Plate type servo vacuum valve

Abstract

The present application relates to the technical field of mechanical valve, and discloses a plate type servo vacuum valve, which comprises an upper valve body, a lower valve body, a valve block seat and an execution structure. The upper valve body is provided with a containing groove connected with a die exhaust port. The lower valve body is integrated with a signal channel and a pumping channel. The execution structure adopts a signal core, a transmission rod and a valve core split parallel double-shaft layout. The valve core is provided with a pressure maintaining core and a ventilation core. The constant pressure gas source is used to realize automatic reversing opening and closing of pneumatic force by using the area difference of the valve core boss. A reset rod and a cold mold gas piston are further arranged to realize mechanical pre-pressing and pneumatic forced valve closing respectively. The present application offsets the metal liquid impact and the valve core movement direction, reduces the valve core wear, has compact valve body structure and small space occupation, realizes stable opening and closing by relying on air pressure self-maintenance, realizes bistable state, and is suitable for vacuum exhaust of pressure casting die.

Description

Technical Field

[0001] This invention relates to the field of mechanical valve technology, specifically to a plate-type servo vacuum valve, which is particularly suitable for vacuum exhaust systems of die-casting molds. Background Technology

[0002] During the die-casting process of metal parts, air inside the mold cavity can lead to poor filling and ultimately cause porosity in the die-cast parts after processing. To avoid porosity in die-cast products, a common method is to add venting at the end of the mold filling process—using a vacuum pump to extract air from the mold, while simultaneously using a vacuum valve placed between the mold and the vacuum pump to prevent molten metal from entering the vacuum tank of the vacuum pump.

[0003] Existing vacuum valves can be classified into the following categories according to their structure, and the following problems exist during their use:

[0004] 1. Coaxial impact type: The direction of the molten metal entering the vacuum valve is in the same straight line as the axial direction of the valve core. When the molten metal just enters, the valve core is subjected to a large instantaneous impact force, which can easily accelerate the wear of the valve core and reduce its service life. Moreover, the coaxial impact type requires a core pulling mechanism for demolding, which is complex in structure, large in size, not conducive to the arrangement of complex molds, and occupies a long installation space.

[0005] 2. Vertical offset type (no active retraction): The direction of the molten metal impact is perpendicular to the valve core axis. Although the impact wear is reduced, the valve core reset and closing still rely on the elastic reset of the disc spring. There is no active air pressure drive, the closing speed is slow, the reliability is poor, and it is easy to misoperate. It cannot withstand excessive vibration. Summary of the Invention

[0006] This invention provides a plate-type servo vacuum valve, which aims to solve the problems in related technologies, such as severe wear of the valve core caused by the molten metal impact direction being collinear with the valve core axis, the mechanical valve occupying a long installation space, and the slow closing response of existing mechanical valves.

[0007] The plate-type servo vacuum valve of the present invention includes an upper valve body having a receiving groove capable of communicating with the exhaust port of a die-casting mold, and further includes:

[0008] The lower valve body is fastened to the upper valve body. The lower valve body has a signal channel, a suction channel communicating with the receiving groove, a vent communicating with the suction channel, and a suction port communicating with the vent. The suction port is used to communicate with the suction end of an external vacuum pump.

[0009] Starting an external vacuum pump allows for sequential evacuation of the mold cavity through the extraction port, vent, extraction channel, and receiving tank.

[0010] A valve block seat is installed on the lower valve body, and the valve block seat has a mating cavity and a valve core movable hole;

[0011] The execution structure includes a signal core slidably disposed within the signal channel, a transmission rod hinged to the valve block seat, a valve core portion slidably disposed on the valve core movable hole, and an elastic reset mechanism mounted on the mating cavity. The central axis of the signal core is coplanar and parallel to the central axis of the valve core portion. The signal core contacts the upper side of the transmission rod, one end of the transmission rod is engaged with the valve core portion, and the lower side of the transmission rod abuts against the movable end of the elastic reset mechanism.

[0012] The valve core portion has a pressure-holding core and a venting core connected to the pressure-holding core. The venting core has a blocking part and a venting part. The venting part is connected to the receiving groove and the air extraction channel. The valve core portion can be moved down to make the blocking part close the air extraction channel.

[0013] Preferably, the valve core movable hole has an upper hole and a lower hole communicating with the upper hole, and the pressure holding core has a first core, a boss connected to the first core, and a second core connected to the boss, with the second core slidably connected in the lower hole.

[0014] Preferably, the cross-sectional area of ​​the boss portion is larger than the cross-sectional area of ​​the second core portion, and the cross-sectional area of ​​the second core portion is larger than the cross-sectional area of ​​the first core portion;

[0015] The valve block seat also has a constant pressure vent hole that communicates with the valve core movable hole, and the constant pressure vent hole is connected to an external constant pressure air source.

[0016] The valve core portion also has a guide block, which is interference-sealed on the inner wall of the upper hole. The guide block has a clearance hole in the middle for the first core portion to pass through, and a main sealing ring is provided at the bottom of the guide block. The guide block is sealed to the edge of the boss portion through the main sealing ring.

[0017] Preferably, the first core has a first transmission hole and a insertion hole, the vent core is inserted into the insertion hole of the first core, the vent core has a second transmission hole, and the transmission rod passes through the first transmission hole and is inserted into the second transmission hole.

[0018] Preferably, the lower valve body includes a lower valve block, which has a signal sleeve hole, a suction sleeve hole, a suction port communicating with the suction sleeve hole, and a limiting hole communicating with the signal sleeve hole. The diameter of the signal sleeve hole is smaller than the diameter of the limiting hole. A signal bushing is interference-fitted into the signal sleeve hole. The signal channel is located inside the signal bushing. The top of the signal channel is connected to the receiving groove, and the bottom of the signal channel is communicating with the limiting hole. A suction bushing is interference-fitted into the suction sleeve hole. The suction channel and the vent are both located on the suction bushing.

[0019] Preferably, the signal core has an upper sliding portion and a lower sliding portion connected to the upper sliding portion. The diameter of the lower sliding portion is larger than the diameter of the upper sliding portion. The upper sliding portion is slidably disposed in the signal channel, and the lower sliding portion is slidably connected in the limiting hole.

[0020] Preferably, a sealing groove is formed on the outer periphery of the signal core, and a heat-resistant sealing ring is embedded in the sealing groove. The outer periphery of the heat-resistant sealing ring slides and seals against the inner wall of the signal channel.

[0021] Preferably, the bottom of the signal core is provided with a top block, and one end of the transmission rod is hinged to the valve block seat through a rotating shaft.

[0022] Preferably, the elastic reset mechanism includes a top plate slidably connected in the mating cavity, the top of the top plate abutting against the lower side of the transmission rod, and a disc spring fixedly installed at the bottom of the top plate, the bottom of the disc spring abutting against the bottom of the mating cavity, the elastic force of the disc spring being able to drive the top plate to move upward.

[0023] Preferably, it also includes two reset rods and two cold mold gas pistons, all of which are slidably mounted on the lower valve body. The reset rods can be pressed down and moved when the mold is closed. The bottom of the reset rods contacts the top of the top plate. The lower valve body has a plug hole adapted to the cold mold gas piston. The plug hole is connected to an external air source through an air passage. The cold mold gas piston is located above the transmission rod.

[0024] The beneficial effects of this invention are:

[0025] By adopting a vertical parallel dual-axis layout for the signal core and valve core, the impact direction of the molten metal is offset perpendicularly from the valve core axis, avoiding direct impact of the liquid flow on the valve core, significantly reducing the instantaneous impact force on the valve core, reducing valve core wear, and significantly extending the valve core service life.

[0026] The vertically staggered signal triggering and valve core closing structure eliminates the need for a long-stroke valve core along the direction of molten metal flow, effectively shortening the axial dimension of the valve body, reducing installation space, and adapting to the compact layout requirements of die-casting molds.

[0027] The system utilizes an elastic reset mechanism in conjunction with a transmission rod to achieve the linkage between the signal core and the valve core for opening and closing. It relies on the difference in cross-section of the pressure-holding core boss and an external constant pressure air source to form a self-balancing air pressure, enabling automatic valve reversal and normal air pressure locking to prevent malfunctions. The system features fast opening and closing response, stable structure, reliable switching between vacuuming and pressure holding shutdown, and prevents molten metal from flowing back into the vacuum pump. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a specific embodiment of the present invention.

[0029] Figure 2This is a cross-sectional schematic diagram of the lower valve body in a specific embodiment of the present invention.

[0030] Figure 3 This is a cross-sectional schematic diagram of the lower valve body and valve block seat in a specific embodiment of the present invention.

[0031] Figure 4 It is in this invention Figure 3 Enlarged structural diagram at point A in the middle.

[0032] Figure 5 This is a cross-sectional schematic diagram of the lower valve body and valve block seat in a specific embodiment of the present invention.

[0033] Figure 6 This is a cross-sectional schematic diagram of the pressure-holding core and the ventilation core in a specific embodiment of the present invention.

[0034] Figure 7 It is in this invention Figure 6 Enlarged structural diagram at point B.

[0035] Figure 8 This is a schematic diagram of the structure of the ventilation core in a specific embodiment of the present invention.

[0036] Figure 9 This is a schematic diagram of the transmission rod, valve core, and elastic reset mechanism in a specific embodiment of the present invention.

[0037] Figure 10 This is a cross-sectional schematic diagram of the reset rod and the cold mold gas piston in a specific embodiment of the present invention.

[0038] Figure 11 This is a schematic diagram of the reset rod and cold mold gas piston in a specific embodiment of the present invention.

[0039] Figure label:

[0040] 10. Upper valve body; 11. Receiving groove; 20. Lower valve body; 21. Lower valve block; 211. Signal sleeve hole; 212. Suction sleeve hole; 213. Suction port; 214. Restriction hole; 22. Signal bushing; 221. Signal channel; 23. Suction bushing; 231. Suction channel; 232. Vent; 30. Valve block seat; 31. Mating cavity; 32. Valve core moving hole; 321. Upper hole; 322. Lower hole; 3221. Vent; 33. Constant pressure vent; 40. Actuating structure; 41. Signal core; 411. Upper sliding part ; 412, Lower sliding part; 413, Top block; 42, Transmission rod; 43, Valve core part; 431, Pressure holding core; 4311, First core part; 43111, First transmission hole; 4312, Boss part; 4313, Second core part; 432, Vent core; 4321, Sealing part; 4322, Vent part; 4323, Second transmission hole; 4324, O-ring; 433, Guide block; 4331, Main sealing ring; 44, Elastic reset mechanism; 441, Top plate; 442, Disc spring; 50, Reset rod; 60, Cold mold gas piston. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the present invention, and not all of the embodiments.

[0042] like Figures 1 to 11 The diagram shows an embodiment of the plate-type servo vacuum valve of the present invention, mainly comprising an upper valve body 10, which has a receiving groove 11 that can communicate with the exhaust port at the filling end of the die-casting mold. A lower valve body 20 is fastened to the upper valve body 10, forming a cavity for containing molten metal together with the receiving groove 11 of the upper valve body 10. The lower valve body 20 has a signal channel 221, an air extraction channel 231 communicating with the receiving groove 11, and an air extraction channel 231 communicating with the air extraction channel 231. The ventilation port 232 and the extraction port 213 connected to the ventilation port 232 are connected to the extraction end of the external vacuum pump. The external vacuum pump can evacuate the cavity of the die-casting mold through the extraction port 213, the ventilation port 232, the extraction channel 231 and the receiving groove 11. The valve block seat 30 is fixedly connected to the lower valve body 20. The actuator 40 is installed on the valve block seat 30 and the lower valve body 20 and can stably open or close the extraction channel 231.

[0043] refer to Figures 1 to 5As shown, the lower valve body 20 includes a lower valve block 21, which can be engaged with the upper valve body 10. It should be noted that the top surface of the lower valve block 21 can form a cavity with the receiving groove 11 on the upper valve body 10. This cavity is used to accommodate molten metal entering the plate-type servo vacuum valve. Specifically, the lower valve block 21 has a signal sleeve hole 211, a suction sleeve hole 212, a suction port 213 communicating with the suction sleeve hole 212, and a limiting hole 214 connected to the signal sleeve hole 211. The diameter of the signal sleeve hole 211 is smaller than the diameter of the limiting hole 214. The suction port 213 is mainly used to connect to an external vacuum pump. A signal bushing 22 is interference-fitted into the signal sleeve hole 211 to maintain a sealed fit between the signal bushing 22 and the lower valve block 21. The signal bushing 22 is tubular and has a signal channel 221 inside. The top of the signal channel 221 is connected to the receiving groove 11. The bottom of 221 is connected to the limiting hole 214. An air extraction bushing 23 is interference-fitted into the air extraction sleeve hole 212 to maintain a sealed fit between the air extraction bushing 23 and the lower valve block 21. The air extraction bushing 23 is tubular and has an air extraction channel 231 connected to the receiving groove 11 and an air vent 232 connected to the air extraction channel 231. The air vent 232 is aligned with and connected to the air extraction port 213, so that the air extraction port 213, the air vent 232, the air extraction channel 231 and the receiving groove 11 form a connecting air passage. When the external vacuum pump is started, it can evacuate the cavity of the mold through the connecting air passage.

[0044] refer to Figure 1 , Figure 3 , Figure 5 and Figure 6 As shown, the valve block seat 30 is fixedly spliced ​​on the lower valve block 21. The valve block seat 30 has a mating cavity 31, a valve core movable hole 32, and a constant pressure vent hole 33 communicating with the valve core movable hole 32. The valve core movable hole 32 is coaxially arranged with the air extraction channel 231. The valve core movable hole 32 has an upper hole portion 321 and a lower hole portion 322 communicating with the upper hole portion 321. The bottom of the lower hole portion 322 also has a vent hole 3221 that penetrates the valve block seat 30. The constant pressure vent hole 33 is used to communicate with an external constant pressure air source. The constant pressure air source is provided by external compressed air to inject constant air pressure into the valve core movable hole 32.

[0045] refer to Figures 3 to 9 As shown, the execution structure 40 includes a signal core 41 slidably connected in the signal channel 221, a transmission rod 42 hinged to the valve block seat 30, a valve core portion 43 installed in the valve core movable hole 32, and an elastic reset mechanism 44 installed in the mating cavity 31.

[0046] It should be noted that the central axis of the signal core 41 is coplanar and parallel to the central axis of the valve core portion 43. The signal core 41 has an upper sliding portion 411 and a lower sliding portion 412 connected to the upper sliding portion 411. The diameter of the lower sliding portion 412 is larger than the diameter of the upper sliding portion 411. The upper sliding portion 411 is slidably connected in the signal channel 221, and the top surface of the upper sliding portion 411 extends to the bottom of the receiving groove 11, so that the molten metal entering the receiving groove 11 can impact the upper sliding portion 411 to push the upper sliding portion 411 into the signal channel 221. The lower sliding portion 412 is slidably connected in the limiting hole 214 to limit the upward movement of the signal core 41, prevent the signal core 41 from moving too far upward and detaching from the signal channel 221, and improve precision. The signal core 41 is also provided with a sealing groove around its periphery, and a high-temperature resistant sealing ring is embedded in the sealing groove. In this embodiment, the high-temperature resistant sealing ring is a high-temperature fluororubber sealing ring. The outer periphery of the high-temperature resistant sealing ring slides and seals against the inner wall of the signal channel 221 to ensure the circumferential sealing between the signal core 41 and the signal channel 221, and can isolate the release agent and metal slag from contaminating the valve body. The bottom of the signal core 41 also has a support block 413, which can receive the transmission power of the transmission rod 42. One end of the transmission rod 42 is hinged to the valve block seat 30 through a rotating shaft, and the other end of the transmission rod 42 is engaged with the valve core part 43. Moreover, under the elastic action of the elastic reset mechanism 44, the transmission rod 42 abuts against the support block 413 to push the signal core 41 to move upward. Conversely, the downward movement of the signal core 41 can be achieved by the support block 413 pressing down on the transmission rod 42. The deflection of the transmission rod 42 can move the valve core part 43 downward. In this way, the transmission rod 42 converts the linear displacement of the signal core 41 into a pushing force on the valve core part 43, realizing cross-axis transmission of motion.

[0047] The valve core part 43 includes a pressure-holding core 431, a venting core 432, and a guide block 433. The pressure-holding core 431 has a first core part 4311, a boss part 4312 connected to the first core part 4311, and a second core part 4313 connected to the boss part 4312. The first core part 4311 has a first transmission hole 43111 and a insertion hole. One end of the transmission rod 42 passes through the first transmission hole 43111. The second core part 4313 is slidably connected in the lower hole part 322. It should be noted that the cross-sectional area of ​​the boss part 4312 is larger than the cross-sectional area of ​​the second core part 4313, and the cross-sectional area of ​​the second core part 4313 is larger than the cross-sectional area of ​​the first core part 4311, so that the upper area of ​​the boss part 4312 is larger than the lower area of ​​the boss part 4312. A venting core 432 is inserted into the insertion hole of the first core 4311. A second transmission hole 4323 is provided on the venting core 4322. The transmission rod 42 passes through the first transmission hole 43111 and is inserted into the second transmission hole 4323. The deflection of the transmission rod 42 can move the pressure holding core 431 and the venting core 432 through the transmission of the first transmission hole 43111 and the second transmission hole 4323. The venting core 432 is slidably connected in the suction channel 231 of the suction bushing 23. It should be noted that the pressure holding core 431, the venting core 432, the guide block 433 and the valve core movable hole 32 form a servo cylinder structure. The guide block 433 acts as a cylinder structure and the venting core 432 acts as a piston structure. An O-ring 4324 is provided on the outer circular surface of the venting core 432. The O-ring 4324 forms a gas pressure seal with the inner wall of the suction channel 231, which can also isolate the release agent and aluminum slag from contaminating the inside of the valve body. The venting core 432 has a sealing part 4321 and a venting part 4322. Both the venting part 4322 and the venting part 4322 are connected to the receiving groove 11 and the suction channel 231. The sealing part 4321 can be moved downwards to be placed inside the suction channel 231 and seal it. A sealing ring is engaged with the outer ring of the second core 4313. This sealing ring moves with the second core 4313, abutting against and sliding relative to the inner wall of the lower hole 322 of the valve core movable hole 32, ensuring circumferential sealing, maintaining pressure balance, and preventing metal-to-metal friction. It should be noted that the gas at the bottom of the second core 4313 and inside the lower hole 322 can flow through the venting hole 3221, communicating with external air pressure.

[0048] In addition, the guide block 433 is interference-fitted onto the upper hole 321, and the guide block 433 and the upper hole 321 are directly sealed. It should be noted that the guide block 433 has a clearance hole in the middle, and the first core 4311 passes through the clearance hole of the guide block 433. Moreover, there is a gap between the outer wall of the first core 4311 and the inner wall of the clearance hole of the guide block 433 to allow gas flow. The bottom of the guide block 433 is engaged with the main sealing ring 4331 through a slot. The main sealing ring 4331 is sealed and fitted to the edge of the boss 4312, so that the boss 4312 and the guide block 433 are circumferentially sealed through the main sealing ring 4331. The main sealing ring 4331 is mainly used to seal the gap between the guide block 433 and the pressure holding core 431 to prevent gas leakage.

[0049] The elastic reset mechanism 44 includes a top plate 441 slidably connected in the mating cavity 31. A sealing ring is snapped around the periphery of the top plate 441. The sealing ring can seal the circumference to prevent foreign objects from entering the mating cavity 31 and reduce contamination of the mating cavity 31. A disc spring 442 is installed at the bottom of the top plate 441. The spring force of the disc spring 442 is upward. When the mold is opened, the spring force of the disc spring 442 can drive the top plate 441 to move upward, thereby pushing the transmission rod 42 to move. The movement of the transmission rod 42 drives the signal core 41 to move upward, pushing the signal core 41 and the metal residue solidified in the channel out together, and at the same time pushing the valve core part 43 to the upper end face of the cylinder bore.

[0050] It needs to be explained that the external constant pressure gas can enter the valve core moving hole 32 through the constant pressure vent 33. Since the boss part 4312 is sealed with the guide block 433 through the main sealing ring 4331, the connection between the valve core moving hole 32 and the first core part 4311 is cut off. Since the O-ring 4324 forms a gas pressure seal with the inner wall of the air extraction channel 231, the communication between the molten metal side and the gas pressure side is isolated. When the plate servo vacuum valve is in the open state, since the pressure-bearing area of ​​the boss part 4312 is larger than other parts, a gas pressure area difference is formed. The constant pressure gas acts on the effective pressure-bearing surface on the lower side of the boss part 4312, pushing the boss part 4312 to continuously press the guide block 433 upward, so that the gas pressure drives the valve core part 43 to tend to the upper valve body 10, so that the sealing part 4321 on the vent core 432 is in the upper position, generating a stable upward holding force. The venting section 4322 remains connected to the receiving tank 11 and the evacuation channel 231. The vacuum pump can evacuate the mold cavity through the evacuation port 213, the venting port 232 on the evacuation bushing 23, the evacuation channel 231 on the evacuation bushing 23, the venting section 4322, and the receiving tank 11 to prevent the airflow from moving the venting core 432, thus maintaining the stability of the venting core 432. When the molten metal enters the receiving tank 11, some of the molten metal can impact the signal core 41, causing the signal core 41 to move and retract into the signal channel 221. The movement of the signal core 41 drives the transmission rod 42 to move elastically against the elastic reset mechanism 44, and the transmission rod 42 moves the valve core part 43 downward. When the pressure-holding core 431 moves, its boss 4312 will disengage from the main sealing ring 4331. The gas in the valve core moving hole 32 will then pass through the gap between the boss 4312 and the guide block 433 to the first core 4311. Since the cross-sectional area of ​​the first core 4311 is smaller than that of the second core 4313, the air pressure in the valve core moving hole 32 acts on the upper effective pressure-bearing surface of the boss 4312, causing the pressure-holding core 431 to move away from the upper valve body 10. The direction of the movement causes the vent core 432 to move away from the upper valve body 10. The movement of the vent core 432 causes the sealing part 4321 on it to move and retract into the suction channel 231 of the suction bushing 23 to close the suction channel 231 and prevent molten metal from entering the suction channel 231 (this process completes the closing of the plate servo vacuum valve). Then the boss part 4312 continues to move down to the limit and stops moving, keeping the vent core 432 in the lower position and entering the pressure holding state.

[0051] like Figure 10 and Figure 11 As shown, it also includes two reset rods 50 and two cold mold gas pistons 60.

[0052] Each reset rod 50 is slidably mounted on the lower valve block 21. It should be noted that the lower valve block 21 has rod holes that are adapted to the reset rods 50 to restrict the vertical sliding of the reset rods 50. The bottom of the reset rod 50 contacts the top of the top plate 441, and the top of the reset rod 50 is higher than the top surface of the lower valve block 21. During the mold closing process, the top of the reset rod 50 is pressed down by the mold or a special pressure rod. The reset rod 50, through transmission, presses down on the top plate 441 and pre-compresses the disc spring 442. The disc spring 442 is pre-compressed and does not participate in any action. When the mold opens, the reset rod 50 is released, and the disc spring 442 pops out to complete the reset action.

[0053] Each cold mold gas piston 60 is mounted on the lower valve block 21. It should be noted that the lower valve block 21 has a plug hole adapted to the cold mold gas piston 60 to restrict the vertical sliding of the reset rod 50. The plug hole is connected to an external air source through an air passage and is controlled by external air pressure. The cold mold gas piston 60 is located above the transmission rod 42. It should be noted that during initial mold use, external air pressure drives the cold mold gas piston 60 downwards through the air passage and plug hole. The downward movement of the cold mold gas piston 60 directly presses down the transmission rod 42, thus forcibly pressing down the valve core part 43 through the transmission rod 42, causing the sealing part 4321 to enter the suction channel 231. Regardless of whether the signal core 41 is extended, the suction core remains closed. This function is used in situations where the molten metal has poor fluidity during initial mold use or where there are no special requirements for product quality.

[0054] When the mold opens, the reset rod 50 is released, the elastic reset mechanism 44 extends, and the push transmission rod 42 drives the entire actuator 40 to move upward to the valve body 10 and reset, causing the sealing part 4321 on the vent core 432 to move towards the receiving groove 11. At the same time, the vent part 4322 is connected to the receiving groove 11 and the air extraction channel 231, so that the plate servo vacuum valve is in the open state. At the same time, the pressure holding core 431 moves so that the upper side of the boss part 4312 is attached to the main sealing ring 4331, so that the boss part 4312 is sealed with the guide block 433 through the main sealing ring 4331, and the external constant pressure gas The air enters the valve core moving hole 32 through the constant pressure vent 33. Because the cross-sectional area of ​​the boss part 4312 is larger than that of other parts, under the action of the pressure area difference, the air pressure in the valve core moving hole 32 acts on the lower side of the boss part 4312 to generate an upward thrust, which will drive the valve core part 43 to tend to the upper valve body 10 for holding. This strengthens the force of the plate servo vacuum valve in the open state and prevents the valve core part 43 from moving erroneously due to interference factors such as vibration and vacuum return during operation, thereby improving the steady state effect of the plate servo vacuum valve in the open state.

[0055] When the moving mold and the fixed mold of the die-casting mold are closed, the top of the reset rod 50 is pressed down by the mold. At the same time, the reset rod 50 presses down on the top plate 441 and pre-compresses the disc spring 442. The disc spring 442 is pre-compressed and does not participate in any action. The signal core 41 and the valve core part 43 remain stationary and are supported entirely by the upward pushing force of the boss part 4312 under air pressure.

[0056] When the vacuum pump is started, the mold cavity is evacuated through the evacuation port 213, the vent 232 on the evacuation bushing 23, the evacuation channel 231 on the evacuation bushing 23, the vent 4322, and the receiving groove 11. After the die-casting mold is evacuated, molten metal is injected into the die-casting mold. After the molten metal fills the mold cavity, it enters the receiving groove 11. When the molten metal enters the receiving groove 11, it impacts the signal core 41, triggering the signal core 41 to move and retract into the signal channel 221. The movement of the signal core 41 drives the valve core part 43 to move down through the actuator 40, causing the boss part 4312 to disengage from the main sealing ring 4331.

[0057] The gas in the valve core movable hole 32 passes through the gap between the boss 4312 and the guide block 433 to the first core 4311. The air pressure in the valve core movable hole 32 acts on the upper side of the boss 4312, generating a downward thrust (the original upward pressure instantly becomes a downward pressure, and the direction of the force changes). This pushes the pressure-holding core 431 away from the upper valve body 10, which in turn drives the venting core 432 to move synchronously, causing the sealing part 4321 to retract into the suction channel 231 to close the suction channel 231, and the plate servo vacuum valve is closed in place. Then, under the action of air pressure, the boss 4312 continues to move downward to its limit, generating a downward force to keep the venting core 432 in the lower position, preventing the valve core part 43 from moving erroneously due to interference factors such as vibration and metal liquid impact fluctuations during operation, thereby improving the stability of the plate servo vacuum valve in the closed state.

[0058] The above embodiments are exemplary and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art without creative effort should be included within the protection scope of the present invention.

Claims

1. A plate-type servo vacuum valve, comprising an upper valve body (10) having a receiving groove (11) capable of communicating with the exhaust port of a die-casting mold, characterized in that, Also includes: The lower valve body (20) is fastened to the upper valve body (10). The lower valve body (20) has a signal channel (221), an air extraction channel (231) communicating with the receiving groove (11), an air inlet (232) communicating with the air extraction channel (231), and an air extraction port (213) communicating with the air inlet (232). The air extraction port (213) is used to communicate with the air extraction end of an external vacuum pump. A valve block seat (30) is installed on the lower valve body (20), and the valve block seat (30) is provided with a mating cavity (31) and a valve core moving hole (32). The execution structure (40) includes a signal core (41) slidably disposed in the signal channel (221), a transmission rod (42) hinged on the valve block seat (30), a valve core part (43) slidably disposed on the valve core movable hole (32), and an elastic reset mechanism (44) installed on the mating cavity (31). The central axis of the signal core (41) is coplanar and parallel to the central axis of the valve core part (43). The signal core (41) contacts the upper side of the transmission rod (42). One end of the transmission rod (42) is engaged with the valve core part (43). The lower side of the transmission rod (42) abuts against the movable end of the elastic reset mechanism (44). The valve core part (43) has a pressure holding core (431) and a venting core (432) connected to the pressure holding core (431). The venting core (432) has a blocking part (4321) and a venting part (4322). The venting part (4322) is connected to the receiving groove (11) and the air extraction channel (231). The valve core part (43) can move down to close the air extraction channel (231) by the blocking part (4321).

2. The plate-type servo vacuum valve according to claim 1, characterized in that, The valve core movable hole (32) has an upper hole (321) and a lower hole (322) communicating with the upper hole (321). The pressure holding core (431) has a first core (4311), a boss (4312) connected to the first core (4311), and a second core (4313) connected to the boss (4312). The second core (4313) is slidably connected in the lower hole (322).

3. The plate-type servo vacuum valve according to claim 2, characterized in that, The cross-sectional area of ​​the boss portion (4312) is greater than the cross-sectional area of ​​the second core portion (4313), and the cross-sectional area of ​​the second core portion (4313) is greater than the cross-sectional area of ​​the first core portion (4311). The valve block seat (30) also has a constant pressure vent (33) that communicates with the valve core movable hole (32), and the constant pressure vent (33) is connected to an external constant pressure air source; The valve core part (43) also has a guide block (433), which is interference-sealed on the inner wall of the upper hole (321). The guide block (433) has a clearance hole in the middle for the first core part (4311) to pass through. The bottom of the guide block (433) is provided with a main sealing ring (4331). The guide block (433) is sealed to the edge of the boss part (4312) through the main sealing ring (4331).

4. The plate-type servo vacuum valve according to claim 3, characterized in that, The first core (4311) has a first transmission hole (43111) and a plug hole. The vent core (432) is inserted into the plug hole of the first core (4311). The vent core (432) has a second transmission hole (4323). The transmission rod (42) passes through the first transmission hole (43111) and is inserted into the second transmission hole (4323).

5. The plate-type servo vacuum valve according to claim 1, characterized in that, The lower valve body (20) includes a lower valve block (21). The lower valve block (21) is provided with a signal sleeve hole (211), a suction sleeve hole (212), a suction port (213) communicating with the suction sleeve hole (212), and a limiting hole (214) communicating with the signal sleeve hole (211). The diameter of the signal sleeve hole (211) is smaller than the diameter of the limiting hole (214). A signal bushing (22) is interference-fitted in the signal sleeve hole (211). The signal channel (221) is located in the signal bushing (22). The top of the signal channel (221) is connected to the receiving groove (11). The bottom of the signal channel (221) is connected to the limiting hole (214). A suction bushing (23) is interference-fitted in the suction sleeve hole (212). The suction channel (231) and the vent (232) are both located on the suction bushing (23).

6. The plate-type servo vacuum valve according to claim 5, characterized in that, The signal core (41) has an upper sliding part (411) and a lower sliding part (412) connected to the upper sliding part (411). The diameter of the lower sliding part (412) is larger than the diameter of the upper sliding part (411). The upper sliding part (411) is slidably disposed in the signal channel (221), and the lower sliding part (412) is slidably connected in the limiting hole (214).

7. The plate-type servo vacuum valve according to claim 1, characterized in that, A sealing groove is formed on the outer periphery of the signal core (41), and a heat-resistant sealing ring is embedded in the sealing groove. The outer periphery of the heat-resistant sealing ring slides and seals against the inner wall of the signal channel (221).

8. The plate-type servo vacuum valve according to claim 1, characterized in that, The bottom of the signal core (41) is provided with a top block (413), and one end of the transmission rod (42) is hinged to the valve block seat (30) through a rotating shaft.

9. The plate-type servo vacuum valve according to any one of claims 1-8, characterized in that, The elastic reset mechanism (44) includes a top plate (441) slidably connected in the mating cavity (31). The top of the top plate (441) abuts against the lower side of the transmission rod (42). A disc spring (442) is fixedly installed at the bottom of the top plate (441). The bottom of the disc spring (442) abuts against the bottom of the mating cavity (31). The elastic force of the disc spring (442) can drive the top plate (441) to move upward.

10. The plate-type servo vacuum valve according to claim 9, characterized in that, It also includes two reset rods (50) and two cold mold gas pistons (60), which are all slidably mounted on the lower valve body (20). The reset rods (50) can be pressed down and moved when the mold is closed. The bottom of the reset rods (50) contacts the top of the top plate (441). The lower valve body (20) is provided with plug holes that are adapted to the cold mold gas pistons (60). The plug holes are connected to an external air source through air passages. The cold mold gas pistons (60) are located above the transmission rod (42).

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