, will give adversely affect the bearings. Therefore, to keep the surrounding clean so that dust will not invade bearings.
(2), exercise extreme caution.
    In the use of tapered roller bearings to give a strong impact, it will have a scar and indentation, cause of the accident. Severe cases, crack, fracture, it must be noted.
(3), using the appropriate operating tool.
    Avoid the existing tools instead, you must use the right tools.
(4), note tapered roller bearing corrosion.
Bearing operation, the hands sweat will become rusty cause. To pay attention to clean hands operation, the best possible wear gloves.
Tapered roller bearings use hearing to identify irregular operation is a very common method, examples such as using electronic stethoscope to check certain parts feel unusual noises are experienced operator. If the bearing is in good operating condition, it emits low whining sound, if a sharp hissing sound tapered roller bearings, squeaky voice and other irregular sounds, usually means bearing in poor operating condition.
1, the tile surface corrosion: spectra showed that the concentration of non-ferrous metal element anomalies; iron spectrum, there were many non-ferrous metal components submicron wear particles; lubricants excessive moisture, acid exceeded.
2, the journal surface strain: iron spectrum in cutting abrasive or black iron oxide particles present on the surface of metal tempering colors.
3, the journal surface corrosion: spectra showed abnormal concentrations of iron, iron spectrum, there are many sub-micron particles of iron content, excessive moisture or oil acid value exceeded.
4, the surface strain: iron spectrum were found to have cutting abrasive, abrasive ingredients ferrous metals.
5, tile back fretting: spectra showed abnormal concentrations of iron, iron spectrum, there are many iron content submicron wear particles, water and oil acid abnormalities.
Lubrication conditions in the liquid, separated from the sliding surface is not in direct contact with oil, but also can greatly reduce the friction loss and surface wear, the film also has a certain vibration absorption capacity
Sharp creaking noise may be due to inadequate lubrication caused. File bearing clearance will cause metallic sound. Tapered roller bearing outer ring dent on the track will cause vibration, resulting in smooth and crisp sound, if caused by the installation of percussion scars will produce noise, this noise will be low as the bearing speed varies. If there are intermittent noise, then the rolling elements may be damaged, tapered roller bearings This sound occurs when the damaged surface is rolling out of date, bearing if contaminants often cause hissing sound, severe bearing damage will irregular and huge noise.
Bearing damage can certainly perceptible by listening to, but usually at this time has come to bearings must not be replaced immediately. Therefore, a better use of such electronic methods such as condition monitoring instruments, tapered roller bearings off the bearing pre-eruptive functioning.

The use of angular contact ball bearings check

Machine shaft parts, especially the spindle, thrust ball bearings are generally assembled into one, and a high rotational speed, and sometimes it will produce very high heat. This phenomenon if not removed, will cause the angular contact ball bearing overheating, and to the corresponding parts of the machine to produce thermal deformation temperature, serious cause spindle and tailstock is not high, which not only affects the accuracy and precision machine itself and would have bearing burn.
Rating fatigue life, refers to a group of the same type of bearing, operating under the same conditions, 90% of the angular contact ball bearing does not appear rolling fatigue spalling of the total number of revolutions. At constant speed, the more the total running time to indicate the nominal fatigue life.
In the research thrust ball bearing life, you can not only consider the fatigue life, but also according to the performance of the bearing should have consolidated several usage limit to consider. For example, greased bearing grease life. Noise life, abrasion life, etc., according to different purposes, using different reference limits, and therefore, most of the experience of pre-selected limits.
Therefore, only the survey angular contact ball bearing damage, injury is difficult to know the real reason. However, if you know the thrust ball bearings using mechanical, conditions of use, bearing the surrounding structure, to understand the situation before and after the accident, combined with state of the bearing damage, and several reasons, we can prevent similar incidents from recurring.
angular contact ball bearing are available judgments, mainly on account of bearing damage, mechanical properties, importance, operating conditions, to be determined during the next overhaul. If you can not use the following defects must be replaced with new thrust ball bearings. The inner ring, outer ring, rolling elements, cage on any cracks or gaps.
Kinds of bearing wear failure is a common failure modes, can generally be divided according to wear the most common form of abrasive wear and adhesive wear.
1 film resistors diagnostic techniques
    Features: for different operating conditions using the same criteria. For flaking, indentation, cracks or other abnormal diagnostic poor results.
    Application: for rotary axes exposed occasions.
2 Vibration diagnostic techniques
    Features: Vibration diagnostic technique widely used; allows online monitoring; diagnosis faster diagnosis theory has matured.
    Applications: especially suitable for rotating machinery angular contact ball bearing fault monitoring.
3 Ferrography diagnostic techniques
    Features: The machine without the disintegration; investment is low, the effect is good; able to find oil-bearing early fatigue failure; do wear mechanism.
    Applications: Suitable for lubricants lubricated angular contact ball bearing fault diagnosis, for grease lubricated bearings more difficult.
4 Temperature diagnostic techniques
    Features: Diagnostic simple; judgment on bearing burn better.
    Applications: Suitable for machine bearing simple routine diagnosis.
5 optical monitoring and diagnosis techniques
    Features: Fiber optic displacement sensor with high sensitivity; directly extract the signal from non-oil bearing surface to improve the signal to noise ratio; may directly reflect the angular contact ball bearing manufacturing quality, surface wear, load, lubrication and clearance situation.
    Applications: For the sensor can be installed in the bearing seat of the machine.
6 acoustic emission diagnostic techniques
    Features: Diagnostic fast, simple; available on-line monitoring.
    Applications: In recent years the development of new technologies, in the bearing condition monitoring is seldom used.
    Direct hands to take non-oil bearing, to fully wash hands sweat, and coated with high-quality mineral oil before, during the rainy season and summer with particular attention to rust. In some special operating conditions, angular contact ball bearings can get a longer life of the conventional calculation, especially in the case of light load. These special operating condition is, when the rolling surface (track and rolling member) by a lubricant film to effectively separate and restrictions may result in contamination of surface damage. In fact, under ideal conditions, the so-called permanent bearing life is possible
    Does not allow a strong punch, does not allow a direct hit with a hammer bearing, does not allow pass through the rolling pressure.
Angular contact ball bearings a rotating inner ring and outer ring raceway, the rolling contact with the rolling body is thus running track for the dark side, running track attached to the roller surface does not belong to an exception, which can be traced load conditions, so removing oil-free bearings, please strict attention and observation raceway running track.

2013年7月10日星期三

Bearing corrosion causes and solutions

Bearing corrosion is very common, it will reduce bearing life. So everyone in their daily work must pay attention to this issue.
High temperature bearing corrosion causes and prevention methods to determine, first look at high-temperature bearing corrosion is caused by what is generally divided into external and internal factors. Summarized:
A metal surface finish (poor oxygen concentration cell corrosion).
2 metal chemical composition and structure of the material itself.
3 solution in contact with the metal surface composition and pH.
4. Ambient temperature and humidity.
5 in contact with the metal surfaces of the various environmental media.
6 different people sweat also lead bearing corrosion reason, it had a pH of 5-6. Therefore, in order to prevent corrosion caused by hand sweat, installation and production personnel should wear gloves, it should not touch the high temperature bearings.
Oiled to prevent rust high temperature bearings:
1 immersion method: some small bearings with high temperature grease soaked in rust, the film thickness can be controlled by anti-rust oil temperature or viscosity to achieve. Adhesion to the surface layer of rust grease approach.
2 brushing method: Brush evenly spread attention when bearing surfaces at high temperatures, do not produce accumulation and pay attention coated to prevent leakage.
3 spray method: Some material not suitable for large-scale anti-rust oil coating by immersion method, generally about 0.7Mpa pressure filter with compressed air spray cleaner place. Spray application of anti-rust oil or solvent dilution thin rust oil. This method must be improved fire protection and labor protection measures.
    Rotates under load bearing inner and outer raceway or rolling a decent due to rolling fatigue showing scaly peeling.
Bearing peeling injury reasons:
1, the load is too large
2, poor installation (non-linear), torque load, foreign invasion, water.
3, poor lubrication, lubricants unsuitable bearing clearance inappropriate.
4, the bearing box accuracy is not good, the rigidity of the bearing box uneven shaft deflection
5, rust, corrosion points, scratches and indentations (surface deformation) caused by the development.
Measures taken to solve bearing peel injury:
1, check the size of the load and re-used for the study of the bearing
2, improved installation methods, to improve the sealing device shutdown rust.
3, using the appropriate viscosity lubricant to improve the lubrication method.
4, check the accuracy of the shaft and bearing housing
5, check the clearance.

Joint bearing characteristics and performance

Joint bearing characteristics and classification
Because the characteristics of joint bearing, so many customers do not understand it's respective sectors. In fact, belong to the sliding bearing joint bearing areas. But why are assigned bearing areas go? The reason is the main producer countries in the world are bearing factory, so the international standardization organizations will also be classified as rolling bearings Technical Committee.
    Joint bearing consists of: sliding contact surface is a spherical surface by a spherical inner ring and an inner spherical surface of the outer ring. Joint bearing is mainly applied to the swing motion, tilt movement and slow rotary motion of the sliding bearing.
    As long as there bearings: Angular contact spherical plain bearings, thrust bearings, spherical plain bearings, stalk end bearings. The classification is primarily bearings can bear loads according to their direction of nominal contact angle and structure type to distinguish.
What are the characteristics of spherical plain bearings
    (1) GE ... E Every single outer ring, no oil tank. Can bear radial load and smaller in either direction axial load.
(2) GE ... ES-type single-slit outer ring, a lubrication groove. Can bear radial load and smaller in either direction axial load.
(3) GE ... ES-2RS type single slit outer ring, with oil tank, sides with a ring. Can bear radial load and smaller in either direction axial load.
(4) GEEW ... ES-2RS type single slit outer ring, with oil tank, sides with a ring. Can bear radial load and smaller in either direction axial load.
(5) GE ... ESN type
Single slit outer ring, a lubrication groove, the outer ring groove. Can bear radial load and smaller in either direction axial load. But by the snap ring axial load to bear, its reduced ability to withstand axial load.
(6) GE ... XSN type
Double slit outer ring (split outer ring), there are oil tank, outer ring groove. Can bear radial load and smaller in either direction axial load. But by the snap ring axial load to bear, its reduced ability to withstand axial load.
(7) GE ... HS-type inner ring with oil tank, double half outer ring, worn clearance can be adjusted. Can bear radial load and smaller in either direction axial load.
(8) GE ... DE1 type
Inner ring of hardened bearing steel, bearing steel outer ring. In the inner extrusion assembly has lubrication groove and hole. Less than 15mm diameter bearings, no lubrication groove and hole. Can bear radial load and smaller in either direction axial load.
(9) GE ... DEM1 type
Inner ring of hardened bearing steel, bearing steel outer ring. In the inner extrusion assembly, bearing into the bearing after the end of the groove on the outer ring of the bearing pressure axially fixed. Can bear radial load and smaller in either direction axial load.
(10) GE ... DS-type
Outer ring fitting groove and lubrication grooves. Only limited to large size bearings. Can bear radial load and smaller in either direction axial load (fitting groove side can not bear axial load).
Angular contact spherical plain bearing performance
   GAC ... S-type inner and outer rings are hardened bearing steel, the outer ring groove and oil hole. Can bear radial load and axial direction (joint) loads.
Thrust bearings feature
    GX ... S-type shaft ring and seat ring are hardened bearing steel; seat ring with grooves and hole. Can withstand axial load in one direction or the combined load (at this time the radial load value not greater than 0.5 times the value of axial load).

Quality check bearing operation tips

Bearings should be checked after installation, you should ensure that the bearing in place, rotating flexible cable wiring, improper installation, such as bearings, bearing temperature will rise quickly and damage, and even death card bearing fracture or other serious accidents.
First, the rotation of the bearing sounds with a stethoscope and other tests, there is a strong metal noise, abnormal sound, irregular sound, etc. Exceptions. The reasons are poor lubrication, shaft or bearing bad precision, bearing damage, foreign invasion and so on.
Secondly, bearing temperature, and can be based on speculation bearing the external temperature. But the use of direct measurement of the bearing outer ring hole temperature is more accurate. Bearing temperature gradually increased from the start of operation, typically 1 to 2 hours after the temperature to stabilize. If the bearing bad installation, the temperature will soar, abnormal high temperature. The reason such as too much lubricant, bearing clearance is too small, poor installation, seal friction and too big. The case of high-speed rotation, the bearing structure, the choice of lubrication is the cause of the error.
Third, small machinery can be rotated by hand to verify rotate smoothly. Check the project due to nick, indentation caused by dysfunctional, because poor installation, mount the torque generated by poor processing unstable, because clearance is too small, the installation error, seal friction torque caused by too large and so on. Without exception, you can begin powering.
Fourth, the large machinery can not be manually rotated so cut off the power immediately after starting load, machine idle to check for vibration, noise, etc. in contact with the rotating member is to confirm no abnormality, into the power running.

Rolling technical standards and precautions

1, with the use of the bearing and shaft hole basis, bearing and housing system using the base axis. Bearing Size Tolerances and rotation accuracy is obtained by GB307-84 requirements.
2, with the bearing with the journal and the bearing housing bore by GB1031-83 requirements, the journal roughness Ra value of less than 1.6μm, bearings inside the hole roughness Ra value of less than 2.5μm.
3, with and ZGCr15 steel GCr15 bearing rings and rolling midnight, its rings and roller hardness value should be 61 ~ 65HRC; using GCr15SiMn and ZGCr15SiMn steel, the hardness value should be 60 ~ 64HRC. Hardness inspection method and the same part by the uniformity of hardness JB1255 requirements.
4, check the bearing radial clearance and axial clearance shall comply with the requirements of GB4604-84.
5, the bearing inner and outer ring raceway should be no peeling, severe wear, inner and outer rings are not allowed to have cracks; ball should be no wear, cage without serious distortion, rotation no abnormal noise and vibration, stop should be gradually stopped.
6, C-level tolerance for tapered roller bearings, roller and ring raceway contacts accuracy, under the action of a certain load, check for coloring, contact marks should be continuous, rolling contact length of not less than 80 picture-line.
Bearing life is associated with manufacturing, assembly, use all closely related, must make every link in order to make the bearing in the best operating condition, thus extending bearing life.
    1, the shaft and the bearing housing tolerances choice and control: bearings are pressed into block after no sense should be flexible rotation. If significant rotation is not flexible, it indicates that the shaft size is too large, tolerance to downward. Such as bearings pressed into the shaft turned by hand obvious "imperfections" sense, it may be too much tolerance of the shaft or shaft roundness bad. So good control shaft and the bearing housing tolerance should also control the roundness, many domestic manufacturers only tolerance control, no roundness control.
2, the bearing assembly methods: Because the bearings are precision products, such as improper assembly is very easy to damage the bearing channel, leading to bearing damage. Bearing in the assembly should have a dedicated mold and can not beat the pressed into the shaft when the force only a small circle, the circle can only push a large circle force. Assembly requires the use of pneumatic or hydraulic, press-fit upper and lower mold to remain outside the state level, if inclined bearing channel will lead to damage due to power, leaving the bearing guide ring.
3, the assembly to prevent foreign bodies: Bearing mounted to the rotor can easily do balancing balancing generated when the iron filings into the bearing, so it is best to do before loading the bearing dynamic balancing. There are some manufacturers in order to facilitate assembly, the assembly in the bearing chamber coated with some oil or grease lubricant effect, but the operator is often difficult to control the amount, if the oil or grease in the bearing chamber accumulates more in the bearing rotation is easily along the shaft into the bearing. Bearing chamber preferably not coated with oil or grease, such as non-coated bearings shall not be have to control indoor accumulates.
4, paint rust prevention: paint rust characterized by multiple in sealed-type motor, motor in the assembly sounds good, but put in the warehouse for some time, the motor becomes very abnormal sound, remove the bearing severe rusting. Many manufacturers will be considered a bearing problem, through our continuous publicity, and now the motor plant has been realized mainly insulating paint problems. The problem is mainly because the insulating paint out of the volatile acidic substance at a certain temperature, humidity, the formation of corrosive substances cause corrosion of the bearing channel bearing damage. The problem can only be a good selection of insulating paint, and after a period of time after drying ventilation assembly.

Crossed roller bearings scope

Crossed roller bearings, can withstand the load from all directions (eg axial thrust load or momentum, etc.). Crossed roller bearings roller and track appearance due to exposure status quo, and thus, bearing elastically deformed by the load is small can.
Cross roller bearing widely used in such as industrial robots, tasks machinery and medical facilities, and cross roller bearing require high rigidity, high speed tight and able to ensure accurate place under cross roller bearings, cylindrical roller due child at 90 ° to the surface of the V-shaped groove rolling bearing retainer by the distance to be arranged perpendicular to each other, so a cross roller bearings can bear radial load, axial load and moment load and all direction of the load.
The minimum inner ring size is miniaturized, the special pattern is close to the limit thin compact size, and have high rigidity, so the most suitable for the industrial robot joint portion or the rotary part.

2013年7月4日星期四

The main cause bearing rust corrosion

Bearing rust corrosion caused by many reasons, mainly due to the following six points:
1, some enterprises in the production process of bearing no strict rules on cleaning rust rust and seal packaging requirements for the processing of the bearing parts and assembled finished bearing anti-rust treatment. If ferrule turnaround process turnaround time is too long, the outer cylindrical contact with corrosive liquids or gases.
2, some companies used in the production of anti-rust oil, kerosene and other cleaning products reach quality technology requirements.
3, the bearing steel prices dropped lower and lower, resulting in a gradual decline in bearing steel. Such as high levels of non-metallic inclusions in steel (elevated sulfur content in the steel and the material itself anti-corrosion performance degradation), microstructure deviation. Currently used by manufacturers source more complex bearing steel, steel quality is mixed with fish and dragon beads.
4, some enterprises poor environmental conditions, high levels of harmful substances in the air, working space is too small, it is difficult for effective rust treatment. Coupled with hot weather, production workers violation rust there are some procedures such phenomena exist.
5, some enterprises rust-proof paper, nylon paper (bags) and plastic tube packaging materials such as bearings rust does not meet the requirements for packaging bearing oil seal is one of the factors leading to corrosion.
6, some companies bearing ring turning and grinding margin margin is too small, cylindrical on the oxide, carbon layer is not completely removed one of the reasons.

Deep groove ball bearing seals applications

Deep groove ball bearing is the bearing seal member in the normal operation in the harsh environment of the key components, bearing seals protect bearings from erosion and pollution of the bearing lubrication in a good clean conditions, extending bearing life.

Generally, deep groove ball bearing seals greater role than the dust cover, and by rotating flexible and low speed rotation restrictions. Bearing seals in the design, we must consider the performance of lubricants and conveyor systems and ideal working conditions.

For bearing applications in use to withstand high loads, a strong impact force and prevent water and dust particles such as rust invasion, and developed a new type of high load capacity, sealed, clean and lubricated bearing seals.

Experience has shown that in a polluted working conditions, easy to enter the bearing clastic particles, and these particles can damage the raceway debris, causing stress concentration. Also, if uneven lubrication, hard contact of the metal surface, resulting in a slight "peeling" corrupted, the contact area can lead to stress concentration, so that these two results of the stress concentration of the metal surface crack spread and ultimately shorten bearing life.

Studies show that, by changing the organization of bearing steel, impurity contamination can be improved bearing lubrication conditions or under conditions edge working life, to improve the bearing stress concentration at the edge of the release ability.

The best practical protection measures are bearing: When the impurity one appears, then stop it. New deep groove ball bearing seals of both these two advantages. The new hole type bearing seals only solve suppress a negative pressure in the bearing to prevent the water, the main sealing member is not directly exposed to water, the water from "breathing", but also play an impurity blocking the recess slot at the function. Conventional bearing seals the rotating and the stationary state is a linear contact, to maintain the strength of the tight sealing performance of the sealing member and this work, the contact instead of linear contact with the surface to accommodate the bearing rotating sealing requirements, both tight seal, not produce a large negative pressure.

To confirm the new hole type bearing seals the effectiveness of the test, the bearing operating speed range to 100r/min 700r/min, and 294kN radial load is continuously applied while the water spray of about 100L/min. General hole bearing seals in this period, the negative pressure increases, while the new-hole bearing seals inhibited the negative, to ensure the normal operation of the work.

Deep groove ball bearings rust knowledge

Deep groove ball bearings division between the rust and rust usually finished rust.
Workers between the rust belongs antirust processing, usually in 3-30 days. Will generally water-based rust inhibitor can be. The advantage of water-based rust inhibitor is a simple operation and low cost. And rust after degreasing cleaning is not required.
Finished rust generally refers to the deep groove ball bearing assembly before storage or rust after delivery, usually within a month to 2 years or so. General use apply anti-rust oil or rust VCI paper packaging. VCI antirust paper packaging has the advantage of good rust, free cleaning before assembly, easy to operate, environmentally friendly energy.
VCI antirust paper will always release a small amount of rust inhibitor (VCI Definition: volatile corrosion inhibitor). In this paper, the package, the package is formed in a protective layer of gas can be reliably suppressed corrosion of deep groove ball bearings. VCI rust-proof paper in direct contact with the bearing and have anti-rust within a certain distance; bearing VCI antirust paper packaging rust, rust-proof up to 3 years; bearing VCI antirust film packaging rust, rust up a years. This is the most used product Harbin HRB, now commonly used in plastic barrels rust processes.

Sealed deep groove ball bearings with grease on one side only

We use the process of deep groove ball bearing, bearing seals occasionally pry open the lid, this time we will find that while there is some bearing full of grease, while the other side there is no grease; while some bearing on both sides evenly fat distribution, especially the high price of the bearing, this is what causes it?
We know that the bearing during operation is the need to grease and rust, especially sealed deep groove ball bearings, grease the bearing can not be high-speed operation, will greatly shortened life expectancy. The bearing in the production process is a process up to a, the bearing inner ring and the balls, the cage is assembled, the first thing is to wash, rinse after the pressure side of the seal cover, and then flip over bearing, plus fat (Average plus the bearing interior volume is 30% ~ 35%), and then a cover.
Here we found, sealed deep groove ball bearing with one side in the production process are not added fat, grease applied to only one side only; if both sides, then add oil, bearing the manufacturing process, the more of a process, so the production efficiency will be reduced.
At this time someone will ask, why would some bearing grease on both sides of it? If the bearing grease seals on both sides, this one is the price is relatively high, and the other is used over the bearing. Why do you say? This is the high price of bearings are generally better quality, this is the result of deep groove ball bearing side full inspection, and that is to go through the rotating bearing test, after the rotation bearing grease on the inside of a uniform distribution; another is bearing After using, used, oil will certainly be evenly distributed.
So says the new deep groove ball bearings with grease on both sides of only one side while the other side is not normal, users do not worry, just take a few turns bearings, or turn a few minutes to get the machinery above, bearing grease on the inside of the uniform rotation , do not affect the use.

Bearing seal in the form of non-contact

Non-contact sealed bearings, there are three common forms: gap seals, seal and slinger labyrinth seal. Because there is a gap, in addition slinger seals, non-contact seals are used for grease lubrication occasions. In order to improve the reliability of sealing can be combined with various types of sealing.
Non-contact bearing sealing device has the following advantages: at the sealing gap there is a lubricant in addition to internal friction of the friction will not be other, therefore, non-contact seals no wear; use a very long time is not have a significant temperature rise; applicable where high speed. However, sealing the gap can not be too large, otherwise the sealing effect poor.
Bearing support portion includes a non-contact seals: sealing gap. Its structure is simple and can meet the general requirements under seal. E selection of the gap d ≤ 50mm, e = 0.25 ~ 0.40mm; d> 50mm, e = 0.25 ~ 0.6mm. Groove seal. After filling the trench so that dust is hard to invade the grease, with the ring groove and the helical groove forms. Ring groove generally have three. Width b = 3 ~ 5mm; groove depth t = 4 ~ 5mm.
Labyrinth seal. When the maze labyrinth filled with grease and sealed better than trench sealed. Bearing labyrinth seals can be divided into two types of radial and axial. Radial and axial clearance selection: d ≤ 50mm, a = 0.20 ~ 0.30mm, b = 1.0 ~ 1.5mm; d = 50 ~ 200mm, a = 0.30 ~ 0.50mm, b = 1.5 ~ 2.0mm.
Oblique labyrinth seal. It is used for shaft deflection large curved road slope can swing with the center. Oblique curved road labyrinth seal can be achieved after the grease filled in a better sealing effect.
Slinger seal. Oil lubrication, the shaft out of the trench or install a ring, you can drain the oil out of the desire thrown radially through the bearing cap assembly back into the oil chamber with oil sump hole. You can also close the bearings mounted oil ring toss, this structure is often used in combination and crevice seal.
Stamping steel bearing labyrinth seal. The stamped steel labyrinth seal consisting of synthetic, with which we can rely on stamping steel mounted on the shaft or housing, not axially tightened, simple structure. If the stamping steel labyrinth maze filled with grease, with good sealing effect.

2013年7月2日星期二

How to choose a suitable bearing type

Select the bearing type, bearing fully grasp the conditions of use is essential. The following table lists the main analysis items:

Analysis Project Selection Method

1) bearing the mounting space in the bearing installation space can accommodate a bearing shaft due to the design type by focusing on the rigidity and strength of the shaft, it is generally first determine the shaft, the bearing diameter.

But bearing a variety of sizes and types of series, should choose the most suitable bearing type.

2) Load bearing load size, direction and nature of [the load bearing capacity of a basic rated load, said its value in the bearing dimension table] bearing load full of changes, such as the size of the load, whether only radial load, axial load is one-way or two-way, and so the degree of vibration or shock. After considering these factors, again select the most suitable bearing type.

In general, the same inner diameter of the bearing radial load capacity in the following order: deep groove ball bearings <angular contact ball bearings <cylindrical roller bearings <tapered roller bearing <Spherical Roller Bearings

3) Speed ​​can adapt to mechanical speed bearing types [bearing speed limit value basis using the speed limit, said its value in the bearing dimension table] bearing speed limit not only take on the bearing type is also limited to the bearing size, cage type, accuracy class , load conditions and lubrication methods, therefore, must be considered when selecting these factors.

The following bearings are mostly used for high-speed rotation:

deep groove ball bearing, angular contact ball bearings, cylindrical roller bearings

4) with the required precision rotation rotation precision bearing types [bearing dimensional accuracy and precision rotation by bearing type has been standardized GB]? Spindle, respectively, gas turbine and control the machine requires high rotational accuracy, high speed and low friction, Then you should use more than 5 precision bearings.

Generally use the following bearings:

Deep groove ball bearing, contact ball bearing, cylindrical roller bearings

5) Just performance to meet the required mechanical rigidity of the bearing shaft type [bearings under load, the rolling element and raceway contact portion is elastically deformed. "High rigidity" refers to the amount of deformation that the elastic deformation is small] in the machine spindle and the last stage deceleration devices, automotive parts, to improve the rigidity of the shaft must also improve the bearing stiffness.

Roller bearings under load deformation born smaller than ball bearings.

The bearing preload (negative clearance) can improve rigidity. This method is suitable for angular contact ball bearings and tapered roller bearings.

6) The inner and outer rings relative inclination of the bearing inner and outer rings relative inclination produced factors (such as deflection caused by the load shaft, the shaft and the housing or the installation error in accuracy), and choose to adapt this Conditions of Use bearing type. If the inner and outer rings relative inclination is too large, due to an internal load bearing damage. So should choose can withstand this tilt bearing type.

In general, allowing the tilt angle (or aligning angle) in the following order:

Cylindrical roller bearings, tapered roller bearings, deep groove ball bearings (angular contact ball bearings), self-aligning roller (ball) bearings

7) Installation and removal of detachable periodic inspection frequency and method of assembly and disassembly frequent disassembly, use separable inner ring and outer ring cylindrical roller bearings, needle roller bearings and tapered roller bearings is more convenient.

Tapered hole aligning ball bearings and tapered bore spherical roller bearings through the use of fasteners or withdrawal sleeve facilitates assembly and disassembly.

Rolling with the sliding bearing has the advantage compared to

Rolling and plain bearings, has the following advantages:

1. Rolling bearings friction coefficient smaller than the sliding bearing, high transmission efficiency. Average coefficient of friction bearing 0.08-0.12, and the rolling friction coefficient is only 0.001-0.005;

2. Rolling has achieved standardization, serialization, universal, suitable for mass production and supply, use and maintenance is very convenient;

3. Rolling bearing steel, and after heat treatment, therefore, bearing not only has high mechanical properties and long life, and can save manufacturing plain bearings are used in more expensive non-ferrous metals;

4. Bearing internal clearance is small, high precision machining of parts, therefore, high running accuracy. At the same time, by pre-loading method of increasing the rigidity of the bearing. This precision machinery is very important;

5. Some bearing can support radial load and axial load, so you can simplify the bearing support structure;

6. Since rolling high transmission efficiency, less heat, therefore, can reduce oil consumption, lubrication maintenance more easy; self-lubricating bearings

7. Rolling can be easily applied to space any orientation on uranium.

However, everything is divided into two, bearing also has some drawbacks, mainly:

1. Bear the load bearing capacity than the same volume of the sliding bearing is much smaller, therefore, the radial bearing large size. So, in the case of heavy load to bear and small radial size requirements, structural requirements for compact applications <as crankshaft bearings), the use of sliding bearings;

2. Bearing vibration and noise is higher, especially in the use of late is particularly significant, therefore, demanding precision, without Xu Youzhen moving occasion, bearing difficult competent, generally used in sliding bearings better.

3. Rolling of metal shavings and other foreign matter are particularly sensitive to foreign matter enters the bearing will produce a large vibration and noise intermittently, also cause early damage. In addition, because the metal clip bearing impurities also prone to the possibility of early damage. Even early damage does not occur, the life of rolling bearings have certain limits. In short, the life of rolling bearings shorter than the sliding bearing.

However, Rolling and plain bearings, compared advantages and disadvantages of each occupy a certain application of occasions, so the two can not completely replace each other, and each to a certain direction, to expand their fields. However, due to the outstanding advantages of rolling bearings, quite latecomers trend. Currently, the rolling bearing has developed into a major mechanical type, application more widely.

Hybrid bearing structure type and Precautions

1, the depth of the cavity structure of hydrodynamic bearings: light load for high-speed machine tool spindles, such as M1432 cylindrical grinding, MGA6025 tool grinding.

2-hole torus throttle chamber depth Hybrid Bearing: Suitable for medium-speed machine tool spindle contained, such as MG1432 cylindrical grinding, MM7150 flat grinding, M1080 centerless grinding, roll grinding.

3, dowel pin type internal feedback hydrodynamic bearings: load and speed variations for a large range of machine tool spindles.

4, conical hydrostatic bearing: inner circle suitable for high speed grinding spindle system (such as the 2110 inner circle grinding), spindle, and the inner channel grinder.

Precautions

1, the normal use should be replaced after one year # 2 spindle oil and coarse and fine filter.

2, the normal use when the oil pump to add 3-layer silk cloth must be filtered to join.

3, the spindle pulley, wheel loading and unloading work must be in a state where the pumping station. That the spindle hydrostatic oil floating state. This does not damage the shaft and hydrodynamic bearings.

4, before work observation wheel spindle grinding hydrostatic pressure and pumping stations are within specifications.

5, equipment downtime, we must first stopped grinding motor until wheel completely stopped, then turn off the pump, or easy to damage the grinding head.

6, for any component on the pump, be sure to remove high-pressure inlet hose fittings, finished parts replacement after self-cycle oil for 15-20 minutes before the inlet pipe connected to the grinding head, thus ensuring enter the grinding spindle oil is filtered through the fine ultra-clean spindle oil. This can extend the life of the hybrid spindle.

Bearing quality appearance

1, the bearing parts are not allowed cracks, sharp edges, burrs and rust; raceways are not allowed on the channel processing traces; inner and outer rings, balls Face ultra-fine grain should be uniform, not allowed to have scratches, bumps;
2, the bearing parts with surface grinding lines should be consistent with the rules, does not allow a spiral pattern, chatter, yin and yang face and grinding marks, does not allow support printing and significant measurement traces, does not allow bump hurt and obvious color differences.
3, the parts of the surface oxide are not allowed. Chamfering rings, inner diameter, outer diameter required lighting process.
4, the bearing ring parts by pickling, the work surface should not have burned, with the surface should not have been visible burns pickling without affecting hardness testing.
5, the assembly chamfer.
a. assembly chamfer dimensions, chamfered shape should be consistent with our product drawings requirements.
b. chamfered surface, no rust and bump hurt.
6, ball
Ball appearance quality standards should be consistent JB/T10861 standards.
7, cage
Exterior surfaces should be smooth, no glitches, no bumps, no rust and obvious color difference, does not allow bruise contusion, deformation and trachoma and other cosmetic defects.

Bearing reducer mechanism works

Gear is widely used as a mechanical transmission, a variety of machine tools in almost every drive gear. In the CNC servo feed system uses gear transmission has two purposes. First, the high-speed torque servo motor (such as stepper motors, DC and AC servo motors, etc.) change the output of low speed high torque actuator input; another is to make the ball and table moment of inertia in the system has a smaller proportion of secondary school. In addition, the open-loop system can ensure the required precision of movement.
To minimize the backlash of CNC machining accuracy, often in the structure to take measures to reduce or eliminate the empty drive gear error. If the wrong gear tooth dual-chip method using eccentric adjustment gear center distance or using axial shimming method to eliminate the backlash.
 Compared with the use of synchronous belt in CNC machine tool feed drive chain using gear reduction, easier to produce low-frequency oscillations, thus reducing mechanism often configured dampers to improve dynamic performance.
 Timing belt is a new belt drive. He used the toothed belt and pulley tooth meshing teeth sequentially transmit motion and power, and thus both belt drive, chain drive gear and advantages, and no relative sliding, the average transmission more accurate, high transmission accuracy and toothed belt high strength, thickness is small, light weight, it can be used for high-speed transmission. No special tensioning toothed belt, so the role of the shaft and the bearing load is small, the transmission efficiency is high, is now widely used in CNC machine tools. Timing belt main parameters and specifications are as follows:
    1) pitch pitch p is the pitch line of two adjacent teeth in the distance. As strong layer of the same length at work, so strong layer centerline is defined as toothed belt pitch line (neutral layer), and the perimeter of the pitch line L as the nominal length of toothed belt.
    2) Modulus Modulus is defined as m = p / π, the toothed belt size calculated a main basis.
    3) Other parameters Other parameters toothed belt and size involute rack basically the same. The formula toothed belt tooth involute rack with different because toothed belt pitch line in a strong layer, rather than the tooth high school.

Bearings to reduce the thermal deformation of machine tools

In the external heat source, the machine parts will be in different degrees of thermal deformation of the workpiece and the relationship between the relative movement between the tool was broken ring, the machine is decreased quarter. For CNC machine tools, because the whole process is the calculation of the command control, the thermal deformation of the more serious. To reduce the thermal deformation structures in the CNC machine is usually used the following measures.
Internal heat generated when the machine's main heat source thermal deformation, the heat source as possible should be separated from the host.
Control the temperature rise
In taking a series of measures to reduce heat, thermal deformation of the situation will improve. However, to completely eliminate the heat source outside the machine is often very difficult or even impossible. It must be a good heat dissipation and cooling to control the temperature in order to reduce the impact of heat. Which portion is more effective heating area of ​​the machine forced cooling, the machine can also be a method by heating the low temperature portion, so that the machine of the convergence point temperature, which can reduce warpage caused by temperature difference.
In the same heating conditions, the thermal deformation of machine tool bodies also have a significant impact. Such as CNC machine tools used in the past are likely to be single-column body double column institutions instead. As symmetrical, double column main body of the heated produce a vertical axis in addition to translation, the deformation is small in the other direction, the vertical axis direction can be easily moved by a correction amount to compensate for the coordinates.
 The CNC lathe headstock, the spindle should be thermal deformation occurs in the vertical direction of the tool cutting. This allows machining diameter spindle thermal deformation on impact is minimized. Should be reduced as much as possible in the structure of the spindle to spindle center distance from the ground in order to reduce the amount of thermal deformation, and should make consistent temperature before the headstock to avoid deformation to tilt the spindle.
 CNC machine tools in the ball often in the expected load, high speed and cooling work under poor conditions, so screw easy to heat. Ball heat production caused serious consequences, especially in the open-loop system, it will make the loss of the feed system positioning accuracy. Currently some machines with pre-pull method to reduce the thermal deformation of the slewing bearing. For these measures does not eliminate the thermal deformation measurement results can be compensated by the numerical control system sends pulses to be amended.

2013年7月1日星期一

LYVSG

Luoyang VSG Bearing Co.,Ltd is one bearing production enterprise with character of research and development in China which specially produces uniform section slim bearings, light cross roller bearings, harmonic driver bearimg, and other precise bearing used in field of industrial robot and aerospace.Angular contact bearing
 
The company is member of China Robot Technique and Application magazine, member of Chinese Bearing industry Association, product of uniform section slim bearing series proposal of national "torch" project plan in 2005,approved for new fund project of the national ministry of science and technology in 2005, and past national acceptance in 2007.
 
Our company can produce all kinds of slim bearing with inner diameter 20mm to external diameter 660mm,light cross roller bearing with accuracy grade from P0 to P4 grade, annual output of thirty thousands.Cross bearing