Definition and Function

The sliding watertight lower rudder support is a key component of the ship's rudder system, located at the lower part of the rudder stock. It mainly has two important functions: one is to provide support for the rudder stock, bear the weight of the rudder stock and the partial radial force generated by the rotation of the rudder blades; The second is to ensure water tightness, prevent seawater from entering the ship from the bottom of the rudder, and ensure the safety of the ship's interior and the normal operation of equipment.

Structural composition

Sliding bearing part:

This is the core support structure of the lower rudder support. Usually composed of wear-resistant materials such as bronze, Babbitt alloy, etc. The inner surface of the bearing shell is in close contact with the rudder stock, and its shape and size are well adapted to the rudder stock to ensure stable sliding inside the bearing shell. The bearing shell needs to have good wear resistance, as the steering wheel will constantly rub against it during the turning process.

Water tight sealing components:

Sealing components are the key to achieving water tightness. Generally includes rubber seals, sealing glands, etc. Rubber seals are usually made of materials with good elasticity and resistance to seawater corrosion, such as nitrile rubber. The shape and installation method of the seal enable it to tightly fit between the rudder stock and the outer shell of the lower rudder support, preventing seawater from entering. The sealing cover is used to fix and compress the sealing element, and is connected to the main structure of the lower rudder support through bolts and other means. Adjusting the tightening degree of the cover can control the clamping force of the sealing element on the rudder stock.

Shell and installation structure:

The shell mainly serves to protect internal components and connect the ship structure. It is usually made of metal material, such as cast iron or steel, with sufficient strength and stiffness to withstand the force transmitted by the rudder stock. The outer shell is installed on the rudder support seat at the bottom of the ship through welding or bolt connection, ensuring the stability of the entire lower rudder support during the ship's navigation.

working principle

When the rudder stock works in the sliding water tight rudder bearing, the weight and partial radial force of the rudder stock are borne by the bearing shell of the sliding bearing part. The rudder stock slides inside the bearing shell, and the material properties of the bearing shell and the appropriate clearance design enable the rudder stock to rotate flexibly. At the same time, the waterproof sealing component plays a role. The rubber seal tightly adheres between the rudder stock and the housing under the pressure of the sealing cover. Due to its elasticity and tight fit, even during the rotation of the rudder, it can effectively prevent seawater from entering the ship through the gap between the rudder and the lower rudder support. For example, when a ship turns, the rudder stock drives the rudder blades to rotate, and the sliding bearings of the lower rudder support ensure the smooth rotation of the rudder stock, while the sealing components remain sealed at all times.

advantage

Good water tightness: Through specially designed sealing components, the sliding water tight lower rudder support can effectively prevent seawater from entering the ship, which is crucial for the safety of the vessel. It can reliably maintain water tightness performance during long-term navigation of ships and under different sea conditions.

Simple sliding support method: The design of sliding bearings makes the support method of the rudder stock relatively simple. This design has relatively low manufacturing process requirements and can provide stable support for the rudder stock under normal working conditions, ensuring the rotational flexibility of the rudder stock.

Durability and stability: The bearing shell is made of wear-resistant materials and the sealing material is resistant to seawater corrosion, making the sliding watertight lower rudder bearing highly durable in harsh marine environments. Its structural design ensures stability during ship navigation and reduces the possibility of rudder system failure caused by component damage.

Disadvantages and countermeasures

Wear and aging of seals: Due to the relative motion between the seal and the rudder stock, the seal is prone to wear and aging after prolonged use, resulting in a decrease in water tightness. The response measure is to regularly check the wear of the seals and replace them in a timely manner for severely worn or aged seals. Meanwhile, sealing materials with better quality, stronger wear resistance, and aging resistance can be selected.

High sliding friction loss: Compared with rolling bearings, sliding bearings have a higher sliding friction coefficient, which may result in significant friction loss during the rotation of the rudder stock. In order to reduce friction losses, on the one hand, it is necessary to ensure good lubrication of the bearing, which can be achieved by adding lubricating oil or using self-lubricating materials to make the bearing; On the other hand, it is necessary to ensure that the clearance between the rudder stock and the bearing shell is reasonable, to avoid increasing friction due to too small clearance or affecting support stability due to too large clearance.

Application scenarios

Bottom support of rudder system for various types of ships: Whether it is a large ocean going vessel or a small to medium-sized inland waterway vessel, as long as the water tightness and stable support of the bottom of the rudder stock need to be ensured, the sliding water tightness bottom rudder support is applicable. It plays an indispensable role in the ship's rudder system and is an important component to ensure the normal navigation and turning of the ship.