【正文】 Is intermittent motion needed? (10) Styling． Does the color have eye appeal? Is the sharp desirable? Is the machine well proportioned? Are the calibrations on dials easily read? Are the controls easy to operate? (11) Drawings． Are standardized parts used? Are the tolerances realistic? Is the surface finish overspecified? Must the design conform to any standards? (12) Ergonomics． Has the operator of the equipment been considered? Are the controls conveniently located to avoid operator fatigue? Are knobs， grab bars， hand wheels， levers， and dial calibrations of proper size to fit the average operator? 1． 4 A general procedure of machinery design Whatever design tasks the designers are expected to plete， they always， consciously or unconsciously， follow the similar process which goes as follows： (1)Studies of feasibility After understanding the product functions， operational conditions， manufacturing constraints and key technologies， go on to uncover existing solutions to some similar problems so as to clarify the design tasks， understand the needs， present the major functional parameters and evaluate design tasks， proposal of design aims， and feasibility analysis． (2) Conceptual design of configuration According to the design of tasks and functional parameter， designs need to extensively search for various feasible configurations and alternatives． For convenience， usually， the system can be analyzed prehensively by deposing it into power sources， transmission and work mechanisms． A great effort needs to be devoted to the analysis and synthesis of these different parts． For example， the power source may be selected from motor， engine and turbine． Each power source may have a range of power and kinematical parameters ． Similarly, power trains may have numerous options available， e． g． belts， chains， gears， worm gears and many other drives． Obviously selecting an appropriate configuration would guarantee the Success of the whole design and the quality of the products． To make a best possible decision， an iterative process is normally required to select， analyze， pare and evaluate different configurations． At this stage， the goals involve sketching of configuration， determination of kinematical mechanisms， and evaluation of functional parameter(power and kinematics)． (3)Detailed technical design Based on the design of configuration and parameters， a number of assembly and ponent drawings will be pleted to reflect the detailed design including kinematics， power， strength， stiffness， dynamics， stability， fatigue and SO on． Consideration should also be given to manufacturing factors by presenting structural details， materials， and both geometric and dimensional tolerances． This part of work will also be carried out in a repeated process in drawings， calculation， evaluation and modification 中英文資料 6 until a best possible design is achieved． The goal at this stage is to plete assembly and ponent drawings， structural details， design calculations and detailed technical documentations． (4)Modification of design After the design is pleted， a prototype is usually made for a more realistic physical assessment of the design quality． This will help correct any drawback or fault that may be overlooked or neglected during the design process． At this stage， the goal is to correct the design imperfection， test the potential manufacturing or assembly flaws and refine /improve design． 1． 5 Contents and tasks of the course The course Machinery Design will cover the following contents： (1)Preliminaries． the fundamental principles of machinery and Components design， design theory， selection of materials， structure， friction ， wear and lubrication． (2)Connection． sand． joints． thread． fasteners， keys， rivets， welds， bonds ． and adhesive and interference joints． (3)Transmission． screws， chains， belts， gears， worms， bevel． gears And helical gears． (4)Shaft． system． rolling—contact． bearings， sliding bearings， clutches， couplings， shafts， axles and spindles． (5)Other part s． springs， housings and frame s． The course centers on engineering design of mechanical ponents and is in a category of fundamental methodology and procedure． It is not feasible or realistic for the students to bee involved in the detailed design considerations associa