The design features of a motor-grader help it perform a wide range of working operations, which puts it on a par with the main machines in the construction industry. Unlike other earth-moving machines, the motor-grader can perform work operations not only in a cyclic mode, but also in a continuous action mode. Considering these features, not only productivity should be addressed as the main indicator of the efficiency of this machine, but also the indicators of the quality of the working operations performed, in particular, the indicators of road-holding ability in the process of performing continuous working operations. The work has substantiated and developed a mathematical model of the motor-grader movement during working operations. This model makes it possible to predict the expected trajectory of the motor-grader on the basis of deterministic dependencies, which enables to assess the indicators of road-holding ability. The difference between the proposed model and the existing ones is the consideration of a two-stage mode of machine movement: plane motion at the first stage and rotational around the stop point at the second. When describing the external forces acting on the motor-grader, the differences in the formation of resistance forces on the blade during various working operations are taken into account.
Problem. The problem is an integral part of developing the concept of forming a standard range of transport and technological hydrophilic modular means for maintenance of airfields and aircraft. Goal. The goal is development of scientifically sound recommendations for determining the rational parameters of the hydraulic system with automation of control and energy saving during operation of modular vehicles for maintenance of airfields and aircraft, taking into account the potential of domestic engineering and critical imports of units and assemblies. Methodology. The methods include analysis of energy saving methods in hydraulic fluid power of mobile machines according to manufacturers' catalogs and industrial examples taking into account the needs of modular vehicles for maintenance of airfields and aircraft, in particular, taking into account the creation of modern hydraulic devices and circuit solutions in hydraulic drives with throttle and machine control and automatic regulators of change of hydraulic fluid power. Results. It is established that in hydraulic drives with throttle control and pumps with unregulated working volume, throttles on parallel flow and three-wire flow regulators or LS and LUDV modern systems are used; automatic pressure and flow regulators are used with pumps with adjustable displacement; in machine-controlled hydraulic drives through the use of pumps and hydraulic motors with adjustable displacement and hydraulic automation; by energy recovery during operation and bench tests of hydraulic drives; at the design stage of hydraulic drives, when the static analysis is performed in terms of efficiency and dynamic to reduce the loads on the starting modes of operation; and also at designing lay the effective circuit technical decisions promoting energy saving; directly in operation due to high-quality working fluids, heat exchange systems and filtration. Originality. The classification of methods of energy saving in volumetric hydraulic drives of mobile machines is made and examples of application of some means which are planned for introduction in transmissions and the technological equipment of cars for service of aerodromes and planes are resulted. Practical value. The possibility of a rational selection of axial-piston domestic hydraulic machines for the development of hydraulic drives for airfields and aircraft is proven.
Problem. The problem is an integral part of developing the concept of forming a standard range of transport and technological hydrophilic modular means for maintenance of airfields and airplanes. Goal. The goal is development of scientifically sound recommendations for determining the rational parameters of the hydraulic system with automation of control and energy saving during operation of modular vehicles for maintenance of airfields and aircraft, taking into account the potential of domestic engineering and critical imports of units and assemblies. Methodology. The methods include analysis of energy saving methods in hydraulic fluid power of mobile machines according to manufacturers' catalogs and industrial examples taking into account the needs of modular vehicles for maintenance of airfields and aircraft, in particular, taking into account the creation of modern hydraulic devices and circuit solutions in hydraulic drives with throttle and machine control and automatic regulators of change of hydraulic fluid power. Results. It is established that in hydraulic drives with throttle control and pumps with unregulated working volume, throttles on parallel flow and three-wire flow regulators or LS and LUDV modern systems are used; automatic pressure and flow regulators are used with pumps with adjustable displacement; in machine-controlled hydraulic drives through the use of pumps and hydraulic motors with adjustable displacement and hydraulic automation; by energy recovery during operation and bench tests of hydraulic drives; at the design stage of hydraulic drives, when the static analysis is performed in terms of efficiency and dynamic to reduce the loads on the starting modes of operation; and also at designing lay the effective circuit technical decisions promoting energy saving; directly in operation due to high-quality working fluids, heat exchange systems and filtration. Originality. The classification of methods of energy saving in volumetric hydraulic drives of mobile machines is made and examples of application of some means which are planned for introduction in transmissions and the technological equipment of cars for service of aerodromes and planes are resulted. Practical value. The possibility of a rational selection of axial-piston domestic hydraulic machines for the development of hydraulic drives for airfields and aircraft is proven.
Trenchless laying of engineering communications is actively used in all countries of the world. Among the existing methods of formation of wells for the implementation of these technologies, the most popular is the method of ground penetration. The main disadvantage of this method is the poor accuracy of movement of the piercing head in the array. This requires constant adjustments to the trajectory of its movement. This process can be controlled by using a head with an asymmetrical tip and acting on it with translational and rotational motion. The transmission of these movements from the power unit by means of type-setting push rods. Therefore, it is important to choose a trajectory such that the deflection of the bar will be within the permissible stress range. If the bend goes beyond these limits, the rod may break and the puncture process will be interrupted. The conducted studies have established the regularities of the process of puncturing the soil with a head with an asymmetric tip in the form of an inclined flat surface. It has been established that the greatest deviation of the head from the action of the transverse component of the soil resistance force, which occurs when moving such a working body in the soil, will occur at an angle of inclination of the front surface of 25º, and the smallest deviation will occur at an angle of 55º. In addition, it was found that in heavy clay, deflection will occur almost 3 times worse than in a soup and 1.4 times worse than in a loam. It has been experimentally confirmed that at a distance of 10 m the puncture with a head with an inclined forehead surface in sandy loam was 40 mm, and in clay 20 mm. At an angle of inclination of 70º, a constant core of soil compaction is formed and the process of controlling the movement of the head stops.
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