| The 9GSCC-1.4H reciprocating cutting device of aquatic weed harvesters (AWH) is different from mechanical cutting device of grass harvesters. AWH is catamaran, the cutting device is in the middle of catamaran and is placed postpositionally, the cutting blades drive system is behind the cutter, the crank connecting link has a certain degree with the horizontal plane, the fork master arm in cutting blades drive system is not in the same plane with the driven arm. With kinematics and dynamics analysis of the cutting device of 9GSCC-1.4H AWH, we found, when cutting, the trace of where fork contacts the driver bar of moving blades was line contact of spatial arc line, meanwhile shock vibration turned up between fork and driver bar which accelerated the abrasion of fork and driver bar and shortened the working life of cutting device. So according to these problems of cutting device, we improved the structural design of cutting blades drive system. We changed the fork driven arm to rocker and put crank connecting link and the small fork in a hinge joint, thus the small fork drove rocker in a back-and-forth movement through the middle link, the effect spatial curves trajectory had on the link was eliminated by connecting the small fork and middle link with ball bearing, and the cutting movement was realized as wiggling rocker drove the cutter.We built the 3D model for improved cutting device using Pro/E software, fit it together, set mass properties, friction coefficient, and original movement conditions for the cutting device model after assembling, and analyzed the dynamic simulation of cutting device to obtain the velocity and accelerating curves of moving blades and friction force, it turned out that simulation analysis agreed with motion characteristics in working. We also carried out dynamics analysis of cutting device blades drive system, found out that moving blades driver bars and square covered assembly units are most complicated when stressed and are most likely to break down in the whole cutting device. After using ANSYS to do statics analysis to moving blades driver bars and square covered assembly units, we knew that the root of driver bar was dangerous section but it had met the designing and usage need because the max stress is lower than material's allowable stress.By improving the structural design of cutting device we optimized its structure, enhanced its working life and provided basis for researching large AWH. |
