Four-Point Contact Ball Slewing Bearing

1.Four-Point Contact Ball Slewing Bearing

The slewing bearing and the slewing bearing are similar in form, but there are qualitative differences. In short, the four-point contact ball slewing bearing is just a purely mechanical mechanism that can rotate.

The slewing bearing should realize various loads, precision and measurement and control, as well as realize the driving rotation of various actions.
Features in the field of use of slewing bearings:

◎Port cranes usually use three-row roller slewing bearings with internal teeth or external teeth with a diameter of 4 meters to withstand high overturning moments.

◎Stacker and reclaimer: The turntable bearings used in the stacker and reclaimer are usually ball-column combination type, three-row roller type and cross-roller type, and most of them have a diameter of

over 3 meters. Due to the harsh working environment and large dust, this type of bearing has the characteristics of high bearing capacity, long life and good sealing performance.

◎Ferris wheel: used for the four-point contact ball turntable bearing on the Ferris wheel, the outer diameter is 5000mm larger, and the thickness is 200mm

◎Ship unloader: The slewing bearing for ship unloader usually adopts the structure of three rows of rollers with external teeth, with a diameter of about 4 meters.

◎Tower crane: The slewing bearing used for tower crane usually adopts small-sized four-point contact ball slewing bearing or double-row ball slewing, and the diameter does not exceed 2 meters.

◎Radar antenna: The short-wave antenna generally uses a slewing bearing with a three-row roller structure, and the rotation speed is slow.

◎Shield machine: The diameter of the slewing bearing for shield machine ranges from 2.5 meters to 6 meters, and some have larger diameters. These bearings work under very harsh conditions, with large bearing load, strong corrosion resistance and short life. .

◎Ladle turntable: The slewing bearing for the ladle turntable usually adopts a three-row roller structure. Due to the harsh conditions with dust and high temperature, it has high requirements on the retainer, grease and sealing strip.

four-point contact ball slewing bearing Alt.

2.Emergency measures after the failure of the four-point contact ball slewing bearing

The large turntable four-point contact ball slewing bearing plays a very critical and irreplaceable role in bucket turbine bearings, stacker and reclaimer bearings, large ladle bearings and logistics transportation.

When the service life of the large bearing exceeds 5-8 years, and the large bearing of the ladle fails to stop, or cannot rotate in the forward and reverse directions, then the economic loss will be very huge, such as the large bearing of the bucket turbine of the thermal power plant, and the large bearing of the ladle, one day The loss is immeasurable.

First, remove the interfering parts that affect the normal rotation of the four-point contact ball slewing bearing
Second, remove the seal
Again, clean along the bearing gap with kerosene
Then, add rare grease
Afterwards, try rotating in the forward and reverse directions
Then, observe whether the bearing force is balanced, adjust the bearing load and balance
Next, remove the foreign matter overflowing from the bearing grease
Next, observe the gear meshing of the bearing to see if the tooth surface meshing is normal
Subsequently, if conditions permit, the use angle of the bearing can be exchanged
Finally, observe the condition of the bearing at any time, communicate with the manufacturer in time, guide the on-site installation of the new bearing, and strictly control the time and node for the installation of the bearing.

3.What are the quality standards for large bearings of four-point contact ball slewing ring

1. Material

2. Heat treatment

3. Clearance, runout, tooth jump

4. Comprehensive indicators, roughness, grinding, depth of hardness layer, flaw detection

5. The reference life value of similar bearing operation

The quality inspection of four-point contact ball slewing bearings can be divided into axial clearance and radial clearance according to different detection methods. important items to check. From the perspective of bearing application, clearance is an important indicator for detection.

Whether the bearing can obtain more satisfactory performance largely determines its radial clearance.
The specific tests are as follows: the high-frequency quenching hardness of the four-point contact ball slewing bearing surface should not be lower than 55HRC, the depth of the hardened layer should not be lower than 4mm, and the width of the soft belt should not be lower than 50mm.

There are certain requirements for the quenching time and temperature of the support bearing for tempering processing. In general, it needs to be quenched at a temperature of 200 degrees, so as to ensure that the stress is completely eliminated.

In addition, the most important thing is grinding. It is necessary to select a suitable grinding wheel to complete the grinding, and strictly control the linear speed to avoid raceway burns. Then for fine grinding, it is necessary to choose a resin grinding wheel with a particle size of 46° or 60° for grinding. For the support bearing containing gears, the gear hobbing process is required after the grinding process. The requirements for the entire process are very strict, and the accuracy must exceed grade 8.

China Factory Best Four-Point Contact Ball Slewing Bearing

1.Why do high-speed bearings choose the four-point contact ball slewing bearing?

Why do high-speed four point contact ball slewing bearings choose the four-point contact ball structure? Why do high-speed bearings choose the four-point contact ball structure? This article analyzes the reasons one by one, and provides some theoretical and practical basis for selection, design and application.

First of all, select the slewing bearing, which is positioned at a high speed, at least above 30rpm, generally more than 10rpm, and the four-point contact ball bearing structure is preferred. Secondly, because the ball bearing and the raceway are in four-point contact ball slewing bearing, which is a point contact, during the movement of the contact point, when the two circles are theoretically absolutely parallel up and down, the flexibility is far more than that of the crossed roller and the three-row ball structure.

The latter is usually a line contact motion process and can be understood as a surface contact. Again, ball bearings can use PTFE cage and copper cage to increase the speed, 60-120rpm. Of course, due to the structure, noise and vibration will occur at extreme high speeds, usually by grinding the grooves and improving the accuracy to the greatest extent possible to reduce the index.

four-point contact ball slewing bearing Alt.

The structure of the four-point contact ball slewing bearing determines the characteristics of high speed, wear resistance and long life. The structure of the four-point contact ball slewing bearing determines the characteristics of high speed, wear resistance and long life.

Carefully check the channel of the four-point contact ball slewing bearing, the contact point between the steel ball and the channel, and the inner and outer rings are in contact with two points, so it is called a four-point contact ball bearing. Double-row ball bearings are double-row arc grooves.

For the same reason, they are also called eight-point contact ball bearings. Flexible, not easily subject to various errors, it is flexible, easy to install, easy to maintain, and has the best feedback from use. Therefore, compared with the crossed roller bearing and the three-row ball bearing, the rotational speed can be appropriately increased, and the rotational speed can be as high as 70-120rpm when combined with the PTFE cage.

2.What are the matters needing attention in the installation of slewing bearing?

First of all, compared with other parts, the four-point contact slewing bearing is the core of the rotating part and belongs to the precision product. Therefore, it is necessary to understand the installation precautions of the slewing bearing:
1. After understanding the rotation accuracy of the slewing bearing, first ensure that the installation base is flat. Remember, it is very important, the base is not flat, and the hidden danger is great.

2. Whether the force and eccentric load of the bearing are within the theoretical calculation

3. According to whether the bolts are installed or not, pre-tighten them into 180° one by one.

4. Whether the S soft belt area is in the non-load area, that is, the area where the force is not often or the weakest force, taking the crane as an example, the bearing should be installed in the area where the cantilever direction is vertical

5. After the gear meshing rotates in the forward and reverse directions, no other abnormal noises can be gnawed.

6. There is a slight noise after the new bearing is installed. After fully refueling, the forward and reverse rotation still cannot eliminate the abnormal noise.

7. The positioning size of the bearing

8. The size of the mouth of the bearing

9. The seal of the bearing must not be interfered with by foreign objects, otherwise the sealing strip will be damaged

10. There should be no interference in the position of the dust baffle

What factors will cause the installation of the slewing bearing to be unsmooth or even unable to rotate? Taking the following factors into consideration,

1. Mounting holes. The threaded hole of the mounting hole is not standardized, the threading is not complete, and the threading is defective, so that the bolt cannot be screwed in.

2. The center diameter and chord length of the mounting hole exceed the tolerance too much, such as 3-5mm, so that the bolt cannot be pierced

3. The size of the positioning hole and the step is too large and cannot be matched

4. The bearing after heavy load has a rotating dead center or an ellipse, which causes it to fail to operate normally.

5. The bearing is not in the installation direction of the installation design drawing, resulting in the opposite direction of the taper pin, which has potential safety hazards

6. The installation part interferes, such as tooth top interference, there is a phenomenon of gnawing teeth, and some parts conflict with each other

7. The design of negative clearance is unreasonable, resulting in the phenomenon of inclined force, partial load and clearance after installation

8. The design of the equipment structure is unreasonable, which leads to the failure of normal debugging.

Slewing Ring Bearing Manufacturers

The Installation and Maintenance of Slewing Ring Bearing

The structure of slewing ring bearing

slewing ring bearing Alt.

Preparation

1) Make sure that the model is the same with the contract.

2) Make sure the slewing bearing is not damaged during the transportation.

3) Open the package in clean and dry environment.

4) The Bracket should have enough flexility to avoid the distortion of the slewing bearing and influence of its usage.

5)The installation datum plane and bracket installing plane should be clean,grease,burr,paint and other foreign bodys should be wiped off.

Installation

1) The screws in the installing plane should fit with the mounting holes in the slewing bearing.

2) Slewing RIng Bearing ball track quencher soft zone(lies between the exterior mark”S” and the jam.) is in the non-loading zone or non-regularity loading zone.Upper and lower rolling ring “s” soft zone should stagger for 180 degree. The soft zones of crane and excavator machinery should be in the place which forms a 90 degree angle with the arm support direction( the maximum load direction).

3) Put the slewing ring bearing on the bracket and check the contaction condition between the supporting plane and bracket with feeler gauge, level up with pad mat if clearance appeared, so as to avoid distortion after screwing down, and affect the performance of slewing bearing.

4) Before screwing down, adjust gear side clearance by gear circle radial runout vertex (3 green symbols gears), after screwing down, check gear side clearance in all the gear rings.

5) Install slewing ring bearing with high strength Screws, and choose appropriate strength bolts by stress condition, screw down in 180 degree direction, and check all bolts to ensure that every one in the circle has the same pretightening force, not spring washer but hardening plain steel washer should be choosed in installation, screw down bolts in turn by the picture below:

6) After installation, you should wife off the dust and dunghill in the slewing ring bearing and paint some antirust paiting,also paint some lubricate grease in raceway and gear.

Operation,Maintenance and Lubrication

1) Before the slewing ring bearings leave factory ,some No.2 EP grease (GB7324-1994) should be in slewing bearing raceway, change it into new lubricate grease according to your different working conditions.

Add grease regularly in slewing ring bearing raceway. Ball slewing ring bearing is lubricated every 100 hours, roller slewing bearing is lubricated every 50 hours, shorten the lubricate period in specially working condition, for example: in torrid zone, with high humidity, more dust, fast changing temperature and working continuously.

Add enough grease before and after the the machine’s long-term stop. Fill the raceway with grease till it is seeping from the seals.turn slewing bearing slowly when you add grease to make the grease equally filling.

2) Usually wipe off the foreign bodys and spread grease.

3) Check the pretightening force of the blot after the slewing ring bearing running first 100 hours, then make sure enough pretightening force every another 500 hours.

4) Give your attention to the running slewing ring bearing, you should stop it to check when noises, impulsion, abrupt accretion power appeared, and dismantle it to check when necessary.

5) Its better to protect the slewing ring bearings from dust, rain,water and high tempreture in operation, and defend gear engagement zone against hard objects.

6) Check the seal usually, change it when it is damaged,reset it when it is breaking off.

Commonly used lubricants have been list in the following table,Often lubricate the reverse with gear grease

Bearing Structure	Working Condition		Lubricated Parts	Lubricant
Bearing Structure	Working Condition		Lubricated Parts	Product	Quality Marker	Standard
Plastic insulation rubber ring seal	Low and normal temperature,moist -20℃ + 60℃		Ball Track	Extreme pressure lithium lubricating grease	No.1 No. 2	GB7323-1994
Plastic insulation rubber ring seal	Low and normal temperature,moist -20℃ + 60℃		Geared wheel	Black Lead Radical Lubrication	ZG-S	SH/T0369-1992
Metal Insulation Iabyrinth packing	High Temperature, moist	40°C ～120°C	Ball Track	Extreme pressure lithium lubricating grease	No.1 No.2	GB7323-1994
			Ball Track	M0S2 Compound calcium radical lubricating grease	No.2
			Geared wheel	No.4 high temperature lubricating grease	No.4	SH0376-1992
		80°～180°C	Ball Track	M0S2 Compound calcium radical lubricating grease	No.2
		80°～180°C	Geared wheel	No.4 high temperature lubricating grease	No.4	SH0376-1992
	Normal temperature, resistance to sea～60°C		Ball Track	No.2 Compound aluminum radical lubricating grease	No.2
	Normal temperature, resistance to sea～60°C		Geared wheel	No.4 aluminum radical lubricating grease	No.4	SH0378-1992

Preservation

The slewing ring bearing has been sealed with oil before it leaves the factory. The packed slewing ring bearing at optimal conditions can be stored for 6 months. Idle ball tracks need lubricating every 2 months.(please refer to “Maintance and Lubricating”).Idle slewing bearing needs oil sealed packaging every 6 months.

Oil Sealed Packaging:

1) Take out the slewing bearing from the wood box.

2) When removing the wrapping, do not rip the sealing tape, remove the wrapping from the outside to the inside.

3) After taking the slewing bearing into pieces, infuse the ball track with lubricating grease.First deoil the surface and then do oil sealed packaging.

4) When deoiling, do not infuse solvent containing chlorie into sealing band and the ball track.

5) After deoiling, clean down the out surface, plaster the preservative oil and grease(F20-1) or industrial petroleum jelly(SY1607-77)evenly.

6) Then ,pack it as it was primarily done.Encase it again in the wood box.It is better to batter down a asphalt felt in the box to protect against moisture and rain.If there is no box to store the bearing, after oil sealed packaging, store it in folds.

Best China Small Slewing Bearing

1.Why does the slewing bearing get stuck and have a dead point with no load and normal rotation load?

The no-load bearing can rotate normally, and the clearance, warpage, ellipse, and groove shape are directly related to the contact point.

Especially after the load, the contact point of the channel and the shape of the channel are very critical and very obvious. If it rotates before no-load, it is because there is enough clearance to affect the rotation, but after the slewing bearing is stressed, the contact point theoretically moves in a circle along the parallel trajectory of the upper and lower contact points of the bearing.

In fact, the shape of the channel is warped. Curve and ellipse, at this time, the contact point is jumping and irregular, which is equivalent to the jumping and turning of the steel ball ups and downs, so that it enters an infinite loop, resulting in stuck.

Generally speaking, the slewing bearing in the crane bearing, crane bearing, bucket turbine bearing, fixed crane slewing bearing, stacker-reclaimer bearing and crane bearing and other large marine crane bearings, the failure occurred in the early stage, according to the failure level Basically divided into three categories

The failure of the large bearing was initially manifested because of the sound and abnormal sound. Eliminate interference, such as rotation interference, gear interference, good dust baffles, etc. The reasons for the noise are mostly abnormal load, ball impact sound, uneven contact between the channel and rolling elements, deformation, etc.

If it is a new slewing bearing, it means the channel There are ovals or warping, and stress relief is not complete. It is a manufacturing defect. If possible, the bearing should be disassembled and the groove fitting should be re-ground.

If it is sharp and harsh, accompanied by vibration, swing, or jitter after the abnormal noise, it means that the slewing bearing has penetrated into the core of the fault, the rolling elements are broken, the channel is strained, and even the hardness layer falls off. At this time, the bearing has repair value.

If the equipment has a spare bearing, it should be replaced in advance. The old bearing is disassembled and repaired, and the service life can reach more than 80% of the new bearing. In fact, many spare bearings are used as new bearings for emergency use.

If there is no spare bearing, on the basis of confirming the drawings and model, strengthen the maintenance and maintenance of the old bearing, and start the customization of the new bearing, which generally takes 60-80 days.

Bearing rotation begins to be difficult, stuck, stuck or even stuck. Basically, it is announced that the bearing has fallen into the nest. At this time, it can only be pulled hard, cleaned with kerosene, or rotated back and forth. It is the factory that has to work three shifts and pay three times and four times the cost to manufacture it in a short time.

slewing bearing Alt

2.Four-point contact ball bearings and crossed roller bearings

Comparison of working conditions and selection and positioning of four-point contact ball bearings and crossed roller bearings. Simply speaking, it is very important to choose a four-point ball bearing or a crossed roller bearing according to the needs of the working conditions.

In terms of precision design, crossed roller bearings are more obtainable, and in terms of rotational flexibility, four-point contact ball bearings are better.

In the accuracy level, when the speed is higher than 10rpm, and there are certain requirements for noise, such as when the requirement is less than 80 decibels, the four-point contact ball is the first choice, and the PTFE cage or copper cage is selected.

In terms of rigidity and stability, crossed roller bearings are the preferred choice, but the rotational speed should be low, generally below 8rpm. And since the cross rollers are arranged in a 1:1 ratio, noise is unavoidable when reaching high speeds, because the friction and impact of the rollers are unavoidable.

At the same time, we must pay attention to the use of lubricating oil, and grease is indispensable. Gear grinding, groove grinding, high-precision steel balls, deep groove ball grooves on the inner ring, four-point contact ball grooves on the outer ring, and two-point contact are also ways to reduce noise.

Cheap Price OEM Manufacturer Slewing Bearing

The design and selection of slewing bearing

The design and selection of slewing bearing and the consideration of key parameters, one is the rotation accuracy; the second is the realization of the bearing capacity; the third is the matching degree of the working conditions.

The fourth is the comprehensive consideration of design and selection, which is convenient, fast, safe and reliable.
Rotary slewing bearings have unique load-bearing characteristics and are commonly used on devices such as hoisting machinery, excavators, turntables, wind turbines, telescopes, and tank turrets.

Through the improvement of machining methods and the upgrade of design, the current slewing bearing can be applied to smaller, more complex and more precise occasions.

The correct selection of a slewing plate bearing depends on requirements such as load, stiffness, rotational speed, size and rotational flexibility. Design goals and bearing suitability are jointly selected by the customer and the manufacturer to help optimize system performance at the lowest cost and guaranteed trouble-free operation.

Usually the load capacity is the decisive factor in selecting the bearing section size and diameter, but other parameters determine which bearing type is best to choose.
1. If there is a large torque requirement, it is generally necessary to use double-row four-point contact ball bearings.
2. Increasing the stiffness generally requires the use of roller bearings.
3. The maximum load bearing requires the use of crossed rollers (two-row or three-row roller bearings)
For applications requiring increased rigidity and load bearing, large size bearings are required, but for applications with sensitivity requirements such as robots and manipulators, small size bearings are required.

The slewing bearing with smaller inner diameter makes the structure of the mounting member more compact and the total weight is reduced. At the same time, for the occasions with high rotation speed and small structural deformation, it also reduces the moment of inertia.

slewing bearing Alt.

2.The influence of the structure of the slewing bearing on the selection design, cost and life

Slewing bearing is a special structural bearing that can bear large axial load, radial load and overturning moment at the same time. – Under normal circumstances, the slewing bearing itself has mounting holes, lubricating oil holes, sealing devices, and gears, which can meet the requirements of the working host under various working conditions; on the other hand, the slewing bearing itself has a compact structure and is easy to guide and rotate. ,

Easy installation, easy maintenance and other characteristics, so it is widely used in mining, mining, construction, port, medical and other aspects. The structure of the slewing bearing has a decisive influence on the selection. The four-point ball is the best in flexibility and fatigue resistance.

The double-row ball bearing is the first choice for marine bearings and crane bearings, automobile crane bearings and cement pump bearings; cross Roller bearings are often used for precision, measurement and control and positioning, and the speed is low. Three-row roller bearings are typical low-speed heavy-duty bearings.

The single-row four-point contact ball slewing bearing is composed of four parts: inner ring, outer ring, steel ball, and spacer block. It has a compact structure and light weight. radial force. Construction machinery such as rotary conveyor, welding manipulator, small and medium-sized crane and excavator can be selected.

The double-row ball slewing bearing has three races, and 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, and the bearing angle of the upper and lower arc raceways is 90°, which can bear a large axial force and tipping 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 bearing 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 or larger diameters.

The single-row cross-roller slewing bearing consists of two races, with compact structure, light weight, high manufacturing precision, small assembly clearance, and high requirements for installation accuracy. Force, tipping moment and larger radial force are widely used in lifting and transportation, construction machinery and military products.

Three-row roller slewing bearings have three races with separate upper and lower and radial raceways, so that the load on each row of rollers can be determined exactly. It can bear various loads at the same time, and is the one with the largest bearing capacity among the four products.

The shaft and radial dimensions are large and the structure is firm. It is especially suitable for heavy machinery requiring large diameters, such as bucket wheel excavators, wheel Cranes, marine cranes, port cranes, molten steel running table and large tonnage truck cranes and other machinery.

China Best Tower Crane Slewing RIng Bearing

1.Tower Crane Slewing Ring Bearing

Underwater slewing bearing and slewing bearing, the process is very complex, the manufacturing cost is high, there are many high-precision and high-precision matching dimensions, the theoretical design life is long, and the reliability and stability requirements match the overall design life. In addition, waterproof seals and special materials are used. core process indicators.

As shown in the figure in terms of precision design and manufacturing process,

Using four-point contact ball bearings and double-row ball bearings, the theoretical design and 3D diagrams are shown as follows:

tower crane slewing ring bearing Alt

The structure of the channel, the contour shape and the ideal state of the contact points are shown in the figure. The channel of the double-row ball bearing has eight contact points, and the actual machining accuracy is required to be higher.

At this time, the level of CNC machine tools and operators is extremely important, which determines the high precision level of the entire bearing.

Waterproof sealing is absolutely the core process and key technical index of the entire tower cranes slewing ring bearing. The sealing adopts three sealing strips, and the sealing contact part adopts ceramic technology to enhance air tightness, improve lubrication protection and wear resistance, fatigue resistance, corrosion resistance and rust resistance. .

The two O-rings are the highlight of the design, which once again achieves airtightness in the first-line protection, making the waterproof seal worthy of the name and achieving the patent of beautiful utility model.

2.Selection, maintenance and replacement of slewing bearing of port gantry crane

As the core component of the port gantry crane, tower cranes slewing ring bearing should be reasonably selected, installed and used correctly, effectively prevent and maintain faults, prolong the service life of the slewing bearing, improve the safety of equipment use, and increase economic benefits.

The slewing bearing is the core component of the port gantry crane (hereinafter referred to as “gantry crane”), which can bear the combined loads such as axial load, radial load and overturning moment at the same time.

Due to the complex load, difficult replacement, and high maintenance costs, the door crane is generally selected according to the 20-year design service life, but it is often not guaranteed in actual use.

In recent years, large-tonnage gantry tower crane slewing ring bearing in various coastal ports have successively suffered slewing bearing failures, causing huge economic losses to enterprises. Therefore, it is particularly important to effectively select, install, use, maintain and extend the service life of the slewing bearing.

Reasonable selection of slewing bearing

The utilization level of the port door crane is U8, the load state is Q4, and the working level is A8. It has the characteristics of high utilization rate, large load bearing, fast running speed and high working level.

According to the tower crane slewing ring bearing load and life calculation method, the static load safety factor fs of the grab gantry crane is 1.45, the life load factor fe is 1.7, and the service life Lf during full rotation is 150,000 revolutions. However, the actual operating rotation range of the iJ machine is mostly within 180° left and right of the sea side.

The high-strength reciprocating operation and the combined load will aggravate the fatigue of the bearing within a certain range. Therefore, the selection and installation of the slewing bearing has strict requirements. requirements.

At present, the structural forms widely used as tower cranes slewing ring bearing mainly include four-point contact ball slewing bearings, double-row reducing ball slewing bearings, crossed cylindrical roller slewing bearings and three-row cylindrical roller combined tower cranes slewing ring bearing.

Generally, when the bearing rotation diameter and section size are basically the same, the static and dynamic load carrying capacity of the three-row cylindrical roller combination slewing bearing is the largest, which reduces the load of each roller compared with the crossed cylindrical roller slewing bearing.

Compared with the double-row reducing ball slewing bearing, the load is changed from point contact to line contact, which reduces the contact stress. According to the working conditions of port gantry cranes, the structure of this bearing is most suitable for the use requirements of port gantry cranes.

Correct installation of tower cranes slewing ring bearing

As a large thin-walled ring component, the tower cranes slewing ring bearing must be rigidly connected with the gantry cylinder and the flange of the slewing plate. Warpage deformation occurs, so the flange must be machined to ensure accuracy.

Taking the 132.50.4500.03 type slewing bearing often used in 40T door cranes as an example, the diameter of the center circle of the rolling body is 4500mm, and the flatness of the flange plate is required to be 0.30mm at most, and this value is only allowed to appear in the range of 180 – – times, and A steady rise or fall without waves.

The inclination of the radial width is less than 0.25, and the surface roughness Ra reaches 3.2. At the same time, the flange should also have sufficient axial and radial stiffness to ensure that the deformation in the vertical and horizontal directions is within the specified limits.

Bucket Turbine Bearings

1.The common faults of bucket turbine bearings and their treatment measures are as follows:

1.There are noises and vibrations in the gear meshing, it should be stopped for maintenance, and the meshing state of the gears should be checked. You can use coloring powder to check the contact area of the tooth surface to confirm whether the meshing is normal.

2.If there is a sound inside the slewing bearing, you must add grease to multiple points and rotate in forward and reverse directions until the sound is reduced or disappeared.

3.The bucket turbine bearing eccentric load is serious, which can be corrected by adjusting the arm length and stowage of the bucket turbine.

4.The bucket turbine bearing has inner and outer ring clearance, and the rolling element of the large bucket turbine bearing is replaced by a professional maintenance team. The specification is 100*98.5mm.

5.Replace the sealing strip, the specification is 5*21mm

6.As the bucket turbine bearing for the power plant bucket turbine, the steel mill bucket turbine stacker and reclaimer slewing bearing, confirm the drawings and spare a set of large bucket turbine bearings for emergency needs

7.Common models of bucket wheel machines, 1797/2500G, 1797/2600; 1797/2635 and 1797/3230 series. bucket turbine bearing Alt

2.The acceptance inspection,maintenance and installation standards of bucket turbine bearings are mainly based on the following:

1. The acceptance data is subject to the drawing confirmation drawing.

2. The core data of detection include clearance, tooth jump and slewing bucket turbine bearing performance

3. The three main aspects of maintenance are tooth surface inspection, raceway inspection and rolling body inspection

4. The reference requirements for installing bucket wheel bucket turbine bearings are based on the installation technical requirements of the bucket turbine bearing, mainly for the installation base surface, bolt connection and rotating gear jump.

5. After the installation, replacement, maintenance and repair of the bucket wheel bucket turbine bearing, there is no abnormal noise, no vibration, no dead point, and no force settlement after the overhaul.

When replacing the large bucket turbine bearing bearing of the ladle and the bucket turbine bearing of the bucket wheel machine stacker and reclaimer, there is usually a problem of installation accuracy error.

For example, there is a situation where the mounting base is equipped with a drill, the fitting clearance of the mounting hole of the large bearing is too small, and the mounting base is deformed. displacement situation.

How to solve the problem of uneven installation of large bucket turbine bearings in a short time? The following are simple, practical and effective solutions.

1. Replace the next level mounting bolt specification. If M42 was originally used, M36 can be used for emergency, and M33 can be used instead of M36. The grade is not lower than 8.8 high-strength bolts.

2. Adjust the rotation direction of the bucket turbine bearing. Generally, if the deviation is not large, the bolts can be installed normally.

3. The aperture of individual mounting bases can be solved by reaming at a constant speed.

4. In extreme cases, the bucket turbine bearing should be reamed. Boring and milling machines can be used to expand the hole, and the mounting hole is generally expanded into an ellipse.

Regarding the design characteristics of the large bearing of the steel mill bucket turbine and the large bearing of the ladle, because of the special working conditions, at the beginning of the design, the large bearing is required to be able to withstand high load, high temperature, dust, safety, reliability and life.

Can exceed the design requirements of ordinary bearings. Technical details of slewing bearing, technical service of slewing bearing Yuan Gaogong, I5B–965B–OI9O.. Communication is efficient.

First of all, the design concept should emphasize heavy-duty bearings, so the inner and outer rings of the bearing should be strong and solid, the rolling elements should be large, the cage should be segmented or integral cage, and the material should be PA66 or steel cage.

Secondly, the choice of lubricating grease can use 2 lithium base grease, lubrication is extremely important. Multiple batches, multiple batches, to ensure lubrication from beginning to end.

Thirdly, lubrication protection, dust cover, and dust baffle can effectively prevent foreign objects from entering.

Finally, the material and hardness can be higher than the design manual, and the design cost is appropriately increased.

China Manufacturer High Quality Slewing Ring Bearing

How to correctly install and maintain the slewing ring bearing

The following describes the correct installation and maintenance methods for the slewing bearing (slewing bearing) from three aspects: transportation, storage, installation and maintenance:

I. Transportation and storage of slewing ring bearing

The slewing bearing (slewing ring bearing) has been coated with anti-rust oil before leaving the factory and wrapped with film and linen. The rust-proof period of this package is generally 3-6 months.

The storage temperature should be 20±10°C, and the relative humidity is not more than 60%. After the expiration date, it should be maintained in time. The slewing bearing stock should be filled with grease after one year and check the flexibility of its rotation.

The slewing ring bearing (slewing bearing) is usually fixed on the pallet or in the package when it leaves the factory. It is available in single-piece packaging and group packaging.

Transportation and storage should be kept level, can not be collided and squeezed, can not be rained, and the storage should be flat. There should be a flat separation between the stacked slewing bearings. The slewing ring bearing generally has a lifting hole, which can be screwed into the eyebolt for safe lifting.

slewing ring bearing Alt

Second, the installation of slewing ring bearing

First open the slewing ring bearing (slewing bearing) package, check the certificate and the sign, and confirm that the slewing bearing type used is correct. The installation steps are as follows:

A, the installation plane of slewing ring bearing

The mounting surface should be smooth and remove all excess material such as paint residue, solder beads, burrs, etc. When cleaning, be careful not to let the solvent penetrate into the inside of the slewing ring, and do not use solvents that damage the sealing material.

The mounting surface should be dry and free of lubricant before assembly. Measures to protect workers and the environment should be taken.

B, the rigidity of the support

Standard slewing bearings and zero-gap slewing bearings have different requirements for the rigidity of the bearings.

C, positioning of slewing ring bearing

The inner and outer ring raceways of the slewing ring have a soft belt and should be placed on both sides of the main load plane. That is, it is shifted by 90 degrees from the main load zone.

There is a blockage at the soft belt or an “S” mark. Also check the slewing bearing and the mounting surface, usually with a feeler gauge. If the fit is not good, fill it with a suitable material. Welding work on the support is prohibited after installation of the slewing ring bearing.

D, solid bolt

1, the choice of mounting bolts

The bolts and washers should be installed using the specified (size, quantity, strength rating, etc.). Also note: Do not use fully threaded bolts, do not use old bolts, nuts and washers, do not use open washers such as spring washers, etc.

2, the choice of bolt pre-tightening torque

The pre-tightening force of ordinary metric bolts is recommended to take 0.6-0.7 times the bolt yield strength. It is recommended that the bolts larger than M27 use hydraulic fastening devices, and the pre-tightening force should not exceed 85% of the yield strength.

3, fastening bolts

The slewing ring should be installed under no load conditions. Note: Apply a little oil to the thread of the bolt to ensure that the friction resistance is balanced. Do not use glue on the bolt lock. Pre-tightening bolts: The pre-tightening should be carried out in three steps. The three-step force is 30%, 80%, and 100%, respectively.

E, adjust the gear backlash of slewing ring bearing

When installing a toothed slewing ring, it is important to properly adjust the gear backlash. It can be measured with a feeler gauge at the highest point of the radial runout of the gear, or it can be pressed with lead 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 turn to confirm that there are no other tooth high jump points, and check the backlash false back gap after the slewing bearing is finally fixed. The highest point of the radial runout of the gear is marked in the groove with green paint.

F, first lubrication

1. Raceway lubrication To ensure sufficient lubrication, the grease specified in the drawings or the product manual should be refilled before initial use. Pay special attention to all the grease nozzles injecting the grease one by one, preferably by turning the slewing bearing while filling the oil until the grease is squeezed out of the seal.

2. Gear lubrication When the gear is lubricated, the tooth surface should be clean. It is recommended to brush the grease on the gear with a clean brush.

Third, regular inspection and maintenance of slewing ring bearing

Check the bolt preload torque for the first time using 100 working hours. If more than 10% of the bolts are loose, check again after the 200th working hour.

It will be inspected every 500 working hours in the future; the inspection interval should be shortened in harsh conditions.

After 2000 hours of cumulative operation of the equipment, if a bolt is found to be loose to less than 80% of the specified torque, the bolt and the adjacent two bolts are replaced. If 20% of the bolts are found to be loose to less than 80% of the specified torque, all bolts will be replaced.

After the equipment has been working for 14,000 hours, all the bolts will be replaced.

For equipment with a high speed of rotation 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.

Good China Manufacturer Standard And Custom Slewing Bearing

Anti-corrosion and wear-resistant coating on sealing contact surface for slewing bearing

For large-scale high-end slewing bearings, due to special working conditions, such as working in muddy water, river water or sea water, special treatment is required for the sealing contact surface.

As a rubber seal contact, typically softness overcomes rigidity, and the sealing contact surface is often worn into grooves, so that the sealing effect is large. discounted, thereby losing the sealing function.

Surfacing stainless steel, with the help of stainless steel’s characteristics of non-corrosion, high strength, high hardness and good wear resistance, when combined with the slewing bearing, the welding performance is poor, and the grinding effect is unsatisfactory.

Brass surfacing, as the metal properties of brass, confirm that the hardness is moderate, the surfacing welding is easy to combine, and it is easy to accept as a traditional solution, when compared with sprayed ceramics, and so on.

Spraying ceramic process (chromium trioxide), high strength, high bonding performance, best surface roughness grinding, because of the particularity of ceramics, contact with rubber seals, almost no loss of precision, the best effect in experiment and practical . slewing bearing Alt

NoWear coated slewing bearings

NoWear is a wear-resistant carbon coating that can be applied to the rolling elements and inner ring raceway(s) of a bearing (designation suffix L7DA) or only the rolling elements (designation suffix L5DA) (fig. 1).

A physical vapour deposition process applies the wear-resistant carbon coating. Thickness of the coating ranges from 1 to 3 μm, depending on the size of the bearing. The hardness of the coating is 1 200 HV10.

NoWear coated bearing surfaces retain the toughness of the underlying material while adopting the hardness, improved friction properties and wear-resistance of the coating.

During the running-in period, minute amounts of the coating material are transferred to the counter-surfaces. This coating reduces friction and improves resistance against wear and smearing, even in bearings where only the rolling elements are coated.

Functional impairment due to base metal corrosion for slewing bearing

Base metal corrosion (red rust formation) is the most common type of corrosion on steel materials and is caused by the simultaneous presence of moisture and oxygen. In the metalworking industry, rust formation primarily impairs the component function and operating life.
As a general rule, minor corrosion to the exterior of a fitted bearing does not have an adverse effect. Rust formation in the interior of the bearing is, however, critical in many respects.

Localised pitting corrosion on rolling surfaces generates stress peaks during overrolling, which can lead to premature fatigue. As in the case of false brinelling, rust particles have an abrasive effect and lead to wear. Lubricants and seals serve to protect the internal components of a bearing.

The applied protective coatings act as surface protection in the outer area of a bearing and thus prevent damage to the rotary shaft seals.

Innovative coating variants as key technology for slewing bearing

With its innovative coating variants, Schaeffler ensures that premature fatigue does not occur, thus enabling long-term function.By optimising process parameters and making further developments in plant technology, Schaeffler is providing an important and futureoriented key technology for the deposition of thin and uniformly distributed coatings.

In the area of corrosion protection, the protective coatings produced in this way bring about an improvement in general component characteristics and play a key role in optimising components.

The outstanding characteristics of the original thin film coating(electroplated zinc alloy system) have been continuously improved by the further development of this system and the establishment of new coating systems, and correspond to (or significantly exceed) the current level of technology.

As a globally established system supplier of automotive and industrial components,Schaeffler equips its products with added value through state-of-the-art technologies based on high-performance surface treatments.

Wholesales High Quality Slewing bearing Maintenance Update 2022

1.Slewing bearing maintenance and repair methods and matters needing attention

The mounting support of the slewing bearing maintenance must have sufficient rigidity and the mounting surface should be flat. Before assembling the slewing bearing, the slewing bearing maintenance should be treated with stress relief, and the slewing bearing maintenance and the slewing bearing should reduce the deformation of the slewing bearing. When assembling, the contact surface between the bearing and the slewing bearing must be cleaned.

slewing bearing maintenance Alt

2. Pay attention to the change of noise and the change of the slewing resistance torque during the use of the slewing bearing and the slewing bearing maintenance. If there is any abnormality in the slewing bearing maintenance and the slewing bearing, it should be dismantled and inspected.

3. The slewing bearing must be lifted or stored horizontally, and must not be lifted or stored vertically to avoid deformation.

4. Before the slewing bearing maintenance and slewing bearing are tightened, the meshing inspection of the gear should be carried out, and the meshing condition should meet the requirements of the gear accuracy:

that is, the contact spots distributed on the tooth surface of the gear pair after running under slight braking are on the wheel. Not less than 25% in the direction of tooth height and not less than 30% in the direction of tooth length.

5. The slewing bearing maintence and slewing bearing tooth surface should be cleaned for 10 shifts and re-applied with grease.

6. Slewing bearing maintence and slewing bearing In order to ensure the reliability of bolt operation and avoid insufficient bolt pre-tightening force, after 100 hours and 500 hours of slewing bearing maintence operation, both slewing bearing and slewing bearing should check the pre-tightening torque of bolts respectively. The preload torque should be checked every 1000 hours thereafter

7. The bolts and nuts connecting the slewing bearing are made of high-strength bolts and nuts; double nuts are used to fasten and prevent loosening.

8. When tightening the nut of the slewing bearing and the slewing bearing maintence, lubricating oil should be applied to the thread of the bolt and the surface of the nut, and the torque wrench should be used to tighten it symmetrically and evenly in the circumferential direction for many times.

The pre-tightening torque on each bolt should be approximately uniform when tightening the second pass.

9. Four oil cups are evenly distributed on the upper surface of the ring gear of the slewing bearing aligned with the raceway, thereby adding grease to the raceway. Under normal circumstances, the slewing bearing runs for 50 hours with lubrication times. You must add enough oil each time until grease seeps out of the seal.

2.slewing bearing maintence effect

1. During the use of the machine, we should add lubricating oil to the bearing in time, because the excessive operation of the bearing can easily lead to a large number of wear problems. Dropping lubricating oil every two to three hours can reduce this problem. friction damage.

2. The slewing bearing is a component with a high reimbursement rate in the whole machine, so when we buy the corresponding machine, we should pay attention to adding a few spare parts when purchasing the bearing, and the material of the spare bearing should also be selected well Otherwise, the bearing will be eliminated soon after use, or the performance of the machine will not be evaporated.

3. The machine should be cleaned every month. At this time, don’t pay attention to dismantling the bearing for cleaning, and clear the large amount of oil or other dirt attached to the bearing, so as to make the whole bearing work effectively. be improved.

In addition, it should be noted that after the slewing bearing has been running for 100 hours, the bolt pre-tightening force should be checked, and every 500 hours of operation in the future must maintain sufficient pre-tightening force.

In use, it is forbidden to directly wash the slewing bearing with water to prevent water from entering the raceway, and strictly prevent hard foreign objects from approaching or entering the tooth meshing area.

Check the integrity of the seal frequently. If the seal ring is found to be damaged, it should be replaced in time, and if it is found to fall off, it should be reset in time. During use, grease should be added regularly. Generally, ball slewing bearings are refueled every 100 hours, and roller slewing bearings are refueled every 50 hours.

In special working environments, such as high temperature, high humidity, and dust , When the temperature changes greatly and when working continuously, the lubrication cycle should be shortened.

When injecting grease, turn the turntable bearing slowly so that the grease is filled evenly. For slewing bearings with internal teeth or external teeth, debris should be removed frequently and the corresponding grease should be applied.

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