We have analyzed more than 50 mineral sizers in domestic coal mines in recent years and found problems, although these crushers have achieved significant economic benefits. Crusher teeth are the main working parts of the crusher, but also the main wearing parts, its life length and work efficiency not only directly affect the life and efficiency of the crusher, but also closely related to the crushing power consumption, production capacity and the quality of the discharge particle size. According to the different types of crushing materials, the material, shape, fastening method and tooth height parameters of crushing teeth are different. The service life of the crushing teeth mainly depends on the structure, material and fastening method of the teeth. Taking mineral sizers as the research object, the structural forms of mineral sizers fracture teeth are compared and combined with the actual operation of the field, which provides a theoretical basis for the design of mineral sizers fracture teeth. The crown and the ring seat are bolted together, and the crown is covered by a wear-resistant shell welded from wear-resistant steel plates.
According to the damage of crushing roll teeth in mineral sizers, the crushing roll teeth are broken, and there are materials sticking on the joint surface of crushing roll teeth and tooth base. The reasons are as follows: First, the fastening mode of the crushing tooth structure is unreasonable and there are contradictions, which makes the stress state of the crown of the tooth and the clamping state of the bolt bad, resulting in a bad stress state, and easy to break when subjected to a large impact or difficult to break materials; Second, there are defects in the manufacturing of crushing roll teeth, which lead to the accurate joint of crushing roll teeth and tooth base, and the stress state of crushing roll teeth is not good. The reasons for the contradictions in the structural fastening methods of mineral sizers crushing teeth are analyzed as follows: When the bolt is not closed, due to the need of assembly, the two sides of the tooth ring seat and the tooth crown are interstitially matched, and when the bolt is tightened through the tooth crown and the tooth ring seat, after the bolt is closed through the bolt hole, the retightening force of the bolt only acts on the tooth crown of a single part, that is, the two outer cutting faces of the tooth crown of the portal structure. Due to the large crushing force, the tooth crown is a door-shaped structure with great strength and stiffness. After the tooth crown is joined by bolt connection, the tooth crown will not produce enough elastic deformation to completely eliminate the matching gap between the two sides of the tooth crown and the tooth ring seat. The bolt can only be closely matched with a single tooth crown, so the tooth crown and the tooth ring seat cannot be completely fastened. Due to the gap between the bolt and the tooth ring seat, the tooth crown will repeatedly slide relative to the tooth ring seat during crushing work, causing the matching surface to wear, and further increasing the matching gap, and replacing the tooth crown cannot eliminate the increased gap.
When mineral sizers break the material, the irreducible gap will put the crown and bolt in an unfavorable state of force, which will shorten the life of the crown and ring seat, and often break the tooth. Although the structure of the crown has been improved on the original basis, the gate structure of the crown has been changed to a groove shape, which is not easy to break teeth, but the strength and stiffness are greater. The connection between the tooth crown and the tooth ring seat is also the retightening force of the fastening bolt acting on a part of the tooth crown with greater strength and stiffness. The crown is still easy to loosen, resulting in wear of the connecting part and reducing the service life of the crown and ring seat.