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

/分类： /作者：

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

/分类： /作者：

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

Analysis of characteristics and machining difficulties of segmented ring gear

/分类： /作者：

The processing technic requirements of segmented ring gear is very strict. There are several important features: segmentation, high requirements for tooth accuracy, tooth quenching, precise locating stop requirements, etc.

It usually adopts high-quality 42CrMo material during processing. After quenching and tempering treatment, the material stability is improved. At the same time, the technic of coarse tooth opening and fine tooth shaping is adopted to reduce machining stress. Repeated tempering stabilizes and eliminates internal stress. After the gear ring is cut off, according to the deformation size, different correction methods are used to ensure the subsequent grinding machining allowance.

In order to reach the high precision of the teeth, the gear teeth grinding must be carried out. At the same time, it is necessary to ensure the run out of the positioning stop relative to the pitch circle. Because it is a segmented tooth, it needs to ensure each tooth can be ground, but also the grinding amount is as small as possible to avoid excessive grinding away of the quenched layer. It requires the roundness of the spliced ​​ring gear is particularly good, and the slit is uniform. To achieve the above requirements, it requires locating stop alignments for gear grinding. The gear grinding accuracy is synchronized with the accuracy of the outer circle alignment belt (installation reference), which can improve the assembly accuracy and efficiency and avoid the loss of gear accuracy caused by indirect alignment of the pitch circle during installation. And then ensure the installation accuracy of the large ring gear effectively.

 

Analysis of the difficulties in processing segmented ring gears:

 

1. Gear accuracy guarantee, common normal line length, tooth jump, gear roughness, tooth direction and tooth profile.

 

2. Gear deformation is difficult to control, expansion deformation, warping deformation, and parameters after gear segmentation are not under control

 

3. The processing of segmented gears, tooth processing, tooth surface quenching, and gear grinding, all need to be processed after fixed on the mold.

 

4. Make sure to prevent deformation in process plan of before heat treatment, after heat treatment, tooth processing, and segmentation. This is the top priority of this process. Many factories cannot meet the quality requirements after processing or during processing. Most of the indicators are out of tolerance and have to be scrapped.

 

During the processing technology of the segmented ring gear and budget, ensure that the processing is always under control and the processing procedures are complete. It is prohibited to segment directly after the gear is processed. Otherwise, the gear parameters, gear expansion deformation, and warpage deformation cannot be guaranteed.

 

Through the optimization of the processing technology and the design and application of special tooling, minimizes the precision error caused by the transfer of the reference surface during the finishing of the large gear ring and the processing accuracy of the various procedures of the ring gear is retained to the limit.

Luoyang Heng guan Bearing Technology CO.,LTD is a professional slewing bearing integrated entity enterprise integrating design, research and development, production, sales and service. We mainly engaged in slewing bearings and various high-precision slewing rings and large thrust ball bearings , Non-standard shaped bearings and other products. In addition, focusing on customer needs, we implement personalized optimization design and customized flexible production. Welcome to contact us for more details.

How to installation slewing bearing soft belt

/分类： /作者：

The right way to installation slewing bearing soft belt

The raceway of the slewing bearing device generally needs to be heat-treated, and the usual processes are: forging, roughing, quenching and tempering, finishing, smoothing, surface quenching of the raceway surface, and grinding of the raceway surface. The surface of the raceway surface is quenched to form a soft band. The so-called soft belt is an area that has not been heat treated. The formation of the flexible tape is necessary for the heat treatment process. In the final heat treatment process, due to the relatively large diameter of the raceway circle of the slewing ring, flame surface quenching is usually adopted by heating the surface of the workpiece to be hardened by acetylene and then adding water to cool, which is continuously performed. The heated flame spray gun and the water gun are mounted together while making a circular motion along the circle of the workpiece. Stop heating and spray immediately when moving to near 360 degrees. That is, the circular areas of heating and water spraying do not overlap. If there is an overlap in the circular area where heating and water spray occurs (heat treatment on the circle is greater than 360 degrees), cracking of the workpiece occurs. The tangential width of the unheat treated area is typically 15 mm. This 15 mm area is referred to as a soft belt in the slewing ring. It is often SoftZone in English. Under normal circumstances, the steel plate “S” is placed on the position where the soft belt is present in the workpiece to illustrate the specific soft belt position. Imported or domestically produced regular products usually have this very important mark. The position requirement of the flexible belt installation is essentially to improve the life of the bearing. From the perspective of the user and the manufacturer, it is better to install the position of the upper and lower loops of the slewing ring. Therefore, the manufacturer of the slewing bearing should accurately mark the position of the slewing ring, as the manufacturer and installer should properly install the slewing ring position as needed.

Because of the inevitability of the flexible belt on the slewing bearing device, it is required that the user who uses and selects the slewing bearing device should properly install the position of the soft belt to improve the service life of the bearing. The general principle is to try to install the flexible belt in the position where the soft belt carries the least pressure during the load change. Usually, the upper ring flexible belt of the slewing device is installed at a position perpendicular to the projection line of the pitch rotation surface. For example, the upper ring soft belt of the ship loader or the stacker reclaimer is installed at a position perpendicular to the center line of the cantilever and cut through the center of rotation. , that is, standing at the 90 degree position on the left or right side of the cantilever above the center of rotation. In the usual mechanical design, the flexible belt does not have the maximum state of force of the support rollers of the slewing bearing at this position. The installation position of the lower ring flexible belt of the slewing device is determined according to the center of gravity of the device and the range of the angle of rotation. If the angle of rotation is 100 degrees to the left and right, the maximum center of gravity of the upper part of the swivel is at the front. It is recommended to install the lower ring soft belt at the rear, that is, 180 degrees. If the position of the center of gravity change of the upper part of the swivel is equal in the front and rear positions, the angular position of the lower loop soft belt can be arbitrarily installed

Analyze the oil resistance of the slewing bearing seal material　

/分类： /作者：

In all kinds of large-scale machinery and equipment, especially those with rotating, conveying, and transportation mechanical ,there all need the slewing bearings.Due to the influence of the working environment, the slewing bearing has a sealing ring part,It is the main condition to ensure the sealing operation,It not only effectively prevents the intrusion of foreign dust and dirty grease, but also keeps the lubricating grease inside the bearing from being lost during use, and ensures that the bearing is in a lubricated state,in many cases, the sealing ring needs to be used in various oily media. The oil resistance is an important parameter of the sealing ring gasket, but the oil resistance of various sealing materials is also different.let us talk about the oil resistance of the slewing bearing seal material.

The commonly used materials for the slewing bearing seal ring : nitrile rubber, polypropylene rubber, silicone rubber, fluorine rubber, polyurethane rubber, etc.

1.Nitrile rubber

Nitrile rubber seal is a highly saturated elastomer obtained by special hydrogenation of nitrile rubber
Nitrile rubber is a commonly used material for mineral oil-resistant rubber seals
The mineral oil resistance of nitrile nitrate increases with the increase of acrylonitrile content
Hydrogenated nitrile rubber has good oil resistance(Good resistance to fuel oil, lubricating oil and aromatic solvents)
And because of its highly saturated structure, it has good heat resistance(-60 to 180 degrees).
Excellent chemical resistance(Good resistance to Freon, acid and alkali)
Excellent ozone resistance, high compression resistance and long deformation performance
Suitable for use in oil system hydraulic oil glycol system hydraulic oil diester series lubricating oil gasoline water silicon grease silicon oil and other media
Therefore, it is selected as the material of the slewing bearing sealing rubber ring, and continuous improvement is made from the material and technology to provide an additional layer of protection for the application performance of the bearing.

2.Polypropylene rubber

Polypropylene rubber seal ring has excellent heat resistance and oil resistance, applicable temperature (-30 to 170 degrees) the price is relatively cheap among high-temperature materials, but the disadvantage is that the cold resistance is slightly worse.

3. Silicone rubber

Silicone rubber sealing ring has high heat resistance and cold resistance; in addition to compressive strain, it has poor mechanical properties; pay attention to the swelling problem of low aniline point mineral oil and silicone lubricant

4.fluororubber

It has high heat resistance, oil resistance and excellent high temperature resistance.

5.Polyurethane rubber

The aging resistance, ozone resistance, and oil resistance are also quite good.

The above is the introduction of the oil resistance of the slewing bearing seal material,Since the material of the sealing ring is mostly soft material, that is, rubber, and it is oil-resistant, it is not only easy to use, but also can effectively ensure the sealing effect and ensure the high quality of the bearing operation.

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

/分类： , , /作者：

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.