FINITE ELEMENT CALCULATION AND

SPLINE OF HARMONIC DRIVE

LIU Wenzhi¹  ZHANG Nairen¹  ZHANG Chunlin¹ ZHAO Yongzhong²

(1. School of Mechanical and Vehicular Engineering, Beijing Institute of Technology, Beijing 100081;

2. The 41st Institute of the Sixth Academy of CASC, Huhhot 010062)

Abstract: The calculation of the flexspline stress, which is based on the simplified theory of the column-shaped shell, is to some degree not very accurate. So the fracture of the ring gear in column-shaped flexspline in reality has always remained a problem hard to solve. The column-shaped flexspline at harmonic drive is taken as an example here, and a model imitation of the engaged flexspline is set up. A surface-to-surface contact element is set up between the nodes on the contact surface of the engaged gears. Applying the finite element calculation of 3-D elastic contact problems, a thorough calculative and analysis is done in terms of the stress and its distribution of the bearing flexspline ring gear and the column, of the deformation of the gears tooth and the effect. The main reason of the flexspline fracture in the design phase has been found out, and the position possible dangerous section is predicted. According to the flexspline theory, a calculation with above result is conducted again the effect coefficient of the gear tooth is revised, and the flexspoine strength is double checked. In general compared the theoretical calculation to the actual fracture, a more close-to- the-reality result is reached, in addition, a more accurate, efficient method for solving flexspline problem is offered.

Key words: Harmonic drive  Column-shaped flexspline  Contact problems  Finite elements  Stress Strength  Effect coefficient of gear tooth

CLC No: TH132.43

Received 20050514, received in revised form 20051030