Precise injection mold for automobile plastic part

Abstract

The invention discloses an automobile plastic part precise injection mold, and relates to the field of injection molds, the automobile plastic part precise injection mold comprises a fixed mold and a lower cavity fixed at the top position of the fixed mold, and guide rods are fixed at the corners of the periphery of the fixed mold; an injection molding opening is formed in the top of the movable mold, the bottom of the injection molding opening corresponds to the upper portion of the interior of the lower cavity, the outer end of the matched air conveying pipe is connected with demolding mechanisms through a three-way valve, and the demolding mechanisms are arranged on the two sides of the interior of the lower cavity and the two sides of the interior of the upper cavity. The precise injection mold for the automobile plastic parts is provided with the sealing mechanism, the sealing mechanism is arranged, so that an attaching gasket in a sealing sleeve can slide in a frame groove, and in addition, redundant gas is conveyed into through grooves formed in an upper cavity and a lower cavity by being matched with a gas conveying pipe; at the moment, the upper cavity and the demolding mechanism in the through groove can conduct demolding work, and demolding treatment can be further conducted.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molds, and specifically relates to a precision injection mold for automotive plastic parts. Background Art

[0002] At present, with the rapid development of the automotive industry, automotive components are developing towards lightweight, integrated, and high-performance directions. Plastic parts, with advantages such as light weight, low cost, high design freedom, and simple molding process, are increasingly widely used in the fields of automotive interior and exterior parts, structural parts, and functional parts. When forming automotive plastic parts, injection molds are required for use.

[0003] There are many types of existing automotive injection molds, but there are still certain drawbacks in use. First, after the automotive plastic parts are formed, a demolding mechanism is required to process the formed plastic parts. However, adhesion is extremely likely to occur during the demolding process. To overcome the above defects, reference can be made to a demolding mechanism for automotive plastic part forming disclosed in the prior art (Chinese Patent with application number CN201920239067.9 and application date February 26, 2019). This demolding mechanism for forming is facilitated by baffles connected by rotating shafts at both ends of the top of the convex mold, which are easy to block and open. By setting a cylinder above the baffle to drive the ejector plate to eject and demold, the automotive plastic part forming mold can be efficiently ejected. The design is reasonable and the demolding efficiency is improved. By bonding a high-temperature resistant gasket at the bottom of the baffle, the sealing effect is good, the high-temperature resistant performance is good, and the structure is simple. And reference can be made to a flat injection mold for automobiles that is easy to demold disclosed in the prior art (Chinese Patent with application number CN201810755585.6 and application date July 11, 2018). This device enables the upper mold to slide on the lower mold through the set support blocks and receiving grooves, avoiding the need to remove the upper mold each time after injection, which is time-consuming and laborious. The sliding of the upper mold and the operation of the telescopic cylinder facilitate lifting and taking out the formed mold. Finally, reference can be made to an injection mold for automotive headlight production disclosed in the prior art (Chinese Patent with application number CN202110997441.3 and application date August 27, 2021). This injection mold can limit the moving direction of the upper mold base through limit posts, and the injection mold cavity is clamped inside the lower mold base through fixed lugs, which is more convenient for later removal. At the same time, the positioning frame and the inside of the lower mold base adopt a separated design, and one side can be fastened through a locking pin, enabling rapid removal of the internal structural components of the lower mold base and improving the later injection efficiency.

[0004] Although most existing mold devices use mechanical ejection methods to assist in mold release, the plastic molded parts are still in a high-temperature state during demolding. Especially after heating and injection molding with polypropylene, the initial temperature of the molded parts is between 90 and 120 degrees. When the mechanical ejection mechanism comes into contact with the surface of the high-temperature plastic part instantaneously, stress concentration is extremely likely to occur. This stress will not only leave appearance defects such as ejector pin marks and scratches on the surface of the plastic part, but may also cause internal structural damage, resulting in a decrease in the strength of the plastic part and dimensional out-of-tolerance.

[0005] Therefore, we propose a precision injection mold for automotive plastic parts to solve the problems mentioned above. Summary of the Invention

[0006] The purpose of the present invention is to provide a precision injection mold for automotive plastic parts to solve the problems in the above-mentioned background technology. That is, most of the mold devices on the current market use mechanical ejection methods to assist in mold release, but the plastic molded parts are still in a high-temperature state during demolding. When the mechanical ejection mechanism comes into contact with the surface of the high-temperature plastic part instantaneously, stress concentration is extremely likely to occur. This stress will not only leave appearance defects such as ejector pin marks and scratches on the surface of the plastic part, but may also cause internal structural damage, resulting in a decrease in the strength of the plastic part and dimensional out-of-tolerance.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A precision injection mold for automotive plastic parts includes a fixed mold and a lower cavity fixed at the top of the fixed mold. Guide rods are fixed at the four corners of the fixed mold, and the outer sides of the guide rods are slidably arranged inside the inner corners of the moving mold. An upper cavity is fixed below the moving mold. An injection port is opened at the top of the moving mold, and the bottom of the injection port corresponds to the upper part inside the lower cavity. A sealing sleeve is fixed on the outer side of the lower cavity, and the inner upper end of the sealing sleeve corresponds to the outer lower end of the upper cavity. A sealing mechanism is arranged inside the sealing sleeve. The setting of the sealing mechanism prevents gas leakage after the separation between the lower cavity and the upper cavity. The two outer ends of the sealing sleeve are also connected to one side of a matching air pipe, and the outer end of the matching air pipe is connected to a demolding mechanism through a three-way valve. The demolding mechanism is arranged on both inner sides of the lower cavity and the upper cavity.

[0008] Preferably, air inlets are communicated at both the front and rear ends of the sealing sleeve, and the outer ends of the air inlets extend into a frame groove opened inside the sealing sleeve, and a sealing mechanism is slidably arranged inside the frame groove.

[0009] Preferably, the sealing mechanism includes a fitting gasket slidably disposed at the inner position of the frame groove, and a plurality of moving tubes are fixed to the bottom position of the fitting gasket. The bottom position of the moving tube is slidably disposed inside the fixed tube, and the inner bottom position of the fixed tube is fixed to the bottom position of the return spring. The top of the return spring is fixed to the bottom position of the moving tube.

[0010] Preferably, the bottom position of the fixed tube is fixed inside the frame groove, and the fitting gasket forms a sliding structure with the inside of the frame groove through the moving tube.

[0011] Preferably, the outer side of the fitting gasket is provided with a wear-resistant layer, and an elastic airbag is also provided at the side position where the fitting gasket fits inside the frame groove. The outer side of the fitting gasket is closely attached to the outer wall of the upper cavity.

[0012] Preferably, the demolding mechanism includes a through groove communicating with the outer end of the matching air pipe, and the end of the through groove away from the matching air pipe communicates with the upper end of the vertical groove. The inner upper position of the upper end of the vertical groove is fixed to the top end of the connecting spring, and the bottom position of the connecting spring is fixed to the upper end of the top of the piston disc. A moving rod is fixed to the bottom position of the piston disc, and four fitting blocks are rotatably disposed at the bottom position of the moving rod.

[0013] Preferably, the bottom surfaces of the four fitting blocks are combined into a seamless cylinder, and the diameter of the seamless cylinder is the same as the diameter of the moving rod. The top position of the fitting block is connected to the bottom position of the moving rod through a torsion spring, and the outer side of the fitting block is slidably disposed inside the upper cavity.

[0014] Preferably, a tapered groove is formed in the inner position of the piston disc, and a tapered block is fitted inside the tapered groove. The bottom position of the tapered block is fixed to the top position of the matching spring, and the bottom position of the matching spring is fixed to the inner position of the moving rod. A cavity is formed in the inner side of the moving rod, and the bottom position of the cavity is connected to the air outlet.

[0015] Preferably, the centers of the air outlet, the tapered block, and the piston disc are collinear, and the outer side of the moving rod is slidably disposed inside the upper cavity.

[0016] Preferably, the elastic force of the matching spring is greater than the elastic force of the connecting spring, and the tapered block forms an elastic sliding structure with the inside of the tapered groove through the matching spring.

[0017] Compared with the prior art, the invention has the following beneficial effects: the precision injection mold for automobile plastic parts is provided with a sealing mechanism, and the setting of the sealing mechanism can realize the sliding of the fitting gasket inside the sealing sleeve inside the frame groove, and the gas can be conveniently injected into the upper cavity and the lower cavity by slightly lifting the upper cavity, and the molded parts inside the upper cavity and the lower cavity can be initially demolded by the principle of thermal expansion and contraction by injecting alternating hot and cold gases, and the excess gas is transported to the through grooves opened inside the upper cavity and the lower cavity through the matching gas pipe, and the demolding mechanism inside the upper cavity and the through groove can be realized to perform demolding work, and further demolding can be performed, and the specific contents are shown as follows: 1. The air inlet is provided to convey gas to the inside of the sealing sleeve, so that the fitting gasket provided inside the sealing sleeve can slide on the outside of the fixed tube through the moving tube, so that the outside of the fitting gasket can move on the outer walls of the upper cavity and the lower cavity, and the elastic airbag provided on one side of the fitting gasket is squeezed on the outer corner of the lower cavity, so as to close the gaps between the sealing sleeve, the lower cavity and the upper cavity, thereby avoiding leakage; 2. The electric push rod drives the moving mold and the upper cavity to be slightly lifted. At this time, it is necessary to ensure that the delivered gas can be delivered to the interior of the molded part. In addition, the alternating hot and cold gases delivered through the air inlet can achieve preliminary demoulding of the molded part through slight thermal expansion and contraction in the form of alternating hot and cold. Furthermore, a matching air pipe is provided. Through the gas supply work of the matching air pipe, the demoulding mechanism inside the upper cavity and the lower cavity can be operated. The movement of the moving rod can realize the expansion of the bonding block through the torsion spring. The demoulding position can be increased by opening the bonding block, and the gas outlet can be used for gas demoulding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the main structure of the present invention; Figure 2 It is a side view structural schematic diagram of the present invention; Figure 3 This is a schematic diagram of the top view of the sealing sleeve of the present invention; Figure 4 For the present invention Figure 3 The enlarged structural diagram at A in the middle; Figure 5 This is a schematic diagram of the main cross-sectional structure of the fixed tube of the present invention; Figure 6 It is a schematic diagram of the main cross-sectional structure of the upper cavity of the present invention; Figure 7 For the present invention Figure 6 The enlarged structural diagram at B in the middle; Figure 8 This is a schematic diagram of the structure of the bonding block of the present invention in an open state; Figure 9 This is the schematic diagram of the main view cross-section structure of the moving rod of the present invention.

[0019] In the figure: 1, fixed mold; 2, lower cavity; 3, guide rod; 4, moving mold; 5, upper cavity; 6, injection port; 7, air inlet; 8, sealing sleeve; 9, frame groove; 10, fitting gasket; 11, moving pipe; 12, fixed pipe; 13, return spring; 14, matching gas transmission pipe; 15, through groove; 16, vertical groove; 17, connecting spring; 18, piston disc; 19, moving rod; 20, fitting block; 21, conical block; 22, conical groove; 23, matching spring; 24, air outlet. Specific embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0021] Please refer to Figures 1-9 , the present invention provides the following technical solution: a precision injection mold for automobile plastic parts.

[0022] Embodiment 1: In order to facilitate the preliminary demolding of the plastic molded parts after molding in the lower cavity 2 and the upper cavity 5, it can be attached Figure 1 - attached Figure 5, including a fixed mold 1 and a lower cavity 2 fixed at the top position of the fixed mold 1. Guide rods 3 are fixed at the four corners of the fixed mold 1, and the outer sides of the guide rods 3 are slidably arranged inside the inner sides of the four corners of the movable mold 4. An upper cavity 5 is fixed at the lower position of the movable mold 4; an injection port 6 is opened at the top position of the movable mold 4, and the bottom position of the injection port 6 corresponds to the upper part inside the lower cavity 2. A sealing sleeve 8 is fixed at the outer side of the lower cavity 2, and the inner side of the upper end of the sealing sleeve 8 corresponds to the outer side of the lower end of the upper cavity 5. A sealing mechanism is arranged inside the sealing sleeve 8. The setting of the sealing mechanism prevents gas leakage after the separation between the lower cavity 2 and the upper cavity 5. Air inlets 7 are communicated at both the front and rear ends of the sealing sleeve 8, and the outer ends of the air inlets 7 extend into a frame groove 9 opened inside the sealing sleeve 8, and a sealing mechanism is slidably arranged inside the frame groove 9; the sealing mechanism includes a fitting gasket 10 slidably arranged at the inner side of the frame groove 9, and a plurality of groups of moving pipes 11 are fixed at the bottom position of the fitting gasket 10. The bottom positions of the moving pipes 11 are slidably arranged inside the fixed pipes 12, and the bottom position of the inner side of the fixed pipe 12 is fixed to the bottom position of a return spring 13. The top of the return spring 13 is fixed to the bottom position of the moving pipe 11; the bottom position of the fixed pipe 12 is fixed at the inner position of the frame groove 9, and the fitting gasket 10 forms a sliding structure with the inside of the frame groove 9 through the moving pipe 11; the outer side of the fitting gasket 10 is provided with a wear-resistant layer, and an elastic airbag is also arranged at the side of the fitting gasket 10 that fits inside the frame groove 9. The outer side of the fitting gasket 10 is closely attached to the outer wall of the upper cavity 5.

[0023] First, assemble the whole mold. Then, inject the heated raw material into the interior of the mold through the injection port 6. Subsequently, after cooling the whole, an automotive plastic molded part can be obtained. Then, by starting the electric push rod, the moving mold 4 can drive the upper cavity 5 to lift outside the guide rod 3, and ensure that the lifted position is small. At this time, it is only necessary to ensure that gas can be injected. At this time, the temperature of the molded part is also relatively high. At this time, inject gas into the interior of the sealing sleeve 8 through the air inlet 7. After the gas is injected, the fitting gasket 10 inside the sealing sleeve 8 can slide inside the frame groove 9. When the gas pushes the fitting gasket 10 to move, the fitting gasket 10 will also move through the moving pipe 11. Thus, the bottom position of the moving pipe 11 can slide inside the fixed pipe 12. In addition, it will also drive the return spring 13 to deform. At this time, the fitting gasket 10 will move to the outer wall position of the upper cavity 5. And when the fitting gasket 10 is moving, the elastic airbag arranged on one side of the fitting gasket 10 will also move, enabling the fitting gasket 10 to stably fit on the outer wall of the upper cavity 5. At this time, fill the gap between the upper cavity 5 and the lower cavity 2 with hot and cold alternating gas through the air inlet 7. By alternately heating and cooling the molded plastic part, due to the certain toughness of the plastic part, the plastic part can be initially demolded by the form of thermal expansion and contraction.

[0024] Embodiment 2: To solve the problem that most mold devices use mechanical ejection methods to assist in demolding, but the plastic molded part is still in a high-temperature state during demolding. When the mechanical ejection mechanism contacts the surface of the high-temperature plastic part instantaneously, stress concentration is extremely likely to occur. This stress will not only leave appearance defects such as ejector pin marks and scratches on the surface of the plastic part, but may also cause internal structural damage, resulting in a decrease in the strength of the plastic part and dimensional tolerance issues. Please refer to Attachment Figure 1 - Attachment Figure 3 and Attachment Figure 6 - Attachment Figure 9, both ends of the outer side of the sealing sleeve 8 are also connected to one side of the matching gas transmission pipe 14, and the outer end of the matching gas transmission pipe 14 is connected to the demolding mechanism through a three-way valve, and the demolding mechanism is arranged on both inner sides of the lower cavity 2 and the upper cavity 5; the demolding mechanism includes a through groove 15 connected to the outer end of the matching gas transmission pipe 14, and the end of the through groove 15 far from the matching gas transmission pipe 14 is connected to the upper end of a vertical groove 16. The inner side of the upper end of the vertical groove 16 is fixed to the top end of a connecting spring 17, and the bottom position of the connecting spring 17 is fixed to the top end of a piston disc 18. A moving rod 19 is fixed to the bottom position of the piston disc 18, and four sets of fitting blocks 20 are rotatably arranged at the bottom position of the moving rod 19; the bottom surfaces of the four sets of fitting blocks 20 combine to form a seamless cylinder, and the diameter of the seamless cylinder is the same as the diameter of the moving rod 19. The top position of the fitting block 20 is connected to the bottom position of the moving rod 19 through a torsion spring, and the outer side of the fitting block 20 is slidably arranged inside the upper cavity 5; a conical groove 22 is formed in the inner side of the piston disc 18, and a conical block 21 is fitted inside the conical groove 22. The bottom position of the conical block 21 is fixed to the top position of a matching spring 23, and the bottom position of the matching spring 23 is fixed inside the moving rod 19. A cavity is formed in the inner side of the moving rod 19, and the bottom position of the cavity is connected to an air outlet 24; the centers of the air outlet 24, the conical block 21, and the piston disc 18 are collinear, and the outer side of the moving rod 19 is slidably arranged inside the upper cavity 5; the elastic force of the matching spring 23 is greater than the elastic force of the connecting spring 17, and the conical block 21 forms an elastic sliding structure with the inside of the conical groove 22 through the matching spring 23.

[0025] When the gas fills the gap between the lower cavity 2 and the upper cavity 5, the gas will be transported through the mating gas pipeline 14. Since the upper and lower ends of the mating gas pipeline 14 are respectively connected to one side of the upper cavity 5 and the lower cavity 2, the gas can be transported into the inside of the through groove 15 through the mating gas pipeline 14. At this time, the gas will also flow into the upper end inside of the vertical groove 16. At this time, the piston disc 18 will move vertically inside the vertical groove 16, and then the return spring 13 will be deformed. When the piston disc 18 moves inside the vertical groove 16, it will also drive the moving rod 19 to move, and then the moving rod 19 can drive the fitting block 20 to move to the outside of the upper cavity 5. Since the top of the fitting block 20 is rotationally arranged at the bottom of the moving rod 19 through a torsion spring, at this time, the fitting block 20 is not limited by the groove body of the upper cavity 5, and then the fitting block 20 can rotate. At this time, after the tapered block 21 moves, the stress area of the automotive plastic part can be increased through the setting of the fitting block 20. When the tapered block 21 moves to a suitable position, it will directly act on the top of the piston disc 18, and then the tapered block 21 can move inside the tapered groove 22, and the tapered groove 22 can move in position through the mating spring 23. At this time, the gas will enter the inner cavity of the moving rod 19, and then the gas will be jetted through the air outlet 24. Then, through the jetting of the air outlet 24 and the cooperative setting of the fitting block 20, the demolding of the formed automotive plastic part can be realized again. Through the above setting, the demolding can be conveniently carried out, and the demolding efficiency can be accelerated.

[0026] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A precision injection mold for automotive plastic parts, including a fixed mold (1) and a lower cavity (2) fixed at the top of the fixed mold (1). Guide rods (3) are fixed at the four corners of the fixed mold (1), and the outer sides of the guide rods (3) are slidably arranged inside the four corners of the movable mold (4). An upper cavity (5) is fixed below the movable mold (4). It is characterized in that: An injection port (6) is opened at the top of the movable mold (4), and the bottom of the injection port (6) corresponds to the upper part inside the lower cavity (2). A sealing sleeve (8) is fixed on the outer side of the lower cavity (2), and the inner upper end of the sealing sleeve (8) corresponds to the outer lower end of the upper cavity (5). A sealing mechanism is arranged inside the sealing sleeve (8). The setting of the sealing mechanism prevents gas leakage after the separation between the lower cavity (2) and the upper cavity (5). The two outer ends of the sealing sleeve (8) are also connected to one side of a matching air pipe (14), and the outer end of the matching air pipe (14) is connected to a demolding mechanism through a three-way valve. The demolding mechanism is arranged on both inner sides of the lower cavity (2) and the upper cavity (5).

2. The precision injection mold for automotive plastic parts according to claim 1, wherein: Air inlets (7) are connected to both the front and rear ends of the sealing sleeve (8), and the outer ends of the air inlets (7) extend into a frame groove (9) opened inside the sealing sleeve (8). A sealing mechanism is slidably arranged inside the frame groove (9).

3. The precision injection mold for automotive plastic parts according to claim 2, wherein: The sealing mechanism includes a fitting gasket (10) slidably arranged inside the frame groove (9). A number of moving pipes (11) are fixed at the bottom of the fitting gasket (10). The bottom of the moving pipes (11) is slidably arranged inside fixed pipes (12). The inner bottom of the fixed pipes (12) is fixed to the bottom of a return spring (13), and the top of the return spring (13) is fixed to the bottom of the moving pipes (11).

4. The precision injection mold for automotive plastic parts according to claim 3, characterized in that: The bottom of the fixed pipes (12) is fixed inside the frame groove (9), and the fitting gasket (10) forms a sliding structure with the inside of the frame groove (9) through the moving pipes (11).

5. The precision injection mold for automotive plastic parts according to claim 3, wherein: The outer side of the fitting gasket (10) is provided with a wear-resistant layer, and an elastic airbag is also arranged on one side of the fitting gasket (10) that fits inside the frame groove (9). The outer side of the fitting gasket (10) is closely attached to the outer wall of the upper cavity (5).

6. The precision injection mold for automotive plastic parts according to claim 1, wherein: The demolding mechanism includes a through groove (15) connected to the outer end of the matching air pipe (14). The end of the through groove (15) away from the matching air pipe (14) is connected to the upper end of a vertical groove (16). The top end of a connecting spring (17) is fixed to the inner upper side of the upper end of the vertical groove (16), and the bottom of the connecting spring (17) is fixed to the upper top of a piston disk (18). A moving rod (19) is fixed to the bottom of the piston disk (18). Four fitting blocks (20) are rotatably arranged at the bottom of the moving rod (19).

7. The precision injection mold for automotive plastic parts according to claim 6, wherein: The bottom surfaces of the four groups of the fitting blocks (20) are combined into a seamless cylinder, and the diameter of the seamless cylinder is set to be the same as the diameter of the moving rod (19). The top position of the fitting block (20) is connected to the bottom position of the moving rod (19) through a torsion spring. The outer side of the fitting block (20) is slidably arranged inside the upper cavity (5).

8. The precision injection mold for automotive plastic parts according to claim 6, characterized in that: A tapered groove (22) is formed in the inner side position of the piston disc (18), and a tapered block (21) is fitted inside the tapered groove (22). The bottom position of the tapered block (21) is fixed to the top position of the cooperation spring (23). The bottom position of the cooperation spring (23) is fixed inside the moving rod (19). A cavity is formed in the inner side of the moving rod (19), and the bottom position of the cavity is connected to the air outlet (24).

9. The precision injection mold for automotive plastic parts according to claim 8, characterized in that: The centers of the air outlet (24), the tapered block (21), and the piston disc (18) are collinear. The outer side position of the moving rod (19) is slidably arranged inside the upper cavity (5).

10. A precision injection mold for automotive plastic parts according to claim 8, characterized in that: The elastic force of the cooperation spring (23) is greater than the elastic force of the connection spring (17), and the tapered block (21) and the inner part of the tapered groove (22) constitute an elastic sliding structure through the cooperation spring (23).

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