Automotive Design. Car rearview mirror design(2)
2 mold structure analysis
2.3 Lateral core pulling mechanism design
For the inverted buckle 7 on the outer side of the plastic part, the mold adopts a core pulling mechanism of the inclined slider to draw the core direction. The mold preferentially designes the inclined slider on the ground side. Because of the weight of the inclined slider, the slider will fall to the ground side when the inclined guide column is core-pulled, so there is no need to design a spring. The inner side of the plastic part is inverted 1 - the reversed 4 is made of the structure of the inclined push block, the inverted buckle 5, and the inverted buckle 6 has a large area of the reverse buckle, so the structure of the combination of the oblique push block + the straight push block is adopted. The shell mold can only be manually picked up after the mold is released from the mold. The premise is that there must be space for manual picking when picking up the parts.
2.4 Temperature Control System Design
The rear view mirror housing of the automobile is an exterior part, and the appearance requirements are extremely high. One of the design principles of the cooling water channel is that the distance from the cavity surface is approximately equal to achieve a substantially uniform temperature throughout the mold cavity. The temperature control system of this mold adopts the combination of “straight-flow water pipe + inclined water channel + water well”. This combination is preferred to use straight-through water pipes, followed by inclined waterways and finally water wells. The utility model has the advantages that the plastic parts are cooled uniformly, the molding cycle is short, the molding quality is high, and the molds are suitable for high requirements and appearance performance requirements.
The layout of the automobile mold cooling channel is designed according to the following rules: 1. The direction of the cooling water should be consistent with the direction of the flow. 2. The fixed-mode cooling water channel is preferentially designed in the form of a cross grid, and the cooling circuits are formed to cross each other to form a water-way interwoven net to uniformly cool the plastic parts. 3. When it is not possible to design a cross-shaped waterway, the fixed-mode waterways are alternately arranged at a gap with each other. 4. Each group of cooling water should only design four circulating waterways as much as possible to avoid the long distance of the waterway affecting the cooling effect of the plastic parts. 5. The cooling waterway should be designed to be connected to another set of waterways for external water connection, which facilitates the adjustment of subsequent plastic parts due to deformation and shrinkage. Through the waterway to adjust the defects of plastic parts, it is widely used in automotive interior and exterior plastic parts. 6. The distance between each cooling channel is controlled by 3.5-5 times the diameter of the water channel (generally 50-60mm), and the distance from the plastic surface of the plastic part is generally between 15-25mm, depending on the size of the mold. 7. Cooling water channel and push rod. The distance between the inserts and the inserts should be 8-10mm or more. Because the mold is large and the water channel is long, it is easy to drill. 8. In the design of automobile molds, the hot nozzle should design a set of waterways as much as possible, and cannot be connected in series with other waterways to facilitate heat loss in the hot nozzle area.
The temperature control system of the fixed mold of the mold is: 4 sets of water paths are designed for the fixed molds, 2 sets of water paths are designed for each cavity, and the fixed molds are 4 in 4 out. The mold cooling waterway is designed to be in the direction of flow. Consistently, the design form of “straight-flow water pipe + inclined water channel + water well” is adopted, and the distance between the inlet and outlet water is approximately equal, so that the plastic parts have good cooling effect and appearance quality. The inclined block of the mold and the lateral projection core of the inverted buckle have a large projection area and the heat is concentrated. Therefore, the cooling water is designed on the inclined slider and the straight push block, and the glue position of the oblique slider and the direct push block is emphasized. cool down. Automotive.