Computerized Design of Worm Gear Drives With Improved Conditions of Meshing and Bearing Contact

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.

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.


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.


2015 ◽  
Vol 6 (1) ◽  
pp. 31-39
Author(s):  
S. Bodzás ◽  
I. Dudás

With the knowledge of the advantageous characteristics of the cylindrical worm gear drives having arched profile in axial section and the conical worm gear drives having linear profile in axial section, a new geometric type conical worm gear drive has been designed and then manufactured, that is the conical worm gear drive having arched profile in axial section. Under same load and boundary conditions in case of the same geometric spiroid worm gear drives having arched profile and having linear profile in axial section we have done comparative finite element method analysis for evaluating the strains, deformations and stresses of this gear drives.


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):  
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.


2010 ◽  
Vol 42 ◽  
pp. 408-412
Author(s):  
Jing Lin Tong ◽  
Yun Bo Shen ◽  
Xiao Bo Wang

Based on the technology of face gear shaping, the tooth surface design and geometry were investigated that include tooth generation, limiting inner and outer radii. The computer were applied to simulated tooth contact analysis and transmission ratio of gear drive. A novice method is proposed for face gear generated by use of a general shaper. A face gear with 77 teeth was generated successfully by the shaper. For the purpose to certificate the bearing contact of gear drive, an experimental investigation was also developed in the bevel gear meshing machine. The results show the experimental bearing contact of face gear drive is correspondence to the computerized design, which validated the feasibility of face gear shaping by a general shaper.


Author(s):  
F Yang ◽  
D Su ◽  
C. R. Gentle

A new approach has been developed by the authors to estimate the load share of worm gear drives, and to calculate the instantaneous tooth meshing stiffness and loaded transmission errors. In the approach, the finite element (FE) modelling is based on the modified tooth geometry, which ensures that the worm gear teeth are in localized contact. The geometric modelling method for involute worm gears allows the tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of finite element analysis, the instantaneous meshing stiffness and loaded transmission errors are obtained and the load share is predicted. In comparison with existing methods, this approach applies loaded tooth contact analysis and provides more accurate load capacity rating of worm gear drives.


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.


2020 ◽  
Vol 21 (4) ◽  
pp. 405
Author(s):  
Sándor Bodzás

The cylindrical worm gear drives are widely used in different mechanical construction such as in the vehicle industry, the robotics, the medical appliances etc. The main property of them is the perpendicular and space bypass axes arrangement. Quite high transmission ratio could be achieved because of the high number of teeth of the worm-wheel and a little number of threads of the worm. More teeth are connected on the worm-wheel at the same time that is why higher loads and power could be transferred. In this research an Archimedean type cylindrical worm gear drive was designed. After the determination of the geometric parameters the computer-aided models were created for the LTCA analysis. Knowing of the kinematic motions of the elements the contact points of the wrapping surfaces could be determined by mathematical way. The necessary coordinate system's arrangements and matrixes were also determined. Different torques were applied during the LTCA. The changing of the distribution of the normal stress and normal deformation into different directions was followed on each connecting tooth of the worm-wheel by the torques. Based on the results consequences were determined by the created diagrams which contain the torques and the analysed mechanical parameter for each tooth.


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