Why does a tiny propeller propel a 10,000-ton ship? What is the design principle?

In fact, the small propeller is only relative to the ship itself, the propeller is not small, many ships are hundreds of tons of large parts of the propeller, such a large part of a few hundred revolutions of the rotating speed, coupled with more than 100,000 gas turbine or steam turbine drive, and the ship's streamlined design, run a 20 or 30 knots should not be difficult to do it The propeller's thrust is transferred through the propeller shaft (tail shaft) to the The propeller thrust is transferred to the center shaft through the propeller shaft (tail shaft). The simplest way is to set thrust bearings on the intermediate shaft that can withstand the axial thrust of the shaft system, so that the thrust of the propeller is transmitted to the ship through the thrust bearings, thus pushing the ship forward. We can see from the figure that the thrust bearing can not only withstand the axial thrust generated by the propeller, but also transmit it to the ship. It can also withstand the weight of the shaft itself (support); at the same time, as a support, it should also be able to withstand the radial load caused by the deformation or movement of the shaft tile.

How is the tremendous thrust of a ship's propeller transmitted to the ship? Able to propel hundreds of thousands of tons of ships thrust bearings can be divided into rolling and sliding type. The figure below shows a certain type of rolling thrust bearing. Its most important feature is that the rolling body under force is not parallel to the axis, but at an angle to the direction of the axis. Because of this angle, the bearing can withstand a certain axial force as well as a certain radial force. Although rolling thrust bearings have the advantage of low frictional resistance, they have the disadvantages of small load carrying capacity, high shock resistance and relatively poor reliability (compared with the sliding type), so they are only suitable for small ships.

The main components of the sliding thrust bearing are the thrust ring and thrust block. Its working principle is: the propeller's thrust is transferred to the intermediate shaft through the propeller shaft (tail shaft), and then transferred to the thrust shaft by the intermediate shaft. The thrust ring on the thrust shaft transmits the axial thrust to the thrust block on the bearing seat, and finally transmits it to the hull through the bearing seat. In order to meet the need of direction change, both sides of the thrust ring should be equipped with thrust blocks and adjustable clearance device. The contact surface of the thrust ring on the thrust shaft and the thrust block on the bearing seat is the working surface of sliding friction, so the thrust block should also be cast with white alloy on the contact surface of the thrust ring to improve wear resistance and ensure good lubrication.