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The slewing bearing is a large bearing with a special structure that can bear comprehensive loads such as large axial loads, radial loads, and overturning moments at the same time, and integrates multiple functions such as support, rotation, transmission, and fixation.

Slewing bearings are widely used. Construction machinery is the first and most widely used place for slewing bearings, such as earthmoving machinery, excavators, dismantling machines, stackers and reclaimers, graders, road rollers, dynamic compaction machines, rock drilling machinery, roadheaders, etc.Before the slewing bearing is installed, the installation surface of the main engine should be inspected first. It is required that the support should have sufficient strength, the connection surface should be machined, and the surface should be smooth without sundries and burrs. For those that cannot be machined to achieve the required flatness, special plastics with high injection strength can be used as fillers to ensure the accuracy of the installation plane and to reduce vibration.

In addition to various construction machinery, the application range of slewing bearings has gradually expanded, and equipment platforms such as port equipment, metallurgical equipment, and drilling platforms have begun to use slewing bearings to replace the original bearings on a large scale.Port equipment: port cranes, reach stackers;New energy equipment: wind power generation equipment, solar power generation equipment;Metallurgical equipment: metallurgical cranes, ladle turrets, steel grabbers, mud cannons, oxygen blowing devices;Amusement equipment: Ferris wheel, etc.; Airport equipment: airport refueling machine; Military equipment: radar, tanks, etc.; Robots: palletizing robots, welding robots, manipulators; Medical equipment: Gamma Knife; Environmental protection equipment: mud scraper;

Turntable slewing bearing application:

1. Trailer: This type of bearing is used in many occasions, the most important of which are used in the transportation industry, agricultural trailers, irrigation systems and airport luggage racks. In vehicle applications, the bearings transmit axial loads, radial loads and torques. In other applications, they mostly transmit axial loads. LZK specializes in the manufacture of turntable slewing bearings for trailers.
2. Wind power: Wind turbine bearings usually include yaw bearings, pitch bearings, transmission system bearings (main shaft and gearbox bearings). LZK provides customers with yaw bearings and pitch bearings. The yaw bearing is installed at the connection between the tower and the cockpit, and the pitch bearing is installed at the connection between the root of each blade and the hub. Each wind turbine uses one set of yaw bearings and three sets of pitch bearings.
3. Solar energy: Rotating solar panels are a great solution for increasing energy. Thanks to the very compact design of the LZK bearings, the largest solar farm in Europe is supplied.
4. Medical equipment: The high-precision, low-noise, long-life, high-reliability series of medical equipment spindle turntable slewing bearings developed by LZK Bearing have been widely used in large medical equipment such as gamma knife, CT machine, and nuclear magnetic resonance machine.
5. Robots: industrial robots and other equipment. LZK turntable bearings are installed on the joints of the robot, and this structure can achieve incredibly high-precision rotary motion.

With the prolongation of the running time of wind turbines, due to the harsh environment of wind farms, gearbox failures occur more and more frequently, such as oil leakage, tooth surface pitting, peeling, broken teeth, abnormal wear, bearing running circles, raceway pitting , Peeling and other phenomena.

There are many factors leading to the above defects, including manufacturing factors: gearbox structure design, load calculation, bearing selection, material selection, manufacturing and processing, test run and cleaning before leaving the factory, etc.; operating factors: control strategy, monitoring measures, maintenance methods; environment Factors: climate, changing wind conditions; control factors: if any link is not properly controlled, it will lead to hidden dangers, which will expand from small defects to large defects, causing irreversible damage to mechanical parts.

Therefore, from the factory to the phase-out and scrapping of wind turbine gearboxes, we must use the concept of full-life cycle management to reduce the damage rate and removal rate of the gearbox and shorten the recovery time through careful maintenance and scientific management, so as to achieve long-life and healthy operation of the gearbox. Improve unit utilization.

There are many reasons for the gear box to be damaged and removed from the shelf. Through investigation and data statistics, the defects are mainly manifested as: broken teeth of gears, pitting, wear and peeling of tooth surfaces, broken inner ring gears, damaged and stuck planetary gears, worn bearings, running of inner and outer rings. circle etc. The direct cause of these defects is mainly due to poor contact of the teeth, eccentric loading, excessive local stress, causing micro-cracks and gradually expanding, resulting in burns, pitting, and peeling of the tooth surface, resulting in local fracture of the tooth. The indirect causes of these phenomena may be related to factors such as design and manufacturing, materials and heat treatment, operation and maintenance, control strategies, and the environment. The specific situation of each gearbox will be different, but generally speaking, the initial manufacturing defect is a potential cause. During use, complex loads, improper maintenance, and failure to track and deal with it in time will accelerate the expansion of defects.

In the process of equipment design, installation and use, the selection of bearing grease temperature is very important. For motors, the commonly used lubricating medium is grease.

Generally, grease suppliers will mark some data on the technical parameters of grease, including dropping point, operating temperature range, etc.

On the other hand, there are many temperature calculations in different technical data.

Occasionally, the results of various calculations, as well as the temperature limits of other parts of the bearing, are not quite the same as those specified for the grease. Numerous concepts and calculations lead engineers into a puzzle when choosing.

Next, we will sort out these concepts to help engineers have a clearer idea when selecting grease temperature.

Grease temperature selection
Grease is usually selected to provide adequate lubrication to the bearing under a given operating condition. At this time, it is necessary to check the “given operating conditions” and “meet the lubrication performance”. This is the usual lubrication selection check calculation.

It has been said in the past (you can also refer to “Motor Bearing Application Technology”, “Motor Bearing Fault Diagnosis and Analysis”, “Gearbox Bearing Application Technology”, and other articles in this public number), the selection and check calculation of lubricating grease is essentially Check Kappa coefficient. When the Kappa coefficient is between 1 and 4, it means that the selected lubrication meets the lubrication requirements.

During the calculation, it can be noticed that there are many temperature effects. For example, the viscosity change curve is actually the change curve of viscosity against temperature.

The essence of this check calculation is to check whether the selected grease can meet the Kappa coefficient falling between 1-4 at the current temperature. If the answer is yes, then the choice is appropriate, otherwise it needs to be adjusted.