A vacuum extraction device for injection moulds

Abstract

The application provides a vacuum pumping device of an injection mold, and belongs to the technical field of injection molds. The device solves the problems of low efficiency and high cost of the existing injection mold vacuum pumping device. The mold has a mold cavity, and the vacuum pumping device comprises a vacuum generator installed on the side of the mold, an air outlet channel and an installation channel located in the mold, an air inlet channel located in the mold, a one-way component and a sealing structure located in the installation channel, the sealing structure is located between the one-way component and the channel wall of the installation channel to divide the installation channel into an air outlet cavity and an air inlet cavity which are not connected with each other, the air outlet cavity and the mold cavity are separated under the action of the one-way component, the air inlet of the vacuum generator is connected with the air outlet cavity through the air outlet channel, the air outlet of the vacuum generator is connected with the air inlet cavity through the air inlet channel, and the vacuum generator drives the one-way component to move to connect the air outlet cavity with the mold cavity. The vacuum pumping device of the injection mold has the advantages of high efficiency and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molds and relates to a vacuum pumping device for an injection mold. Background Art

[0002] Injection molds are molds in which heated, molten plastic is injected into a mold cavity under high pressure by an injection molding machine. After cooling and solidification, the resulting molded product is formed. Air remains in the mold cavity, creating a tiny gap between the upper and lower molds. Traditional injection molds squeeze the air out of this gap after the molten plastic is injected into the mold cavity. However, this can result in incomplete air extrusion, reduced fluidity of the molten plastic, and the presence of bubbles in the product.

[0003] In response to the above problems, people have made various improvements, and some have even applied for patents. For example, Chinese patent literature discloses an exhaust device for automatically sucking gas from the mold cavity by vacuum [application number: 201721415499.8; authorization announcement number: CN207578986U]. Its vacuum cylinder, three-way mechanical valve, and pneumatic delay valve are fixed on the side of the mold movable mold and are connected in sequence through air pipes. The piston rod of the vacuum cylinder is fixed on the mold panel and presses the three-way mechanical valve. The electromagnetic delay top-restoring device is installed on the air channel opened at the bottom of the mold B plate and is connected to the pneumatic delay valve through the air pipe. The top block is installed in the T-slot at the bottom of the mold B plate cavity and is connected to the electromagnetic delay top-restoring device through the connecting rod in the air channel. The microswitch is fixed on the mold B plate, and the second pressing block is fixed on the mold A plate and presses the microswitch. The microswitch is electrically connected to the electromagnetic delay top-restoring device, and the electromagnetic delay top-restoring device is connected to the injection molding machine circuit.

[0004] This type of exhaust device exhausts gas from the mold cavity when the mold is closed through the coordination of multiple components. However, this type of exhaust device, which uses a vacuum cylinder, a three-way mechanical valve, a pneumatic delay valve, and an electromagnetic delay reset device, requires many components, resulting in high costs. Furthermore, the activation of these components must be sequenced, reducing exhaust efficiency. Summary of the Invention

[0005] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a vacuum pumping device for an injection mold, the technical problem to be solved is how to improve the air extraction efficiency of the vacuum pumping device.

[0006] The objectives of the present invention can be achieved through the following technical solutions: a vacuum extraction device for an injection mold, the mold having a mold cavity, the vacuum extraction device comprising a vacuum generator installed on the side of the mold, an air outlet channel and an installation channel located in the mold, characterized in that it also comprises an air inlet channel located in the mold and a one-way component and a sealing structure located in the installation channel, the sealing structure being located between the one-way component and the channel wall of the installation channel to divide the installation channel into an air outlet cavity and an air inlet cavity which are not connected to each other, the air outlet cavity and the mold cavity being separated under the action of the one-way component, the air inlet of the vacuum generator being connected to the air outlet cavity through the air outlet channel, the air outlet of the vacuum generator being connected to the air inlet cavity through the air inlet channel, and the operation of the vacuum generator drives the one-way component to move so that the air outlet cavity is connected to the mold cavity.

[0007] When the mold is closed, the vacuum generator operates, evacuating the outlet cavity through the outlet channel while simultaneously inflating the inlet cavity through the inlet channel. The gas inflated into the inlet cavity drives the one-way assembly to move, connecting the outlet cavity with the mold cavity. This allows air in the mold cavity to be drawn away through the outlet cavity and the outlet channel. The drawn-away gas then inflates the inlet cavity, which in turn propels the one-way assembly to move, thereby evacuating the mold cavity. A vacuum generator is a vacuum component that generates negative pressure using a positive pressure source. This application fully utilizes the vacuum generator's ability to inlet air on one side and outlet air on the other. Using a single vacuum generator, the one-way assembly can be moved and air in the mold cavity evacuated. The inlet and outlet processes occur almost simultaneously, improving the vacuuming efficiency of the device. Furthermore, only one component is required, resulting in low cost. The sealing structure divides the mounting channel into an outlet cavity and an inlet cavity, which are not interconnected. This prevents gas in the inlet cavity from entering the outlet cavity or the mold cavity, ensuring that the air in the mold cavity is completely evacuated.

[0008] In the above-mentioned vacuum extraction device of an injection mold, the one-way component includes an ejector rod passing through the installation channel, a first elastic member located in the air inlet cavity, and a sliding plug rod and a second elastic member located in the air outlet cavity. The ejector rod passes through the sealing structure, one end of the ejector rod is located in the air outlet cavity, and the other end is located in the air inlet cavity. Under the action of the elastic force of the first elastic member, the ejector rod always has a tendency to move away from the sliding plug rod. Under the action of the elastic force of the second elastic member, the sliding plug rod separates the air outlet cavity and the mold cavity. When the vacuum generator works, the ejector rod overcomes the elastic force of the first elastic member and the second elastic member to push the sliding plug rod to move so that the air outlet cavity is connected to the mold cavity. The first elastic member plays the role of resetting the ejector rod, so that the ejector rod no longer presses against the sliding plug rod, thereby allowing the sliding plug rod to be reset. The second elastic member plays the role of resetting the sliding plug rod, and the second elastic member separates the air outlet cavity and the mold cavity when the sliding plug rod is reset to the initial position, so that the mold cavity is not disturbed by the vacuum device during the injection molding process; the one-way is achieved through the cooperation of the ejector rod, the first elastic member, the sliding plug rod and the second elastic member, with a simple structure and low cost, and the first elastic member and the second elastic member make adaptive changes under the influence of external force, and react quickly, thereby improving the air extraction efficiency of the vacuum device.

[0009] As another case, in the above-mentioned vacuum extraction device of an injection mold, the one-way component includes an ejector rod inserted in the installation channel, a first elastic member located in the air inlet cavity and a one-way flip cover located in the air outlet cavity. The ejector rod passes through the sealing structure, one end of the ejector rod is located in the air outlet cavity, and the other end is located in the air inlet cavity. The ejector rod always has a tendency to move away from the one-way flip cover under the action of the elastic force of the first elastic member. The one-way flip cover separates the air outlet cavity and the mold cavity under the action of its own gravity or elastic force. The vacuum generator works to enable the ejector rod to overcome the elastic force of the first elastic member and push the one-way flip cover to rotate so that the air outlet cavity is connected to the mold cavity.

[0010] In the aforementioned vacuum pumping device for an injection mold, a predetermined distance exists between the plunger rod and the ejector rod in the initial state. This structure provides a certain margin to prevent the ejector rod from getting stuck on the plunger rod, ensuring that the plunger rod returns to its proper position and that the plunger rod can isolate the air outlet cavity from the mold cavity, without affecting normal injection molding in the mold cavity.

[0011] In the above-mentioned vacuum extraction device of an injection mold, the top of the air outlet cavity is fixedly connected to a cylinder, the sliding plug rod is inserted into the cylinder, the top of the cylinder has a recessed sealing groove, the top of the sliding plug rod has a sealing portion protruding outward, the outer peripheral surface of the sealing portion and the groove wall of the sealing groove are both inclined outward along the direction from the air inlet cavity to the air outlet cavity, and under the action of the elastic force of the second elastic member, the outer peripheral surface of the sealing portion is tightly fitted with the groove wall of the sealing groove to separate the air outlet cavity and the mold cavity. The outer circumferential surface of the sealing portion and the groove wall of the sealing groove are both inclined outwardly in the direction from the air inlet cavity to the air outlet cavity. Firstly, when the outer circumferential surface of the sealing portion is moved downward, it can be more tightly pressed against the groove wall of the sealing groove to achieve sealing, thereby isolating the air outlet cavity from the mold cavity. Secondly, after the sealing portion is moved upward, a gap is ensured between the outer circumferential surface of the sealing portion and the groove wall of the sealing groove, so that the mold cavity and the air outlet cavity are connected, allowing the vacuum generator to evacuate the mold cavity. The above functions are achieved by the inclined contact surface, which has a simple and ingenious structure. The gap between the outer circumferential surface of the sealing portion and the groove wall of the sealing groove does not need to be too large. As long as there is a certain gap, air can be quickly extracted to achieve vacuum. At the same time, a certain gap between the sliding plug rod and the cylinder barrel is sufficient.

[0012] In the aforementioned vacuum extraction device for an injection mold, the second elastic member is sleeved over the plunger rod and positioned within the cylinder. An adjustment bolt is removably secured to the bottom of the plunger rod. One end of the second elastic member acts on the adjustment bolt, while the other end acts on the cylinder. The second elastic member ensures that the sealing portion consistently engages within the sealing groove, isolating the air outlet cavity from the mold cavity. The adjustment bolt is rotatable and adjustable, adjusting the elastic force of the second elastic member and the distance between the plunger rod and the ejector rod, thereby ensuring that the plunger rod moves into position and seals securely.

[0013] In the aforementioned vacuum extraction device for an injection mold, a guide bolt is fixedly attached to the cylinder, and a guide groove is formed on the outer wall of the plunger rod, which is recessed along its axial direction. The inner end of the guide bolt is inserted into the guide groove, and the guide bolt moves relative to the plunger rod along the guide groove. This structure allows the plunger rod to move in a predetermined direction without rotating, thereby improving the stability of the plunger rod and, consequently, the stability of the vacuum extraction device.

[0014] In the above-mentioned vacuum pumping device for an injection mold, the sealing structure includes a cylinder body fixed in the air inlet cavity, a first sealing ring installed between the cylinder body and the wall of the air inlet cavity, and a second sealing ring installed between the ejector rod and the cylinder body. The ejector rod extends through the cylinder body into the air outlet cavity. The outer wall of the ejector rod has a protruding annular retaining edge located in the cylinder body. The first elastic member is located in the air inlet cavity and sleeved outside the ejector rod. One end of the first elastic member acts on the annular retaining edge, and the other end acts on the cylinder body. This structure prevents the air outlet cavity and the air inlet cavity from being connected to each other. The arrangement of the cylinder body can make the first sealing ring and the second sealing ring play a better sealing role. The arrangement of the annular retaining edge allows the first elastic member to abut against the ejector rod, so that the first elastic member plays a better role on the ejector rod. At the same time, the arrangement of the annular retaining edge allows the gas to better push the ejector rod to move.

[0015] In the aforementioned vacuum extraction device for an injection mold, the cylinder body has a through-hole, and the second sealing ring is located between the annular retaining edge and the cylinder body. One end of the vent is connected to the air inlet cavity between the annular retaining edge and the bottom end surface of the mounting channel, and the other end is connected to the air inlet channel. This structure allows gas generated by the vacuum generator to act on the annular retaining edge through the vent, increasing the force-bearing surface of the ejector rod and ensuring uniform force distribution on the ejector rod, thereby better promoting the movement of the ejector rod, thereby enabling the ejector rod to drive the plunger rod.

[0016] In the aforementioned vacuum evacuation device for an injection mold, the inner sidewall of the cylinder body has an annular stepped surface. After the ejector rod pushes the plunger rod a set distance, the annular stopper abuts against the stepped surface. The stepped surface acts as a limiter, preventing the plunger rod from penetrating too deeply into the mold cavity and damaging the plunger rod and the mold.

[0017] In the aforementioned vacuum extraction device for an injection mold, a sleeve is fixedly connected to the mounting channel, with a gap between the outer wall of the sleeve and the wall of the mounting channel. The ejector rod extends into the sleeve, with a gap between the outer wall of the ejector rod and the inner wall of the sleeve. Due to the presence of this gap, the sleeve does not hinder the vacuum extraction of the vacuum generator. The sleeve also protects the ejector rod, reducing the force exerted on the ejector rod during vacuum extraction, improving the stability of the ejector rod, and thus improving the stability of the vacuum extraction device.

[0018] Compared with the prior art, the vacuum pumping device for an injection mold provided by the present invention has the following advantages:

[0019] 1. This vacuum pumping device utilizes the function of the vacuum generator to take in air on one side and out on the other side. Through a vacuum generator, the one-way component can be moved to extract the air in the mold cavity. The air intake and exhaust are almost carried out simultaneously, thereby improving the exhaust efficiency of the vacuum pumping device. In addition, only one component is required, and the ejector rod, the first elastic member, the sliding plug rod and the second elastic member have a simple structure and low cost, thereby reducing the cost of the mold vacuum pumping device.

[0020] 2. This vacuum device divides the installation channel into an air outlet cavity and an air inlet cavity that are not connected to each other through a sealing structure. The components in the air outlet cavity and the air inlet cavity work independently and cooperate with each other to achieve vacuuming of the mold cavity. It has a simple structure and ingenious design. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional view of the injection mold.

[0022] Figure 2 It is a cross-sectional view of the overall structure of the vacuum pumping device of the injection mold.

[0023] Figure 3 This vacuum device Figure 1 Magnified view of area A.

[0024] Figure 4 This vacuum device Figure 1 Magnified view of area B.

[0025] In the figure, 1. mold; 2. mold cavity; 3. vacuum generator; 4. air outlet channel; 5. installation channel; 51. air outlet cavity; 52. air inlet cavity; 6. air inlet channel; 7. one-way component; 71. ejector rod; 711. annular retaining edge; 72. first elastic member; 73. sliding plug rod; 731. sealing part; 732. guide groove; 74. second elastic member; 75. adjusting bolt; 8. sealing structure; 81. cylinder body; 811. vent hole; 812. step surface; 82. first sealing ring; 83. second sealing ring; 9. cylinder barrel; 91. sealing groove; 10. guide bolt; 11. sleeve. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0027] like Figure 1 、 Figure 2 As shown, the mold 1 has a mold cavity 2 , and the vacuum extraction device of the injection mold 1 includes a vacuum generator 3 , a one-way component 7 and a sealing structure 8 .

[0028] The vacuum generator 3 is conventional and is mounted on the side of the mold 1. The outlet channel 4, inlet channel 6, and mounting channel 5 are all located within the mold 1. The outlet channel 4 and inlet channel 6 are parallel and perpendicular to the mounting channel 5. The one-way assembly 7 and sealing structure 8 are both located within the mounting channel 5.

[0029] like Figure 3 As shown, in this embodiment, the one-way component 7 includes an ejector rod 71 passing through the installation channel 5, a first elastic member 72 located in the air inlet cavity 52, and a sliding plug rod 73 and a second elastic member 74 located in the air outlet cavity 51. The ejector rod 71 passes through the sealing structure 8, one end of the ejector rod 71 is located in the air outlet cavity 51, and the other end is located in the air inlet cavity 52. ​​The ejector rod 71 always has a tendency to move away from the sliding plug rod 73 under the action of the elastic force of the first elastic member 72. The sliding plug rod 73 separates the air outlet cavity 51 and the mold cavity 2 under the action of the elastic force of the second elastic member 74. When the vacuum generator 3 works, the ejector rod 71 overcomes the elastic force of the first elastic member 72 and the second elastic member 74 to push the sliding plug rod 73 to move so that the air outlet cavity 51 is connected to the mold cavity 2. The first elastic member 72 and the second elastic member 74 74 are all cylindrical springs. In actual production, the one-way component 7 includes an ejector rod 71 passed through the installation channel 5, a first elastic member 72 located in the air inlet cavity 52 and a one-way flip cover located in the air outlet cavity 51. The ejector rod 71 passes through the sealing structure 8. One end of the ejector rod 71 is located in the air outlet cavity 51, and the other end is located in the air inlet cavity 52. ​​The ejector rod 71 always has a tendency to move away from the one-way flip cover under the action of the elastic force of the first elastic member 72. The one-way flip cover separates the air outlet cavity 51 and the mold cavity 2 under the action of its own gravity or elastic force. The vacuum generator 3 works to make the ejector rod 71 overcome the elastic force of the first elastic member 72 to push the one-way flip cover to rotate so that the air outlet cavity 51 is connected to the mold cavity 2. The first elastic member 72 and the second elastic member 74 can be conical springs or tension springs.

[0030] The top of the air outlet chamber 51 is fixedly connected to the cylinder 9. The slide rod 73 is inserted into the cylinder 9. The top of the cylinder 9 has a recessed sealing groove 91. The top of the slide rod 73 has a sealing portion 731 that protrudes outward. The outer peripheral surface of the sealing portion 731 and the groove wall of the sealing groove 91 are both inclined outward along the direction from the air inlet chamber 52 to the air outlet chamber 51. The second elastic member 74 is sleeved on the outside of the slide rod 73 and is located in the cylinder 9. The bottom of the slide rod 73 is detachably fixedly connected to the adjusting bolt 75. One end of the second elastic member 74 acts on the adjusting bolt 75, and the other end acts in the cylinder 9. Under the elastic force of the second elastic member 74, the outer peripheral surface of the sealing portion 731 and the groove wall of the sealing groove 91 are tightly fitted, thereby isolating the air outlet chamber 51 from the mold cavity 2.

[0031] A guide bolt 10 is fixedly connected to the cylinder 9 , and a guide groove 732 is provided on the outer wall of the sliding plug rod 73 , which is recessed along its own axial direction. The inner end of the guide bolt 10 is embedded in the guide groove 732 , and the guide bolt 10 moves relatively along the guide groove 732 .

[0032] like Figure 4 As shown, the sealing structure 8 is located between the ejection rod 71 and the channel wall of the installation channel 5, dividing the installation channel 5 into an air outlet cavity 51 and an air inlet cavity 52 that are not connected to each other. The air inlet of the vacuum generator 3 is connected to the air outlet cavity 51 through the air outlet channel 4, and the air outlet of the vacuum generator 3 is connected to the air inlet cavity 52 through the air inlet channel 6.

[0033] Specifically, the sealing structure 8 includes a cylinder body 81 fixed in the air inlet chamber 52, a first sealing ring 82 installed between the cylinder body 81 and the wall of the air inlet chamber 52, and a second sealing ring 83 installed between the ejector rod 71 and the cylinder body 81. The ejector rod 71 extends through the cylinder body 81 into the air outlet chamber 51. In the initial state, a predetermined distance is maintained between the slide rod 73 and the ejector rod 71. The outer wall of the ejector rod 71 includes a protruding annular retaining edge 711 located within the cylinder body 81. The second sealing ring 83 is located between the annular retaining edge 711 and the cylinder body 81. A first elastic member 72 is located in the air inlet chamber 52 and sleeved around the ejector rod 71. One end of the first elastic member 72 acts on the annular retaining edge 711, and the other end acts on the cylinder body 81. Under the elastic force of the first elastic member 72, the ejector rod 71 always tends to move away from the slide rod 73. The cylinder body 81 has a through-hole 811. One end of the vent 811 communicates with the air inlet chamber 52 between the annular retaining edge 711 and the bottom end surface of the mounting channel 5, and the other end communicates with the air inlet channel 6. The inner wall of the cylinder body 81 has an annular stepped surface 812. After the ejector rod 71 pushes the slide rod 73 a set distance, the annular retaining edge 711 abuts against the stepped surface 812.

[0034] A sleeve 11 is fixedly connected to the mounting channel 5. The bottom end of the sleeve 11 abuts against the cylinder body 81 with a gap between the sleeve 11 and the cylinder body 81. The top end of the sleeve 11 abuts against the cylinder barrel 9 with a gap between the sleeve 11 and the cylinder barrel 9. There is a gap between the outer wall of the sleeve 11 and the channel wall of the mounting channel 5. The ejector rod 71 extends into the sleeve 11, with a gap between the outer wall of the ejector rod 71 and the inner wall of the sleeve 11.

[0035] When the mold is closed, the vacuum generator 3 works, and the vacuum generator 3 evacuates the air in the sleeve 11 through the air outlet channel 4, the gap between the sleeve 11 and the installation channel 5, the gap between the sleeve 11 and the cylinder body 81, and the gap between the sleeve 11 and the cylinder 9, and inflates the air inlet cavity 52 through the air inlet channel 6 while evacuating the air outlet cavity 51. The gas filled in the air inlet cavity 52 pushes the annular baffle 711, so that the ejector rod 71 overcomes the elastic force of the first elastic member 72 and moves upward. The ejector rod 71 moves to press against the sliding plug rod 73 and overcome the elastic force of the second elastic member 74, pushing the sliding plug rod 73 to move upward, so that the outer peripheral surface of the sealing part 731 and the groove wall of the sealing groove 91 are separated, thereby continuing to evacuate the air in the mold cavity 2 through the gap between the sliding plug rod 73 and the cylinder 9, thereby realizing vacuuming of the mold cavity 2. After the mold cavity 2 is vacuumed, the vacuum generator 3 stops working. Under the elastic force of the first elastic member 72, the ejector rod 71 is reset. Under the elastic force of the second elastic member 74, the sliding plug rod 73 is reset to isolate the air outlet cavity 51 from the mold cavity 2.

[0036] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

[0037] Although this document frequently uses terms such as mold 1, mold cavity 2, vacuum generator 3, air outlet channel 4, mounting channel 5, air outlet cavity 51, air inlet cavity 52, air inlet channel 6, one-way assembly 7, ejector rod 71, annular retaining edge 711, first elastic member 72, plunger rod 73, sealing portion 731, guide groove 732, second elastic member 74, adjusting bolt 75, sealing structure 8, cylinder body 81, vent hole 811, stepped surface 812, first sealing ring 82, second sealing ring 83, cylinder barrel 9, sealing groove 91, guide bolt 10, and sleeve 11, other terms may be used. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations would be contrary to the spirit of the present invention.

Claims

1. A vacuum pumping device for an injection mold, wherein the mold (1) has a mold cavity (2), and the vacuum pumping device comprises a vacuum generator (3) installed on the side of the mold (1), an air outlet channel (4) and a mounting channel (5) located in the mold (1), characterized in that: The mold (1) further comprises an air inlet channel (6) and a one-way component (7) and a sealing structure (8) located in the mounting channel (5). The sealing structure (8) is located between the one-way component (7) and the channel wall of the mounting channel (5) to divide the mounting channel (5) into an air outlet cavity (51) and an air inlet cavity (52) that are not connected to each other. The air outlet cavity (51) and the mold cavity (2) are separated by the action of the one-way component (7). The air inlet of the vacuum generator (3) is connected to the air outlet cavity (52) through the air outlet channel (4). The air outlet of the vacuum generator (3) is connected to the air inlet cavity (52) through the air inlet channel (6). The operation of the vacuum generator (3) drives the one-way component (7) to move so that the air outlet cavity (51) is connected to the mold cavity (2). The one-way component (7) includes an ejector rod (71) passing through the installation channel (5), a first elastic member (72) located in the air inlet cavity (52), and a sliding plug rod (73) and a second elastic member (74) located in the air outlet cavity (51) or a first elastic member (72) located in the air outlet cavity (51). The one-way flip cover in the air cavity (51), the ejector rod (71) passes through the sealing structure (8), one end of the ejector rod (71) is located in the air outlet cavity (51), and the other end is located in the air inlet cavity (52), the ejector rod (71) always has a tendency to move away from the sliding plug rod (73) or the one-way flip cover under the action of the elastic force of the first elastic member (72), the sliding plug rod (73) separates the air outlet cavity (51) and the mold cavity (2) under the action of the elastic force of the second elastic member (74), and the vacuum generator (3 ) operates so that the ejector rod (71) overcomes the elastic force of the first elastic member (72) and the second elastic member (74) to push the plug rod (73) to move so that the air outlet cavity (51) is connected to the mold cavity (2), or the one-way flip cover separates the air outlet cavity (51) and the mold cavity (2) under the action of its own gravity or elastic force, and the vacuum generator (3) operates so that the ejector rod (71) overcomes the elastic force of the first elastic member (72) to push the one-way flip cover to rotate so that the air outlet cavity (51) is connected to the mold cavity (2).

2. A vacuum pumping device for an injection mold according to claim 1, characterized in that: In the initial state, there is a set distance between the sliding plug rod (73) and the ejection rod (71).

3. A vacuum pumping device for an injection mold according to claim 1 or 2, characterized in that: The top of the air outlet cavity (51) is fixedly connected to a cylinder (9), the sliding plug rod (73) is inserted into the cylinder (9), the top of the cylinder (9) has a recessed sealing groove (91), the top of the sliding plug rod (73) has a sealing portion (731) protruding outward, the outer peripheral surface of the sealing portion (731) and the groove wall of the sealing groove (91) are both inclined outward along the direction from the air inlet cavity (52) toward the air outlet cavity (51), and under the action of the elastic force of the second elastic member (74), the outer peripheral surface of the sealing portion (731) and the groove wall of the sealing groove (91) are tightly fitted to separate the air outlet cavity (51) from the mold cavity (2).

4. A vacuum pumping device for an injection mold according to claim 3, characterized in that: The second elastic member (74) is sleeved outside the sliding rod (73) and is located in the cylinder (9). The bottom of the sliding rod (73) is detachably fixed with an adjusting bolt (75). One end of the second elastic member (74) acts on the adjusting bolt (75), and the other end acts on the cylinder (9). The second elastic member (74) allows the sealing portion (731) to always have a tendency to be embedded in the sealing groove (91) so as to separate the air outlet cavity (51) and the mold cavity (2).

5. The vacuum pumping device for an injection mold according to claim 3, characterized in that: A guide bolt (10) is fixedly connected to the cylinder (9), and a guide groove (732) is provided on the outer wall of the sliding plug rod (73) and is recessed along its own axial direction. The inner end of the guide bolt (10) is embedded in the guide groove (732), and the guide bolt (10) moves relatively along the guide groove (732).

6. A vacuum pumping device for an injection mold according to claim 1 or 2, characterized in that: The sealing structure (8) comprises a cylinder body (81) fixed in the air inlet cavity (52), a first sealing ring (82) installed between the cylinder body (81) and the wall of the air inlet cavity (52), and a second sealing ring (83) installed between the ejection rod (71) and the cylinder body (81); the ejection rod (71) passes through the cylinder body (81) and extends into the air outlet cavity (51); the outer wall of the ejection rod (71) is provided with an annular retaining edge (711) protruding from the outer wall and located in the cylinder body (81); the first elastic member (72) is located in the air inlet cavity (52) and is sleeved outside the ejection rod (71); one end of the first elastic member (72) acts on the annular retaining edge (711), and the other end acts on the cylinder body (81).

7. The vacuum pumping device for an injection mold according to claim 6, characterized in that: The cylinder body (81) has a through vent hole (811), the second sealing ring (83) is located between the annular retaining edge (711) and the cylinder body (81), one end of the vent hole (811) is connected to the air inlet cavity (52) between the annular retaining edge (711) and the bottom end surface of the installation channel (5), and the other end is connected to the air inlet channel (6).

8. A vacuum pumping device for an injection mold according to claim 1 or 2, characterized in that: A sleeve (11) is fixedly connected to the installation channel (5), and a gap is formed between the outer wall of the sleeve (11) and the channel wall of the installation channel (5). The ejection rod (71) extends into the sleeve (11), and a gap is formed between the outer wall of the ejection rod (71) and the inner wall of the sleeve (11).

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