Study On The Fatigue Design Of Knotting Machine Of Square Straw Bale Machine

The D type knob is one of the most important parts of the square baling machine.It is a kind of mechanism to realize the function of the knot depend entirely on the mechanical transmission,because of its complex structure,transmission precision,strict timing,difficult to manufacture,it mainly rely on imports,resulting in square bale machine manufacturing cost is high,seriously restricting the development of China's bundling machine.In view of the short service life of D knotting machine,this paper mainly aims at fatigue design of failure parts on D knotting machine,improving their fatigue life.They mainly include: the cam on the drive gear plate and the first tooth of the outer rack,the frame,the knot mouth and the chute groove.According to the driving gear plate rack on the first tooth wear problem,this paper through the proper heat treatment process,the surface to produce a certain residual stress to resist the impact of the work load to solve.The optimum temperature of heat treatment was found by simulating the residual stress field by ABAQUS.For the irregular tooth fracture problem of cracks based on fracture mechanics of the classified,and use ABAQUS to simulate the crack propagation,that may exist inside the tooth material defects,and the optimum residual stress can inhibit the crack propagation.According to the cam wear problems exist,this paper established the relationship between the amount of wear of cam and cam follower displacement reliability,calculated in the bale knotter cam after 22000 follower displacement reliability will be lower than 99%,maintenance of the cam mechanism,in order to protect the D type knotter in extended knotter a node under the premise of reliable service life.In view of the problem of the breakage of the worm assembly part of the D knotting rack body,the structure improvement of the frame is carried out in this paper,and the worm assembly surface is strengthened without affecting the knot function.Aiming at the problem of crack growth on the location of the oil hole on the worm shaft hole,the calculation of the crack tolerance is carried out through the residual strength theory.It is concluded that when the crack length reaches 10 mm,the location of the oil hole should be strengthened,so as to improve its fatigue life.The nozzle knotter fatigue wear,easily broken and occlusal rod is not easy to change with the problem,this paper presents the design of a detachable knotter,and use ANSYS software to check its strength and fatigue test.This can make users convenient to knotter damage to thetimely replacement,in order to ensure the normal work of bundling machine,does not affect the agricultural crops harvest season.Aiming at the problem of the stress concentration of the groove on the frame and the cleaning rope piece,and the problem that the outer rim body is easy to fracture,this paper puts forward the anti fatigue design plan of the U type groove,and through the ansys-ncode joint analysis,it is proved that the design can effectively improve the stress fatigue life of the groove.