Influence of Idler on Transmission Error in Synchronous Belt Drives : In Case of No Load

Abstract

Idlers are widely used in synchronous belt drives in order to adjust the center distance and in order to increase the angle of contact. A meshing phase angle occurs when an idler is attached and this is thought to generate a transmission error. In the present study, a transmission error having a period of one pitch of the pulley was investigated both theoretically and experimentally for synchronous belt drives with an idler attached on the belt span. The experimental conditions were such that the speed ratio was one under a quasi-static condition and no load. The experimentally obtained transmission error that occurs due to the idler agrees closely with the computed result. In addition, changes in tooth load and frictional force have a greater influence than change in meshing phase angle on the magnitude of the transmission error. The magnitude of the transmission error is affected when the idler is moved in the direction normal to the bearing stand, and is unaffected when the idler is moved in the direction parallel to the bearing stand. Furthermore, when the diameter of the idler increases, the transmission error remains constant. However, when the diameter of the idler decreases, the transmission error increases.