Variable height modification of TA worm drive

2018 ◽  
Vol 233 (1) ◽  
pp. 227-243 ◽  
Author(s):  
Chongfei Huai ◽  
Yaping Zhao
Keyword(s):  
Theoretical Analysis ◽  
Contact Line ◽  
Gear Tooth ◽  
Computing Methods ◽  
Normal Operation ◽  
Tooth Surface ◽  
Modification Method ◽  
Worm Gearing ◽  
Meshing Characteristics ◽  
Worm Drive

The related research shows that a constant contact line, which is negative for the normal operation of the worm gearing, exists on the middle of the unmodified and the constant height modified TA worm wheel surface. To overcome this drawback, a variable height modification method is proposed for the TA worm drive. In line with this modification method, the height modification parameter is variable during the whole processing cycle. Accordingly, the obtained gearing can be named as the variable height modified TA worm drive. The mathematical model for the meshing analysis of this novel worm drive is established according to its generation mechanism and the mesh theory of gearing. The reason why the variable height modification can remove the constant contact line on the worm gear tooth surface is analyzed in detail. In addition, the classification criterion of the transmission type is also derived. The computing methods of the key points on the contact zone boundary and the instantaneous meshing line are elaborated. On the basis of the above theoretical analysis, the meshing characteristics of this novel worm gearing are well investigated. The results manifest that the above theoretical analysis is valid, and the obtained gearing has favorable meshing properties. Furthermore, it is pointed out that the linear variable height modification with larger quantity can be recommended as the ideal strategy in practice.

scholarly journals Meshing characteristics of a sphere–face gear pair with variable shaft angle

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985951 ◽  
Author(s):  
Lei Liu ◽  
Jinzhao Zhang
Keyword(s):  
Gear Tooth ◽  
Transmission Error ◽  
Tooth Surface ◽  
Gear Pair ◽  
Face Gear ◽  
Tooth Contact Analysis ◽  
Contact Points ◽  
Shaft Angle ◽  
Meshing Characteristics ◽  
Curvature Interference

This article presents a sphere–face gear pair by substituting the convex spherical gear for the pinion of a conventional face gear pair. The sphere–face gear pair not only maintains the advantages of the face gear pair with a longitudinally modified pinion but also allows variable shaft angles or large axial misalignments. Meshing characteristics of the proposed gear pair are studied in this article. The mathematical models of the sphere–face gear pair are derived based on machining principles. The tooth contact analysis (TCA) and curvature interference check are conducted for the sphere–face gear pair with variable shaft angles. The loaded TCA is also implemented utilizing the finite element method. The results of numerical examples show that proposed gear pair has the following features. Geometrical transmission error of constant shaft angle or varying shaft angle is zero; contact points of the sphere–face gear set with variable shaft angle are located near the centre region of face gear tooth surface; there is no curvature interference in meshing; and transmission continuity of the gear pair can be guaranteed in meshing.

A General Method for Computing Worm Gear Conjugate Mesh Property: Part 2—The Mathematic Model of Worm Gear Manufacturing and Working Processes

1989 ◽  
Vol 111 (1) ◽  
pp. 148-152 ◽  
Author(s):  
Changqi Zheng ◽  
Jirong Lei
Keyword(s):  
Contact Line ◽  
Relative Velocity ◽  
Velocity Vector ◽  
Gear Tooth ◽  
Mathematic Model ◽  
Worm Gear ◽  
Tooth Surface ◽  
Gear Manufacturing ◽  
General Method ◽  
Working Processes

Part 2 of this article is devoted to building a generalized mathematic model of worm gear manufacturing and working processes which can be used for calculating the contact line, the profile, the normal curvature, the conjugate boundary and the angle between the directions of contact line and relative velocity vector for any kind of worm gear tooth surface.

A General Modification Theory for Double-Enveloping Hourglass Worm Drives

2011 ◽  
Vol 486 ◽  
pp. 279-282 ◽  
Author(s):  
Ya Ping Zhao ◽  
Tian Chao Wu
Keyword(s):  
Singular Points ◽  
Worm Gearing ◽  
Meshing Equation ◽  
Meshing Characteristics ◽  
Special Case ◽  
Worm Drive

A universal modification theory is developed for all kinds of hourglass worm drives, no matter what shape the generating surface of the worm is. Based on the theory established, toroidal worm drives can be classified into two main categories: with singular points and without singular points. That is to say, the unmodified hourglass worm gearing is merely a special case of the modified one in essence. Furthermore, the meshing characteristics of a double-enveloping toroidal worm drive are entirely up to the situation of the solution of the meshing equation of the second envelope.

Optimal Design of Modified Cylindrical Gear Based on Minimum Flash Temperature of Tooth Surfaces

2013 ◽  
Vol 655-657 ◽  
pp. 573-577
Author(s):  
Jin Ke Jiang ◽  
Zong De Fang ◽  
Xian Long Peng
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Contact Line ◽  
Gear Tooth ◽  
Tooth Surface ◽  
Uniform Grid ◽  
Normal Vector ◽  
Flash Temperature ◽  
Oil Film ◽  
Tooth Surfaces

Considering the gap of the contact line of modified involute cylindrical gears influencing on loads, oil film thickness, the friction coefficient was determined on the basis theory of TCA、 LTCA and EHL. so oil film thickness and friction coefficient corresponded with loads on contact line were dispersed, which was used to computed discrete temperature according to the Blok flash temperature formula. and an approach of modified tooth surface optimum design based on the minimum flash temperature was proposed: the modified tooth surfaces was defined as a sum of theoretical tooth and cubic B-spline fit surface based on the uniform grid points created by double parabolas and a straight line and whose normal vector was deduced, besides, used genetic algorithm to optimize the parameter of curve, and get the best modified gear tooth surfaces. the results shows that oil film is thicker in engaging-out, coefficient of friction is contrary, which is responsible for lower flash temperature in engaging-in, besides the flash temperature has little changes in the single tooth meshing zone, and helical gear has a lower flash temperature than spur gear due to higher overlap ratio.

A Study on Hourglass-Worm Gearings Designed to Concentrate Surface Normals: Design for Worm Gearings With a Large Lead Angle

1992 ◽  
Author(s):  
Hiroshi Gunbara ◽  
Shigeyuki Shimachi ◽  
Tohru Kobayashi ◽  
Hiroshi Kawada
Keyword(s):  
Elastic Deformation ◽  
Deformation Theory ◽  
Gear Tooth ◽  
Design Concept ◽  
Tooth Surface ◽  
Edge Contact ◽  
Lead Angle ◽  
Tooth Surfaces ◽  
Worm Gearing

Abstract For moderating the edge contact of gear tooth surfaces on load, a new concept has been proposed on designing worm gearing. As a first step of research, restricting a field of application of the designing concept, a few methods for generating tooth surface of hourglass worm gearing having a small lead angle have been devised. This paper tries to apply this designing concept to wider general use — an hourglass worm gearings with a large lead angle. First, the worm axis displacement relative to the wheel axis is roughly calculated by means of elastic deformation theory. And, this idea is applied to the gear designs using two kinds of hourglass worm gearings. As a result, validity of this design concept is substantiated also in the case of large lead angle of worm gearing.

Surface design and tooth contact analysis of an innovative modified spur gear with crowned teeth

2005 ◽  
Vol 219 (2) ◽  
pp. 193-207 ◽  
Author(s):  
J-L Li ◽  
S-T Chiou
Keyword(s):  
Gear Tooth ◽  
Point Contact ◽  
Spur Gear ◽  
Contact Analysis ◽  
Tooth Surface ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Surface Design ◽  
Tooth Surfaces ◽  
Meshing Characteristics

An innovative modified spur gear with crowned teeth and its generating mechanism are proposed in this study. The main purpose of tooth surface modification is to change line contact to point contact at the middle of gear tooth surfaces in order to avoid edge contact resulting from possible unavoidable axial misalignment. Moreover, the surface of one gear tooth can be generated with just one cutting process, thereby facilitating easy manufacturing. Based on gearing theory, the model for surface design is developed. A tooth contact analysis (TCA) model for the modified gear pair is also built to investigate meshing characteristics, so that transmission errors (TEs) under assembly errors can also be studied. Examples are included to verify the correctness of the models developed and to demonstrate gear characteristics.

scholarly journals Simulation and Analysis on Tooth Meshing Ease-Off Surface of Gears Based on Polynomial Topology Modification

2020 ◽  
Vol 38 (4) ◽  
pp. 897-903
Author(s):  
Bingyang Wei ◽  
Xuemei Cao ◽  
Xiaozhong Deng
Keyword(s):  
Contact Line ◽  
Simulation Method ◽  
Transmission Error ◽  
Topological Optimization ◽  
Tooth Surface ◽  
Surface Mesh ◽  
Order Polynomial ◽  
Meshing Characteristics ◽  
Topological Construction ◽  
Topology Modification

Based on the principles of common-generating conjugation mapping of pinion-rank-gear meshing, the constructing of ease-off surface has been done by means of the topology modification of the 4-order polynomial surface. The simulation method of tooth surface mesh is purposed based on the ease-off surface. By analyzing topological structure characteristics of ease-off surface such as modification gradient curves, contact line-off and contact path-off, the meshing characteristics such as the contact area, the contact line and transmission error are determined. It is stated on the interaction relations of coefficients of the 4-order polynomial to the topological construction of surface. The methods for reconstruction and analysis of ease-off surface with considering axis misalignments are presented by the direct transformation of coordinate systems. Taking the topological construction of four kinds of surfaces as examples, characteristics parameters such as modification gradient of tooth surface, contact path and transmission errors are simulated. They are expounded on the corresponding parameters of controlling form and adjusting methods for tooth surface. These methods take goals of adjusting-modification and controlling-property for tooth surface mesh. It is improved and developed the meshing analysis method of ease-off surface of tooth. The presented method is liable to provide the basis data for the further loaded contact analysis of complicated tooth surface and the more direct technical for the 3-D topological optimization of tooth surface.

Meshing Theory of ZC1 Worm Drive

2019 ◽  
Author(s):  
Yaping Zhao
Keyword(s):  
Gear Tooth ◽  
Worm Gear ◽  
Tooth Surface ◽  
Grinding Wheel ◽  
Normal Vector ◽  
Limit Function ◽  
Lubrication Performance ◽  
Working Length ◽  
Curvature Interference ◽  
Worm Drive

Abstract The toroidal enveloping cylindrical worm drive, also called the ZC1 worm drive, is grinded by the toroidal grinding wheel. In this paper, the meshing theory for this worm drive is systematically established. According to this meshing theory, the meshing function, the meshing limit function, the equations of the worm helicoid and the worm gear tooth surface are obtained. A method for computing the normal vector of the instantaneous line of the ZC1 worm pair is proposed. Due to this method, the curvature interference limit function and the meshing quality parameters can be more simply and clearly obtained. Based on above results, the methods of the numerical calculation of the instantaneous lines and the conjugate zone are proposed. The initial values of the nonlinear equation systems, computed the conjugate zone and the contact lines, are detected and solved by the method based on the elimination method and geometric construction. The results of numerical example clearly reflect that the conjugate zone can almost cover the whole tooth surface of the worm gear and the effective working length of the worm cannot nearly exceed the half of its thread length. The values of the induced principle curvature and the sliding angle show that the lubrication performance is poor and the stress level is higher, near the meshing limit line and at the dedendum of the worm gear.

Characteristics of a Modified Double Enveloping Worm Gear Drive

1992 ◽  
Author(s):  
Vilmos Simon
Keyword(s):  
Gear Tooth ◽  
Worm Gear ◽  
Performance Characteristics ◽  
Tooth Surface ◽  
Gear Teeth ◽  
Gear Drive ◽  
Load Distributions ◽  
Worm Gearing ◽  
Axial Profile ◽  
New Type

Abstract A modified new type of double enveloping worm gearing is developed. The gear tooth surface is generated by a flying tool whose cutting edge has the modified profile of the entering edge of the worm, and the worm surface has a straight-lined axial profile and circular lead changed to the established rule. The same rule governs the motion of the flying tool in processing the gear teeth. To compare the performance characteristics of the classical and the modified new type of double enveloping worm gearings, the load distributions are calculated and the elastohydrodynamic analysis of lubrication is carried out for both types of worm gearings. The obtained results show the advantages of the new type of double enveloping worm gear drive.

Multistep Method for Grinding Face-Gear by Worm

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Yuansheng Zhou ◽  
Jinyuan Tang ◽  
Heng Zhou ◽  
Feng Yin
Keyword(s):  
Theoretical Analysis ◽  
Mathematical Models ◽  
Gear Tooth ◽  
Original Method ◽  
Multistep Method ◽  
Tooth Surface ◽  
Contact Lines ◽  
Face Gear ◽  
Grinding Method ◽  
The Face

With the original worm grinding method to manufacture face-gear, the mathematical models of shaper, worm, and face-gear are established at the beginning. Subsequently, a problem of the original grinding method is illustrated that the working part of the face-gear tooth surface may not be covered completely. To overcome this problem, multistep grinding method for completely grinding the whole working part is proposed by studying contact lines of the tooth surface and singularities of the worm thread surface. The proposed method is verified in matlab with theoretical analysis. Finally, the simulations of the original method and the multistep method in the vericut software verify the feasibility and correctness of the proposed method. The study provides an effective and precise approach to grinding the face-gear.

Sign in / Sign up

Export Citation Format

Share Document