How do I choose the right seal for four-point contact ball slewing ring?

What is four-point contact ball slewing ring

The four-point contact ball slewing ring is composed of the inner ring, the outer ring, the steel ball and the retaining frame, the inner and outer rings are provided with arc-shaped raceways, and the steel ball and the raceway form a four-point contact slewing part, this unique structure makes it able to bear axial force, radial force and overturning moment at the same time, the contact stress is evenly distributed, the bearing capacity is high and the rigidity is good; When working, the steel ball is rolled in the raceway to achieve relative rotation of the inner and outer rings, which can ensure the smooth and accurate movement, and is widely used in cranes, excavators, wind turbines, automatic production line rotary workbenches and other equipment that needs to rotate and has requirements for 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 do I choose the right seal for four-point contact ball slewing ring?

To choose a sealing device suitable for four-point contact ball slewing rings, you need to consider the working environment, operating conditions, sealing performance requirements and other factors of the slewing rings, and the following are the specific selection points:

Working environment

Dust and impurities: If the slewing ring works in a dusty environment, such as mines, construction sites, etc., it is necessary to choose a sealing device with good dustproof performance, such as a double lip seal or a labyrinth seal. The double lip seal has two sealing lips, which can effectively block the entry of dust; Labyrinth seals through a complex channel structure that increases the resistance of dust ingress.

Humidity and moisture: In humid or easily exposed to water, such as ports, water conservancy projects, etc., the sealing device should have good waterproof performance. Seal construction with rubber seals or seals with a water-repellent coating are available to prevent moisture from penetrating the inside of the slewing ring and causing corrosion.

Temperature: The high-temperature environment will cause the sealing material to age and deform, and reduce the sealing performance, so in high-temperature occasions, such as near the high-temperature furnace of steel mills and cement plants, high-temperature sealing materials should be selected, such as fluoroelastomer, silicone rubber, etc. The low-temperature environment requires the sealing material to have good flexibility to avoid losing the sealing effect due to low-temperature hardening, and cold-resistant rubber and other materials can be selected.

Operating conditions

Rotation speed: When the rotation speed of the slewing ring is high, the sealing device will be subjected to greater centrifugal force and friction, and it is necessary to choose sealing materials with small friction coefficient and good wear resistance, and the sealing structure should be able to adapt to high-speed rotation. For example, seals made of self-lubricating materials such as PTFE maintain good sealing performance at high speeds.

Load: When the slewing ring is subjected to a large load, the sealing device may be crushed and deformed, which requires the seal to have sufficient strength and elasticity to maintain the sealing performance under the load. For example, the metal skeleton rubber seal can provide a certain supporting strength, and the rubber part has good elasticity, which is suitable for slewing rings that bear large loads.

Sealing performance requirements

Sealing level: According to the strictness of the sealing performance of the slewing ring, select the device of the corresponding sealing level. For occasions with high requirements, such as aerospace, precision machine tools and other fields, it is necessary to use sealing devices with high sealing levels, such as mechanical seals, which have good sealing effects, but complex structures and high costs. For general industrial applications, a common lip seal or labyrinth seal is usually sufficient.

Leakage: If there is a strict limit on the amount of leakage, a device with better sealing performance should be selected. For example, the use of a multi-stage seal structure and the combination of a lip seal and a labyrinth seal can effectively reduce the amount of leakage. At the same time, it is necessary to select the appropriate sealing material and structure according to the allowable leakage amount to ensure that the sealing device meets the leakage requirements in long-term operation.

Installation & Maintenance

Installation space: The size and structure of the sealing device should match the installation space of the slewing ring. If installation space is limited, a compact, compact sealing structure, such as a built-in seal, is required. For slewing rings with large space, external sealing devices with more complex structures but better sealing effects can be considered.

Ease of Maintenance: Choose seals that are easy to install, dismantle and replace for regular maintenance and overhaul while the slewing ring is in use. For example, some seals with quick-release construction can be quickly installed and removed without special tools, improving maintenance efficiency.

In addition, when selecting a sealing device, you can also refer to the recommendations and experience of the slewing ring manufacturer, as well as the sealing application cases of other equipment under similar working conditions, and comprehensively consider various factors to select the most suitable sealing device.

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.