Toothed belt drive

A toothed belt transmission comprises a belt that drives rotating mechanical elements. The driving pulley often imposes speed variations around the mean speed, and the resisting torques are generally variable over time. As a result, the dynamic response of the transmission generates dynamic forces on the belt and changes in the load distribution on the teeth.

The articles and have introduced the various characteristics that define timing belts. Operating characteristics have also been listed. The article presented simple, global pre-sizing methods. That article focused on quasi-static load distributions between the teeth transmitting the forces. The present article will now introduce the dynamic effects on the transmission itself and on the load distributions between the teeth. After an introduction defining the scope of the models and calculations, the second paragraph will present the establishment of the dynamic model with its characteristic equations, a visualization of the results and experimental validation. The next paragraph will deal with two cases of internal combustion engines with toothed belt drive.

There is no shortage of general studies on the dynamic behavior of belt drives. They mainly concern either V-belts or poly-V belts (1), with particular applications in the automotive industry. to , i.e. long belts with conveyor belts to . Based on the general theory of nonlinear continuous media, the small motions of the moving belt are obtained while taking into account the boundary conditions imposed by the driving and driven pulleys. In the general case, the motions of a moving belt element are coupled. We can visualize transverse and rotational vibrations in the plane, torsional vibrations (out-of-plane ), as do longitudinal movements. The effect of non-linearities due to the belt's constituent materials is quite visible, but adhesion conditions on the winding arcs also contribute to transmission damping. If the behavior of the belt material is well known and taken into account, simple schematizations of adhesion and friction conditions at the contact interfaces between pulleys and belt can be used. Naturally, discretized numerical calculations (using finite elements) are required to obtain results.

In the case of toothed belt drives, the meshing of the teeth complicates the situation, and calculation models are based on simplifications. . Experimental studies on the dynamic behaviour of these transmissions focus either on the vibrations of free strands or on the overall response of the transmission. . So, provided a few reasonable simplifications...