Influence of Misalignments on EHD Lubrication in Hypoid Gears

Author(s):  
Vilmos V. Simon

The thermal elastohydrodynamic analysis of lubrication is applied to investigate the influence of misalignments of the meshing members on EHD lubrication in hypoid gears. The calculation is based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The full thermal EHD lubrication analysis is applied, therefore, the oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. The real shape of the gap existing between the contacting tooth surfaces is treated, based on gear teeth geometry defined by the gear processing method and including the misalignments of mating members. By using the corresponding computer program, the influence of pinion’s running offset and axial adjustment errors, and angular position error of pinion axis on maximum oil film pressure and temperature, EHD load carrying capacity, and on power losses in the oil film is investigated. The obtained results are presented and discussed.

Author(s):  
Vilmos V. Simon

The influence of lubricant characteristics and operating parameters on the elastohydrodynamic lubrication in hypoid gears is investigated. The full thermal elastohydrodynamic analysis of lubrication is applied, based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. Using a computer algorithm, the influence of oil viscosity, pressure-viscosity and temperature-viscosity exponents, supplied oil temperature, speed and minimum oil film thickness on maximum oil film pressure and temperature, EHD load carrying capacity, and power losses in the oil film is investigated. The obtained results are presented and discussed.


Author(s):  
Vilmos Simon

The full thermal EHD lubrication analysis is applied, therefore, the oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. By using the corresponding computer program, the influence of oil viscosity, pressure-viscosity and temperature-viscosity exponents, supplied oil temperature, speed and minimum oil film thickness on maximum oil film pressure and temperature, EHD load carrying capacity, and on power losses in the oil film is investigated. Small part of the obtained results is presented and discussed.


1997 ◽  
Vol 119 (1) ◽  
pp. 101-107 ◽  
Author(s):  
V. Simon

A full thermal elastohydrodynamic analysis of lubrication of a new type of cylindrical worm gearing with concave worm profile, ground by a grinding wheel whose profile consists of two circular arcs, is presented. The EHD lubrication analysis is based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. The finite difference method and numerical integration have been used to get the solution of the highly nonlinear integrodifferential system of governing equations. By using a computer program, the influence of design and operating parameters of the new type of worm gearing on EHD lubrication characteristics has been investigated. Also, the comparison of the EHD load carrying capacity and of the power losses in the oil film of the new type and of the commonly used cylindrical worm gearings has been carried out.


Author(s):  
Vilmos Simon

The thermal elastohydrodynamic analysis of lubrication is applied to investigate the influence of misalignments of the meshing members on lubrication in spiral bevel gears. The calculation is based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The full thermal EHD lubrication analysis is applied, therefore, the oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. By using the corresponding computer program, the influence of pinion’s running offset and axial adjustment errors, and angular position error of pinion axis on maximum oil film pressure and temperature, EHD load carrying capacity, and on power losses in the oil film is investigated. On the basis of the obtained results it can be concluded that the EHD load carrying capacity and the friction factor are very sensitive to misalignments of the mating members in the spiral bevel gear pair, the friction factor is reduced by the increase of EHD load carrying capacity and vise versa, and the maximum inlet oil temperature is almost insensitive to the misalignments.


2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Vilmos V. Simon

In this study, an optimization methodology is proposed to systematically define the optimal tooth modifications introduced by head-cutter geometry and machine-tool settings to minimize the influence of misalignments on the elastohydrodynamic (EHD) lubrication characteristics in face-hobbed spiral bevel gears. The goal is to simultaneously maximize the EHD load-carrying capacity of the oil film and to minimize power losses in the oil film when different misalignments are inherent in the gear pair. The proposed optimization procedure relies heavily on the EHD lubrication analysis developed in this paper. The core algorithm of the proposed nonlinear programming procedure is based on a direct search method. Effectiveness of this optimization was demonstrated on a face-hobbed spiral bevel gear example. A drastic increase in the EHD load-carrying capacity of the oil film and a reduction in the power losses in the oil film were obtained.


1982 ◽  
Vol 25 (205) ◽  
pp. 1164-1172
Author(s):  
Shoji HAIZUKA ◽  
Chotaro NARUSE ◽  
Ryozo NEMOTO ◽  
Satoshi SAKURAI

Author(s):  
B.-R. Höhn ◽  
H. Winter ◽  
K. Michaelis ◽  
F. Vollhüter

Abstract Bevel and hypoid gears are widely used for gears with crossed axis. The influence of a pinion offset on the load carrying capacity — pitting resistance and bending strength — is introduced in a different way in commonly used calculation methods. Load carrying and measurement investigations on the influence of pinion offset on pitting resistance and bending strength are reported. Tests show an increasing bending strength and decreasing maximum tooth root stresses with increasing pinion offset. Also a slight increase of pitting resistance and a slight decrease of the Hertzian pressure was evaluated. The load carrying calculation results for bevel gears without pinion offset, DIN 3991, is in good agreement with test results. The bending strength of hypoid gears calculated according to Niemann/Winter, is greater than that experimentally measured. For pitting resistance, however, the calculation is less than the measured results.


1988 ◽  
Vol 110 (4) ◽  
pp. 699-703 ◽  
Author(s):  
Awny Y. Attia ◽  
Ahmed M. M. El-Bahloul

The paper presents the results of an experimental investigation carried out at Mansoura University Laboratories aiming at studying the effect of change of speed, oil viscosity, and helix angle on the load carrying capacity of the oil film. A three pairs of test gears of 6 DP, 91.5 mm pitch diameter with 22.3, 33.6 and 42.25 deg helix angles were run in power circulating test rig at 100 to 3000 r.p.m. speeds and transmitting tooth load ranging from 185 to 1090 Kp. The test gears were lubricated with oils of 200, 462, and 653 cSt at 40°C kinematic viscosities. The oil film thicknesses between contacting teeth were measured by measuring the changes in capacitance between test gears and transferred to linear dimensions by calibration curves drawn by knowing the changes in capacitance through the gaps between teeth of values known through the amount of backlash. The experimental results show that; Oil film thickness decreases with tooth load, while increases with speed and viscosity of the lubricant. Oil film thickness versus helix angle give an inversed parabola for the smallest and medium tooth loads, while oil film thickness decreases with increasing the helix angle under increased tooth loads. Load carrying capacity increases with speeds and viscosity of the lubricant while decreases with increasing the helix angle.


1988 ◽  
Vol 110 (3) ◽  
pp. 330-336 ◽  
Author(s):  
V. Simon

The full thermal elastohydrodynamic analysis of lubrication of helical gears is presented. A numerical solution of the coupled Reynolds, elasticity, energy, and Laplace’s equations for the oil film shape, pressure and temperature distributions in the oil film, and temperature distribution in gear teeth is obtained. The effects of gear parameters and operating conditions on EHD performance characteristics is discussed. Based on the obtained results, by regression analysis, equations are derived to calculate the EHD load carrying capacity, maximum oil temperature, and power loss.


1981 ◽  
Vol 103 (1) ◽  
pp. 195-203 ◽  
Author(s):  
V. Simon

The full thermal elastohydrodynamic analysis of the lubrication of hypoid gears is presented. A numerical solution of the coupled Reynolds, elasticity and energy equations for the pressure, temperature and film thickness is obtained. The temperature variations across the oil film and in the pinion and gear teeth are included. The real tooth geometry of the modified hypoid gears is treated. The effect of the operating conditions on the performance characteristics is discussed.


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