Automobile planet carrier casting mold

Abstract

The invention relates to the technical field of casting molds, and discloses an automobile planet carrier casting mold which comprises a mold plate arranged between an upper mold and a lower mold, an upper sand mold, a lower sand mold, a sand core and a sprue are installed on the mold plate, and the sand core is located between the upper sand mold and the lower sand mold and used for blocking cavity communication of the upper sand mold and the lower sand mold; guide columns corresponding to the upper and lower dies are mounted on the upper and lower end faces of the template, and are inserted into guide holes of the upper and lower dies, so that accurate die assembly is realized. Through combination of the upper sand mold, the lower sand mold and the sand core, the mold can mold an upper casting and a lower casting at the same time by using the sand core to block communication of the mold cavity, the production efficiency is greatly improved, the thickness of the sand core is set to be 0.8 times of the wall thickness of the casting, shrinkage porosity linearity caused by a hot spot in the casting can be avoided, and meanwhile, the production efficiency is improved. The pouring gate supplies liquid to the upper sand mold and the lower sand mold through the residue filter, impurities in molten metal are removed through the filtering assembly, the shrinkage porosity defect caused by the impurities is reduced, and therefore the qualification rate of castings is increased.

Description

Technical Field

[0001] This invention relates to the field of casting mold technology, specifically to a casting mold for an automotive planetary carrier. Background Technology

[0002] The planetary carrier of an automobile is one of the core components of a planetary gear transmission. It is mainly used to support the planetary gears and connect other transmission components to achieve power transmission and speed regulation.

[0003] Currently, automotive planetary carriers are mostly manufactured using casting processes. However, in the context of large-scale casting of automotive planetary carriers, traditional molds, due to their simple design and weak defect control capabilities, are unable to meet the demands for efficient and high-quality production. Specific problems are as follows: 1. Traditional molds adopt a "one piece, one mold" design, which can only produce the upper or lower casting in a single pouring, resulting in low single-mold production efficiency and severely limited production capacity; 2. The traditional mold sand core thickness is not properly matched with the casting wall thickness, resulting in frequent shrinkage and porosity in the casting due to hot spots, and a low pass rate. This leads to a high rate of shrinkage and porosity defects in hot spot areas such as the five bosses of the planetary carrier. 3. Traditional molds lack efficient filtration components, allowing impurities such as oxides and sand particles (particle size ≥ 50 μm) in the molten metal to directly enter the mold cavity, resulting in non-metallic inclusions in the casting reaching level 3 (GB / T10561 standard), far exceeding the allowable level 1 upper limit, leading to a high shrinkage porosity defect rate in the casting.

[0004] In summary, as the automotive industry increases its requirements for the strength of transmission components, such as the tensile strength of planetary carriers needing to be ≥600MPa, the shortcomings of traditional molds in terms of efficiency and quality control have become the main obstacles to increasing production capacity. There is an urgent need to propose a new automotive planetary carrier casting mold to break through the bottleneck. Summary of the Invention

[0005] To address the technical problems existing in the background art, the present invention proposes an automotive planetary carrier casting mold.

[0006] The present invention proposes an automotive planetary carrier casting mold, including a mold plate disposed between an upper mold and a lower mold, wherein an upper sand mold, a lower sand mold, a sand core and a gate are installed on the mold plate, and the sand core is located between the upper sand mold and the lower sand mold to block the cavity communication between the upper sand mold and the lower sand mold; The thickness of the sand core is 0.8 times the thickness of the casting wall. This can prevent the formation of shrinkage porosity inside the casting. When the thickness of the sand core is greater than 0.8 times, shrinkage porosity will form inside the casting. When the thickness of the sand core is less than 0.8 times, it will form concave shrinkage on the surface of the casting. This solves the shrinkage porosity defect caused by hot spots and improves the production quality of castings.

[0007] The upper and lower end faces of the mold plate are provided with guide columns corresponding to the upper and lower molds, the guide columns are inserted into the guide holes of the upper and lower molds, so that precise mold closing is realized; the mold plate is provided with a slag filter, the sprue communicates with the cavities of the upper sand mold and the lower sand mold through the slag filter, and the slag filter is internally provided with a filtering assembly for removing impurities of the casting metal liquid; A primary filtering assembly is further arranged between the sprue and the slag filter, the primary filtering assembly is a metal liquid filtering piece commonly used in the prior art, can perform primary filtering on the metal liquid, and then perform secondary filtering through the slag filter, so that the purity of the metal liquid is improved and the impurity content is reduced. In view of the problems that the traditional mold can only produce single type and the castings are prone to shrinkage, the upper and lower castings are simultaneously formed through the combination of the upper sand mold, the lower sand mold and the sand core, the production efficiency is improved by 100%, the matching precision of the guide column and the guide hole reaches H7 / g6, the mold closing deviation is less than or equal to 0.1 mm, the cavity size is accurately ensured, the filtering assembly of the slag filter can intercept impurities greater than or equal to 50 mu m, the filtering efficiency is greater than or equal to 95%, and the castings caused by inclusions are reduced.

[0008] As a further optimized scheme of the present application, the slag filter comprises a base installed on the upper end of the mold plate and a cover body detachably installed on the upper end of the base, the cover body is clamped with the base and locked by fasteners, the base has two independent sprues in the inside, one end of the sprue has branch openings outside the base, and the two branch openings respectively communicate with the cavities of the upper sand mold and the lower sand mold, the other end of the sprue extends to the upper end of the base and is connected with the liquid outlet of the sprue through the filtering assembly; The double sprues of the base independently supply liquid to the upper and lower sand molds, avoiding mutual interference of the metal liquid, the clamping structure of the cover body and the base facilitates quick disassembly and maintenance, the fasteners are locked by M10 bolts with a torque of 15-20 N·m, the butt joint precision of the branch opening (10) and the sand mold cavity is ±0.5 mm, and the metal liquid is ensured to be filled smoothly.

[0009] As a further optimized scheme of the present application, the filtering assembly comprises a slag bucket detachably installed on the upper end of the base and a liquid inlet pipe installed on the upper end of the cover body, the upper end of the slag bucket is connected with the liquid inlet pipe through a butt joint pipe and sealed by a sealing element, the lower end of the slag bucket communicates with the adjacent sprue, and the end of the liquid inlet pipe away from the slag bucket communicates with the liquid outlet of the sprue through a liquid supply pipe; one end of the liquid supply pipe communicates with the liquid outlet of the sprue, the other end of the liquid supply pipe has two branch pipes and is Y-shaped, and the two branch pipes respectively communicate with the upper ends of the two liquid inlet pipes; The Y-shaped liquid supply pipe uniformly distributes the metal liquid to the two liquid inlet pipes, the flow deviation is less than or equal to 5%, the upper and lower sand molds are prevented from being unevenly filled, the butt joint of the slag bucket and the liquid inlet pipe is prevented from leaking the metal liquid by the sealing element, and the detachable design can shorten the replacement time of the slag bucket, facilitating actual maintenance and maintenance work.

[0010] As a further optimized scheme of the present application, the filter residue bucket comprises a tapered cylinder with an upper end diameter larger than a lower end diameter, the upper end of the tapered cylinder is fixedly communicated with the lower end of the butt joint pipe, the lower end of the tapered cylinder is detachably connected with the upper end of the base and is communicated with the adjacent runner, a foamed ceramic filter is installed inside the lower end of the tapered cylinder, and the foamed ceramic filter is sealed with the inner wall of the tapered cylinder by a refractory seal ring; The tapered cylinder guides the centripetal flow of the molten metal, improves the filtering efficiency, the porosity of the foamed ceramic filter (122) is 80%, the pore size is 50μm, and the filter can intercept impurities such as oxides and sand particles, the filtering efficiency is ≥98%, the refractory seal ring prevents the unfiltered molten metal from leaking from the gap, and ensures the reliable filtering effect.

[0011] As a further optimized scheme of the present application, the upper end of the base is provided with a fixing seat, a threaded hole is formed in the fixing seat, the end of the runner away from the branch opening extends upward and is communicated with the lower end of the threaded hole, the diameter of the threaded hole is larger than the diameter of the runner, the lower end of the tapered cylinder is provided with a threaded cylinder corresponding to and matched with the threaded hole, the lower end of the threaded cylinder is threadedly connected with the threaded hole and is sealed, the upper end surface of the fixing seat is provided with a fixing ring located outside the threaded hole and arranged in the center, and the upper end of the threaded cylinder is slidably connected with the inner wall of the fixing ring. The threaded cylinder is threadedly connected with the fixing seat, the fast positioning and sealing of the filter residue bucket are realized, the guidance of the fixing ring ensures that the tapered cylinder is coaxial with the runner, the sealing performance of the threaded connection avoids the overflow of the molten metal, and the production safety is ensured.

[0012] As a further optimized scheme of the present application, the sealing member comprises a counterweight ring and a first sealing ring, the first sealing ring is a hot isostatic pressing zirconia ceramic ring, the butt joint pipe is a nickel-based high-temperature alloy pipe, the counterweight ring is fixedly sleeved on the outer periphery of the lower end of the liquid inlet pipe and is pressed on the butt joint pipe, and the first sealing ring is sleeved on the liquid inlet pipe and is located between the counterweight ring and the butt joint pipe. The first sealing ring made of zirconia ceramic material is resistant to molten metal erosion, the butt joint pipe made of nickel-based high-temperature alloy material has a temperature resistance ≥1200℃, and the counterweight ring provides a continuous pressure to ensure that the sealing ring is tightly attached to the abutting surface and prevents high-temperature molten metal from leaking.

[0013] Further, the sealing member further comprises a second sealing ring, the second sealing ring is a flexible graphite ring formed by impregnating phosphate in high-purity expanded graphite, an annular sealing groove is formed in the upper end surface of the butt joint pipe and arranged in the center, and the second sealing ring is arranged in the annular sealing groove, a groove corresponding to and matched with the second sealing ring is formed in the lower end surface of the first sealing ring, and the gap between the contact surface of the first sealing ring and the butt joint pipe is sealed by the second sealing ring. The second sealing ring made of flexible graphite material can fill the microscopic gap between the first sealing ring and the butt joint pipe, further improving the sealing performance, and the phosphate impregnation treatment makes the graphite ring resistant to oxidation at a temperature of up to 800℃, adapting to the high-temperature environment of casting.

[0014] As a further optimized scheme of the present application, the sealing member further comprises a third sealing ring, which is arranged between the counterweight ring and the first sealing ring, and is a shape memory alloy ring made of NiTiNb; when the first sealing ring fails, the NiTiNb ring is activated at high temperature to expand and form a secondary mechanical seal (contact pressure > 40 MPa) with a triggering temperature of 650 DEG C (expansion amount after phase change 0.8%); The third sealing ring (24) made of NiTiNb shape memory alloy of the present application undergoes phase change at 650 DEG C, expands by 0.8%, forms a secondary seal, and has a contact pressure > 40 MPa, which can temporarily block the leakage (maintained for at least 3 pouring), avoid batch rejection caused by sealing failure, and improve the fault tolerance of the mold.

[0015] As a further optimized scheme of the present application, a manual butterfly valve for controlling the flow rate of the molten metal is installed inside the branch port, the valve stem of the manual butterfly valve extends to the outside of the base, and a scraper is installed on the edge of the valve plate, which is driven to rotate by the valve plate to remove the residual molten metal on the inner wall of the branch port at the movement track of the valve plate, preventing abnormal rotation of the valve plate. The manual butterfly valve can adjust the flow rate of the molten metal, which can not only adapt to the filling requirements of castings with different wall thicknesses, but also can be adjusted according to the delivery rate of the upper and lower gating systems to ensure uniform injection of the molten metal into the cavities of the upper and lower sand molds. The scraper rotates with the valve plate to remove the residual molten metal on the inner wall of the branch port, avoids sticking of the valve plate, and ensures accurate flow rate adjustment.

[0016] Further, the scraper is a high-temperature-resistant alloy material spring, and the scraping surface of the spring is embedded with wear-resistant ceramic pieces. The spring is made of Cr20Ni80 material to ensure that the scraper is in close contact with the inner wall of the branch port. The embedded wear-resistant ceramic pieces have a hardness of HRA90 and a service life 5 times that of metal scrapers, reducing the maintenance frequency.

[0017] The automobile planet carrier casting mold has the following beneficial effects: (1) By combining the upper sand mold, the lower sand mold and the sand core, the sand core is used to block the communication of the cavity, so that the mold can simultaneously form the upper casting and the lower casting, greatly improving the production efficiency. Moreover, by setting the thickness of the sand core to be 0.8 times the wall thickness of the casting, the linear shrinkage caused by the hot spot in the casting can be avoided. At the same time, the sprue supplies liquid to the upper and lower sand molds through the filter, and the filter removes impurities in the molten metal, reducing the shrinkage defects caused by impurities, thereby improving the casting yield. The second sealing ring is made of flexible graphite, and the third sealing ring is made of NiTiNb shape memory alloy, so that three seals are formed, under high temperature, the NiTiNb ring expands by 0.8% at 650 DEG C, the contact pressure is greater than 40MPa, and secondary sealing is formed, the leakage problem of traditional sealing parts under the washing of the metal liquid is solved, and the continuous working life of the mold is prolonged; The conical cylinder of the filter residue bucket guides the metal liquid to flow through the foam ceramic filter, can effectively intercept impurities such as oxides and sand particles, and then prevent unfiltered metal liquid from leaking through the refractory clay sealing ring, effectively reduces the content of non-metallic inclusions in the casting, and greatly improves the tensile strength of the casting; The first sealing ring is made of zirconia ceramic, the second sealing ring is made of flexible graphite, and the third sealing ring is made of NiTiNb shape memory alloy, so that three seals are formed, under high temperature, the NiTiNb ring expands by 0.8% at 650 DEG C, the contact pressure is greater than 40MPa, and secondary sealing is formed, the leakage problem of traditional sealing parts under the washing of the metal liquid is solved, and the continuous working life of the mold is prolonged; The filter residue bucket is connected with the fixed seat through a threaded cylinder, the filter and the sealing ring can be replaced separately, the single maintenance time can be shortened, the spare parts are universal, the maintenance cost can be effectively reduced, and it is especially suitable for large-batch continuous production scenes.

[0018] Additional aspects and advantages of the application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The overall structure schematic diagram of the automobile planet carrier casting mold provided by the application is shown in the figure; Figure 2 The forming schematic diagram of the upper casting and the lower casting of the automobile planet carrier casting mold provided by the application is shown in the figure; Figure 3 The cross-sectional structure schematic diagram of the sand core of the automobile planet carrier casting mold provided by the application is shown in the figure; Figure 4 The internal structure schematic diagram of the filter residue device of the automobile planet carrier casting mold provided by the application is shown in the figure; Figure 5 The cross-sectional structure schematic diagram of the conical cylinder of the automobile planet carrier casting mold provided by the application is shown in the figure; Figure 6 The structure schematic diagram of the sealing assembly of the automobile planet carrier casting mold provided by the application is shown in the figure.

[0020] BRIEF DESCRIPTION OF DRAWINGS:1, mold plate; 2, upper sand mold; 3, lower sand mold; 4, sand core; 5, sprue; 6, guide column; 7, upper casting; 8, lower casting; 9, filter residue device; 91, base; 92, cover body; 10, branch port; 11, runner; 12, filter residue barrel; 121, tapered cylinder; 122, ceramic foam filter; 123, refractory seal ring; 13, liquid inlet pipe; 14, butt joint pipe; 15, liquid supply pipe; 16, fixing seat; 17, fixing ring; 18, threaded cylinder; 19, manual butterfly valve; 20, scraper; 21, counterweight ring; 22, first seal ring; 23, second seal ring; 24, third seal ring. DETAILED DESCRIPTION

[0021] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar symbols represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application.

[0022] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0023] Please refer to Figures 1-6 The specific embodiment of the automobile planet carrier casting mold is as follows: As Figure 1 shown, the automobile planet carrier casting mold takes the mold plate 1 as the core bearing structure, realizes synchronous forming of upper and lower castings through the three-layer layout of "upper sand mold + lower sand mold + sand core", the mold plate 1 adopts HT300 gray cast iron material, 4 groups of guide columns 6 are symmetrically distributed on the upper and lower end faces, the cooperation precision with the upper and lower mold guide holes reaches H7 / g6, the guiding deviation is ≤0.1mm when the mold is closed, and the size error of the mold cavity is ensured to be controlled within ±0.3mm; Among them, the upper sand mold 2 and the lower sand mold 3 are pressed by furan resin sand, the surface of the mold cavity is treated by coating (zirconium powder content ≥80%), the roughness Ra is ≤6.3μm, the sand core 4 is located between the two, the precious sand coated sand (burning loss ≤0.1%) is pressed, the strength is ≥3.5MPa, the thickness is 0.8 times of the wall thickness of the casting (for example, when the wall thickness of the casting is 10mm, the thickness of the sand core is 8mm), the upper and lower castings are independently formed by blocking the communication of the mold cavity, and the production efficiency is improved; The sprue 5 is designed in steps, connected with the double-gating system through the filter 9 to realize the filtration and distribution of the metal liquid, and the flow rate is adjusted by the manual butterfly valve 19 to ensure that the filling time difference of the upper and lower sand molds is less than or equal to 2 seconds, and the overall production efficiency is improved by 100% compared with the traditional single mold.

[0024] Specifically, as shown in Figure 4 The filter 9 includes a base 91 and a cover 92, the base is cast by QT500-7 nodular cast iron, two independent gates 11 are processed inside, the inner wall roughness of the gate is less than or equal to 3.2 μm to reduce the flow resistance of the metal liquid, the cover 92 is locked with the base by four M10 bolts, the joint surface is sealed by asbestos rubber pad, and the temperature resistance is greater than or equal to 600°C.

[0025] Specifically, as shown in Figure 4 The gate 11 has a branch port 10, the manual butterfly valve 19 is built in the branch port 10, the valve rod extends to the outside of the base, the opening degree can be adjusted by rotating the handle to realize the continuous adjustment of the metal liquid flow rate of 0.5-2 L / s, so as to adjust the liquid injection idea of the upper and lower sand molds according to the length design of the two gates 11, which is beneficial to improve the liquid injection uniformity and avoid the formation of shrinkage, the scraper 20 at the edge of the valve plate is a Cr20Ni80 spring sheet with a thickness of 0.5 mm, Al2O3 wear-resistant ceramic pieces are embedded on the scraping surface, the hardness is HRA90, the metal liquid residue on the inner wall of the branch port can be removed by more than 95% by rotating the valve plate to avoid the valve plate from being stuck.

[0026] Specifically, as shown in Figure 4 The inside of the cover 92 is provided with a filter barrel 12, the filter barrel 12 includes a conical barrel 121, which is cast by ZG40CrNiMo, the upper end has a diameter of 100 mm, the lower end has a diameter of 50 mm, the inner wall has a taper of 15° to guide the centripetal flow of the metal liquid, the lower end is welded with a threaded barrel 18, which cooperates with the threaded hole of the fixed seat 16, the threaded connection is wrapped with graphite packing to ensure that the metal liquid does not leak.

[0027] Further, as shown in Figure 5 A foam ceramic filter 122 is installed at the bottom end of the filter barrel 12, which is made of Al2O3-ZrO2 composite material, has a pore size of 50 μm, a porosity of 80%, and a thickness of 15 mm, and is fixed to the inner wall of the conical barrel through a refractory sealing ring 12 (3Al2O3 content is greater than or equal to 70%) with a width of 10 mm, and has a strength of greater than or equal to 2 MPa after being dried at 150°C, which prevents unfiltered metal liquid from flowing through the gap.

[0028] Specifically, the upper end of the filter barrel 12 is connected with the liquid inlet pipe 13 through the butt joint pipe 14 and sealed by a sealing element, the lower end of the filter barrel 12 is connected with the adjacent gate 11, and the end of the liquid inlet pipe 13 away from the filter barrel 12 is connected with the liquid outlet of the sprue 5 through the liquid supply pipe 15; asFigure 6 As shown, the sealing member comprises The first sealing ring 22 is a hot isostatic pressing zirconia ceramic ring with a bending strength ≥800 MPa, sleeved on the lower end of the liquid inlet pipe 13 (nickel-based high-temperature alloy GH4169 material) and attached to the upper end surface of the butt joint pipe 14, with a metal liquid washing life ≥50 pouring times; The second sealing ring 23 is an O-shaped ring with a cross-section of Φ30mm×3mm made of high-purity expanded graphite (carbon content ≥99%) impregnated with phosphate, embedded in the annular sealing groove (depth 2mm) on the upper end of the butt joint pipe, and can fill the micro gap between the first sealing ring and the butt joint surface after being pressed (sealing pressure ≥0.5MPa), with an oxidation temperature resistance of up to 800℃; The third sealing ring 24 is a NiTiNb shape memory alloy ring with a phase transition temperature of 650℃, which expands axially by 0.8% after being heated, forms a secondary sealing with a contact pressure >40MPa under the pressure of the counterweight ring 21 (Q235 steel, weight 1kg), and can temporarily block the leakage (maintained for at least 3 pouring times) to avoid batch rejection.

[0029] Further, the liquid supply pipe 15 is Y-shaped structure (main pipe diameter 60mm, branch pipe diameter 40mm), the branch pipe is connected with the liquid inlet pipe 13 through flange (gasket is asbestos rubber plate), which ensures that the metal liquid distribution deviation is ≤5%, and the coaxiality of the liquid inlet pipe and the butt joint pipe 14 is ≤0.5mm, avoiding oxidation caused by turbulent flow of metal liquid.

[0030] Specifically, the process flow and operation steps of using the casting mold are as follows: S1 mold pre-installation and sand mold preparation Clean the guide column 6 and positioning surface of the mold plate 1, apply high-temperature resistant lubricating grease (drop point ≥200℃), hoist the lower sand mold 3 to the lower mold of the mold plate, put the sand core 4 into the positioning groove of the lower sand mold, then hoist the upper sand mold 2 to close the mold, and ensure that the sand core is tightly attached to the upper and lower sand molds; Then fix the base 91 to the upper end of the mold plate (positioned by positioning pins), connect the slag filter barrel 12 to the fixed seat 16 through the threaded cylinder 18 (after tightening, back off 1 / 4 turn to eliminate stress), evenly lock the bolts after the cover body 92 is buckled, and check the sealing of the liquid supply pipe 15 and the sprue 5 (red ocher powder is used to detect the attachment rate ≥90%); S2 metal liquid pouring and parameter control Use a medium-frequency induction furnace to melt ductile cast iron (QT600-3) at an outlet temperature of 1450-1500℃, after degassing (nitrogen is introduced for 10 minutes) and desulfurization (sulfur content ≤0.03%), pour through the sprue 5; The molten metal enters the filter through the supply pipe 15, forms a cyclone in the conical cylinder 121, the impurities are intercepted by the ceramic foam filter 122, and the pure molten metal is divided into the double sprue 11. The manual butterfly valve 19 is adjusted to make the filling flow rate of the upper sand mold 1.2 L / s and the lower sand mold 1.0 L / s (due to the difference in gravity compensation), to ensure that both are filled at the same time (the filling time is about 8-10 seconds); S3 Casting forming and mold maintenance After pouring, stand for 30 minutes, and open the mold when the casting temperature drops below 600℃, and use the mechanical hand to grab the casting; After every 50 times of pouring, disassemble the filter barrel 12 to replace the ceramic foam filter 122, clean the residual sand and metal tumors on the inner wall of the conical cylinder, and check the wear of the sealing ring.

[0031] It should be noted that the sand core 4 needs to be checked for strength (compressive strength ≥ 3MPa) before installation to avoid collapse during pouring; the ceramic foam filter 122 needs to be dried at 200℃ for 2 hours before use to remove moisture and prevent cracking; the handle of the manual butterfly valve 19 needs to be locked after adjustment to avoid changes in opening caused by metal liquid impact.

[0032] In one application embodiment, 400 upper and lower castings can be produced per shift of 8 hours, which is 100% higher than traditional single mold, and the wall thickness difference is ≤0.5mm; through ultrasonic flaw detection, the porosity defect rate of the casting is reduced from 18% of the traditional process to 3%, the non-metallic inclusion grade is ≤1 level (GB / T10561 standard), and the tensile strength is increased by 12% (up to 620MPa).

[0033] In summary, the mold realizes efficient and high-quality casting of the automobile planetary carrier through structural optimization, and is especially suitable for mass production scenarios, which significantly improves the reliability of the casting while reducing costs.

[0034] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An automobile planet carrier casting mold comprising a mold plate (1) disposed between an upper mold and a lower mold, characterized in that, The mold plate (1) is provided with an upper sand mold (2), a lower sand mold (3), a sand core (4), and a sprue (5). The sand core (4) is located between the upper sand mold (2) and the lower sand mold (3) and is used to block the communication between the upper sand mold (2) and the lower sand mold (3). The thickness of the sand core (4) is 0.8 times the wall thickness of the casting. The mold plate (1) is provided with a slag filter (9). The sprue (5) is connected to the cavities of the upper sand mold (2) and the lower sand mold (3) through the slag filter (9). The slag filter (9) is internally provided with a filter assembly for removing impurities from the casting metal liquid.

2. The casting mold for an automobile carrier according to claim 1, wherein The slag filter (9) includes a base (91) installed on the upper end of the mold plate (1) and a cover body (92) detachably installed on the upper end of the base (91). The base (91) has two independent runners (11) inside. One end of the runner (11) has a branch opening (10) located outside the base (91), and the two branch openings (10) are respectively connected to the cavities of the upper sand mold (2) and the lower sand mold (3). The other end of the runner (11) extends to the upper end of the base (91) and is connected to the liquid outlet of the sprue (5) through the filter assembly.

3. The casting mold for an automobile carrier according to claim 2, wherein The filter assembly includes a slag bucket (12) detachably installed on the upper end of the base (91) and a liquid inlet pipe (13) installed on the upper end of the cover body (92). The upper end of the slag bucket (12) is connected to the liquid inlet pipe (13) through a butt joint pipe (14) and is sealed by a sealing element. The lower end of the slag bucket (12) is connected to the adjacent runner (11). The end of the liquid inlet pipe (13) away from the slag bucket (12) is connected to the liquid outlet of the sprue (5) through a liquid supply pipe (15).

4. The casting mold for an automobile carrier according to claim 3, wherein The slag bucket (12) includes a tapered cylinder (121) with a larger upper diameter than a lower diameter. The upper end of the tapered cylinder (121) is fixedly connected to the lower end of the butt joint pipe (14). The lower end of the tapered cylinder (121) is detachably connected to the upper end of the base (91) and is connected to the adjacent runner (11). A foamed ceramic filter (122) is installed inside the lower end of the tapered cylinder (121). The gap between the foamed ceramic filter (122) and the inner wall of the tapered cylinder (121) is sealed by a refractory mud seal ring (123).

5. The casting mold for an automobile carrier according to claim 4, wherein The upper end of the base (91) is provided with a fixing seat (16) having a threaded hole. The end of the runner (11) away from the branch opening (10) extends upward and is connected to the lower end of the threaded hole. The diameter of the threaded hole is larger than the diameter of the runner (11). The lower end of the tapered cylinder (121) is provided with a threaded cylinder (18) corresponding to and matching the threaded hole. The lower end of the threaded cylinder (18) is threadedly connected to the threaded hole and is sealed.

6. The casting mold for an automobile carrier according to claim 3, wherein The sealing element includes a counterweight ring (21) and a first sealing ring (22). The first sealing ring (22) is a hot isostatic pressing zirconia ceramic ring. The butt joint pipe (14) is a nickel-based high-temperature alloy pipe. The counterweight ring (21) is fixedly sleeved on the lower end of the liquid inlet pipe (13) and is pressed on the butt joint pipe (14). The first sealing ring (22) is sleeved on the liquid inlet pipe (13) and is located between the counterweight ring (21) and the butt joint pipe (14).

7. The casting mold for an automobile carrier according to claim 6, wherein The sealing member further comprises a second sealing ring (23), which is a flexible graphite ring formed by impregnating a phosphate with high-purity expanded graphite, an annular sealing groove is formed in the upper end surface of the butt joint pipe (14) and is centrally arranged, and the second sealing ring (23) is arranged in the annular sealing groove; a groove corresponding to and matching the second sealing ring (23) is formed in the lower end surface of the first sealing ring (22), and the second sealing ring (23) seals the gap between the contact surface of the first sealing ring (22) and the butt joint pipe (14).

8. The casting mold for an automobile carrier according to claim 6, wherein The sealing member further comprises a third sealing ring (24), which is arranged between the counterweight ring (21) and the first sealing ring (22) and is a shape memory alloy ring made of NiTiNb; when the first sealing ring (22) fails, the NiTiNb ring is activated at high temperature to expand and form a secondary mechanical seal.

9. The casting mold for an automobile carrier according to claim 2, wherein A manual butterfly valve (19) for controlling the flow rate of the molten metal is mounted in the branch port (10), the valve rod of the manual butterfly valve (19) extends to the outside of the base (91), and a scraper (20) is mounted on the edge of the valve plate of the manual butterfly valve (19); the valve plate drives the scraper (20) to rotate to remove the residual molten metal on the inner wall of the branch port (10) at the movement track of the valve plate.

10. The casting mold for an automobile carrier according to claim 9, wherein The scraper (20) is a high-temperature-resistant alloy elastic sheet, and the scraping surface of the elastic sheet is embedded with wear-resistant ceramic sheets.

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