1、Mechanical design theory The mechanical design is a application technical science through design the new product or improves the old product to meet the human need. It involves all domain of the project technology, mainly research size of the product , basic idea of the shape and the detailed struct
2、ure, also research question of manufacture , sale and use of the product in all aspects. They usually called designer or mechanical design engineer who carries on each kind of mechanical design work. The mechanical design is a creative work. Design engineer not only have the creativity in the work,
3、but also have the deep elementary knowledge on mechanical drawing, kinematics, engineering material, materials mechanics and machine manufacture technology. As says above, the goal of mechanical design is the production can meet the human need. The invention, the discovery and technical knowledge it
4、self certainly not necessarily can bring the advantage to the humanity, only when they are applied on the product can produce the benefit. Thus, we should realize whether people do need this kind of product before carry on the design in a specific product. The mechanical design must regard as a good
5、 opportunity for the mechanical designer to use creative ability carries on product design, the systematic analysis and formulate manufacture technology of the product. Grasping the project elementary knowledge is more important than memorizing some data and the formula. Merely using the data and th
6、e formula is insufficient to completely decide all decision in a good design. On the other hand, they should carry on all operations precisely. For example, even if place a decimal point in wrong position, also can turn the correct design to wrong. New designs can have many flaws and problems unexpe
7、cted, only these flaws and the question have been solved, can new products superiority be manifested. Therefore, a superior product born followed a higher risk at the same time. What should emphasize is that if designs itself does not request to use the brand-new method, it is not necessary to use t
8、he new method merely for the goal for transformation. In the preliminary stage of design, should allow designer fully to display the creativity, not restraint to each kind of restraint. Even if have many impractical ideas in early time, they can also be corrected before plan blueprint. Only in this
9、way can not stop the innovation. Usually, must propose several sets of design proposals, and then perform the comparison. It is possible that some ideas have been used in the final plan which is not accepted before. The psychologist frequently discusses the causes of how could people adapt to machin
10、e which operate. A designers personnels basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because the most superior operating area and the operating process to all do not exist in fact. Another important question, project engineer must be
11、able to carry on the exchange the consultation with other concerned personnel. In the initial stage, designer has to exchange with administrator on the preliminary design, and be approved. This is generally through the oral discussion, with schematic diagram and the writing material. In order to car
12、ry on the effective exchange, needs to solve the following problem: (1) Whether product designed is truly needed for the people? (2) Whether this product has competitive ability compare with other companys existing similar products? (3) Whether this kind of product is economical? (4) Whether this pr
13、oducts service convenient? (5) Whether this product sale well? Whether can gain? Only time be able to produce the correct answer to above question. But, the product design, the manufacture and the sale only can continue on foundation of the above question preliminary answered. Project engineer also
14、should consult together with the branch of manufacture for the finally design proposal through the detail drawing and the assembly drawing. Usually, can have some problem in the manufacture process. Possibly can request to some components size or the common difference makes some changes, causes the
15、components the production to change easily. But, in the project change must have to pass through designs the personnel to authorize, guaranteed cannot damage the product the function. Sometimes, when in front of product assembly or in the packing foreign shipment experiment only then discovers in th
16、e design some kind of flaw. These instances exactly showed the design is a dynamic process. Always has a better method to complete the design work, designs the personnel to be supposed unceasingly diligently, and seeks this better method. Recent year, the engineering material choice already appeared
17、 importantly. In addition, the choice process should be to the material continuously the unceasing again appraisal process. The new material unceasingly appears, but some original materials can obtain the quantity possibly can reduce. The environmental pollution, material recycling aspect and so on
18、use, workers health and security frequently can attach the new limiting condition to the choice of material. In order to reduce the weight or saves the energy, possibly can request the use different material. Comes from domestic and international competition, to product service maintenance convenien
19、ce request enhancement and customers aspect the and so on feedback pressure, can urge the people to carry on to the material reappraises. Because the material does not select when created the product responsibility lawsuit, has already had the profound influence. In addition, the material and betwee
20、n the material processing interdependence is already known by the people clearly. Therefore, in order to can and guarantees the quality in the reasonable cost under the premise to obtain satisfaction the result, project engineer makes engineers all to have earnestly carefully to choose, the determin
21、ation and the use material. Makes any product the first step of work all is designs. Designs usually may divide into several explicit stages: (a) preliminary design； (b) functional design； (c) production design. In the preliminary design stage, the designer emphatically considered the product should have function. Usually must conceive and consider several plans, then decided this kind of thought is whether feasible； If is feasible, then should makes the further improvement to or several plans. In this stage, the question
