What is the material used to make the slewing bearing

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The common structural forms 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, balls Different structural forms such as column hybrid slewing bearing. Although the structure is different, the materials used are similar, and the material of the slewing bearing directly determines the performance and service life of the bearing. Today, the editor will take everyone to understand what materials are used for the slewing bearings.

1. Material for ferrule and rolling element

Because the bearing should have the characteristics of long life, high precision, low heat generation, high speed, high rigidity, low noise, high wear resistance, etc., it is required that the bearing steel should have the characteristics of high hardness, uniform hardness, high elasticity, and high limit. .

Under normal circumstances, the slewing bearing rolling element adopts integrally hardened carbon chromium bearing steel. The grade is made of GCr15 or GCr15SiMn steel; the slewing bearing 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.

(1) 42CrMo is a high-carbon steel with good quenching and tempering performance and quenching performance. It is an ideal material for slewing bearings.

(2) 50Mn has good hardenability and is also a high-quality choice for slewing bearings.

(3) 40Cr is also good in terms of mechanical properties, and it is still in the stage of exploration and practice.

(4) GCr15 small slewing bearing can be selected, but it is generally not recommended to use it because of the trouble of milling and drilling in the process due to the full quenching.

Slewing bearing

2. Material for cage

The cage for slewing bearings has a structure such as an integral type, a segmented type, and a spacer type. Among them, the integral and segmented cages are made of No. 20 steel or ZL102 cast aluminum alloy. The isolation block is made of polyamide 1010 resin, ZL102 cast aluminum alloy, etc.

3. Sealing ring materials

The slewing bearing seal ring is made of oil-resistant rubber or nitrile rubber.

The code of the ferrule material and the supply status of the blank is in accordance with the regulations in the table. In the table, “T” indicates that the ferrule blank is supplied in the quenched and tempered state, and “Z” indicates that the ferrule blank is supplied in the normalized state.

The slewing bearing seal ring is made of oil-resistant rubber or NBR nitrile rubber. Compared with nitrile rubber, hydrogenated nitrile rubber has better oil resistance, but if you are not too demanding on oil resistance, use nitrile rubber, because hydrogenated nitrile rubber is relatively expensive. Nitrile rubber also has a certain degree of acid and alkali resistance. However, silica gel should be selected if the requirements for oil resistance and acid and alkali are higher, but its price is higher.

In summary, we know that the materials used in slewing bearings are related to their main body and parts. The main body is made of metal, while other parts, such as seals, are made of rubber. If you need this kind of bearing, you must pay attention to the integrity of these materials and high-quality effects when purchasing to ensure the function of the operation. Luoyang Hengguan Bearing provides high-quality, high-performance slewing bearing products for market customers. Everyone is welcome to call for detailed consultation.

Why do industrial robots need a reducer?

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In recent years, industrial robots have ushered in explosive development, especially due to the increase in labor costs, making manufacturing companies increasingly favor the use of more mechanized, more efficient, and lower-cost robots. When it comes to robots, we have to mention one of the important components, the reducer, which is what we often call the reducer. Due to the different operating environments and performance of industrial robots, the types of reducers used are also different. So, do you know why an industrial robot needs a reducer?

 

The power source of an industrial robot is generally an AC servo motor. Because it is driven by a pulse signal, the servo motor itself can realize speed regulation.

 

Industrial robots usually perform repeated actions to complete the same process; in order to ensure that industrial robots can reliably complete process tasks in production and ensure process quality, the positioning accuracy and repeat positioning accuracy of industrial robots are very high. Therefore, to improve and ensure the accuracy of industrial robots, rv reducers or harmonic reducers are needed. Another role of precision geared motors in industrial robots is to transmit greater torque. When the load is large, it is not cost-effective to blindly increase the power of the servo motor. The output torque can be increased by a reducer within a suitable speed range.

 

In addition, the servo motor is prone to heat generation and low-frequency vibration under low-frequency operation, which is not conducive to ensuring accurate and reliable operation of industrial robots that work for a long time and periodically. The existence of the precision geared motor enables the servo motor to run at an appropriate speed, and accurately reduces the speed to the speed required by each part of the industrial robot, which improves the rigidity of the mechanical body while outputting greater torque. Compared with general-purpose reducers, robot joint gear motors are required to have the characteristics of short transmission chain, small size, high power, light weight and easy control. There are two main types of reducers widely used in articulated robots: rv reducers and harmonic reducers.

 

Industrial robots usually perform repeated actions to complete the same process; in order to ensure that industrial robots can reliably complete process tasks in production and ensure process quality, the positioning accuracy and repeat positioning accuracy of industrial robots are very high. Therefore, to improve and ensure the accuracy of industrial robots, RV reducers or harmonic reducers are needed. Another role of precision reducers in industrial robots is to transmit greater torque. When the load is large, it is not cost-effective to blindly increase the power of the servo motor. The output torque can be increased by a reducer within a suitable speed range. In addition, the servo motor is prone to heat generation and low-frequency vibration under low-frequency operation, which is not conducive to ensuring accurate and reliable operation of industrial robots that work for a long time and periodically.

 

The reducers commonly used in industrial robots include RV reducers and harmonic reducers. Harmonic reducers are mainly used for light-loaded parts such as forearms, wrists, and hands. The RV reducer has a large transmission ratio range, relatively stable accuracy, high fatigue strength, and higher rigidity and torque carrying capacity.

 

In recent years, as the market for industrial and life assistance robots continues to expand, the demand for high-precision small modulus gears in precision reducers used in the joints of robots has also increased sharply. The robot-specific slewing ring (slewing bearing) products produced by Luoyang Hengguan have the advantages of light weight, high precision, reasonable price, and excellent service; our company has a professional production line for such products, which specializes in the production of such high-precision slewing bearings. It is also one of the main product series of our company. You are welcome to call for consultation and look forward to cooperating with you.

What are the four forms of failure of slewing ring raceway

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The life of the slewing ring raceway is determined by the quality of its own products and subsequent maintenance. It is even considered “three-point quality and seven-point maintenance”. The following phenomena generally occur after the raceway is damaged and failed: large gaps, oil leakage, jamming, abnormal noise, iron powder and even iron pieces on the raceway, etc. There are many reasons for the failure of the bearing. Today, the editor will introduce four common failures of the slewing ring raceway. For everyone to learn and understand.

1. The raceway is worn

The relative sliding friction between the surfaces causes the metal of the working surface to wear out continuously and cause failure. Abrasion will cause an increase in the fit clearance and a change in the shape of the raceway surface, and it will also affect the lubricating function of the lubricant, causing the bearing to lose rotation accuracy or even fail to operate normally. Raceway wear is divided into normal wear and abnormal wear. Normal wear and tear is a process in which the gap gradually increases during the full life cycle to complete the task of the full life cycle. Abnormal wear has manufacturing problems, standard parts problems, grease problems and later maintenance problems. The first three problems are related to the slewing bearing manufacturer, and the fourth situation is the problem of the equipment user.

2, plastic deformation of raceway

Under the action of external force, the partial plastic flow or overall deformation of the surface of the part, such as the deformation of the raceway or the torsion and warpage of the cage, causes the failure of the slewing bearing to fail to work normally, which is called plastic deformation failure. This situation often occurs after a period of use. At this time, the high-hardness layer has been mostly worn out. After the load and friction are suddenly increased, the metal inside and outside the raceway is squeezed into a pile. The steel with high hardenability should be used instead.

Slewing ring

3, the surface of the raceway peels off

The main reason for the surface spalling of the slewing bearing raceway is that the hardened layer is too thin and the hardness transition zone is too narrow. There are many reasons for contact fatigue failure. It may be that excessive axial load, poor lubrication, poor alignment, excessive impact load during installation, etc. can cause contact fatigue failure of the bearing. A lower frequency intermediate frequency equipment should be used to deepen the hardened layer. At the same time, it is necessary to appropriately increase the quenching and tempering hardness to reduce the hardness gradient of the raceway section.

4, raceway corrosion and pitting

The metal surface undergoes a chemical or electrochemical reaction with the environmental medium, and the surface damage caused is called corrosion failure. Corrosion is divided into three categories: chemical corrosion, electric corrosion, and fretting corrosion, which is mainly manifested as the corrosion of the internal bearing surface. Factors such as the intrusion of corrosive media, the condensation of moisture in the air, the sparks generated when the current passes, and the fretting vibrations can all cause corrosion failure of the slewing ring raceway. Pitting corrosion mainly occurs on the raceway treated by quenching and tempering. The reason is low hardness and unreasonable design of the raceway structure, causing sliding friction and contact fatigue stress, causing defects such as pitting corrosion and indentation.

The above is an introduction to the four forms of common slewing ring failures. In order to avoid such failures, reasonable and effective maintenance of the slewing ring should be carried out on a regular basis. This will not only reduce the occurrence of failures, but also increase the number of slewing rings. Service life.