| Author | Cumnueng Watayotha |
| Call Number | AIT Diss. no.AE-00-01 |
| Subject(s) | Tractors--Performance
|
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AE-00-01 |
| Abstract | Improvement in the traction performance of the conventional cage wheel is a challenge to help poor farmers working in wet paddy fields in the world to gain opportunity cost from a loss of available power from their tractors. Thai study was aimed at finding the effect of a lug parameter that has been considered less important in improving the performance of cage wheels. This was the lug arrangement or configuration like a rubber tire on the cage wheels, called opposing circumferential lugs. The experiments were carried out in a laboratory soil bin with clay soil of 49% average soil moisture content and 135 kN average cone index. Cage wheels with opposing circumferential lugs at four levels of circumferential angle, 0°, 15°, 30° and 45°, were evaluated and performance was compared with normal cage wheels. The lug spacing and wheel slip of the test wheels were varied from 20°, 24°, 30°, to 40° and 25%, 40% to 55%, respectively. All test were conducted at a constant lug sinkage of 7 cm and 20 rpm rotational speed to the wheel. The characteristics of three orthogonal force components produced by the cage wheels with opposing circumferential lugs were obtained by using a triaxial dynamometer. The pull and lift forces of the opposing lugs at circumferential angles of 15° and 30° were significantly higher than those of the normal lugs due to increase in the shear area in the corresponding direction which caused increase in the longer lug length at circumferential angle. At 45° circumferential angle the lift forces of the opposing lugs were still significantly higher. The pull force were drastically affected by the influence of the opposing circumferential lugs interference that was closely related to the lug overlapping and the end-of-lug clearance leads to decrease in the forces. The better balancing of side forces could be obtained by increasing the circumferential angle and decreasing the lug spacing. The directional stability and steering performance of power tillers is expected to improve with modified lugs because of their ability to generate higher lateral forces. The variations in the pull and lift forces of the modified wheels at 0°, 15°, 30° and 45° circumferential angles were significantly lower than those of the normal cage wheels because of the decreasing lug opening caused by the larger circumferential angle and smaller lug spacing. The modified wheels with 15° circumferential angle at 24° and 30° lug spacings showed significantly higher power compared to other combinations. Although the power of the modified wheels was higher than the conventional wheels, the traction efficiencies between the modified and normal wheels were not significantly different. Based on the performance and cost of materials, the cage wheel with opposing circumferential angle lugs at 15° circumferential angle and 30° lug spacing is recommended for the design of power tillers in Thailand |
| Year | 2000 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AE-00-01 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Salokhe, Vilas M.; |
| Examination Committee(s) | Singh, G;Balasubramaniam, A. S.; |
| Scholarship Donor(s) | Ministry of University Affairs, Thailand; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2000 |