Radial Truck,Bus Tires,Cooper Samson,China Westlake Car Lift,Field Tire Co., Ltd. , http://www.nbbustire.com
1 Introduction Thermal power plant 1 electric fan is manufactured by Shaanxi Blower Factory in 1998. The fan model is D1200, the fan shaft is equipped with thrust bearing (7 watt), and the speed increasing box model is GYD350 high-speed arc cylindrical gear transmission. A thrust disc is arranged at both ends of the gear, and a thrust bearing (3 watts) is arranged on the large gear. The motor model is YKOS3600-2, and the structure is installed and put into operation in 1999. Since October 2002, the vertical gear of the gearbox (6 watts) of the gearbox has a large vertical vibration and has a deteriorating trend. It has been specially protected. By November 28, 2003, the vertical vibration of the tile reached 13mm/s. And the meshing sound of the gear pair is not good, the wind pressure is increased, the vibration does not drop much, and the operation cannot be continued, and the maintenance is decided.
2 Increase gearbox gear and bearing replacement data In view of the above situation, the machine was stopped and found to have a large wear on the gears, and some of the bearing bushes also had some wear, so it was decided to replace the gear pair and the gearbox bush. After the gear pair and the speed increase box bush are replaced, all the installation parameters are adjusted within the specified range, the gear watt parameters, the motor and the speed increase box, and the center value of the speed increase box and the fan.
3 Problems existed After the installation and acceptance was completed, the test was started at 9:00 on December 5, 2003. When the machine was turned on, the vibration of each fan was not large, and the load was gradually increased to 100 kPa. The vibration of each tile was relatively small, and the test operation continued. At 13:00, the vibration of each tile still changed little, so the wind was supplied to the blast furnace, and the load was gradually increased. When the load was added to 150 kPa, the time was around 23:00, and the 7-watt axial and vertical vibration suddenly increased and decreased. The load, axial and vertical vibrations are still large, and then stopped at around 2:00 on December 6th. Since the vibration suddenly changed to 7 watts, the other tiles did not change much, so only 4, 5, 6, and 7, Eight watts of vibration data are listed for analysis.
4 Analysis and treatment 4.1 Analysis and treatment from the fan and fan and speed-increasing center As the vibration is expressed on the fan bush (7 watts), the factors related to the fan and vibration and the speed-increasing box are emphasized in the analysis and processing of the problem. The gear shaft is centered on the rotor of the fan. For each analysis, all the things that can be thought of are processed. After the test, the machine is tested. The result is 13 times, but the situation of each test machine is similar. After starting or starting for a period of time, the 7-watt shaft The vertical and vertical vibrations are large, delaying a lot of time, wasting a lot of energy, and also affecting production. Through the online detection system, it is known that the excitation force causing the vibration is the power frequency and the double frequency, and the double frequency is relatively large, which is about 80 of the power frequency, and the excitation force of the vertical vibration is the power frequency.
4.2 Analysis and processing from the speed-increasing gear pair After analyzing and processing the central aspects of the fan and fan and the speed-increasing box, the problem still remains unresolved, so it is decided to focus on the analysis and processing on the gearbox gear pair. .
4.2.1 Comprehensive inspection of the gear pair Through the comprehensive inspection of the gear pair, the force analysis on the indexing circle of the 4.2.2 helical gear transmission is different because the helical gear transmission and the spur gear transmission generate an axial direction in the transmission. Force, force analysis of the indexing circle of the helical gear transmission. When the friction of the tooth surface is omitted, the normal force acting on the pinion gear in the normal meshing plane perpendicular to the tooth surface is: FnFtcosαncosβ normal force It can be decomposed into the working circular force Ft: Ft2000Td12×107P2лnd(N) The axial force is: FaFttgβ(N)cm/s564.2.3 Cause Analysis When the gear pair is working, the axial force is generated on the large gear and the pinion, it is Balanced by the thrust faces of both sides of the large gear and the pinion thrust disk with a 2° cone angle. For the pinion, the axial force it receives is away from the fan. This axial force is balanced by the large gear through the thrust plate 1 to give the pinion an axial force directed in the direction of the fan. A prerequisite for the transmission of the axial force of the thrust disc is that the thrust disc should have a hydrodynamic action, i.e., a dynamic pressure oil film is formed to create a liquid friction between the two opposing moving surfaces. The necessary and sufficient conditions for the formation of liquid friction between the two surfaces are (a) viscous liquid, (b) relative motion, and (c) convergent geometry. Since the scoop of the thrust disc 1 is 0.1325 mm, which is seriously exceeded, the thrust disc 1 loses the axial force, so that it can not work as required, and it generates an axial exciting force when rotating, thereby causing the shaft. To the vibration, due to the structural characteristics of the gearbox gear, that is, the setting direction of the thrust bearing on the large gear, its axial exciting force is only reflected by 7 watts (fan bush with thrust bush). It can be seen from the scoring of the thrust plate 1 that the frequency of the axial excitation force is mainly the power frequency, and the second frequency is less, which is in line with the vibration induced vibration seen on the vibration spectrum diagram of the online detection system. The force is the power frequency and the double frequency.
4.2.4 After the analysis, the pinion gear was sent to the Shaanxi Blower Factory for re-processing of the thrust plate 1. The re-machined thrust plate 1 was biased at 0.02 mm (required), and was returned to the factory for installation and start-up. Trial operation, air supply to the blast furnace, vibration is normal.
5 Conclusion In the analysis and processing of the vibration of the fan bushing, due to the lack of experience, we spent a lot of time and energy on the fan and the center. As a result, the problem has not been solved. Later, the vibration of the fan bush was discovered. Due to the cause of the gearbox of the speed-increasing gearbox, it is necessary to comprehensively analyze the vibration analysis of the equipment, and it cannot be confused by the surface phenomenon.