Study On The Pneumatic Nailer's Rubber Buffer Under Impact Load

Pneumatic nailer is a kind of portable air tool using high pressure gas as its power.It has been widely used in house decoration,building construction and other fields due to its numerous advantages.Rubber buffer is an important buffering part of pneumatic nailer,bearing the impact load of piston during work.The intense impact load makes the rubber buffer an wearing part of the pneumatic nailer and the property and durability of rubber buffer will directly influence the performance of pneumatic nailer.The transient process that the piston impacts the rubber buffer contains a lot of valuable information such as the impact responses of rubber buffer and piston,especially,the rubber buffer's dynamic stress will directly influence its durability.The research on the impact course will provide quantitative reference and theoretical guidance to the design and research of pneumatic nailer.A certain type of pneumatic nailer produced by domestic enterprise has been taken as the object in the paper.A numerical simulation is conducted in order to study the dynamic process that the piston impacts the rubber buffer.Then,an experiment is designed to verify the reliability of the simulation.Furthermore,a structural optimization of the rubber buffer is conducted in order to reduce the rubber buffer' s dynamic stress and improve its durability.The main tasks and achievements are presented as follows:(1)The appropriate rubber material model is chosen according to the specific load,uniaxial compression test and stress relaxation test based on the standard rubber specimen are conducted to fulfill the definition of rubber material.(2)Test is conducted to obtain the pressure history curves of two both surfaces of the piston during the work course.And the pressure curves are used as the boundary condition for the following simulation.(3)The simulation based on nonlinear finite element program LS-DYNA is conducted to study the dynamic process that the piston impact the rubber buffer,the dynamic responses of the rubber buffer and the piston are obtained.(4)Experimental platform is established,high-speed vedio experiment is designed to verify the reliability of the simulation.(5)The relationship between the durability of the rubber buffer and its dynamic stress is discussed.The maximum dynamic stress of the dangerous point is taken as the evaluation criteria to assess the durability of the rubber buffer.Improved structure of the rubber buffer are proposed.