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SPIRAL BEVEL GEAR DESIGN AND DEVELOPMENT -GENERATION AND SIMULATION OF MESHING AND TOOTH CONTACT ANALYSIS (TCA)
FOR IMPROVED PERFORMANCE –DISCUSSION & CONCLUSION
1ASHOK KUMAR GUPTA, 2DR.VANDANA SOMKUWAR
1Research Scholar (Ph D Mechanical Engineering), AISECT University,Dist: Raisen, Near Bhopal (M P)
2Professor, Mechanical Engineering Education Department, NITTTR, Bhopal (M P)
ABSTRACT:-Computer technology has touched all areas of today’s life, impacting how we obtain railway tickets, shop online and receive medical advice from remote location. Computer-based design analysis is nowadays a common activity in most development projects. When new software and manufacturing processes are introduced, traditional empirical knowledge is unavailable and considerable effort is required to find starting design concepts. This forces gear designers to go beyond the traditional standards- based design methods. The results obtained are in agreement with existing knowledge. The transformation has had a vast influence on gear manufacturing as well, providing process improvements that lead to higher gear quality and lower manufacturing costs. However, in the case of the gear industry, the critical process of Generation and Simulation of Meshing and Tooth Contact Analysis (TCA) of Spiral Bevel Gears remains relatively unchanged. Spiral bevel gears are crucial to power transmission systems, power generation machines and automobiles. However, the design and manufacturing of spiral bevel gears are quite difficult. Currently, the major parameters of spiral bevel gears are calculated, but the geometries of the gears are not fully defined.
The procedures needed to develop spiral bevel gear sets for a new product can require months of trial-and-error work and thousands of dollars. In view of increasing global competition for lower priced products, bevel gears are a prime target for the next generation of computerization. Answering this challenge, it has realized a new modified method through a shift in the way spiral bevel gear development is performed.
The Gleason face hobbing process has been widely applied by the gear industry. But so far, few papers have been found regarding exact modelling and simulation of the tooth surface generations and tooth contact analysis
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(TCA) of spiral bevel gear sets. The developed face hobbling generation model is directly related to a physical bevel gear generator. A generalized and enhanced TCA algorithm is proposed. The face hobbling process has two categories, non-generated (Format®) and generated methods, applied to the tooth surface generation of the gear. In both categories, the pinion is always finished with the generated method. The developed tooth surface generation model covers both categories with left-hand and right-hand members. Based upon the developed theory, an advanced tooth surface generation and TCA program is developed and integrated into Gleason CAGE™ for Windows Software. Most of the truck manufacturers have been confronted with ever more increasing demands on their products and on the development process. These demands are reflected in higher engine power, lower vehicle noise, higher fuel economy and shorter lead times in development. In most of commercial vehicle, single stage spiral bevel gears are used in the rear axles. In engineering, new product development (NPD) is the complete process of bringing a new product to market.
1. OVERVIEW
Computer-based design analysis is nowadays a common activity in most development projects. When new software and manufacturing processes are introduced, traditional empirical knowledge is unavailable and considerable effort is required to find starting design concepts. This forces gear designers to go beyond the traditional standards-based design methods. The results obtained are in agreement with existing knowledge. The transformation has had a vast influence on gear manufacturing as well, providing process improvements that lead to higher gear quality and lower manufacturing costs. However, in the case of the gear industry, the critical process of Generation and Simulation of Meshing and Tooth Contact Analysis (TCA) of Spiral Bevel Gears for Improved Performance remains relatively unchanged.
Gearing is one of the most critical components in a mechanical power transmission system, and in most industrial rotating machinery. A gear is a mechanical device often used in transmission systems that allows rotational force to be transferred to another gear or device. The gear teeth allow force
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to be fully transmitted without slippage and depending on their configuration, can transmit forces at different speeds, torques, and even in a different direction. Throughout the mechanical industry, many types of gears exist with each type of gear possessing specific benefits for its intended applications. Bevel gears are widely used because of their suitability towards transferring power between nonparallel shafts at any required angle or speed. Spiral bevel gears have curved and slope gear teeth in relation to the surface of the pitch cone. As a result, an oblique surface is formed during gear mesh which allows contact to begin at one end of the tooth (toe) and smoothly progress to the other end of the tooth (heel), as shown in Fig 1.4.
Fig 1 Spiral bevel gear mesh
Spiral bevel gears, in comparison to straight or zerol bevel gears, have additional overlapping tooth action which creates a smoother gear mesh.
This smooth transmission of power along the gear teeth helps to reduce noise and vibration that increases exponentially at higher speeds. Therefore, the ability of a spiral bevel gear to change the direction of the mechanical load, coupled with their ability to aid in noise and vibration reduction, make them a prime candidate for use in the automobile industry and others. The American Gear Manufacturing Association (AGMA) has developed standards for the design, analysis, and manufacture of bevel gears.
The driving and driven gears are the most important components of the Heel
Toe
Heel Toe
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Gear box of any automotive. Modelling allows the design engineer to let the characteristic parameters of a product drive the design of that product.
During the gear design, the main parameters that would describe the designed gear such as module, pressure angle, root radius, tooth thickness and number of teeth could be used as the parameters to define the gear.
Spiral bevel gears are used to transmit power between shafts that are typically at a 90-degree orientation to each other. The teeth on spiral bevel gears are curved and have one concave and one convex side. They also have a spiral angle. The spiral angle of a spiral bevel gear is defined as the angle between the tooth trace and an element of the pitch cone, similar to the helix angle found in helical gear teeth. In general, the spiral angle of a spiral bevel gear is defined as the mean spiral angle.
Because spiral bevel gears do not have the offset, they have less sliding between the teeth and are more efficient than spiral and produce less heat during operation. Also, one of the main advantages of spiral bevel gears is the relatively large amount of tooth surface that is in mesh during their rotation. For this reason, spiral bevel gears are an ideal option for high speed, high torque applications.
2. CONCLUSION
The robust and computerized tooth generation approach along with the tooth contact analysis provides a better way to reduce the wear, noise and vibration problems related to spiral bevel gears. Also, the optimization of tooth profile can be done with greater proceedings to the calculations.
Ultimately, we should think of automated soft-wares for designing that would create an optimized model of the gear tooth profile just by inputting the basic parameters. The conventional spiral bevel gears are continuously being investigated in order to reduce the failure or increase their transmissible power level, either by developing new composite materials or by modifying the gear tooth geometry. A mathematical model of an ideal spiral bevel and hypoid gear-tooth surfaces based on the Gleason hypoid gear generator mechanism is proposed. Using the proposed mathematical
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model, the tooth surface sensitivity matrix to the variations in machine–tool settings is investigated. Surface deviations of a real cut pinion and gear with respect to the theoretical tooth surfaces are also investigated. An optimization procedure for finding corrective machine–tool settings is then proposed to minimize surface deviations of real cut pinion and gear-tooth surfaces. The results reveal that surface deviations of real cut gear-tooth surfaces with respect to the ideal ones can be reduced to only a few microns.
Therefore, the proposed method for obtaining corrective machine–tool settings can improve the conventional development process and can also be applied to different manufacturing machines and methods for spiral bevel and hypoid gear generation.
In this chapter, an accurate and practical method based on ease-off topography was proposed to perform loaded and unloaded tooth contact analysis of spiral bevel and spiral gears having both types of local and global deviations. Manufacturing errors causing global errors and localized surface deviations were considered to update the theoretical ease- off to form a new ease-off surface that was used to perform a loaded tooth contact analysis. Two numerical examples of (i) face-milled spiral gear set with local deviations and (ii) face-hobbed spiral gear set with global deviations measured by CMM were presented to demonstrate the effectiveness of the proposed methodology as well as quantifying the effect of such deviations on load distribution and the unloaded and loaded motion transmission error.
The robust and computerized tooth generation approach along with the tooth contact analysis provides a better way to reduce the wear, noise and vibration problems related to spiral bevel gears.
Also, the optimization of tooth profile can be done with greater proceedings to the calculations. Ultimately, we should think of automated soft-wares for designing that would create an optimized model of the gear tooth profile just by inputting the basic parameters. The conventional spiral bevel gears are continuously being investigated in order to reduce the failure or increase their transmissible power level, either by developing new composite
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materials or by modifying the gear tooth geometry. A mathematical model of an ideal spiral bevel and spiral gear-tooth surfaces based on the Gleason spiral gear generator mechanism is proposed. Using the proposed mathematical model, the tooth surface sensitivity matrix to the variations in machine–tool settings is investigated. Surface deviations of a real cut pinion and gear with respect to the theoretical tooth surfaces are also investigated.
An optimization procedure for finding corrective machine–tool settings is then proposed to minimize surface deviations of real cut pinion and gear- tooth surfaces. The results reveal that surface deviations of real cut gear- tooth surfaces with respect to the ideal ones can be reduced to only a few microns. Therefore, the proposed method for obtaining corrective machine–
tool settings can improve the conventional development process and can also be applied to different manufacturing machines and methods for spiral bevel and spiral gear generation.
3. LIMITATIONS OF THE RESEARCH WORK
a. The confines of this research study are as follows;
b. Even though vibration analysis is not suitable for variable speed wind turbine generator where he loads and speeds are not stationary, the random vibration analysis was carried out to located the failure of bearing and it was not included in this doctoral work.
c. As the ice layers in the nordic climate, Inset collision in the warm humid climate, sand blast of blade and mix up of sand particles with the grease lubricant in desert like environment & liable to corrosion by the sea shore climate, the effect of ambient temperature on the performance of wind turbine components is not considered in the present work.
d. Even though time frequency analysis (or) ARMA models and motor current signature analysis are more apt for fault diagnosis in wind turbine gearboxes, because of the restriction to omplete the doctoral work within the stipulated time, the scholar has concentrated on that inspite of his own interest.
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