Optimum design of multistep gearbox, since many high-performance power
transmission applications (e.g., automotive, space industry) require compact volume,
has become an important interest area. This design application includes more
complicated problems that are not taken into account while designing single stage
gear drives. Design applications are generally made by trial and error methods
depending on the experience and the intuition of the designer.
In this study, using Visual Basic 6.0, an interactive program is developed for
designing multistep involute standard and nonstandard spur gearbox according to the
American Gear Manufacturers Association (AGMA) Standards 218.01 and 2001-
B88. All the equations for calculating the pitting resistance geometry factor I, and
the bending strength geometry factor J, are valid for external spur gears that are
generated by rack-type tools (rack cutters or hobs). The program is made for twostage
to six-stage gear drives, which are commonly used in the industry.
Compactness of gear pairs and gearbox, and equality of factor of safety against
bending failure is taken as the design objective. By considering the total required
gear ratio, the number of reduction stages is input by the user. Gear ratios of every
stage is distributed to the stages according to the total gear ratio that satisfies the
required precision (from ± / 0.1 to ± / 0.00001 on overall gear ratio) depending on the
user selected constraints (unequal gear ratio for every stage, noninteger gear ratio
e.g.). Dimensional design is determined by considering bending stress, pitting stress,
and involute interference constraints. These steps are carried out iteratively until a
desirable solution is acquired. The necessary parameters for configuration design
such as number of teeth, module, addendum modification coefficient, are selected
from previously determined gear pairs that satisfies the constraints by user
interaction considering the performance criterion from the developed program. The
positions of gears and shafts are determined automatically in order to keep the
volume of gearbox as minimum while satisfying the nonlinear spatial constraints
(center distance constraint for proper meshing of gear pairs, face distance constraint
for proper assembly of pinion and gear having same shaft, gear interference
constraint for preventing interferences between gears, shaft interference constraint
for preventing interferences between gears and shafts) by using DLL (Dynamic Link
Library) technology of Lingo 8.0 optimization software together with Visual Basic
6.0. If shaft interference constraint is removed then cantilevered mounting of gear
pairs would also be possible, otherwise the gears should be mounted between
bearings. Visual output of assembly is made by using Autodesk Inventor 7.0,
automatically by the program.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12606749/index.pdf |
| Date | 01 December 2005 |
| Creators | Ozturk, Fatih Mehmet |
| Contributors | Arikan, Sahir |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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