Roller teeth are the key parts of mineral sizers, and the damage of roller teeth is the most serious. Using the finite element method to simulate the stuck-turn phenomenon and analyze the strength of the roller teeth, the results show that this strength design can provide a reference.
The introduction
mineral sizers is a kind of high efficiency crushing equipment, widely used in coal, chemical industry and other crushing operations. The roller tooth is its main working part, directly contact with the material. Therefore, the design quality of roller teeth is directly related to the production efficiency and service life of the sizer.
In the crushing process, it is inevitable to encounter hard and difficult materials such as iron, resulting in a card, the roller teeth brought a great impact. This factor should be considered in the design to make the equipment safe and reliable. However, there is still a lack of feasible calculation methods, more rely on the experience of designers to carry out. In this paper, finite element method is mainly used to simulate the stuck-turning process, trying to provide a more effective strength analysis method.

1. Selection of calculation conditions
The working condition taken in this paper is that, when the sizer is working normally, a hard foreign body such as iron suddenly falls into the teeth of the roller and causes a stuck turn, and the foreign body is clamped on the teeth tips of the three staggered rolls. Only one tooth on one of the tooth rolls is stressed, and the impact of the tooth roll and its connected rotating parts is completely acted on one of the tooth rolls.
2 Model simplification
Figure 1 is the structure diagram of the crusher. Mineral sizers roller, coupling, reducer and motor are taken during calculation. For the convenience of calculation, the model is simplified. The crushing roller of this type sizer adopts the structure of tooth disc, with a total of 5 tooth discs, one tooth disc is taken as the research object, and other tooth discs and rotating parts are applied to the tooth disc in the form of rotational inertia unit. The calculation model is shown in Figure 2.
3 Boundary conditions
Tooth disc: When the speed of tooth disc is 50r/min, the angular velocity AW = XN /30=5.23md/s. Cutie: constrain its three translational degrees of freedom (see Figure 2).
4 Result Analysis
It can be seen from the dynamic demonstration process in the post-processing that when the roller teeth collide with the iron block, the roller suddenly stops rotating, and the stress value rises rapidly to a sharp peak and then falls back. The large stress of the roller is concentrated in the tip of the tooth, and the maximum Mise stress value is 782MPa(see Figure 3), which exceeds the yield limit of the material. The Mise stress value of other positions is below 150MPa, which is lower than the yield limit of the material. FIG. 4 shows that the equivalent plastic strain PEEQ&gt in the local area of the tooth tip. 0. It can be considered that the roller teeth are not likely to be broken when the iron is stuck, but the plastic deformation caused by contact pressure may occur in the tip part of the teeth. In the normal operation of crusher, the failure of roller teeth is mainly wear.
5 conclusion
Because the failure mode of the crusher roller teeth is mainly wear, the service life of the roller teeth can be improved by inlaying or surfacing wear-resistant materials on the surface of the roller teeth. mineral sizers is proved that the method is feasible and can provide reference for the design improvement of mineral sizers.

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