CHAPTER-1 INTRODUCTION 1.1
Introduction Engineering in general, and Mechanical engineering in particular, deals
with a wide spectrum of products, ranging from large and complex systems comprising of numerous elements down to a single component. Apart from being a physical object, a product can also be a service that requires the application of engineering knowledge, skills and devices to be useful to society. A service falls under the category of a system in that it is carried out with the help of personnel, facilities and procedures. The service offered by an automobile maintenance and repair garage would be a typical example from mechanical engineering. Even computer software could be treated as an engineering product. It is also created using engineering knowledge and skills. In the following, the term product when used alone denotes the object to be designed and made with the help of engineering knowledge and skills, irrespective of whether it is a large system, a simple machine, a component or a service. Specific reference to design of computer software is not attempted in the following although many of the generalities apply to it also. A general understanding of the nature of product is a prerequisite for designing it. A complex product can be sub divided into sub assemblies or sub system, component etc. Frequently the planning, layout and design of a complex multi element product is an interdisciplinary effort, requiring the expertise and skills not only of several engineering specialization but even non engineering ones. It is always preferable that our work should be easy and fast. But easy and fast working requires some technical skills to work efficiency and properly. In our daily life we face many problems where we need a lot of effort and time 1
to do that specific work. A little but important work we do often is opening a tyre of a vehicle. It is a fact that a huge effort is required to open a single nut of a car wheel and it will become a tedious task to open the wheel in extreme atmospheric conditions. It also creates problem when we are in hurry. Here we get the solution of the problem mentioned above Multi nut remover is a special tool designed by us which will open a tyre easily. It is so designed that it can open all the four nuts of a car wheel in one time. And the most desired achievement we get is that total effort and time needed in the process is very less. It can open and also refit the tyre with the same tool easily. Tool is simple in design, easy to use and easily portable along with the vehicle. Overall of instrument is in the reach of average citizen. Great efforts are made to satisfy each and every technical aspects of the design. 1.2 List of Parts
SR. NO. 1 2 3 4 5 6
PART NAME GEARS(spur) PINION(spur) 19mm SPANNER BOX SHAFTS Base plate or Base Rod KEY
NUMBER 4 1 4 4 2 4
7.
L Shaped anchore bolts
5
8.
Cotter
4
1.3 Application Application domain of unified Wheel Opener is in automobile industries. According to our preplanned project we describe the following places where it can be used successfully: 2
It can be used as standard equipment provided with a new vehicle for the purpose of opening and refit a punctured wheel in the midway. It can be used in workshops to open a wheel in place of using pneumatic guns which are restricted to the availability of light and compressed air; it can be easily operated with hands. It can be used in assembly line of automobiles where more time is consumed in tightening all the four nuts one by one. As it takes less time to fit a new tyre, it will lead to increase productivity. 1.4 Objective A simple mechanism if used properly can lead to a great success. U.W.O. is a tool which is made for automobile field. Aim of our project is to save time and human effort. We have tried our best to adopt the design having minimum input torque and required output torque which is not possible without using U.W.O. 1.5 Organization at Work Completion of any work requires proper planning and management from the initial stage. From case study to fabrication different steps are involved. First of all we decide the aim of our project. Application of our design, benefits and other aspects are discussed in the first chapter. In the second lap of our work we finalize about the material required for the fabrication of different parts. A lot of engineering materials are studied before the selection of material. After the selection of material the big work is to design each and every part of the project. Design of gears, shafts, axles, sprockets, pinion and other parts are described in next pages.
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CHAPTER-2 LITERATURE REVIEW 2.1
Introduction
A lot of research activities has been carried out on gears mechanisms since very first gear was manufactured. A gear transmits the power from one shaft to another in various relative position. Many engineers and designers put there efforts in this field and succeeded also. They put all of their knowledge and the studies about gears on papers, with the use of these papers anyone can know about advancement of the research carried out by them. With these research papers, we come to know various aspects about gear. These papers explore how a mechanism can be driven at uniform speed and non– uniform speed. Also these papers tells about selection of material for a gear depending upon requirement. There are a number of different gears which have different application areas. The research papers helps in choosing the appropriate type of gear. Wen-Hsiang Hsie in his paper “An experimental study on cam-controlled planetary gear trains” describes that a mechanism is driven by a motor at uniform speed. However, more and more researches indicate that there are many advantages if a mechanism can be driven at non-uniform speed, and this kind of mechanism is called a variable input mechanism. The purpose of this work is to propose a novel approach for driving a variable speed mechanism by using a cam-controlled planetary gear train, and to investigate its feasibility by conducting prototype experiments. First, the geometrical design is performed. Then, the kinematic equations and the cam profile equations are derived based on the geometry of the mechanism. Cam-controlled planetary gear trains (CCPGT) are planetary gear trains with cam pairs. Chironis illustrated a CCPGT in his book From the exploded view .it is composed of a cam groove (the frame), a sun gear (the output), a planetary 5
gear, and an arm (the input). In general, the planetary arm rotates at constant speed, and drives the planetary gear to revolve around the sun gear and to spin around itself simultaneously. At the same time, the planetary gear produces an oscillatory motion through the contact of the attached roller and the cam groove. Therefore, the sun gear can produce a non-uniform motion by engaging with the planetary gear. The main advantage is that it can produce a wide range of nonuniform output motion. Kuen-BaoSheu in his paper “Analysis and evaluation of hybrid scooter transmission systems” describes a new design concept of transmissions for the hybrid scooters. These transmissions consist of a one-degree-of-freedom planetary gear train and a two-degree-of-freedom planetary gear train to from a split power system and to combine the power of two power sources, a gasoline engine and an electric motor. In order to maximize the performance and reduce emissions, the transmissions can provide a hybrid scooter to run five operating modes: electric motor mode; engine mode; engine/charging mode; power mode, and regenerative braking mode. The main advantages of the transmissions proposed in this paper include the use of only one electric motor/generator, need not use clutch/brake for the shift of the operating modes, and high efficiency. Motorcycles/scooters are providing the basic and personal transport services in many of Taiwan’s urban areas. This cause air pollution in Taiwan’s urban areas is rapidly increasing to dangerous levels since a major source of emission comes from the exhausts of gasoline scooters. Existing and proposed battery-powered scooters have low performance and therefore been sold only in small quantities and are not widely used. Hybrid vehicles are widely investigated recently. This is because, that from economical and technical points of view the hybrid concepts offer the possibility of achieving to fill the gap of zero emission powered and gasoline engine powered vehicles.
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Ligang Yao Jian S. Dai Guowu Wei and Yingjie Cai in their paper states that investigates meshing characteristics of the toroidal drive with different roller shapes, examines the effect on the characteristics from roller shapes and produces a comprehensive comparative study. Based on the coordinate transformation, the paper introduces the generic models of meshing characteristics and characterizes the meshing to introduce both undercutting and meshing limit curves. The paper further develops meshing functions and their derivatives with respect to each drive type with a different roller shape. This leads to a comprehensive examination of each meshing characteristics against each drive type of a roller shape. The comparative study focuses on the effect of contact curves, tooth profile, undercutting, meshing limit curves and the induced normal curvature. The toroidal drive offers the advantages such as a high horsepower-to-weight ratio, coaxial configurations, compactness, and high operating efficiencies. It combines most of the positive attributes of a circular worm-gear drive and an epicyclic gear drive without their negative aspects due to the introduction of rollers in meshing contact with rolling movement between a sun-worm and planet worm-gears, and between a stationary internal gear and planet wormgears. Using rollers as meshing media is popular in mechanical transmissions such as ball screws, roller gear cams, roller enveloping worm drives, cycloid drives, and the toroidal drives. Meshing via rollers which leads to rolling contact has the advantages of lower noise and higher transmission efficiency. It has a substantial effect on meshing characteristics. Comparative analysis of meshing characteristics with respect to different meshing rollers of the toroidal drive. Gordon R. Pennock and Jeremiah J. Alwerdt in their paper “Duality between the kinematics of gear trains and the statics of beam systems” describes about the geometric insight into the duality between the first-order 7
kinematics of gear trains and the statics of beam systems. The two devices have inherent geometrical relationships that will allow the angular velocities of the gears in a gear train to be investigated from a knowledge of the forces acting on the beams of the dual beam system, and vice versa. The primary contribution of the paper is the application of this duality to obtain the dual beam system for a given compound planetary gear train, and vice versa. The paper develops a systematic procedure to transform between the first-order kinematics of a gear train and the statics of the dual beam system. This procedure provides a simple and intuitive approach to study the speed ratios of a planetary gear train and the force ratios of the dual beam system. It is interesting to note that planetary gear trains (commonly referred to as epicyclic gear trains) were known, and in use, at least 2000 years ago. Despite the antiquity and widespread applications in machinery, however, the principles of operation of planetary gear trains are not generally understood. Also, the literature devoted to planetary gear trains is scarce at best although a comprehensive treatise on the theory of epicyclic gears and epicyclic changespeed gears was written by Levai. Planetary gear trains offer advantages over ordinary gear trains, for example, for the same speed ratio they can be smaller in size and have less weight. There are several techniques that are commonly applied to the kinematic analysis of planetary gear trains; for example, the instant center method, the principle of superposition using a tabular method, and identifying the fundamental circuits of the train. Also, an analogy between planetary gear trains and beam systems using one-dimensional vectors was presented by Kerr. The available methods, however, do not provide geometrical insight into the gear train in a direct manner that is suitable for a specific application. Stefan Staicu in his paper, “Inverse dynamics of a planetary gear train for robotics” states that recursive matrix relations concerning the geometric analysis, kinematics and dynamics of a Bendix wrist planetary bevel-gear train 8
for robotics are established in the paper. The prototype of this mechanism is a 3DOF system with seven links and four bevel gear pairs controlled by electric motors. Supposing that the rotational motion of the platform is known, an inverse dynamic problem is developed using the principle of virtual powers. Some relations and graphs for torques and powers of three actuators are determined. A robot manipulator needs at least six degrees of freedom to manipulate an object freely in space. The first three moving links are used primarily for manipulating the position, while the second mechanism is used for controlling the orientation of the end-effectors. The subassembly associated with the last moving links is called the wrist, and their joint axes are often designed to intersect at a common point called the wrist centre. Planetary bevel-gear trains with three degrees of freedom are adopted as the design concept for robotic wrist. Bevel-gear wrist mechanisms are generally incorporated in the structure of the robots. Amemiya, T. (1984), in his paper says that the question of the location of exporters of manufactured goods within a country is investigated. Based on insights from new trade theory, the new economic geography (NEG) and gravity-equation modeling, an empirical model is specified with agglomeration and increasing returns (the home market effect) and transport costs (proxied by distance) as major determinants of the location decision of exporters. Data from 354 magisterial districts in South Africa are used with a variety of estimators (OLS, Tobit, RE-Tobit) and allowances for data shortcomings (bootstrapped standard errors and analytical weights) to identify the determinants of regional manufactured exports. It is found that the home-market effect (measured by the size of local GDP) and distance (measured as the distance in km to the nearest port) are significant determinants of regional manufactured exports. This paper contributes to the literature. 9
Theoretical and empirical work in international trade has, with a few exceptions, predominantly focused on trade between countries, as opposed to focusing on where exports originate within a country. International trade theory until fairly recently assumed away all elements that might make consideration of the geography of exports possible. For instance, transport costs, distance, market size, scale economies and agglomeration were only recently incorporated into trade models. Moreover, where transport costs in international trade are concerned, empirical work has so far tended to focus on international shipping costs. Tadashi TAKEUCHI and Kazuhide TOGAI describes in their paper about Meshing transmission error (TE) is well known as a contributing factor of gear whine, but system- level prediction of transmission error and quantitative analysis of dynamic meshing vibromotive force have not been analyzed adequately until now. This paper describes the use of a computer- aidedengineering (CAE) model for the analysis of the dynamic gear meshing behavior and for the prediction of dynamic transmission error from the input torque of the system. This paper also describes the analysis of a dynamic vibromotive force at a bearing location where vibration is transmitted to the vehicle body. The gear whine critical frequency can be predicted with the proposed method at an early stage of passenger-car development when no prototype is available. Gear whine is an automotive quality problem that can be perceived by any driver regardless of his/her level of driving experience, but it tends to manifest itself in the final stages of vehicle development when, in most cases, effective design measures that can be taken against it are extremely limited. Consequently, power train designers have a great need for CAE technologies that enable them to predict gear whine using a virtual power train before the power train is physically constructed.
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Inputs to the transmission and other power-train elements in the vehicle include the engine torque and accompanying fluctuations, which are regarded as combustion- originated dynamic-excitation factors. These inputs, however, initiate only vibration within the growling-sound frequency range, not vibration at whine frequencies, which are much higher. If gear-tooth shapes were optimum and tooth meshing were perfect, the gears would transmit the input torque in a manner precluding the generation of frequency components other than those related to engine-torque fluctuations. In actual gear-tooth meshing, however, forced displacements resulting from meshing error causes meshing vibromotive forces to be generated during torque transmission. These vibromotive forces then constitute a source of vibration. Further, the complete power-train system includes shafts and cases whose stiffness has an influence on gear-tooth meshing in such a way that the meshing vibromotive forces have peaks at certain frequencies. Hiroyuki Kato, Ken Iwanami, Hiroshi Arai, Koji Asanotells describes in their paper, in addition to performance (running safety and stability, and riding comfort) compatible with great increases in driving speed, ensuring of reliability when running at high speeds, and use for service operation based on long term durability and ease of maintenance must all be considered. Therefore, configurations including use of new structural elements were reviewed for the main structural parts of the bogie. In addition to significant investigation of the strength and performance through numerical analysis at the investigation stage, a first prototype was built and performance tests and long term endurance tests through bench testing were performed for confirmation. Bogies for which development proceeded in this manner have been installed on a Shinkansen high speed test train and performance confirmation is being performed through actual running tests. Here, with regard to the development details and development process for the high speed Shinkansen bogie, the bogie and the
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main parts such as driving device, axle bearings, and brake components are mainly introduced. As described previously, the stiffness of the primary suspension for the bogie that has been developed has been reduced to improved vertical direction riding comfort; therefore, the displacement between the traction motor axle and the pinion axle has gotten large. Therefore, 2 types of axle couplings (gear type axle coupling and TD coupling) that have reduced rotation noise and that are compatible with this amount of displacement have been developed. Keith Hart in his paper describes that fluctuations in the balance of the relationship between impersonal and personal principles of social organization. This draws heavily on Max Weber’s interpretation of western history. The second part reviews the concept of an ‘informal economy/sector’ from its origin in discussions of the Third World urban poor to its present status as a universal feature of economy. The third part asks how we might conceive of combining the formal/informal pair with a view to promoting development. In conclusion I suggest how partnerships between bureaucracy and the people might be made more equal. We are asked to consider how the informal/formal pair might be linked more effectively for the purpose of development. They are of course linked already since the idea of an ‘informal economy’ is entailed by the institutional effort to organize society along formal lines. ‘Form’ is the rule, an idea of what ought to be universal in social life; and for most of the twentieth century the dominant forms have been those of bureaucracy, particularly of national bureaucracy, since society has become identified to a large extent with the nation-state. This identity may now be weakening as a result of the digital revolution in communications and neo-liberal economic policies (Hart 2001a). If there are to be new initiatives combining public bureaucracy with informal popular practices in complementary ways, we need to be aware of this historical context.
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The formal and informal appear to be separate entities because of the use of the term ‘sector’. This gives the impression that the two are located in different places, like agriculture and manufacturing, whereas both the bureaucracy and its antithesis contain the formal/informal dialectic within themselves as well as between them. The need to link the sectors arises from a widespread perception that their relationship consists at present of a class war between the bureaucracy and the people. It was not supposed to be like this. Modern bureaucracy was invented as part of a democratic political project to give citizens equal access to what was theirs as a right. It still has the ability to coordinate public services on a scale that is beyond the reach of individuals and most groups. So it is disheartening that bureaucracy (‘the power of public office’) should normally be seen now as the negation of democracy (‘the power of the people’) rather than as its natural ally. Forms are necessarily abstract and a lot of social life is left out as a result. This can lead to an attempt to reduce the gap by creating new abstractions that incorporate the informal practices of people into the formal model. Naming these practices as an ‘informal sector’ is one such devise. It appears to be informal because its forms are largely invisible to the bureaucratic gaze. Mobilizing the informal economy will require a pluralistic approach based on at least acknowledgement of those forms. Equally, the formal sphere of society is not just abstract, but consists also of the people who staff bureaucracies and their informal practices. Somehow the human potential of both has to be unlocked together.
2.2 Conclusion Taking the idea from all research paper which are included in the literature review. We came to a point that by using gear-train mechanism we can make a system which is used to open the nut of a wheel with minimum torque so, as to eliminate the hard-work of person with minimum time. In all research paper 13
idea is given that how gear train works, and how the power transmission take place.
Selection of material Literature collection
Information collection Selection of material
Designing of various components
Selection of manufacturing process
Future works
Fig. 1 Literature is deeply studied and the useful information is collected, then we have to select the various material that are to be used for the various components of the unified wheel opener. Then the designing of the various components is done so that each and every component will serve its proper function and it will not fail after words. Then how to manufacture the different components or the various manufacturing processes that are to be used to manufacture the components are then studied. The fig. below shows the various steps included in the project work. 14
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CHAPTER-3 METHODOLOGY 3.1 CAD DIAGRAM The design of the MULTI NUT REMOVER AND TIGHTENER is performed by commercial computer aided design (CAD) software as shown by Figure 1.
Fig. 1.Multi nut remover conceptual design. Several static load analyses are also performed in order to find the safety factor of the design. Theoretical calculation analysis is carried out with the purpose of validation. The force required for removing four numbers of nuts is, F = 4τ / (lRG)
(1)
In the fabrication of Multi nut removing tool, two processes are performed; milling and fitting. Since the gears are not available in the market, custom designed gears need precision milling and fitting processes. Once the tool is ready, an experiment is performed with the intention to find the time required to remove the nuts. This result is then compared with the time required 16
using ordinary L-shaped wrench. Experiment using impact wrench is also performed.
Fig-2: Analysis of Gear The analysis of the tool is performed with design parameters and analyse the gear in static structural. To estimate the force exerted on the body. ANSYS WORKBENCH 16 software used to achieve the study objectives.
CHAPTER-4 17
MATERIAL SELECTION 4.1 Introduction To Engineering Materials The selection of a material for a particular application is governed by the working condition to which it will be subjected, ease of Manufacturing and the cost considerations, pure metals find few applications in pure condition and secondly they generally have poor strength in pure form. Various desired and special properties can be achieved by addition of different material to form alloys. Alloy comprises of a base metal and one or more alloying elements. The typical properties associated with working condition are tenacity elasticity toughness and hardness, toughness and typical properties associated with manufacturing process is ductility, malleability and plasticity. The various properties can be determined by testing techniques e.g. tensile test resistance to abrasion by hardness test toughness by impact test and other special properties like fatigue and creep test. 4.2 Engineering Material For Product Design All physical objects are made out of some material substance or other. Mother Nature has her own set of building material for the objects of her creation, living or non-living. Over the millennia, man has observed and adapted many of these for making objects of his invention and design. For engineering purposes, we now use a very wide spectrum of materials. These generally fall under the following categories: Materials as found in nature used after only very minor preparation such as cutting to size, sun-drying, mixing with water. Some examples are coal, wood and stones. Natural materials that are modified/ refined before use through some physical, chemical or thermal processes that improve their utilization.
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Synthesized materials that are rarely found freely in nature. These are derived from one or more natural raw materials through major transformation processes. Most of the materials used in modern mechanical engineering belong to this category. 4.3 Selection Criteria The designer selects the materials of construction for his product based on several criteria such as its cost, the desirable properties that it should possess, its availability, the preferred manufacturing processes that are to be employed, etc. The overall economy is influenced by all these factors. In special cases, essentiality and /or urgency of the need for the product can supersede the economic considerations. The main criteria for material selection are discussed below: 4.3.1 Cost Of The Material The amount of raw materials, their composition, quality, any special heattreatment that is required, etc. influence the unit cost of materials. The unit cost generally depends also on the quantity of raw material that is purchased in a single lot. Special steel materials, for example, cost much more in the market when purchased in small quantities from a retailer than in bulk directly from the steel mill/stockyard.
4.3.2 Availability The material should be readily available in adequate quantities. Material availability is closely linked with the variety and level of technology obtained in a given geographic location. Procuring materials from far and wide can be expensive, due to the additional cost for transport, for transporter taxes and duties etc. 4.3.3 Manufacturing Process
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Facilities for shaping and treating the selected material into the finished product or component must be available for economic production. Otherwise, the production cost goes up. For example, the selection of forged alloy steel for a connecting rod design necessarily assumes that a suitable forging facility is available along with the necessary dies and other accessories. If the alloy is of a rare quality, then facilities for its heat treatment might not be available. 4.3.4 Properties Of The Material The desired function and performance of any product depends to a great extent on the use of materials with the right physical and chemical properties. In general mechanical engineering these properties can be classified into different categories depending on how a particular property affects the function and life of a component. The main property groups are: Chemical Composition, specifying the contents of all the different elements contained. Properties of state, such as solid, liquid or gas, density, porosity, temperature. Strength related properties, such as ultimate strengths in tension, compression and shear, yield strength/ 0.2% strength, fatigue strength, notch sensitive, hardness, impact strength, effect of high/low temperatures on strength, etc. Strain related properties, such as elongation at fracture, elastic moduli, ductility, malleability etc. these help to ensure the desired rigidity/ elasticity, formability etc. Wear related properties, that determine the erosion, abrasion, friction etc. between components in contact/ relative motion. 4.4 Selection Of Material Carbon steel is an alloy of iron and carbon with varying quantities of phosphorus and sulphur. To this alloy is added a deoxidizer to remove or 20
minimize the last traces of oxygen. Manganese is added to such an alloy to neutralize sulphur, either alone are in combination with silicone or other deoxidizers. In carbon steel the maximum content of the following elements does not exceeding the limits given against each: Manganese
…..
1.65%
Silicone
…..
0.60%
Copper
…..
0.60%
The elements which are specified and are added into the carbon steel are carbon, manganese, phosphorus, sulphur and silicon. The effect of these elements in carbon steel is given below: CARBON contents are very important in determining the properties of steel. The tensile strength of steel increases with increase in carbon contents up to 0.83% and beyond this it drops quickly. Hardness increases as the carbon contents increases. Ductility and weld ability decreases with increase in carbon contents. Manganese: Tensile strength and hardness increases with increase in manganese content weld ability decreases by increase in manganese. Manganese content in steel varies from 0.2 to 0.8%. Phosphorus: Tensile strength and hardness increases with increase in phosphorus content. The phosphorus content in steel varies from 0.005 to 0.12% and maximum content permitted is 0.4%. In low phosphorus steel, phosphorus steel, phosphorus is dissolved in matrix and in others it appears as phosphate precipitate. Sulphur: Sulphur in steel lowers the toughness and transverse ductility, Sulphur imparts brittleness to chips removed in machining operations. The maximum permitted contents of sulphur in steel is 0.055%. 21
Silicon: It is the principal deoxidizer used in the carbon steel Presence of silicon in steel promotes increase of grain size and deep hardening properties. Its addition is very useful in making steel adaptable for case carburizing. Presence of the silicon varies from 0.1 to 0.35%. Copper: Though it is not an essential constituent of carbon steel yet it is added up to 0.25% to increase the resistance to atmospheric corrosion. The most important composition for carbon used as engineering material having carbon % 0.02 to 0.30. Their merchantability is quite good. Such steel are used in making small forging, crank pin, Gear, Valve, Crank shaft, railway axles, cross head, connecting rods, rims for turbine gears, armature shafts and fish plates. 4.4.1 Stainless Steels Stainless steel is iron base alloy that has a great resistance to corrosion. It is observed that a thin, transparent and very tough film forms on the surface of stainless steel which is inert or passive and does not react with many corrosive material within a temp range of 235 0C to 9800C, it exhibits strength, toughness and corrosion resistance superior to other metals. It is just ideally suited for handling and storage of liquid helium, hydrogen, nitrogen and oxygen that exist at cryogenic temp. The property of corrosion resistance is obtained by adding chromium only or by adding chromium and nickel together. Stainless steel is manufactured in electric furnaces. 4.4.2 Cast Iron Cast iron is a general term applied to wide range of iron carbon alloys. Their carbon contents are such as to cause some liquid of eutectic composition (called ledeburite) to solidify. The minimum carbon contents are therefore about 2% while the maximum is about 4.3%. Cast iron should not be thought of as a metal having single element. It, at least, possesses six elements. These are iron, carbon, silicon, manganese, phosphorus
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and sulphur. Alloy cast iron has still other elements, which have important effect on its physical properties. 4.4.3 Mild Steel Plain carbon steel in which carbon contents ranges from 0.08 to below 0.3 are known as mild steel. Those mild steel in carbon contents is less than 0.15% are known as dead mild steel. Mild steel are not such effected by heat treatment processes, especially hardening process. A decrease in carbon content improves the ductility of mild steel. These steels possess good machinability and weldability. The are mainly used for making wires, rivets, nut, bolt, screw, sheets, plates, tube, roads, shafts, structural steel section and for general workshop purposes etc.
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CHAPTER-5 DESIGN PROCEDURE 5.1 Design And Product Cycle All engineering activities necessarily begin with some ideas with high or low innovative content, translated into definite plans for their realization in the form of products. This is the essence of design engineering. The ultimate success depends on a thorough consideration of how the product will be made and used as well as on the attention to detail paid by the design engineering. This is applicable equally for a minor redesign of a existing product or for a most innovative one. A good understanding of how the various phases of the product cycle can influence the design is therefore Essential. The Product Cycle can be better understood by fig. 1.
5.2 The Challenges Of Design Engineering The present day industry bases economy is founded on the consumption of as many different products as possible by as much number of users as possible. It serves as an engine driving technology. The numbers put manufacturing under pressure; the numbers as well as the variety put greater pressure on design engineering. This is manifested by Short time available for design, development and testing of the product before it reaches the user. Demands from the users for affordable cost combined with high quality of performance and appearance. Increasing number of competition who can supply a product of equivalent
value. On one side, the scientific cooperation and exchange of information have become international. On the other side, industrial activities and communications network have become globalized. Given the present day
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ease of access to technology, major break through in product innovation and design are not really essential for industries to produce and prosper. Market/Needs Tasks
Potential & Aims of Organization
Product-Planning/ Definition of Task Development/Design
Manufacture/Assembl y/Testing Marketing/Application Engineering, Sales Use/Consumption/ Maintenance
Waste Products/ Obsolete Products Life Cycle of a Product Fig. 1
5.3 Qualities Of A Good Design A good product design should satisfy the expectations of the customer/user. These can be summarized in the following conditions. The product must 25
Carry out the desired functions reliably. Appeal both technologically and psychologically. Be economical to acquire and to use. Be easy and safe to use. Be easy to maintain in working order. In order to ensure the conditions, not only must the design concept be novel and sound but the design must be well engineered. This engineering part of design consists of Drawing up the main parameters for function and performance. Deciding the material, shape and dimensions of the components. Ensuring that the component dimensions satisfy the functional and strength requirement. Ensuring the feasibility to manufacture or otherwise procure all the necessary components, assemble them together and test them. Preparing the component and assembly drawing for guiding manufacture and inspection. 5.4 Introduction To Design Spanners are used to open the wheel. Spanners in the use are of various types. The different kinds of spanners in use are shown in figure One thing is very common for all these spanners: only a single nut is opened in a single time. This causes wastage of precious time and since to open all the nuts spanner is to engaged and disengaged again and again till the last nut is unscrewed or screwed. Thus in this work a large amount of power is required to perform the requisite operation below Fig. 2
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Four way wheel Spanner
Telescopic spanner
Angular Spanner
Box Spanner Fig.2 Types of Spanner
Multi nut remover These disadvantages are removed in multi nut remover. The idea is to reduce time when release the wheel or put it on. By using this device, wheel nuts can be opened simultaneously at one time. The supposed design of the 27
unified wheel opener is shown below. On pictures, we can see handle, casing/gears housing, and wheel nut connectors. Wheel nut connectors are connected to wheel nut, and the number of connector depends on the number of studs. So it will be different according to wheel type and size. Inside the Casing, there are simple gears mechanisms, causing one rotation of The Handle to make two rotations of the wheel nuts. 5.5 Designing Abbreviations Used: m M DP DG Dg WT WR YP σ T Te Tp Tg
Module bending moment Pitch circle diameter of pinion Pitch circle diameter of gear Diameter of gear shaft Tangential load Resultant load Lewis form factor Allowable stress Twisting moment Equivalent twisting moment Number of teeth on pinion Number of teeth on gear
5.6 Design Procedure For Gear & Pinion: Torque required for one nut
= 70N-m
Total torque required
= 4×70N-m = 280N-m
Let input torque
=30N-m
Maximum Tangential force on pinion (WT) =2×Ti/DP =2×30×1000/18 28
=1333.3N For 200 stub teeth system, Lewis Factor for pinion, Yp = 0.175-(0.841×m/18) = 0.175-(0.047×m) For EN8 Mild Steel σ = 750MPa We know that, Assume Module, (m) =2.7mm Now, as we know Number of teeth on pinion (Tp) = Dp/m Also, Number of teeth on gear (Tg) =Dg/m Therefore, Tp = 50/2.7 = 18 Tg = 60/2.7 = 22 Other dimensions for pinion &gear are as: Addendum
=0.943×m=2.546
Dedendum
=1.257×m=3.393
Minimum total depth
= 2.200×m = 5.94
Minimum clearance
=0.314×m=0.848
Backlash
= 0.157×m = 0.424
Thickness of tooth
= 1.493×m =4.031
Outside diameter of pinion
= (Tp+2 )×m =54
Outside diameter of gear
= (Tg+2) ×m = 64.8
5.7 Design For Pinion Shaft Normal load acting on pinion’s tooth, (Wn ) = WT/ CosØ = 1333.3/cos200 =1418.86N 29
Weight of pinion (Wp) = 0.00118Tp×b×m2 = 2.55N Therefore, resultant load on pinion (WR) = = (Wn2+Wp2+2×Wn×WpCosØ)0.5 = 1421.19N Assuming pinion is overhung on shaft at 600 mm Bending moment on shaft due to WR is M M = WR×60 = 1421.19N ×60 = 85271.8N-mm And twisting moment on shaft due to WT is T T = WT×Dp/2 =66665N-mm Equivalent twisting moment is Te = (M2+T2)0.5 = 108237.9N-mm Let dp be the diameter of pinion shaft dp = ×ζ×Dp3 =×3.74×10^-5×50^3 =14.7or 15mm (say) 5.8 Design For Compound Shaft Normal load acting on pinion tooth, (Wn) = WT/CosØ =1333.3/Cos200 =1418.86N Weight of pinion WP=0.00118×Tg×b×m2 = 6.96N Therefore, resultant load on pinion, WR = (Wn2+Wp2+2×Wn×Wp×CosØ)0.5 WR = 1425.4N Assuming pinion is overhung on shaft at 30mm Therefore bending moment on shaft due to WR is (M)=WR×30=1425.4×30 = 42762.06N-mm And twisting moment on shaft due to Wt is T T = WT×Dg/2 = 1333.3×60/2 =40000N-mm 30
Equivalent twisting moment is Te Te = (M2+T2)0.5 = 58554.2N-mm Let dg = Diameter of gear shaft. As, Te
= ×ζ×dg3/16
58554.2
= ×110×dg3/16
So, dg =13.9mm or 14mm (say) 5.9 Design For Output Shaft Max. Tangential force on output gear, WT’ = (WT×Dg/Dp) = 1600.05N Normal load acting on tooth, Wn = WT’/CosØ =1600.05/Cos200 =1702.73N Weight of gear, WP =0.00118×Tg×b×m2 =0.00118×22×13.5×2.72 =2.6N Therefore resultant load on gear, WR = (Wn2+Wp2+2×Wn×Wp×Cos Ø)0.5 = 1705.17N Assuming gear is overhung on shaft at 5mm Therefore bending moment on shaft due to WR is M M = WR×5 = 1705.17×5 = 8525.86N-mm And twisting moment on shaft due to WT is T 31
T = WT×DG/2 = 1600.05×60/2 = 48001.5N-mm And equivalent twisting moment is Te, Te = (M2+T2)1/2 = 48752.8N-mm Let dG = Diameter of gear shaft, Let Te
= (/16)×ζ×dG3
48752.8 = (/16)×230×dG3 So, dG = 36.5 mm or 37 mm(say) All the component are designed to serve their functions properly and taking into account the various consideration such as material, labour, availability of technology, economic, safety, usage, reliability, maintainability, functionality etc. These components will be manufactured according to their design specifications.
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CHAPTER-6 EXPERIMENTAL SETUP 6.1.FABRICATION AND EXPERIMENTATION: Assembly as shown in fig. it consists of four gear and central pinion for input. Pinion is a driving member. These gears are mounted on base plate by using nut and bolt arrangement. The tool is made of medium carbon steel. A spanner holder is directly attached with the driven gears. Grease is used to reduce wear, tear and heat of friction from mating gears. Once the tool is assembled, a layer of paint is applied to finish the surface and protect from corrosion. 6.1 Component of assembly 1. Gear 2. Base plate or rod 3. Spanner Box 4. Central shaft with spanner box. In fig1.shows the EN8 Mild steel
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Fig.1 Gears
In fig.2 shows the Fig.2. Base plate or rod mild steel
Fig.3. Spanner Box 34
base
rod
of
Fig.4. Central shaft with spanner box
CHAPTER-7 MANUFACTURING PROCESS 7.1 Gears The commonly used generating processes used for the generation of gear teeth are:1. Gear Shaper Process 2. Rack Planning Process 3. Hobbing Process. 7.1.1 Gear Shaper Process In this process a pinion shaped cutter is used which carries clearance on the tooth face and sides. It carries a hole in the center for mounting on the stub arbor or spindle of the machine. The cutter is mounted with the axis vertical and is reciprocated up and down by sliding the spindle head along the vertical ways on the machine. In addition to the reciprocating motion, the cutter and the gear blank both are rotated slowly their own axis. The relative speed of rotation of the two is the same as the gear to be cut will have with a pinion of the same number of teeth as the cutter. It is accomplished by providing a gear train between the cutter spindle and the work spindle. The cutter in its rotation generates the tooth profile on the gear blank. All gears cut by the same cutter will mesh correctly. This is a specific advantage of this process over the forming process using rotary cutters. Also it is a much faster process than rotary cutting. 7.1.2 Gear Planning 35
In this process rack type cutters for generating of spur. Involutes rack has straight edges and sharp corners and hence can be manufactured easily and accurately. The cutters generate as they are cut and as the name implies, the machine cuts the teeth by reciprocating planning action of the cutter. This is a true generating process since it utilizes the principle that an involute curve can be formed by a straight generator when a gear blank is made to roll without slip relative to the generator. 7.1.3 Gear Hobbing In this process, the gear blank is rolled with a rotating cutter called the HOB. A majority of the involue gears are produced by this method. A gear hob looks like a worm, but carries a number of straight flutes (gashes), cut all around, parallel to its axis. This results in the production of separate cutting teeth and cutting edges. In operation, the hob is rotated at as suitable speed and fed into the gear blank. The blank also rotates simultaneously. The speeds of the two are so synchronizes that the blank rotates through one pitch distance for each complete revolution of the hob. There is no intermittent motion of the two and the generating continues steadily. The hob teeth are just like screw threads, i.e. having a definite helix angle. The hob is, therefore tilted to its own helix angle while cutting the gear so that its teeth are square with the blank and produces a true involute shape. 7.1.4 Gear Milling Milling is one of the metal removal process best known for making gear. Here a firm cutter is passed through the gear blank to affect the tooth gap, helical gear, worm & worm wheel and bevel gear can be manufactured by milling. Gear milling is less costly and less accurate process and it is employed for the following: Coarse pitch gear Racks of all pitches Worms 36
Toothed parts as sprockets and ratchets. The production capacity in this method is low since each space is machined separately and the time is lost in retuning the job to its initial position and in indexing for each tooth. In actual practice a series of cutters are selected for a number of teeth to be milled. Out of all above processes we select the Gear Shaping for the manufacturing of all the gears. The various reasons for selection of this process are as following:1. This process of making gears is cheaper than hob cutter. 2. Gear shaping machines are easily available. 3. All gears can be made of same pitch by same cutter. 7.2 Axles In the manufacturing of the axles following operations are used: Turning Facing Grinding Grooving Drilling Parting Off Assembly 7.2.1 Turning It may be defined as the machining the operation for generating external surfaces of the revolution by the action of the cutting tool on a rotating work piece. When the same action is applied to internal surfaces of the revolution, the process is termed as boring. 7.2.2 Facing Facing operation machines the ends of the work piece. It provides a surface which is square with the axis of the work piece from which to start the job. 37
Facing is done by feeding the cross slide or compound in or out. In facing the cutting tool moves from the center of the job towards its periphery and vice – versa. Facing is primarily used to smooth off a saw- cut end of a piece of bar stock or to smooth the face of rough casting. 7.2.3 Grinding It is carried out while the work is rotating on the lathe. Filling is often restored to when Only a very small amount of stock is to be removed from a diameter. For removing sharp corner on the work piece. Filling is a hand operation. A clean, sharp, single cut mill file of 200 or 250 mm length is held in the hand and the file flat is placed on the work near the left end of the part to be filled. The file is held at a slight angle and not at right angles to the work piece. For carrying out of the filling operation, the file is pressed lightly on to the work piece and moved forward so that the work piece rotates by 2 or 3 revolutions during the forward or cutting stroke of the file. Pressure on the file is relieved during its return strokes but its movement overlaps the cut made by the file during the cutting stroke. Generally long strokes are taken and the file is cleaned frequently with the file card. 7.2.4 Grooving Work pieces on which threads are to be cut close to a shoulder are usually undercut or grooved to make threads cutting somewhat easier. Diameters which are to be ground up to a shoulder are usually undercut so that the grinding wheel will not leave a small radius in the corner. Grooving operation reduces the diameter of the work piece at a narrow surface near the shoulder etc. The grooving tool is fed into the revolving work piece at right angle to it using cross-slide hand wheel.
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7.2.5 Drilling Drilling is the process of making holes in a work piece. Either the work piece rotate or drill is stationary or vice-versa. When drilling on the lathe is being done, generally the work piece rotates in the chuck and the drill held in the tail stock is fed into the work piece by means of the hand wheel on the outer end of the tail-stock assembly. It is possible to do drill by holding and rotating the drill in the lathe spindle while keeping the work stationary, supported by a special pad mounted in tail-stock quill. Since drill feed is by hand, care must be taken, particularly in drilling small holes. Coolant should be withdrawn occasionally to clear chips from the hole and to aid in getting coolant to cutting edges of the drill. 7.2.6 Parting Off Parting off operation separates the finished work piece from the bar from which the work piece was machines. Partings off tools are ground to cut on the end only as they are fed into the work piece. Since the tool is comparatively thin and delicate and care must be taken when feeding it into the work otherwise it may break. The finished work piece should be such that it is parted as close to the head stock as possible. 7.3 ASSEMBLY Bearing seats are assembled on base plates with the help of nuts. Bearings are fitted in their respective seats. Bushes are also fitted at their respective positions. Studs are tightened at their positions on lower base plate. Now output shaft is fitted in bearing on lower base plate. Compound shaft is fitted in such a way so that pinion of compound shaft correctly meshes with output shaft’s gear. Adjustments are made with the help of shim and packing. Now input shaft is fitted on upper pinion gear. Pinion is fitted on input by lock pin. Sprockets are welded on their shafts. Now these shafts are assembled on lower base plate with the help of circlips. Clearance is adjusted by the help of shim. Upper base plate 39
containing input shaft is fitted on the lower base plate. Center distance between the two base plates is adjusted with the help of lock nuts at all the corners. Sprocket is assembled on output shaft with the help of key. Roller chain is mounted on all the four sprockets and chain is locked by chain lock. 7.4 MATERIAL PURCHASE Rust of the part of Multi nut remover are purchased from market,which constitutes the different material of different parts according to our requirement. All these parts are purchased by suggesting with mechanic. Material purchased are bearing, plate, key, sleeve, Anchor nuts, Handle.
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CHAPTER-8 FUTURE WORK 8.1 Future Work As the time period in a semester is limited therefore we have only studied all the facts about the Multi nut remover such as material required, designing of each component, selection of manufacturing process, cost consideration, reliability etc. and in the next semester based on this critical data. The fabrication of the Multi nut remover will be carried out. The different component of Multi nut remover will be manufactured and checked for suitability, and then this component will be assembled to make the tool Multi nut remover. Then it will be installed and its working will be checked.
8.2 CONCLUSION In this research, the design and fabrication of multi nut remover is proposed. The static load analysis is performed. The fabrication of multi nut remover is completed by milling, welding and fitting processes. The multi nut remover is successfully manufactured and fully functional either tested manually using lever or by using impact wrench. From the results of analyses and experiments, the tool is possible to be improved and prototyped for mass production. For future development and improvement of the multi nut remover, light and strong material is expected to be available and applied.
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REFERENCES
[1] Different tools, Source: http://www.williamtool.com. [2] Dr. P.C. Sharma- A text book of production technology-1996 [3] Fasteners, Source: http://www.laytonfasteners.com. [4] Gordon R. Pennock and Jeremiah J. Alwerdt, “Duality between the kinematics of gear trains and the statics of beam systems”, Science direct journal, Volume 42, page 1527-1546 [5] Hiroyuki Kato, Ken Iwanami, Hiroshi Arai, Koji Asanotells, “Running safety and comfort”, International journal, Volume 28, page 541-578 [6] Ligang Yao Jian S. Dai Guowu and Yingjie, “Meshing characteristics of toroidal drive”, Science direct journal, Volume 47, page 827-854 [7] Nuts and bolts standards, Source: http://www.nutsandboltsstandings.com. [8] PSG design data book, Second edition-1999 [9] Shigley.J.E and Mischke C.R. - Mechanical Engineering Design-2008 [10] Stefan Staicu, “Inverse dynamics of a planetary gear train for robotics”, Research gate journal, Volume 47, page 728-767 [11] Tadashi takeuchi and Kazuhide togai, “Meshing transmission error”,Scribd, digital
document
library,Source:
http://www.scribd.com/doc/GearWhine-
Prediction-With-CAE-for-AAM [12] V.B.B. Bhandari, “Design of machine elements”, Second edition-1994 [13] Wen-Hsiang Hsie, “An experimental study on cam- controlled planetary gear trains”, Science direct journal, Volume 24, page 513-525.
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