1. There are two ways of face gear modeling.

2. Meshing analysis of face gear has two parts.

3. A face gear drive with high contact ratio and good dynamic performance are considered.

4. Machining hardened face gear with high precision is one of the key developments of gear machining technology at present.

5. The concave and convex of face gear tooth surface benefits gear strength,() and the grinding process can be conducted on the general wheel and numerical control machine.

6. An investigation on the meshing characteristics of face gear drives is made in this paper.

7. It shows that the contact path of the face gear drive is shift in the direction of the surface caused by misalignment.

8. Everything from their head gear, face gear, outer top, and lower body can be altered to the player's exact specifications.

9. It is proved that the profile of Positive and Negative transmission is unique if the face gear, the difference between face tooth number and ball number and the diameter of ball are the same.

10. In the end, the feasibility of the theoretic results is received by the experiment of the face gear.

11. The equations of teeth surface after modification of all key components, such as wave producer, oscillating teeth, end face gear, are deduced.

12. The contact path offsets to the tip and toe of face gear tooth due to it is sensitive to the alignment error especially the error of axis shaft error in the misalignment.

13. The modification principle of tooth surface is deduced, and it draws the conclusion that the modificative tooth depth of wave producer, end face gear and oscillating teeth have certain relation.

14. The external gear plate is a column normal gear with very narrow gear width and the face gear plate is constituted with gear tooth of several circles.

15. Using a helical involute pinion surface to form the grinding worm surface, a helical face gear is formed via a two-parameter worm envelope.

16. The equations of flakes and fillets of the orthogonal face gear and the equation of the contact points about the orthogonal face gear drive are derived.

17. Face gear variator is a new gear variator and it is composed with external gear plate and face gear plate.

18. Overseas scholars including Litvin had contributed to the development of face gear drives, and found out that face gear drives have many advantages applied in helicopter transmissions.

19. Theoretical analysis of the impact of assembly errors on orthogonal face gear drive is critical to the application of face gear drive.

20. The research state and problems to be further researched on the face gear drive are discussed.

21. To improve tooth strength and make tooth grinding implement for face gear, a new generating method of face gear drive has been proposed, and the meshing characteristics are investigated.