Home / News / Preventive measures for early damage of sliding bearings

News

Preventive measures for early damage of sliding bearings

Update:28-10-2020
Summary:

1. Improve bearing design and manufacturing process Whe […]

1. Improve bearing design and manufacturing process

When designing or selecting a bearing, the thermal balance of the bearing should be considered to control the temperature rise. In terms of structural design, an oil inlet hole is opened from the top of the upper bearing bush (non-loading area) of the bearing to allow lubricating oil to be introduced from the non-loading area; an oil groove is opened on the inner surface of the bearing shell along the longitudinal or transverse direction with the oil inlet as the center, which is conducive to lubrication The oil is evenly distributed on the journal to control the temperature rise. According to the working conditions of the bearing, the bearing bush material must have the following properties: small friction factor; good thermal conductivity, low thermal expansion coefficient; strong wear resistance, corrosion resistance and anti-adhesive ability; sufficient mechanical strength and plasticity

Sex. Therefore, the material of bearing bush can be babbitt alloy. Babbitt alloy can work well under stable load, but it is prone to cavitation under unstable load, so it is not suitable for use in high-power engines. High-tin-lead-based alloys and low-tin-lead-based alloys have high strength and hardness, and have strong anti-fatigue and anti-cavitation capabilities, and are effective in high-power internal combustion engines. In addition, changing the round oil groove bush to a semi-circular oil groove or part of the oil groove bush can not only improve the lubrication state of the sliding bearing of the diesel engine, but also increase its carrying capacity.

2. Improve bearing maintenance and assembly quality

Improve the quality of bearing articulation, ensure that the back of the bearing is smooth and spotless, and the positioning bumps are intact and undamaged; the self-opening amount is 0.5 ~ 1.5 mm, which can ensure that the bearing bush is tightly fitted with the bearing housing hole by its own elastic force after assembly; Each end of the upper and lower two pieces of the bearing in the bearing seat should be 0.03~0.05 mm higher than the bearing seat plane. The higher amount can ensure that after the bearing cap bolts are tightened according to the specified torque, the bearing and the bearing seat are closely matched to produce enough Friction self-locking force, the bearing will not loosen, the heat dissipation effect is good, and it can prevent the bearing from ablation and wear.

 

 

In addition, pay attention to checking the machining quality of crankshaft journals and bearings during assembly, and strictly implement the repair process specifications to prevent incorrect installation due to improper installation methods and uneven torque of bearing bolts or non-compliance with regulations, resulting in deformation, bending and stress concentration. Cause early damage to the bearing.

3. Use and maintain the engine correctly

Strengthen the cleaning and maintenance of the oil filter and crankshaft ventilation device, and replace the filter element in time; ensure the normal operation of the engine cooling system, control the normal temperature of the engine, and prevent the engine from "boiling". It is strictly forbidden to drive without cooling water; select the correct fuel, Accurately adjust the gas distribution phase and ignition timing to prevent abnormal combustion of the engine; check and adjust the technical condition of the crankshaft and bearings in time.

4. Reasonable selection and filling of lubricating oil

In the process of use, lubricating oil with low oil film surface tension should be selected, which can effectively prevent bearing cavitation; the viscosity grade of lubricating oil cannot be increased at will, so as not to increase the coking tendency of the bearing; the lubricating oil level of the engine must be within the standard range ; Lubricating oil and lubricating tools must be clean to prevent any dirt and water from entering; pay attention to regular inspection and replacement of lubricating oil to avoid being contaminated by moisture and other impurities; lubricating oil should be free of pollution and sand in the place to prevent everything Contaminants are mixed in; it is forbidden to mix lubricating oils of different qualities, different viscosity grades and different types of use. The sedimentation time before filling should generally not be less than 48 h. Strictly control the injection quantity to prevent excessive oil level.

https://www.cnzxzc.com/

0
Views: 25