摘要：It is noted that any variation in operating conditions has a considerable effect on the tire/road interaction. Furthermore,choosing a range of proper values for carcass stiffness is very essential for both tire safety and effective driving action. In this work,an elaborated 3D model fully compliant with the geometrical size of radial tire 185/60 R15 is worked up, for evaluating the effects of components properties and working conditions on deformation and stress/strain fields created inside the tire. For the simulation, the tire structure is assumed to be composed of tread, carcass ply, and bead. The mechanical behavior of rubber as main component of tire is described by Mooney-Rivlin material model. The comparison of the obtained results and laboratory tests demonstrates the validity and high accuracy of analysis.

摘要：The goal of the modern farming systems is to economize energy consumption and to reduce farming *** selection and use of agricultural machines are important factors to achieve this *** tillers are tillage tools that are used for accomplishment of both the primary and secondary tillage *** the widespread application of rotary tillers and wide use of modern tractors in Iran,optimal design of these machines is *** in this study,the optimal working width and optimal diameter of the rotary tiller's rotor proportionate with the power of the MF 399 tractor was delineated based on the energy *** theoretical method is based on the specific works of tractor and rotary *** showed that the optimal working width and optimal diameter of the rotary tiller’s rotor with maximum of forward speed 1 m/s for tractor was 240 cm and 6.27 cm,respectively.

摘要：There are many design parameters in precision planters to be considered such as cell diameter, peripheral speed of roller, number of cells, manner of feeding seeds into cell and travel speed. In precision planters each cell must contain only one seed. Therefore, sliding the seed to the cell is important and depends on several parameters such as seed repose angle, seed dimensions and physics of cell. To help the seed to repose in the cell, making a groove on the roller would be very useful. Dimensions of this groove are very important and are considered as basic design parameters. This research was performed to determine some design parameters such as roller speed, travel speed, length and depth of groove for tomato seeds precision planting. In this regard, seeds with a diameter of 4 mm were used. The range of variation was based on calculations obtained. A roller with 42 mm width, 118 mm diameter and 15 cells on the surface was used in the experiment. For each cell, a triangular groove was created on the roller. The groove depth varied from zero at the beginning to the maximum value where the groove connected to the cell. The test unit had a continued and wide belt with 1 l m length. In each replication, planter worked for 20 s to reach a stable state. Thereafter, seeds were allowed to drop on the grease belt. Number of seeds and their spacing were measured on the 4.5 m of the belt. Results showed that the roller speed of 41.5 rpm, the planter travel speed of approximately 1 km/h, groove length of 6-8 mm and groove depth of 1.5 mm can improve planter performance for tomato pelleted seed.

摘要：The computer aided engineering analysis and design optimization of rotary tillage tool on the basis of finite element method and simulation method is done by using CAD-software for the structural *** different tillage tool parts of rotary tillage tools are geometrically constructed as a solid *** actual field performance rating parameters along with boundary conditions are set in the software for 35 hp and 45 hp *** estimated forces acting on soil-tool interface are fed into software as a loading *** resultant effects of loading condition on tillage blade and whole rotavator assembly were obtained from stress distribution and deformations *** proposed working results in identifying sufficient tolerance in changing the dimensions of rotavator frame sections and side gear box for removing the excess weight in a solid section and also to raise the weight of blade for a reliable *** present working model with tillage blade is analysed to new design constraints with change of its geometry for the maximum weed removal efficiency by presenting its practical results from the field performance.

摘要：采用单轮测试仪和土槽研究拖拉机车轮的速度、充气压力和垂直负荷对一定条件下轮胎滚动阻力的影响。车轮在农业机械和工程机械中起重要作用，这是由于轮胎直接与农田接触，几乎全部的负荷和力矩都集中在轮胎上，因此其对车辆的动力学起重要影响。由于车轮具有行驶、转向和牵引的基本作用，因此有必要研究土壤一车轮的相互作用。拖拉机是重要的农业车辆之一，