Zhongtiaoshan non-ferrous metal mining company copper mine valley annual ore processing 4.1 million t, crude mineral processing equipment two pieces, some are KK! 900A60 gyratory crusher, two stage is P2100 x1500 jaw crusher, ore daily processing are In the 5th 900A60 gyratory crusher, three main shaft fracture accidents occurred, and the normal service life was 35 years. The value of the main shaft was 320,000 yuan, accounting for 8B of the total equipment price. The multiple fractures of the main shaft increased the operating cost of the equipment. The engineering and technical personnel of equipment management should carefully find out the reasons and take effective measures to reduce or even eliminate the occurrence of broken shaft accidents, gradually reduce production costs, and further improve equipment management.
2 Analysis of main shaft fracture phenomenon Wencao No.: Rencheng County, West Province, senior engineer, engaged in equipment management.
2.1 The force of the crushing cone and the main shaft (1) The crushing force and the bearing force of the equipment in normal operation. It can be seen that in the ideal state, the crushing force P acts at 1/3 of the height of the crushing cone (from the plane of the discharge port), and the empirical formula is used to calculate the breaking force P. n the number of revolutions per minute of the eccentric bushing , that is, the number of times the fracture cone is swung n=125r/min; measured; the eccentricity at the average radius of the inner hole of the e-eccentric bushing, e=23.37mm;! The ideal state of the crushing force P causes the reaction force of the inner surface of the eccentric bushing is Acts in the middle of the eccentric bushing. The action line is not in the plane formed by the axis of the crushing cone and the center line of the body, but is inclined at an angle. According to the wear condition of the eccentric bushing, the value is =30°; during the operation of the gyratory crusher, the inner and outer surfaces of the eccentric bushing are semi-liquid friction, so take the /0.03 crushing force P and the reaction force P of the eccentric bushing to the suspension point. The moment balance equation is: P/=Pi/i The operating state of the crushing cone is a kind of dynamic balance. The combined force of the self-weight and the crushing force of the crushing cone is the same as the reaction force of the eccentric bushing on the main shaft and the reaction force of the suspension device to the main shaft. Equal, opposite directions.
The crushing force P and the size and direction of the self-weight G of the crushing cone are known. The angle between the crushing cone surface and the centerline of the cone is 10, and the magnitude and direction of the resultant force F can be obtained by the graphic method. That is, the magnitude and direction of the reaction force of the eccentric bushing have been obtained in front of F=638, and the reaction force of the eccentric bushing on the main shaft is equal and opposite. Therefore, the same method can be used to obtain P2=481180N. (2) Analysis of the crushing force of the equipment under abnormal conditions. As shown in the figure, the main analysis and calculation of the large ore makes the crushing force of the body's fracture zone move upwards. Therefore, the value of the parameters M, /1, e, !, f, r, and 7 are basically unchanged. You need to change the size of /(/").
According to the specific conditions of the equipment operation / "take the above known parameters into the formula P" =, also use the graphical method can be obtained: F "= 931 or more results indicate that the body is in motion (in the case, due to large ore to break the belt When the crushing force is increased, the combined force of the main shaft must increase, and the reaction force of the eccentric bushing on the main shaft hardly changes, and the reaction force of the suspension device on the main shaft is greatly increased, which will inevitably lead to a large impact on the main shaft. The load, even the weakest part of the fixed liner thread undercut, breaks.
2.2 Influence of production process conditions Since the beginning of 2003, copper ore 810 (870 mining to 690 level 4, 5 ore body, due to changes in ore composition (ore hardness from 2.0 to 2.8 increased to 2.5 to 3.5), and no The reason for the unloading of the drop is that the large ore is increased, which seriously affects the normal operation of the coarse crushing equipment, causing the spiraling crushing belt to move up, and the stress state of the main shaft changes significantly. It can be seen from the force analysis and calculation that the crushing belt is on the upper part. The displacement doubles the crushing force, and the force on the spindle also multiplies, causing the spindle to be overloaded and then broken.
2.3 The influence of the spindle material The strength of the spindle depends largely on its material. The material of the main shaft of the copper ore smelting plant is 45+ carbon structural steel, which is characterized by high strength and good Machinability, toughness and plasticity are generally poor, and hardenability is poor. When the shaft member of this material is subjected to an impact impact, it has no good toughness and plasticity, and the strength is far from satisfactory. Usually the main shaft is injured and suddenly breaks in severe cases.
2.4 Equipment operation management factors In the process of calculating the crushing force, there are many factors affecting the crushing force, such as the degree of aging of the body, the degree of wear of the suspension components, the motor power, the point of action of the eccentric bushing, the size of the nugget, and the eccentric bushing. The degree of wear and the lubrication of the inner diameter of the eccentric bushing are all closely related to the operation and management of the equipment. It is better to master the use of the main components. Through the efficient management of the equipment, it can reduce various faults to a large extent. happened.
3 Measures taken 3.1 Improvement of production process conditions In the case of the existing mining production process of copper ore mine, the hardness and size of the ore block are the objective factors affecting the operation of the coarse crushing equipment. Therefore, it is necessary to adopt an appropriate method to gradually improve the mining production. Processes, such as scientific measurement of ore management, reasonable amount of fire attack materials, etc. At the same time, the ore dressing plant has a scientific process of mineralization, that is, the two sections of the crushing mine can be fed to each other before the crushing, as long as one of the coarse crushing equipment needs to be parked for overhaul, overhaul, routine maintenance or fault handling, and the other When the equipment is started normally, the supply of the two systems can be guaranteed in a short period of time. In August 2004, due to the occurrence of a broken shaft accident, the ore dressing plant continued to divide the mine for more than one month, which greatly reduced the accident loss. Therefore, in the past two years, it was thick. In the case of broken equipment accident parking, a good mining process ensures the continuity of production and ensures the company's annual production and operation objectives.
3.2 Material changes In recent years, with the development of steel manufacturing and metal processing manufacturing industry, many alloy structural steels are widely used in the processing industry. The spindle material of the gyratory crusher recently signed by the factory is alloy structural steel 30C-2M/V. The steel has the characteristics of high strength, high toughness, good cutting performance, moderate cold deformation plasticity, good hardenability and good welding performance, and is suitable for a spindle with a large load. In August 2004, the company commissioned Shenyang Heavy Machinery Factory to repair the broken shaft of the gyratory crusher. The threaded connection method was adopted, that is, the shaft head that was butted against the broken shaft was first forged, and the material was made of alloy structural steel 30C-2M/V, and then separately The matched internal and external threads are machined at one end of the forged piece and the broken shaft connection, the groove is turned on the butt end face, the thread is connected and then welded, and finally the shaft head is machined according to the drawing on the basis of the broken shaft. This kind of connection method is easy to find, and the neutrality is better. The repaired spindle can be assembled and operated normally. From the situation of using the repaired shaft, the operation effect is good, and the input cost is low, and each repairing spindle is reworked. The price of the product is 251, which greatly reduces the cost.
3.3 Strengthening equipment management First of all, in the daily equipment operation, equipment installation, maintenance, maintenance, maintenance and lubrication procedures must be strictly implemented to accurately grasp the service life of main spare parts. Technicians must know the wear and tear of key components on site, and carefully check the equipment. Record relevant data, use scientific equipment management methods combining theoretical knowledge and practical experience, as far as possible to ensure the coordination of the various components of the equipment, so that the operating conditions are always in the best state; secondly, there are abnormalities such as large ore In the case, we must carefully monitor the operation of the equipment and find that the large ore should take necessary measures to deal with it in time, such as parking the large ore, or the right amount of fire. Third, we must give full play to the subjective initiative of the operators, pay attention to the detailed inspection of the operation process, and do a detailed operation record. When the equipment is parked, the spindle is carefully observed and cracks are found. The welding method can be used as soon as possible to effectively reduce the accident. The incidence rate; the fourth should start with technical improvement, promote and encourage innovation, gradually improve the safety devices of equipment, and ensure the high-quality operation of equipment.
4 Achievements After the occurrence of the main shaft fracture accident of the gyratory crusher in the copper ore smelting ore dressing plant, the relevant technical personnel carried out the accident analysis seriously, and obtained valuable experience and lessons from it, and implemented feasible preventive measures according to the actual situation. At present, the company's concentrating mill gyratory crusher uses the spindle repair parts to absorb the accident lessons. Whether it is the technical improvement of the production process, the reasonable improvement of the spare parts materials, or the strengthening of the basic management of the equipment, the layers have been put in place and achieved remarkable results. Nevertheless, the cooperation of the main shaft of the gyratory crusher and related components, as well as the operation conditions, has yet to be further tested. Many objective factors, such as the large ore of the ore, can only be gradually improved in the future production process to better guarantee the equipment. High quality operation.
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