BLOGS > Reasons and preventive measures of main shaft fracture of jaw crusher and impact crusher

Reasons and preventive measures of main shaft fracture of jaw crusher and impact crusher


The fracture of the main shaft is a very serious fault for crusher, because once the main shaft is broken, the maintenance will take a long time and high costs, which will bring great economic losses to the enterprise.

Here are the reasons and preventive measures of main shaft fracture of jaw crusher and impact crusher.

Primary jaw crusher
impact crusher

Reasons of main shaft fracture of jaw crusher

1. The performance of the jaw crusher itself

The better the production performance, the more durable the device will be. When manufacturing the main shaft, if the heat treatment work is not done well, the fatigue resistance of the main shaft will be reduced. Once it crushes materials with high hardness or cannot be crushed, resistance will occur, which will increase the burden on the main shaft and make the main shaft prone to cracks, leading to main shaft fracture.

2. Improper speed control

Improper speed control of the jaw crusher will accelerate the wear of the body. For example, when the load changes, the corresponding diesel engine speed will also fluctuates. If the speed change rate is too large at the same time, the idling speed will also be relatively high, it will affect the stability of the jaw crusher engine work, accelerate the body wear; if the speed change rate is too small at the same time, and it will also cause the instability of the engine operation.

3. Improper operation

In the production process, improper operation such as suddenly increase the feeding volume or change other properties of the material will cause the machine to be temporarily out of control, resulting in the phenomenon of sudden fast and slow, so that the jaw crusher becomes unstable under high-speed operation, which accelerates the wear of the main shaft.

4. Incorrect structural arrangement

The main reason is that the structural design of the main shaft is unreasonable, and it is easy to generate stress concentration, which is manifested in the large interference of the mating surface of the main shaft and the movable jaw, the filter fillet is too small and there is no unloading groove, which is easy to cause long-term overload of the equipment. When running, the main shaft will fatigue and speed up the wear, and for those main shafts with smaller widths, it is more likely to fracture.

Reasons of main shaft fracture of impact crusher

1. Unqualified performance of the main shaft

1) Although the main shaft of impact crusher bears a large load, if the main shaft fractures within a short period of use, it means that the performance of the main shaft itself is unqualified. The production materials of main shaft are usually carbon steel and alloy steel, and the existence of non-inclusions in steel is easy to cause stress concentration, and the edge of these inclusions is easy to form cracks, resulting in the fracture of main shaft in a short time.

2) If the main shaft is put into use without heat treatment, it will reduce the anti-fatigue performance of the main shaft. It is easy to appear stress concentration in production, and it will gradually crack the surface of the main shaft. When confronted with sudden problems, it may cause the fracture of the main shaft.

2. Improper production operation

1) The friction force of the bulk material on the main shaft is very large, and the shear stress position tends to the surface, which easily causes the main shaft to crack. On the other hand, if the feeding particle size of the crusher is too large, or the processing raw materials with a lot of water adhere to the inner wall, it will cause internal blockage and cause damage to the main shaft.

2) During the feeding process of impact crusher, if there are objects that cannot be crushed enter the crusher, it will impact the main shaft and other parts, especially when there is iron in the machine, which will cause resistance to the main shaft and cause serious wear and tear or even fracture of the main shaft.

3) If the crusher is overloaded for a long time, the main shaft will be impacted by the machine for a long time, which will cause the fracture of the main shaft in the long run.

3. The lubrication effect is not good

The main shaft is the main lubricating part of impact crusher. Improper lubrication will greatly reduce the service life of the main shaft. On the other hand, if the lubricating oil contains moisture, the thickness of the oil film will be reduced, which will accelerate the expansion of the main shaft crack and cause the main shaft to fracture.

Preventive measures of main shaft fracture

To reduce the chance of fracture of the crusher main shaft, the following preventive measures can be taken:

1. For the operators of scrapers, ground loaders and transporters, it is necessary to improve their awareness of equipment maintenance, ensure the integrity of the bucket, gear, transport belt and the hinged pin shaft, and ensure that it will not produce metal impurities and enter the crusher. At the same time, the maintenance and replacement for some large wear gear and its surrounding parts should be carried out timely.

2. The operator needs to lubricate the equipment according to the requirements. During the operation, it is necessary to check whether the lubrication of the equipment is good under the premise of safety, and to observe the operating load of the equipment at all times. Observe whether the equipment has oil pressure, oil temperature and abnormal noise during operation.

3. Supervisors should be vigilant, pay close attention to the operation of the equipment, and clean up foreign objects that enter the machine in time to ensure that the equipment is in good operating condition.

4. When repairing the crusher, reasonably recycle the damaged parts of the equipment. It is strictly forbidden to randomly discard all kinds of metal materials into the ore. At the same time, some equipment that is close to being scrapped or at the edge of scrapping needs to be replaced directly.

5. In daily operation, pay attention to feeding volume of material at all times to avoid the phenomenon of excessive feeding, which may cause the possibility of main shaft fracture.

6. Regularly use ultrasonic and other instruments to detect the stress of the main shaft, understand the degree of stress of the main shaft, and timely repair and replace the worn parts.

7. For the main shaft, the main body of the crusher and other important parts, it is necessary to do a good job of inventory backup, so as not to cause the entire production system to stop production after special circumstances, thus affecting the overall production.

8. Strengthen the professional skills training of operators in all aspects, improve their practical operation ability as much as possible, improve the maintenance effect of equipment, and carry out major and medium repairs on equipment in time to ensure that the equipment is in good working condition for a long time.

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