An Ease-Off Based Method for Loaded Tooth Contact Analysis of Hypoid Gears Having Local and Global Surface Deviations

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
M. Kolivand ◽  
A. Kahraman

Actual hypoid gear tooth surfaces do deviate from the theoretical ones either globally due to manufacturing errors or locally due to reasons such as tooth surface wear. A practical methodology based on ease-off topography is proposed here for loaded tooth contact analysis of hypoid gears having both local and global deviations. This methodology defines the theoretical pinion and gear tooth surfaces from the machine settings and cutter parameters, and constructs the surfaces of the theoretical ease-off and roll angle to compute for the unloaded contact analysis. This theoretical ease-off topography is modified based on tooth surface deviations and is used to perform a loaded tooth contact analysis according to a semi-analytical method proposed earlier. At the end, two examples, a face-milled hypoid gear set having local deviations and a face-hobbed one having global deviations, are analyzed to demonstrate the effectiveness of the proposed methodology in quantifying the effect of such deviations on the load distribution and the loaded motion transmission error.

2013 ◽  
Vol 341-342 ◽  
pp. 572-576 ◽  
Author(s):  
Jin Fu Du ◽  
Zong De Fang ◽  
Min Xu ◽  
Xing Long Zhao ◽  
Yu Min Feng

The geometry of the tooth surface is important for tooth contact analysis, load tooth contact analysis and the ease-off of gear pairs. This paper presents a mathematical model for the determination of the tooth geometry of Klingelnberg face-hobbed hypoid gears. The formulation for the generation of gear and pinion tooth surfaces and the equations for the tooth surface coordinates are provided in the paper. The surface coordinates and normal vectors are calculated and tooth surfaces and 3D tooth geometries of gear and pinion are obtained. This method may also applied to other face-hobbing gears.


Author(s):  
M. Kolivand ◽  
A. Kahraman

Manufacturing errors typically cause real (measured) spiral bevel and hypoid gear surfaces to deviate from the theoretical ones globally. Tooth surface wear patterns accumulated through the life span of the gear set are typically local deviations that are aggravated especially in case of edge contact conditions. An accurate and practical methodology based on ease-off topography is proposed in this study to perform loaded tooth contact analysis of spiral bevel and hypoid gears having both types of local and global deviations. It starts with definition of the theoretical pinion and gear tooth surfaces from the machine settings and cutter parameters, and constructs the theoretical ease-off and roll angle surfaces to compute unloaded contact analysis. Manufacturing errors and localized surface wear deviations are considered to update the theoretical ease-off to form a new ease-off surface that is used to perform a loaded tooth contact analysis according to the semi-analytical method proposed earlier. At the end, a numerical example with locally deviated surfaces is analyzed to demonstrate the effectiveness of the proposed methodology as well as quantifying the effect of such deviations on load distribution and the loaded motion transmission error.


2000 ◽  
Vol 122 (1) ◽  
pp. 109-122 ◽  
Author(s):  
Claude Gosselin ◽  
Thierry Guertin ◽  
Didier Remond ◽  
Yves Jean

The Transmission Error and Bearing Pattern of a gear set are fundamental aspects of its meshing behavior. To assess the validity of gear simulation models, the Transmission Error and Bearing Pattern of a Formate Hypoid gear set are measured under a variety of operating positions and applied loads. Measurement data are compared to simulation results of Tooth Contact Analysis and Loaded Tooth Contact Analysis models, and show excellent agreement for the considered test gear set. [S1050-0472(00)00901-6]


Author(s):  
Li-Chi Chao ◽  
Chung-Biau Tsay

The spherical gear is a new type of gear proposed by Mitome et al. [1]. Different from that of the conventional spur or helical gear sets, the spherical gear set can allow variable shaft angles and large axial misalignments without gear interference during the gear drive meshing [1, 2]. Geometrically, the spherical gear has two types of gear tooth profiles, the concave tooth and convex tooth. In practical transmission applications, the contact situation of a spherical gear set is very complex. To obtain a more realistic simulation result, the loaded tooth contact analysis (LTCA) has been performed by employing the finite element method (FEM). According to the derived mathematical model of spherical gear tooth surfaces, an automatic meshes generation program for three-dimensional spherical gears has been developed. Beside, tooth contact analysis (TCA) of spherical gears has been performed to simulate the contact points of the spherical gear set. Furthermore, the contact stress contours of spherical gear tooth surfaces and bending stress of tooth roots have been investigated by giving the design parameters, material properties, loadings and boundary conditions of spherical gears.


2013 ◽  
Vol 572 ◽  
pp. 351-354
Author(s):  
Simon Vilmos

In this study, an optimization methodology is proposed to systematically define head-cutter geometry and machine tool settings to introduce optimal tooth modifications in face-hobbed hypoid gears. The goal of the optimization is to simultaneously minimize tooth contact pressures and angular displacement error of the driven gear, while concurrently confining the loaded contact pattern within the tooth boundaries. The proposed optimization procedure relies heavily on a loaded tooth contact analysis for the prediction of tooth contact pressure distribution and transmission errors. The objective function and the constraints are not available analytically, but they are computable, i.e., they exist numerically through the loaded tooth contact analysis. The core algorithm of the proposed nonlinear programming procedure is based on a direct search method. Effectiveness of this optimization was demonstrated by using a face-hobbed hypoid gear example. Considerable reductions in the maximum tooth contact pressure and in the transmission errors were obtained.


Author(s):  
Caichao Zhu ◽  
Haixia Wang ◽  
Mingyong Liu ◽  
Xuesong Du ◽  
Chaosheng Song

Beveloid gears are widely applied in fields like ships, automobiles and industrial precision transmissions. In this paper, the formulas of the beveloid gear tooth surface used in marine transmissions were derived and a mesh model for the intersected beveloid gear pair was setup. Then loaded tooth contact analysis was performed using the finite element method considering the coupling of the assembly errors and the elastic deformation of tooth surface. Through the analysis, the influences of assembly errors on contact patterns, mesh force and tooth surface deformations were investigated. In a further step, the tooth profile modifications were performed to alleviate the edge contact and a subsequent major improvement of the mesh condition was obtained. Finally, loaded tooth contact experiments for marine gearboxes with small shaft angle were conducted. The tested results showed good correlation with the computed results. This work may provide some value for the practical design aiming at improved contact characteristics of the beveloid gears with intersected axes.


Author(s):  
J-L Li ◽  
S-T Chiou

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.


Author(s):  
Yan-zhong Wang ◽  
Can-hui Wu ◽  
Kang Gong ◽  
Shu Wang ◽  
Xing-fu Zhao ◽  
...  

In order to analyze the transmission performance of face-gear in real working condition, a calculational approach for load equivalent error of alignment has been investigated with the purpose of analyzing the support system and tooth deformation of face-gear drives. Then, the equations of contact path of loaded tooth contact analysis have been established based on load equivalent error of alignment. For the purpose of analyzing the bearing contact, the curvatures of face-gear and pinion have been presented. Tooth contact deformation and bending deformation have been developed using elasticity and three-dimensional FEA. Loaded tooth contact analysis and contact stress have been considered to simulate the contact and meshing of the gear tooth surfaces and to calculate the evolution of load distribution, bearing contact, transmission errors, and contact stresses of the gear drive along the cycle of meshing. The performed research proves that the proposed loaded tooth contact analysis method can effectively solve the meshing characteristic problem of face-gear drives system. The results are illustrated with numerical examples.


2021 ◽  
Author(s):  
Shunxing Wu ◽  
Hongzhi Yan ◽  
Zhiyong Wang ◽  
Rengui Bi ◽  
Jia Li

Abstract For the hypoid gear pair of the heavy-duty vehicle drive axle machined by the duplex helical method, in order to avoid edge contact and stress concentration on the tooth surface, a four-segment tool profile is designed to modify the concave and convex surfaces simultaneously. First, the geometric model of the four-segment tool profile is established. Second, the mathematical model of the duplex helical method based on the four-segment tool profile is established, and the method of solving the tooth surface generated by the connecting points of the four-segment tool profile is given. Finally, the finite element method of loaded tooth contact analysis is used to analyze the meshing performance of the gear pair obtained by the four-segment tool profile modification, and the results are compared with the original gear pair. The results show that after the tooth surfaces are modified, the edge contact of the tooth surfaces are avoided, the stress distribution of the tooth surfaces are improved, the maximum contact stress of the tooth surfaces are reduced, and the fatigue and wear life of the tooth surface are improved.


2012 ◽  
Vol 479-481 ◽  
pp. 944-948 ◽  
Author(s):  
Dian Hua Chen ◽  
Zhong Wei Zhang

A practical method based on normal gaps topography is proposed here for loaded tooth contact analysis of WN gear having tooth surface deviations. The simulation of meshing state and tooth strength of WN gear are provided with real tooth surfaces. In the study normal gaps distribution is adopted to calculate tooth surface contact elastic deformation and local deviations due to manufacturing errors and tooth surface wear. For WN gear, the loaded distribution on the contact zone in meshing tooth surface has not been investigated because of their complexity in the contact state. The finite element method is adopted to analyze the contact pattern and tooth strength. The study has concretely calculated the contact pressure and zone of meshing in different loaded and transmission error. At the end examples are analyzed to demonstrate the effectiveness of the proposed method in quantifying effect of such deviations on the loaded distribution and tooth stress distribution.


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