Selection rules for marine accessories

The role of marine accessories should be support, that is, literally used to support the shaft, but this is only part of its role, the essence of support is to be able to bear radial loads. It can also be understood as it is used to fix the shaft. The automatic selection of bearings is included. It is to fix the shaft so that it can only achieve rotation, while controlling its axial and radial movement. The motor cannot work at all without bearings. Because the shaft may move in any direction, and the motor is required to only rotate when it is working. Theoretically speaking, it is impossible to achieve the role of transmission. Not only that, but the bearing will also affect the transmission. In order to reduce this effect, good lubrication must be achieved on the bearings of the high-speed shaft. Some bearings are already lubricated, which are called pre-lubricated bearings. Most bearings must have lubricating oil. When running at high speeds, friction will not only increase energy consumption, but even more frightening is that it is easy to damage the bearings. The idea of turning sliding friction into rolling friction is one-sided, because there is something called a sliding bearing.

The thermal spraying process requires disassembly of the entire equipment and requires a lot of manpower and material resources. Machining is required in the repair process of thermal spraying. Due to the large equipment, the requirements of marine bearings for lathes are also very high. The repair process of thermal spraying has a high repair accuracy, but it is difficult to repair large equipment and cannot be repaired on site, resulting in a long repair period and high repair costs, which are often unacceptable for enterprises. The traditional repair welding machine processing and repairing process also faces the problem that the repair cannot be completed on site, the repair cycle is long, the overall cost is high, and the long-term shutdown and production shutdown will cause huge economic losses to the enterprise. Whether it is thermal spraying or repair welding machine processing technology, there is a problem of thermal stress concentration during the repair process, which causes the shaft to deform or there is a hidden danger of shaft breakage.

Since the lubrication surface of the intermediate bearing is not absolutely smooth, there are various rough peaks of different heights. Therefore, the lubrication status of the intermediate bearing can be judged objectively by the Z small film thickness ratio Hm. The Z small film thickness ratio Hm is defined as the ratio of the Z small oil film thickness of the intermediate bearing to the comprehensive roughness of the two lubricating surfaces, which is dimensionless. Generally speaking, when the Z film thickness ratio is Hm>>3, it indicates that the intermediate bearing has better lubrication performance. The marine intermediate bearing is in a full-film fluid lubrication state, that is, the lubricating oil film fills the gap between the outer surface of the journal and the inner surface of the bearing bush, and the two lubricating surfaces It is completely separated by the oil film and no contact occurs.

The use of standard polymer composite materials for repair can well reduce the loss of additional costs, and the repair time is short and the repair cost is low. On-site repair, simple process, no need to invest a lot of manpower and material resources, greatly improve maintenance efficiency and shorten downtime

Intermediate bearing is a kind of bearing, which is widely used in mechanical equipment. The intermediate bearing is the main supporting unit of the ship's shafting system, and it bears a relatively large load during the working process. The performance of the intermediate bearing will directly affect the dynamic performance of the ship's propulsion system. Therefore, the lubrication performance analysis of the intermediate bearing is carried out to effectively predict the lubrication status of the bearing, and the bearing structure parameters are optimized according to the design requirements and analysis results to reduce the friction resistance of the intermediate bearing, reduce the vibration and noise of the shaft system, and improve the shaft transmission Efficiency and reliability, reducing material wear and extending service life are all of great significance.

The small oil film thickness and film thickness ratio of the intermediate bearing Z under different speed conditions: When the speed is small, the small oil film thickness of the intermediate bearing Z is smaller. As the journal speed increases, the thickness of the Z oil film increases, showing an upward trend. This is because with the increase of the journal speed, the relative movement speed between the two lubricating surfaces of the bearing increases, and the dynamic pressure effect of forming the lubricating oil film is enhanced, which is beneficial to the formation of the lubricating oil film, thereby increasing the bearing capacity of the lubricating oil film in the bearing area. The thickness of the Z small oil film increases accordingly.