Tooth Contact Analysis for Helical Gears with Pinion Circular Arc Teeth and Gear Involute Shaped Teeth

1989 ◽  
Vol 111 (2) ◽  
pp. 278-284 ◽  
Author(s):  
C.-B. Tsay ◽  
Z. H. Fong
Keyword(s):  
Gear Tooth ◽  
Tooth Surface ◽  
Tooth Contact Analysis ◽  
Circular Arc ◽  
Helical Gears ◽  
Numerical Examples ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Helical Gearing ◽  
Center Distance

In this paper, the theory of gearing and the concept of differential geometry have been applied to deal with the relations of two mating gears and of their bearing contact. The gear tooth surfaces of this type of gearing contact with each other at every instant at one point instead of one line. The bearing contact of the gear tooth surface is localized and the center of the bearing contact moves along the tooth surface. Thus, this type of helical gearing is not as sensitive to center distance variation and gear axes misalignment. This paper covered the solutions to the following problems: (1) Computer simulation of the conditions of meshing and bearing contact and (2) Investigation of the sensitivity of gears to the errors of manufacturing and assembly. A method of compensation for the dislocation of the bearing contact induced by errors of manufacturing and assembly has been proposed. Five numerical examples have also been presented to illustrate the influence of the above mentioned errors and the method of compensation for the dislocation of bearing contact.

Helical Gears With Circular Arc Teeth: Simulation of Conditions of Meshing and Bearing Contact

1985 ◽  
Vol 107 (4) ◽  
pp. 556-564 ◽  
Author(s):  
F. L. Litvin ◽  
Chung-Biau Tsay
Keyword(s):  
Gear Tooth ◽  
Circular Arc ◽  
Helical Gears ◽  
Numerical Examples ◽  
Technological Method ◽  
Bearing Contact ◽  
Paper Cover ◽  
Tooth Surfaces ◽  
Center Distance

Methods proposed in this paper cover: (a) generation of conjugate gear tooth surfaces with localized bearing contact; (b) derivation of equations of gear tooth surfaces; (c) simulation of conditions of meshing and bearing contact; (d) investigation of the sensitivity of gears to the errors of manufacturing and assembly (to the change of center distance and misalignment); and (e) improvement of bearing contact with the corrections of tool settings. Using this technological method we may compensate for the dislocation of the bearing contact induced by errors of manufacturing and assembly. The application of the proposed methods is illustrated by numerical examples. The derivation of the equations is given in the Appendix.

Application and Investigation of Modified Helical Gears With Several Types of Geometry

2007 ◽  
Author(s):  
Ignacio Gonzalez-Perez ◽  
Alfonso Fuentes ◽  
Faydor L. Litvin ◽  
Kenichi Hayasaka ◽  
Kenji Yukishima
Keyword(s):  
Gear Tooth ◽  
Tooth Surface ◽  
Contact Ratio ◽  
Tooth Contact Analysis ◽  
Helical Gears ◽  
Transmission Errors ◽  
Advantages And Disadvantages ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Gear Drives

Involute helical gears with modified geometry for transformation of rotation between parallel axes are considered. Three types of topology of geometry are considered: (1) crowning of pinion tooth surface is provided only partially by application of a grinding disk; (2) double crowning of pinion tooth surface is obtained applying a grinding disk; (3) concave-convex pinion and gear tooth surfaces are provided (similar to Novikov-Wildhaber gears). Localization of bearing contact is provided for all three types of topology. Computerized TCA (Tooth Contact Analysis) is performed for all three types of topology to obtain: (i) path of contact on pinion and gear tooth surfaces; (ii) negative function of transmission errors for misaligned gear drives (that allows the contact ratio to be increased). Stress analysis is performed for the whole cycle of meshing. Finite element models of pinion and gear with several pairs of teeth are applied. A relative motion is imposed to the pinion model that allows friction between contact surfaces to be considered. Numerical examples have confirmed the advantages and disadvantages of the applied approaches for generation and design.

Determination of Principal Curvatures and Contact Ellipse for Profile Crowned Helical Gears

1998 ◽  
Author(s):  
Pin-Hao Feng ◽  
Faydor L. Litvin ◽  
Dennis P. Townsend ◽  
Robert F. Handschuh
Keyword(s):  
Gear Tooth ◽  
Principal Curvatures ◽  
Circular Arc ◽  
Helical Gears ◽  
Parabolic Curve ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Simplified Solution ◽  
Gear Drives ◽  
Contact Ellipse

Abstract Helical gears with localized bearing contact of tooth surfaces achieved by profile crowning of tooth surfaces are considered. Profile crowning is analyzed through the use of two imaginary rack-cutters with mismatched surfaces. The goal is to determine the dimensions and orientation of the instantaneous contact ellipse from the principle curvatures of the pinion and gear tooth surfaces. A simplified solution to this problem is proposed based on the approach developed for correlation of principal curvatures and directions of generating and generated tooth surfaces. The equations obtained are applied to three cases of profile crowning where the normal profiles of the rack-cutters are: (i) parabolic curves: (ii) circular arcs; and (iii) a combination of a straight line for one of the rack-cutters and a parabolic curve or a circular arc for the mating rack-cutter. The gear drives can be the combination of a pinion generated by a parabolic curve or a circular arc and gear generated by one of three cases mentioned above.

Compensating analysis of a double circular-arc helical gear by computerized simulation of meshing

2001 ◽  
Vol 215 (7) ◽  
pp. 759-771 ◽  
Author(s):  
C-K Chen ◽  
C-Y Wang
Keyword(s):  
Mathematical Model ◽  
Helical Gear ◽  
Tooth Contact Analysis ◽  
Angular Misalignment ◽  
Circular Arc ◽  
Numerical Examples ◽  
Transmission Errors ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Computerized Simulation

A mathematical model of a stepped double circular-arc helical tooth profile with two centre offsets is developed. The conditions of gear meshing that reflect manufacturing and assembly errors are simulated. The locations of bearing contact and the contact path pattern of mating tooth surfaces are determined by tooth contact analysis (TCA). By applying the proposed mathematical model and TCA, single error impact can be determined. To compensate for offset and angular misalignment, the authors propose an adjustable bearing whereby transmission errors can be minimized. The investigation is illustrated with several numerical examples.

scholarly journals Computerized Design and Generation of Low-Noise Helical Gears with Modified Surface Topology

1995 ◽  
Vol 117 (2A) ◽  
pp. 254-261 ◽  
Author(s):  
F. L. Litvin ◽  
N. X. Chen ◽  
J. Lu ◽  
R. F. Handschuh
Keyword(s):  
Gear Tooth ◽  
Error Function ◽  
Transmission Error ◽  
Low Noise ◽  
Surface Topology ◽  
Helical Gears ◽  
Transmission Errors ◽  
Bearing Contact ◽  
Pinion Gear ◽  
Tooth Surfaces

An approach for the design and generation of low-noise helical gears with localized bearing contact is proposed. The approach is applied to double circular arc helical gears and modified involute helical gears. The reduction of noise and vibration is achieved by application of a predesigned parabolic function of transmission errors that is able to absorb a discontinuous linear function of transmission errors caused by misalignment. The localization of the bearing contact is achieved by the mismatch of pinion-gear tooth surfaces. Computerized simulation of meshing and contact of the designed gears demonstrated that the proposed approach will produce a pair of gears that has a parabolic transmission error function even when misalignment is present. Numerical examples for illustration of the developed approach are given.

Computerized Design, Generation and Simulation of Meshing and Contact of Modified Flender Worm-Gear Drives

1996 ◽  
Author(s):  
I. H. Seol ◽  
Faydor L. Litvin
Keyword(s):  
Gear Tooth ◽  
Worm Gear ◽  
Numerical Examples ◽  
Transmission Errors ◽  
Gear Drive ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Design Generation ◽  
Computerized Simulation ◽  
Gear Drives

Abstract The worm and worm-gear tooth surfaces of existing design of Flender gear drive are in line contact at every instant and the gear drive is very sensitive to misalignment. Errors of alignment cause the shift of the bearing contact and transmission errors. The authors propose : (1) Methods for computerized simulation of meshing and contact of misaligned worm-gear drives of existing design (2) Methods of modification of geometry of worm-gear drives that enable to localize and stabilize the bearing contact and reduce the sensitivity of drives to misalignment (3) Methods for computerized simulation of meshing and contact of worm-gear drives with modified geometry The proposed approach was applied as well for the involute (David Brown) and Klingelnberg type of worm-gear drives. Numerical examples that illustrate the developed theory are provided.

Revisiting Plane-Generated Gear Tooth Surfaces: A Novel Design Perspective

2015 ◽  
Author(s):  
Alessio Artoni ◽  
Massimo Guiggiani
Keyword(s):  
Gear Tooth ◽  
Transmission Function ◽  
Tooth Surface ◽  
Generation Process ◽  
Noise Emission ◽  
Helical Gears ◽  
Beveloid Gears ◽  
Tooth Surfaces ◽  
Involute Gears ◽  
The One

The teeth of ordinary spur and helical gears are generated by a (virtual) rack provided with planar generating surfaces. The resulting tooth surface shapes are a circle-involute cylinder in the case of spur gears, and a circle-involute helicoid for helical gears. Advantages associated with involute geometry are well known: in particular, the motion transmission function is insensitive to center distance variations, and contact lines (or points, when a corrective surface mismatch is applied) evolve along a fixed plane of action, thereby reducing vibrations and noise emission. As a result, involute gears are easier to manufacture and assemble than non-involute gears, and silent to operate. A peculiarity of their generation process is that the motion of the generating planar surface, seen from the fixed space, is a rectilinear translation (while the gear blank is rotated about a fixed axis): the component of such translation that is orthogonal to the generating plane is the one that ultimately dictates the shape of the generated, envelope surface. Starting from this basic fact, we set out to investigate this type of generation-by-envelope process and to profitably use it to explore new potential design layouts. In particular, with some similarity to the basic principles underlying conical involute (or Beveloid) gears, but within a broader scope, we propose a generalization of these concepts to the case of involute surfaces for motion transmission between skew axes (and intersecting axes as a special case). Analytical derivations demonstrate the theoretical possibility of involute profiles transmitting motion between skew axes through line contact and, perihaps more importantly, they lead to apparently novel geometric designs featuring insensitivity of transmission ratio to all misalignments within relatively large limits. The theoretical developments are confirmed by various numerical examples.

Investigation of tooth contact deviations from the plane of action and their effects on gear transmission error

2005 ◽  
Vol 219 (5) ◽  
pp. 501-509 ◽  
Author(s):  
C H Wink ◽  
A L Serpa
Keyword(s):  
Gear Tooth ◽  
Transmission Error ◽  
Contact Analysis ◽  
Gear Transmission ◽  
Tooth Surface ◽  
Tooth Contact ◽  
Helical Gears ◽  
Influence Coefficients ◽  
Manufacturing Errors ◽  
Tooth Surfaces

In this paper tooth contact deviations from the plane of action and their effects on gear transmission error are investigated. Tooth contact deviations come from intentional modification of involute tooth surfaces such as tip and root profile relief; manufacturing errors such as adjacent pitch error, profile errors, misalignment and lead errors; and tooth elastic deflections under load, for example, bending and local contact deflections. Those deviations are usually neglected on gear tooth contact models. A procedure to calculate the static transmission error of spur and helical gears under loading is proposed. In the proposed procedure, contact analysis is carried out on the whole tooth surface, eliminating the usual assumption that tooth contact occurs only on the plane of action. Lead and profile modifications, manufacturing errors and tooth elastic deflections are considered in the calculation procedure. The method of influence coefficients is employed to calculate the tooth elastic deflections. Load distribution on gear meshing is determined using an iterative-incremental method. Results of some numerical examples of spur and helical gears are analysed and discussed. The results indicate that the tooth contact deviations from the plane of action can lead to imprecision on the gear transmission error calculation if they are not take into account. Therefore, the proposed procedure provides a more accurate calculation methodology of gear transmission error, since a global contact analysis is done.

New developments in the design and generation of gear drives

2001 ◽  
Vol 215 (7) ◽  
pp. 747-757 ◽  
Author(s):  
F. L. Litvin ◽  
A Fuentes ◽  
A Demenego ◽  
D Vecchiato ◽  
Q Fan
Keyword(s):  
Point Contact ◽  
Tooth Surface ◽  
Helical Gears ◽  
Transmission Errors ◽  
Bevel Gears ◽  
Bearing Contact ◽  
Analysis And Synthesis ◽  
Tooth Surfaces ◽  
Design Generation ◽  
Gear Drives

Design, generation and simulation of the meshing and contact of gear drives with favourable bearing contact and reduced noise are considered. The proposed approach is based on replacement of the instantaneous line of contact of tooth surfaces by point contact and on application of a predesigned parabolic function of transmission errors that is able to absorb linear discontinuous functions of transmission errors caused by misalignment. Basic algorithms for analysis and synthesis of gear drives are presented. The developed theory is applied for design and generation of the following gear drives with modified geometry: (a) spur and helical gears, (b) a new version of Novikov-Wildhaber (N-W) helical gears, (c) asymmetric face gear drives with a spur pinion, (d) formate-cut spiral bevel gears. Generation of the tooth surface of a worm gear is presented as the formation of a two-branch envelope. The discussed topics are illustrated with examples.

Determination of Principal Curvatures and Contact Ellipse for Profile Crowned Helical Gears

1999 ◽  
Vol 121 (1) ◽  
pp. 107-111 ◽  
Author(s):  
P.-H. Feng ◽  
F. L Litvin ◽  
D. P. Townsend ◽  
R. F. Handschuh
Keyword(s):  
Gear Tooth ◽  
Principal Curvatures ◽  
Helical Gears ◽  
Bearing Contact ◽  
Pinion Gear ◽  
Straight Line ◽  
Tooth Surfaces ◽  
Simplified Solution ◽  
Contact Ellipse

Helical gears with localized bearing contact of tooth surfaces achieved by profile crowning of tooth surfaces are considered. Profile crowning is provided by application of two imaginary rack-cutters with mismatched surfaces. The goal is to determine the dimensions and orientation of the instantaneous contact ellipse that requires the determination of principle curvatures of pinion-gear tooth surfaces. A simplified solution to this problem is proposed based on the approach developed in [1, 2] for correlation of principal curvatures and directions of generating and generated tooth surfaces. The obtained equations are applied for profile crowning where the normal profiles of the rack-cutters are either a circular arc or a straight line.

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