The Mechanical Efficiency of Epicyclic Gear Trains

1993 ◽  
Vol 115 (3) ◽  
pp. 645-651 ◽  
Author(s):  
E. Pennestri` ◽  
F. Freudenstein

The analysis of mechanical efficiency constitutes an important phase in the design analysis of gear drives. The objective of this investigation has been the development of a general algorithm for the determination of efficiency in split-power spur-gear trains. The model includes meshing losses only; for a more realistic estimation other sources can be considered separately. The systematic nature of the formulation, based on the dual correspondence between the kinematic structure of the gear drive and a labelled graph, allows a ready coding of the efficiency analysis in a general computer program. The numerical results are in line with those given by other authors using different methodologies.

2003 ◽  
Vol 125 (3) ◽  
pp. 602-608 ◽  
Author(s):  
Ettore Pennestrı` ◽  
Pier Paolo Valentini

This paper, after a rigorous proof of the formulas originally proposed by Radzimovsky, demonstrates the numerical equivalence of the different approaches available for computing the mechanical efficiency of two degrees-of-freedom (d.o.f.) epicyclic gear trains. The paper includes also a discussion on the redundancy of data required by some formulas.


1978 ◽  
Vol 48 ◽  
pp. 287-293 ◽  
Author(s):  
Chr. de Vegt ◽  
E. Ebner ◽  
K. von der Heide

In contrast to the adjustment of single plates a block adjustment is a simultaneous determination of all unknowns associated with many overlapping plates (star positions and plate constants etc. ) by one large adjustment. This plate overlap technique was introduced by Eichhorn and reviewed by Googe et. al. The author now has developed a set of computer programmes which allows the adjustment of any set of contemporaneous overlapping plates. There is in principle no limit for the number of plates, the number of stars, the number of individual plate constants for each plate, and for the overlapping factor.


2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Essam Lauibi Esmail

The concept of potential power efficiency is introduced as the efficiency of an epicyclic gear train (EGT) measured in any moving reference frame. The conventional efficiency can be computed in a carrier-moving reference frame in which the gear carrier appears relatively fixed. In principle, by attaching the reference frame to an appropriate link, torques can be calculated with respect to each input, output, or (relatively) fixed link in the EGT. Once the power flow direction is obtained from the potential power ratio, the torque ratios are obtained from the potential power efficiencies, the particular expression of the efficiency of the EGT is found in a simple manner. A systematic methodology for the efficiency analysis of one and two degree-of-freedom (DOF) EGTs is described, and 14 ready-to-use efficiency formulas are derived for 2DOF gear pair entities (GPEs). This paper includes also a discussion on the redundancy of the efficiency formulas used for 1DOF GPEs. An incomplete in the efficiency formulas in previous literature, which make them susceptible to wrong application, is brought to light.


Author(s):  
V. Roda-Casanova ◽  
F. Sanchez-Marin ◽  
J. L. Iserte

Gear misalignments originate unwanted uneven load distributions that increase contact pressures and the bending stresses, reducing the service life of gear drives. Therefore, it is very important to take into account the misalignments in the determination of contact pressures when designing a gear transmission. Some of these misalignments are related to manufacturing and assembly errors, but others are produced by the deformation of the shafts when power is transmitted. These deformations cause misalignment of the gears, modifying the contact bearing and the pressure distribution, which modifies the deformation of the shafts, leading to a coupled problem not always easy to solve. In this work, a new approach to solve this problem is proposed, based on an iterative algorithm which uncouples the determination of the deformation of the shafts from the contact problem. The proposed approach has been tested through various configurations of spur gear drives. The obtained results are compared with those obtained using a finite element model, showing a good correlation between them, but with a significant reduction of the computational cost.


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]


2015 ◽  
Vol 799-800 ◽  
pp. 570-575
Author(s):  
Zheng Min Qing Li ◽  
Qing Bin Zhao ◽  
Xiao Zhen Li

In this study, a mesh stiffness model of spur gear drives considering the tooth corrosion effect, which is based on Ishikawa model, is proposed. The fidelity of mesh stiffness based on the proposed model is checked by comparing the result with a benchmark result from the reference and the effect of the tooth corrosion on mesh stiffness is analyzed. The prediction indicates mesh stiffness is insensitive to the tooth corrosion, but this conclusion has a signification for assessing the stability of inherent properties of a spur gear drive when the tooth corrosion is produced.


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.


1981 ◽  
Vol 103 (1) ◽  
pp. 89-101 ◽  
Author(s):  
F. L. Litvin ◽  
Y. Gutman

The second article part is devoted to the calculation of machine settings for Hypoid gear-drive pinions being generated by “Formate” and “Helixform” cutting methods. The solution is based on a local synthesis method by following assumptions: (1) the member-gear surfaceΣ2 is given (the surface Σ2 becomes known after the determination of its machine settings, see article part 1): (2) the being obtained machine settings for the pinion must guarantee: (a) that the member-gear surface Σ2 will be in contact with the pinion surface Σ1 at a choosen point M, (b) that at M and in the vicinity of M prescribed conditions of meshing will be provided.


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