Gearbox

An All-Terrain Vehicle is an Off Road vehicle that has the ability to drive on any terrain
without any difficulty. These vehicles are designed to sustain any sort of extreme loads that act
during off road driving. All-Terrain Vehicles are fitted with large tires with grooves for better
traction on slippery terrains, high ground clearance to avoid obstacles, and usually designed with
high torque rather than speed. As compared to commercial vehicles, these vehicles are designed
to be more strong and durable. These vehicles are vastly used in Deserts, Mountains, forests or any
other gravel surfaces.
All-Terrain Vehicles are vastly used in farming in India. Best examples are tractors and
snow mobiles. The main key for such vehicles is the powertrain assembly which is unique and
differs from other vehicles. The power train includes Engine, Manual Gearbox, Limited slip
Differential or in some cases a reduction gearbox coupled with a continuously Variable
Transmission (CVT).CVT is the new technology being implemented in Off Road Racing.
BAJA vehicles are the most famous Off Road Vehicles in India.However,due to the
extreme loads caused by the gravel tracks and the constraints to reduce the weight, one major
component is susceptible to failure—Reduction Gearbox. Gearbox is a costly component and on
failure, the vehicle is immobile The Power Train assembly is so complicated that it occupies a lot
of space in the vehicle hence increasing the overall weight. The aim of this project is to design a
gearbox that is compact, lightweight and has extended life. Major fields covered are Material
selection, Machine Engineering Design of Gears, Shafts, Gearbox Casing, Bearing selection,
Vibrations caused due to the Engine. These analytical designs have been validated through the
help of CAD and FEA software like SolidWorks and ANSYS. Various Analysis like Structural,
Repeated loads and Computational Fluid Dynamics (CFD) have been performed to study the
behavior of components and oil flow during operations. The design is also finalized with the fits
required for assembly and the final product is expected to be efficient, light weight, compact and
long lasting than the other Gearboxes being used today.
Keywords: All-Terrain Vehicle, Reduction Gearbox, Computer Aided Engineering (CAD),
Computational Fluid Dynamics (CFD), Vibrations, Finite Element Analysis (FEA)

Abstract- Before make gearbox we have to verify how it will work, performance, efficiency, which factors effecting gearbox performance. Which parameters like temperature and noise. we have to find out it’s effect on gearbox design before making gearbox by using modeling and/or various methods, then optimize that parameters which effects temperature and noise before making gearbox, we can also optimize our cost factor to make gearbox, And predict design for good gearbox. Hi-tech drives Pvt. Ltd. is manufacturer of Gear and Gearboxes. In Gearboxes when they are tested at that time noise and temperature limits to be taken care. Here our attempt is to apply DOE techniques to achieve desired design of gearbox for control the temperature and noise levels in gearbox.

Gear-shifting mechanism has a key role in transmission system of a vehicle. During gear shifting, there is a risk of losing the engine optimal speed that will ultimately lead to more emission from the vehicle. It is demanded for optimal performance of transmission systems to increase quality of synchronizer used for gear shifting. Especially in the case of heavy vehicles, the synchronizer performance needs to be robust more even during different operating scenarios. Synchronization process varies by changing its parameters values. So one of the ways to improve performance of the synchronizer is to optimizing its parameters. In the paper, a generic synchronizer mechanism (GSM) is considered. Mathematical model of GSM is presented based on constrained Lagrangian formalism (CLF) and detailed kinematics of synchronization
process in transmission system. Speed difference at the end of the main synchronization phase and synchronization time are chosen as two objectives. The following eight parameters of the synchronizer have taken as input parameters: cone angle, cone coefficient of friction, cone radius, rate of shift force, blocker angle, blocker coefficient of friction, gear moment of inertia, and ring moment of inertia. Influence of the parameters on objectives is studied. The values of the objective functions decrease with increasing some of the parameters and increase with increasing others. Not only the objective functions have opposite behavior between the parameters but also have opposite behavior with variation of the same parameters. For example, the synchronization
time decreases but the speed difference increases with increasing cone coefficient of friction. The Matlab routine of multi-objective optimization is applied to obtain the optimized parameter values of the generic synchronizer at different operating conditions. In the first case, the sleeve is considered as a master, in the second case the gear is considered as master, and in the third case both sleeve and gear are considered as slaves. In each case, three different operating conditions are studied which are nominal, transmission vibrations, and road grade. The obtained results of biobjective optimization (Pareto fronts, Pareto sets, and corresponding performance diagrams) are analyzed and the most influencing synchronizer parameters have been identified.

Design FMEA is structured method of identifying
potential failure modes and providing corrective actions
before first production run occurs. This paper aims to provide
probable causes of failure, levels of effects of failure and
corrective actions to be taken in the design phase for BevelPlanetary
Vertical Roller Mill Gearbox.

Wear of contact surfaces is one of the most common causes of gear failure. In addition to physical and chemical processes that occur in the contact zone, ki-nematic meshing parameters have a great effect on the wear process. This paper analyses the influence of geometric and kinematic parameters of the gear profile on the instantaneous friction coefficient of the trochoidal gearing in the gerоtor pump. The friction coefficient is not a constant value and it varies during the teeth meshing as a result of a constant change in the lubrication regime. There are many empirical expressions for calculation of the instantaneous friction coefficient, but due to numerous limitations, many of these expressions can be applied only to certain operating conditions and loads. The analysis of the friction coefficient was performed through two contact periods defined by the change in direction of the rolling velocity of the meshing profiles contact point. The obtained results enable identification of dominant factors that influence the instantaneous friction coefficient and show possibilities for further development of analytical models of mechanical losses in the gerоtor pump. There is a wide range of pumps used in modern industrial practice. One of the simplest is a gerоtor pump. Gerоtor (trochoidal) pumps are rotary pumps with in

Cycloid drives are a relatively new group of planetary power transmissions. These transmissions have numerous favorable characteristics, such as a wide range of transmission ratios, very compact design, high reliability in dynamic exploitation conditions, high efficiency, etc. As they are part of a newer generation of transmissions , the possibility of using other materials other than steel in their production is not yet fully investigated. For the purposes of this investigation a single stage cycloid reducer was designed and manufactured out of mainly plastic components. The theoretical efficiency was determined and experimentally tested. Their comparative analysis is given through the discussion. The paper concludes with suggestions for further research on this type of cycloid reducers.

In this paper are presented the power losses and sources of their occurrence in worm gear boxes. These are the losses that occur in the coupling of worm teeth and worm gear, losses in bearings, seals and oil churning power losses in the transmission. When the operation of worm gearing is characterized by line contact of coupled elements which is accompanied by significant sliding, the highest value have the power losses in the worm and worm gear coupling compared to other losses in gearing. Among other things, in the paper also presents the expressions that are used for calculation of individual power losses and efficiency of the gearing. The size of the losses primarily depends on the type of coupled material and geometry of worm pair, circumferential velocity (input rotational speed), the type and viscosity of lubricating oil, load, worm shape, and temperature and so on. The paper also deals with the influence of different factors on power losses and efficiency. As the efficiency of the worm pair is significantly lower compared to other types of gear pairs, the appropriate combination of geometric parameters and materials of worm and worm gear, lubrication and working conditions can significantly affect its increase.

Due  to  increased  competition  among  Indian  commercial  vehicles,  suppliers  there  is constant  challenge  to  bring  quick  and  innovative  solution  to  the  market.  Focus  is  on reducing  the  test  time,  rework  time  and  increased  use  of  CAE  analysis  which  is  now critical and important step in product development process.
Mechanical gear shifting system is one of the vital component used in gear system of a commercial vehicle. The system faces following critical constraints
a) Packaging Space (Constrained due to engine, NVH and other aggregates)
b) Ergonomics, gear selection and shifting forces and the  input  force reaching to the gear box for gear engaging and disengaging.
Since existing  method  of  designing  gear  shifting  system  has  short comings  as  pipe bending  has  always  been  problem  for  manufacturers  due  to  spring  back  in  material  of pipe.  This  leads  to  unwanted  efforts  to  optimize  the  systems  through  trial  and error methods.  Eventually  this
leads  to  loss  of  time  and  money.  For  years,  suppliers  have heavily relied  on  key  life  laboratory  testing  as  compared  to  providing  ground testing  to validate their design in product development process.
The core competence of the project is to focus on the methodology to optimize the existing  design of mechanical gear shifting system on heavy commercial vehicle by carrying out CAE  package  study using  DMU Kinematic tool. The  results  of  CAE have  taken  as reference to fabricate the prototype and to fit on actual vehicle and the test are conducted to make ready to fit solution.

A common feature of all engines with internal combustion is the need for a gearbox. This constructive requirement is justified with the practical fact that, if the torque and power characteristics of an engine would be geared directly to the working bodies of a consumer machine (such as road wheels) it could not ensure enough torque throughout the vehicles operational speed range. According to the operational task that the vehicle should manage, several solutions are used. Automatic (planetary) gearboxes and CVTs (Continuously Variable Transmission) allow gear ratio changes without power interruption. In other cases such as race car technology, multiple ratio gearboxes are caused by rules and regulations. In order to optimise gearbox performance, a wide range of analytical methods are used. One of the most frequently used, is the traditional straight line plot of road speed against engine rpm (rounds per minute) as a method of choosing ratios. Unlike this method, tractive effort curves include much more information and so they can publish how well ratios are suited to the engine`s characteristics as well as the fundamental track parameters that driven their choice. This paper should state out the benefits of tractive effort curves in gearbox analyse. In order to maintain this, an instance from the Formula 1 was taken. Based on onboard video records of different tracks (in this example the tracks in Monaco and Monza were chosen), authors could approximately determine points of gear change and top speeds achieved within a certain ratio. These information allow to set a group of tractive effort curves (as well as several road speed – engine rpm diagrams). A huge amount of data, related not just to the gearbox, can be obtain when comparing results of these two methods and using them together.

Most common planetary gear sets which
are implemented in numerous automatic
transmission systems are presented in this paper.
Automatic transmissions in which these gear sets are
implemented were also briefly mentioned. Alongside
these topics, cutting edge automatic transmission
systems alongside their schematics were also
presented. Current industry developments and future
of automatic transmission systems were also briefly
analyzed.

In this increasingly technological world, mining it’s the first step for any sketch and plays an important role in extraction and selective recovery to comply with the incessant demand of material that we need nowadays.

One of the most coveted materials it’s gold, necessary to wear as much for jewel like for
numerous application in the engineering world, since its use in aviation engines until applications of dentistry, among countless examples. But, how is supported this incessant hunger of gold?

This answer, some years ago, was to use a big quantity of workforce, which by means of hand tools they were able to get little amount of gold. Was a work tedious, not much remunerate and very dangerous.

In the middle of the XIX century, when they were discovered big rich zones in gold in Alaska and the northern zone of United States and Canada, they was knew like “gold rush” that’s did break up a little boom at the technological area beginning in this way a great number of surveys and digging of alluvial mining. Better machinery was available to be controlled by a small number of operators, obtaining large amounts of gold from the ground.

This inclination is continued until nowadays, that we have any type of high capacity mining machinery to obtain a high quantity of gold that’s present on the deck.

A type of machinery is known like “Trommel” o rotary screen, this machine is based on movement and pressure of water to release gold who it’s glued on the rock’s surface.

About this machine it is base the next project, we need a low spin speed, but enough for doing a progressive cleaning of rocks at the same time a high quantity of torque, for win all inertias and move with fluently rock- drum set.

So, for this, it is imperative to use a reducing mechanism able to harness the power of the engine and offer all requirements that we need, always taking into account security and protection of the environment.

Untuk melakukan perhitungan roda gigi, dibutuhkan data awal sebagai berikut : 1. Daya maksimum : 136 x 735,5 Watt = 100.028 Watt 2. Perbandingan rasio transmisi : a. Gear ratio 1 : 3,928 b. Gear ratio 2 : 2,142 c. Gear ratio 3 : 1,397 d. Gear ratio 4 : 1,000 e. Gear ratio 5 : 0,851 f. Gear reverse : 4,743 3. Sudut kemiringan gigi = 30 o 4. Sistem gigi yang digunakan = 20 o stub involute system 5. Material yang digunakan untuk pinion dan gear = Carbon steel 0,35% Carbon normalised dengan nilai Tensile Strength = 720 Mpa, nilai kekerasan = 229 BHN dan Modulus Young = 210.000 Mpa. 6. Safety Factor yang diambil = 4 untuk material carbon steel dengan pembebanan dinamis. 3.2. Perhitungan Awal 1. Tegangan statik ijin pinion dan gear σ i = σ SF = 720 MPa 4 =180 MPa 2. Surface Endurance Limit σ es =(2,8 BHN −70 ) MPa ¿ ((2,8 x 229)−70) MPa ¿ 571,2 MPa 45

Spectral analysis techniques to process vibration measurements have been widely studied to characterize the state of gearboxes. However, in practice, the modulated sidebands resulting from the local gear fault are often difficult to extract accurately from an ambiguous/blurred measured vibration spectrum due to the limited frequency resolution and small fluctuations in the operating speed of the machine that often occurs in an industrial environment. To address this issue, a new time-domain diagnostic algorithm is developed and presented herein for monitoring of gear faults, which shows

The most powerhl engine in the world is of little use unless the power from the engine can be safely and effectively transmitted to the ground. This, then, is the primary function of the transmission and driveline. In addition to being able to transmit the torque and power from the engine, the transmission and driveline also must allow the vehicle to operate over a wide range of speeds-from a standstill to the maximum speed of the vehicle. This implies that the system must inherently have some method of disconnecting the engine from the remainder of the driveline to allow the vehicle to remain stationary. Furthermore, the transmission also must be designed to satisfy the conflicting requirements of quick acceleration, high speed, and adequate fuel economy.

Bu makalede, özellikle otomotiv ve uçak sanayiinde kullanılan yüksek tork ve hız kapasitelerine sahip paralel eksenli dişli çarkların titreşim, gürültü, iletim hataları, aşınma, tork, hız ve sıcaklık gibi parametrelerini kontrollü olarak ölçmesi planlanan kapalı devre test düzeneğine ait dişli kutusunun tasarımı ve şaftın sonlu elemanlar programı ile analizi yapılmıştır. Dişli test kutusu iki adet paralel şaft ile bir birine bağlanmış düz veya helis dişliler, cıvatalar, pimler, volan, rulman ve gövdeden oluşmaktadır. Düzeneğe maksimum 500N/mm diş yükü ve 5000d/d hız uygulanmaktadır. Mekanik tasarım bu değerler üzerinden yapılmış olup geometrik tasarım için Catia programı, sonlu elemanlar analizi içinse MS Nastran (Sim Expert) programı kullanılmıştır.

Animal being a very useful resource in rural areas, an attempt has been made to develop a sustainable product which uses animal power as its input and can be utilized to support Indian agriculture. For this an animal driven prime mover, having a speed enhancement gearbox as one of its main components was studied by IIT Delhi in 2003. Here the improved design of that gearbox is provided which utilizes some advance design tools like MATLAB and Autodesk Inventor. For fast computation, all the design equations were programmed in MATLAB while the Autodesk Inventor provided quick visualization of the movement. Such tool allows one to systematically study such gearboxes to check their designs, e.g., whether they are over-designed or under-designed. In this paper, one such gear box made by Panchal Pumps Ltd., Kanpur, India was studied in detail and modifications were conveyed to the manufactures.

Equally spaced planetary gearboxes are important power-train components for varied engineering systems. Their failures can result in significant capital losses and pose safety concerns. The vibration measurements perceived by a sensor mounted on the gearbox housing can provide valuable diagnostic information without normal gearbox operation interference. However, such vibration based monitoring techniques are difficult to implement in planetary gearboxes because of the complex nature of measured vibration spectra that is a result of planets revolving with respect to the stationary sensors mounted on the gearbox housing. Previous research with simulations and experiments using such measurements has reported distinct sideband patterns in the resulting vibration spectra, which differ significantly from the spectra of a normal fixed-axis/parallel gear pair system. In this paper, Fourier series analysis is used to explain these distinct sideband patterns that contain rich diagnostic information. The results obtained are useful to understand the cause of the observed vibration behavior in both healthy and faulty planetary gearboxes and identify the locations of additional frequency components introduced by the damaged gear in a complex measured vibration spectrum. Thus, the formulation presented in this paper can assist in developing robust feature extraction algorithms for early detection of planetary gearbox failures. The theoretical derivations presented in this paper are validated by both dynamic simulations and experiments on a dynamometer test bed using a 750 kW gearbox damaged during its operation while installed in a wind turbine. The predicted frequencies for observed faults in the annulus and sun gears of the gearbox are vividly presented in the experimentally measured frequency spectrum.

Based on our previous work (Ma et al., 2014, Engineering Failure Analysis, 44, 179-194), this paper presents an improved analytical model (IAM) for the time-varying mesh stiffness (TVMS) calculation of cracked spur gears. In the improved analytical model, the calculation error of TVMS under double-tooth engagement due to repeatedly considering the stiffness of the filletfoundation is revised, and the effects of reduction of fillet-foundation stiffness of cracked gears and extended tooth contact (ETC) are also considered, which have a great influence on TVMS, especially under the condition of large torques and crack levels. Moreover, the comparisons among the IAM, traditional analytical model (TAM) and finite element (FE) model are also carried out under different torques and crack depths. IAM is also verified by comparing TVMS and vibration responses obtained by FE model, which can be considered as a gauge to evaluate the calculation error. The results show that the maximum error of IAM is about 12.04%, however, that of TAM can be up to 32.73%.

A tribo-dynamics model of a differential hypoid gear pair is presented, integrated with lubricated contact of meshing teeth pair with lubricants of varying rheological properties. Particular attention is paid to the effect of lubricant formulation and gear geometry on the system efficiency. The  influence of gear torsional dynamic response is taken into account in a 4-Degree of Freedom (DoF) model. The contact geometry and kinematics of the hypoid gear pair are estimated, using Tooth Contact Analysis (TCA). Two fully formulated gear lubricants of the same viscosity grade (SAE 75W-90) blended with the same additive pack, but with different types and concentration of viscosity modifier (VM) are considered. Conjunctional friction is predicted for viscous shear of fully characterised lubricants as well as boundary interaction of rough surfaces. The results show loss of friction resulting in resonant response of the gear pair with impact of meshing teeth exhibiting non-linear jump phenomenon. The predictions also show that lubricants with higher pressure – viscosity (PV) coefficients tend to exhibit increased power loss.

Dynamic characteristics of cracked gear systems, also known as cracked-gear rotor systems, have received increasing interests among industry and academy in the past two decades. This paper reviews published papers on the dynamics of cracked gear systems. These studies mainly focused on three topics: crack propagation prediction, time-varying mesh stiffness (TVMS) calculation and vibration response calculation; Study objects involve the spur gear, helical gear and planetary gear; Different modeling methods including analytical method, finite element (FE) method, combined analytical-FE approach were adopted. More specifically, this review is composed of three related parts according to the above three topics. The first part involves the prediction of the crack propagation path based on two-dimensional (2D) or three-dimensional (3D) gear models, which provides a basis for the hypothesis of crack path in the process of TVMS calculation of cracked gear pairs. The second part summarizes the TVMS calculation methods including analytical methods, FE methods, combined analytical-FE approaches and experimental methods. The final part reviews the dynamic models for vibration analysis of cracked gear systems including lumped mass models and FE models, where the crack effects are characterized by introducing TVMS of cracked gear pairs into the system dynamic models. The well known open problems about cracked gear dynamics are finally stated, and some new research interests are also pointed out. The review will provide valuable references for future studies on dynamics of cracked gears.

Improved fuel efficiency and reduced emissions are key drivers for modern drivetrain systems. Therefore, in recent years, dry sumps with air-oil mist lubrication have been used for efficient transmission design in order to reduce the churning losses. With dry sumps appropriate cooling measures should be implemented to dissipate the generated contact heat in an efficient manner. This paper integrates a tribological model with three dimensional thermofluid analysis in order to predict the heat generated in the lubricated meshing gear contacts and its dissipation rate by an impinging oil jet in air-oil mist environment. Such an approach has not hitherto been reported in literature. The results show that the generated heat under realistic conditions cannot be entirely dissipated by the impinging oil jet in the air-oil mist transmission casing. Numerical results are used to derive extrapolated regressed equations for heat transfer purposes for time-efficient analysis. These conform well with the detailed numerical results.

cycloidal speed reducers belong to the new generation of mechanical gears. cy cloidal speed reducers are increasingly used in modern engineering due to their good performances. Friction exists at all points of contact between the moving elements of cycloidal speed reducers, as one of the main causes of power losses in power transmission. In this paper, the friction of the contact of cycloid disc and housing rollers has been taken into account, while the friction at the contact of cycloid disc and output rollers, and at the contact of cycloid disc and central roller bearings are neglected. The effect of friction on the distribution of contact force, the friction torque value is analysed as well as efficiency. This paper pres ents 2 analytical models for calculating the values of contact force and friction torque. The 2nd model opposed to the 1st, taking into account the phenomenon of friction. The results showed that friction significantly affects the distribution of normal force. In...

In this study,Plates are used in  clutch systems ,adapte to marine transmisson systems and these plates  are tested according to safety factor for marine transmisson systems. Also hydraulic circuit is drawn. In coupling and clutch systems, Luk GmbH. and  AGN Stromag AG  are  leader companies in the world. Their free studies and researches documents contributed to this study.

Bu çalışmada, şanzıman sistemlerinde kullanılan lamelli kavramalar(plakalar) deniz şanzıman sistemlerine uyarlanarak, emniyet katsayısı hesabı yapılmış, güvenirliliği test edilmiş ve hidrolik devre  şeması çizilmiştir. Kaplin, kavrama sistemlerinde dünyada lider konumda olan Luk GmbH. ve GKN Stromag  AG firmalarının da dökümanları incelenerek bu çalışma ortaya konulmuştur.

Cycloidal speed reducers belong to the new generation of mechanical gears. Cycloidal
speed reducers are increasingly used in modern engineering due to their
good performances. Friction exists at all points of contact between the moving
elements of cycloidal speed reducers, as one of the main causes of power losses
in power transmission. In this paper, the friction of the contact of cycloid disc
and housing rollers has been taken into account, while the friction at the contact
of cycloid disc and output rollers, and at the contact of cycloid disc and central
roller bearings are neglected. The effect of friction on the distribution of contact
force, the friction torque value is analysed as well as efficiency. This paper presents
2 analytical models for calculating the values of contact force and friction
torque. The 2nd model opposed to the 1st, taking into account the phenomenon
of friction. The results showed that friction significantly affects the distribution
of normal force. Increase of the friction produces the contact forces and friction
torque increase, also, while efficiency is decreasing.

A real case study is represented of abrupt failures in a new multi-motor gear drive of vertical rolls in the heavy slabbing mill. Modal analysis is conducted, and the lowest torsional vibration modes are verified by the data from an industrial plant. Conditions of parametric resonances due to variable stiffness of teeth are determined within the range of working speed. The branched gear drive is investigated by the non-linear dynamical model with backlashes. It is shown that instantaneous dynamic loads in driveline are strongly dependent on the difference in gap sizes and phase shift between two intermediate gears in the output gear wheel coupling. Deviation in electrical parameters by 0.5 % is considered as the additional cause of not equal load sharing of parallel motors. Results of this research allowed preventing further failures of the gearbox and optimizing slabbing mill control. The proposed approach can be used in other multi-motor machines.

The gearbox of a wind turbine involves multiple rotating components, each having a potential to be affected by a fault. Detecting weak faults of these components with traditional demodulation analysis is challenging. Multi-scale enveloping spectrogram (MuSEnS) decomposes a vibration signal into different frequency bands while simultaneously generating the corresponding envelope spectra. In this study, a MuSEnS-based diagnosis approach is applied to detect faults affecting the intermediate stage of a gearbox installed in an operating wind turbine. The MuSEnSs of 12 vibration channels have allowed to identify multiple fault features, including the weak fault of the big gear on the sun shaft. The effectiveness of the proposed fault diagnosis approach has been tested with industrial data and the faults themself have been confirmed with the disassembled gears.

Wind turbines commonly undergo non-stationary flow and, not rarely, even rather extreme phenomena. In particular, rough terrains represent a challenging testing ground, because of the combination of terrain-driven flow and wakes. It is therefore crucial to assess the impact of dynamic loads on the turbines. In this work, tower and drive-train vibrations are analyzed, from a subcluster of four turbines of a wind farm sited in a very complex terrain. The main outcome of the study is that it is possible to start from the analysis of wind conditions and interpret how wakes manifest in the vibrations of the turbines, both at structural level (tower vibrations) and at the drive-train level. This wind to gear approach therefore allows to build a connection between a flow phenomenon and a mechanical phenomenon (vibrations) and can be precious to assess loads in different working conditions.

ASI memberikan zat-zat kekebalan yang belum dapat dibuat oleh bayi tersebut sehingga bayi yang minum ASI lebih jarang sakit terutama pada awal dari kehidupannya. Komponen zat anti infeksi yang banyak dalam ASI akan melindungi bayi dari berbagai macam infeksi, baik yang disebabkan oleh bakteri, virus dan antigen lainnya. Penyakit yang sering diderita oleh anakanak yaitu masalah pencernaan seperti diare atau gastroenteritis. Diare merupakan gejala yang terjadi karena kelainan yang melibatkan fungsi pencernaan, penyerapan dan sekresi. Diare disebabkan oleh transportasi air dan elektrolit yang abnormal dalam usus. Komplikasi yang dapat terjadi antara lain dehidrasi, gangguan sistem kardiovaskular akibat hipovolemia berat, kejang karena demam tinggi terutama pada infeksi Shigella, perforasi usus akibat demam tifoid, muntah dan kematian. Tujuan penulisan diharapkan mahasiswa mampu memberikan asuhan keperawatan pada anak yang mengalami diare. Metode penulisan adalah deskriptif atau gambaran suatu kasus dan kepustakaan. Hasil dari karya tulis ilmiah ini adalah mahasiswa memperoleh gambaran tentang asuhan keperawatan pada anak dengan diare. Masalah keperawatan berupa: Bersihan jalan nafas tidak efektif, Hipovolemia, Defisit nutrisi, Risiko infeksi, Gangguan pertumbuhan perkembangan.

This paper will review theoretical and practical techniques employed to analyze and reduce rattling noise in the gear
boxes. This paper involves solving the gear rattling noise problem at the very source to introduce a solution as a means to reduce
rattling noise. The gearbox noise problem solution is focused on the improvement of gear design; on the verification of its effect on
the radiated noise and the determination of the gears ‘contribution to the power transmission noise levels and on the analytical
and/or numerical computer-based tools needed to perform the analysis and diagnostics of gear rattling phenomenon. All of the
analytical methods are based on the time and frequency domain approach. Special care is addressed to the smoothness of the drive
resulting from the transmission error variation during a mesh cycle. This paper will review the progress in technique of the relative
teeth displacement; teeth contact force, eccentricity, backlash angle and its effect on gear noise due to the self excited vibration.
This presentation will include some examples of the use of such approaches in practical engineering problems.

Considering the effects of profile shift and tooth crack, Time-varying mesh stiffness (TVMS) is determined based on an analytical model and the result accuracy is also verified by Finite element (FE) model. Then, by introducing TVMS into the FE model of a gear rotor system, the combined effects of profile shifted gear pair under positive, negative and zero gear transmission conditions and tooth crack on the system vibration responses are analyzed. The time-domain waveform, frequency spectrum and instantaneous energy at a constant rotational speed are used to indicate the crack feature, and the amplitude frequency response is adopted to display the crackinduced response change. The results show that different modification conditions have great influences on the TVMS due to the change of contact ratio and tooth thickness. The sideband frequency and instantaneous energy both can be adopted to diagnose the tooth crack and evaluate crack levels, and the latter is more sensitive than the former. The amplitude frequency responses of profile shifted gear under small crack condition show slight change compared with those of normal gear, and the change of acceleration is more obvious than that of displacement.

This papers deals with the optimal selection of motors and reducers in servo-controlled machines. A model of an electromechanical servo-axis is developed, which allows electrical and mechanical losses to be evaluated. The model is based on data that can be extracted from commercial catalogs, thus requiring no experimental characterization. Then, a novel optimal selection procedure is presented, called continuous optimization, based on the extension of a discrete commercial catalog to a continuous one, by means of data fitting on the electromechanical parameters that influence the motor and reducer operation. A non-linear constrained optimization problem is solved in order to find the optimal motor-reducer unit with respect to a variety of objective functions, such as motor size, overall energetic efficiency, total mass, etc.

Considering the effects of extended tooth contact (ETC), revised fillet-foundation stiffness under double-tooth engagement region, nonlinear contact stiffness and tooth spalling defect, an analytical model for time-varying mesh stiffness (TVMS) calculation of spur gears is established. In addition, the analytical model is also verified by comparing the TVMS under different spalling widths, lengths and locations with that obtained from finite element method. The results show that gear mesh stiffness decreases sharply with the increase of spalling width, especially during the single-tooth engagement; the spalling length only has an effect on the beginning and ending of gear mesh stiffness reduction; the spalling location can affect the range of gear mesh stiffness reduction, and the range will reduce when the spalling location is close to the addendum. This study can provide a theoretical basis for spalling defect diagnosis.