Causes and treatment of sliding bearings
1. Reasons for the overheating of sliding bearings and their treatment methods
1.1 Oil ring damage causes the bearing to overheat
In the sliding bearing, the oil ring is often used to bring the oil between the rotating shaft and the bearing bush. If the oil ring is deformed or worn seriously, the oil ring will not rotate or rotate slowly, so that the oil between the shaft and the bearing bush is reduced and overheating occurs. Open the bearing housing cover and inspect the oil ring and replace it in time.
1.2 Lubrication problems cause the bearing to overheat
There are many types of lubricating oil. If the selection is improper, the oil is too dirty, and the amount of oil is not enough, the bearing can be overheated. The oil used for the sliding bearing is determined by parameters such as the power and speed of the motor. The relevant technical manual can be found.
1.3 bearing bushing processing causes the bearing to overheat
If the bearing bush is not well studied, the bearing bush is eccentric, and the bearing bush is seriously worn. Therefore, the contact angle between the rotating shaft and the bearing bush is too large, and the oil wedge cannot be formed, which may damage the oil body friction and cause the bearing bush to heat up; the scraper should be re-grinded or replaced. New bearing pads.
1.4 poor cooling causes bearing heat
The bearing shell is oily, causing poor heat dissipation or overheating due to the influence of the water temperature and the amount of water in the cooling water of the bearing. The pipe of the bearing housing should be kept clean and the cooling water should be unblocked, and the descaling should be carried out regularly; and the water quality and heat dissipation of the cooling water should be ensured.
1.5 oil circulation system failure causes bearing heating
Sliding bearings lubricated by pressure oil circulation often suffer from oil shortage and oil breakage due to oil pipe blockage or oil pump failure, causing bearing heat. In addition, the water temperature of the circulating cooling water of the pressure oil is too high, resulting in high pressure oil temperature; it also causes the bearing to heat up. The oil pipe should be dredged frequently, especially in summer, to ensure that the water temperature of the circulating cooling water is not high.
2, the bearing of the sliding bearing scraping
2.1 Bushings of bushings generally require grinding. The purpose of the bushing is to make the tile lining form a certain geometry, so that there is a wedge-shaped gap between the bearing bush and the journal to ensure that a wedge-shaped oil film can be formed between the friction surfaces when the journal rotates, so that the journal rises away from the tile lining. The oil film operates under the buoyancy to reduce the friction with the tile lining and reduce its wear and power consumption.
2.2 The inspection of the bearing bush is done by the coloring method. When inspecting with the coloring method, first clean the bearing bush, and check that the bearing bush should be free of cracks, blisters, and shelling. Then apply a thin layer of red dan evenly on the journal. Do not apply too thick, which will affect the inspection effect. After the shaft is painted with red dan, the bearing bush is mounted and rotated two times; then the bearing bush is taken out, so that the protruding portion on the bearing bush has a reddish color. The distribution of dyeing points requires 2-3 points per square centimeter in the angle of 60-70° of the center of the bearing bush. It should not be too much or too little; otherwise, it needs to be scraped.
2.3 The grinding of the bearing bush is carried out by dry grinding. Use a triangular scraper to first scrape the big point, scrape the dense point, and then scrape it in one direction, and scrape it twice if necessary. The direction of the knife marks between each pass should intersect to form a network or fish scale. After scraping, clean the tile surface and the journal with a white cloth and alcohol. Repeat the above-mentioned grinding method to make the dyeing point of the bearing bush thinner and more scraped until it meets the requirements.
2.4 No contact points are allowed outside the 70° angle of the center of the bearing bush. If they are, they should be scraped off and the sides of the bearing bush should be gradually expanded into a wedge-shaped gap.
Sixth, the conclusion
Whether the motor bearing can operate normally is directly related to the safe and efficient operation of the motor. Only when the inspection is strengthened and the motor bearings are properly maintained can the motor be safely operated.
