Design and test of planet gear driver of reciprocating double-acting cutter for rapeseed combine harvester

Abstract: In order to solve the problems, such as serious vibration, high rapeseed loss rate of header and the high cutting power consumption, caused by the single-acting reciprocating cutter of the traditional rapeseed combine harvester, the planet gear driver of the reciprocating double-acting cutter was designed and tested. Firstly, kinematic equation of planet gear driver was established, and the structural parameters of the planet gear driver of the reciprocating double-acting cutter which must satisfy the requirement of cutter kinematics were analyzed. The analysis of the inertia force, and cutting trajectory and cutting area of the double-acting cutter showed that the inertia force generated by the reciprocating motion of the cutter bar was the main vibration source of the cutter. And the planet gear driven double-acting cutter's characteristics of good balance of inertia force, small cutting impact, light disturbance to the rape stalk and high cutting continuity were verified. Moreover, the bench experiment of power consumption for rape stalks cutting was done to compare the mean power consumption of the planet gear driven reciprocating double-acting cutter with that of the crank-linker driven single-acting cutter and double-acting cutter. When the cutting speed was in the range of 1.2-1.6 m/s, the average power consumption of the planet gear driven double-acting cutter was 43.3% and 16.8% lower than that of the crank-linker driven single-acting cutter and double-acting cutter, respectively. Furthermore, in order to test the vibration acceleration of the planet gear driven double-acting cutter and the crank-linker driven single-acting cutter, the two cutters were installed on the header of NJS-2.2 self-propelled rape combine harvest test bench respectively. When the speed of the cutter was in the range of 0.8-1.6 m/s, the average vibration acceleration of the planet gear driven double-acting cutter was 56.3% and 51.2% lower than that of the crank-linker driven single-acting cutter at the same vibration measuring point and in the same direction, respectively in the idling state and working state in the field experiments. Then, in order to research the other working performance between the planet gear driven double-acting cutter and the crank-linker driven single-acting cutter, the field experiments of the rapeseed loss rate of header were carried out. The results showed that the minimum and the maximum of the loss rate of header with the planet gear driven double-acting cutter were 1.56% and 2.68% respectively, which was 42.5% lower than that of the header with crank-linker driven single-acting cutter when the forward speed of the harvester was in the range of 0.6-1.4 m/s. The theoretical analysis, laboratory experiment and working state experiment in the field showed that the planet gear driven double-acting cutter designed in the study had the advantages of smaller vibration acceleration, lower power consumption, stable working performance, and obvious effect on reducing the rapeseed loss rate of header for rapeseed combine harvester than that of the crank-linker driven single-acting cutter. Thus it indicated that the planet gear driven double-acting cutter had the value of further improving and promoting application.