A low-pressure casting die for a compressor shell and a casting process method thereof

Abstract

This invention relates to the field of mold casting technology, specifically providing a low-pressure casting mold for a compressor housing and its casting process. The mold body comprises an upper mold body and a lower mold body joined together. The open ends of the upper and lower mold bodies can be joined to form a cavity for placing a sand core. A flow guide core is disposed within the cavity and fixed to the upper mold body. The lower end of the flow guide core is a conical flow guide section, and the outer side of the conical flow guide section is a flow guide ring section with multiple flow guide channels. A lower mold core is disposed below the flow guide core and fixed to the lower mold body. The lower mold core communicates with the pouring cup, which is fixed to the lower mold body via a pouring cup seat. The flow guide core guides the flow of molten aluminum entering the pouring cup during pouring, allowing the molten aluminum to flow uniformly through the sprue of the pouring cup, thus avoiding oxide scale and slag caused by aluminum splashing.

Description

Technical Field

[0001] This invention relates to the field of mold casting technology, specifically providing a low-pressure casting mold for a compressor housing and its casting process. Background Technology

[0002] As a crucial component of turbochargers, the compressor housing has found widespread application in the automotive, marine, and aerospace industries thanks to the continuous development of turbocharging technology. Currently, large-displacement diesel engines often employ compressor housings that are large in size and thin-walled (4-5mm) in thickness. Producing thin-walled, large-volume compressor housing parts using metal mold gravity casting is extremely challenging. Furthermore, gravity casting has the following drawbacks: 1. Low automation and low production efficiency: The pressure generated by gravity for feeding the castings results in a low yield, typically around 50%. 2. In the metal mold gravity casting process, molten aluminum fills the mold from top to bottom. This uneven filling process, with the downward impact easily forming oxide slag and scale, leads to unstable casting quality and a high scrap rate. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention provides a low-pressure casting mold for compressor housings, aiming to solve the problems of low efficiency and high scrap rate in the production of compressor housings using existing technologies.

[0004] To achieve the above objectives, the present invention provides a low-pressure casting mold for a compressor housing, comprising a mold body, wherein the mold body is formed by the joining of an upper mold body and a lower mold body, both of which have accommodating grooves inside. The open ends of the two accommodating grooves can be joined to form a cavity for placing a sand core. A flow guiding core is disposed in the cavity and is fixed to the upper mold body. The lower end of the flow guiding core is a conical flow guiding part, and the outer side of the conical flow guiding part is a flow guiding ring part. Multiple flow guiding channels are formed on the flow guiding ring part. A lower mold core is disposed below the flow guiding core and is fixed to the lower mold body. The lower mold core is connected to a pouring cup, which is fixed to the lower mold body by a pouring cup seat.

[0005] Preferably, the upper mold body has multiple ejection channels, and ejection rods are slidably arranged in the ejection channels. One end of the ejection rod is fixedly connected to the ejection plate, and the other end of the ejection rod can extend into the receiving cavity. The ejection plate is installed above the upper mold body through a reset mechanism.

[0006] Preferably, the reset mechanism includes a reset push rod fixed to the upper end of the upper mold body. The reset push rod passes through the ejector plate and is fixedly connected to the limiting ring. A reset spring is sleeved on the outside of the reset push rod, and the two ends of the reset spring abut against the ejector plate and the upper mold body, respectively.

[0007] Preferably, one end of the venting pin is connected to the cavity, and the other end of the venting pin passes through the upper mold body and extends to the outside of the upper mold body.

[0008] Preferably, an upper mold frame is fixed to the upper end of the upper mold body, and a lower mold frame is fixed to the lower end of the lower mold body.

[0009] Preferably, a cooling groove is provided on the lower end face of the lower mold body, and a cover plate is sealed at the opening of the cooling groove. The cover plate is fixedly connected to the lower mold body, and the cooling groove is connected to the air outlet pipe and the air inlet pipe.

[0010] Preferably, the upper mold body has an upper mold lifting ring fixed to its side wall.

[0011] Preferably, a lower mold lifting ring is fixed to the side wall of the lower mold body.

[0012] Preferably, a positioning pin is fixed to the lower end face of the upper mold body, and a positioning pin sleeve that cooperates with the positioning pin is embedded and fixed to the upper end face of the lower mold body.

[0013] The process method for casting compressor housing using the above-mentioned low-pressure casting mold for compressor housing of the present invention includes the following steps:

[0014] Step 1: Melt, purify, and refine the aluminum alloy solution;

[0015] Step 2: While refining the molten aluminum, preheat the mold cavity;

[0016] Step 3: After the refined molten metal is allowed to stand and degas, the aluminum alloy solution is transferred to the casting furnace of the low-pressure casting machine to await casting.

[0017] Step 4: Apply a uniform coating to the inside of the mold cavity before pouring;

[0018] Step 5: Place the sand core into the lower mold body, then close the mold and begin low-pressure casting. The molten aluminum fills the mold to cool the casting locally.

[0019] Step Six: After pouring is complete, remove the casting;

[0020] Step 7: Heat treat the formed compressor housing blank to give the compressor housing the required mechanical properties;

[0021] Step 8: The heat-treated blank is then cleaned of sand.

[0022] The purpose of this invention is to provide a low-pressure casting mold for compressor housings, which has the following beneficial effects:

[0023] ① The flow guide core is set to guide the aluminum liquid entering the pouring cup during pouring, so that the aluminum liquid can fill the cavity at a uniform speed from the sprue of the pouring cup, avoiding the oxide scale and oxide slag caused by aluminum liquid splashing.

[0024] ② The petal structure formed by the flow guide ring and the flow guide channel has a larger contact area with the casting compared to the planar structure. After the aluminum liquid solidifies, the tension can firmly fix the compressor housing casting in the upper mold body. Therefore, after the casting is completed, the petal structure can fix the compressor housing casting in the upper mold body. With the movement of the upper mold body, the casting is brought out from the second receiving groove. Attached Figure Description

[0025] Figure 1 This is the front view of the low-pressure casting mold for the compressor housing;

[0026] Figure 2 This is a schematic diagram of the low-pressure casting mold for the compressor housing;

[0027] Figure 3 This is a schematic diagram of the upper mold body;

[0028] Figure 4 This is a schematic diagram of the flow guide core structure;

[0029] Figure 5 This is a partial isometric view of the lower mold body from a first-person perspective;

[0030] Figure 6 This is a schematic diagram of the lower mold body;

[0031] Figure 7 This is a left view of the low-pressure casting mold for the compressor housing.

[0032] In the diagram: 10-Upper mold body; 20-Lower mold body; 30-Receiving cavity; 301-First receiving groove; 302-Second receiving groove; 31-Guiding core; 310-Conical guiding part; 311-Guiding ring part; 312-Guiding channel; 32-Lower mold core; 33-Sprue cup; 34-Sprue cup seat; 40-Ejection channel; 41-Ejection rod; 42-Ejection plate; 50-Reset ejector rod; 51-Limiting ring; 53-Reset spring; 55-Exhaust pin; 60-Upper mold frame; 61-Lower mold frame; 64-Cooling tank; 65-Cover plate; 66-Exhaust pipe; 67-Inlet pipe; 70-Upper mold lifting ring; 71-Lower mold lifting ring; 80-Positioning pin; 81-Positioning pin sleeve. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] like Figure 1-7 As shown, a low-pressure casting mold for a compressor housing includes a mold body, which is formed by the mating of an upper mold body 10 and a lower mold body 20. The upper mold body 10 has an upper mold frame 60 bolted to its upper end, and the lower mold body 20 has a lower mold frame 61 bolted to its lower end. Both the upper mold frame 60 and the lower mold frame 61 serve as a connecting and fixing mechanism, and the mold body is fixed to a low-pressure casting machine via the upper mold frame 60 and the lower mold frame 61. The upper mold body 10 has a first receiving groove 301 at its bottom, and the lower mold body 20 has a second receiving groove 302 at its top. The open ends of the two receiving grooves can be joined together to form a receiving cavity 30. The shape of the receiving cavity 30 is designed according to the compressor housing to be cast, and the receiving cavity 30 contains a sand core and molten aluminum. The cavity 30 contains a flow guide core 31. The upper end of the flow guide core 31 extends into the upper mold body 10 and is fixed thereto. The lower end of the flow guide core 31 is a conical flow guide portion 310. The outer side of the conical flow guide portion 310 is a flow guide ring portion 311, which is located outside the conical flow guide portion 310 and is coaxially arranged with it. Multiple flow guide channels 312 are formed on the flow guide ring portion 311, dividing it into petal shapes. A lower mold core 32 is fixed on the lower mold body 20. A sprue cup 33 is positioned below the lower mold core 32. An annular channel is formed in the middle of the lower mold core 32, which communicates with the sprue cup 33. The sprue cup 33 is fixed to the lower mold body 20 via a sprue cup seat 34. The guide core 31 guides the molten aluminum entering the pouring cup 33 during pouring, allowing the molten aluminum to flow evenly through the sprue of the pouring cup 33 and fill the mold cavity, avoiding oxide scale and slag caused by splashing molten aluminum. In addition, the petal structure formed by the guide ring 311 and the guide channel 312 has a larger contact area with the casting compared to a planar structure. After the molten aluminum solidifies, the tension can firmly fix the compressor housing casting in the upper mold body 10. Therefore, after pouring, the petal structure can fix the compressor housing casting in the upper mold body 10, and with the movement of the upper mold body 10, the casting is carried out from the second receiving groove 302.

[0035] As a further explanation of this embodiment, multiple ejection channels 40 are provided inside the upper mold body 10. The ejection channels 40 penetrate the upper mold body 10. An ejection rod 41 is slidably arranged inside the ejection channel 40. One end of the ejection rod 41 extends out of the upper mold body 10 and is fixedly connected to the ejection plate 42. The other end of the ejection rod 41 can extend out of the lower part of the upper mold body 10 and into the receiving cavity 30. One end of a reset push rod 50 is fixed at the upper end of the upper mold body 10. The other end of the reset push rod 50 penetrates the ejection plate 42 and is fixedly connected to the limiting ring 51. A reset spring 53 is sleeved on the outside of the reset push rod 50. The upper end of the reset spring 53 abuts against the ejection plate 42, and the lower end of the reset spring 53 abuts against the upper mold body 10. The reset spring 53 is normally in a compressed state. The ejection plate 42 abuts against the limiting ring 51 under the elastic force of the reset spring 53.

[0036] As a further explanation of this embodiment, one end of the venting pin 55 is connected to the cavity 30, and the other end of the venting pin 55 passes through the upper mold body 10 and extends to the outside of the upper mold body 10. The venting pin 55 plays a good role in venting during the aluminum liquid filling process, which facilitates the forming of the compressor housing casting.

[0037] As a further explanation of this embodiment, a cooling groove 64 is provided on the lower end face of the lower mold body 20. Preferably, there are four cooling grooves 64 arranged in pairs, with the two cooling grooves in the same pair interconnected. A cover plate 65 is sealed to the opening of each cooling groove 64, and the cover plate 65 is fixedly connected to the lower mold body 20. The cooling groove 64 is connected to an exhaust pipe 66 and an intake pipe 67. External air enters the cooling groove 64 through the intake pipe 67 to cool the molten aluminum in the receiving cavity 30 near the cooling groove 64, thereby achieving the purpose of cooling areas where a large amount of molten aluminum has accumulated. After cooling, the air is discharged through the exhaust pipe 66.

[0038] As a further explanation of this embodiment, the upper mold body 10 is fixed with an upper mold lifting ring 70 on its side wall, and the lower mold body 20 is fixed with a lower mold lifting ring 71 on its side wall. The upper mold lifting ring 70 and the lower mold lifting ring 71 are provided to facilitate the handling and movement of the upper mold body 10 and the lower mold body 20.

[0039] As a further explanation of this embodiment, two positioning pins 80 are fixed on the lower end face of the upper mold body 10. The two positioning pins 80 are diagonally arranged at the lower end of the upper mold body 10. A groove is formed at the same vertical position as the positioning pins 80 on the upper end of the lower mold body 20. A positioning pin sleeve 81 is embedded and fixed in the groove. The positioning pins 80 can be moved within the positioning pin sleeve 81. The two cooperate with each other and play a positioning and guiding role when the upper mold body 10 and the lower mold body 20 are closed.

[0040] In use, the mold is placed in the corresponding position on the low-pressure casting machine, and the machine is started. The low-pressure casting machine drives the upper mold body 10 to move upward to its maximum stroke position via the upper mold frame 60. A sand core is placed in the lower mold body 20 and positioned by the lower mold core 32. After placement, the upper mold body 10 moves downward until it aligns with the lower mold body 20. Then, molten aluminum is poured in through the channel of the pouring cup 33. The molten aluminum is guided by the conical guide part 310 of the guide core 31 and the guide channel 312, and fills the receiving cavity 30 at a uniform speed. As the molten aluminum enters, the air in the receiving cavity 30 is quickly discharged under the action of the exhaust pin 55. After the molten aluminum is stamped, cooling air is introduced into the cooling tank 64 through the air inlet pipe 67 to cool the molten aluminum. The cooled air is then discharged through the air outlet pipe 66. After cooling is complete, the low-pressure casting machine is started, which drives the upper mold body 10 to move upward. The low-pressure casting machine is equipped with a limiting protrusion, which can hold the ejector plate 42 from above. The ejector plate 42 cannot move upward with the upper mold body 10. The ejector rod 41 fixed on the ejector plate 42 will extend out of the bottom of the upper mold body 10 and abut against the air-cushion casting until the air-cushion casting is ejected. At this time, the return spring 53 is further compressed. After the casting is ejected, the low-pressure casting machine drives the upper mold body 10 to move downward. The return spring 53 returns to its original position and pushes the ejector plate 42 and the upper mold body 10 to the initial distance. At this time, the lower end of the ejector rod 41 returns to the ejection channel inside the upper mold body 10. After the upper mold body 10 falls down and closes with the lower mold body 20, the next production can be carried out.

[0041] The process method for casting compressor housing using the above-mentioned low-pressure casting mold for compressor housing of the present invention includes the following steps:

[0042] Step 1: Melt and purify the aluminum alloy solution, and then add refining agents for further refining.

[0043] Step 2: While refining the molten aluminum, preheat the mold cavity 30 to 300°C, and wait for pouring.

[0044] Step 3: After the refined molten metal is allowed to stand and degas, the aluminum alloy solution is transferred to the casting furnace of the low-pressure casting machine using a transfer bag to await casting.

[0045] Step 4: Before pouring, spray the mold cavity with a uniform coating. Repeat the coating process after producing an average of 8-10 products.

[0046] Step 5: Place the sand core at position 20 of the lower mold body, then close the mold and begin low-pressure casting. After the aluminum liquid fills the mold, turn on the air cooling to cool the casting locally.

[0047] Step Six: After the pouring is completed, the upper mold body 10 moves upward and the casting is removed.

[0048] Step 7: Place the formed compressor housing blank in an aluminum alloy heat treatment equipment for heat treatment to give the compressor housing the required mechanical properties.

[0049] Step 8: Sand removal treatment. Grind, clean, and shot blast the heat-treated blank to obtain a qualified product.

[0050] This invention is not limited to the specific embodiments described above. Any modifications made by those skilled in the art based on the above concept without creative effort are within the scope of protection of this invention.

Claims

1. A low pressure casting mold for a compressor case, characterized by, Includes a mold body, which is formed by the mating of an upper mold body (10) and a lower mold body (20). Both the upper mold body (10) and the lower mold body (20) are provided with receiving grooves. The open ends of the two receiving grooves can be joined together to form a receiving cavity (30) for placing the sand core. A flow guiding core (31) is arranged in the receiving cavity (30). The flow guiding core (31) is fixed to the upper mold body (10). The lower end of the flow guiding core (31) is a conical flow guiding part (310). 10) The outer side is a flow guide ring (311), on which multiple flow guide channels (312) are opened. The multiple flow guide channels (312) divide the flow guide ring (311) into a petal shape. A lower mold core (32) is provided below the flow guide core (31). The lower mold core (32) is fixed on the lower mold body (20). The lower mold core (32) is connected to the pouring cup (33). The pouring cup (33) is fixed on the lower mold body (20) through the pouring cup seat (34). Multiple ejection channels (40) are provided inside the upper mold body (10). An ejection rod (41) is slidably arranged in the ejection channel (40). One end of the ejection rod (41) is fixedly connected to an ejection plate (42), and the other end of the ejection rod (41) can extend into the receiving cavity (30). The ejection plate (42) is installed above the upper mold body (10) through a reset mechanism. The reset mechanism includes a reset push rod (50) fixed to the upper end of the upper mold body (10). The reset push rod (50) passes through the ejection channel. The material plate (42) is fixedly connected to the limiting ring (51). The reset push rod (50) is sleeved with a reset spring (53). The two ends of the reset spring (53) abut against the ejector plate (42) and the upper mold body (10) respectively. The petal structure formed by the flow guide ring (311) and the flow guide channel (312) can increase the contact area with the casting and fix the casting to the upper mold body (10) by surface tension after the aluminum liquid solidifies, so that the casting is brought out of the lower mold body (20) along with the upper mold body (10) when the mold is opened.

2. The low-pressure casting mold for compressor housing according to claim 1, characterized in that, The cavity (30) is connected to one end of an exhaust pin (55), and the other end of the exhaust pin (55) passes through the upper mold body (10) and extends to the outside of the upper mold body (10).

3. The low-pressure casting mold for compressor housing according to claim 1, characterized in that, The upper mold body (10) is fixed with an upper mold frame (60) at its upper end, and the lower mold body (20) is fixed with a lower mold frame (61) at its lower end.

4. The low-pressure casting mold for compressor housing according to claim 1, characterized in that, The lower mold body (20) has a cooling groove (64) on its lower end face. The opening of the cooling groove (64) is sealed with a cover plate (65). The cover plate (65) is fixedly connected to the lower mold body (20). The cooling groove (64) is connected to the air outlet pipe (66) and the air inlet pipe (67).

5. The low-pressure casting mold for compressor housing according to claim 1, characterized in that, The upper mold body (10) has an upper mold lifting ring (70) fixed to its side wall.

6. The low-pressure casting mold for compressor housing according to claim 1, characterized in that, The lower mold body (20) has a lower mold lifting ring (71) fixed to its side wall.

7. The low-pressure casting mold for compressor housing according to claim 1, characterized in that, The lower end face of the upper mold body (10) is fixed with a positioning pin (80), and the upper end face of the lower mold body (20) is embedded with a positioning pin sleeve (81) that cooperates with the positioning pin (80).

8. A casting process method using the low-pressure casting mold for a compressor housing as described in claim 1, characterized in that, Includes the following steps: Step 1: Melt, purify, and refine the aluminum alloy solution; Step 2: While refining the molten aluminum, preheat the mold cavity (30); Step 3: After the refined molten metal is allowed to stand and degas, the aluminum alloy solution is transferred to the casting furnace of the low-pressure casting machine to await casting. Step 4: Before pouring, uniformly spray paint into the mold cavity (30); Step 5: Place the sand core into the lower mold body (20), then close the mold and begin low-pressure casting. The aluminum liquid fills the mold to cool the casting locally. Step Six: After pouring, remove the casting; Step 7: Heat treat the formed compressor housing blank to give the compressor housing the required mechanical properties; Step 8: The heat-treated blank is then cleaned of sand.

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