Aiming at some common used types of planetary gear transmission, dynamic differential equations of central internal gear rings are established, and mechanical vibrations theory is used to study situations of their radial forced vibration in this paper. The result shows that the radial resonance of internal gear rings of 2K-H（NGW） type,2K-H（NW） type and 3K（NGWN） type transmission device can hardly occur while the radial resonance of internal gear rings of 2K-H（...
