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4 point contact ball slewing bearing

1.Analysis of common faults of 4 point contact ball slewing bearing and preventive improvement measures

The damage of the slewing bearing is much more complicated than that of the general mechanical parts.

It is damaged in various forms and for different reasons. In addition to the own factors of bearing design and manufacture, most of the damages are caused by improper bearing selection, unreasonable design of support seat frame, weak rigidity and poor flatness of connecting surface, overload operation, improper installation, poor lubrication and poor sealing.

Strict and other factors related to use. Studying the damage form of the slewing bearing and analyzing the cause of the failure, on the one hand, can provide detailed information for the correct design and selection of the bearing, and then improve the design, select the bearing reasonably, give full play to the function of the bearing, and improve the economic benefit.

On the other hand, it is more important to improve the safety of use and avoid major accidents.

1. Failure caused by improper bearing selection

Correct and reasonable selection of slewing bearings is the guarantee to give full play to the function of bearings. If the mechanical design is not fully considered, overloading of the load can occur, resulting in the chipping of the rolling elements, the peeling of the raceways or the appearance of cracks.

Satisfying the bearing capacity is the primary consideration, the internal parameter design is the key factor, and the reasonable selection of materials and the heat treatment state of the materials is also important.

According to the actual working conditions of the main engine, the spatial position, the size and nature of the load, the rotational speed, the rotational accuracy, the friction torque and the installation method should generally be considered. In addition, the clearance of the 4 point contact ball slewing bearing is also a factor that cannot be ignored.

Generally speaking, for applications such as construction machinery, mining machinery and hoisting machinery, the bearing should usually choose a larger clearance.

If the clearance is too small, after the bearing is fixed, due to the poor flatness of the bearing, the bearing clearance will be reduced, which will cause the bearing to be stuck during operation or the rolling elements will squeeze each other. too high to cause failure.

On the other hand, due to the influence of the flatness of the bearing surface, the fixed bearing appears “wave-shaped”, so that the rolling elements are not on the same plane, resulting in excessive friction torque.

According to experience, in general, the clearance of the slewing bearing should not be less than 1.2 times the flatness of the mounting surface

2. Failure caused by insufficient rigidity of the supporting seat frame

The rigidity of the 4 point contact ball slewing bearing itself is not good. If the rigidity of the seat frame is insufficient, the slewing bearing will be deformed with the deformation of the seat frame, resulting in the unevenness of the original clearance, resulting in the uneven running of the bearing during operation and abnormal noise.

This situation has a particularly obvious impact on crossed cylindrical roller bearings, resulting in no clearance in many parts of the bearing, and wear between rollers and rollers, raceways and rollers due to mutual extrusion.

At the same time, the deformation of the seat frame will not only cause the raceway to separate and warp, affect the meshing clearance and meshing performance of the ring gear and the pinion, and then affect the working quality of the main engine, but also cause edge stress on the raceway and the rolling elements, causing the bearing Early failure.

The slewing bearing is fixed with the main engine by bolts, and the deformation caused by insufficient rigidity of the seat frame will cause uneven stress on the bolts under the action of external loads.
In order to improve the rigidity of the seat frame, the following aspects can be considered: the support seat should be subjected to sufficient aging treatment to completely release the internal stress;

the seat frame should be made into a hollow cylindrical structure as much as possible, and should have sufficient height; if welding is used For the seat frame, appropriate reinforcing ribs should be set to prevent the horizontal and vertical deformation of the seat frame.

Requirements for the seat frame structure:
1 The seat frame should have sufficient and uniform axial stiffness and horizontal stiffness, that is, the torsion resistance of the support frame must be good.
In order to withstand the axial force greater than the radial force, the car should have sufficient height.

As the external load increases, the diameter of the support will increase, and the elasticity of the seat frame will also increase, so the height of the seat and the diameter of the support should maintain a certain ratio. For cylindrical structures, the recommended diameter to height ratio is between 2.5:1 and 4:1. Regarding the truncated cone and the rectangular frame structure, it can generally be determined with reference to this ratio.

2 The seat frame should be made into a hollow cylinder as much as possible, and the cylinder wall should be arranged close to the raceway, so that the cylinder wall can directly transmit the load.

3. The plane of the seat frame is preferably processed by cutting, and the flange of the centering boss is reserved to prevent the radial side movement of the raceway.
Various 4 point contact ball slewing bearings have different requirements and service life for the installation plane accuracy, the rigidity of the seat frame, the allowable clearance increase in use, and the service life.

4 point contact ball slewing bearing Alt.

3. Faults caused by the flatness of the installation plane and the lack of supporting rigidity

Because the rigidity of the 4 point contact ball slewing bearing itself is poor and the axial bending resistance is weak, after installation, the bearing will deform with the processing quality of the installation plane under the action of the bolt, and the amount of deformation will increase with the reduction of the flatness of the installation plane.

After being loaded, the warping deformation will cause local deformation of the raceway, causing the rolling elements to be stuck when rotating or the bearing to make an impact sound when it rotates, and stress concentration will appear on the edge of the raceway, resulting in early damage to the bearing.

Before the 4 point contact ball slewing bearing is installed, the necessary inspection should be carried out on the mounting plane of the supporting seat. It is required that the supporting seat should not only have sufficient rigidity, but also the connecting surface should be machined, and the surface debris and burrs should be removed.

The technical requirements for the connecting surface of the supporting parts shall comply with the provisions in Table 1. Connection surfaces that cannot be machined shall be made flat by injection molding.

Four failures caused by improper installation

1 Insufficient bolt preload
The slewing bearing is usually fixed on the seat frame with bolts. When installing the bolts, pay attention to the diagonal method of installing the bolts. The pre-tightening force of the bolt should reach about 70% of the yield limit of the bolt.

If the preload is not enough, it is easy to cause the relative dislocation of the inner and outer rings when the bearing is under load, so that the contact angle changes, resulting in uneven loading of the rolling elements or edge stress between the rolling elements and the raceway. For the bearing with ring gear, the meshing clearance and meshing quality of the ring gear will change and the tooth surface will be damaged early.
2. Improper installation of soft belt position
The raceway of the slewing bearing ring is heat treated by surface induction hardening. This process method will produce a soft zone between the beginning and the end of the quenched zone, usually marked with S. When installing, the position of the soft belt should be placed in the non-loading area or the non-regular loading area.

Take a crane as an example, that is, the soft belt of the ferrule should be deviated from the main load direction by 90°, so that it deviates from the maximum load rotation area, so as to avoid the maximum working load at the position of the soft belt, so that the raceway will not be plastically deformed and ensure the use of the bearing. life.

Installation requirements for 4 point contact ball slewing bearings
(1) The accuracy and support stiffness of the installation plane should comply with the relevant regulations.
(2) Open the protective packaging of the slewing bearing in a clean and dry environment; clean each joint surface, remove iron filings, paint and anti-rust oil, etc.
(3) Observe and check whether the seal is still in the correct position, clean the installation plane and matching part of the slewing bearing, and the screw holes on the installation plane must be aligned with the installation holes of the bearing.
(4) High-strength bolts are used for connection; the support and the installation plane should be evenly tightened, and the specified pre-tightening torque should be achieved.
(5) Welding is not allowed on the finished product of the 4 point contact ball slewing bearing to avoid deformation of the bearing (except for the slewing bearing with special welding connection)
(6) On the installation plane, it should be considered that there are radially positioned convex and concave shoulders or fast positioning.
(7) The tempering zone of the support raceway plane surface quenching should be placed in the non-load or non-recurrent load and non-neutral load areas. The tempering belts of the upper and lower rolling rings should be installed staggered by 180°. The tempering belt of the moving rolling ring of lifting and excavating machinery should be placed at an angle of 90° to the direction of the boom; the tempering belt of the fixed rolling ring should be placed in a position with less frequent operation.
(8) In order to ensure the stable operation of the bearing, the rotating driving pinion and the teeth of the ring gear should reach the specified motion accuracy, work stability, contact accuracy and meshing backlash.
(9) After the installation work, the dirt and dust on the 4 point contact ball slewing bearing should be removed, and the exposed parts should be painted with anti-rust paint, and the raceway and gear parts should be painted with grease.

Five faults caused by poor lubrication

Lubrication plays an important role in prolonging the fatigue life of 4 point contact ball slewing bearings and reducing friction, wear and temperature rise. Without proper lubrication, bearings cannot work well, and many bearing damages are related to poor lubrication.

The lubrication of the slewing bearing is mostly grease lubrication, which can not only effectively reduce the friction force, wear and temperature rise on the surface of the friction pair, but also play a role in sealing and rust prevention. Although the working speed of the slewing bearing is not high, most of them work under heavy load, so the poorly lubricated relative moving surfaces are prone to adhesive wear and even burns.

At the same time, most of the slewing bearings work in the open air, and the high temperature and humid environment can cause the rolling elements and raceways to corrode quickly. For the lubrication of the slewing bearing, considering the influence of complex and comprehensive factors, the user can choose the best grease according to the specific requirements.

The lubrication of the raceways and gears of the slewing bearing is to be lubricated with grease. In this way, it can not only reduce the wear on the surface of the friction pair, but also play the role of sealing and rust prevention. In addition, high-pressure oil is also used to lubricate the slewing bearing.

1 Period of regular lubrication
For the slewing bearing raceway working in the environment of -20°~80°C, the maintenance can be carried out according to the following requirements:
(1) Working in an unclean environment and running continuously, lubrication should be carried out every 40 to 50 hours of operation;
(2) Work in an unclean and humid environment and operate intermittently, and lubricate immediately before and after work;
(3) Work in a clean environment and run intermittently, and lubricate every 3 to 6 months.

For slewing bearings that work continuously in high temperature and dusty environments, the lubrication interval should be appropriately shortened. Machines should be lubricated before and after long-term storage. The lubrication of the ring gear and the pinion should be determined according to the condition of the teeth. When the tooth surface is bright, grease is required. Generally, lubricate once every 2 to 3 months.
2 The method of raceway lubrication
(1) Connect the eight lubrication points of the pipeline with the centralized lubrication point, that is, centralized lubrication;
(2) Inject lubricant to the grease nipple of each lubrication point, that is, dispersion lubrication.

When adding lubricant, the bearing should be rotated, and the lubricant should be filled with all the space in the raceway, so that the excess grease can be squeezed out from the labyrinth or the gap of the seal, and the dirt, dust, etc. in the bearing should be taken out.

6. Damage caused by improper sealing

On the one hand, the sealing of the slewing bearing can prevent the leakage of lubricant, and on the other hand, it can also prevent the entry of water, dust and other impurities when used in the open air. If the seal is not good, the grease is not fully filled or leaked, the intrusion of moist air and water can cause the rolling elements and raceways to rust and peel;

The roughness of the working surface will shorten the life of the bearing; if the hard impurities enter the inside of the shaft, they will grind with the raceway and rolling elements, which can cause wear of the bearing, thereby increasing the clearance, or scratching the working surface.

The most commonly used seal is the sealing strip seal. This kind of seal is to process the sealing grooves on the inner and outer rings of the bearing respectively, and then add the sealing strips during assembly. This method can effectively prevent dust and impurities from entering the inside of the bearing, and can also prevent the leakage of lubricant. In some special occasions, the labyrinth seal is more reliable.

Inspection content and countermeasures of seals:
(1) Damage and aging of seals. Seals need to be replaced.
(2) The seal is overstretched and falls off. Need to adjust or reinstall.
(3) The lip of the seal is worn. It is necessary to replace the aged or severely worn seals to increase the lubrication of the lip.
(4) The bearing is in contact with the sealing lip. Contact areas need to be cleaned to remove sharp edges from friction areas.

7. Failure caused by the manufacturing quality of the retainer

The slewing bearing bears a large load and eccentric moment, which causes the uneven force on the rolling elements, which affects the smoothness of the bearing operation, especially in the case of continuous operation and high-speed operation,

it is necessary to design a suitable The retainer, but if the retainer is defective in manufacture, the strength is not enough, and the precision is not high, the retainer will be damaged, resulting in the rolling element stuck and the raceway damaged. Therefore, it is necessary to observe carefully in the daily maintenance, and replace the damaged parts in time if any abnormality is found.

8. Analysis of raceway and rolling element damage

Due to the wrong installation of raceways and rolling elements, overload operation, poor heat treatment, unreliable sealing devices, etc., the raceways and rolling elements will be damaged prematurely. The following lists the typical damage symptoms and introduces the main causes of raceway damage and the impact on the support work.

1 raceway peeling
Raceway spalling is also known as raceway denudation. This phenomenon is generally caused by poor heat treatment. Usually, the surface hardness of the raceway is too high (HRC>60) and the hardened layer is relatively thin, and the interface layer of high hardness and low hardness is caused by the alternating stress.

His characteristic is that the exfoliation is flaky. This kind of damage sometimes occurs at the junction of the tempered soft belt of the raceway.

2 Raceway and roller damage
(1) If the roller is inclined outward or the axis of the rolling ring is skewed, the raceway will be damaged.

In order to prevent the roller end surface from scratching the raceway, the length of the roller in the cross-roller slewing bearing is usually 0.5-1 mm shorter than its diameter. If the roller is shortened excessively or the upper and lower rings are separated due to loose connecting bolts, the gap between the roller end face and the raceway will increase; the skew angle of the short roller can increase the skew angle between the roller end face and the raceway.

If the raceway has defects (low hardness, unevenness, etc.), the edge of the raceway will be damaged due to the increased skew of the rollers, which may cause the rollers to jam along the diagonal line. In addition, if the rollers are stuck in the diagonal direction, the end face chamfers in the diagonal direction of the rollers will be damaged, and even the slewing ring will be braked.

(2) The quenching hardness of the raceway surface is insufficient (HRC<50), which will cause some raceway scratches.

(3) When assembling the support, if the support is accidentally impacted, the roller is skewed and the force is too large during assembly, the raceway of the rolling ring can be damaged.

3 Raceway wear
The causes of raceway wear are as follows:

(1) Due to the dust, sand, dirt and other particles mixed in the lubricating oil, they act as abrasives on the raceways and rolling elements, causing invisible metal peeling or peeling. This kind of wear can be felt in severe cases. Degree. In order to prevent such wear, the bearing should be provided with a reliable sealing protection device to prevent external media such as dust, sand, dirt and moisture from invading and rolling into it.
(2) When there is a lack of lubricating oil or insufficient lubricating oil in the bearing, under heavy load, due to the dry friction or semi-dry friction between the rolling element and the raceway, the raceway wear will be aggravated.
4 Causes of cracks in raceways
(1) The material itself is defective or improperly heat treated.
(2) When the rolling element and the raceway are rotating, the contact fatigue stress is very large, resulting in fatigue cracks.

5 Wear of rolling elements
The cross-roller slewing bearing has many sliding friction surfaces: the friction between the end face of the column and the outer circle on the raceway surface; the friction between adjacent ones.

The latter friction is often point contact at the beginning, the unit contact pressure is high, and it is in a state of dry friction and friction, and friction is generated, but as the contact area increases, the unit pressure decreases, which improves the lubricating strip on the contact surface.

The degree of wear is controlled. After this stage, a wear band with a width of 2~4 mm will be formed on the outer circle of the roller, which does not impair the working ability of the roller and the bearing.

6 steel ball broken
Due to the material or heat treatment defects of the steel balls, as well as foreign objects being trapped or improperly used, the steel balls will be broken, which can be judged from the sudden increase in the rotation resistance of the support and the abnormal sound during rotation.

If it is not eliminated in time, the fragmentation ball can scrape off large pieces of metal in the raceway, and even cause the thickness of the raceway to be reduced. In addition, sometimes the broken steel ball is embedded between other steel balls and the raceway, which will also cause the machine to lose its ability to rotate.

Application example 1: The source of the sound generated by the slewing bearing during operation
During the early use of the excavator, the slewing bearing often produced a loud metal impact sound. Users who use excavators generally believe that the sound when turning comes from the failure of the supporting slewing bearing core, and they are worried that the excavator will have an accident.

The solution to such problems by the after-sales service personnel of excavator manufacturing enterprises is to replace the slewing bearing. Because excavators usually operate in the field, the replacement of the slewing bearing requires a lot of work and requires lifting equipment, which will also seriously affect the construction period.

After visiting the after-sales service personnel and discussing with experts from some main engine manufacturing enterprises, it is believed that the following reasons are the source of the noise when the slewing bearing is used in the early stage.

1. The source of the sound of the slewing bearing during operation
At present, excavators at home and abroad preferentially adopt the structure type of single raceway ball slewing bearing. The rolling elements are separated by nylon material after special treatment, and the annular raceway is completely filled; the rolling elements make pure rolling motion in the raceway.

The commonly used process methods for raceway processing are: raceway forming processing – raceway surface heat treatment – raceway grinding. According to the raceway structure type and processing technology it adopts, it is impossible to produce metal impact sound.

Even if the raceway is crushed due to material and product quality control problems, there will only be excessive running clearance, and the problem can be clearly judged from the outside. The “raceway crush” failure mode produces no sound. Rolling element wear or damage has not been detected from statistical and failure mode studies.

Due to the difference in the selected material, quality and heat treatment process of the spacer block, the spacer block will be deformed and crushed, and the spacer block will be turned over if the reasonable accumulation gap is not adjusted during assembly, causing the rolling element to be blocked from rolling normally in the raceway. The failed isolation block will rub against the raceway under the action of the rolling elements during operation, producing a slight sound of “z-z”.

The single-row ball slewing bearing is loaded with steel balls and fixed. If the gap between the blocked and blocked holes is not well controlled during the manufacturing process, and the edge is not trimmed and the taper pin is not fastened, there will be a “da, da” when the steel ball passes here. continuous and regular sound.

2. When the excavator is assembling the slewing bearing, if the assembly quality is not well controlled during the installation process, it is easy to produce loud noises.

The upper and lower connecting plates for installing the slewing bearing are welded with plates. If the connecting plates are not properly aged, the unevenness of the installation plane after processing exceeds the minimum axial clearance of the slewing bearing from the factory, and the slewing bearing is connected with high-strength bolts.

Deformed, a point is “negative clearance”. This also occurs if there are burrs, iron chips, etc. on the installation plane. Due to the large size of the index circle of the slewing bearing gear, there is a roundness error, and the backlash is not adjusted to a reasonable backlash during installation.

When the large and small gears are in meshing operation, there may be no backlash or “negative backlash” at a certain position. The generation of “negative values” would require a larger driving force to cross these points. As a result, the structural parts of the excavator are twisted, resulting in dislocation of the connection, resulting in a loud metal impact sound.

high speed ball slewing ring bearing in stock

Why do slewing ring bearings need to grind their teeth?

With the continuous development of industrial machinery, there are higher and higher requirements for the transmission stability,

transmission accuracy and bearing capacity of the motor-driven pinion and the slewing ring gear. Regarding the slewing ring bearing,

whether it is external or internal, the normal processes include gear shaping, gear hobbing, and gear milling.

According to the design standards, the general gear accuracy is grade 8 or grade 9.

Rough insertion and fine insertion can reach grade 7 tooth precision. The tooth precision is mainly reflected in the rotation precision. Specific indicators:

1. Cross pitch and common normal length

2. Common normal deviation

3. Tooth jump (tooth jump of finished turntable bearing)

4. Tooth width, tooth thickness, tooth shape and tooth direction, etc. (generally not marked in the drawing)

slewing ring bearing Alt.

In order to improve the strength, hardness, wear resistance and toughness of the ring gear and gear, we usually use surface quenching on the teeth of the ring gear when machining the slewing ring bearingSlewing Bearing teeth. If the tooth quenching is not performed, the overall performance of the ring gear will decrease Easily damaged, etc. Tooth quenching has a great influence on the tooth accuracy.

After quenching, the ring gear will appear elliptical deformation, and the accuracy level will decrease.

If the tooth accuracy requirements are high, the design requirements are usually not met after quenching.

If you want to achieve higher tooth accuracy after quenching, you need to Finishing the teeth, but the hardness of the teeth after quenching is high,

and the conventional gear shaping or gear hobbing process cannot process the quenched teeth.

We usually use the grinding process. What is grinding? The grinding wheel is used as a tool to grind the processed gear tooth surface to improve the gear precision and surface roughness.

It is suitable for steel gears with high hardness after quenching.

Grinding teeth can achieve high surface roughness, and the quenched teeth can reach Ra0.8 surface roughness through grinding, and the tooth jump can reach 0.03-0.1mm. Grinding can correct the deformation of the gear during the heat treatment process, ensure the accuracy of the finished gear, improve the meshing accuracy, achieve the purpose of precise transmission, and reduce vibration and noise.

The slewing ring bearing and gear are ground to improve the roughness of the teeth and improve the accuracy level of the teeth. The grinding teeth can generally reach the 5th or 6th grade tooth accuracy, which provides the precision slewing bearing with the pinion to achieve high precision and small backlash transmission. a solid foundation

slewing bearing factory

What processes are included in the heat treatment of slewing bearings?

The function of the heat treatment of the slewing bearing is to improve the mechanical properties of the material, eliminate the residual stress and improve the machining performance of the metal. Different heat treatments are adopted at different stages in the processing of the slewing bearing. Commonly used are annealing, normalizing, aging, modulation, Quenching, nitriding, etc., let’s briefly introduce each heat treatment process.

slewing bearing Alt.

1. Annealing
The process of heating the forging of the slewing bearing to a certain temperature and keeping it for a long time and then slowly cooling it, the main purpose is to release the residual stress during forging, increase the toughness of the forging, reduce the hardness of the forging to facilitate subsequent processing, and improve the internal structure of the forging. Refine grains and enhance the mechanical properties of forgings.

2. Normalizing
The slewing bearing forgings are heated to a temperature of 30~50°C exceeding the AC3 temperature, and they are cooled after a period of heat preservation. After they are released, they need to be cooled quickly. Generally, water spray, spray or air cooling are used.

Because they do not need to be cooled with the furnace, and accelerated cooling is adopted. Measures, the heat treatment efficiency is higher, the grains of the forgings after normalizing are more refined and the distribution is more uniform, which can improve the comprehensive mechanical properties of the forgings, improve the cutting performance of the forgings, and make the forgings easier to process.

3. Aging
The process of placing the machined slewing bearing ferrule at a higher temperature or room temperature for a period of time to release the internal stress and fully deform the ferrule. The aging at a certain higher temperature is called artificial aging, and the aging in the natural state is called natural aging. Artificial aging generally heats the ferrule to about 150 ℃ and keeps it for about 12 hours, which can eliminate the internal stress of the ferrule and make the ferrule more stable. effect.

Generally, aging treatment is carried out after rough machining and heat treatment of the slewing bearing ring. For precision slewing bearings, almost every process is processed, an aging treatment will be carried out. On the one hand, it can ensure high machining accuracy and prevent machining deformation. In terms of fully eliminating the internal stress of the slewing bearing to ensure that the slewing bearing will not be deformed after delivery, affecting the accuracy.

4. Modulation
The rough processed slewing bearing forgings are first quenched and then subjected to a heat treatment process of high temperature tempering. The quenching temperature and tempering temperature are determined according to the size of the ferrule and the specific hardness and mechanical properties. Generally, the ferrule is heated to 850 °C for a period of time, and then quenched. The quenching medium is generally oil or water medium.

After quenching High temperature tempering, the ferrule is heated to 630 ℃ for a period of time and then air-cooled. The slewing ring has excellent comprehensive mechanical properties after modulation, and the strength and toughness are well matched, with high strength, excellent toughness, plasticity, cutting performance, etc.

5. Quenching
Quickly heat the surface of the channel or tooth of the slewing bearing to the quenching temperature, and then immediately use the quenching liquid to cool the heating part. After cooling, the surface of the channel and tooth is hard, the core is soft, and the surface is wear-resistant and anti-fatigue.

High toughness, good impact resistance. Quenching not only makes the channels and teeth of the slewing bearing firm and wear-resistant, but also increases the load of the channels and teeth, and improves the comprehensive performance of the slewing bearing.

6. Nitriding

Nitriding is a method of infiltrating nitrogen atoms into the metal surface to obtain a layer of nitrogen-containing compounds. Nitriding layer can improve the hardness, wear resistance, fatigue strength and corrosion resistance of the part surface. Because the nitriding temperature is low, the deformation is small, and the nitriding layer is thin (generally no more than 0.6~0.7mm), the nitriding process should be arranged as far back as possible. In order to reduce the deformation during nitriding, it is generally necessary to High temperature tempering for stress relief.

Lower Price Slewing bearing shaking

What is the reason for the overturning and shaking of the slewing bearing?

With the rapid development of the machinery industry, slewing ring bearings have been widely used in marine equipment, construction machinery, light industrial machinery, metallurgical machinery, agricultural machinery and other industries. In the process of installation and use, improper use or maintenance of the slewing bearing may bring about various problems. For example, in the use of the slewing bearing, there is a problem of excessive overturning and shaking. What is going on?

1. The mounting bolts are loose, resulting in excessive overturning and shaking during work. When the slewing bearing is shaken, the connecting bolts should be considered first. All the connecting bolts of the inner and outer rings should be checked immediately to see if there is any looseness. If there are any, tighten them according to the torque requirements.

2. The rigidity of the steel structure supporting the slewing ring bearing is insufficient, and elastic deformation occurs when the slewing bearing is under heavy or eccentric load, resulting in the overall overturning and shaking of the slewing ring bearing. This problem is solved by reinforced steel structure.

3. Check whether the operation is seriously overloaded. Overloading will also cause the slewing ring bearing to shake too much, so it must be operated strictly and reasonably according to the regulations.

4. Long-term overload or severe eccentric load operation will cause the raceway to be crushed by the rolling elements, resulting in excessive clearance beyond the normal range. If such a situation occurs, the problem is more serious, and it is necessary to contact the slewing ring bearing manufacturer to solve it in time to ensure the normal use of the bearing.

In order to ensure the normal use of the slewing ring bearing, the use and maintenance should be carried out in strict accordance with the “Installation and Operation Manual”. If there is a serious phenomenon of overturning and shaking during use, it must be stopped in time for inspection to prevent long-term sick operation to the slewing ring bearing. cause more damage.

slewing bearing Alt.

2.How can we increase the service life of the slewing bearing?

Regarding the installation of the slewing bearing, first of all, the stop should be in place, the installation holes should be aligned, and the bolts should be pre-tightened first, and then tightened according to the diagonal method with reference to the tightening torque of different bolts. In fact, there are two main points to pay attention to the installation of the slewing bearing, the first is the installation platform, and the second is the installation method.

The installation platform of the slewing bearing must first have sufficient strength support, and secondly, it must have sufficient flatness. Many people have no problem with the strength of the bearing, but often ignore the flatness of the installation surface. The general accuracy of the slewing bearing produced by Fuji Transmission Higher, the requirements for the flatness of the mounting surface are also higher.

If the flatness of the mounting surface is greater than the parallelism of the slewing ring bearing, when the bolts are tightened, the accuracy of the slewing bearing will be lost, and the slewing bearing will be deformed, and the grooves will be deformed. The dislocation of the slewing ring bearing reduces the service life of the slewing bearing, and the installation platform of the slewing ring bearing is generally machined.

When installing the slewing bearing, check the flatness. For defective positions, you can use the method of adding gaskets. The bonding surface of the slewing bearing and the installation platform should be clean and free of particles and other debris.

The slewing bearing has the position of the soft belt when it leaves the factory, which is generally marked as S. The plug is always the position of the soft belt. When installing the slewing bearing, special attention should be paid to the position of the soft belt. The position of the soft belt should be adjusted to the non-load area or not often.

In the load area, the soft belt area of the inner ring and the outer ring of the slewing ring bearing should be staggered by 180°. When installing slewing ring bearings on some lifting equipment such as truck cranes, cranes and tower cranes, the position of the soft belt should be installed at 90° to the boom.

For the slewing bearing with teeth, the highest position of the tooth runout is generally sprayed with colored paint. Use this position to cooperate with the pinion, and adjust it with a feeler gauge according to the requirements of the national standard.

cheap crossed roller slewing bearings manufacturers china

Crossed Roller Slewing Bearings

A crossed roller slewing bearing is a special type of bearing with a split inner ring and a rotating outer ring. Since the divided inner ring or outer ring is installed with the roller and spacer, it is fixed with the cross roller ring to prevent separation from each other, so it is easy to install the cross roller ring.

Since the rollers are arranged in a cross, only one set of Crossed Roller Slewing Bearings can withstand loads in all directions, and the rigidity is 3 to 4 times higher than that of conventional models. At the same time, since the inner ring or outer ring of the crossed roller slewing bearing is divided into two structures, the bearing clearance can be adjusted, and even if a preload is applied, high-precision rotational motion can be obtained. Moreover, due to its special structure, it is usually used as a joint bearing in industrial robots.

Their rollers are arranged at right angles to each other at intervals between the inner and outer wheels. They can bear loads from all directions at the same time (such as axial, thrust or momentum loads, etc.). Because the rollers are in linear contact with the track surface, the possibility of elastic deformation of the bearing under load is very small.

This type of bearing is widely used in such occasions as industrial automatic robots, working machinery and medical facilities, etc., where high rigidity, tightness and high speed are required to ensure accuracy.

In a crossed roller slewing bearing, since the cylindrical rollers are arranged perpendicular to each other through spacers, a single crossed roller bearing can withstand loads in all directions, including radial load, axial load, and moment load.

The size of the inner and outer rings is minimized, especially the ultra-thin type is a small size close to the limit, and has high rigidity, so it is most suitable for the joint part or rotating part of industrial robots, the rotary table of machining center, It is used for robot rotating parts, precision rotary tables, medical equipment, measuring instruments, IC manufacturing equipment, etc.

Use features
For crossed roller bearings, since the divided inner ring or outer ring is installed with the rollers and spacers, it is fixed with the crossed roller collar to prevent separation from each other, so it is necessary to install the crossed roller collar.

Simple. Since the rollers are arranged in a cross, only one set of Crossed Roller Slewing Bearings can withstand loads in all directions, and the rigidity is 3 to 4 times higher than that of conventional models. At the same time, since the inner ring or outer ring of the crossed roller bearing is divided into two structures, the bearing clearance can be adjusted, and even if a preload is applied, high-precision rotational motion can be obtained.

crossed roller slewing bearing Alt.

1. Excellent rotation accuracy

The internal structure of the crossed roller slewing bearing adopts the rollers arranged at 90° perpendicular to each other.

There are spacers or spacers between the rollers, which can prevent the rollers from rubbing against each other due to the inclination of the rollers. In addition, there is no contact phenomenon or locking phenomenon of one side of the roller; at the same time, because the inner and outer rings are divided structures, the gap can be adjusted, and even if a preload is applied, high-precision rotational motion can be obtained.

2. Simplified operation and installation

The outer ring or inner ring, which is divided into two parts, is fixed together after the rollers and cages are installed, so it is very easy to install.

3. Bear large axial and radial loads

Because the rollers are arranged perpendicular to each other on the 90° V-groove running surface by spacers.

4. Significantly save installation space

The size of the inner and outer rings of the crossed roller bearing is minimized, especially the ultra-thin structure is a small size close to the limit, and has high rigidity, so it is most suitable for the joint parts or rotating parts of industrial robots, and the rotation of machining centers. Widely used for worktables, manipulator rotating parts, precision rotary tables, medical instruments, measuring instruments, IC manufacturing equipment, etc.

5. High speed capability

6. Reduced shaft length and machining cost, limited change in geometry due to thermal expansion

7. Using nylon divider, low moment of inertia, low starting torque, easy to control angle indexing

8. Optimized pre-tightening force, high rigidity and high running accuracy of guide rollers

9. Carburized steel provides excellent impact resistance and surface wear resistance

10. Simple but well lubricated

Classification and Model Series of Domestic Crossed Cylindrical Roller Bearings

RB type (outer ring split type)

The RB series is the basic type of the crossed cylindrical roller bearing. The size of the inner and outer rings is minimized. Its structure is that the outer ring is a split type, and the inner ring is an integral design, which is suitable for parts that require high rotation accuracy of the inner ring. .

RE type (inner ring split type)

The RE series model is a new type produced by the design concept of the XRB type, and the main dimensions are the same as the XRB type. Its structure is that the inner ring is a split type, and the outer ring is a one-piece design, which is suitable for parts requiring high rotation accuracy of the outer ring.

RU type (inner and outer ring integrated type)

The RU series model does not need a fixed flange and a support seat due to the machining of the mounting holes. In addition, since the integrated inner and outer ring structure with seat is adopted, installation has little effect on performance, so stable rotation accuracy and torque can be obtained. Can be used for outer and inner ring rotation.

RBC type (outer ring split type)

The RBC series model (corresponding to the CRBC series of IKO company) has a structure that the outer ring is a split type, the inner ring is an integral design, and a full complement roller bearing with a cage. It is suitable for parts that require high rotation precision of the inner ring.

CRBH type (inner and outer ring integrated type)

The inner and outer rings of the CRBH series are of one-piece structure for rotation of the outer and inner rings.

RA type (outer ring split, ultra-thin type)

The RA series model is a compact model that reduces the thickness of the inner and outer rings of the RB type to the limit. Ideal for applications requiring a lightweight, compact design, such as robotic and manipulator rotation.

SX type (outer ring split type)

The structure of the SX series is similar to the RB series. The outer ring is a two-part structure, connected by three spring snap rings, and the inner ring is designed in one piece, which is suitable for places requiring high rotation precision of the inner ring.

XRU08 type (integrated type of inner and outer rings)

The XSU08 series is similar to the RU series, and the inner and outer rings have been processed with mounting holes, so there is no need for a fixed flange and a support seat. Due to the integrated inner and outer ring structure with seat, installation has little effect on performance, so stable rotation accuracy and torque can be obtained. Can be used for outer and inner ring rotation.

First thrust angular contact ball bearing
The contact angle of thrust angular contact ball bearings is generally 60°. Commonly used thrust angular contact ball bearings are generally bidirectional thrust angular contact ball bearings, which are mainly used for precision machine tool spindles. It has the advantages of high precision, good rigidity, low temperature rise, high speed, and convenient assembly and disassembly.

Second deep groove ball bearing
Structurally, each ring of a deep groove ball bearing has a continuous groove-type raceway with a cross-section of approximately one third of the equatorial circumference of the ball. Deep groove ball bearings are mainly used to bear radial loads, and can also bear certain axial loads. When the radial clearance of the rolling bearing increases, it has the properties of an angular contact ball bearing and can bear axial loads alternating in two directions.

Compared with other types of bearings of the same size, this type of bearing has a small friction coefficient, high limit speed and high precision, and is the preferred bearing type for users when selecting models. Deep groove ball bearings have a simple structure and are easy to use. They are the type of bearing with the largest production volume and the widest application range.

Third thrust tapered roller bearing
Since the rolling elements in the thrust tapered roller bearing are tapered rollers, the rolling busbar and the raceway busbar of the washer meet at a certain point on the axis of the bearing, so the rolling surface can form pure rolling and high limit speed. for thrust cylindrical roller bearings. Features: Thrust tapered roller bearings can withstand unidirectional axial loads. The type code of thrust tapered roller bearing is 90000 type.

Introduction to Crossed Cylindrical Roller Bearings

There are two types of crossed roller slewing bearings, one is crossed cylindrical roller bearings, the other is crossed tapered roller bearings; crossed roller bearings have a long history of application abroad, but only recently in China. It has only entered the public’s vision for a few years, and it is widely used due to its own particularity and incomparable advantages over other bearings.

high quality china cross roller slewing rings supplier

What is called cross roller slewing rings?

Cross roller slewing rings are bearings for high-precision applications whose dimensions conform to ISO dimension series 18 as per DIN 616. They comprise outer rings, inner rings, rolling elements and plastic spacers. The outer ring is split and is held together by three retaining rings.

Due to the X arrangement of the cylindrical rollers, these bearings can support axial forces from both directions as well as radial forces, tilting moment loads and any combination of loads by means of a single bearing position. As a result, designs involving two bearing positions can be reduced to a single bearing position.

Crossed roller slewing rings are very rigid, have high running accuracy and are supplied with normal clearance, low clearance or preload. The bearing outer rings are easily fixed to the adjacent construction using clamping rings.

The basics cross roller slewing rings

Cross roller slewing rings provide more accuracy, rigidity, and weight-bearing capacity for linear motion than other commonly used friction-reducing devices such as ball bearings. And unlike ball bearings, they can support moment loads, radial forces or tilting loads. This lets one crossed roller bearing replace more than one ball bearing, thus saving the space required by ball bearings, lowering the associated material costs.

Cross roller slewing rings are preferred for high-precision linear-motion applications with relatively short linear movements that require smooth motion. They are also durable, lasting 150 million cycles, even for linear-motion applications with high levels of acceleration and deceleration when using 2 to 12-mm rollers and 30 to 600-mm lengths.

They can be found in medical and lab equipment, machine tools, semiconductor processing, clean rooms, vacuum environments, material handling, and automation machinery. And as technology becomes more demanding, requiring greater and greater precision, crossed roller bearings will also become more common.

cross roller slewing ring Alt.

Crossed Roller slewing ring Basics

A crossed roller slewing ring, also called a crossed roller slideway, is effectively two sets of bearings and races combined at right angles to each other. Cylindrical bearings or rollers mount along the length of a rail in a carriage. The rollers are held in place with a cage, preventing roller-to-roller contact, which increases friction and wear. Keeping rollers separated also eliminates any risk of them jamming.

If you were to number the cylindrical rollers along the rail, the even ones would be mounted at 90° to the odd ones. In other words, the rollers alternate orientation.

This lets the line of alternating rollers support loads from all directions, including high overturning moments, and because they do not recirculate like some ball bearings that line linear rails, all the rollers are constantly carrying the load except for pure radial loads, where, due to the criss-cross arrangement, only half of the rollers take loads at any one time.

The cylindrical rollers are mounted such that they create a protruding V-shape on the sliding rail. It fits into a corresponding V notch in the other rail that is likely carrying
the load.

Rollers provide a full line of contact rather than just the point of contact a ball bearing provides. This gives cross roller ring a broader contact surface and the ability to carry heavier loads. It also increases the bearing’s rigidity so it deforms less and is thus more accurate. Plus, erosion is slower due to the crossed rollers’ consistency of contact between the carriage and the base.

There is a direct correlation between the combined contact area of all the rollers and load capacity: the greater the area, the higher the capacity. This lets bearing designers adjust load capacity by up to 250% by mounting rollers closer together. This permits more rollers to fit in the same space and increases the amount of weight per inch the bearing can carry.

Cross roller slewing ring do not use seals due to their construction, high precision, and low friction. Still, it is important to keep contaminants away from the rollers to prevent damage and wear. One way this is done, especially in IC manufacturing and lab equipment, is to install the machines using cross roller slewing rings in clean, contamination-free environments.

It is also important to lubricate crossed roller slewing rings to get the most operational life out of them. A standard lubricant for them is lithium-soap-based #00 grease.

The configuration of crossed roller bearings gives designers all the benefits of a two-row bearing, including stability, in a single-row space.

Accuracy and Rails

Because of crossed rollers large contact area, they deform less than recirculating ball bearings and are stiffer, creating more precise and consistent motion. Because of this greater stiffness, crossed rollers provide consistently precise movement.

Cross roller slewing ring are less forgiving of mounting surface inaccuracies than recirculating ball bearings due to their rigidity and the way they are designed. Ball bearings can handle imperfections on the order of five to ten 10 microns while crossed roller bearings need imperfections smaller than two microns for ultra precision.

Metal and Plastic Cages

One factor that determines how close rollers can be to each other is the cage (or retainer) holding them all in place, so its design is critical. An important factor in the design of the cage is whether it is made of metal or plastic.

Traditional metal cages use tabs on the carriage that fit into notches on the top and bottom of the rollers to keep them in place. This limits how closely a roller can be positioned between neighboring rollers, which then limits the crossed roller bearing’s load-carrying capacity.

But metal cages are less expensive and can be plain or stainless steel. Metal is more compatible with working in vacuums, including outer space, because plastic can out-gas and cause problems with electronics and optics. Stainless steel can also be beneficial in high-temperate applications and those requiring washdowns and where rust is unacceptable.

Plastic cages fit smoothly around each roller, exposing more of it to the load than a metal cage can. Plastic cages also pack rollers closer together so more rollers can be housed in the same rail. These two features mean the cage and rollers can be shorter while maintaining the same load capacity or the number of rollers can be increased within the same cage (compared to a metal version) and thus increase the load capacity.

In fact, a plastic cage can yield a 30% to 58% increase in contact area compared to a metal cage. This increase translates to a 250% increase in load capacity.

Recent development in plastic cages has increased the number of design options available to engineers. They can now be shaped so that there’s even a larger contact area with less space between rollers. Plastic cages can also be thinner in critical areas.

cylindrical rollers slewing ring factory

1.What are the characteristics of cylindrical rollers slewing ring?

Cylindrical roller slewing ring is a kind of crossed roller bearing, which is mainly composed of two races, single row of crossed cylindrical rollers, cage (isolation block), sealing device and other parts.

It is widely used in the waist rotation of robots such as handling and palletizing, rotary disks with high precision and rigidity on automation lines, welding station turntables, large-diameter rotary disks, tower cranes with medium and above diameters, and truck cranes.

1. Can carry loads in all directions

The cylindrical rollers slewing ring has only one row of rolling elements, but the rolling elements are short cylindrical rollers. The axes of the adjacent rollers are arranged in a 90° cross arrangement. There are two raceways in the inner and outer rings.

Axial force, half bear the upward axial force, this bearing can bear radial force, axial force and overturning moment. Usually the length of the cylindrical roller should be 0.5~1mm shorter than its diameter. The integral structure is simple and rigid.

2. Isolation block

The cylindrical rollers slewing ring can be with or without spacer. Most of the foreign ones used in construction machinery do not have isolation blocks.

3. Adjustable clearance

Most of the cylindrical rollers slewing ring are made of split type, which is convenient for installing rolling elements and adjusting the clearance. But there are also integral ones, like four-point contact balls, which use filling holes to fill the rollers, and use options to adjust the axial clearance. After the rollers are full, some clearance is also required, and the total clearance between the rollers is usually about 0.5d in the circumferential direction.

4. Effectively prevent the increase of rotational torque

The internal structure of the cylindrical rollers slewing ring adopts the rollers arranged perpendicular to each other at 90°, and the spacers or spacers are installed between the rollers, which can prevent the inclination of the rollers and the mutual abrasion between the rollers, effectively preventing the An increase in rotational torque. In addition, there is no contact phenomenon or locking phenomenon of one side of the rollers.

5. High-precision rotation

Non-standard cylindrical rollers slewing ring, at the same time, because the inner and outer rings are divided structures, the clearance can be adjusted, and even if preload is applied, high-precision rotational motion can be obtained.

6. Easy to operate

The divided inner ring or outer ring, after the rollers and spacers are installed, are fixed with the cross-roller ring to prevent them from separating from each other, so the operation when installing the cross-roller ring is very simple.

7. Prevent the roller from falling sideways

The mutual friction between the rollers is eliminated by the spacer, and the rollers are prevented from falling sideways, so that a stable rotational torque can be obtained.

8. Greatly improved rigidity

Different from the use of double-row thin angular contact ball bearings, since the rollers are arranged vertically and crossed, only one crossed roller collar can bear loads in all directions, and the rigidity is

increased by more than 3 to 4 times.

Bulk Truck Crane Slewing Bearing

1.Causes and anti-rust methods of slewing bearing rust

Slewing bearing is a kind of large bearing with special structure. It is widely used in many construction machinery or equipment platforms. If the bearing is stored or used improperly, it may cause rust, which will affect the use effect.

The cause of corrosion

1. The relative humidity is too high

The relative humidity we often say refers to the ratio of the water vapor content in the air to the saturated water vapor content of the air at the same temperature, usually expressed as a percentage. The relative humidity is proportional to the humidity in the air. The higher the relative humidity, the faster the metal corrosion. In general, the critical relative humidity of steel is 70%.

2. The temperature increases to speed up the chemical reaction

When the air is humid, the metal will interact with the oxygen and water in it. Above the critical temperature, condensation will form on the metal surface, resulting in corrosion. If the relative humidity reaches the critical humidity of the metal, the effect of temperature will change.

Obviously, as the temperature increases, the reaction speed continues to accelerate, resulting in corrosion of the bearing.

3. The effect of oxygen

Oxygen can be dissolved in water during the storage process of the slewing bearing. The corrosion phenomenon of oxygen concentration difference is relatively common, and the solubility of different parts will change.

When the bearings are stacked, the oxygen is insufficiently inflated in the middle of the overlapping surface, the concentration in the water is low, the oxygen at the edge is sufficient, and the concentration in the water is high, which will cause rust around the edge of the overlapping surface.

4. Effects of pollutants in the atmosphere

The atmosphere contains a variety of pollutants, such as carbon dioxide, nitrogen oxides, carbon dioxide and other gases and solid dust. These pollutants will condense on the metal surface together with the water mist in the air, and dissolve in water to produce the following results: various non-metallic oxides dissolve in water to become acids, which will destroy the passive film on the metal surface and cause

rust.

slewing bearing Alt.

2. Anti-rust method

1. Immersion method

After cleaning the slewing bearing, it is immersed in a solution of 5% sodium nitrite and 0.6% sodium carbonate. The anti-rust effect is good, but many anti-rust tanks and other equipment are required, which take up a lot of space and are inconvenient to manage.

2. Spray method

Use filtered compressed air with a pressure of about 0.7Mpa to spray in a clean air place. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, and fire protection and labor protection measures are required.

3. Use special rust remover for bearings

The special rust remover for bearings is a rust removal product that can remove rust but does not damage the material of parts. After rust removal, it can maintain the original color of the product metal.

2.Crane Slewing Bearing

Cranes are robust machines with a wide range of motion and high load capabilities. Slew rings play a valuable role in crane operation, which is why durable designs and regular maintenance are vital to a ring’s overall function.

At LYMC, our slew rings for cranes, and various other applications, offer durability from beginning to end. With regular maintenance, our components are a cost-effective solution for any design.

The Function of a Crane Slew Bearing

In lifting equipment like cranes, slew rings create a joint between the undercarriage and the upper structure of the machine. These slewing bearings allow cranes to turn 360 degrees while supporting other diverse movement requirements, from thrust and radial motion to tilting.

The slewing ring’s open design allows hydraulic systems and other control components to pass through the ring for more efficient use of space.

Slew rings play a critical role in crane operation due to their many responsibilities. While crane slewing bearings regulate many movement types, they also withstand the weight of the equipment and its various loads, including payload and counterbalance.

Since cranes are rated at their maximum capable lifting load, it is important to review how far away from the center of the crane this load can be lifted. This is directly related to the crane slew bearing and is referred to as “Tiling Moment Capacity.”

A crane may have multiple vital components for its operation, but a slew ring is the most critical component in designing a crane load chart. Overall, the slew ring will reflect how much load a crane can lift, and the allowed distance where this load can be lifted at safe operating conditions.

roller bearing slewing ring china

Assembly process and detailed steps of slewing ring

Correct placement of internal and peripheral. First, lay the external cause flat on the workbench, put it into the lower half of the inner trap, and try to make the outer raceway correspond to the internal channel.

Correct placement of rollers and spacers. Put the selected cylindrical rollers and circular spacer blocks along the road. When placing adjacent cylindrical rollers, their axes are perpendicular to each other, and the two rollers are separated by a spacer block.

Gently and evenly run the appropriate grease onto the raceway. Fill the gap between the roll and the spacer block. The number of rollers and spacer blocks is generally equal, and the cylindrical dredger and spacer block should be close to each other。

If there is a gap between the roller and the spacer block at the last position, the thickness of one or two spacer blocks can be adjusted to make up for it. gap.

slewing ring Alt.

Install screws or bolts. Tighten the two diametrically opposite mounting bolts 1-2 turns while turning the other integral ferrule to prevent the rollers from getting stuck in place.

Then twist two symmetrical studs 180 apart, and so on, until all bolts are torqued to the specified torque value. When tightening the bolts, make sure the tabs are not in place, and preferably use a dynamometer wrench so that the bolts get the specified pre-tightening torque.

Adjust the no-load slewing ring resistance torque of the support. It may be difficult to turn the turntable bearing ring due to the preload. In the absence of other test equipment, a simple method can be used to test.

That is, a solid angle iron or steel pipe is used as a lever, which is stuck between two diametrically opposite bolts, and one end of the lever is pulled by a spring balance to make the imported bearing ring rotate, so as to be determined by the reading of the spring balance and the length of the lever.

Starting friction torque when the slewing ring is unloaded. The starting friction torque is determined in advance according to the preload of the slewing ring. If it still does not turn, it may be that the roller is stuck. At this time, the bolts should be loosened until the sleeve can be rotated, and then the bolts should be tightened.

Install the adjusting shims Install the adjusting shims above the mounting bolt holes, and the thickness of each group of adjusting shims should be equal.

Put the top half of the inner ring on, be careful at this time, do not move the adjustment tab. The starting friction moment under preload can be verified by the method of lever and spring balance described above.

The actual short turn is equal to the product of the load value indicated on the spring balance and the vertical distance from the spring balance to the center of rotation.

If the torque is too small, disassemble the slewing ring if necessary, and take out some adjustment pieces of equal thickness from each group of adjustment pieces. This procedure may be repeated many times until the China LYMC slewing ring obtains a suitable preload.

The threaded part of bolts and screws should be coated with anti-loosening glue. The lip seal is installed, and the lip seal has an overall annular shape, or it is formed by rolling the long material into an annular shape.

slewing ring bearing for sale

1.What is the difference between a slewing ring bearing and a slewing bearing?

1. Different concepts

1. Slewing ring bearing

The slewing ring bearing is a new type of mechanical parts, which consists of inner and outer rings, rolling elements, etc. The slewing ring bearing is a large bearing that can withstand comprehensive loads, and can bear large axial and radial loads and overturning moments at the same time.

2. Slewing bearing

Slewing bearing is a kind of large bearing with special structure that can bear large axial load, radial load and overturning moment and other comprehensive loads at the same time.

slewing ring bearing Alt.

Second, the structure is different

1. Slewing ring bearing

Slewing drive is usually composed of worm, slewing bearing, housing, motor and other components. Since the core component adopts slewing bearing, it can bear axial force, radial force and tipping moment at the same time. There are many forms, but the structure and composition are basically the same.

2. Slewing bearing

A slewing bearing is usually composed of four major components: inner ring, outer ring, rolling elements, and spacer blocks. Because the core component adopts slewing bearing, it can bear axial force and radial force at the same time. There are many forms, but the structure and composition are basically the same.

Three, different applications

1. Slewing bearing

Slewing ring bearings are widely used, and construction machinery is the first and most widely used place for slewing bearings, such as earth-moving machinery, excavators, disintegrators, stackers and reclaimers, graders, road rollers, dynamic compactors, rock drilling machinery, roadheaders, etc.

Others include concrete machinery: concrete pump truck, concrete mixing and placing boom integrated machine, belt placing machine Feeding machinery: disc feeder, sand mixer; lifting machinery: wheel crane, crawler crane, door Pedestal cranes, tower cranes, fork cranes, hoists, gantry cranes.

Ground treatment machinery: impact reverse circulation drilling rig, rotary drilling rig, impact rotary drilling rig, rotary drilling rig, reverse circulation rotary drilling rig, positive circulation rotary drilling rig, long spiral engineering drilling rig, diving engineering drilling rig, static pile driver, pile driver .

Engineering ships: dredgers; special vehicles: bridge inspection vehicles, fire trucks, window cleaning machines, flat beam transport vehicles, aerial work vehicles, self-propelled aerial work platforms; light industrial machinery: beverage machinery, bottle blowing machines, packaging machinery, Filling machine, rotary unscrambler, injection molding machine; marine crane: floating crane.

2. Slewing bearing

Slewing bearings are widely used, and construction machinery is the first and most widely used place for slewing bearings, such as earth-moving machinery, excavators, disintegrators, stackers and reclaimers, graders, road rollers, dynamic compactors, rock drilling machinery, roadheaders, etc.

Slewing ring bearings are also called slewing bearings, and some people also call them: slewing bearings and slewing bearings.

The English names are: slewing bearing, slewing ring bearing, turntable bearing and slewing ring.

Slewing bearing, also known as slewing bearing, is a large bearing that can bear large axial load, radial load and overturning moment at the same time.

The slewing bearing generally has mounting holes, internal gears or external gears, lubricating oil holes and sealing devices, so that the main engine has a compact design, reliable guidance and convenient maintenance.

Slewing bearings include gearless, external gear and internal gear four-point contact ball bearings, double-row angular contact ball bearings, crossed cylindrical roller bearings, crossed tapered roller bearings and three-row cylindrical roller combined slewing bearings, etc.

Various structural types. Among them, the four-point contact ball bearing has a higher static load capacity; the crossed cylindrical roller bearing has a higher dynamic load capacity; the crossed tapered roller bearing can make the bearing have greater support rigidity and higher rotation through pre-interference precision.

Slewing bearings are widely used in large-scale slewing devices such as lifting machinery, mining machinery, construction machinery, port machinery, marine machinery, and high-precision radar machinery and missile launchers.

Slewing bearing is a kind of large bearing that can bear comprehensive load, and can bear large axial, radial load and overturning moment at the same time.

Slewing ring bearings generally have mounting holes, internal or external gears, lubricating oil holes and sealing devices, so that the design of the main engine can be compact, easy to guide, and easy to maintain.

The slewing ring bearings include four-point contact ball bearings with no gears, external gears and internal gears, double-row angular contact ball bearings, crossed cylindrical roller bearings, crossed tapered roller bearings and three-row cylindrical roller composite bearings.

series, in which the four-point contact ball bearing has a high static load capacity, the crossed cylindrical roller has a high dynamic load capacity, and the pre-interference of the crossed tapered roller bearing can make the bearing have greater support rigidity and rotation accuracy,

The three-row cylindrical roller combination bearing leads to the height of the bearing due to the improvement of the bearing capacity, and various forces are borne by different raceways, so under the same force, the bearing diameter can be greatly reduced, so the main engine is more compact.

A high load capacity slewing ring bearing. Slewing ring bearings are widely used in large-scale slewing devices such as hoisting machinery, mining machinery, construction machinery, port machinery, marine machinery and equipment, as well as high-precision radar machinery and missile launchers.

At the same time, it can also design, develop and produce various special structure slewing ring bearings according to the specific requirements of users. The basic structure of the slewing ring bearing.

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