(1) the preparatory work before dismantling
a, the workplace should be spacious and bright, flat and clean.
b, disassembly tools are well prepared, appropriate specifications.
c, according to the different purposes of the preparation of the parts placed on the shelf, separating basin, oil drums, etc.
(2) the basic principles of disassembly of machinery
a, according to the model and the relevant information can be clear about its structural characteristics and assembly relationship, and then determine the decomposition of the disassembly of the method, steps.
b, the correct choice of tools and equipment, when the decomposition of the difficulties encountered in the first to identify the causes, to take appropriate methods to solve the problem, not allowed to hit the hammer to prevent damage to the parts and tools, and can not be used to measure, pliers instead of a hammer and cause damage.
c, in the disassembly of parts or combinations of parts with a specified direction, marking, should remember the direction and marking, if the loss of marking should be re-marked.
d, in order to avoid damage or loss of the removed parts, should be stored separately according to the size and precision of the parts are different, according to the order of dismantling, precision and important parts are stored specifically for safekeeping.
e, removed bolts, nuts, etc. in the case does not affect the repair should be loaded back to the original position, so as to avoid loss and facilitate assembly.
f, according to the need to dismantle, on the individual not dismantled to determine the condition of its good can not be dismantled, on the one hand, can save time and labor, on the other hand, can avoid disassembly process damage and reduce the accuracy of parts assembly. But the parts to be disassembled must be disassembled, not to save trouble and sloppiness, resulting in repair quality is not guaranteed.
2, mechanical assembly
Mechanical assembly process is to determine the quality of mechanical repair is an important part of the process, so it must be done:
(1) be assembled by the parts themselves must meet the specified technical requirements, any unqualified parts can not be assembled. For this reason, the parts must be assembled before a strict test.
(2) must choose the correct method of coordination to meet the requirements of precision. A large number of mechanical repair work is to restore the accuracy of the fit of the mating parts, can take the selection, repair, adjustment and other methods to meet this requirement. With the gap need to consider the impact of thermal expansion, for the different coefficients of expansion of the material composition of the fit, when the assembly of the ambient temperature in the work of the temperature difference is large, the gap caused by the change should be compensated.
(3) analyze and check the accuracy of the assembly dimensional chain, through the selection and adjustment to meet the accuracy requirements.
(4) deal with the order of assembly of machine parts, the principle is: first inside and then outside, first difficult and then easy, first precision and then general.
(5) Selection of suitable assembly methods and assembly equipment and tools.
(6) Pay attention to the cleaning and lubrication of parts. Assembled parts must first be thoroughly cleaned, for moving parts to be coated with clean lubricant on the relative moving surface in line with the requirements of the work.
(7) pay attention to the assembly of the seal to prevent "three leaks". To use the provisions of the sealing structure and sealing materials, can not use arbitrary substitutes. Pay attention to the quality and cleanliness of the sealing surface. Pay attention to the assembly method of the seal and assembly tightness, the static seal can be used to seal the appropriate sealant seal.
(8) pay attention to the assembly requirements of the locking device, in line with the safety regulations.
(9) pay attention to the assembly of intermediate links in the quality inspection.
3, mechanical cleaning and inspection
(a) mechanical cleaning
1, remove oil
Oil is grease and dust, rust and other adherents, it does not incorporate water, but into the organic agent. In addition to the mechanical method of decontamination, can also be removed by chemical or electrochemical method.
(1) chemical decontamination method:
1, organic solvent decontamination: commonly used organic solvents are gasoline, kerosene, diesel fuel, acetone and so on.
2, alkaline solution degreasing: such as caustic soda, sodium carbonate, sodium silicate sodium phosphate. Cleaning to increase the solution temperature and agitation can accelerate the effect of oil removal,
Generally can be heated to about 80 ℃, after washing should be rinsed with hot water, and blow dry with compressed air.
(2), electrochemical degreasing method: the use of electrolysis when the two electrodes produce bubbles of mechanical agitation and stripping effect of grease from the surface of the parts of the method called electrochemical degreasing method. The method has the advantages of fast speed, high efficiency, thorough oil removal.
(B) mechanical inspection
The content of the inspection is as follows:
1 parts inspection
including the parts of the geometric accuracy of the test, such as the size of the parts, shape; parts of the surface quality of the test: such as surface roughness, surface damage and other defects, etc.; parts of the mechanical properties of the test: such as the parts of the strength, hardness, the balance of the parts, spring stiffness, etc.; hidden defects of the parts, the mechanical performance test: such as the strength of the parts, hardness, parts, balance, spring Rigidity, etc.; parts of the hidden defects of the test: such as voids, plus slag, microscopic cracks, etc..
2 assembly test
such as the relative position of the parts and parts, the gap or the amount of interference with the parts; the balance between parallel shafts, the coaxiality between the front and rear axes and so on.
3 machine inspection
Machine inspection is the test of the technical condition of the machine. Including mechanical work capacity, power economic performance, etc., inspection methods are as follows:
A inspection method: this method only by eye, hand, ear to test and judgment, simple and feasible, widely used, can be divided into:
(1) visual method: the parts of the surface damage, such as roughness, grooves, cracks, scratches, flaking (peeling), cracks, as well as parts of the larger and obvious deformation, Serious wear and tear, surface annealing and ablation, etc. are determined visually or with the help of magnifying glass observation. There are like rigid coupling paint film rupture, flexible coupling misalignment, threaded connections and riveted seals add paint film rupture can also be used to visually determine.
(2) knocking method: for the shell parts are not obvious cracks, bearing alloy and the combination of the bottom tile, etc., can be heard by knocking sound crisp or hoarse to determine the good and bad.
(3) Comparison method: the new standard parts with the parts being tested compared to identify the technical status of the parts being inspected. Such as the free length of the spring, the length of the chain, the quality of rolling bearings and so on.
B Measurement method: wear and tear or deformation of the parts will cause changes in size and shape, or fatigue caused by technical performance (such as elasticity) decline. Can be measured by measuring tools and instruments and against the allowable standards to determine whether to continue to use, or to be repaired or scrapped. For example, the rolling bearing clearance measurement, temperature rise measurement, the measurement of gear wear, the measurement of spring elasticity, etc..
C Detection method: the hidden defects of the parts, especially the important parts of the detection of minor defects, to ensure the quality of repair and use of safety is of great significance, must be carried out seriously, there are some of the following approaches:
(1) infiltration display method: the clean parts will be immersed in kerosene or diesel oil for a few moments, after removing the surface will be wiped dry, sprinkled with a layer of talcum powder, and then Tap the non-working surface of the parts with a small hammer, if the parts have cracks, due to vibration so that the oil immersed in the cracks seeped out, and make the cracks at the talcum powder shows a yellow line mark.
(2) fluorescent display method: first the surface of the parts to be tested washed, preheated with ultraviolet lamp irradiation for 10 minutes, so that the surface of the workpiece observed under the ultraviolet lamp was dark purple, and then evenly coated with fluorescent display liquid on the surface of the parts work, you can show a yellow-green defects traces.
(3) flaw detection method: magnetic particle flaw inspection, ultrasonic inspection, radiographic inspection. Mainly used to determine the internal defects of parts and weld quality.
(D) the balance of the rotor
1, the type of rotor imbalance
(1) static imbalance: unbalanced weight on the rotor can be synthesized into a rotor rotating only a centrifugal force, and can be determined in the state of static force, it is called static imbalance.
(2) dynamic unbalance: if a rotor can be synthesized in two equal size, opposite direction, but not in the same diameter of the unbalanced weight, the rotor can be balanced in static state, but in the rotation of an unbalanced force will produce a force coupling, which can not be determined in the static state can only be identified in the dynamic, it becomes dynamic unbalance.
(3) mixed unbalance: if in a rotor, both static unbalance, but also dynamic unbalance, known as mixed unbalance.
2, the balance of the rotor
In order to eliminate the unbalance on the rotor or force couples, must be measured where the unbalance of the orientation and size of the mass, and then try to be balanced, this process is called the rotor to find the balance. Generally can be divided into two kinds of static balance and dynamic balance.
(1) static balance: where in the static can be measured rotor unbalance quality and orientation and can eliminate the rotor by removing the weight or aggravation of the rotor bias and make the rotor to achieve the balance of the method called static balance.
(2) dynamic balancing: where only in the dynamic determination of the rotor unbalance quality of the orientation, as well as to determine the balance of the quality should be added to the location and size of the balance of the method is called dynamic balancing. Dynamic balancing can not only eliminate the dynamic imbalance of the force coupling, and can eliminate the static imbalance of the centrifugal force, so it can be used to find a variety of columnar and tapered rotor balance.
(E) the overall inspection of equipment
The overall inspection of equipment is a comprehensive quality identification of mechanical equipment after repair, is to ensure that the delivery of machinery and equipment for use with good performance and safety and reliability of the important links. The overall test includes no-load test run, load test run test run after the inspection steps. Important equipment also need to carry out pressure tests and tightness test.
1, no-load test run: first of all, check the connection, fastening, lubrication, sealing, operation, test manipulation system, regulation and control system, the action and role of the safety device, and make appropriate adjustments, while checking all kinds of instrumentation instructions are in line with the prescribed standards. For the assembly performance test is not carried out, to branch test run, test run found in the fault and abnormal sound, temperature rise, jumping, etc. without eliminating the load test shall not be carried out.
2, load test run: load test run is in the no-load test run after normal. Through the load test run to determine the mechanical power performance, economic performance, operating conditions and maneuvering, adjustment, control and safety devices to meet the operational requirements.
3, check after the test run: after the load test run must be on all parts of the deformation, loosening, overheating, breakage and other positive checks, while checking the sealing of the relevant parts of the friction surface of the contact situation.
4, equipment pressure test and tightness test:
(1) hydraulic test: usually used to check the weld, connecting parts of the tightness and strength. Generally use water as a medium, so also known as hydraulic test.
(2) pneumatic test: for institutional reasons or containers do not allow the presence of trace residual liquid in the container, to pneumatic test detection.
(3) tightness test: for a variety of storage gas or liquid pressure vessels, should be weld tightness test to ensure no leakage. Usually can be used gas tightness test, kerosene leakage test and ammonia penetration test and other methods.
Three, bearing class
Bearings: according to the different nature of friction between the axle diameter and bearing, divided into sliding bearings and rolling bearings.
1, sliding bearings
(1) according to the lubrication state, sliding bearings can be divided into non-liquid friction sliding bearings and liquid friction sliding bearings two categories.
Non-liquid friction sliding bearing is in the shaft diameter and tile surface, due to the lubricant adsorption and the formation of a layer of very thin oil layer, known as the boundary oil film, it makes the shaft diameter and the surface of the tile has a part of the direct contact, and the other part of the oil film is separated from the direct contact, so as to reduce the coefficient of friction of the sliding surface.
Liquid friction sliding bearing is in the shaft diameter and shingle surface has thicker lubricating oil layer, the sliding surface is completely separate and not direct contact. The friction between the sliding surfaces becomes the liquid friction inside the lubricant layer, so the friction coefficient is greatly reduced.
(2) according to the direction of the load bearing, can be divided into two categories of centripetal plain bearings and thrust plain bearings.
Centripetal plain bearings
Commonly used centripetal plain bearings mainly have the following three types: integral bearings, common integral bearings are in the machine frame boring out bearing holes, sometimes in the hole inlaid with a bushing; Split bearings, that is, for a split plain bearings, with the bolt to fix it on the frame. Through the lubrication device on the bearing cover, the lubricant can be sent to the surface of the shaft diameter; Spherical bearing, the outer surface of the shaft tile of this kind of bearing is made into a spherical shape, which can be rotated appropriately in the corresponding spherical surfaces of the bearing cover and the bearing seat to adapt to the shaft bending of the axial deflection produced.
Thrust sliding bearing
Thrust sliding bearing mainly bear axial force, it has horizontal and vertical two kinds.
2, rolling bearings
(1) rolling bearing classification
Based on the shape of the rolling body, rolling bearings can be divided into: ball bearings, roller bearings.
Based on the direction of the load bearing, rolling bearings can be divided into: centripetal bearings, mainly to bear the role of radial load; centripetal thrust bearings, can withstand the combined effect of radial and axial load; thrust bearings, can only bear the axial load.
(2) rolling bearing type selection
A According to the size, direction and nature of the bearing load
①, the load is small and smooth, it is appropriate to use roller bearings.
②, when the bearing only bear radial load, can choose radial ball bearings or centripetal short cylindrical roller bearings; when the bearing only bear axial load, can choose thrust ball bearings.
3, when the bearing at the same time by the axial load and radial load, should be based on the axial load A and radial load R relative value to consider.
a When A is much smaller than R, radial ball bearings can be used.
b When A<R, use centripetal thrust ball bearings or tapered roller bearings.
c When A>R, use centripetal thrust ball bearings with large contact angle and tapered roller bearings with large taper angle.
d When A is much larger than R, thrust bearings and radial bearings can be used in combination to carry axial and radial loads respectively.
B According to the speed of the bearing
1, when the size and accuracy are the same, the limit of ball bearings is higher than that of roller bearings, so the ball bearings are easy to be used in the shaft with higher speed.
2, subject to axial load of high speed shaft, it is best to use centripetal thrust ball bearings, not use thrust ball bearings. Because of the high speed, the centrifugal force of the rolling body is very large, will make the bearing working conditions deteriorate.
C Special requirements for bearings
If the radial size of the component is restricted and the radial load is very large, then use needle roller bearings.
D Economy
Common structure of the bearing is cheaper than the special structure of the bearing; ball bearings are cheaper than cylindrical or tapered roller bearings; spherical roller bearings are the most expensive. As long as the basic requirements are met, try to use spherical bearings. In the selection of bearing accuracy level, generally as far as possible with ordinary level.
(1) rolling bearing mounting and dismounting
general bearing due to the inner ring and journal with tighter, when mounting, large size bearings, can be used in the inner ring press on the method of pressure, so that it is tight set on the journal. Medium and small size bearings can be installed by hand hammer and sleeve. In order to improve the quality of assembly, can be used in the way of hot set, the use of thermal expansion and contraction phenomenon, the bearing in the hot oil heated after installation in the journal. In order to facilitate disassembly, the inner ring on the shoulder, the outer ring in the sleeve should leave enough height to put in the hook head of the disassembly tool.
(2) rolling bearing lubrication and sealing
①rolling bearing lubrication
Commonly used lubricant has two kinds of lubricating oil and grease. When the circumferential speed of the shaft is less than 4~5m/s, grease is generally used. The advantages of grease lubrication are: simple sealing structure, grease is not easy to lose, not affected by the temperature, add a grease can be used for a long time. However, the amount of grease filled into the bearing should be appropriate, generally fill the bearing cavity of 1/3 ~ 1/2. In the installation of bearings at the lubricating oil, such as gear reducer oil lubrication, or the whole machine has a centralized oil supply device, can also be used to lubricate the bearings. The grade of lubricant should be selected according to the requirements of the main parts, and the amount of lubricant should be appropriate. When using immersion lubrication, the height of the oil level should not exceed the centerline of the lowest rolling body of the bearing. When splash lubrication is used, the circumferential speed of the splash oil parts should not be less than 3m/s to ensure that there is sufficient concentration of oil mist.
②Rolling bearing seal
The role of the seal is to prevent dust, moisture, impurities, etc. invade the bearing, but also to prevent the loss of lubricant. There are many types of sealing devices, common forms are: felt ring seal; bowl seal; oil groove seal; labyrinth seal; rotary retaining ring seal; mixed seal.
Width series
Precision grade
Precision grade is expressed in Hanyu Pinyin letters, *** divided into 5 levels. That is: C (ultra-precision level) D (precision level) E (advanced) F (higher level) G (ordinary level). Generally more G-grade precision.
Bearing bore
Code 00 01 02 03 04 ~ 99
Bore (mm) 10 12 15 17 figures × 5
Bearings with bore less than 10mm and greater than 495mm, the standard is otherwise specified.
Bearing outer profile series (diameter series) - refers to the bearing inner diameter is the same, with different outer diameter and width.
100-Extra light series 200-Light narrow series 300-Medium narrow series 400-Heavy narrow series
500-Light wide series 600- Medium wide series
Medium wide series Medium-width series
Bearing type, indicated by 0~9
0-Single-row radial ball bearings 1-Double-row centripetal spherical ball bearings
2-Single-row centripetal short cylindrical roller bearings 3-Double-row centripetal spherical roller bearings
2-Single-row centripetal short cylindrical roller bearings 3-Double-row centripetal spherical roller bearings< /p>
4-Needle roller bearings 5-Spiral roller bearings
6-Single-row centripetal thrust ball bearings 7-Single-row tapered roller bearings
8-Thrust ball bearings 9 -Thrust centripetal symmetric spherical roller bearings
1, bearing overhaul
◆◆ The following is a bit of experience on rolling bearings of common sense:
One, on the bearings of the hot mounting method: because bearings in the production, there are impurities, metal shavings, and installation of the site is not necessarily clean, so in the oil groove under the steel grooves or on the paved metal mesh, and then put the bearing, so that the bearings, the oil grooves in the oil grooves below the steel or metal net, and then put the bearings. Metal mesh, and then put the bearings, so that the oil soaked through the bearings, bearings first heated in oil, heated to 50 ~ 60 ℃, the bearings up and down to turn a little bit, to remove impurities, domestic bearings to 90 ℃ to the outside, imported bearings to 100 ℃ to the outside (domestic bearings can not be more than 100 ℃, imported bearings can not be more than 110 ℃), the installation of a slight overload a little bit does not matter, the installation of the shaft, take the stick or Copper rod to knock the inner ring; when installing the set, knock the outer ring.
Second, bearing hot after installation: after installation, wrench the outer ring, rotate to the maximum angle, and then close the right. If there are impurities in the bearing, it is more difficult to set right. When falling to the bearing seat, use the plug ruler to plug the bearing and bearing seat clearance. Find the concentricity of the shaft, verticality. When there is no problem, close the box. (Gland experience method: close the box after tightening, screws and then turn 1/4 or 1/2 turn, the maximum 3/4 turn) close the box after a few people with a hand to turn the shaft, turn the best. Then refueling, a full, so that the oil mirror can not see the oil line, the oil release hole to release the oil, so that the oil line in the 1/2 to 2/3 between the oil level, once again to ensure that the oil tank is clean. Check no error can be turned on, rotate for ten minutes, stop the machine to check, are no error, and then formally open the machine.
Three, the role of the cage is guided. Copper keep good heat dissipation, mild deformation can be automatically restored. Steel keep bearings in the installation of attention, because it can not automatically recover, the installation requirements are very strict, but the service life is longer than the copper keep.
Four, maintenance issues, water circulation to do not lack of water. Often pay attention to the oil level, timely replenishment of oil, do not lack of oil. According to the oil quality is good or bad, timely oil change, new bearings need to be changed twice when the start of use of oil; downtime with gasoline or diesel fuel to wash the bearings, and then change the new oil. Lack of oil, oil full of bearing damage, the final result is the same. When the oil level is high, it cannot guarantee enough space for heat dissipation. When the oil level is low, it does not guarantee enough lubrication and heat dissipation.
Fifth, equipment damage manifested in the bearings, but not necessarily a bearing problem. Check the bearings first, and then expand to other. Any manufacturer does not guarantee that the bearing life, because the bearing from the production, installation, use, maintenance of all aspects should pay attention to, any one part of the problem is not. Fan bearings require fine use, because with a large load, and instantly over a lot of dust. For high-speed rotating equipment, a little dust can not.
Running bearings in the regular lubrication and maintenance
1, grease lubrication
Bearing re-lubrication is best implemented during the planned equipment shutdown, and regularly supplemented, at the same time, the old grease will be cleared away or through the drain air will be squeezed out of the old grease. The grease nipple should be wiped clean before adding fresh grease. If the bearing box does not have a grease nipple, the bearing box cover or end cap should be opened in order to remove the old grease, clean it up, and then replenish fresh grease of the same type.
2, lubricant lubrication
Regularly check the oil level and oil quality of the lubricant, in general, the normal oil level should be 1/2-2/3 of the equipment oil level window or labeled within the range. The oil replenishment method for the oil cup, the oil level shown only represents the oil replenishment capacity, while the bearing box oil level is to meet the operational requirements, the oil level in the oil cup is less than 1/4 of its total volume can be considered replenishment.
Check and replenish the oil method, take out a small amount of lubricant as a sample and fresh lubricant for comparison, the ability of the unit can be considered to carry out the oil quality test to ensure that the oil quality is qualified. If the sample looks cloudy, then it may be the result of mixing with water, which is often referred to as oil emulsification, at which time the lubricant should be replaced. If the sample darkens in color or thickens, it may indicate that the lubricant has begun to carbonize and the old lubricant should be completely replaced. If possible, flush the oil lines with fresh oil. When replacing the lubricant, make sure that the new lubricant is the same as the old lubricant and that it is replenished to the required level.
For oil bath lubrication systems, if the oil temperature is below 140°F (60°C) and the lubricant is not contaminated, changing the lubricant once a year is sufficient. If the oil temperature is between 60-100°C (140-210°F), the lubricant needs to be changed four times a year. If the oil temperature is 100-120°C (210-250°F), the lubricant needs to be changed once a month. If the oil temperature is above 120°C (250°F), the lubricant needs to be changed once a week.
While proper installation and maintenance are important for proper bearing operation, care must be taken to keep the bearings clean. Bearings must be protected from contaminants and moisture, and must have proper mounting and lubrication. In addition, the design of the bearing arrangement, the condition of the oil seal, the form of lubricant and the replacement cycle and specialized maintenance also plays an important role, must pay attention to.
Rolling bearing simple diagnosis
1, with the stethoscope method of rolling bearing monitoring
With the stethoscope method of rolling bearing working condition monitoring of the common tool is a wooden handle long screw spinner, can also use the outer diameter of φ20mm about the hard plastic tube. Relatively speaking, the use of electronic stethoscope for monitoring, more conducive to improve the reliability of monitoring.
1) rolling bearing normal working condition sound characteristics
rolling bearing is in normal working condition, running smoothly, briskly, no stagnation phenomenon, the sound harmony and no noise, can hear uniform and continuous "clatter" sound, or lower "boom" sound. The sound is even and continuous, or a low "boom" sound. The intensity of the noise is not great.
2) abnormal sound reflected in the bearing failure
(1) bearing uniform and continuous "sizzle" sound, this sound is generated by the rolling body in the inner and outer ring rotation, including irregular metal vibration with the speed of the sound has nothing to do. Generally, the amount of grease in the bearing is insufficient, and should be supplemented. If the equipment downtime is too long, especially in the low temperature in winter, bearing operation will sometimes issue "sizzling rustle" sound, which is related to the bearing radial clearance becomes small, grease work needle into the degree becomes small. Should be appropriate to adjust the bearing clearance, replace the needle into the new grease a little larger.
(2) bearing in the continuous "clatter" sound in the uniform periodic "ho Luo" sound, this sound is due to the rolling body and inner and outer ring raceway scars, grooves, corrosion caused by the spot. The sound cycle is proportional to the speed of the bearing. The bearing should be replaced.
(3) bearing discontinuous "terrier" sound, this sound is due to the cage or inner and outer ring rupture and cause. Must stop immediately to replace the bearing.
(4) bearing irregular, uneven "cha-ching" sound, this sound is due to bearing fall into the iron, sand and other impurities caused. The intensity of the sound is small, and there is no connection with the number of revolutions. The bearings should be cleaned, re-greased or oil change.
(5) bearing continuous and irregular "rustle" sound, this sound is generally associated with the inner ring of the bearing and the shaft is too loose or the outer ring and the bearing hole is too loose. Sound intensity is large, the bearing should be checked with the relationship, found that the problem is repaired in a timely manner.
(6) bearing continuous ear-piercing whistling sound, this sound is due to bearing lubrication or lack of oil caused by dry friction, or rolling body local contact is too tight, such as inside and outside the ring raceway skewed, the bearing inner and outer ring with the tightness of the situation caused by. Should be timely inspection of the bearing, find out the problem, symptomatic treatment.
3) the use of electronic stethoscope monitoring requirements
(1) listening process, as far as possible to choose the same type of monitoring points, or working conditions close to the monitoring point of sound comparison, found that the anomaly should be viewed as a defective, in-depth inspection must be carried out. For a single device, in order to overcome the shortcomings of non-comparability, you can monitor the point in the normal state of the sound recording, as a comparison of the basis for future monitoring.
(2) to correctly select the part of the monitoring point, the direction of the vibration to be measured should be consistent with the sensitive direction of the sensor, so that the measurement direction for the direction of the maximum intensity of vibration. The sensor and the measured surface should be at right angles, the error is required to control within 10 °.
(3) Requirements for the measurement surface is clean and flat, so that there is no rust, no paint, and will be under the concave part of the grinding, so that it is smooth and flat.
(4) The measuring force pressed to the probe is 10-20N.
3, with the measurement method of rolling bearing monitoring
By measuring the temperature rise in the bearing operation, it is generally difficult to monitor the bearing appeared fatigue spalling, cracks or indentation and other localized damage, especially in the early stage of the damage is almost impossible to find any problem. When the bearing in long-term normal operation, the phenomenon of temperature rise, generally reflects the problem has not only been quite serious, and will develop rapidly, resulting in bearing damage failure. At this time, intermittent monitoring often results in leakage. If the temperature of the bearing is found to be more than 70-80 ℃ in the monitoring, it should be stopped immediately for inspection.
For the new installation or readjustment of the rolling bearing, through the temperature measurement method, monitoring its temperature rise in the specified time, can judge the bearing installation and adjustment quality, especially the gap is too tight when the temperature rise will be too high phenomenon. Problems found in time to adjust, is conducive to extend the service life of rolling bearings.
Four, reducer class
Reducer is a closed in the box transmission device, which consists of gears or worm gears, etc., can be used to change the rotational speed between the two shafts and torque, in the project is widely used. Reducer is mainly composed of box, gears, shafts, bearings and so on.
The case of planetary reducer is mostly non-dissected integral type, which is easy to ensure the machining accuracy, but the assembly is more difficult.
Rolling bearings are usually used in the gearbox, and the bearing clearance is adjusted by bearing caps with shims. In order to facilitate the view of the gear mesh situation and to the case of lubricating oil injection, in the case of the cover with a view hole, the view hole has a view hole cover cover. View hole cover is often placed on the breathable plug, when the air in the box due to the temperature rise and expansion, can be discharged from this.
The lubrication of the reducer is an important condition to ensure the normal work of the reducer. It can reduce the friction and wear on the gear and bearing contact surface, but also can dissipate heat, rust and reduce noise. Reducer gears commonly used lubrication is the gear bath in the oil pool, so that the lubricant is brought to the meshing surface for lubrication, in order to prevent the churning of the power loss is too large, the gear immersed in the oil pool depth should not be too deep. Usually immersed in 1-2 tooth height. Low-speed gear top circle from the bottom of the box should not be less than 30-50mm or so, in order to avoid the bottom of the pool sludge debris is brought to the tooth surface.
When the gear speed is high, the lubricant on the tooth ring is thrown to the box wall, and due to the splash and the formation of oil mist, and the bearing can be directly lubricated by the oil mist. When the gear speed is low, the oil thrown to the box cover can be collected through the oil groove opened on the box seat and flow into the bearing for lubrication.
When the circumferential speed of the gear is too high, it must be used to spray oil circulation lubrication, that is, the lubricating oil from the oil pump through the oil pipe to the need to lubricate the lubrication. If the gear speed is very low, grease can be used to lubricate the bearings.
In order to check whether the lubricant in the box is the right amount, should be equipped with oil markers. There are also oil drain holes and oil plugs near the bottom of the box.
◆◆Cycloid reducer
The whole transmission device can be divided into three parts: input part, deceleration part and output part. On the input shaft, there is a double eccentric sleeve which is dislocated by 180°, and on the eccentric sleeve, there are two roller bearings called swivel arms to form H mechanism, and the center holes of the two cycloid wheels are the races of the swivel arm bearings on the eccentric sleeve, and the cycloid wheels mesh with a set of annularly arranged needle teeth on their gears, so as to form the internal mesh reducer which has the difference of teeth as a single tooth (for the sake of reducing the friction, in the reducer which has a small ratio, there is a needle tooth sleeve on the needle teeth). (in order to reduce friction, in the speed reducer with small ratio, the needle teeth with needle teeth sleeve).
When the input shaft rotates with the eccentric sleeve for one week, due to the characteristics of the tooth profile curve on the cycloid wheel and its restriction by the needle teeth on the needle gear, the motion of the cycloid wheel becomes a planar motion with both rotation and self-rotation, and when the input shaft rotates for one week, the eccentric sleeve rotates for one week, and the cycloid wheel rotates through one tooth in the opposite direction to get the deceleration, and then with the help of the W output mechanism, the low-speed rotation of the cycloid wheel will be transmitted to the output shaft through the pin. Then, with the help of W output mechanism, the low-speed rotation motion of the balance wheel is transmitted to the output shaft through the pin, so as to obtain a lower output speed.
The main parts are made of high carbon steel and quenched (HRC58-62) for high strength.
Commonly used transmission ratios are 6, 9, 11, 17, 23, 29, 35, 43, 59, 71, 87, etc., and its eccentric wheel teeth for the transmission ratio plus 1, but the speed ratio of 35 or more, after conversion, its teeth halved, two pieces of the cycloid wheel in the assembly, the marking must be staggered by 180 ° and the word face up.