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Why Does The Gearboxes Have Occured Broken Shaft?
Sep 01, 2018

When the concentricity between the drive motor and the decelerator is well guaranteed, the output shaft of the drive motor bears only rotational force (torque), and runs smoothly without pulsation. In the case of different centers, the output shaft of the drive motor also bears the radial force (bending moment) from the input of the reducer. This radial force will force the output shaft of the drive motor to bend, and the direction of bending will change with the rotation of the output shaft. If the concentricity error is large, the radial force will cause the local temperature of the motor output shaft to rise, and the metal structure will be destroyed continuously, which will eventually lead to the drive motor output shaft broken due to local fatigue. The larger the error of concentricity is, the shorter the time of breaking off the output shaft of the driving motor. When the output shaft of the drive motor is broken, the input side of the reducer will also bear the radial force from the output shaft of the drive motor. If the radial force exceeds the maximum radial load that the input side of the reducer can bear, the result will also lead to deformation or even fracture of the input side of the reducer or support of the input side. The bearing is damaged. Therefore, it is very important to ensure concentricity during assembly. From the assembly process analysis, if the drive motor shaft and reducer input concentric, then the drive motor shaft and reducer input face will be very close to each other, their contact surface closely, no radial force and deformation space. If the assembly is not concentric, then the contact surfaces will not fit or have clearances, there is a radial force and provides space for deformation.


Detailed Reasons as below:

1. The design of the high speed shaft of the reducer is not strong enough.

This usually happens at the shoulder of the shaft, and because there is a transition fillet, it is very easy to fatigue damage, such as too small fillet will make the reducer in a shorter period of time off the shaft. After fracture, the fracture is usually flat. In this case, the reducer should be replaced or the design of the reducer should be modified.

2. High speed shaft is not concentric.

When the motor shaft is not aligned with the high-speed shaft of the reducer, the input shaft of the reducer will increase the radial load and the bending moment of the shaft, and the shaft will be broken in long-term operation. When installing and servicing, the position should be carefully adjusted to ensure concentricity of two axes. In most cases, the motor shaft will not break, because the material of the motor shaft is generally 45 steel, the motor shaft is thicker, stress concentration is better, so the motor shaft usually does not break.

3. Broken shaft under double motor driving

Dual motor drive is equipped with two speed reducer and two motors on the same driving drum. It is easy to break the shaft when the design or the allowance of the high speed shaft of the reducer is small. In the past, the belt conveyor did not use hydraulic coupling to drive this kind of situation more easily, because the two motors in the start-up and operation of speed synchronization and force balance is difficult to ensure. At present, most of the hydraulic coupling shaft breakage phenomenon has been used less, but the use of the coupling should not be too much fuel, in order to make it have limited torque and improve the service life of the coupling.

4. There is too much impurity in the reducer.

There will be a lot of impurities in the reducer, some impurities if it is granular impurities will cause the formation of the point stone of the gear, but how the particles of impurities is very large will easily cause serious internal damage of the reducer, serious time will also cause shaft breakage of the reducer. The gear box cleaner uses the original oil supply and drainage system of the gearbox and filtered lubricant to clean the gearbox without changing any hardware facilities or adding any cleaning agent, thus ensuring the safe operation of the gearbox and prolonging the service life of the gearbox. The reduction of the shaft breaking condition of the reducer is reduced.

    Similarly, the output shaft of the reducer also breaks or bends, and the reason is the same as that of the drive motor. But the output of the reducer is the product of the output of the driving motor and the reduction ratio. Compared with the motor, the output force is greater, so the output shaft of the reducer is easier to be broken. Therefore, when using the reducer, the user should pay more attention to the guarantee of concentricity when assembling the output of the reducer.

       *For more detailed parameters,size,price.Pls contact the Hangzhou Starred-River Machinery Co., Ltd.




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