Experiments on Root Stresses of Helical Gears With Lead Crown and Misalignments

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
M. Hotait ◽  
A. Kahraman
Keyword(s):  
Helical Gear ◽  
Strain Gages ◽  
Helical Gears ◽  
Gear Teeth ◽  
Face Width ◽  
The Face ◽  
Bending Stresses ◽  
Contact Models ◽  
Gear Contact ◽  
Different Levels

In this study, the results of an experimental parametric study of the combined influence of shaft misalignments and gear lead modifications on the load distribution and tooth bending stresses of helical gear pairs are presented. A set of helical gear pairs having various amounts of total lead crown was operated under loaded, low-speed conditions with varying amounts of tightly controlled shaft misalignments. Gear teeth were instrumented through strips of strain gages along the face width of gears at the tooth fillet region at a roll angle that is near the start of the active profile. Variations of root strains along the face width were quantified for different levels of shaft misalignments and gear lead crown. The results presented demonstrate the direct link between the lead crown and gear misalignments as well as the effectiveness of the lead crown in preventing edge loading conditions due to misalignment. The results presented here form a database that should be available for a validation of gear contact models in terms of their ability to simulate misalignments.

An Investigation of the Influence of Shaft Misalignments on Bending Stresses of Helical Gear With Lead Crown

2007 ◽  
Author(s):  
M. A. Hotait ◽  
D. Talbot ◽  
A. Kahraman
Keyword(s):  
Load Distribution ◽  
Helical Gear ◽  
Experimental Results ◽  
Distribution Model ◽  
Strain Gauges ◽  
Gear Teeth ◽  
Face Width ◽  
The Face ◽  
Bending Stresses ◽  
Different Levels

In this study, combined influence of shaft misalignments and gear lead crown on the load distribution and tooth bending stresses is investigated experimentally. A set of helical gear pairs having various amounts of lead crown was tested under loaded, low-speed conditions with varying amounts of tightly-controlled shaft misalignments. Gear teeth were instrumented through strips of strain gauges along the face width of gears at the tooth fillet region near the start of active profile. Variations of root strains along the face width were recorded for different levels of shaft misalignments and gear lead crown. At the end, the experimental results were correlated to the predictions of a gear load distribution model and recommendations were made on how much lead crown is optimal for a given misalignment condition.

scholarly journals Contact Stresses and Bending stresses for Worm & Helical Gear

2019 ◽  
Vol 8 (4) ◽  
pp. 11326-11328
Keyword(s):  
Contact Stress ◽  
Applied Load ◽  
Gear Tooth ◽  
Helical Gear ◽  
Contact Stresses ◽  
Bending Stress ◽  
Surface Strength ◽  
Face Width ◽  
The Face ◽  
Bending Stresses

Surface Strength of the gear tooth depends on the contact stress and the bending stress caused due to the applied load on the tip of its gear tooth. Analysis has become popular in decreasing the failures. Fatigue causes in the root bending stress and Surface indentation causes in the contact stress. Then modified Lewis beam strength is used for bending stress and the AGMA method is used for contact stresses by varying the face width. Analytical results are based on Lewis formula and the theoretical values were calculated by AGMA standard so the results were validated.

Investigation of the Hertzian Stress Distribution on the Surface of the Straight Bevel Gear

2013 ◽  
Vol 307 ◽  
pp. 304-307 ◽  
Author(s):  
Aref Bahramighahnavieh ◽  
Peiman Mosaddegh ◽  
Saleh Akbarzadeh
Keyword(s):  
Stress Distribution ◽  
Spur Gear ◽  
Bevel Gear ◽  
Gear Teeth ◽  
Straight Bevel Gear ◽  
Face Width ◽  
The Face ◽  
Simulation Results ◽  
Abaqus Software ◽  
Good Agreement

In this paper, a model has been developed for calculating the Hertzian stress distribution of straight bevel gear. One pair of straight bevel gear teeth replaced with multiple pairs of spur gear teeth by using Tredgold approximation. The transmitted load and radii of curvature are evaluated and used to determine the stress distribution. The results show that these stresses are constant along the face width of tooth. Moreover, the magnitude of theses stresses are in good agreement with the simulation results using commercial ABAQUS software

Tooth Root Stresses of Helical Gear Pairs With Unequal and Offset Face Widths

2011 ◽  
Author(s):  
Carlos H. Wink
Keyword(s):  
Load Distribution ◽  
Element Model ◽  
Helical Gear ◽  
The Other ◽  
Gear Pair ◽  
Tooth Root ◽  
Pair Member ◽  
Face Width ◽  
The Face ◽  
Root Stress

In this study, tooth root stresses of helical gear pairs with different combinations of face width increase and offsets were analyzed. Contact face width was kept constant. The variables studied were face width and gear faces offset. The well-known LDP – Load Distribution Program was used to calculate tooth root stresses using a finite element model. The results presented show that the face width increase and offset have a significant influence on tooth root stresses. In some cases, increasing face width of one gear pair member resulted in significant increase of tooth root stress of the other member. For gear pairs with unequal and offset face widths, tooth root stresses were mostly affected when face widths were increased to the same direction of the contact line travel direction.

Calculation of Wobble From Lead Inspection Data of Gear Teeth With Modifications

1998 ◽  
Author(s):  
Xiaogen Su ◽  
Donald R. Houser
Keyword(s):  
Satisfactory Result ◽  
Spur Gear ◽  
Helical Gear ◽  
Spur Gears ◽  
Helical Gears ◽  
Gear Teeth ◽  
Inspection Data

Abstract The effect of the reference misalignment including eccentricity and wobble on profile and lead inspection traces is discussed. The relative slopes of the lead traces induced by wobble are used to calculate the magnitude of the wobble. The deviation caused by the wobble is removed from the lead inspection results. This method is theoretically ‘exact’ for spur gears and is approximate for helical gears. Real measurement examples show this method produces a good result with a spur gear and a satisfactory result with a helical gear.

Using variable modulus to modify a rack cutter and generate a gear pair

2022 ◽  
pp. 095440622110617
Author(s):  
Yang Hsueh-Cheng ◽  
Zhong-Wei Huang
Keyword(s):  
Helical Gear ◽  
Tooth Surface ◽  
Gear Pair ◽  
Tooth Contact Analysis ◽  
Parabolic Profile ◽  
Face Width ◽  
Variable Modulus ◽  
The Face ◽  
Helical Gear Pair ◽  
Assembly Error

In this paper, two normal imaginary helical rack cutters were first established. One of these cutters is a skewed-rack cutter with an asymmetrical straight edge. The other is a rack cutter with an asymmetric parabolic profile. Second, the gear’s tooth surface of the asymmetric parabolic rack cutter is modified to be barrel-shaped based on a variable modulus. The tooth thickness of the gear is gradually reduced along the face width of the tooth from the middle of the tooth surface. Then the coordinate relationship between the gears’ blanks and the imaginary helical rack cutters was established. Through the differential geometry, crowned and uncrowned helical gear pairs were generated. Because of human factors, when the gear pair is installed, it is easy to cause the gear pair edge contact. It is necessary to add artificial assembly error settings through the tooth contact analysis to investigate the kinematic errors and contact conditions of the crowned and uncrowned helical gear pair. The mathematical models and analysis methods proposed for the crowned imaginary rack cutter using variable modulus should be useful for the design and production of double crowned helical gears with asymmetric parabolic teeth.

CAD and Optimization of Spur and Helical Gear Sets

1996 ◽  
Author(s):  
Sayed M. Metwalli ◽  
Ehab A. El Danaf
Keyword(s):  
Computer Aided Design ◽  
Full Range ◽  
Optimization Techniques ◽  
Design Stage ◽  
Helical Gears ◽  
Face Width ◽  
Optimum Parameters ◽  
Number Of Teeth ◽  
Wide Range ◽  
The Face

Abstract The present work is an application of Computer Aided Design and optimization techniques to solve the problem of designing a pair of gears. The CAD programs have the initial freedom to change the design variables: the module, the number of teeth, the face width, and the material through a data base display, and a full detailed design stage that applies the AGMA bending and contact number checking criteria, and the bending fatigue strength and the surface endurance strength criteria. Other programs are also linked to optimize spur gears under the objective of minimizing the volume. The design vector is taken to be the module, the number of teeth, and the face width, with the interaction between bending and contact stress constraints. These programs were utilized to study the behavior of the optimum parameters for a full range of cases. Charts of the optimum results are plotted. For optimizing helical gears, the design vector is taken as the module, the number of teeth, the face width, and the helix angle. A comparison is made between values of the objective function and optimum parameters for spur and helical gears for a wide range of cases. A comparison is also made of the results with other previous works of optimization and proved that the approach presented here gives better optimum results for the same loading case.

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