high precision roller slewing rings factory

1.Selection and use of slewing ring of pile extractor

A pile puller is a pile machine that uses vibration, static force or hammering to pull the pile out of the ground. Pile pulling operations often use the corresponding vibratory pile driver, static pile driver or double-acting steam hammer, together with pile frame and rigging, so it is also called vibratory pile driver and static pile driver.

1. Selection of slewing ring for pile extractor

The slewing ring of the pile extractor realizes the rotation of the device through the action of friction and lubrication. In the pile extractor, it can drive the mechanical rotation and provide support capacity. It mainly plays the role of rotation and support, and must withstand axial, radial, overturning and impact.

Due to the relatively high quality requirements of the slewing bearing, the double-row ball slewing ring is generally selected when selecting the type of slewing bearing. This type of slewing bearing has a tight structure and can withstand large axial forces and tipping moments. slewing ring Alt.

2. How to use the slewing bearing of the pile extractor

The slewing ring of the pile extractor is similar to the use method of the pile driver and the excavator. The slewing bearing is a force transmission element for the relative slewing motion of the upper body and the lower body, which is used to support the mass of the upper body and bear the working load.

The inner race is connected to the lower body, the outer race is connected to the upper body, and the inner gear on the inner race is engaged with the rotary motor pinion. When the slewing motor rotates, the upper body is driven to rotate through the pinion. The slewing ring of the pile extractor uses an internal tooth slewing ring. Because of the impact load, the tooth surface is generally quenched.

It is common for pile extractors to extract piles by vibration. During operation, the vibration pile extractor is fixed on the pile head, suspended under the hook through the spring vibration absorber and rigging, and the pile extractor is started, and the vibration generated by the vibrator is generated. , causing the pile and the soil to resonate, the soil structure is damaged, the friction between the pile and the soil is reduced, and the rigging is tightened to gradually pull out the pile.

If an eccentric block vibrator is used, the eccentric block must be adjusted due to the different resistance directions of pile driving and pile pulling. This kind of pile pulling equipment has the advantages of simple structure, high pile pulling efficiency and promising development.

The hydraulic pile puller uses its pile clamp to clamp the pile head, and the hydraulic cylinder forcibly presses the pile clamp to lift it upward for a certain distance, and pulls out the pile section by section. It is suitable for clay, sandy soil or soil containing a small amount of gravel.

Pull out I-beam or section steel piles in the layer. There is also a mechanical method of pulling the pile, that is, the hoist is driven by the motor, and the pile is forcibly pulled out of the ground by the pulling force of the wire rope pulley. It is easy to use and low in cost, but the pile pulling force is not large, the equipment is cumbersome, and the pile pulling efficiency is low.

It is only suitable for construction in soft soil. Use the double-acting steam hammer to pull out the pile. The hammer body is inverted, fixed on the pile head, and suspended under the rigging. First, shake the pile head in the soil to reduce the tightness between the pile and the soil, and then start the steam hammer to hammer upward. Vibrate, tighten the rigging, and gradually pull out the pile, which can pull concrete piles and other piles in various soil layers.

2.Strengthen the use effect of slewing ring from 3 aspects

1. During the use of the machine, we should add lubricating oil to the bearing in time, because the excessive operation of the bearing can easily lead to a large number of wear problems. Dropping lubricating oil every two to three hours can reduce this problem. friction damage.

2. The slewing bearing is a component with a high reimbursement rate in the whole machine, so when we buy the corresponding machine, we should pay attention to adding a few spare parts when purchasing the bearing, and the material of the spare bearing should also be selected well Otherwise, the bearing will be eliminated soon after use, or the performance of the machine will not be evaporated.

3. The machine should be cleaned every month. At this time, don’t pay attention to dismantling the bearing for cleaning, and clear the large amount of oil or other dirt attached to the bearing, so as to make the whole bearing work effectively. be improved.

In addition, it should be noted that the bolt pre-tightening force should be checked after the slewing ring has been operated for 100 hours, and every 500 hours of operation in the future, sufficient pre-tightening force must be maintained.

In use, it is forbidden to directly wash the slewing ring with water to prevent water from entering the raceway, and strictly prevent hard foreign objects from approaching or entering the tooth meshing area. Check the integrity of the seal frequently. If the seal ring is found to be damaged, it should be replaced in time, and if it is found to fall off, it should be reset in time. In the process of use, grease should be added regularly.

Generally, ball slewing bearings should be refueled every 100 hours of operation, and roller slewing bearings should be refueled every 50 hours. In special working environments, such as high temperature, high humidity, and dust , When the temperature changes greatly and when working continuously, the lubrication cycle should be shortened. When injecting grease, turn the turntable bearing slowly so that the grease is filled evenly. For slewing bearings with internal teeth or external teeth, the debris should be removed frequently and the corresponding grease should be applied.

slewing drive made in china

Slewing drive

Slewing drive is a new type of slewing product, usually also called slewing bearing, which is usually composed of worm, slewing bearing, housing, motor and other components. Because the core component adopts slewing bearing, it can bear axial force, radial force and tipping moment at the same time.

Compared with traditional slewing products, NFB slewing drive is easy to install, easy to maintain, and saves installation space to a greater extent. This product can be widely used in construction machinery and new energy fields such as heavy-duty flatbed trucks, container cranes, truck-mounted cranes, aerial work vehicles, and solar power generation systems for sun patrols.

Mainly divided into the following common rotary drives

Single row four-point contact ball slewing bearing

The single-row four-point contact ball slewing bearing has a row of steel balls as rolling elements, with a single spacer block between the steel balls. The inner and outer rings are integral, and the steel balls are loaded through the filling holes. The steel ball is in contact with the raceway at four points, and can bear axial force, radial force and tipping moment at the same time.

slewing drive Alt.

Single row cross roller slewing bearing

The single-row cross-roller slewing bearing is similar to the four-point contact ball slewing bearing. There is only one row of rolling elements, and the rolling elements are short cylindrical rollers; the axes of adjacent rollers are arranged in a 90° cross; the inner and outer rings have Two raceways, the raceway section is straight. Half of the rollers bear downward axial force, and half bear upward axial force.

Double row reducing ball slewing bearing

The double-row ball reducing ball slewing bearing is composed of upper and lower double-row steel balls, inner and outer rings, spacer blocks and lubrication and sealing devices. In order to make the slewing bearing a complete assembly before it is installed on the main engine, it is necessary to provide several connecting bolts on the circumference to combine the upper and lower ferrules with each other. In order to adjust the clearance of the slewing bearing, the clearance is determined by grinding the end face during assembly.

Three-row roller slewing bearing

The three-row roller slewing bearing is a kind of slewing bearing with high bearing capacity, which is mainly used in the work occasions with large load. It consists of three ferrules, among which there is an adjusting shim between the upper and lower ferrules to adjust the horizontal distribution of the upper and lower rows of rollers for the axial clearance to withstand the axial force from two directions and tipping moment. The radial force is borne by the vertically arranged third row of rollers.

Lightweight flange slewing bearing

The light flange slewing bearing has the same structural form as the ordinary slewing bearing, the difference is that the cross-section of the inner and outer rings of this type of slewing bearing is an ‘L’ shape. Usually the assembly height of this type of slewing bearing is not very high, and the lightweight design makes the light flanged slewing bearing widely used in food machinery, filling machinery and environmental protection machinery.

In addition, our factory also transforms and upgrades such products according to the needs of different users, so that the inner and outer rings are divided into two sections, so users do not need to make extensive repairs to the main engine, they can realize the replacement of slewing bearing spare parts, This new type of slewing bearing is called NFB Huff slewing bearing.

Slewing drive

Slewing drive is a new type of slewing product, usually composed of worm, slewing bearing, housing, motor and other components. Because the core component adopts slewing bearing, it can bear axial force, radial force and tipping moment at the same time.

Trailer turntable

The NFB trailer turntable is developed by our factory according to the current JT/T651-2006 standard and the advanced technology imported from abroad to produce similar products. In the traditional trailer turntable, the raceway part is not quenched, and the raceway is easily worn in actual use, resulting in a shortened service life.

In order to improve the wear resistance of the raceway part, our factory conducts raceway hardening on all products, and the hardness value can reach HRC40~62 or more (related to the material). This makes the products of our factory greatly improved in terms of bearing capacity, wear resistance and service life, which cannot be surpassed by other similar products.

roller bearing slewing ring china

The Installation and Maintenance of Slewing Ring

The structure of slewing bearing

slewing ring Alt.

Preparation

1) Make sure that the model is the same with the contract.

2) Make sure the slewing ring is not damaged during the transportation.

3) Open the package in clean and dry environment.

4) The Bracket should have enough flexility to avoid the distortion of the slewing bearing and influence of its usage.

5)The installation datum plane and bracket installing plane should be clean,grease,burr,paint and other foreign bodys should be wiped off.

Installation

1) The screws in the installing plane should fit with the mounting holes in the slewing ring.

2) Slewing ring ball track quencher soft zone(lies between the exterior mark”S” and the jam.) is in the non-loading zone or non-regularity loading zone.Upper and lower rolling ring “s” soft zone should stagger for 180 degree. The soft zones of crane and excavator machinery should be in the place which forms a 90 degree angle with the arm support direction( the maximum load direction).

3) Put the slewing bearing on the bracket and check the contaction condition between the supporting plane and bracket with feeler gauge, level up with pad mat if clearance appeared, so as to avoid distortion after screwing down, and affect the performance of slewing bearing.

4) Before screwing down, adjust gear side clearance by gear circle radial runout vertex (3 green symbols gears), after screwing down, check gear side clearance in all the gear rings.

5) Install slewing ring with high strength Screws, and choose appropriate strength bolts by stress condition, screw down in 180 degree direction, and check all bolts to ensure that every one in the circle has the same pretightening force, not spring washer but hardening plain steel washer should be choosed in installation, screw down bolts in turn by the picture below:

6) After installation, you should wife off the dust and dunghill in the slewing ring and paint some antirust paiting,also paint some lubricate grease in raceway and gear.

Operation,Maintenance and Lubrication

1) Before the slewing bearings leave factory ,some No.2 EP grease (GB7324-1994) should be in slewing bearing raceway, change it into new lubricate grease according to your different working conditions.

Add grease regularly in slewing bearing raceway. Ball slewing bearing is lubricated every 100 hours, roller slewing bearing is lubricated every 50 hours, shorten the lubricate period in specially working condition, for example: in torrid zone, with high humidity, more dust, fast changing temperature and working continuously. Add enough grease before and after the the machine’s long-term stop. Fill the raceway with grease till it is seeping from the seals.turn slewing ring slowly when you add grease to make the grease equally filling.

2) Usually wipe off the foreign bodys and spread grease.

3) Check the pretightening force of the blot after the slewing bearing running first 100 hours, then make sure enough pretightening force every another 500 hours.

4) Give your attention to the running slewing bearing, you should stop it to check when noises, impulsion, abrupt accretion power appeared, and dismantle it to check when necessary.

5) Its better to protect the slewing bearings from dust, rain,water and high tempreture in operation, and defend gear engagement zone against hard objects.

6) Check the seal usually, change it when it is damaged,reset it when it is breaking off.

Commonly used lubricants have been list in the following table,Often lubricate the reverse with gear grease

Bearing Structure	Working Condition		Lubricated Parts	Lubricant
Bearing Structure	Working Condition		Lubricated Parts	Product	Quality Marker	Standard
Plastic insulation rubber ring seal	Low and normal temperature,moist -20℃ + 60℃		Ball Track	Extreme pressure lithium lubricating grease	No.1 No. 2	GB7323-1994
Plastic insulation rubber ring seal	Low and normal temperature,moist -20℃ + 60℃		Geared wheel	Black Lead Radical Lubrication	ZG-S	SH/T0369-1992
Metal Insulation Iabyrinth packing	High Temperature, moist	40°C ～120°C	Ball Track	Extreme pressure lithium lubricating grease	No.1 No.2	GB7323-1994
			Ball Track	M0S2 Compound calcium radical lubricating grease	No.2
			Geared wheel	No.4 high temperature lubricating grease	No.4	SH0376-1992
		80°～180°C	Ball Track	M0S2 Compound calcium radical lubricating grease	No.2
		80°～180°C	Geared wheel	No.4 high temperature lubricating grease	No.4	SH0376-1992
	Normal temperature, resistance to sea～60°C		Ball Track	No.2 Compound aluminum radical lubricating grease	No.2
	Normal temperature, resistance to sea～60°C		Geared wheel	No.4 aluminum radical lubricating grease	No.4	SH0378-1992

Preservation

The slewing bearing has been sealed with oil before it leaves the factory. The packed slewing ring at optimal conditions can be stored for 6 months. Idle ball tracks need lubricating every 2 months.(please refer to “Maintance and Lubricating”).Idle slewing bearing needs oil sealed packaging every 6 months.

Oil Sealed Packaging:

1) Take out the slewing ring from the wood box.

2) When removing the wrapping, do not rip the sealing tape, remove the wrapping from the outside to the inside.

3) After taking the slewing bearing into pieces, infuse the ball track with lubricating grease.First deoil the surface and then do oil sealed packaging.

4) When deoiling, do not infuse solvent containing chlorie into sealing band and the ball track.

5) After deoiling, clean down the out surface, plaster the preservative oil and grease(F20-1) or industrial petroleum jelly(SY1607-77)evenly.

6) Then ,pack it as it was primarily done.Encase it again in the wood box.It is better to batter down a asphalt felt in the box to protect against moisture and rain.If there is no box to store the bearing, after oil sealed packaging, store it in folds.

china without gear bearing(no gear)

What is the working temperature of the gear bearing?

The gear bearing is a very important part in the machine. Basically, every machine needs this part. Because this part is relatively fragile, it can also be regarded as a kind of consumables. You need to buy it frequently to keep the machine in good condition. normal operation.

The gear bearing can work normally at -300C～+700C. If the user needs to adapt to the lower or higher temperature gear bearing, our company can make special design. If the gear bearing is used in particularly harsh environments, such as marine climate, dust or abrasive particles, sand, cement, coal powder, etc.

Special sealing rings, protective devices, and suitable oil passages should be selected. Therefore, in order to make your support function normally, it is hoped to do a good job in daily maintenance and maintenance.

The tooth surface of the gear bearing should be cleaned and changed every 8-10 working days, and foreign matter should not be mixed.

Features of gear bearing materials

The gear bearing is mainly composed of ferrules, rolling elements, cages, sealing rings, etc. Since different parts have special functions in practical applications, there are different considerations in the design and selection of materials.

In general, the rolling elements of the slewing ring are made of carbon-chromium bearing steel that is hardened as a whole. The slewing bearing ring is made of surface hardened steel. When the user has no special requirements, it is generally made of 50Mn steel.

However, sometimes in order to meet the needs of the host in some special applications, other grades of surface can also be selected according to the specific use conditions provided by the user. Hardened steel, such as 42CrMo, 5CrMnMo, etc.

For small and medium gear bearing forgings, round or square bars are used as blanks. The grain structure and mechanical properties of the bar are uniform and good, the shape and size are accurate, and the surface quality is good, which is convenient for mass production.

As long as the heating temperature and deformation conditions are reasonably controlled, forgings with excellent performance can be forged without large forging deformation. Ingots are only used for large forgings. The ingot is an as-cast structure with large columnar crystals and a loose center.

Therefore, through large plastic deformation, the columnar crystals must be broken into fine grains, and the loose compaction can be obtained in order to obtain excellent metal structure and mechanical properties.

The cages for Slewing Bearing have integral, segmented, spacer block and other structural forms. The integral and segmented cages are made of 20-gauge steel or ZL102 cast aluminum alloy. The spacer block type is made of polyamide 1010 resin, ZL102 cast aluminum alloy, etc. With the continuous development of the material industry, nylon GRPA66.25 has also been popularized and applied in the design of segmented cages.

The material of the gear bearing seal is made of oil-resistant nitrile rubber. The codes of the ferrule material and the supply status of the blank are as specified in the table. In the table, “T” means that the blank of the ring is supplied in a quenched and tempered state, and “Z” means that the blank of the ring is supplied in a normalized state.

gear bearing Alt.

2.How is gear bearing fatigue life affected? What are the influencing factors?

1. The effect of nitrides on gear bearing fatigue life

It has been pointed out that when nitrogen is added to the steel, the volume fraction of nitrides decreases. This is because the average size of the inclusions in the steel decreases. Due to the limitation of technology, there are still a considerable number of small-volume inclusion particles that are not counted.

It is precisely the existence of these tiny nitride particles that has a direct impact on the fatigue life of bearing steel. Ti is one of the strongest elements to form nitrides. It has a small specific gravity and is easy to float. There will also be a part of Ti left in the steel to form multi-angular inclusions. Such inclusions are likely to cause local stress concentration and fatigue cracks, so it is necessary to control the occurrence of such inclusions.

The test results show that the oxygen content in the steel is reduced to below 20ppm, the nitrogen content is increased, the size, type and distribution of non-metallic inclusions are improved, and the stable inclusions are significantly reduced.

Although the nitride particles in the steel increase, the particles are very small and are distributed in a dispersed state at the grain boundary or within the grain, which becomes a favorable factor, so that the strength and toughness of the bearing steel are well matched, and the hardness and strength of the steel are greatly increased. , especially the improvement effect on fatigue life exists objectively.

2. The influence of oxides on bearing fatigue life

The oxygen content in the steel is an important factor affecting the material. The lower the oxygen content, the higher the purity and the longer the corresponding rated life. There is a close relationship between the oxygen content in steel and oxides.

During the solidification process of molten steel, the dissolved oxygen of aluminum, calcium, silicon and other elements forms oxides. The oxide inclusion content is a function of oxygen. As the oxygen content decreases, the oxide inclusions will decrease; the nitrogen content is the same as the oxygen content, and also has a functional relationship with the nitride, but because the oxide is more dispersed in the steel, it plays the same role as the carbide. , so it has no destructive effect on the fatigue life of steel.

The existence of oxides destroys the continuity of the metal matrix, and because the expansion coefficient of oxides is smaller than the expansion coefficient of the bearing steel matrix, when subjected to alternating stress, it is easy to generate stress concentration and become the origin of metal fatigue. Most of the stress concentration occurs between oxides, point inclusions and the matrix. When the stress reaches a large enough value, cracks will occur, which will rapidly expand and destroy. The lower the plasticity of the inclusions and the sharper the shape, the greater the stress concentration.

3. The effect of sulfide on fatigue life

Almost all of the sulfur content in steel exists in the form of sulfides. When the sulfur content in the steel increases, the sulfide in the steel increases accordingly, but because the sulfide can be well surrounded by the oxide, the influence of the oxide on the fatigue life is reduced, so the number of inclusions has no effect on the fatigue life. , which is related to the nature, size and distribution of the inclusions.

It is not necessarily that the more inclusions, the lower the fatigue life, and other influencing factors must be considered comprehensively. In bearing steel, sulfides are dispersed and distributed in a fine shape, and are mixed with oxide inclusions, which are difficult to identify even by metallographic methods.

Experiments have confirmed that, on the basis of the original process, increasing the amount of Al has a positive effect on reducing oxides and sulfides. This is because Ca has a fairly strong desulfurization ability. Inclusions have little effect on the strength, but are more harmful to the toughness of the steel, and the degree of damage depends on the strength of the steel.

high speed ball slewing ring bearing in stock

1.The working principle and working mode of the slewing ring bearing

Slewing ring bearings are widely used in machinery, such as excavators, disintegrators, stackers and reclaimers, graders, road rollers, and roadheaders. Not only that, but also in new energy equipment, amusement equipment, metallurgical equipment, etc. It also has its application in China, so what is the working principle and working method of the slewing bearing?

First, the working principle of the slewing ring bearing
The working principle of the slewing ring bearing is to move the object from sliding to rolling to reduce frictional resistance. It mainly relies on lubrication and friction to achieve the purpose of operation. Internally, it relies on the mutual friction of balls and steel rings.

The friction between the bearing and other parts runs, rubs against each other, and drives the object to operate. Although it relies on friction to operate, lubrication is also indispensable. If it is used for a long time and the friction is too large, it will also affect the application of parts. Therefore, after using this kind of bearing for a period of time, it should be maintained in time. , brush some lubricating oil.

2. How the slewing ring bearing works

1. Point contact scrolling
The working principle of point contact rolling is mainly used for four-point contact ball slewing bearing and crossed roller slewing bearing. This working principle has higher requirements on the quality of steel balls for the combined bearing of point contact radial and axial forces, and the angle of the track should be uniform.

2. Rolling and sliding combined rolling type
The rolling-slip combined rolling working principle is mainly used for the ball-column combined slewing ring bearing. This principle has the advantages of small eccentricity and long service life, and has the advantages of the double structure of the roller and the ball.

3. Surface contact rolling and sliding combination
The working principle of surface contact rolling and sliding combination is mainly used for turntable bearings. Now the new type of slewing bearing has a compact structure and high precision, so it is suitable to use the surface contact rolling and sliding combination.

4. Surface contact rolling combination
The surface contact rolling combined working principle is mainly used for three-row roller slewing bearing, its advantage is that the contact surface is large, the bearing force is uniform and the rolling is flexible.

slewing ring bearing Alt.

2.Installation method of non-standard slewing ring bearings

1. Cleaning before installation

If there are bumps, rust layers, wear debris, sand, dust and mud on the bearing assembly surface and the surface of the parts that match it, firstly, the bearing is difficult to install, resulting in incorrect assembly position; secondly, these attachments form abrasive, easy to The working surface of the non-standard bearing will be rubbed and the assembly quality will be affected.

Therefore, the surface of the journal, the surface of the bearing housing shell, the end face of the shoulder, and the mating surface of the connecting parts such as bushings, washers, ends, etc., should be carefully inspected before installation. If there is a rust layer, it can be removed with a fine file, polished with a fine emery cloth, and the attachments on the bearing assembly surface and its connecting parts should also be removed.

2. Install according to the installation instructions

For slewing ring bearings with separable inner and outer rings, do not exchange the outer rings with each other to avoid affecting the contact quality. For non-standard bearings, do not arbitrarily remove the rolling elements in the bearing and mix them, so as to avoid the installation position disorder affecting the accuracy.

When installing the bearing, in order to facilitate the viewing of the bearing code and not to make mistakes, the bearing ring should be placed and installed with the typing surface facing outward.

3. Heating installation

For medium and large bearings with large interference, in order to facilitate installation, they must be heated before installation; for tight fit light metal bearing housing holes (such as aluminum bearing housings), due to the low hardness, in order to prevent the bearing outer ring from being pressed into If the surface of the housing hole of the bearing housing is scratched or scratched, it should also be heated and installed.

The heating method is generally to put the bearing or separable bearing ring into the oil tank filled with clean oil, so that the oil submerges the non-standard bearing and heats it evenly. When the temperature reaches 80-90 ℃, take it out, wipe it, and install it while it is still hot.

The fuel tank can be made of 2-3mm thick iron plate, a porous iron plate is added at a height of 50-70mm from the bottom of the tank, and the bearing is placed on the porous iron plate for heating. The purpose is to avoid the impurities deposited in the oil from entering the bearing.

However, for bearings with dust caps or sealing rings on both sides, since lubricants have been added during manufacture, they cannot be heated in the early stage of installation.

china slewing ring manufacturers

1.What is a slewing ring in crane?

Crane Slewing Ring

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 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 Ring

In lifting equipment like cranes, slew rings create a joint between the undercarriage and the upper structure of the machine. These 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 rings 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.

Why Is Crane Slewing Ring Maintenance Important?

Slew rings support many of a crane’s functions. If any one of these components fails, the equipment and its operators are at risk. The majority of slew ring failures revolve around overloading, incorrect installation and surface lubrication issues. Among the three problems, lubrication is the most common maintenance mistake.

Since slewing rings are responsible for various movements and weight balancing, they require high-pressure grease to prevent surface roughening and cracks caused by friction and debris. With enough wear from these factors, slewing rings can spall, leading to complete machine failure.

Regular lubrication is the solution to early wear in a crane slew ring. During these maintenance checks, individuals should also perform torque checks on bolts to ensure the system is prepared to operate at maximum capacity levels.

Condition monitoring can also help teams identify system failures as they happen. This type of maintenance check will often require a grease examination to determine the lubricant’s quality and effectiveness in preventing wear.

slewing ring Alt.

Work With LYMC to Maintain Your Crane Slewing Ring

LYMC carries a selection of slewing rings for your project applications. With the E-Series slewing ring, engineers can meet heavy-load requirements in crane designs. The helical teeth configuration allows for pinion meshing and worm gear meshing in slew drives.

Our team works with different applications engineers to assist in selecting the appropriate product for their cranes. Through understanding the final crane load requirements, safety factors and material treatments, we are able to provide standard and custom-made solutions across multiple models.

We use durable materials and advanced slew ring designs to deliver cost-effective solutions to equipment engineers. We act as a technical consultant for your team to find the right slewing ring configuration for your heavy equipment project.

Our slewing rings are an excellent addition to a machine in the early design process. Our slew rings for cranes are also a valuable replacement if your existing ring starts to spall. With the proper lubrication and maintenance, our slew rings offer longevity and heavy-load performance.

2.Slewing ring Assembly

Slewing ring is a kind of large bearing with special structure, which can bear the overall load such as axial load, radial load and overturning load.

It combines support, rotation, transmission, fixation, sealing, anticorrosion and other functions into one unit.

Inner and outer rings

Generally, slewing rings consist of two rings, each ring contains a precision raceway that is Induction quenched on the surface to a specified depth.

Each ring is forged from 50Mn or 42CrMo.

Different internal structures can be selected according to load capacity, including Single-row ball series、Double-row ball series、Double-line ball series 、Roller and ball combination series、Three-row roller series.

Rolling body

The precision rolling body can promote the relative rotation between the inner and outer rings.

Steel balls or rollers are often used as rolling body.

Isolation block

Spacer blocks usually made of nylon which are usually used to separate balls or rollers,

this prevent them from rubbing against each other directly .

Under special conditions , steel and copper holder can be used.

Mounting holes

The mounting holes are usually spaced along the surface of the inner and outer rings which along a uniform bolt circumference and equally spaced apart.

These holes can be through holes, threaded holes, blind holes, countersunk holes, etc. Sometimes, need to customize bolts with spacing requirements to meet a specific application.

Sealing strip

There are sealing strips on each side of the slewing ring.

Its main function is to retain grease and prevent certain contaminants (such as dust and debris) from entering.

The seal is usually made of Nitrile Butadiene Rubber.

Plug

Drill a hole in the position of the non-gear ring or the outer ring of the non-gear bearing, and install the ball or roller into the slewing ring raceway.

The hole is plugged and fixed with a taper pin.

The unhardened clearance will be engraved with the word “S”, Namely: soft belt.

gear

Slewing bearings are available in toothless or internal or external type.

Custom gear configurations are also available.

Greaser

The slewing bearing include at least one grease fitting

The number may increase with the diameter of the slewing rings.

For gear bearings, the grease fitting is located on the inner or outer circle of the toothless ring.

The sign

The part number and serial number are engraved next to the plug of the slewing ring.

in stock cross roller slewing ring

1.Causes and preventive measures of shaking during operation of slewing ring

1. The reason for the jitter of the slewing bearing during operation

1. Internal machining accuracy of slewing bearing

The machining accuracy of the steel ball inside the slewing ring and the machining accuracy of the inner raceway are not high, or there are quality defects and the lack of lubricating oil in the raceway. When the slewing bearing is defective, sometimes the frequency of failure can be reduced by replacing the steel ball.

2. The machining of gears is not precise enough

The gear accuracy grade of the slewing ring should be between 7 and 11, which determines the stability of the slewing ring transmission, the uniformity of the load distribution and the transmission accuracy. The higher the gear precision, the denser the contact spots on the meshing tooth surface, so that the noise value is reduced and the operation stability is improved.

3. Welding defects of upper and lower supports

If the welding quality is not up to standard, it is necessary to repair and repair the weld defects. During repair welding, it will not only generate new welding stress, but also have a great impact on the flatness of the machined mounting surface.

At the same time, the current generated by welding will also cause certain damage to the internal rolling elements and raceways when passing through the slewing bearing. damage. In addition, if the assembly error generated in the manufacturing and assembly, the threading of the pin shaft and the pre-tightening of the bolts in the field installation do not meet the specified requirements, abnormal noise or vibration will also occur.

4. Quality problems of gears and starting motors

Due to the long working time of the gear under load, small pieces of metal or strip-shaped metal iron filings will appear near the pitch line of the tooth surface, resulting in pitting or gnawing.

The pitting corrosion of the tooth surface continues to expand with the increase of working time, so that the meshing tooth profile is damaged, the noise and impact during rotation increase, and the metal particles impacted repeatedly accelerate the wear of the tooth surface, forming a vicious circle.

In addition, the manufacturing and assembly of the starter motor in the slewing mechanism has its own defects, which produce shock jitter, and the meshing process between the drive wheel and the support is unstable, which also increases the frequency of jitter and the decibel of abnormal noise.

slewing ring Alt.

2. Preventive measures for slewing bearing jitter

1. Installation and operation

High-strength bolts should be used to install the slewing ring, and the bolts and nuts should meet the requirements of GB3098.1 and GB3098.2 standards. Spring washers are prohibited. Before the installation bolts are tightened, the meshing adjustment (backlash) of the large and small gears must be carried out, and the meshing of the slewing bearing and the pinion should be ensured to meet the requirements.

Tighten the mounting bolts at 180°, the mounting plane must be clean and flat, and there must be no burrs, iron filings and other debris, and the plane must meet the following requirements: the slewing bearing often has broken teeth during operation, so it is also The influence of wind on the slewing bearing should be taken into account.

If the jib cannot rotate freely with the wind after the operation exceeds the specified wind force or stops the operation, it may damage the gear meshing with the bearing or the slewing bearing, and a serious safety accident will occur. Therefore, detailed inspection should be done during installation and operation.

2. Fastening bolts

The connecting bolts of the slewing bearing and the upper and lower supports are subjected to axial pulsating load in addition to the pre-tightening force, which will cause the bolt to be elongated or the connecting surface to deform, making the bolt loose.

If the loosening pre-tightening force of the bolt connection fails to meet the requirements, the axial clearance will increase, the rolling elements will be rotated by a large overturning moment, and the edge of the raceway will be subjected to huge contact stress, which will cause the edge of the raceway to be damaged.

Therefore, it is necessary to regularly check the tightening of the slewing bearing bolts to make them reach the specified pre-tightening force, which is generally 400-500 N.m.

3. Internal lubrication of slewing ring

In daily use, each component should be lubricated according to the lubricant, lubrication method and lubrication cycle regulations in time and on time according to the instruction manual. The corresponding ball slewing bearing is generally refilled every 100 hours of operation, and the roller slewing bearing is filled every 50 hours.

For special working environments with a lot of dust, high humidity and high temperature difference, the lubrication cycle should be shortened. The raceway must be filled with each lubrication until the lubricating oil seeps out, and the slewing bearing needs to be slowly rotated to make the grease evenly filled while filling.

By adding lubricating oil for maintenance, the friction between the gear pairs can be reduced, the wear speed of the gear ring can be slowed down, and the formed oil film can also act as a shock absorber to eliminate part of the vibration energy generated during operation. In addition, the lubricating oil film can also lubricate and clean each friction surface well, prevent rust, and eliminate the influence of iron filings on the friction surface. Thereby reducing the friction noise of the operation and increasing the service life of the bearing.

high quality slew bearing factory

1.Cold treatment process and function of slew bearing

First, the role of cold treatment

Precision slew bearings have high requirements for dimensional stability; after quenching of the slew bearing (especially staged quenching), the internal structure still retains a lot of retained austenite. This retained austenite is an unstable structure.

During the process, changes will continue to occur, thereby changing the accuracy of the bearing. For this reason, a cold treatment process is used, which can reduce the retained austenite in the structure and slightly increase the hardness of the part.

2. Cold treatment process and requirements

1. Stay at room temperature after quenching: After quenching, be sure to cool the inside and outside of the ferrule evenly to room temperature before cold treatment, otherwise it is easy to crack, and immediately after cooling to room temperature (generally no more than 30min), otherwise it will stop the austenite to the horse. The transformation of the body.

2. Cold treatment temperature: The temperature of cold treatment is mainly based on the martensite transformation termination temperature Mf of the steel, and the influence of cold treatment on mechanical properties and manufacturability should also be considered.

For GCr15 steel, use -70℃ for cold treatment; when there are restrictions on ferrules or equipment with low precision requirements, the cold treatment temperature can be selected as -40～-70℃; for super precision bearings, the temperature can be between -70℃～-80℃ Cold treatment in between. Subcooled temperatures affect slew bearing impact fatigue and contact life.

3. Cold treatment and heat preservation: Although the transformation of a large amount of martensite is completed when it is cooled to a certain temperature, in order to make the surface and core of a batch of ferrules reach the cold treatment temperature evenly, a certain heat preservation time is required, generally 1 to 1.5 h.

4. Tempering after cold treatment: The ferrule is placed in the air after cold treatment, and its temperature is slowly raised to room temperature and then tempered in time. The temperature rise cannot be too fast, otherwise it is easy to crack; if the tempering is timely, otherwise the large residual stress inside the ferrule will cause the ferrule to crack, generally not more than 2h.

slew bearing Alt.

2.What are the factors that affect the fatigue life of slew bearing steel?

1. The effect of nitrides on fatigue life

Some scholars have pointed out that when nitrogen is added to the steel, the volume fraction of nitrides decreases. This is due to the reduction in the average size of the inclusions in the steel. Limited by technology, there are still a considerable number of inclusion particles smaller than 0.2 in. counted.

It is precisely the existence of these tiny nitride particles that has a direct impact on the fatigue life of slew bearing steel. Ti is one of the elements that form nitrides. It has a small specific gravity and is easy to float. There will also be a part of Ti left in the steel to form multi-angular inclusions.

Such inclusions are likely to cause local stress concentration and fatigue cracks, so it is necessary to control the occurrence of such inclusions.

2. The effect of oxides on fatigue life

The oxygen content in steel is an important factor affecting the material. The lower the oxygen content, the higher the purity and the longer the corresponding rated life. The oxygen content in steel is closely related to oxides. During the solidification process of molten steel, the dissolved oxygen of aluminum, calcium, silicon and other elements forms oxides.

The oxide inclusion content is a function of oxygen. As the oxygen content decreases, the oxide inclusions will decrease; the nitrogen content is the same as the oxygen content, and also has a functional relationship with the nitride, but because the oxide is more dispersed in the steel, it acts as a fulcrum with the same function as the carbide. , so it has no destructive effect on the fatigue life of steel.

Due to the existence of oxides, steel destroys the continuity of the metal matrix, and because the expansion coefficient of oxides is smaller than the expansion coefficient of the slew bearing steel matrix, when subjected to alternating stress, it is easy to generate stress concentration and become the origin of metal fatigue.

Most of the stress concentration occurs between oxides, point inclusions and the matrix. When the stress reaches a sufficient level, cracks will occur, which will rapidly expand and destroy. The lower the plasticity of the inclusions and the sharper the shape, the greater the stress concentration.

3. The effect of sulfide on fatigue life

Almost all of the sulfur content in steel exists in the form of sulfides. When the sulfur content in the steel increases, the sulfide in the steel increases accordingly, but because the sulfide can be well surrounded by the oxide, the influence of the oxide on the fatigue life is reduced, so the number of inclusions has no effect on the fatigue life.

Certainly, it is related to the nature, size and distribution of inclusions. The more inclusions, the lower the fatigue life must be, and other influencing factors must be considered comprehensively.

In bearing steel, sulfides are dispersed and distributed in a fine shape, and are mixed with oxide inclusions, which are difficult to identify even by metallographic methods.

Experiments have confirmed that on the basis of the original process, increasing the amount of Al has a positive effect on reducing oxides and sulfides.

This is because Ca has a fairly strong desulfurization ability. Inclusions have little effect on the strength, but are more harmful to the toughness of the steel, and the degree of damage depends on the strength of the steel.

in stock cross roller slewing ring

1.Cross Roller Slewing Ring

Cross roller Slewing rings and turntable bearings can accommodate axial, radial and moment loads. They are not housed or mounted on a shaft, but are instead mounted directly to a seating surface. The inner and outer rings are supplied with mounting holes and often include internal or external gears.

There are several basic types of products. Single-row slewing rings and turntable bearings feature a single row of balls, a standard bearing raceway, and four points of contact between the balls and raceway. Double-row products feature two rows of ball bearings, two raceways, and eight points of contacts for each ball.

Slewing rings and turntable rings with three independent rows of rollers are also available. Cross rollers have a single row of rollers with the axes of alternating, adjacent rollers at right angles to one another. Cross roller Slewing ring and turntable bearings with a single row of balls and a single row of rollers are designed for small radial runout and high thrust roads.

Typically, inserted raceways are made of wire and use either a ball or roller as the contact element.

Cross roller Slewing ring and turntable bearings vary in terms of physical dimensions and operating specifications. Bore size, outside diameter and overall width are the most important physical dimensions to consider. Metric bores are measured in millimeters (mm) and specified according to a standard numbering system that ranges from 00 (10 mm) to 20 (100 mm).

Bore sizes 00, 01, 02, and 03 are 10 mm, 12 mm, 15 mm, and 17 mm, respectively. For bore sizes 04 and up, multiplying the bore size by 5 yields the bore diameter. Slewing rings and turntable bearings that are measured in inches (in) or fractions of an inch are also available.

For flanged bearings, the outside diameter excludes the size of the flange. Overall width includes the size of the locking collar, if present. In terms of operating specifications, the most important measurements to consider are static axial or thrust load, static radial load, and moment load. Typically, these specifications are measured in pounds (lbs) or feet-pounds (ft-lbs).

Single-row four point contact ball slewing bearing is generally composed of two rings, compact, light weight, and circular raceway ball four point contact, can withstand the axial force, radial force and overturning moment, according to the customer You can use different occasions were selected ring, install and easy to use with an internal or external gear teeth.

Rotary conveyors, welding operation machine, small cranes and excavators and other construction machinery can be selected

2.What is a crossed roller bearing

The single row crossed roller bearing is composed of two seat rings, which design in compact structure and light weight; this single row crossed roller type slewing bearing has the steel roller for the rolling element, not for the steel ball.

As the rollers are 1:1cross arranged, it is suitable for high precision mounting and capable to bear axial force, resultant moment and considerable large radial force. The axial and radial clearance is smaller than single row ball slewing bearing. The rotating is not so flexible as the one row ball bearings, usually it use for some higher precision applications.

Our single row crossed roller slewing bearing ring’s axial and radial clearance’s precision is high.

Single row crossed roller ring bearings are mainly made of 50 Mn, 42CrMo and C45.

The single row crossed roller bearing has been widely used in many applications:

cross roller slewing ring Alt.

1. Military product

2. Automation machinery, Robots

3. Medical equipment

4. Radar equipment

5. Tank

6. Grinding machine and drilling machine.

Cross roller slewing bearings are primarily used when a single row ball slewing bearing does not meet operating performance requirements for high stiffness, high precision, as well as rotation torque.

The clearance is usually smaller than single row ball slewing bearing, from 0-0.03mm (preload). Because the rollers are 1:1 cross arranged, this compact structure is capable to bear axial force, tilting moment and much more radial force.

china wholesale slewing gear factory

1.Are bearing inner rings interchangeable? Can old and new slewing gear be mixed?

Are bearing inner rings interchangeable? When replacing old slewing gears, some manufacturers find that the reasons for the damage and failure of bearing accessories are different, and they want to know if the inner ring of the bearing is damaged, can the inner ring accessories of another bearing be replaced for combined use, and want to extend the bearing life in this way.

The frequency of use reduces the cost of replacing the bearing, but it is also worried that it will affect the service life of the bearing.

1. Can the inner ring of the slewing gear be interchanged?

The inner ring of the slewing gear is interchangeable. In fact, as long as it is the same type of slewing gear or the bearing inner ring with the same bearing suffix, it can be exchanged. In this case, do not replace the bearing’s outer ring type suffix.

The two types of slewing gears are different, so they cannot be replaced. If If it is found that the inner ring of the same model is mixed, it will not affect the quality and life of the bearing after assembly.

Some bearings fail due to various reasons, and some parts of the bearing are in good condition. At this time, it is possible to remove the outer ring of the bearing for use. However, some slewing gears themselves have bearings without an outer ring, and the inner ring of the bearing cannot be taken out independently. ,

At this time, it is recommended that customers do not blindly remove the outer ring to use, so as to waste the cost of an outer ring and increase itself. Replacement should be tried according to the specific conditions of the bearing.

2. Can old and new slewing gear be mixed?

For worrying about whether the operation of using old slewing gear parts to assemble new bearing parts will affect the service life or performance of the bearing, in fact, this also needs to be analyzed in detail. If there are no problems such as wear and deformation of the parts, the new and old bearing parts are suitable for use.

In the case of matching, it can be mixed. However, if the clearances of some accessories are different or do not fit, it is not recommended to mix them, and there may be poor operation or other wear and noise conditions that affect the normal operation of the slewing gear.

However, if the spare parts are of the same type, and there is no wear deformation or other faults after inspection, then the old and new bearings can be mixed.

slewing gear Alt.

2.What are the factors that affect the fatigue life of bearing steel?

Factors Affecting Fatigue Life of Bearing Steel

1. The effect of nitrides on fatigue life

Some scholars have pointed out that when nitrogen is added to the steel, the volume fraction of nitrides decreases. This is due to the reduction in the average size of the inclusions in the steel. Limited by technology, there are still a considerable number of inclusion particles smaller than 0.2 in. counted.

It is precisely the existence of these tiny nitride particles that has a direct impact on the fatigue life of slewing gear steel. Ti is one of the elements that form nitrides. It has a small specific gravity and is easy to float. There will also be a part of Ti left in the steel to form multi-angular inclusions.

Such inclusions are likely to cause local stress concentration and fatigue cracks, so it is necessary to control the occurrence of such inclusions.

2. The effect of oxides on fatigue life

The oxygen content in the steel is an important factor affecting the material. The lower the oxygen content, the higher the purity and the longer the corresponding rated life. There is a close relationship between the oxygen content in steel and oxides.

During the solidification process of molten steel, the dissolved oxygen of aluminum, calcium, silicon and other elements forms oxides. The oxide inclusion content is a function of oxygen.

As the oxygen content decreases, the oxide inclusions will decrease; the nitrogen content is the same as the oxygen content, and also has a functional relationship with the nitride, but because the oxide is more dispersed in the steel, it plays the same role as the carbide. , so it has no destructive effect on the fatigue life of steel.

Due to the existence of oxides, steel destroys the continuity of the metal matrix, and because the expansion coefficient of oxides is smaller than the expansion coefficient of the bearing steel matrix, when subjected to alternating stress, it is easy to generate stress concentration and become the origin of metal fatigue.

Most of the stress concentration occurs between oxides, point inclusions and the matrix. When the stress reaches a large enough value, cracks will occur, which will rapidly expand and destroy. The lower the plasticity of the inclusions and the sharper the shape, the greater the stress concentration.

3. The effect of sulfide on fatigue life

Almost all of the sulfur content in steel exists in the form of sulfides. When the sulfur content in the steel increases, the sulfide in the steel increases accordingly, but because the sulfide can be well surrounded by the oxide, the influence of the oxide on the fatigue life is reduced, so the number of inclusions has no effect on the fatigue life.

Certainly, it is related to the nature, size and distribution of inclusions. The more inclusions, the lower the fatigue life must be, and other influencing factors must be considered comprehensively. In bearing steel, sulfides are dispersed and distributed in a fine shape, and are mixed with oxide inclusions, which are difficult to identify even by metallographic methods.

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