What is the industry standard for the machining accuracy of raceways in the inner and outer rings of double-row ball slewing rings?

What is double ball slewing ring

As the key component to realize the rotary motion of the equipment, the double row ball slewing ring is usually composed of the inner ring, the outer ring, two rows of steel balls and the holding frame, and the steel balls placed in the raceway of the inner and outer rings are evenly separated by the cage, and this structure enables it to bear large axial force, radial force and overturning moment at the same time; Its working principle is based on rolling friction, the inner ring and the outer ring rotate relative to each other when rotating, and the steel ball rolls in the raceway, through the reasonable design of the raceway curvature and the diameter of the steel ball, the load can be evenly distributed to improve the bearing capacity and service life. The bearing has significant performance advantages, not only because the double-row ball structure has a high bearing capacity, suitable for heavy-duty conditions, but also because of the high-precision raceway and steel ball processing to meet the high-precision operation needs of the equipment, and high-quality materials and reasonable design make it have a long life, reduce maintenance and replacement costs, and at the same time the structure is relatively simple, easy to install and disassemble

Features of a double row ball slewing ring

Double-row ball slewing ring is a mechanical component used to withstand large axial forces, radial forces and overturning moments, and has the following characteristics:

Strong bearing capacity: The double row ball slewing ring has two rows of steel balls, which can withstand axial force, radial force and overturning moment at the same time. Compared with the single-row ball slewing ring, its bearing capacity is greatly improved, which can meet the force requirements of large machinery and equipment under complex working conditions, such as large cranes, shield machines and other equipment, which can withstand the huge load generated by lifting heavy objects and various forces during equipment operation.

High Rotation Accuracy: Through precise machining technology and assembly technology, double row ball slewing rings can ensure high rotation accuracy. The matching accuracy of the raceway and the steel ball is high, which can make the equipment stable during rotation and reduce vibration and swing, which is very important for some equipment that requires high precision, such as radar antennas and astronomical telescopes, to ensure that it accurately points to the target and improves the working performance.

Good rigidity: The structural design of the double row ball makes it have good rigidity. When bearing load, it can effectively resist deformation and maintain the stability of the structure. This helps to improve the overall strength and reliability of the equipment, and prolong the service life of the equipment, especially in some heavy-duty and high-impact working environments, such as mining machinery, port machinery, etc., which can better adapt to harsh working conditions.

Stable operation: the steel ball rolls in the raceway, the friction resistance is small, and the distribution of the double row ball makes the load evenly distributed, so as to ensure the stability of the slewing ring during operation. The equipment runs smoothly when rotating, reducing noise and vibration, improving the quality of the operator's working environment, while also reducing wear and impact on other parts of the equipment.

Easy installation: Double row ball slewing rings are usually designed with standardized mounting interfaces and dimensions for easy connection and installation with other parts of the equipment. Its structure is relatively compact, occupies a small space, and can achieve a large bearing capacity and rotation function in a limited space, which provides convenience for the design and manufacture of equipment.

Low maintenance cost: Due to its simple structure and reliable operation, the maintenance of double row ball slewing rings is relatively easy. It only needs to regularly check the lubrication, sealing performance and wear of components, lubricate and replace worn parts in time, which reduces the maintenance cost and downtime of the equipment and improves the efficiency of the equipment.

What is the industry standard for the machining accuracy of raceways in the inner and outer rings of double-row ball slewing rings?

The industry standard related to the machining accuracy of the raceway of the inner and outer rings of double row ball slewing rings is mainly based on JB/T 2300 - 2011 "Slewing Rings". Here are some of the main accuracy requirements:

Dimensional accuracy

Diameter tolerance: The diameter and dimensional tolerances of the inner and outer ring raceways are usually determined according to the specifications and accuracy class of the slewing ring, and are generally required to be controlled within a small range, for example, for the slewing ring of the medium accuracy class, the raceway diameter tolerance may be between ±0.05mm - ±0.1mm.

Width tolerance: The raceway width tolerance is also strictly required to ensure the normal rolling and load-bearing capacity of the balls in the raceway, usually the width tolerance is controlled around ±0.1mm - ±0.2mm.

Shape accuracy

Roundness: The roundness error of the raceway should not exceed a certain value, the roundness of the raceway of the general high-precision slewing ring is required to be between 0.002mm - 0.005mm, and the roundness of the medium precision is between 0.005mm - 0.01mm.

Cylindricity: Cylindricity is also an important indicator to measure the shape accuracy of the raceway, for the raceway of the double row ball slewing bearing, the cylindricity error is usually required to be controlled within 0.005mm - 0.01mm, so as to ensure the good contact between the ball and the raceway and uniform force.

Positional accuracy

Concentricity: The coaxiality of the inner and outer ring raceways is required to be high, and the coaxiality error of the general high-precision slewing ring should be controlled within 0.01mm - 0.02mm to ensure the accuracy of the rotary center and the rotation accuracy.

Parallelism: The parallelism error of the raceway is also strictly limited, usually between 0.01mm - 0.03mm, in order to ensure the smoothness and uniformity of the force when the ball rolls in the raceway.

Surface roughness: The surface roughness of the raceway is generally required to reach Ra0.4 - Ra0.8μm to reduce the friction and wear between the ball and the raceway, and improve the efficiency and service life of the slewing ring.

In addition, there may be stricter machining accuracy standards in some specific application areas or when customers have special requirements. For example, in aerospace, precision machine tools and other fields, the machining accuracy requirements for slewing ring raceways may be higher, the dimensional tolerance may be controlled within ±0.01mm, and the shape accuracy and position accuracy will be improved accordingly.

Supplier of double row ball slewing rings

LZTC Double Row Ball Slewing Rings provides a series of services such as R&D, design, production and sales of double row ball slewing ring products. If you are looking for a double row ball slewing ring supplier, please contact us for the latest quote.