Pouring system for front end cover of engine

Abstract

The utility model discloses a pouring system of an engine front end cover, which is characterized in that the left side and the right side of the upper end of a central rotating shaft hole on a large plane of a casting main body are respectively connected with a left arm rotating shaft hole, a right arm rotating shaft hole, a left arm large mounting flange and a right arm large mounting flange, and the other end of the central rotating shaft hole is connected with an integrally concave thin-wall area gear shaft box; a gear shaft box oil way inlet is formed in the center of the gear shaft box; the periphery of the upper end of the center pouring gate is connected with a plurality of first-layer supporting cross gates which extend outwards in a radial shape, and the tops, close to the outer end, of the first-layer supporting cross gates are connected with the second-layer water inlet cross gates through first-layer water inlets to form a double-pouring-gate system; and the second-layer water inlet cross gate forms an annular shape below the areas of the left arm rotating shaft hole, the left arm large mounting flange, the right arm rotating shaft hole and the right arm large mounting flange and is connected with the bottom of the engine front end cover through a plurality of second-layer water inlets. The pouring requirements of thick and large parts and thin walls can be met at the same time, sequential solidification is achieved, feeding is reliable, and quality is high.

Description

Technical Field

[0001] This utility model relates to magnesium alloy casting, and more particularly to a gating system for an engine front cover, belonging to the technical field of complex casting process. Background Technology

[0002] Currently in China, the vast majority of engine front cover products are made of aluminum alloy, with very few front covers made of high-performance heat-resistant rare-earth magnesium alloy. As the requirements for aircraft lightweighting become increasingly stringent, the application of magnesium alloy engine front covers is also growing. Therefore, it is urgent to research a casting process for a large, high-performance heat-resistant rare-earth magnesium alloy engine front cover with thin walls, complex oil passages, large flat surfaces, and irregular shapes.

[0003] The engine front cover casting includes a central pivot hole on the large flat surface of the main body of the casting, which is the thickest part of the casting. It is difficult to compensate for shrinkage and solidifies slowly. Two large mounting flanges and connecting shaft holes are respectively connected to the upper left and right sides of the central pivot hole. The other end of the central pivot hole is connected to an integrally recessed gear shaft housing. The overall outline length exceeds 1300mm, the width exceeds 800mm, and the thickness exceeds 250mm. The side wall of the large flat surface of the front cover is provided with an observation port connecting flange.

[0004] The side walls of the engine front cover are predominantly thin-walled. Due to the poor fluidity and low density of magnesium alloy, and the low pouring temperature, it is difficult to cast the thin-walled sections. Excessive solidification speed can easily lead to casting defects such as porosity, looseness, inclusions, and incomplete filling. Conversely, high pouring temperatures can cause porosity, hot cracking, and shrinkage cavities in the thin-walled sections, resulting in a low yield. Furthermore, excessive differences in the solidification time of the molten metal can cause thermal stress in the casting after solidification, leading to deformation, cracks, and defects such as shrinkage cavities and porosity.

[0005] The engine front cover features two oil passages around the central pivot hole at the center of the bottom plane and the two large mounting flanges connected to the connecting shaft holes on the upper left and right sides. The oil passage around the central pivot hole is a 36mm*13mm flat pipe, over 1.4 meters long, requiring high quality and presenting significant casting challenges. The oil passage around the large mounting flanges and connecting shaft holes is a φ12 oil passage, over 1.6 meters long. Due to its thinness, length, and tortuous nature, the passage lacks sufficient strength and is prone to deformation or even breakage during casting. Both oil passages have complex shapes, a total length exceeding 3 meters, and an overall wall thickness of 4-6mm, making the oil passage structure difficult to form and cleaning. In short, the engine front cover demands high-quality casting equipment and processes, resulting in significant casting difficulties. Utility Model Content

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0007] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0008] The purpose of this invention is to overcome the problems existing in the prior art and provide a casting system for the front cover of an engine that can simultaneously meet the casting requirements of both thick and thin-walled parts of the front cover, achieve sequential solidification of the casting, ensure reliable feeding and avoid incomplete casting, and improve the quality of the casting.

[0009] To solve the above technical problems, this utility model provides a casting system for an engine front cover. The engine front cover includes a large flat surface of the casting body. A central pivot hole 1a is provided on the large flat surface of the casting body. A left arm pivot hole 1b1 and a left arm large mounting flange 1c1 are connected to the left side of the upper end of the central pivot hole 1a. A right arm pivot hole 1b2 and a right arm large mounting flange 1c2 are connected to the right side of the upper end of the central pivot hole 1a. The other end of the central pivot hole 1a is connected to a gear shaft housing 1d1 with an integrally recessed thin-walled area. A gear shaft housing oil inlet 1d2 is provided at the center of the gear shaft housing 1d1.

[0010] The upper outer periphery of the center gate 2 is connected to multiple radially extending first-layer support horizontal runners 3. The top of the first-layer support horizontal runners 3 near the outer end is connected to the second-layer water inlet horizontal runners 5 through the first-layer water inlet 4, forming a double runner system. The second-layer water inlet horizontal runners 5 form a ring below the areas of the left arm pivot hole 1b1, the left arm large mounting flange 1c1, the right arm pivot hole 1b2, and the right arm large mounting flange 1c2, and are connected to the bottom of the engine front cover through multiple second-layer water inlets 6.

[0011] Furthermore, a left suspension oil inlet 1e1 is provided between the left arm large mounting flange 1c1 and the gear shaft box 1d1, and a right suspension oil inlet 1e2 is provided between the right arm large mounting flange 1c2 and the gear shaft box 1d1. An observation port connecting flange 1f is provided on the outer side wall of the left suspension oil inlet 1e1. An oil passage 1g is provided on the outer periphery of the central rotating shaft hole 1a, and the oil passage 1g connects the central rotating shaft hole 1a and the gear shaft box oil inlet 1d2.

[0012] Furthermore, the outer side of the second-layer water inlet horizontal gating channel 5 is connected to an upwardly extending side passage cylinder 8, which is connected to the second-layer water inlet horizontal gating channel 5 and connected to the outer side of the casting through a side water inlet 9.

[0013] The center of the second layer of water inlet horizontal pouring channel 5 is connected to an upwardly extending central through cylinder 14, and the outer periphery of the central through cylinder 14 is connected to the inner peripheral wall of the central rotating shaft hole 1a through multiple central water inlets.

[0014] Furthermore, the top center of the central pivot hole 1a is provided with an upwardly extending vent groove 12, and the upper openings of the thicker parts, such as the left arm pivot hole 1b1, the left arm large mounting flange 1c1, the right arm pivot hole 1b2, and the right arm large mounting flange 1c2, are provided with flange risers 11; the outer wall of the central pivot hole 1a is provided with a boss, and the second layer of water inlet horizontal gating channel 5 is connected to the boss through a dotted gating gate 7.

[0015] Compared with existing technologies, this utility model achieves the following beneficial effects: 1. The low-pressure dual-sprue casting process enables uniform temperature distribution within the sand mold, avoiding localized overheating and ensuring smooth feeding of the casting. After the molten magnesium fills the first supporting runner, the oxide inclusions generated during filling remain at the end of the runner and do not flow into the second water-inlet runner. The molten magnesium fills the mold uniformly in the second water-inlet runner, preventing backflow of the first-filled area into the runner due to its excessive length, thus avoiding defects such as air entrapment and inclusions. During low-pressure casting, the flow rate of the molten magnesium is controllable, flowing under pressure, improving filling capacity, providing stable and adjustable flow rate and pressure, resulting in a denser internal structure free from porosity and shrinkage defects.

[0016] 2. The gear shaft housing on the bottom plane of the end cover and the area of ​​the large mounting flanges and connecting shafts on the upper left and right sides are thick sections. Water inlets along their own circumferential walls are provided for direct water intake to compensate for shrinkage and ensure the internal quality of the thick sections. The dual-runner system allows for directional filling of different areas, optimizing shrinkage compensation in thick sections. Water inlets along their own circumferential walls are provided in the thick sections, with the lower end of each inlet connected to a corresponding horizontal runner. The middle section of each horizontal runner is connected to the circumferential walls of the large mounting flanges and connecting shafts via multiple radial runners. Multiple inlets can disperse heat and reduce defects caused by overheating. Water intake through the second layer of horizontal runners ensures the internal quality of the thick sections.

[0017] 3. An observation port connecting flange is provided with a passage cylinder on the outside of which is connected to the second layer of water inlet horizontal runner. The observation port connecting flange and the passage cylinder are connected through the inner gate. The inner gate directly fills the mold, which improves the filling rate of thin-walled parts and prevents insufficient filling due to excessive solidification in thin-walled areas. The point gate provides feeding for local hot spots such as bosses, and adjusts the temperature distribution and solidification sequence of the casting.

[0018] 4. The integral gating system of the casting achieves sequential solidification, giving full play to the feeding function of the gating and riser, reducing the formation of porosity and shrinkage cavities, and improving the internal quality of the casting; at the same time, chills are also set to cool the hot parts, improve the feeding capacity of the hot parts, and reduce the generation of porosity and shrinkage cavities. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit this utility model. Wherein:

[0020] Figure 1 This is a schematic diagram of the structure of the engine front cover casting in this utility model;

[0021] Figure 2 This is a perspective view of the casting system in this utility model;

[0022] Figure 3 This is a bottom view of the casting system in this utility model;

[0023] Figure 4 This is a structural diagram of the casting after it has been cast in this utility model.

[0024] Figure 5 This is a layout diagram of the cooling iron in this utility model;

[0025] Figure 6 This is a schematic diagram of the segmented structure of the curved, slender oil passage sand core in this utility model;

[0026] Figure 7 This is a cross-sectional view of the curved, slender oil passage sand core of this utility model;

[0027] In the diagram: Engine front cover casting: 1a. Central pivot hole; 1b1. Left arm pivot hole; 1b2. Right arm pivot hole; 1c1. Left arm large mounting flange; 1c2. Right arm large mounting flange; 1d1. Gear shaft housing; 1d2. Gear shaft housing oil inlet; 1e1. Left suspension oil inlet; 1e2. Right suspension oil inlet; 1f. Observation port connecting flange; 1g. Oil passage;

[0028] 2. Center gate; 3. First-layer support runner; 4. First-layer inlet; 5. Second-layer inlet runner; 6. Second-layer inlet; 7. Point gate; 8. Side gating; 9. Side inlet; 10. Center riser; 11. Flange riser; 12. Venting groove; 13. Open riser; 14. Center gating; 15. Chip;

[0029] 16. Curved and slender oil passage sand core; 16a. Half tenon; 16b. Oil passage positioning gap;

[0030] 17. Curved and slender oil passage sand core support column; 18. Curved and slender oil passage vent hole; 19. Oil passage sand core positioning pin;

[0031] 20. Bottom shape; 20a. Oil channel sand core positioning groove; 20b. Process hole positioning gap. Detailed Implementation

[0032] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0033] like Figures 1 to 5 As shown, in this utility model, the engine front cover includes a central pivot hole 1a on the large flat surface of the casting body. A left arm pivot hole 1b1 and a left arm large mounting flange 1c1 are connected to the left side of the upper end of the central pivot hole 1a. A right arm pivot hole 1b2 and a right arm large mounting flange 1c2 are connected to the right side of the upper end of the central pivot hole 1a. The other end of the central pivot hole 1a is connected to a gear shaft housing 1d1, which is a thin-walled area with an integrally recessed design. A gear shaft housing oil inlet 1d2 is located at the center of the gear shaft housing 1d1. The left arm pivot hole 1b1, the left arm large mounting flange 1c1, and the right arm pivot hole 1b2, the right arm large mounting flange 1c2 are symmetrically arranged around the central axis of the casting.

[0034] A left-side oil inlet 1e1 is provided between the left-side large mounting flange 1c1 and the gear shaft housing 1d1, and a right-side oil inlet 1e2 is provided between the right-side large mounting flange 1c2 and the gear shaft housing 1d1. The left-side and right-side oil inlets 1e1 and 1e2 are symmetrically arranged around the central axis of the casting. An observation port connecting flange 1f is provided on the outer wall of the left-side oil inlet 1e1; an oil passage 1g is provided on the outer periphery of the central shaft hole 1a, connecting the central shaft hole 1a and the gear shaft housing oil inlet 1d2.

[0035] Below the central pivot hole 1a, there is a central gate 2 coaxial with it. The upper outer periphery of the central gate 2 is connected to multiple first-layer support horizontal runners 3 that extend outward in a radial pattern. The top of the first-layer support horizontal runners 3 near the outer end is connected to the second-layer water inlet horizontal runner 5 through the first-layer water inlet 4, forming a double runner system.

[0036] The second-layer water inlet horizontal gating channel 5 forms a ring below the areas of the left arm pivot hole 1b1, the left arm large mounting flange 1c1, the right arm pivot hole 1b2, and the right arm large mounting flange 1c2, and is connected to the bottom of the engine front cover through multiple second-layer water inlets 6.

[0037] The outer side of the second-layer water inlet horizontal sprue 5 is connected to an upwardly extending side passage cylinder 8. The side passage cylinder 8 is connected to the second-layer water inlet horizontal sprue 5 and is connected to the outer side of the casting through the side water inlet 9.

[0038] The center of the second-layer horizontal water inlet channel 5 is connected to an upwardly extending central passage cylinder 14. The outer periphery of the central passage cylinder 14 is connected to the inner peripheral wall of the central pivot hole 1a through multiple central water inlets. The top center of the central pivot hole 1a is provided with an upwardly extending vent groove 12. The upper openings of the thicker parts, such as the left arm pivot hole 1b1, the left arm large mounting flange 1c1, the right arm pivot hole 1b2, and the right arm large mounting flange 1c2, are provided with flange risers 11.

[0039] The outer wall of the central pivot hole 1a is provided with a boss. Since it is close to the oil passage 1g, the second layer water inlet horizontal runner 5 is connected to the boss through the dot gate 7, and the boss is filled separately through the dot gate 7.

[0040] Molten magnesium alloy enters through the central gate 2 and then flows radially outward along each of the first-layer supporting transverse runners 3. After filling the first-layer supporting transverse runners 3, the molten magnesium alloy reaches the second-layer water inlet transverse runner 5 through the first-layer inlet 4. After the first-layer supporting transverse runners 3 are filled, the oxide inclusions generated during filling remain at the end of the transverse runners and do not flow into the second-layer water inlet transverse runners. After the molten magnesium alloy uniformly fills the second-layer water inlet transverse runners 5, it enters the mold cavity through the second-layer inlet 6 and the dot gate 7, filling the mold cavity of the engine front cover from bottom to top. Because the molten magnesium alloy fills the mold uniformly in the second-layer water inlet runners, the molten magnesium alloy entering the mold cavity avoids the situation where the molten magnesium alloy from the first water-filled area flows back into the transverse runners due to the transverse runners being too long, thus preventing defects such as air entrapment and inclusions.

[0041] Since the central pivot hole 1a is the thickest, the molten magnesium alloy also flows along the central tube 14 and then through the central inlet to fill the side wall of the central pivot hole 1a. Three upward-extending venting grooves 12 are evenly distributed on the top of the circumferential wall of the central pivot hole 1a to discharge the gas generated during casting.

[0042] The magnesium alloy liquid entering the engine front cover cavity rises evenly from the bottom, filling the thick parts such as the left arm large mounting flange 1c1 and the right arm large mounting flange 1c2, and then continues to enter the flange riser 11, which replenishes the thick parts such as the left arm large mounting flange 1c1 and the right arm large mounting flange 1c2.

[0043] Because the gear shaft housing 1d1 is primarily thin-walled, filling it sequentially from bottom to top can easily lead to defects such as insufficient filling. Therefore, multiple second-layer inlets 6 are installed on the side walls and bottom plane of the gear shaft housing 1d1. Molten magnesium alloy reaching the first-layer supporting runner 3 enters the second-layer inlet runner 5 through the first-layer inlet 4. After filling the second-layer inlet runner 5, the molten magnesium alloy flows upwards through the second-layer inlets 6 into the cavity of the gear shaft housing 1d1. After filling, the molten magnesium alloy enters through the risers 13, and the top of the gear shaft housing 1d1 is fed back through each riser 13. During the filling process, water vapor generated from the reaction of cold air in the sand mold, as well as gases generated by the protective agent to prevent the molten magnesium alloy from burning, are discharged through each riser 13.

[0044] The outer side of the observation port connecting flange 1f is provided with upwardly extending side passage cylinders 8. The side passage cylinders 8 are connected to the second layer of water inlet horizontal pouring channel 5. After the magnesium alloy liquid fills the side passage cylinders 8, it is then replenished through two side water inlets 9 to the observation port connecting flange 1f.

[0045] The area between the top of the gear shaft housing 1d1 and the left arm shaft hole 1b1 and the right arm shaft hole 1b2, as well as the boss, are provided with multiple upward-extending central risers 10 for feeding the top boss and the flange below it.

[0046] Chips 15 are placed at the thick and hot joints of the central pivot hole 1a, the left arm pivot hole 1b1, and the right arm pivot hole 1b2, respectively, to accelerate the cooling speed of the thick and hot joints, make the solidification process more uniform, and reduce stress concentration caused by asynchronous solidification.

[0047] like Figure 6 , Figure 7 As shown, the outer periphery of the left arm large mounting flange 1c1 and the right arm large mounting flange 1c2 is provided with a curved and slender oil passage sand core 16. The inner diameter of the curved and slender oil passage is 12mm, the wall thickness is 4-6mm, and the length is more than 1.6m. The head end of the curved and slender oil passage sand core 16 is connected to the side wall oil hole of the left arm large mounting flange 1c1, the right arm large mounting flange 1c2, the left arm pivot hole 1b1, and the right arm pivot hole 1b2; the end of the curved and slender oil passage sand core 16 is connected to the side wall oil hole of the central pivot hole 1a.

[0048] The curved and slender oil passage sand core 16 uses each oil outlet as a support column, including a curved and slender oil passage sand core support 17. The lower end of each oil passage sand core support column is provided with an oil passage sand core positioning pin 19. Each oil passage sand core positioning pin 19 has a conical structure and is respectively embedded in the corresponding oil passage sand core positioning groove 20a of the bottom 20.

[0049] Multiple curved and slender oil passage vent holes 18 are provided along the length of the curved and slender oil passage sand core 16. The 3D printed oil passage sand core can have vent holes set inside the sand core along its axis to prevent the problem of air blockage caused by the inability to vent due to the oil passage being too long.

[0050] Each oil circuit sand core positioning pin 19 and the corresponding oil circuit sand core positioning groove 20a are respectively provided with process hole positioning gaps 20b, each process hole positioning gap 20b is 0.3mm, to ensure the accuracy of the oil circuit assembly dimensions. After the oil circuit is assembled, paint is used to fill all gap positions by brushing.

[0051] The slender oil passage sand core is disassembled into multiple short oil passage sand cores, each 300-400mm in length. Each oil passage sand core is positioned via an oil port, effectively reducing structural deformation during casting. Positioning is provided between adjacent oil passage sand core segments with a 0.3mm gap, and a 0.3mm gap is also provided between the oil passage process hole positioning and the sand mold positioning to ensure the accuracy of the oil passage assembly dimensions. After assembly, all gaps are filled with a coating to reduce the formation of imperfections such as burrs and casting nodules within the casting's oil passages, reducing flow resistance and facilitating sand removal. Internal oil passages connected to each lubrication point are integrated within the casting, significantly reducing external oil passages, improving engine reliability, and reducing weight.

Claims

1. A casting system for an engine front cover, characterized in that, The engine front cover includes a large flat surface of the casting body. A central pivot hole (1a) is provided on the large flat surface of the casting body. A left arm pivot hole (1b1) and a left arm large mounting flange (1c1) are connected to the left side of the upper end of the central pivot hole (1a). A right arm pivot hole (1b2) and a right arm large mounting flange (1c2) are connected to the right side of the upper end of the central pivot hole (1a). The other end of the central pivot hole (1a) is connected to a gear shaft housing (1d1) with an integrally recessed thin-walled area. A gear shaft housing oil inlet (1d2) is provided in the center of the gear shaft housing (1d1). The upper outer periphery of the center gate (2) is connected to multiple radially extending first-layer support horizontal runners (3). The top of the first-layer support horizontal runners (3) near the outer end is connected to the second-layer water inlet horizontal runners (5) through the first-layer water inlet (4) to form a double runner system. The second-layer water inlet horizontal runners (5) form a ring below the areas of the left arm pivot hole (1b1), the left arm large mounting flange (1c1), the right arm pivot hole (1b2), and the right arm large mounting flange (1c2) and are connected to the bottom of the engine front cover through multiple second-layer water inlets (6).

2. The casting system for the engine front cover according to claim 1, characterized in that, A left-side oil passage inlet (1e1) is provided between the left arm large mounting flange (1c1) and the gear shaft box (1d1), and a right-side oil passage inlet (1e2) is provided between the right arm large mounting flange (1c2) and the gear shaft box (1d1). An observation port connecting flange (1f) is provided on the outer side wall of the left-side oil passage inlet (1e1); an oil passage (1g) is provided on the outer periphery of the central rotating shaft hole (1a), and the oil passage (1g) connects the central rotating shaft hole (1a) and the gear shaft box oil passage inlet (1d2).

3. The casting system for the engine front cover according to claim 1, characterized in that, The outer side of the second layer water inlet horizontal gating channel (5) is connected to an upwardly extending side passage cylinder (8), which is connected to the second layer water inlet horizontal gating channel (5) and connected to the outer side of the casting through the side water inlet (9); The center of the second layer water inlet horizontal pouring channel (5) is connected to an upwardly extending central through cylinder (14), and the outer periphery of the central through cylinder (14) is connected to the inner peripheral wall of the central rotating shaft hole (1a) through multiple central water inlets.

4. The casting system for the engine front cover according to claim 1, characterized in that, The central pivot hole (1a) has an upwardly extending vent groove (12) at its top center. The upper openings of the thick-part left arm pivot hole (1b1), left arm large mounting flange (1c1), right arm pivot hole (1b2), and right arm large mounting flange (1c2) are provided with flange risers (11). The outer wall of the central pivot hole (1a) is provided with a boss. The second layer of water inlet horizontal gating channel (5) is connected to the boss through a point-shaped gating gate (7).

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