Effective utilization and adjustment of slewing bearing clearance

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.


Slewing bearing different structure, different advantages

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,


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

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.

What are the factors to be considered when selecting a slewing drive device?

The slewing drive we often say is actually a full-circle slewing reduction transmission mechanism integrated with a driving power source. It takes a slewing bearing as a drive follower and mechanism attachment. It makes one of the rings ( inner ring or outer ring) to be attached as the driving part, the driving source and the cover, and the other ring as the transmission follower and the connection base of the driven working part. In this way, it can make use of the characteristic of the slewing bearing which is a full-circle slewing connection to configure efficiently the driving power source and main transmission parts. And finally make it to be a universal reduction transmission mechanism that integrates the functions of rotation, reduction and driving, while having a simple structure and convenient manufacturing and maintenance. At present, there are many types of slewing drive devices. What are the factors to be considered when selecting a slewing drive device?

1. Magnitude, Direction and characters of the load
The slewing drive device is suitable for light loads, and the roller bearing is suitable for heavy loads and shock loads. When the rolling bearing is subjected to pure axial load, thrust bearing is generally selected; when the rolling bearing is subjected to pure radial load, deep groove ball bearing or short cylindrical roller bearing is generally selected; when the slewing device is subjected to pure radial load, and with not large axial loads, deep groove ball bearings, angular contact ball bearings, tapered roller bearings and self-aligning ball or spherical roller bearings can be selected; When the axial load is large, the angle contact bearing and tapered roller bearings ca be selected, or use a combination of radial bearings and thrust bearings, which are particularly suitable for extremely high axial loads or special requirements for greater axial rigidity.

2. Allowable speed
Due to big differences of types of slewing drive, bearings with low friction and low heat are suitable for high speeds generally. During the design, the slewing rolling bearing should considered to be work under the condition of lower than its limit speed.

3. Rigidity
When the bearing of the slewing drive device bears a load, elastic deformation occurs at the contact between the bearing ring and the rolling element. The amount of deformation is proportional to the load, and the ratio determines the rigidity of the bearing. Generally, the rigidity of the bearing can be improved by preloading the bearing; In addition, in the bearing design, considering the combination and arrangement of the bearing can also improve the support rigidity of the bearing.

4. Alignment performance and installation error
After the bearing is installed in the working position, it is often poor in installation and positioning due to manufacturing errors. At this time, the bearing is often subjected to excessive load due to the fishing degree and thermal expansion of the shaft, causing early damage. The self-aligning bearing can overcome the defects caused by the installation error by itself, so it is the bearing suitable for this purpose.

5. Installation and disassembly of slewing drive device

Tapered roller bearings, needle roller bearings and etc., belong to the type of bearing with separable inner and outer rings (so-called separate bearings), which are easy to install and disassemble.

It is a brief introduction to the factors that need to be considered when selecting the slewing drive device above. The slewing drive can be used in any situation that requires full rotation and variable speed requirements. When it is necessary to achieve greater torque power transmission and higher precision motion transmission Or when selecting a mechanism that requires a high degree of compact body structure and integration, slewing drive is the solution. In addition, the slewing drive device is convenient to install and saving space. When selecting the model, first consider whether the shaft radial load, overturning torque and other parameters are workable for use. Secondly, the final output speed of the slewing drive cannot exceed 3 revolutions during use, in order to ensure the product normal service life.

The larger OD 4m slewing bearing for bucket-wheel stacker reclaimer

We have ship the big size three row cross roller slewing bearing to Customer On July 20 ,2020

The larger OD 4m slewing bearing for bucket-wheel stacker reclaimer

Three-row roller slewing ring has 3 seat-rings,Upper Orbit,Nether Orbit and Radial Orbit are separated individually,it makes the load of each row of the rollers can be confirmed,so it can undertake all kinds of different load simultaneously and it’s Carrying Capacity is the biggest among four models,one more thing,the axial&radial size are rather large to some extent and the structure is very firm,so it is especially suitable for many heavy-duty machines which require bigger diameter,such as,Bucket-Wheel Excavator,wheeled Crane,Shipyard Crane,heavy-duty Truck Crane,and so on.

It is especially suitable for many heavy-duty machines which require bigger diameter,such as,Bucket-Wheel Excavator,wheeled Crane,Shipyard Crane,heavy-duty Truck Crane,and so on.

The excavator Liebherr 904 ,934 slewing bearing and shaft for Russia customer

We successfully completed the production of slewing bearings of liebherr 904 and 924 934 slewing bearing and shaft in April

In may we shiped to customer details address , he was very Satisfied with the quality and then will have other order of excavator slewing bearing .he said very gald  have the long-term cooperation with us .

Professional technical support and best service are our strength, when we got the enquiry of bearing from customer ,Fastest response we can give and then send the specific Solutions to customer

Rotek slewing bearings we can customized

Rotek Series 2100 slewing ring

External gear

L6-16N9Z, L6-16N9ZD, L6-22N9Z, L6-16N9ZD, L6-25N9Z, L6-25N9ZD, L6-29N9Z, L6-29N9ZDL6-33N9Z, L6-33N9ZD, L6-37N9Z, L6-37N9ZD, L6-43N9Z, L6-43N9ZD

L9-38N9Z, L9-42N9Z, L9-46N9Z, L9-49N9Z, L9-53N9Z, L9-57N9Z

Internal gear

L6-16E9Z, L6-16E9ZD, L6-22E9Z, L6-22E9ZD, L6-25E9Z, L6-25E9ZD, L6-29E9Z, L6-29E9ZDL6-33E9Z, L6-33E9ZD, L6-37E9Z, L6-37E9ZD, L6-43E9Z, L6-43E9ZD

L9-38E9Z, L9-42E9Z, L9-46E9Z, L9-49E9Z, L9-53E9Z, L9-57E9Z


L4-13P8Z, L4-13P9Z, L4-17P8Z, L4-17P9ZL6-16P9Z, L6-16P9ZD, L6-22P9Z, L6-22P9ZD, L6-25P9Z, L6-25P9ZD, L6-29P9Z, L6-29P9ZDL6-33P9Z, L6-33P9ZD, L6-37P9Z, L6-37P9ZD, L6-43P9Z, L6-43P9ZD

L9-38P9Z, L9-42P9Z, L9-46P9Z, L9-49P9Z, L9-53P9Z, L9-57P9Z

Rotek Series 3000 slewing ring

External Gears

A6-9E1B, A6-11E4, A6-14E10, A8-17E10BC, A12-18E5, A14-18E1L, A8-19E5A, A8-22E6

A10-22E5A, A12-22E2, A14-22E1B, A12-27E3, A8-30E8D, A10-34E6, A12-34E2AG, A14-34E31

A13-38E1, A8-39E12, A8-41E1, A12-42E3, A18-46E4D, A10-47E1, A12-48E12, A14-48E22

A16-53E1A, A18-60E2, A18-74E3, A16-78E4, A18-80E1, A18-89E1, A22-105E2A, A19-111E1

A24-119E11A, A16-152E2

Internal Gears

A8-17N4D, A8-22N2A, A8-25N2, A9-25N3, A10-32N1A, A14-33N1, A10-35N1L, A12-35N5,

A7-38N1, A10-43N28D, A13-46N1A, A12-47N3E, A14-47N5A, A9-54N2, A14-54N10C, A16-59N2

A20-72N5A, A18-80N1, A16-95N6, A20-95N4, A24-107N1, A22-129N1, A22-166N1


A6-9P4, A6-11P5, A-14P3D, A8-17P1DU, A14-19P4, A8-22P11, A13-22P4, A4-23P2A, A9-24P2

A14-24P1A, A14-25P1, A14-31P3, A12-32P2, A12-34P2B, A10-35P1A, A14-43P1, A12-47P2

A14-49P1A, A14-56P1E, A18-60P1B, A16-67P2, A16-79P1A, A16-86P1, A14-89P1, A18-89P1

A22-98P1, A10-110P2D, A12-125P1, A19-150P1

Rotek Series 4000 slewing ring

H7-30E1, H7-38E1, H8-58E2, H7-35N1

Rotek Series 5000 slewing ring

R8-30E3, R8-35E3, R8-39E3, R8-42E3, R8-44E3, R8-46E3, R8-49E3, R8-52E3, R8-55E3

R8-59E3, R8-63E3

Rotek Series 10000 slewing ring

3R6-48E3B, 3R6-49E9, 3R6-55E9, 3R6-63E9, 3R6-71E9, 3R6-79E9, 3R8-79E9, 3R8-88E9

3R6-98E9, 3R10-82E3C, 3R16-197E2

Rotek Series 3000 Bearings

Internal Gears

A8-20N2A, A8-22N2A, A8-22N9, A8-25N1, A8-59N8, A10-22N1B, A10-35N1M, A10-35N14, A10-36N2, A10-42N6, A10-43N28D, A10-48N6B, A10-49N1, A12-30N2, A12-39N3B, A12-43N12, A12-49N8, A12-52N7, A14-29N7, A14-29N1, A14-36N4A, A14-47N5A, A14-49-N12, A14-54N10C, A14-61N3B, A16-58N6B, A16-59N1E, A18-52N11, A18-68N4, A20-55N1, A20-69N1, A20-95N1M, A22-55N17, A22-64N8, A22-79N2, A22-97N1A, A24-79N1E, A24-96N1, A24-107N1,

Gearless Bearings

A7-11P1, A8-11P1AF, A8-19P2B, A8-20P6, A8-22P1, A8-25P1B, A8-41P1, A8-60P1A, A10-23P3A, A10-30P1D, A10-39P4, A10-43P4, A10-55P4, A10-67P1, A12-22P3, A12-30P1, A12-50P1, A12-75P1, A14-24P1B, A14-31P2, A14-56P1C, A16-38P1, A16-77P1, A18-38P1, A18-60P1, A18-85P1, A20-40P1, A20-72P1A, A20-98P1C, A22-98P1, A24-58P1, A24-99P1, A24-119P4.

Heavy duty big diameter slewing bearing

Our factory also can manufacturered the big size high-stabilitys high duty slewing bearing with outer diameter 5m that meet clients details enquiry

.The big size slewing bearing are widely used in offshore floating crane , stacker and reclaimer, harbor crane and other heavy duty equipment.

The strong technical team our factory have , if you have any related demand of slewing bearing , just contact us
Personalized customization you will get depend on our strong team and skilled technique in our factoury .we can meet your heavy duty application demands.

For Bucket wheel reclaimer                 For ship unloaders

Delivery SDE3 Dual Axis Slewing Drive to Australia

On December 12, 2019, Luoyang Hengguan Bearing company delivery three sets of SDE3 with two 24V motor slewing drive to Australia by Air.

The dual-axis slewing drive can adjust the horizontal movement and the pitch angle. It is an important device for solar tracking systems. Luoyang Hengguan can quote prices and freight to customers as fast as possible, providing the best products and services.


We seek to be representative of China top quality machinery supplier.

The Nk-450BV Crane Slewing Bearing Arrived to Repair Factory

The Nk-450BV crane slewing bearing arrived to repair factory at 27th, November .

The customer is very satisfied with the quality and packing.


This slewing bearing structure is four-point contact ball with internal teeth,
1.this series ball slewing bearing is composed of outer and inner race, the rolling elements and the spacing block.
2. The single-row of rolling balls is located in the raceway between the outer and inner races.
The ball slewing bearing is widely used in the fields of construction machinery, marine machinery, as well as kinds of cranes, excavators, transportation machinery, wind power generators and military machinery.

And all slewing bearing we manufacture were strict inspection,clean,rust-proof treatment ,waterproof packing , single box to fit long transportation before delivery .
so we can give the better experience for all customer .also our engineer provided full
technical guidance during installation.