Mechanism and stress analysis of the ratchet wrench

• Main Authors: CHANG,YU-TING, 張銪庭
• Other Authors: CHANG,CHIA-LUNG
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/pktfw5

碩士 === 國立雲林科技大學 === 機械工程系 === 103 === First part of this study, the creative mechanism design is used to analyze the fast action twist ratchet wrench. Compared with all possible mechanism topologies and the optimal mechanism design is chosen. Second part of this study, the stress analysis of ratchet wrench is performed. The studied tooth number of ratchet is increased from 48 to 80 and 90. The contact mechanical behaviors of the wrench for different combinations between the pawl, tooth number from 3 to 7, and the ratchet, tooth number either 80 or 90, are studied. The effects of different combinations on the stress distributions of the wrench are compared. The stress simulation of the involute gear is performed first. Then the contact and bending stress of the involute gear are calculated by formulas from AGMA. The simulated and calculated stresses are compared to verify the boundary conditions of the gear model. The similar boundary conditions are adopted for the wrench model. The contact and bending stresses as well fatigue life of the ratchet, pawl and the wrench body are carried out by simulation. The results show that the stresses are decreased with increasing the contact areas.