Study On The Structure And Performance For Disassembly Of The Sleeve-base Connection With Interference Fit Under Cold Excitation

The sleeve-base structure with interference fit is often used in mechanical and electrical products with large loads,strong impacts and high position accuracy.In this connection,as the core component,the sleeve parts suffer great damage and are difficult to repair.The cost of remanufacturing is high.The researches on the nondestructive or less-destructive disassembly of the sleeve-base structure are beneficial to improve the economic and environmental benefits of remanufacturing of mechanical and electrical products.This thesis focuses on the nondestructive disassembly of structure with interference fit in mechanical and electrical products.Taking the nondestructive disassembly of the sleeve-base connection as a typical representative,the structure and performance of sleeve-base connection is studied based on the existing theories and methods of disassembly under cold excitation.To explore the optimization design for nondestructive disassembly under cold excitation,the thermal properties,surface texture design and structure optimization of interference fitting parts are considered.The main contents are as follows:(1)The influences of thermal contact resistance on the transient heat transfer and the performance of disassembly under cold excitation are considered by theoretical analysis.The relationships between the thermal contact resistance and the thermal conductivity,contact surface condition,contact stress(interference)of parts are researched.(2)Significant differences in thermal properties of sleeve-base parts are designed to study the effects on fitting characteristics and disassembly performance of contact surface.And the material selection of parts is carried out.The ceramic coating is introduced between the fitting surface of sleeve and base,and the contact stress and heat transfer characteristics of the fitting surface are changed.By adjusting the thickness of the ceramic coating,the change of contact stress is observed.(3)Through analyzing the surface texture on bearing capacity and thermal contact resistance,the change law of temperature difference between contact surfaces is explored.The effects of surface texture parameters(such as shape,size,spacing,etc.)on the disassembly under cold excitation are discussed,The relationship between disassembly force and contact stress with texture parameters is obtained,and the optimal surface texture to improve the disassembly performance under cold excitation is explored.The disassembly experiment of textured surface is conducted to observe the disassembly force and damage.(4)The structural design of the sleeve-base parts on the bearing capacity is discussed.Grooves with different sizes of are set on the surface of the sleeve.Through the change of the contact area,the transient temperature field under cold excitation is changed,so as to affect the radial size of the parts,thus affecting the disassembly force and damage.The effects on the nondestructive disassembly are summarized through the disassembly experiment of the structural design.