Bearing Knowledge - LDB

What are the self-locking methods of spur gear drive?

September 7, 2021/in Spur Gear Drive Knowledge /by ldbadmin

Spur gear drive is also a kind of gear type slewing drive. Its transmission principle is a device in which the pinion drives the gear ring of the slewing ring to rotate and reduce. From the deceleration principle of the slewing drive, we can find that it does not have the self-locking function. Yes, if you want to achieve exact stop, you need to use a brake device for locking. The editor of Ronda will introduce to you the self-locking methods of spur gear drive.

What is spur gear drive self-locking

Spur gear drive self-locking is to manually stop the drive when it needs to be stopped. The main use of the self-locking principle is that when the transmission angle, that is, the complementary angle of the pressure angle, is less than one-half of the friction angle, the conditions for self-locking can be achieved. That is to follow the self-locking phenomenon, when the resultant force of the transmission force of the object acts within the friction angle, no matter how great the force is, there will always be a total reaction force to balance it and keep the object still. However, the spur gear drive cannot achieve self-locking and needs to rely on external force to complete the drive locking effect. The following specifically introduces the ways to realize the self-locking of the spur gear drive.

Self-locking method of spur gear drive

1. Servo motor self-locking

When the spur gear slewing drive is driven by a servo motor, when the driving force is small inertia, that is, the starting is frequent and the load is small, the servo motor is usually stopped to achieve the locking of the spur gear drive. The locking force of the servo motor is passed The reduction ratio of the spur gear drive is amplified, and then reflected on the turntable to achieve drive locking. At this time, the locking force is relatively large, which is very suitable for working conditions with small inertia.

2. Self-locking hydraulic motor

The spur gear drive using hydraulic motor can be braked by the hydraulic motor during use, so as to realize the locking of the spur gear drive. Among them, the hydraulic motor braking method is divided into the following three types:

(1) Braking with overflow valve: It can realize bidirectional braking to the hydraulic motor, and can play a buffering effect.

(2) Braking with accumulator: Install accumulators near the oil inlet and outlet of the hydraulic motor to achieve bidirectional braking on the hydraulic motor.

(3) Braking with normally closed brake: When the hydraulic oil in the brake hydraulic cylinder loses pressure, the brake will act immediately to achieve braking.

3. Self-locking brake reducer

The disc brake that uses the spur gear of the brake reducer to drive the brake motor is installed on the end cover of the motor’s non-output end. When the brake motor is connected to the power supply, the electromagnet attracts the armature and the brake armature is separated from the brake disc and the motor starts When the brake motor loses current, the electromagnet cannot attract the armature, the armature falls back to the brake disc, and the motor stops rotating. The self-locking effect of the spur gear drive is realized through the characteristics of the brake motor’s power-off braking.

4. Bolt brake

What are the self-locking methods of spur gear drive? You can also install a pin hole on the gear drive to lock the spur gear drive that requires a fixed position. At the beginning of the design, a pin hole is designed on the rotating ferrule, and a starter or hydraulic pin device is designed on the frame. During the driving process, the bolt mechanism can pull out the pin to allow the drive to rotate normally. Insert the pin back into the bolt hole at the position where it needs to be stopped and fixed. The drive is fixed on the frame by the pin of the ferrule and cannot rotate. Realize self-locking.

5. Self-locking brake gear

A separate brake gear is installed on the rotary drive. This method is suitable for situations where frequent braking is required and the spur gear drive power is large and the braking power is large. Large braking force will cause the failure of the connection between gears, reduction gears, and motors, and shorten the service life of the spur gear drive. For this reason, the spur gear drive with independent brake gears can be used to achieve separate braking to avoid the transmission force. The connecting parts fail due to the sudden braking, and the parts are damaged.

The above is the main introduction about the self-locking methods of the spur gear drive. The realization of the self-locking function of the slewing drive can be selected according to the specific equipment operating conditions and requirements.

Scrap Standard and Service Life of Tower Crane Slewing Bearing

August 30, 2021/in Slewing Bearing Knowledge /by ldbadmin

All machines will suffer loss and failure after a long period of use. When the parts exceed the service life or are damaged beyond repair, they should be scrapped and replaced. The tower crane slewing bearing is prone to failure and damage when subjected to harsh outdoor environments and high-load operation for a long time. So to what extent can it meet the scrap standard of the tower crane slewing bearing?

The scrap standard of tower crane slewing bearing

1. The slewing ring and rolling elements are worn out and scrapped

The wear of raceway ring and rolling element is one of the common forms of slewing bearing scrap. When the raceway pitting corrosion occurs on the surface of the slewing bearing, the surface metal is peeled off and the overall wear is worn, the tower crane will experience abnormal noise, rolling element jamming and excessive clearance between the raceway rings during operation; vibration and local impact will be caused. With the development of the state, the turning resistance will continue to increase and the turning function will be lost.

2. The slewing ring cage is damaged and scrapped

In order to avoid friction between the rolling elements of the tower crane slewing support, an isolator cage is usually added between the rolling elements. The material of the cage is generally copper, plastic, powder metallurgy or mild steel. The cage does not transmit load during the bearing, but it moves with the rolling elements. When the cage is damaged or broken, there will be a sharp and piercing noise. As the broken body of the cage is pushed and crushed by the rotating rolling elements, it will cause serious damage to the raceway ring and rolling elements. At this time, the slewing bearing meets the scrap standard and can be replaced.

3. The slewing ring teeth are damaged and scrapped

The gear meshing mode of the tower crane slewing support has two kinds of external gear meshing and internal gear meshing. When the surface of the gear teeth is excessively worn, cracks and broken teeth appear. The tooth side clearance of the gear teeth of the tower crane slewing bearing is enlarged, and the slewing bearing will immediately lose its function when the tooth is broken and cannot be repaired. At this time, it reaches the scrap standard of the tower crane slewing bearing.

4. The slewing ring connecting bolts are damaged and scrapped

Although the connecting bolt of the slewing ring is not the bearing body, the failure of the bolt will also cause the slewing ring to fail to work. The damage of connecting bolts in tower crane work is also a common phenomenon. When a slewing bearing connecting bolt is loosened or broken, it will often cause a chain reaction to cause the loosening and fracture of other bolts. At this time, the slewing bearing also needs to be replaced.

5. The slewing bearing is damaged and scrapped due to corrosion and burns

Due to the complex working environment of the tower crane slewing bearing, the situation that the bearing may encounter is also unpredictable. If it is corroded by corrosive substances such as acid and alkali during operation, the internal components of the bearing will be damaged and the bearing will be scrapped.

The service life of the tower crane slewing bearing

Under a certain load, the number of revolutions or hours that the bearing experiences before pitting corrosion is called the bearing life. The service life of the tower crane slewing bearing is affected by the speed, radial load, basic rated load, equivalent conformity, speed coefficient, and fatigue life coefficient.

1. Calculation formula of bearing life

L10-When the bearing load is P, the basic rating life (106 revolutions)

C–Basic dynamic load rating N

ε–index

Ball bearing: ε=3

Roller bearing: ε=10/3

P–Equivalent dynamic load (N)

The load on the bearing under actual conditions: A, R, transformed into the load under experimental conditions is called equivalent dynamic load. For bearing components, this load is variable. In the experimental study, the bearing life is changed to 106 The unit is more convenient (counter), but in actual production, the life is generally expressed in hours. For this reason, it must be converted L10×106=Lh×60n

2. Calculation method of tower crane slewing bearing life

(1) Knowing the bearing model, load and shaft speed, calculate Lh;

(2) Knowing the load, speed and expected life, calculate C and select the bearing model.
Usually take the middle repair or overhaul limit of the machine as the design life of the bearing, generally Lh’=5000, and the temperature coefficient ft should be introduced for the bearing working at high temperature

Ct=ftC

t ≤120 125 150 200 300

ft 1 0.95 0.90 0.80 0.60

The above is about the relevant content of the scrap standard of the tower crane slewing bearing. The tower crane’s service life may be affected due to its complicated use environment. At the same time, good maintenance and repair can also extend the service life of the tower crane slewing bearing.

What are the reasons for the deformation of the slewing bearing?

August 28, 2021/in Slewing Bearing Knowledge /by ldbadmin

Slewing bearings are widely used on rotating machines such as ferris wheels and excavators, and the wide range of applications also reflects that the work load of slewing bearings is relatively high, and high-load work makes slewing bearings in use. Many problems will be encountered, and bearing deformation is one of the more common problems. So, what are the reasons for the deformation of the slewing bearing? How can we control the deformation of the slewing bearing? The slewing bearing manufacturer will introduce the related problems of the deformation of the slewing bearing, and I hope it will be helpful to everyone.

Causes of deformation of slewing bearings

1. Irregular installation

In fact, there are still more attentions in the installation process of slewing bearings. For example, in the process of bearing installation, it is necessary to accurately calculate the interference of the rotating ferrule and the appropriate fit of the fixed ferrule. Especially slewing bearings work on machines like excavators, ferris wheels, etc., and the temperature rises easily during the working process. At this time, special attention should be paid to the matching of the rotating ring not to be too loose to prevent eccentric vibration, and There must be no gap in the fit of the fixed ferrule to prevent the ferrule from deforming under load and excite vibration, which will affect the service life of the bearing.

2. Bearing wear

Wear is almost accompanied by the entire life cycle of the machine, but this natural wear has a certain degree of stability. However, if the amount of lubricating oil is too low or missing, it will cause rapid wear of the bearing, and the damage to the bearing by this unnatural wear will be irreversible. Only by overhauling the machining accuracy and straightness of the bearing can it be completely repaired.

3. Friction heat generation

During the working process of the slewing bearing, the temperature rises due to the load of the workpiece and the friction between the bearing rolling elements and the inner and outer rings, which causes the bearing to deform due to heat expansion. If the amount of lubricating oil is sufficient and effective, this kind of thermal deformation can be effectively curbed. I am afraid of the dry grinding caused by the lack of lubricating oil in the second case mentioned above. In this state, not only will the bearing raceway wear and out of stock, but also a large amount of frictional heat will be generated, which will cause bearing damage and premature failure.

Methods to prevent deformation of slewing bearings

1. Reasonable installation

(1) Keep hands clean and dry when taking out: When the turntable bearing is taken out of the package, the operator’s hands should be kept clean and dry, because sweat on the hands can cause rust, and gloves can be worn if necessary. However, it is necessary to pay attention to gloves. It is recommended to use cotton gloves to avoid scratching the bearings due to the rough surface of the gloves.

(2) Reasonable use of force: during bearing installation, the installation force should not be transmitted through the bearing rolling elements, and attention should be paid to the control of the force during installation, to avoid direct application of force to the bearing, and to minimize the effect of force on the bearing. Injury caused by the bearing.

2. Lubricate correctly

(1) Lubricant selection: When choosing the right grease for rolling bearings, you usually need to consider the following factors: bearing type, speed, working temperature and load, as well as installation position, sealing, shock and vibration, and consideration The requirements of laws and regulations and environmental protection, only to meet these requirements is a more suitable grease.

(2) Grease adding method: common slewing bearing grease adding methods include oil mist lubrication, oil-air lubrication, grease lubrication, jet lubrication, etc. Among them, grease lubrication does not require any equipment and is a relatively common lubrication method. The lubrication method is simple and easy to operate. Other methods have their own advantages. You can consider them according to the situation.

3. Ensure that the slewing bearing is clean

(1) Bearing cleaning: When cleaning, you should first pinch the inner ring of the bearing with one hand, and slowly rotate the outer ring with the other hand, until the oil on the rolling elements, raceways and cage of the bearing is completely washed off, then clean the bearing. The surface of the outer ring. At the beginning of cleaning, it should be rotated slowly, swayed back and forth, and rotated too hard, otherwise the raceways and rolling elements of the bearing will be easily attached to dirt.

(2) Isolation of impurities and dust: Bearings are easy to hide dirt and dirt. After all, the working environment of bearings is more complicated. Therefore, after the bearing cleaning work is completed, it is recommended that you use a layer of grease to seal it. This can reduce bearing contamination.

The above is a summary of the reasons for the deformation of the slewing bearing, the reasons and prevention methods. It can be seen that the reasons for the deformation of the slewing bearing include irregular installation, bearing wear, friction and heat generation, etc., and the corresponding prevention Measures include reasonable installation, effective lubrication, and keeping clean.

What should I do if the slewing drive leaks?

August 23, 2021/in Slewing Drive Knowledge /by ldbadmin

Slewing drive is also called slewing reducer and slewing spur gear drive. Slewing drive oil leakage often occurs during the operation of the equipment, but there are many reasons for the oil leakage, and the solutions are also different. So what should I do if the slewing drive leaks gear oil? The following is a brief introduction by the slewing drive manufacturer on the cause and solution of the oil leakage of the slewing drive.

Reasons for gear oil leakage in slewing drive

1. The pressure difference between the inside and outside of the slewing drive

In a closed drive, each pair of gears meshing and friction will generate heat. According to Boyle Mario’s law, as the operating time increases, the temperature in the slewing drive box gradually rises, and the volume in the reducer box No change, so the pressure in the box will increase accordingly, and the lubricating oil in the box will be splashed and spilled on the inner wall of the reduction box. Due to the relatively strong oil permeability, under the pressure in the tank, where the seal is not tight, the oil will seep out from there.

2. The design of the slewing drive itself

The designed reducer has no ventilation hood or no breather plug on the peephole cover; the shaft seal structure design is unreasonable, and the oil groove and felt ring shaft seal structure is adopted. The compensation performance of the felt is extremely poor, which causes the seal to fail in a short time. ; Although there are oil return holes on the oil ditch, it is very easy to block and the oil return effect is difficult to play.

During the manufacturing process, the casting has not been annealed or aging treated, and the internal stress of the casting has not been eliminated, resulting in deformation and gaps resulting in oil leakage; there are defects such as sand holes, slag inclusions, pores, cracks, etc.; oil leakage caused by poor processing accuracy, due to deceleration The existence of factors such as low machining accuracy of the matching surface of the chassis body, improper tolerances, and non-conforming assembly requirements may cause the reducer to leak oil.

3. Excessive lubricating oil

During the operation of the slewing drive, the oil pool is greatly agitated, and the lubricating oil splashes everywhere in the machine. If the amount of lubrication is too much, a large amount of lubricating oil will accumulate on the shaft seal, joint surface, etc., resulting in leakage.

4. Insufficient installation accuracy

Oil leakage caused by poor installation accuracy. The reducer bears a huge dynamic load when it is started. Once the installation accuracy of the reducer does not meet the standard requirements, the base bolts of the reducer will be loosened, which will aggravate the vibration of the reducer and make the seal ring at the high and low speed shaft holes of the reducer. The wear is intensified, causing the lubricating oil to flow out. At the same time, when the equipment is overhauled, due to incomplete removal of dirt on the bonding surface, improper selection of sealant, reverse installation of the seal, and failure to replace the seal in time, oil leakage may also occur.

5. The lubricating oil model is wrong

Generally, the slewing drive often uses HJ-40, HJ-50 mechanical lubricants, and can also be lubricated with HL-30, HL-20 gear oils and HJ3-28 rolling machine oils. In short, the lubricating oil of the reducer should be selected according to the load, speed, temperature and other conditions. It is wrong to blindly pursue the viscosity of the lubricating oil, the better.

The solution to the leaking gear oil of the slewing drive

1. Improve the breathable cap and inspection hole cover

Aiming at the problem of oil leakage of the slewing drive caused by the pressure difference, it can be solved by improving the vent cap and the inspection hole cover. Although the reducer has a vent cap, the vent hole is too small, and it is easy to be blocked by dust and oil. In addition, the inspection hole cover must be opened every time the oil is refilled, and opening once will increase the possibility of oil leakage, causing leakage in places that did not leak. To this end, an oil cup-type vent cap can be made, and the original thin inspection hole cover is changed to 6mm thick, and the oil cup-type vent cap is welded to the cover plate. The diameter of the vent is 6mm, which is convenient for ventilation and makes the machine The internal and external pressures are balanced. When refueling in the future, you can directly add oil through the oil cup without opening the inspection hole cover to reduce the chance of oil leakage.

2. Unblock the lubricating oil return channel

The oil spilled on the inner wall of the box should flow back to the oil pool as soon as possible, and do not store it in the shaft head seal to prevent the oil from gradually leaching out along the shaft head. For example, an oil seal ring is designed on the shaft head of the reducer, or a semicircular groove is glued to the upper cover of the reducer at the shaft head, so that the oil splashed on the upper cover flows to the return pool along both ends of the semicircular groove.

3. Improve sealing materials

(1) Slewing drive shaft seal with output shaft as half shaft Improved belt conveyor, screw unloader, impeller coal feeder and other equipment. The output shaft of reducer is half shaft, which is more convenient for modification. Disassemble the reducer, remove the coupling, take out the shaft seal end cover of the reducer, machine the groove on the outer side of the original end cover according to the size of the supporting frame oil seal, install the frame oil seal, and the side with the spring is inward. When reinstalling, if the end cover is more than 35 mm away from the inner end surface of the coupling, a spare oil seal can be installed on the shaft outside the end cover. Once the oil seal fails, the damaged oil seal can be removed and the spare oil seal can be pushed into the end cover. Eliminate the time-consuming and laborious processes such as disassembling the reducer and disassembling the coupling.

(2) The output shaft of the reducer shaft seal of the entire shaft is improved. The output shaft of the reducer of the entire shaft transmission has no coupling. If the above scheme is modified, the workload is too large and unrealistic. In order to reduce the workload and simplify the installation procedure, a split-type end cover was designed, and an opening-type oil seal was tried. The outer side of the split end cover is machined with grooves. When installing the oil seal, first take out the spring, saw the oil seal into an opening, and sleeve the oil seal on the shaft from the opening, butt the opening with adhesive, and then install the opening upward. Put on the spring and push in the end cap.

4 Using polymer composite materials

Polymer composite materials are based on high molecular polymers, metal or ceramic ultra-fine powders, fibers, etc., which are composited under the action of curing agents and curing accelerators. Various materials complement each other in performance and produce a synergistic effect, so that the comprehensive performance of the composite material is better than that of the original composition material. With strong adhesion, mechanical properties, and chemical corrosion resistance, it is widely used in the repair of mechanical wear, scratches, pits, cracks, leakage, casting sand holes, etc. of metal equipment, as well as various chemical storage tanks , Chemical anti-corrosion protection and repair of reaction tanks and pipelines.

For the leakage of the static sealing point of the slewing drive, the polymer composite material and technology can be used to control the leakage on the spot. There is no need to disassemble, and the polymer composite material is used to control the leakage externally, which saves time and effort, and the effect is immediate. Oil resistance and 350% stretch, overcoming the influence of the vibration of the reducer, has well solved the problem that the company has not been able to solve for many years. If the static seal point of the reducer leaks oil during operation, the oil surface emergency repair agent of surface engineering technology can be used to stick the plug, so as to achieve the purpose of eliminating the oil leakage.

5. Improve the maintenance process

During the overhaul of the slewing drive, the process regulations must be carefully implemented. The oil seal must not be installed reversely, the lip must not be damaged, the outer edge must not be deformed, the spring must not fall off, the joint surface must be cleaned, the sealant must be evenly applied, and the amount of oil must not exceed the scale of the oil dipstick.

6. Do a good job of cleaning

The static sealing point of the slewing drive can generally be leak-proof through treatment. However, due to the aging of the seals, poor quality, improper assembly, and high surface roughness of the shaft, the dynamic sealing points will cause small leakage at individual dynamic sealing points. Due to the poor working environment of cement companies, the dust sticks to the shaft and it is almost greasy. Therefore, it is necessary to wipe off the oil stains on the shaft after the equipment is stopped.

What to do if the gear oil leaks in the slewing drive From the above-mentioned reasons and treatment methods of oil leakage, the common oil leakage problems can basically be solved. We should pay attention to the maintenance and regular maintenance of the reducer when using the slewing drive in daily life, which can better prevent the occurrence of oil leakage, and at the same time extend the operating life of the slewing drive to ensure its good working condition.

How long is the service life of the slewing bearing? What are the factors that affect the service life?

August 20, 2021/in Slewing Bearing Knowledge /by ldbadmin

How long is the service life of slewing bearings in general? There are many factors affecting the service life of a bearing. Different working conditions, different materials, and different bearing types will affect the service life of the bearing. For this reason, the service life is not a standardized number but is based on the material, process, and production level during production. As well as the use method, maintenance lubrication conditions and other factors in the process of use, it is comprehensively determined. Let’s take a look at the factors that determine the service life of the bearing and the method of extending the service life with the slewing bearing manufacturer.

How long is the service life of the slewing bearing?

According to the influence of the bearing material, assembly, tolerance fit, lubrication and other factors, the service life of the slewing bearing under normal conditions ranges from 10,000 to 192,000 hours. We generally say that the service life of bearings is different on different types of bearings. Like ordinary bearings, the service life of the bearing refers to the failure of use, such as pitting, spalling and other conditions that cannot work normally. For spindle bearings and precision bearings that require high precision, they will fail when the running accuracy of the bearing fails to meet the requirements, but it is far below the standard for ordinary bearing failure. So this is also the reason why the service life of the slewing bearing is different.

Factors affecting the service life of slewing bearings

1. Manufacturing factors

(1) Design: Whether the diameter, quantity, ring wall thickness, effective length of rolling contact, tightness, radian and size of the raceway contact surface of the bearing rolling elements are compatible with the adapted equipment.

(2) Material: Martensite in the quenched steel during the bearing production process, impurities in the steel, chemical composition, gas, cracks, etc. The impact of the material on the quality of the bearing is hard damage, which cannot be compensated by technology in the later stage.

(3) Manufacturing: In the process of producing slewing bearings, bearing parts hardness, bearing metallographic structure, surface burns, bump scratches, roughness, poor parts grouping, production accuracy, bearing clearance, cleanliness, residual magnetism and parts Residual stress on the working surface will affect the service life of the bearing. The impact during the manufacturing process is similar to the inherent quality problem. Under the same working conditions, a defective bearing has a shorter life than a standard and qualified bearing.

2. Use factors

(1) Model selection: In terms of model selection, such as bearing load, hardness, operating environment, etc., a good bearing design will first enable the bearing to reach the upper limit of the theoretical life.

(2) Assembly: the installation accuracy of the bearing, the matching degree of the bearing shaft and the seat hole, the selection of various parts, dimensions, shape and position accuracy, the selection of assembly tools, and the cleanliness of installation whether there are impurities mixed in, including the assembly position and assembly of each part Clearance, preload size, lubricant selection and filling amount, etc.

(3) Working environment: The working temperature and the cleanliness of the working environment affect the service life of the bearing. If the operating environment of the bearing is in a harsh environment or a high temperature, high temperature, low temperature and severe cold environment, it may affect the performance of the bearing. The service life has a certain impact.

(4) Load: Each bearing has a rated load when it is produced. There is a range for the load borne during the bearing operation, that is, the force condition. If it exceeds this range for long-term overload operation, the performance of the bearing may be seriously affected. The impact of this, which in turn affects the service life.

(5) Lubrication: Bearing lubrication is a key factor in reducing the friction between the various parts of the bearing and reducing the occurrence of damage and deformation. Therefore, whether the bearing lubrication is appropriate, timely and reasonable has a certain impact on the service life of the bearing.

The above is the relevant answer about how long the service life of the slewing bearing is generally. In fact, if you want to extend the service life of the bearing, you only need to correctly select and assemble, maintain a good working environment, and use it correctly to maintain and supplement the lubricant. The service life of the bearing can be increased.

What should I do if the spur gear slewing drive shakes? Shaking causes and solutions

August 16, 2021/in Spur Gear Drive Knowledge /by ldbadmin

Spur gear slewing drive may encounter various problems during use. Generally, it can be used after adjustment. Shaking is also one of the common problems among many problems. Shaking during drive operation may affect the overall stability of the equipment. What should I do if the spur gear slewing drive shakes? Let’s work with the spur gear drive manufacturer to understand the reasons and solutions for the shaking of the spur gear rotation drive.

Causes of shaking of spur gear slewing drive

1. Excessive bearing wear: The bearing has been working for a long time, and the bearing gap will be too large or unbalanced, which will cause the bearing to generate heat and friction. The rotor and the stator will be afraid of friction, which will directly damage the bearing. The sliding bearings are prone to vibration, because the viscous effect of the lubricating oil will cause the shaft to float, and this can also be related to the weight of the bearing. If the weight of the bearing is larger, the wear will be faster.

2. High vibration of the frame: In some cases, excessive vibration of the frame may also have an impact. The vibration frequency of the frame can be said to be the rotation speed of the spur gear. It may be a problem with the frame design, which may cause an unstable state in operation.

3. Rotor mechanical imbalance: The imbalance mentioned here refers to the imbalance of the rotor in a static state and the imbalance in the case of rotation. The rotor deviates from the axis and deflection occurs under the action of centrifugal force, resulting in abnormal vibration.

4. Rotor parts are loose: several parts of the motor rotor: commutator, magnetic poles, belt pulleys, etc., these looseness will also occur when the spur gear rotary drive is used for a long time. Generally, in this case, the rotor will have noises, and these situations will occur. It should be dealt with as soon as possible, because the consequences will become more and more serious over time.

5. Leakage of the drive joint surface: Leakage on the joint surface of the reducer will cause oil shortage, oil cut, and increased wear of the gear meshing surface, shaking, and even seizure welding or breakage may occur in severe cases, resulting in equipment accidents.

6. Drive out of adjustment: When the calibration line between the motor and the driver in the gear reducer is not good, and vibration is prone to occur, adjust the calibration line and reinstall the connection between the driver and the motor, so as to stabilize the rotation of the motor bearing.

7. Rotor mechanical imbalance: The imbalance mentioned here refers to the imbalance of the rotor in a static state and the imbalance in the case of rotation. The rotor deviates from the shaft center and deflection occurs under the action of centrifugal force to produce abnormal vibration.

The spur gear rotation drive shaking solution

1. Bearing wear may need to be filled with lubricating oil and continue to be used according to the wear condition, or choose to replace the bearing when the wear is severe.

2. The vibration of the bearing frame may be a problem in the design of the slewing drive, because the vibration frequency of the base is basically the same as the rotational frequency of the bearing. Design problems can be adjusted and resolved by contacting the manufacturer’s after-sales service. For example, product design problems within the warranty period can require the replacement of machinery and equipment. The straight-tooth drive produced by our Luoyang Longda Bearing has been researched and optimized for a long time, and the structure and product quality of the product design are reliable.

3. If the transmission is out of adjustment, adjust the calibration line and reinstall the connection between the driver and the motor, so that the rotation of the motor bearing can be stabilized.

4. The mechanical imbalance of the rotor may be due to the deviation of the rotor from the axis. The position of the rotor can be readjusted, or the design of the base can be considered. Generally speaking, the base can absorb the shock or vibration of the equipment and has a certain adhesive force. If it recurs after adjustment, only replace the base.

5. The sealing gasket can be replaced or the sealant can be applied to solve the shaking problem caused by leakage of the joint surface.

The above are the specific reasons and solutions for the shaking of the spur gear slewing drive. I hope to help you. In addition, if you have other questions when using the spur gear slewing drive, you are welcome to inquire us at Luoyang Longda Bearing Co., Ltd. We have many years of experience. The production experience of slewing reducer, slewing ring, spur gear slewing drive, if you have any needs, please feel free to inquire.

What are the oil lubrication methods for slewing bearings?

August 13, 2021/in Slewing Bearing Knowledge /by ldbadmin

The slewing bearing needs to be lubricated during use and storage. The common lubrication methods are grease lubrication and oil lubrication. The medium for grease lubrication is grease, and the oil lubrication is lubricating oil. Then, for the turntable In terms of bearings, what are the benefits of using oil lubrication? What are the oil lubrication methods for slewing bearings? The following is a summary made by the editor for everyone, let’s take a look.

The benefits of oil lubrication for slewing bearings

The slewing bearing is lubricated by oil lubrication, which can achieve good cooling and cooling effects. This oil lubrication method is very suitable for bearings with relatively high operating temperatures. The viscosity of the lubricating oil used in the bearing is about 0.12 to 0.2cm/s. If the bearing load is high and the working temperature is high, choose a high-viscosity lubricating oil, and a rolling bearing with a fast speed is suitable for a low-viscosity lubricating oil. But it should also be noted that oil lubrication requires that the bearing must be kept in a good sealing state to avoid leakage of lubricating oil. In addition, oil lubrication requires a more complicated oil supply device, so you must pay more attention to the operation and use, and pay attention to the use and maintenance of the bearing.

The method of lubricating slewing bearing oil

1. Oil bath lubrication

Oil bath lubrication is a relatively common lubrication method. It is suitable for the lubrication of low and medium speed bearings. Imported bearings are partially immersed in the groove, and the lubricating oil is picked up by the rotating bearing parts and then flows back to the oil groove. The oil level should be slightly lower than The center of the lower rolling element.

2. Dripping oil lubrication

Drip lubrication is suitable for imported bearing parts that require a quantitative supply of lubricating oil. The amount of dripping oil is generally one drop every 3-8 seconds. Excessive oil volume will cause the bearing temperature to increase.

3. Circulating oil lubrication

Use an oil pump to deliver the filtered oil to the bearing components, and then filter and cool the lubricating oil after passing through the bearing for use. Because circulating oil can take away a certain amount of heat and cool the bearing, this method is suitable for bearing parts with higher speeds.

4. Spray lubrication

Dry compressed air is mixed with lubricating oil through a sprayer to form oil mist. Injecting into the bearing, the airflow can effectively cool the bearing and prevent the intrusion of impurities. This method is suitable for the lubrication of high-speed and high-temperature bearing components.

5. Jet lubrication

Use an oil pump to inject high-pressure oil into the bearing through a nozzle, and the oil injected into the bearing flows into the oil groove through the other end of the bearing. Imported bearings have higher rated load, lower noise, greatly reduce warranty costs, increase machine running time and other advantages; when distinguishing the authenticity of such imported bearings, you can touch the steel stamp on the bearing to make it faster and more efficient. Accurately distinguishing, this kind of steel seal will not feel tactile if you touch it with your hand, but you can feel the presence of the steel seal by gently touching it with your fingernail. When the bearing rotates at a high speed, the rolling elements and the cage also make the surrounding air form an airflow at a relatively high rotation speed. It is difficult to send the lubricating oil to the bearing by the general lubrication method. At this time, the lubricating oil must be sprayed by high-pressure injection. In the bearing, the position of the nozzle should be placed between the inner ring and the center of the cage.

The above is the slewing bearing manufacturer’s summary of the oil lubrication methods for slewing bearings, the benefits of slewing bearing oil lubrication and all the common methods. We understand that oil lubrication can help the bearing achieve a good cooling and cooling effect. The oil lubrication methods include oil bath lubrication, drip lubrication, circulating oil lubrication, spray lubrication, jet lubrication, etc. You can choose according to your own reagent needs

How often is the slewing bearing maintained and how to maintain it?

August 9, 2021/in Slewing Bearing Knowledge /by ldbadmin

After the slewing bearing is used for a period of time, it is inevitable that there will be problems such as noise, vibration, and temperature rise. In this case, if you want to extend the service life of the bearing, you need to maintain the slewing bearing regularly. Then, how long is the slewing bearing? Maintenance once? What is the maintenance method? What problems should be paid attention to during maintenance? Next, the slewing bearing manufacturer will introduce the maintenance cycle and method of the slewing bearing to everyone, and I hope it will be helpful to everyone.

Slewing bearing maintenance cycle

How often is the slewing ring bearing maintained? The maintenance time of slewing bearings is the same as that of ordinary bearings. Theoretically, they can be used for 20000-80000 hours, but the specific life depends on the wear during use, work intensity and later maintenance, etc., among which maintenance is an important part of prolonging the service life of the bearing. ring.

Maintenance method of slewing bearing

1. Clean the slewing bearing

Cleanliness has a considerable impact on the life of the slewing bearing. The higher the cleanliness of the bearing, the longer the life. Lubricants with different cleanliness have no effect on the life of the bearing. Therefore, improving the cleanliness of the lubricating oil can prolong the life of the bearing. In addition, if the dirt particles in the lubricating oil are controlled below 10um, the life of the bearing will also increase several times. So, how should the specific bearing cleaning be done? We then look down.

(1) The cleaning of the bearing is divided into rough cleaning and fine cleaning, and a metal grid can be placed on the bottom of the container in use.

(2) For rough washing, use a brush to remove grease or adhesions in oil. At this time, if the bearing is rotated in oil, be careful that the rolling surface may be damaged by foreign matter.

(3) During the fine washing, slowly rotate the bearing in oil, which must be carried out carefully. Commonly used cleaning agents are neutral non-water-containing diesel or kerosene, and sometimes warm lye etc. are used as needed. No matter what kind of cleaning agent is used, it must be filtered frequently to keep it clean. After cleaning, immediately apply anti-rust oil or anti-rust grease on the bearing.

2. Derusting bearings

(1) Soaking method: Some small items are immersed in anti-rust grease, and the cross tapered roller bearing is coated with a layer of anti-rust grease on the surface. The thickness of the oil film can be achieved by controlling the temperature or viscosity of the anti-rust grease.

(2) Brushing method: used for outdoor construction equipment or products with special shapes that are not suitable for immersion or spraying. When brushing, it is necessary to pay attention not to accumulate, but also to prevent leakage.

(3) Spray method: Some large anti-rust objects cannot be oiled by immersion method. Bearings are generally sprayed in clean air with filtered compressed air with a pressure of about 0.7Mpa. The spray method is suitable for solvent-diluted anti-rust oil or thin-layer anti-rust oil, but complete fire protection and labor protection measures must be adopted.

3. Bearing lubrication

(1) Manual lubrication: This is a relatively primitive method. When the lubricating oil of the bearing is insufficient, use an oiler to supply oil. However, this method is difficult to maintain a certain amount of oil. It is more dangerous to forget to refuel due to negligence. It is usually only used in light-load, low-speed or intermittent sports. It is recommended to install a dust cap or ball valve on the refueling hole and use it. Felt, cotton, wool, etc. are used as filter devices.

(2) Dropping point lubrication: usually used for light-load and medium-load bearings with a peripheral speed of less than 4~5m/s. A roughly fixed amount of lubricating oil is supplied from the container through holes, needles, valves, etc., the more classic is dripping oil Cup, the amount of dripping oil varies significantly with the viscosity of the lubricating oil, the bearing clearance and the position of the oil supply hole.

(3) Oil ring lubrication: The lubricating oil from the oil pool is brought to the bearing by the ring that is hung on the shaft and can rotate (only for the lubrication method of the horizontal shaft), suitable for medium and high speed shaft diameters greater than 50mm Bearings and oil rings are recommended to be seamless. When the bearing width-to-diameter ratio is less than 2, only one oil ring can be used, otherwise two oil rings are required.

(4) Oil rope lubrication: Relying on the capillary and siphon action of the oil rope to guide the lubricating oil in the oil cup to the bearing, it is mainly used for light-load and medium-load bearings with a peripheral speed of less than 4～5m/s. Can play a filtering role in the whole process.

(5) Oil pad lubrication: Use the capillary action of the oil pad to apply the lubricating oil in the oil pool to the surface of the shaft diameter. This method can keep the friction surface clean, but dust will also block the pores and cause insufficient oil supply. The oil supply of oil pad lubrication is usually only 1/20 of oil lubrication.

Precautions for maintenance of slewing bearings

1. Precautions for cleaning

(1) Qualified new bearings are not cleaned: New bearings that have passed inspections may not be cleaned under normal operating conditions (motors with more than 2 poles); new sealed bearings are not cleaned.

(2) Clean before oil change: The bearing cap and bearing must be cleaned before oil change. The cleaning is divided into rough washing and fine washing. The oil for rough washing is clean diesel or kerosene, and the oil for fine washing is clean gasoline.

(3) Inspection during cleaning: After the bearing is cleaned, turn it by hand and shake it radially and axially by hand to determine whether it is loose or the gap is too large. Check the gap if necessary. If the ball or roller frame is found to be severely worn, rusted, and metal peeling, it should be replaced.

(4) Wipe dry and grease after cleaning: After the bearing is cleaned and inspected, wipe the cleaning agent (or dry) with a white cloth, and add qualified grease. It is not allowed to add different types of grease in the same bearing.

2. Precautions for rust removal

(1) Selection of derusting liquid: Note that the following acid liquids cannot be used for bearing derusting: sulfuric acid, hydrochloric acid, dilute sulfuric acid, and dilute hydrochloric acid. Because these acid liquids will destroy the good metal parts, these kinds of liquids cannot be used!

(2) Selection of rust removal methods: I have introduced several common rust removal methods above, including soaking method, brushing method, spraying method, etc. You can choose according to the actual situation of the bearing, but no matter which method it is It is necessary to pay attention to the protection of the bearing during operation. The damage to the bearing due to maintenance is more than the loss.

3. Precautions for lubrication

(1) No dust in the surrounding environment when refueling: refuel with clean hands, slowly rotate the entire bearing with one hand, and press the oil into the bearing gap with the middle finger and index finger of the other hand. After adding one side, proceed to the other side to remove excess grease.

(2) Bearing and bearing cap refueling volume: The bearing cap oil volume is 1/2-2/3 of the bearing cap capacity (the highest number of poles of the motor is the upper limit); the bearing oil volume is 1/2-2/3 of the cavity of the inner and outer rings of the bearing ( The number of motor poles is higher than the upper limit).

The above is about how often the slewing bearing is maintained, the maintenance cycle and the entire content of the method. We understand that the general slewing bearing is maintained every 20000-80000 hours. The specific time needs to be determined according to the actual situation. The maintenance method includes regular cleaning, which is effective. Rust, reasonable lubrication, etc. It can be seen that if you want to extend the service life of the slewing bearing, you still need to work harder and maintain it.

What is the manufacturing process of slewing bearings

August 6, 2021/in Bearing Knowledge, Slewing Bearing Knowledge /by ldbadmin

Slewing ring bearings are also called slewing bearings. The main structure includes: inner ring, outer ring, rolling elements, and rolling element-guided cages. They are important transmission components in mechanical equipment. They are used in engineering machinery, light industrial machinery, metallurgical machinery, medical machinery, Ship equipment and other industries are widely used. Next, the slewing ring manufacturer will take you to understand the manufacturing process and detailed steps of the slewing ring.

1. Cutting of slewing bearing steel material

The commonly used raw material for slewing bearings is integrally hardened carbon-chromium bearing steel, and the slewing ring is made of surface hardened steel, generally made of 50Mn steel, such as: S48C, 42CrMo, 5CrMnMo. The cylindrical raw material billet transported back from the steel mill is cut according to the size required for processing the bearing. Generally, carbide saw blades should be used for cutting bearing steel, which have high hardness, wear resistance, strength and toughness, heat resistance, corrosion resistance, etc. A series of excellent properties.

2. Slewing bearing billet forging

In the heating furnace, the billet is heated and forged into a round cake shape. The forging link is an important link to ensure the reliability and life of the bearing. After the raw material is forged, the bearing ring blank is formed. At the same time, the organization structure of the raw materials becomes denser and the flow linearity becomes better, which can improve the reliability and service life of the bearing. In addition, the quality of the forging process will directly affect the utilization rate of raw materials, thereby affecting production costs.

3. Slewing ring forged ring

The steel blank is forged into a ring-shaped steel ring using a ring rolling machine. Forging can improve the internal structure of steel and improve the strength, plasticity, impact toughness and other mechanical properties of steel.

4. Rough turning processing

The steel ring after the ring is put into the machine tool, and the rough turning of machining is performed, and various groove raceways are turned out, and the steel ring is fixed on the gear milling machine to cut teeth. The main purpose is to make the shape of the ferrule after the final product the same, creating conditions for the later grinding machine processing.

5. Slewing bearing quenching (heat treatment)

After machining, through quenching operation, the strength and hardness of the steel are improved, and the wear resistance, fatigue strength and toughness of the metal are improved. The heat treatment process is to subject the forged and machined bearing ring to high temperature treatment, which directly affects the uniformity of carburization in the bearing ring, improves the wear resistance and hardness of the bearing, and also affects the reliability and life of the bearing. Important link.

6. Hole processing of slewing bearing

Drill the mounting hole on the end face of the steel ring. When opening the slewing bearing bearing, determine the center and cutting angle. Choose a drilling machine, hand-held electric drill and hand drill for operation.

7. Fine grinding

Finishing is to trim the fine parts of the bearing roughly formed after the hole is opened to ensure the refinement of the appearance. Finishing has an effect on the rotation flexibility of the bearing and the precision of the bearing surface. Once again, the raceway surface of the steel ring is finished. Modify the deformation caused by the previous process.

8. Slewing bearing assembly operations

Assemble the parts (outer ring, inner ring, roller, cage) processed through various processes, such as inserting steel balls, spacer blocks, and inserting butter sealing strips. Assemble a set of finished bearings according to different technical and precision requirements.

9. Slewing bearing finished packaging

The finished bearing will be coated with anti-rust oil, packaged and packaged. At the same time, it will be sampled and inspected by the factory inspector, and the qualified products will be issued with a certificate, and then sold.

The above is the related content of the slewing bearing manufacturing process and production operation specifications introduced by the slewing bearing manufacturer, including the selection of slewing bearing material cutting, forging, turning processing, heat treatment, grinding processing, assembly and other related content for your reference.

What material is good for the slewing bearing and how should it be selected?

August 2, 2021/in Slewing Bearing Knowledge /by ldbadmin

The material of the slewing bearing directly determines the performance and service life of the bearing. At present, the main structure of bearings on the market is mostly made of bearing steel, which has the characteristics of corrosion resistance and stability. Of course, in addition to bearing steel, there are also metal materials such as aluminum alloy or copper. In addition, the sealing ring and cage of the bearing may be different from the material of the main body of the bearing. The following slewing bearing manufacturers will share what material is good for the slewing bearing.

What material is good for the slewing bearing?

1. Material of ferrule and rolling element

The early slewing bearing used 45# steel, but it was gradually eliminated due to poor modulation performance in the later period. In the current more common processing technology, the slewing bearing rolling element adopts integrally hardened carbon chromium bearing steel. The grade is made of GCr15 or GCr15SiMn steel; the ring of the slewing bearing is made of surface hardened steel, and if there is no special requirement, it is made of 50Mn steel. But sometimes customers also choose to customize other grades such as 42CrMo, 40Cr, etc. The following describes the characteristics of these grades of steel.

(1) As a high-carbon steel, 42CrMo has good quenching and quenching properties and is an ideal material for slewing bearings.

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

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

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

2. Material of cage

Cages for slewing bearings have structural forms such as integral, segmented, and isolated block types. The types of cage materials are: low carbon steel stainless steel cage, bakelite/plastic (nylon) cage, brass/bronze/aluminum alloy cage, etc. The spacer type is made of polyamide 1010 resin, ZL102 cast aluminum alloy, etc. .

The characteristics of various material bearing cages are as follows:

(1) Steel bearing cage: It is often cold stamped from 08 and 10 carbon steel sheets. Commonly used steel cage materials include 20, 30, 45, 0Cr18Ni9, 1Cr18Ni9Ti, 40CrNiMo, ML15, ML20, etc., which are commonly used materials in bearing cages, which are solid, durable and stable.

(2) Non-ferrous metal bearing cage: Different from steel, non-ferrous metal has its special properties. For example, aluminum alloy has the characteristics of low density, good thermal conductivity, and good corrosion resistance; copper alloy has good thermal conductivity, low friction coefficient, Features such as good formability and high use temperature; zinc-aluminum alloy has the advantages of low cost, low density, and excellent performance.

(3) Non-metallic cage: non-metallic cage materials mainly include polymers and their composite materials, including nylon, phenolic tape, polytetrafluoroethylene, etc. The polymer material has good strength and elasticity matching, which can effectively reduce the heating and wear of the bearing.

3. Material of sealing ring

Bearing sealing materials are generally commonly used sealing materials, mainly: nitrile rubber, silicone rubber, fluorine rubber, EPDM, fluorobutadiene rubber, polytetrafluoroethylene, polyurethane rubber, acrylic rubber, Anaerobic glue, etc.

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

How to choose the material of the slewing bearing

The slewing bearing manufacturer said that the materials used in slewing bearings should be analyzed based on the current level of slewing bearing production technology. It is recommended that the materials of bearing rings, rolling elements, cages, and sealing rings should first consider the following materials.

1. Material of rolling element: GCr15SiMn is generally used for rolling element.

2. Ring material: 50Mn is used for the slewing bearing ring, but sometimes 42CrMo is used to meet the needs of the host in special applications.

3. Cage material: The cage has different structure types such as integral type, segmented type and isolated block type. The integral or segmented retainer adopts 20# steel or ZL102 cast aluminum alloy. The isolating block holder adopts polyamide 1010 resin, ZL102 cast aluminum alloy or QA110-3-1.

4. Sealing ring material: The slewing bearing should be made of oil-resistant rubber, fluorine-containing rubber, and oil-resistant nitrile rubber. The clearance of the slewing bearing The clearance of the slewing bearing is mainly used to compensate the manufacturing error and installation error of the slewing bearing supporting parts and the relevant host assembly parts to ensure the normal use of the bearing. According to the structure type/tolerance class of the slewing bearing and the pitch circle diameter of the rolling element group, the clearance value or the interference amount of the slewing bearing.

The above is the introduction of the slewing bearing manufacturer on the material of the slewing bearing. The bearing materials mentioned are all suitable for slewing bearings, but the specific use environment and performance requirements may have different requirements for the bearing materials. Please follow the actual situation. Choose the situation.