Special Gear Research Articles

Reverse design of involute helical gear pairs considering machining errors based on IMAGEWARE and HYPERMESH

Gears inevitably contain errors during the manufacturing and installation process, which can increase the vibration and noise of the gear system. The finite element model with error can accurately solve the variation of vibration and noise and meshing characteristics of such gear systems. This paper develops a combined analytical and simulation method for involute helical gears when machining errors are included. First, the tooth profile accurate point clouds of the involute gear are derived by cutting the tooth blank with the rack and the coordinate transformation function. Subsequently, the gear is reconstructed by the IMAGEWARE and UG. With HYPERMESH's powerful node editing capabilities, sinusoidal profile errors can be assigned to gears. Also, the intersection of the error gear with the tooth blank is used to find the apex, which has an essential effect on noise. Finally, the difference in static transmission errors of gears with and without errors is analyzed by ABAQUS. The results show that gears containing errors increase the peak-to-peak values of transmission errors, i.e., increasing noise. The method proposed in this paper can provide a basis for modeling and analysis of meshing characteristics of special gears that cannot be directly parameterized or gears with various errors.

Silent Threat Below: A Comprehensive Analysis of Manhole Gases and Health Effects

Manhole gases, often hidden underground in cities, can be really harmful to our health. This review looks at all the important aspects of these gases. It starts by talking about the different types of manhole gases, where they come from, and how common they are in cities. Then, it explains how people can be exposed to these gases, either by breathing them in or through their skin, with real-life examples to help understand better. Next, it talks about how these gases can make people sick, both in the short term with symptoms like dizziness and in the long term, leading to problems like lung diseases or issues with the brain. It also mentions that some people, like kids and older folks, are more at risk. To protect people from these dangers, the review suggests a few important ideas. It says we need to make sure workers and anyone near manholes are safe by following strict rules and using special gear. We also need to come up with new technologies and ideas to find and stop these gases from being a problem. Everyone must know about these risks, so there should be campaigns to tell people how to stay safe. In short, this review tells us that manhole gases are a serious concern for our health in cities. But by using smart strategies and keeping an eye out for these dangers, we can make sure everyone stays safe.

Parameter based definition of eccentric cycloid gearings

Current challenges for today’s industry are an increase in gear ratio in one stage, an increase in load capacity as well as an increase in efficiency compared to standard gears. The standard tooth profile for cylindrical gears is an involute. This tooth profile has certain limits for external gearings regarding its geometry, e.g., undercutting and a small radius of curvature near the base circle. Special gearings overcome these limits and offer an enormous potential in gear design through their adapted profile geometries. New manufacturing possibilities for gears, such as additive manufacturing or 5‑axis milling, mean that special gears can also be produced economically.In comparison to involute gears the description of non-involute gears is often not standardized and parameters describing the geometry are not commonly defined. Thus, it is not possible to adequately determine the corresponding properties. One of these special tooth profiles is the eccentric cycloid gearing (EC gearing), in which a circular profile rolls with a profile of a trochoid equidistant. This flank geometry can provide advantages over the standard involute in certain applications.This study introduces a geometric description of the EC gearing, which is based on a defined set of parameters. Besides the geometrical parameters, parameters describing the characteristics of the gearing are proposed in accordance with the description of involute gears. This parametric description of the EC gearing enables an analytical determination of the flank, the contact geometry and load-free characteristics. With the parametric description shown and the variation of the geometry possible with it, gearings suitable for practical applications can be generated.

ОСОБЕННОСТИ СТАБИЛИЗАЦИИ КОЛЬЦЕВЫХ ЗАГОТОВОК

Ring blanks are in demand in various branches of mechanical engineering in the production of large-sized bearings, turbine disks, special gears and other critical products. Besides high requirements to the ring blanks in terms of geometric dimensional accuracy, material structure and mechanical properties, in some cases the most important requirement is their production with absence of residual stresses and high stability of geometric shape. Specific features of ring rolling may lead to the occurrence of residual stresses, the magnitude of which is impossible to determine by the known methods of defect control. The paper analyzes the causes of shape error and residual stresses in the production of ring blanks in the process of ring rolling and heat treatment. The article also assesses the possibility of using different methods of shape stabilization and reduction of residual stresses in the manufacture of ring blanks for critical engineering products: expandable, thermal, thermomechanical, vibratory and ultrasonic treatment. For ring blanks designed for manufacturing critical parts, it is suggested to use shape stabilization and residual stresses reduction by means of cyclic loading after ring rolling and thermal treatment. The design scheme and force parameters of a device for stabilizing ring blanks on the basis of a double-acting lever-hinge mechanism are determined. The ring-rolling complex created at the Belarusian Automobile Plant will have potential opportunities to produce ring blanks for manufacturing of critical products in transport machine-building, aviation, space, defense and chemical industries of the Russian Federation. The results of the analysis of the methods for shape stabilization and reduction of residual stresses of ring blanks are planned to be used in the creation of this complex.

A Review on Hill Climbing Optimization Methodology

The activity of walking through hilly country for pleasure. He is an avid athlete and loves mountain walking. Mountaineering is a terrifying quest used for mathematical optimization problems in the field of artificial intelligence. Given a large input and a good horistic function, it tries to find a good enough solution to the problem. The mountaineering algorithm consists of three parts, where the global maximum or optimal solution cannot be reached: the local maximum, the ridge and the plateau. The trek is not complete or optimal, the time complex of O (∞) but the space complex of O (b). There is no special processing data system as mountaineering rejects old nodes. Trekking in the Alps or other high mountains. This is not an efficient method. This does not apply to problems where the value of the horticultural function suddenly decreases while the solution is in view. First-choice trekking enables balanced trekking by randomly creating heirs until something better than the current situation develops. Whenever this is a good strategy there are many (e.g., thousands) heirs in a state. So the first preferred mountain climbing is a special type Random mountain climbing. Description. This is a robust mountaineering algorithm. A person is initiated approximately. When the individual reaches a local optimal state a new solution is created approximately and mountaineering begins again. The best first search is a traversal technique, which checks which node is the most reliable and decides which node to visit next by checking it. To this end, it uses the appraisal function to determine travel. Climbing is used to describe traditional ‘siege’ techniques, where you will climb the mountain several times before being driven to the summit. Albinism, on the other hand, focuses on 'fast and light' climbs. Free climbing was created to describe any style of climbing that is not AIDS related. ... In free climbing, the climber moves the wall under their own force without the use of any special gear (except for the climbing shoes) to help them move upwards. Climbers can only survive for a short time in the 'death zone' at 8000 m and above, where there are numerous challenges. Deep cracks, avalanches, cliffs and snowflakes make the high form of trekking a very dangerous endeavor. Caldwell and George's son use headlamps to illuminate their way, climbing at night when the temperature is cold - meaning their hands sweat less and there is more friction between their rubber shoes and granite. According to the author, climbing mountains is a very difficult task for people and they enjoy crossing obstacles. Mountaineering is neither complete nor optimal, the time complex of O (∞) but the space complex of O (b). There is no special processing data system as mountaineering rejects old nodes

The influence of the angles of the asymmetrical gear rack on the geometrical and functional parameters for the pinion and gear with asymmetric teeth

The paper presents some research on the design of the asymmetric gears, special gears with involute asymmetrical teeth. The aim of these researches is to establish the influence of the angles of the asymmetrical gear rack upon some geometrical and functional parameters of the gears. We have used, as design method, the direct gear design, followed by the gear rack design, considering that asymmetric gears are not conventional gears, so the design method it is not the standard one. The results that are presented was obtained by using a computer modelling program, for asymmetric gears, in MatLab, and for one can see the asymmetric gears and the zone of the tooth action, a computer program in AutoLISP is developed. Based on the computer applications developed for determinate the geometrical parameters and for representing the teeth and gears models, the asymmetric teeth pinion and gear can be manufactured. Between the design parameters established at starting the described process there are the angles of the asymmetrical gear rack.

Development of the Technology for Manufacturing and Introducing a New Class of Tools with CVD Diamond for Grinding High-Precision Gear Wheels of Special Gear Units

Development of the Technology for Manufacturing and Introducing a New Class of Tools with CVD Diamond for Grinding High-Precision Gear Wheels of Special Gear Units

Розробка технології виготовлення та впровадження нового класу інструменту з CVD-алмазу для шліфування високоточних зубчастих коліс спеціальних редукторів

Розробка технології виготовлення та впровадження нового класу інструменту з CVD-алмазу для шліфування високоточних зубчастих коліс спеціальних редукторів

Nutritional evaluation of elongate mudskipper Pseudapocryptes elongatus (Cuvier, 1816) from Diamond Harbor, West Bengal, India

The mudskipper Pseudapocryptes elongatus (Cuvier, 1816), (Gobiidae) are caught throughout the year and they are considered as most edible mudskipper species in Sundarbans. They are targeted by special gears and sold live in large quantities in the local markets of Diamond Harbor, Namkhana and Kakdweep. The adult P. elongatus (14–18 cm total length) specimens were purchased from the Diamond Harbor landing center for evaluation of its biochemical components such as Protein, carbohydrate, lipid, amino acid, fatty acid, vitamin, and minerals. The percentage composition of protein was high (27.34%) followed by the carbohydrate (4.57%) and lipid (2.72%). The amino acids both essential (47.72%) and non-essential (42.91%) was found adequate. Among fatty acids, polyunsaturated fatty acid (PUFA) was found the maximum (31.55%) followed by saturated fatty acid (SFA; 27.66%) and monounsaturated fatty acid (MUFA; 19.55%). Vitamin A (112.5 IU/100 g) and Ca2+ (62.2 mg/100 g) were found maximum levels. The present finding supports that P. elongatus is valuable for human consumption due to its high-quality protein with well-balanced amino acids.

Mathematical approach to evaluate involute gear profile and helix deviations without using special gear software

The paper presents mathematical-geometrical approach to evaluate profile and helix deviations of cylindrical involute gear tooth flank without the usage of any specialised gear measurement software. The input data for the evaluation is represented by a set of Cartesian coordinates of surface points (points of contact between the measuring stylus and the measured surface) measured along the profile and flank curves by CAD based tactile gear measurement on coordinate measuring machine. This approach is based on deep study of ISO standards dealing with gear geometry, gear measurement and gear characteristics evaluation. Here, the development of general mathematical model of both helical and spur involute gear tooth flank surfaces is described and geometrical properties of these surfaces (important for corresponding CAD model generation) are mentioned. For practical application, mathematical formulas for calculation of profile and helix deviations from a set of measured points are derived. Due to the purely mathematical approach, no special gear measurement software is necessary for evaluation of profile and helix deviations. The required characteristics of involute gears can be evaluated by means of any general-purpose spreadsheet software. The presented method can be used not only in case of regular involute gear profile and helix inspection but mainly in case of those gear measurement standards that could not be measured as regular gears by commercial software because of unusual shape and design of the standards.

Dynamic Characteristics and Load Sharing of Herringbone Wind Power Gearbox

In this study, the dynamic model for the herringbone planetary gear transmission system is established by the lumped parameter method based on the system dynamics and the Lagrange equation, and the impact of the support stiffness and the torsional stiffness on dynamic characteristics is studied. The research results have a guiding significance for the design of the herringbone gear transmission system. In this model, the herringbone gear is treated as a special gear coupled by 2 opposite helical gears, where the stagger angle, comprehensive meshing error, support stiffness, support damping, and load inertia are considered in the analysis of dynamics. Moreover, the dynamic characteristic of the carrier is considered as well. By calculating the meshing force curve of the transmission system, the impact of the stagger angle, supporting stiffness, and the torsional stiffness on meshing force and load sharing coefficient is analyzed. The results show that the stagger angle has an obvious impact on load sharing coefficient while it has little impact on maximum meshing force. And the support stiffness has a more obvious impact on the dynamic characteristics of the system. The recommendary support stiffness of the system is that all of the support stiffness of the sun gear, planetary gear, ring gear, and carrier is 107 N/m. The torsional stiffness has little impact on the dynamic characteristics of transmission system, except the torsional stiffness of planetary gear, and carrier has an obvious impact on load sharing coefficient. The commercial software ADAMS carried out dynamics analysis of the transmission system to verify the necessity validity of the theoretical analysis.

Epidemiological Surveillance of Viral Hemorrhagic Fevers With Emphasis on Clinical Virology.

This article will outline surveillance approaches for viral hemorrhagic fevers. Specific methods for surveillance of clinical samples will be emphasized. Separate articles will describe methods for surveillance of rodent-borne viruses (roboviruses) and arthropod-borne viruses (arboviruses). Since the appearance of hantaviruses and arenaviruses in the Americas, more than 30 different species in each group have been established, and therefore they have become the most frequently emerging viruses. Flaviviruses such as yellow fever and dengue viruses, although easier to recognize, are also more widely spread and therefore considered a very important public health issue, particularly for under-developed countries. On the other hand, marburgviruses and ebolaviruses, previously thought to be restricted to the African continent, have recently been shown to be more global. For many of these agents virus isolation has been a challenging task: trapping the specific vectors (mosquitoes and ticks), and reservoirs (rodents and bats), or obtaining the samples from suspected clinical human cases demands special protective gear, uncommon devices (respirators), special facilities (BSL-3 and 4), and particular skills to recognize the slow and inapparent cytopathic effects in cell culture. Alternatively, serological and molecular approaches have been very helpful in discovering and describing newly emerging viruses in many areas where the previous resources are unavailable. Unfortunately, in many cases, detailed studies have been performed only after outbreaks occur, and then active surveillance is needed to prevent viral dissemination in human populations.

Investigation on the flank surface durability of gears with increased pressure angle

Within a funded research project (reference number 0325244C, BMWi – Federal Ministry for Economic Affairs and Energy of Germany), the load-carrying capacity of alternative involute gears was investigated. To find qualified variations for use in gear drives, increased pressure angles (αn > 20°) and/or asymmetric tooth shapes (αn 20°) have been examined experimentally. Optimization goals were the power to weight ratio of the transmission and the power density in the drive train. In this report gears with reference tooth shape (αn = 20°) as well as gears with modified tooth shape (αn = 28°) are discussed with focus on the load carrying capacity of the tooth flank with special regard to the damage mechanisms pitting, micro-pitting and scuffing. The results of experimental and test accompanying studies are shown. They allow a direct comparison between standard and special gears as well as a classification in context of the actual state of knowledge.

Geometry and contact characteristics of torus involute gears

Aimed at overcoming high sensitivity to machining or mounting error of line-contact conjugate surfaces, a novel torus involute gear drive is proposed which can compensate large axial misalignments and possess good meshing characteristics without lead correction. The torus involute gear is essentially a special spur gear with continuous shifting in the second order. Based on the processing principle of the torus involute gears, their mathematical models are established according to the corresponding imaginary rack cutter. In order to provide the approach to choose proper designing parameters, geometry characteristics of the torus involute gear are investigated: condition equations of tooth undercutting for a convex torus involute gear and tooth pointing for a concave torus involute gear are formulated utilizing the developed mathematical models, and the approach to checking tooth flank interference is provided. Contact characteristics of the gear set is studied through tooth contact analysis and finite element analysis. The simulated results produce useful information about tooth contact pattern, stress distribution, and transmission errors of the gear set.

Elite and ethical: The defensive distinctions of middle-class bicycling in Bangalore, India

This article applies social practice theory to study the emergence of sustainable consumption practices like bicycling among the new middle classes of Bangalore, India. I argue that expansions of bicycling practices are dependent on the construction of defensive distinctions, which I define as distinctions that draw equally on lifestyle-based and ethics-based discourses to normalize bicycling among Bangalore’s middle classes. With their environmental discourses and signage, middle-class cyclists make claims to being ethical actors and ecological citizens concerned about global environments. Their high-end bicycles and special gear enable them to maintain their social status in personal and professional circles, despite adopting what is an essentialized and stigmatized mobility practice in a social context where personal automobiles are a dominant symbol of respectability and propertied citizenship. These defensive distinctions are anchored in communities that facilitate social learning, skill-building, and the creation of collective identities. I highlight the importance of considering the role of ethical discourses in consolidating “low-status” social practices among “high-status” class fractions and discuss the implications of promoting sustainable consumption through the othering of the poor. By applying a social practice analytic to study middle-class bicycling practices, this article makes a significant contribution to the growing literature that investigates the applicability of practice-based approaches to environmental behaviors and sustainable consumption in a novel context.

Special Transmission Gear Invalidation Analysis Coupled with Finite Element Method Based on Meshless Local Petrov-Galerkin Method

Special Transmission Gear Invalidation Analysis Coupled with Finite Element Method Based on Meshless Local Petrov-Galerkin Method

A Simulation of the Dynamic Properties Impact Based on the Variable Pressure Angle of Ovoid Gear

This paper discussed some properties of ovoid gear. The gear is a kind of special gear that transformed from the non-circular gear, hence just like the non-circular gear it also has some unique properties itself. In the paper we did some research start from the transmission of non-circular gear and point out the variable working pressure angle property. Then toke the ovoid gear as an example to deduce the working pressure angle expression, and discusse the force between two separate tooth during the meshing process. After all those things has been done, a 3D model of ovoid gear was established under the help of Pro/E, and then imported it to the Adams to do some meshing simulation in order to find the contact force under the impact of variable working pressure angle.

Disk Form Grinding Wheel 3D Parametric Modeling of Quadruple-Arc Gear Based on OpenGL

Arc-gear tooth profile is complex, especially quadruple-arc gear, it cant be grinding by generating method, form grinding method is still has some difficult in wheel dressing. In this article, the author use software VC++6.0 and OpenGL developed a new and special gear software, when the tooth number and modulus of arc-gear to be machined and grinding wheel diameter is given, this software can generate disk form grinding wheel 3D model,this software is useful to arc-gear form grinding wheel dressing.

Analysis of Electric Field of Pulse Electrochemical Finishing of Shaped Cathode on Gears

Gear’s pulse electrochemical finishing (PECF) technology by shaped electrodes based on the numeral control technology, which controls gear dividing device and feed movement, is put forwards. Based on numerical simulation, electrochemical reaction region is dispersed. According to gear tooth profile and negative electrode surface equations, boundary conditions are inferred. The numerical simulation of the electric potential distribution in the calculation region has been shown. Under the optimized parameters, a mirror-like surface of gear teeth could be gained by PECF. The results show PECF can fulfill the advantages in the finishing some special gears with hard teeth.

Unstable Distal Radius Fractures: Restoration of the Radial Length with Use of Special Palmar Fixed-angle Plate

To describe the radiological and clinical outcome of unstable distal radius fractures treated with use of a palmar locking plate designed especially to restore the length of the radius. 19 patients (6 men and 13 women) with an average age of 55 (23-71) years with an unilateral unstable distal radius fracture were treated with open reduction and internal fixation with use of an special palmar locking plate. In the distal long hole of this plate a longitudinal gear drive mechanism is integrated, in which a digital knob device consisting of a handle with a serrated ring is inserted. By turning the handle the distal fragments which are fixed to the plate by locking screws are pushed distally with respect to the shaft fragment until the correct length of the radius is restored. The patients were followed for 12 months. During last follow-up, standard radiography, functional results and pain scores were assessed. All fractures united uneventfully with no secondary displacement, and no superficial or deep infection. Ulna variance measured on average - 0.8±1.5 mm. Wrist extension averaged 63°, wrist flexion averaged 59°. Grip strength averaged 82% of the contralateral uninjured side. The used special gear drive plate allows accurate restoration of the length of the radius even in unstable fractures with good clinical results.