The jaw crusher is composed of a working chamber composed of a movable jaw and a fixed jaw. The movable jaw and the fixed jaw are subject to huge crushing force and friction of materials, and are easy to wear out. In order to protect the jaw plate, a wear-resistant lining plate is generally installed on the surface of the movable jaw and the fixed jaw, and this lining plate is also called a crushing plate. The surface of the crushing plate is usually made into a tooth shape, and the angle of the tooth peak of the crushing plate is 90°~120°, and its size is determined by the nature and lumpiness of the material to be crushed. It should be larger; when crushing small pieces of material, the angle can be smaller. The size of the tooth pitch depends on the particle size of the product, usually it is approximately equal to the width of the discharge port, and the ratio of the tooth height to the tooth pitch can be taken as 1/2 to 1/3. When working, the wear speed of the upper and lower parts of the crushing plate is different. The lower part wears faster than the upper part. When the jaw crusher is working, the crushing plate directly contacts with the material and bears huge crushing force and friction of the material. The service life of the crushing plate is directly related to the working efficiency and production cost of the jaw crusher. Therefore, it is particularly important to prolong the service life of the crushing plate of the jaw crusher. Enhancing the service life of the jaw crusher plate can be considered from the aspects of design, material selection, assembly and improvement during use.

1. Design and material selection of the crushing plate of the jaw crusher

When designing, the broken plates of the movable jaw and the fixed jaw should have tooth peaks facing tooth valleys. In this way, in addition to the extrusion effect on the material during crushing, there is also a bending effect, and the material is easier to crush. In order to enhance the service life of the crushing plate, the crushing plate of the small and medium-sized crusher is designed to be symmetrical up and down, and can be used when the lower part is worn; the crushing plate of the large jaw crusher is designed to be symmetrical with each other, so as to grind high-pressure fine powder After wear and tear, the crushing plate can be exchanged for use. The material of the crushing plate can be white cast iron. White cast iron has higher hardness, better wear resistance, easy source, and cheap price; the disadvantage is that it is brittle, easy to break, and has a short service life. In order to improve the service life of the crushing plate, it is better to use manganese steel with more than 12% manganese as the material, and ZGMn13 is commonly used. The toughness of manganese steel is good, although the hardness is not high (about 210HB), but because of the characteristics of cold work hardening, the linear vibrating screen will be continuously strengthened under the action of pressure, so it will continue to wear and strengthen during work until it wears out. It is scrapped until it cannot be used. After casting, manganese steel crushing plate should undergo water toughening treatment. The operation of water toughening treatment is basically the same as quenching, that is, the cast manganese steel crushing plate is heated to 1000-1100 ℃ and then cooled rapidly in water. After the water toughening treatment, a uniform metallographic structure can be obtained, and the metallographic structure can be fixed, avoiding the natural phase change during use and making the performance worse. The disadvantage of manganese steel is that it is more expensive, but in terms of service life and cost, ZGMn13 has a longer service life and lower cost than white cast iron

2. Assembly of the crushing plate of the jaw crusher

When assembling, the crushing plate must be firmly attached to the jaw plate, and the space between the two should be flat. Soft metal (such as lead, zinc, etc.) should be used as a gasket between the crushing plate and the jaw plate, and fastened with bolts. When the crusher is working, the crushing plate should not be loose, otherwise it is easy to break or wear the crushing plate, which will reduce the service life of the crushing plate. Therefore, the crushing plate must be installed during assembly to prolong the service life of the crushing plate

3. Improvement during use to enhance the life of the crushing plate

In the sand making machine in the production process, the crushing plate directly interacts with the material, and the crushing force is very large, especially when crushing materials with high hardness, the bolts on which the crushing plate is installed will vibrate and the nuts will become loose, which will aggravate the wear of the crushing plate and generate a huge In severe cases, the broken plate falls off or breaks, causing the equipment to stop and affecting normal production. In this case, just tightening the bolts and nuts before starting the machine cannot completely solve the problem. It is necessary to analyze the specific problems according to the actual situation on site, and find ways to solve the problem with practical methods. For example, the spring anti-loose vibration damping device can be used to solve the loosening of the crushing plate during work, thereby prolonging the service life of the crushing plate and improving the working efficiency. The specific method is to use the spring to make the bolt anti-loosening and self-tightening device. The device is composed of an inner spring gland compound crusher, a spring and an outer spring gland. Put this device on the bolt and tighten the nut. After being tightened to a certain degree, a strong anti-vibration effect is produced. The bolt loosening force generated by the huge crushing force is automatically compensated by the spring tension force, so the bolts will not loosen, thereby prolonging the service life of the crushing plate and improving production efficiency. In short, in the process of use, we can find ways to solve specific problems according to specific situations, and prevent the crushing plate from loosening, aggravated wear, and breaking, so as to prolong the service life of the crushing plate, reduce costs, and improve work efficiency.

4 Conclusion

Enhancing the service life of the crushing plate of the jaw crusher starts from the aspects of design, material selection, assembly, and improvement in the use process, which can well enhance the service life of the crushing plate of the jaw crusher, thereby improving the production efficiency of the jaw crusher and reducing production costs.