Mineral sizers is the main crushing equipment in the coal preparation industry, and is also widely used in solid waste treatment, construction waste separation and other fields. It has the characteristics of directly passing the material with the particle size meeting the requirements and forcing the crushing of large materials, which can achieve the dual purpose of crushing and screening of materials at the same time. Common large mineral sizers are generally driven by double motors, and the power and transmission components of the two working tooth rollers do not interfere with each other and work independently. In the actual production process, when mineral sizers driven by two motors work under continuously changing conditions of high torque, the speed of the two tooth rollers will fluctuate, resulting in unstable loading of the tooth tip of the tooth roller on the material, and there may be "Yield" And "Slip" And other phenomena when the material is gripped. Thus resulting in the crushing process of material blockage, discharge particle size is too large, the increase of fine particles, affect the crushing effect and production efficiency.
1.The main structure of mineral sizers is shown in figure 1. The two motors provide input power, and the reducer converts the input high speed into a lower speed, and finally makes the crushing tooth roller break the material with the characteristics of low speed and high torque. The hydraulic coupler is connected between the motor and the reducer, which can play the role of smooth start of the crusher, overload protection, vibration isolation and so on. There are two reasons that affect the speed fluctuation of mineral sizers, on the one hand, the influence of the characteristics of its structural components and on the other hand, the influence of working loads.
Influence of mechanical component characteristics In the power and transmission structure of mineral sizers, the reducer and the shaft are rigidly connected, and the output speed of the motor and the hydraulic coupler changes with the change of the torque.
2.Mineral sizers forced synchronous design and speed test in common mechanical transmission methods, gear transmission has the characteristics of high transmission ratio accuracy, high efficiency, and stable transmission. In order to improve the stability and synchronization of the gear roller speed, the synchronous gear can be applied to the mineral sizers machine to force the speed synchronization. Based on this assumption, the synchronous gear mechanism of a certain type of mineral sizers in an industrial site was reformed. The mineral sizers with synchronous gear were tested in the field for industrial application. It was found that the crushing effect of materials was significantly improved and the broken products were more in line with the expected requirements.
From the above analysis, it can be seen that the speed stability and synchronization of the synchronous gear are obviously optimized after it is applied to the mineral sizers. In order to explore the motion law of gear mechanism under synchronous state, high-speed photography technology can be used to photograph and analyze the working process of synchronous gear. High-speed photography technology is an extension of human visual ability in time resolution, which can meet the needs of image recording and analysis of fast moving objects. The image shooting speed is set to 1400 frames per second according to the speed of the gear roller. When mineral sizers come into operation, a high-speed camera is used to photograph the synchro-gear bite site and preserve the results. The captured gear mesh image was decomposed and analyzed. Punctuate the tooth tips of the left and right gears respectively to make the image move 50 frames, while tracking the position of the mark points in different frames of photos. According to the moving distance of the point and the time interval of each frame image shooting, the instantaneous linear velocity of the marked point movement at different moments in a period of time can be calculated. The decomposition motion state of two gears in a period of time can be analyzed by comparing the instantaneous linear velocity of the tooth tip of the gear.
The instantaneous linear velocity of tooth tip motion of the two gears and the change of linear velocity difference with the number of time frames are respectively drawn into images, as shown in fig. It can be seen from the analysis that in the actual work, the instantaneous linear speed of the tooth tips of the two gears always has a small speed difference, and alternately leads, and then becomes equal speed, and the overall is irregular periodic change. This shows that when the speed of a gear has a tendency to change faster or slower, the other gear will give it resistance drag, weakening the trend of its speed change. Through the stable bite of synchronous gears, continuous mutual restraint, the fluctuation of gear roller speed is reduced, and the synchronization is enhanced.