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Large Slewing Ring Bearing

1.Large Slewing Ring Bearing Quality

In short, if you have to distinguish from the selection, quality reliability and high standards of slewing ring bearings, you can refer to the following:

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 slewing ring bearing operation

The quality inspection of slewing bearing 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 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 slewing ring bearing for tempering processing. Under normal circumstances, it needs to be quenched at a temperature of 200 degrees, so as to ensure that the stress is completely eliminated.

The grinding amount cannot exceed the rough grinding process, and the finish must meet the requirements of the specified grade. For the support slewing ring bearing containing gears, the gear hobbing process is required after the grinding process. The requirements of the whole process are very strict, and the precision must exceed eight.

large slewing ring bearing Alt.

2.Maintenance of slewing ring bearing

The difference and connection between the maintenance and repair of heavy equipment bearings and the replacement of new bearings are not only related to the cost of slewing ring bearings, but also related to the value of slewing ring bearing maintenance, repair and repair.

In short, more maintenance on weekdays will double the lifespan. Repair will increase the expected life of the slewing ring bearing. Maintenance is equivalent to remanufacturing, and the lifespan of a new bearing is the same. Replacing a new bearing is based on the parameters and process of the old bearing. Manufacturing a new set of bearings is the most expensive.

Of course, as a manager of equipment procurement, maintenance and maintenance, it is very important to plan and plan the state of the bearing in advance, to ensure that each stage is controllable and to minimize losses. Also make sure that the device does not lie down.

Correct Installation And Service Life Of Slewing Bearing

1.Proportional relationship between correct installation of slewing bearing and service life

As a precision rotating core component, the slewing bearing, the clearance value, the end runout, the axial runout and the radial runout, are all calculated by the wire and the track. It is very important to ensure the correct and precise installation of the bearing. Affect the service life and use effect of the bearing.

The design life of normal bearings is 20 years, and the service life is 10 years. Under the condition of ensuring accurate installation, correct use, maintenance and maintenance, the service life is about 10-12 years, and the heavy-duty bearing is about 5-8 years.

slewing bearing Alt.

Notes on installation:

1. Ensure the rigidity and strength of the installation base surface, ensure that the stress is released completely, and the installation surface should be kept clean and the installation accuracy meets the relevant regulations.

2. Make sure that the mounting bolts are high-strength grade 10.9, the nuts are grade 10, the gaskets are quenched and tempered gaskets, the tolerances of the mounting holes of the bearings are within the normal range, and each joint surface should be cleaned to remove paint, iron filings, rust inhibitors, etc.

3. The seal is the lubrication system of the bearing. Check whether the seal is still in the correct position, and clean the fitting part of the mounting plane of the slewing bearing.

4. When connecting with high-strength bolts, pre-tighten the bolts: It should be pre-tightened in three steps, 30%, 80%, and 100%, respectively, to achieve the specified pre-tightening torque. In addition, check the fit of the slewing bearing and the mounting surface, usually with a feeler gauge. If the fit is not good, fill it with an appropriate material.

. It is strictly forbidden to weld the slewing bearing to avoid the deformation of the inner and outer rings, which will affect the normal use.

6. During installation, if the installation base surface is uneven, thin copper sheets can be prepared. If the installation plane is indeed installed, it should be considered to leave convex and concave shoulders or positioning blocks for radial positioning.

7. The tempering belts of the upper and lower raceways should be staggered by 180°. When installing crane and excavator turntable bearings, the tempering belt of the rolling ring should be placed at an angle of 90° with the direction of the boom, and the tempering belt of the rolling ring should be fixed. , should be placed in a location with less frequent work.

8. After the installation work, the raceways and gears should be filled with grease and regularly maintained.

9. Make sure that the gear meshing reaches 70% and the force is even.

2.Processing skills of precision slewing bearing

High-precision slewing bearing slewing bearings, especially emphasized, low height, thin wall thickness, many processes, and high precision requirements, such as heat treatment, tooth processing, drilling processes, all have an impact on the overall machining accuracy and quality control of the bearing, so what can be done? Woolen cloth?

In order to ensure both quality control and parameters, the formulated process needs to be particularly fine, and auxiliary tooling and even tire tools are essential.

First, understand the effect of heat treatment on deformation.

Secondly, the influence of tooth processing, tooth shaping, and grinding.

Bearing ground clearance, especially negative clearance.

Auxiliary tire tools, in heat treatment, finishing machining, gear shaping, gear grinding, grinding with end face and end runout, radial runout, common normal after grinding, and tooth runout parameters, all are the connection between the process and the process, and the precise control.

Therefore, for bearing design and selection calculation, the selection of working conditions must at least meet the requirements, and there will definitely be contradictions and errors.

For precision slewing bearings, understanding the manufacturing process is the key to knowing the performance of the bearing.

China Whole Sale Popular Bucket Turbine Slewing Bearing

10 Tips for Replacement, Maintenance and Installation of Bucket Turbine Slewing Bearings

Based on the domestic bucket turbine slewing bearing 1797/3230G2K and the stacker-reclaimer slewing bearing 1797/2635, 1797/2500G, and 132.40.3550.12, 10 tips for the replacement, maintenance and installation of bucket turbine bearings are analyzed.

Analysis of Damage Causes of Rotary Large Bearings
The reasons for the damage of the large bucket turbine slewing bearing are:

(1) The large bearing has been running for 8 to 12 years, and the cycle is long, and the defects have been exposed during the overhaul;

(2) The foundation of the walking track of the bucket turbine has been running unevenly for many years. Shen, the bearing is in an inclined state when working, and is subjected to additional force to accelerate wear;

(3) Bearing
The vulcanized rubber seal is aging, and dust enters the inside of the bearing; (4) Overloading when coal is taken.

Item Lift Replacement of Slewing Large Bearings
Use the “lifting method” to replace the large slewing bearing of the bucket turbine by yourself: lift the part above the slewing unit as a whole and replace the Bucket Turbine Slewing Bearing.
Ready to work

The weight of the part above the slewing platform of the bucket turbine is about 270 t-350T, and the cantilever is 30m long. Although there is a counterweight mechanism, the center of gravity of the part above the slewing platform is still inclined to the cantilever – – side, and the distance between the center of gravity and the geometric center is about 0.5 m.

The cantilever must be erected, and the cantilever wire rope is slightly loosened, so that the center of gravity of the upper part of the slewing platform is closer to the geometric center, and the unbalanced force during jacking is reduced.

For this reason, on the south side of the vertical direction to the bucket wheel machine running track,The coal is piled up to about 2m above the level of the cantilever 2 months in advance. After sun exposure, rain, compaction, the cantilever supports the shelf when the bearing is replaced, which can reduce the tooling cost.

Bucket Turbine Positioning
Keep the bucket wheel cantilever perpendicular to the track, lift the cantilever, and walk the bucket wheel to the predetermined position. At this time, the front end of the bucket wheel cantilever falls on the coal pile stacked in advance (a suitable sleeper is placed between the coal pile and the cantilever), so that the cantilever is covered by coal. Stack up.

At this time, the wire rope of the counterweight mechanism is loosened, but cannot leave the pulley channel. Special attention: The tightness of the wire rope should ensure that when the upper slewing platform is jacked up to 180mn, the wire rope is still slightly loose, and the weight of the cantilever head still falls on the coal pile.
In order to maintain the balance and stability of the rotary platform. .

Fixed bucket wheel

Considering that the walking track of the bucket wheel machine is not very flat, and the bucket wheel machine may be affected by wind during construction, and the external force of the bucket wheel machine when the large bearing enters and exits, the lower body of the bucket wheel machine must be fixed with a rail clamp before construction.

At the same time, along the direction of the track, 22mm diameter steel wire ropes are used to pull the ground foundation on both sides of the height of the door beam to increase the stability of the upper body. The middle of the steel wire ropes are respectively connected – – – only pull the 3t hoist by hand, and adjust the tightness of the steel wire ropes at any time during the next lifting process of the rotary platform.
Remove accessories

The coal drop tube, cantilever belt electric drum and head guard on the rotary platform, the coal drop tube of the rotary platform is connected to a fixed coal drop tube with a length of about 500 mm, which affects the replacement of large bearings and needs to be removed. Power cables must be carefully pulled out of their protective sleeves and then cut off.
ready to lift

Each of the 4 jacking blocks is arranged – a 100T screw jack, and the jack can be lifted until it is evenly difficult. Four-corner welding is used as a steel pipe for guiding and positioning as well as a ruler. The special steel pipe is inserted into the lower steel pipe, and the two types of steel pipes are welded on the upper and lower jacking seats respectively. Then, first loosen the 36 M36 bolts on the outer ring of the large bearing.

Note that it can only be loosened at this time, because the space height is not enough, and the bolts are still inserted in the bolt holes of the large bearing. Then loosen the inner ring bolts, 36 M36 inner ring bolts are temporarily reserved for 6 evenly distributed and cannot be loosened.

Because 36 bolts of the outer ring of the lBucket Turbine Slewing Bearing are connected to the lower fixed platform, 36 bolts of the inner ring are connected to the upper slewing platform, and the inner and outer rings of the large bearing are connected to each other with 6 M24 bolts.

The key lifting, the time must be controlled within 1 day. (10 hours)
After all the parts that affect the replacement of the Bucket Turbine Slewing Bearing are removed, the 4 jacks will be lifted synchronously under the command of – – Human System – -.

During this process, pay close attention to the readings of each scale, the maximum error is controlled within 2 mm, and as required Adjust the tightness of the air line, stop when the upper slewing platform (the Bucket Turbine Slewing Bearing is still connected to it) is jacked up for 180 mo, and the jacking seat is temporarily welded with steel pipes up and down to ensure that the upper and lower platforms have no relative displacement.

Then, use 3 lifters evenly distributed on the fixed platform below the large bearing, slightly against the large bearing. At this time, the remaining 6 bolts of the inner ring can be disassembled, and the track lifter evenly drops to a distance of 6-8mm from the lower fixed platform.

The rear of the large bearing is connected to the tail car with a wire rope and a hoist, and the front part is pulled along the horizontal direction of the track. A traction Wire rope, inserted horizontally between the large bearing and the lower slewing platform – a 25mm steel pipe is used as a roller, and the length is equal to the outer diameter of the large bearing.

Continue to drop the elevator until the large bearing falls on the roller. Under the protection of the machine, remove the lifter, and use the head to pull the wire rope to slowly pull out the large bearing to two-thirds of the large bearing.
Backpack
Push in the new bearing in the same way as above, and assemble and adjust.

Practice has proved that the replacement method for the large bearing of a bucket turbine is successful, and the construction period is only

It takes 6-9 days and costs 100,000-160,000 yuan, which not only ensures safety, but also saves money, and improves the replacement procedures and processes. after replacement
After more than 1 year of operation, the rotation is stable, the large and small gears are well meshed, the operation is normal, and the rated output is reached.

4 Point Contact Ball Slewing Bearing Made In China

1.4 point contact ball slewing bearing and angular contact bearing

4 point contact ball slewing bearing

Function: 4 point contact ball slewing bearing When only pure axial load acts, the steel ball and the ferrule become two-point contact, which can bear two-way axial load. Four-point contact ball bearings can also withstand moment loads, and have both the functions of single-row angular contact ball bearings and double-row angular contact ball bearings.

4 point contact ball slewing bearings can only ensure normal work when they form two-point contact. Therefore, it is generally suitable for those occasions where there is two-point contact under pure axial load or combined load with large axial load.

The connection line between the steel ball of the angular contact ball bearing and the contact points of the inner and outer rings forms an angle with the radial direction. The contact angle is generally divided into 15°, 30°, and 40°, which are represented by the letters C, A, and B respectively. NSK specially produces such bearings with a contact angle of 25°, which is represented by A5. Angular contact ball bearings mainly bear large unidirectional axial loads, and the greater the contact angle, the greater the load capacity.

The cage material is steel, brass or engineering plastic, and the molding method is stamping or turning, which is selected according to the bearing form or use conditions. Others include combined angular contact ball bearings, double row angular contact ball bearings and 4 point contact ball slewing bearings.

4 point contact ball slewing bearing Alt.

Angular Contact Bearing

Features: The 4 point contact ball slewing bearing is a separable structure, and a single bearing can replace the angular contact ball bearing with front combination or back combination. It can bear radial load and two-way axial load, and can limit the axial displacement in two directions, but it occupies less axial space than the double row angular contact ball bearing of the current specification.

Compared with other ball bearings, 4 point contact ball slewing bearings have smaller axial clearance and higher limit speed when the radial clearance is the same. Four-point contact ball bearings are suitable for bearing pure axial load or combined axial and radial loads dominated by axial loads.

Because it is a double half inner ring (or outer ring), the number of balls is increased, and it has a larger bearing capacity. Under normal working conditions, when this type of bearing bears an axial load in any direction, it can form a contact angle, and the steel ball contacts the inner and outer raceways at one point to avoid large sliding friction in the contact area. Therefore, the bearing should not bear mainly radial force and load.

Angular contact ball bearings can withstand radial and axial loads at the same time. Can work at higher speeds. The larger the contact angle, the higher the axial load carrying capacity. High-precision and high-speed bearings typically have a 15-degree contact angle.

Under the action of axial force, the contact angle will increase. Single row angular contact ball bearings can only bear axial load in one direction, and will cause additional axial force when bearing radial load. And can only limit the axial displacement of the shaft or housing in one direction.

If it is installed in pairs, make the outer rings of a pair of bearings face each other, that is, the wide end faces the wide end face, and the narrow end faces the narrow end face. This avoids causing additional axial forces and confines the shaft or housing to the axial play in both directions.

Low Price Slewing Bearing

1.Disposal of slewing bearing maintenance and maintenance

1.1 Anti-rust and packaging

The inner and outer surfaces of the slewing bearing are evenly coated with anti-rust and lubricating oil on both sides of the bearing, and the packaging is wrapped with plastic film kraft paper and linen strips. The outer surface of the large-size slewing bearing should also be wrapped with plastic cloth. For small size slewing bearings, use wooden boxes.

1.2 Warehousing

Regardless of whether it is a new bearing or a slewing bearing that is maintained or repaired, the parts need to be individually rust-proof and lubricated. The whole piece needs to be maintained in accordance with the standard of JB/T10471, including the accuracy of the bearing, horizontal placement, dust-proof, and lubrication. During the stacking period, it is strictly forbidden to tilt, place under heavy pressure, and place in the open air. The principle of storage allowable time is 10 months. The packaging adopts three layers of protection. After adding grease, the appearance is rust-proof. Film, kraft paper, foam padding, plus wrapping tape.

transportation

Keep the bearings as horizontal as possible during transportation, only allow a slight tilt, and avoid large bumps or vibrations. After unpacking, screw the lifting bolt into the lifting hole of the inner ring or outer ring to transport the bearing to the installation position.

1.3 Safekeeping

1.3.1 In the rust-proof period before use (within 12 months after the bearing leaves the factory). Do not open the package. If maintenance is required, the raceway, outer surface and tooth surface of the slewing bearing should be treated with anti-rust treatment.

1.3.2 Lay it horizontally on a dry and flat site.

1.3.3 If the slewing bearing is stored for more than 12 months, it should be re-rusted.

1.3.4 If multiple sets of slewing bearings are stacked together, at least three evenly distributed wooden pads should be placed between each set of slewing bearings along the circumferential direction, and the upper and lower pads should be placed in the same position.

2 Installation of slewing bearing

2.1 Preparation before installation

2.1.1 The connecting surfaces of the supporting parts shall be machined, and then these surfaces shall be free of burrs and debris. In addition to the supporting parts should have sufficient rigidity, the technical requirements of the connecting surface of the supporting parts should meet the requirements of Table 1.

Technical requirements for connecting surfaces of supporting parts Table 1 µm

2.1.2 When the radial load exceeds 10% of the axial load, there should be radial positioning, and the connecting surface that cannot be machined should be flattened by injection molding.

2.1.3 When unpacking the bearing before installation, care should be taken to avoid damage to the seal and prevent dust from entering the inside of the bearing. Within the specified anti-rust period, it is not necessary to disassemble and clean before installation.

slewing bearing Alt.

2.2 Soft belt position

The quenched soft tape of the slewing bearing ring is marked “S”. When installing, the position of the soft belt should be in the non-loading area or the non-recurrent load area (the filling plug is always located at the soft belt of the ferrule.)

2.3 Ring gear inspection

Before the mounting bolts are not fully tightened, the gear meshing check should be carried out to ensure that the meshing clearance and the accuracy requirements of the gears are met.

2.4 Tightening of mounting bolts

When installing bolts, quenched and tempered flat washers can be used, and spring washers are prohibited.

After locating the slewing bearing radially, tighten the mounting bolts crosswise and check the free rotation of the bearing at the same time.

There should be sufficient pre-tightening force when tightening the bolt, and its pre-tightening force should be 70% of the yield limit of the bolt material.

3 Use and maintenance

3.1 Inspection of mounting bolts and abnormal phenomena

After about 100 hours of operation of the slewing bearing, check the pre-tightening torque of the mounting bolts of the inner ring and the outer ring, and every 500 hours of operation thereafter.

If there are abnormal phenomena such as noise, impact, and sudden increase in power during use, it should be shut down for inspection.

3.2 Lubrication

After the slewing bearing is installed, it should be filled with suitable grease according to the actual use conditions, and the slewing bearing should be filled while the grease is evenly distributed until the new grease begins to squeeze out of the sealing lip. Fill it every 50~100 hours, and the oiling cycle should be shorter in high environment and dusty conditions. New grease must also be added before and after the machine has been stopped for a long time.

3.3 Cleaning and assembly of slewing bearing

In the assembled slewing bearing, the parts between sleeves and between rows and between rows are not interchangeable. When the bearing is disassembled and cleaned, it should be carried out according to the bearing assembly drawing, and the upper and lower half rings should be assembled according to the original drilling position.

The tooth surface should be cleaned of debris every 10 days and coated with grease.

3.4 Selection of Grease

For the lubrication of the slewing bearing, because there are many comprehensive working factors, the user can choose the best grease according to the specific requirements. Recommended greases are shown in Table 2.

3.5 Maintenance and repair of heavy-duty bearings shall be carried out with reference to the operating conditions of the equipment manufacturer and the technical specifications of the bearing factory.

First Slewing Bearing Small Factory

1.Design of slewing bearing

What are the general selection steps for slewing bearings?

1. The scientific name of slewing bearing is slewing bearing. Before selecting the type of slewing bearing, the operating environment and working conditions must be clarified first.

2. Determine the maximum load on the slewing plate bearing. This load must include both dynamic and static loads applied to the slewing bearing. The load applied to the ferrule should be converted into an equivalent load acting on the center of the slewing ring.

Some must-notes:

· All external forces acting on the slewing bearing and gear, not only the rated load or working load, but also the load that may be suddenly generated when the equipment is stationary, such as the effect of strong wind on large buildings, etc.

· Possible loads in case of overload or test

· Loads generated during installation and removal

· Weight of all structures supported by slewing rings

· The sum of all possible loads. For example, a crane has various changes in load and working radius during normal use and overload testing.

3. Multiply the calculated load by the appropriate safety factor.

4. If a complete gear is required, the load to be carried by the gear needs to be determined. The calculation method is the same as the slewing bearing load and should take into account all possible situations; these include operating, stationary, tilting, and overload testing, to name a few. Another thing to note is the type of load in each case.

5. After the installation layout is determined, the position of the large and small gears, the installation and subsequent maintenance of the slewing bearing and the fastening bolts need to be considered.

6. Refer to the “Product Overview & Selection Guide” in the LYMC Slewing Bearing Operation Manual to select the slewing bearing series required for each location.

7. By comparing the previously calculated load and safety factor of the slewing bearing with the bearing characteristic curve of the slewing bearing, we can make a preliminary selection of the slewing bearing. Make sure that all load combinations are below the load characteristic curve. In many cases, we now have several options for slewing bearings, all of which can meet the load requirements.

8. If possible, check the gear load capacity of the selected slewing ring.

9. Confirm that the arrangement of fixing bolts, fixing plates and joints is suitable for installation.

slewing bearing Alt.

2. Selection elements of slewing bearing

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, and at the same time, the moment of inertia is reduced for the occasions where the rotational speed is high and the structural deformation is required to be small.

China Industrial Positioners Slewing Bearing Manufacturer

1.Ball Raceway Advantages of Slewing Bearings

The raceway of the slewing bearing is divided into a ball raceway and a ball raceway. The advantage of the ball raceway is that it has four-point contact, is flexible, and has resistance to fatigue.

Therefore, the application field of the slewing bearing in the four-point contact is generally heavy load Crane bearings under 100 tons, excavator bearings, crane bearings and crawler crane bearings, cement pump truck bearings with double row ball bearings, and the like.

The raceway is a ball bearing with a linear raceway, which is generally suitable for heavy-duty fields and requires a good cage design. Because the ball is prone to sliding friction on the horizontal raceway, not the raceway friction, to put it bluntly, the ball is prone to slipping on the raceway surface, and the rotational performance is far inferior to that of a ball bearing.

The advantages of ball bearings are flexible, widely used, and poor in heavy loads. Ball bearings have good high load-carrying performance, but poor rotational flexibility and are suitable for low-speed rotation.

2.Clearance value of slewing bearing

Three interpretations of the clearance of the slewing bearing and the clearance value of the slewing bearing:

1. Compensate for manufacturing errors

2. Make up for the loss of installation accuracy

3. Meet the requirements of the working conditions for the rotation accuracy

Whether it’s important or not can’t be generalized. The clearance value of the bearing is artificially divided and specified, and is divided into a certain range according to the size, which is used as a reference value in the processing process.

Therefore, if it is not specially required by the working conditions, the clearance of the bearing can be allowed within a certain range. It is generally considered that the overflow space of 0.05/0.1, even if it is out of tolerance, is not enough to affect the quality of the slewing bearing itself.

Secondly, the clearance of the slewing bearing also compensates for the installation error. If the clearance is too small and the installation plane is very rough and uneven, a certain clearance value can be relaxed, so as to ensure the normal rotation of the bearing, so as to prevent the bearing from being installed and affected by Uneven force, stuck and unsmooth rotation under partial load.

Of course, the regulation of the clearance value cannot be sloppy when the design rotation accuracy is high. Generally speaking, 0 clearance or negative clearance, at least ensure that the bearing cannot have clearance, that is, stop immediately and point accurately, Repeated positioning and starting torque are all actions that are specifically realized under the design of working conditions.

At this time, the clearance is very important for the slewing bearing. Even if the starting torque is not within the test range, the clearance value is guaranteed to be within -0.02/0.

slewing bearing Alt.

3.Slewing Bearing advantage

Advantages and applicable working conditions of four-point contact ball slewing bearing The four-point contact ball bearing is a single-row angular contact ball bearing, and its raceway is designed to withstand bidirectional axial loads. The contact angle can be 30 degrees, 35 degrees, and 45 degrees.

The inner ring can be divided into two pieces, which can hold a large number of balls, so it has a large bearing capacity. The bearing is separable, that is, the two pieces of the inner ring and the outer ring with the ball and cage assembly can be installed separately. Four-point contact ball slewing bearing has a compact structure and light weight.

The steel ball contacts the arc raceway at four points, which can bear axial force, radial force and overturning moment at the same time, and has strong dynamic load capacity.
Applicable working conditions: The load is generally below 100T, and you can choose single-row four-point contact ball bearings, double-row ball contact ball bearings, and ball-ball combination bearings. The overall cage and segmented cage can be used to improve stability and service life, and the rotation speed can be appropriately increased to 30rpm-120rpm.

The accuracy level is best controlled.
At present, the common four-point contact balls include excavator bearings, truck crane bearings, crane bearings, crawler crane bearings, turret bearings, CT machine bearings, bottle blowing machine bearings, filling machine bearings, turntable bearings, and crane bearings. etc.

Kaydon Slewing Ring Factory

1.Proportional relationship between correct installation of slewing ring and service life

As a precision rotating core component, the kaydon slewing ring, the clearance value, the end runout, the axial runout and the radial runout, are all calculated by the wire and the track. It is very important to ensure the correct and precise installation of the slewing ring. Affect the service life and use effect of the bearing.

Notes on installation:

3. The seal is the lubrication system of the bearing. Check whether the seal is still in the correct position, and clean the fitting part of the mounting plane of the kaydon slewing ring.

It is strictly forbidden to weld the kaydon slewing ring to avoid the deformation of the inner and outer rings, which will affect the normal use.

8. After the installation work, the raceways and gears should be filled with grease and regularly maintained.

9. Make sure that the gear meshing reaches 70% and the force is even.

2.Sealing strip design skills and installation of kaydon slewing ring

kaydon slewing ring Alt.

Embedded sealing strip, also known as invisible sealing strip, embedded sealing strip.

The advantage of the built-in sealing strip is that the structure of the slewing ring is increased, and the grease is lubricated in a small range, preventing excessive consumption and loss, reducing the drop between the inner and outer rings, and increasing the rolling elements of the bearing to improve the load.

The disadvantages are also obvious. The damage is not easy to maintain and install again. Professionals are required to open the bearing again for installation. The wear and consumption of the built-in sealing strip are invisible, which increases hidden dangers.

The trouble caused by the installation is that it is not easy to install the bearing after the sealing strip is assembled in advance. Small gap, squeeze, easy to interfere. Design considerations, calculate the pressure and size of the sealing strip in advance, and the depth of the sealing groove in advance, so that the sealing strip can be buried as much as possible. Secondly, the installation of the sealing strip should follow the installation direction as much as possible, otherwise it is easy to get stuck in the gap of 0.5mm.

There are also design features, pay attention to the lip shape of the built-in sealing strip to ensure that the rotation performance cannot be affected after installation.

Finally, the practical occasion of the built-in sealing strip is to ensure that the bearing under 1 meter is used in the four-point ball and crossed roller bearing structure. The bearing structure should not be complicated.

3.The role of full complement ball and spacer block cage for slewing ring

When the drawings and technical requirements of slewing ring and slewing bearing are normally designed, spacers or cages are generally used unless the bearing capacity of the bearing is intentionally increased with full complement of steel balls or full complement of rollers.

The main purpose of the spacer block or cage, as shown in the figure, is to coordinate the movement trajectory and movement direction of the rolling element, and to uniformly bear the force. Reduce friction between rolling elements and reduce impact noise. Thereby improving the rotational performance of the bearing.

When fully loaded, the rotational flexibility of the bearing is not affected. Because they are all at low speed and heavy load, it is not enough to affect the test data of the bearing. What is the effect of installing isolation blocks? The reason is self-evident, which is to improve the movement efficiency of the rolling elements.

The role of full complement ball and spacer block cages for slewing bearings and slewing rings
Relatively speaking, cages, especially integral steel cages, copper cages, and teflon cages, are very important for bearings that are subjected to inclination angle force, vertical force, and tossing force. Integral cages must be used.

Especially large-diameter slewing bearings, segmented cages, and integral cages cannot be replaced.

For four-point contact ball bearings, the integral cage can improve the life and reliability of the bearing.

Precision Crossed Cylindrical Roller Slewing Bearings

What a crossed cylindrical roller slewing bearings?

Crossed cylindrical roller slewing bearings are bearings for high-precision applications whose dimensions conform to ISO dimension series 18 as per DIN 616. They comprise outer rings, inner rings, rolling elements and plastic spacers. The outer ring is split and is held together by three retaining rings.

Due to the X arrangement of the crossed cylindrical roller slewing bearings, these bearings can support axial forces from both directions as well as radial forces, tilting moment loads and any combination of loads by means of a single bearing position.

As a result, designs involving two bearing positions can be reduced to a single bearing position. Crossed cylindrical roller slewing bearing are very rigid, have high running accuracy and are supplied with normal clearance, low clearance or preload. The crossed cylindrical roller slewing bearing outer rings are easily fixed to the adjacent construction using clamping rings.

Crossed Cylindrical Roller Slewing Bearings Alt.

LYMC designs and manufactures a variety of crossed cylindrical roller slewing bearings that can handle radial, thrust and moment loads at the same time. These compact bearings feature rollers crossed at right angles between inner and outer rings.

Widely used in machine tools, industrial robots and medical equipment because of their high rotational accuracy.
Roller guide options include a cage or separator as well as a full complement design. Both the cage and separator styles offer a small coefficient of friction for high-speed rotation. Full complement crossed cylindrical roller slewing bearings handle heavy loads at low speeds.
Sealed and open designs are available. Sealed bearings incorporate synthetic rubber seals to protect against dust, dirt and grease.
Mounting Holed Type
Mounting holed type, high rigidity crossed cylindrical roller slewing bearings feature mounting holes on both inner and outer rings for easy installation.
- Inseparable design integrates inner and outer ring into one structure for high rigidity and accuracy.
- Shaft diameters range from 10 to 90 mm.
- High Rigidity
  
  High rigidity crossed cylindrical roller bearings feature solid, one-piece construction for high accuracy.
  
  Inseparable design integrates inner and outer ring into one structure for high rigidity.
  
  Smooth rotation ensured by separators incorporated between cylindrical rollers, suitable for high rotational speeds.
  
  Shaft diameters range from 20 to 300 mm.
  
  Standard
  
  Standard crossed roller bearings feature a two-piece outer ring, bolted together to prevent separation during transport and installation.
  
  Shaft diameters range from 30 to 250 mm.
  
  Available in caged and full complement types.
  
  CRB and CRBC are available with shaft diameters as large as 800 mm.
  
  Definition of crossed roller bearings
  
  Crossed roller bearing is a special type bearing with split inner ring and rotating outer ring. Since the divided inner ring or outer ring is installed with rollers and cage, it is fixed with the cross roller ring to prevent separation from each other, so it is easy to install the cross roller ring.
  
  Since the rollers are arranged in a cross, only one set of cross roller rings can bear loads in all directions. Compared with the conventional model, the rigidity is increased by 3 to 4 times. At the same time, because the inner ring or outer ring of the cross roller bearing has a two-part structure, the bearing gap can be adjusted, and even if preload is applied, high-precision rotational movement can be obtained. Moreover, due to its special structure, it is usually used as a joint bearing in industrial robots.
  
  Applications of crossed roller bearing:
  
  •Industrial robot arms, reducers
  
  •Precision machines( turnable table)
  
  •Rotation parts of Machine tools
  
  •Medical equipments
  
  • Measuring instruments
  
  LYMC-bearing provides high quality crossed roller bearings including THK RA, THK RB, THK RE, THK RU series, IKO CRB, IKO CRBC, IKO CRBF, IKO CRBH, INA SX, INA XU, INA XSU series and more. Custom cross roller bearings are also acceptable.

Slewing Bearings Suppliers Plant

1.The necessity of grinding teeth for slewing bearings

Regarding the slewing bearing or slewing ring bearing, no matter external or internal teeth, helical teeth, etc., the normal process level includes gear shaping, gear hobbing, and milling. According to the design standard, the gear accuracy is generally 9-grade or 10-grade teeth.

Here, the 9th grade teeth or the 10th grade teeth, the indicators under investigation are based on the design standard of the slewing bearing of JB/T10471, and you can also refer to JB/T2300. It mainly reflects the rotation accuracy, and the specific indicators are:
1. Number of cross teeth and length of common normal
2. Common normal deviation
3. Tooth jump (tooth jump of finished turntable bearing)
4. The tooth width, tooth thickness, tooth shape and tooth direction are generally not marked separately in the drawings.

In short, the values of the 9-stage teeth or 10-stage teeth of the slewing bearing are in agreement in a pure sense. From the design concept, the common normal of the 7th grade and 8th grade teeth, the tooth jump also meets the design requirements.

However, the quenching of the tooth surface has a great influence on the accuracy level of the tooth surface, and it is generally one level backward.

This article talks about the necessity of grinding teeth and the technical indicators that can be achieved.
1. Improve meshing accuracy
2. Tooth jump 0.06-0.15mm
3. Tooth surface roughness Ra0.8
4. Reduce meshing noise
5. Reduce the wear intensity of the tooth surface
Therefore, if you want to reach this technical level, you must grind the teeth.

slewing bearings Alt.

2.Design parameters to improve slewing bearing life and reliability

Slewing Bearings life

Under a certain load, the number of revolutions or hours that a bearing experiences before pitting occurs is called bearing life.

Due to the difference in manufacturing precision and material uniformity, even the same batch of bearings of the same material and size will have different lifespans when used under the same working conditions. If the statistical life is 1 unit, the longest relative life is 4 units, the shortest is 0.1-0.2 unit, and the ratio of the longest to the shortest life is 20-40 times.

In order to determine the standard of bearing life, the slewing bearings life and reliability are related.

Work on the following design factors:

1. Structure, choose three-row roller combination slewing bearing

2. Material, choose 42CrMo, electroslag remelting

3. Quenching and tempering hardness should be above HB280

4. High manufacturing precision

5. The height of the ferrule and the size of the roller should be matched

6. Tooth surface quenching

7. Protective measures, seals and dust baffles

8. Application of integral cage

3.What factors should be paid attention to when surveying and mapping high-precision slewing ring bearings

For surveying and mapping of high-precision slewing bearings, in addition to paying attention to the installation size, in the process of surveying and mapping most slewing bearings, we must grasp the necessary technical parameters to ensure that the surveying and mapping bearings are foolproof. So what parameters must be paid attention to? What preparations are needed for high-precision surveying and mapping points?

1. The outer dimensions of the slewing bearing are necessary

2. The gear parameters of the slewing bearing, the primary

3. The size of the mounting hole of the slewing bearing, including the number, position, size and type

4. Step size, lubricating oil hole, position, number, size, type of slewing bearing

5. Structural form, must be disassembled and viewed

6. Seal form, cage form and channel type

7. Working conditions, accuracy, horizontal, inclined and vertical use

4.What are the quality standards for large bearings of slewing ring

In short, if you have to distinguish from the selection, quality reliability and high standards of bearings, you can refer to the following:

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 specific tests are as follows: the high-frequency quenching hardness of the 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.

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