Abstract: This paper will analyze and explore the main strategies to prevent sliding bearing damage, hoping to provide some help and suggestions for relevant personnel to better avoid sliding bearing damage.
Key words: injury prevention; Sliding bearing; Mechanical vehicles
Introduction
When the sliding bearing is in working condition, friction will occur between the bearing pad and journal due to contact with each other, resulting in wear, heating, seizure and other conditions on its surface. The specific damage includes corrosion of the pad surface, corrosion of the journal surface, strain of the journal surface, fretting wear of the pad back, pulling up of the bearing surface, peeling of the pad surface, burning of the bearing pad, wear of the bearing, etc. Therefore, It is of practical significance to study the main strategies to prevent sliding bearing damage.
1. Reasonably assemble and maintain the bearing
The staff should strengthen the work of hinged bearing, improve the quality of hinged bearing, make the back of bearing free of spots, show smooth characteristics, and have a very complete locating bump. The bearing spring opening shall be reasonably set to ensure that the bearing bush can closely fit the bearing seat hole with elastic force after the bearing is assembled. The height of the upper and lower bearing pads of the bearing block shall be determined according to the actual situation, so that they can tighten the bolts of the bearing cover according to the torque requirements, so that the bearing block and the bearing can closely cooperate to form a large amount of friction self shrinking force. If the bearing is very compact and has strong heat dissipation, its wear and ablation prevention effect will be better. At the same time, in the process of assembling bearings, the inspection of crankshaft bearings and journals shall be strengthened, and the inspection shall be carried out in strict accordance with the repair specifications and processes, to avoid problems such as bearing bolts not meeting the requirements, uneven torque, non-standard installation, etc. caused by incorrect installation methods, and to prevent bearing damage caused by stress concentration, bending and deformation, etc.
2. Use bearings correctly
First of all, do not let the engine work for a long time when it is in the condition of low speed and heavy load. Under the condition of low speed and heavy load, the engine bearing will reach the boundary lubrication state, especially after the engine speed is reduced to the chattering point, due to the influence of the chattering vibration wave, different metals are easy to contact each other. In order to make the bearing have a longer service life, it is necessary to ensure that when the engine is in low speed and heavy load conditions, the speed should be controlled at the minimum as far as possible.
Secondly, if the bearing is very short of lubricating oil, excessive and large amount of wear will also occur, sometimes leading to the occurrence of bush burning. From this, we can see that when using machinery, the workers need to check the oil level of the oil pan frequently, and add oil if the height is not enough. When using the machine, the staff needs to check the quality of lubricating oil regularly. Generally speaking, during the use of lubricating oil, the lubricating oil will slowly deteriorate, mainly due to fuel dilution and mechanical impurities pollution. When the lubricating oil depreciates, it will greatly reduce the lubricating effect and bring varying degrees of harm to the machinery. This requires the staff to regularly conduct a comprehensive and careful inspection of the quality of the lubricating oil, and replace it if necessary.
3. Timely adjust and check the bearing
Bearing inspection mainly includes disassembly inspection and non disassembly inspection. Among them, inspection without disassembly refers to auscultation work based on the sound made by staff experience or corresponding equipment without disassembling the machine. If the bearing is damaged, there will be abnormal sound during its operation, resulting in knocking sound. For the main bearing, the knocking sound is relatively heavy, which will become louder and louder with the increase of load and speed, especially when the accelerator increases instantaneously, and the engine will vibrate. After the gap increases, the bushing burns, and the alloy falls off to a certain extent, no matter what the load and speed are, there will be knocking noise. When determining the source of the bearing noise, the staff mostly judge according to their own experience, or make the front and rear cylinders of the bearing cut off. If the noise decreases at this time, it means that the bearing makes a noise. At the same time, compared with the knocking sound of the main bearing, the knocking sound of the connecting rod bearing is slightly lighter. When listening from the outside of the engine body, it is like the sound of a refractory brick being knocked by a small hammer. It is solid and short. To enhance the effect of stethoscope, the staff can use the machine stethoscope.
Disassembly inspection is generally carried out at the same time as technical repair and maintenance of bearings, or after finding specific problems without disassembly inspection. The staff can effectively identify the condition of bearing damage by means of disassembly inspection. When checking the clearance of the connecting rod bearing on the vehicle, drain the engine oil first, remove the connecting rod end cap and oil pan, and then take out the bearing. If the antifriction alloy is free from cracks, falling off, burning, etc., the impurity layer on its surface shall be scraped off with the help of a scraper, and the oil hole and oil groove shall be corrected to show the new antifriction alloy layer, and then the new antifriction alloy layer shall be installed back according to the disassembly steps, and the gap shall be adjusted and checked.
4. Adjust the design process
During the design and selection of bearings, their thermal balance should be considered and the temperature rise should be well controlled. When in the state of friction, the bearing will have some power consumption due to the friction generated in the lubricating oil, which is easy to cause the temperature rise of the bearing when it is converted to heat. After the lubricating oil changes the clearance and reduces the viscosity, the babbitt in the bearing will be softened, and when the situation is serious, the safety accident of burning pads and holding shafts will occur. It is easy to see from here that when designing the structure of the bearing, the oil inlet hole should be located at the top of the upper bearing pad, so that the lubricating oil can enter through the non load bearing area. When opening the oil groove, the oil inlet hole shall be taken as the center, which shall be carried out horizontally or longitudinally along the inner surface of the bearing pad, so that the lubricating oil can be distributed more evenly on the journal and play a role in controlling the temperature rise.
According to the actual working condition of the bearing, the bearing material shall have strong plasticity, mechanical strength, anti bonding ability, corrosion resistance, wear resistance, thermal conductivity, and small thermal expansion coefficient and friction coefficient. From this, we can see that babbitt is a good choice for bearing materials. If babbitt alloy is used, it can work better when the load is stable, and cavitation is easy to occur when the load is unstable, so it is not suitable for high-power generators. In contrast, low tin lead based alloys and high tin lead based alloys have higher hardness, strength, cavitation resistance and fatigue resistance, which will have good effects when applied to high-power engines.
Conclusion
In a word, it is of great significance to study the main strategies to prevent sliding bearing damage. Relevant personnel shall, according to the specific causes of sliding bearing damage, effectively eliminate sliding bearing faults by reasonable assembly and maintenance of bearings, correct use of bearings, timely adjustment and inspection of bearings, adjustment of design process, etc., so as to prolong the service life of bearings and create more benefits.
More about Sliding bearing:
Sliding bearing is a bearing that works under sliding friction. The sliding bearing works stably, reliably and without noise. Under the condition of liquid lubrication, the sliding surface is separated by the lubricating oil without direct contact, which can also greatly reduce the friction loss and surface wear, and the oil film also has a certain vibration absorption ability. However, the starting friction resistance is large. The part of the shaft supported by the bearing is called the journal, and the parts matching the journal are called the bearing bush. In order to improve the friction properties of the bearing surface, the antifriction material layer cast on its inner surface is called bearing lining. The materials of bearing bush and bearing liner are collectively referred to as sliding bearing materials. The application of sliding bearing is generally under the condition of high speed and light load.
Compared with rolling bearing, the utility model of sliding bearing has the advantages of convenient disassembly, simple structure, quiet operation and can bear medium and large impact load.
Marginal is a company mainly engaged in sliding bearings. Welcome all of you to contact us to know more!
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Applications covered are automotive industry, construction machinery, plastic manufacturing machinery, OA machinery, material handling equipment, dock side machinery and hydraulic transmission parts. In brief, our bearings can be used wherever there is rotation or linear motion between mechanical parts where lubricating is not allowed or external lubricating accessibility is limited.
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