Casting mold and casting process for gearbox shell of air compressor

Abstract

The invention relates to the field of casting, and discloses a casting mold and a casting process for an air compressor gearbox shell, and the casting mold comprises a fixed mold, a movable mold, an electromagnetic vacuum valve communicating with a mold cavity, and a local extrusion mechanism arranged on the movable mold; the local extrusion mechanism comprises an air cylinder and a movable block, and an ejection mechanism is installed on the fixed die. The casting process comprises the following steps: before casting, exhausting air from the cavity through the electromagnetic vacuum valve; injecting molten metal; when the molten metal is in a pasty solidification period, the air cylinder pushes the movable block to carry out forced feeding; during forced feeding, the electromagnetic vacuum valve is quickly opened and closed, so that residual gas is discharged; and after the workpiece is solidified, the movable block is pushed again through the air cylinder at the moment of opening the mold, and the workpiece is stripped from the movable mold and stays on the fixed mold. The problems of casting air holes, shrinkage porosity defects and workpiece adhesion to the movable mold are solved, and the casting compactness and the workpiece strength are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of casting, in particular to a casting mold and casting process for an air compressor gear box shell. BACKGROUND

[0002] The air compressor gear box shell is a key component of the transmission system, and its internal structure is relatively complex, and often accompanied by the characteristics of wall thickness difference, such as the existence of thin-walled area and thick mounting boss at the same time. When producing such a shell by using traditional high-pressure die casting process, in order to ensure that the metal liquid can completely fill the complex cavity, the injection system must provide very high filling speed, but this will cause the gas in the cavity to be entrained into the metal liquid, and form dispersed porosity after the workpiece cools, affecting the air tightness and mechanical strength of the casting.

[0003] At the same time, due to the existence of thick parts in the workpiece, the cooling speed of these areas during solidification process is much slower than that of the thin-walled area. When the workpiece changes from liquid to solid, the thick part cannot be supplied with metal liquid in time, and its solidification shrinkage cannot be fully compensated, resulting in shrinkage, shrinkage hole and other defects in the workpiece.

[0004] In addition, in the mold opening link of die casting production, limited by the structure of the workpiece or the layout of the cavity, the casting is attached to the movable mold side after the mold is opened. However, the conventional ejection demolding mechanism is installed on the fixed mold, and the attachment of the workpiece to the movable mold causes the subsequent ejection process to fail to proceed smoothly, which requires manual intervention, affecting the automation and continuity of production. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application provides a casting mold and casting process for an air compressor gear box shell, which solves the problems of internal defects such as porosity and shrinkage in the complex shell during die casting, and demolding difficulty caused by the adhesion of the workpiece to the movable mold.

[0006] To achieve the above purpose, the present application realizes the following technical scheme: a casting mold for an air compressor gear box shell, comprising a fixed mold, a ejection mechanism is installed inside the fixed mold, four positioning rods are slidingly connected inside the fixed mold, a movable mold is fixedly connected between the four positioning rods outside, an injection port is fixedly connected inside the movable mold, an inner mold chamber is fixedly connected inside the movable mold and the fixed mold, two inner mold chambers are combined to form a cavity, a heat dissipation channel is arranged inside the inner mold chamber, and a local extrusion mechanism is installed inside the movable mold. The local extrusion mechanism comprises a gas cylinder, the gas cylinder is fixedly connected outside the movable mold, a top rod is fixedly connected to the output end of the gas cylinder, an activity block is fixedly connected to the end of the top rod away from the gas cylinder, and two limit rods are fixedly connected to the side of the activity block close to the top rod.

[0007] Preferably, an electromagnetic vacuum valve is fixedly connected to the top of the moving mold, and the electromagnetic vacuum valve is connected to the vacuum pump through a hose.

[0008] Preferably, the push rod is externally slidably connected to the interior of the moving mold and the interior of the inner mold chamber mounted on the moving mold.

[0009] Preferably, the movable block is externally slidably connected to the interior of the inner mold chamber, and the limiting rod is externally slidably connected to the interior of the inner mold chamber.

[0010] Preferably, the electromagnetic vacuum valve is connected to the cavity between the two inner mold chambers, and the injection port is connected to the cavity.

[0011] Preferably, a casting process for an air compressor gearbox housing includes the following steps: S1. Before die casting begins, the cavity is evacuated using an electromagnetic vacuum valve to create negative pressure in the cavity. S2. Inject molten metal into the cavity; S3. When the molten metal is in the paste-like solidification stage, the cylinder pushes the push rod, which drives the movable block to move under the limit of the limit rod, thereby forcibly compressing the molten metal in the cavity. S4. While performing the forced compression described in step S3, perform at least one rapid switching action on the electromagnetic vacuum valve to discharge residual gas; After the workpiece solidifies, S5 performs the mold opening operation. At the moment of mold opening, the cylinder pushes the movable block again to peel the workpiece from the inner mold chamber on the moving mold, so that the workpiece stays in the inner mold chamber on the fixed mold.

[0012] Preferably, step S2, which involves injecting molten metal into the cavity, specifically includes: By pushing the injection punch inside the casting machine at a slower speed, the molten metal can be smoothly filled into the injection port. Then switch to a faster speed to push the injection punch, so that the molten metal fills the cavity at high speed; When the cavity is completely filled, the injection punch continues to push, applying high pressure to compact the molten metal.

[0013] Preferably, in step S5, after the workpiece rests on the inner mold chamber within the fixed mold, the workpiece is ejected and demolded by the ejection mechanism.

[0014] This invention provides a casting mold and casting process for an air compressor gearbox housing. It offers the following advantages: 1. This invention uses an electromagnetic vacuum valve to evacuate the mold cavity before injecting molten metal and employs a three-stage injection process during filling to reduce gas entrapment during high-speed filling. Simultaneously, during the workpiece's pasty solidification period, a cylinder pushes a movable block to forcefully compensate for thicker areas. This effectively solves the problems of cavitation caused by air entrapment and shrinkage caused by solidification contraction within the workpiece, significantly improving the workpiece's density and strength.

[0015] 2. This invention, while the cylinder pushes the movable block for forced feeding, utilizes extrusion pressure to expel residual trace amounts of gas, and coordinates with the rapid opening and closing of the electromagnetic vacuum valve to discharge the extruded gas. This achieves secondary removal of the gas extruded during the solidification stage, further reducing the internal porosity of the workpiece.

[0016] 3. This invention utilizes a newly added cylinder and movable block to perform an auxiliary pushing action at the moment of mold opening, causing the workpiece to peel off from the moving mold and ensuring that the workpiece remains on the fixed mold equipped with an ejection mechanism. This solves the problem of difficult demolding caused by the workpiece adhering to the moving mold during mold opening, ensuring the normal progress of subsequent demolding processes and reducing operational difficulty. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of the present invention; Figure 2 This is an exploded view of the moving model of the present invention; Figure 3 This is a cross-sectional view of the moving mold of the present invention; Figure 4 This is a schematic diagram of the partial extrusion mechanism of the present invention; Figure 5 This is a schematic diagram of the process flow of the present invention.

[0018] The components include: 1. Fixed mold; 2. Ejection mechanism; 3. Positioning rod; 4. Moving mold; 5. Injection port; 6. Inner mold chamber; 7. Heat dissipation channel; 8. Cylinder; 9. Ejector rod; 10. Movable block; 11. Limiting rod; 12. Electromagnetic vacuum valve. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] To better understand the present invention, the above content will be described in detail below with reference to specific embodiments.

[0021] Please see the appendix Figure 1 - AppendixFigure 5 This invention provides a casting mold and casting process for an air compressor gearbox housing.

[0022] The first aspect of this invention provides a casting mold for an air compressor gearbox housing, comprising: a fixed mold 1; an ejector mechanism 2 installed inside the fixed mold 1; four positioning rods slidably connected inside the fixed mold 1; a movable mold 4 fixedly connected externally to the four positioning rods 3; an injection port 5 fixedly connected inside the movable mold 4; inner mold chambers 6 fixedly connected inside both the movable mold 4 and the fixed mold 1; two inner mold chambers 6 merging to form a cavity; heat dissipation channels 7 provided inside the inner mold chambers 6; a partial extrusion mechanism installed inside the movable mold 4; and the fixed mold 1 being directly fixed to a casting machine, and connected to the movable mold 4. When used in conjunction, the ejector mechanism 2 works with the drive device inside the casting machine to eject the workpiece. The positioning rod 3 limits the movement of the moving mold 4 to ensure that the moving mold 4 and the fixed mold 1 can be precisely aligned and fitted. The moving mold 4 is installed on the side of the casting machine that can move back and forth. The injection port 5 is used to inject molten metal into the inner mold chamber 6. The inner mold chamber 6 is used to cooperate with each other to form a cavity between them. The shape of the cavity is the shape of the product to be produced. The heat dissipation channel 7 is used to cool the inner mold chamber 6, thereby cooling the workpiece in the cavity. The partial extrusion mechanism includes a cylinder 8, which is externally fixed to the outside of the moving mold 4. A push rod 9 is fixedly connected to the output end of the cylinder 8. A movable block 10 is fixedly connected to the end of the push rod 9 away from the cylinder 8. Two limit rods 11 are fixedly connected to the side of the movable block 10 near the push rod 9. The cylinder 8 is used to push the push rod 9 to move, and the push rod 9 is used to transmit the thrust of the cylinder 8 to the movable block 10. The movable block 10 is used to move within the inner mold chamber 6 to force the molten metal to shrink and prevent shrinkage. The limit rods 11 are used to restrict the movement direction of the movable block 10 to ensure that the movable block 10 can only move in the specified direction and will not deviate.

[0023] An electromagnetic vacuum valve 12 is fixedly connected to the top of the moving mold 4. The electromagnetic vacuum valve 12 is connected to the vacuum pump through a hose. The electromagnetic vacuum valve 12 is used to draw air into the cavity, thereby creating a negative pressure in the cavity.

[0024] The ejector rod 9 is externally slidably connected inside the moving mold 4 and inside the inner mold chamber 6 mounted on the moving mold 4, restricting the movement direction of the ejector rod 9.

[0025] The movable block 10 is externally slidably connected to the inside of the inner mold chamber 6, restricting the movement direction of the movable block 10. The limiting rod 11 is externally slidably connected to the inside of the inner mold chamber 6, restricting the movement direction of the limiting rod 11.

[0026] The electromagnetic vacuum valve 12 is connected to the cavity between the two inner mold chambers 6, and the injection port 5 is connected to the cavity, so that the molten metal can enter the cavity and the gas in the cavity can be smoothly discharged from the electromagnetic vacuum valve 12.

[0027] A second aspect of the present invention provides a casting process for an air compressor gearbox housing, comprising the following steps: S1. Before casting begins, after the fixed mold 1 and the moving mold 4 are closed and before the molten metal is injected, the control system opens the electromagnetic vacuum valve 12. The vacuum pump connected to the electromagnetic vacuum valve 12 starts to evacuate the cavity formed by the merging of the two inner mold chambers 6, creating a negative pressure inside the cavity. This removes air from the cavity before the molten metal is injected, reducing gas entrapment during subsequent molten metal filling.

[0028] S2. Subsequently, molten metal is injected into the cavity.

[0029] Step S2, injecting molten metal, specifically involves a three-stage injection process performed by the injection punch inside the casting machine. In the first stage, the injection punch is pushed at a slower speed to allow the molten metal to smoothly fill the injection port 5. In the second stage, the speed is switched to a faster speed to allow the molten metal to fill the cavity at high speed. In the third stage, when the cavity is completely filled, the injection punch continues to push, applying high pressure to the molten metal within the cavity to compact it, thereby reducing the air content in the molten metal, increasing its density, and reducing the possibility of cavitation in the workpiece.

[0030] S3. When the molten metal is in the paste-like solidification stage, shrinkage will occur in the workpiece due to solidification shrinkage. At this time, cylinder 8 is activated, pushing push rod 9 forward. Under the guidance and limitation of limit rod 11, push rod 9 drives movable block 10 to move into the cavity, squeezing the molten metal in the paste-like solidification stage in the cavity to achieve forced shrinkage, thereby eliminating the shrinkage phenomenon caused by solidification shrinkage in the thicker parts of the workpiece.

[0031] S4. While performing the forced feeding step S3, the residual trace gas inside the workpiece extruded by the extrusion action is collected. At this time, the control system sends a command to the electromagnetic vacuum valve 12, causing the electromagnetic vacuum valve 12 to perform at least one rapid opening and closing action. Utilizing the instantaneous suction force of the vacuum system, this portion of the extruded residual gas is discharged from the mold cavity.

[0032] Next, the workpiece is cooled through the heat dissipation channel 7. After the workpiece has completely solidified and cooled down, the moving mold 4 retracts and the mold opening operation is performed.

[0033] S5. At the moment of mold opening, cylinder 8 restarts, pushing movable block 10 to generate an instantaneous thrust. This thrust solves the problem of difficult demolding caused by the workpiece being attached to the moving mold, peeling the workpiece from the inner mold chamber 6 on the moving mold 4 side, ensuring that the workpiece remains in the inner mold chamber 6 on the fixed mold 1 side.

[0034] After the workpiece is positioned on the fixed mold 1 as expected, the ejection mechanism 2 installed inside the fixed mold 1 is activated to eject the workpiece from the inner mold chamber 6, thus completing the demolding and casting process, allowing the casting of the next workpiece to continue.

Claims

1. A casting mold for an air compressor gearbox housing, characterized in that, The mold includes a fixed mold (1), an ejector mechanism (2) installed inside the fixed mold (1), four positioning rods (3) slidably connected inside the fixed mold (1), a moving mold (4) fixedly connected between the four positioning rods (3), an injection port (5) fixedly connected inside the moving mold (4), an inner mold chamber (6) fixedly connected inside both the moving mold (4) and the fixed mold (1), the two inner mold chambers (6) are merged to form a cavity, a heat dissipation channel (7) is provided inside the inner mold chamber (6), and a local extrusion mechanism is installed inside the moving mold (4). The local extrusion mechanism includes a cylinder (8), which is fixedly connected to the outside of the moving mold (4). A push rod (9) is fixedly connected to the output end of the cylinder (8). A movable block (10) is fixedly connected to the end of the push rod (9) away from the cylinder (8). Two limit rods (11) are fixedly connected to the side of the movable block (10) near the push rod (9).

2. The casting mold for an air compressor gearbox housing according to claim 1, characterized in that, An electromagnetic vacuum valve (12) is fixedly connected to the top of the moving mold (4), and the electromagnetic vacuum valve (12) is connected to the vacuum pump through a hose.

3. The casting mold for an air compressor gearbox housing according to claim 1, characterized in that, The top rod (9) is externally slidably connected inside the moving mold (4) and inside the inner mold chamber (6) installed on the moving mold (4).

4. The casting mold for an air compressor gearbox housing according to claim 1, characterized in that, The movable block (10) is externally slidably connected to the inside of the inner mold chamber (6), and the limiting rod (11) is externally slidably connected to the inside of the inner mold chamber (6).

5. The casting mold for an air compressor gearbox housing according to claim 2, characterized in that, The electromagnetic vacuum valve (12) is connected to the cavity between the two inner mold chambers (6), and the injection port (5) is connected to the cavity.

6. A casting process for an air compressor gearbox housing, characterized in that, Includes the following steps: S1. Before die casting begins, the cavity is evacuated by an electromagnetic vacuum valve (12) to create a negative pressure in the cavity. S2. Inject molten metal into the cavity; S3. When the molten metal is in the paste solidification period, the cylinder (8) pushes the top rod (9), which drives the movable block (10) to move under the limit of the limiting rod (11), and forces the molten metal in the cavity to be replenished. S4. While performing the forced feeding described in step S3, perform at least one rapid switching action on the electromagnetic vacuum valve (12) to discharge the residual gas; After the workpiece solidifies, S5 performs the mold opening operation. At the moment of mold opening, the cylinder (8) pushes the movable block (10) again to peel the workpiece from the inner mold chamber (6) on the moving mold (4) and make the workpiece stay in the inner mold chamber (6) on the fixed mold (1).

7. The casting process for an air compressor gearbox housing according to claim 6, characterized in that, Step S2, which involves injecting molten metal into the cavity, specifically includes: By pushing the injection punch inside the casting machine at a slower speed, the molten metal is smoothly filled into the injection port (5). Then switch to a faster speed to push the injection punch, so that the molten metal fills the cavity at high speed; When the cavity is completely filled, the injection punch continues to push, applying high pressure to compact the molten metal.

8. The casting process for an air compressor gearbox housing according to claim 6, characterized in that, In step S5, after the workpiece rests on the inner mold chamber (6) inside the fixed mold (1), the workpiece is ejected and demolded by the ejection mechanism (2).

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