Papers by Keyword: Spur Gear

Abstract: Damage or failure frequently occurs on gearbox gears. If this occurs in the gearbox of tractors, this can be severe. This study aimed to determine the cause of the spur gear fracture through empirical and simulation studies. The hardness test was undertaken employing the Rockwell method where the fracture surface was observed using a scanning electron microscope (SEM) in order to identify crack initiation and the type of fracture. The stress intensity factor was next analysed using the finite element method (FEM). The results of the chemical composition testing indicated that the material used was according to the AISI 8620 standard containing an element of Carbon (C) of about 0.142 %.The hardness value of the gear was 109 HRB. The observation of the fracture surface showed a brittle fracture surface, suggesting that an impact load had occurred. The simulation results using the FEM also showed that the maximum stress intensity factor and K_I value occurred at the centre of the tooth. The value of K_I was shown to be larger than the fracture toughness and (K_IC). Therefore, this result indicates that a crack will continue to propagate until final failure.

Abstract: Spur gear is the most basic type of parallel-axis gear. In this study, contact stress and fatigue life of spur gear for different modules and for different materials were studied. The commercially available Solidworks 2016 is used for modelling and ANSYS Workbench tool for discretizing and solving. The analysis has been performed on the gear models of modules 1mm, 2mm and 3mm to observe the distribution of contact stress and life. The graphic results obtained were compared and it was found that contact stress decreases as the module increases and also aluminium alloy was having the least stress and high fatigue life among the selected materials. Hence from the finite element analysis, it’s found that the contact stress depends on the module and material used. Similarly fatigue life of gear purely depends on the material chosen.

Abstract: In the field of Engineering and Technology, Gear is one of the most significant and essential component in mechanical power transmission system. General devices have major applications in various fields like automotives, industrial rotational machines, lifting devices, etc. Gears are usually subjected to fluctuating loads while in action. Gear tooth mainly fails due to excessive bending stress and excessive contact stress. Thus while designing the gear it is very necessary and vital to analyze the stresses induced in the gear for its safe operation. Weight reduction of gear is also one of the main design criteria as it has a great role in improving the efficiency of the entire system. Nowadays engineering components made up of composite materials and plastics find increasing applications. The components made by the composite materials provide reasonable mechanical properties with minimum weight. The objective of this research is to develop the spur gear and pinion assembly model using engineering simulation PTC Creo and imported to 3-D design software ANSYS workbench 16.0 for working on the static structural analysis. The analysis was carried out by considering different materials for gears like structural steel, polycarbonate and 20%AlSiC. From the observed results it was found that, 20%AlSiC composite material has mass reduction of about 45%, hence it is suitable for light weight applications.

Abstract: Knowing the stresses and pressures in the contact between two deformable solids is fundamental in order to optimize the strength and the lifetime of mechanical components such as bearings or gears. These constraints can be determined by the calculation (finite element method or Hertz theory) or by experimental methods such as photoelasticity. The objective of this study is to model and compute the stress field and contact pressure using 3D finite element software. The validation of obtained results is done by comparison with the classical results of the non linear Hertz theory between two deformable cylinders. An application to spur gears with a circle involute profile is done and also validate with the same Hertz theory.

Abstract: Gear teeth are deformed due to the load. The tooth deformation of spur gears is not constant for all examined teeth of gears. Tooth deformation is depends on the shape of the teeth, on the basic parameters of examined spur gear, such as the number of teeth, module gearing, pressure angle, gearing width, correction and modification of gearing.

Abstract: The gears are some of the most used mechanical transmission due to the advantages its provide: constant transmission ratio, high power transmitted, high efficiency, small size, silent operation, precision kinematic, etc. This causes the wheel to be one of the most valuable machine elements both in terms of accuracy and processing technology as well. From the technological point of view due to high precision and productivity, one of the most methods used is processing with gear hob cutter. Although the tool profile does not depend on the number of teeth on the wheel, but only its module, large diversity of gear requires the design of gear hob cutters tailored to existing needs. As it is known the gear hob cutters are complicated and expensive gear cutting tools, both due to the manufacturing process and in terms of design, requiring a significant amount of calculations, high effort from the designer and consequently results in a large cycle of design. For this reason, the literature and in various websites, there are many studies and research information to optimize the design process and increase accuracy of gear hob cutters.

Abstract: Spur gear is used to transfer rotary motion between parallel shafts. The simplicity in its design is one of the advantages of the spur gear. However higher frictional force that is accumulated on the gear teeth will influence the spur gear performance. Many previous papers elaborated extensively on the contact stress in the spur gear but few of them gave the details on how friction affects the gear teeth. There are insufficient frictional effect data in the gear and thus should be regarded as an important research parameter. In this paper, the contact stress of spur gear has been evaluated with and without friction by employing the Hertz theory, AGMA standard and finite element method (FEM). The frictionless contact stress result has been validated with both the theoretical methods with minimum deviation. Frictional coefficient range of 0.0 to 0.3 was selected and the corresponding contact stress is directly proportional to the friction coefficient. The work also involves the variation of face width of the gear set under the influence of friction. The contact stress of spur gear was found to be inversely proportional to the face width.

Abstract: Gear tooth modification such as lead crowning can reduce stress concentration at the edges of the gear teeth; therefore prolong the fatigue life of gears. A logarithmical lead profile was applied on spur gears and the surface coordinate equation of logarithmic crowned tooth for manufacturing was established. On the basis of the contact mechanics model, the deformation equation of compatibility and load equilibrium equation were solved with an iterative numerical algorithm, and the corresponding programs were developed in Matlab to calculate the distributions of contact stress and von Mises stress field inside the subsurface layer at any meshing position. The numerical results of some typical examples show that the level of stress concentration before modification changes with the engaging locations of the gear teeth, and so does the amount of logarithmic modification along the line of contact, which can completely eliminate the edge effects of tooth surface at every meshing position during the spur gear transmission process, and thus improves the fatigue resistance of gear teeth surfaces.

Abstract: This paper proposes a system of nonlinear equations to manipulate the amplitude of parabolic function of transmission errors. Firstly, the characteristics of parabolic function of transmission errors are defined. Then, a system of nonlinear equations for manipulating the amplitude of parabolic function of transmission errors is created based on both the conditions of contact and the constraint on the amplitude of function of transmission errors. As the number of independent scalar equations in the system minus the number of unknown parameters is one, one extra design parameter can be applied to manipulate the amplitude of parabolic function of transmission errors. The solution to the extra design variable is automatically, precisely, and efficiently determined by the computer program which is created based on the Newton’s root finding method. The time-consuming manual iterations for trying the value of design variable are eliminated. The proposed method can be applied to both two-and three-dimensional gearing problems. At last, a pair of meshing gears composed of a circular-arc spur gear and an involute spur gear is presented to verify the methodology proposed in this paper.

Abstract: Gear teeth are deformed due to the load. Recently, at ever faster evolving computer technology and the available literature, we can encounter modern numerical methods, such as finite element method (FEM), which can serve as methods for the determination of deflection gearing. This paper deals with stiffness and deformation of teeth of spur gears solution by finite element method.