Prof. J. Walter - Informationstechnik, Mikrocomputertechnik, Digitale Medien Vorwort
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Sommersemester 2019

Vorwort zum Projekt

Ensuring the mechanical strength, efficiency and performance of the teeth in the gears has long been a field of discussion and debate among scientists.

In fact, new types of faults have been studied and the optimization tendencies have a negative side of the coin as the teeth of the wheels do not change the operating conditions for which they were designed. The use of optimization decreases the safety margins and attention must be paid to ensure the proper functioning of the products.

José I. Pedrero [9] in this article proposes a method to study the influence of the number of teeth and the correction, in the resistance to the flexion, doing a regression and obtains analytical expressions in the calculation of straight cylindrical gears and helical profile involute.

Alfonso [10] carried out a study of the flexural behavior of cylindrical gears of involute profile, in the models proposed by the AGMA and ISO norms and the generalization of the expressions of the calculation methods. In addition, he developed a model based on the geometry of the tooth in the section normal to the contact line, and developed the corresponding calculation method; now the results depend largely on the values of the constraints, so that, if the admissible bending tension has a high value, the optimal solution has a high number of teeth and if the admissible bending tension is low, the optimal solution moves towards fewer teeth.

In this article Pedrero [11] performs an analysis in the lubrication of elastohidrodynamic theories, where geometric factors vary to obtain a favorable change in the specific thickness of the lubricant film and thus increase the resistance to wear and seizing, only that the variables of these faults are common, that is, when you make the variations to increase the resistance in one, it increases in the other.

In this work, Moya [12] analyzes the influence of the modifications of the tooth profile, which are achieved with the correction of the tooth on the resistance of the tooth to the bite. The values of the height correction coefficient that guarantee the maximum resistance to the pit are determined, in addition the values of the angular correction coefficient are determined for the resistance to the bite, breakage and wear.

In the article Gonzalo [13] presents a procedure that allows to determine a value of reference useful life foreseeing the breakage by fatigue of the steel teeth in wheels of cylindrical gears of parallel axes and external contact. The procedure is based on considering the resistance to pitting and bending of the teeth in cylindrical gears according to AGMA standard 2101-D04 [14] aimed at calculating the load capacity of cylindrical gears.

Designers face difficult decisions quite frequently because they must choose between several possibilities, called alternatives, the set of which constitutes the so-called set of choice. To choose in this set the decision maker has different points of view, called "criteria". These criteria are, at least partially, contradictory in the sense that, if the designer adopts one of these points of view, for example, cost minimization will not choose the same alternative as if it is based on another criterion, for example, the of better performance. One of the advantages of the simulation of the pair of gears in a test bench under the action of real loads is that at the end of the test a clear answer is obtained to the problem of which design criterion to select because the result of the physical behavior of the machine elements under study.

There is another option and it is that once this result is obtained in the test bench it is possible to optimize several objective functions at the same time, multicriterial design, it does not result in finding an optimum for each function, but rather in proposing a set of points in those that each objective function contributes to reach a good total fitness, which will be established and evaluated by the designer. The multicriteria modeling provides the designer with a freedom of judgment that is hidden by the monocriterion modeling. Multicriteria modeling is thus much more realistic since it considers the restrictions for what they really are, namely, elements of the decision, that is, criteria [15].

In this work, a prototype test bench for gears is proposed based on several criteria taken from existing problems in the industry, and the multiple applications that gears have today. So it is proposed that it be of universal type, ie of variable configuration so that the structure can be adapted to any type of gear, for this four motors are needed, an electromagnetic brake is also proposed that makes it possible to test stable loads or variants in the time in both cases its effect is instantaneous and finally a cooling system for both systems and to test different types of lubricants and their effect on the system.

  Mit Unterstützung von Prof. J. Walter Sommersemester 2019