Optimum Tooth-Surface Modification for Axis-Displaced Worm-Gear Drive With Cylindrical ZA Worm

Author(s):  
Takashi Matsuda ◽  
Motohiro Sato ◽  
Satoshi Matsui

Gear drives, which have larger misalignment than the maximum tolerance of misalignment for gear drives with parallel axes in the Standard of Japanese Gear Manufacture’s Association (JGMA Standard 114-02), are designated as axis-displaced gear drives in this study. So, axis-displacement is used in place of the misalignment. In this study, design system of optimum tooth-surface modification is developed for axis-displaced worm-gear drives with cylindrical ZA worm, which is sensitive to gear misalignments, to reduce the sensitivity to misalignment and to provide the high productivity and reliability. The system is composed by; (1) Axis-displaced wheel tooth-surface is defined as the envelope of worm tooth-surface family in their regular motion transmission (zero transmission error) under an axis-displacement. (2) Basic wheel tooth-surface is built by combining the axis-displaced tooth-surfaces under various axis-displacements. (3) Rack, whose pitch plane rolls on pitch cylinder of wheel, is introduced and then basic rack tooth-surface is obtained as the envelope of the basic wheel tooth-surface family in their regular relative motion. (4) It is illustrated how to get optimum rack tooth-surface from the basic rack tooth-surface. (5) Optimum wheel tooth-surface is generated as the envelope of the optimum rack tooth-surface family in their regular relative motion. (6) The performances of the axis-displaced worm-gear drive having the optimum wheel tooth-surface are analyzed by TCA (Tooth Contact Analysis) program which is developed for analysis of meshing and tooth bearing contact. The above-mentioned system is illustrated with its application for testing worm-gear drive. As a result, it is presented that the system can provide the testing worm-gear drive favorable tooth bearing contact and motion transmission, even in the maximum tolerance of misalignment in JGMA Standard 114-02.

Author(s):  
Takashi Matsuda ◽  
Motohiro Sato ◽  
Satoshi Matsui

Gear drives, which have larger misalignment than the maximum tolerance of misalignment for gear drives with parallel axes in the Standard of Japanese Gear Manufacture’s Association (JGMA Standard 114-02), are designated as axis-displaced gear drives in this study. So, axis-displacement is used in place of the misalignment. And tooth-surface modification for axis-displaced gear drives has been studied by the authors. In this study, design system for optimum tooth-surface modification is developed for axis-displaced involute helical gear drives, which are sensitive to gear misalignment, to reduce the sensitivity to misalignment and to provide the high productivity and reliability. The system is composed of; (1) Virtual rack, which is conjugate to mating standard helical gear pair in their standard relative motion, is defined for pinion and gear tooth-surface generation. And axis-displacement is relative displacement between the virtual rack and each gear, or between pinion and gear. (2) Axis-displaced tooth-surface of each gear is defined as the envelope of virtual rack tooth-surface family in their regular motion transmission (zero transmission error) under an axis-displacement. (3) Basic tooth-surface of each gear is built by combining the axis-displaced tooth-surfaces under various axis-displacements. (4) Basic rack tooth-surface for each gear is obtained as the envelope of the basic tooth-surface family in their regular relative motion. (5) It is illustrated how to get optimum rack tooth-surface from the basic rack tooth-surface. (6) Optimum tooth-surface of each gear is generated as the envelope of the optimum rack tooth-surface family in their regular relative motion. (7) Undercut around dedendum, and tooth thickness on tip circle of the optimum pinion tooth-surface are checked. (8) The performances of testing gear drive with the optimum tooth-surface of each gear are analyzed by TCA (Tooth Contact Analysis) program developed for analysis of meshing and bearing contact. The above-mentioned system is illustrated with its application for testing involute helical gear drive. As a result, it is ascertained that the system can provide the gear drive favorable tooth bearing contact and motion transmission, even in 10 times misalignment of the maximum tolerance in JGMA Standard 114-02.


Author(s):  
Ignacio Gonzalez-Perez ◽  
Alfonso Fuentes ◽  
Faydor L. Litvin ◽  
Kenichi Hayasaka ◽  
Kenji Yukishima

A new geometry of a cylindrical worm gear drive is proposed for: (i) reduction of sensitivity of the drive to errors of alignment, and (ii) observation of a favorable bearing contact. The basic ideas of new geometry are as follows: (i) the worm-gear is generated by a hob that is oversized in comparison with the worm of the drive and has a parabolic profile in normal section; (ii) the tooth surface of the worm of the drive is a conventional one. Due to deviation of the hob thread surface, the bearing contact of the worm and the worm-gear is localized. Reduction of sensitivity to misalignment and improved conditions of meshing are confirmed by application of TCA (Tooth Contact Analysis). Formation of bearing contact has been investigated by finite element method applied in 3D for more than one pair of contacting teeth. Developed ideas may be applied for various types of cylindrical worm gear drives.


Author(s):  
I. H. Seol ◽  
Faydor L. Litvin

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.


2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Wei-Liang Chen ◽  
Chung-Biau Tsay

Based on the previously developed mathematical model of a series of recess action (RA) worm gear drive (i.e., semi RA, full RA, and standard proportional tooth types) with double-depth teeth, the tooth contact analysis (TCA) technique is utilized to investigate the kinematic error (KE), contact ratio (CR), average contact ratio (ACR), instantaneous contact teeth (ICT) under different assembly conditions. Besides, the bearing contact and contact ellipse are studied by applying the surface topology method. Three numerical examples are presented to demonstrate the influence of the assembly errors and design parameters of the RA worm gear drive on the KE, CR, ACR, ICT, and contact patterns.


2000 ◽  
Vol 122 (2) ◽  
pp. 201-206 ◽  
Author(s):  
I. H. Seol

The design and simulation of meshing of a single enveloping worm-gear drive with a localized bearing contact is considered. The bearing contact has a longitudinal direction and two branches of contact path. The purpose of localization is to reduce the sensitivity of the worm-gear drive to misalignment. The author’s approach for localization of bearing contact is based on the proper mismatch of the surfaces of the hob and drive worm. The developed computer program allows the investigation of the influence of misalignment on the shift of the bearing contact and the determination of the transmission errors and the contact ratio. The developed approach has been applied for K type of single-enveloping worm-gear drives and the developed theory is illustrated with a numerical example. [S1050-0472(00)00502-X]


1999 ◽  
Vol 121 (4) ◽  
pp. 573-578 ◽  
Author(s):  
M. De Donno ◽  
F. L. Litvin

The authors propose a new approach for design and generation of low-noise, stable bearing contact gear drive with cylindrical worm. The approach is based on application of an oversized hob and varied plunging of worm generating tool. It is discovered that without plunging positive transmission errors occur (that are unacceptable for favorable conditions of force transmission). A predesigned parabolic function is provided that is able to absorb transmission errors caused by misalignment and reduce the level of vibrations, especially in the case of application of multi-thread worms. The developed approach is tested by computerized simulation of meshing and contact by the developed computer program. The investigation is accomplished for a worm-gear drive with the Klingelnberg type of the worm that is ground by a circular cone, but the proposed approach may be applied for other types of worm gear drives with cylindrical worms.


2011 ◽  
Vol 86 ◽  
pp. 327-332
Author(s):  
Jin Hua Wang ◽  
Yun Bo Shen ◽  
Ze Yong Yin ◽  
Jie Gao ◽  
Yan Ying Jiang

Load sharing is one of the main factors that determine gear strength. In this paper, Tooth Contact Analysis (TCA) and Loaded Tooth Contact Analysis (LTCA) have been performed to investigate the effect of tooth surface modification on the contact ratio, load sharing and strength of an orthogonal offset face gear drive with spur involute pinion. The results indicate that the contact ratio of 2.0 or higher could be achieved. The maximum load carried by single tooth and bending stress are significantly reduced when appropriate tooth surface modification is applied to the orthogonal offset face gear drive.


2006 ◽  
Vol 129 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Faydor L. Litvin ◽  
Kenji Yukishima ◽  
Kenichi Hayasaka ◽  
Ignacio Gonzalez-Perez ◽  
Alfonso Fuentes

The computerized design, generation, and tooth contact analysis of a Klingelnberg-type cylindrical worm gear drive is considered wherein localization of contact is obtained by application of an oversized hob and mismatch geometries of hob and worm of the drive. A computerized approach for the determination of contacting surfaces and the investigation of their meshing and contact by tooth contact analysis is presented. The developed theory results in an improvement of bearing contact and reduction of sensitivity to misalignment. The theory is illustrated with numerical examples and may be applied for other types of cylindrical worm gear drives.


Author(s):  
Faydor L. Litvin ◽  
I. H. Seol ◽  
K. Kim

Abstract The design and simulation of meshing of a single-enveloping worm-gear drive with a localized bearing contact is considered. The bearing contact has a longitudinal direction. The purpose of localization is to reduce the sensitivity of the worm-gear drive to misalignment. The authors’ approach for localization of bearing contact is based on the proper mismatch of the sufaces of the hob and the drive worm. The developed computer program allows the investigation of the influence of misalignment on the shift of the bearing contact and allows determination of the transmission errors. The developed approach is applicable for all types of single-enveloping worm-gear drives. The developed theory is illustrated with a numerical example.


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