How to judge the operating status of the slewing drive? Common faults and solutions

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Slewing drives are widely used due to their modular installation convenience, operational stability, load-bearing capacity and strong environmental adaptability, etc., to improve industrial production efficiency and accelerate the realization of industrial automation. Then, once a failure occurs during the operation of the equipment, it may affect the normal production plan. For this reason, we should pay attention to the operation of the equipment and make timely judgments.

Judgment method of slewing drive operating state

SE Series Slewing Drive

1. Pay attention to the backhaul gap

During the operation of the equipment, observe the clearance of the rotary reducer during the return stroke, and judge the return clearance of the drive by the instant forward and reverse operation mode during operation. Refer to the theory of the type of rotary reducer corresponding to the instruction manual provided when the drive is purchased. The return gap can be used to judge whether the running state is normal.

2. Listen to the running sound

Normal equipment operating sounds are different from abnormal sounds. How to determine the operating status of the slewing drive can start from identifying the abnormal sounds. For abnormal noises or irregular sounds during operation, it is necessary to judge whether the reducer is in normal operation. If there are abnormal sounds, it should be repaired in time to determine the damage location and repair it.

3. Observe the operating temperature

If the slewing drive has abnormal temperature, there may be problems with overload operation or bearing wear and abnormal voltage, but these are usually not directly reflected from the operating state when the equipment is running, so we can judge by the temperature of the drive during operation. If the temperature is too high, it needs to be overhauled in time.

If all the above conditions are normal after running for more than 30 minutes, it means that the rotary reducer is in good working condition and can be used with confidence. So, the following editor introduces some common faults of rotary reducers for reference only.

Common faults and solutions of slewing drive

S Series Slewing Drive

1. The motor does not rotate: the motor does not rotate. Eliminate power failure and poor switch contact. There may be problems such as abnormal voltage, gear damage, overload operation, coil breakage, etc. You need to check the power supply, wiring, voltage, capacitor or directly contact the manufacturer for repair.

2. Abnormal heating: Abnormal heating of the drive may be caused by overload operation, abnormal voltage, bearing wear, etc. It is necessary to reduce the load and frequency of use, confirm whether the voltage is normal and perform maintenance.

3. Noise: The noise of the rotary reducer may have bearing damage, gear wear, or foreign matter jamming, and it needs to be disassembled and repaired by the manufacturer’s service personnel. Or there is lubricating oil contaminated or lack of lubricating oil, it should be supplemented or replaced in time.

4. Abnormal vibration: abnormal vibration caused by loose screws or wear of gears and bearings requires screw progress or replacement and maintenance of gear bearings.

5. Oil leakage: There are reasons such as loose screws or damage to the sealing ring, and the screws should be replaced or tightened in time.

The above are several judgment methods of Lunda editor on how to judge the running status of the slewing drive, as well as the common faults and solutions of the equipment. I hope it will be helpful to everyone. In the daily use of the reducer, you should pay attention to the running status of the equipment and find the problem in time. Repairs to prevent the deterioration of the problem from affecting production.

How to install the slewing drive? Installation method and process

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The installation of the slewing drive device directly determines its fluency during the operation of the machine and the probability of failure during use. Improper installation may cause damage to it and affect its service life. Therefore, the installation is very important for the slewing drive. I don’t know how much you know about how to install the slewing drive.

Slewing drive installation tool

1. Auxiliary tools for hardware removal and installation such as wrenches, pliers, bolt tighteners, etc.;

2 Cleaners such as diesel, banana water, gasoline, etc.;

3. Scraper (used to clean up impurities on the supporting surface);

4. Feeler gauge, used for measurement in the later installation process;

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Preparation before installation

1. Before installation, confirm whether the motor and the slewing drive are intact, and check whether the dimensions of the parts connected to the slewing drive match.

2. Screw on the screw on the dust-proof hole on the outside of the rotary drive flange, adjust the PCS system clamping ring to align the side hole with the dust-proof hole, and insert the inner hexagon to tighten. Then remove the motor shaft key.

3. Before installation, wipe the motor input shaft, positioning boss and the anti-rust oil at the connection part of the reducer with gasoline or zinc-sodium water.

4. Clean the impurities on the support surface (for example, iron filings, burrs, paint, welding slag, etc.).

5. Clean the anti-rust oil on the mounting surface of the rotary reducer.

6. Remove the transportation bolts.

Installation method

1. Fix the rotary reducer on the bracket with bolts, and install flat washers and spring washers on the bolt heads. The rotary reducer should be installed without load.

2. In order to avoid internal stress and installation problems caused by tightening the bolts, please add thread fastening glue to the threads; pre-tightened bolts and washers should be tightened crosswise; starting from the inner or outer ring, all bolts will be diagonal Tighten to 30% of the tightening torque, then tighten the diagonal to the tightening torque of the angle of 30%, and then tighten the diagonal to the mounting bolt, and do not leak. If the bolts cannot be fixed with bolts under structural constraints, the bolt holes must be sealed.

3. If filled with silica gel, it will leak water and dust into the rotary reducer. The installation bolts should consider the thread engagement length, which should not be too long, otherwise it will affect the rotation. Support rotation or cause interference; after tightening the bolt, mark the bolt head and its joint to facilitate future inspection of whether the bolt is loose.

SE Series Slewing Drive

The specific installation process

1. Clean the mounting bracket, remove welding slag, zinc plating residue, etc.;

2. Fix the bracket and the rotary reducer with bolts, and the bolt heads should be equipped with flat washers and spring washers;

3. The rotary reducer should be installed under no load.

4. Add thread fastening glue to the thread;

5. The pre-tightened bolts and washers should be tightened crosswise; the bolt tightening sequence is shown in the figure below; starting from the inner ring or outer ring, all bolts are tightened diagonally to 30% tightening torque, and then repeated diagonally to 50 % Tightening torque, tighten diagonally to 100% tightening torque.

6. The installation bolts are all on top, and no missing installation is allowed. If the bolts cannot be installed due to structural restrictions, the bolt holes must be sealed, such as filled with silica gel, otherwise water and dust will leak into the rotary reducer;

7. The thread engagement length should be considered for the installation bolts, and should not be too long, otherwise it will affect the rotation of the slewing ring or cause interference;

8. After the bolts are tightened, please mark the bolt heads and the joints, which is convenient for checking whether the bolts are loose in the future;

9. Repainting: During the installation of the rotary reducer, it will inevitably cause surface paint bumps and damage. Therefore, after the system is assembled, the rotary reducer needs to be repainted to improve the anti-rust and anti-corrosion capabilities.

After reading the installation method of the slewing drive and the specific installation process, everyone should have a certain understanding of how to install the slewing drive, so let’s take a look at some of the work after the slewing drive is installed.

Maintenance, inspection and lubrication after installation

1. Maintenance and inspection

After the initial assembly is used for about 100 hours, it is necessary to re-tighten the bolts to the specified tightening torque; this inspection needs to be carried out once a year. Under special operating conditions, the number of inspections is relatively reduced. After the bolts are loosened, please replace all bolts, nuts and washers immediately.

2. Lubrication

Lubrication of rotary reducer: The important parts of the product have been lubricated before leaving the factory. We will decide whether to add lubricating ester according to the actual situation during installation. The slewing ring raceway has been filled with grease before leaving the factory; the worm and the slewing ring need to be refilled with grease before use; the tapered roller bearing has been filled with grease before leaving the factory.

HSE Slewing Drive Gearbox

Installation precautions

1. Installation plane

The surface on which the rotary drive is installed should be kept smooth and clean, and the excess materials on it, such as paint residue, welding beads, burrs, etc., should be cleaned. At the same time, the installation surface should be dry and free of lubricant. Specifically, it is necessary to keep the mounting surface roughness of the mounting support not greater than Ra=12.5, 6.3μm. In order to avoid the unevenness of the mounting surface or the deformation of the support causing local overload of the rotary drive, the circumferential flatness error is within any range of 180 degrees. There can only be one wave ups and downs inside, and the changes are gentle.

2. The stiffness of the support

Standard slewing drive and zero-clearance slewing drive have different requirements for the rigidity of the support. Therefore, during installation, a support with corresponding rigidity should be selected according to the specific rotary drive.

3. Positioning

Both the inner and outer ring raceways of the slewing drive have a soft belt, which should be placed on both sides of the main load plane. That is 90 degrees staggered from the main load zone. There is a blockage or “S” mark on the soft belt. In addition, check the fit between the rotary drive and the mounting surface, usually with a feeler gauge. If the fit is not good, fill it with appropriate materials. It is forbidden to weld on the support after the rotary drive is installed.

4. Fastening bolts

Use the specified bolts, and do not use full-threaded bolts, do not use old bolts, nuts and washers, and prohibit the use of open washers such as elastic washers.

After reading this article, I believe that everyone has a certain understanding of how to install the rotary drive. During the installation process, the installation process and precautions must be strictly followed. At the same time, do not forget to check after the installation is completed.

What is the installation process of spur gear drive?

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Slewing drive is divided into spur gear slewing drive and worm gear slewing drive. Spur gear slewing drive is also called spur gear drive, gear slewing drive, and gear slewing reducer. Its main applications include solar and wind power generation equipment, robots, radar, low-speed heavy-duty lifting, lifting equipment, precision CNC turntables and other products.

Application principle of spur gear drive

Spur gear drive is a full-circle reduction transmission mechanism that inherits the driving power source. Its working principle is to use all levels of gear transmission to achieve the purpose of speed reduction. The spur gear slewing drive uses a slewing ring as a drive follower and a mechanism attachment. By attaching a driving part and a driving source to one of the inner and outer rings of the slewing ring And the cover, and the other ring is used as the driving follower and the connecting base of the driven working part. In this way, the slewing bearing itself is a full-circle slewing connector, and the driving power source and main transmission parts are configured. Rotary drive is such a general-purpose reduction transmission mechanism that integrates the functions of rotation, speed reduction and driving.

Installation method of spur gear drive

1. Open the package of the slewing drive, check the certificate and label, and confirm that the type of slewing drive used is correct.

2. Make sure to install under no-load conditions, and level the installation position after keeping the surface of the equipment clean.

3. After leveling, install the rotary drive on the equipment support using a wrench, and level the equipment again. The circumferential flatness error can only have one wave ups and downs within any range of 180 degrees, and the change is gentle.

4. Position the equipment and place the soft belts on the inner and outer ring raceways of the slewing drive on both sides of the main load plane. That is 90 degrees staggered from the main load zone. There is a blockage or “S” mark on the soft belt.

5. Tighten up after positioning, use a feeler gauge to measure the fit between the rotary drive and the mounting surface. If the fit is not good, fill it with appropriate materials.

6. Adjust the gear backlash. Use a feeler gauge to measure and adjust the gear radial runout point. If the backlash is not within the specified value, move the pinion to change the center distance, and mark the gear radial runout point in the tooth groove with green paint. .

7. After installation, lubricate the supporting slewing drive, including raceways and gears. In order to ensure sufficient lubrication, the grease specified in the drawing or product instruction manual should be refilled before the first use.

Installation precautions

1. Before installation, confirm whether the motor and gear slewing drive are intact, and check whether the dimensions of the parts connected to the slewing drive match.

2. Screw on the screw on the dust-proof hole on the outside of the rotary drive flange, adjust the PCS system clamping ring to align the side hole with the dust-proof hole, and insert the inner hexagon to tighten. Then remove the motor shaft key.

3. Before installation, wipe the motor input shaft, positioning boss and the anti-rust oil at the connecting part of the speed reducer with gasoline or zinc-sodium water.

4. After the rotary drive is installed, it can be turned by hand, and the application is flexible without jamming. Before starting the machine, fix the connecting screws. The no-load test run should be no less than 2 hours, and the operation should be stable, without impact, vibration, noise and oil leakage. If found, it should be eliminated in time. When using, check whether the fasteners are loose. Ensure normal operation.

5. Naturally connect the motor and the reducer. When connecting, it must be ensured that the output shaft of the reducer and the input shaft of the motor are concentric, and the outer flanges of the two are parallel, so as to extend the service life and obtain the ideal transmission efficiency and comparison. Low noise. In addition, do not hit with a hammer during installation to prevent excessive axial or radial force from damaging the bearings or gears. Be sure to tighten the mounting bolts before tightening the tightening bolts.

The above is the whole content of the spur gear drive application principle, installation method and precautions. Spur gear drives can be used in fields that require high precision such as CNC machine tools and military radars. If you have any questions during the installation or use of the spur gear drive, please call for consultation or leave a message.

What happens if the slewing bearing is improperly lubricated?

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When buying slewing bearings, slewing bearing manufacturers will tell us to lubricate the bearings regularly, but for those who don’t understand, improper lubrication may occur during lubrication. Then, are the consequences of improper lubrication of slewing bearings serious? ? What happens if the slewing bearing is improperly lubricated? What should be paid attention to when lubricating bearings?

Consequences of improper lubrication of slewing bearings

Slewing Bearings

1. Discoloration

Metal-to-metal contact will make the bearing temperature too high, causing the raceways and rollers to become discolored. In mild cases, this discoloration is due to the lubricant contaminating the bearing surface, while in severe cases, the metal discolors due to high temperatures. In all cases, early detection can avoid costly repairs.

2. Bearing heating

When the machine is running, the part where the bearing is installed is allowed to have a certain temperature. When touching the housing of the mechanism with your hand, it should be normal that you don’t feel hot, otherwise it indicates that the bearing temperature is too high. One of the reasons for excessively high bearings is poor lubrication of the bearings. The lubricating oil (or grease) used in rolling bearings has a certain working temperature. When the temperature is too high, water or ash enters the bearing seat, it will be seriously oxidized, emulsified, etc., which will lose its lubrication effect and cause the bearing to suffer from high temperature. And burned. In addition, poor quality of lubricating oil (or grease) itself or failure to add oil (grease) during operation will cause the bearing temperature to rise.

3. Scratches and peeling

Inspect the bearing for signs of cutting into the metal or peeling of the metal. These situations require immediate attention. Scratches and peeling are prone to occur in high-load low-speed applications or continuous high temperatures, and thin or insufficient lubricating oil film will accelerate the occurrence of the problem. Insufficient lubrication, wrong grease selection, or sudden changes in working conditions may cause bearing material to peel off or bearing ribs to scratch.

4. Abnormal bearing noise

If the bearing is in a good state of continuous rotation, it will emit a low whining or buzzing sound. If there is a sharp hiss, squeak and other irregular sounds, it often indicates that the bearing is in a poor continuous rotation condition. The sharp squeaking noise may be caused by improper lubrication.

5. The bearing is completely locked

Extreme local heating will produce metal flow in the bearing, changing the original material and geometry of the bearing. This may result in excessive tilting of the rollers, damage to the cage, and complete lock-up of the bearing. If catastrophic damage does occur, it is recommended to consult a bearing expert to determine the root cause of the problem, because it may be a factor other than lubrication.

Precautions for correct lubrication

Slewing Bearings

1. Choose the right grease

Choosing a suitable grease will make the grease fully play the role of lubrication in the bearing operation, so that the bearing can be used for a longer time. The following are the points that need to be paid attention to when choosing the grease. Let’s take a look.

(1) Look at the working temperature: The working temperature of the lubricating part is an important basis for choosing lubricating grease. The typical components that use grease are rolling bearings. Under high temperature conditions, the temperature of the outer ring of the bearing is 15°C lower than the temperature of the inner ring. The temperature of the bearing operating at medium and low speeds (3000-5000r/min) is similar to the temperature of the internal medium. Under low temperature conditions, synthetic oil grease must be used, especially for some instrument miniature bearings, which have a small aerodynamic torque. Pay special attention to the selection of grease.

(2) Look at the running speed of the bearing: the speed of the lubricating component has a great influence on the bearing life of the grease. Therefore, when selecting lubricating grease, the movement speed of the lubricated part must be considered.

(3) Look at the environment: the environment of the lubricating part and the medium in contact have a great influence on the performance of the grease.

(4) Look at the filling method: the filling method of grease includes manual filling and centralized pump filling. Smearing or filling, grease gun filling, grease cup filling, etc. are manual filling and automatic filling.

2. Choose the right way

(1) Manual lubrication: This is a relatively primitive method. In the case of insufficient lubricating oil in the bearing, use an oiler to supply oil. It is usually used for light-load, low-speed or intermittent motion occasions. It is recommended to use the oil filler hole during operation. Dust cover or ball valve is set on it, and felt, cotton, wool, etc. are used as filter devices.

(2) Automatic lubrication: The automatic lubricator is a device used to replace manual refueling. The main advantage of this device is to save labor. It can refuel regularly and quantitatively, so that the life of the equipment can be prolonged, especially suitable for more complicated working conditions. Bottom, can reduce the safety risk of manual refueling. Using an automatic lubricator, you can continuously lubricate the running equipment automatically.

3. Add grease in time

Choosing the appropriate grease and lubrication method is the prerequisite for lubrication, but it is also necessary to add grease in time in daily use. This is also a problem that people often ignore or forget. Adding grease in time is to ensure that the bearing is running to meet the operating conditions Lubricating oil, which is also the key to extending the service life of the bearing.

The above is the whole content of the consequences caused by improper lubrication of the slewing bearing and the lubrication method. We understand that improper lubrication of the slewing bearing may cause the bearing to change color, heat, scratch and peel, have abnormal noise, lock up, etc. When lubricating, pay attention to the correct selection of grease and timely add grease, etc., which can effectively avoid the occurrence of improper lubrication.

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

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The slewing bearing is an indispensable part of large-scale machinery. It can be installed in the machine to allow the machine to rotate left and right. At the same time, it can withstand various forces. Because the slewing ring is very important, careful maintenance is required. More than 96% of the slewing ring failures are caused by lubrication problems, pollution, wear and incorrect operation, which seriously affects its service life and normal performance.

1. The slewing bearing is coated with a small amount of grease when it leaves the factory. When the product is used, it should be filled with new grease according to different working conditions.

2. The slewing bearing should be greased regularly. According to different types of slewing bearings, the specific grease filling time is as follows:

a: Ball type: Grease is added once every 100 hours of operation.

b; Roller type: Grease is added every 50 hours of operation.

Slewing Bearings

If in a special working environment, such as: tropical, high temperature, dusty, high temperature and continuous continuous work, the grease filling cycle should be shortened, and the grease should be filled once every 50 hours of work; when the gear is working normally, it should be guaranteed to work every time Apply detergent once every 150 hours. When working vigorously, apply detergent once every 75 hours of work. Note that the teeth must be wiped clean before applying detergent. The machine must be refilled with new grease before and after the long-term stagnation of the machine. Each time the grease is added, the raceway must be filled until it overflows from the sealing device. When the grease is added, the slewing ring must be slowly transferred. Make the grease evenly filled in the raceway.

3. Because there are many comprehensive factors in the process of use, the user can choose the grease according to the specific situation. For example, the raceway can use: No. 3, No. 4 graphite grease, industrial grease, No. 203 grease, No. 7002 High and low temperature bearing grease and No. 2 aluminum-based grease, etc.

Since the slewing ring is installed, after 100 hours of operation, the pre-tightening force of the bolts should be checked, and every 500 hours of operation thereafter, it must be adequate and tried.

4. After the equipment has been working for 2000 hours, if a bolt is found to be loose below 80% of the specified torque, the bolt and two adjacent bolts shall be replaced with new ones; if 20% of the bolts are found to be loose to 80% of the specified torque Below, all bolts are replaced with new ones. After the equipment has been working for 14,000 hours, all bolts should be replaced with new ones.

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5. Pay close attention to the operation of the slewing bearing during use. If you find that the noise, impact, or power suddenly increases, you should stop the machine for inspection immediately until all the faults are eliminated, and disassemble and inspect if necessary.

6. When the slewing bearing is in use, it is forbidden to directly wash the slewing bearing with water to avoid water entering the raceway to cause rust; strictly prevent hard foreign objects from approaching or entering the meshing area to avoid injury to the teeth or unnecessary trouble.

7. To keep the surface of the slewing bearing clean, choose a suitable solvent for cleaning according to the surface properties of the rust-proof object, so as to avoid serious corrosion. Surface cleaning can use chemical treatment cleaning method and mechanical cleaning method. When the surface is dry, do a good job in controlling the temperature and wait until most of the area is dry before wiping it with gauze. When applying anti-rust oil, it is necessary to apply different methods according to the different properties of the bearing surface. Miniature bearings can be directly immersed in anti-rust grease. If you encounter a special shape, you can choose the painting method, so that it is not easy to produce accumulation. There are many factors that cause metal corrosion. The chemical composition of the metal itself can also cause corrosion or the temperature and humidity of the environment in which the item exists can also cause corrosion.

8. The sundries on the surface of the slewing ring should be removed frequently during use, and the sealing strips of the slewing ring should be checked for aging, cracking, damage or detachment. If one of these conditions occurs, the sealing strips should be replaced in time to prevent debris and debris from entering the raceway. If the grease is lost, the corresponding grease should be applied after replacement to avoid jamming or rusting of rolling elements and raceways.

The above is a detailed explanation of the maintenance work in the use of the slewing ring. In short, the slewing ring has malfunctions such as noise and impact after a period of use. The operator should pay attention to observe and check in time to eliminate the fault. Only correct and reasonable maintenance of the slewing bearing can ensure its normal operation, give full play to its performance, and extend its service life.

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

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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

VE Series Slewing 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.

SDE-PDE SERIES SLEWING DRIVE

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

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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

Slewing Bearings

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

Slewing Bearings

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?

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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

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

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?

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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

HSE Slewing Drive Gearbox

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?

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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

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.

Slewing Bearings

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.