What happens if the slewing bearing is improperly lubricated?

When buying slewing bearings, slewing bearing manufacturers will tell us to lubricate the bearings regularly, but for those who don’t understand, improper lubrication may occur during lubrication. Then, are the consequences of improper lubrication of slewing bearings serious? ? What happens if the slewing bearing is improperly lubricated? What should be paid attention to when lubricating bearings?

Consequences of improper lubrication of slewing bearings

Slewing Bearings

1. Discoloration

Metal-to-metal contact will make the bearing temperature too high, causing the raceways and rollers to become discolored. In mild cases, this discoloration is due to the lubricant contaminating the bearing surface, while in severe cases, the metal discolors due to high temperatures. In all cases, early detection can avoid costly repairs.

2. Bearing heating

When the machine is running, the part where the bearing is installed is allowed to have a certain temperature. When touching the housing of the mechanism with your hand, it should be normal that you don’t feel hot, otherwise it indicates that the bearing temperature is too high. One of the reasons for excessively high bearings is poor lubrication of the bearings. The lubricating oil (or grease) used in rolling bearings has a certain working temperature. When the temperature is too high, water or ash enters the bearing seat, it will be seriously oxidized, emulsified, etc., which will lose its lubrication effect and cause the bearing to suffer from high temperature. And burned. In addition, poor quality of lubricating oil (or grease) itself or failure to add oil (grease) during operation will cause the bearing temperature to rise.

3. Scratches and peeling

Inspect the bearing for signs of cutting into the metal or peeling of the metal. These situations require immediate attention. Scratches and peeling are prone to occur in high-load low-speed applications or continuous high temperatures, and thin or insufficient lubricating oil film will accelerate the occurrence of the problem. Insufficient lubrication, wrong grease selection, or sudden changes in working conditions may cause bearing material to peel off or bearing ribs to scratch.

4. Abnormal bearing noise

If the bearing is in a good state of continuous rotation, it will emit a low whining or buzzing sound. If there is a sharp hiss, squeak and other irregular sounds, it often indicates that the bearing is in a poor continuous rotation condition. The sharp squeaking noise may be caused by improper lubrication.

5. The bearing is completely locked

Extreme local heating will produce metal flow in the bearing, changing the original material and geometry of the bearing. This may result in excessive tilting of the rollers, damage to the cage, and complete lock-up of the bearing. If catastrophic damage does occur, it is recommended to consult a bearing expert to determine the root cause of the problem, because it may be a factor other than lubrication.

Precautions for correct lubrication

Slewing Bearings

1. Choose the right grease

Choosing a suitable grease will make the grease fully play the role of lubrication in the bearing operation, so that the bearing can be used for a longer time. The following are the points that need to be paid attention to when choosing the grease. Let’s take a look.

(1) Look at the working temperature: The working temperature of the lubricating part is an important basis for choosing lubricating grease. The typical components that use grease are rolling bearings. Under high temperature conditions, the temperature of the outer ring of the bearing is 15°C lower than the temperature of the inner ring. The temperature of the bearing operating at medium and low speeds (3000-5000r/min) is similar to the temperature of the internal medium. Under low temperature conditions, synthetic oil grease must be used, especially for some instrument miniature bearings, which have a small aerodynamic torque. Pay special attention to the selection of grease.

(2) Look at the running speed of the bearing: the speed of the lubricating component has a great influence on the bearing life of the grease. Therefore, when selecting lubricating grease, the movement speed of the lubricated part must be considered.

(3) Look at the environment: the environment of the lubricating part and the medium in contact have a great influence on the performance of the grease.

(4) Look at the filling method: the filling method of grease includes manual filling and centralized pump filling. Smearing or filling, grease gun filling, grease cup filling, etc. are manual filling and automatic filling.

2. Choose the right way

(1) Manual lubrication: This is a relatively primitive method. In the case of insufficient lubricating oil in the bearing, use an oiler to supply oil. It is usually used for light-load, low-speed or intermittent motion occasions. It is recommended to use the oil filler hole during operation. Dust cover or ball valve is set on it, and felt, cotton, wool, etc. are used as filter devices.

(2) Automatic lubrication: The automatic lubricator is a device used to replace manual refueling. The main advantage of this device is to save labor. It can refuel regularly and quantitatively, so that the life of the equipment can be prolonged, especially suitable for more complicated working conditions. Bottom, can reduce the safety risk of manual refueling. Using an automatic lubricator, you can continuously lubricate the running equipment automatically.

3. Add grease in time

Choosing the appropriate grease and lubrication method is the prerequisite for lubrication, but it is also necessary to add grease in time in daily use. This is also a problem that people often ignore or forget. Adding grease in time is to ensure that the bearing is running to meet the operating conditions Lubricating oil, which is also the key to extending the service life of the bearing.

The above is the whole content of the consequences caused by improper lubrication of the slewing bearing and the lubrication method. We understand that improper lubrication of the slewing bearing may cause the bearing to change color, heat, scratch and peel, have abnormal noise, lock up, etc. When lubricating, pay attention to the correct selection of grease and timely add grease, etc., which can effectively avoid the occurrence of improper lubrication.

What are the maintenance tasks in the use of slewing bearings? How to maintain?

The slewing bearing is an indispensable part of large-scale machinery. It can be installed in the machine to allow the machine to rotate left and right. At the same time, it can withstand various forces. Because the slewing ring is very important, careful maintenance is required. More than 96% of the slewing ring failures are caused by lubrication problems, pollution, wear and incorrect operation, which seriously affects its service life and normal performance.

1. The slewing bearing is coated with a small amount of grease when it leaves the factory. When the product is used, it should be filled with new grease according to different working conditions.

2. The slewing bearing should be greased regularly. According to different types of slewing bearings, the specific grease filling time is as follows:

a: Ball type: Grease is added once every 100 hours of operation.

b; Roller type: Grease is added every 50 hours of operation.

Slewing Bearings

If in a special working environment, such as: tropical, high temperature, dusty, high temperature and continuous continuous work, the grease filling cycle should be shortened, and the grease should be filled once every 50 hours of work; when the gear is working normally, it should be guaranteed to work every time Apply detergent once every 150 hours. When working vigorously, apply detergent once every 75 hours of work. Note that the teeth must be wiped clean before applying detergent. The machine must be refilled with new grease before and after the long-term stagnation of the machine. Each time the grease is added, the raceway must be filled until it overflows from the sealing device. When the grease is added, the slewing ring must be slowly transferred. Make the grease evenly filled in the raceway.

3. Because there are many comprehensive factors in the process of use, the user can choose the grease according to the specific situation. For example, the raceway can use: No. 3, No. 4 graphite grease, industrial grease, No. 203 grease, No. 7002 High and low temperature bearing grease and No. 2 aluminum-based grease, etc.

Since the slewing ring is installed, after 100 hours of operation, the pre-tightening force of the bolts should be checked, and every 500 hours of operation thereafter, it must be adequate and tried.

4. After the equipment has been working for 2000 hours, if a bolt is found to be loose below 80% of the specified torque, the bolt and two adjacent bolts shall be replaced with new ones; if 20% of the bolts are found to be loose to 80% of the specified torque Below, all bolts are replaced with new ones. After the equipment has been working for 14,000 hours, all bolts should be replaced with new ones.

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5. Pay close attention to the operation of the slewing bearing during use. If you find that the noise, impact, or power suddenly increases, you should stop the machine for inspection immediately until all the faults are eliminated, and disassemble and inspect if necessary.

6. When the slewing bearing is in use, it is forbidden to directly wash the slewing bearing with water to avoid water entering the raceway to cause rust; strictly prevent hard foreign objects from approaching or entering the meshing area to avoid injury to the teeth or unnecessary trouble.

7. To keep the surface of the slewing bearing clean, choose a suitable solvent for cleaning according to the surface properties of the rust-proof object, so as to avoid serious corrosion. Surface cleaning can use chemical treatment cleaning method and mechanical cleaning method. When the surface is dry, do a good job in controlling the temperature and wait until most of the area is dry before wiping it with gauze. When applying anti-rust oil, it is necessary to apply different methods according to the different properties of the bearing surface. Miniature bearings can be directly immersed in anti-rust grease. If you encounter a special shape, you can choose the painting method, so that it is not easy to produce accumulation. There are many factors that cause metal corrosion. The chemical composition of the metal itself can also cause corrosion or the temperature and humidity of the environment in which the item exists can also cause corrosion.

8. The sundries on the surface of the slewing ring should be removed frequently during use, and the sealing strips of the slewing ring should be checked for aging, cracking, damage or detachment. If one of these conditions occurs, the sealing strips should be replaced in time to prevent debris and debris from entering the raceway. If the grease is lost, the corresponding grease should be applied after replacement to avoid jamming or rusting of rolling elements and raceways.

The above is a detailed explanation of the maintenance work in the use of the slewing ring. In short, the slewing ring has malfunctions such as noise and impact after a period of use. The operator should pay attention to observe and check in time to eliminate the fault. Only correct and reasonable maintenance of the slewing bearing can ensure its normal operation, give full play to its performance, and extend its service life.

Scrap Standard and Service Life of Tower Crane Slewing Bearing

All machines will suffer loss and failure after a long period of use. When the parts exceed the service life or are damaged beyond repair, they should be scrapped and replaced. The tower crane slewing bearing is prone to failure and damage when subjected to harsh outdoor environments and high-load operation for a long time. So to what extent can it meet the scrap standard of the tower crane slewing bearing?

The scrap standard of tower crane slewing bearing

Slewing Bearings

1. The slewing ring and rolling elements are worn out and scrapped

The wear of raceway ring and rolling element is one of the common forms of slewing bearing scrap. When the raceway pitting corrosion occurs on the surface of the slewing bearing, the surface metal is peeled off and the overall wear is worn, the tower crane will experience abnormal noise, rolling element jamming and excessive clearance between the raceway rings during operation; vibration and local impact will be caused. With the development of the state, the turning resistance will continue to increase and the turning function will be lost.

2. The slewing ring cage is damaged and scrapped

In order to avoid friction between the rolling elements of the tower crane slewing support, an isolator cage is usually added between the rolling elements. The material of the cage is generally copper, plastic, powder metallurgy or mild steel. The cage does not transmit load during the bearing, but it moves with the rolling elements. When the cage is damaged or broken, there will be a sharp and piercing noise. As the broken body of the cage is pushed and crushed by the rotating rolling elements, it will cause serious damage to the raceway ring and rolling elements. At this time, the slewing bearing meets the scrap standard and can be replaced.

3. The slewing ring teeth are damaged and scrapped

The gear meshing mode of the tower crane slewing support has two kinds of external gear meshing and internal gear meshing. When the surface of the gear teeth is excessively worn, cracks and broken teeth appear. The tooth side clearance of the gear teeth of the tower crane slewing bearing is enlarged, and the slewing bearing will immediately lose its function when the tooth is broken and cannot be repaired. At this time, it reaches the scrap standard of the tower crane slewing bearing.

4. The slewing ring connecting bolts are damaged and scrapped

Although the connecting bolt of the slewing ring is not the bearing body, the failure of the bolt will also cause the slewing ring to fail to work. The damage of connecting bolts in tower crane work is also a common phenomenon. When a slewing bearing connecting bolt is loosened or broken, it will often cause a chain reaction to cause the loosening and fracture of other bolts. At this time, the slewing bearing also needs to be replaced.

5. The slewing bearing is damaged and scrapped due to corrosion and burns

Due to the complex working environment of the tower crane slewing bearing, the situation that the bearing may encounter is also unpredictable. If it is corroded by corrosive substances such as acid and alkali during operation, the internal components of the bearing will be damaged and the bearing will be scrapped.

The service life of the tower crane slewing bearing

Slewing Bearings

Under a certain load, the number of revolutions or hours that the bearing experiences before pitting corrosion is called the bearing life. The service life of the tower crane slewing bearing is affected by the speed, radial load, basic rated load, equivalent conformity, speed coefficient, and fatigue life coefficient.

1. Calculation formula of bearing life

L10-When the bearing load is P, the basic rating life (106 revolutions)

C–Basic dynamic load rating N

ε–index

Ball bearing: ε=3

Roller bearing: ε=10/3

P–Equivalent dynamic load (N)

The load on the bearing under actual conditions: A, R, transformed into the load under experimental conditions is called equivalent dynamic load. For bearing components, this load is variable. In the experimental study, the bearing life is changed to 106 The unit is more convenient (counter), but in actual production, the life is generally expressed in hours. For this reason, it must be converted L10×106=Lh×60n

2. Calculation method of tower crane slewing bearing life

(1) Knowing the bearing model, load and shaft speed, calculate Lh;

(2) Knowing the load, speed and expected life, calculate C and select the bearing model.
Usually take the middle repair or overhaul limit of the machine as the design life of the bearing, generally Lh’=5000, and the temperature coefficient ft should be introduced for the bearing working at high temperature

Ct=ftC

t ≤120 125 150 200 300

ft 1 0.95 0.90 0.80 0.60

The above is about the relevant content of the scrap standard of the tower crane slewing bearing. The tower crane’s service life may be affected due to its complicated use environment. At the same time, good maintenance and repair can also extend the service life of the tower crane slewing bearing.

What are the reasons for the deformation of the slewing bearing?

Slewing bearings are widely used on rotating machines such as ferris wheels and excavators, and the wide range of applications also reflects that the work load of slewing bearings is relatively high, and high-load work makes slewing bearings in use. Many problems will be encountered, and bearing deformation is one of the more common problems. So, what are the reasons for the deformation of the slewing bearing? How can we control the deformation of the slewing bearing? The slewing bearing manufacturer will introduce the related problems of the deformation of the slewing bearing, and I hope it will be helpful to everyone.

Causes of deformation of slewing bearings

Slewing Bearings

1. Irregular installation

In fact, there are still more attentions in the installation process of slewing bearings. For example, in the process of bearing installation, it is necessary to accurately calculate the interference of the rotating ferrule and the appropriate fit of the fixed ferrule. Especially slewing bearings work on machines like excavators, ferris wheels, etc., and the temperature rises easily during the working process. At this time, special attention should be paid to the matching of the rotating ring not to be too loose to prevent eccentric vibration, and There must be no gap in the fit of the fixed ferrule to prevent the ferrule from deforming under load and excite vibration, which will affect the service life of the bearing.

2. Bearing wear

Wear is almost accompanied by the entire life cycle of the machine, but this natural wear has a certain degree of stability. However, if the amount of lubricating oil is too low or missing, it will cause rapid wear of the bearing, and the damage to the bearing by this unnatural wear will be irreversible. Only by overhauling the machining accuracy and straightness of the bearing can it be completely repaired.

3. Friction heat generation

During the working process of the slewing bearing, the temperature rises due to the load of the workpiece and the friction between the bearing rolling elements and the inner and outer rings, which causes the bearing to deform due to heat expansion. If the amount of lubricating oil is sufficient and effective, this kind of thermal deformation can be effectively curbed. I am afraid of the dry grinding caused by the lack of lubricating oil in the second case mentioned above. In this state, not only will the bearing raceway wear and out of stock, but also a large amount of frictional heat will be generated, which will cause bearing damage and premature failure.

Methods to prevent deformation of slewing bearings

Slewing Bearings

1. Reasonable installation

(1) Keep hands clean and dry when taking out: When the turntable bearing is taken out of the package, the operator’s hands should be kept clean and dry, because sweat on the hands can cause rust, and gloves can be worn if necessary. However, it is necessary to pay attention to gloves. It is recommended to use cotton gloves to avoid scratching the bearings due to the rough surface of the gloves.

(2) Reasonable use of force: during bearing installation, the installation force should not be transmitted through the bearing rolling elements, and attention should be paid to the control of the force during installation, to avoid direct application of force to the bearing, and to minimize the effect of force on the bearing. Injury caused by the bearing.

2. Lubricate correctly

(1) Lubricant selection: When choosing the right grease for rolling bearings, you usually need to consider the following factors: bearing type, speed, working temperature and load, as well as installation position, sealing, shock and vibration, and consideration The requirements of laws and regulations and environmental protection, only to meet these requirements is a more suitable grease.

(2) Grease adding method: common slewing bearing grease adding methods include oil mist lubrication, oil-air lubrication, grease lubrication, jet lubrication, etc. Among them, grease lubrication does not require any equipment and is a relatively common lubrication method. The lubrication method is simple and easy to operate. Other methods have their own advantages. You can consider them according to the situation.

3. Ensure that the slewing bearing is clean

(1) Bearing cleaning: When cleaning, you should first pinch the inner ring of the bearing with one hand, and slowly rotate the outer ring with the other hand, until the oil on the rolling elements, raceways and cage of the bearing is completely washed off, then clean the bearing. The surface of the outer ring. At the beginning of cleaning, it should be rotated slowly, swayed back and forth, and rotated too hard, otherwise the raceways and rolling elements of the bearing will be easily attached to dirt.

(2) Isolation of impurities and dust: Bearings are easy to hide dirt and dirt. After all, the working environment of bearings is more complicated. Therefore, after the bearing cleaning work is completed, it is recommended that you use a layer of grease to seal it. This can reduce bearing contamination.

The above is a summary of the reasons for the deformation of the slewing bearing, the reasons and prevention methods. It can be seen that the reasons for the deformation of the slewing bearing include irregular installation, bearing wear, friction and heat generation, etc., and the corresponding prevention Measures include reasonable installation, effective lubrication, and keeping clean.

How long is the service life of the slewing bearing? What are the factors that affect the service life?

How long is the service life of slewing bearings in general? There are many factors affecting the service life of a bearing. Different working conditions, different materials, and different bearing types will affect the service life of the bearing. For this reason, the service life is not a standardized number but is based on the material, process, and production level during production. As well as the use method, maintenance lubrication conditions and other factors in the process of use, it is comprehensively determined. Let’s take a look at the factors that determine the service life of the bearing and the method of extending the service life with the slewing bearing manufacturer.

How long is the service life of the slewing bearing?

According to the influence of the bearing material, assembly, tolerance fit, lubrication and other factors, the service life of the slewing bearing under normal conditions ranges from 10,000 to 192,000 hours. We generally say that the service life of bearings is different on different types of bearings. Like ordinary bearings, the service life of the bearing refers to the failure of use, such as pitting, spalling and other conditions that cannot work normally. For spindle bearings and precision bearings that require high precision, they will fail when the running accuracy of the bearing fails to meet the requirements, but it is far below the standard for ordinary bearing failure. So this is also the reason why the service life of the slewing bearing is different.

Factors affecting the service life of slewing bearings

Slewing Bearings

1. Manufacturing factors

(1) Design: Whether the diameter, quantity, ring wall thickness, effective length of rolling contact, tightness, radian and size of the raceway contact surface of the bearing rolling elements are compatible with the adapted equipment.

(2) Material: Martensite in the quenched steel during the bearing production process, impurities in the steel, chemical composition, gas, cracks, etc. The impact of the material on the quality of the bearing is hard damage, which cannot be compensated by technology in the later stage.

(3) Manufacturing: In the process of producing slewing bearings, bearing parts hardness, bearing metallographic structure, surface burns, bump scratches, roughness, poor parts grouping, production accuracy, bearing clearance, cleanliness, residual magnetism and parts Residual stress on the working surface will affect the service life of the bearing. The impact during the manufacturing process is similar to the inherent quality problem. Under the same working conditions, a defective bearing has a shorter life than a standard and qualified bearing.

Slewing Bearings

2. Use factors

(1) Model selection: In terms of model selection, such as bearing load, hardness, operating environment, etc., a good bearing design will first enable the bearing to reach the upper limit of the theoretical life.

(2) Assembly: the installation accuracy of the bearing, the matching degree of the bearing shaft and the seat hole, the selection of various parts, dimensions, shape and position accuracy, the selection of assembly tools, and the cleanliness of installation whether there are impurities mixed in, including the assembly position and assembly of each part Clearance, preload size, lubricant selection and filling amount, etc.

(3) Working environment: The working temperature and the cleanliness of the working environment affect the service life of the bearing. If the operating environment of the bearing is in a harsh environment or a high temperature, high temperature, low temperature and severe cold environment, it may affect the performance of the bearing. The service life has a certain impact.

(4) Load: Each bearing has a rated load when it is produced. There is a range for the load borne during the bearing operation, that is, the force condition. If it exceeds this range for long-term overload operation, the performance of the bearing may be seriously affected. The impact of this, which in turn affects the service life.

(5) Lubrication: Bearing lubrication is a key factor in reducing the friction between the various parts of the bearing and reducing the occurrence of damage and deformation. Therefore, whether the bearing lubrication is appropriate, timely and reasonable has a certain impact on the service life of the bearing.

The above is the relevant answer about how long the service life of the slewing bearing is generally. In fact, if you want to extend the service life of the bearing, you only need to correctly select and assemble, maintain a good working environment, and use it correctly to maintain and supplement the lubricant. The service life of the bearing can be increased.

What are the oil lubrication methods for slewing bearings?

The slewing bearing needs to be lubricated during use and storage. The common lubrication methods are grease lubrication and oil lubrication. The medium for grease lubrication is grease, and the oil lubrication is lubricating oil. Then, for the turntable In terms of bearings, what are the benefits of using oil lubrication? What are the oil lubrication methods for slewing bearings? The following is a summary made by the editor for everyone, let’s take a look.

The benefits of oil lubrication for slewing bearings

The slewing bearing is lubricated by oil lubrication, which can achieve good cooling and cooling effects. This oil lubrication method is very suitable for bearings with relatively high operating temperatures. The viscosity of the lubricating oil used in the bearing is about 0.12 to 0.2cm/s. If the bearing load is high and the working temperature is high, choose a high-viscosity lubricating oil, and a rolling bearing with a fast speed is suitable for a low-viscosity lubricating oil. But it should also be noted that oil lubrication requires that the bearing must be kept in a good sealing state to avoid leakage of lubricating oil. In addition, oil lubrication requires a more complicated oil supply device, so you must pay more attention to the operation and use, and pay attention to the use and maintenance of the bearing.

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The method of lubricating slewing bearing oil

1. Oil bath lubrication

Oil bath lubrication is a relatively common lubrication method. It is suitable for the lubrication of low and medium speed bearings. Imported bearings are partially immersed in the groove, and the lubricating oil is picked up by the rotating bearing parts and then flows back to the oil groove. The oil level should be slightly lower than The center of the lower rolling element.

2. Dripping oil lubrication

Drip lubrication is suitable for imported bearing parts that require a quantitative supply of lubricating oil. The amount of dripping oil is generally one drop every 3-8 seconds. Excessive oil volume will cause the bearing temperature to increase.

3. Circulating oil lubrication

Use an oil pump to deliver the filtered oil to the bearing components, and then filter and cool the lubricating oil after passing through the bearing for use. Because circulating oil can take away a certain amount of heat and cool the bearing, this method is suitable for bearing parts with higher speeds.

4. Spray lubrication

Dry compressed air is mixed with lubricating oil through a sprayer to form oil mist. Injecting into the bearing, the airflow can effectively cool the bearing and prevent the intrusion of impurities. This method is suitable for the lubrication of high-speed and high-temperature bearing components.

5. Jet lubrication

Use an oil pump to inject high-pressure oil into the bearing through a nozzle, and the oil injected into the bearing flows into the oil groove through the other end of the bearing. Imported bearings have higher rated load, lower noise, greatly reduce warranty costs, increase machine running time and other advantages; when distinguishing the authenticity of such imported bearings, you can touch the steel stamp on the bearing to make it faster and more efficient. Accurately distinguishing, this kind of steel seal will not feel tactile if you touch it with your hand, but you can feel the presence of the steel seal by gently touching it with your fingernail. When the bearing rotates at a high speed, the rolling elements and the cage also make the surrounding air form an airflow at a relatively high rotation speed. It is difficult to send the lubricating oil to the bearing by the general lubrication method. At this time, the lubricating oil must be sprayed by high-pressure injection. In the bearing, the position of the nozzle should be placed between the inner ring and the center of the cage.

The above is the slewing bearing manufacturer’s summary of the oil lubrication methods for slewing bearings, the benefits of slewing bearing oil lubrication and all the common methods. We understand that oil lubrication can help the bearing achieve a good cooling and cooling effect. The oil lubrication methods include oil bath lubrication, drip lubrication, circulating oil lubrication, spray lubrication, jet lubrication, etc. You can choose according to your own reagent needs

How often is the slewing bearing maintained and how to maintain it?

After the slewing bearing is used for a period of time, it is inevitable that there will be problems such as noise, vibration, and temperature rise. In this case, if you want to extend the service life of the bearing, you need to maintain the slewing bearing regularly. Then, how long is the slewing bearing? Maintenance once? What is the maintenance method? What problems should be paid attention to during maintenance? Next, the slewing bearing manufacturer will introduce the maintenance cycle and method of the slewing bearing to everyone, and I hope it will be helpful to everyone.

Slewing bearing maintenance cycle

How often is the slewing ring bearing maintained? The maintenance time of slewing bearings is the same as that of ordinary bearings. Theoretically, they can be used for 20000-80000 hours, but the specific life depends on the wear during use, work intensity and later maintenance, etc., among which maintenance is an important part of prolonging the service life of the bearing. ring.

Maintenance method of slewing bearing

Slewing Bearings

1. Clean the slewing bearing

Cleanliness has a considerable impact on the life of the slewing bearing. The higher the cleanliness of the bearing, the longer the life. Lubricants with different cleanliness have no effect on the life of the bearing. Therefore, improving the cleanliness of the lubricating oil can prolong the life of the bearing. In addition, if the dirt particles in the lubricating oil are controlled below 10um, the life of the bearing will also increase several times. So, how should the specific bearing cleaning be done? We then look down.

(1) The cleaning of the bearing is divided into rough cleaning and fine cleaning, and a metal grid can be placed on the bottom of the container in use.

(2) For rough washing, use a brush to remove grease or adhesions in oil. At this time, if the bearing is rotated in oil, be careful that the rolling surface may be damaged by foreign matter.

(3) During the fine washing, slowly rotate the bearing in oil, which must be carried out carefully. Commonly used cleaning agents are neutral non-water-containing diesel or kerosene, and sometimes warm lye etc. are used as needed. No matter what kind of cleaning agent is used, it must be filtered frequently to keep it clean. After cleaning, immediately apply anti-rust oil or anti-rust grease on the bearing.

2. Derusting bearings

(1) Soaking method: Some small items are immersed in anti-rust grease, and the cross tapered roller bearing is coated with a layer of anti-rust grease on the surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease.

(2) Brushing method: used for outdoor construction equipment or products with special shapes that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to accumulate, but also to prevent leakage.

(3) Spray method: Some large anti-rust objects cannot be oiled by immersion method. Bearings are generally sprayed in clean air with filtered compressed air with a pressure of about 0.7Mpa. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted.

3. Bearing lubrication

(1) Manual lubrication: This is a relatively primitive method. When the lubricating oil of the bearing is insufficient, use an oiler to supply oil. However, this method is difficult to maintain a certain amount of oil. It is more dangerous to forget to refuel due to negligence. It is usually only used in light-load, low-speed or intermittent sports. It is recommended to install a dust cap or ball valve on the refueling hole and use it. Felt, cotton, wool, etc. are used as filter devices.

(2) Dropping point lubrication: usually used for light-load and medium-load bearings with a peripheral speed of less than 4~5m/s. A roughly fixed amount of lubricating oil is supplied from the container through holes, needles, valves, etc., the more classic is dripping oil Cup, the amount of dripping oil varies significantly with the viscosity of the lubricating oil, the bearing clearance and the position of the oil supply hole.

(3) Oil ring lubrication: The lubricating oil from the oil pool is brought to the bearing by the ring that is hung on the shaft and can rotate (only for the lubrication method of the horizontal shaft), suitable for medium and high speed shaft diameters greater than 50mm Bearings and oil rings are recommended to be seamless. When the bearing width-to-diameter ratio is less than 2, only one oil ring can be used, otherwise two oil rings are required.

(4) Oil rope lubrication: Relying on the capillary and siphon action of the oil rope to guide the lubricating oil in the oil cup to the bearing, it is mainly used for light-load and medium-load bearings with a peripheral speed of less than 4~5m/s. Can play a filtering role in the whole process.

(5) Oil pad lubrication: Use the capillary action of the oil pad to apply the lubricating oil in the oil pool to the surface of the shaft diameter. This method can keep the friction surface clean, but dust will also block the pores and cause insufficient oil supply. The oil supply of oil pad lubrication is usually only 1/20 of oil lubrication.

Precautions for maintenance of slewing bearings

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1. Precautions for cleaning

(1) Qualified new bearings are not cleaned: New bearings that have passed inspections may not be cleaned under normal operating conditions (motors with more than 2 poles); new sealed bearings are not cleaned.

(2) Clean before oil change: The bearing cap and bearing must be cleaned before oil change. The cleaning is divided into rough washing and fine washing. The oil for rough washing is clean diesel or kerosene, and the oil for fine washing is clean gasoline.

(3) Inspection during cleaning: After the bearing is cleaned, turn it by hand and shake it radially and axially by hand to determine whether it is loose or the gap is too large. Check the gap if necessary. If the ball or roller frame is found to be severely worn, rusted, and metal peeling, it should be replaced.

(4) Wipe dry and grease after cleaning: After the bearing is cleaned and inspected, wipe the cleaning agent (or dry) with a white cloth, and add qualified grease. It is not allowed to add different types of grease in the same bearing.

2. Precautions for rust removal

(1) Selection of derusting liquid: Note that the following acid liquids cannot be used for bearing derusting: sulfuric acid, hydrochloric acid, dilute sulfuric acid, and dilute hydrochloric acid. Because these acid liquids will destroy the good metal parts, these kinds of liquids cannot be used!

(2) Selection of rust removal methods: I have introduced several common rust removal methods above, including soaking method, brushing method, spraying method, etc. You can choose according to the actual situation of the bearing, but no matter which method it is It is necessary to pay attention to the protection of the bearing during operation. The damage to the bearing due to maintenance is more than the loss.

3. Precautions for lubrication

(1) No dust in the surrounding environment when refueling: refuel with clean hands, slowly rotate the entire bearing with one hand, and press the oil into the bearing gap with the middle finger and index finger of the other hand. After adding one side, proceed to the other side to remove excess grease.

(2) Bearing and bearing cap refueling volume: The bearing cap oil volume is 1/2-2/3 of the bearing cap capacity (the highest number of poles of the motor is the upper limit); the bearing oil volume is 1/2-2/3 of the cavity of the inner and outer rings of the bearing ( The number of motor poles is higher than the upper limit).

The above is about how often the slewing bearing is maintained, the maintenance cycle and the entire content of the method. We understand that the general slewing bearing is maintained every 20000-80000 hours. The specific time needs to be determined according to the actual situation. The maintenance method includes regular cleaning, which is effective. Rust, reasonable lubrication, etc. It can be seen that if you want to extend the service life of the slewing bearing, you still need to work harder and maintain it.

What is the manufacturing process of slewing bearings

Slewing ring bearings are also called slewing bearings. The main structure includes: inner ring, outer ring, rolling elements, and rolling element-guided cages. They are important transmission components in mechanical equipment. They are used in engineering machinery, light industrial machinery, metallurgical machinery, medical machinery, Ship equipment and other industries are widely used. Next, the slewing ring manufacturer will take you to understand the manufacturing process and detailed steps of the slewing ring.

1. Cutting of slewing bearing steel material

The commonly used raw material for slewing bearings is integrally hardened carbon-chromium bearing steel, and the slewing ring is made of surface hardened steel, generally made of 50Mn steel, such as: S48C, 42CrMo, 5CrMnMo. The cylindrical raw material billet transported back from the steel mill is cut according to the size required for processing the bearing. Generally, carbide saw blades should be used for cutting bearing steel, which have high hardness, wear resistance, strength and toughness, heat resistance, corrosion resistance, etc. A series of excellent properties.

2. Slewing bearing billet forging

In the heating furnace, the billet is heated and forged into a round cake shape. The forging link is an important link to ensure the reliability and life of the bearing. After the raw material is forged, the bearing ring blank is formed. At the same time, the organization structure of the raw materials becomes denser and the flow linearity becomes better, which can improve the reliability and service life of the bearing. In addition, the quality of the forging process will directly affect the utilization rate of raw materials, thereby affecting production costs.

Slewing Bearings

3. Slewing ring forged ring

The steel blank is forged into a ring-shaped steel ring using a ring rolling machine. Forging can improve the internal structure of steel and improve the strength, plasticity, impact toughness and other mechanical properties of steel.

4. Rough turning processing

The steel ring after the ring is put into the machine tool, and the rough turning of machining is performed, and various groove raceways are turned out, and the steel ring is fixed on the gear milling machine to cut teeth. The main purpose is to make the shape of the ferrule after the final product the same, creating conditions for the later grinding machine processing.

5. Slewing bearing quenching (heat treatment)

After machining, through quenching operation, the strength and hardness of the steel are improved, and the wear resistance, fatigue strength and toughness of the metal are improved. The heat treatment process is to subject the forged and machined bearing ring to high temperature treatment, which directly affects the uniformity of carburization in the bearing ring, improves the wear resistance and hardness of the bearing, and also affects the reliability and life of the bearing. Important link.

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6. Hole processing of slewing bearing

Drill the mounting hole on the end face of the steel ring. When opening the slewing bearing bearing, determine the center and cutting angle. Choose a drilling machine, hand-held electric drill and hand drill for operation.

7. Fine grinding

Finishing is to trim the fine parts of the bearing roughly formed after the hole is opened to ensure the refinement of the appearance. Finishing has an effect on the rotation flexibility of the bearing and the precision of the bearing surface. Once again, the raceway surface of the steel ring is finished. Modify the deformation caused by the previous process.

8. Slewing bearing assembly operations

Assemble the parts (outer ring, inner ring, roller, cage) processed through various processes, such as inserting steel balls, spacer blocks, and inserting butter sealing strips. Assemble a set of finished bearings according to different technical and precision requirements.

9. Slewing bearing finished packaging

The finished bearing will be coated with anti-rust oil, packaged and packaged. At the same time, it will be sampled and inspected by the factory inspector, and the qualified products will be issued with a certificate, and then sold.

The above is the related content of the slewing bearing manufacturing process and production operation specifications introduced by the slewing bearing manufacturer, including the selection of slewing bearing material cutting, forging, turning processing, heat treatment, grinding processing, assembly and other related content for your reference.

What material is good for the slewing bearing and how should it be selected?

The material of the slewing bearing directly determines the performance and service life of the bearing. At present, the main structure of bearings on the market is mostly made of bearing steel, which has the characteristics of corrosion resistance and stability. Of course, in addition to bearing steel, there are also metal materials such as aluminum alloy or copper. In addition, the sealing ring and cage of the bearing may be different from the material of the main body of the bearing. The following slewing bearing manufacturers will share what material is good for the slewing bearing.

What material is good for the slewing bearing?

Slewing Bearings

1. Material of ferrule and rolling element

The early slewing bearing used 45# steel, but it was gradually eliminated due to poor modulation performance in the later period. In the current more common processing technology, the slewing bearing rolling element adopts integrally hardened carbon chromium bearing steel. The grade is made of GCr15 or GCr15SiMn steel; the ring of the slewing bearing is made of surface hardened steel, and if there is no special requirement, it is made of 50Mn steel. But sometimes customers also choose to customize other grades such as 42CrMo, 40Cr, etc. The following describes the characteristics of these grades of steel.

(1) As a high-carbon steel, 42CrMo has good quenching and quenching properties and is an ideal material for slewing bearings.

(2) 50Mn has good hardenability and is also a high-quality choice for slewing bearings.

(3) 40Cr is also good in terms of mechanical properties, and it is still in the exploration and practice stage.

(4) GCr15 small slewing bearing can be selected, but it is generally not recommended to use it because of the troubles caused by full quenching in the process of milling and drilling.

2. Material of cage

Cages for slewing bearings have structural forms such as integral, segmented, and isolated block types. The types of cage materials are: low carbon steel stainless steel cage, bakelite/plastic (nylon) cage, brass/bronze/aluminum alloy cage, etc. The spacer type is made of polyamide 1010 resin, ZL102 cast aluminum alloy, etc. .

The characteristics of various material bearing cages are as follows:

(1) Steel bearing cage: It is often cold stamped from 08 and 10 carbon steel sheets. Commonly used steel cage materials include 20, 30, 45, 0Cr18Ni9, 1Cr18Ni9Ti, 40CrNiMo, ML15, ML20, etc., which are commonly used materials in bearing cages, which are solid, durable and stable.

(2) Non-ferrous metal bearing cage: Different from steel, non-ferrous metal has its special properties. For example, aluminum alloy has the characteristics of low density, good thermal conductivity, and good corrosion resistance; copper alloy has good thermal conductivity, low friction coefficient, Features such as good formability and high use temperature; zinc-aluminum alloy has the advantages of low cost, low density, and excellent performance.

(3) Non-metallic cage: non-metallic cage materials mainly include polymers and their composite materials, including nylon, phenolic tape, polytetrafluoroethylene, etc. The polymer material has good strength and elasticity matching, which can effectively reduce the heating and wear of the bearing.

3. Material of sealing ring

Bearing sealing materials are generally commonly used sealing materials, mainly: nitrile rubber, silicone rubber, fluorine rubber, EPDM, fluorobutadiene rubber, polytetrafluoroethylene, polyurethane rubber, acrylic rubber, Anaerobic glue, etc.

The sealing ring of the slewing bearing is made of oil-resistant rubber or NBR nitrile rubber. Compared with nitrile rubber, hydrogenated nitrile rubber has better oil resistance, but if you are not too demanding on oil resistance, use nitrile rubber, because hydrogenated nitrile rubber is relatively expensive. Nitrile rubber also has a certain degree of acid and alkali resistance. However, silica gel should be selected if the requirements for oil resistance and acid and alkali are higher, but its price is higher.

How to choose the material of the slewing bearing

Slewing Bearings

The slewing bearing manufacturer said that the materials used in slewing bearings should be analyzed based on the current level of slewing bearing production technology. It is recommended that the materials of bearing rings, rolling elements, cages, and sealing rings should first consider the following materials.

1. Material of rolling element: GCr15SiMn is generally used for rolling element.

2. Ring material: 50Mn is used for the slewing bearing ring, but sometimes 42CrMo is used to meet the needs of the host in special applications.

3. Cage material: The cage has different structure types such as integral type, segmented type and isolated block type. The integral or segmented retainer adopts 20# steel or ZL102 cast aluminum alloy. The isolating block holder adopts polyamide 1010 resin, ZL102 cast aluminum alloy or QA110-3-1.

4. Sealing ring material: The slewing bearing should be made of oil-resistant rubber, fluorine-containing rubber, and oil-resistant nitrile rubber. The clearance of the slewing bearing The clearance of the slewing bearing is mainly used to compensate the manufacturing error and installation error of the slewing bearing supporting parts and the relevant host assembly parts to ensure the normal use of the bearing. According to the structure type/tolerance class of the slewing bearing and the pitch circle diameter of the rolling element group, the clearance value or the interference amount of the slewing bearing.

The above is the introduction of the slewing bearing manufacturer on the material of the slewing bearing. The bearing materials mentioned are all suitable for slewing bearings, but the specific use environment and performance requirements may have different requirements for the bearing materials. Please follow the actual situation. Choose the situation.

Slewing bearing maintenance methods and maintenance precautions

There are many types of bearings, and the fields and equipment used by each type of bearing will be different. Among them, the slewing bearing can be rotated and used in many equipment and machines. It can be said to be the scope of use. There is a very wide range of bearings, so what are the maintenance methods of the slewing ring and what are the precautions in the maintenance process? The slewing ring manufacturer gave us the following detailed introduction.

Maintenance method of slewing bearing

1. After 100 hours of operation of the slewing ring, the pre-tightening force of the bolts should be checked, and every 500 hours of operation thereafter, sufficient pre-tightening force must be maintained.

2. When the slewing ring is in use, if noise, impact, or power suddenly increases, it should be shut down immediately for inspection, troubleshooting, and disassembly and inspection if necessary.

3. The raceways of the slewing bearing are regularly filled with grease. Generally, the ball bearings are refueled every 100 hours of operation, and the roller bearings are refueled every 50 hours.

4. The tooth surface of the slewing bearing should be cleaned of debris frequently and coated with corresponding grease.

5. The slewing bearing and slewing ring tooth surface should be cleaned up for 10 shifts, and grease should be reapplied.

Matters needing attention in maintenance of slewing bearing

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1. The mounting support of the slewing ring must have sufficient rigidity and the mounting surface should be flat. The support should be subjected to stress relief before assembling the slewing ring. The slewing bearing and slewing ring should be repaired and maintained to reduce the deformation of the slewing ring support. The support should be assembled during assembly. The contact surface with the slewing bearing must be cleaned.

2. When using slewing bearings and slewing bearings, attention should be paid to changes in noise and slewing resistance torque. If there is any abnormality in the maintenance of slewing bearings and slewing bearings, they should be disassembled for inspection. The slewing bearings must be hoisted or stored horizontally, not vertically. Lift or store to avoid deformation.

3. Before the bolts are tightened, the slewing bearing and slewing support should be checked for gear meshing. The meshing condition should meet the requirements of gear accuracy, that is, the contact spots distributed on the tooth surface after the gear pair runs under slight braking. The tooth height direction is not less than 25%, and the tooth length direction is not less than 30%.

4. Slewing bearing and slewing ring In order to ensure the reliability of bolt work and avoid the lack of bolt pre-tightening force, the slewing bearing and slewing ring should be checked for the pre-tightening torque of the bolts after 100 hours and 500 hours of operation of the slewing ring. The pre-tightening torque should be checked every 1000 hours of work.

The service life of the slewing ring during work is directly proportional to the maintenance performed on it. Good maintenance of the slewing ring is also a way to avoid the failure of the slewing ring. The maintenance methods of the slewing ring above are only part of it. Friends who want to know can check our company website. The slewing ring produced by LDB Bearing Co., Ltd. is of good quality, which can effectively improve labor productivity and equipment stability. You are welcome to call our hotline or leave a message at the bottom of the website.