Low-pressure casting mold for high-toughness lightweight valve body

Abstract

The invention relates to the technical field of low-pressure casting, and particularly discloses a high-toughness light-weight valve body low-pressure casting mold which comprises a bottom plate, a feeding port is formed in the bottom end of the bottom plate, an electric three-way valve is fixedly connected to the bottom end of the feeding port, a guide column is arranged at the top of the bottom plate, and a top plate is fixedly connected to the top end of the guide column. A lower mold is fixedly connected to the top end of the bottom plate, an upper mold is arranged at the top of the lower mold, a cooling reflux device is arranged at the top of the upper mold, a driving device cooling reflux pump carried on the upper mold can accelerate circulating flow of liquid in a lower mold cavity and an upper mold cavity, and the heat exchange effect is further enhanced. In the preheating stage, the system ingeniously utilizes heat energy of flowing metal liquid in the cavity to conduct uniform preheating treatment on the sand core, original sand core temperature field distribution is effectively improved, and the problem of shrinkage cavity defects caused by uneven die temperature fields during valve shell die casting is fundamentally solved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-pressure casting, and more particularly to a low-pressure casting mold for a high-strength, tough and lightweight valve body. Background Art

[0002] In modern manufacturing, casting is an important process for producing metal components, and low-pressure casting has been widely used in many fields due to its unique advantages.

[0003] Existing low-pressure casting applies low pressure in a closed crucible to make the molten metal smoothly fill from bottom to top. Compared with traditional gravity casting, it effectively reduces the gas entrapment phenomenon during the flow of the molten metal, improving the density and mechanical properties of the casting. Existing low-pressure casting molds mainly include a cavity part, a gating system, a cooling system, a demolding mechanism, a guiding mechanism, and a supporting and fixing structure. However, there are still the following deficiencies in existing low-pressure casting molds: 1. The structural design of the mold directly affects the filling speed, temperature distribution, and solidification process of the molten metal. Unreasonable mold design, layout of the cooling and preheating systems, insufficient alloy solidification shrinkage or feeding result in shrinkage cavities and porosity, especially significant in hot spots. For example, in the die casting of valve housings, due to uneven temperature field distribution in the original mold, the shrinkage cavity defect rate is over 30%, which may cause problems such as shrinkage cavities and deformation in the casting; 2. Upper and lower split molds are widely used in casting production due to their simple structural form. This type of mold divides the overall structure into an upper mold and a lower mold. Compared with the complex mold structure with four-sided splitting, it significantly reduces the number of parting surfaces and the components. However, when facing the casting requirement of a heavier valve body, the limitations of the upper and lower split molds gradually become prominent. Since the weight of the valve body is concentrated in the cavity part borne by the lower mold, after mold opening, the lower mold needs to independently bear the weight of the casting. Coupled with the adhesion force generated during the solidification of the molten metal during casting, it is difficult to separate the lower mold from the casting. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a low-pressure casting mold for a high-strength, tough and lightweight valve body to solve the problems existing in the above background art.

[0005] The present invention provides the following technical solution: a low-pressure casting mold for a high-strength, tough and lightweight valve body, including a bottom plate. An inlet is provided at the bottom end of the bottom plate, and an electric three-way valve is fixedly connected to the bottom end of the inlet. Guide columns are arranged on the top of the bottom plate, and a top plate is fixedly connected to the top ends of the guide columns. A lower mold is fixedly connected to the top of the bottom plate, an upper mold is arranged on the top of the lower mold, and a cooling and reflux device is arranged on the top of the upper mold. A lower template chamber is arranged inside the lower mold, and a lower heat equalizing plate is arranged on the inner side surface of the lower template chamber. An upper mold chamber is arranged inside the upper mold, and an upper heat equalizing plate is arranged on the inner side of the upper mold chamber. A telescopic bracket is arranged at the bottom of the upper mold. A lower mold is fixedly connected to the top of the bottom plate, and a lower template diversion pipe is opened at the junction of the bottom plate and the lower mold. A lower template chamber is opened inside the side surface of the lower mold, and staggered lower heat equalizing plates are fixedly connected to the inner side surface of the lower template chamber. There are four lower heat equalizing plates. A square groove is opened at the top of the side surface of the lower mold, and a lower mold feeding hole is opened at the top of the side surface of the lower mold. The two lower mold feeding holes are symmetrically arranged. A lower return pipe fixing seat with a hole in the middle is fixedly connected to the side surface of the lower mold. An annular groove is opened at the top of the lower return pipe fixing seat. Core plate guide rails are arranged in the inner cavity of the lower mold. There are four core plate guide rails. A core plate is arranged at the bottom of the inner cavity of the lower mold, and a telescopic bracket is arranged on the top of the core plate.

[0006] Further, hydraulic cylinders are arranged on the top of the bottom plate. The two hydraulic cylinders are fixedly connected to the diagonal positions of the bottom plate. An inlet and a reflux pipe orifice are opened on the bottom plate. The four guide columns are located at the four corners of the bottom plate.

[0007] Further, support bases are fixedly connected to the side surface of the core plate. There are two support bases. Guide blocks are arranged on the side surface of the core plate. There are four guide blocks. Telescopic brackets are arranged on the top of the support bases. There are two telescopic brackets. A spring base is arranged in the middle of the telescopic bracket. A support spring is arranged at the bottom of the spring base. A bracket limit column is arranged inside the telescopic bracket.

[0008] Further, ventilation holes are arranged on the top of the upper mold. An upper mold chamber is arranged inside the upper mold. An upper heat equalizing plate is fixedly connected to the inner side surface of the upper mold chamber. A square fixing block is fixedly connected to the bottom of the upper mold. An upper mold feeding hole is opened at the bottom of the upper mold. An upper return pipe fixing seat with a hole in the middle is fixedly connected to the side surface of the upper mold. An annular fixing block is fixedly connected to the bottom of the upper return pipe fixing seat.

[0009] Further, a top die guiding pipe is provided at the top of the top die, a gas-liquid conveying port is provided on the upper top surface of the top die, a core feeding port is provided on the lower top surface of the top die, guiding holes are provided at the four corner positions of the top die, a bracket upper fixing seat is provided at the bottom of the top die, and a hydraulic cylinder supporting seat is provided on the side surface of the top die. The two hydraulic cylinder supporting seats are arranged diagonally.

[0010] Further, the four upper heat plates are arranged staggeredly, there are two feeding holes on the top die, and the feeding holes on the top die and the feeding holes on the bottom die are arranged vertically and aligned.

[0011] Further, a cooling and reflux device is fixedly connected to the top of the top die. A gas-liquid pump is provided at the upper part of the cooling and reflux device. An upper die conduit is fixedly connected to the side surface of the gas-liquid pump. The gas-liquid pump is fixedly connected with a transverse reflux pipe. The transverse reflux pipe is fixedly connected with an upper reflux pipe. The lower end of the upper reflux pipe is fixedly connected with an upper reflux pipe fixing seat. A lower reflux pipe fixing seat is arranged at the lower end of the upper reflux pipe fixing seat. A lower reflux pipe is fixedly connected inside the lower reflux pipe fixing seat.

[0012] Further, a control motor is fixedly connected to the side surface of the electric three-way valve, and a coolant joint is fixedly connected to the bottom end of the electric three-way valve.

[0013] The technical effects and advantages of the present invention: 1. By constructing a lower template cavity and an upper die cavity structure inside the components of the bottom die and the top die, and respectively installing a lower heat plate and an upper heat plate assembly, the present invention greatly improves the heat exchange efficiency between the core and the internal liquid. During the heat transfer process, the cooling and reflux pump of the driving device mounted on the top die can accelerate the liquid circulation in the upper and lower template cavities, further enhancing the heat exchange effect. During the preheating stage, the system cleverly utilizes the heat energy of the flowing molten metal in the cavity to uniformly preheat the core, effectively improving the original core temperature field distribution, and fundamentally avoiding the shrinkage cavity defect problem caused by uneven die temperature field during valve housing die casting. After entering the cooling stage, the lower heat plate and the upper heat plate, relying on their high thermal conductivity, cause the core to cool down quickly, significantly accelerating the core temperature change rate, and finally achieving the goal of greatly shortening the casting cycle and improving production efficiency.

[0014] 2. The present invention innovatively provides a linkage mechanism telescopic bracket between the upper mold and the core bottom plate of the component. This design can ensure the efficient linkage between the upper mold of the component and the core bottom plate during the ascending process. The elastic component support spring configured on the side of the mechanism telescopic bracket can enable the telescopic bracket installed on the core bottom plate to be smoothly unfolded when there is no core load on the core bottom plate, providing convenient conditions for the placement of the core. At the same time, the limit structure bracket limit post set on the telescopic bracket can effectively limit the movement trajectory of the component core bottom plate, enabling it to move only within the internal space of the lower mold of the component. In addition, the positioning structure guide block on the component core bottom plate closely cooperates with the guide part core bottom plate guide rail, which can ensure the stability of the core bottom plate during the movement process and prevent the core from shifting during the descending process. This series of designs not only significantly improves the loading and unloading efficiency of the core, but also effectively ensures the quality stability of valve body casting.

[0015] 3. The present invention provides a switching device, an electric three-way valve, at the bottom of the component bottom plate. Through this device, the flow direction of the liquid flowing through the channel feed port can be flexibly controlled. In cooperation with the coordinated operation of the component cooling reflux pump, the free switching between two working modes of gas pumping and liquid pumping can be achieved. During the process of filling the core with molten metal, this system can quickly and efficiently pump out the excess molten metal in the cavity lower template chamber and the upper mold chamber; during the core cooling stage, it can significantly accelerate the circulation flow rate of the coolant and quickly discharge the coolant in the lower template chamber and the upper mold chamber cavity. Through the above functions, the time required for core preheating and cooling is effectively shortened, and the overall casting production efficiency is greatly improved. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the working stage of the present invention.

[0018] Figure 3 It is Figure 2 a schematic diagram of the half-sectional structure at B in

[0019] Figure 4 It is Figure 2 a schematic diagram of the quarter-sectional structure at B in

[0020] Figure 5 It is Figure 3 a schematic diagram of the structure at A in

[0021] Figure 6 It is Figure 4 a schematic diagram of the structure at C in

[0022] Figure 7 It is Figure 4 a schematic diagram of the structure at D in

[0023] The reference numerals are as follows: 1, bottom plate; 11, lower template diversion pipe; 12, feed inlet; 13, return pipe orifice; 14, hydraulic cylinder; 141, hydraulic cylinder support seat; 15, guide post; 2, electric three-way valve; 21, control motor; 22, coolant joint; 23, molten metal joint; 3, lower die; 31, lower template chamber; 32, lower return pipe fixing seat; 321, annular groove; 33, square groove; 34, lower die feeding hole; 35, lower heat equalizing plate; 36, core bottom plate; 361, support base; 362, guide block; 37, telescopic support; 371, spring base; 372, support limit post; 373, support spring; 38, core bottom plate guide rail; 4, upper die; 41, vent hole; 42, upper die chamber; 421, upper heat equalizing plate; 422, upper die feeding hole; 423, square fixing block; 43, upper die diversion pipe; 44, upper return pipe fixing seat; 441, annular fixing block; 45, gas-liquid delivery port; 46, core feeding port; 47, guide hole; 48, upper fixing seat for support; 5, cooling and return device; 51, gas-liquid pump; 52, upper die conduit; 53, horizontal return pipe; 54, upper return pipe; 55, lower return pipe; 6, top plate. Detailed implementation manners

[0024] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the accompanying drawings in the present invention. Additionally, the forms of each structure described in the following implementation manners are merely examples. The low-pressure casting mold for a high-strength, high-toughness, and lightweight valve body related to the present invention is not limited to the structures described in the following implementation manners. All other implementation manners obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0025] Refer to Figure 1 、 Figure 2 and Figure 3, the present invention provides a low-pressure casting mold for a high-strength, tough and lightweight valve body, including a bottom plate 1. At the bottom end of the bottom plate 1, there is a feed port 12, and a motorized three-way valve 2 is fixedly connected to the bottom end of the feed port 12. At the top of the bottom plate 1, there are guide columns 15, and at the top ends of the guide columns 15, there is a top plate 6 fixedly connected. At the top end of the bottom plate 1, a lower mold 3 is fixedly connected. At the top of the lower mold 3, there is an upper mold 4. At the top of the upper mold 4, there is a cooling and reflux device 5. Inside the lower mold 3, there is a lower template chamber 31, and on the inner side of the lower template chamber 31, there is a lower heat sink plate 35. Inside the upper mold 4, there is an upper mold chamber 42, and on the inner side of the upper mold chamber 42, there is an upper heat sink plate 421. At the bottom of the upper mold 4, there is a telescopic support 37. At the top of the bottom plate 1, a lower mold 3 is fixedly connected. At the junction of the bottom plate 1 and the lower mold 3, there is a lower template diversion pipe 11. Inside the side of the lower mold 3, there is a lower template chamber 31, and on the inner side of the lower template chamber 31, there are staggeredly arranged lower heat sink plates 35. There are four lower heat sink plates 35. At the top side of the lower mold 3, there is a square groove 33, and at the top side of the lower mold 3, there are lower mold feed holes 34. The two lower mold feed holes 34 are symmetrically arranged. At the side of the lower mold 3, there is a lower return pipe fixing seat 32 with a hole in the middle. At the top of the lower return pipe fixing seat 32, there is an annular groove 321. Inside the inner cavity of the lower mold 3, there are four core bottom plate guide rails 38. At the bottom of the inner cavity of the lower mold 3, there is a core bottom plate 36. At the top of the core bottom plate 36, there is a telescopic support 37.

[0026] Referring to Figure 2 and Figure 3 , at the top of the bottom plate 1, there are hydraulic cylinders 14. The two hydraulic cylinders 14 are fixedly connected at the diagonal positions of the bottom plate 1. On the bottom plate 1, there are a feed port 12 and a reflux pipe orifice 13. The four guide columns 15 are located at the four corners of the bottom plate 1.

[0027] Referring to Figure 3 and Figure 6 , on the side of the core bottom plate 36, there are two support base seats 361 fixedly connected. On the side of the core bottom plate 36, there are four guide blocks 362. At the top of the support base seats 361, there are two telescopic supports 37. In the middle of the telescopic supports 37, there is a spring base 371. At the bottom of the spring base 371, there is a support spring 373. Inside the telescopic supports 37, there are support limit columns 372.

[0028] A cooperative control mechanism is formed between the internal structure of the telescopic support 37 and the core bottom plate 36 to ensure the stable operation of the core during the entire casting process. When the core bottom plate 36 is in the no-load state, the support springs 373 between the spring bases 371 release elastic potential energy, pushing the telescopic support 37 to expand smoothly. This elastic support system can not only overcome the influence of gravity but also eliminate structural gaps through pre-tightening force to ensure the motion accuracy during no-load. The support limit posts 372, as key safety guarantee components, precisely control the maximum expansion stroke of the telescopic support 37 through mechanical limits. When the preset position is reached, the limit posts 372 form a rigid stop with the support structure to prevent the core bottom plate 36 from detaching from the lower mold 3 due to excessive displacement, effectively avoiding equipment failures and safety hazards.

[0029] During the dynamic operation, the guide blocks 362 on the core bottom plate 36 and the core bottom plate guide rails 38 in the lower mold 3 form a precision sliding pair. This line-contact guiding structure can not only provide sufficient lateral support force but also reduce the friction coefficient through surface hardening treatment, enabling the core bottom plate 36 to maintain ideal motion accuracy when carrying the core.

[0030] Refer to Figure 3 and Figure 5 , there are vent holes 41 provided at the top of the upper mold 4, an upper mold cavity 42 is arranged inside the upper mold 4, an upper heat plate 421 is fixedly connected to the inner side surface of the upper mold cavity 42, a square fixing block 423 is fixedly connected to the bottom of the upper mold 4, an upper mold feeding hole 422 is opened at the bottom of the upper mold 4, an upper return pipe fixing seat 44 with a hole inside is fixedly connected to the side surface of the upper mold 4, and an annular fixing block 441 is fixedly connected to the bottom of the upper return pipe fixing seat 44.

[0031] Refer to Figure 3 , an upper mold diversion pipe 43 is opened at the top of the upper mold 4, a gas-liquid delivery port 45 is opened on the upper top surface of the upper mold 4, a core feeding port 46 is opened on the lower top surface of the upper mold 4, guiding holes 47 are opened at the four corner positions of the upper mold 4, a support upper fixing seat 48 is arranged at the bottom of the upper mold 4, and hydraulic cylinder support seats 141 are arranged on the side surface of the upper mold 4, and the two hydraulic cylinder support seats 141 are arranged diagonally.

[0032] Refer to Figure 3 , the four upper heat plates 421 are arranged staggeredly, there are two upper mold feeding holes 422, and the upper mold feeding holes 422 are arranged vertically aligned with the lower mold feeding holes 34.

[0033] Through the interleaved heat pipes 421, efficient heat exchange between the liquid and the sand core in the lower template chamber 31 and the upper template chamber 42 can be achieved. This special interleaved layout forms a tortuous heat exchange path, greatly increasing the heat exchange area and contact time, enabling heat to be more fully transferred from the high-temperature area to the low-temperature area. The heat pipes 421 are made of high thermal conductivity materials, capable of quickly absorbing and releasing heat, further enhancing the heat conduction efficiency.

[0034] During the casting process, after the high-temperature molten metal is injected into the mold, the heat pipes 421 quickly conduct the heat out of the liquid and transfer it to the relatively cooler sand core, enabling the molten metal to cool and solidify faster. At the same time, the uniform distribution of the heat pipes 421 ensures the uniformity of the temperature distribution throughout the cavity, avoiding casting defects caused by local overheating or overcooling. This efficient heat exchange mechanism not only shortens the production cycle of a single casting but also improves the quality and consistency of the castings, thus significantly enhancing the overall working efficiency. In addition, by precisely controlling the heat exchange process, the microstructure of the castings can be optimized, improving their mechanical properties and service life.

[0035] Refer to Figure 4 and Figure 5 As shown in

[0036] The cooling and reflux device 5 can quickly drive the supply and discharge of the liquid in the lower template chamber 31 and the upper template chamber 42. The specific process is as follows: When the sand core is filled with molten metal, as the pressure in the crucible decreases, the excess molten metal will flow back to the crucible. Due to the structure of the inner walls of the lower template chamber 31 and the upper template chamber 42, the reflux rate of the molten metal is relatively slow. At this time, the pumping function of the gas-liquid pump 52 can be utilized to pump gas into the lower template chamber 31 and the upper template chamber 42 through the gas-liquid delivery port 45 to accelerate the discharge of the internal liquid, thereby shortening the working time and improving the working efficiency.

[0037] Refer to Figure 7, a control motor 21 is fixedly connected to the side of the electric three-way valve 2, and a coolant joint 22 is fixedly connected to the bottom end of the electric three-way valve 2. The replacement and discharge of the liquid inside the lower template chamber 31 and the upper template chamber 42 are realized through the electric three-way valve 2. Specifically, through the action of the control motor 21, the metal liquid joint 23 of the electric three-way valve 2 is communicated with the feed port 12, so as to supply metal liquid to the lower template chamber 31 and the upper template chamber 42 and preheat the mold with the metal liquid. The temperature of the metal liquid is fully utilized to make the temperature field distribution in the mold uniform, effectively improving the temperature field distribution of the original sand core and avoiding the shrinkage cavity defect problem caused by uneven mold temperature field during valve housing die casting from the root cause.

[0038] The working principle of the present invention: In the preparation stage, the hydraulic cylinder support seat 141 on the upper mold 4 is lifted by the hydraulic cylinder 14 provided on the bottom plate 1, so that the upper mold 4 rises and drives the sand core bottom plate 36 to rise under the action of the telescopic bracket 37. Through the interaction between the sand core bottom plate guide rail 38 provided inside the lower mold 3 and the guide block 362 on the sand core bottom plate 36, the sand core bottom plate 36 can only move up and down smoothly, avoiding the offset of the sand core caused by the offset of the sand core bottom plate 36 during the movement process. When the upper mold 4 rises to the highest position, the hydraulic cylinder 14 stops working. At this time, under the action of the support spring 373, the telescopic bracket 37 expands and leaves enough space to place the sand core, and it is also convenient to take the sand core. Through the limiting action of the bracket limiting column 372 provided in the middle of the telescopic bracket 37, the telescopic bracket 37 expands at the pre-set position. At this time, the sand core is placed on the top of the sand core bottom plate 36. Through the work of the hydraulic cylinder 14 provided on the bottom plate 1, the upper mold 4 descends to the combined position with the lower mold 3. Through the cooperation between the square fixing block 423 provided on the upper mold 4 and the square groove 33 provided on the lower mold 3, the lower mold 3 and the upper mold 4 are closely fitted. Through the contact between the sand core bottom plate 36 and the bottom of the lower mold 3, the support spring 373 in the lower mold 37 is compressed, so as to expand the telescopic bracket 37 at the end of the work. Through the control motor 21 provided on the electric three-way valve 2, the metal liquid joint 23 end of the electric three-way valve 2 is connected to the feed port 12, and at the same time, the coolant joint 22 end is in a closed state.

[0039] In the preheating stage, under the action of external pressure, the high-temperature molten metal enters the lower die 3 through the molten metal joint 23 and the coolant joint 22. The molten metal flows into the interior of the lower template chamber 31 through the lower template diversion pipe 11. The molten metal accumulates continuously inside the lower template chamber 31, and at the same time, the heat is conducted to the inner cavity of the lower die 3 through the lower heat plate 35 arranged on the inner wall of the lower template chamber 31, so that the temperature of the inner cavity of the lower die 3 continuously rises to the same as that of the molten metal. Through the lower die feeding hole 34 arranged at the top of the lower die 3, the molten metal flows into the upper die cavity 42 arranged inside the upper die 4. The heat is conducted to the inner cavity of the upper die 4 through the upper heat plate 421 arranged on the inner wall of the upper die cavity 42, so that the temperature of the inner cavity of the upper die 4 continuously rises to the same as that of the molten metal, making the distribution of the original die temperature field uniform and avoiding the shrinkage cavity defect caused by the uneven distribution of the temperature field in the original die during the valve housing die casting.

[0040] When the molten metal fills the inside of the upper mold cavity 42 during the cooling stage, through the upper mold diversion pipe 43 provided at the top of the upper mold 4, the molten metal flows into the inside of the sand core through the sand core feeding port 46. When the inside of the sand core is filled with molten metal and passes through the gas-liquid delivery port 45, the cooling and reflux device 5 provided on the upper mold 4 is activated. At the same time, the external pressure stops, and the molten metal no longer enters the mold. Gas is pumped into the upper mold cavity 42 and the lower template cavity 31 through the gas-liquid delivery port 45. Under the action of the air pressure, the internal molten metal flows back to the crucible through the feeding port 12. When the electric three-way valve 2 detects that there is no molten metal at the molten metal joint 23, the cooling and reflux device 5 stops operating. And by controlling the motor 21 to drive the electric three-way valve 2, the feeding port 12 is connected to the coolant joint 22. The cooling and reflux device 5 provided on the upper mold 4 is started again, and coolant is pumped into the upper mold cavity 42 and the lower template cavity 31 through the coolant joint 22 and the feeding port 12. The molten metal in the sand core is cooled by the upper heat plate 421 and the lower heat plate 35 provided on the inner walls of the upper mold cavity 42 and the lower template cavity 31. The coolant flows into the horizontal reflux pipe 53 and the upper reflux pipe 54 through the cooling and reflux device 5 provided on the upper mold 4. Through the upper reflux pipe fixing seat 44 provided on the upper mold 4 and the lower reflux pipe fixing seat 32 provided on the lower mold 3, wherein a ring-shaped fixing block 441 is provided at the bottom of the upper reflux pipe fixing seat 44 and a ring-shaped groove 321 is provided at the top of the lower reflux pipe fixing seat 32. Through the mutual cooperation of the ring-shaped fixing block 441 and the lower reflux pipe fixing seat 32, the upper reflux pipe fixing seat 44 and the lower reflux pipe fixing seat 32 are tightly combined during the casting stage, and the coolant for cooling the lower mold 3 and the upper mold 4 is guided to flow back to the storage tank through the reflux pipe orifice 13. By continuously flowing the coolant inside the upper mold 4 and the lower mold 3 and taking away the heat inside the sand core, the sand core is sufficiently cooled. When the cooling is completed, the pumping of the coolant is stopped through the cooling and reflux device 5 provided on the upper mold 4, so that the coolant inside the lower mold 3 and the upper mold 4 flows back to the storage tank under the action of gravity. Due to the structural characteristics, the coolant inside the upper reflux pipe 54 and the lower reflux pipe 55 is drained before the inside of the lower mold 3 and the upper mold 4. During the reflux process, the cooling and reflux device 5 starts the pumping gas state, and gas is filled into the lower mold 3 and the upper mold 4 through the gas-liquid delivery port 45 provided on the upper mold 4, accelerating the discharge of the internal coolant, shortening the working time, and improving the working efficiency.

[0041] At the end of casting, the upper die 4 and the lower die 3 are separated by the hydraulic cylinder 14 provided on the bottom plate 1. The telescopic support 37 moves upward to lift the core bottom plate 36 through the fixing seat 48 on the support provided on the upper die 4. Under the combined action of the elasticity of the support spring 373 provided inside the telescopic support 37 and gravity, the core bottom plate 36 drives the core to move upward. When the upper die 4 rises to the maximum position, the telescopic support 37 only expands to the set position through the limiting action of the support limiting column 372 provided on the telescopic support 37, preventing the telescopic support 37 from driving the core bottom plate 36 away from the lower die 3. At this time, the core is at the same height as the top of the lower die 3, facilitating the removal of the core and avoiding the difficulty in removing the core caused by its excessive weight.

[0042] Secondly, in the accompanying drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. Other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other. Finally, the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A low-pressure casting mold for a high-strength, tough and lightweight valve body, comprising a bottom plate (1), characterized in that: The bottom end of the bottom plate (1) is provided with a feed inlet (12), the bottom end of the feed inlet (12) is fixedly connected with an electric three-way valve (2), the top of the bottom plate (1) is provided with guide posts (15), the top ends of the guide posts (15) are fixedly connected with a top plate (6), the top end of the bottom plate (1) is fixedly connected with a lower mold (3), a upper mold (4) is arranged on the top of the lower mold (3), a cooling and reflux device (5) is arranged on the top of the upper mold (4), a lower template chamber (31) is arranged inside the lower mold (3), a lower heat sink plate (35) is arranged on the inner side surface of the lower template chamber (31), an upper mold chamber (42) is arranged inside the upper mold (4), an upper heat sink plate (421) is arranged on the inner side of the upper mold chamber (42), a telescopic bracket (37) is arranged at the bottom of the upper mold (4), the top of the bottom plate (1) is fixedly connected with a lower mold (3), a lower template diversion pipe (11) is opened at the junction of the bottom plate (1) and the lower mold (3), a lower template chamber (31) is opened inside the side surface of the lower mold (3), the inner side surface of the lower template chamber (31) is fixedly connected with staggered lower heat sink plates (35), there are four lower heat sink plates (35), a square groove (33) is opened at the top of the side surface of the lower mold (3), a lower mold feed hole (34) is opened at the top of the side surface of the lower mold (3), the two lower mold feed holes (34) are symmetrically arranged, the side of the lower mold (3) is fixedly connected with a lower reflux pipe fixing seat (32) with a hole in the middle, an annular groove (321) is opened at the top of the lower reflux pipe fixing seat (32), a core bottom plate guide rail (38) is opened in the inner cavity of the lower mold (3), there are four core bottom plate guide rails (38), a core bottom plate (36) is arranged at the bottom of the inner cavity of the lower mold (3), a telescopic bracket (37) is arranged on the top of the core bottom plate (36).

2. The low-pressure casting die for a high-strength, tough and lightweight valve body according to claim 1, characterized in that: A hydraulic cylinder (14) is arranged on the top of the bottom plate (1), the two hydraulic cylinders (14) are fixedly connected at the diagonal positions of the bottom plate (1), a feed inlet (12) and a reflux pipe orifice (13) are opened on the bottom plate (1), and the four guide posts (15) are located at the four corners of the bottom plate (1).

3. The low-pressure casting mold for a high-strength, tough and lightweight valve body according to claim 2, characterized in that: A bracket base (361) is fixedly connected to the side surface of the core bottom plate (36), there are two bracket bases (361), a guide block (362) is arranged on the side surface of the core bottom plate (36), there are four guide blocks (362), a telescopic bracket (37) is arranged on the top of the bracket base (361), there are two telescopic brackets (37), a spring base (371) is arranged in the middle of the telescopic bracket (37), a support spring (373) is arranged at the bottom of the spring base (371), and a bracket limit post (372) is arranged inside the telescopic bracket (37).

4. The low-pressure casting mold for a high-strength, tough and lightweight valve body according to claim 1, characterized in that: The top of the upper mold (4) is provided with a vent hole (41). The inside of the upper mold (4) is provided with an upper mold cavity (42). The inner side of the upper mold cavity (42) is fixedly connected with an upper heat sink plate (421). The bottom of the upper mold (4) is fixedly connected with a square fixing block (423). The bottom of the upper mold (4) is provided with an upper mold feeding hole (422). The side of the upper mold (4) is fixedly connected with an upper return pipe fixing seat (44) with a hole inside. The bottom of the upper return pipe fixing seat (44) is fixedly connected with an annular fixing block (441).

5. The low-pressure casting mold for a high-strength, tough and lightweight valve body according to claim 1, characterized in that: The top of the upper mold (4) is provided with an upper mold guide pipe (43). The upper top surface of the upper mold (4) is provided with a gas-liquid transfer port (45). The lower top surface of the upper mold (4) is provided with a core sand feeding port (46). The four corners of the upper mold (4) are provided with guide holes (47). The bottom of the upper mold (4) is provided with a bracket upper fixing seat (48). The side of the upper mold (4) is provided with a hydraulic cylinder support seat (141). The two hydraulic cylinder support seats (141) are arranged diagonally.

6. The high-strength, tough and lightweight valve body low-pressure casting mold according to claim 4, characterized in that: The four upper heat sink plates (421) are arranged staggeredly. There are two upper mold feeding holes (422). The upper mold feeding holes (422) and the lower mold feeding holes (34) are arranged vertically and aligned.

7. The low-pressure casting die for a high-strength, tough and lightweight valve body according to claim 1, characterized in that: The top of the upper mold (4) is fixedly connected with a cooling and reflux device (5). The upper part of the cooling and reflux device (5) is provided with a gas-liquid pump (51). The side of the gas-liquid pump (51) is fixedly connected with an upper mold conduit (52). The gas-liquid pump (51) is fixedly connected with a horizontal return pipe (53). The horizontal return pipe (53) is fixedly connected with an upper return pipe (54). The lower end of the upper return pipe (54) is fixedly connected with an upper return pipe fixing seat (44). The lower end of the upper return pipe fixing seat (44) is provided with a lower return pipe fixing seat (32). The inside of the lower return pipe fixing seat (32) is fixedly connected with a lower return pipe (55).

8. The high-strength, tough and lightweight valve body low-pressure casting die according to claim 1, characterized in that: The side of the electric three-way valve (2) is fixedly connected with a control motor (21). The bottom end of the electric three-way valve (2) is fixedly connected with a coolant connector (22).

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