On Which Pulley Does Belt Slippage Occur First?
1 Answers
Belt slippage first occurs on the smaller pulley. Introduction to the Contact Arc: The contact arc can be divided into two parts: the part with relative sliding (sliding arc) and the part without relative sliding (static arc). The central angles corresponding to these two arcs are called the sliding angle and the static angle, respectively. The static arc is always located at the beginning part where the belt wraps around the driving and driven pulleys, while the sliding arc is located on the part of the contact arc where the belt leaves the driving and driven pulleys. When the belt is not transmitting load, the sliding angle is zero. Elastic Sliding: Elastic sliding only occurs on the sliding arc of the belt. As the load increases, the sliding angle gradually increases, while the static angle gradually decreases. When the sliding angle increases to the wrap angle of the pulley, the limit state is reached, and the effective tension of the belt drive reaches its maximum (critical) value. If the working load continues to increase, significant relative sliding between the belt and the pulley will occur, resulting in slippage. Since the wrap angle on the larger pulley is always greater than that on the smaller pulley, slippage always occurs first on the smaller pulley.
