3.2 Establishment of 3D solid graphics library of headstock Figure 4 Inheritance diagram of the fork size parameter In object-oriented programming, polymorphism refers to the ability of the same message to be interpreted as a different meaning after being received by different objects. It is closely related to the inheritance of the class. An object can accept several messages of different forms and different contents. Messages of the same form can be sent to different objects. Different objects can have different interpretations of messages of the same form, and thus respond differently. In the headstock, the structural constraints are like messages. The same sub-assembly can be assembled with different or identical structural constraints and assembled into different assemblies with different sub-assemblies. For example, the II-axis sub-assembly adopts the same structural constraints (gear transmission), and the I, III-axis, and the connecting shaft are respectively assembled into different assemblies, and different structural constraints (end-alignment) are used to assemble the assembly with the cylinder assembly. The classification, polymorphism, and structural constraint diversity of each sub-assembly in the headstock are shown in Figure 5. Figure 5 Classification, polymorphism, and structural constraint diversity of each sub-assembly in the headstock 4 Conclusion In this paper, the dynamic parameters of the spindle box are calculated by Visual C ++ , and the three-dimensional solid model of the spindle box is established by using the fully correlated parallel design idea (DFA) for assembly. Its essence is to adopt the object-oriented thinking of object-oriented class, inheritance, polymorphism, dynamic binding, etc., to establish the spindle box CAD system, which greatly enhances the system's expandability and stability, so that the system can be used for future CAD. /CAM/CAE integration lays the foundation. Previous page Outdoor Light,Wall Lamp,Garden Light,Led Stair Light JINGYING , https://www.jingyinglight.com
3.2.1 Identification uniqueness, classification
- The name of the component is unique and the classification of each subassembly in the headstock assembly.
The headstock is used to contact the moving source (motor) and the actuator (spindle) of the machine. Its function is: 1 to transfer a certain amount of power from the source of motion to the executive organ. 2 to ensure the execution of a certain speed of the organ and a certain speed range. 3 It is convenient to start, stop, reverse and brake the movement as needed. According to the functional requirements, assembly relationship and design constraints of the CNC crankcase TK6410 headstock, the headstock is divided into the following major components: spindle (I-axis, actuator in the spindle) and shifting mechanism (II, III). The shaft ensures a certain speed of the organ and a certain speed regulation range. The drive train is a two-speed transmission: from the motor output shaft → the connecting shaft → the II axis → the III axis → the II axis → the I axis, thereby achieving the milling axis Required speed; from motor output shaft → connecting shaft → II axis → I axis, so as to achieve the required speed of the 镗 axis), motor output shaft type (connecting shaft is connected to the motor output shaft through the gear sleeve, used to transmit the motor power to Shifting mechanism), cylinder type (the piston in the cylinder assembly pushes the shift fork on the II and III shafts, and the shift fork makes the double-sliding external gear on the II shaft move axially and the gear on the III shaft disengages The inner gear on the right end of the meshing meshes to realize the variable speed transmission from the motor output shaft → the connecting shaft → the II axis → the I axis), and the box type (the arrangement of the axes in the box is related to the shape of the box body, and the box body is inside thereof) Supporting and sealing of each component And subjected to various load) sub-assembly and the like. These sub-assemblies are designed in parallel under the constraints of the overall assembly relationship, and each functional unit can be further decomposed into the next sub-functional unit structure. The shifting mechanism is divided into II and III shaft components, and the II and III shaft component sub-assemblies are further subdivided into shafts, bearings, and transmission members on the shaft until the structure of each functional unit is finally realized as a known shape feature or Component unit up to [3] .
3.2.2 Polymorphism, inheritance
- The interchangeability of sub-assemblies and the diversity of assembly constraints between sub-assemblies that are interchanged in parts and assemblies.
In the part, the parent feature inherits the base feature and the auxiliary feature. In the assembly, from top to bottom, the parent-child inheritance relationship between the total assembly→sub-assembly→re-sub-assembly, and the inheritance parameters inherited from the assembly constraint relationship in the upper-level assembly, such as the positioning surface The dimensional parameters and processing requirements of the mating surface, the supporting surface and the reference surface will become the design constraints of the next assembly. There are two kinds of parameters in the design process: 1 Inherit parameters from the parameters inherited from the previous layer, the design department of this layer must not only meet, but also have no right to modify directly. If the two holes of the fork are matched with the II and III axes respectively, the spacing parameters and the aperture parameters of the two holes on the fork are shown in Fig. 4. 2 The generation parameters are derived from the inherited parameters, or according to the current design needs, as shown in Figure 4, the total length of the fork, the total width size, when the inheritance parameters have changed, the relevant generation parameters should be adjusted accordingly. When the distance between the two holes on the fork and the aperture change, the total length and total width dimension also change accordingly. 
