Foreword is based on a tie build a model to build product model easily not only, and facilitate the model makes pair of CAD revise and be operated. And build modular method to compare before, the associated sex that be based on the built up fixture of the tie to assemble the advantage of the method that build a model is a lot of problems in including clamping apparatus to design; Once defined a tie, special in the process that modifying a design, should change other condition to be able to maintain only assemble a relation. 1, of clamping apparatus can model built up fixture is by the standards of an all sorts of different appearance that had made beforehand, different measurement, standard unit that has interchangeability or component, restrain what the relation is combined and become according to certain assembly. According to this definition, can express built up fixture to be: G = {Vi, r (Vi of ∈ of Ri of Ri ︱ , vj) , in the type on} of Vi ∈ , v expresses the gather of component of built up fixture, vi represents component of built up fixture or component; R expresses the restrains a relation gather between component or component, ri represents element or a kind of tie between package concerns. A kind of meshy concern was formed between such component and component, among them meshy node for component (package) , the connection between node relies on their assembly to restrain a relation. Assemble a structure to be able to show with two kinds of means a certain assemble a design: One is logistic structure, one is graphical structure. The spare parts that logistic structure conveyed composition to assemble a model, child the administrative levels between the component concerns, just like the tree of catalog structure. The logistic hierarchy that assembles a model adopts a plan the assembly of 1 cultivates expression. Graphical structure is a certain geometry that assembles a model expresses, use intuitionisticly decompose chart to show. Root component: Root component is automatic when generating a new assembly drawing generation, be assemble most top layer. Child component: Assemble a medium logistic team, form by the spare parts child assemble, child the component is OK nest random deepness. Spare parts: The lowest in hierarchy one class, it is single entity, cannot tear open less substance. Graph 1 clamping apparatus assembles the ultimate goal that upholds clamping apparatus design is the function that should realize clamping apparatus. The functional definition that the functional model of clamping apparatus is pair of clamping apparatus and functional behavior have description and expression, it is substaintial to clamping apparatus definition. Set out from the structure of clamping apparatus can define each component (package) the functional dependency between, make the information about status of way of clamping apparatus function, work, job is contained in clamping apparatus model. Functional model is clamping apparatus model be clamping apparatus hierarchy is taller the abstraction of one class. So called function builds this system the model designs a requirement to have a description to clamping apparatus namely, have the integral function of clamping apparatus decomposing refining, correspondence of every stature function component of a function (package) , build the functional structure tree of a clamping apparatus. The functional cell that uses in this system and functional relation will describe the functional structure of clamping apparatus, among them functional concern states the action between functional component concerns. The functional model of clamping apparatus is the has hierarchy function tree that makes by component of clamping apparatus function and functional relation; Cultivate an overall function that expresses clamping apparatus, the leaf nods those who express clamping apparatus function to decompose, namely child function. Have between master node that is to say decompose, accede and concern abstractly, father function is child functional purpose, child the method that the function is father function and implementation, be father function is incorporate. With the relation that parallel connection also is had between administrative levels node or establishs ties, its interaction is interdependent, the goal with be finished stated jointly as the method (father function) , compose concerns into functional paralell connection; If press some kind of ordinal and ordinal action, form functional series connection to concern. 2, three-dimensional structure assembles technology and principle to assemble a relation is to build clamping apparatus spare parts, part or the key that immanent tie concerns between component, component. The assembly of clamping apparatus concerns is the fixed position relation between component commonly, go out through defining the positional relation between component to be able to be described whole the dimensional position of the component in assembling system and coordinate a relation. What UG founds is parameter is changed assemble, can bring to bear on for many times on a spare parts tie, bring to bear on to restrain even if reduce a spare parts to freedom is spent or move to the spare parts type, limit the opposite movement between the spare parts, the position of the spare parts in and adopt the associated fixed position of dot, edge, axis or face assembling a model certainly and cooperate means. UG is OK and wraparound give 3 kinds of following basic assembly: Top-down is assembled, bottom-up is assembled, mix assemble; 8 kinds of conjugate restrain: Joint (Ma2te) , alignment (Align) , angle (Angle) , parallel (Parallel) , orthogonality (Perpendicular) , right in (Center) , distance (Distance) , tangent (Tangent) . Those who be worth to point out is, afore-mentioned 8 kinds in cooperating basically to restrain, with " joint " most common. (The basic idea that bottom-up assembles 1) is: The design independence of the component of certain assembly parts is assembled at the on one class of this assembly parts besides, namely preexistence is designed independently in this class, join with appearance of on one stage again. After join, the assembly parts that specific spare parts is joined will be updated automatically, reflect all changes that make in place of spare parts phase. The spare parts of any three-dimensional scale can have other part to add it above, accordingly, any component become assembly parts possibly. Can develop a few to be added with Yu Tian tall the sub assembly parts of one class assembly parts, this tall one class assembly parts also can be used as likewise taller the sub fittings of one class fittings, the relation pursues as follows between assembly parts and sub assembly parts 2 are shown, namely A of one class assembly parts is comprised by 3 main parts, the A of sub assembly parts of B of 2 class assembly parts can be formed again after assembly parts A is finished, also but a component of B of regard as assembly parts. Manage together, assembly parts B forms the B of sub assembly parts of C of 3 class assembly parts again, the rest may be deduced by analogy, bottom-up undertakes constructional. Among them main part may be a spare parts also may be assembly parts. Graph 2 bottom-up classification the process of a kind of design that uses normally in the CAD software that assembling bottom-up to design a process is a tradition. Its main idea is to had designed each parts first, build a spare parts to the geometric constraint between concerns and match into luggage next, if discover in rigging a process certain part does not accord with a requirement, such as: Spare parts of interference, some arises to cannot undertake installing waiting at all between spare parts and spare parts, be about to undertake redesigning to the spare parts, assemble afresh, rediscover problem, undertake modification waiting again. Design process because beforehand the program with very good neither one, the consideration of neither one overall situation, the serious go back to work of design phase is made a lot of, created the waste of time and manpower resource, work efficiency is low. Graph 3 top-down assemble means one (top-down assembles 2) have two kinds of kind, if the principle pursues 3 found the assembly parts that exclusive also is the superlative degree above all namely, found its among them component again, make a tie to this component next. Notable is the law is assembled in top-down in, the tie includes the join tie with other component and the simple obligation to this component feature. Top-down assembles way way 2 principles pursue as follows: Graph 4 top-down assemble means 2 produce assembly parts first namely, amid does good place to want geometric constraint system for its component, add place to need to restrain to the middle of the component again when producing new part. In most time, the basis is designed and restrain need, two kinds of means often mix use. To the tie, when use join is restrained, it is OK to mean the person that use the component that root establish designs arrives the different component of assembly parts. (3) supports top-down / the form of collateral outfit prescription of bottom-up. This decides by two respects: ① by fictitious assemble a system to build modular method to decide; ② should distinguish the assembly at traditional built up fixture. Traditional built up fixture basically is a worker install those who deserve to rise by experience and skill handiwork, because this has very big optional sex. Worker different, experience different, setting the mood is different, different metropolis influence fabricates a result; And a lot of knowledge are to pass a worker to fumble gradually, accumulate those who get, and do not save easily. Planar 2 dimension blueprint is only comfortable Yu Jian's odd assembly, and unwell Yu Fu is miscellaneous assemble. The assembly to improve clamping apparatus quality, the assembly that raises clamping apparatus efficiency, our will collateral thought and top-down / the designed a method to introduce built up fixture assembly that bottom-up photograph combines establishs modular procedure. Top-down / the design method that bottom-up photograph combines is integrated consideration habit of engineering personnel thinking and the process of a kind of design that rig model detail compose to build. Generally speaking, be comprised by a few component only the built up fixture with complex function is impossible, and sure be assemble system. Because this is correct, the built up fixture that accords with thinking habit assembles body to design a process should be the effective demand according to workpiece assemble a model roughly what define built up fixture (support oneself and fall) , the appearance of each component mixes the built up fixture that affirmatory need chooses between them coordinate a relation, the detailed alternative that norms of component of each built up fixture develops below the tie that assembling a model next (go up from the bottom) , at the same time rougher to be being defined formerly built up fixture assembles a model to give refine or revise, the course supports a few times oneself and fall, the built up fixture that the iteration of bottom-up can get according with a requirement is fictitious assemble body to design. 3, in be based on the assembly of the tie to build a model to be designed in most built up fixture, a built up fixture often is the combination of component of many clamping apparatus, assemble system namely. Alleged assembling system is to point to by a series of disperse child the has specific function mechanical part that the component is combined by relation of a certain position and becomes. The key that assembles body implementation is assemble system interior what the position between each stature component affects is affirmatory. We can undertake translation through two pairs component, rotate wait for geometry to alternate the command will come true, the parameter computation that the system inputs according to the user gives commutation matrix, also can input directly of course child the commutation matrix of the component will come true. Assemble build a model to have two kinds of methods, namely bottom-up builds model and top-down to build a model. Former it is to be after integral plan is definite, design personnel uses CAD tool to undertake the detailed structure of each spare partses is designed respectively, define the assembly between these spare partses to concern next, form product model. Latter builds the function of the product to amount to above all, analyse this kind of expression to whether satisfy product requirement, use CAD system to refine the geometrical structure of the spare parts ceaselessly when the architect next, in order to make sure the structure of the spare parts satisfies the functional requirement of the product, build product model. What built up fixture builds a model to use these two kinds of means is integrated. Because design of actual built up fixture is not strict bottom-up design, go up in whole however bottom-up, be in local the working way that goes up to still be put in top-down. At the same time requirement of clamping apparatus function and plan design are restricting the structure of clamping apparatus component to design, and the outfit recipe record that the detailed structure design of clamping apparatus component is affecting clamping apparatus again conversely, the process that relapses the process that clamping apparatus designs is clamping apparatus function and plan design and detailed design of structure of clamping apparatus component actually each other, because this component builds model and clamping apparatus,assemble build a model to need union to undertake. The assembly of clamping apparatus the model is to build what go up in base of high-level semantics information, consequently clamping apparatus assembles a model to need to use a feature to build a model. Built up fixture by inferior yuan of subassembly and into, the component is mixed by more inferior component again child component composition. System of CAD of built up fixture uses constructional tie to concern to assemble these component and part built up fixture according to certain arrangement of ideas. The whole of built up fixture assembles modelling to take the working kind of bottom-up, its rig a process general component is two paces: The first pace is to build assemble a tree. Will build assemble yuan of component of tie concern to be added in assembling a tree. The 2nd pace is yuan of component gives to add a tie in assembling a tree, with drop off yuan the presses a regulation tie that the freedom of the component is spent and makes is assembled rise form built up fixture. The tie is a kind of concern that must satisfy between specific element, in formally it can express to be synthesized for one atom, set C to be symbol of N dimension predication, use at representing the sort of the tie, Σ is market of controlled controlled element (wait like dot, line, face) , it is symbolic expression, use at expressing the attribute of a certain tie, so a tie but described as: (C E E2... En - 1 V) among them C ∈ C, Σ of Ej ∈ , v ∈ V passes what design a process to assembling system actually to make an on-the-spot investigation, can sum up give the following kinds of common assembly body restrains a condition, these ties basically consider from geometrical respect, the to seeming a part geometry develop that restrains effect consequently attacks element. These positional ties can divide from engineering design angle for the following 5 kinds: (1) face cooperates (Mate) and equidistant cooperate (Mate Offset) : The face cooperates to ask two surfaces that assemble body part are contacted each other, namely double law vector is contrary, of the face equidistant cooperate to ask two surfaces Xiang Xiangping goes and apart a certain distance. Cooperate (Mate) can handle a variety of tie positions. Chooses geometrical form depends on what use cooperate to restrain a type. Optional object and answer realizable to assemble include: Planar -- planar / planar, planar / axes; Axes -- axes / axes, planar / axes, axes / dot; Dot -- dot / dot, dot / axes; Be not flat surface (spherical, conic, columnar, or cirque) . If define the outline surface of axes,cannot choose: Define hypostatic and sectional tangent surface; Be not the surface that defines spherical, taper seat, cylinder and cirque. (2) is right neat (Align) and equidistant right neat (Offset) : Right neat it is to show the coincide between two objects concerns, it can be divided again to face neat, the side is right neat, those who nod department of local to be being reached together coordinate is right neat. Face neat it is to point to two surfaces coincide and direction is consistent. Of the edge right neat it is to show two edges coincide is in same and linear go up, the place is right neat it is to show two nod coincide, of local coordinate right neat it is to show two local coordinate fasten complete coincide, equidistant right neat it is to show two faces are parallel and apart a certain distance. (3) inserts (Insert) : Describe aperture and axis coordinate a relation, ask namely the axes coincide of the axes of aperture and axis. (4) is coaxial (Coaxis) : Between descriptive axis and axis coordinate a relation, requirement the axes coincide of two axes. (5) is directional (Orient) : Requirement two plane two two parallel, with equidistant right neat different is it do not need to appoint the distance between two faces. The assembly of system of CAD of built up fixture restrains cent to be the following kinds: Cooperate, to neat, alignment angle is mixed insert, the tie between face and dot, line and their implementation face and face, face and line, line, line and dot and dot and dot. The face can be planar also can be columnar face, the line can be linear, axes and vector direction, the dot can be hypostatic acme, end points and the centre of a circle. Through the tie (the freedom that Constraints) eliminates work is spent undertake constructional. If the example that is based on a tie to assemble pursues 5, among them A graph is axial workpiece, b graph is the built up fixture of mill keyway. Graph the 5 example that are based on a tie to assemble 1. Rectangular foundation board 2.
Directional key 3.
Workpiece 4.
V form piece bearing 5.
Stretchy pressing plate 6.
Close solid bolt 7.
The hex nut that take a shoulder 8.
Bedspring 9.
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