Different types of slewing ring

Slewing bearing is a kind of large bearing which can bear comprehensive load, and can bear large axial, radial load and overturning moment at the same time. Slewing ring usually has installation holes, internal or external gears, lubricating oil holes and sealing devices, so it can make the main engine design compact, easy to guide and maintain. It has four series: teeth-type, outer-type and inner-type four-point contact ball bearings, double-row angular contact ball bearings, cross-cylindrical roller bearings, cross-tapered roller bearings and three-row cylindrical roller composite bearings. Slewing rings are widely used in marine equipment, construction machinery, light industry machinery, metallurgical machinery, medical machinery, industrial machinery and other industries.

Content list of this article：

• Definition

• Types

• The correct choice

• Sum up

What is slewing ring bearing？ 

The slewing ring is also called a rotary support and a rotary support. The slewing bearing is a new type of mechanical component. It has inner and outer rings, rolling elements, etc. It is a large bearing capable of withstanding the combined load, and can withstand large axial, radial loads and overturning moments at the same time. It is widely used in the real industry. It is called “the joint of the machine”, which is a mechanical device that needs to perform relative rotary motion between two objects, and also needs to bear axial force, radial force and tilting moment. Important transmission components required. With the rapid development of the machinery industry, it has been widely used in marine equipment, engineering machinery, light industrial machinery, metallurgical machinery, medical machinery, industrial machinery and other industries.

Types of slewing ring

According to the position of the tooth, it can be divided into three types: toothless type, external tooth type and internal tooth type.

According to the internal structure, it can be divided into four types of contact ball bearings, double row angular contact ball bearings, crossed cylindrical roller bearings, crossed tapered roller bearings and three rows of cylindrical roller combined bearings. Among them, the four-point contact ball bearing has a high static load capacity; the crossed cylindrical roller bearing has a high dynamic load capacity; the cross-tapered roller bearing can achieve a large bearing rigidity and high rotation accuracy by pre-interference.

1. Single volleyball slewing ring

A row of steel balls is used as the rolling element, and there is a single isolation block between the steel balls. The inner and outer rings are monolithic, and the steel balls are loaded by blocking the holes. The steel ball is in contact with the raceway at four points and can withstand axial forces, radial forces and tipping moments. It is the first choice for small and medium size with a diameter of less than 1800mm.

2．Double row four point contact ball slewing ring

It structure is similar to the single volleyball type slewing ring, except that it uses two rows of steel balls as the rolling elements, and the two rows of steel balls have the same size, and a single isolation block is arranged between the steel balls. The inner and outer rings are monolithic, and the steel balls are loaded by blocking the holes. It requires a preferred product for heavy-duty, radial-constrained mainframes.

3．Three rows of column slewing bearings

It is with high load carrying capacity, which is mainly used in heavy load applications. It consists of three ferrules. The upper and lower rows of rollers are horizontally distributed to withstand axial forces and tipping moments in both directions. The radial force is absorbed by the vertically arranged third row of rollers. It is the choice of large with diameters greater than 1800 mm.

4．Cross roller type slewing ring

It is similar to the single volleyball slewing bearing. There is only one row of rolling elements, the rolling elements are cylindrical rollers, the axes of adjacent rollers are arranged at 90°, and the inner and outer rings each have two raceways. The raceway section is linear. Half of the rollers are subjected to a downward axial force and half are subjected to an upward axial force.

5．Double row reducer ball slewing ring

It consists of upper and lower double-row steel balls, inner and outer rings, isolation blocks and lubrication and sealing devices. However, the three-row slewing type of the three-row slewing type has a complicated structure.

How to select useful slewing bearing？

1. Accuracy

Cross-roller slewing bearings are often used when precision positioning is a critical operating parameter.

2.  Load

The size of the load is one of the factors that determine the size of the bearing. Typically, four-point contact ball slewing bearings can withstand heavy loads and shock loads. They are suitable for applications where the size and direction of the load will change.

3.  Allowable operating temperature

In most cases, the allowable operating temperature of it is primarily dependent on the gasket and sealing material used for lubrication. The permissible operating temperature range is -25 to + 70 °C.

3.  Vibration

For applications involving vibration, preloaded four-point contact ball slewing bearings and crossed cylindrical roller slewing bearings are suitable.

5.  Running speed

The four-point contact ball slewing bearing produces less friction than the crossed cylindrical roller slewing ring. It also has a higher rotational speed.

6.  Seal

Sealing is critical to the performance of it. Qualified seals used in it provide good protection against moisture and contamination and ensure the function of grease. If the bearing is working under extreme conditions, such as exposure to water, vacuum, corrosive contaminants or radiation, you need to contact the company.

Sum up

When selecting the slewing bearing, the appropriate size can be rotated according to the specific working conditions, the axial force, the radial force and the overturning moment. The type of slewing bearing can be selected according to the specific use accuracy requirements. It can also be selected according to the specific use environment, temperature and other special requirements.