The middle bearing of the marine main engine is mainly used to bear the load of the shafting and ensure the normal operation of the shafting. Its lubrication mode is oil pan type automatic lubrication.
The oil slinger is immersed in the oil pool to provide sufficient lubricating oil for the oil filler bucket through the rotation of the intermediate shaft. Due to the rotation of the shaft, an oil wedge is formed between the shaft and Babbitt alloy to ensure the safe separation of the sliding surface. The friction occurs inside the fluid, so the friction coefficient is very small. The heat generated by friction of the bearing is taken away by the cooling water working in the cooling water chamber. According to GB/T14364-93, ship shafting sliding intermediate bearings are divided into three types: Type A, Type B and Type C.
1.Main technical parameters
a. Shaft diameter range 80-800mm
b. Shaft linear speed: 1.5-8m/s
c. Unit pressure ≤ 1.0MPa
d. Operating temperature of lubricating oil ≤ 65 ℃
e. Operating temperature of bearing bush ≤ 75 ℃
f. Cooling water volume 6-6.5L/min
g. Cooling water pressure 0.2-0.3MPa
2. Installation and maintenance
1. Preparation before installation
a. Open the packing box and check whether the bearing and accessories are complete according to the packing list. At the same time, check whether the bearing is damaged during transportation.
b. Check whether the connecting bolts of each part are loose.
c. The cooling water pipe interface is installed in place.
d. Installation tools and lubricating oil are complete.
2. Precautions
According to the use requirements of the bearing, the bearing shall be kept clean during installation, especially there shall be no impurities inside the bearing, and collision shall be avoided during installation. The installation and maintenance of bearings must follow the safety operation procedures.
3. Installation and operation instructions
3.1 Before the installation of bearings, preparations must be made for installation.
3.2 The base for installing the bearing must be fixed.
3.3 In order to avoid the moving bearing babbitt being subjected to tilting pressure, it is required that the correction of the bearing center must be observed. Check that the clearance between the four symmetrical points of the lower pad and the intermediate shaft is equal. The height of the bearing center is adjusted by the base plate and the bearing foot gasket. Before the bolts are tightened, the bearing base cannot be moved. The installation clearance of bearing must meet the drawing requirements.
3.4 The oil slinger must be firmly fixed on the shaft. No relative movement with the shaft is allowed during rotation. The distance between the oil slinger and the end face of the bearing pad must meet the requirements of the drawing.
3.5 The oil filler must be firmly installed, and the installation clearance between the oil filler and the oil slinger must be guaranteed.
3.6 After the installation of the bearing, connect the cooling water inlet and outlet to ensure smooth flow of water. The pipe joints shall be free of leakage. When the bearing is used, the cooling water flow must meet the requirements of GB/T14364-93 standard.
3.7 Inject oil into the bearing by observing the cover plate. The lubricating oil shall be sufficient, but shall not exceed the maximum oil level of the dipstick. The lubricating oil must be clean and free of impurities.
3.8 When using bearings, each leakage point must be carefully checked, with the emphasis on all leakage points buried below the oil level, and all leakage points must be eliminated immediately.
3.9 During field installation, it is allowed to apply a layer of sealant on the joint surface of bearing cover and bearing seat.
4. Maintenance and repair of bearings
4.1 During navigation, each shift must check the working condition and oil level of the bearing once. The operating temperature of bearing lubricating oil shall not be higher than 65 ℃, and the operating temperature of bearing bush shall not be higher than 75 ℃. For bearings with higher temperature, the causes shall be analyzed, and measures shall be taken to eliminate possible faults.
4.2 It is necessary to conduct a comprehensive inspection on the bearing once a year, remove the bearing, check the working surface and bearing clearance between the shaft and the bearing bush, and repair or replace the parts that cannot meet the use requirements.
4.3 The lubricating oil shall be replaced regularly according to the service condition of the bearing. Generally, the first oil change is for 1000h operation, and it shall be replaced every 4000h operation thereafter.
4.4 Drain oil through drain plug and refill new oil through observation hole.
5. Removal of bearing
a. Unscrew the drain plug and drain the lubricating oil;
b. Take out the oil level gauge;
c. Screw out the screws to separate the observation cover plate from the bearing cover, take out the oil filter screen, screw out the screws, and take out the oil filler;
d. Loosen the connecting bolts between the bearing pedestal and the bearing cover, take out the locating pins to separate the bearing pedestal from the bearing cover, adjust the bearing cover, take out the stop screws, and the lower bearing pad can be screwed out along the pad back;
e. Loosen the connecting bolts between the huff surfaces of the oil slinger to take out the oil slinger.
More about Marginal Self- Lubricating Bearings:
As a specialized manufacturer of self-lubricating bearings & bushings, Marginal Bearing is devoted to researching and producing new self-lubricating bearing materials.
Self-lubricating bearings, as the name suggests, provide their own lubrication during operation without requiring application of grease or oil lubricants. Due to this, self-lubricating bearings are also referred to as maintenance-free or greaseless bearings as they require no relubrication or grease.
An important distinction to make is that self-lubricating bearings are not bearings that come pre-applied with grease or oil lubricant – these bearings are instead referred to as prelubricated bearings. Prelubricated bearings will require relubrication at some point in their service life.
