Runner and teeth distributed of anti-drop tri-cone rotary drill bit

The utility model relates to an anti-drop tri-cone drill bit used for the well drilling of petroleum mines, which is an improvement of flow passage design and the teeth distribution of the drill bit, namely, a tooth slot and an intertooth space slot are communicated and have slippery transition, and the edge outlet height differences and the installation angles of an external row tooth and a middle row tooth are reconstructed reasonably, namely, the edge outlet of a tooth ring is divided into three-step and three-direction tooth distribution. The pattern of the bottom of a well is improved by the anti-drop tri-cone drill bit, and the optimal cutting, cleaning and chip removal of the tri-cone drill bit are obtained. The tooth distribution of the utility model improves the cutting ability and the abradability of tooth, and can cause the drilling speed to be improved for 10% to 40% with large range of application, and drilling bits of two contiguous models can be replaced.