Rotary bearing, also known as slewing bearing, is a large bearing which can bear large axial load, radial load and overturning moment at the same time. Turntable bearings are generally equipped with mounting hole, inner gear or outer gear, lubricating oil hole and sealing device, thus can make the main structure design compact, reliable, easy to maintain.
According to the type of teeth, the slewing bearing is divided into toothless type, external type and internal type.
According to the structure, it is divided into four point contact ball bearing, double row Angle contact ball bearing, cross cylindrical roller bearing, cross tapered roller bearing and three row cylindrical roller bearing. The four-point contact ball bearing has a high static load capacity. The cross cylindrical roller bearing has high dynamic load capacity.
The slewing bearings are widely used in lifting machinery, mining machinery, construction machinery, port machinery, ship machinery and high-precision radar machinery and missile launcher and other large rotary devices.
Single row contact ball slewing bearing with a row of steel balls as the rolling body, the steel balls are separated by a single isolation block. The inner and outer rings are integral, and the steel balls are loaded by plugging holes. The steel ball is in contact with the rolling path at four points, and can bear axial force, radial force and tipping moment at the same time. It is the preferred product for small and medium sized slewing bearings with a diameter of less than 1800mm.
The structure of double row four point contact ball type slewing bearing is similar to that of single row contact ball type slewing bearing except that it takes two rows of steel balls as the rolling body and the two rows of steel balls have the same size. The inner and outer rings are integral, and the steel balls are loaded by plugging holes. It requires heavy duty, radial structure size is limited by the preferred products of the host.
Three-row roller slewing bearing is a kind of slewing bearing with high load-bearing capacity, which is mainly used in the operation of heavy load. Composed of three rings, the upper and lower rows of rollers are distributed horizontally to withstand the axial force and tipping moment in both directions. The radial force is borne by the third row of vertically arranged rollers.
The cross roller slewing bearing is similar to the single volleyball slewing bearing in that there is only one row of rolling bodies, the rolling bodies are cylindrical rollers, the axes of adjacent rollers are arranged in 90° cross arrangement, there are two raceway in the inner and outer rings, and the raceway section is linear. Half of the rollers bear the downward axial force, and half bear the upward axial force.
Double exclusion ball slewing bearings consist of upper and lower double rows of steel balls, inner and outer rings, isolation blocks and lubricating and sealing devices. However, the structure of double-displacement diameter slewing bearing, a three-piece slewing bearing, is relatively complex.
The light slewing bearing has the same structure as the ordinary slewing bearing. Widely used in food machinery, filling machinery, environmental protection machinery and other fields.