Successful installation and commissioning of high-precision double-row cross roller bearings

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At the beginning of this month, Luoyang Hengguan Bearing Technology Co., Ltd. (hereinafter referred to as Hengguan Bearing) provided a customer in Zhejiang with high-precision double-row crossed cylindrical roller slewing bearings for machining rotating platforms. All indicators have met or exceeded At the request of the purchaser, it was successfully delivered to the purchaser; the installation and commissioning has been successful, and the banknote printing mode is turned on for the purchaser.

 

This slewing ring bearing belongs to the rare double-row cross-roller structure on the market. It is different from the conventional single-row four-point kick structure, double-row ball structure, single-row cross roller structure, and three-row cylindrical roller structure on the market. The big structure is completely different.

 

The service tenet of Hengguan Bearing is to quickly respond to customer needs, provide excellent technical solutions in a shorter time, and solve engineering problems safely and effectively for customers. This product is an upgraded product of the first generation of bearing products. According to customer feedback, the first generation of bearing products have poor rigidity after being installed and deformed after being stressed, causing the equipment to lose accuracy. After receiving the customer’s consultation call, our company quickly arranged an engineer to connect with it. , Carry out all-round technical communication and diagnosis. Starting from the customer’s working conditions, load-bearing, speed, use requirements, etc., after several modifications, a very difficult double-row cross-roller structure was selected. This new double-row cross-roller structure has good rigidity, heavy bearing capacity, and is not easy to deform. Such advantages have overcome the shortcomings of the first generation of single-row cross rollers. The product was scheduled for 40 days and shipped smoothly; when the final product was inspected, the inner and outer ring end pendulums were 0.015, the clearance is 0, the diameter pendulum is 0.02, and the outer diameter is 1520mm; our company has overfulfilled the task and all the parameters are all Has met or exceeded the customer’s confirmed drawing requirements. At present, the product has been delivered to the customer, and has been successfully installed and commissioned and put into operation.

 

Innovation is the driving force of development. To grasp innovation is to grasp development, and to seek innovation is to seek the future. Hengguan Bearing continuously carries out technological innovation, and always insists on giving back to customers with dedicated service. We have the courage to challenge every technical problem, and cooperate with today’s ever-changing industrial production needs 24 hours a day, with fast response and flexible and thoughtful service to ensure effective solutions and excellent quality assurance.

 

Hengguan Bearing’s all efforts are to provide customers with better products and service experience, and create greater value for customers. The mutual benefit and win-win situation of both customers and us are the root of the company’s long-lasting prosperity! Hengguan Bearing, intelligently creates the future, and is only a provider of excellent products and dedicated services!

The production of high-speed silent slewing ring bearings was successfully completed

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Recently, the high-end slewing bearing for medical CT machine designed and produced by our company for Middle East customers has been successfully rolled off the production line, and all the indicators of the finished product have passed the inspection.

For the CT machine special slewing bearing bearing, we and the Iranian CT machine manufacturer, after more than a month of full technical communication, understand the various technical requirements of the customer, and calculate the bearing capacity and service life according to this requirement. Technical parameters, confirmed the production drawings. This product has an outer diameter of 1180mm and an inner diameter of 980mm. It has a toothless four-point contact ball slewing bearing structure with P5 accuracy. It is a high-end precision slewing bearing; and because it is medical, it has extremely high requirements for noise reduction.
High-speed silent slewing bearing 　　According to the actual working conditions of customers, our technical engineers actively improve the product processing technology, and strive to make products that meet the actual needs of customers. First, the 42CrMo quenched and tempered material is used to make the material performance better and more stable, which guarantees the product quality from the source; secondly, the product raceway and appearance are comprehensively polished to ensure high product precision; thirdly, for the product’s silent requirements, A special segmented nylon cage device is used to lock the ball in the cage pocket while ensuring that the steel ball can rotate freely, thereby reducing the noise impact caused by the free movement of the cage in the raceway. Reduce rotating noise. Through the above efforts, we ensure that the finished products of the slewing ring meet various technical requirements.

After the finished product came out, after trial assembly test, it has fully met the requirements of the confirmed drawings of both the customer and us, and the rotation is flexible and light, and the rotation is silent. At present, this product is already on the way to customers. I believe that made in China will amaze foreign customers and win glory for the country! Hengguan Bearings actively responds to the call of President Xi and develops manufacturing in China towards high, precise and cutting-edge development!

The vision of “Let the world fall in love with Made in China” is not only a slogan, but also implemented in practical actions. It requires countless Chinese companies to constantly challenge themselves technologically and seize the right to speak for China in the core field of manufacturing. In the era of high-tech industry, only Chinese manufacturing can win the “tough battle” and truly realize “Let the world fall in love with Chinese manufacturing!” We Hengguan people carry this great dream and actively practice it! The road is long and long, Hengguan people will persevere in pursuit! May you and I walk along this great journey…

What are the characteristics of the cross wave roller slewing bearing?

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Roller slewing bearing are one of the main types of crossed roller bearings. They are composed of two races, optional rollers at the cross-rotating position, retaining (isolation block), sealing device and other components. Such as the waist rotation of robots, automated robots require precise rotation of rotating disks, welding station turntables, large-diameter rotating disks, large-diameter towers, and automobiles and other mechanical equipment. Next, let’s follow the editor to understand the characteristics of inertial roller slewing bearings.

1. Loads in all directions can be downloaded

The cross-rolling roller slewing bearing has only one row of rolling elements, but the rolling elements are short rolling elements, and the surrounding rollers roll at 90° cross. There are several raceways in the inner and outer rings, including the problem of which rollers and rollers are axial forces. , Adsorption simple axial force, sponge adsorption force, adsorption force and overturning ability. The length of the roller should be 0.5~1mm longer than its diameter. Integral structure, good embedded. .

2. Isolation block

Cross-rolling roller slewing bearings can be equipped with spacers or without spacers. Many foreign countries used in construction machinery can not be equipped with isolation blocks.

3. Adjustable clearance

Most of the cross-rolling roller bearings are made of parts to facilitate the installation of rolling elements and adjustment of the clearance. But there are also integral ones. Like four-point contact balls, the rubber filling holes are equipped to fill the rollers, and the options are used to adjust the axial movement. The rollers also need to be free after installation. There is always space between the rollers. When the full load direction is usually about 0.5.

4. Increase of effective compressed air

The internal structure of the cross-roller slewing bearing adopts the rollers to form a 90° cross-arrangement, and the rollers are separated from each other. The retainer isolation or isolation block can prevent the rollers from observing each other and effectively prevent the rotation lock. The increase. In addition, there will be no contact between the two rollers.

Single row cross roller slewing bearing

5. Centrifugal rotation

For non-standard roller bearings that cross at the same time, the outer circumference is a divided structure, and the gap can be adjusted. Even if preloading is applied, it can obtain a rotational movement.

6. Simple operation

After the divided inner ring or outer ring is installed with rollers and spacers, it is fixed with the cross roller ring to prevent complete separation, so the operation when installing the roller ring is very simple.

7. Prevent the roller from falling sideways

The cage eliminates the interconnection between the rollers and prevents the rollers from falling sideways, so that a stable rotating column can be obtained.

8. One place raises the air

Different from the use of double row thin angular contact ball bearings, the columns are arranged in a vertical cross, so the load in all directions can be controlled with a single cross roller ring, and the expansion is 3 to 4 or more.

The above is an introduction to the characteristics of wave roller slewing bearings. In fact, the characteristics and applications of structural roller slewing bearings are basically the same as those of four-point contact ball slewing bearings, except that the rolling elements are made of steel ball rollers, the rolling elements and the outer ring. The contact changes from point contact to line contact.

Characteristics of stainless steel slewing ring

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Nowadays, industrial technology is developing more and more rapidly, and various stainless steel materials are also being used in large quantities at this time. Industrial production cannot do without mechanical equipment, so many mechanical equipment cannot do without stainless steel bearings. Good stainless steel slewing ring bearings can be said to be an important guarantee for the production of mechanical equipment. Many friends are not particularly familiar with stainless steel slewing bearings. Next, the editor will talk about the characteristics of stainless steel slewing bearings for everyone to learn and understand.

1. The material of stainless steel slewing ring is special

Generally speaking, slewing bearings generally use two materials, 50Mn and 42CrMo, but stainless steel should be used for special purposes. The ferrules and rolling elements of stainless steel slewing bearings often use 9Cr18Mo, 9Cr18, 4Cr18 materials.

2. Excellent corrosion resistance

The sales volume of stainless steel bearings on the market is still considerable. You must know that stainless steel bearings have many advantages, so their durability is also very strong. First of all, good corrosion resistance is a major advantage of stainless steel bearings. Since this type of bearing has passed the extreme tests of high temperature and low temperature, it will have stronger corrosion resistance.

3. Washing resistance

Stainless steel bearings are also very resistant to washing. After we have used the bearings for a period of time, there is no problem in removing them for washing. Due to the water resistance of stainless steel bearings, rust will not appear even if they are washed in water.

4. Long service life

Because the material corresponding to the stainless steel bearing is the international standard stainless steel material, regular maintenance during daily use can extend its service life.

5. Wide range of use

Compared with slewing bearings of common materials, stainless steel slewing bearings have stronger rust and corrosion resistance, and are generally used in some special working conditions, such as underwater, wet seaside and other working conditions. Stainless steel slewing bearings are commonly used in food machinery, environmental protection equipment, medical equipment, and underwater operation tools.

The above is an introduction to the characteristics of stainless steel slewing bearings. Choose the appropriate dust cover and lubricant. Stainless steel slewing bearings can be used in an environment of -60℃~+300℃. Because of its high mechanical strength, large load capacity, and beautiful appearance, stainless steel slewing bearings are widely used in food processing, medical equipment, pharmaceutical machinery, nuclear industry projects and other equipment.

Luoyang Hengguan Bearing Technology Co., Ltd. mainly produces slewing bearings in the diameter range of 50-10000mm. Among them, stainless steel slewing bearings are a major characteristic product of Hengguan Bearings. At present, they have been equipped with stainless steel slewing bearings for many projects at home and abroad, and they are all very successful. Cases, well received and praised by customers.

How to install the slewing bearing of large amusement rides？

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Slewing ring is a large-scale bearing often used in modern machinery and equipment, which can bear large axial and radial coincidence and overturning moments at the same time. At the same time, it is also an important part of the large-scale amusement equipment slewing system, which bears various loads during the operation of the equipment. In addition to calculation and selection, attention must be paid to its correct installation and use. The harm caused by installation errors and improper use to amusement facilities can also not be ignored. So how to install the amusement slewing ring? Next, let’s follow the editor to understand it.

The form of movement of amusement facilities mainly includes rotational movement, linear movement, and a compound movement of rotation and linear movement. Rotational motion is the main form of movement of amusement equipment, such as carousel, self-controlled aircraft and high-altitude flying, etc. The main component that realizes the rotational motion is the slewing bearing.

1. Installation form of amusement equipment slewing bearing

In the field of amusement equipment, there are two ways to install slewing bearings: horizontal installation and vertical installation.

Flying tower and self-controlled aircraft amusement facilities are characterized by rotating around the central axis. Flying tower amusement facilities include high-altitude flying, head-shaking flying chair, etc., and self-control aircraft amusement facilities include self-control aircraft, big octopus, etc. The installation form of the slewing bearing in this type of equipment is horizontal installation.

The characteristics of the operation of the amusement facilities of the ferris wheel are that it rotates or swings around a horizontal axis. The amusement facilities of ferris wheel include screaming, big pendulum, etc. The installation form of the slewing bearing in this type of equipment is vertical installation.

Slewing ring

2. Installation of slewing ring

1. Before installing the slewing ring, check the mating surfaces and clean the two mounting surfaces to prevent any solvent from contacting the sealing belt or entering the raceway. Do not paint the sealing belt.

2. The slewing bearing mounting seat components should have sufficient rigidity, the contact surface of the bearing must be cleaned, there should be no lubricating oil and must be kept dry, and the mating surface should be machined to ensure that the two mating surfaces and the two ends of the slewing ring are in the whole Full contact on the circumference, reaching the flatness and inclination required by the relevant standards.

3. The bolts selected for the slewing bearing are high-strength bolts, and the length of the installation bolts shall not be less than 5d (d is the thread diameter).

4. The slewing bearing connection of amusement equipment adopts high-strength bolts above 8.8. Full-threaded bolts cannot be used. The anti-loosening method is a double nut method. The two nuts should be the same. At the same time, they should be matched with flat washers to increase the supporting area and prevent the installation surface hardness. It is not high to cause plastic deformation of extrusion, which is beneficial to maintain the reliability of pre-tensioning. Since the spring washer will destroy the centrality of the bolt’s force, reduce the pressure area and rigidity of the nut on the connecting parts when passing, and reduce the connection strength of the bolt. Under no circumstances should the spring washer be used.

5. When installing, the slewing bearing should be positioned radially first, and then the installation bolts should be tightened crosswise, that is, star-shaped installation, symmetrically and continuously in the 180° direction, and then re-tighten it again to ensure that the bolts on the circumference have the same pre-tightening. Force, and check the rotation of the turntable slewing bearing. In order to increase the reliability of the connection, the prestress of the tightened bolt should be 70% of the yield strength of the bolt material.

6. In order to ensure smooth rotation of the turntable slewing bearing, the gears should be checked for meshing before the mounting bolts are completely tightened. The small value of the tooth side clearance is generally 0.03 ~ 0.04 X m (modulus), after the slewing bearing is finally tightened , The gear tooth clearance of the pinion on the entire circumference should be re-checked.

The above is the answer on how to install the slewing ring of amusement equipment. Luoyang Hengguan Bearing is a comprehensive entity enterprise of slewing ring/slewing bearing that integrates design, research and development, production, sales and service. Products are widely used in new energy, medical, amusement, automation, lifting, construction, mining, metallurgy, ports, textiles, ships, environmental protection, aerospace, wind power and other fields. In addition, it also implements personalized optimization design and customized flexible production for different customers to meet customer needs. Friends in need are welcome to call for detailed consultation.

Analysis on the reasons of Grease Leakage of Pitch Bearings of Wind Turbine

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With the increase of the operating time of the wind turbine, the sealing ring of the pitch bearing is gradually aging, the lubricating grease is gradually deteriorating, the waste grease is not drained smoothly and the pitch bearing is not completely rotated, resulting in uneven internal pressure, which will lead to the pitch bearing sealing ring. There are different degrees of grease leakage. If it is not handled in time, it may cause poor lubrication of the pitch bearing, thereby affecting the service life of the pitch bearing and the wind turbine. Today, the editor will conduct a detailed analysis of the causes of grease leakage in the pitch bearing of wind turbines for everyone to learn and understand.

 

The internal structure design of the pitch bearing is unreasonable

 

1, channel structure

 

The design of the pitch bearing channel affects the fluidity of the grease in the groove inside the bearing. Under normal circumstances, the variable pitch bearing is filled with grease from the grease hole. The pressure difference required to discharge the waste grease from the grease hole is less than the pressure value that the seal ring can withstand, and at the same time is greater than the resistance value of the grease flow, the seal ring No fat leakage. The required pressure difference is closely related to the resistance of the grease to flow. A small resistance requires a small pressure difference, and a large resistance requires a large pressure difference. If the design of the internal channel of the pitch bearing is unreasonable, the grease flow resistance will be large, which is not conducive to the uniform distribution of the grease and the internal pressure, and the grease cannot enter the grease discharge hole smoothly, resulting in poor grease discharge, resulting in grease at the seal ring overflow.

 

2, size and distribution of lipid pores

 

The grease injection holes and grease discharge holes of the variable pitch bearing should be distributed at reasonable intervals to ensure that the bearing can be smoothly injected with new grease and discharged. The distance between the adjacent grease injection hole and the grease discharge hole should be moderate. If the distance is too short, the pressure of the grease injection hole will be higher and the pressure of the grease discharge hole will be lower during grease filling, and the newly added grease will be easily discharged from the grease discharge hole; If the length is too long, the seal ring will bear greater local pressure when adding grease, which will easily lead to grease leakage. In addition, the cross-sectional diameter of the grease discharge hole is too small, the diameter of the grease collection bottle connected to the grease discharge hole is too small, and the distance between two adjacent rows of grease holes on the bearing is too large, which will also increase the resistance of grease discharge, resulting in poor grease discharge. Smooth, so that the internal pressure of the pitch bearing is too large, resulting in grease leakage.

 

Poor sealing

 

  1. Aging and wear of the sealing ring

 

Most of the pitch bearings use nitrile rubber seals, which will age after long-term use. The aging rate is related to the acrylonitrile content in the nitrile rubber, the rubber content of the formula, the antioxidant and the use environment. In general, the nitrile rubber The service life of the sealing ring is 5~10 years. The pitch bearing adopts a contact seal. During operation, the seal ring contacts the friction surface of the seal. As the running time increases, the seal ring will gradually wear out, resulting in a decrease in sealing performance and insufficient pressure on the seal ring. Grease may be removed from the seal ring. Leakage.

 

2, the seal ring structure design is unreasonable

 

Pitch bearings generally use double-lip seals. The outer lip can block moisture, dust and other harmful substances from entering the inside of the bearing, and the inner lip can prevent grease leakage. If the seal ring structure design is unreasonable, the sealing effect will be affected after installation, and the seal ring may be deformed after the pitch bearing is operated, resulting in insufficient sealing ability or sealing failure, and the grease is easy to leak.

 

  1. Improper installation and maintenance of the seal ring

 

Failure to install or maintain according to the process will result in uneven force on the seal ring. Poor interface bonding during the installation of the seal ring will cause the seal ring interface to break. After the subsequent pitch bearing grease injection operation, the seal ring is prone to bulging and warping (Figure 1 ) And the phenomenon of fracture, so that the grease will overflow from the gap, warpage and damage of the sealing ring.

 

4, the sealing ring is squeezed and damaged

 

When installing or maintaining the blades of wind turbines, hydraulic tensioners need to be used to apply torque to the connecting bolts between the blades and the pitch bearing. The distance between the connecting bolts and the sealing ring is relatively short, and the extension head of the hydraulic tensioner has a larger overall size. The stretching head is easy to press on the sealing ring to cause serious damage to the sealing ring, as shown in Figure 2. The subsequent operation of the pitch bearing may cause deformation and tearing of the sealing ring, resulting in a large amount of grease leakage.

 

Improper selection of grease or unreasonable setting of lubrication system

 

  1. Improper selection of grease

 

The choice of grease usually refers to the actual working conditions of the pitch bearing, and also needs to consider the consistency of the grease and the type of additives. The consistency of the grease is closely related to the ambient temperature. Every time the ambient temperature drops by 5 ℃, the consistency will double and the fluidity of the grease will deteriorate. If the consistency of the grease is not appropriate or the pressure resistance is insufficient, subsequent use is likely to occur The solidification phenomenon blocks the grease system, causing the grease to not be discharged normally and leak from the sealing ring, as shown in Figure 3.

 

2. The amount of grease injection and the setting of the centralized lubrication system are

unreasonable

 

The pitch bearing needs to be filled with a certain amount of grease before operation. The filling amount is about 60% to 80% of the inner space of the pitch bearing. Generally, the filling amount is about 70%. There are also individual pitch bearing suppliers to ensure sufficient Choose 80% filling amount for lubrication.

 

Most wind turbines at home and abroad use centralized lubrication systems to fill the pitch bearing with grease. Some wind turbine manufacturers use manual and regular grease filling to further reduce the maintenance cost of the pitch bearing. Both of these two methods of refilling grease have shortcomings: the grease injection amount and grease injection period for manual regular grease injection are often empirical data, and there is a large deviation from the actual grease required for the pitch bearing. The grease injection volume is usually In this case, the lubrication time of the pitch bearing cannot be guaranteed. In addition, about 80% of the grease may be added to the pitch bearing before leaving the factory, which will easily cause a large amount of local grease to accumulate in the pitch bearing channel. ; The centralized lubrication system adopts automatic grease injection method to make the bearing lubrication more adequate. Although the lubrication time and grease injection uniformity of the variable pitch bearing are guaranteed, the centralized lubrication is performed when the variable pitch bearing is not running or the unit is shut down for a long time The system continues to inject grease according to its preset fixed program, which is also likely to cause a large amount of local grease accumulation in the pitch bearing channel.

 

Under normal conditions, the sealing pressure of the sealing ring of the pitch bearing is about 2.8×105 Pa. The grease injection pressure required when the pitch bearing is stationary and not working is about (2.5~2.8) x105 Pa. The grease injection pressure required when the pitch bearing is running is only It is about 0.6 x105 Pa. Due to the poor fluidity of the grease used in the pitch bearing, the large accumulation of grease caused by the above two kinds of grease injection methods will increase the pressure of the grease channel in the pitch bearing channel, thereby increasing the injection required during grease injection. Fat pressure. When the grease injection pressure is greater than the sealing pressure of the pitch bearing seal ring, the grease will leak from the pitch bearing seal ring under the action of the grease injection thrust.

 

In addition, if the air in the pressure pump or grease pipe of the centralized lubrication system is not completely emptied, the air will enter the pitch bearing channel along with the grease, resulting in excessive local pressure in the channel. When the pressure is greater than the pitch bearing The sealing pressure of the sealing ring will open the sealing ring, causing serious grease leakage.

 

  1. Improper collection of waste fat

 

At present, the waste grease collection of pitch bearing of wind turbines generally adopts the method of installing grease collecting bottles in several waste grease discharge holes distributed on the circumference of the bearing. When new grease is added, the new grease squeezes the waste grease into the waste from the inner cavity of the bearing. Grease drains out of the small holes and drains into the fat collecting bottle, which needs to be cleaned regularly. In fact, as the running time of the pitch bearing increases, the waste grease collection effect is not good, and it is easy to leak grease.

 

The above is about the analysis and introduction of the reasons for the grease leakage of the pitch bearing of the wind turbine. As an important component of the wind turbine, the pitch bearing is used in a harsh environment, high maintenance costs, and complex forces, and directly affects the continuity of the entire pitch movement. Stability and accuracy. Therefore, in order to ensure the reliability of the life of the pitch bearing, the pitch bearing needs to be well sealed and lubricated to avoid grease leakage.

Analysis of the causes and preventive measures of bearing cracks in grinding processing

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Mechanical grinding is a method of manufacturing a common metal cutting, the bearing processing industry also been widely used, the bearing parts of heat hardening, or reticular cracking may occur more rules during grinding arrangement of small cracks, known as grinding cracks, it not only affects the appearance of bearing parts, more importantly, also directly affect the quality of the bearing parts. This paper analyzes the causes of bearing parts produced grinding cracks in the grinding process, then take preventive measures, so as to effectively prevent the generation of grinding cracks.
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First, the reasons bearing grinding cracks
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Generating bearing grinding cracks caused by the grinding heat, the surface temperature of the bearing up to 800-1000 ° C or more grinding. Tissue quenched steel is of martensite and residual austenite certain number of them are in a expanded state (without tempering). With increasing expansion and contraction of martensite steel carbon content increases, the steel grinding cracks generated surface of the bearing is particularly important. Effect of grinding heat of retained austenite in hardened steel that is subject to decomposition during grinding, gradually transformed into martensite, martensite this renewed focus on the surface of the part, causing local expansion of the bearing surface, increased parts of the surface stress, stress concentration resulting in grinding, will continue to accelerate the grinding surface of the grinding cracks produced; in addition, the nascent large Chuai martensite, grinding easily accelerate the production of grinding cracks.
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On the other hand, grinding when the grinding machine parts, parts of both pressure and tensile force is, contributing to the generation of grinding cracks. If the cooling is insufficient at the grinding, since the heat generated during grinding, the grinding surface of the sheet sufficient to re-austenitization, quenching and then quenched again into martensite, so that the surface layer of additional stress in the organization, coupled with the amount of heat generated by the grinding surface of the bearing temperature rises fast, fast cooling, which is superimposed the stress and thermal stress may lead to the grinding surface of the grinding cracks generation.
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Second, it characterized in bearing grinding crack
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Usually the grinding cracks significantly different quenching cracks, cracks occur only in the grinding surface of the grinding, shallow, and substantially uniform depth. Lighter grinding cracks perpendicular or nearly parallel to a line perpendicular to the grinding direction and are regularly arranged strips crack, which is a kind of cracks, crack more severe form of tortoiseshell (closed network like), a depth of approximately 0.03 ~ 0.15ram, with obvious cracks after acid etching, which is the second crack.
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Third, grinding cracks Prevention
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From the above analysis of the root cause to know that the generation of the grinding cracks are in a quenched martensite expanded state, the presence of stress. To reduce or eliminate such stress, the stress to be tempered i.e. quenching, tempering is performed, waste of time must be more than 4h. With increasing tempering time, the possibility of grinding cracks decreases. In addition, bearing in rapidly heated to about 100 degrees C and rapid cooling will crack. To prevent cold cracks, the part should be tempered at about 150 to 200 degrees Celsius, if heated to 300 degrees Celsius to continue bearing surface shrinkage cracks again, to prevent the generation of cracks, the bearings should be tempered at about 300 degrees Celsius. It is noteworthy that, bearing around 300 degrees Celsius tempering the hardness will drop, something should not be used. Is produced through a tempering still grinding cracks, which can be tempered or secondary artificial aging treatment, this method is very effective.

Slewing ring

It produces grinding cracks due to heat caused by grinding, so reducing the grinding heat is the key to solve the grinding cracks. Wet milling method is generally employed, but in any case the injection coolant, the coolant no method to arrive at the grinding surface grinding, grinding heat and therefore can not reduce the grinding point. Coolant only part of the grinding point of the grinding wheel and grinding after cooling being passed instantaneously, while the quenching effect of the cooling liquid to make the grinding point. Thus increasing the amount of coolant is one of the main measures to minimize the grinding zone of the grinding heat. If dry milling process, grinding feed less, grinding cracks can be reduced. However, this method is not very significant, and dusty, affecting the work of a bad environment, should not be taken.
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Selection softer durometer, coarser sand to the grinding wheel, grinding heat can be reduced. However, coarser particles can affect parts of the surface roughness, high surface roughness for the part, can not use this method, and therefore subject to certain restrictions. The crude fraction, grinding, selection of both coarse particles coarser soft grinding wheel, the grinding facilitate strength, improve efficiency, and then be fine-grained grinding wheel, grinding feed amount is small. Two points were roughing and finishing, this is the ideal method.
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Self-sharpening properties of a good choice of abrasive wheel, the grinding wheel surface timely removal of waste material, reducing the grinding feed, increasing the number of grinding table speed is reduced, which is an effective way to grinding cracks is reduced.
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The rotational speed of the grinding wheel and part of one of the factors is the main, large wheel rotation runout, ran large parts are grinding cracks incentives. Increase in time accuracy of the grinding wheel and the rotary part so as to eliminate the grinding cracks caused by various factors as much as possible.
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Fourth, the method of preventing the surface of the bearing steel grinding cracks
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In grinding, the grinding cracks generated surface bearing steel, the main method for preventing:
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① reduce grinding heat to solve the grinding cracks.
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② points coarse, fine grinding, both coarse particles selected coarse grinding soft grinding wheel.
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③ Selection good performance since the sharp abrasive wheel, the grinding wheel surface timely removal of waste material, reducing the grinding feed, increasing the number of grinding table speed is reduced.
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④ increase in time accuracy of the grinding wheel and the rotating parts so as to eliminate cracks caused by grinding possible.
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These are the bearings on the causes and preventive measures of cracks in the grinding process analysis reports, I hope you can help look after. Luoyang permanent crown diameter slewing bearings are mainly production of 50-9800mm / wheel bearings and various high-precision rotary bearing, a large thrust ball bearings, bearings and other non-standard shaped products, precision covering P0, P6, P5, P4 four grades, the product type comprises a single row four-point contact ball structure, cross-cylindrical roller structure, a triple-row cylindrical roller structure, a double structure volleyball, the ball joint structure of columns, thin-walled flange structure, large thrust ball structure. Welcome to the needs of friends to call detailed consultation.

What are the requirements for the packaging of bearings?

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For bearing products, packaging is very important, not only to prevent rust, but also to protect the bearing from bumps during transportation and damage to the bearing. Bearing packaging is divided into inner packaging and outer packaging. So, what are the requirements for the packaging of bearings?

First, the inner packaging of the bearing

After the bearing is manufactured and passed the inspection, it will be cleaned and anti-rust treated, and then put into the inner packaging to achieve the purpose of waterproof, moisture-proof, dust-proof, shock-proof, maintain the quality and accuracy of the bearing, and facilitate the use and sale. .

1. The inner packaging of the bearing is divided into three categories according to the anti-rust period

① Short anti-rust period packaging

The anti-rust period is 3-6 months, which is suitable for bearings that are shipped to the same subscriber in large quantities and put into use in a short period of time. The two parties have agreed to use simple packaging based on the principle of ease of use.

② General anti-rust period packaging

The anti-rust period is one year, suitable for general-purpose bearings.

③ Long anti-rust period packaging

The anti-rust period is two years, suitable for special and precision bearings.

2, bearing inner packaging material requirements

There are polyethylene plastic tube (box), kraft paper, plain and wrinkled polyethylene composite paper, paper box, polyethylene or polyethylene plastic film, nylon fastening tape or plastic woven fastening tape, waterproof high-strength plastic tape, burlap bag, etc. . All of the above materials need to ensure that the corrosion resistance test of the material is qualified.

3, the requirements of bearing inner packaging method

①Miniature bearing

Every 10~15 sets of bearings are packed into a plastic tube, and every 5~10 plastic tubes are packed into a carton (or bag or roll pack).

②Medium and small bearings

Multiple sets of bearings are wrapped with polyethylene film, kraft paper or polyethylene composite paper for external use; multiple sets of bearings are packed into a plastic tube (box); single set of bearings is packed in polyethylene film bags, folded or sealed before repacking Into a paper box.

③Large bearing

Pack it in a single set of polyethylene film or polyethylene composite paper, and then put it into a carton; use a polyethylene film bag, pack the single set of folded bag openings, and then put it into a carton; put the single set into a special plastic box; Three-layer wrap-around packaging: polyethylene film tape or composite paper tape for the inner layer, fastening tape for the middle layer, and waterproof permeable plastic tape for the outer layer.

④Extra large bearing

Single set of three-layer wrapping packaging (same as above).

Single-by-four-layer wrapping package: After the above-mentioned three-layer wrapping package, the outer layer is wrapped with a layer of linen tape.

For separable tapered roller bearings with outer diameter ≥150mm, the inner and outer components should be lined with polyethylene film before packaging, or the inner and outer components should be packaged separately. For interchangeable cylindrical roller bearings with an outer diameter of ≥150mm, because the complete package is easy to be damaged, the inner and outer components can generally be packaged separately.

Secone. Standards for bearing outer packaging requirements

1. General materials and requirements for outer packaging of bearings

① Double corrugated boxes, the total weight (gross weight) of each box does not exceed 25kg, and the outside of the box is bound with plastic strapping.

② Nail board box (wooden box), the total weight of each box does not exceed 30kg, and the outside of the box is bound with blue steel tape.

③ Calcium plastic corrugated box, the total weight of each box does not exceed 25kg, and the box is bound with plastic strapping.

When packing bearing products with inner packaging into the box, plastic bags or plastic films should be lined in the box first; if there are gaps in the box, it should be filled with corrugated paper blocks, paper scraps and other dry materials.

2, pay special attention

It is especially important to emphasize that due to the heavy weight of large bearings, packing straps should be added to the packaging box to ensure the convenience of bearing handling and other processes. For the packaging of large bearings, each manufacturer has its own characteristics, such as the material requirements for the outer packaging, anti-counterfeiting marks, and so on.

Compared to other products, the packaging and transportation of bearings are very important. Whether it is a bearing manufacturer or a motor manufacturer, we are inseparable from the transportation link without exception. We must fully communicate with the transportation party and take necessary precautions.

How to maintain the crane slewing ring?

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The slewing bearing is an important “joint” of the crane, so its maintenance is very important. So how to maintain the crane slewing ring?

When carrying out maintenance work, the first thing to pay attention to is the danger of being dragged into the rotating pinion, as well as the danger of crushing and shearing. When performing the following tasks, make sure that when starting the engine to perform the necessary slewing and luffing actions, any maintenance personnel are not in the danger zone between the main boom, the upper car and the reel, or between the exit and the reel. Dangerous areas, except for crane operators (in the driver’s cab).

1. Check the bolts of the slewing ring

1. Before each crane work or at least once a week, visually inspect the bolts on the slewing ring;

2. After the slewing ring has been working for 100 working hours, check whether the bolts are loose or not. Check again at the 300th working hour; check every 500 working hours thereafter; shorten the inspection interval for severe working conditions. If the bolts are found to be loose during the inspection, please stop the construction work and contact the local after-sales service department immediately. The factory or professional technicians will inspect and decide whether to disassemble and inspect immediately.

3. The slewing ring is filled with lithium grease before installation.

4. When replacing bolts, wipe the bolts clean, apply thread fastening glue and tighten them; use a crane in accordance with the requirements of the operation manual and lifting performance table, or check the fastening bolts regularly as required to avoid fatigue damage of the bolts. danger.

2. Routine inspection of slewing ring

1. Regularly check the flexibility of rotation; if noise or impact is found, stop the machine for inspection and troubleshoot immediately, and dismantle and inspect if necessary;

2. Regularly check whether the rotary gear ring is cracked or damaged, and whether the meshing tooth surface has biting, gnawing, peeling, etc.;

3. Regularly check the integrity of the seal. If the seal band is found to be damaged, it should be replaced in time, and if it is found to be off, it should be reset in time.

Three, lubricate the tooth surface of the slewing ring

The slewing ring gear has been coated with anti-rust oil before leaving the factory. The effective period of this anti-rust is generally 3 to 6 months. After the effective period, the anti-rust oil should be coated in time. In addition, during use, prevent the slewing bearing from being directly exposed to sunlight. It is forbidden to rinse the slewing bearing directly with water to prevent water from entering the raceway, and prevent hard foreign objects from approaching or entering the tooth meshing area.

Fourth, the raceway of the sliding slewing ring

The raceway must be filled with grease regularly according to the working environment. After working for 50 working hours, the raceway should be filled with lubricating grease, and then again every 300 working hours. The slewing bearing must be filled with grease before and after being placed for a long time.

If using a steam jet cleaner or a fixed water sprayer to clean the crane, care must be taken to ensure that water does not seep into the slewing ring connection, and then the slewing ring connection must be lubricated. In special working environments, such as tropical, high humidity, dust, large temperature changes, and continuous work, the lubrication cycle should be shortened.

Grease filling should be carried out when the slewing ring rotates slowly. When the lubricating grease overflows from the seal, the filling is completed. The overflowing grease will form a thin film to act as a seal.

Why the slewing bearing is not installed smoothly or even cannot rotate?

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Sometimes the technical indicators were normal when the rotation performance was tested in the factory, but the newly installed slewing bearing and slewing ring showed inflexible rotation. In addition, why the slewing bearing is not installed smoothly or even cannot rotate?

Reasons for the unsmooth installation of the slewing bearing

1, mounting hole. The threaded hole of the mounting hole is not standardized, the thread is not completely, and the thread is defective, which causes the bolt to be unable to be screwed in.

2. The center diameter and chord length of the mounting hole are out of tolerance too much, such as 3-5mm, causing the bolt to fail to perforate.

3, the positioning hole and the step size are out of tolerance and cannot be matched.

4. The bearing after heavy load has a dead center or ellipse in rotation, causing it to fail to operate normally.

5. The bearing is not in the installation direction of the installation design drawing, resulting in the opposite direction of the taper pin, which has potential safety hazards.

6. Interference of installation parts, such as tooth tip interference, there will be teeth gnawing phenomenon, and individual parts conflict with each other.

7. The negative clearance design is unreasonable, resulting in oblique force, unbalanced load and clearance after installation.

8. The equipment structure design is unreasonable, causing the debugging to not be carried out normally.

The slewing bearing may be difficult to rotate or unable to rotate

1. Idling of newly purchased products is not flexible

Please check the production date of the slewing bearing. If it takes a long time (such as more than half a year) and the climate is cold, it is possible that the salt mist and other temperament in the raceway will double the rotation resistance, which will make the slewing ring not work properly (cold areas, more prominent in winter) ) Elimination method: If it can run without other abnormalities, it can be used normally.

2, the operation after installation is not flexible

It may be that the surface of the main machine device and the surface of the slewing ring are not properly matched, resulting in that the axial clearance of the slewing ring behind the device cannot compensate for the deformation of the slewing ring. The slewing ring is in a state of negative clearance, and the rolling elements are difficult to run in the raceway (sometimes with abnormalities). Noise) or poor meshing of the large and small gears; or foreign matter stuck in the large and small gears. Elimination method: re-process the plane of the main machine device to make the device plane meet the requirements; re-adjust the gear meshing backlash according to the requirements, especially pay attention to the gear jump position; check to ensure that there is no foreign matter in the meshing position of the large and small gears; exchange a slewing bearing with a larger gap .

3, the operation is not flexible during use

The sealing strip is damaged, causing foreign matter to enter the raceway (such as poor working conditions, dust immersed in the raceway, etc.), and the isolation block is deformed and difficult to operate; there are hard objects or other conditions at the meshing of the large and small gears, such as broken teeth.

The above is an analysis of the annoying reasons why the slewing bearing is not installed smoothly or even cannot rotate. I hope everyone will be helpful after reading it. When testing the rotation performance of the new bearing, it can rotate lightly, but at this time, it does not represent a reasonable index. The contact point, contact angle, and relative position of the connecting point of the channel are in line, and whether the two circles are close to the perfect circle. The two circles are completely or close to positive balance. In layman’s terms, just like the two rails of a train, they should be close to theoretical parallel, high and low parallel, so that the train will be stable, high-speed, orderly and safe. Therefore, to test the rotation performance, the loading experiment is a very important basis and effective means.