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Ma Steel's reduced sizing machine gearbox problem Magang high-speed wire rod sizing machine gearbox system includes four gearboxes, each gearbox is equipped with a gear shifting transmission, the clutch device to achieve speed change. The gears are equipped with support bearings. When the clutch is not engaged with the gears, the gears are not subjected to rolling loads and only idle on the shaft. The support bearings only bear the gravity of the gears. When the clutch and the gear are engaged with the gear, the relative rotation between the gear, the bearing and the shaft becomes a rigid connection, and both the gear and the bearing are subjected to the rolling load, and the bearing is subjected to the rolling load without the relative rotation of the inner and outer rings. After using for a month, the bearing rolling elements and the inner and outer ring raceway surfaces are all plastic indented. The bearing damage condition is shown in the figure. Before the transformation, the Maanshan Iron and Steel Transmission gearbox needs to be dismantled and replaced once every six months. The life of the Morgan model gearbox gear support bearing is only half a year. The reason for the damage of the bearing caused by the plastic indentation of the inner ring of the bearing in the transmission gear is that the design is unreasonable, and the force generated by the rolling load is transmitted through the static ball bearing. The balls are in point contact with the inner and outer ring raceways, and the large radial force and the hammering action of the balls cause plastic deformation of the contact points. The impact during rolling caused the plastic deformation zone to expand and develop into bearing failure, gear jumping, and the following technical transformation.
The bearing load test is carried out by taking the D box gear Z= as an example to carry out the load test of the bearing. The deep groove ball bearing acts on the axis, and the tapered roller bearing acts on the axis, and the bearing is stressed. Before and after the transformation, the load analysis of the bearing is analyzed. The load analysis of the deep groove ball bearing before the transformation is carried out, and the load of the tapered roller bearing is analyzed. It can be seen that the static safety factor is doubled after the transformation; the relative rotational speed of the bearing is within the rated speed. The pre-tightened tapered roller bearing of the modified bearing adopts the pre-tightening assembly method to reduce the slip wear phenomenon caused by the rolling body revolution and slip; the rolling specification, the motor speed, and the loose rolling element prevent hammer damage to the inner and outer ring raceways phenomenon.
At the same time, it is necessary to comprehensively consider the temperature difference between the shaft and the bearing housing, the temperature difference between the inner and outer rings of the bearing, the tolerance fit, the elastic deformation of the relevant components, etc., and determine the preload of the bearing by measuring the relationship between the axial load of the bearing and the axial displacement. Axial displacement value GA. The pre-tightening method pre-tightens the positioning pre-tightening method, and the same gauge is rolled after the transformation, and the vibration value is maintained until now. Improper bearing selection. After the gear is completed, the required pre-tightening value is achieved by controlling the difference in the width of the inner and outer ring spacer rings of the two bearings. FAA point bearing inner and outer ring end face spacing measurement value, point bearing inner and outer ring end face spacing measurement value, bearing preload axial displacement value. Place the inner ring of the bearing before installation on the flat surface, apply the measuring load of N on the outer ring, and rotate the bearing several times to ensure that the rolling elements are in full contact with the inner and outer rings, measure the end face spacing with a dial gauge, and evenly measure the points. After taking the average value, it is the F value.
Fig. Bearing end face spacing measurement shows the transformation effect. When the transformation plan was made to the gearbox design and manufacturing department, it immediately received a positive response. The German side offered to freely process spare parts and pre-assemble. The modified D gearbox was put on the line in the year and the year, and achieved good results: the same shafting system was used before the transformation. After the operation month before the transformation, the peephole inspection will find the gear beating, the bearing has plastic indentation, and the running The bearing must be replaced within the month; after the transformation, it has been running for more than a month, and the gears have been checked several times for stable operation. No signs of bearing plasticity have been found. It is expected that the bearing life after the transformation will increase from half a year to more than one year. In view of the successful experience of the D gearbox transformation, the company has officially signed a contract with the German SMS company, and all the other gearboxes have been modified in the same way. It is estimated that after the completion of all the renovations in the year, the annual maintenance and repair time will be reduced, and the spare parts cost will be saved by 10,000 yuan. Through technological transformation, the production process will be improved, the water consumption will be reduced, the water reuse rate will be continuously improved, and the production water will be closed in a closed loop to achieve external drainage. Zero.