Analysis On Engagement Characteristic And Wear Life Of Sprag Clutch Of The Logarithmic Surface’s Wedge

In the process of engagement, the working wedge angle of the logarithmic surface’wedge remains unchange. The sprag clutch is suitable for high-speed and widely used in aviation and engineering equipment fields. In order to design the small contact impact, largely carrying capacity and reliable on-off sprag clutch. The paper has designed sprag clutch of the wedge of a new type of surface (the logarithmic surface) and researched wear life of sprag clutch. The main contents are as follows.Analyzed the working wedge angle of sprag clutch and established the function of wedge angle. Based on the demand of working condition and structure of clutch, designed the wedge of logarithmic surface under different wedge angle. Adopted the step by step iteration method, obtained the contact stress between wedge and raceway, the hoop stress of raceway and the total deformation of sprag clutch.Based on Pro/E and ADAMS, established dynamic simulation model of sprag clutch. By analyzing, the synchronization time and response time, windup angle and the contact force were obtained. Through the contrastive study, obtained the rule of the change of wedge angle effect on the engagement performance of sprag clutch.Based on Pro/E and ABAQUS, established contact property model of sprag clutch. The contact stress between the wedge and the raceway is obtained under the working conditions. Studied on the change of wedge angle effect on the contact stress and the distributional rule of contact stress along the direction of wedge length.Aimed at the clutch appear wear phenomenon under overrunning conditions, based on the Hertz contact theory and the Archard wear theory, established the wear model of wedge. According to the homogeneous coordinate transformation principle and the boundary conditions of positive continuous engagement of sprag clutch, the formula of the wear limit of wedge was deduced. Calculated and obtained the wear life of clutch under overrunning conditions by using MATLAB. Analyzed the wear rule of the working surface of wedge. Manufactured the sprag clutch, and performed an experiment of the on-off property of the clutch. Tested the bonding time, windup angle and the contact stress of the sprag clutch. The result of experiment show that the theoretical design of sprag clutch was corrected.69images,27tables and71references.