Abstract: In order to discuss on the influence of wrap angle of tower hoist on the friction wheel stress,taking the JKM-4X4Ⅲ tower friction hoist (GB parameters) as a case，the finite element model of the main shaft device is built.Since the applied loads by hoist rope on drum shell conforms to Euler formula，the outer force of the friction wheel is obtained and transformed into the finite element model of the main shaft device.Then，the reasonable constraint condition is defined.With the aid of finite element analysis software（ABAQUS），stress calculation is made for the model with different wrap angles.The cyclic fatigue stress at different site of tower friction hoist and the distribution regularity of the cyclic fatigue stress with variation of wrap angle are achieved respectively:stress variation is relatively gentle when wrap angle is 180°~190°;stress variation gradient is increases obviously when wrap angle is 195°.The research results provides a reliable theoretical basis for the design of the main shaft device of the tower hoist and the selection of wrap angle when on-site installation.

Key words: Hoist, Friction wheel, ABAQUS, Cyclic fatigue stress, Wrap angle