Because the broken stones are of high hardness and large particle size, the jaw crusher has high working strength and bad working environment. In the case of long-term use, stone on the crusher components caused by wear is very large, and even can reduce the service life of jaw crusher, and will inevitably fail. How to take effective and fast maintenance methods to repair the fault and reduce the downtime is very important for production enterprises.
01 Foundation treatment
Jaw crusher is used in the raw materials with strong hardness and large crushing. It is normal to have strong vibration in the work, and the reinforced concrete structure is stable. If cracks and loose signs appear after operation, timely adjustment should be made to avoid adverse effects on safe operation. In a construction site, due to the influence of earthquake, the foundation sank, and the downstream side of jaw crusher frame sank 35mm more than the upstream side. During the operation of jaw crusher, the body tilted down to the downstream side, and finally the moving jaw frame was worn down to the downstream side, and the upstream side of the main shaft was seriously worn, and the inner and outer bearings were damaged. It is necessary to deal with the sinking frame in time to ensure the normal production of jaw crusher.
First, loosen all the anchor bolts on both sides of the frame, then use two 50t jacks to jack up about 40mm on both sides of the frame on the downstream side, chisel the bottom of the side, and then pad the cut 30mm steel plate into the lower part according to the distance between the bolts. Finally, use high-grade concrete mortar for plastering and ensure that the bolts are tightened after 48 hours of hardening, Resume production.
02 Replace feeder base plate
Long time impact and stone wear caused a large cavity in the feeding base plate of jaw crusher, which could not be repaired. After manual cutting, it was found that the original wear-resistant manganese steel plate with a thickness of 20 mm had been worn like a sheet of iron full of cavities. In this way, the material leakage at the bottom is more serious, which greatly increases the labor of slag cleaning workers, and the stone splashing from the bottom increases the risk of insecurity. It must be replaced to ensure safe production.
First, measure the width and length of the bottom plate, cut off 3-5 pieces of 20 mm thick manganese steel (to prevent one piece from being too heavy to be lifted to the designated position mechanically and manually), and clean up the residue at the bottom plate (to ensure firm welding). Then, professional welders fix and weld each steel plate, and use angle grinder to level the welding thickness between steel plates, After welding, weld inspection shall be carried out to prevent local wear of steel plate caused by welding defects. After repair welding, re install and resume production.
03 Anchor bolt fracture repair
Because there are a lot of stones in the crushing cavity of the jaw crusher made of oversized stones, the crusher stops. When the crusher is restarted, the anchor bolts bear a large shear force, which causes the bolts to break under shear stress; Or jaw crusher is subject to load vibration, unstable foundation, bearing damage, bolt looseness caused by eccentric load increase, the whole crushing frame swings, in addition, the maintenance and inspection is not timely, the equipment works with “disease” for a long time and is not found in time, which eventually leads to bolt fracture.
If there are many broken anchor bolts, cracks in the foundation, and there are many hidden dangers in the continued use, the machine must be shut down immediately. The original concrete foundation is removed, the anchor bolts are replaced and the foundation is poured again. Remove the bolt concrete foundation of the original footing, take out all the bolts, and clean up the working face on site; After alignment, replace all foundation bolts; The foundation grouting of anchor bolts shall be carried out. After the concrete reaches the strength, the machine shall be installed, the anchor bolts shall be tightened, and the next process shall be carried out after rechecking; When anchor type movable anchor bolts are used, appropriate reserved pipes shall be embedded. Fine aggregate concrete is generally used for grouting.
04 Spindle repair
As mentioned above, the long-time foundation subsidence caused serious wear of the main shaft on the upstream side. After removing the bearing on this side and lifting the jaw body, the measurement found that the shaft diameter on this side was 6-12mm smaller than that on the downstream side (because of uneven wear, the shaft diameter was out of normal circle). As a result, the bearing was replaced many times and the fault could not be eliminated. The spindle needs to be treated.
The outer circle surfacing method is adopted, and the manual arc welding is used to evenly overlay a layer on the worn bearing joint surface. The surfacing method of “small current, small weld bead and discontinuous” should be adopted, that is, to weld a certain length of weld bead. In the red state of weld bead, the hammer is used to quickly hit the weld bead, so as to reduce the shrinkage stress, water with welding, and quickly cool, so as to improve the wear resistance. Then according to the requirements of fit tolerance, reaming processing is carried out again to achieve the purpose of reasonable fit with the outer diameter of bearing. In this way, the welding layer of the shaft is thin, so there is no deformation during surfacing, and there is no special requirement for the welding process. However, the perpendicularity between the shaft center line and the two end faces should be well controlled when machining the shaft, so as to ensure the matching relationship and precision with other parts.
In case of emergency maintenance on site, skilled welders can be selected to weld 24 vertical seams evenly on the bearing. After polishing, the height is 5mm higher than the original shaft. Then, touch some white dust on the 24 vertical seams to insert the bearing inner sleeve. Where there is no white dust mark on the bearing inner sleeve, the bearing inner sleeve can be polished again until it is in good condition with the inner sleeve (to ensure that the shaft is round), and then it can be assembled and used.
05 Replacement and lubrication of inner and outer bearing of movable jaw
During the operation of jaw crusher, there is a harsh noise, and the jaw crusher is stuck in a short time, and the flywheel no longer rotates. When the flywheel was disassembled and the cover was opened, it was found that the outer bearing cage of the movable jaw was damaged, and the inner rolling ball was scattered and damaged; After lifting the movable jaw, it was found that part of the inner bearing was damaged.
First, deal with the movable jaw inner bearing: Boil the spare parts bearing in stock for 2 hours, use the big hammer pad copper rod, and many people hammer in turn to wedge the bearing into the original position. After that, the moving jaw is hoisted as a whole. For the external bearing, the self-made steel pipe pad can be used to lift the main shaft, the small crane can be used to lift the bearing onto the shaft, and then hammer into the designated position according to the steps. Then lift the flywheel, install the V-belt, and start the machine after debugging. The grease used for jaw crusher should be determined according to the place of use and air temperature. Generally, calcium base, sodium base and calcium sodium base grease are used. The grease added into the bearing seat is about 50% of its space volume, and it should be replaced every 3-6 months. When changing oil, clean gasoline or kerosene should be used to clean the raceway of roller bearing.