Studies on the Seedbed Making Tillage by Rotary Tiller (II)

On the Characteristics for the Variation of Tillage Tines

Abstract

The shape of blade of tilling tine was examined from the standpoint of the seedbed making tillage. An L-shaped cutting edge having a 90° deflection angle was taken as the basis, with radii of curvature of 8, 18, 28, 45, 65, and 85mm and their performances were compared with those of readymade knife tine and pick tine.
1) The smaller the redius of curvature, the higher the degree of soil pulverizing and leveling and power requirement.
2) The covering efficiency of rice stubble under practical tilling condition is the highest in N₄₅(r=b) tine and reaches 80 to 90%, and decreases for the tines with larger or smaller radius of curvature. The efficiency is the lowest in Hn tine and is around 30%.
3) The uniformity of soil pulverizing is inversely proportional to the degree of soil pulverizing expyessed by the weight mean diameter.
4) The power of the wheel axle becomes negative as the tilling torque increases exempt in Hn tine, and its rate increases as the radius of curvature decreases.
5) The fluctuation ratio of tilling torque varies a little by changing tilling depth and pitch and is about 1.40 in N_n. But the ratio decreasis by incre asing the tilling depth in Nr and Hn tines, within a range of 1.30 to 1.95. In the latter, the ratio is high at medium tilling pitch and is low at smaller or lager tillng pitch, and its region of variation is from 1.35 to 1.80.
6) The maximum tilling torque distributes in the higher torque range with higher frequency as the radius of curvature becomes shorter.