Churning losses of spiral bevel gears at high rotational speed

2019 ◽  
Vol 234 (2) ◽  
pp. 172-182 ◽  
Author(s):  
R Quiban ◽  
C Changenet ◽  
Y Marchesse ◽  
F Ville ◽  
J Belmonte
Keyword(s):  
Rotational Speed ◽  
Local Maximum ◽  
Immersion Depth ◽  
Geometrical Parameters ◽  
Test Rig ◽  
Specific Test ◽  
High Rotational Speed ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel

In the present study, no-load losses of different splash lubricated spiral bevel gears were measured. The authors used a specific test rig, and a set of gears, to investigate churning losses at higher tangential speeds: up to 60 m/s. An uncommon behavior of the drag torque was highlighted: the torque increased with the rotational speed until a local maximum was reached; then the torque decreased and a local minimum was noticed; at higher rotational speed the torque increased. The torque decrease seems to be linked with a windage phenomenon, which becomes non-negligible at such speeds. In this work, efforts were made to characterize this reduction of gear immersion depth in order to be able to predict no-load losses. It was found that the evolution of oil immersion was linked to a Froude number. Finally a new analytical model of no-load losses was developed for churning losses combined with windage effects. This formulation takes into account several parameters such as rotational speed, gear immersion depth, oil properties, and gear geometrical parameters.

scholarly journals Experimental investigations and analysis on churning losses of splash lubricated spiral bevel gears

2017 ◽  
Vol 18 (4) ◽  
pp. 412 ◽  
Author(s):  
S. Laruelle ◽  
C. Fossier ◽  
C. Changenet ◽  
F. Ville ◽  
S. Koechlin
Keyword(s):  
Experimental Tests ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Spiral Bevel Gear ◽  
Power Losses ◽  
Test Rig ◽  
Specific Test ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel

Churning losses are a complex phenomenon which generates significant power losses when considering splash lubrication of gear units. However, only few works deal with bevel gears dipped lubrication losses. The objective of this study is to provide a wide variety of experimental tests on churning losses, especially getting interested in geometry of spiral bevel gears influence. A specific test rig was used in order to study a single spiral bevel gear partially immersed in an oil bath. Experiments have been conducted for several operating conditions in terms of speeds, lubricants, temperatures and gear geometries to study their impact on splash lubrication power losses. These experimental results are compared with the predictions from various literature sources. As the results did not agree well with the predictions for all operating conditions, an extended equation derived from previous works is introduced to estimate churning losses of bevel gears.

The Scuffing Resistance of WC/C Coated Spiral Bevel Gears

2014 ◽  
Vol 604 ◽  
pp. 36-40 ◽  
Author(s):  
Remigiusz Michalczewski ◽  
Marek Kalbarczyk ◽  
Waldemar Tuszynski ◽  
Marian Szczerek
Keyword(s):  
Bevel Gear ◽  
Spiral Bevel Gear ◽  
Test Rig ◽  
Low Friction ◽  
Spiral Bevel Gears ◽  
Gear Teeth ◽  
Bevel Gears ◽  
Trade Name ◽  
Gear Oil ◽  
Spiral Bevel

One of the main problems with the operation of spiral bevel gears is related to very severe conditions in the contact of the meshing teeth; therefore, lubrication is very difficult, which increases the risk of scuffing occurrence. One of the ways to achieve better scuffing resistance is by the deposition of a low-friction coating on the bevel gears teeth. Gear scuffing tests were performed using a bevel gear test rig designed and manufactured at ITeE-PIB. The authorial bevel gear scuffing test was performed. Specially designed, spiral bevel gears were used for testing. Two material combinations were tested: uncoated pinion - coated wheel and, for reference, both gears without coatings. The a-C:H:W (trade name WC/C) coating of DLC type was deposited on the wheel teeth. A mineral, automotive gear oil of API GL-5 performance level was used for lubrication. It is shown that the resistance to scuffing may be significantly improved when the a-C:H:W coating is deposited on the spiral bevel gear teeth.

scholarly journals Testing of the Resistance to Scuffing of Spiral Bevel Gears: Test Rig, Method, and Results of Verification Testing

2019 ◽  
Author(s):  
Waldemar Tuszynski ◽  
Marek Kalbarczyk ◽  
Bartosz Kiser ◽  
Michal Michalak ◽  
Remigiusz Michalczewski ◽  
...  
Keyword(s):  
Test Rig ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Spiral Bevel

Churning power loss of the intermediate gearbox in a helicopter under splash lubrication

2021 ◽  
pp. 135065012110100
Author(s):  
Fengxia Lu ◽  
Meng Wang ◽  
Heyun Bao ◽  
Wei Huang ◽  
Rupeng Zhu
Keyword(s):  
Rotational Speed ◽  
Power Loss ◽  
Flow Model ◽  
Input Power ◽  
Immersion Depth ◽  
Two Phase ◽  
Bevel Gears ◽  
Oil Immersion ◽  
Simulation Results ◽  
Spiral Bevel

Based on computational fluid dynamics, a two-phase flow model was established to calculate the churning power loss of the spiral bevel gears under splash lubrication. The error between the simulation results and experiment results is only 7.04%. Taking a certain helicopter as an example, the churning power loss of the intermediate gearbox is ∼2.6051 kW, accounting for ∼1.93% of the input power. Besides, the motion mechanisms of free flow, ejection flow and splashing flow of the spiral bevel gear were investigated. The influences of the rotational speed and oil immersion depth on the churning power loss were analysed. The rotational speed and oil immersion depth of the intermediate gearbox should be in the range of 3000–5000 r/min and 17–26 mm, respectively, which can ensure sufficient lubrication and low churning power loss.

scholarly journals Contact stiffness and damping of spiral bevel gears under transient mixed lubrication conditions

Friction ◽  
2021 ◽  
Author(s):  
Zongzheng Wang ◽  
Wei Pu ◽  
Xin Pei ◽  
Wei Cao
Keyword(s):  
Contact Stiffness ◽  
Mixed Lubrication ◽  
Asperity Contact ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Dry Contact ◽  
Spiral Bevel ◽  
Stiffness And Damping ◽  
Lubrication Conditions ◽  
Film Lubrication

AbstractExisting studies primarily focus on stiffness and damping under full-film lubrication or dry contact conditions. However, most lubricated transmission components operate in the mixed lubrication region, indicating that both the asperity contact and film lubrication exist on the rubbing surfaces. Herein, a novel method is proposed to evaluate the time-varying contact stiffness and damping of spiral bevel gears under transient mixed lubrication conditions. This method is sufficiently robust for addressing any mixed lubrication state regardless of the severity of the asperity contact. Based on this method, the transient mixed contact stiffness and damping of spiral bevel gears are investigated systematically. The results show a significant difference between the transient mixed contact stiffness and damping and the results from Hertz (dry) contact. In addition, the roughness significantly changes the contact stiffness and damping, indicating the importance of film lubrication and asperity contact. The transient mixed contact stiffness and damping change significantly along the meshing path from an engaging-in to an engaging-out point, and both of them are affected by the applied torque and rotational speed. In addition, the middle contact path is recommended because of its comprehensive high stiffness and damping, which maintained the stability of spiral bevel gear transmission.

Deformations and Stresses in Face-Hobbed Spiral Bevel Gears

2011 ◽  
Author(s):  
Vilmos V. Simon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Nodal Point ◽  
Design Parameters ◽  
Element Discretization ◽  
Spiral Bevel Gears ◽  
Bevel Gears ◽  
Tooth Surfaces ◽  
Spiral Bevel ◽  
Element Method

In this study an attempt is made to predict displacements and stresses in face-hobbed spiral bevel gears by using the finite element method. A displacement type finite element method is applied with curved, 20-node isoparametric elements. A method is developed for the automatic finite element discretization of the pinion and the gear. The full theory of the generation of tooth surfaces of face-hobbed spiral bevel gears is applied to determine the nodal point coordinates on tooth surfaces. The boundary conditions for the pinion and the gear are set automatically as well. A computer program was developed to implement the formulation provided above. By using this program the influence of design parameters and load position on tooth deflections and fillet stresses is investigated. On the basis of the results, obtained by performing a big number of computer runs, by using regression analysis and interpolation functions, equations for the calculation of tooth deflections and fillet stresses are derived.

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