行星輪增速雙人自行車設(shè)計-帶答辯ppt【含三維UG模型】【含4張CAD圖紙】

行星輪增速雙人自行車設(shè)計-帶答辯ppt【含三維UG模型】【含4張CAD圖紙】,含三維UG模型,行星,增速,雙人,自行車,設(shè)計,答辯,ppt,三維,ug,模型,cad,圖紙 外文文獻(xiàn) Mechanical Design Abstract: A machine is a combination of mechanisms and other components which transforms, transmits, or utilizes energy, force, or motion for a useful purpose. Examples are engines, turbines, vehicles, hoists, printing presses, washing machines, and movie cameras. Many of the principles and methods of design that apply to machines also apply to manufactured articles that are not true machines, from hub caps and filing cabinets to instruments and nuclear pressure vessels. The term "mechanical design" is used in a broader sense than "machine design" to include their design. For some apparatus, the thermal and fluid aspects that determine the requirements of heat, flow path, and volume are separately considered. However, the motion and structural aspects and the provisions for retention and enclosure are considerations in mechanical design. Applications occur in the field of mechanical engineering, and in other engineering fields as well, all of which require mechanical devices, such as switches, cams, valves, vessels, and mixers. Keywords: Mechanical Designmechanisms Design Process Tolerance An overview of mechanical design The first step in the manufacture of any product is design. Mechanical design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the original conception of the product in terms of its size, shape and construction details, but also considers the various factors involved in the manufacture ，marketing and use of the product. People who perform the various functions of machine design are typically called designers, or design engineers. Mechanical design is a creative activity. However, in addition to being innovative, a design engineer must also have a solid background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes. Here we take the selection of materials as an example. During recent years the selection of engineering materials has assumed great importance. Moreover, the process should be one of continual reevaluation. New materials often become available and there may be a decreasing availability of others. Concerns regarding environment pollution, recycling and worker health and safety often impose new constraints. The desire for weight reduction or energy savings may dictate the use of different materials. Pressures from domestic and international competition, increased serviceability requirements, and customer feedback may all promote materials reevaluation. The extent of product liability actions, often the result of improper material use, has had a marked impact. In addition, the interdependence between material and their processing has become better recognized. The development of new processes often forces reevaluation of the material being processed. Therefore, it is imperative that design and manufacturing engineers exercise considerable care in selecting, specifying, and utilizing materials if they are to achieve satisfactory results at reasonable cost and still assure quality. In mechanics processing，milling and grinding are always under the consideration of the designers. With the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of the milling process merits the attention and consideration of designers seriously concerned with the manufacture of their product. Grinding is one of the most widely used methods of finishing parts to extremely close tolerances and low surface roughness. Currently, there are grinders for almost every type of grinding operation. Particular design features of a part dictate to a large degree the type of grinding machine required. Where processing costs are excessive, parts redesigned to utilize a less expensive, higher output grinding method may be well worthwhile. For example, wherever possible the production economy of center less grinding should be taken advantage of by proper design consideration. Although grinding is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down form rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense. Besides, the application of nontraditional manufacturing processes will bring more bold and innovative design. The conventional manufacturing processes in use today for material removal primarily rely on electric motors and hard tool materials to perform tasks such as sawing, drilling, and broaching. Conventional forming operations are performed with the energy from electric motors, hydraulics, and gravity. Likewise, material joining is conventionally accomplished with thermal energy sources such as burning gases and electric arcs. In contrast, nontraditional manufacturing processes harness energy sources considered unconventional by yesterday’s standards. Material removal can now be accomplished with electrochemical reactions, high-velocity jets of liquids and abrasives. Materials that in the past have been extremely difficult to form, are now formed with magnetic fields, explosives, and the shock waves from powerful electric sparks.. Material-joining capabilities have been expanded with the use of high-frequency sound waves and beams of electrons. In the past 50 years, over 20 different nontraditional manufacturing processes have been invented and successfully implemented into production. The reason there are such a large number of nontraditional processes is the same reason there are such a large number of conventional processes ; each process has its own characteristic attributes and limitations, hence no one process is best for all manufacturing situations. In other cases, nontraditional processes are used to reduce the number of rejects experienced by the old manufacturing method by increasing repeatability, reducing in-process breakage of fragile work pieces, or by minimizing detrimental effects on work piece properties. As stated previously, the purpose of mechanical design is to produce a product which will serve a need for man. Inventions, discovery and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived. It should be recognized, therefore, that a human need must be identified before a particular product is designed. Mechanical design should be considered to be an opportunity to use innovative talents to envision a design of a product, to analyze the system and then make sound judgments on how the product is to be manufactured. It is important to understand the fundamentals of engineering rather than memorize mere facts and equations. There are no facts or equations which alone can be used to provide all the correct decisions required to produce a good design. On the other hand, any calculations made must be done with the utmost care and precision. Good design require trying new ideas and being willing to take a certain amount of risk, knowing that if the new idea not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated. During the beginning stages of design, creativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which is ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise. Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Initially, the designer must communicate a preliminary design to get management approval. This is usually done by verbal discussions in conjunction with drawing layouts and written material. To communicate effectively, the following questions must be answered :(1) Does the design really serve a human need?(2) Will it be competitive with existing products of rival companies?(3) Is it economical to produce?(4) Can it be readily maintained?(5)Will it sell and make a profit? Design Process The design begins from real of or the demand of imagination. The existing instrument may need to take in to improve on the enduring, efficiency, weight, speed or the cost. May need new instrument to complete before function done by person, such as Assemble or maintain. The target is all or partly after making sure, design of the next move is to conceive outline the organization that can complete the function needed and it arranges for this, drawing grass diagram to be worth barehanded biggest, it isn't only one personal record of viewpoint with others discussion of assistance means, and be suitable for to communicate with own viewpoint particularly, is the stimulant which creates sex way of thinking to still need extensive knowledge concerning parts, because a the set new machine usually from be familiar with of each kind of spare parts reschedule or substitute but become, changed size and material perhaps. Regardless at conceive outline process in still after, a design will carry on a fast or rough calculation or analyze to make sure regulation size and possibility. When some concerning need or can use amount of space of viewpoint assurance after, can start pro rata painting grass diagram. Finally, I completed according to the design of the function and the credibility, can make kind machine. If test satisfied, and if the device wants mass production, will to the first design carry on a certain modification to insure with lower cost mass-produce. Later on several years of make and use a period, design probably because of conceive outline new viewpoint perhaps according to test and experience foundation of further analytical the change shown but change. Sell attraction, customer's satisfaction and manufacturing costs to all have something to do with design, the success which designs ability and engineering investment is closely related. Some design standards At this part, someone suggests the attitude of the usage creation carries on of analysis, this kind of analysis can cause a graveness improvement and to back up the product conceive outline with perfect, perhaps the product function is more, more economic and more enduring. Creating the stage's needing not is first with independent stage. Although analyze personnel the whole probably irresponsible design, he isn't only the right answer of[with] problem that can be from the numeral put forward wanting him to resolve only, not only is give should dint value, the size works to limit perhaps. He can put forward more extensive views, for the purpose of improvement norm or project. Because in the analysis the front or the analysis the process, he will acquaint with to equip and its work condition, he is fully placed in a beneficial position which conceives outline to choose a project. Best he can put forward a suggestion change shape to Elimination moment of force or should dint concentration, not allow to set up to have to cut the organization that noodles and excessive dynamic state carry a lotus greatly best is he discards his meticulous of design but is not see a machine discard afterwards. For stiring up to create sex thinking, the suggestion designs a personnel and analytical the personnel use following standard.6 ex- standards are particularly applicable to an analysis personnel, although he may involve to all this 10. 1. Create the physical function that sex land utilization need when using combine the control don't need. 2. Know practical carry lotus and its importance. 3. Consider in advance there is no function carrying a lotus. 4. Invent to add to carry a condition more beneficially. 5. Provide minimum weight the most beneficial of distribute in response to the dint with rigid. 6. Use a basic and square distance calculation a comparison and make size superior to turn. 7. Select by examinations material to acquire a function combination. 8. At spare parts and integrated spare parts careful choice. 9. Modify a function design with the orientation production line and decline low cost. 10. Consider to make parts accurate to position in the assemble with each other not interference Mechanical Design The whole machine design is a complicated process. Designing the personnel have to at thus of realm, such as calm down mechanics, kinetics, dynamics and material mechanics have good cultivated manners, have to also acquaint with manufacturing material and make a craft in addition. Designing the personnel has to can combine all related facts, carrying on Teaches Wei and creating grass diagram and graphics to come to deliver the manufacturing request to the car. The square one that any product designs works it an is the material that the choice used for making each parts. The design personnel of today can get an innumerable. While choosing, function, external appearance, material cost and manufacturing costs of product are all very important. Had to be careful to evaluate the function of material before any calculation. It is necessary a careful calculation with the usefulness of insuring the design. Compute to never appear on the diagram, but from ten various reason be saved. Once the whichever parts loses efficacy, will clear up to do what while designing this defective spare parts at the beginning; And, can acquire an experience document from compute past item. While needing the design for ising similar to, the past record will have a tremendous help. The check of computing(with diagram top size) is the most important.A decimal point's mislaying position can ruin an original and acceptable item. For example, if a person wants to design a bracket that can prop up 100 pounds, but it should can prop up 1000 pounds originally, the result affirmation will fail. The square aspect noodles had to check a check to design again a work. The calculator speaks to is an of great use tool for the staff member, can ease a dull calculation and provide to expand analysis to the existing data. Hand over system to make the calculator assistance design(CAD) with each other according to the calculator function and the calculator lend support to a manufacturing(CAM) to make possible.Pass thus of system, may conceive outline a first step to deliver to beat bore paper to take to used for numeral to process control but need not to draw formal construction diagram. The machine design for the laboratory test, model and kind machine is very helpful. The laboratory provided a lot of build up basic concept need of information, however, can also acquire with them some concerning product how on the spot would the understanding for working. Finally, a design personnel of success should offer the step that the utmost effort keeps up with ages. Will appear new material and produce a method everyday. If painting and design personnel's don't acquainting with modern method and material may put out action. A good design personnel should usually read technique periodical to keep up with a new development The engineering work is bad The solid is made sure boundary by its surface boundary. Typical model ground, design a personnel to specify Mr. to call size to a spare parts to make it contented its demand. Actually because of the surface irregular and proper surface rough degree, each spare parts can't make into Mr. to call size's hasing to allow size to have some varieties can make with insuring repeatedly. But, the variety allowed can't certainly too big with as for make to assemble the function of the piece to become bad. Single the variety allowed by spare parts is called business trip. Business trip this technical term not only is applicable to from the acceptable scope of the parts size of [with] manufacturing craft creation, but also is applicable to a machine or processes of exportation. For example, a give already set number of thepower each pedestals of I.C. engine have variety. Actually, we usually discover this kind of variety model will be a frequency to distribute curve, for example t. The distributes.(call the Gauss distribute again)One of the work which designs a personnel is the variety which specifies size for a spare parts and allows, this value canproduce acceptable function. Spare parts business trip When there is no appointed accurate size in the diagram, most organizations all have in general use business trip of being applicable to the size. For process size, in general use business trip's maying be a ± is 0.5 millimeters. Therefore being specified to 15.0 millimeter scopes of sizes can be of 14.5-15.5 millimeters. Other in general use business trips can be applicable to such as the angle and drill a hole with blunt bore, The casting, the forging, the welded joint and weld the angle） etc. situation. Can make reference to the diagram of past or general engineering to practice while giving the appointed business trip of a spare parts. The business trip of typical model's ising specified is martial become JSO standard define of range. Give to settle business trip to 1, for example H7/s 6, can use for being studying of spare parts size having 1 set and chart to shoulding of number. Underneath this will give concerning pack into inside bore of the concrete example with the stalk or the pillar form match.. The standard match of bore and stalk A standard of the engineering work is the business trip which makes sure a pillar form spare parts, installing for example in a tube form spare parts or bore for corresponding of. perhaps is the stalk which revolves in its inner part to match with of loose be decided by application tightly for example, a wheel gear which positions on the stalk needs to be "tight" of quiet match, here stalk of the diameter compares wheel gear actually of inside path a little bit a little bit big in order to can deliver need of Torque .Furthermore, the diameter of glide bearings has to be big in the diameter of the stalk to make it revolve. On the supposition that speak to can't become the accurate size to the parts manufacturing from the economy, all of the variety of stalk and bore size have to make sure. But, variety of scope shouldn't the too big in order to prevent assemble hour damaged For being unlikely to there is everlasting drive appointed business trip size endlessly, have already drawn up national and international standard to make sure business trip to take, for example hll/cll. For using this data, gave the definition in the traditional business trip usage. Usually what to use is the Basic hole system, because this meeting makes company internal auger needed, wring knife and pull knife and calculate the decrease of tool category. Size: Mean the number of the size numerical value by appropr