Achieving the Stakeholders Equilibrium in Vocational Education for the Digital Economy

This chapter is aimed at searching for a sophisticated equilibrium in vocational education in the digital economy times between its key stakeholders or, in other words, its gear wheels, which are the government, enterprise, university, and the people. The authors focus on the programs designed in the light of the digital economy. As emerging economies face bigger challenges, the chapter is about such countries, in particular about Russia as one of them which has a big state's stake. First, the chapter lays the groundwork to the instrumentalist vision of education for the stakeholders' relations and covers a historical background to the political economy in Russia. Secondly, the authors discuss the CVET key stakeholders' motives, capacities, and barriers. The authors demonstrate the spots where these wheels mismatch. Third, online learning is presented as a possible solution for at least some of the mismatches, such as the lack of the specialists and practice-based constituents in the learning program, the system bureaucracy, obsolete teaching approach, and rigid learning trajectories.

Profiling of a shaped worm cutter for shaping gears with non-involute tooth profile

Of the mechanical transmissions used in mechanical engineering, the most common are gears with an involute profile of the teeth flanks. Gears made up of such wheels have a number of advantages, but they also have a number of significant disadvantages. Therefore jne of the current trends is the study of gears with a complex non-involute profile of the teeth flank which have advantages over involute gears in a number of applications, as well as the development of tools for their processing. There are two ways of gear teeth cutting: the copying method and the rolling-in method. The rolling-in method has advantages. The profile of the tool working by the rolling-in method does not depend on the number of teeth of the gear being cut, therefore, the same tool can be used to cut gears with any number of teeth. The accuracy of a gear made by the rolling-in method is significantly higher than the accuracy of a gear made by the copying method. This is primarily due to the continuity of the rolling-in process. When cutting teeth by the rolling method, the tooth surface is formed as a result of processing with a tool, the cutting edges of which are the tooth profile of the mating rack or the tooth profile of the mating gear, and during processing the tool and the workpiece form a mating gear pair. The most common gear cutting tool is the hob cutter. For the machining of gear wheels with a non-involute tooth profile widely used in industry equipment is used. One of the options for a rolling gear cutting tool for shaping gear wheels with a non-involute tooth profile can be a shaped worm cutter. The article describes the method of profiling of the cutting part of shaped hob cutter for machining of gear wheels with normal accuracy. To solve the problem the unified mathematical base – the apparatus of multiparameter mappings of space – the unified structure of mappings for gears and a compact set of unified operators, parameters and functional connections is used.

MODELING AND ANALYSIS OF PARAMETRIC OPTIMIZATION OF THE MASS OF A CLOSED PLANETARY MECHANISM FORMED BY TWO SIMPLE PLANETARY MECHANISMS OF JAMES

The mathematical model of estimation of a design mass of the closed planetary mechanism formed from two simple planetary mechanisms of James (mechanism of type ), taking into account their structural diagrams and design constraints, determined by the conditions of contact and bending strengths of external gearing of sun gears and satellites, is offered. A model is a dimensionless function (analogue of mass) of two variables – transmission relations of simple planetary mechanisms, and set of numerical parameters. As parameters of analogue of mass coefficients are chosen, characterizing the models of mass of gear wheels and carriers, structural and strength limitations of the external gearing of simple planetary mechanisms of the type , and also structure of these mechanisms. In the program Mathcad differential properties of the offered model and influence on position of minimum of analogue of mass are investigational depending on the numerical values of his parameters. Documents of the Mathcad program are presented that implement computer modeling of algorithms for parametric optimization of mass closed planetary mechanism, where the function of the analogue of the mass of the given mechanism is used as the objective function. A comparative analysis of minimizing the design mass of two kinematic schemes of planetary mechanisms is considered – closed planetary mechanism and in-line planetary of the type . Keywords: simple planetary mechanism of James, simple planetary mechanism type ; closed planetary mechanism; in-line planetary mechanism; mass of closed planetary mechanism; contact strength of gearing; bending strength of gearing; parametric optimization; parametric optimization of mass of planetary mechanism

PROCESSING OF HARDENED CYLINDRICAL GEAR WHEELS OF THE CUTTING GEARBOX OF THE COMBINE UKD 200-500

The article discusses the latest developments of unique technological methods of gear milling of cylindrical gears for preliminary blade gear processing of hardened cylindrical gears of the cutting reducer of the UKD200-500 coal mining harvester for the final gear grinding of gear teeth with modulus m = 16 mm, with hardness HRC 56 ... 62. The peculiarity of the design of special hob cutters is that a circle passing through the lower boundary points of the involute is used as the palloid of the machine gearing of the tool and part. Pre-cutting the teeth of hardened wheels with carbide milling cutters allows you to remove the main allowance for the final gear grinding.

MEANS, STANDS AND MACHINES FOR TESTING GEAR WHEELS AND GEAR TRAINS OF HELICOPTER REDUCTION TRAINS

The production and repair of such high-tech and important products as helicopters‟ reduction trains is impossible without comprehensive testing of these products, starting with the manufacture of their individual parts and assemblies and ending with the delivery of reduction trains to the customer. Various means for testing of gear wheels‟ rims and gear trains of helicopter‟s reduction trains, which have found application in testing equipment, are presented. Devices, testers, stands and machines for various tests are considered in order to control the characteristics of gear trains of aviation reduction trains after certain periods of their operation and repair, aimed at achieving better performance during further operation. The considered traditional metrological means of control of gear rims, gear measuring machines and complexes, some stands and machines for testing of reduction trains, pulse controllers and roll machines give an idea of various methods and means of control of gear wheels and gear trains of helicopters‟ reduction trains. The main method of experimental research of gear trains of reducers is stand tests both on movable gear wheels and on roll machines. Until recently, the most common method for monitoring and diagnosing gear trains has been vibrography, however, existing techniques do not give an accurate picture of the train condition, especially the contact surface of the teeth. During the operation of the gear train as a part of the helicopter‟s reduction train, signals from other sources (rotors, blades, shafts, bearings) are superimposed on the vibration signal generated by the gear train which significantly complicates the extraction and processing of the desired vibration signal. One of the most effective methods for monitoring and diagnosing the technical condition of kinematic chains of different complexity, which includes gear trains of helicopters„ reducers is kinematometry. The disadvantage of traditional kinematometry is the need to use high-precision sensors for the frequency and phase of the rotor rotation. Control of vibration from the early 1990s to the present time is the most advanced control, the means and methods of which are well developed in the aviation industry.

Diagnostics of the technical condition and predic-tion of accident-free guaranteed operating time of heavily loaded machines gear wheels

Problem. This article highlights the current state of diagnostics of gears on the level of accumulated fatigue damage in operation. The generalization of the known information on determination of a technical condition of separate gear wheels, especially with big modules (m> 20 mm), allows to outline prospects of development of such diagnostics of a technical condition of gear wheels directly in the course of operation. Goal. The goal of this study is to develop an algorithm for diagnosing the technical condition and forecasting a fault-free operation of the gears of heavy-duty machines. Methodology. The least squares method and the confidence interval method are used to predict accident-free guaranteed gear operation. Results. A procedure for diagnosing the technical condition of gears by measuring the hardness of the metal has been developed, which includes five main stages: selection of the device; choice of measurement scheme; selection of the number of measurements, number and relative position of measuring points; development of a design of a template for measurements; development of a device for fastening templates. When determining the accident-free guaranteed operating time on the basis of several criteria of the limit state, the final decision is made on the criterion that determines the minimum term. Originality. The method of forecasting accident-free guaranteed operating time of gears is chosen taking into account the stages of running-in and stable in linear function accumulation of damage in operation. Practical value. The use of the developed procedure for diagnosing the technical condition of the gears of gearboxes of heavy-duty machines will significantly increase the efficiency of their operation due to the transition from scheduled preventive maintenance to maintenance according to the actual technical condition.

Learning an Optimal Operational Strategy for Service Life Extension of Gear Wheels with Double Deep Q Networks

One failure mechanism of gear wheels is pitting. If the gear wheel is case hardened, pitting degradation dominates normally at one tooth only. All the other teeth are still intact at the standardized end of life criterion of 4 % pitting area based on the total tooth area. Using an operational strategy that was developed at the Institute of Machine Components, the service life of gear wheels can be extended by a local stress reduction at the weakest tooth. This is accomplished by applying an adapted torque at the transmission input that shifts a minimum torque in the area of the pre-damaged, and thus, weakest tooth. Consequently, all remaining teeth with higher load bearing capacity are subjected to higher torque. Prerequisite for the described theoretical operational strategy is knowledge on pitting-size and -position. The detection of these properties in operation is not state of the art yet. In this work, only the gearbox vibration signal is known without explicit knowledge about the inside pitting. So the challenge is to determine the health for each individual tooth and to choose an optimal adapted torque based on this. This is especially difficult due to differing growth rates of pittings on one individual gear wheel. Hence, different pittings dominate over the service life, which results in the need of a continuous optimization of the torque control. Algorithms of Reinforcement Learning (RL) are particularly suitable for this challenge. In this branch of Machine Learning (ML), an agent interacts inside an environment and learns by getting rewards for taking actions at given states. In this study, the environment is a gearbox-simulation-model, the state is the current vibration signal, and the action is the chosen adapted torque. Thus, it is possible to let the algorithm learn the whole operational strategy, from online failure detection to an adapted torque at the transmission input. The results of this study show the theoretical feasibility of the operational strategy using Double Deep Q Networks as the RL Algorithm. The algorithm is able to learn a suitable reaction to pittings that increase linearly or progressively at an early stage and therefore delays their growth within the defined limits. Thus, the lifetime of the gearbox is extended while maintaining the same total power of the gearbox. As an outlook, the results will be examined for their sensitivity on several influencing factors in a further study. The wider view is to use this simulation on a test rig and validate the results.

Constructional design of the body shape of large gear wheels

The development of modern machines and means of production is characterized by ever-increasing performance parameters with decreasing equipment weight. When designing large gears, it is also necessary to consider the influence of the body shape of the gear wheel. The body shape of gear wheel must meet the basic requirements of stiffness and strength with the lightest possible construction of the gear wheel body. The work is focused on large gears, made with relief. Such gears can be forged, cast, or made by welding. The shape of the gear wheel body depends on several factors such as the size of the wheel, the material, the method of manufacture or use. The paper provides an overview of the body shapes used by large spur gears. These body shapes of spur gears will be the subject of further research, where suitability will be assessed based on stiffness of teeth and wheel weight.

Modeling Deformation of Spur Gear

In The work considers 11 types of gears, features of their design and application. Analysis of gears designs is carried out, since shape of teeth directly affects process of teeth gearing, and this, in turn, affects load, which causes deformation of elements. 3D model of spur gear was created in ANSYS system. The work was limited by analyzing problem from point of view of gear wheels’ deformation, which were made of 40L carbon steel and carbon composite material. As a result, finite element modeling and analysis of gears using ANSYS system was carried out.

Increasing the safety against scuffing of additive manufactured gear wheels by internal cooling channels

The layer-by-layer principle of the additive manufacturing (AM) technology of Laser-Powder-Bed-Fusion (LPBF) creates new opportunities in the design and manufacturing of efficient gear components. For example, integrating a cooling system can increase the safety against scuffing or reduce the amount of required lubrication and thus the splashing losses. Quenched and tempered steels or case-hardened steels are commonly used in the fabrication of gear components. However, the availability of these alloys for LPBF processing is still limited. The development of suitable LPBF metal gears (with a Gear Research Centre (FZG) type A geometry) out of quenched and tempered 30CrNiMo8 steel with internal cooling channels shows the possibility of significantly increasing the safety factor against scuffing. This work includes the development of a suitable cooling strategy, material development, the setup of a suitable test infrastructure and the analysis of the LPBF gears tested for scuffing.