1316 緩衝器衝突時におけるエレベーター釣合車の動挙動解析

Abstract

Most elevators used in tall buildings include compensating ropes to satisfy the balanced rope tension between the car and the counter-weight. The compensating ropes receive tension by a compensating sheave, which is installed at the bottom space of the elevator shaft. The compensating sheave is only suspended by the compensating ropes, therefore, the sheave can move vertically. When the car can't stop at the highest floor in an abnormal situation, the counter-weight can reduce its downward speed by the buffer strike. During the buffer strike, the suspension ropes lose the tension and the car continues to move upward for a while against the gravity force. The upward motion of the car also induces the same upward motion against the compensating sheave. However the sheave can't move beyond a limited distance for safety reasons, and the restricted motion of the sheave induces higher tension to the compensating ropes. This paper shows the elevator dynamic model to calculate the compensating sheave motion during the buffer strike. Firstly, the transient behavior of the compensating ropes' tension and the compensating sheave's motion is validated by the multi-body dynamic model. Secondly, the equivalent 2-DOF vibration model is used to calculate the rope tension and the sheave motion. Finally, the relation between the permissible upward motion of the sheave and the rope tension is explained by the equivalent 2-DOF model. We can conclude that shorter permissible motion of the sheave causes higher rope tension to the compensating rope.