High vacuum die casting mold for an engine crankcase

Abstract

The application relates to the technical field of engine crankcase casting molds, in particular to a high-vacuum die casting mold for an engine crankcase, which comprises an upper mold, a lower mold, a vacuum-pumping pipeline, an external vacuum pump and an intelligent system, the vacuum-pumping pipeline is arranged on the upper mold and is in communication with a mold cavity of the upper mold, and a one-way valve is arranged on the vacuum-pumping pipeline; the intelligent system comprises a sensing and detecting unit for detecting the sealing and vacuum state of the mold, a compensation unit for compensating the sealing structure, and a controller for receiving the detection signals and controlling the compensation action; the vacuum degree of the mold cavity can be stably maintained, the generation of defects such as blowholes and shrinkage holes in the engine crankcase casting is obviously reduced, the compactness, air tightness and overall quality of the casting are improved, and a prerequisite condition for implementing vacuumizing on the mold cavity through the vacuum pump is provided.

Description

Technical Field

[0001] This invention relates to the field of engine crankcase casting mold technology, and particularly to a high-vacuum die-casting mold for engine crankcases. Background Technology

[0002] As a core load-bearing component of the engine, the crankcase plays a crucial role in supporting the crankshaft, sealing lubricating oil, and mounting engine accessories. Its structure is highly complex, with uneven wall thickness, and it places extremely stringent requirements on the density, airtightness, and dimensional accuracy of the castings. Currently, mass production of engine crankcases primarily utilizes die casting. High-vacuum die casting technology, in particular, has become the mainstream process for high-end engine crankcase production due to its ability to effectively reduce internal defects such as porosity, shrinkage cavities, and shrinkage porosity, significantly improving the mechanical properties of the castings. The vacuum level of the die-casting mold cavity directly determines the quality of the product; the higher the vacuum level, the fewer air bubbles on the crankcase surface, resulting in higher product quality.

[0003] Existing high-vacuum die-casting molds have significant shortcomings: they lack a sealing detection function after mold closing, making it impossible to detect local sealing failures after mold closing; they lack a precise sealing pressure compensation mechanism, making it impossible to achieve vacuum degree detection and compensation control; this results in a lack of reference for mold vacuuming, insufficient vacuuming, and a large amount of air remaining in the cavity, causing defects such as porosity and shrinkage in crankcase castings. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a high-vacuum die-casting mold for an engine crankcase, comprising an upper mold, a lower mold, a vacuum pipeline, an external vacuum pump, and an intelligent system. The vacuum pipeline is located in the upper mold and connected to its cavity, and a one-way valve is provided on the vacuum pipeline. The intelligent system includes a sensing unit for detecting the mold's sealing and vacuum status, a compensation unit for compensating the pressure of the sealing structure, and a controller for receiving detection signals and controlling the compensation action. The controller is electrically connected to the pressure sensor of the sensing unit and the booster pump of the compensation unit, respectively, and is used to process the detection data and output control commands. An annular cavity is formed on the overlapping surface of the lower mold. A hollow sealing ring is fixedly installed in the annular cavity. The sensing and detection unit includes multiple detection positions arranged along the annular cavity. A pressure sensor is installed in each detection position. The detection end of the pressure sensor is facing upward and abuts against the side of the hollow sealing ring located in the annular cavity. It is used to detect the pressure change of the corresponding detection area of ​​the hollow sealing ring in real time, so as to provide feedback on the sealing status of the area and transmit the sealing detection status to the controller through pressure detection data. The compensation unit includes multiple compensation pipes, multiple solenoid valves, multiple branch pipes, and a main pipe; the inner end of each compensation pipe is connected to a detection position, and the outer end of each compensation pipe extends to the outside of the mold, and a solenoid valve is installed at the outer end of each compensation pipe; the other end of each solenoid valve is connected to a branch pipe, and the other ends of all the branch pipes converge at the main pipe, and the other end of the main pipe is connected to the booster pump.

[0005] Preferably, one end of the vacuum line connecting to the cavity is flush with the cavity wall and located at the highest point of the cavity wall. An assembly cavity is provided on the top of the upper mold. The vacuum line passes through the assembly cavity. The one-way valve is installed on the vacuum line and is sealed to the assembly cavity with sealant along with the vacuum line.

[0006] Preferably, the annular cavity is formed on the overlapping surface of the lower mold around the core of the lower mold, and the annular cavity is far away from the core.

[0007] Preferably, the top surface of the hollow sealing ring is higher than the overlapping surface of the lower mold, and the upward protrusion is 5-8mm.

[0008] Preferably, each of the detection positions has a countersunk hole facing downwards, a heat insulation sleeve is installed in each countersunk hole, and a pressure sensor is embedded in each heat insulation sleeve. The top of the countersunk hole communicates with the annular cavity, and the sensing end of the pressure sensor abuts against the bottom surface of the hollow sealing ring.

[0009] Preferably, the overlapping surface of the lower mold has at least two recessed cavities, and the inner end of each recessed cavity has an oblique hole communicating with each corresponding recessed hole. The electrical connection line of each pressure sensor extends from the corresponding oblique hole into the nearby recessed cavity.

[0010] Preferably, the detection position is provided with a pipeline channel on the lower mold that communicates with the corresponding cavity. Each pipeline channel is provided with a compensation pipe. The compensation pipe is inserted into the annular cavity through the corresponding pipeline channel and is connected to the hollow sealing ring relative to the corresponding detection position.

[0011] Preferably, the top surface of the hollow sealing ring is an upwardly convex arc-shaped surface, and the top of its cavity is also an upwardly convex arc-shaped surface.

[0012] The advantages of this invention compared to the prior art are: In this invention, during mold closing, pressure sensors at each detection point are used to detect the pressure at each point, obtaining the sum of the pressures at all detection points. Then, intelligent control calculates the average value of the total pressure, comparing it with a threshold. When the pressure at a certain detection point is less than the threshold, the controller sends a command to the booster pump, which delivers gas through the compensation pipe corresponding to that detection point to the detection point of the pressure defect in the hollow sealing ring, achieving point-to-point compensation and efficiently balancing the overall sealing pressure. This continues until the pressure value at that detection point reaches the average value (threshold) of the pressures at other detection points, proving that the mating surface after mold closing is tightly sealed. At this point, the controller sends a command to the vacuum pump, which then performs vacuuming of the cavity through the vacuuming pipeline. This achieves the goal of first detecting the airtightness and compensating the pressure at the mating surface of the upper and lower molds, and then performing vacuuming of the cavity. During vacuuming, external ambient gas is prevented from entering the cavity, ensuring effective vacuuming.

[0013] Therefore, this invention, through the integration of an intelligent system and the layout matching function of multiple detection positions, achieves real-time, localized detection and precise pressure compensation of the sealing status of the high-vacuum die-casting mold for engine crankcases. This solution effectively solves the problems of traditional molds failing to detect localized sealing failures after mold closing and lacking a precise compensation mechanism. As a result, the vacuum level of the mold cavity is maintained stably, significantly reducing the generation of defects such as porosity and shrinkage cavities inside the engine crankcase casting, thereby improving the density, airtightness, and overall quality of the casting, and providing the necessary prerequisite for subsequent vacuuming of the cavity using a vacuum pump. Attached Figure Description

[0014] Figure 1 A schematic diagram from a first-view perspective of a high-vacuum die-casting mold for an engine crankcase provided for an embodiment of the present invention; Figure 2 A schematic diagram from a second perspective of a high-vacuum die-casting mold for an engine crankcase provided for an embodiment of the present invention; Figure 3 A schematic diagram of a high-vacuum die-casting mold for an engine crankcase, provided for an embodiment of the present invention; Figure 4 A high-vacuum die-casting mold for an engine crankcase provided for an embodiment of the present invention is made of Figure 3 The enlarged schematic diagram of a detection position in section A is shown, where one detection position represents the consistent structure of all detection positions; Figure 5 A high-vacuum die-casting mold for an engine crankcase provided for an embodiment of the present invention is made of Figure 4 A schematic diagram of the front view after horizontal sectioning.

[0015] In the diagram: 1. Upper mold; 2. Lower mold; 3. Vacuum piping; 4. External vacuum pump; 5. One-way valve; 6. Controller; 7. Pressure sensor; 8. Booster pump; 9. Hollow sealing ring; 10. Detection position; 11. Compensation pipe; 12. Solenoid valve; 13. Branch pipe; 14. Main pipe; 15. Assembly cavity; 16. Core; 17. Countersunk hole; 18. Heat insulation sleeve; 19. Recessed cavity; 20. Angled hole; 21. Annular cavity; 22. Piping channel. Detailed Implementation

[0016] The above and other embodiments and advantages of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0017] In one implementation, such as Figures 1-5 As shown: This embodiment provides a high-vacuum die-casting mold for an engine crankcase, including an upper mold 1, a lower mold 2, a vacuum pipeline 3, an external vacuum pump 4, and an intelligent system. The vacuum pipeline 3 is located on the upper mold 1 and connected to its cavity; a one-way valve 5 is provided on the vacuum pipeline 3. The intelligent system includes a sensing unit for detecting the mold's sealing and vacuum status, a compensation unit for compensating the pressure of the sealing structure, and a controller 6 for receiving detection signals and controlling the compensation action. The controller 6 is electrically connected to the pressure sensor 7 of the sensing unit and the booster pump 8 of the compensation unit, respectively, and is used to process detection data and output control commands. An annular cavity 21 is formed on the overlapping surface of the lower mold 2. A hollow sealing ring 9 is fixedly installed inside the annular cavity 21. The sensing and detection unit includes multiple detection positions 10 arranged along the annular cavity 21, and a pressure sensor 7 is installed in each detection position 10. These detection positions 10 can be evenly distributed at different positions in the annular cavity 21. For example, a detection position 10 can be set at certain angles to cover the entire annular sealing area. The pressure sensor 7 can be a piezoresistive sensor or a piezoelectric sensor, with its sensing end facing upward and abutting against the side of the hollow sealing ring 9 located inside the annular cavity 21. It is used to detect the pressure change in the detection area corresponding to the hollow sealing ring 9 in real time, so as to provide feedback on the sealing status of the area, and transmit the sealing detection status to the controller 6 through pressure detection data. The compensation unit includes multiple compensation pipes 11, multiple solenoid valves 12, multiple branch pipes 13, and a main pipe 14. The inner end of each compensation pipe 11 is connected to a detection position 10, and the outer end extends to the outside of the mold. Each compensation pipe 11 has a corresponding solenoid valve 12 installed at its outer end. The other end of each solenoid valve 12 is connected to a branch pipe 13. The other ends of all branch pipes 13 converge at the main pipe 14, and the other end of the main pipe 14 is connected to the booster pump 8.

[0018] The upper mold 1 and lower mold 2 constitute the main body of the die-casting mold. After they are closed, they form the cavity and core 16 for casting the engine crankcase. A vacuum line 3 is used to extract air from the mold cavity to create a vacuum environment. The outer end of this line is connected to an external vacuum pump 4 to achieve vacuuming of the cavity. The external vacuum pump 4 is a device that provides vacuum suction, expelling gas from the mold cavity through the vacuum line 3. The intelligent system is an integrated control unit responsible for detecting the mold sealing status, monitoring the vacuum level, and compensating for pressure on the sealing structure.

[0019] The sensing and detection unit, part of the intelligent system, monitors pressure changes in the overlapping area of ​​the upper and lower molds in real time during mold closing and feeds back the pressure signal to controller 6 to assess the sealing status. The compensation unit, also part of the intelligent system, compensates for localized or overall pressure on the mold's sealing structure based on feedback from the sensing and detection unit, enhancing sealing performance. Controller 6, the core of the intelligent system, receives detection signals from the sensing and detection unit, processes the data, and controls the operation of the compensation unit according to preset logic.

[0020] The annular cavity 21 is an annular groove formed on the mating surface of the lower mold 2. It houses and retains a hollow sealing ring 9, which can be made of an elastic material, such as silicone rubber or fluororubber. Its hollow structure allows it to deform under pressure to accommodate minor unevenness on the mold surface, thus providing an effective seal. The hollow sealing ring 9, fixed within the annular cavity 21, enhances the sealing effect between the mating surfaces when the molds are closed.

[0021] The detection positions 10 are multiple detection points set along the annular cavity 21, and each detection position 10 is equipped with a pressure sensor 7. During mold closing, the two molds first overlap with the hollow sealing ring 9. At this time, the hollow sealing ring 9 will descend and compress until the overlapping surfaces of the two molds are completely aligned. At this time, the hollow sealing ring 9 reaches its limit compression and generates pressure. The pressure is transmitted to all the pressure sensors 7 through the multiple detection positions 10. That is, the hollow sealing ring 9 is the force-bearing area, and these pressure sensors 7 are the sensing points, so that these detection positions 10 complete the pressure detection. The compensation pipe 11 is part of the compensation unit. When the pressure at a certain detection position 10 is less than the threshold of the controller 6, the controller 6 sends a command to the booster pump 8. Gas is then delivered to the detection position 10 of the hollow sealing ring 9 through the compensation pipe 11 corresponding to the detection position 10, achieving point-to-point compensation and efficiently balancing the overall sealing pressure until the pressure value on the sensor at the detection position 10 reaches the average value (threshold) of the sum of the pressures at the other detection positions 10. This threshold is the sealing requirement of the hollow sealing ring 9 between the upper and lower overlapping surfaces through tight pressing. At this time, after the upper and lower molds 2 are closed, their overlapping surfaces are tightly sealed. The controller 6 then sends a command to the vacuum pump 4. The vacuum pump 4 then performs vacuuming operations on the cavity through the vacuuming pipeline 3. The vacuum pump 4 is equipped with a pressure gauge. Vacuuming stops when the negative pressure reaches the threshold. After the airtightness test and pressure compensation of the overlapping surfaces of the upper and lower molds 2 are performed first, the cavity is then vacuumed. During vacuuming, it is ensured that external ambient gas does not enter the cavity to ensure effective vacuuming.

[0022] It should be further explained that the detection end of the pressure sensor 7 is positioned upwards against the side of the hollow sealing ring 9 located within the annular cavity 21, for real-time detection of pressure changes in the corresponding detection area of ​​the hollow sealing ring 9. Through this contact method, the pressure sensor 7 can directly sense the pressure on the sealing ring in the mold-closed state, thereby providing feedback on the sealing status of that area. For example, when the pressure in a certain area of ​​the sealing ring is lower than a preset threshold, it indicates that there may be a problem with the seal. These sealing detection statuses are transmitted to the controller 6 via pressure detection data. The compensation unit includes multiple compensation pipes 11, multiple solenoid valves 12, multiple branch pipes 13, and a main pipe 14. These components work together to achieve precise pressure compensation for the sealing area. The inner end of each compensation pipe 11 is connected to a detection position 10, and its outer end extends to the outside of the mold. Each compensation pipe 11 has a corresponding solenoid valve 12 installed at its outer end. The compensation pipe 11 can be a high-pressure resistant flexible or rigid pipe, and its inner end can be easily inserted into or threaded into the hollow sealing ring 9 near the detection position 10 to achieve fluid communication. The solenoid valve 12 can be either normally closed or normally open, and is controlled to open or close by an electrical signal sent by the controller 6.

[0023] It should be further explained that: the solenoid valve 12 is a control element installed on the compensation pipe 11, used to precisely control the flow of the compensation fluid according to the control command of the controller 6. Furthermore, in order to control the corresponding compensation pipe 11 according to the corresponding detection position 10, each compensation pipe 11 needs to be equipped with a solenoid valve 12. The branch pipe 13 is a pipe connecting the solenoid valve 12 to the main pipe 14, used to collect the compensation fluid from different compensation pipes 11. The main pipe 14 is the main pipe that collects the compensation fluid from all branch pipes 13, and is connected to the booster pump 8 to achieve shared air supply.

[0024] It should be further noted that the vacuum pump and booster pump described in this invention are existing external third-party devices, and the controllers are mostly installed in the electrical control part of the compressor. They are all mature existing technologies, and can be used after purchase, debugging and installation. They do not need to be described in detail in the attached drawings.

[0025] A one-way valve 5 is installed on the vacuum line 3. This one-way valve 5 can be a simple ball valve. When the external vacuum pump 4 performs vacuuming of the cavity, the ball valve opens to allow gas to escape; when vacuuming stops, the one-way valve 5 closes to prevent external air backflow. When the upper and lower molds 2 are closed to detect the sealing pressure, the one-way valve 5 is also closed, thus maintaining a constant gas pressure in the mold cavity. The controller 6 establishes an electrical connection with the pressure sensor 7 of the sensing unit and the booster pump 8 of the compensation unit. The controller 6 receives detection signals from the pressure sensor 7, analyzes and processes these data, and outputs control commands to the booster pump 8 based on the processing results. For example, the controller 6 can be a microprocessor that communicates with the sensor and the booster pump 8 via wired or wireless means.

[0026] This implementation method, through the integration of an intelligent system, achieves real-time, localized detection and precise pressure compensation of the sealing status of the high-vacuum die-casting mold for the engine crankcase. This solution effectively solves the problems of traditional molds failing to detect localized sealing failures after mold closing and lacking a precise compensation mechanism. As a result, the vacuum level of the mold cavity is maintained stably, significantly reducing the generation of defects such as porosity and shrinkage cavities inside the engine crankcase casting, thereby improving the density, airtightness, and overall quality of the casting. This provides the necessary prerequisite for subsequent vacuuming of the cavity using vacuum pump 4. Existing high-vacuum die-casting molds cannot perform pre-testing of the sealing of the mating surfaces after mold closing, allowing external air to still enter the cavity. If a vacuuming operation is performed, external gas will be drawn into the cavity, rendering the vacuuming operation futile. Consequently, gas will still mix into the product during casting, forming defects such as porosity and shrinkage, affecting product quality. This invention solves this problem by first testing the airtightness of the mating surfaces during mold closing, then using the compensation pipe 11 to replenish the overlapping pressure in the suspected leakage area to ensure the sealing of the mating surfaces, and then performing a vacuuming operation. In another embodiment, one end of the vacuum line 3 is flush with the cavity wall and located at the highest point of the cavity wall. The top of the upper mold 1 has an assembly cavity 15. The vacuum line 3 passes through the assembly cavity 15. The one-way valve 5 is installed on the vacuum line 3 and is sealed in the assembly cavity 15 with the vacuum line 3 by sealant. The core innovation of this embodiment lies in systematically eliminating air stagnation dead zones and maintaining a stable vacuum environment by setting one end of the vacuum pipe 3 connected to the cavity to be flush with the cavity wall and precisely positioned at the highest point, combined with the integrated sealing installation structure of the assembly cavity 15. Specifically, the design of the end of the vacuum pipe 3 connected to the cavity to be flush with the cavity wall avoids the gas stagnation area caused by the protruding port of the traditional pipe, ensuring that the gas in the cavity is discharged without dead zones; at the same time, the port is located at the highest point of the cavity wall, which facilitates the efficient removal of residual air that naturally accumulates at the top due to density differences, significantly improving the vacuuming efficiency. The assembly cavity 15 opened at the top of the upper mold 1 provides a dedicated installation space for the vacuum pipe 3, making the pipe layout more compact and reasonable, and simplifying the assembly process. The one-way valve 5 is installed on the vacuum pipe 3 to effectively prevent external air backflow and maintain a stable vacuum level in the cavity; in addition, this setting mode prevents molten material backflow when the product is injected into the mold cavity. In addition, the one-way valve 5 is installed on the vacuum line 3 and is sealed in the assembly cavity 15 with sealant along with the vacuum line 3, which significantly improves the density, airtightness and dimensional accuracy of the casting, meeting the product quality requirements of high-end engine crankcases.

[0027] In another embodiment, the annular cavity 21 is formed on the overlapping surface of the lower mold 2 around the periphery of the core 16 of the lower mold 2, and the annular cavity 21 is far away from the core 16.

[0028] The annular cavity 21 is located away from the core 16, effectively preventing the high temperature near the core 16 from being transferred to the annular cavity 21, and then directly transferred to the hollow sealing ring 9. In actual assembly, the mold size is relatively large, often assembled from multiple modules. This assembly mode is common in casting molds and is beneficial for CNC roughing and finishing of the mold core 16. For example, the lower mold 2 in this invention also adopts this mold assembly method. The module with the annular cavity 21 uses or installs heat insulation material, and the annular cavity 21 is machined by a CNC milling machine. In this way, the annular cavity 21 not only provides heat insulation away from the core 16, but also reduces heat transfer between modules, ensuring that the hollow sealing ring 9 does not deform.

[0029] In another embodiment, the top surface of the hollow sealing ring 9 is higher than the overlapping surface of the lower mold 2, and the upward protrusion is 5-8 mm.

[0030] The top surface of the hollow sealing ring 9 is designed to be higher than the mating surface of the lower mold 2, allowing the sealing ring to actively conform to the surface of the upper mold 1 during mold closing operations. This increases the contact area and pressure distribution uniformity, thereby reducing the risk of leakage caused by local gaps. Furthermore, the height of the upward protrusion is limited to the range of 5 mm to 8 mm. When it first comes into contact with the mating surface of the upper mold 1 during mold closing, it can be compressed and deformed. In addition to achieving a seal between the mating surfaces of the upper and lower molds 2, its compression action also feeds back the pressure status to the sensing end of the pressure sensor 7 at each detection position 10, making the pressure value detection signal more sensitive.

[0031] In another embodiment, each detection position 10 has a countersunk hole 17 facing downwards, a heat insulation sleeve 18 is installed in each countersunk hole 17, and a pressure sensor 7 is embedded in each heat insulation sleeve 18. The top of the countersunk hole 17 communicates with the annular cavity 21, and the sensing end of the pressure sensor 7 abuts against the bottom surface of the hollow sealing ring 9.

[0032] The above technical solution effectively isolates high-temperature interference and ensures the accuracy of pressure detection. Specifically, the countersunk hole 17 provides physical isolation space, reducing the direct conduction of heat source to the pressure sensor 7; the heat insulation sleeve 18 further blocks heat transfer, preventing the pressure sensor 7 from drifting or failing due to high mold temperature; the pressure sensor 7 is firmly embedded in the heat insulation environment, maintaining detection stability; the top of the countersunk hole 17 communicates with the annular cavity 21, allowing the pressure sensor 7 to directly respond to pressure fluctuations within the annular cavity 21 and reflect sealing changes in real time; the sensing end of the pressure sensor 7 abuts against the bottom surface of the hollow sealing ring 9, achieving direct physical contact and accurately capturing local sealing pressure data, providing a reliable basis for sealing compensation. Due to the above structure, this application achieves accurate detection of local sealing pressure changes in the mold under high-temperature die-casting conditions, avoiding detection deviations caused by sensor heat, thus reliably feeding back the sealing failure state, providing an accurate reference for vacuum compensation control, and significantly reducing the risk of defects such as porosity and shrinkage in the crankcase casting.

[0033] In another embodiment, the overlapping surface of the lower mold 2 has at least two recessed cavities 19. The inner end of each recessed cavity 19 has an oblique hole 20 communicating with each corresponding countersunk hole 17. The electrical connection wire of each pressure sensor 7 extends from the oblique hole 20 into the nearby recessed cavity 19. Each detection position 10 has a corresponding pipe channel 22 on the lower mold 2 communicating with the corresponding recessed cavity 19. Each pipe channel 22 has a compensation pipe 11, which is inserted into the annular cavity 21 through the corresponding pipe channel 22 and communicates with the hollow sealing ring 9 relative to the corresponding detection position 10.

[0034] By combining each detection position 10 with an independent pipeline channel 22 and compensation pipe 11 in a one-to-one correspondence, rapid pressure compensation can be performed on a specific area when a local sealing failure is detected, thereby maintaining the integrity of the mold seal, preventing vacuum leakage, and reducing casting defects. Specifically, a pipeline channel 22 is provided in the nearby cavity 19 corresponding to the detection position 10, so that the compensation path can be configured independently for each detection area; the pipeline channel 22 is connected to the cavity 19, and the compensation pipe 11 is housed in the pipeline channel 22. The outer end of the compensation pipe 11 and the solenoid valve 12 on it are housed in the nearby cavity 19 to prevent the compensation pipe 11 from being crushed when the upper mold 1 closes the lower mold 2.

[0035] In another embodiment, the top surface of the hollow sealing ring 9 is an upwardly convex arc-shaped surface, and the top of its cavity is also an upwardly convex arc-shaped surface.

[0036] During the mold closing process, when the upper mold 1 is pressed down, the arc-shaped surface can flexibly deform and gradually fit the surface of the upper mold 1, forming a continuous and uniform contact pressure distribution, effectively reducing local gaps caused by minor surface irregularities; at the same time, the top of its cavity is also designed as an upward-convex arc-shaped surface, which makes the deformation of the internal cavity more uniform when the sealing ring is under pressure, avoiding stress concentration, thereby maintaining a stable sealing state and preventing sealing failure caused by uneven pressure distribution. When the compensation pipe 11 is filled with gas corresponding to its detection position 10, the top arc-shaped surface expands rapidly, and the sealing pressure (sealing degree) of the detection position 10 is quickly and efficiently compensated.

[0037] Working principle: The upper mold 1 moves and closes relative to the lower mold 2 under the drive of the press. The top surface of the hollow sealing ring 9 is an upwardly convex arc surface, and the top of its cavity is also an upwardly convex arc surface, which helps to form a tighter contact with the upper mold 1 when the mold is closed. After the mold closes, the intelligent system starts to work. The sensing and detection unit detects the sealing status of the mold in real time. Multiple detection positions 10 are set along the annular cavity 21, and each detection position 10 has a countersunk hole 17. A heat insulation sleeve 18 is installed in each countersunk hole 17, and a pressure sensor 7 is embedded in each heat insulation sleeve 18. The sensing ends of these pressure sensors 7 abut against the bottom surface of the hollow sealing ring 9 to detect the pressure changes in the corresponding detection area of ​​the hollow sealing ring 9 in real time. These pressure sensors 7 transmit the detected sealing status to the controller 6 through pressure detection data. The controller 6 receives and processes the pressure detection data from the sensing and detection unit. If the controller 6 detects that the pressure sensor 7 at a certain detection position 10 is lower than the average value of the data detected by all detection positions 10 (i.e., the threshold), it indicates that the sealing of that detection position 10 is questionable. The controller 6 immediately outputs a control command, the booster pump 8 starts, and at the same time, the solenoid valve 12 on the corresponding compensation pipe 11 automatically opens. The corresponding compensation pipe 11 provides compensation gas to the questionable detection position 10 on the hollow sealing ring 9. The gas enters this detection position 10 of the hollow sealing ring 9, rapidly increasing the internal pressure in the area corresponding to that detection position 10, causing the hollow sealing ring 9 to expand upward in a local area, accelerating the compensation speed, and efficiently balancing all areas on both the upper and lower surfaces. The overall sealing pressure is maintained until the pressure value on the sensor at detection position 10 reaches the average value (threshold) of the pressure at other detection positions 10. This threshold is the sealing requirement of the hollow sealing ring 9 between the upper and lower mating surfaces through tight compression. At this point, after the upper and lower molds 2 are closed, their mating surfaces are tightly sealed. The controller 6 then issues a command to the vacuum pump 4, which then performs vacuuming operations on the cavity through the vacuuming pipeline 3. The vacuum pump 4 is equipped with a pressure gauge. Vacuuming stops when the negative pressure reaches the threshold. First, the airtightness of the mating surfaces of the upper and lower molds 2 is tested and pressure compensation is performed before vacuuming the cavity. During vacuuming, it is ensured that external ambient air does not enter the cavity to ensure effective vacuuming. Compared with the prior art, this invention can effectively solve the problems of undetectable local sealing failures of molds, lack of precise compensation, and insufficient vacuuming, and significantly reduce defects such as porosity and shrinkage cavities inside castings.

[0038] The above orientation references do not represent the specific orientations of each component in this implementation scheme. This implementation scheme is only for the convenience of describing the scheme and to make relative descriptions based on the orientations of the references. In reality, the specific orientations of each component are based on their actual installation and use, as well as the orientation descriptions that are customary to those skilled in the art. This is hereby stated.

[0039] The specific embodiments described above further illustrate the inventive purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-vacuum die-casting mold for an engine crankcase, comprising an upper mold (1), a lower mold (2), a vacuum pipeline (3), an external vacuum pump (4), and an intelligent system, characterized in that: The vacuum pipeline (3) is located on the upper mold (1) and is connected to the cavity of the upper mold (1). A one-way valve (5) is provided on the vacuum pipeline (3). The intelligent system includes a sensing and detection unit for detecting the sealing and vacuum status of the mold, a compensation unit for compensating the pressure of the sealing structure, and a controller (6) for receiving detection signals and controlling the compensation action. The controller (6) is electrically connected to the pressure sensor (7) of the sensing and detection unit and the booster pump (8) of the compensation unit, respectively, and is used to process the detection data and output control commands. An annular cavity (21) is provided on the overlapping surface of the lower mold (2). A hollow sealing ring (9) is fixedly installed in the annular cavity (21). The sensing and detection unit includes multiple detection positions (10) arranged along the annular cavity (21). A pressure sensor (7) is installed in each detection position (10). The detection end of the pressure sensor (7) is facing upward and abuts against the side of the hollow sealing ring (9) located in the annular cavity (21). It is used to detect the pressure change of the detection area corresponding to the hollow sealing ring (9) in real time, so as to provide feedback on the sealing status of the area and transmit the sealing detection status to the controller (6) through pressure detection data. The compensation unit includes multiple compensation pipes (11), multiple solenoid valves (12), multiple branch pipes (13), and a main pipe (14); the inner end of each compensation pipe (11) is connected to a detection position (10), and the outer end extends to the outside of the mold. Each compensation pipe (11) has a solenoid valve (12) installed at its outer end. The other end of each solenoid valve (12) is connected to a branch pipe (13), and the other ends of all branch pipes (13) are connected to the main pipe (14). The other end of the main pipe (14) is connected to the booster pump (8).

2. The high-vacuum die-casting mold for an engine crankcase according to claim 1, characterized in that, The vacuum pipeline (3) is flush with the cavity wall at one end and located at the highest point of the cavity wall. The top of the upper mold (1) has an assembly cavity (15). The vacuum pipeline (3) passes through the assembly cavity (15). The one-way valve (5) is installed on the vacuum pipeline (3) and is sealed to the assembly cavity (15) with the vacuum pipeline (3) by sealant.

3. The high-vacuum die-casting mold for an engine crankcase according to claim 2, characterized in that, The annular cavity (21) is formed on the overlapping surface of the lower mold (2) around the core (16) of the lower mold (2), and the annular cavity (21) is far away from the core (16).

4. The high-vacuum die-casting mold for an engine crankcase according to claim 3, characterized in that, The top surface of the hollow sealing ring (9) is higher than the overlapping surface of the lower mold (2), and the upward protrusion height is 5-8 mm.

5. The high-vacuum die-casting mold for an engine crankcase according to claim 4, characterized in that, Each of the detection positions (10) has a countersunk hole (17) facing downwards. A heat insulation sleeve (18) is installed in each of the countersunk holes (17). A pressure sensor (7) is embedded in each of the heat insulation sleeves (18). The top of the countersunk hole (17) is connected to the annular cavity (21). The sensing end of the pressure sensor (7) is pressed against the bottom surface of the hollow sealing ring (9).

6. The high-vacuum die-casting mold for an engine crankcase according to claim 5, characterized in that, The overlapping surface of the lower mold (2) has at least two recessed cavities (19). The inner end of the recessed cavity (19) is provided with an oblique hole (20) that communicates with each of the corresponding recessed holes (17). The electrical connection line of each pressure sensor (7) extends from the corresponding oblique hole (20) into the nearby recessed cavity (19).

7. The high-vacuum die-casting mold for an engine crankcase according to claim 6, characterized in that, The detection position (10) is provided with a pipeline channel (22) on the lower mold (2) that communicates with the corresponding sink cavity (19). Each pipeline channel (22) is provided with a compensation pipe (11). The compensation pipe (11) is inserted into the annular cavity (21) through the corresponding pipeline channel (22) and communicates with the hollow sealing ring (9) relative to the corresponding detection position (10).

8. The high-vacuum die-casting mold for an engine crankcase according to claim 7, characterized in that, The top surface of the hollow sealing ring (9) is an upwardly convex arc surface, and the top of its cavity is also an upwardly convex arc surface.

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