Failure analysis of bucket teeth of excavator

During the operation of the electric shovel, the bucket is the main working part. In the mining process, the bucket, under the action of the push shaft, goes deep into the interior of the mining materials and makes constant collision and friction with the internal materials. In this process, the bucket teeth of the excavator, as the main cutting parts, need to bear the action of severe impact resistance and bending moment. Under the joint action of these forces and moments, the bucket teeth of the excavator are prone to failure. According to the failure form of excavator bucket teeth, it can be divided into wear, fracture and falling off.

(1) Bucket teeth of excavator are worn

According to the requirements of the working environment of the excavator, the top part of the bucket tooth of the excavator should have good wear resistance, and the tooth seat part should have sufficient strength and toughness. However, because the bucket tooth of the integral excavator is made by one-time casting, and considering the casting cost of the bucket tooth of the excavator, the performance of the two parts can not be considered generally. When the yield strength of the bucket teeth of the excavator is relatively low and the bucket teeth of the excavator are cutting under the action of high impact load, the bucket teeth of the excavator will produce plastic deformation and then form plastic furrows. On the one hand, it will make the surface of the bucket teeth of the excavator rough and increase the friction force during the movement of the bucket teeth of the excavator; On the other hand, the plastic furrow will increase the brittleness of the bucket tooth surface of the excavator. If it is impacted by rocks and other materials at this time, the surface of the bucket tooth of the excavator is easy to produce brittle cracks and accelerate the failure of the bucket tooth. If the bucket tooth of the excavator is inserted into the ore, the protruding part in the furrow formed on the surface of the bucket tooth of the excavator will be rolled by the material for many times when the bucket tooth of the excavator is continuously inserted and removed from the material. When the stress exceeds its strength limit, debris will also be generated to accelerate the wear of the bucket tooth of the excavator. Moreover, when the bucket teeth of the excavator are inserted into the ore and move, the surface of the bucket teeth of the excavator will be invaded by ore particles and produce long strip chips. Under the action of this series, the bucket teeth of the excavator will gradually become thinner and shorter, which will lead to the failure of the bucket teeth of the excavator.

(2) Bucket teeth of excavator are broken

When the impact load is too large, or hard ore or frozen layer is encountered during excavation, the bucket teeth of the excavator will bear a great impact load. If the toughness of the bucket teeth of the excavator is low, it will break under the action of impact load. Since the junction of the bucket tooth tip and the tooth seat of the excavator presents a hollow structure, a certain stress concentration will be generated under the action of external force. This is the key position of the bucket tooth fracture of the excavator. In addition, in the process of excavation, the stress on the upper and lower sides of the excavator bucket teeth is uneven, resulting in serious wear on one side. When the excavator bucket teeth separate materials, they will bear the action of bending moment. At this time, the excavator bucket teeth are also prone to fracture failure.

(3) Bucket teeth of excavator fall off

The falling off of bucket teeth of excavator means that the whole bucket teeth of excavator fall off from the tooth seat. The bucket teeth of excavator are connected with the bucket lip by C-type chuck and wedge. Under the action of impact load and fatigue stress, the connection is easy to become loose, so the lock pin may be broken. When the lock pin is broken, the wedge will loose and fall near, which will directly lead to the falling off of the bucket teeth of the excavator.

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