Search Results

Traction systems for agricultural vehicles compact soil much more than the optimal density for crop yield. For this reason crop yields decrease both in the season in which compaction occurs and in subsequent years. That is why the soil compaction problem may be considered an ecological one. Among the well-known traction systems used to decrease soil compaction are; decrease of air pressure in tires, dual wheels, multi-axle wheel and crawler traction systems, improvement of tire deformation properties, etc. However, the analysis performed revealed contradictory results of using the above ways under varying operating conditions. Thus, it is not clear at what soil conditions it is appropriate to apply dual wheels, multi-axle wheel traction systems, or special appliances to increase the propulsion system's contact surface and thereby decrease its compaction. Different traction systems have varying effects on compaction for arable and sub-arable soil layers.

Efficiency increase of an agricultural tractor may be achieved through installation of a pneumatic track propulsion system to combine the benefits of both pneumatic wheels and rubber tracks. A pneumatic track comprises a power belt and a number of pneumatic elements attached thereto. Serviceability of the pneumatic track is dependent upon the properties of its pneumatic elements. The article gives the methodology and static test results of several types and dimensions of pneumatic elements. The tests were run on a custom-designed testing stand. Geometric parameters, properties of static rigidity rate (normal, lateral, and tangential), and pressure distribution coefficient versus air pressure in the pneumatic elements have been determined. Through mathematical processing of experimental data regressional equations have been obtained. The methodology and the results of the experimental studies are given for a tractor having a pneumatic track propeller.

Distribution of traction forces among driving wheels is one of the main factors governing the performance of a highway truck during acceleration and braking on varying macro and micro road surface conditions. Comprehension of the interaction between wheels and road surface provides a profound systematic way to simulate a truck's motion and design required components for the optimal performance. The development of electronic technologies has created the pre-conditions necessary to develop systems with controlled parameters. However, to realize the pre-conditions, vehicle dynamics problems have to be formulated and solved for both optimization and control. Many different approaches emerged with the aid of electronics to control the circumferential wheel forces (wheel torque) by restricting wheel slip. A part of such systems has been named as Acceleration Slip Regulation (ASR) and Anti Slip Differentials (ASD).

Comparative test have been run of rice-harvesters with wheel, metal-track and pneumatic-track propulsion systems. The pneumatic track was made in two versions: with air-filled elements (tracks), and with foam-filled ones. Tests were held on the concrete testing ground track and on the tilled field. Resistance to harvester's motion, resistance to turning round, pressure of propulsion systems on soil, soil deformation, and soil hardness in the rut (trace) were determined after harvester's pass. The investigations showed that soil deformation and hardness in the rut were minimum when the pneumatic propulsion system was used, and maximum when using the wheel propulsion system. Resistance to motion, on the other hand, was maximum with the pneumatic-track propulsion system, and minimum with the wheel one.