DEVELOPMENT OF A CAGE WHEEL AS A TRACTION AID TO AGRICULTURAL TRACTORS FOR POORLY DRAINED PADDY FIELDS

摘要

To improve tractive performance of agricultural tractors in poorly drained paddy fields, a cage wheel attachable to the driving tires as a traction aid was developed and tested. Effects of four design parameters of the cage wheel, wheel diameter, wheel width, lug angle and lug pitch on the tractive performance were experimentally investigated in two different types of poorly drained paddy fields: one with shallow hardpan of 15-20 cm deep and another with deep hardpan of 30-50 cm deep. The tractive performance was represented by the drawbar pull and tractive efficiency of a test tractor, which were determined by fitting the measured data into the Wismer-Luth model. Results of the experimental investigation were as follows: Attaching the cage wheel increased tractive performance of the test tractor by more than at least 32%. In a field with the shallow hardpan, smaller lug pitch showed better tractive performance. In a field with the deep hardpan, larger lug pitch showed better performance. However, decreasing or increasing the lug pitch beyond a certain limit reduced the performance because of a soil entanglement to or a large sinkage of the cage wheel. The effects of the design parameters on the tractive performance were also variable depending upon the field and operational conditions.