Siniša Kuzmanović

HCR Gearing and Optimization of its Geometry

A special kind of the basic involute profile of non-standard gearing is called high contact ratio (HCR) gearing, where the contact ratio is higher, there are always at least two pairs of teeth in contact and the unit addendum height is not equal to one like for standard gearing. Thus, the tooth height is increased. When HCR gearing is used, it is not necessary to achieve a greater gear load capacity, but nevertheless there is a greater risk of interference due to the greater tooth height. The advantages of HCR gearing is higher resistance (load is distributed on more pairs of teeth at the same time) and a lower relative noise level of gearing, which can be significantly reduced by using an integer HCR factor. HCR profiles are more complicated than standard involute profiles, they have a greater predisposition for interference, pointed tip thickness and undercut of teeth during production (primary production interference). Due to increased addendum height, there is a larger possibility of some interference or pointed tooth tip occurring. Therefore, these issues need to be prevented in the design phase, and ensured that all relevant equations and constraints are satisfied. The described method of finding optimal gear parameter values uses a Generalized Particle Swarm (GPS) optimization algorithm and MATLAB. The GPS optimization is shown to be a very fast and reliable method.

GENERALIZED PARTICLE SWARM ALGORITHM FOR HCR GEARING GEOMETRY OPTIMIZATION

Abstract Temperature scuffing evidenced by damage to teeth flanks of gears is one of the mostimportant problems needing to be solved in the process of gearing design and calculation. Accordingto current valid standards, such calculations can be resolved with a high level of reliability for all theusual gearing types. However, suitable calculations for HCR gears have not been adequatelyresearched to date. It has been identified that in HCR gears some different process of scuffingformation occurs during the gear‘s operation. In this article, the authors describe a new method forfinding optimal solutions for * a1 h , * a 2 h and x1, using a Generalized Particle Swarm OptimizationAlgorithm.

Optimization of HCR Gearing Geometry from a Scuffing Point of View

The paper deals with an issue of increasing the resistance of HCR external involute gearing from a scuffing point of view. It reports on a difference between involute gears with low contact ratio (LCR) and those with high contact ratio (HCR). The paper describes scuffing as the most significant damage done to the teeth flanks of HCR involute gears. In the case of warm scuffing, it is the combined action of high pressure between surfaces, high sliding speeds, and excessive contact temperature, resulting from pressure and sliding speed values, which consequently cause oil film rupture between the teeth flanks. Adopting a suitable geometry of the tooth curve profile, certain values of addendum heights for the meshing wheel will be defined according to the criteria of specific slips and corrected head shapes of the teeth of both wheels. The paper deals with the assessment and theoretical analysis of the impact of the HCR tooth profile resistance to scuffing on the basis of integral temperature criterion according to the Winter-Michaelis criterion. The basic relations for assessing the scuffing properties of an HCR involute gearing profile are derived, as well as the optimization of geometrical parameters of HCR gearing based on theoretical considerations on the properties of HCR gearing in terms of its resistance to warm scuffing combined with geometrical constraints against interferences. Finally, the results of the obtained optimization are compared with experimental results provided in previous research. A significant benefit in a theoretical area is the generalization of the integral temperature criterion for involute HCR gearing. By optimizing the criterion for the integral temperature of involute HCR gearing, the minimal flash temperature is obtained and the condition for the occurrence of scuffing is minimized.

Influence of the Teeth Number on the Gear Module Value and Load Capacity of Gear Pair in Universal Helical Gear Drives

The basic parameters of the universal gear drives, except the axis height, are not defined by the standard, so the manufacturers of universal gear reducers can define them in their way. Most of the manufacturers followed the parameter values of universal gear reducers of leading world producers in order to ensure their interchangeability and the better positioning of their gear units at the market. This paper deals with the analysis of the influence of the gear pair teeth number on the size of the module, as well as on the load carrying capacity of single-stage universal gear units. For defined gear ratio values, different combinations of teeth number of pinion and driven gear were selected. Further, it was made calculation of the basic geometric dimensions of the gear pair, as well as the load capacity. ARTICLE HISTORY Received 10.01.2018 Accepted 28.02.2018 Available 15.03.2018

Different Selection Procedures of Universal Worm Gear Drives

The purpose of this paper is to point out the usual methods of determining the service factor, which is the most influential parameter. In order to provide the proper selection of the size of the worm gear reducer, manufacturers are trying to take detailed look at all the factors which influence the work gear and to provide customers with the best possible solution. The greatest impact on their defining has a safety factor which is used to calculate the gear unit and the effect of an ambient temperature i.e. cooling method.

Research of HCR Gearing Properties from Warm Scuffing Damage Point of View

Abstract The issue of design and dimensioning of HCR gearing, particularly of the gearings with an internal engagement, it nowadays, especially in the design of hybrid cars drives, highly topical. This kind of gearing has many advantages in operation, but at the same time it is more complicated in stage of its design and load capacity calculation. Authors in this contribution present some results of temperature scuffing research of internal and external HCR gearing. There are given the equations for calculation of warm scuffing resistance of both external and internal HCR gearing derived according to the integral temperature criterion.

Evaluation and Choice of Conceptual Solutions for a Universal Geared Engine Reducer

This paper deals with the issues of evaluation and choice of conceptual solution for a universal motor gear reducer, usually carried out during its development. It is a known fact that reducers could be delivered with a motor installed or in the so-called motorless version. In case of the delivery version with the motor, they could be equipped either with special reducer electric motors or with standard (IEC) motors. In case of a reducer intended for the special motor, in motorless version it has to be equipped with IEC motor adapter, for the customer’s option to use standard motors, plus it should have a classic input shaft. In case of a reducer delivered with IEC motor, its motor might be connected indirectly, using IEC motor adaptor, or directly onto the reducer, without the use of adaptor. In both cases the reducer has to be delivered with a classic input shaft. This paper conducts the evaluation of some particular solutions by leading reducer manufacturers, with the intention to point out the most satisfactory conceptual solution.