Feeder breaker in the operation process often caused by the bearing temperature is too high equipment shutdown phenomenon, in order to solve this problem, our company technicians try a variety of solutions, the effect is not ideal, after the deep analysis of its heating reasons, the bearing box structure reform, to solve the above problems.
1 Device information
Feeder breaker suitable for brittle, medium hard, water content of the material breaking. In building materials and mining enterprises, it is mainly used to break limestone, coal, ore, shale, chalk, gypsum and asbestos ore. Crusher general hammer weight, less hammer, faster speed. There is an upper grid plate, a grate and a feeder breaker with a hammer plate structure, which can enter the material with a larger particle size and should be used as a medium or a certain range of coarse crushing: on the contrary, it is suitable for medium and fine crushing. It has a high crushing ratio (generally 600 to 300), which is its biggest feature. Secondly, its structure is simple, compact, light body weight, easy operation and maintenance. In addition, its product particle size is small and uniform, and too little crushing. Feeder breaker crusher driven by motor, coupling connected short shaft assembly, short shaft assembly through the pulley drive crusher work, motor power 900kw, model yrkk560-6, speed is 980r/min. The bearing model at both ends of the short shaft assembly is 23232c3 self-aligning roller bearing. In the operation process, the bearing temperature on both sides of the small pulley is too high to control, the bearing seat at both ends continues to be high temperature, and the temperature after cooling by the fan in winter often exceeds the breaker shutdown alarm value of 80℃. The high temperature often causes the crusher to stop, which affects the crusher output and operation rate.
(1) The tension of the v-belt is adjusted: (2) the two bearing seats are aligned: (3) the motor coupling is aligned: (4) the flatness of the two belt wheels is adjusted. The operating temperature has no obvious change after adjustment.
2 Cause analysis
Through the disintegration check of feeder breaker, it is confirmed that the high temperature of the bearing box is mainly caused by the heat caused by the bearing during high-speed operation, rather than the heat caused by the friction of other parts. During the operation of the bearing, due to the rolling friction between the rolling element and the inner and outer rings, the temperature rise is inevitable, but because the bearing seat is exposed to the air, it has a certain heat dissipation effect. The final temperature will be stable at a certain value, then the bearing temperature continues to rise about two factors, one is the production: the heat generated is too large: the second is the heat dissipation effect is not good. From the structure of the bearing box, the main reason is that the heat generated by the bearing is too large. There are two main reasons for excessive heat: (1) the effect of speed on bearing heating. The speed of each kind of rolling bearing has a certain limit, and the temperature rise generated by the internal friction of the bearing will also increase when the bearing load p exceeds the basic rated dynamic load by 8%. Or under the condition that the axial load f exceeds the radial load f20%, it is necessary to multiply the bearing limit speed with a certain correction factor to correct the limit speed. When the bearing speed exceeds the limit speed, the bearing accuracy, (internal) clearance, cage structure, materials, lubrication and other conditions should be improved, otherwise other problems such as heating may occur.
The greater the frictional dynamic torque of the bearing, the greater the heat. The friction coefficient of the aligning roller is larger than that of other bearings.
The short shaft assembly is directly connected to the motor, and the speed is the same as the motor speed, 980rmin, while the self-aligning roller bearing 23232 has a limit speed of 1000rmin. It can be seen that the working speed is basically close to the limit speed, if the bearing friction coefficient and the limit speed correction factor are considered, the working speed has exceeded the allowable limit speed of the bearing, which is one of the main reasons for the bearing heat. In addition, the two aligning roller bearings of the short shaft assembly, one of which needs to be the floating end and the other is the fixed end, the bearing and the bearing seat use a clearance match to ensure the floating of the bearing, but the bearing seat hole may be used for a period of time to varying degrees of shape and position tolerance, resulting in the floating end of the bearing is not smooth, the bearing axial load is too large, and it is also one of the reasons for the bearing heat.
Keep using the original bearing seat, as there is a certain difference in the width of the bearing, during installation, measure the width difference and machining the outer spacer with the outer diameter size to ensure the axial compression of the bearing. In addition, due to the weak aligning performance of the deep groove ball and cylindrical roller bearings, the centering requirements of the two bearing seats are higher, and the laser is used to adjust the centering instrument during installation to ensure the concentricity of the two bearing seats.
