scholarly journals Application of Face-Gear Drives in Helicopter Transmissions

Author(s):  
F. L. Litvin ◽  
J.-C. Wang ◽  
R. B. Bossler ◽  
Y.-J. D. Chen ◽  
G. Heath ◽  
...  

Abstract The use of face gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face gears was described. Face-gear design and geometry were investigated. Topics included tooth generation, limiting inner and outer radii, tooth contact analysis, contact ratio, gear eccentricity, and structural stiffness. Design charts were developed to determine minimum and maximum face-gear inner and outer radii. Analytical study of transmission error showed face-gear drives were relatively insensitive to gear misalignment, but tooth contact was affected by misalignment. A method of localizing bearing contact to compensate for misalignment was explored. The proper choice of shaft support stiffness enabled good load sharing in the split torque transmission design. Face-gear experimental studies were also included and the feasibility of face gears in high-speed, high-load applications such as helicopter transmissions was demonstrated.

1994 ◽  
Vol 116 (3) ◽  
pp. 672-676 ◽  
Author(s):  
F. L. Litvin ◽  
J.-C. Wang ◽  
R. B. Bossler ◽  
Y.-J. D. Chen ◽  
G. Heath ◽  
...  

The use of face-gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face-gears was described. Face-gear design is discussed. Topics included basic design geometry, tooth generation, limiting inner and outer radii, and recommendation for the gear ratio. Face-gear experimental studies were also included and the feasibility of face-gears in high-speed, high-load applications such as helicopter transmissions was demonstrated. Torque-split tests were performed and demonstrated an accurate split of torque using the face-gear concept.


1997 ◽  
Vol 119 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Y. Zhang ◽  
Z. Wu

This paper presents a detailed investigation on the manufacturing, tooth geometry and contact characteristics of face gear drives with offset axes. In the paper, the tooth geometry of offset face gears is analytically determined by simulating the conjugate motion between the gear and the cutting tool in the generation process. Design criteria are established for the optimal tooth element proportions of offset face gears that avoid tooth undercutting and pointing. The tooth surface geometry of the gear member of the drive is modified by using a shaper that resembles the pinion in profile but has a few more teeth than the pinion to localize the tooth contact. The contact characteristics of the offset face gears are analyzed by a tooth contact analysis (TCA) program that simulates the meshing process of the gear drive assembled under misalignment. An example of offset face gear design and contact analysis is included in the paper.


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.


2000 ◽  
Vol 42 (3) ◽  
pp. 487-502 ◽  
Author(s):  
Shuo-Hung Chang ◽  
Tsang-Dong Chung ◽  
Shui-Shong Lu

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110099
Author(s):  
Dong Hao ◽  
Zhang Hao-qin ◽  
Zhao Xiao-long ◽  
Duan Ling-ling

In order to solve the load-sharing characteristics of face-gear four-branching split-torque transmission system (FGFBSTTS), the static load-sharing mechanical analysis model was established. In the model, the deformation coordination conditions of torsional angle and torque balance condition were considered. By using Loaded Tooth Contact Analysis (LTCA) technology of face gear and herringbone gear, the time-varying meshing stiffness was calculated. The influences of manufacturing errors, installation errors, I-stage pinion floating, II-stage pinion spline clearance floating, and radial limit ring clearance floating on the load-sharing characteristics are analyzed. The results show that the LTCA technology is more accurate to reflect the load-sharing characteristics of each meshing position. When the I-stage pinion and the II-stage pinion floated at the same time, the best load-sharing characteristics can be obtained. The load-sharing characteristics affected by manufacturing errors showed obvious periodic change. The radial limit ring plays a better auxiliary role in load-sharing characteristics. The theoretical results were compared with the experiments to verify the correctness of the theoretical analysis. The research results can provide a theoretical basis for the optimal design of the load-sharing structure, error control, and assembly of the face gear four branch transmission system.


2010 ◽  
Vol 139-141 ◽  
pp. 1154-1157 ◽  
Author(s):  
Hui Guo ◽  
Ning Zhao ◽  
Hao Gao

This paper proposes a modification method for tooth surface of face gear drive with a grinding worm on a numerical grinding machine. The surface equation of grinding worm is derived, and the coordinate System of generating the worm is established. Tooth contact analysis (TCA) is performed to investigate the performance of face gear drive before and after modification, and the alignment error is considered. This method can obtain a more stable bearing contact in contrast to the method by increasing tooth number of shaper. The longitudinal bearing contact on the face-gear tooth surface has been obtained which will increase the contact ratio. By modification the edge contact at surface edges of the gears can be avoided and the modification magnitude can be controlled freely.


2009 ◽  
Vol 131 (8) ◽  
Author(s):  
Yi-Cheng Wu ◽  
Kuan-Yu Chen ◽  
Chung-Biau Tsay ◽  
Yukinori Ariga

In this paper, the circular-arc curvilinear tooth gear drive is proposed. The gear and pinion tooth surfaces are generated by two complemented circular-arc rack cutters with curvilinear tooth-traces. According to the theory of gearing, the mathematical model of the proposed gear is developed. The tooth contact analysis technique is utilized to investigate the kinematical errors of circular-arc curvilinear tooth gear drives under different assembly errors. Contact patterns of the circular-arc curvilinear tooth gear drive are simulated by the developed computer-aided tooth contact analysis programs and surface topology method. Numerical examples are presented to show the kinematical errors of the circular-arc curvilinear tooth gear set under different assembly conditions. Relations among the circular-arc tooth profile, curvilinear tooth-trace, contact ratio, contact pattern, and kinematical error are also demonstrated by numerical examples.


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.


Author(s):  
Mircea Napau ◽  
Ileana D. Napau ◽  
Ioan Napau ◽  
Vistrian Maties ◽  
Ana A. Napau-Stoica ◽  
...  

The virtual simulation methods used in the gear industry allow for the prediction of requirements in the gears manufacturing process, as well as, prediction of their mesh before they are manufactured. The aim of this paper is to present an approach regarding the virtual simulation of multi-tooth contact analysis of worm-face gear drives used in the automotive industry. The methods presented in this paper are intended to reduce the process development phase of gearboxes, having as components, worm-face gear drives and thus saving large amounts of time and money. A procedure has been developed in order to simulate the idle multi-tooth contact, in a worm-face gear drive with localized contact, as a combinative algorithm of using a virtual manufacturing method and the power of MathCAD software. Virtual simulation of loaded multi-tooth contact analysis has been carried out together with the contact stress analysis by FEA method using ANSYS software. The FEM models have been developed by Computer Manufacturing Simulation (CMS) method. 3D CAD examples illustrating the idle contact pattern on face gear teeth flanks are presented for both directions of rotation of the driving worm. Numerical results related to the loaded multi-tooth contact analysis and contact stress analysis, respectively, are also provided in order to illustrate the developed approach.


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