Composite forming device and method for electromagnetically driven rubber bag in cryogenic environment

Abstract

The invention provides a composite forming device and method for an electromagnetic driving rubber bag in a cryogenic environment. The device comprises a forming coil, a driving plate, a force transmission medium, the rubber bag, a female die and a plate material. The driving plate is located above the rubber bag, the forming coil is located above the driving plate, the rubber bag is located above the rubber cover tire, the rubber cover tire is located above the plate, the female die is located below the plate, and the radial lateral pushing coil is arranged at the end of the plate. According to the method, an aluminum alloy plate is put into liquid nitrogen to be subjected to subzero treatment, the temperature of the aluminum alloy plate is reduced to-192 DEG C to-185 DEG C, a pulse circuit is switched on, a driving plate generates pulse induction current, large electromagnetic force is generated, and the rubber bag forming plate is driven to be in a target shape. According to the method, the advantages that the copious cooling forming double-increasing effect can synchronously improve the material strength and toughness, the rubber bag forming precision is high, the electromagnetic forming speed is high, and the material forming limit is improved are integrated, and high-precision deformation of the difficult-to-deform aluminum alloy is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of metal material processing, and specifically relates to a composite forming device and method of an electromagnetically driven rubber bag in a cryogenic environment. Background Art

[0002] Electromagnetic forming is a method of high-speed processing of metal workpieces using pulsed magnetic field forces. Studies have shown that under high-speed impact, materials will produce different dynamic deformation behaviors compared to traditional quasi-static processing methods. During the high-speed deformation process, the sheet will undergo dynamic behaviors such as twinning, increased dislocation density, and adiabatic shearing, which effectively improves the forming limit of the material. In the relative technology, 5052 aluminum alloy was used to conduct electromagnetic assisted deep drawing forming experiments. The traditional deep drawing limit height of 5052 aluminum alloy is 19.8mm. Under electromagnetic assisted deep drawing, the limit height of 5052 aluminum alloy is 47.84mm, which is 141.6% higher than the limit height. In addition, the dislocation density of the material is significantly increased under electromagnetic assisted deep drawing. However, when electromagnetic forming is used to directly manufacture parts, the surface shape is difficult to control and the forming accuracy is poor.

[0003] Rubber bladder forming is a technology that uses the flow characteristics of high-pressure oil and rubber to achieve sheet deformation. It is widely used in the aviation field. The sheet metal after forming has high forming accuracy, smooth surface and high production efficiency. However, this technology restricts the flow of materials during the forming process, and the forming limit of the material is low. Summary of the invention

[0004] Purpose of the invention: In view of the above technical problems, the present application proposes a composite forming device and method for an electromagnetically driven rubber bag in a cryogenic environment.

[0005] In the first aspect, the present application provides a composite forming device for electromagnetically driven rubber bladders in a cryogenic environment, the device comprising a driving plate 5, a force transmission medium 6, a rubber bladder 7, a forming die and a plate 1, and a pulse current generating circuit 4 for forming a pulse induced current in the driving plate 5;

[0006] The forming die has a surface 12 for forming a plate material, the plate material has a rubber bag 7 , and the rubber bag 7 has a force transmission medium 6 . The pulse current generating circuit 4 can form a pulse current on the driving plate 5 .

[0007] Preferably, the plate 1 is first placed in a liquid nitrogen tank 2 for cryogenic treatment to reduce its temperature to -192°C to -185°C to obtain a cryogenic plate 3, and the cryogenic plate 3 is quickly transferred to a forming mold.

[0008] Preferably, the pulse current generating circuit 4 is provided with an electromagnetic forming coil 9 into which the pulse current can flow, and the electromagnetic forming coil 9 is close to the upper surface of the driving plate 5 .

[0009] Preferably, the forming mold includes a deep cavity die 8 , on which a vent hole 15 is provided, a rubber bag 7 acting on the sheet material is provided on the upper side of the deep cavity die 8 , and a driving plate 5 is provided on the upper side of the rubber bag 7 and the force transmission medium 6 .

[0010] Preferably, the electromagnetic forming coil is installed in a coil frame, and the electromagnetic forming coil includes a first electromagnetic forming coil and a second electromagnetic forming coil.

[0011] Preferably, the first electromagnetic forming coil 9 is placed on the first coil skeleton 10 and is located above the driving plate; the second electromagnetic forming coil 14 is placed on the second coil skeleton 13 and is located at the outer edge of the sheet material, which can laterally drive the edge of the deep cavity sheet material 12 to be formed to move inward, and the first electromagnetic forming coil 9 and the second electromagnetic forming coil 14 are connected in series.

[0012] Preferably, the forming mold comprises a flanging die 17 , the forming surface is the flanging die, a rubber bag 7 acting on the sheet material is arranged on the upper side of the flanging die, and a driving plate 5 is arranged on the upper side of the rubber bag 7 and the force transmission medium 6 .

[0013] Preferably, the forming mold includes a multi-rib structure die 19, the forming surface is a multi-rib structure die, a rubber bag 7 acting on the sheet material is arranged on the upper side of the multi-rib structure die, and a driving plate 5 is arranged on the upper side of the rubber bag 7 and the force transmission medium 6.

[0014] In a second aspect, the present application also provides a composite forming method of an electromagnetically driven rubber bag in a cryogenic environment, the method comprising the following steps:

[0015] S1: placing the formed sheet in a liquid nitrogen tank for cryogenic treatment, lowering the temperature of the sheet to -192°C to -185°C, and obtaining a cryogenic sheet;

[0016] S2: The cryogenic sheet is placed on the deep cavity die, and the first electromagnetic forming coil and the second electromagnetic forming coil are discharged. Under the action of axial stress, the rubber bag is driven to move downward, and under the joint action of radial stress, the deep cavity part is formed;

[0017] S3: placing the cryogenic sheet on the flanging die, discharging the first electromagnetic forming coil and the second electromagnetic forming coil, driving the rubber bag to move downward under the action of axial stress, and completing the flanging part forming under the joint action of radial stress;

[0018] S4: The cryogenic sheet is placed on the multi-rib structure die, and the first electromagnetic forming coil is discharged. Under the action of axial stress, the rubber bag is driven to move downward to complete the forming of the multi-rib structure part.

[0019] This application has the following technical effects:

[0020] The present invention combines the advantages of deep cold forming double-increasing effect to improve material strength and toughness simultaneously, rubber bag forming with high precision, and electromagnetic forming with high speed to improve material forming limit, so as to achieve high-precision deformation of difficult-to-deform aluminum alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of placing the sheet into a liquid nitrogen tank for cryogenic treatment;

[0022] Figure 2 It is a schematic diagram of a composite forming process of an electromagnetically driven rubber bag in a cryogenic environment and an initial state of bulging of the device;

[0023] Figure 3 It is a schematic diagram of a composite forming process of an electromagnetically driven rubber bag in a cryogenic environment and a bulging deformation state of the device;

[0024] Figure 4 A schematic diagram of a composite forming process of an electromagnetically driven rubber bag in a cryogenic environment and an initial state of the device flanging;

[0025] Figure 5 It is a schematic diagram of a composite forming process of an electromagnetically driven rubber bag in a cryogenic environment and the flanging deformation state of the device;

[0026] Figure 6 It is a schematic diagram of the composite forming process of an electromagnetically driven rubber bag in a cryogenic environment and the initial state of the multi-rib structure of the device;

[0027] Figure 7 It is a composite forming process of an electromagnetically driven rubber bag in a cryogenic environment and a schematic diagram of the deformation state of a multi-rib structure of the device;

[0028] Legend: 1 room temperature plate; 2 liquid nitrogen tank; 3 deep cold plate; 4 pulse current generating circuit; 5 driving plate; 6 force transmission medium; 7 rubber bag; 8 deep cavity die; 9 first electromagnetic forming coil; 10 first coil frame; 11 support body; 12 deep cavity plate to be formed; 13 second coil frame; 14 second electromagnetic forming coil; 15 exhaust hole; 16 flanging plate to be formed; 17 flanging die; 18 multi-rib plate to be formed; 19 multi-rib structure die. DETAILED DESCRIPTION

[0029] See also Figure 1-Figure 7The present invention discloses a composite forming process and device of an electromagnetically driven rubber bag under a cryogenic environment. It includes a forming coil, a driving plate, a force transmission medium, a rubber bag, a die and a sheet. The driving plate is located above the rubber bag, the forming coil is located above the driving plate, the rubber bag is located above the rubber outer tire, the rubber outer tire is located above the sheet, the die is located below the sheet, and a radial side thrust coil is provided at the end of the sheet. The present invention places the aluminum alloy sheet into liquid nitrogen for cryogenic treatment to reduce its temperature to -192°C to -185°C, connects to a pulse circuit, and the driving plate generates a pulse induced current, generates a large electromagnetic force, and drives the rubber bag to form the sheet to the target shape. The present invention combines the advantages of the double-increasing effect of deep cold forming to simultaneously improve the strength and toughness of the material, the high precision of rubber bag forming, and the high rate of electromagnetic forming to improve the forming limit of the material, to achieve high-precision deformation of difficult-to-deform aluminum alloys.

[0030] The present invention first discloses a composite forming process and device of an electromagnetically driven rubber bag in a cryogenic environment. The process includes a driving plate, a rubber bag, a force transmission medium, a forming die and a plate material, and a pulse current generating circuit for forming a pulse induced current in the driving plate. The forming die is provided with a surface for forming the plate material, and the plate material is provided with a rubber outer tire and a rubber bag, respectively. The pulse current generating circuit is configured to form a pulse current on the driving plate.

[0031] Furthermore, the composite forming process and device of the electromagnetically driven rubber bag in a cryogenic environment first puts the sheet into liquid nitrogen for cryogenic treatment for 10 to 20 minutes to reduce its temperature to -192°C to -185°C, and then quickly transfers it to the forming mold, with the transfer time being no more than 10 seconds.

[0032] Furthermore, the composite forming process and device of the electromagnetically driven rubber bag in a cryogenic environment are characterized in that an electromagnetic forming coil capable of passing a pulse current is provided on the pulse current generating circuit, and the electromagnetic forming coil is close to the upper surface of the driving plate.

[0033] Furthermore, the composite forming process and device of electromagnetically driven rubber bag under deep cold environment is characterized in that the forming mold includes a deep cavity die, the deep cavity die on the forming surface is provided with vent holes, the upper side of the deep cavity die is provided with a rubber outer tire and a rubber bag acting on the sheet material, the upper side of the rubber bag is provided with a driving plate, the electromagnetic forming coil is installed in the coil frame, and the coil frame of the first electromagnetic forming coil is located above the driving plate. The coil frame of the second electromagnetic forming coil is arranged at the outer edge of the sheet material, which can drive the edge of the sheet material to move inward laterally.

[0034] Furthermore, the composite forming process and device of electromagnetically driven rubber bladder under cryogenic environment is characterized in that the forming mold includes a flanging die, the forming surface is a flanging die, the upper side of the flanging die is provided with a rubber outer tire and a rubber bladder acting on the sheet material, the upper side of the rubber bladder is provided with a driving plate, the electromagnetic forming coil is installed in a coil frame, and the coil frame of the first electromagnetic forming coil is located above the driving plate. The coil frame of the second electromagnetic forming coil is arranged at the outer edge of the sheet material, and can laterally drive the edge of the sheet material to move inward.

[0035] Furthermore, the composite forming process and device of the electromagnetically driven rubber bag under a cryogenic environment are characterized in that the forming mold includes a multi-rib structure die, the forming surface is a multi-rib structure die, the upper side of the multi-rib structure die is provided with a rubber tire and a rubber bag acting on the sheet material, the upper side of the rubber bag is provided with a driving plate, the electromagnetic forming coil is installed in a coil frame, and the coil frame of the electromagnetic forming coil is located above the driving plate.

[0036] It should be noted that the strength and toughness of aluminum alloy sheets are improved simultaneously in a deep cold environment, which has a strong guiding significance for improving the forming limit of difficult-to-deform aluminum alloys. For the ultra-low temperature forming of 2219-O aluminum alloy, the study found that the elongation and hardening index of the material exceeded 45% and 0.4 respectively.

[0037] Aluminum alloy has high specific strength, but poor toughness at room temperature. The present invention combines electromagnetic forming and deep cold forming to improve the forming limit of aluminum alloy and the advantage of high forming precision of rubber bladder. The specific implementation method is as follows:

[0038] First, the sheet to be formed is placed in a liquid nitrogen tank for cryogenic treatment for 10 to 20 minutes to reduce its temperature to -192°C to -185°C to obtain a cryogenic sheet. Figure 1 As shown, the deep-cold sheet is transferred to the forming device for forming, and the transfer time is not more than 10s.

[0039] like Figure 2 and Figure 3 As shown, in this embodiment, the deep-cavity sheet to be formed after deep cooling is placed on the deep-cavity mold, the rubber bag is pressed down to contact the sheet, the pulse current generating circuit is turned on, and the driving plate and the edge of the deep-cavity sheet to be formed generate induced current and are acted upon by electromagnetic force. The driving plate drives the force transmission medium and the rubber bag to move under the action of the electromagnetic force, and the sheet is subjected to axial stress and radial stress at the same time, and finally fits the deep-cavity mold.

[0040] like Figure 4 and Figure 5As shown, in this embodiment, the deep-cooled flanging sheet to be formed is placed on the flanging mold, the rubber bag is pressed down to contact the sheet, the pulse current generating circuit is turned on, and the driving plate and the edge of the flanging sheet to be formed generate induced current and are affected by electromagnetic force. The driving plate drives the force transmission medium and the rubber bag to move under the action of the electromagnetic force, and the sheet is subjected to axial stress and radial stress at the same time, and finally fits the flanging mold.

[0041] like Figure 6 and Figure 7 As shown, in this embodiment, a cryogenic plate is placed on a multi-rib structure mold, a rubber bag is pressed down to contact the plate, a pulse current generating circuit is turned on, a driving plate generates an induced current, and is acted upon by an electromagnetic force. The driving plate drives the force transmission medium and the rubber bag to move under the action of the electromagnetic force, and the plate to be formed is subjected to axial stress and finally fits the multi-rib structure mold.

Claims

1. A composite forming device for electromagnetically driven rubber bags in a cryogenic environment, characterized in that: The device comprises a driving plate (5), a force transmission medium (6), a rubber bag (7), a forming die and a plate (1), and a pulse current generating circuit (4) for forming a pulse induction current in the driving plate (5); The forming die has a surface (12) for forming a plate material, the plate material has a rubber bag (7), the rubber bag (7) has a force transmission medium (6), and the pulse current generating circuit (4) can generate a pulse current on the driving plate (5).

2. The device according to claim 1, characterized in that First, the plate (1) is placed in a liquid nitrogen tank (2) for cryogenic treatment to reduce its temperature to -192°C to -185°C to obtain a cryogenic plate (3), and the cryogenic plate (3) is quickly transferred to a forming mold.

3. The device according to claim 1, characterized in that The pulse current generating circuit (4) is provided with an electromagnetic forming coil (9) capable of passing a pulse current, and the electromagnetic forming coil (9) is close to the upper surface of the driving plate (5).

4. The device according to claim 3, characterized in that The forming mold comprises a deep cavity die (8), the deep cavity die (8) is provided with an exhaust hole (15), a rubber bag (7) acting on the sheet material is provided on the upper side of the deep cavity die (8), and a driving plate (5) is provided on the upper side of the rubber bag (7) and the force transmission medium (6).

5. The device according to claim 4, characterized in that The electromagnetic forming coil is installed in a coil frame, and the electromagnetic forming coil includes a first electromagnetic forming coil and a second electromagnetic forming coil.

6. The device according to claim 5, characterized in that The first electromagnetic forming coil (9) is placed on the first coil frame (10) and is located above the driving plate; the second electromagnetic forming coil (14) is placed on the second coil frame (13) and is located at the outer edge of the sheet material, and can laterally drive the edge of the deep cavity sheet material (12) to be formed to move inward, and the first electromagnetic forming coil (9) and the second electromagnetic forming coil (14) are connected in series.

7. The device according to claim 5, characterized in that The forming die comprises a flanging die (17), the forming surface is the flanging die, a rubber bag (7) acting on the sheet material is arranged on the upper side of the flanging die, and a driving plate (5) is arranged on the upper side of the rubber bag (7) and the force transmission medium (6).

8. The device according to claim 7, characterized in that The forming mold comprises a multi-rib structure die (19), the forming surface is a multi-rib structure die, a rubber bag (7) acting on the sheet material is arranged on the upper side of the multi-rib structure die, and a driving plate (5) is arranged on the upper side of the rubber bag (7) and the force transmission medium (6).

9. A composite forming method of an electromagnetically driven rubber bag in a cryogenic environment, characterized in that: The method comprises the following steps: S1: placing the formed sheet in a liquid nitrogen tank for cryogenic treatment, lowering the temperature of the sheet to -192°C to -185°C, and obtaining a cryogenic sheet; S2: The cryogenic sheet is placed on the deep cavity die, and the first electromagnetic forming coil and the second electromagnetic forming coil are discharged. Under the action of axial stress, the rubber bag is driven to move downward, and under the joint action of radial stress, the deep cavity part is formed; S3: placing the cryogenic sheet on the flanging die, discharging the first electromagnetic forming coil and the second electromagnetic forming coil, driving the rubber bag to move downward under the action of axial stress, and completing the flanging part forming under the joint action of radial stress; S4: The cryogenic sheet is placed on the multi-rib structure die, and the first electromagnetic forming coil is discharged. Under the action of axial stress, the rubber bag is driven to move downward to complete the forming of the multi-rib structure part.

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