A negative pressure die casting device for exhaust manifolds

Abstract

This application relates to the field of casting technology, and in particular to a negative pressure die casting device for exhaust manifolds, comprising a work frame, a housing, a sand mold, and a casting block. The housing is connected to the work frame, and both the sand mold and the casting block are disposed within the housing. The sand mold is slidably connected to the work frame in a vertical direction. The casting block has pores and is covered with a thermoplastic film. The sand mold and the casting block are spaced apart in a vertical direction, forming a cavity for the exhaust manifold casting within the housing. An injection pipe is disposed on the housing and communicates with the cavity. A first vacuum assembly is connected to the casting block, and a second vacuum assembly is connected to the sand mold. The casting block is hollow. The first vacuum assembly includes an air bladder and an air pump, both of which are disposed within the casting block. The air pump is connected to the air bladder. This application has the effect of improving the casting quality of exhaust manifolds.

Description

Technical Field

[0001] This application relates to the field of casting technology, and in particular to a negative pressure die casting device for an exhaust manifold. Background Technology

[0002] The exhaust manifold is connected to the engine cylinder block, which collects the exhaust from each cylinder and directs it into the main exhaust pipe. It has branching pipes.

[0003] Currently, most austenitic heat-resistant cast steel exhaust manifolds are produced using the traditional gravity casting process. This involves injecting molten metal into a mold, where the molten metal is formed under its own weight. Since exhaust manifolds are typically thin-walled and complex castings, this casting method results in the exhaust manifolds requiring numerous and large risers for feeding, leading to poor quality. Summary of the Invention

[0004] To improve the casting quality of exhaust manifolds, this application provides a negative pressure die casting device for exhaust manifolds.

[0005] The exhaust manifold negative pressure die-casting device provided in this application adopts the following technical solution:

[0006] An exhaust manifold negative pressure die casting device includes a work frame, a housing, a sand mold, and a casting block. The housing is connected to the work frame. The sand mold and the casting block are both disposed within the housing. The sand mold is slidably connected to the work frame in a vertical direction. The casting block has air holes and is covered with a thermoplastic film. The sand mold and the casting block are spaced apart in a vertical direction, forming a cavity for an exhaust manifold casting within the housing. An injection pipe is disposed on the housing and communicates with the cavity. A first vacuum assembly is connected to the casting block, and a second vacuum assembly is connected to the sand mold. The casting block is hollow. The first vacuum assembly includes an air bladder and an air pump. The air pump and the air bladder are both disposed within the casting block, and the air pump is connected to the air bladder.

[0007] By adopting the above technical solution, the mold block is heated and the mold block is evacuated by the second vacuum assembly, so that the thermoplastic film adheres tightly to the mold block. The sand mold is moved so that a cavity is formed between the sand mold and the mold block. The molten metal is injected into the cavity through the injection pipe, and the exhaust manifold is cast by negative pressure casting. The exhaust manifold produced in this way has a smooth surface and clear outline, which improves the casting quality of the exhaust manifold. The air pump draws the air in the mold block into the air bag. The main air bag and the air pump are used to evacuate the mold block. The air pump and the air bag are set inside the mold block, thus saving space.

[0008] Optionally, the sand mold includes a sand box filled with gravel, the opening of the sand box away from the casting block is covered with a sealing film, and a sand scraping assembly is connected to the sand box.

[0009] By adopting the above technical solution, the sand box is placed on the mold block, and sand is injected into the sand box. The sand fills the sand box according to the shape of the mold block. The sand scraping component makes it easy to scrape the sand in the sand box, thereby improving the compactness of the sand in the sand box. After scraping the sand, the sealing film is covered on the sand box, and the second vacuum component is used to evacuate the sand box to remove the air in the sand box, thereby increasing the density of the sand in the sand box and completing the production of the sand mold.

[0010] Optionally, the sand box is slidably connected to the work frame in a vertical direction. The sand box is provided with two dovetail grooves, each with a dovetail-shaped cross-section. One end of each dovetail groove penetrates the side wall of the sand box near the ground, while the distance between the other end and the side wall of the sand box near the ground varies. A dovetail block is detachably connected to the sand box. The dovetail block is located within the dovetail groove and slides in cooperation with it. A connecting strip is connected to the end of the dovetail block away from the bottom of the dovetail groove. The box body is provided with a connecting groove corresponding to the dovetail groove. The connecting groove penetrates the side wall of the box body away from the ground, and the connecting strip is inserted into the connecting groove and slides in cooperation with it.

[0011] By adopting the above technical solution, the dovetail block is placed in the longer dovetail groove, and the sand box is moved vertically. The connecting strip is inserted into the connecting groove until the dovetail block and the dovetail groove abut against the side wall away from the ground, and the connecting strip abuts against the side wall of the connecting groove near the ground. At this time, the sand box abuts against the casting block and is located above the casting block, which facilitates the production of sand molds. The dovetail block is placed in the shorter dovetail groove, and the sand box is moved vertically. The connecting strip is inserted into the connecting groove until the dovetail block and the dovetail groove abut against the side wall away from the ground, and the connecting strip abuts against the side wall of the connecting groove near the ground. At this time, the sand mold and the casting block are set alternately. The cooperation of the dovetail groove, the dovetail block, the connecting strip and the connecting groove provides a limit to the displacement of the sand mold, thereby improving the accuracy of the cavity.

[0012] Optionally, the sand scraping assembly includes a lead screw and a scraper, the lead screw being rotatably connected to the inner wall of the sand box, the scraper being threadedly connected to the lead screw, and the side wall of the scraper abutting against the side wall of the sand box.

[0013] By adopting the above technical solution, rotating the lead screw causes the scraper to move along the length of the lead screw, thereby leveling the sand and gravel in the sand box.

[0014] Optionally, a pressure plate is slidably connected to the work frame, and the pressure plate is slidably engaged with the inner wall of the sand box.

[0015] By adopting the above technical solution, the pressure plate is moved vertically and pressed into the sand box, which compacts the sand and gravel in the sand box, thereby improving the compactness of the sand and gravel in the sand box.

[0016] Optionally, the inner wall of the sand box is provided with an avoidance groove corresponding to the scraper, and the inner wall of the sand box is provided with an installation groove, with the lead screw located in the installation groove.

[0017] By adopting the above technical solution, after the scraper flattens the gravel, the scraper is located in the clearance groove, thereby reducing the possibility of mutual interference between the pressure plate and the scraper, screw rod and guide rod, and improving the compaction effect of the pressure plate on the gravel.

[0018] Optionally, the sand box is open at both ends, and a thermoplastic film is also connected to the end of the sand box near the mold block.

[0019] By adopting the above technical solution, when making the sand mold, the sand box is placed on the casting block, and sand is injected into the sand box. The sand falls onto the thermoplastic film, and the thermoplastic film deforms according to the shape of the casting block. Both the thermoplastic film and the sand fill the sand box according to the casting block. After casting is completed, the vacuum state in the casting block and the sand box is released by the first vacuum assembly and the second vacuum assembly, and the sand returns to a flowing state. The setting of the thermoplastic film reduces the possibility of sand flowing out of the sand box.

[0020] Optionally, heating wires are connected to both the casting block and the sand box.

[0021] By adopting the above technical solution, the heating wire facilitates uniform heating of the thermoplastic film.

[0022] In summary, this application includes at least one of the following beneficial technical effects:

[0023] 1. The mold block is heated and evacuated using a second vacuum assembly, causing the thermoplastic film to adhere tightly to the mold block. The sand mold is moved to form a cavity between the sand mold and the mold block. Molten metal is injected into the cavity through the injection pipe, and the exhaust manifold is cast using negative pressure casting. This method produces an exhaust manifold with a smooth surface and clear outline, improving the casting quality of the exhaust manifold. An air pump draws air from inside the mold block into an air bladder. The main air bladder and air pump are used to evacuate the mold block. The air pump and air bladder are located inside the mold block, thus saving space.

[0024] 2. Place the sand box on the mold block and pour sand into the sand box. The sand fills the sand box according to the shape of the mold block. The sand scraping component makes it easy to scrape the sand in the sand box, thereby improving the compactness of the sand in the sand box. After scraping the sand, cover the sand box with a sealing film and use the second vacuum component to evacuate the sand box to remove the air in the sand box, thereby increasing the density of the sand in the sand box and completing the production of the sand mold.

[0025] 3. Place the dovetail block in the longer dovetail groove, move the sand box vertically, insert the connecting strip into the connecting groove until the dovetail block and dovetail groove abut against the side wall away from the ground, and the connecting strip abuts against the side wall of the connecting groove near the ground. At this point, the sand box abuts against the casting block and is located above the casting block, which facilitates the making of the sand mold. Place the dovetail block in the shorter dovetail groove, move the sand box vertically, insert the connecting strip into the connecting groove until the dovetail block and dovetail groove abut against the side wall away from the ground, and the connecting strip abuts against the side wall of the connecting groove near the ground. At this point, the sand mold and casting block are spaced apart, and the cooperation of the dovetail groove, dovetail block, connecting strip and connecting groove provides a limit to the displacement of the sand mold, thereby improving the accuracy of the cavity. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the overall structure of an exhaust manifold negative pressure die-casting device.

[0027] Figure 2 It is a schematic diagram used to illustrate the positional relationship between the mold block and the air bladder;

[0028] Figure 3 It is a schematic diagram used to illustrate the positional relationship between the slide rail and the slider;

[0029] Figure 4 It is a schematic diagram used to illustrate the positional relationship between the mounting groove and the lead screw.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Work frame; 2. Housing; 3. Casting block; 4. Air vent; 5. Thermoplastic film; 6. Airbag; 7. Air pump; 8. Sand box; 9. Sealing film; 10. Screw; 11. Gear; 12. Chain; 13. Turbine; 14. Worm gear; 15. Motor; 16. Dovetail groove; 17. Dovetail block; 18. Connecting groove; 19. Connecting strip; 20. Slide groove; 21. Slide bar; 22. Bolt; 23. Transmission pipe; 24. Reducer; 25. Cylinder; 26. Pressure plate; 27. Injection pipe; 28. Mounting groove; 29. ​​Clearance groove; 30. Scraper; 31. Lead screw. Detailed Implementation

[0032] This application discloses an exhaust manifold negative pressure die casting device.

[0033] Reference Figure 1 An exhaust manifold negative pressure die casting device includes a work frame 1, on which a housing 2 is connected.

[0034] Reference Figure 1 and Figure 2The bottom of the housing 2 is provided with a casting block 3, which is hollow and has air holes 4. A heating wire is connected to the casting block 3, and a thermoplastic film 5 is covered on the casting block 3. A first vacuum assembly is provided inside the casting block 3. The first vacuum assembly includes an air bag 6 and an air pump 7. Both the air pump 7 and the air bag 6 are located inside the casting block 3, and the air pump 7 is connected to the air bag 6.

[0035] The casting block 3 is heated by heating wire, the thermoplastic film 5 softens, and the air pump 7 in the first vacuum assembly is started. The air pump 7 draws the air in the casting block 3 into the air bag 6, and the thermoplastic film 5 adheres tightly to the casting block 3.

[0036] Reference Figure 1 and Figure 3 The side wall of the housing 2 is provided with a sliding groove 20, and a sliding strip 21 is connected to the casting block 3. The sliding strip 21 is inserted into the sliding groove 20 and slides in cooperation with the sliding groove 20. A bolt 22 is threadedly connected to the housing 2. The bolt 22 passes through the housing 2 and is connected to the sliding strip 21.

[0037] Reference Figure 2 and Figure 4 A sand mold is slidably connected to the work frame 1. The sand mold includes a sand box 8 and a sealing membrane 9. Two sets of sand scraping components are connected to the sand box 8. The two sets of sand scraping components are arranged vertically. The sand scraping components include a lead screw 31, a scraper 30, and a reducer 24 that is linked to the lead screw 31. An avoidance groove 29 corresponding to the scraper 30 is provided on the inner wall of the sand box 8. An installation groove 28 is provided on the inner wall of the sand box 8. The installation groove 28 is connected to the avoidance groove 29. The reducer 24 is set in the installation groove 28. The lead screw 31 is located in the installation groove 28 and is rotatably connected to the sand box 8. The scraper 30 is threadedly connected to the lead screw 31. The lead screws 31 in the two sets of sand scraping components are arranged perpendicular to each other. The sand box 8 is open at both ends. A thermoplastic membrane 5 is also connected to the end of the sand box 8 near the casting block 3. The opening of the sand box 8 away from the casting block 3 is covered with a sealing membrane 9.

[0038] Reference Figure 1 The sand box 8 is provided with a connection hole, and a second vacuum assembly is connected to the sand box 8. The second vacuum assembly includes a transmission pipe 23 and an air pump 7. The transmission pipe 23 is a flexible hose and is connected to the sand box 8 through the connection hole. The air pump 7 is connected to the sand box 8 through a support plate. The end of the transmission pipe 23 away from the sand box 8 is connected to the air pump 7. A sand-blocking cloth is connected in the connection hole. The sand-blocking cloth is a non-woven fabric.

[0039] Reference Figure 1Four screws 10 are connected to the sand box 8. The screws 10 are vertically arranged and pass through the work frame 1. The work frame 1 is equipped with two sprocket sets, each sprocket set including two gears 11 and a chain 12. The gears 11 are rotatably connected to the work frame 1. The inner sidewall of the gears 11 is provided with threads. The screws 10 pass through the gears 11 and are threadedly connected to the gears 11. The chain 12 is sleeved on the two gears 11. A worm gear 14 is rotatably connected to the work frame 1. The worm gear 14 is horizontally arranged. A motor 15 is connected to the work frame 1. The output shaft of the motor 15 is connected to the worm gear 14. A worm 13 is coaxially connected to one of the gears 11 in each sprocket set. The worm gear 13 meshes with the worm gear 14.

[0040] Reference Figure 2 and Figure 3 Dovetail grooves 16 are provided on the opposite side walls of the sand box 8. The cross-section of the dovetail grooves 16 is dovetail-shaped. There are two dovetail grooves 16 on the same side wall. One end of each dovetail groove 16 penetrates the side wall of the sand box 8 near the ground, and the distance between the other end and the side wall of the sand box 8 near the ground is different. A dovetail block 17 is detachably connected to the sand box 8. The dovetail block 17 is located in the dovetail groove 16 and slides in fit with the dovetail groove 16. A connecting strip 19 is connected to the end of the dovetail block 17 away from the bottom of the dovetail groove 16. A connecting groove 18 is provided on the box body 2, which is corresponding to the dovetail groove 16. The connecting groove 18 penetrates the side wall of the box body 2 away from the ground. The connecting strip 19 is inserted in the connecting groove 18 and slides in fit with the connecting groove 18.

[0041] Reference Figure 1 A cylinder 25 is connected to the side wall of the work frame 1 facing the ground. The piston rod of the cylinder 25 is set towards the box 2. A pressure plate 26 is connected to the piston rod of the cylinder 25. The pressure plate 26 slides in cooperation with the inner side wall of the sand box 8.

[0042] When making the sand mold, the dovetail block 17 is inserted into the longer dovetail groove 16. The motor 15 is started, and the motor 15 drives the worm gear 14 to rotate. The worm gear 14 drives the turbine 13 to rotate, and the turbine 13 drives the gear 11 connected to it to rotate. Under the transmission of the chain 12, the four gears 11 rotate simultaneously in the same direction. The screw 10 moves in the vertical direction, and the sand box 8 moves toward the box body 2. The connecting strip 19 is inserted into the connecting groove 18 until the connecting strip 19 abuts against the side wall of the connecting groove 18 near the ground. The dovetail block 17 and the dovetail groove 16 abut against the side wall away from the ground. At this time, the thermoplastic film 5 on the sand box 8 abuts against the casting block 3.

[0043] Sand is injected into the sand box 8 and heated by a heating wire. The sand falls onto the thermoplastic film 5, which deforms according to the shape of the casting block 3. Two reducers 24 are alternately activated, driving the lead screw 31 to rotate. The scraper 30 moves along the length of the lead screw 31, leveling the sand. The cylinder 25 is activated, pushing the pressure plate 26 toward the sand box 8. The pressure plate 26 flattens and compacts the sand in the sand box 8. Then, the cylinder 25 drives the pressure plate 26 away from the sand box 8, covering the sand box 8 with the sealing film 9. The air pump 7 in the second vacuum assembly is used to evacuate the sand box 8, completing the sand mold making.

[0044] Reference Figure 1 and Figure 2 When the dovetail block 17 is located in the shorter dovetail groove 16, and the dovetail block 17 and the dovetail groove 16 abut against the side wall away from the ground, and the connecting strip 19 abuts against the side wall of the connecting groove 18 near the ground, the sand mold and the casting block 3 are arranged at intervals in the vertical direction, and form the cavity of the exhaust manifold casting in the box body 2. The box body 2 is provided with an injection pipe 27, which is connected to the cavity.

[0045] The implementation principle of the exhaust manifold negative pressure die-casting device of this application is as follows:

[0046] The mold block 3 is installed at the bottom of the box 2 by sliding the slider 21 and the groove 20. The motor 15 is started, causing the sand box 8 to move toward the mold block 3 and fill it with gravel. The gravel is flattened and compacted by the scraper 30 and the pressure plate 26. Then the motor 15 is started again, causing the sand box 8 to move away from the mold block 3 and move the dovetail block 17 into the shorter dovetail groove 16. The motor 15 is then used to drive the sand box 8 toward the mold block 3 again, and the connecting strip 19 is inserted into the connecting groove 18 until the dovetail block 17 and the dovetail groove 16 are aligned with the side wall away from the ground. When the connecting strip 19 abuts against the side wall of the connecting groove 18 near the ground, the sand mold and the casting block 3 are spaced apart and form a cavity with the box body 2. The molten metal is injected into the cavity through the injection pipe 27. After the molten metal in the cavity cools down, the two air pumps 7 are turned off, the vacuum state in the casting block 3 and the sand box 8 is released, and the sand in the sand box 8 returns to the flowing state, so that the sand box 8 and the casting block 3 move away from each other, and the casting is completed. The exhaust manifold is cast by negative pressure casting. The exhaust manifold made in this way has a smooth surface and clear outline, which improves the casting quality of the exhaust manifold.

Claims

1. A negative pressure die-casting device for an exhaust manifold, characterized in that: The casting includes a work frame (1), a box (2), a sand mold, and a casting block (3). The box (2) is connected to the work frame (1). The sand mold and the casting block (3) are both located inside the box (2). The sand mold is slidably connected to the work frame (1) in the vertical direction. The casting block (3) is provided with air holes (4) and is covered with a thermoplastic film (5). The sand mold and the casting block (3) are arranged at intervals in the vertical direction and form the cavity of the exhaust manifold casting inside the box (2). The box (2) is provided with an injection pipe (27). The casting mold block (3) is connected to the cavity, and a first vacuum assembly is connected to the casting mold block (3). A second vacuum assembly is connected to the sand mold. The casting mold block (3) is hollow. The first vacuum assembly includes an air bag (6) and an air pump (7). The air pump (7) and the air bag (6) are both located inside the casting mold block (3). The air pump (7) is connected to the air bag (6). The sand mold includes a sand box (8) filled with sand. The second vacuum assembly includes a transmission pipe (23) and an air pump (7). The transmission pipe (23) is connected to the sand box (8) through a connecting hole. The opening of the sand box (8) away from the mold block (3) is covered with a sealing film (9). A sand scraping assembly is connected to the sand box (8). The sand box (8) is slidably connected to the work frame (1) in the vertical direction. Two dovetail grooves (16) are provided on the sand box (8). The cross-section of the dovetail grooves (16) is dovetail-shaped. One end of each of the two dovetail grooves (16) penetrates the side wall of the sand box (8) near the ground. The distance between the other end and the side wall of the sand box (8) near the ground is different. A dovetail block (17) is detachably connected to the sand box (8). The dovetail block (17) is located at the... The dovetail block (17) is located inside the dovetail groove (16) and slides in cooperation with the dovetail groove (16). A connecting strip (19) is connected to one end of the dovetail block (17) away from the bottom of the dovetail groove (16). A connecting groove (18) is provided on the box body (2) corresponding to the dovetail groove (16). The connecting groove (18) penetrates the side wall of the box body (2) away from the ground. The connecting strip (19) is inserted into the connecting groove (18) and slides in cooperation with the connecting groove (18). The sand box (8) is open at both ends. A thermoplastic film (5) is also connected to one end of the sand box (8) near the casting block (3).

2. The exhaust manifold negative pressure die-casting device according to claim 1, characterized in that: The sand scraping assembly includes a lead screw (31) and a scraper (30). The lead screw (31) is rotatably connected to the inner wall of the sand box (8), and the scraper (30) is threadedly connected to the lead screw (31). The side wall of the scraper (30) abuts against the side wall of the sand box (8).

3. The exhaust manifold negative pressure die-casting device according to claim 1, characterized in that: A pressure plate (26) is slidably connected to the work frame (1), and the pressure plate (26) is slidably engaged with the inner wall of the sand box (8).

4. The exhaust manifold negative pressure die-casting device according to claim 2, characterized in that: The inner wall of the sand box (8) is provided with a clearance groove (29) corresponding to the scraper (30), and the inner wall of the sand box (8) is provided with an installation groove (28), and the lead screw (31) is located in the installation groove (28).

5. The exhaust manifold negative pressure die-casting device according to claim 1, characterized in that: Heating wires are connected to both the mold block (3) and the sand box (8).

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