Testing of the removable caterpillar undercarriage system of a class 0.9 agricultural tractor

Abstract

The paper presents the results of functional tests of the removable caterpillar undercarriage system of the rear drive axle of the Belarus-622 tractor with the ability to regulate the contact area of the caterpillar with the supporting surface. Domestic and foreign experience in testing and operating undercarriage systems for various vehicles and machines is analyzed, including the experience of researchers from Denmark, Switzerland, Sweden, Norway, including in relation to vehicles equipped with removable tracked undercarriage systems. The lack of a general test methodology and taking into account specific factors, including the redistribution of pressure on the soil along the support branch of the caterpillar, was revealed. A calculation and comparison of the average pressure of the movers on the soil was carried out for a tractor of a basic wheeled design equipped with a traction caterpillar units (removable caterpillar undercarriage system) for the rear and both drive axles. This showed that even without increasing the contact area, a tractor with removable tracked undercarriage system only on the rear axle has a significantly smaller impact on the soil than the wheeled tractor – 59.93 versus 82.11 kPa. Tests under real operating conditions were carried out on an experimental unplowed field with medium loamy soil in the Ryazan region. A kinematic mismatch between the front and rear drive wheels led to the front wheels slipping and required the front axle to be disengaged. To assess the traction capacity of the tractor and its possible increase as a result of the installation of a removable caterpillar undercarriage system, tests were carried out on the transportation of agricultural machines for tractors of a higher traction class: semi-trailer sprayers Caffini and an integral planter Demetra 2276-2019. When working with the seeder, the front wheels lost contact with the supporting surface and they became suspended, with the entire weight of the tractor and seeder only to the rear tracked units. Despite this, a high load-bearing capacity of the tracked modules and the tangential stabilizer, in particular, was revealed. The flaw detection revealed isolated signs of natural wear of the friction surfaces. No operational failures were identified. Directions for further research into removable caterpillar undercarriage systems are formulated in terms of improving operational test methods, design and engineering parameters of tracked units, including through the introduction of automation and robotics to create undercarriage systems adaptive to various soil and climatic conditions.