The limit contact state of microminiature gear under axial high inertia force condition is studied. Based on the rigid elementmethod and the Hertz contact theory

the the oreticalcritical contact model is established. Moreover

manual programming method and optimization method to find the accurate limit contact state are proposed based on the FEM.The limit tooth width and the oretical critical contact angle are obtained.Furthermore

through comparing the theoretical analysis results with the finite element analysis results

the feasibility and the accuracy of theoretical model established and manual programming method and optimization method proposed are verified.The basis is supported for improving the reliability of the microminiature gear system in harsh conditions.