Large open gears are commonly used in some industrial transmission equipment of raw materials, such as rotary kiln in cement plant, cement clinker ball mill, mine ball mill, coal mill in power plant, chemical dryer, granulator, drum pulper in papermaking industry, etc. The characteristics of gears of these equipment are: large size (the machining accuracy of large and small gears is different (usually the machining accuracy grade of pinion is higher than that of large gear). These large module gears are difficult to process and heat treat, which makes the manufacturing cost of open gears high. These equipment are usually the key equipment of the factory.

Therefore, on the basis of ensuring its safe and stable operation, how to do a good job in the lubrication and maintenance of open gear, so as to make the equipment reach a better service life, save consumption, be conducive to environmental protection and human health, and facilitate on-site management has become one of the more concerned problems. A team went to the cement plant for on-site investigation and found some problems caused by improper lubrication of the open gear of the rotary kiln, such as pitting corrosion, abrasion and wear of the open gear of the rotary kiln. After that, the team makes judgment on the cause of damage and subsequent improvement suggestions.

The rotary kiln equipment of cement plant adopts single pinion drive. Straight tooth lubrication is oil pool lubrication. Now a brand of gear opening lubricant is used. At present, the pinion pitch circle line is lower, and the pitting corrosion is more serious, with certain wear. The gear tooth surface pitting corrosion is more serious, and there are scratches.

In the process of gear transmission, the contact stress changes in a pulsating cycle at any point on the gear from entering meshing to leaving meshing. When the contact stress and repetition times exceed a certain limit, small fatigue cracks appear on the tooth surface, and the crack propagation causes the metal to peel off and form pitting corrosion. It first appears near the pitch line, because the attachment of the pitch line is a pure rolling area, resulting in fatigue cracks.

The raw lubricant can not form a good protective oil film, which leads to the fatigue of the accessory materials of the tooth surface circle and the formation of fatigue cracks and solvents. Lubricant enters the human body and forms pitting corrosion. The cause of the scratch is the rupture of the oil film and the entry of pollutants into the human body.

Improvement suggestions on lubrication of open gear of rotary kiln

1. Oil infiltration into the fracture will aggravate the propagation rate of pitting corrosion. In order to slow down the expansion speed of pitting corrosion, it is recommended to replace high viscosity gear opening lubricant, such as yourun gear opening lubricant, which can increase the thickness of lubricating oil film, increase the bearing capacity and reduce the amount of oil penetrating into pitting cracks, so as to slow down the expansion speed of pitting corrosion and alleviate the generation of scratches.

2. Try to better seal the large gear ring of the rotary kiln, reduce the entry of water, dust and other pollutants, and regularly replace and test the oil quality, so as to replace the oil in time and ensure the normal use of the equipment. When changing oil products, clean the crude oil as much as possible.