Treatment method of broken shaft of drive reducer

When the drive reducer of belt conveyor is used, the input shaft of some drive reducers is often broken, which has a certain impact on the production of users. When the shaft is broken, only the input shaft is usually broken, while the output shaft is rarely broken. In severe cases, the input shaft will be broken successively on several belt conveyors. This situation will occur when all reducers with broken shaft are the same supplier of belt conveyor. When the shaft is broken, the stubble at the fracture of the rear shaft is generally flush, and the section is generally perpendicular to the length direction of the shaft. Shaft breakage occurs on both the belt conveyor on mobile machinery and the ground belt conveyor.
1. The external main causes of shaft failure shall include the following aspects:
1.1 the bearing capacity of the reducer of the selected belt conveyor is not enough, that is, the driving reducer of the belt conveyor is too small. When the actual power of the reducer exceeds the bearing capacity of the reducer, the shaft of the belt conveyor driving reducer will be broken within a certain time;
1.2 the hydraulic coupling and brake wheel are usually installed between the motor shaft and the reducer shaft. When the dynamic balance of the brake wheel and hydraulic coupling is poor and the eccentricity is serious, it will cause great vibration during the operation of the belt conveyor. When the vibration load reaches a certain degree, the stress on the output shaft of the reducer is too large and breaks;
1.3 the concentricity deviation of installation is too large. If the hydraulic coupling and brake wheel between the motor and the reducer are installed, the concentricity between the reducer and the motor shaft shall be carefully adjusted. If the deviation is too large, the coupling and brake wheel will produce too much vibration during operation and break the shaft.
1.4 the input shaft is broken due to the defect of reducer design. This situation occurs when the belt conveyor is designed and the reducer is selected in full accordance with the requirements of the reducer supplier. Although the selected reducer met the requirements of the reducer supplier, the shaft was still broken.
2. The internal factors of reducer shaft breaking mainly include the following aspects:
2.1 excessive stress at shaft fracture during reducer design;
2.2 the curvature radius and change curve of the transition fillet are not carefully considered at the shaft shoulder at the input shaft of the reducer, resulting in serious stress concentration and fatigue failure;
2.3 the reducer is in the form of vertical shaft, and the primary input shaft is bevel gear shaft. Serious stress concentration occurs at the transition shaft shoulder at the bevel gear support bearing and fatigue failure occurs;
2.4 the reducer is a hard tooth surface reducer, and the diameter of the input shaft of the reducer is relatively small. Although the strength is calculated, the shaft itself is very thin, so the stress concentration is serious and fatigue failure occurs at the change of shaft diameter;
2.5 the heat treatment quality of input shaft is unqualified;
2.6 improper material selection of input shaft.
3 methods and measures to avoid and reduce shaft breakage of reducer shaft
3.1 modify the design of reducer;
3.2 during installation and maintenance, pay attention to adjusting the concentricity of motor and reducer to meet the conventional requirements;
3.3 when the reducer with parallel shaft can be used, it is better not to use the reducer with vertical shaft;
3.4 when selecting the reducer, consider or calculate the allowable radial load of the reducer;
3.5 when selecting the motor speed, six pole motor shall be selected as far as possible, that is, the motor with synchronous speed of 1000 R / min shall be used as the driving motor, so as to reduce the vibration of coupling and brake wheel during high-speed rotation, especially for belt conveyor with large power, such as belt conveyor with power greater than 90kw, it is better to select low-speed motor, At this time, the price of the motor will be correspondingly higher than that of the four pole motor;
3.6 try to reduce or control the unbalanced torque of hydraulic coupling and brake wheel.
Through the above methods, the problem of shaft breaking of the input shaft of the drive reducer of the belt conveyor can be basically found or solved. In the belt conveyor system with frequent operation, necessary spare parts of reducer shall be properly equipped for timely replacement to avoid affecting normal production.