Split mold

Abstract

The application provides a combined mold for casting a model, comprising an outer mold and an inner mold, the outer mold at least partially containing the inner mold, a mold space being formed between the outer mold and the inner mold for forming the model, the outer mold comprising an injection hole communicating with the mold space, characterized in that the inner mold comprises a middle core mold and a combined core mold, the combined core mold having a combined core mold hole forming a shaft hole fit with the middle core mold, the inner mold further comprising a water outlet core mold and a water inlet core mold arranged in fit with the combined core mold, the middle core mold, the water outlet core mold and the water inlet core mold all being metal materials, and the combined core mold being a flexible rubber material capable of being deformed. In the application, the combined core mold is made of silica gel material and is easier to be taken out from the model cavity, and an integrated casting model is realized.

Description

Technical Field

[0001] This invention relates to the field of molds, and in particular to a combined mold for producing an integral cast water meter. Background Technology

[0002] In the precision casting process, a wax model designed to be 1:1 with the product to be cast must first be cast. Then, a mold cavity is made from the wax model, and molten metal is poured into the mold cavity. After cooling, the mold layer is removed to obtain the prototype of the product. For products with fine internal structures, existing technologies usually have two processing methods: (1) In order to facilitate demolding during the wax model casting process, a split casting process is usually used for wax model casting. That is, the wax model is divided into multiple parts for casting and then assembled. In this way, demolding of the wax model is simpler during casting and the design of the casting mold is simpler. After the split wax model is formed by casting, the wax model is then connected and assembled. This connection method can be adhesive or mechanical. After the wax model is assembled into a whole, the subsequent metal casting process is carried out. This method may cause misalignment and gaps at the joint of the assembled wax model due to positioning issues in the combination method. For models with high closure requirements, such as water meters, these problems will lead to casting defects when casting water meters. Especially when using stainless steel for casting, because the fluidity of stainless steel itself is not easy to flow and form compared to other easily cast materials such as copper, it will further affect the casting yield and the cost input in the manufacturing process. (2) Casting a split wax model, and then casting the metal of each part of the product according to the split wax model. After forming each part of the product, the parts of the product are then combined by welding. Using this method to produce products, the welded products are prone to poor joint at the welding position, resulting in a decrease in the overall rigidity and safety of the product. If the above two methods are not adopted, the wax model with the inner cavity needs to be cast as a whole. The inner cavity needs to be arranged with a fine and easy-to-pull mold. The combination and removal of the mold are difficult problems to solve. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention proposes a combined mold that can integrally cast the model in the water meter casting process, thereby overcoming the aforementioned shortcomings of the prior art.

[0004] The technical solution adopted by this invention to solve the problems of the prior art is:

[0005] A composite mold for casting a model includes an outer mold and an inner mold. The outer mold at least partially encloses the inner mold, and a casting space is provided between the outer mold and the inner mold for forming the model. The outer mold includes an injection hole communicating with the casting space. The inner mold is characterized in that it includes a central core mold and a composite core mold. The composite core mold has a composite core mold hole that mates with the central core mold. The inner mold also includes an outlet core mold and an inlet core mold that mate with the composite core mold. The central core mold, the outlet core mold, and the inlet core mold are all made of metal, and the composite core mold is made of a deformable flexible rubber material.

[0006] Unlike existing technologies, the core mold in this invention leaves a large space in the model after it is removed from the model, allowing the combined core mold to move and deform within the model's cavity. The combined core mold is made of a flexible rubber material that can deform easily, thus facilitating its removal from the cavity and enabling integrated casting.

[0007] In one embodiment, the flexible rubber material is specifically silicone.

[0008] In one embodiment, the combined core mold is adapted to different sized cavities by selecting and setting an upper core mold and a lower core mold.

[0009] In one embodiment, the upper core mold is made of a material with a different hardness than the lower core mold.

[0010] In one embodiment, the outer mold has a first part and a second part, and the inner mold is disposed between the first part and the second part. The first part forms a first casting cavity, and the second part forms a second casting cavity. The first casting cavity and the second casting cavity constitute the casting cavity, which adapts to the outer surface contour of the model, and the inner mold adapts to the inner surface contour of the model.

[0011] In one embodiment, the combined core mold has a separate upper core mold and a lower core mold, the upper core mold and the lower core mold respectively have an upper core mold hole and a lower core mold hole, and the middle core mold passes through the upper core mold hole and is inserted into the lower core mold hole.

[0012] In one embodiment, the middle core mold has an upper step portion and a lower step portion corresponding to the upper core mold and the lower core mold.

[0013] In one embodiment, the inner mold includes a check mold, the upper mold has a check pin, and the check mold and the upper mold are perpendicularly fitted through a shaft hole.

[0014] In one embodiment, the check pin extends toward the lower core mold, and the check pin is quadrangular.

[0015] In one embodiment, the inner mold further includes a functional mold disposed between the check pin and the lower core mold. The functional mold is connected in conjunction with the check core mold, and the material hardness of the functional mold is less than that of the upper core mold and the lower core mold.

[0016] In one embodiment, the outlet mandrel includes a straight section and a connecting section, the straight section extending perpendicular to the central axis of the combined mandrel hole, and the connecting section having a protruding portion that fits into the check mandrel.

[0017] In one embodiment, the lower core mold has a water inlet pin that mates with the water inlet core mold, and the size of the water inlet pin gradually decreases in the direction of the water inlet core mold. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the combined mold in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the combined mold from another perspective in an embodiment of the present invention.

[0021] Figure 3 This is a top view of the combined mold in an embodiment of the present invention.

[0022] Figure 4 for Figure 3 Cross-sectional view along the AA direction.

[0023] Figure 5 This is a partial disassembly diagram of the combined mold in an embodiment of the present invention.

[0024] Figure 6 This is a fully disassembled diagram of the combined mold in an embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram of the water meter.

[0026] Figure 8 This is a cross-sectional view of the water meter. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] like Figure 1 , 2 As shown in Figures 3 and 4, the combined mold 10 is used for casting the model. The combined mold 10 includes an outer mold 11 and an inner mold 12, with the inner mold 12 assembled and positioned within the outer mold 11. There is a gap between the outer mold 11 and the inner mold 12, forming a casting space 13. The outer mold 11 and the inner mold 12 have contacting portions, which restrict the movement of the inner mold 12, achieving its positioning relative to the outer mold 11, and also forming the edge of the casting space 13. The outer mold 11 has an injection hole 110 communicating with the casting space 13. The model in its solution state is injected into the combined mold 10 through the injection hole 110 and then enters the casting space 13. The shape of the casting space 13 determines the shape of the model. In this embodiment, the model is a water meter wax model.

[0031] The outer mold 11 has a first part 111 and a second part 112, both of which have inner cavities. The inner cavities are symmetrically arranged relative to the assembly surface of the two parts. The inner cavities are designed to conform to the outer surface contour of the cast water meter. The first part 111 forms a first casting inner cavity, and the second part 112 forms a second casting inner cavity. The first and second casting inner cavities constitute the casting inner cavity, conforming to the outer surface contour of the model. The inner mold 12 conforms to the inner surface contour of the model.

[0032] An inner mold 12 is disposed between the first part 111 and the second part 112, and the inner mold 12 adapts to the inner surface of the water meter being cast. The three parts together form a casting space 13, the positions of which adapt to the wall thickness of the water meter casing. A limiting mechanism 113 is provided between the first part 111 and the second part 112 to restrict the relative movement of the first part 111 and the second part 112 during casting. The limiting mechanism 113 includes a groove and a boss, a pin and a hole.

[0033] like Figure 7 , 8 As shown, the water meter 20 includes a main body 21 and an inlet pipe 22 and an outlet pipe 23 connected to the main body 21. The main body 21 has a receiving cavity 210 and an opening 211. The receiving cavity 210 is used to place the water meter core, and the opening 211 is sealed with transparent glass for easy observation of the water meter core. The inlet pipe 22 has an inlet 220, and the outlet pipe 23 has an outlet 230. The receiving cavity 20 is connected to the inlet channel 221 through a receiving cavity inlet 271, and the receiving cavity 20 is connected to the outlet channel 231 through a receiving cavity outlet 261. The lumens of the inlet pipe 22 and the outlet pipe 23 are connected to the receiving cavity 210. Water enters the receiving cavity 210 from the inlet channel 22, flows through the water meter core, and then flows out from the outlet channel 23. The receiving cavity 210 includes an upper ring chamber 26 that communicates with the water inlet channel 221 and a lower ring chamber 27 that communicates with the water outlet channel, and a step portion 28 for separation is provided between the upper ring chamber 26 and the lower ring chamber 27.

[0034] like Figure 4 , 6 As shown, the inner mold 12 includes a central core mold 121, a combined core mold 122, a water outlet core mold 125, and a water inlet core mold 126. The combined core mold 122 has a combined core mold hole 1220, which forms a shaft hole connection with the central core mold 121. The combined core mold hole 1220 is a blind hole. During the casting process, the water outlet core mold 125 and the outer mold 11 form the water outlet pipe; the water inlet core mold 126 and the outer mold 11 form the water inlet pipe; the central core mold 121 is inserted into the combined core mold hole 1220 and forms the main body with the outer mold 11.

[0035] The central core mold 121, the outlet core mold 125, and the inlet core mold 126 are all made of metal. For ease of demolding, the combined core mold 122 is made of a flexible, deformable rubber material; specifically, in this embodiment, silicone is used. Compared to metal, flexible rubber materials like silicone are softer and can be easily removed during demolding through significant deformation, resulting in high demolding efficiency and reduced design requirements. Furthermore, silicone has better heat resistance than metal and is less conductive. Metal molds require a cooling period after multiple uses, while silicone molds can be used continuously for extended periods. Additionally, silicone molds exhibit less thermal deformation and higher positioning accuracy, resulting in a more precise wax model. This significantly improves subsequent casting yield and ensures a more precise water meter casing, enhancing counting stability and safety. The hardness of the silicone material can be adjusted based on the varying thicknesses of the complex structures within the formed cavity, thereby reducing mold costs.

[0036] When removing the mold after casting is complete, first open the outer mold 11, then remove the middle core mold 121, the water outlet core mold 125, and the water inlet core mold 126, and then remove the combined core mold 122 from the receiving cavity 210 of the water meter wax mold. Moreover, the combined core mold is made of silicone. Although the space of the receiving cavity 210 is small, after the middle core mold 121 is removed, space is left for the combined core mold hole 1220. Furthermore, the combined core mold 122 is made of silicone, which can deform using the space of the combined core mold hole 1220, thus allowing it to be easily removed from the opening 211 of the main body 21.

[0037] The water meter wax mold receiving cavity 210 is cast using a silicone composite core mold 122, and the other parts of the water meter wax mold are cast using a metal mold, thus realizing the one-piece casting of the water meter wax mold and improving the quality, accuracy, rigidity and safety of the water meter wax mold and the finished water meter.

[0038] Correspondingly, the combined core mold 122 also has an upper core mold 1221 and a lower core mold 1222 to accommodate the separately arranged upper annular chamber 26 and lower annular chamber 27 of different sizes. The upper core mold 1221 and the lower core mold 1222 are separately arranged and are used to cast the upper annular chamber 26 and the lower annular chamber 27, respectively. The upper core mold 1221 and the lower core mold 1222 have an upper core mold hole 12210 and a lower core mold hole 12220, respectively. The upper core mold hole 12210 is a through hole, and the lower core mold hole 12220 is a blind hole. The middle core mold 121 passes through the upper core mold hole 12210 and is inserted into the lower core mold hole 12220.

[0039] An upper step portion 1211 and a lower step portion 1212 are formed on the central core mold 121, corresponding to the upper core mold 1221 and the lower core mold 1222, respectively. During casting, the upper step portion 1211 abuts against the upper core mold 1221, and the lower step portion 1212 abuts against the lower core mold 1222. This ensures that the above-mentioned parts are assembled in place and facilitates the demolding of the central core mold 121 relative to the upper core mold 1221 and the lower core mold 1222.

[0040] The upper core mold 1221 and the lower core mold 1222 are made of different materials, and their hardness is also different. In this embodiment, the hardness of the upper core mold 1221 is greater than that of the lower core mold 1222. This is because the radial dimension of the step portion 28 between the upper ring chamber 26 and the lower ring chamber 27 is smaller than that of the upper ring chamber 26 and the lower ring chamber 27, while the size of the water inlet pin 12221 of the lower core mold 1222 is larger. Therefore, when the lower core mold 1222 is removed, it needs to undergo greater deformation.

[0041] like Figure 7 , 8As shown, a check channel 25 is provided on the water outlet pipe 23 of the water meter 20, including a check wall 232. A check cavity 250 connected to the water outlet channel 23 is formed in the check wall 232. The check cavity 250 is at an angle to the water outlet channel 23. The check wall 232 surrounds the check cavity 250 and has a check hole 252 and a check opening 251 opposite to the check hole 252. The check wall 232 includes an inclined wall 2321 provided in the water outlet pipe and a connecting wall 2322 vertically connected to the inclined wall 2321. The check hole 252 is opened in the inclined wall and connects a check channel 24 and the water outlet channel 23. A check valve is provided in the check cavity 250 to prevent water from flowing backward. The check opening 251 is used to insert the check valve.

[0042] Correspondingly, the inner mold 12 includes a check mandrel 124, and the upper mandrel 1221 has a check pin 12211. The check mandrel 124 and the upper mandrel 1221 are assembled and positioned to form a check cavity 250, a check hole 252, and a check flow channel 24 communicating with the check cavity 250. The check mandrel 124 is also made of metal, which helps in the positioning of the check pin 12211 of the upper mandrel 1221. The check mandrel 124 is at an angle to the central axis of the upper mandrel hole 12210 to form an angled check cavity 250 structure. The check mandrel 124 and the check pin 12211 are positioned through a shaft hole. The upper surface of the check pin 12211 is perpendicular to the axial direction of the check mandrel 124, forming a check cavity 250 between them to cast the check wall 232 of the water meter mold. Since the upper ring chamber 26 is higher than the lower ring chamber 226, the check cavity 250 connects the upper ring chamber 26 and the outlet 230. In order to maintain the height difference range between the outlet 230 and the inlet 220, the direction of the check pin 12211 is designed to be biased towards the direction of the lower core mold 1222. The check pin 1221 is set as a quadrangular prism, and the cross section of the end near the upper ring chamber 26 is larger than the cross section of the end near the check hole. The middle part is smoothly transitioned. The quadrangular prism design ensures that after the water in the water meter cavity flows out of the outlet of the upper ring chamber 26, it accelerates into the check channel and has a relatively large water pressure to open the check component in the check cavity, so as to open the check hole 252. The check chamber 250 is designed to be inclined towards the outlet side. The check wall 232 where the check hole 252 is located is set perpendicular to the axis of the check chamber 250. The water flowing out of the check chamber 250 presses against the check hole 252 and has an accelerating water pressure towards the outlet, ensuring that the water flows out at high speed.

[0043] like Figure 4 , 5As shown, because the check pin 12211 extends towards the lower core mold 1222, the thickness of the mold space 13 between the check pin 12211 and the lower core mold 1222 is significantly greater than the thickness of other mold spaces 13. This results in a wall thickness in this region being greater than in other regions, leading to problems such as internal stress and stress concentration in this area. To avoid this problem, a functional mold 127 is provided between the check pin 12211 and the lower core mold 1222 to reduce the thickness of the mold space 13 in this region, allowing the groove region 29 of the water meter model formed by the functional mold 127 to be connected to the check flow channel 24. Because the functional mold 127 is an independent core mold, it is connected to the check core mold 124 to position it, preventing displacement of the functional mold 127 within the outer mold 11 during casting. Furthermore, because the functional mold 127 is located on the bottom side of the check pin 12211, it is inconvenient to design it as an integral structure with the check pin 12211, in order to prevent the functional mold 127 from being unable to be pulled out from the upper ring chamber outlet. Also, the cross-sectional area of ​​the functional mold 127 in the axial direction perpendicular to the check core mold is larger than the area of ​​the check port, thus making it inconvenient to design it as an integral structure with the check core mold. Therefore, in this embodiment, the functional mold 127 is an independent core mold structure. The material hardness of the functional mold 127 is similar to that of the upper core mold 1221, and greater than that of the lower core mold 1222. This is because the functional mold 127 is smaller in size, making it easier to remove. Moreover, silicone materials with higher hardness are cheaper than silicone materials with lower hardness; therefore, using silicone materials with higher hardness is also a cost consideration.

[0044] The water outlet core mold 125 and the check mold core 124 are assembled and fitted to form a water outlet channel and a water outlet. The water outlet core mold 125 and the check mold core 124 are attached to one side surface to make the water outlet channel communicate with the check cavity. The water outlet core mold 125 includes a straight section 1251 and a connecting section 1252. The extension direction of the straight section 1251 is perpendicular to the central axis of the combined core mold hole 1220. The connecting section 1252 has a protruding portion that fits against the check mold core 124. During demolding, the straight section 1251 is removed first, and then the connecting section 1252 is removed.

[0045] The inlet core mold 126 and the inlet pin 12221 of the lower core mold 1222 cooperate to form an inlet channel. The size of the inlet pin 12221 gradually decreases towards the inlet core mold 126, which makes the size of the inlet channel gradually increase along the water inlet direction. This is beneficial for water to enter the water meter housing more quickly and flow smoothly into the lower ring chamber, and also facilitates the removal of the lower core mold 1222. There is a height difference between the inlet pin 12221 and the lower core mold 1222, which allows water to flow more smoothly from the inlet to the lower ring chamber.

[0046] In casting the water meter wax model, the wax model material in solution state, specifically paraffin wax in this embodiment, is injected into the combined model through the injection hole 110 and enters the casting space 13. After the model cools and solidifies, it detaches from the cavity of the outer mold 11, and the inner mold 12 needs to be extracted from the model so that the independent mold can be transferred to subsequent process steps. To avoid the rigid inner mold 12 from colliding and damaging the model when it is extracted, the middle core mold 121, check valve core mold 124, water outlet core mold 125, and water inlet core mold 126 are first removed. Then, the space between the upper core mold hole 12210 and the lower core mold hole 12220 is used to deform the upper core mold 1221 and the lower core mold 1222, preventing the check valve pin 12211 and the water inlet pin 12221 from colliding with the model, thereby removing the upper core mold 1221 and the lower core mold 1222 from the opening of the water meter wax model. Finally, the functional mold 127 is removed from the check channel 24 or the check hole 252. Specifically, the flexible core molds (upper core mold 1221, lower core mold 1222, and functional mold 127) can be removed by using tweezers or other slender tools to pick them up or grasp them. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A combined mold (10) for casting a model, comprising an outer mold (11) and an inner mold (12), the outer mold (11) at least partially encompassing the inner mold (12), a casting space (13) being provided between the outer mold (11) and the inner mold (12) for forming the model, the outer mold (11) including an injection hole (110) communicating with the casting space (13), characterized in that, The inner mold (12) includes a central core mold (121) and a combined core mold (122). The combined core mold (122) has a combined core mold hole (1220) that mates with the central core mold (121) to form a shaft hole. The inner mold (12) also includes an outlet core mold (125) and an inlet core mold (126) that mate with the combined core mold (122). The central core mold (121), the outlet core mold (125), and the inlet core mold (126) are all made of metal. The combined core mold (122) is made of a deformable flexible rubber material. The inner mold (12) includes a check valve core mold (124). The combined core mold (122) The inner mold (12) is configured with an upper core mold (1221) and a lower core mold (1222) to accommodate cavities of different sizes. The upper core mold (1221) has a check pin (12211). The check pin (124) is vertically fitted to the upper core mold (1221) via a shaft hole. The inner mold (12) also includes a functional mold (127) disposed between the check pin (12211) and the lower core mold (1222). The functional mold (127) is connected to the check pin (124). The material hardness of the functional mold (127) is less than that of the upper core mold (1221) and the lower core mold (1222).

2. The combined mold (10) according to claim 1, characterized in that The flexible rubber material is specifically silicone.

3. The combined mold (10) according to claim 1, characterized in that, The material of the upper core mold (1221) is different from the material hardness of the lower core mold (1222).

4. The combined mold (10) according to claim 1, characterized in that The outer mold (11) has a first part (111) and a second part (112), and the inner mold (12) is disposed between the first part (111) and the second part (112). The first part (111) forms a first casting cavity, and the second part (112) forms a second casting cavity. The first casting cavity and the second casting cavity constitute the casting cavity, which adapts to the outer surface contour of the model, and the inner mold adapts to the inner surface contour of the model.

5. The combined mold (10) according to claim 1, characterized in that, The upper core mold (1221) and the lower core mold (1222) are separately set. The upper core mold (1221) and the lower core mold (1222) have an upper core mold hole (12210) and a lower core mold hole (12220) respectively. The middle core mold (121) passes through the upper core mold hole (12210) and is inserted into the lower core mold hole (12220).

6. The combined mold (10) according to claim 5, characterized in that The middle core mold (121) has an upper step portion 1211 and a lower step portion (1212) corresponding to the upper core mold (1221) and the lower core mold (1222).

7. The combined mold (10) according to claim 5, characterized in that The check pin (12211) extends toward the lower core mold (1222), and the check pin (12211) is quadrangular.

8. The combined mold (10) according to claim 1, characterized in that The water outlet core mold (125) includes a straight section (1251) and a connecting section (1252). The extension direction of the straight section (1251) is perpendicular to the central axis of the combined core mold hole (1220). The connecting section (1252) has a protruding portion (12521) that fits into the check mold (124).

9. The combined mold (10) according to claim 3, characterized in that, The lower core (1222) has a water inlet pin (12221) matched with the water inlet core (126), and the size of the water inlet pin (12221) gradually decreases in the direction of the water inlet core (126).

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