Gear Design

The chilled casting method is widely used in the metal casting industry to accelerate the mold's cooling rate. This method is very suitable for surface hardening by depositing the elements contained in the chill material onto the surface of the object being cast. One of the factors that influence surface hardness characteristics is the diffusion temperature. This study aims to determine the microhardness, surface layer thickness, and the element contained on the surface. The main material produced into Y-Block is ductile cast iron, the chill material is SS 304 plate with a thickness of 0.2mm. However, before the liquid material is poured into a mold, the chill plate is inserted into the surface of the pattern in the mold, then the plate was preheated. The result showed that the highest preheating temperature has produced microstructure around the surface area namely eutectic carbide of (FeCr)7C3, and (FeCr)3C. SEM-EDX analysis shows that 7.13%Cr is contained on the coating layer...

Semi-automatic Plant Pot Filling Machine is designed to make polythene pot filling in plant nurseries, faster and easier. A mix of soil is supplied to the machine and using a screw conveyor, the soil is transferred into the pot. Since there are many pot sizes, a mechanism has been implemented to change the speed of soil transferring.

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.

The chilled casting method is widely used in the metal casting industry to accelerate the mold's cooling rate. This method is very suitable for surface hardening by depositing the elements contained in the chill material onto the surface of the object being cast. One of the factors that influence surface hardness characteristics is the diffusion temperature. This study aims to determine the microhardness, surface layer thickness, and the element contained on the surface. The main material produced into Y-Block is ductile cast iron, the chill material is SS 304 plate with a thickness of 0.2mm. However, before the liquid material is poured into a mold, the chill plate is inserted into the surface of the pattern in the mold, then the plate was preheated. The result showed that the highest preheating temperature has produced microstructure around the surface area namely eutectic carbide of (FeCr)7C3, and (FeCr)3C. SEM-EDX analysis shows that 7.13%Cr is contained on the coating layer...

New version of Novikov helical gear combining double circular arc profile with crowned involute profile has been proposed in this paper. Generation of this gear is carried out using the required equations for these two profiles which are programmed using SOLIDWORK. To compare the resulting contact and bending stresses, three models of gear pairs are generated and investigated using finite element software package (ANSYS). The profiles of these models are as following: double circular arc for first model, crowned involute for second model, while the third model formed by combining double circular arc with involute crowned profiles. The results of stress analysis show that the generated stresses are lower in the proposed (combined) gear especially when the contact in the circular arc side. Keywords: Generation of gears, versions of Novikov Gears, circular arc gear, crowned involute gear, stress analysis in gears. 1. Introduction: Gears are mostly used to transmit power between shafts in several mechanical applications such that the rotary motion of the driven shaft is perfectly uniform relative to that of driving shaft [1]. In several mechanical applications gearing system is the preferred drive. As we know the toothed gearing has many advantages in compare with other mechanical drives such as its applicability for a wide range of torques and speed ratios, long service life and high reliability, can give constant speed ratio when there is no slipping as well as its small size [2]. These advantages illustrate the importance of developing gear profile. Today, three basic types of teeth profiles are used in gears for power transmission. They are involute, Noviko (or circular arc) and cyc1odial [3, 4]. One of the important causes of gear tooth failure is the presence of large contact and bending stresses in loaded gear tooth. These stresses lead to reduce the overall gear life and can result in tooth failure under loaded conditions [5]. A small reduction in the stresses leads to increase in the fatigue life of the gears considerable. Therefore it is important to find out the method of reducing induced stresses in the gear to increase gears life. Various improvements in gear design have taken place during the last few years such as use of material with improved strength, hardening the surfaces selectively with heat treatment and carburization, and improve the surface finish by shot peening. Many efforts such as using the asymmetric teeth, altering the pressure angle, introducing stress relief feature and using the gear with high contact ratio have been made to improve the strength of the gear [5]. Circular arc gears and crowned profile gears are superior compare with other types of gear profiles and they have higher load carrying capacity. In comparison with involute profile gear, crowned profile gear has a larger contact area, lower noise and vibration, and has a stronger tooth form [6]. Circular arc gears can take three to five times the load on the tooth flanks (in compare with involute gears) without detrimental pitting or wear, They more efficient in power transmission, and They retain lubricants between mating teeth more easily and form a thick oil film. Thus, the wearing of tooth flank is slower [7]. In this paper the asymmetric tooth profiles of two versions of Novikov gears will be used to reduce generated stress and increases gears life. These two profiles are double circular arc and crowned involute profiles. Double circular arc gear has higher bending and contact strength in compare with involute gear for the same parameters. This gear has been widely used in industry machinery [8].

This paper examines failure of helical gear in speed increasing gearbox used in the wind turbine generator (WTG). In addition, an attempt has been made to get suitable gear micro-geometry such as pressure angle and tip relief to minimize the gear failure in the wind turbines. As the gear trains in the wind turbine gearbox is prearranged with higher speed ratio and the gearboxes experience shock load due to atmospheric turbulence, gust wind speed, non-synchronization of pitching, frequent grid drops and failure of braking, the gear failure occurs either in the intermediate or high speed stage pinion. KISS soft gear calculation software was used to determine the gear specifications and analysis is carried out in ANSYS software version.11.0 for the existing and the proposed gear to evaluate the performance of bending stress tooth deflection and stiffness. The main objective of this research study is to propose suitable gear micro-geometry that is tip relief and pressure angle blend for increasing tooth strength of the helical gear used in the wind turbine for trouble free operation.

Thermal deformation and other factor, the bevel gear pair will appear serious phenomenon of meshing interference
and impact and uneven load in meshing process, so it is necessary to design suitable modification tooth to improve
gear pairs transmission performance and enhance its bearing capacity. A methodology, which facilities to analyze
the operating of bevel gears under consideration of production-caused deviations. The bevel gears are widely used
in aerospace, marine and other field.
Keywords:-Bevel gear, gear teeth, gear drive.

The Wildhaber-Novikov gear is one of the circular arc gears, which has the large contact area between the convex and concave profiled mating teeth. In (June 28, 1999), a new geometry of W-N gear with parabolic profile in normal section has been developed. This paper studies the generation of rack-cutters for parabolic crowned profiles with its generation in order to select the requirements of W-N gears.

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.

In this paper a new generation of asymmetric tooth profile gear is considered to enhance the dynamic behavior and vibroacoustic properties of toothed gear system. This paper presents a non linear dynamic model as a single degree of freedom equation for teeth meshing gear system which includes static and dynamic transmission error in order to investigate the influence of time varying mesh stiffness and periodic tooth errors on dynamic load factor for symmetric and asymmetric spur teeth profile. A new model of nonlinear time varying mesh stiffness is based on four types of deflections with consideration a small pressure angle for loaded tooth profile side and high pressure angle for another side. The complicated variation of meshing stiffness as a function of contact point along the mesh cycle is studied. Typical dynamic load factor equations are developed for symmetric and asymmetric tooth gear in single and double tooth contact by studied symmetrictooth with pressure angle (20 0 /20 0) and two pairs of asymmetric teeth (14.5 0 /25 0 & 20 0 /25 0). The effect of pressure of asymmetry and static transmitted load on transmission error and dynamic load factorare studied. The results indicate enhancement percentage in transmission error and dynamic load factor for asymmetric teeth profile compare with that symmetric tooth profile. 1. Introduction For the combination of high speeds and heavy loads encountered in modern engineering applications of the toothed gear, a precise analysis of the gear dynamic behavior is imperative. A New generation of asymmetric teeth gear play important role to increase load capacity, endurance ,long life and reduction vibration and noise. Transmission error (Tm) which is mean the difference between theoretical and actual angular position of driven gear when driver gear operating at constant speed ,therefore transmission error represent major excitation source for vibration and noise in geared system ,and reduction in transmission error represent major aim for researchers many decades ago, moreover gear vibration and noise level arise due to other several reasons [1] such as the error in the gear teeth profile at the contact point , misalignment between shaft axes , impact between mating teeth ,backlash, sliding and rolling friction between mating surface of gears ,bearing and housing ….etc. Most efforts to reduce the vibration and noise generation at the mesh have been directed towards improving the accuracy of manufacture. But, experience proves that the improving of manufacturing accuracy does not reduce the vibration and noise level considerably [2]. Several studies in literature have been conducted on the design and stress analysis of asymmetric tooth gear, little of them transact this approach dynamically, kaplelevich[3] present analytical method to design a gear with asymmetric tooth side surface, he consider a high pressure angle for the drive side and low pressure angle for the coast side teeth , Yang [4] provide geometrical modeling to design the asymmetric helical gear meshing when assembly errors are present, he constructed Stress analysis for the helical and the cylindrical form ,Mallesh et al. [5,6] generate asymmetric spur gear tooth geometry for different pressure angles on drive and coast side using computer programme to create a finite element model of gear tooth and investigate the effect of bending stress at the critical section for different pressure angles, different number of teeth and module , Ekwaro-Osire et al. [7] employ the inverse problem technique for asymmetric gear teeth which include photo elastic experimental work , Wang et al.[8] extend the edge – based smoothed point interpolation method (ES-IPM) in the bending strength analysis of asymmetric gear with various drive pressure angles side which generated by a special rack cutter , Agrawal et al. [9] Had been tested an asymmetric gear virtually with ANSYS code under a predefined loading and it has been investigated how bending stress changes at the fillet region of the asymmetric gear .Karpat et al. [10] present dynamic analysis of spur gear with symmetric and asymmetric teeth gear ,they consider high pressure angle for the drive side and low pressure angle profile for the coast side teeth ,they develop a MATLAB-based virtual tool to analyze dynamic behavior of spur gears with asymmetric teeth. In This work a new mathematical model for nonlinear mesh stiffness and dynamic load factor formula are developed for symmetric & asymmetric teeth meshing gear system then investigate the influence of asymmetry on dynamic load factor and transmission error .

The chilled casting method is widely used in the metal casting industry to accelerate the mold's cooling rate. This method is very suitable for surface hardening by depositing the elements contained in the chill material onto the surface of the object being cast. One of the factors that influence surface hardness characteristics is the diffusion temperature. This study aims to determine the microhardness, surface layer thickness, and the element contained on the surface. The main material produced into Y-Block is ductile cast iron, the chill material is SS 304 plate with a thickness of 0.2mm. However, before the liquid material is poured into a mold, the chill plate is inserted into the surface of the pattern in the mold, then the plate was preheated. The result showed that the highest preheating temperature has produced microstructure around the surface area namely eutectic carbide of (FeCr)7C3, and (FeCr)3C. SEM-EDX analysis shows that 7.13%Cr is contained on the coating layer...

The aim of this project to evaluate the contact stress of plastic material in gear for heavy duty loading condition. Plastic gears have good qualities like self-lubrication, low density, corrosion resistance and smooth running besides its lower strength. Plastic materials provide adequate strength with weight reduction and they are emerging as a better alternative for replacing metallic gears. In this work Poly Ether Ether Ketone (PEEK) material is used. These plastic materials have semi crystalline thermo plastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. An APDL gear model has been developed for the design evaluation and comparison study. Gear design parameter like module, face width and pitch circle radius etc can be varied to optimize the design parameter in the geared APDL model to make plastics as feasible gear model. The contact stress of plastic spur gears are calculated by Finite Element Analysis using FEA software ANSYS 13.0.Contact Stress of plastic gears was analysed in this project.

The principle objective of this paper is the comparison study of the static stresses for spur gear with different pressure angles. The analyzed results of a symmetric type involute profiled spur gear pair at different pressure angles are compared. Gears are one of the most important and crucial component in a mechanical power transmission unit and also in most of the industrial rotating machineries. Generally, a spur gear pair in action undergoes two types of stresses: the bending stress and the contact stress. In this paper, both these stresses on the gear tooth pair are analyzed using the finite element analysis and are compared. The stresses on the gear tooth are first analyzed using a finite element software and then those results are validated using the conventional formulae for finding stresses in gear tooth.

This paper studies the equations of rack cutters for generating involute gears with asymmetric teeth. The asymmetry means that different pressure angles are applied for driving and coast sides, respectively. By applying the equations of designed profile of rack cutter, the principle of coordinate transformation, the theory of differential geometry, and the theory of gearing, the mathematical models of involute helical gear is given. Trochoidal envelope traced by cutter is investigated. Computer graphs of asymmetric involute helical gears are presented based on the given model, and also generation simulation is illustrated.

The chilled casting method is widely used in the metal casting industry to accelerate the mold's cooling rate. This method is very suitable for surface hardening by depositing the elements contained in the chill material onto the surface of the object being cast. One of the factors that influence surface hardness characteristics is the diffusion temperature. This study aims to determine the microhardness, surface layer thickness, and the element contained on the surface. The main material produced into Y-Block is ductile cast iron, the chill material is SS 304 plate with a thickness of 0.2mm. However, before the liquid material is poured into a mold, the chill plate is inserted into the surface of the pattern in the mold, then the plate was preheated. The result showed that the highest preheating temperature has produced microstructure around the surface area namely eutectic carbide of (FeCr)7C3, and (FeCr)3C. SEM-EDX analysis shows that 7.13%Cr is contained on the coating layer...

The transient phenomena occurring during gear operation are investigated using a recently evolved gear model to simulate gear dynamic behavior and determine the circumstances under which they occur. Gear eigenfrequencies are calculated and correlated with gear physical properties and the effects of stiffness variation during a mesh cycle are studied. Time and frequency domain analysis is used to interpret the results of the computations.

The chilled casting method is widely used in the metal casting industry to accelerate the mold's cooling rate. This method is very suitable for surface hardening by depositing the elements contained in the chill material onto the surface of the object being cast. One of the factors that influence surface hardness characteristics is the diffusion temperature. This study aims to determine the microhardness, surface layer thickness, and the element contained on the surface. The main material produced into Y-Block is ductile cast iron, the chill material is SS 304 plate with a thickness of 0.2mm. However, before the liquid material is poured into a mold, the chill plate is inserted into the surface of the pattern in the mold, then the plate was preheated. The result showed that the highest preheating temperature has produced microstructure around the surface area namely eutectic carbide of (FeCr)7C3, and (FeCr)3C. SEM-EDX analysis shows that 7.13%Cr is contained on the coating layer at a thickness of 0.020 mm and an average hardness of 700-900 HV.

A gear-specific form is developed for the parametrical equations of tooth profile tangency to obtain a more versatile form for the equations of non-conjugate gear meshing. The new formulation allows the explicit solution of these equations to determine the path of contact and the resulting transmission error for modified tooth profiles during engagement progression. The transmission errors and the shape of the actual path of contact are calculated and the dynamic response of a gear pair is computed over a range of speeds.