Large Single Row Cross Roller Slewing Bearing for Deck Crane

Large Single row Cross Roller Slewing Bearing for Deck Crane

Slewing ring bearings can be widely used for marine crane and deck crane.

At present, with the development of offshore oil drilling platform industry, higher and higher requirements are put forward for large lifting equipment (deck cranes) used for platform installation and maintenance, mainly including:

1. The requirements of basic functional parameters are continuously improved. The lifting capacity of a single machine is basically more than 1000t, the maximum operating range can reach nearly 100 meters, and the lifting height of underwater operation can reach 2000 meters, and the crane is required to be able to rotate fully.

2. Higher requirements are also put forward for the effective operation area of the deck of the crane ship. Users often require that the smaller the area of the ship deck occupied by the lifting equipment, the better.

3. In addition, some users also require reducing the tail turning radius and set the driving mechanism inside the rotary column. In order to reduce the overall size of the crane, it is not allowed to reduce the tipping torque by adding balance weights.

In short, the development of offshore engineering cranes requires their performance to be more and more superior and their form to be more and more concise. These requirements pose a severe test to the design and manufacture of crane slewing bearing devices. To meet these requirements, the slewing bearing is usually of the rotary column type and installed below the ship deck.

At present, the rotary column slewing bearing is usually composed of a group of upper rollers and a bottom centripetal thrust bearing. The upper roller bears the horizontal force generated by the overturning moment, and the bottom centripetal thrust bearing bears both horizontal force and vertical force.

The maximum lifting torque of the large-tonnage full-swing crane can reach more than 100000 tons. In this case, the horizontal and vertical forces of the slewing bearings are relatively large, and the load can reach more than 3000 tons.

For the upper roller, there are great difficulties in the scheme design. The large roller slewing bearings capacity of a single roller is limited. In order to achieve the bearing capacity, the method of increasing the diameter and number of rollers should be adopted, resulting in the roller occupying too much deck space, which is unacceptable to users; In addition, the friction coefficient between the roller and the rail is relatively large, resulting in a corresponding increase in the slewing resistance, resulting in an increase in the slewing drive power.

For the bottom centripetal thrust bearing, which bears the horizontal force and vertical force two-way load, under the existing industrial conditions, it is not possible to design and manufacture the centripetal thrust bearing that can meet the above load capacity requirements. In the existing form of rotary column slewing bearings, the centripetal thrust bearing is also divided into a radial spherical bearing and a self-aligning thrust bearing. The two bearings bear the horizontal force and the vertical force respectively. In order to ensure the automatic positioning effect, the spherical centers of the two bearings coincide at a point. It is generally applicable to occasions with small load and size, and the accuracy can be guaranteed by machining. After the size becomes larger, due to the limitation of machining capacity, manufacturing and installation errors and the influence of structural deformation, it is impossible to realize the concentricity of the two bearings, which may easily lead to the partial seizure of the bearings during operation and the inability to rotate, resulting in the early damage of the bearings, with serious consequences.