Theoretical Analysis of Transmission Error in Helical Synchronous Belt With Error on Belt Side Face Under Bidirectional Operation

Synchronous belt drives are occasionally required to transmit rotation accurately and are often employed in bidirectional operation. For transmission error per single pitch of the pulley, a helical synchronous belt with a helix angle of the tooth trace is effective. However, this belt causes axial movement because of the axial belt tooth load. When the belt comes into contact with the pulley flange or the belt moves away from the pulley flange due to bidirectional operation, the accuracy of finishing on the belt side face affects the transmission error. In the present study, the transmission error considering the error on the belt side face in a helical synchronous belt drive that uses flanged pulleys under the quasistatic condition and transmitted torque was investigated theoretically and experimentally for the case in which the pulley was rotated in bidirectional operation. The calculated transmission error coincided well with the experimentally obtained transmission error. Under forward rotation, the transmission error having a period of one rotation of the belt is caused by the error on the belt side face when the belt comes into contact with the pulley flange. Under reverse rotation, the transmission error is generated by a change in the belt tension due to the application of a transmitted torque and by the difference in axial belt movements between the driving and driven sides when the belt moves away from the pulley flange.