Core-pulling low-pressure die and forming method

Abstract

The invention provides a core-pulling low-pressure die and a forming method, relates to the field of low-pressure dies, and aims to solve the problem that aluminum liquid overflows and adheres to aluminum due to a matching gap between a pulling core and a die of an existing core-pulling low-pressure die. The matching gap between an upper die and a lower die at the core-pulling position is eliminated by arranging a guide sleeve, and the guide sleeve and the lower die are integrally formed or sealed in an embedded mode; the loose core only forms a single matching relation with the integral structure of the lower die, a matching gap can be strictly controlled through precision machining, an extra gap generated by splicing of the upper die and the lower die does not exist, the invasion path of molten aluminum is blocked from the structural level, and the effect that aluminum is not prone to entering is achieved. The self-tightening characteristic of inclined plane attachment is utilized for conical surface sealing, even if the mold is slightly thermally deformed at a high temperature, the loose core and the conical surface of the guide sleeve can still be tightly attached through micro-adjustment of the contact surface, and the path that molten aluminum enters the sliding hole is effectively blocked.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of low-pressure die, in particular to a core-pulling low-pressure die and a forming method. BACKGROUND

[0002] In the prior art, the core-pulling low-pressure die is mainly composed of an upper die, a lower die and a core-pulling mechanism. The upper die and the lower die are combined to form a forming cavity. The core-pulling mechanism can move in the die to realize the forming of a specific structure. In the production process, the position of the core-pulling mechanism is usually close to the gate. A slot is opened on the die at the corresponding position to meet the installation and movement requirements of the core-pulling mechanism. There is a matching gap between the core-pulling mechanism and the die. The position limiting of the core-pulling mechanism is usually a fixed structure, which cannot be adjusted according to the production situation.

[0003] However, the prior art has many problems. On the one hand, because the core-pulling mechanism is close to the gate, the die is prone to thermal deformation under high temperature, which causes the gap between the core-pulling mechanism and the die to increase. The aluminum liquid is easy to overflow into the gap. Long-term production will cause the core-pulling mechanism to stick to aluminum, which will destroy the normal production rhythm. The wear and tear caused by long-term production will cause the position of the core-pulling mechanism to deviate, which will cause the wall thickness of the product to be unstable. In addition, the local strength of the die will decrease due to the slot for the core-pulling mechanism, which will easily cause cracking. Although the conventional methods such as increasing cooling or improving machining precision can alleviate the problems of thermal deformation and gap to some extent, they cannot fundamentally solve the problem of aluminum liquid overflow sealing. The fixed limiting structure also cannot cope with the size deviation caused by long-term wear and tear. The strength problem of the die after slotting also lacks effective solutions. SUMMARY

[0004] The purpose of the present application is to solve the defects in the prior art. The core-pulling low-pressure die and the forming method are provided. By setting a guide sleeve, the matching gap between the upper die and the lower die at the position of the core-pulling mechanism is eliminated. The guide sleeve is integrally formed with the lower die or embedded in the lower die. The core-pulling mechanism only forms a single matching relationship with the overall structure of the lower die. The matching gap can be strictly controlled through precise machining. There is no additional gap caused by the splicing of the upper die and the lower die. From the structural level, the path of aluminum liquid invasion is blocked, and the effect of not easy to enter aluminum is achieved.

[0005] The first purpose of the present application is to provide a core-pulling low-pressure die, which adopts the following scheme: The core-pulling low-pressure die comprises an upper die, a lower die and a core-pulling mechanism. The upper die and the lower die are combined to form a forming cavity. The lower die is provided with a guide sleeve. The guide sleeve is provided with a sliding hole for the core-pulling mechanism to pass through and form a sliding fit. The outer part of the guide sleeve is attached to the corresponding position of the upper die. One end of the sliding hole is open and communicates with the forming cavity. A conical surface is formed at the position of the one end opening. The other end opening extends to the outer wall of the lower die. One end of the core-pulling mechanism serves as a feature end which can be inserted into or withdrawn from the forming cavity. The other end is a driving end which is subjected to external force. When the feature end is inserted into the forming cavity, the outer peripheral wall of the core-pulling mechanism is attached to the conical surface to form a conical surface seal, so as to isolate the sliding hole and the forming cavity.

[0006] Further, the guide sleeve is integrally formed with the lower mold body or is sealingly embedded in the lower mold, and the diameter of the tapered surface gradually increases in the direction away from the molding cavity along the sliding hole.

[0007] Further, the segment of the core-pulling connecting molding end is provided with a tapered shaft segment capable of being sealingly attached to the tapered surface.

[0008] Further, the core-pulling is internally provided with a water cooling channel, and the opening of the water cooling channel is arranged at the segment of the core-pulling outside the sliding hole and is connected to a water cooling assembly.

[0009] Further, the driving end of the core-pulling is connected to a first core-pulling assembly, the joint of the water cooling assembly is connected to the opening of the water cooling channel, and the first core-pulling assembly drives the core-pulling and the water cooling joint to slide along the sliding hole.

[0010] Further, a wear-resistant block is arranged between the core-pulling assembly and the lower mold, and wear-resistant blocks of different thicknesses can be alternatively installed to control the gap between the core-pulling assembly and the lower mold, so as to control the length of the core-pulling into the molding cavity.

[0011] Further, a second steel core is further included, the second steel core is slidingly connected to the lower mold, one end of the second steel core faces the core-pulling and extends into the molding cavity, and a water cooling channel is arranged in the second steel core.

[0012] Further, the end of the second steel core away from the molding cavity extends to the outside of the lower mold and is connected to a second core-pulling assembly, so as to drive the second steel core to extend into or withdraw from the molding cavity.

[0013] The second object of the present application is to provide a molding method of a core-pulling low-pressure mold, which utilizes the core-pulling low-pressure mold provided in the first object, and the method comprises the following steps: The upper mold is buckled with the lower mold to form a cavity for molding, the outer part of the guide sleeve of the lower mold is attached to the corresponding position of the upper mold to ensure overall sealing; The core-pulling is inserted into the other end opening of the sliding hole of the outer wall of the lower mold, so that the feature end of the core-pulling moves towards the molding cavity; when the feature end extends into the molding cavity, the outer peripheral wall of the core-pulling is tightly attached to the tapered surface at the opening of the sliding hole to form a tapered surface sealing, so as to completely isolate the sliding hole from the molding cavity; The raw material is injected into the molding cavity to form the required workpiece by using the mold cavity, and the tapered surface sealing prevents the raw material from entering the sliding hole to cause material sticking or material running; After the molding is completed, the core-pulling is withdrawn from the molding cavity by applying an external force to the driving end, the feature end exits the molding cavity, and the tapered surface sealing is released; the upper mold is separated from the lower mold, and the molded product is taken out; The above steps of mold buckling, core-pulling positioning, molding, mold opening and product taking are repeated to realize continuous production.

[0014] Further, the core-pulling is cooled by the water cooling channel inside the core-pulling.

[0015] Compared with the prior art, the application has the advantages and positive effects that: In view of the problem of aluminum liquid overflow and aluminum sticking caused by the core-pulling and mold gap of the current core-pulling low-pressure mold, the guiding sleeve is arranged to eliminate the gap between the upper mold and the lower mold at the core-pulling position, the guiding sleeve is integrally formed with the lower mold or embedded in the lower mold, the core-pulling only forms a single fitting relationship with the overall structure of the lower mold, the fitting gap can be strictly controlled through precision machining, and there is no additional gap caused by the splicing of the upper mold and the lower mold, thereby blocking the path of aluminum liquid invasion from the structural level and realizing the effect of not easy to enter aluminum. The conical surface sealing utilizes the self-tightening characteristics of the inclined surface fitting, and even if the mold slightly deforms at high temperature, the conical surface fitting of the core-pulling and the guiding sleeve can still be closely fitted through the slight adjustment of the contact surface, thereby effectively blocking the path of the aluminum liquid into the sliding hole.

[0016] A wear-resistant block is arranged between the core-pulling assembly and the lower mold, and a plurality of wear-resistant blocks with different thickness specifications can be replaced and installed to control the gap between the core-pulling assembly and the lower mold, thereby controlling the length of the core-pulling into the forming cavity, solving the problem of position deviation caused by core-pulling wear in long-term production, compensating for the size deviation by simply replacing the wear-resistant block, ensuring the consistency of the product wall thickness, and avoiding waste caused by inaccurate core-pulling position. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description, make up the disclosure of the application. The illustrative embodiments of the application described herein and their descriptions serve to explain the application. They are not intended to limit the application in any manner.

[0018] Figure 1 is a schematic view of a core-pulling low-pressure mold in one or more embodiments of the application.

[0019] Figure 2 is a schematic view of a cylinder liner and the distribution of strain gauges thereon in one or more embodiments of the application.

[0020] 1, core-pulling; 2, guiding sleeve; 3, wear-resistant block; 4, lower mold; 5, first core-pulling assembly; 6, water cooling assembly; 7, conical surface sealing; 8, second steel core; 9, second core-pulling assembly; 10, forming gap; 11, forming cavity; 12, water cooling channel. DETAILED DESCRIPTION

[0021] Embodiment 1 In one typical embodiment of the application, as shown in Figures 1-2 , a core-pulling low-pressure mold is given.

[0022] The existing core 1 low-pressure mold causes the aluminum liquid overflow sticking aluminum problem due to the core 1 and the mold gap, and the derived problems such as production rhythm interruption and unstable product quality caused thereby. Under high-temperature production conditions, the gap is generated due to thermal deformation of the core 1 and the mold matching part, causing the aluminum liquid to invade the gap to cause the core 1 to stick aluminum, thereby destroying the production continuity. Based on this, the embodiment provides a core 1 low-pressure mold, and the taper sealing 7 utilizes the self-tightening characteristics of the inclined surface fitting. Even if the mold slightly deforms under high temperature, the taper fitting of the core 1 and the guide sleeve 2 can still be closely fitted through the slight adjustment of the contact surface, effectively blocking the path of the aluminum liquid into the sliding hole.

[0023] As shown in Figure 1 and Figure 2 , the core 1 low-pressure mold includes an upper mold, a lower mold 4, and a core 1. The upper mold and the lower mold 4 are buckled to form a forming cavity 11. The lower mold 4 is provided with a separate guide sleeve 2. The inner sliding hole of the guide sleeve 2 is provided for the core 1 to pass through and form a sliding fit. The sliding hole is communicated with the forming cavity 11. The taper is machined at the opening of the end of the sliding hole close to the forming cavity 11. One end of the core 1 is a characteristic end capable of exploring or withdrawing from the forming cavity 11. The other end is a driving end subjected to external force. When the characteristic end explores into the forming cavity 11, the outer peripheral wall of the core 1 is fitted with the taper to form a taper sealing 7, so as to isolate the sliding hole and the forming cavity 11.

[0024] The taper sealing 7 utilizes the self-tightening characteristics of the inclined surface fitting. Even if the mold slightly deforms under high temperature, the taper fitting of the core 1 and the guide sleeve 2 can still be closely fitted through the slight adjustment of the contact surface, effectively blocking the path of the aluminum liquid into the sliding hole. Compared with the linear gap formed by the direct fitting of the core 1 and the mold in the prior art, the sealing of the taper sealing 7 under the thermal deformation working condition is more reliable. The aluminum liquid overflow into the gap of the core 1 is avoided from the root, thereby preventing the core 1 from sticking aluminum.

[0025] Through the application of the taper sealing 7 structure, the hidden danger of the aluminum liquid invading the gap of the core 1 is directly eliminated. The core 1 sticking aluminum problem is fundamentally solved. The mold can maintain stable production rhythm and reduce downtime maintenance due to cleaning of stuck aluminum. At the same time, the isolation of the sliding hole and the forming cavity 11 avoids the core 1 from being stuck or the abrasion from being intensified due to the solidification of the aluminum liquid in the gap, thereby prolonging the service life of the core 1.

[0026] The guide sleeve 2 is arranged on the lower mold 4 and can cooperate with the lower mold 4 to match the upper mold. There is no gap between the guide sleeve 2 and the lower mold 4. The structure integrates the movement space of the core 1 as part of the lower mold 4 body. The core 1 completes the telescopic sliding in the sliding hole, which fundamentally changes the mode of the core 1 and the upper mold and the lower mold 4 being matched in the traditional mold.

[0027] By setting the guide sleeve 2, the mating gap of the upper die and the lower die 4 at the position of the core-pulling 1 is eliminated. In the traditional structure, the core-pulling 1 needs to pass through the splicing area of the upper and lower dies 4, and there is inevitably an assembly gap, and the high-temperature aluminum liquid is extremely easy to penetrate into the movement space of the core-pulling 1 along the gap; and in the embodiment, the guide sleeve 2 is integrally formed with the lower die 4 or embedded in sealing, and the core-pulling 1 only forms a single mating relationship with the overall structure of the lower die 4, the mating gap can be strictly controlled through precision machining, and there is no additional gap caused by the splicing of the upper die and the lower die 4, which blocks the path of aluminum liquid invasion from the structural level, and realizes the effect of not easy to enter aluminum.

[0028] At the same time, the overall guide sleeve 2 enhances the structural integrity of the lower die 4 in the core-pulling 1 area. The split slot opened for the installation of the core-pulling 1 in the traditional mold will weaken the local strength, and the overall tunnel design disperses stress through continuous structural transition, reduces the strength reduction problem caused by slotting of the mold, reduces the cracking risk under the high-temperature and high-pressure production environment, and further guarantees the stability of the core-pulling 1 mating gap. The independent setting of the guide sleeve 2 forms structural reinforcement to the slotting area of the lower die 4, indirectly alleviates the problem of insufficient local strength of the mold, and further guarantees the production stability.

[0029] As shown in Figure 1 and Figure 2 , the guide sleeve 2 and the lower die 4 adopt the integrally formed or sealing embedded mode, which ensures the connection strength and sealing performance of the guide sleeve 2 and the main body of the lower die 4, and avoids aluminum liquid leakage caused by assembly gap. The diameter of the taper surface gradually increases in the direction away from the forming cavity 11 along the axis of the sliding hole, and this structure forms a deeper and tighter trend when matched with the core-pulling 1. When the feature end of the core-pulling 1 penetrates into the forming cavity 11, the fitting pressure between the taper surface and the outer peripheral wall of the core-pulling 1 gradually increases with the increase of the insertion depth, which further enhances the sealing effect, especially in a high-temperature environment, the sealing reliability can be maintained through a small amount of structural compensation.

[0030] The segment of the core-pulling 1 connecting the forming end is provided with a tapered shaft segment, the taper of which matches the taper surface of the guide sleeve 2, so that the contact area is larger and the fit is tighter, and the stability of the sealing is improved.

[0031] The water cooling channel 12 inside the core-pulling 1 directly cools the core-pulling 1, reduces the heat conduction of the high-temperature aluminum liquid to the core-pulling 1, and reduces the size change of the core-pulling 1 caused by thermal expansion, so as to maintain the fitting precision of the tapered shaft segment and the taper surface; at the same time, the water cooling system reduces the surface temperature of the core-pulling 1, reduces the adhesion tendency of the aluminum liquid on the surface of the core-pulling 1, and forms a double anti-aluminum adhesion protection with the taper surface sealing 7.

[0032] In this embodiment, the core 1 is made of heat-treated die steel and the hardness is controlled in the range of HRC38-42. This material selection takes into account both structural strength and use characteristics. This hardness range makes the core 1 have sufficient wear resistance to resist long-term sliding friction, and avoids the increase in brittleness caused by excessive hardness, and can adapt to the stress impact caused by frequent expansion and temperature changes in the production process, providing a basic material guarantee for the stable work of the core 1.

[0033] The central water cooling channel 12 solves the problem of dimensional stability in high temperature environment. In the production process, the core 1 directly contacts the high temperature aluminum liquid and is easy to expand due to heating. If the expansion amount exceeds the design range, it will cause the core 1 and the guide sleeve 2 to have an abnormal fit clearance, which may cause jamming if too small, or damage the sealing effect if too large. The water cooling channel 12 removes heat from the core 1 through continuously circulating cooling liquid, effectively controls the temperature rise, thereby reducing the thermal expansion amount, ensuring that the size of the core 1 always maintains within the design tolerance range, which not only ensures the reliability of the tapered surface seal 7 between the core 1 and the guide sleeve 2, but also avoids the movement being blocked due to excessive expansion, thereby providing a stable temperature environment guarantee for the precise expansion and sealing performance of the core 1.

[0034] As shown in Figure 1 and Figure 2 , the driving end of the core 1 is connected with the first core assembly 5, and the joint of the water cooling assembly 6 is connected to the opening of the water cooling channel 12. The first core assembly 5 drives the core 1 and the water cooling joint to slide along the sliding hole. When the first core assembly 5 drives the core 1 to slide, the joint of the water cooling assembly 6 moves synchronously with the core 1, ensuring that the cooling process is not interrupted.

[0035] In this embodiment, the core 1 is a first steel core, and the core low-pressure mold further includes a second steel core 8. The second steel core 8 is in sliding fit with the lower mold 4, one end of the second steel core 8 faces the core 1 and penetrates into the forming cavity 11, and the water cooling channel 12 is arranged in the second steel core 8. The forming gap 10 is formed between the core 1 and the second steel core 8.

[0036] The second steel core 8 is in sliding fit with the lower mold 4 and penetrates into the forming cavity 11, and the water cooling channel 12 in the second steel core 8 can perform targeted cooling on the local area of the forming cavity 11, thereby optimizing the product forming effect. The second core assembly 9 drives it to move independently, so that the mold can adapt to more complex product structure forming requirements. At the same time, the water cooling design of the double steel cores further improves the temperature control capability of the mold as a whole, and reduces the influence of thermal deformation on sealing and dimensional accuracy.

[0037] In this embodiment, the first core-pulling assembly 5 and the second core-pulling assembly 9 can adopt the same structural form, and the core function is to drive the core-pulling 1 or the second steel core 8 to accurately stretch and retract in the axial direction. The common structural form can adopt a cylinder / hydraulic cylinder driving structure, the piston rod of the cylinder or hydraulic cylinder is rigidly connected with the driving end of the core-pulling 1 (or the second steel core 8), and the linear reciprocating motion is realized by using the gas pressure or hydraulic power. The advantage of this structure is that the driving force is stable and the stroke control is accurate. The movement speed and thrust can be controlled by adjusting the gas pressure / hydraulic pressure parameters to adapt to the needs of the core-pulling 1 action at different forming stages, and it is easy to integrate with the control system of the production line to realize automatic linkage.

[0038] The first core-pulling assembly 5 and the second core-pulling assembly 9 can also adopt a lead screw nut transmission structure, which drives the lead screw to rotate by a motor, and converts the linear motion of the core-pulling 1 through the nut. The characteristic of this structure is high positioning accuracy, which can accurately control the length of the core-pulling 1 inserted into the forming cavity 11 through the motor encoder. It is especially suitable for scenes with strict size accuracy requirements, and there is no rigid impact in the transmission process, which can reduce the wear of the core-pulling 1 and the guide sleeve 2.

[0039] Both structures can be installed horizontally or vertically according to the layout of the mold, and the linear degree of the core-pulling 1 motion is ensured through auxiliary components such as guide blocks to avoid sealing failure or structural wear caused by partial load.

[0040] The water cooling assembly 6 needs to realize the continuous cooling of the core-pulling 1 or the second steel core 8, and at the same time adapt to the stretching and retracting motion of the core-pulling 1. It can be a rotary joint type structure, which is composed of a rotary joint fixedly connected with the core-pulling 1 and an external cooling water pipeline. The rotary joint can move synchronously with the core-pulling 1, and the internal flow passage is connected with the external pipeline through a sealing element. The cooling liquid enters the water cooling channel 12 of the core-pulling 1 through the rotary joint, and is discharged from the water return flow passage after absorbing heat. The core of this form is a dynamic sealing structure, which can maintain the waterway unobstructed during the reciprocating motion of the core-pulling 1, avoiding leakage. A hose type assembly can also be used, which directly connects the water cooling channel 12 of the core-pulling 1 with the opening of the flexible cooling hose. The length of the hose is reserved with a redundancy of the maximum stroke of the core-pulling 1. When the core-pulling 1 stretches and retracts, the hose bends or straightens synchronously with it, and the cooling liquid circulates through the hose continuously. This form of structure is simple and has lower cost, which is suitable for scenes with shorter stroke and lower motion frequency of the core-pulling 1. Attention should be paid to the temperature resistance and fatigue resistance of the hose to avoid aging and rupture after long-term use.

[0041] The water cooling assembly 6 also includes a flow control valve and a temperature sensor, which can adjust the cooling liquid flow according to the actual working temperature of the core-pulling 1, to avoid energy waste while ensuring the cooling effect.

[0042] For example, Figure 1 and Figure 2As shown, wear-resistant block 3 is provided between core pulling assembly 1 and lower mold 4. Multiple wear-resistant blocks 3 of different thickness specifications can be replaced and installed to control the gap between core pulling assembly 1 and lower mold 4, thereby controlling the length of core pulling assembly 1 inserted into forming cavity 11, solving the problem of position deviation caused by wear of core pulling assembly 1 in long-term production. By simply replacing wear-resistant block 3, size deviation can be compensated for, ensuring the consistency of product wall thickness and avoiding waste caused by inaccurate position of core pulling assembly 1.

[0043] In this embodiment, wear-resistant block 3 of 40Cr material is added at the end of core pulling assembly 1, which is heat treated to a high hardness of HRC55. For the wear problem of core pulling assembly 1 in long-term use, 40Cr steel has excellent comprehensive mechanical properties. After heat treatment, the hardness is improved to HRC55, forming a surface property that can resist the frictional wear of the reciprocating motion of core pulling assembly 1, which is much higher than the hardness of HRC38-42 of the main body of core pulling assembly 1, effectively slowing down the wear rate of the limiting position and prolonging the stable working period of core pulling assembly 1 as a whole.

[0044] Through the design of detachable replacement, quick size compensation is achieved. During initial processing of the mold, there may be slight precision deviations. After long-term production, even high-hardness wear-resistant block 3 will also wear out, all of which will cause slight changes in the length of core pulling assembly 1 inserted into forming cavity 11, thereby affecting the product wall thickness size. The detachable nature of wear-resistant block 3 allows for direct replacement of wear-resistant blocks 3 of different thickness specifications according to actual conditions, without the need for complex processing of the mold body. By simply replacing the accessories, the limiting position of core pulling assembly 1 can be quickly adjusted to compensate for size deviations caused by wear or processing errors, ensuring that the length of core pulling assembly 1 inserted into forming cavity 11 always meets the design requirements, thereby stably controlling the product wall thickness and ensuring product quality. The complex mold maintenance is simplified to easy-to-operate accessory replacement, significantly reducing downtime caused by size adjustment and further improving production efficiency.

[0045] The integrally formed guide sleeve 2 strengthens the stability of the basic structure, the precise fit of the tapered shaft section and the conical surface improves the reliability of the seal, the water cooling system reduces the risk of thermal deformation and aluminum liquid adhesion from the root, and the adjustable wear-resistant block 3 solves the problem of size deviation in long-term use. The structures cooperate with each other, not only consolidating the core role of the conical seal 7, but also covering the derived problems such as wear and thermal deformation that may occur during production, forming a performance guarantee system throughout the cycle.

[0046] The sealing design of guide sleeve 2 improves the overall strength of the mold and reduces the risk of cracking; the water cooling system prolongs the service life of core pulling assembly 1 and reduces the maintenance frequency; the adjustable wear-resistant block 3 realizes quick online adjustment and reduces downtime; the addition of the second steel core 8 enhances the molding capacity of the mold for complex products. The mold not only maintains a stable production rhythm, but also further improves product quality and reduces overall production cost.

[0047] Embodiment 2 In another typical embodiment of the present application, as shown in Figures 1-2 a molding method of the core-pulling low-pressure mold is given, which utilizes the core-pulling low-pressure mold in embodiment 1, and specifically comprises: The upper mold is buckled with the lower mold 4 to form a cavity for molding, and the outer part of the guide sleeve 2 of the lower mold 4 is attached to the corresponding position of the upper mold to ensure overall sealing; The core-pulling 1 is inserted from the other end of the sliding hole of the outer wall of the lower mold 4, so that the feature end of the core-pulling 1 moves towards the molding cavity 11; when the feature end is inserted into the molding cavity 11, the outer peripheral wall of the core-pulling 1 is tightly attached to the tapered surface at the opening of the sliding hole, forming a tapered sealing 7, which completely isolates the sliding hole from the molding cavity 11; The raw material is injected into the molding cavity 11 to form the required workpiece by using the mold cavity, and the tapered sealing 7 prevents the raw material from entering the sliding hole, causing material sticking or material running; the core-pulling 1 is cooled through the water cooling channel 12 inside the core-pulling 1; After molding is completed, the core-pulling 1 is withdrawn from the molding cavity 11 by applying external force to the driving end, the feature end exits the molding cavity 11, and the tapered sealing 7 is released; the upper mold is separated from the lower mold 4, and the molded product is taken out; The above steps of mold closing, core-pulling 1 positioning, molding, mold opening and part taking are repeated to realize continuous production.

[0048] The core-pulling 1 is installed inside the sliding hole of the guide sleeve 2 of the lower mold, and the aluminum liquid cannot enter, effectively controlling the problem of sticking aluminum. Since the core-pulling 1 has a water cooling channel 12 inside, it can provide cooling function for the temperature rise of the core-pulling 1 caused by continuous production, ensuring the size, and the mold can be continuously produced for 10 shifts, improving the production efficiency. The wear-resistant block 3 at the end of the core-pulling 1 effectively solves the problem of over-difference caused by the active collision and wear of the core-pulling 1 of the original mold, because the wear-resistant block 3 can be replaced, the failed wear-resistant block 3 can be adjusted on the machine, and the hardness of the accessory is improved, improving the wear resistance.

[0049] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A core-drawing low pressure mold characterized by, The upper die and the lower die are buckled to form a molding cavity, the guide sleeve is provided on the lower die, a sliding hole is provided in the guide sleeve for the core pulling to pass through and form a sliding fit, the outer part of the guide sleeve is attached to the corresponding position of the upper die, one end of the sliding hole is open and communicates with the molding cavity, a tapered surface is formed at the one end opening position, and the other end opening extends to the outer wall of the lower die, one end of the core pulling is a characteristic end capable of exploring or withdrawing from the molding cavity, and the other end is a driving end subjected to external force, when the characteristic end explores into the molding cavity, the outer peripheral wall of the core pulling is attached to the tapered surface to form a tapered surface seal, so as to isolate the sliding hole and the molding cavity.

2. The undercut low pressure mold of claim 1, wherein, The guide sleeve is integrally formed with the main body part of the lower die or the guide sleeve is sealingly embedded in the lower die, and the diameter of the tapered surface gradually increases in the direction away from the molding cavity along the axis of the sliding hole.

3. The draw core low pressure mold of claim 2, wherein, The segment of the core pulling connected to the molding end is provided with a gradual change shaft segment capable of being attached and sealed with the tapered surface.

4. The undercut low pressure mold of claim 1, wherein, The core pulling is internally provided with a water cooling channel, and the opening of the water cooling channel is arranged at the segment of the core pulling outside the sliding hole and connected to a water cooling assembly.

5. The draw core low pressure mold of claim 4, wherein, The driving end of the core pulling is connected to a first core pulling assembly, the joint of the water cooling assembly is connected to the opening of the water cooling channel, and the first core pulling assembly drives the core pulling and the water cooling joint to slide along the sliding hole.

6. The draw core low pressure mold of claim 5, wherein, A wear-resistant block is arranged between the core pulling assembly and the lower die, and wear-resistant blocks of different thicknesses can be replaced and installed to control the gap between the core pulling assembly and the lower die, so as to control the length of the core pulling exploring into the molding cavity.

7. The draw core low pressure mold of claim 1, wherein, A second steel core is further included, the second steel core is in sliding fit with the lower die, one end of the second steel core faces the core pulling and explores into the molding cavity, and a water cooling channel is arranged in the second steel core.

8. The draw core low pressure mold of claim 7, wherein, The end of the second steel core away from the molding cavity extends to the outside of the lower die and is connected to a second core pulling assembly to drive the second steel core to explore or withdraw from the molding cavity.

9. A molding method of a core-drawing low-pressure mold using the core-drawing low-pressure mold according to any one of claims 1 to 8, characterized by, The upper die and the lower die are buckled to form a molding cavity, the guide sleeve is provided on the lower die, a sliding hole is provided in the guide sleeve for the core pulling to pass through and form a sliding fit, the outer part of the guide sleeve is attached to the corresponding position of the upper die, one end of the sliding hole is open and communicates with the molding cavity, a tapered surface is formed at the one end opening position, and the other end opening extends to the outer wall of the lower die, one end of the core pulling is a characteristic end capable of exploring or withdrawing from the molding cavity, and the other end is a driving end subjected to external force, when the characteristic end explores into the molding cavity, the outer peripheral wall of the core pulling is attached to the tapered surface to form a tapered surface seal, so as to isolate the sliding hole and the molding cavity. The guide sleeve is integrally formed with the main body part of the lower die or the guide sleeve is sealingly embedded in the lower die, and the diameter of the tapered surface gradually increases in the direction away from the molding cavity along the axis of the sliding hole. The segment of the core pulling connected to the molding end is provided with a gradual change shaft segment capable of being attached and sealed with the tapered surface. The core pulling is internally provided with a water cooling channel, and the opening of the water cooling channel is arranged at the segment of the core pulling outside the sliding hole and connected to a water cooling assembly. The driving end of the core pulling is connected to a first core pulling assembly, the joint of the water cooling assembly is connected to the opening of the water cooling channel, and the first core pulling assembly drives the core pulling and the water cooling joint to slide along the sliding hole. A wear-resistant block is arranged between the core pulling assembly and the lower die, and wear-resistant blocks of different thicknesses can be replaced and installed to control the gap between the core pulling assembly and the lower die, so as to control the length of the core pulling exploring into the molding cavity.

10. The molding method of a draw core low pressure mold according to claim 9, wherein, A second steel core is further included, the second steel core is in sliding fit with the lower die, one end of the second steel core faces the core pulling and explores into the molding cavity, and a water cooling channel is arranged in the second steel core. The end of the second steel core away from the molding cavity extends to the outside of the lower die and is connected to a second core pulling assembly to drive the second steel core to explore or withdraw from the molding cavity. The upper die and the lower die are buckled to form a molding cavity, the guide sleeve is provided on the lower die, a sliding hole is provided in the guide sleeve for the core pulling to pass through and form a sliding fit, the outer part of the guide sleeve is attached to the corresponding position of the upper die, one end of the sliding hole is open and communicates with the molding cavity, a tapered surface is formed at the one end opening position, and the other end opening extends to the outer wall of the lower die, one end of the core pulling is a characteristic end capable of exploring or withdrawing from the molding cavity, and the other end is a driving end subjected to external force, when the characteristic end explores into the molding cavity, the outer peripheral wall of the core pulling is attached to the tapered surface to form a tapered surface seal, so as to isolate the sliding hole and the molding cavity. The guide sleeve is integrally formed with the main body part of the lower die or the guide sleeve is sealingly embedded in the lower die, and the diameter of the tapered surface gradually increases in the direction away from the molding cavity along the axis of the sliding hole. The segment of the core pulling connected to the molding end is provided with a gradual change shaft segment capable of being attached and sealed with the tapered surface. The core pulling is internally provided with a water cooling channel, and the opening of the water cooling channel is arranged at the segment of the core pulling outside the sliding hole and connected to a water cooling assembly. The driving end of the core pulling is connected to a first core pulling assembly, the joint of the water cooling assembly is connected to the opening of the water cooling channel, and the first core pulling assembly drives the core pulling and the water cooling joint to slide along the sliding hole. A wear-resistant block is arranged between the core pulling assembly and the lower die, and wear-resistant blocks of different thicknesses can be replaced and installed to control the gap between the core pulling assembly and the lower die, so as to control the length of the core pulling exploring into the molding cavity. A second steel core is further included, the second steel core is in sliding fit with the lower die, one end of the second steel core faces the core pulling and explores into the molding cavity, and a water cooling channel is arranged in the second steel core. The end of the second steel core away from the molding cavity extends to the outside of the lower die and is connected to a second core pulling assembly to drive the second steel core to explore or withdraw from the molding cavity.

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