3-meter-level aerospace carrier rocket tank bottom local heating forming device and method

Abstract

This invention provides a 3-meter-class aerospace launch vehicle propellant tank bottom local heating and forming device, including a positioning unit, a heating unit, a forming mold unit, and a servo control system. The positioning unit automatically aligns the part with a reference line and rotates and flips the part according to set values, thereby bringing the area to be heated and formed to the lowest position of the part, and records the movement sequence. The heating unit converts electrical energy into heat energy and transfers the heat energy to the area to be heated on the part through efficient conduction, with a temperature detection device serving as the control signal for the electrical energy to heat energy conversion. The forming mold unit receives the temperature signal measured by the heating unit and begins to move, controlling the displacement to the set value to complete the forming process, and then sends a control signal to the positioning unit to bring the part to zero. This invention effectively improves the forming limit of the material, optimizes the forming process of the tank bottom parts, significantly shortens the tank bottom manufacturing cycle, and improves the product quality consistency of the tank bottom parts.

Description

Technical Field

[0001] This invention relates to the field of local precision heating and forming of large metal curved surface components in the aerospace industry, and particularly to a device and method for local heating and forming of the bottom of a 3-meter-class space launch vehicle tank. Background Technology

[0002] Integral manufacturing technology for aerospace components is crucial for ensuring lightweight design and manufacturing, high reliability in service, and low-cost application. For the bottom components of rocket propellant tanks, with diameters exceeding 3 meters and complex shapes, they are typical large, thin-walled curved components, presenting significant challenges in forming and manufacturing, long production processes, and high manufacturing costs. Traditional manufacturing methods employ welded structures, but weld reinforcement and deformation negatively impact the efficiency of the tank bottom structure. To achieve high reliability, low cost, and high efficiency, integral molding is the development direction of advanced forming technology in the aerospace field. Taking a 3350mm diameter propellant tank bottom as an example, integral molding can eliminate 8 welds, with a total weld elimination length of nearly 25 meters. The weight reduction of a single tank bottom is close to 15 kg, thereby increasing the effective launch payload by nearly 60 kg and significantly improving the efficiency of the rocket structure. However, integral molding of large-sized thin-walled components increases the difficulty of forming local flange-like reinforcement features, making them highly susceptible to cracking defects or exceeding dimensional and positional accuracy tolerances, leading to the scrapping of the entire bottom product.

[0003] The main difficulties in forming local features on the entire bottom part are: poor shape and position accuracy of local features, decreased material mechanical properties due to local heating, difficulty in plastic deformation of aluminum alloy in a hard state, and high requirements for the versatility of forming equipment due to the presence of multiple local features on the entire bottom. Specifically: 1) The bottom of the box is a complex thin-walled curved surface part, a typical weakly rigid shell, and the free state reference of the bottom is difficult to identify, leading to difficulties in positioning during local forming. 2) The bottom material is age-hardened aluminum alloy, which has poor plasticity. The amount of plastic deformation in local hole drilling reaches about 30%, far exceeding the plastic deformation capacity of age-hardened aluminum alloy, thus making it prone to cracking defects during forming and difficult to form small or deep local geometric features. 3) While hot forming can improve plasticity, it easily leads to a decrease in material properties for age-hardened aluminum alloy, affecting the overall strength of the part. Therefore, precise control of the local temperature field of the part is required. The temperature gradient between the heated area and the non-heated area exceeds 200℃. For aluminum alloy, a good conductor of heat, controlling a large temperature gradient (200℃) over a short distance (50mm) is very difficult. 4) Artificially aged aluminum alloys experience a significant decline in performance over time due to external temperature influences, especially when the temperature exceeds the aging temperature. Therefore, achieving rapid and stable heating efficiency over a short distance with a large temperature gradient is extremely difficult when heating ultra-large parts locally. These forming challenges make it difficult to maintain mechanical properties and achieve precise forming of 4-meter-class ultra-large parts within a localized 0.1-meter area, limiting the application of integrated, monolithic forming models for ultra-large components.

[0004] To address the forming challenges of high-strength, low-plasticity, and difficult-to-deform materials, rapid heating forming methods have been proposed in the field of hot forming of sheet metal parts. The main heating methods include air furnace heating, electromagnetic induction heating, current heating, and mold heating. Air furnace heating and mold heating are mostly integral heating methods, offering advantages such as high temperature control precision, stable thermal field, and uniform and controllable performance. However, they suffer from drawbacks such as complex structural design and high energy consumption for heating ultra-large components. Electromagnetic induction and current heating methods can often perform localized heating, but their heating efficiency is limited by the material's physical properties such as conductivity, magnetic permeability, and resistivity. The heating effect is highly correlated with the part's geometry and structural characteristics. Furthermore, materials whose magnetic properties change after heating exhibit a Curie point, leading to unstable high-temperature heating efficiency. In addition, the skin effect can easily cause localized overheating, making material property control difficult for temperature-sensitive materials. Therefore, for lightweight alloy materials such as aluminum alloys and copper alloys with low resistance and good thermal conductivity, air furnace or mold heating methods are commonly used to ensure stable and controllable temperatures for metal parts. Summary of the Invention

[0005] The purpose of this invention is to provide a local heating forming device and method for the bottom of a 3-meter-class aerospace launch vehicle tank, in order to solve the problems of large-size integral thin-walled components being unable to be locally formed, forming crack defects, incompatibility of multiple product models, low forming stability, difficulty in temperature field control, low process reliability, and high cost.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: to provide a 3-meter-class aerospace launch vehicle tank bottom local heating and forming device, including a device positioning unit, a heating unit, a forming mold unit and a servo control system;

[0007] The positioning unit automatically aligns the part with the baseline and rotates and flips the part according to the set value, so that the area on the part that needs to be heated and formed reaches the lowest position of the part, and records the movement sequence; the heating unit converts electrical energy into heat energy and transfers the heat energy to the area on the part that needs to be heated through efficient conduction, and the temperature detection device serves as the control signal for the conversion of electrical energy into heat energy, thereby controlling the error of the temperature value on the part; after receiving the temperature signal measured by the heating unit, the forming mold unit starts to move, controls the displacement of the movement to the set value, completes the forming process, and sends a control signal to the positioning unit to return the part to zero, thereby completing the forming of one position;

[0008] For deformation of multiple areas on the bottom of the box, different rotation and flipping angle values ​​can be set in sequence, and the positioning, preheating loading, heating monitoring and forming processes can be repeated in conjunction with the corresponding forming mold to complete the deformation of different areas in sequence.

[0009] Furthermore, the heating unit uses a high heat-melting and high thermal conductivity material, and achieves localized heating of the part through heat conduction. The localized thermal field of the part can be precisely controlled by adjusting the temperature of the heating unit and designing the size of the heat conduction area.

[0010] Another technical solution of the present invention provides a method for the above-mentioned 3-meter-class space launch vehicle tank bottom local heating and forming device, comprising the following steps:

[0011] S1, Pre-installed positioning:

[0012] Place the part on the positioning fixture, align it with the reference line and clamp it firmly. Then, according to the preset value, rotate the part back to the position along the horizontal plane normal and then flip it over. After flipping it into place, fix the position.

[0013] S2, Preheating Loading:

[0014] Keeping the pre-positioned position unchanged, the heating unit is positioned at the lowest point of the part after it is fixed in place, and a certain pressure is applied through the heating unit accessory to tightly fit the part to the heating unit; the applied pressure remains unchanged during the preheating process.

[0015] S3. Heating and monitoring:

[0016] Keeping the pre-positioned part, the heating unit, and the applied pressure unchanged, the temperature change at the predetermined position is detected by the temperature measurement system, and the temperature data is generated and recorded.

[0017] S4, Local Forming

[0018] Keep the pre-positioned position of the part unchanged, keep the position of the heating unit unchanged, and when the detected temperature value reaches the set value, start the forming mold to move, causing the local heating area of ​​the part to deform. When the predetermined displacement value is reached, the forming ends and the part returns to its original position from the bottom positioning device.

[0019] Furthermore, when there are multiple local areas on the bottom of the box that need to be shaped, the positioning unit executes the process of steps S1-S4 in sequence according to the rotation and flipping angles of different areas as set values, thereby realizing the heating deformation of multiple areas.

[0020] Furthermore, in step S2, a pressure control method is adopted to design a negative curvature mating surface. By utilizing the elastic deformation of the thin-walled component under external force, the part and the heating unit are brought into zero-gap contact, thereby improving the heat conduction efficiency between the part and the heating unit and achieving a rapid heating effect.

[0021] Furthermore, in step S1, the part is one of the following: a thin-walled metal shell of revolution, a thin-walled cylindrical shell with a single curvature, or a thin-walled cylindrical component with a double curvature.

[0022] The beneficial effects achieved by the 3-meter-class aerospace launch vehicle propellant tank bottom local heating forming device and method provided by the present invention are as follows:

[0023] This invention achieves highly reliable forming of multiple local locations on box bottoms of different configurations using a single positioning, heating, and forming device. This effectively improves the forming limit of the material, optimizes the forming process of box bottom parts, significantly shortens the manufacturing cycle, and improves the consistency of box bottom part product quality. Simultaneously, the use of temperature, force, and precise angular position control enables digital control, thereby achieving quality control of the box bottom parts. By achieving localized flanging forming of the entire bottom product, compared to traditional forming methods, it eliminates problems such as residual stress, uneven performance, and contour deformation caused by welds on the box bottom part's main structure, thus improving the forming accuracy and service reliability of the box bottom parts. Attached Figure Description

[0024] The invention will be further described below with reference to the accompanying drawings:

[0025] Figure 1 This is a schematic diagram of the bottom parts of the storage tank;

[0026] Figure 2 This is a schematic diagram of the tank bottom part forming device provided in an embodiment of the present invention;

[0027] Figure 3(a) is a schematic diagram of the placement of the bottom parts of the storage tank;

[0028] Figure 3(b) is a schematic diagram of the horizontal position adjustment of the bottom parts of the storage tank;

[0029] Figure 3(c) is a schematic diagram of the height adjustment of the bottom components of the storage tank;

[0030] Figure 4 This is a schematic diagram of preheating loading provided in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of temperature detection according to an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the forming process provided in an embodiment of the present invention. Detailed Implementation

[0033] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed account of the 3-meter-class aerospace launch vehicle propellant tank bottom local heating forming device and method proposed in this invention. The advantages and features of this invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0034] Figure 1 The diagram shown is of the bottom component 1 of the storage tank. The bottom component 1 of the storage tank is a typical rotating shell, and the generatrix equation is a circle, an ellipse or an arbitrary spline curve.

[0035] Figure 2 The image shows a forming device for the bottom part of a storage tank. The forming equipment includes a positioning unit, a heating unit, a forming mold unit, and a servo control system.

[0036] Figure 3 shows a schematic diagram of the pre-assembly and positioning process. First, the support device is in a horizontal position, the bottom of the box is placed on the support ring 2 and adjusted to be concentric with it, and the circumferential baseline of the bottom of the box is aligned with the center of the support ring 2. Then, the bottom of the box is rotated to the center line in the horizontal direction by the support device. Then, the bottom of the box is flipped along the flipping axis so that the flipping hole position is at the lowest position. Then, the heating unit moves in the vertical direction until it is in close contact with the surface of the part. Finally, the flipping hole mold is installed so that it is tightly connected with the mold.

[0037] Figure 4 The diagram shows the preheating loading process. The heating unit is activated to rapidly heat the part to the set temperature. Then, appropriate pressure is applied to the punch to ensure that the part is in close contact with the heating unit, thereby improving the heat conduction effect and allowing the temperature of a local part to quickly reach the predetermined temperature.

[0038] Figure 5 As shown, temperature detection involves installing a contact thermometer on the upper side of the part and recording the temperature change curve. Once the holding time reaches the predetermined time, a start signal is sent to prepare for forming.

[0039] Figure 6 The diagram illustrates the forming process. Under hydraulic pressure, the flanging punch 3 undergoes vertical displacement, causing localized deformation of the material in the perforated part, thus completing the flanging process. Once the punch displacement reaches a set value, the heating unit moves downwards vertically until it is a certain distance away from the part. Then, the bottom of the box is rotated to a horizontal position by the support unit, preparing for the forming of the next hole. The flanging die 4 serves as both a flanging support platform and a heating platform, balancing the force exerted by the flanging punch on the localized area of ​​the bottom of the box. It also controls the final flanging size through a clearance fit with the flanging punch 3.

[0040] The shape of the part can be various rotating shells or single-curvature structural components;

[0041] The sheet metals described cover various heat-treated light metal alloys such as aluminum alloys, aluminum-lithium alloys, magnesium alloys, and copper.

[0042] The heating unit can be designed as a general-purpose or special-purpose unit according to the diameter of the borehole, and the temperature measuring device can be designed as a general-purpose or special-purpose device accordingly.

[0043] The present invention provides a method for localized heating and forming of tank bottoms, achieving highly reliable forming of multiple local locations on tank bottoms of different configurations using a single positioning, heating, and forming device. This effectively improves the forming limit of materials, optimizes the forming process of tank bottom parts, significantly shortens the manufacturing cycle, and improves the consistency of tank bottom part product quality. Simultaneously, the use of temperature, force, and precise angular position control enables digital control, thereby achieving quality control of tank bottom parts. By achieving localized flanging forming of the entire bottom product, compared to traditional forming methods, it eliminates problems such as residual stress, uneven performance, and contour deformation caused by welds on the tank bottom part's main structure, thus improving the forming accuracy and service reliability of the tank bottom parts.

[0044] The contents not described in detail in this specification are prior art known to those skilled in the art. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

A 1.3-meter-class space launch vehicle propellant tank bottom local heating and forming device, characterized in that, It includes a device positioning unit, a heating unit, a forming mold unit, and a servo control system; The positioning unit automatically aligns the part with the baseline and rotates and flips the part according to the set value, so that the area on the part that needs to be heated and formed reaches the lowest position of the part, and records the movement sequence; the heating unit converts electrical energy into heat energy and transfers the heat energy to the area on the part that needs to be heated through efficient conduction, and the temperature detection device serves as the control signal for the conversion of electrical energy into heat energy, thereby controlling the error of the temperature value on the part; after receiving the temperature signal measured by the heating unit, the forming mold unit starts to move, controls the displacement of the movement to the set value, completes the forming process, and sends a control signal to the positioning unit to return the part to zero, thereby completing the forming of one position; For deformation of multiple areas on the bottom of the box, different rotation and flipping angle values ​​can be set sequentially, and with the corresponding forming mold, the positioning, preheating loading, heating monitoring and forming processes can be repeated to complete the deformation of different areas in sequence; The heating unit uses high heat-melting and high thermal conductivity materials, and heats local parts of the part through heat conduction. The local thermal field of the part can be precisely controlled by adjusting the temperature of the heating unit and the size of the designed heat conduction area. The heating unit can be designed as a general-purpose or special-purpose unit according to the diameter of the borehole, and the temperature detection device can be designed as a general-purpose or special-purpose device accordingly.

2. The method of the 3-meter-class space launch vehicle tank bottom local heating and forming device as described in claim 1, characterized in that, Includes the following steps: S1, Pre-installed positioning: Place the part on the positioning fixture, align it with the reference line and clamp it firmly. Then, according to the preset value, rotate the part back to the position along the horizontal plane normal and then flip it over. After flipping it into place, fix the position. S2, Preheating Loading: Keeping the pre-positioned position unchanged, the heating unit is positioned at the lowest point of the part after it is fixed in place, and a certain pressure is applied through the heating unit accessory to tightly fit the part to the heating unit; the applied pressure remains unchanged during the preheating process. S3. Heating and monitoring: Keeping the pre-positioned part, the heating unit, and the applied pressure unchanged, the temperature change at the predetermined position is detected by the temperature measurement system, and the temperature data is generated and recorded. S4, Local Forming Keep the pre-positioned position of the part unchanged, keep the position of the heating unit unchanged, and when the detected temperature value reaches the set value, start the forming mold to move, causing the local heating area of ​​the part to deform. When the predetermined displacement value is reached, the forming ends and the part returns to its original position from the bottom positioning device. When multiple local areas of the bottom of the box need to be shaped, the positioning unit executes the process of steps S1-S4 in sequence according to the rotation and flipping angles of different areas as set values, thereby realizing the heating deformation of multiple areas. In step S2, a pressure control method is adopted to design a negative curvature mating surface. By utilizing the elastic deformation of the thin-walled component under external force, the part and the heating unit are brought into zero-gap contact, thereby improving the heat conduction efficiency between the part and the heating unit and achieving a rapid heating effect.

3. The method of the 3-meter-class space launch vehicle tank bottom local heating and forming device as described in claim 2, characterized in that, In step S1, the part is one of the following: a thin-walled metal shell of revolution, a thin-walled cylindrical shell with a single curvature, or a thin-walled cylindrical component with a double curvature.

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