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.
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