First: Wang Jianling, female, born in 1962, associate professor, Department of Mechanical Engineering, Tangshan College, Tangshan, Hebei (063000), Tel: 0315 - Automotive gearbox rear body is an extremely important shifting component and safety component of the car, requiring a good comprehensive Mechanical properties, deformation and fatigue failure should not occur during the shifting process, using die casting.
1 part of the process analysis of the car gearbox rear body see material for ADC12 Japanese brand TCH5302 and China's material YL118 performance is similar. The material has the advantages of light weight, good heat exchange performance and low cost. The overall size of the parts is large, about 175mmx305mm less, the mass is 45kg, the partial wall thickness is 4mm, and the average wall thickness is 6mm. The shape of the part is complex, the cavity depth is 305mm, the two ends are small and small, and the side has one hole. The rest consists of 4 steps and rib structures. The die casting requires high mechanical properties, and requires no cold insulation, slag inclusion, pattern, crack and other defects. After the whole part is die-casted, except for the threaded hole, other parts need not be machined or sandblasted in principle.
2 mold structure design 21 part of the surface selection as shown, because the part cavity depth of 305mm, if the parting surface is selected in AA, the height of the core is large, the deep cavity is not conducive to molding, the exhaust is difficult, easy to produce insufficient pouring Defects such as pores, and the difficulty of selecting die casting equipment. Finally, the B~B surface was selected as the parting surface, which not only avoids the difficulties in the molding process brought by the deep cavity, but also is very convenient in selecting the die casting machine.
22 clamping force calculation 221 back pressure F inverse calculation cm2 (where SA is the projected area of the die casting on the parting surface, SA is poured into the projection area of the gate on the parting surface, SA is the residual material The projected area on the parting surface, SA overflow is the projected area of the overflow groove on the parting surface); p is the injection specific pressure, the wall thickness of the MPa die casting is 3~6mm, when the structure is more complicated, the specific pressure is 60~70MPa here take 63MPa1. 222 acts on the core pulling mechanism. The normal core is calculated. The main core adopts the hydraulic core pulling mechanism a as the wedge angle of the locking block, a is 13°.
Since the core is stepped, the length is 15mm at a diameter of 225mm; the length at a diameter of 200mm is 82mm; the length at a diameter of 142mm is 100mm. The core pulling force of each diameter is 1650N, 1500N, 1100N. Side core The upper core of the hydraulic core pulling mechanism adopts the oblique guide column lateral core 24 lateral split core design. Since the parting surface of the mold is B~B surface, the core perpendicular to the parting surface has a main core, The upper core and the side core are seen. The molten metal fills the cavity during die casting. After the condensation shrinks, the clamping force is generated on the forming part of the movable core. When the core is pulled, the tightening force generated by the shrinkage of the die casting and the movement of the core pulling mechanism are overcome. When the various resistances, the two are the core pulling force. At the moment of starting the core pulling, the required core pulling force is the largest, which is the starting core pulling force. When the core pulling is continued, it is only necessary to overcome the resistance of the mechanism and the core movement, and the successive core pulling force is referred to here. The core force is the initial core pulling force.
The mass of the main core, the side core and the upper core are respectively 197mm, 47mm, 60mm. The main core and the side core have large extraction force, and the main core is opened by the die casting machine. The ejector mechanism is ejected, and the side core is powered by a hydraulic cylinder for lateral core pulling. When the upper core is opened and closed by the mold, the oblique guide column and the slider are laterally divided for core pulling. After calculation, the diameter of the inclined guide column is 45. The length of the inclined guide column is 202 mm and the inclination angle is 20°. The upper core (see) is large and small, and it is difficult to integrate with the main core, and the main core has a parting surface.
3 The mold structure and working process are shown as the mold assembly drawing. Mould action process: mold-opening using frame structure to develop low-pressure casting control system Liu Yanping Yang Bo Zhang Hu Xu Huibin (Beijing University of Aeronautics and Astronautics) Structural development industrial process control system can not only reduce the difficulty of early development and post-maintenance costs, but also develop computer control system Stable performance, reliable operation and easy maintenance.
Modern industrial control systems not only have to directly control the production process and production equipment, but also to achieve information management of the entire production process, but it also increases the complexity of the entire system and the difficulty of development.
This topic introduces a framework design method suitable for the development of industrial control systems, and uses this structure to develop the BH-1 series low pressure casting control system. Practice has proved that the industrial control system developed on the basis of this frame structure can realize the effective management of complex systems, reduce the development difficulty, and has the advantages of high reliability, flexible configuration and easy maintenance.
1 frame structure design method The so-called frame structure means that when designing the system, the system framework is designed according to the functions to be realized by the system, and then the system is divided into relatively independent modules according to functions and filled into the designed frame. Go in. Each module contains software and hardware that implements certain functions, and is self-contained, and communication between modules and modules is performed in a way that the framework has been designed.
The system architecture idea of the framework structure is closely related to the modular idea. It consists of two elements: 1 decompose a complex system into its own distinct, relatively independent components called module decomposition; 2 interconnect these separate parts through standardized and compatible interfaces (or interfaces) For a complete system, it is called a module set. The framework structure is the result of module decomposition. If the system architecture is based on a framework structure at the beginning of development, the workload and difficulty of later development and maintenance (ie, module aggregation) will be greatly reduced.
2EH-1 low pressure casting control system frame structure and working process 21BH-1 low pressure casting control system working process BH-1 low pressure casting control system is divided into 5 subsystems: 1 pressure control subsystem; 2 mold temperature controller System; 3 furnace heating control subsystem; 4 machine motion control subsystem; 5 casting expert system subsystem. The pressure control subsystem accurately realizes the pressure control of the furnace according to the set pressure curve; the mold temperature control subsystem controls the switch of each cooling passage according to the parameter setting of the 20-way cooling passage; the furnace heating control subsystem enables the holding furnace The temperature of the inner aluminum liquid is stable at the pouring temperature; first: Liu Yanping, male, born in 1981, master's degree, School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing (at the time of the die casting machine, the moving mold seat plate 1 is moved backwards) Due to the connection of the bolts 2, the spacer 5 supports the plate splitter 8 and the movable die plate 7 and the movable die insert 13 are moved back along the guide post 16, while the slider 46 moves along the guide groove of the movable die plate. The transverse core pulling of the upper core is realized by the oblique pin 47. When the mold is opened to the upper core, the slider 46 is restricted by the limiting block 40. The casting and the pouring system continue to move with the moving mold, and at the same time When the main core 19 and the side core 21 are moved to the maximum opening distance, the core is started under the action of the hydraulic cylinder, and the hydraulic cylinder corresponding to the mold opening direction on the die casting machine is applied to the push rod, and the push rod is placed on the push rod. The mold is ejected from the board and ejected from the board.
When the mold is closed, the movable mold moves to the fixed mold, and the reset rod contacts the parting surface, so that the reset rod drives the ejector mechanism to reset the ejector rod, and at the same time, the upper core is reset along the guide chute under the action of the inclined guide column, the main The core and the side core are reset by the action of the hydraulic cylinder.
4 Conclusion The mold structure used in this design is verified by production, the structure is reasonable, the action is reliable, and it meets the requirements of die casting process. The lateral parting and core pulling action is smooth, the filling and exhausting are good, and the shape, dimensional accuracy, surface quality, compactness and mechanical properties of the die-casting parts meet the drawing requirements.
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