Computer-Aided Optimal Gear Design

1992 ◽  
Author(s):  
G. C. Andrews ◽  
J. D. Argent
Keyword(s):  
Optimum Design ◽  
Material Properties ◽  
Bending Strength ◽  
Speed Ratio ◽  
Tooth Size ◽  
Spur Gears ◽  
Distance Method ◽  
Gear Design ◽  
Computer Aided ◽  
Center Distance

Abstract Gear-sets designed using standard tooth profiles are rarely optimum strength designs, where “optimum strength” is defined as the maximum tooth bending strength for minimum tooth numbers and tooth size. However, standard tooth profiles are widely used because of the difficulty of determining the amount of hob (or rack) “offset” necessary to cut optimum strength non-standard gears. Also, stresses are not easily calculated for non-standard tooth profiles since geometry factors (I and J) are not tabulated. This paper describes a computer-aided method for obtaining optimum strength designs of spur gears, through iterative strength calculations. Two common cases are considered in which a non-standard gear-set is to replace a standard gear-set with the same center distance. When the speed ratio must be rigidly maintained, the “long and short addendum method” can be used; when minor variations in speed ratio are permissible, the “non-standard center distance” method can be used and much larger increases in strength can be achieved. The methods are illustrated by a numerical example. Increases of strength in the range of 10 to 20 percent are typical when standard gears-sets are replaced by non-standard gears with the same center distance, assuming material properties remain constant. The procedure for estimating the hob offsets which yield optimum design is simple and novel, and has proved efficient in obtaining convergence in a few iterations of the optimization process.

Probabilistic Optimum Design of Compact Spur Gear Sets

1995 ◽  
Author(s):  
Chinyere Onwubiko ◽  
Landon Onyebueke ◽  
Feng C. Chen
Keyword(s):  
Optimum Design ◽  
Material Properties ◽  
Probabilistic Method ◽  
Spur Gear ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Deterministic Method ◽  
Wide Range ◽  
Comparison Of The Results ◽  
Center Distance

Abstract Several methods have been proposed in the past for optimum design of spur gears. These methods have utilized deterministic design optimization techniques to obtain what could be considered satisfactory design parameters. At least two problems arise with the results of the deterministic approach; the inability to deal with uncertainties in material properties and over conservative design. On the other hand, probabilistic analysis methodology seeks to account for the uncertainties in material properties, loading conditions and disparate failure models. This paper discusses the application of probabilistic design methodology to the design of compact gear set. This is done by minimizing the gear center distance while constrained by the allowable surface pressure and bending stress. A comparison of the results of compact gear design using both deterministic and probabilistic methodologies is presented. The results indicate that deterministic method though satisfactory does not provide the designer enough information to make vast design decisions. The deterministic method provides only one value of the center distance while the probabilistic method provides the designer a range of choices. In fact, a designer is provided a wide range of design options depending on a desired level of reliability.

The Synthesis of Tooth Profile Shapes and Spur Gears of High Load Capacity

1970 ◽  
Vol 92 (3) ◽  
pp. 543-551 ◽  
Author(s):  
A. O. Lebeck ◽  
E. I. Radzimovsky
Keyword(s):  
Bending Strength ◽  
Load Capacity ◽  
High Capacity ◽  
High Hardness ◽  
Spur Gear ◽  
Speed Ratio ◽  
Spur Gears ◽  
Gear Pair ◽  
Contact Ratio ◽  
High Load Capacity

In this work a method is presented for the synthesis of high capacity noninvolute spur gears and tooth profiles. Two gear capacity criteria are used in the synthesis: (1) the capacity based on maximum allowable Hertz stress and (2) the capacity based on the bending strength of the tooth. These capacity criteria are related to a generalized noninvolute gear geometry which includes the factors number of teeth and contact ratio. It was found that there are certain optimal relationships which exist among the noninvolute parameters which lead to a solution, for a maximum capacity noninvolute gear pair. For a speed ratio of one to five it was found that a significant capacity advantage exists for the synthesized noninvolute gear pair (compared to a 20-deg involute spur gear pair) for moderate as well as high hardness values. For a speed ratio of one to one a capacity advantage was found for moderate hardness but the advantage decreased significantly for high hardness.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

Using Constraint Management Techniques to Design Spur and Helical Gears

1992 ◽  
Author(s):  
Rajiv Agrawal ◽  
Natarajan Sridhar ◽  
Gary L. Kinzel
Keyword(s):  
Mathematical Formulation ◽  
Spur Gears ◽  
Helical Gears ◽  
General Design ◽  
Gear Design ◽  
Constraint Management ◽  
Management Techniques

Abstract This paper presents the use of constraint management techniques to design spur and helical gears. The constraints for gear design are presented in a declarative manner such that they can be incorporated in a general Design Shell environment. A declarative representation allows the designer to experiment with a number of different designs and perform “what-if” scenarios. Since spur gears form a subset of helical gears, the mathematical formulation is presented for helical gears only. The analysis of helical gears is based on the AGMA/ANSI Standard 2001-B88.

Computer-Aided Gear Product Realization

2018 ◽  
Author(s):  
Alireza Yazdanshenas ◽  
Emilli Morrison ◽  
Chung-Hyun Goh ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Computer Aided Design ◽  
Interaction Analysis ◽  
Gear Tooth ◽  
Integrated Design ◽  
System Level ◽  
Trial And Error ◽  
Stress Concentrations ◽  
Element Analysis ◽  
Gear Design ◽  
Computer Aided

To save time and resources, many are making the transition to developing their ideas virtually. Computer-aided gear production realization is becoming more and more desired in the industry. To produce gears with custom qualities, such as material, weight and shape, the trial and error approach has yielded the best results. However, trial and error is costly and time consuming. The computer-aided integrated design and manufacturing approach is intended to resolve these drawbacks. A simple one stage reduction spur gearbox is used as an example in a case study. First, the gear geometry is developed using computer aided design (CAD) modeling. Next, using MATLAB/Simulink, the gear assembly is connected virtually to other subsystems for system expectations and interaction analysis. Finally, using finite element analysis (FEA) tools such as ABAQUS, a dynamic FEA of the gear integration is completed to analyze the stress concentrations and gear tooth failures. Through this method of virtual gear design, customized dimensions and specifications of gears for satisfying system-level requirements can be developed, thereby saving time and manufacturing costs for any custom gear design request.

Using Dynamic Analysis for Compact Gear Design

1998 ◽  
Author(s):  
Ping-Hsun Lin ◽  
Hsiang Hsi Lin ◽  
Fred B. Oswald ◽  
Dennis P. Townsend
Keyword(s):  
Dynamic Response ◽  
Bending Strength ◽  
Three Dimensional ◽  
Spur Gear ◽  
Dynamic Factor ◽  
Operating Speed ◽  
Gear Design ◽  
Dynamic Factors ◽  
Speed Range ◽  
Response Change

Abstract This paper presents procedures for designing compact spur gear sets with the objective of minimizing the gear size. The allowable tooth stress and dynamic response are incorporated in the process to obtain a feasible design region. Various dynamic rating factors were investigated and evaluated. The constraints of contact stress limits and involute interference combined with the tooth bending strength provide the main criteria for this investigation. A three-dimensional design space involving the gear size, diametral pitch, and operating speed was developed to illustrate the optimal design of spur gear pairs. The study performed here indicates that as gears operate over a range of speeds, variations in the dynamic response change the required gear size in a trend that parallels the dynamic factor. The dynamic factors are strongly affected by the system natural frequencies. The peak values of the dynamic factor within the operating speed range significantly influence the optimal gear designs. The refined dynamic factor introduced in this study yields more compact designs than AGMA dynamic factors.

Gear root bending strength: a comparison between Single Tooth Bending Fatigue Tests and meshing gears

2021 ◽  
pp. 1-17
Author(s):  
Luca Bonaiti ◽  
Ahmed Bayoumi Mahmoud Bayoumi ◽  
Franco Concli ◽  
Francesco Rosa ◽  
Carlo Gorla
Keyword(s):  
Failure Modes ◽  
Bending Strength ◽  
Gear Tooth ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Gear Design ◽  
Single Tooth ◽  
Actual Strength ◽  
Meshing Gears ◽  
Definition Of

Abstract Gear tooth breakage due to bending fatigue is one of the most dangerous failure modes of gears. Therefore, the precise definition of tooth bending strength is of utmost importance in gear design. Single Tooth Bending Fatigue (STBF) tests are usually used to study this failure mode, since they allow to test gears, realized and finished with the actual industrial processes. Nevertheless, STBF tests do not reproduce exactly the loading conditions of meshing gears. The load is applied in a pre-determined position, while in meshing gears it moves along the active flank; all the teeth can be tested and have the same importance, while the actual strength of a meshing gear, practically, is strongly influenced by the strength of the weakest tooth of the gear. These differences have to be (and obviously are) taken into account when using the results of STBF tests to design gear sets. The aim of this paper is to investigate in detail the first aspect, i.e. the role of the differences between two tooth root stress histories. In particular, this paper presents a methodology based on high-cycle multi-axial fatigue criteria in order to translate STBF test data to the real working condition; residual stresses are also taken into account

Sign in / Sign up

Export Citation Format

Share Document