China Best Tower Crane Slewing RIng Bearing

1.Tower Crane Slewing Ring Bearing

Underwater slewing bearing and slewing bearing, the process is very complex, the manufacturing cost is high, there are many high-precision and high-precision matching dimensions, the theoretical design life is long, and the reliability and stability requirements match the overall design life. In addition, waterproof seals and special materials are used. core process indicators.

As shown in the figure in terms of precision design and manufacturing process,

Using four-point contact ball bearings and double-row ball bearings, the theoretical design and 3D diagrams are shown as follows:

The structure of the channel, the contour shape and the ideal state of the contact points are shown in the figure. The channel of the double-row ball bearing has eight contact points, and the actual machining accuracy is required to be higher.

At this time, the level of CNC machine tools and operators is extremely important, which determines the high precision level of the entire bearing.

Waterproof sealing is absolutely the core process and key technical index of the entire tower cranes slewing ring bearing. The sealing adopts three sealing strips, and the sealing contact part adopts ceramic technology to enhance air tightness, improve lubrication protection and wear resistance, fatigue resistance, corrosion resistance and rust resistance. .

The two O-rings are the highlight of the design, which once again achieves airtightness in the first-line protection, making the waterproof seal worthy of the name and achieving the patent of beautiful utility model.

2.Selection, maintenance and replacement of slewing bearing of port gantry crane

As the core component of the port gantry crane, tower cranes slewing ring bearing should be reasonably selected, installed and used correctly, effectively prevent and maintain faults, prolong the service life of the slewing bearing, improve the safety of equipment use, and increase economic benefits.

The slewing bearing is the core component of the port gantry crane (hereinafter referred to as “gantry crane”), which can bear the combined loads such as axial load, radial load and overturning moment at the same time.

Due to the complex load, difficult replacement, and high maintenance costs, the door crane is generally selected according to the 20-year design service life, but it is often not guaranteed in actual use.

In recent years, large-tonnage gantry tower crane slewing ring bearing in various coastal ports have successively suffered slewing bearing failures, causing huge economic losses to enterprises. Therefore, it is particularly important to effectively select, install, use, maintain and extend the service life of the slewing bearing.

Reasonable selection of slewing bearing

The utilization level of the port door crane is U8, the load state is Q4, and the working level is A8. It has the characteristics of high utilization rate, large load bearing, fast running speed and high working level.

According to the tower crane slewing ring bearing load and life calculation method, the static load safety factor fs of the grab gantry crane is 1.45, the life load factor fe is 1.7, and the service life Lf during full rotation is 150,000 revolutions. However, the actual operating rotation range of the iJ machine is mostly within 180° left and right of the sea side.

The high-strength reciprocating operation and the combined load will aggravate the fatigue of the bearing within a certain range. Therefore, the selection and installation of the slewing bearing has strict requirements. requirements.

At present, the structural forms widely used as tower cranes slewing ring bearing mainly include four-point contact ball slewing bearings, double-row reducing ball slewing bearings, crossed cylindrical roller slewing bearings and three-row cylindrical roller combined tower cranes slewing ring bearing.

Generally, when the bearing rotation diameter and section size are basically the same, the static and dynamic load carrying capacity of the three-row cylindrical roller combination slewing bearing is the largest, which reduces the load of each roller compared with the crossed cylindrical roller slewing bearing.

Compared with the double-row reducing ball slewing bearing, the load is changed from point contact to line contact, which reduces the contact stress. According to the working conditions of port gantry cranes, the structure of this bearing is most suitable for the use requirements of port gantry cranes.

Correct installation of tower cranes slewing ring bearing

As a large thin-walled ring component, the tower cranes slewing ring bearing must be rigidly connected with the gantry cylinder and the flange of the slewing plate. Warpage deformation occurs, so the flange must be machined to ensure accuracy.

Taking the 132.50.4500.03 type slewing bearing often used in 40T door cranes as an example, the diameter of the center circle of the rolling body is 4500mm, and the flatness of the flange plate is required to be 0.30mm at most, and this value is only allowed to appear in the range of 180 – – times, and A steady rise or fall without waves.

The inclination of the radial width is less than 0.25, and the surface roughness Ra reaches 3.2. At the same time, the flange should also have sufficient axial and radial stiffness to ensure that the deformation in the vertical and horizontal directions is within the specified limits.