Research and analysis on the usability of slewing bearings

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The slewing bearing is a large bearing that can bear large axial load, radial load and overturning moment at the same time. Turntable bearings are generally equipped with mounting holes, internal or external gears, lubricating oil holes and sealing devices, which can make the mainframe structure compact, reliable guidance, and convenient maintenance. It is widely used in large slewing devices such as lifting and transporting machinery, mining machines, construction machinery, port machinery, wind power generation, medical equipment, radar and missile launchers. Today, I will talk to you about the usability of slewing bearings.

Compared with other mechanical parts, slewing bearings have a very unique feature, that is, their life span is very discrete. Due to this characteristic of slewing bearings, there will be such a situation in actual use: some bearings have greatly exceeded their design life and can still work normally, while some bearings are far from reaching their design life. Therefore, if the bearing is regularly repaired according to the design life: on the one hand, it will cause the slewing bearing that has exceeded the design life but is still working to be removed for scrapping, resulting in waste; on the other hand, the bearing that fails to reach the design life and fails It was not discovered in time, and was dismantled and scrapped until regular maintenance. This reduced the accuracy of the machine during the period after the bearing failed and before it was scrapped, or there was a serious failure before the repair time, which caused the entire machine to be paralyzed.

Early detection and fault diagnosis of slewing bearing working status and faults have important practical significance for the safe and stable operation of equipment.

In actual research, we can make preliminary performance status judgments on some phenomena based on experience, such as checking the size and sound quality of the rolling sound of a rotating turntable bearing. Even if there is slight damage such as peeling, abnormal noise and abnormal noise will be emitted. Regular tone. Through the analysis of these sounds, it can be used as one of the basis for judging whether the bearing is running well.

In addition, the judgment of some performance conditions requires the use of related testing tools. The vibration of the slewing bearing is very sensitive to the damage of the bearing, such as peeling, indentation, rust, cracks, wear, etc., will be reflected in the vibration measurement of the slewing bearing. Therefore, the vibration can be measured by using a special slewing bearing vibration measuring device (such as a frequency analyzer, etc.). Through the analysis of the vibration frequency, further infer the abnormal situation. However, since the measured values are different due to the use conditions of the slewing bearing or the installation position of the sensor, it is necessary to analyze and compare the measured values of each machine in advance to determine the judgment standard.

Effective utilization and adjustment of slewing bearing clearance

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Slewing bearings are mainly used in lifting, construction machinery and other large-scale construction machinery and equipment. They mainly bear axial force and overturning moment. However, in many cases, overturning moment is the main load of the bearing. Under the action of the overturning moment, the angular deformation of the bearing will greatly affect the stiffness and working accuracy of the entire machine. Therefore, it is necessary to analyze the relationship between the moment load bearing and the deformation of the turntable bearing.
The function and requirement of bearing clearance is to ensure that the bearing can run flexibly and without hindrance, but it is also required to ensure that the bearing runs smoothly. According to the state of the bearing, the clearance can be divided into three general existence states: original clearance, installation clearance and working clearance.

The clearance (called the working clearance) during operation has an impact on the performance of the slewing bearing and slewing ring, as well as the precision rolling fatigue life, temperature rise, noise, and vibration. When selecting the bearing clearance, it is generally appropriate to make the working clearance zero or slightly positive. Because it is actually installed in the machine, the slewing bearing has to bear a certain load to rotate, and there is also the amount of elastic deformation caused by the bearing and the load. And, considering the factors of thermal expansion (load), enough clearance is reserved, and proper installation clearance will help the normal operation of the rolling bearing. If the clearance is too small, the temperature of the rolling bearing will rise, and it will not work properly, and the rolling elements will be stuck; if the clearance is too large, the equipment will vibrate and the rolling bearing will be noisy.


The choice of the best working clearance is determined by the application conditions (load, speed, design parameters) and the expected working conditions (lifetime, rigidity, low heat generation, ease of maintenance, etc.). However, in most applications, we cannot directly adjust the working clearance, which requires us to calculate the corresponding clearance value after installation based on the analysis and experience of the application.

1. The selection principle of bearing clearance

①With a tighter fit, the temperature difference between the inner and outer rings is large, the friction torque needs to be reduced, and the deep groove ball bearing bears a larger axial

In the case of load or need to improve the self-aligning performance, a large clearance group should be adopted.

②When the rotation accuracy is high or the axial displacement needs to be strictly limited, a small clearance group should be used.

2. Factors related to clearance: the fit of the inner ring of the bearing and the shaft;

the fit of the outer ring of the bearing and the housing hole; the influence of temperature.

3. How to adjust the axial clearance

①Use the nut installed on the bearing housing to push the gland pressed on the outer ring of the bearing for adjustment.

②Adjust the thickness of the gasket between the bearing cover and the base to adjust.

What is CRBH series crossed roller bearings?

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The structure of crossed roller bearings


The crossed roller bearings has 3 kinds of structure: Outer ring division type with inner ring rotating, inner ring division type with outer ring rotating, inner ring rotation / outer ring rotation. The rolling element is cylindrical roller which vertically aligned in a V-raceway with spacer separated from each other . This structure makes individual bearing can carry axial load, radial load and overturning moment in all directions. Meanwhile, the dimensions of these bearings are maximum miniaturized. Special ultra-thin structure size is close to the limits of miniaturization also with high rigidity. It is well applied on the joints or rotating parts of industrial robots, the turntable of the machining center, robot rotation parts, precision rotary table, medical equipment, measuring instrument and other applications.

CRBH series crossed roller bearing(Integrated Inner/outer ring type, ultrathin), the ultra-thin design without mounting holes on the outer ring and the inner ring, so it requires flange and supporting pedestal when installation. In addition, because the outer ring and inner ring are integral structure, installation has no impact on performance. ensuring stable rotation accuracy and torque. This series can be used for both inner-ring rotation and outer-ring rotation and the requirement of miniaturized dimension.-www.honbyrt.com

CRBH series（One-piece inner ring&outer ring，super slim） Unit：mm
Model Main dimensions Shoulder dimension Basic load rating(radial direction) Mass
Inner ring Outer ring Height Chamfer CR Cor

CRBH series（One-piece inner ring&outer ring，super slim） Unit：mm
Model Main dimensions Shoulder dimension Basic load rating(radial direction) Mass
Inner ring Outer ring Height Chamfer CR Cor
d D B rmin da Da kN kN kg
CRBH3510 35 60 10 0.3 41.5 53.5 7.9 9.1 0.13
CRBH4010 40 65 10 0.3 46.5 58.5 8.6 10.6 0.15
CRBH4510 45 70 10 0.3 51.8 63.5 8.9 11.3 0.16
CRBH5013 50 80 13 0.6 56 74 17.3 20.9 0.29
CRBH6013 60 90 13 0.6 66 84 18.8 24.3 0.33
CRBH7013 70 100 13 0.6 76 94 20.1 27.7 0.38
CRBH8016 80 120 16 0.6 88 112 32.1 43.4 0.74
CRBH9016 90 130 16 0.6 89 122 33.1 46.8 0.81
CRBH10020 100 150 20 0.6 110 140 50.9 72.2 1.45
CRBH11020 110 160 20 0.6 120 150 52.4 77.4 1.56
CRBH12025 120 180 25 1 132 168 73.4 108 2.62
CRBH13025 130 190 25 1 142 178 75.9 115 2.82
CRBH14025 140 200 25 1 152 188 81.9 130 2.96
CRBH15025 150 210 25 1 162 198 84.3 138 3.16
CRBH20025 200 260 25 1 212 248 92.3 169 4
CRBH25025 250 310 25 1.5 262 298 102 207 4.97

The right ways of installation method and steps about slewing bearing

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What are the steps to correctly install the slewing ring? The following is an example of how to install the slewing ring:

First, open the slewing bearing package, check the certificate and label, and confirm that the slewing bearing model used is correct.

1, the installation plane

The installation surface should be smooth and clean. Remove any excess material such as paint residue, beads, burrs, etc. Be careful not to let the solvent penetrate the inside of the slewing ring during cleaning, and do not use solvents that damage the sealing material. The mounting surface should be dry and free of lubricant before assembly. Measures should be taken to protect workers and the environment. The

The roughness of the mounting surface of the mounting bracket is not greater than Ra=12.5, 6.3μm. The flatness error of the mounting surface must detect the circumferential error and radial error. The circumferential flatness tolerance value has a corresponding standard value range with the diameter of the slewing bearing raceway.

In order to avoid unevenness of the mounting plane or local overload of the slewing bearing caused by the deformation of the support, the circumferential flatness error can only have one wave undulation in any 180 degree range, and the change is gentle.

2, the degree of support of the steel

Standard slewing bearings and zero-gap slewing bearings have different requirements for the rigidity of the bearings.

3, positioning

The inner and outer ring raceways of the slewing ring have a soft band and should be placed on both sides of the main load plane. That is, it is offset 90 degrees from the main load area. There is a blockage or “S” mark at the soft band.

In addition, check the match between the slewing bearing and the mounting surface. Usually, feeler check is used. If the fit is not good, use appropriate materials to fill. After the slewing bearing is installed, it is forbidden to carry out welding work on the bearing.

2. Slewing rings should be installed under no load conditions.

Note: Apply a bit of oil on the thread of the bolt to ensure a uniform balance of friction. Do not use glue on the bolt loose parts. Pre-tightening bolts: It should be pre-tightened in three steps. The three-step forces are 30%, 80% and 100% respectively.

1, adjust the gear backlash

When installing a toothed slewing bearing, it is important to correctly adjust the backlash of the gear. The feeler can be adjusted with a feeler gauge at the highest point of the radial runout of the gear, or it can be made of pressed wire or other suitable method. If the backlash is not within the specified value, the movable pinion changes the center distance. After setting, turn the slewing ring at least one full revolution to confirm that there is no other tooth high point. Check the backlash clearance after the slewing ring is finally fixed. The highest point of the radial runout of the gear is marked with green paint in the tooth gap.

2. Lubrication for the first time

At the time of manufacture, slewing bearing manufacturers usually add some grease, but before the slewing ring is officially used, the user must add enough grease!

3, roller lubrication

In order to ensure adequate lubrication, grease should be refilled prior to initial use on the drawings or product instructions. Pay special attention to all the grease nipples one by one. It is best to turn the grease while rotating the slewing ring until you see the grease squeeze out of the seal.

4, gear lubrication

When the gears are lubricated, the tooth surfaces should be clean. It is recommended to use a clean brush to brush the grease on the gear.

Third, regular inspection and maintenance

1. For the first time for 100 working hours, check the bolt preloading torque. If there are more than 10% loose bolts, check again in the 200th working hour. Every 500 working hours will be checked once; adverse conditions will be shortened. After 2,000 hours of equipment accumulative work, if a bolt is loosened to less than 80% of the specified torque, the bolt and the adjacent two

2, bolts to be replaced. If it is found that 20% of bolts loosen below 80% of the specified torque, all bolts must be replaced.

3. After the equipment accumulatively works for 14,000 hours, all bolts must be replaced. For equipment with high rotation speed or continuous rotation or frequent operation, add oil every 100 working hours. In the case of poor working conditions, the time interval for filling grease should be further shortened.

Existing form and working principle of excavator slewing bearing

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Excavator is one of the important equipment in modern engineering construction. The excavator can rotate left and right during work, which is inseparable from the credit of the slewing mechanism. It is one of the important components of the hydraulic excavator. The slewing mechanism is connected with the walking device through a slewing support, and the slewing drive device makes the platform rotate relative to the walking device and drives it to rotate around its central axis of rotation. Today, the editor will tell you about the existence and working principle of excavator slewing bearings for everyone to learn and understand.

1. The existence of slewing ring

1) rotary column slewing bearing

In the structure of the slewing column type slewing bearing, the rotating body and the supporting shaft form a rotating column, which is inserted into the bearing of the bearing seat. The bearing seat is bolted to the frame. The shell of the swing cylinder is also fixed on the frame, and its output shaft is inserted into the lower bearing. The rotating body is driven to rotate relative to the frame. The working device is hinged on the revolving body and revolves with the revolving body, and the rotation angle is not more than 180°.

  1. Rolling bearing type slewing ring

 

Rolling bearings are compared with ordinary bearings. The speed is very slow, and the commonly used structure has two types: single-row ball and double-row ball. The single-row ball slewing bearing is mainly composed of inner ring, outer ring, isolator, rolling element and upper and lower sealing devices. The steel balls are separated by rolling elements, and the inner ring or outer ring is processed into an inner ring or an outer ring.

 

The inner gear ring is fixed on the walking frame, and the outer ring is firmly connected with the rotary platform. The slewing drive device is fixedly connected to the slewing platform and generally consists of a slewing hydraulic motor, a planetary reducer, and a slewing drive pinion. Through the meshing transmission of the driving pinion and the ring gear, The rotary device revolves around the inner ring gear while rotating. Thereby driving the platform to rotate 360°.

  1. Working principle of transmission

 

When the excavator is working, the position of the combined force of the upper part of the turntable and the load is constantly changing, and is biased towards the direction of the load. In order to balance the load moment, each device on the turntable needs to be reasonably arranged, and a counterweight is set at the tail to improve the force of the lower structure of the turntable, reduce the wear of the slewing bearing, and ensure the stability of the whole machine.

 

As the speed increases, the flow rate required by the swing motor also increases. When all the oil of the hydraulic pump is supplied to the swing motor, the start phase ends. The accumulator releases its energy at this moment, so the hydraulic pump and the oil from the accumulator are supplied to the slewing motor together, which speeds up the speed of the slewing motor. This is the second stage of starting.

 

The above is a brief introduction to the existence form and working principle of the excavator slewing bearing. Here is a reminder that after the excavator is used for a period of time, its slewing bearing is prone to noise, impact and other faults. The operator should pay attention to observe and check in time to eliminate malfunction. Only correct and reasonable maintenance and maintenance of the slewing ring can ensure its normal operation, give full play to its performance and extend its service life.

The YRT turntable bearing

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The YRT turntable bearing is composed of a set of thrust / radial seat ring, a thrust / radial shaft ring, a thrust washer, two roller cage assemblies, and a set of radial cylindrical rollers. The seat ring and the shaft ring have evenly distributed screw holes for installation. This type of bearing has a high axial and high radial load carrying capacity, high tilting rigidity, and extremely high precision. It is suitable for the rotary table and devices in measurement and experiment. The YRT turntable bearing also has relatively high requirements for the matching equipment parts. During installation, the tightening torque of the mounting screws needs to be controlled.

Applications: It is widely used in precision rotary tables, vertical grinding machines, indexing heads, gear hobbing machines, gear milling machine workpiece shafts, and other precision devices.

YRT standard series turntable bearings:

The thrust-radial combined structure can bear bidirectional axial load, radial load, and overturning moment at the same time. The bearing is evenly equipped with mounting holes, which can be directly fixed to the bearing using bolts. The bearing has been pre-loaded at the time of installation, and there is no need to adjust the clearance during installation. YRT turntable bearing series is suitable for working conditions required of low speed, short operating cycle, high rigidity and accuracy, such as a rotary table, indexing head, etc.

The difference between upper slewing tower crane and lower slewing tower crane

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Tower cranes are commonly used lifting machinery equipment at construction sites, used to lift construction materials such as steel bars, wood corrugated, concrete, and steel pipes. One of the important parts of the tower crane is the slewing drive device. Tower cranes can be divided into lower slewing and upper slewing tower cranes according to the rotation mode of the tower body structure. Today we will talk about the difference between upper and lower slewing cranes.

The slewing drive is usually composed of worms, slewing bearings, housings, motors and other components. Since the core components of the structure are slewing bearings, it can bear axial force, radial force, and tilting moment at the same time. In the existing structural design of mechanical products, there are many forms of composition, but the types of structural parts are basically the same.

Upper slewing tower crane is with the slewing support, balance weight, and the main mechanism at the upper end. The advantage is that when the tower body does not rotate, the lower structure of the tower body can be simplified and the lifting and joints are convenient. The disadvantage is that when the building exceeds the height of the tower, the rotation of the crane is restricted due to the influence of the balance arm. At the same time, the center of gravity is higher, the wind pressure increases, and the weight increases, which increases the total weight of the whole machine.

The tower body of the jack-up tower crane is also assembled by standard sections, which is actually a kind of assembled tower crane. But it is also equipped with a jacking and sectioning system. After installation, it can be jacked and sectioned at any time. This feature is more prominent. The advantage of jack-up tower crane is that it can be attached and can be raised very high, so it is especially suitable for middle and high-rise buildings and bridge construction. It is the most common use tower crane in my country’s existing tower cranes. Jack-up tower cranes are all top-rotating, because they have to be attached and do not allow the tower to rotate.

The lower slewing tower crane is with the slewing support, balance weight and main mechanisms at the lower end, the boom is installed on the top of the tower body, and the tower body, counterweight and all mechanisms are installed on the turret and rotate together with the turret. . This type of tower crane has a low center of gravity, good stability, and small bending moments on the tower body (the bending moment of the upper slewing tower crane is borne by two diagonally arranged main chords, and the lower slewing tower The bending moment is shared by the four chords). In addition, because the balance weight is placed in the lower part, it can be erected by itself and transported as a whole. The disadvantages are: higher requirements for the slewing support, and limited use height. The cab is generally set on the lower turret, and the operating sight is not open.

The Wide range application of slewing bearing

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With the rapid development of machinery industry, the application range of slewing bearing has been gradually expanded, and slewing bearings have been widely used instead of original bearings. Construction machinery is the initial application of slewing bearings is also the most widely used places, such as earth-moving machinery, excavators, dismantling machines,heap picking machines, graders, rollers, tamping machines, rock drilling machines, boring machines and so on.

Slewing bearing applications are:

(1) Engineering ships: dredgers
(2) feeding machinery: disc feeder, sand mixer
(3) Concrete machinery: concrete pump truck, concrete mixing cloth rod machine, belt cloth machine
(4) Light Industry Machinery: Beverage Machinery, Bottle Blowing Machine, Packaging Machinery, Filling Machine, Rotary Bottle Finisher, Injection Molding Machine
(5) Special vehicles: bridge detection vehicles, fire engines, gondola machines, flat girder trucks, aerial vehicles, self-propelled aerial work platforms
(6) Crane type: Wheel Crane, Crawler Crane, Portal Crane, Tower Crane, Forklift, Crane, Gantry Crane
(7) Foundation 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, submersible engineering drilling rig, static pressure pile Machine, pile driver and so on.
slewing ring bearings have wide product range that are widely used in above applications like standard Single row four point contact slewing bearing,Cross roller slewing bearing,Three row roller slewing bearing and light small slewing bearings, precision slewing bearing

If you need the slewing bearing for the above application field, please kindly contact us

Email:daisy@hgb-bearing.com

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

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

 

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

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

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

B; roller type: add grease every 50 hours of operation.

 

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

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

Since the slewing bearing is installed, the pre-tightening force of the bolts should be checked after 100 hours of operation. After that, the pre-tightening force of the bolt should be checked every 500 hours. Sufficient and best efforts must be maintained.

  1. After the equipment has been working for 2000 hours, if a bolt is found to be loose below 80% of the specified torque, the bolt and two adjacent bolts shall be replaced with new ones; if 20% of the bolts are found to be loose to 80% of the specified torque Below, all bolts are replaced with new ones. After the equipment has been working for 14,000 hours, all bolts should be replaced with new ones (Suggestion: after two to four months use, re-firm the solid parts, and then transition to an annual systematic inspection).

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

  1. ​​When the slewing ring is in use, it is forbidden to directly wash the slewing ring with water to avoid water entering the raceway to cause rust; strictly prevent hard foreign objects from approaching or entering the meshing area to avoid tooth injury or unnecessary trouble.
  2. To keep the surface of the slewing bearing clean, choose a suitable solvent for cleaning according to the surface properties of the anti-rust object, so as to avoid serious corrosion. Surface cleaning can use chemical treatment cleaning method and mechanical cleaning method. When the surface is dry, do a good job in controlling the temperature and wait until most of the area is dry before wiping it with gauze. When applying anti-rust oil, different methods should be adopted to apply different methods of bearing surface properties. Miniature bearings can be directly soaked in anti-rust grease. If you encounter a special shape, you can choose the painting method, so that it is not easy to produce accumulation. There are many factors that cause metal corrosion. The chemical composition of the metal itself can also cause corrosion or the temperature and humidity of the environment in which the item exists can also cause corrosion.
  3. The sundries on the surface of the slewing ring should be removed frequently during use, and the sealing strips of the slewing ring should be checked for aging, cracking, damage or detachment. If one of these conditions occurs, the sealing strips should be replaced in time to prevent debris and debris from entering the raceway. If the grease is lost, the corresponding grease should be applied after replacement to avoid jamming or rusting of rolling elements and raceways.

 

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

What are the components of the turntable bearing

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The turntable bearing is also called the slewing bearing，It is a kind of large bearing which can bear large axial load, radial load and overturning moment simultaneously.turntable bearings are generally equipped with mounting holes ,internal or external, gear oil holes and sealing devices
Therefore, it can make the structure design of the main engine compact, guide reliable and maintain conveniently.widely used in lifting machinery, construction machinery, transport machinery ,material processing machinery, metallurgy machinery ,food processing machinery and military equipment, medical scientific ,research equipment and so on .The components of the turntable bearing are different because of the difference of the structural design,let us intruduce the strcture of slewing bearing

1.Inner ring

The characteristics of the inner ring are usually thin and strong, Its production accuracy is often required to be within a few tenths of a millimeter,therefore, whether this part is in place is also one of the key areas of the whole bearing quality inspection

2.Outer ring
The outer ring is an object that combines the inner ring with the rest of the machine,therefore, the quality of the outer ring is also crucial for the turntable bearing,the outer ring is thicker
the wear and tear is important, and it needs to be made of a stronger material

3.The rolling elemen
The rolling body facilitates the rotation of the relative rings between the inner and outer ,Rollers are also often used as rolling elements.the rolling bodies of rotary bearings are usually separated by nylon isolation blocks.the structure was widely used because it kept the motion stationary and was inexpensive,Special applications require the use of special ball or roller isolation block, such as copper and aluminum high temperature isolation fast,For bearings usually mounted on horizontal shafts or continuously rotating generators and for rotary plate bearings used in situations where positioning and reliability are high requirements, a strip combined retainer may be used to provide greater reliability in keeping the rolling body in the correct circumferential position

4.The sealing element
Both sides of the slewing bearing have seals,Its main function is to maintain oil and grease,Prevent contaminants such as dust and debris from entering,seals are usually made of pressed rubber strips

5.The taper pin
Due to the different nature of the hardening process of different types, the hardness of each type is different,In the position used for non-gear ring or in the outer ring for non-gear ring drilling the ball can be loaded into the rotary ring assembly,Drilling allows the ball to be loaded into the rotary ring assembly,The hole is inserted and fixed with a tapered pin,But for rings that do not exist to load plugs,The word S is printed at the position of the unhardened clearance of the ring.

6.Pinion
Slewing bearing may be working without gear,Pinion can also be used on the inside diameter of the inner ring or the outside diameter of the outer ring,the gear is usually a standard short – cut involute spur gear

7. Nozzle
At least one grease fitting is included in one of the rings,the quantity may increase with the increase of the diameter of the slewing bearing,for bearings with pinion, the grease connector is located on the inside or outside diameter of the ungear ring,for rough bearings,The slewing bearing may be fitted with grease fittings on the inner or outer rings

The above is a detailed explanation of the structure composition of the turntable bearing