How to choose the right 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 to choose the right four-point contact ball slewing ring?

There are several factors to consider when choosing the right four-point contact ball slewing ring, but here are some key takeaways:

Load capacity

Axial load: It is determined according to the axial force borne by the equipment in actual operation. For example, in cranes, large axial tension will occur when lifting heavy objects, and slewing bearings are required to be able to bear the corresponding axial loads to ensure the stable operation of the crane.

Radial load: Considering the radial force that the equipment may be subjected to during operation, such as the excavator in the excavation operation, the swing of the stick will produce radial force on the slewing ring, and the radial load bearing capacity of the selected slewing ring should be able to meet the requirements of this working condition.

Overturning torque: For some equipment that will produce a large overturning torque, such as tower cranes, when selecting a slewing ring, it is necessary to ensure that it has sufficient anti-overturning capacity to prevent the equipment from tipping accidents during the working process.

RPM requirements

Different equipment has different requirements for the speed of the slewing ring. For example, a rotating table in an industrial automation production line may require higher rotational speeds for fast material handling and processing, while the yaw system of a wind turbine has a relatively low rotational speed. Therefore, it is necessary to select the appropriate slewing ring according to the actual speed demand of the equipment to ensure that it can operate stably at the corresponding speed and avoid problems such as overheating and aggravated wear.

Accuracy class

Rotation accuracy: For some equipment with high requirements for rotation accuracy, such as CT machines in medical devices, a slewing ring is required to achieve high-precision rotary positioning to ensure the accuracy of imaging. In this case, a slewing ring with a higher accuracy level should be selected, such as P4, P5, etc.

Installation accuracy: Considering the accuracy requirements of equipment installation, the installation accuracy of slewing rings will affect the overall performance of the equipment. For example, in the robot joint, the slewing ring with high installation accuracy can ensure the accuracy and repeatability of the robot's movements.

Working environment

Temperature: If the equipment works in a high-temperature environment, such as near the heating furnace in the metallurgical industry, it is necessary to choose a high-temperature resistant slewing ring, and its material and lubrication method should be able to adapt to high-temperature working conditions to prevent material deformation, lubrication failure and other problems. In low-temperature environments, such as polar operation equipment, slewing rings need to have good low-temperature performance to ensure that they can start and operate normally at low temperatures.

Humidity: In humid working environments, such as ports, mines, etc., slewing rings are susceptible to corrosion, and slewing rings with good anti-rust ability should be selected, such as slewing rings made of stainless steel materials or with special surface treatment.

Dust and impurities: In dusty environments, such as mining, building construction and other places, dust and impurities are easy to enter the inside of the slewing ring and aggravate the wear, so it is necessary to choose a slewing ring with good sealing performance to prevent the instruation of dust and impurities.

Installation:

Bolted joint: Bolted connection is a common installation method and is suitable for most equipment. When selecting slewing rings, it is necessary to select matching slewing rings according to the mounting hole size and bolt specifications of the equipment to ensure that the installation is firm and reliable.

Welded connection: For some equipment that requires high-strength connection, such as the slewing platform of a large crane, a welded connection may be used. At this time, the structure and material of the slewing ring should be able to adapt to the requirements of the welding process to ensure the welding quality and connection strength.

Brand and quality

Market reputation: Choose brands with good market reputation, which usually have certain advantages in product quality, performance and after-sales service. You can find out how trustworthy your brand is by consulting relevant materials, consulting industry experts, or referring to the experiences of other users.

Quality certification: Check whether the slewing ring has passed the relevant quality certifications, such as ISO 9001 quality management system certification, ISO 14001 environmental management system certification, etc., and whether it meets industry standards and specifications, such as JB/T 2300-2011 "Slewing Ring", etc., to ensure that the product quality and performance meet the requirements.

Cost factor

Procurement cost: The price of slewing rings of different brands, specifications and quality grades varies greatly, and the procurement cost should be considered comprehensively according to the budget and use requirements of the equipment when choosing. On the premise of meeting the performance requirements of the equipment, try to choose cost-effective products.

Maintenance cost: Consider the maintenance cost of the slewing ring, including the replacement of grease, the replacement of seals, and the ease of maintenance. Some slewing rings with good quality and high reliability may be more economical in the long run, although the purchase cost is higher, the maintenance cost is lower.

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.