What are the commonly used materials of slewing bearing

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Slewing bearings, also called slewing bearings, are often used in engineering and manufacturing machinery, such as excavators, roadheaders, wind power equipment, industrial robots, port machinery and other equipment. Slewing bearings are usually composed of ferrules, rolling elements, cages, and sealing rings. Because different parts have special functions in practical applications, there are different considerations in the design and selection of materials. Today I will tell you what are the commonly used materials for slewing bearings.

One,Materials for gear ring and rolling element
In general, the rolling elements of the slewing ring adopt integrally hardened carbon-chromium bearing steel. The grade is made of GCr15 or GCr15SiMn steel; the slewing ring is made of surface hardened steel. When the user has no special requirements, it is generally made of 50Mn steel, but sometimes in order to meet the needs of the host in some special applications, it can also be provided by the user. For specific use conditions, select other grades of surface hardened steel, such as 42CrMo, 5CrMnMo, etc.
The medium and small slewing bearing forgings all use round or square bars 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 properties can be forged without large forging deformation. Ingots are only used for large forgings. The ingot is a cast structure with large columnar crystals and a loose center. Therefore, it is necessary to break the columnar crystals into fine grains through large plastic deformation, and compact the looseness to obtain excellent metal structure and mechanical properties.

Two. Material for cage
The cage for slewing support has a structure such as an integral type, a segmented type, and a spacer type. One-piece and segmented retention
The frame is made of No. 20 steel or ZL102 cast aluminum alloy. The isolation block is made of polyamide 1010 resin and ZL102 cast aluminum alloy. In recent years, with the continuous development of the material industry, nylon GRPA66.25 has also been promoted and applied in the design of segmented cages.

Common materials for slewing bearings

Three. Materials for sealing ring
The slewing ring is made of oil-resistant nitrile rubber, oil-resistant rubber and fluorine rubber. The material used for the seal must be able to withstand a large operating temperature range and have a certain chemical resistance.

The code of the ferrule material and the supply status of the blank shall be as specified in the table. In the table, “T” means that the ferrule blank is supplied in a quenched and tempered state, and “Z” means that the ferrule blank is supplied in a normalized state.

code number 01 02 03 04 05 06.

Material and blank state 45BT 45BZ 42CrMoT 42CrMoZ 5CrMnMoT 5CrMnMoZ.

code name 07 08 09 10 11 12.

“Material and blank state 42SiMnT 42SiMnZ 45MnT 45MnZ 50MnT 50MnZ.

The diameter of the center circle of the rolling element is 3150mm, the ball diameter is 75mm, the gear modulus m=20mm, the ring material is 50Mn, and the blank material is normalized. The internal tooth type four-point contact ball will be transferred to the bearing expressed as 013.75.3150.12 .
The above is a brief introduction to the commonly used materials of slewing bearings. Luoyang Hengguan is a comprehensive entity enterprise of slewing ring/slewing table bearings integrating design, R&D, production, sales and service. Mainly produce slewing ring/slewing table bearings with a diameter of 50-9800mm and various high-precision slewing bearings, large thrust ball bearings, non-standard shaped bearings and other products. The accuracy covers four levels of P0, P6, P5, and P4. The product types include single-row Four-point contact ball structure, cross cylindrical roller structure, three-row cylindrical roller structure, double-row ball slewing ring, ball-column joint structure, thin-walled flange structure, large thrust ball structure, etc. Friends in need are welcome to call for detailed consultation.

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.

Analysis and Solution of Inflexible Slewing Ring Operation

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The slewing bearing is called the joint of the machine. It is a common used bearing in modern machinery and equipment，which requires relative rotational movement between two objects and simultaneously bears axial force, radial force and tilting moment. With the rapid development of the machinery industry, slewing bearings have been widely used in marine equipment, engineering machinery, light industry machinery, metallurgical machinery, medical machinery, industrial machinery and other industries. However, Some slewing bearing is inflexible in operation or it is found that the slewing bearing will rotate inflexibly after being put into use for a period of time. Faced with such a problem, how should we deal with it? The following is an explanation of the reasons and solutions for the inflexible operation of the slewing ring.

  1. First, do the following investigations on abnormal phenomena
  2. Idling of newly purchased products is not flexible

Please check the production date of the slewing bearing. If it takes a long time, such as more than half a year, and the climate is cold, it is possible that the viscosity of the grease in the raceway may be too large and the operation will not work. It is more prominent in cold areas and winter.

Exclusion method: If it can be operated and there are no other abnormalities after adding force, it can be used normally; if it is accompanied by abnormal noise, check whether there is any serious trauma during transportation, and report the information to the manufacturer’s after-sales service department for processing.

2. Inflexible operation after installation
It may be because the mounting surface of the main machine and the mounting surface of the slewing ring are not well matched, the axial clearance of the slewing ring after installation cannot compensate for the deformation of the slewing ring. The slewing ring is in a state of negative clearance and the rolling elements are difficult to run in the raceway, sometimes accompanied by abnormal noise , Or poor meshing of the large and small gears, or foreign matter stuck in the large and small gears.
Solution: Re-process the installation plane to make the installation plane meet the requirements, or use the gasket filling method; re-adjust the meshing backlash of the large and small gears as required, especially pay attention to the position of the gear jump; check to ensure that there is no foreign matter in the meshing position of the large and small gears; Replace a slewing bearing with a slightly larger clearance.
2. Reasons for inflexible rotation during use
1. The slewing bearing lacks lubricating oil, and the lubricating grease causes increased friction and resistance, which will cause insensitive movement.
Solution: add the same specification lubricating oil or replace all the lubricating oil.
2. The sealing strip is damaged, causing foreign matter to enter the raceway, such as poor working conditions, dust intrusion into the raceway, etc.
Solution: Remove foreign objects in the raceway and replace the sealing strip.
3, the slewing ring gear is deformed or broken, causing jamming or inflexible movement.
Solution: repair the gear and re-weld the gear.
The above is the analysis of the reasons for the inflexible operation of the slewing ring and the solutions. If the slewing ring still cannot be rotated after taking the above measures, it may be a fault in the raceway, please contact the manufacturer in time for after-sales treatment. For more information about slewing ring bearings, please pay attention to this website, or contact us.

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