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.

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.

Contact Stress Analysis of a Helical Gear

2015 ◽  
Vol 766-767 ◽  
pp. 1070-1075 ◽  
Author(s):  
R. Devaraj
Keyword(s):  
Stress Analysis ◽  
Contact Stress ◽  
Gear Tooth ◽  
Element Model ◽  
Helix Angle ◽  
Helical Gear ◽  
Bending Stress ◽  
Helical Gears ◽  
Modeling Software ◽  
Main Factors

The main factors that cause the failure of gears are the bending stress and contact stress of the gear tooth. Out of these, failure of gears due to contact stress is high compared to bending stress. Stress analysis has been a key area of research to minimize failure and optimize design. This paper gives a finite element model for introspection of the stresses in the tooth during the meshing of gears. Specifically, helix angle is important for helical gears. Using modeling software, 3-D models for different helix angles in helical gears were generated, and the simulation was performed using ANSYS 12.0 to estimate the contact stress. The Hertz equation and AGMA standard was used to calculate the contact stress. The results of the theoretical contact stress values, using Hertz and AGMA are compared with the stress values from the FEA for different helix angles and the results are tabulated and discussed.

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.

Modification of an Involute Gearing and Its Effect on a Loading Capacity

2007 ◽  
Author(s):  
Zdenek Dejl ◽  
Vladimir Moravec
Keyword(s):  
Contact Stress ◽  
Input Data ◽  
Experimental Methods ◽  
Loading Capacity ◽  
Separate Part ◽  
Face Width ◽  
Lifetime Test ◽  
The Face ◽  
Involute Gears

A modification of an involute gearing is presented by a modification of an involute and a longitudinal modification along the face width. In the contribution both of the modifications are presented and theoretical and practical methods for determination of their parameters are shown. Experimental methods of setting up of input data for design of modifications are brought in then. These data are prepared on the basis of measuring of deformations of gearwheels bodies, shafts and shafts supports. An attention is given to the influence on a size and position of a zone of contact of meshing teeth. A separate part deals with the appreciation of an influence of modification on a size of a noise and vibrations of involute gears. As far as a loading capacity of modified involute gearings, the attention is first given to the loading capacity in a contact stress between teeth faces. The comparison is made between loading capacity of an involute gearing with no modification and a gearing modified by various types of modifications. This comparison is made both by using a FEM and by experiment. Experiment is based on lifetime test of these gearing.

Investigating the effect of helix angle and pressure angle on bending stress in helical gear under dynamic state

2018 ◽  
Vol 15 (4) ◽  
pp. 478-488
Author(s):  
Prashant Jaysing Patil ◽  
Maharudra Patil ◽  
Krishnakumar Joshi
Keyword(s):  
Gear Tooth ◽  
Helix Angle ◽  
Helical Gear ◽  
Dynamic State ◽  
Load Carrying Capacity ◽  
Bending Stress ◽  
Content Type ◽  
Gear Design ◽  
Pressure Angle ◽  
Load Carrying

Purpose The aim of this paper is to study the effect of pressure angle and helix angle on bending stress at the root of helical gear tooth under dynamic state. Gear design is a highly complex process. The consistent demand to build low-cost, quieter and efficient machinery has resulted in a gradual change in gear design. Gear parameters such as pressure angle, helix angle, etc. affect the load-carrying capacity of gear teeth. Adequate load-carrying capacity of a gear is a prime requirement. The failure at the critical section because of bending stress is an unavoidable phenomenon. Besides this fact, the extent of these failures can be reduced by a proper gear design. The stresses produced under dynamic loading conditions in machine member differ considerably from those produced under static loading. Design/methodology/approach The present work is intended to study the effect of pressure angle and helix angle on the bending stress at the root of helical gear tooth under dynamic state. The photostress method has been used as experimental methods. Theoretical analysis was carried out by velocity factor method and Spott’s equation. LS DYNA has been used for finite element (FE) analysis. Findings The results show that experimental method gives a bending stress value that is closer to the true value, and bending stress varies with pressure angle and helix angle. The photostress technique gives clear knowledge of stress pattern at root of tooth. Originality/value The outcomes of this work help the designer use optimum weight-to-torque ratio of gear; this is ultimately going to reduce the total bulk of the gear box.

Time Varying Meshing Stiffness of Cracked Sun and Ring Gears of Planetary Gear Train

2015 ◽  
Vol 772 ◽  
pp. 164-168
Author(s):  
Arif Abdullah Muhammad ◽  
Guang Lei Liu
Keyword(s):  
Gear Tooth ◽  
Planetary Gear ◽  
Mesh Point ◽  
Gear Train ◽  
Time Varying ◽  
Planetary Gear Train ◽  
Meshing Stiffness ◽  
Face Width ◽  
The Face ◽  
Applied Forces

The time varying meshing stiffness of normal and cracked spur gears of planetary gear train is studied by applying the unit normal forces at mesh point on the face width along the line of action of the single gear tooth in FE based software Ansys Workbench 14.5. The tooth deflections due to the applied forces at one mesh point are noted and a deflection matrix is established which is solved using Matlab to get net deflection and finally the meshing stiffness of gear tooth at particular mesh point. The process is repeated for other mesh points of gear tooth by rotating it to get meshing stiffness for whole gear tooth.

Deformation and Bending Stress Analysis of a Three-dimensional, Thin-rimmed Gear

2001 ◽  
Vol 124 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Shuting Li
Keyword(s):  
Critical Stress ◽  
Gear Tooth ◽  
Three Dimensional ◽  
Deformation Model ◽  
Tooth Root ◽  
Bending Stress ◽  
The Finite Element Method ◽  
Stress Point ◽  
Bending Stresses ◽  
The Web

This paper analyzed the deformations and bending stresses of a three-dimensional (3D), thin-rimmed gear (TRG) through using the finite element method (FEM) and a whole gear deformation model. The gear’s deformations and stresses at every part are analyzed in detail. In contrast with tooth bending deformations of a solid gear, 3D-TRG has not only tooth bending deformations, but also rim and web bending deformations. This paper found that the thin rim and web share about 70% deformations in the total deformations of the 3D-TRG and the gear tooth share only about 30%. It is also pointed out by this paper that not only the root stresses of the 3D-TRG are much greater than the solid gear because of the rim and web deformations, but also there are much greater stresses existing in the joint of the thin rim and the web. Especially, when the rim thickness becomes very thin, stresses at the joint shall become much greater than the root stresses. It is very necessary to regard the joint as the second critical stress point as well as the tooth root when to design 3D-TRG.

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