Local vacuum adsorption structure of double-gate ring hot-pressing die

Abstract

The present application relates to the technical field of hot forming die, in particular to a local vacuum adsorption structure of a double-ring hot-pressing die, which is applied to a hot forming die with an upper die holder, a lower die holder and a forming insert, and comprises: an exhaust passage arranged on the surface of the forming insert at a position corresponding to the edge of the double-ring door hole; and a pressure generating device in communication with the exhaust passage through a pipeline, wherein the pressure generating device has a sealed cavity. By arranging the exhaust passage on the surface of the die at a position corresponding to the edge of the door hole and connecting the exhaust passage with the pressure generating device linked with the upper die holder, the volume of the sealed cavity is increased to generate negative pressure to actively suck the gas in the die cavity when the die is closed, so as to eliminate the gas pocket defect in the edge area of the double-ring door hole, and the volume of the sealed cavity is reduced to generate positive pressure to blow gas to the die cavity when the die is opened, thereby assisting the demolding of the part.

Description

Technical Field

[0001] This invention relates to the field of thermoforming mold technology, and in particular to a local vacuum adsorption structure for a double-ring hot pressing mold. Background Technology

[0002] With the increasing demands for lightweight and safety performance in automobiles, the double door ring hot pressing forming technology is being used more and more widely in vehicle body manufacturing. The double door ring integrates the A-pillar, B-pillar, C-pillar and door sill into a single ring-shaped part, which is obtained through one hot stamping process. It has the advantages of fewer parts and higher structural rigidity.

[0003] However, the double-door ring structure, with its two openings and complex surface, presents significant technical challenges during hot pressing. When the sheet metal heated to its austenitizing temperature (approximately 930°C) is rapidly molded, air in the opening area cannot escape in time, becoming trapped between the sheet metal and the mold surface, forming an "air trap." This air trap hinders the high-temperature sheet metal from fully adhering to the mold, resulting in bulges, collapses, or unclear outlines at the edges of the openings in the molded door ring, and in severe cases, even rendering the part unusable.

[0004] In the prior art, hot press molds usually only set venting grooves at the parting surface or use the gap between ejector pins for natural venting. These passive venting methods are difficult to quickly exhaust the gas in the doorway area. The venting effect is limited by the mold gap and the distribution of ejector pins, and cannot effectively eliminate air trap defects. Summary of the Invention

[0005] In view of this, the purpose of this invention is to propose a local vacuum adsorption structure for a double-door ring hot press mold, so as to timely discharge the sealed gas in the door area during the mold closing process, ensure that the sheet material is completely attached to the mold, thereby improving the molding quality of the double-door ring.

[0006] To achieve the above objectives, the present invention provides a partial vacuum adsorption structure for a double-door ring hot-pressing mold, applicable to a thermoforming mold having an upper mold base, a lower mold base, and a forming insert. The vacuum adsorption structure includes:

[0007] An exhaust channel is provided on the surface of the shaped insert at a position corresponding to the edge of the double-ring door opening;

[0008] A pressure generating device is connected to the exhaust channel via a pipeline. The pressure generating device has a sealed chamber. The volume of the sealed chamber changes with the opening and closing movement of the upper mold base. When the mold is closed, the volume increases to generate negative pressure, and gas is drawn from the mold cavity through the exhaust channel to eliminate air trap defects. When the mold is opened, the volume decreases to generate positive pressure, and gas is injected into the mold cavity through the exhaust channel to assist in demolding the parts.

[0009] As a preferred embodiment of the present invention, the pressure generating device includes:

[0010] A piston cylinder fixedly installed on the lower mold base;

[0011] The piston is disposed inside the piston cylinder, and the piston divides the inner cavity of the piston cylinder into an upper chamber and a lower chamber. The upper chamber forms a sealed chamber, and the piston is linked to the upper mold base through the piston rod.

[0012] As a preferred embodiment of the present invention, the vacuum adsorption structure further includes:

[0013] An air cavity is fixedly installed inside the lower mold base or the lower forming insert. The exhaust channel is a plurality of exhaust holes opened on the surface of the lower mold base or the lower forming insert. The exhaust holes are connected to the air cavity. The air cavity is connected to the upper chamber of the piston cylinder through a main pipeline and a first conduit.

[0014] As a preferred embodiment of the present invention, an annular groove is provided on the circumferential surface of the piston that fits against the inner wall of the piston cylinder, and a sealing ring is fitted inside the annular groove.

[0015] As a preferred embodiment of the present invention, the air chamber is composed of multiple branches, each of which is connected to the main pipeline.

[0016] As a preferred embodiment of the present invention, the upper chamber of the piston cylinder is also connected to the mold release agent source through a second conduit. The second conduit is equipped with a one-way valve to control the one-way flow of the mold release agent into the upper chamber, so that the pressure generating device sprays gas carrying the mold release agent into the mold cavity when the mold is opened.

[0017] As a preferred embodiment of the present invention, the second conduit is further provided with a throttling valve for adjusting the amount of release agent absorbed.

[0018] As a preferred embodiment of the present invention, a mixing structure is provided in the upper chamber of the piston cylinder, the mixing structure comprising:

[0019] shrapnel;

[0020] A drive structure for driving the movement of the spring sheet, wherein the drive structure converts the vertical movement of the piston rod into rotational movement, thereby driving the spring sheet to rotate;

[0021] A stop rod is fixedly installed in the piston cylinder. The stop rod passes through a groove on the piston surface. When the spring plate touches the stop rod during rotation, it bends and accumulates elastic potential energy. When it passes the stop rod, it releases the energy to disturb the airflow in the upper chamber and promote the mixing of the release agent and the gas.

[0022] As a preferred embodiment of the present invention, the driving structure includes:

[0023] Spiral protrusions are provided on the surface of the piston rod;

[0024] The guide sleeve is fixedly installed at the upper end of the piston cylinder. The inner wall of the guide sleeve has a groove structure adapted to the spiral protrusion. The piston rod passes through the guide sleeve and the two form a spiral transmission pair through the cooperation of the spiral protrusion and the groove structure. The upper and lower ends of the piston rod are rotatably connected to the upper mold base and the piston, respectively.

[0025] As a preferred embodiment of the present invention, multiple spring plates are provided, and the multiple spring plates are evenly distributed along the circumference of the piston rod. The surface of the spring plates is provided with through holes or protrusions.

[0026] The beneficial effects of this invention are as follows: By setting an exhaust channel on the mold surface corresponding to the edge of the door opening, and connecting the exhaust channel to a pressure generating device that is linked with the upper mold base, the volume of the sealed chamber increases when the mold is closed, generating negative pressure to actively draw gas from the mold cavity, eliminating air trap defects in the edge area of ​​the double door ring door opening. When the mold is opened, the volume of the sealed chamber decreases, generating positive pressure to blow air into the mold cavity, assisting in demolding of parts, without the need for an additional ejection device or external air source. The entire pressure generating device is directly driven by the opening and closing movement of the upper mold base, without the need for an external power source and control signal, and has a simple structure. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0029] Figure 2 This is a side view of the structure of the present invention;

[0030] Figure 3 This is a three-dimensional structural diagram of the lower mold base, lower molding insert, and piston cylinder of the present invention;

[0031] Figure 4 This is a three-dimensional structural diagram of the lower molding insert and piston cylinder of the present invention;

[0032] Figure 5 This is a perspective three-dimensional structural diagram of the lower molding insert and piston cylinder of the present invention;

[0033] Figure 6 This is a schematic diagram of the bottom three-dimensional structure of the lower molding insert of the present invention;

[0034] Figure 7 This is a schematic diagram of the three-dimensional structure of the lower molding insert and air cavity of the present invention;

[0035] Figure 8 This is a schematic diagram of the piston cylinder in half section of the present invention;

[0036] Figure 9 This is a three-dimensional structural diagram of the piston cylinder, piston, spring, and stop rod of the present invention.

[0037] Figure 10 This is a partial cross-sectional three-dimensional structural diagram of the piston rod, piston, positioning sleeve, spring, rotating body, and end cap of the present invention.

[0038] The markings in the diagram are as follows: 1. Lower mold base; 2. Lower forming insert; 3. Upper mold base; 4. Upper forming insert; 5. Vent hole; 6. Air cavity; 7. Main pipeline; 8. First connector; 9. Piston cylinder; 10. Piston; 11. Annular groove; 12. Sealing ring; 13. Second connector; 14. First guide tube; 15. Piston rod; 16. Top seat; 17. Third connector; 18. Throttling valve; 19. Second guide tube; 20. Spiral protrusion; 21. Guide sleeve; 22. Rotating body; 23. Rotating groove; 24. End cap; 25. Positioning sleeve; 26. Spring; 27. Through hole; 28. Stop bar. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0040] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0041] like Figures 1 to 4As shown, the present invention provides a partial vacuum adsorption structure for a double-door ring hot press mold, applied to a thermoforming mold having an upper mold base 3, a lower mold base 1, and forming inserts. The thermoforming mold is a special mold for hot stamping of automotive double-door rings. The upper mold base 3 is mounted on the upper slide of the press, and the lower mold base 1 is fixedly mounted on the press worktable. The forming inserts include an upper forming insert 4 fixedly mounted on the upper mold base 3 and a lower forming insert 2 fixedly mounted on the lower mold base 1. These two inserts are arranged opposite each other and together stamp the heated sheet metal during mold closing.

[0042] like Figure 3 and Figure 4 As shown, as one improvement of the present invention, the local vacuum adsorption structure mainly includes an exhaust channel and a pressure generating device. The exhaust channel is located on the mold surface corresponding to the edge of the double-door ring opening, and is used to draw out the gas trapped in the mold cavity due to the closure of the door opening area when the mold is closed. The pressure generating device is connected to the exhaust channel through a pipeline. It has a sealed chamber, and the volume of the sealed chamber changes with the opening and closing movement of the upper mold base 3. When the mold is closed, the volume increases to generate negative pressure, and when the mold is opened, the volume decreases to generate positive pressure.

[0043] The pressure generating device does not require an external power source (such as a vacuum pump or compressed air source). It can achieve both vacuuming and blowing functions by relying solely on the opening and closing motion of the upper mold base 3. It has the advantages of simple structure and synchronous response.

[0044] like Figure 3 , Figure 8 and Figure 9 As shown, the pressure generating device includes a piston cylinder 9 and a piston 10 disposed within the piston cylinder 9. The piston cylinder 9 is cylindrical and fixedly installed on the outer wall of the lower mold base 1, and has a cylindrical cavity inside. The piston 10 is disposed inside the piston cylinder 9, and its outer diameter is adapted to the inner diameter of the piston cylinder 9, allowing it to slide freely along the axial direction of the piston cylinder 9. The piston 10 divides the inner cavity of the piston cylinder 9 into an upper chamber and a lower chamber, wherein the upper chamber constitutes a sealed chamber.

[0045] The piston 10 is connected to a piston rod 15. Specifically, the lower end of the piston rod 15 is fixedly or rotatably connected to the piston 10, and the upper end of the piston rod 15 extends out of the piston cylinder 9 and is fixedly or rotatably connected to the upper mold base 3. In a preferred embodiment, the upper end of the piston rod 15 is fixedly connected to the upper mold base 3 via a top seat 16, which is fixedly installed on the lower end face or side wall of the upper mold base 3. When the upper mold base 3 moves up and down with the upper slide of the press, the piston 10 is driven to reciprocate synchronously within the piston cylinder 9 via the top seat 16 and the piston rod 15, thereby causing a periodic change in the volume of the upper chamber of the piston cylinder 9.

[0046] To ensure a tight seal between piston 10 and the inner wall of piston cylinder 9, such as Figure 10As shown, an annular groove 11 is formed on the circumferential surface of the piston 10 that fits against the inner wall of the piston cylinder 9, and a sealing ring 12 is fitted inside the annular groove 11. The sealing ring 12 is preferably an O-ring, made of high-temperature resistant rubber, which can maintain good elasticity and sealing performance within the working temperature range of the thermoforming mold. When the piston 10 reciprocates within the piston cylinder 9, the sealing ring 12 fits tightly against the inner wall of the piston cylinder 9, preventing gas leakage between the upper and lower chambers and ensuring the sealing of the upper chamber.

[0047] like Figure 4 and Figure 5 As shown, the venting channels consist of multiple vent holes 5 formed on the surface of the lower molding insert 2. The diameter of the vent holes 5 is preferably 0.3mm-0.8mm. This diameter ensures smooth gas passage while preventing the softened sheet material from being sucked into the holes under negative pressure. The vent holes 5 are located on the surface of the lower molding insert 2 corresponding to the edges of the double-ring door openings, particularly at the corners and recesses of the door openings. These areas are most prone to forming air traps during mold closing due to the inability of air to escape in time.

[0048] like Figure 7 As shown, an air cavity 6 is fixedly installed inside the lower molding insert 2. The air cavity 6 is a sealed cavity located inside the lower molding insert 2 or the lower mold base 1. The lower end of the vent hole 5 penetrates the surface of the lower molding insert 2 and communicates with the air cavity 6. The air cavity 6 is connected to the upper chamber of the piston cylinder 9 through the main pipeline 7 and the first conduit 14. One end of the main pipeline 7 is connected to the air cavity 6, and the other end is provided with a first connector 8. One end of the first conduit 14 is connected to the main pipeline 7 through the first connector 8, and the other end is connected to the upper chamber of the piston cylinder 9 through a second connector 13 located on the outer wall of the upper chamber of the piston cylinder 9.

[0049] like Figure 6 and Figure 7 As shown, in a preferred embodiment, the air chamber 6 consists of multiple branches, each of which is connected to the main pipeline 7. These branches are distributed along the edge of the double-ring doorway inside the lower molded insert 2, and each branch connects to the corresponding exhaust port 5, thus ensuring that the suction path of each exhaust port 5 is independent, preventing a decrease in local exhaust efficiency due to insufficient suction at the far end. The branches can be connected to the main pipeline 7 in parallel to ensure uniform negative pressure distribution at each exhaust port 5.

[0050] like Figure 3 , Figure 8 and Figure 9As shown, to achieve the auxiliary demolding function, the upper chamber of the piston cylinder 9 is also connected to the demolding agent source through the second conduit 19. Specifically, the outer wall of the upper chamber of the piston cylinder 9 is also provided with a third connector 17. One end of the second conduit 19 is connected to the upper chamber through the third connector 17, and the other end is connected to the demolding agent source, which is a sealed container (not shown in the figure) storing liquid demolding agent.

[0051] A one-way valve (not shown in the figure) is provided on the second conduit 19. This one-way valve allows the release agent to flow unidirectionally from the release agent source into the upper chamber of the piston cylinder 9, while preventing the gas or release agent in the upper chamber from flowing back to the release agent source. When the upper mold base 3 moves downward to close the mold and the piston 10 moves downward, a negative pressure is generated in the upper chamber. The one-way valve automatically opens under the action of the negative pressure, drawing the liquid release agent from the release agent source into the upper chamber, where it is initially mixed with the drawn-in air. When the upper mold base 3 moves upward to open the mold and the piston 10 moves upward, a positive pressure is generated in the upper chamber. The one-way valve automatically closes to prevent the release agent from being forced back into the release agent source, thereby allowing the compressed gas carrying the release agent to be sprayed onto the mold surface through the first conduit 14 and the vent 5.

[0052] like Figure 5 As shown, preferably, the second conduit 19 is also equipped with a throttle valve 18 for adjusting the intake of the release agent. The throttle valve 18 can be a needle valve or a ball valve. The intake flow rate of the release agent is controlled by adjusting the valve opening to meet the needs of different types of release agents, different part shapes, and different production cycles. The lower end chamber of the piston cylinder 9 is provided with a vent hole (not shown in the figure) to balance the air pressure in the lower end chamber when the piston 10 moves up and down, thereby reducing the movement resistance of the piston 10.

[0053] like Figure 8 and Figure 9 As shown, in order to promote the full mixing of the release agent and the gas in the upper chamber of the piston cylinder 9 to form a uniform and fine aerosol mixture, a mixing structure is provided in the upper chamber of the piston cylinder 9.

[0054] The hybrid structure includes a spring 26 and a drive structure for driving the spring 26. The drive structure converts the vertical motion of the piston rod 15 into rotational motion, thereby causing the spring 26 to rotate.

[0055] Specifically, such as Figure 9 As shown, the piston rod 15 has a helical protrusion 20 on its surface. A guide sleeve 21 is fixedly installed at the upper end of the piston cylinder 9. The guide sleeve 21 is fitted over the piston rod 15, and the inner wall of the guide sleeve 21 has a groove structure that matches the helical protrusion 20. The piston rod 15 passes through the guide sleeve 21, and the piston rod 15 forms a helical transmission pair through the cooperation between the helical protrusion 20 and the groove structure on the inner wall of the guide sleeve 21. When the piston rod 15 moves up and down with the upper mold base 3, the helical protrusion 20 slides along the groove of the guide sleeve 21, forcing the piston rod 15 to rotate while moving vertically.

[0056] The upper and lower ends of the piston rod 15 are rotatably connected to the upper mold base 3 and the piston 10, respectively. For example... Figure 10 As shown, taking the connection between the upper end of the piston rod 15 and the top seat 16 as an example, the rotating structure includes a rotating body 22 and a rotating groove 23. One end of the rotating body 22 is fixedly connected to the piston rod 15, and the cross-section of the rotating body 22 is T-shaped or circular. The top seat 16 has a rotating groove 23 that fits the rotating body 22, and the rotating body 22 is embedded in the rotating groove 23 and can rotate freely. The outer end of the rotating groove 23 is threaded with an end cap 24 to prevent the rotating body 22 from falling out. The connection structure between the lower end of the piston rod 15 and the piston 10 is the same as that of the upper end, and will not be described again here.

[0057] like Figure 9 and Figure 10 As shown, a positioning sleeve 25 is fixed to the outer wall of the piston rod 15 within the upper cavity of the piston cylinder 9. The positioning sleeve 25 rotates and moves vertically together with the piston rod 15. Multiple spring plates 26 extend radially from the positioning sleeve 25 and are evenly distributed along the circumference of the piston rod 15. The spring plates 26 are elastic, thin sheet-like components, preferably made of spring steel (such as 65Mn or 50CrVA), which has good elasticity and fatigue resistance.

[0058] A stop lever 28 is fixedly mounted on the piston 10. Specifically, as shown... Figure 9 As shown, a vertically extending stop rod 28 is fixedly installed on the upper end face of the piston 10. A through groove is provided on the piston 10 for the stop rod 28 to pass through, and the upper end of the stop rod 28 extends into the upper end chamber of the piston cylinder 9. The stop rod 28 is fixedly connected to the piston 10 and moves up and down together with the piston 10.

[0059] During operation, as the piston rod 15 rotates, the positioning sleeve 25 drives multiple spring pieces 26 to rotate synchronously. When a spring piece 26 touches the stop rod 28 during rotation, the stop rod 28 remains stationary, forcing the spring piece 26 to bend and accumulate elastic potential energy. As the spring piece 26 continues to rotate and passes around the stop rod 28, it instantaneously releases its elastic potential energy, generating a rapid rebound. This disturbs the airflow in the upper chamber, promoting thorough mixing of the release agent and the gas.

[0060] Preferably, such as Figure 10 As shown, the surface of the spring 26 has through holes 27 or protrusions. The through holes 27 or protrusions can increase the contact area between the spring 26 and the airflow, generating stronger airflow disturbances during the rotation and rebound of the spring 26, and further improving the mixing effect.

[0061] Multiple spring pieces 26 are evenly distributed circumferentially, so that during each rotation, multiple spring pieces 26 collide with and rebound against the stop bar 28 in sequence, forming a continuous and periodic disturbance, ensuring that the gas-liquid mixture in the upper chamber always remains in a uniform state.

[0062] Preferably, the diameter of the exhaust hole 5 is 0.3mm-0.5mm, and it is continuously and evenly distributed along the edge of the double door ring door opening. The distance between adjacent exhaust holes 5 is 20mm-40mm.

[0063] Preferably, the throttle valve 18 is a precision needle valve, which, together with the scale knob, can precisely adjust the amount of release agent drawn in according to actual needs, so as to meet the requirements of different release agent viscosities and different spraying amounts.

[0064] Preferably, there are three spring pieces 26, which are evenly distributed at 120-degree intervals along the circumference of the piston rod 15, and each spring piece 26 has two through holes 27 on its surface.

[0065] Working principle:

[0066] When the upper mold base 3 descends with the upper slide block of the press to close the mold, the top seat 16 pushes the piston 10 downward within the piston cylinder 9 via the piston rod 15. The volume of the upper chamber of the piston cylinder 9 gradually increases, generating a negative pressure inside the chamber. Under this negative pressure, the gas in the first conduit 14, the main pipeline 7, and the air chamber 6 is extracted, and then the air in the mold cavity (between the molded surface and the sheet metal) is drawn away through the exhaust port 5, preventing air trap defects from forming at the edge of the double-door ring opening. At the same time, the one-way valve on the second conduit 19 opens under the negative pressure, drawing the liquid mold release agent from the mold release agent source into the upper chamber of the piston cylinder 9, where it is initially mixed with the extracted air. During the vertical movement of the piston rod 15, the spiral protrusion 20 engages with the groove of the guide sleeve 21, forcing the piston rod 15 to rotate. The piston rod 15 drives the positioning sleeve 25 and the spring 26 to rotate. When the spring 26 touches the stop bar 28 during rotation, it bends and stores energy. When it passes the stop bar 28, it releases energy instantly, generating airflow disturbance in the upper chamber, so that the sucked release agent and gas are fully mixed to form a uniform aerosol mixture.

[0067] The upper mold base 3 stops descending and maintains the mold closing pressure, while the piston 10 remains stationary. At this time, the upper chamber maintains a negative pressure state, continuing to maintain the suction effect within the mold cavity through the vent 5, preventing external air from entering the mold cavity. The spring piece 26 remains bent under the obstruction of the stop rod 28, storing energy for release.

[0068] When the upper mold base 3 moves upward with the upper slide of the press to open the mold, the top seat 16 pulls the piston 10 upward through the piston rod 15. The volume of the upper chamber of the piston cylinder 9 gradually decreases, the gas in the chamber is compressed, and the pressure increases. The one-way valve automatically closes under positive pressure to prevent gas or mold release agent from flowing back to the mold release agent source. The compressed aerosol mixture in the upper chamber enters the air chamber 6 through the first conduit 14 and the main pipeline 7, and is then sprayed between the mold surface and the part through the exhaust hole 5. On the one hand, the impact force of the high-pressure gas is used to "loosen" the part, and on the other hand, the mold release agent is evenly attached to the mold surface, reducing the adhesion between the part and the mold surface, and assisting the part to be demolded smoothly. During the vertical movement of the piston rod 15, the spiral protrusion 20 and the groove of the guide sleeve 21 cooperate to drive the piston rod 15 to rotate again, and the spring 26 touches and rebounds with the stop rod 28 again, continuously disturbing the aerosol mixture in the upper chamber, preventing the mold release agent from settling and stratifying during the standing process, and ensuring uniform mixing when blown out.

[0069] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity. Any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A partial vacuum adsorption structure for a double-door ring hot pressing mold, applied to a thermoforming mold having an upper mold base (3), a lower mold base (1), and a forming insert, characterized in that, The vacuum adsorption structure includes: An exhaust channel is provided on the surface of the shaped insert at a position corresponding to the edge of the double-ring door opening; A pressure generating device is connected to the exhaust channel via a pipeline. The pressure generating device has a sealed chamber. The volume of the sealed chamber changes with the opening and closing movement of the upper mold base. When the mold is closed, the volume increases to generate negative pressure, and gas is drawn from the mold cavity through the exhaust channel to eliminate air trap defects. When the mold is opened, the volume decreases to generate positive pressure, and gas is injected into the mold cavity through the exhaust channel to assist in demolding the parts.

2. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 1, characterized in that, The pressure generating device includes: Piston cylinder (9) fixedly installed on the lower mold base (1); The piston (10) is installed inside the piston cylinder (9). The piston (10) divides the inner cavity of the piston cylinder (9) into an upper chamber and a lower chamber. The upper chamber forms a sealed chamber. The piston (10) is linked to the upper mold base (3) through the piston rod (15).

3. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 2, characterized in that, The vacuum adsorption structure further includes: An air cavity (6) is fixedly installed inside the lower mold base (1) or the lower forming insert (2). The exhaust channel is a plurality of exhaust holes (5) opened on the surface of the lower mold base (1) or the lower forming insert (2). The exhaust holes (5) are connected to the air cavity (6). The air cavity (6) is connected to the upper chamber of the piston cylinder (9) through the main pipeline (7) and the first conduit (14).

4. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 2, characterized in that, The piston (10) has an annular groove (11) on its circumferential surface that fits against the inner wall of the piston cylinder (9), and a sealing ring (12) is fitted inside the annular groove (11).

5. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 3, characterized in that, The air chamber (6) is composed of multiple branches, each of which is connected to the main pipeline (7).

6. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 2, characterized in that, The upper chamber of the piston cylinder (9) is also connected to the mold release agent source through a second conduit (19). A one-way valve is provided on the second conduit (19) to control the mold release agent to flow into the upper chamber in one direction, so that the pressure generating device can spray gas carrying the mold release agent into the mold cavity when the mold is opened.

7. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 6, characterized in that, The second conduit (19) is also equipped with a throttle valve (18) for adjusting the amount of release agent drawn in.

8. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 3, characterized in that, The upper chamber of the piston cylinder (9) is provided with a mixing structure, the mixing structure comprising: Shrapnel (26); A drive structure for driving the movement of the spring (26) converts the vertical movement of the piston rod (15) into rotational movement to drive the spring (26) to rotate. A stop rod (28) is fixedly installed in the piston cylinder (9). The stop rod (28) passes through the through groove on the surface of the piston (10). When the spring piece (26) touches the stop rod (28) during rotation, it bends and accumulates elastic potential energy. When it passes the stop rod (28), it is released to disturb the airflow in the upper chamber and promote the mixing of the release agent and the gas.

9. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 8, characterized in that, The driving structure includes: Spiral protrusions (20) are provided on the surface of the piston rod (15); And a guide sleeve (21) fixedly installed on the upper end of the piston cylinder (9). The inner wall of the guide sleeve (21) is provided with a groove structure that matches the spiral protrusion (20). The piston rod (15) passes through the guide sleeve (21) and the two form a spiral transmission pair through the cooperation of the spiral protrusion (20) and the groove structure. The upper and lower ends of the piston rod (15) are rotatably connected to the upper mold base (3) and the piston (10) respectively.

10. The local vacuum adsorption structure of the double-door ring hot pressing mold according to claim 8, characterized in that, Multiple spring pieces (26) are provided, and the multiple spring pieces (26) are evenly distributed along the circumference of the piston rod (15). The surface of the spring pieces (26) is provided with through holes (27) or with protrusions.

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