Geometry and contact characteristics of torus involute gears

Author(s):  
Lei Liu ◽  
Jingwen Tan ◽  
Meijuan Fang

Aimed at overcoming high sensitivity to machining or mounting error of line-contact conjugate surfaces, a novel torus involute gear drive is proposed which can compensate large axial misalignments and possess good meshing characteristics without lead correction. The torus involute gear is essentially a special spur gear with continuous shifting in the second order. Based on the processing principle of the torus involute gears, their mathematical models are established according to the corresponding imaginary rack cutter. In order to provide the approach to choose proper designing parameters, geometry characteristics of the torus involute gear are investigated: condition equations of tooth undercutting for a convex torus involute gear and tooth pointing for a concave torus involute gear are formulated utilizing the developed mathematical models, and the approach to checking tooth flank interference is provided. Contact characteristics of the gear set is studied through tooth contact analysis and finite element analysis. The simulated results produce useful information about tooth contact pattern, stress distribution, and transmission errors of the gear set.

Author(s):  
Yonghong Chen ◽  
Wenjun Luo ◽  
Yan Chen ◽  
Guanghui Zhang

In this paper, a novel multitooth point contact hourglass worm drive is proposed, which is composed of a planar enveloping hourglass worm and a spur involute gear, and both of them can be hardened and precisely ground. This novel hourglass worm drive is also named as involute gear meshing with planar enveloping hourglass worm drive (IP hourglass worm drive). Based on the gear geometry theory and the medium gear, the mathematical models of IP hourglass worm drive are deduced, the theory of tooth contact analysis is studied, as well as the tooth contact analysis is developed by the numerical analysis and finite element analysis. The performance of IP hourglass worm drive has been confirmed by the numerical simulation. This work is expected to give a theoretical basis for the IP hourglass worm drive.


Lubricants ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 20 ◽  
Author(s):  
Gajarajan Sivayogan ◽  
Ramin Rahmani ◽  
Homer Rahnejat

Energy efficiency and functional reliability are the two key requirements in the design of high-performance transmissions. Therefore, a representative analysis replicating real operating conditions is essential. This paper presents the thermoelastohydrodynamic lubrication (TEHL) of meshing spur gear teeth of high-performance racing transmission systems, where high generated contact pressures and lubricant shear lead to non-Newtonian traction. The determination of the input contact geometry of meshing pairs as well as contact kinematics are essential steps for representative TEHL. These are incorporated in the current analysis through the use of Lubricated Loaded Tooth Contact Analysis (LLTCA), which is far more realistic than the traditional Tooth Contact Analysis (TCA). In addition, the effects of lubricant and flash surface temperature rise of contacting pairs, leading to the thermal thinning of lubricant, are taken into account using a thermal network model. Furthermore, high-speed contact kinematics lead to shear thinning of the lubricant and reduce the film thickness under non-Newtonian traction. This comprehensive approach based on established TEHL analysis, particularly including the effect of LLTCA on the TEHL of spur gears, has not hitherto been reported in literature.


Author(s):  
V Spitas ◽  
C Spitas

Standard involute gear designs dominate high-power transmission applications because they combine sufficient bending strength with high pitting resistance, while retaining an adequate contact ratio. In this paper, a non-standard, optimal alternative involute gear design has been presented, which has the same pitting resistance as the standard involute gears but exhibits maximum resistance to bending. The optimization procedure is based on the complex algorithm, where the root stress, as calculated through tabulated boundary element analysis values, is the objective function and the active constraints include all of the kinematical, manufacturing and geometrical conditions, which must be satisfied by the optimal design, including the pitting resistance. The results indicate that optimal designs can achieve up to 8.5 per cent reduction of the fillet stress. Two-dimensional photoelasticity was used to verify the optimization results.


2010 ◽  
Vol 43 ◽  
pp. 279-282
Author(s):  
Kai Xu ◽  
Xiao Zhong Deng ◽  
Jian Jun Yang ◽  
Guan Qiang Dong

Based on Tooth Contact Analysis (TCA), a feasible approach for Transmission Error (TE) of planetary gear train is proposed in this paper. With a view to getting the total TE curve of the planetary gear train, a specific analysis of the TE from the planetary gear train with only one planet should be proceed firstly, the second step is to calculate each phase difference of planets in the gear train. The applicable conditions for the simplified calculation are spur gear or involute gear pairs in the gear train. Due to equal space between them, planets have the same phase angle.


2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Wei-Shiang Wang ◽  
Zhang-Hua Fong

This paper proposes a new type of double-crowned helical gear that can be continuously cut on a modern Cartesian-type hypoid generator with two face-hobbing head cutters and circular-arc cutter blades. The gear tooth flank is double crowned with a cycloidal curve in the longitudinal direction and a circular arc in the profile direction. To gauge the sensitivity of the transmission errors and contact patterns resulting from various assembly errors, this paper applies a tooth contact analysis technique and presents several numerical examples that show the benefit of the proposed double-crowned helical gear set. In contrast to a conventional helical involute gear, the tooth bearing and transmission error of the proposed gear set are both controllable and insensitive to gear-set assembly error.


2019 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
Callum Oglieve ◽  
Gajarajan Sivayogan ◽  
Homer Rahnejat ◽  
Mahdi Mohammadpour

2019 ◽  
Vol 8 (1) ◽  
pp. 23 ◽  
Author(s):  
Callum Oglieve ◽  
Gajarajan Sivayogan ◽  
Mahdi Mohammadpour ◽  
Homer Rahnejat

2010 ◽  
Vol 44-47 ◽  
pp. 3711-3715
Author(s):  
Rui Liang Zhang ◽  
Tie Wang ◽  
Hong Mei Li

Tooth contact analysis is an effective tool for meshing analysis of the double circular arc profile spiral bevel gear (DCAPSBG), as well as the basis for loading tooth contact analysis and finite element analysis. Applying the principle of tooth contact analysis (TCA) and the tooth profile characteristic of the DCAPSBG, this paper introduced and discussed the key contents and method of TCA computer programming for numerical simulation analysis of the transmission meshing quality of DCAPSBG. The TCA program developed in this paper, which had been verified by real examples, provided an effective approach for the design of DCAPSBG.


Author(s):  
Yi-Pei Shih ◽  
Bor-Tyng Sheen ◽  
Kun-Yu Wu ◽  
Jyh-Jone Lee

Cycloidal gear drives possess compact sizes, large reduction ratios, and low backlash. They are particularly suitable for applications in precise positioning and large output torque, for example, industrial robots and machine tools. Two main dynamic performances, transmission accuracy and backlash, is directly influenced by manufacturing errors. This paper aims to provide a direct method to effectively evaluate both performances. The mathematical models of transmission errors and backlash are established using the theory of gearing as well as tooth contact analysis. Three cases, considering profile modifications of the cycloidal gear and manufacturing errors, are evaluated to verify the correctness of the mathematical models.


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