Engine Main Bearing

Marine diesel engine main bearings, there are 3 famous engine main bearings for propulsion engines and power generation engines. We are marine bearing parts manufacturer and supply high quality main bearings.

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Engine Main Bearing Description

Marine engines include heavy rotating components that exert varying forces on various parts of the engine crankshaft. One of the important load-bearing components of the crankshaft system is the engine main bearing.

Marine engine bearings are subjected to a variety of forces, including

• Air pressure is generated inside the lining.
• Dynamic inertial forces due to different reciprocating and rotating motions of engine parts.
• Centrifugal force because of different reciprocating and rotating motions of engine parts.
• Friction between crankshaft and bearings due to engine vibration.

The marine engine main bearing is designed to handle various forces while supporting the crankshaft rotating at high speed. Therefore, the material used to make the bearing is essential so that it can support the crankshaft journal and accommodate minor surface irregularities.

Engine Main Bearing alone can’t do the job. They will need a compatible lubricant to carry the load and allow the crankshaft journal to rotate smoothly. Lubricating oil allows the main bearing to withstand abrasive particles that create friction between the journal and the bearing.

Engine Main Bearing Material:

• White Metal
• Copper Lead and Lead Bronze
• Aluminum Tin

3 Types of main bearings:

There are 3 well-known engine main bearings used for propulsion engines, usually 2-stroke engines and power generation engines, they are 4-stroke engines, and they are as follows: main bearing function.

main bearing size chart

1. Lead Bronze Bearings

These bearings include the following layers:

• Flash layer: The top layer, 0.035mm thick, consists of tin and lead. It is used to protect the bearing from corrosion and dust when not in use. This layer flashes when the bearing is running.
• Nickle Barrier: The third layer consists of lead bronze, which has excellent anti-seize properties and is the main component in all layers as a bearing.
• Lead Bronze: The third layer is composed of lead bronze, which has an excellent anti-seizing property and is the principal component that acts as a bearing out of all layers.
• Steel back: The steel back is the final and support part of the bearing used for shape and support, all layers are glued together.

Piston pin bearings in four-stroke engines are made of lead bronze bearings and are also used for main bearings in small engines.

2. Bi-metal Bearing:

This bearing comprises the following layers:

• Aluminium Tin: The first layer of bi-metal comprises Al and Sn with a thickness of 0.5 to 1.3mm and this is the main element of this type of bearing.
• Bonding Layer: The bonding layer comprises aluminum and is 0.1mm thick. The main function of the bonding layer is to obtain a good bond between the shell and the top layer.
• Steel Back: The backing part is used for shape and support.

This type of bearing is used in 4-stroke main bearings

3. Tri-Metal Bearing:

These bearings are called tri-metal bearings because they include 3 main layers (excluding the flash layer) and a steel back. It comprises-

• Flash Layer: It’s the topmost layer, 1 micron thick, composed of tin and lead, and is used to protect the bearing from corrosion and dust when not in use. This layer flashes during bearing operation.
• Overlay: The second layer is made of white metal (tin-antimony copper), which is the main component of this type of bearing. Its thickness is 20 microns.
• Interlay: The third layer is used as an anti-corrosion layer for the cover layer. Its thickness is 5 microns.
• Lining: The lining layer between the interplay and the steel back is 1mm thick and composed of lead and bronze.
• Steel Back: The backing part is used for shape and support.

Main Bearing Spares:

Marine Engine Main Bearing Brands

We offer the Brands and Spear parts:

Engine Main Bearing

Marine Check Valves

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