One of the assumptions made during the modernization process of diesel shunting locomotives is the replacement of a diesel traction motor with a DC generator with an electric asynchronous traction motor. The article aimed to develop a method of selecting energy-efficient parameters of an asynchronous electric traction motor for diesel shunting locomotives, which will ensure that its operating energy efficiency will be as high as possible. The method was verified on the example of a locomotive series ChME3 (ЧMЭ3, ČME3, ČKD S200). It has been found that using a traction asynchronous electric drive on a ChME3 locomotive, its efficiency increases in comparison with DC electric motors by 3–5% under the long-term operation modes and by 7–10% during locomotive operation with traction at the adhesion limit. Using a new traction gearbox with a higher gear ratio expands the speed range in which the asynchronous traction drive operates with a high-efficiency factor. It is effective to use a traction asynchronous electric drive to modernize ChME3 diesel locomotives in case of their use under the modes requiring the implementation of maximum traction forces at low speeds. A further increase in the efficiency of the traction asynchronous electric drive is possible based on the optimal design of the wheel-motor unit and the asynchronous traction electric drive.

No abstract

No abstract

The subject matter of the research is issues related to the optimization of the technology for reconditioning large-size high precision gear rims of the drives of mining complexes, mine lifting equipment, heavy vehicles; these issues are a perspective trend for reducing the cost of reconditioning and operation of expensive unique equipment. The goal is to ensure intensifying production processes, increasing workloads and speeds, reducing the deterioration of high precision gear rims. The objective is to develop a new technology to optimize reconditioning large high precision gear rims. To achieve this, the following method is suggested -to machine gear rims after they have been surfaced by pre-milling with special hob cutters with a prominence and by final machining the teeth with special cutters equipped with hardmetal inserts that process teeth along the line of engagement, which does not require making full-length cutting teeth and increases the quality of machining, the durability of hardmetal milling cutters. The process of reconditioning of large high precision gear rims is a resource-saving technology, as compared with manufacturing new parts, this technology considerably reduces the cost of materials for manufacturing, decreases a number of process steps, reduces the cost of machining equipment, tools, cutting and measuring instruments. The smooth operation of a gear train can be ensured only at a constant gear ratio but due to manufacturing and operational errors, the gear ratio is not constant at every time, which intensify the deterioration of large high precision gear rims. The following results are obtained. The possibility and practicability of using hob cutters with a prominence (m = 20-28 mm) while rough cutting the worn and reconditioned large gear rims was proved. To obtain the necessary durability of rough milling cutters, it is recommended that the prominence angle be set within 8-10°. The use of hardmetal hob cutters for finishing makes it possible to increase the performance rate by 2 to 3 times as compared to high-speed cutters of other designs and to obtain the necessary quality and precision of manufacturing worn and reconditioned large gear rims. Conclusions. The technology for the optimization of reconditioning large high precision gear rims with the use of special and universal hardmetal single-and double-flute cutters that have both re-sharpened cutting elements and disposable rotary tools was developed and introduced.Keywords: new optimization technology, reconditioning large gear rims, high precision, hob cutters with a protuberance, special cutters, machining tooth along the line of engagement, improving the quality of machining.

The global trend of improving vehicle and traction transmissions is associated with the use of robotic preselector gearboxes, an important component of which is the friction clutch. The review of existing designs and analysis of clutch development concepts allows determining the directions of their improvement, in particular, the improvement of dry double clutches, which is the subject of research in this paper. A significant disadvantage of existing dual-clutch designs is the use of additional special (mostly hydraulic or combined) systems for on-off friction pairs, so the structural cost and energy costs for control are increased, and the design, maintenance, and repair are complicated. The proposed design of the drive to control the original dry dual-clutch involves a lever mechanism with the use of rotary stops, which are made in the form of mobile carriages with rollers, this provides switching clutches in a short time and actually without interruption of power flow, so the acceleration dynamics of vehicles will be improved, the clutch design will be simplified and energy consumption for its control during the start and gear shifting will be reduced. The mathematical model of the proposed clutch drive on the basis of which the control mechanism operation is simulated and influence of its design parameters on operational indicators of the clutch drive, in particular, on kinematic characteristics of the drive, ranges of kinematic and power gear ratios, the power interaction of the mechanism links, the power of the actuator when each clutch is turning on. It is established that the switching of clutches requires less energy, the movement of the mechanism elements is different, and the compression force of the friction pairs when starting the first and second clutches is different. The simulation results confirm that the proposed original lever design of the clutch control mechanism is effective. The obtained results allow us to reasonably determine the parameters of a clutch, but the choice of optimal-rational parameters of its control mechanism requires further research, for which appropriate methods, search algorithms, and their software implementation have been developed.