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.

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 engineering 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 role 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 size of 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 precise 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 matching of 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 increase, and it will not work normally, 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 working clearance is determined by the application conditions (load, speed, design parameters) and 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 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 direction

 

For load or occasions where the self-aligning performance needs to be improved, a large clearance group should be used.

 

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 cap and the base to adjust.

 

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.

Slewing bearing different structure, different advantages

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Single row/double row Ball Slew Ring Bearings
The single-row four-point contact ball slewing bearing is composed of two seat rings.
Designed for average axial forces and tilting moments as well as high radial forces
Compared with the single-row version, the double row bearing can support higher loads at the same diameter
Applications: Mechanical engineering, construction equipment, wind turbines and ship loading/unloading applications

Double-Axial Ball Slew Ring Bearing
Simple and robust design with sufficient clearance
When tilting moments quickly change their amount and location
Where the slewing ring is subjected quick and continuous load changes
Applications: Open pit mining machinery like bucket-wheel excavators

Three-Row Roller Slew Ring Bearing
Used in highly demanding conditions
High static and dynamic load-carrying capacities
Applications: Rolling mill equipment, heavy-duty cranes and tunnel boring machines, mining machineries, etc,

news12-26-6

Cross-Roller Slew Ring Bearing
Used to support high radial forces as well as average axial forces and tilting moment loads
Zero clearance and uniform bearing friction
Applications: Mechanical and plant engineering, medical device and antenna equipment

Combi Slew Ring Bearing
Used in conditions of high axial forces and relatively low tilting moment loads
Applications: Bulk handling and conveyance equipmen

Types, Characteristics and applications of slewing bearing

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With the continuous advancement of technology in recent years, machinery industry has achieved rapid development, which has also driven the market demand for slewing bearings. Slewing bearing is called the joint of the machine or the large-scale mechanical rotation bearing, which can withstand the combined loads such as the larger axial load, radial load and overturning moment during operation. Do you know the types and characteristics of slewing bearings?

Due to its compact structure, easy to guide rotation, easy installation and easy maintenance, slewing bearings are widely used in engineering, mining, metallurgy, wind power, ships, ports, petroleum, chemical, light industry, medical equipment, food, and vehicles. , Robotics, aerospace, radar, and military industries.

Common types of slewing bearings are single-row, double-row four-point contact ball slewing bearings, double-row angular contact thrust ball slewing bearings, crossed cylindrical roller and crossed tapered roller slewing bearings, three-row cylindrical roller slewing bearings, and ball-column hybrids structures slewing bearings.

 Types of slewing bearings

　　　1) Single row cross roller slewing bearing

Composed of two seat rings, compact structure, high accuracy, small assembly clearance, high requirements for installation accuracy, the rollers are in 1:1 cross arrange , can bear axial force, tilting moment and large radial force at the same time , Is widely used in transportation, engineering machinery and military products.

　　2) single row four-point contact ball slewing bearing

　　It is composed of four parts: inner ring, outer ring, steel ball, and spacer. It has a relatively compact structure, light weight, four-point contact between the steel ball and the arc raceway, and can bear axial and radial forces at the same time. Construction machinery such as rotary conveyors, welding manipulators, small and medium-sized cranes and excavators can select this type.

　　 Four-point contact ball slewing bearing. It is also a bearing with two rings. Compared with a cross roller bearing, the steel ball and the track are in contact at four points, and it can also carry forces in the axial and radial directions.

      3) double row ball slewing bearing

　　It is constructed with three races. The steel balls and spacers can be directly discharged into the upper and lower raceways. According to the stress conditions, two rows of steel balls with different diameters are arranged. This kind of open assembly is very convenient. The load-bearing angle of the upper and lower arc raceways is 90°, which can bear great axial force and tilting moment. When the radial force is greater than 0.1 times the axial force, the raceway must be specially designed. The axial and radial dimensions of the double-row reducing ball slewing ring are relatively large and the structure is tight. It is especially suitable for loading and unloading machinery such as tower cranes and truck cranes that require medium and above diameters.

　　4) three-row roller slewing bearing is composed of three races, the upper and lower and radial raceways are separated, so that the load of each row of rollers can be accurately determined. It can bear various loads at the same time. It is one of the four products with larger axial and radial dimensions and a firm structure. It is especially suitable for heavy machinery requiring larger diameters, such as bucket wheel excavators and wheeled excavators. Cranes, ship cranes, port cranes, molten steel moving platforms and large-tonnage truck cranes and other machinery.

　　5) light series slewing bearing

　　 Light weight slewing bearing has the same structure as ordinary slewing bearings, light weight and flexible rotation. It is widely used in food machinery, filling machinery, environmental protection machinery and other fields.

  1. Application of slewing bearings

　　1) Construction machinery

Construction machinery is a application where slewing bearings are initially and widely used, such as earthmoving machinery, excavators, dismantling machines, stackers and reclaimers, graders, road rollers, dynamic compactors, rock drilling machines, roadheaders, etc.

　　2) Wind power generation field

　　 Wind turbine bearings usually include yaw bearings, pitch bearings, transmission system bearings (main shaft and gearbox bearings). Yaw bearings and pitch bearings are provided to customers. The yaw bearing is installed at the connection between the tower and the cabin, and the pitch bearing is installed at the connection between the root of each blade and the hub. Each wind turbine uses one set of yaw bearings and three sets of pitch bearings.

      3) solar field

　Rotating solar panels are a good solution to increase energy. Because the bearing has a very compact design, it supplies solar farms in Europe.

　　4) the field of medical equipment

　　The high-precision, low-noise, long-life, and high-reliability series of medical equipment spindle slewing bearings have been widely used in large medical equipment such as gamma knives, CT machines, and nuclear magnetic resonance machines.

　  The above is an introduction to the types and characteristics of slewing bearings. Different types of slewing bearings can meet different load conditions according to different structural characteristics.

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