The structure and function of the slewing drive of the truck-mounted crane

Slew Drive

The structure and function of the slewing drive of the truck-mounted crane

Slew Drive Structure

The slewing drive device of the truck-mounted crane includes a hydraulic motor, a brake and a reducer.


1.Hydraulic Motor

Convert the pressure of hydraulic oil into rotational mechanical energy and transmit the rotational motion to the reducer.


The brake is inside the hydraulic motor and brakes the output shaft of the hydraulic motor.


The reducer of truck-mounted crane is composed of a two-stage reduction planetary gear transmission. It is decelerated through the gear transmission device and transmitted to the output shaft of the reducer.

Slewing Bearing

Abnormal noise problem of excavator slewing bearing

It is normal for the new slewing bearing to make a uniform sound of rolling steel balls when it is idling. It will disappear after a period of running-in after installation. If there is a loud sound or special noise, you should pay attention.

1. The mounting surface is uneven and the mounting bolts are loose

2. There is a foreign body in the slewing bearing

3. Abnormal noise caused by a problem with the grease

4. Raceway and rolling body are severely worn

Conclusion: you should not be careless when there is abnormal noise in the excavator slewing bearing, you must check and solve the fault in time.

Slewing Gear Ring Bearing Drive

Slewing Gear Ring Bearing & Slewing Gear  Drive

Rotary gears are usually divided into two types, one is the rotary gear support bearing, the other is the rotary gear drive
Slewing gear support bearings are composed of an inner ring and an outer ring, usually one of which contains the gear. Together with the connecting holes on the two rings, they are easily and quickly wired through the adjacent link components for optimized power transmission. Slewing gear bearing raceways combined with rolling elements and cages are designed to withstand loads acting individually or in combination in any direction.
Rotary gears can be used in various industries such as aerospace, heavy equipment, industrial machinery, medical systems, mining, oil and gas, etc., and are the key to many industries and play a vital role.
The slewing gear support bearing is different from ordinary bearings, the difference is that it has a gear that can adjust the rotation. The machine transmits and adjusts the direction of the mechanical products fixed on the slewing bearing through the dynamic sensing system installed on the slewing gear bearing. and take advantage of special constructs:

It maintains the overall balance, effectively guarantees the radial force generated in the work, and ensures the balance.

The rotary gear drive is a kind of turntable fixed in the gear box, which can safely bear the radial and axial load force, and drives the rotation of the turntable through the rotation of the turbine. Rotary gear drive is a gearbox composed of gears, bearings, seals, casings and motors.
The rotary gear drive is a modification of the worm drive mechanism. It dates back to the Renaissance period, when the Greek mathematician Pappus devised a worm drive. Da Vinci also used the slewing gear drive trim in many of its machines.

The driving force of the rotary gear drive comes from the rotational force given by the motor to the worm, and the gear on the worm is adjusted by the gear on the electric turntable. This combination mode reduces the rotation speed of the turntable, increases the torque, and can drive heavier objects.
Slewing gear drives can be applied to solar trackers, wind turbines, elevators, hydraulic machinery, telescopic arms, cranes and other equipment.

Slewing Bearing Installation Surface

Mechanical machining of the bearing connection surfaces on the connecting structure is required . The mounting position of slewing bearings must correspond to that shown in the drawing. If a transporting cross was delivered, it has to be removed before installation.

The corrosion protection can be removed with an alkaline cleaner. Cleaner must be prevented from coming into contact with the seals or the raceway. Remove the protective coating from the upper and the lower mounting surfaces of the slewing bearing as well as from the gear.

The corrosion protection can easily be removed, for example, using a biodegradable alkaline cleaner.

Rapid removal of the corrosion protection and low environmental impact.

The unhardened zone between the beginning and the end of the hardened region of the raceway is marked with an “S” on the inner or outer diameter of each bearing ring. On the gear ring, the hardness gap is marked on the axial surface. Wherever possible, the hardness gap “S” must be positioned outside the main load-carrying areas. If the main working area for the application is known, then the hardness gap of the ring loaded on the circum-ference must also be positioned outside the main load-carrying area.

The bearing must be completely screwed on for commissionings and test runs. Sufficient load / moment loan must be applied to avoid a slip-stick effect on the anti-friction bearing bodies.


Entanglement hazard due to exposed gear

  • Keep hands away from moving parts

The backlash is adjusted relative to the three gear teeth marked in green and should be 0.03 – 0.04 x module.After the final tightening of the bearing,the backlash should be rechecked over the entire circumference. A tip edge radius and a tip relief must be provided on the pinion.

Marine Propeller orientation device (POD)

Marine Propeller orientation device (POD)

LDB has a long history of providing a full range of slewing bearings for the azimuth positions of marine applications.

These highly tailored solutions cover outside diameters from 50 to 7 900 mm.

Our wide range of engineering expertise in bearings, seals, mechatronics, services and lubrication systems all contribute to the high quality of our marine solutions.

As proof, every bearing designed and produced for marine applications is subject to approval by certifying authorities.

Slewing Driver Application

Slewing reducer -Slewing driver can be applied to the host of the circular motion, such as the crane rotation platform and the rotation machinery, etc. The turbine and worm mechanisms are often used for two -axis intertwined, large transmission ratio, small transmission power, or intermittent work. This product can be widely used in the field of engineering machinery represented by high -altitude operating vehicles, car cranes, new energy fields represented by solar photovoltaic power generation, wind power generation, and other fields of automation, machine tool manufacturing, aerospace communications and other fields. Therefore, the product’s market potential is huge.

Slewing drive
Slewing reducer –Slewing driver Subjective list

Rotate machine with a dual snail turn drive drive

Driver driver with a car

Heavy tablet transport vehicle turning driver

High -altitude operating vehicle turning driver

Railway turning driver Driven driver

Slewing claws with rotation driver

Bridge detection vehicle rotation driver device

China Railway Liangji Slewing Driver Device

Solar turning driver

What are the sealing methods of the slewing bearing? Sealing function and method

We know that the slewing bearing has a very important role in some production, and in order to ensure these functions, we need to perform a lot of operations on the slewing bearing during the use of the slewing bearing. The sealing of the more common bearings, then why should the slewing bearing be used? to seal? What are the common sealing methods of slewing bearings?

The role of sealed slewing bearing

Slewing Bearings

1. Isolate foreign objects from outside

Protect the bearing to prevent external dust, dirt, metal particles, moisture, acid gas and other debris from invading the inside of the bearing. If the bearing is poorly sealed and external debris invades, the working condition of the bearing will be significantly deteriorated, and the service life of the bearing will be significantly reduced.

2. Prevent grease leakage

If the oil leaks, it will quickly destroy the normal lubrication of the bearing, causing the bearing to burn out due to heat. In addition, the poor sealing device not only causes waste of oil leakage, but also contaminates mechanical equipment and processed products. Therefore, to make the machine work properly, the bearing must have a good sealing device.

The way of sealing the slewing bearing

Slewing Bearings

Generally, the sealing methods of bearings include contact sealing and non-contact sealing, but these two sealing methods are suitable for different situations. Contact sealing is suitable for bearings operating in medium and low-speed working environments, while non-contact sealing Bearings that are suitable for high-speed and high-temperature working environments, as slewing bearings, generally operate at low speeds, but there are also high-temperature operations. The analysis shows that the methods of sealing slewing bearings are as follows:

1. Felt ring seal

A trapezoidal groove is opened on the bearing cover, and the fine felt on the rectangular surface is placed in the trapezoidal groove to contact the shaft, or the gland is pressed axially, so that the felt ring is compressed to generate radial pressure and hug the shaft, thereby achieve the purpose of sealing. The sealing structure is simple and the cost is low, but the sealing effect is poor, it cannot be adjusted, and the wear is serious.

2. The leather bowl is sealed

Place a sealing cup in the bearing cover (the cup is made of rubber and other materials) and press it directly on the shaft. In order to enhance the sealing effect, a ring-shaped coil spring is used to press the inner ring of the leather cup, so that the inner ring of the leather cup and the shaft have a tighter fit, and the sealing effect is better than that of the felt ring. /s of grease lubrication or lubricating oil lubrication.

3. Sealing ring seal

The sealing ring is usually made of leather, plastic or oil-resistant rubber, and can be made into different cross-sectional forms as required. The 0-shaped sealing ring has a circular section and is pressed on the shaft by its own elastic force. It has a simple structure and is easy to assemble and disassemble. Also commonly used are J-shaped and U-shaped profile seals, which all have a lip-shaped structure. The direction of the sealing lip is towards the sealing part, which is similar to the direction of the flange in the cup seal. When the temperature is high and the rotational speed is high, it is recommended that the sealing lip also be installed away from the bearing. The sealing effect of the sealing ring is better than that of the felt ring, and it can be used for the sealing of grease and oil.


4. Skeleton seal

The skeleton seal we often say is the improvement of the leather cup seal. In order to improve the overall strength of the leather cup seal, a metal lining with an L-shaped cross-section and an overall annular shape is installed in the oil-resistant rubber, so that the leather cup seal is not easily deformed and improves the use of This kind of seal is easy to install and has good performance. It is generally suitable for occasions where the peripheral speed of the journal is 7m/s.

5. Sealing ring seal

This is an annular seal with a gap, which is placed in the ring groove of the sleeve, the sleeve rotates with the shaft, and the seal ring is pressed against the static part by the elasticity of the gap after being compressed. On the inner hole wall, it can play a sealing role, and this kind of sealing is more complicated.

6. Labyrinth seal

The basic principle of this kind of seal is to form a section of flow channel with great flow resistance at the seal. Structurally, a small tortuous gap is formed between the stationary part and the rotating part, forming a “labyrinth”. If the “labyrinth” is radial, the axial dimension is compact, but the radial dimension is larger. If the “labyrinth” is axial, the radial dimension is compact, but the bearing cover should be divided, and the axial clearance should be larger, so as not to be stuck due to thermal deformation of the shaft. Labyrinth seals are quite reliable for both lubricating oil and bone grease, and the higher the speed, the better the effect.

The above is the summary of the sealing methods of the slewing bearing, and the whole content of the sealing function and method. We have learned that the slewing bearing has the functions of isolating foreign objects and preventing grease leakage. The common methods are felt ring sealing, leather cup Seal, seal ring seal, skeleton seal, seal ring seal, labyrinth seal, etc., you can choose according to the specific situation of your bearing

What are the application fields of slewing drive

The slewing drive can be applied to the main engine that does circular motion, such as crane turntable, rotating machinery, and other machines that perform circular work.

Slewing drive can be widely used in the field of construction machinery represented by aerial work vehicles and truck cranes, as well as in the field of new energy represented by solar photovoltaic power generation and wind power generation, as well as other fields of automation, machine tool manufacturing, aerospace communications, etc. It can be said that this product The market potential is huge.

1. The field of beam transport vehicles

The core components of the traditional beam-carrying slewing assembly mostly use traditional slewing bearing products. Since the slewing bearing does not have an outer casing, the corrosion resistance is not ideal. For the steering system that relies on hydraulic cylinders to push the tires, the The range of rotation angles is also greatly limited.

VE Series Slewing Drive

2. Field of aerial work vehicles

Aerial work vehicles are an important application area of ​​slewing drive. Usually, aerial work vehicles require the main engine to have a high safety factor. The high safety of slewing drive (self-locking of worm gears) is the choice of the majority of users as accessories for aerial work platforms. An important factor; on the other hand, the worm gear transmission has a larger transmission speed ratio, which improves the safety factor of the main engine and also omits a set of worm gear reducers for the main engine, thereby reducing the manufacturing cost of the main engine.

3. Photovoltaic power generation field

Photovoltaic power generation is an important application field of rotary drive. The use of solar photovoltaic modules with rotary drive as a rotating component can accurately adjust the rotation angle and elevation angle of the host according to the different positions of the sun during the day. the receiving angle.

SE Series Slewing Drive

4. Wind power generation

Similar to the photovoltaic discovery, the slewing drive can be applied to the yaw part of the wind turbine to realize the horizontal 360 rotation of the mechanism, so as to better adjust the receiving angle.

5. The field of construction machinery claws

Auxiliary equipment for construction machinery is a brand-new application field of slewing drive.

The above is all about the application field of slewing drive. If you have any questions during use, please feel free to communicate with us in depth.

Will the slewing drive raceway be damaged? Causes of raceway damage and preventive measures

The main structure of the slewing reducer is a structure in which the slewing bearing is used as a transmission follower and a mechanism attachment, and the slewing bearing itself is used to cooperate with the driving power source and the main transmission parts to complete the rotation, deceleration and driving. The slewing bearing is still one of the more critical components, so will the raceway of the slewing drive be damaged? Below, Xiaobian will give you a detailed introduction.

Will the raceway of the slewing drive be damaged?

Will be damaged. As an important component used by many construction machinery, the slewing reducer will inevitably have problems such as wear and fatigue damage during daily use. Because of its slewing structure, it is inevitable that the raceway will be damaged during work. . In addition to the insufficient rigidity of the raw materials in the manufacturing process, the reasons for the damage to the raceway may include unreasonable structural design and insufficient manufacturing accuracy of the reducer. Let’s take a look at it in detail:

VE Series Slewing Drive

Causes of damage to the slewing drive raceway

1. Heat treatment process

The processing quality of the rotary reducer itself is related to the manufacturing accuracy, heat treatment state, and axial clearance. What we usually ignore is the influence of the heat treatment state. In addition to the external force, the most important thing for the damage of the raceway is the depression and cracks on the surface of the raceway during its production. This is related to the hardness of the raceway surface and the hardness of the hardened layer and the core, and these factors are determined in the heat treatment process. For this reason, the depth of the hardened layer on the raceway surface is insufficient and the hardness of the core is low. A more critical factor in its raceway damage.

2. Structural rigidity of turntable

The key component that transmits various loads between the turntable and the chassis when driven by gears. The rigidity of the turntable itself is not large. It mainly depends on the rigidity of the chassis and the structure of the turntable that supports it. When the structural rigidity of the turntable is not enough, the turntable under large eccentric loads The deformation of the bottom plate connected to the slewing mechanism is more serious, which in turn causes the equipment load to concentrate on a small part of the rollers, thereby increasing the pressure on a single roller, resulting in the contacting raceway also bearing a large contact stress, which It is also one of the reasons for the damage to the raceway.

SE Series Slewing Drive

Preventive measures for rotary drive raceway

1. Pay attention to the rated load: the rotary drive should not be overloaded;

2. Correct model selection: Select the appropriate slewing drive according to your needs. When purchasing the slewing drive, you must strictly calculate the various parameters of the slewing drive, and select the turntable bearing that suits the actual needs. road damage;

3. Pay attention to maintenance: maintain regular maintenance, and regularly add lubricating oil to the rotary drive. Only through reasonable maintenance and maintenance can we ensure that the slewing drive raceway is not easily damaged and prolong the service life of the slewing drive.
The above is the answer to the question about whether the raceway of the slewing drive will be damaged. It includes the reasons for the damage of the raceway and preventive measures. In fact, whether it is the drive device or the bearing itself, as mechanical parts, there is a certain fatigue limit, which should be based on Use the guide reasonably and maintain it properly, so as to better play the role and value of the equipment.

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

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

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;


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.