Determination of Maximum Possible Contact Ratios for Spur Gear Drives With Small Number of Teeth

1995 ◽  
Author(s):  
M. A. Sahir Arikan
Keyword(s):  
Spur Gear ◽  
Number Of Teeth ◽  
Fillet Radius ◽  
Gear Drives

Abstract Maximum possible contact ratios which can be obtained by making use of x-zero gear pairs are determined for spur gear drives with small number of teeth. Rack cutter tip fillet radius and rack cutter geometry are taken into consideration in the analysis. Results for gear drives with various numbers of teeth and cut by rack cutters standardized by ISO and AGMA are given in forms of tables. Results are also compared with addendum modification coefficients recommended by ISO.

An Approach for Solving the Contact Problem in Spur Gear Transmissions Considering Gear Misalignments

2015 ◽  
Author(s):  
V. Roda-Casanova ◽  
F. Sanchez-Marin ◽  
J. L. Iserte
Keyword(s):  
Contact Problem ◽  
Computational Cost ◽  
Element Model ◽  
Spur Gear ◽  
New Approach ◽  
Load Distributions ◽  
Bending Stresses ◽  
Gear Drives ◽  
Contact Pressures

Gear misalignments originate unwanted uneven load distributions that increase contact pressures and the bending stresses, reducing the service life of gear drives. Therefore, it is very important to take into account the misalignments in the determination of contact pressures when designing a gear transmission. Some of these misalignments are related to manufacturing and assembly errors, but others are produced by the deformation of the shafts when power is transmitted. These deformations cause misalignment of the gears, modifying the contact bearing and the pressure distribution, which modifies the deformation of the shafts, leading to a coupled problem not always easy to solve. In this work, a new approach to solve this problem is proposed, based on an iterative algorithm which uncouples the determination of the deformation of the shafts from the contact problem. The proposed approach has been tested through various configurations of spur gear drives. The obtained results are compared with those obtained using a finite element model, showing a good correlation between them, but with a significant reduction of the computational cost.

The Undercutting of Hobbed Spur Gear Teeth

1983 ◽  
Vol 105 (1) ◽  
pp. 122-128 ◽  
Author(s):  
R. G. Mitchiner ◽  
H. H. Mabie ◽  
H. Moosavi-Rad
Keyword(s):  
Spur Gear ◽  
Gear Teeth ◽  
Pressure Angle ◽  
Number Of Teeth ◽  
Minimum Number ◽  
Straight Portion ◽  
Base Circle ◽  
Tooth Flank ◽  
General Method

A general method is presented for the determination of the minimum number of teeth that can be cut in a spur gear without undercutting by a rounded-tooth tip hob. The minimum number of teeth to produce undercutting was investigated for three trochoid/tooth-profile relations: (1) trochoid tangent to the involute profile at the base circle, (2) trochoid tangent to a straight portion of the tooth flank, and (3) trochoid intersecting the involute profile at the base circle. It was found that in order to avoid undercutting, the minimum number of teeth cut into a gear occurs when the trochoid is tangent to the involute at the base circle. There is no set of hob parameters such that the trochoid intersects the involute profile at the base circle nor does the case of the trochoid being tangent to a straight flank exist. A set of figures representing the variation of the amount of undercutting versus the number of teeth, radius of hob-tooth tip, hob addendum, cutting pressure angle, and the corresponding derivatives are included for a typical gear.

Performance Rating and Optimization of Spur Gear Drives With Small Number of Teeth

2000 ◽  
Author(s):  
M. A. Sahir Arikan
Keyword(s):  
Gear Tooth ◽  
Spur Gear ◽  
Maximum Length ◽  
Performance Rating ◽  
Tooth Root ◽  
Contact Ratio ◽  
Geometry Factor ◽  
Factor I ◽  
Number Of Teeth ◽  
Gear Drives

Abstract Performance rating of spur gear drives with small number of teeth is made and variations of contact ratio, circular tooth thicknesses at pinion and gear tooth tips, lengths of the pinion addendum and dedendum portions of the line of action, AGMA geometry factor J for the pinion and the gear and their ratio, and AGMA geometry factor I with addendum modification coefficient are determined. Thus, it is made possible to design gear drives with properties such as, maximum possible contact ratio, maximum length of the pinion addendum portion of the line of action, maximum length of the pinion dedendum portion of the line of action, equal AGMA geometry factors J for the pinion and the gear (i.e. equal pinion and gear tooth root stresses), and maximum AGMA geometry factor I (i.e. minimum tooth contact stress). Rack cutter tip fillet radius and rack cutter geometry are considered in the analysis, which are the basic factors that determine the gear tooth fillet profile.

scholarly journals Determination of the ISO face load factor in spur gear drives by the finite element modeling of gears and shafts

2013 ◽  
Vol 65 ◽  
pp. 1-13 ◽  
Author(s):  
Victor Roda-Casanova ◽  
Francisco T. Sanchez-Marin ◽  
Ignacio Gonzalez-Perez ◽  
Jose L. Iserte ◽  
Alfonso Fuentes
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Spur Gear ◽  
Load Factor ◽  
Element Modeling ◽  
Gear Drives

The Mechanical Efficiency of Epicyclic Gear Trains

1993 ◽  
Vol 115 (3) ◽  
pp. 645-651 ◽  
Author(s):  
E. Pennestri` ◽  
F. Freudenstein
Keyword(s):  
Mechanical Efficiency ◽  
Spur Gear ◽  
Efficiency Analysis ◽  
Gear Drive ◽  
Epicyclic Gear ◽  
Gear Trains ◽  
Gear Drives ◽  
General Computer Program ◽  
General Computer

The analysis of mechanical efficiency constitutes an important phase in the design analysis of gear drives. The objective of this investigation has been the development of a general algorithm for the determination of efficiency in split-power spur-gear trains. The model includes meshing losses only; for a more realistic estimation other sources can be considered separately. The systematic nature of the formulation, based on the dual correspondence between the kinematic structure of the gear drive and a labelled graph, allows a ready coding of the efficiency analysis in a general computer program. The numerical results are in line with those given by other authors using different methodologies.

The Wolfrom Gear Train: A Case of Highest-Complexity Related Modifications of the Tooth Meshing

2009 ◽  
Author(s):  
Kiril Arnaudov ◽  
Dimitar Karaivanov
Keyword(s):  
Design Problem ◽  
High Speed ◽  
Technical Problem ◽  
Gear Train ◽  
Speed Ratio ◽  
Specific Design ◽  
Number Of Teeth

The Wolfrom gear is suitable for high speed ratios with an efficiency which is not optimal, but still acceptable. The version with single-rim satellites has significant design and technological advantages. However, the determination of the most appropriate modification coefficients poses a technical problem as the modifications are now related instead of being chosen independently. The geometrical calculations of the single-rim satellites version are performed in the paper. Speed ratio, number of teeth of the satellites, pressure angles and modification coefficients are determined. Advisable values for these parameters are given. As an example a specific design problem for the replacement of a three-stage planetary reducer (consisting of 15 gears) with a Wolfrom gear train (6 gears) the following calculations were performed.

scholarly journals Stresses in Spur Gear Teeth and Their Strength as Influenced by Fillet Radius

1985 ◽  
Vol 107 (1) ◽  
pp. 1
Author(s):  
Manfred Christian Otto Hirt ◽  
John Maddock ◽  
Dennis P. Townsend
Keyword(s):  
Spur Gear ◽  
Gear Teeth ◽  
Fillet Radius

LOAD AND STRESS ANALYSIS OF CYLINDRICAL WORM GEARING USING TOOTH SLICING METHOD

2006 ◽  
Vol 30 (1) ◽  
pp. 97-111 ◽  
Author(s):  
A.H. Falah ◽  
A.H. Elkholy
Keyword(s):  
Spur Gear ◽  
Operating Conditions ◽  
Stress Distributions ◽  
Worm Gearing ◽  
Tooth Stiffness ◽  
Worm Gears ◽  
Foundation Deformation ◽  
Stiffness Variation ◽  
Slicing Method

A method for the determination of load and stress distributions of the instantaneously engaged teeth of cylindrical worm gears is represented in this paper. The method is based on the assumption that both the worm and gear can be modeled as a series of spur gear slices. The exact geometry and point of load application of each slice depends on its location within the mesh. By calculating the applied load and stress for each slice, the same can be determined for the entire worm gear set. The method takes into consideration tooth stiffness variation from root to tip, tooth bending deflection, local contact deformation, tooth foundation deformation and, the influence of gear parameters on load and stress. Calculated results were found to be in agreement with experimental and analytical ones obtained from literature under given operating conditions.

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