How does a four-point contact ball slewing ring work

What is four-point contact ball slewing ring

The four-point contact ball slewing ring is a kind of mechanical transmission parts with exquisite structure and excellent performance, and its core structure includes the inner ring, the outer ring, the steel ball and the cage, and the arc raceway of the inner and outer rings forms a unique four-point contact mode with the steel ball. This innovative design gives it strong mechanical properties, efficient handling of axial, radial and overturning forces at the same time, excellent load-bearing capacity and good stiffness characteristics thanks to a uniform distribution of contact stresses. When working, it relies on the rolling of the steel ball in the raceway to realize the flexible rotation between the inner and outer rings to ensure the stability and accuracy of the equipment operation. In practical applications, it can be seen from heavy-duty cranes and excavators, to wind turbines in the field of clean energy, to rotary workbenches on automated production lines, and is a key component of many equipment that requires rotary movement and has high requirements for load bearing and accuracy.

Features of four-point contact ball slewing rings

High bearing capacity: The unique four-point contact structure makes the steel ball have four contact points with the inner and outer ring raceways, which can withstand axial force, radial force and overturning moment at the same time, and can adapt to complex stress conditions with high bearing capacity.

Good rotation accuracy: the steel ball rolls in the raceway, the movement is stable, and the uniformity of the four-point contact helps to ensure the accuracy of the rotary movement, which can meet the application scenarios with high requirements for rotary positioning accuracy.

Compact structure: Compared with some other types of slewing rings, under the same bearing capacity, the structure of four-point contact ball slewing rings is relatively compact, and the space occupied is small, which is conducive to the miniaturization design of equipment.

Easy installation: its structure is relatively simple, the installation process is relatively convenient, and there are usually mounting holes on the inner and outer rings, which are convenient for connection and fixation with other parts of the equipment, which can effectively improve the installation efficiency.

Low maintenance cost: rolling friction is adopted, the friction coefficient is small, the wear is relatively small, and it is generally equipped with a good sealing and lubrication system, which can effectively reduce the intrusion of external impurities and the wear of components, thereby reducing maintenance costs and prolonging service life.

Strong adaptability: According to different work requirements, by changing the material, surface treatment process and structural parameters, etc., to meet the needs of various harsh working environments and special working conditions, such as high temperature, low temperature, high humidity, corrosive environment, etc.

How does a four-point contact ball slewing ring work

The four-point contact ball slewing ring is mainly composed of an inner ring, an outer ring, a rolling element (steel ball), a cage and a sealing device. Here's how it works:

Bearing principle: There are arc-shaped raceways on the inner and outer rings of the four-point contact ball slewing ring, and the steel ball is located between the inner and outer ring raceways. When there is axial load, the steel ball is in contact with the inner and outer ring raceways at four points, which can effectively bear the axial force, and through this four-point contact mode, the load is evenly distributed on each steel ball, so as to improve the bearing capacity of the slewing bearing. At the same time, it can also withstand a certain radial load and overturning moment, because the design of the raceway makes the steel ball maintain a good contact state when bearing the radial force and overturning moment, ensuring the stability of the slewing bearing.

Slewing principle: The steel ball between the inner and outer rings is guided by the cage and can roll freely in the raceway. When the inner or outer ring is subjected to an external force, the steel ball rolls along the raceway, thus achieving relative rotation between the inner and outer rings. Due to the small rolling friction coefficient between the steel ball and the raceway, the slewing ring can rotate with a low frictional torque, which ensures the slewing accuracy and flexibility of the equipment.

Sealing principle: The sealing device is usually installed between the inner and outer rings of the slewing ring, which is used to prevent dust, moisture, oil and other impurities from entering the slewing ring, and also to prevent the leakage of lubricants inside. Common sealing forms include lip seals, labyrinth seals, etc. The lip seal is tightly attached to the inner and outer ring surfaces of the slewing ring through the sealing lip to form a sealing barrier; Labyrinth sealing is the use of labyrinthine channel structure to increase the resistance of impurities to enter, so as to achieve the effect of sealing. Good sealing performance can ensure a good lubrication and clean environment inside the slewing ring, prolonging its service life

Application of four-point contact ball slewing rings

Four-point contact ball slewing rings are widely used in many fields due to their unique structural and performance characteristics, and the following are some common application scenarios:

Construction machinery field

Cranes: including tower cranes, truck cranes, etc. The four-point contact ball slewing ring is used to connect the crane boom and the slewing platform, so that the crane arm can rotate flexibly, realize the lifting of heavy objects in different directions, and bear the axial force, radial force and overturning moment generated by the crane arm and the heavy object at the same time.

Excavator: Installed between the upper structure of the excavator and the lower chassis, the upper working device (such as boom, stick, bucket, etc.) realizes 360° rotation relative to the lower chassis, so that the excavator can flexibly adjust the working angle during excavation operations and adapt to the excavation needs of different positions.

Aerial work platform: It can make the operators and equipment on the platform rotate within a certain range, facilitate high-altitude installation, maintenance, cleaning and other operations, provide a broader working range for operators, and ensure the stability and safety of the platform in the rotation process.

Wind power generation: Between the nacelle and the tower used for wind turbines, the nacelle can rotate according to the change in wind direction, ensuring that the wind wheel is always aligned with the wind direction to maximize the capture of wind energy. The four-point contact ball slewing ring needs to bear the weight of the nacelle, the thrust of the wind turbine and various complex wind loads to ensure the stable operation of the wind turbine.

In the field of port machinery: such as port portal cranes, shore container cranes, etc., four-point contact ball slewing ring is one of its important components. It supports the rotating part of the crane, including the boom, driver's cab, etc., so that the crane can carry out efficient cargo loading and unloading operations at the port terminal, while adapting to the complex working environment and large load changes in the port.

In the field of industrial automation: it is also used in the rotary workbench of the automated production line, industrial robots and other equipment. The rotary worktable uses a four-point contact ball slewing ring to achieve high-precision rotary positioning, which meets the process requirements of material handling, processing, and assembly in the production process; The use of slewing bearings in the joints of industrial robots helps to improve the robot's motion flexibility and positioning accuracy, and realize complex movements and operations.

In the field of military equipment: in some military equipment, such as the rotating base of the radar antenna, the rotary platform of the missile launcher, etc., the four-point contact ball slewing bearing plays an important role. It can ensure that the radar antenna can quickly and accurately turn in different directions for target search and tracking, as well as the stable rotation and positioning of the missile launcher during launch.

Four-point contact ball slewing ring supplier

As a well-known supplier of slewing bearings with 30 years’ experience, LTZC bearings is committed to providing slewing bearings with high quality and low price. The specific price needs to be comprehensively evaluated according to the size, load, material and accuracy requirements of the bearings. Please contact us if necessary.