Hiroyuki Ueda

Synchronous belt drives are widely used in various machines in order to transmit rotation accurately and synchronously. In these machines, idlers are commonly used to increase the angle of contact on the pulley and to avoid obstacles. However the generating source of the transmission error under a transmission force with an idler remains unclear In the present study, transmission error over a period of one pitch of the pulley was investigated both theoretically and experimentally for a synchronous belt drive attached an idler when a transmission force acted on the belt span. The experimental results agree closely with the computed results. The transmission error is greatly affected by change in the meshing state in the incomplete meshing sections. The idler position at which the transmission error is reduced exists even if the transmission torque increases. In addition, transmission error is reduced when the helix angle is increased.

はすば歯付ベルトの伝達トルク作用時の片寄りについて、原動プーリ上と従動プーリ上におけるベルトの軸方向移動のつりあいから理論解析を行い、計算結果と実験結果を比較検討した。その結果、走行中のベルトにおいて原動プーリ上と従動プーリ上との間にオフセットを生じる。ベルトの片寄りは、このオフセットと両プーリにおけるかみあい始めのベルト歯のせん断ひずみにより生じることがわかった。ベルトの片寄り量は、伝達トルクの増加とともに増加するが、伝達トルクが一定ならば、取付張力を低く設定することによって低減できる。

Helical timing belts have been developed in order to reduce the noise that occurs when conventional timing belts are driven. Helical timing belts are characterized by synchronous rotation. Although several studies have been performed to clarify the noise characteristics and belt life of helical timing belts, the transmission error of these belts remains unclear. In the present study, the transmission error having a period of one pitch of the pulley was investigated both theoretically and experimentally for helical timing belt drives. Experimental conditions were such that the transmission force acts on the helical timing belts under quasi-static conditions and the belt incurs belt climbing at the beginning of meshing and at the end of meshing. Experimental results obtained for the transmission error agreed closely with the computed results. The computed results revealed that helical timing belts can be analyzed as a set of very narrow belts for which the helix angle is zero. The transmission error was found to decrease when the helix angle or the belt width increase within a range defined such that the face advance is less than one belt pitch. In addition, there exists an appropriate installation tension that reduces the transmission error.