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This paper aims to establish a prediction model of stable transmission time of spiral bevel gear during a loss-of-lubrication event in helicopter transmission system.

To observe the temperature change of spiral bevel gear during working condition, a test rig of spiral bevel gear was developed according to the requirements of experiments and carried out verification experiments.

The prediction is verified by the test of detecting the temperature of oil pool. The main damage form of helicopter spiral bevel gears under starved lubrication is tooth surface burn. The stable running time under oil-free lubrication is mainly determined by the degree of tooth surface burn control.

The experimental data of the spiral bevel gear oil-free lubrication process are basically consistent with the simulation prediction results. The results lay a foundation for the working life design of spiral bevel gear in helicopter transmission system under starved lubrication.

This paper aims to create an application to support spiral bevel gear contact pattern verification in the computer aided design (CAD) system to speed up the selection of technological setups for the cutting machine by finding these in the virtual environment at the design level.

This paper presents an application which has been created to simulate a pattern check on spiral bevel gears in the virtual environment. The pattern check is conducted on the CAD models obtained from the cutting simulation in the CAD system using technological settings calculated by the KONTEPS system. Check of the contact pattern in the virtual environment works in the same way as in the real production process. The application has been written in C# programming language and run in the NX open environment in the UG NX.

This paper shows the possibilities of how the CAD system can be used at the design level of spiral bevel gears to verify an unloaded tooth contact pattern position for applied technological setups for dedicated cutting machine.

This paper describes an application that has the possibility to be implemented in small companies which produce small lots of gear sets and help to decrease the time for setting a cutting machine.

This paper addresses the needs to find new technologies to improve the design process of the spiral bevel gears.

The purpose of this paper is to present the use of a CAD system for the analysis of meshing of spiral bevel gears.

The TCA computer programs are based on a purely mathematical model and require to get the numerical solution of a set of nonlinear equations. There are situations that the programs fail to obtain the proper solution. In such cases, geometrical gear models defined in CAD environment prove to be a good choice. This paper describes a tool for analyzing tooth contact and transmission errors of spiral bevel gear sets with tooth flanks represented as CAD free-form surfaces.

A new method has been proposed to keep those surfaces in continuous contact in the whole range of meshing of a mating tooth pair. During meshing, the points of contact as well as the corresponding angles of rotation of both the pinion and the ring gear are recorded. Thus, the tooth contact path as well as the motion transmission error graph is determined. Then, the contact pattern that is formed by a set of instantaneous contact ellipses is designated.

The TCA results are essential for the assessment of the gear set quality in the early stages of the process of its development.

All the results presented in graphical form are very illustrative and easy to interpret.

This paper aims to present a comparison of numerical methods for determining the contact pattern of Gleason-type bevel gears. The mathematical model of tooth contact analysis and the finite element method were taken into consideration. Conclusions have been drawn regarding the usefulness of the considered methods and the compatibility of results. The object of the analysis was a bevel gear characterised by an 18:43 gear ratio and arc tooth line, and manufactured according to the spiral generated modified-roll method.

The mathematical model of tooth contact analysis consists of both the mathematical model of tooth generating and the mathematical model of operating gear set. The first model is used to generate tooth flanks of the pinion and the ring gear in the form of grids of points. Then, such tooth surfaces are used for the tooth contact analysis performed with the other model. It corresponds to the no-load gear meshing condition. The finite element method model was built on the basis of the same tooth flanks obtained with the former model. The commercial finite element method software Abaqus was used to perform two instances of the contact analysis: a very light load, corresponding to the former no-load condition, and the operating load condition. The results obtained using the two models, in the form of the contact pattern for no-load condition, were compared. The effect of heavy load on contact pattern position, shape and size was shown and discussed.

The mathematical models correctly reproduce the shape, position and size of the contact pattern; thus, they can be reliably used to assess the quality of the bevel gear at the early stage of its design.

Determination of the correct geometry of the flank surfaces of the gear and pinion teeth through the observation of contact pattern is a fundamental step in designing of a new aircraft bevel gear.

A possibility of the independent use of the mathematical analysis of the contact pattern has been shown, which, thanks to the compatibility of the results, does not have to be verified experimentally.

The purpose of this paper is to minimize the volume of straight bevel gear and to develop resistance towards scoring failure in the straight bevel gear. Two evolutionary and more advance optimization techniques were used for performing optimization of straight bevel gears, which will also save computational time and will be less computationally expensive compared to a previously used optimization for design optimization of straight bevel gear.

The following two different cases are considered for the study: the first mathematical model similar to that used earlier and without any modification to show efficiency of the optimization algorithm for straight bevel gear design optimization and the second mathematical model consist of constraints on scoring and contact ratio along with other generally used design constraints. Real coded genetic algorithm (RCGA) and accelerated particle swarm optimization (APSO) are used to optimize the straight bevel gear design. The effectiveness of the algorithms used has been validated by comparing the obtained results with previously published results.

It has been found that APSO and RCGA outperform other algorithms for straight bevel gear design. Optimized design values have reduced the scoring effect significantly. The values of the contact ratio obtained further enhances the meshing operation of the bevel gear drive by making it smoother and quieter.

Low volume is one of the essential requirements of gearing applications. Scoring is a critical gear failure aspect that leads to the broken tooth in both high speed and low-speed applications of gears. The occurrence of scoring is hard to detect early and analyse. Scoring failure and contact ratio have been introduced as design constraints in the mathematical model. So, the mathematical model demonstrated in this paper minimizes the volume of the straight bevel gear drive, which has been very less attempted in previous studies, with scoring and contact ratio as some of the important design constraints, which the objective function has been subjected to. Also, two advanced and evolutionary optimization algorithms have been used to implement the mathematical model to reduce the computational time required to attain the optimal solution.

This paper aims to propose a numerical method to calculate the convective heat transfer coefficient of spiral bevel gears under the condition of splash lubrication and to reveal the lubrication and temperature characteristics between the gears and the oil-air two-phase flow.

Based on computational fluid dynamics, the multiple reference frames (MRF) method was used to simulate the rotational characteristics of gears and the motions of their surrounding fluid. The lubrication and temperature characteristics of gears were studied by combining the MRF method with the volume of the fluid multiphase flow model.

The convective heat transfer coefficient can be improved by increasing the rotational speed and the oil immersion depth. Moreover, the temperature of the tooth surface having a large convective heat transfer coefficient is also found to be low. A large convection heat transfer coefficient could lead to a good cooling effect.

This method can be used to obtain the convective heat transfer coefficient values at different meshing positions, different radii and different tooth surface positions. It also can provide research methods for improving the cooling effect of gears under the condition of splash lubrication.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0233/

The purpose of this article is to present a method for the analysis of the quality of the bevel gear at the development level.

A non-commercial aircraft bevel gear design support system was developed. The system utilises matrix and vector calculi to model the technological machining systems and to analyse the contact of the designed pair. Both the technological model and the design model offer the possibility of manipulating the calculated parameters. This enables independent selection of the pinion/gear engagement, making it possible to achieved the desired contact pattern (its shape, position and size) and/or minimise motion transmission deviation. This article presents an analysis of the meshing of the aircraft transmission designed in two variants.

The newly developed non-commercial transmission design support system offers the capability to freely adjust mesh quality indicators. The first step is to perform automated technological calculations for a specific geometry of gear members, on the basis of which gear and pinion flanks are developed. Then, numerical models of tooth flanks are configured in the designed pair, and tooth mesh quality is verified. Quality indicators are provided in the form of summary contact pattern and the motion graph. In the subsequent step, changes are made to basic geometry of pinion tooth flank. After satisfactory mesh indicators have been reached, the transmission is tested for assembly errors and additional corrections are made to the geometry of the pinion tooth surface, as required. The above methodology guarantees that the assumed quality indicators are achieved on the physically cut transmission.

Fast preparation of the technology with guaranteed high mesh quality is a significant factor in the competitiveness of an industrial plant which implements a new bevel gear in its manufacturing activities.

The visualisation of the results of the use of the application allows the user to easily interpret the analysed contact pattern and take appropriate decisions as to the necessity of making corrections.

The finite element method (FEM) has become the prevalent technique used for analyzing physical phenomena in the field of structural, solid and fluid mechanics. The output of scientific papers is fast growing and professionals are no longer able to be fully up‐to‐date with all the relevant information. The purpose of this paper is to provide a bibliographical review on the application of FEM in mechanical engineering, specifically for the analyses and simulations of gears and gear drives from the theoretical as well as practical points of view.

The following topics on gears and gear drives are handled from the computational points of view: gears in general, spur gears, helical gears, spiral bevel and hypoid gears, worm gears and other gear types and gear drives. The paper is organized into two parts. In the first one each topic is handled in a short text, relevant keywords are presented and current trends in applications of finite element techniques are briefly mentioned. The second part lists references of papers published for the period 1997‐2006.

This bibliography is intended to serve the needs of engineers and researchers as a comprehensive source of published papers on design, analysis and simulation of gears and gear drives.

The bibliography listed is by no means complete but it gives a comprehensive representation of different finite element applications on the subjects. It will save time for readers looking for information dealing with described subjects, not having an access to large databases or willingness to spend time with uncertain information retrieval.

EXTREME PRESSURE OR EXTREME TEMPERATURE LUBRICANTS have been developed for two main fields—the lubrication of hypoid gears and as lubricants in metal working and it is of some interest to see how this development has occurred. Musgrave, in a most comprehensive paper on the Development and Lubrication of the Automotive Hypoid Gearf defined a hypoid as “a special form of spiral bevel gear in which the pinion axis is offset from the axis of the ring gear” and he pointed out that such gears had the advantages of quietness in operation, particularly at high speeds, greater tooth strength capacity, greater dependability and were more economic to produce as well as allowing lower body designs than spiral bevel or worm gears.

AT THE INTERNATIONAL CONFERENCE ON GEARING arranged by the Institution of Mechanical Engineers in London from the 23rd to 25th September, a special session was set aside for the Discussion of Lubrication and the following papers were presented :—