1. Material issues
The material of flywheel and pulley is generally gray cast iron, because of its low cost and easy processing. But the shortcomings of gray cast iron are brittleness, poor mechanical properties, and cracks easily caused by external forces.
2. Operating conditions
Affected by the mining technology, the ore blocks entering the crusher are relatively large, and it is prone to cracking of the jaws or stuffiness of the ore draw machine. Sometimes it has to be treated with explosives, which will inevitably have an impact on the crusher and even the flywheel. Cracks will appear.
3. Design and manufacturing process issues
The crack is at the transition of the casting fillet, the wall thickness difference is large, the transition fillet is small, stress concentration is prone to occur after pouring, and cracks are prone to appear after loading. The casting fillet is not suitable for selection, which will cause shrinkage and cracks during pouring, resulting in stress concentration. All of the above problems will gradually show up due to stress problems during operation and cracks will appear.
1. In order to avoid processing stress on the outer circle of the flywheel hub, a certain chamfer should be retained during processing to ensure the surface processing accuracy and processing size.
2. The two sides of the flywheel spoke are processed to ensure sufficient contact area between the splint and the spoke. The processed surface and the unprocessed surface of the spoke are chamfered to transition.
3. Machining a pair of flanges with bosses, using No. 45 steel with good plasticity, toughness and easy processing.
4. The inner hole size and tolerance of the flange sleeve is a transitional fit with the outer circle of the processed hub, which is convenient for clamping the flywheel with cracks.
5. Use reamed holes and high-strength bolts to fix.
6. Install the processed pair of flange sleeves on both sides of the flywheel to ensure the installation is in place.
7. Use a reamer to evenly ream a certain number of bolt holes, and use high-strength bolts to fix the flange and the flywheel spoke to ensure the clamping strength of the two flanges to the flywheel spoke.
8. Regular inspections to prevent further cracks and deformation of the flywheel.
The above treatment measures have good effects and can meet the requirements of normal production and operation. Due to the harsh working environment and medium conditions of the jaw crusher, some problems will inevitably occur during use. Flywheel cracks are often treated by welding repair methods, although its cannot be fully restored, but production can be resumed in a short time. However, if the crack reappears, it will be discarded, which is also what users need to pay attention to.