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.

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.

Kinematic and Geometric Models of Gear Drives

1996 ◽  
Vol 118 (4) ◽  
pp. 544-550 ◽  
Author(s):  
F. L. Litvin ◽  
I. H. Seol ◽  
D. Kim ◽  
J. Lu ◽  
A. G. Wang ◽  
...  
Keyword(s):  
Gear Tooth ◽  
Helical Gears ◽  
Transmission Errors ◽  
Bevel Gears ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Involute Gears ◽  
Computerized Simulation ◽  
Gear Drives ◽  
The Impact

A methodology is proposed for the modification of gear tooth surfaces that reduces the impact of gear drive misalignment, the shift of the bearing contact (accompanied in some cases with edge contact), and the occurrence of discontinuous functions of transmission errors. The proposed approach is tested by computerized simulation of meshing and contact for unloaded and loaded gear drives. Applications of geometry modifications to the design of spur and helical involute gears, double-circular helical gears, face-gear drives, face-milled spiral bevel gears with constant tooth height and worm-gear drives are represented.

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.

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.

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.

Development and Comparison of Shaft-Gear Models for the Computation of Gear Misalignments due to Power Transmission

2011 ◽  
Author(s):  
Victor Roda-Casanova ◽  
Jose L. Iserte-Vilar ◽  
Francisco Sanchez-Marin ◽  
Alfonso Fuentes-Aznar ◽  
Ignacio Gonzalez-Perez
Keyword(s):  
Power Transmission ◽  
Gear Tooth ◽  
Beam Theory ◽  
Spur Gear ◽  
The Finite Element Method ◽  
Transmission Errors ◽  
Bearing Contact ◽  
Torque Transmission ◽  
Tooth Surfaces ◽  
Gear Drives

Gear misalignments cause transmission errors, the shift of the bearing contact and may reduce substantially the life of gears. Some gear misalignments are caused directly by shafts misalignments but others are mainly related with the torque transmission and shaft bending. Even for perfectly aligned gear drives, shaft bending due to power transmission causes the shifting of the bearing contact towards the edge of the gear tooth surfaces for those non-modified gear drives with theoretical lineal contact. In this paper, four different models (two based on the Bernoulli’s beam theory and two based on the finite element method) have been proposed for shaft and gear modeling in order to estimate misalignments of gears due to power transmission in a conventional spur gear transmission. The influence of transmitted torque, length of shafts and relative position of gears over the shafts on the errors of alignment has been investigated.

Generation and TCA of Straight Bevel Gear Drive with Modified Geometry

2011 ◽  
Vol 86 ◽  
pp. 403-406 ◽  
Author(s):  
Ji Song Jiao ◽  
Xue Mei Cao
Keyword(s):  
Point Contact ◽  
Longitudinal Direction ◽  
Bevel Gear ◽  
Tooth Surface ◽  
Tooth Contact Analysis ◽  
Bevel Gears ◽  
Straight Bevel Gear ◽  
Bearing Contact ◽  
Tooth Surfaces ◽  
Gear Drives

In order to reduce the sensitivity of straight bevel gear drives to misalignment, a new geometry of such gear drives is proposed in longitudinal direction. Point contact instead of line contact of tooth surfaces is achieved by longitudinal crowning of pinion tooth surface. The tooth surface modeling and tooth contact analysis (TCA) of straight bevel gear drives have been established. TCA program of a pair of straight bevel gears was performed in MATLAB and tooth bearing contact and transmission errors were obtained.

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

1994 ◽  
Author(s):  
F. L. Litvin ◽  
N. X. Chen ◽  
J. Lu ◽  
R. F. Handschuh
Keyword(s):  
Gear Tooth ◽  
Low Noise ◽  
Surface Topology ◽  
Helical Gears ◽  
Transmission Errors ◽  
Bearing Contact ◽  
Pinion Gear ◽  
Tooth Surfaces ◽  
Modified Surface ◽  
Computerized Simulation

Abstract An approach for 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 parabolic transmission errors function when misalignment is present. Numerical examples for illustration of the developed approach are given.

Tooth Contact Analysis of Face Gear Drive Modified by a Grinding Worm

2010 ◽  
Vol 139-141 ◽  
pp. 1154-1157 ◽  
Author(s):  
Hui Guo ◽  
Ning Zhao ◽  
Hao Gao
Keyword(s):  
Gear Tooth ◽  
Contact Analysis ◽  
Tooth Surface ◽  
Alignment Error ◽  
Contact Ratio ◽  
Face Gear ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Gear Drive ◽  
Bearing Contact

This paper proposes a modification method for tooth surface of face gear drive with a grinding worm on a numerical grinding machine. The surface equation of grinding worm is derived, and the coordinate System of generating the worm is established. Tooth contact analysis (TCA) is performed to investigate the performance of face gear drive before and after modification, and the alignment error is considered. This method can obtain a more stable bearing contact in contrast to the method by increasing tooth number of shaper. The longitudinal bearing contact on the face-gear tooth surface has been obtained which will increase the contact ratio. By modification the edge contact at surface edges of the gears can be avoided and the modification magnitude can be controlled freely.

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