An internal bubble reduction device for an automotive injection mold

Abstract

This utility model relates to the field of defoaming technology for injection molds, and more particularly to an internal bubble reduction device for automotive injection molds. It includes a driving device, one end of which is fixedly connected to an ejector plate. An injection mold is slidably connected to one side of the driving device, and an ejector pin is fixedly connected to one side of the ejector plate. Vent holes are provided on both sides of the injection mold. A lubrication auxiliary device is provided inside the injection mold. The lubrication auxiliary device includes a connecting pipe connected to the mold's centralized lubrication system. A lubricating oil tank is fixedly connected to the other end of the connecting pipe. A lubrication pipe is fixedly connected to the inside of the lubricating oil tank. A rotating groove is provided on the outer side of the lubrication pipe at a position inside the lubricating oil tank. An automatic lubrication structure is rotatably connected to the inner side of one end of the lubrication pipe. An elastic scraper ring is fixedly connected to the inner side of one end of the lubrication pipe. In this utility model, the ejector pin automatically triggers the rotation of the ball bearings through friction during sliding, which, combined with the oil film replenishment from the lubrication pipe, reduces the risk of dry friction between the friction pairs and ensures product quality.

Description

Technical Field

[0001] This utility model relates to the field of defoaming technology for injection molds, specifically to an internal bubble reduction device for automotive injection molds. Background Technology

[0002] An internal bubble reduction device for automotive injection molds is a specialized piece of equipment or integrated system designed to address defects such as internal bubbles and shrinkage cavities caused by residual gas during the injection molding process of automotive plastic parts. Its core objective is to reduce residual gas in the molten material by optimizing the gas discharge path, adjusting molding parameters, or actively intervening in gas flow, thereby improving the structural strength, appearance quality, and dimensional stability of the plastic parts.

[0003] The ejector pin venting structure is a key component in automotive injection molds that utilizes the tiny gap between the ejector pin and the mounting hole to achieve venting. It is driven by the hydraulic or pneumatic ejector cylinder of the injection molding machine to realize the reciprocating motion of the ejector pin.

[0004] During the long-term use of the ejector pin venting structure in automotive injection molds, the ejector pin and the mounting hole need to maintain a precise fit gap of 0.01-0.03mm to balance the needs of venting and preventing leakage. As the number of injection cycles increases, the ejector pin gradually wears down due to frequent reciprocating motion, and its diameter continues to decrease. At the same time, the mounting hole will also gradually become larger due to long-term friction from the ejector pin. During mold injection, the high-temperature and high-pressure molten material is very easy to be squeezed out from the excessive gap, resulting in material leakage and affecting product quality.

[0005] In view of this, we propose an internal bubble reduction device for automotive injection molds. Utility Model Content

[0006] The purpose of this invention is to provide an internal bubble reduction device for automotive injection molds to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] An internal bubble reduction device for an automotive injection mold includes a driving device. One end of the driving device is fixedly connected to an ejector plate, and one side of the driving device is slidably connected to an injection mold. An ejector pin is fixedly connected to one side of the ejector plate. Venting holes are provided on both sides of the injection mold. A lubrication auxiliary device is provided inside the injection mold. The lubrication auxiliary device includes a connecting pipe communicating with a centralized lubrication system of the mold. The other end of the connecting pipe is fixedly connected to a lubricating oil reservoir. A lubrication pipe is fixedly connected to the inside of the lubricating oil reservoir. A rotating groove is formed on the outer side of the lubrication pipe at a position inside the lubricating oil reservoir. An automatic lubrication structure is rotatably connected to the inner side of one end of the lubrication pipe. An elastic scraper ring is fixedly connected to the inner side of one end of the lubrication pipe. The automatic lubrication structure includes a rotating shaft. Ball bearings are fixedly connected to the outer side of the rotating shaft, and friction grooves are formed on the outer side of the ball bearings.

[0009] As a further improvement to this technical solution, the injection mold has multiple ejector friction holes and ejector cavities on its inner side. The ejector friction holes and ejector cavities are connected on their inner sides. The lubricating oil tank and lubrication pipe are located inside the ejector friction holes. One end of the ejector pin passes through the ejector friction hole and the inner side of the ejector cavity. The diameter of one end of the ejector cavity is twice the diameter of the ejector pin.

[0010] As a further improvement to this technical solution, the ejector pin includes a guide end, and a threaded hole is provided on the inner side of one end of the guide end. A threaded rod is threadedly connected to the inner side of one end of the threaded hole of the guide end, and a friction end is fixedly connected to the other end of the threaded rod.

[0011] As a further improvement to this technical solution, the inner wall of the ejector cavity has a stepped structure, and the inner wall of the injection mold at the corresponding position of the ejector cavity is provided with an auxiliary venting groove that communicates with the venting hole. The number of ejector cavities corresponds to the number of ejector pins.

[0012] As a further improvement to this technical solution, the lubrication tube is hollow, the inner diameter of the lubrication tube is adapted to the diameter of the ejector pin, the outer side of the ejector pin is slidably connected to the inner side of the lubrication tube, and the elastic scraper ring is a ring structure, with the inner side of the elastic scraper ring tightly fitted to the ejector pin.

[0013] As a further improvement to this technical solution, the balls are evenly distributed on the circumferential surface of the rotating shaft, and the two ends of the rotating shaft are rotatably connected to the inner wall of the rotating groove. The number of balls corresponds to the number of rotating grooves, and the outer side of the balls is in close contact with the inner side of the rotating groove.

[0014] As a further improvement to this technical solution, multiple friction grooves are provided. The friction grooves are semi-circular in structure and are located at the middle position on the outer side of the ball. The edge of the friction groove is in close contact with the outer side of the ejector pin.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] In this invention, the ejector pin automatically triggers the rotation of the balls through friction during sliding, converting the sliding friction between the ejector pin and the ejector pin friction hole into rolling friction. Combined with the oil film replenishment from the lubrication pipe, the risk of dry friction of the friction pair is reduced, thus extending the life of the ejector pin, ensuring product quality, and preventing ejector pin jamming caused by poor lubrication. The circumferential distribution of the balls and the semi-circular structure of the friction groove can be adapted to the irregularly shaped ejector pins commonly found in automotive molds, ensuring the lubrication of ejector pins with complex structures. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the ejector cavity structure of this utility model;

[0019] Figure 3 This is a schematic diagram of the disassembled structure of the ejector pin of this utility model;

[0020] Figure 4 This is a schematic diagram of the cross-sectional structure of the lubricating oil tank of this utility model;

[0021] Figure 5 This is a schematic diagram of the installation position of the elastic scraper ring of this utility model;

[0022] Figure 6 This is a schematic diagram of the automatic lubrication structure of this utility model.

[0023] The meanings of the labels in the diagram are as follows: 1. Drive device;

[0024] 2. Ejector plate;

[0025] 3. Ejector pin; 31. Guide end; 32. Threaded rod; 33. Friction end;

[0026] 4. Injection mold; 5. Vent hole; 6. Ejector pin friction hole;

[0027] 7. Lubrication auxiliary device; 71. Ejector pin cavity; 72. Connecting pipe; 73. Lubricating oil tank; 74. Lubrication pipe; 75. Rotating groove; 76. Automatic lubrication structure; 761. Rotating shaft; 762. Ball bearing; 763. Friction groove; 77. Elastic scraper ring. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] like Figures 1-6 As shown, this embodiment provides an internal bubble reduction device for an automotive injection mold, including a drive device 1. One end of the drive device 1 is fixedly connected to an ejector plate 2, and one side of the drive device 1 is slidably connected to an injection mold 4. One side of the ejector plate 2 is fixedly connected to an ejector pin 3. Vent holes 5 are provided on both sides of the injection mold 4. A lubrication auxiliary device 7 is provided inside the injection mold 4. The lubrication auxiliary device 7 includes a connecting pipe 72 that communicates with the centralized lubrication system of the mold. The other end of the connecting pipe 72 is fixedly connected to a lubricating oil tank 73. A lubrication pipe 74 is fixedly connected inside the lubricating oil tank 73. A rotating groove 75 is provided on the outer side of the lubricating pipe 74 at the position inside the lubricating oil tank 73. An automatic lubrication structure 76 is rotatably connected inside the rotating groove 75. An elastic scraper ring 77 is fixedly connected to the inner side of one end of the lubricating pipe 74. The automatic lubrication structure 76 includes a rotating shaft 761. A ball bearing 762 is fixedly connected to the outer side of the rotating shaft 761. A friction groove 763 is provided on the outer side of the ball bearing 762.

[0031] It should be noted that: the injection mold 4 has multiple ejector friction holes 6 and ejector cavities 71 on its inner side, the ejector friction holes 6 and ejector cavities 71 are connected on their inner sides, the lubricating oil tank 73 and the lubricating pipe 74 are set inside the ejector friction holes 6, one end of the ejector 3 passes through the ejector friction hole 6 and the inner side of the ejector cavity 71, the diameter of one end of the ejector cavity 71 is twice the diameter of the ejector 3, the ejector 3 includes a guide end 31, a threaded hole is opened on the inner side of one end of the guide end 31, a threaded rod 32 is threadedly connected to the inner side of one end of the threaded hole of the guide end 31, and a friction end 33 is fixedly connected to the other end of the threaded rod 32. The inner wall of the ejector cavity 71 has a stepped structure, and the inner wall of the injection mold 4 at the corresponding position of the ejector cavity 71 is provided with an auxiliary venting groove that communicates with the venting hole 5. The number of ejector cavities 71 corresponds to the number of ejector 3.

[0032] Further explanation: The inner diameter of the ejector cavity 71 near the friction hole is small and fits the ejector pin 3, while the inner diameter at the far end is large, forming a funnel-shaped air-gathering structure. This forces air to flow towards the auxiliary venting groove 6, effectively solving the problem of air accumulation at the root of the ejector pin 3 in deep cavity molds. The stepped ejector pin 3 and the stepped ejector cavity 71 work together to guide air to flow towards the ejector cavity 71, the auxiliary venting groove, and the venting hole 5, reducing dead zones of air stagnation and lowering the rate of air bubbles.

[0033] It should be noted that: the lubrication tube 74 is hollow, and the inner diameter of the lubrication tube 74 is matched with the diameter of the ejector pin 3. The outer side of the ejector pin 3 is slidably connected to the inner side of the lubrication tube 74. The elastic scraper ring 77 is a ring structure, and the inner side of the elastic scraper ring 77 is tightly fitted to the ejector pin 3. The balls 762 are evenly distributed on the circumference of the rotating shaft 761. The two ends of the rotating shaft 761 are rotatably connected to the inner wall of the rotating groove 75. The number of balls 762 corresponds to the number of rotating grooves 75. The outer side of the balls 762 is tightly fitted to the inner side of the rotating groove 75. Multiple friction grooves 763 are provided. The friction grooves 763 are semi-circular structures. The friction grooves 763 are located in the middle position on the outer side of the balls 762. The edge of the friction grooves 763 is tightly fitted to the outer side of the ejector pin 3.

[0034] Further explanation: The inner diameter of the hollow lubrication tube 74 is adapted to the ejector pin 3. When the ejector pin 3 slides, it squeezes the tube wall and precisely squeezes the lubricating oil into the friction contact area of ​​the ejector pin 3 where the friction is most intense. This improves the lubrication efficiency and the lubricating oil film evenly covers the surface of the ejector pin 3, so that the wear of the ejector pin 3 changes from local concentration to uniform wear over the entire area, and the life of the ejector pin 3 is extended accordingly.

[0035] Specifically: The elastic scraper ring 77 reciprocates with the ejector pin 3, scraping away plastic debris and residual lubricating oil from the surface of the ejector pin 3, preventing debris from clogging the gap of the ejector pin 3. The inner side of the scraper ring is tightly fitted to the ejector pin 3. During the injection molding and holding pressure stage, it can seal the gap between the ejector pin 3 and the ejector pin friction hole 6, preventing the molten material from leaking into the ejector pin cavity 71 due to the holding pressure. The number of balls 762 corresponds to the number of rotating grooves 75. When the ejector pin 3 slides, it drives the rotating shaft 761 to rotate through friction, without the need for an additional power source. The semi-circular friction grooves 763 on the outer side of the balls 762 scrape the surface of the ejector pin 3, reducing the ejector pin 3 jamming caused by sudden changes in the coefficient of friction.

[0036] In summary, the working principle of this solution is as follows: When the external power is connected, the drive device 1 moves the ejector plate 2 backward, and the ejector 3 is completely retracted into the ejector cavity 71, leaving a complete cavity space for injection molding. The device controls the centralized lubrication system to replenish oil to the lubricating oil tank 73 through the connecting pipe 72. The lubrication pipe 74 is filled with lubricating oil. The vent holes 5 on both sides of the injection mold 4 remain open. The auxiliary venting groove is connected to the ejector cavity 71 to form a cavity-wide venting channel.

[0037] The injection molding machine injects high-temperature molten material into the mold cavity. The molten material flows outward from the gate, squeezing the air in the cavity. The flow of molten material pushes the air to gather in the ejector friction hole 6 and ejector cavity 71. The 0.01-0.03mm gap between ejector 3 and ejector friction hole 6 becomes the key channel for air discharge. The air is discharged from the mold through ejector cavity 71, auxiliary venting groove, and venting hole 5, realizing dynamic bubble reduction through molten material propulsion, air compression, and gap venting. When ejector 3 moves forward slightly under the pressure of molten material, the friction end 33 rubs against ejector friction hole 6, triggering automatic lubrication structure 76. Rotating shaft 761 drives ball 762 to rotate in rotating groove 75. Friction groove 763 scrapes the surface of ejector 3, evenly applying the lubricating oil in lubrication tube 74 to the gap between ejector 3 and ejector friction hole 6, which reduces friction and prevents molten material from sticking due to friction.

[0038] The drive device 1 applies a holding pressure to the ejector plate 2, the ejector plate 2 moves forward slightly, and the ejector 3 forms a support for the inner wall of the plastic part to prevent the molten material from shrinking. During the holding pressure stage, the molten material still flows slightly, and the residual air continues to accumulate in the gap of the ejector 3 and the vent 5. The elastic scraper ring 77 scrapes away any molten material debris that may adhere to the surface of the ejector 3, keeps the vent gap unobstructed, and ensures that air is continuously discharged. The automatic lubrication structure 76 moves back and forth slightly with the ejector 3 to complete the last round of gap lubrication and prepare for mold opening.

[0039] The drive device 1 pulls the ejector plate 2 forward, and the ejector pin 3 extends out from the ejector cavity 71, lifting the plastic part to demold. At the moment of mold opening, the centralized lubrication system introduces lubricating oil into the lubricating oil tank 73 through the connecting pipe 72. After the ejector pin 3 is completely ejected, the elastic scraper ring 77 scrapes off the mold release agent and debris from the surface of the ejector pin 3, the lubrication pipe 74 is re-oiled, and the automatic lubrication structure 76 returns to the initial position, waiting for the next injection cycle.

[0040] During the injection filling stage, the ejector pin 3 undergoes a slight displacement due to the molten material pressure, resulting in relative movement with the ejector pin friction hole 6. The friction end 33 of the ejector pin rubs against the ejector pin friction hole 6, causing the rotating shaft 761 of the automatic lubrication structure 76 to rotate. The balls 762 on the rotating shaft 761 roll in the rotating groove 75, and the friction groove 763 scrapes against the surface of the ejector pin 3, forming frictional rotation. The centralized lubrication system continuously replenishes oil to the lubricating oil tank 73 through the connecting pipe 72, and the lubrication pipe 74 is always kept full of oil. The friction groove 763 squeezes the lubricating oil... The surface of the slide tube 74 causes the ball 762 to rotate, while simultaneously carrying lubricating oil from the inside of the lubricating oil tank 73 through the inside of the friction groove 763. The lubricating oil permeates along the 0.01-0.03mm gap between the ejector pin 3 and the ejector pin friction hole 6, forming a continuous oil film and reducing the coefficient of friction. The drive device 1 drives the ejector pin plate 2 to reset, and the ejector pin 3 retracts into the ejector pin cavity 71. Due to the return of the ejector pin 3, the automatic lubrication structure 76 rotates the shaft 761 in reverse, and the ball 762 returns to the initial position of the rotating groove 75, waiting for the next trigger.

[0041] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An internal bubble reduction device for automotive injection molds, comprising a drive device (1), characterized in that: One end of the driving device (1) is fixedly connected to the ejector plate (2), and the driving device (1) is slidably connected to the injection mold (4) on one side. The ejector plate (2) is fixedly connected to the ejector pin (3) on one side. The injection mold (4) has vent holes (5) on both sides. The injection mold (4) is provided with a lubrication auxiliary device (7) inside. The lubrication auxiliary device (7) includes a connecting pipe (72) connected to the centralized lubrication system of the mold. The other end of the connecting pipe (72) is fixedly connected to a lubricating oil tank (73). A lubricating pipe (74) is fixedly connected to the inside of the lubricating oil tank (73). A rotating groove (75) is opened on the outside of the lubricating pipe (74) at the position inside the lubricating oil tank (73). An automatic lubrication structure (76) is rotatably connected to the inside of the rotating groove (75). An elastic scraper ring (77) is fixedly connected to the inside of one end of the lubricating pipe (74). The automatic lubrication structure (76) includes a rotating shaft (761), on the outside of which a ball bearing (762) is fixedly connected, and a friction groove (763) is provided on the outside of the ball bearing (762).

2. The internal bubble reduction device for an automotive injection mold according to claim 1, characterized in that: The injection mold (4) has multiple ejector friction holes (6) and ejector cavities (71) on its inner side. The ejector friction holes (6) and ejector cavities (71) are connected on their inner sides. The lubricating oil tank (73) and lubrication pipe (74) are located inside the ejector friction holes (6). One end of the ejector (3) passes through the ejector friction holes (6) and the inner side of the ejector cavity (71). The diameter of one end of the ejector cavity (71) is twice the diameter of the ejector (3).

3. The internal bubble reduction device for an automotive injection mold according to claim 1, characterized in that: The ejector pin (3) includes a guide end (31), a threaded hole is provided on the inner side of one end of the guide end (31), a threaded rod (32) is threadedly connected to the inner side of one end of the threaded hole of the guide end (31), and a friction end (33) is fixedly connected to the other end of the threaded rod (32).

4. The internal bubble reduction device for an automotive injection mold according to claim 2, characterized in that: The inner wall of the ejector cavity (71) is a stepped structure. The inner wall of the injection mold (4) at the corresponding position of the ejector cavity (71) is provided with an auxiliary venting groove that communicates with the venting hole (5). The number of ejector cavities (71) corresponds to the number of ejector pins (3).

5. The internal bubble reduction device for an automotive injection mold according to claim 1, characterized in that: The lubrication tube (74) is hollow, and the inner diameter of the lubrication tube (74) is matched with the diameter of the ejector pin (3). The outer side of the ejector pin (3) is slidably connected to the inner side of the lubrication tube (74). The elastic scraper ring (77) is a ring structure, and the inner side of the elastic scraper ring (77) is tightly fitted to the ejector pin (3).

6. The internal bubble reduction device for an automotive injection mold according to claim 1, characterized in that: The balls (762) are evenly distributed on the circumferential surface of the rotating shaft (761). The two ends of the rotating shaft (761) are rotatably connected to the inner wall of the rotating groove (75). The number of balls (762) corresponds to the number of rotating grooves (75). The outer side of the balls (762) is in close contact with the inner side of the rotating groove (75).

7. The internal bubble reduction device for an automotive injection mold according to claim 1, characterized in that: Multiple friction grooves (763) are provided. The friction grooves (763) are semi-circular structures. The friction grooves (763) are located in the middle of the outer side of the ball (762). The edge of the friction grooves (763) is in close contact with the outer side of the ejector pin (3).

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