Spiroid Gear Research Articles

Spatial motions transformers for incorporation into robot systems – review of the Bulgarian experience

This work is a review of research carried out by the author on the synthesis and design of the spatial gear mechanisms, oriented for incorporation in various technical devices, especially in robotic systems. It contains also a description of the innovative and inventive activities of the author over the years. The study illustrates the elaborated through the years, basic algorithms for the synthesis of spatial motions transformers (in particular Spiroid and Helicon gear sets), which are based on the mathematical model for synthesis upon a pitch contact point. The content of the solution of the two main tasks of the synthesis - synthesis of the pitch configurations and synthesis of the active tooth surfaces configures the mentioned above algorithm. Through it, real models of Spiroid and Helicon gear transmissions are synthesized and elaborated by 3D printing subsequently, which are designed for incorporation into robots of various purposes

Measurement Method of Temperature of the Face Gear Rim of a Spiroid Gear.

Spiroid gears are used to transfer heavy loads with a significant reduction in input speed. Like most toothed gears, they are lubricated with oil whose physical properties change with temperature fluctuations, affecting the durability and reliability of the gear. Bearing this in mind, gear designers plan systems for measuring oil temperature during gear operation at the design stage. The authors of this paper are of the opinion that, in the case of spiroid gears, it may be insufficient to measure only oil temperature during gear operation. It seems that the working temperature of a pair of mating wheels has a decisive impact on the durability and reliability of the gear. The measurement of oil temperature in a tested gear should be treated as a supplementary measurement with the measurement of temperature on the toothed wheels as the basic measurement. Taking into consideration the above, an innovative test bench was designed and built, making it possible to observe how working parameters of the gear (torque and rotational speed) affect the temperature of the lubricating oil, but most of all, the working temperature of the pair of mating wheels. This paper presents, among others, the results of research on the impact of the rotational speed of the input shaft and load on the distribution of temperature on the toothed rim of the face gear.

Vibration Diagnostics of Spiroid Gear

Abstract Spiroid gear is one of the progressive varieties of intersecting axis gears. It has a number of advantages: increased overlap coefficient, favourable contact conditions. Spiroid gears are notable for high loading and overloading ability, increased smooth running and less sensitivity to manufacturing and assembly errors, high reliability and durability. The analysis of the results of experiment on research of vibration of the spiroid gear PS-124 has shown, that the vibration level at frequency 200-300 Hz is reduced on 5 dB at increase of the resistance moment up to 1000 Nm at clockwise rotation of the reducer and at increase of the resistance moment up to 800 Nm at counterclockwise rotation of the reducer. The vibration level at frequency 700-800 Hz is also increased on 5 dB at increase of the resistance moment up to 1000 Nm at clockwise rotation of the reducer and at increase of the resistance moment up to 800 Nm. If these vibration levels are exceeded, a defect is likely to occur. Economic efficiency of application of diagnostics systems is caused by increase of reliability and quality, reduction of accidents, decrease in defects, reduction of idle time of expensive equipment, reduction of expenses for maintenance and repair.

Валидация модели упругопластического контакта спироидных передач

The paper considers the problem of analyzing the elastoplastic contact of teeth in a heavy-loaded low-speed multi-pair spiroid gear. This problem is an integral part of the strength analysis that enables forecasting the load-carrying capacity of the product at the initial stage of its development. The relevance of the considered method and algorithm of calculating the load distribution and plastic strain of teeth is emphasized by its increased productive efficiency as compared to the widely used finite element method. The paper considers a common issue of validation of the developed algorithm, i.e. the correspondence of the obtained solution to the results of a real loading process. The main steps of the algorithm are given with account of the multi-pair contact and macro-roughnesses on the contact flanks that are represented as the set of areas (cells). The coordinates of the cell centers are calculated taking account of the factors influencing the load distribution in the spiroid gearing, such as manufacturing and/or assembly errors, surface micro- and macro-roughnesses, and deformations of the gearbox parts. To validate the algorithm, only one dominating factor — the gearwheel surface undulation — is chosen, since all the other factors are negligibly small. The object of the study is a gear in one of the mass-produced multi-turn spiroid gearboxes for pipeline valves. The criteria for the algorithm validation are formulated, namely, the plastic strain value, the area, shape and arrangement of the pattern of the plastic strain. By analyzing the results of numerical and experimental modeling it is possible to draw a conclusion on the validity of the results obtained by means of the studied numerical method of analysis. The divergence of the plastic strain value obtained experimentally and through calculation was under 10%, and the area of the plastic strain pattern was under 10%.

Method of Calculating of Spiroid Gear Resource by Wear at Step Loading Mode

The brief analysis of reasons of failure of mechanisms and drives of lifting, construction, and road-building machines based on engagement drives, and worm-gear class drives, represented by contact destructions of active surfaces of cog-wheel cogs resulting in malfunctions, breakages, failures, such as wear and furrows, was carried out. The need to create a method for calculating the wear of spiroids with regard of variable loading mode and time was substantiated. The method developed allows, with regard of real modes of operation of handling machinery, equipment and machines, determine the wear intensity values and calculate the spiroid gear drive resource with regard of duration of action of diving torque values in accordance with the set variable loading schedule for lifting, construction, and road-building machines under the wear intensity of the spiroid wheel cog on values of driving torque on the spiroid gear drive output shaft, obtained from experiments.

Resource Assessment of Spiroid Gears Under Variable Loading Conditions

The brief analysis of reasons of failure of mechanisms and drives of lifting, construction, and road-building machines based on engagement drives, and worm-gear class drives, represented by contact destructions of active surfaces of cog-wheel cogs resulting in malfunctions, breakages, failures, such as wear and furrows, was carried out. The need to create a method for calculating the wear of spiroids with regard of variable loading mode and time was substantiated. The method developed allows, with regard of real modes of operation of handling machinery, equipment and machines, determine the wear intensity values and calculate the spiroid gear drive resource with regard of duration of action of diving torque values in accordance with the set variable loading schedule for lifting, construction, and road-building machines under the wear intensity of the spiroid wheel cog on values of driving torque on the spiroid gear drive output shaft, obtained from experiments.

Spatial meshing theory of involute spiroid gear drive with line contact

Spatial meshing theory of involute spiroid gear drive with line contact

Prospects of manufacturing spiroid gears with small gear ratios

Production of spiroid gears as alternatives to bevel and hypoid ones, when the gear ratio of the spiroid gear should be less than 10 (often less than 6) is traditionally related to problems of manufacturing multi-thread worms and hobs. Different versions of solving this problem in diversified series and mass production are considered. For the first case, improvements of traditional methods of analysis and the production technique are proposed basing on application of multi-thread hobs or multi-tooth assembled running-in cutting heads. For the second case, high production-efficient methods of gear machining of both gear elements are provided; they are implemented at simple and common lathes after their little modification. Features and restrictions of these methods are described. Numerical examples are given for the possible substitution of truck and tram hypoid gears by different versions of spiroid gears providing application of various methods of gearwheel tooth cutting while both keeping the same basic dimensions of parts and mounting dimensions and varying these dimensions. It is noted, that when choosing the parameters of spiroid gearing and machine-tool settings, there are methods of efficient control of operation and layout parameters of the gear, the level of contact localization and tool parameters.

Numerical simulation of elastoplastic contact of heavy-loaded spiroid gears

The paper presents the analysis of heavy-loaded low-speed multi-pair spiroid gears under the effect of elastic contact, bending and shearing, and elastoplastic contact interaction of spiroid gearwheel teeth and spiroid worm threads. The main stages of the developed algorithm for analysis of load distribution and plastic strain of flanks with account of elastic and elastoplastic contact conditions, multi-pair contact and macro-roughnesses on flanks are described in short. At elastoplastic contact the zones of plastic contact on flanks of spiroid gearwheel teeth are determined and the value of plastic strain is analyzed. The flanks of the spiroid gearwheel teeth and worm threads are represented in the algorithm as the set of segments (cells) with coordinates of centers determined with account of the analyzed factors that influence the load distribution in spiroid gearing. These factors are the errors of manufacturing and (or) assembly, micro-roughnesses, and deformations of spiroid gear supports. The paper gives the numerical results of research of the real spiroid gears of gearboxes for pipeline valves (PV) at elastic and elastoplastic contact represented as summary tables and diagrams of contact stress distribution along contact areas and of plastic strain, that show the workability of the algorithm. The presented numerical results of the algorithm functioning are well agreed with the experience of operation of spiroid gears and can be applied for analysis of load-carrying capacity of spiroid gears.

The development of gears technology used in rotary tables

The paper presents technology of forming of a face gear cooperating with cylindrical worm in spiroid gear drive application for rotation table. The method is based on application of a disc tool instead application of a hob. The solution is possible after application the CNC milling machine with five axis numeric system control. The method of forming face gear proposed in this article is based on application of the disc tool with a single blade edge and CNC milling machine. The method of forming the face gear cooperation with cylindrical worm on CNC milling machine with continuous divide and the scheme of the process kinematics have been presented in the paper.

The Effect of Materials on the Efficiency of the Spiroid Gearing

The contribution deals with is the material selection for spiroid gear. The combination of the softer material of one wheel with the harder material of the other wheel (or gear worm) is used for the trains of gears. The measurements were executed on the measurement stand comprising the machine aggregate with the spiroid drive. In Stage 1 of measurement, the spiroid gear was made of the steel gear worm and of the bronze wheel, in Stage 2 of measurements, it was made of the steel gear worm and of the plastic wheel. The efficiency was evaluated for various levels of the load moment, lubrication and material type used.

Development of Terminology in Gearing and Power Transmissions Part 2. Compilation of Reference-Dictionary Book on Gearing

В первой статье, опубликованной в журнале «Интеллектуальные системы в производстве»*, были рассмотрены этапы становления и развития терминологии по зубчатым передачам, в том числе в рамках деятельности Постоянной комиссии IFToMM «Стандартизация терминологии по ТММ». В данной статье рассматриваются вопросы подготовки материалов для составления словаря-справочника по зубчатым передачам и содержание основных разделов справочника. Показаны этапы развития идеи о создании издания справочного характера по терминологии зубчатых передач, начиная с доклада на Техническом комитете ISO TC (1998 г., г. Тун, Швейцария) до выхода в свет в 2011 г. пятого издания словаря-справочника [1]. Подготовка материалов для первого издания [2] была продолжена в 2000 году публикацией сообщения [3] о планируемом издании в сборнике докладов научного семинара 19-го рабочего заседания Постоянной комиссии IFToMM «Стандартизация терминологии по ТММ», в котором был проведен анализ состояния терминологии в области зубчатых передач. В сферу анализа были вовлечены стандарты: Международные ISO (4 источника), IEC (1); IFToMM (1), американские ANSI-AGMA (2), британские BS (2), немецкие DIN (4), швейцарские VSM (1), французские NF (5), российские ГОСТ (5) и болгарские BDS (2). По результатам анализа намечен план словаря и предполагаемый объем работы по привлечению и структурированию информационных материалов. Показана взаимосвязь подготовки материалов для словаря и главы 12 «Зубчатые передачи терминологии IFToMM» [4] , представлено содержание словаря в целом и отдельных его основных разделов. В частности, отмечена специфика разделов «Спироидные передачи» (введение терминов на немецком и французском языках); «Точность и контроль (компиляция терминов и обозначений из разных источников с дополнением терминами, идентифицированных авторами); «Расчеты на прочность и заедание» (выполненная авторами идентификация русскоязычной терминологии по расчетам на заедание с англо-, франко- и немецкоязычной терминологией); «Классификация зубчатых зацеплений, колес и передач» (дифференцированная по разным признакам - взаимному расположению осей, форме исходных поверхностей сопряженных звеньев и др.).

Method for Analysis of Elastically and Plastically Heavy-Loaded Low-Speed Spiroid Gear

Рассмотрена задача LTCA тяжелонагруженной низкоскоростной многопарной спироидной передачи с учетом влияния упругого контактного и изгибно-сдвигового и упругопластического контактного взаимодействия зубьев колеса и витков червяка. Задача LTCA упругопластически нагруженной передачи рассмотрена как комбинация двух задач: анализа - вычисление параметров нагруженного контакта; синтеза - поиска требуемой геометрии. Обоснован отказ от метода конечных элементов (МКЭ), обычно широко применяемого для решения задач LTCA. Приводится описание разработанного алгоритма расчета распределения нагрузки с учетом упругого и упругопластического характера многопарного контакта спироидной передачи, имеющей сложную пространственную геометрию. Предложена модель расчета величины пластической деформации в зависимости от первичной оценки перемещений в упругом контакте. Показано влияние погрешностей изготовления передачи на уровень нагруженности отдельных ее пар зуб - виток.

Calculation and Experimental Assessment of Self-Locking When Designing Spiroid Gears

Рассмотрены вопросы оценки свойства самоторможения спироидных передач. Выполнено геометрическое, математическое и физическое моделирование спироидного зацепления с целью оценки самоторможения. Описана последовательность оценки самоторможения спироидной передачи.

Design of double-crowned tooth geometry for spiroid gear produced by precision casting process

A novel double-crowned tooth geometry is proposed by the application of ease-off topography for spiroid gear manufactured by precision casting process, with the goals of localizing the bearing contact and obtaining a perfect function of transmission errors. The modified tooth surface is applied as the reference geometry to machine the die cavity geometry that will produce such geometry of the gears. The tooth geometry of crowned gear was achieved first from a pre-designed controllable function of transmission errors along the desired contact path. Then, the desired ease-off topography along the contact line is designed and calculated computationally from the given mathematic model of surface modification. The geometry of double-crowned spiroid gear could be reconstructed by superimposing the ease off of contact line direction on the profile-crowned tooth surface. The article provides numerical examples to validate the feasibility of ease-off modification methodology that was used to produce the double-crowned tooth geometry for the gears, while tooth contact analysis is performed computationally to investigate the stability of bearing contact and function of transmission errors to alignment.

One Approach to the Synthesis, Design and Manufacture of Hyperboloid Gear Sets With Face Mating Gears. Part 1: Basic Theoretical and Cad Experience

Abstract Hyperboloid gear drives with face mating gears are used to transform rotations between shafts with non-parallel and non-intersecting axes. A special case of these transmissions are Spiroid and Helicon gear drives. The classical gear drives of this type are the Archimedean ones. The objective of this study are hyperboloid gear drives with face meshing, when the pinion possesses threads of conic convolute, Archimedean and involute types, or the pinion has threads of cylindrical convolute, Archimedean and involute types. For simplicity, all three types transmis- sions with face mating gears and a conic pinion are titled Spiroid and all three types transmissions with face mating gears and a cylindrical pinion are titled Helicon. Principles of the mathematical modelling of tooth contact synthesis are discussed in this study. The presented research shows that the synthesis is realized by application of two mathematical models: pitch contact point and mesh region models. Two approaches for synthesis of the gear drives in accordance with Olivier’s principles are illustrated. The algorithms and computer programs for optimization synthesis and design of the studied hyperboloid gear drives are presented.

Comparative finite element method analysis of two spiroid worm gear drives having different profiles

With the knowledge of the advantageous characteristics of the cylindrical worm gear drives having arched profile in axial section and the conical worm gear drives having linear profile in axial section, a new geometric type conical worm gear drive has been designed and then manufactured, that is the conical worm gear drive having arched profile in axial section. Under same load and boundary conditions in case of the same geometric spiroid worm gear drives having arched profile and having linear profile in axial section we have done comparative finite element method analysis for evaluating the strains, deformations and stresses of this gear drives.

The kinematical model for the geometrically appropriate production of conical helicoidal surfaces having unvaried lead

During grinding of conical helicoidal surfaces that solution has to be chosen when beside the variable wheel profile that is caused by the wear of the grinding wheel, there is a possibility to keep the characteristics of the worm profile within the permissible tolerance level. By a new grinding technique, as a function of the shifting of the centre distance, the value of the wheel banking angle correction is constantly being varied along the pitch length of the worm. The mathematical calculation and the production technology are applied for a new geometrical, spiroid worm gear drive having arched profile in axial section (ellipse, circle, parabola, etc.) [2, 6, 7, 8, 9].

Kinematical Analysis of Gearboxes with Spiroid Gears

The paper investigates the issue of the asymetric worms´ profile (Fig. 10) of the spiroid gear comprising the direct line worm surface which occurs by the motion of the constituent direct line u upon the helix regarding the steady-state coordinate system 0 (x,y,z). There are described the characteristic attributes of spiroid gears in the article. Some kinematical inaccuracies caused by mistakes in gearing assembly are analyzed there. A testing stand is supposed to carry out an experimental research of inaccuracies influence on smooth run of machine aggregate.

Spiroid Gear with Composite Profile of the Worm – Hob Mill Tool

The spiroid gears are known and used due to their performances: increased gear ratio; reduced overall dimensions; the simplicity of the construction; increased carrying capacity on the gear flanks etc. The gears construction demand assurance of a certain geometry of the worm, which constitutes, in the same time, the basics for the generating tool of the spiroid wheel. In this paper, a worm with a composite profile is proposed. The profile is composed by an assembly of circles arc, in order to increase the length of the flank active zone. This design is intended to increase the contact length between the flanks of the spiroid worm and spiroid wheel, in order to decrease the contact pressure between the two parts and to improve the gear function process.