A large thin-walled rotary metal workpiece forming device and method

Abstract

The application provides a large thin-walled rotary metal workpiece forming device and method. The large thin-walled rotary metal workpiece forming device is used for forming a prefabricated workpiece into a metal workpiece, and comprises: a rotary mechanism for fixing and rotating the prefabricated workpiece around an axis; a partial mold arranged below the prefabricated workpiece and acting on more than 1 / 36 of the circumference of the bottom of the forming part of the prefabricated workpiece, and used for limiting the bottom profile of the prefabricated workpiece to be consistent with the metal workpiece; a forming mechanism arranged above the prefabricated workpiece, matched with the partial mold, and used for forming the prefabricated workpiece through a driving force; and the width of the partial mold is greater than the width of the forming mechanism at the part where the partial mold is matched with the forming mechanism. The application rotates the prefabricated workpiece through the rotary mechanism, so that the prefabricated workpiece can be smoothly formed even under the premise of using a component mold to replace a complete mold, and the mold production cost of the large thin-walled rotary metal workpiece is greatly saved.

Description

Technical Field

[0001] This application belongs to the field of metal forming and manufacturing technology, and more specifically, relates to a large thin-walled rotary metal workpiece forming apparatus and method. Background Technology

[0002] Large-sized, thin-walled rotating components are widely used in the aerospace field, such as the bottom of rocket fuel tanks. The forming method for these components typically employs a "segmented forming + friction stir welding" process. Due to the long weld seams, this process suffers from long production cycles and low production efficiency. In recent years, hydroforming and spin forming processes have emerged, but these suffer from drawbacks such as large worktables, complex equipment, and high costs. High-efficiency, low-cost manufacturing of these components is of great significance to the development of the aerospace industry.

[0003] Conventional spinning forming involves fixing sheet metal or a pre-made blank onto a mandrel, rotating the spindle to rotate both the mandrel and the workpiece simultaneously, and applying pressure to the blank using spinning wheels, gradually bringing it closer to the mandrel to obtain the desired rotating part. This process has the following drawbacks: large-diameter heads are prone to instability during spinning, with wall thickness deviations exceeding 30% (thicker in the middle and thinner at the edges). Therefore, chemical milling or mechanical milling is required after forming. This process can lead to structural defects or high residual stress in the head material, causing additional deformation of the workpiece, and ultimately making it impossible to control accuracy.

[0004] Electromagnetic forming, as a high-speed forming method, can improve the forming limit of materials. However, when forming large-sized workpieces, traditional electromagnetic forming uses large coils or arrayed coils. Large coils have problems such as complex coil stress and easy damage to the forming coil. At the same time, arrayed coils have lower efficiency and are more complicated to control.

[0005] Currently, some existing technologies employ a method of pre-forming a conical part before further spinning. For example, patent document CN106424287A discloses a step-by-step precision spinning forming process for large thin-walled spherical heads. This method first forms a conical part, then fixes it on a spherical mandrel for multiple spinning passes to form a high-precision large spherical head. This patented method directly forms the conical part from a flat plate to the final spherical workpiece, resulting in significant workpiece deformation and thinning. Furthermore, manufacturing different models of large-sized rotating thin-walled components requires designing matching complete molds, leading to higher costs. Summary of the Invention

[0006] In view of the shortcomings of existing technologies and devices, the purpose of this application is to provide a large thin-walled rotary metal workpiece forming device and method, which aims to solve the technical problem of high production cost of existing large thin-walled rotary metal workpieces.

[0007] To achieve the above objectives, according to one aspect of this application, a large thin-walled rotary metal workpiece forming apparatus is provided for forming a pre-made workpiece into a metal workpiece, comprising: A rotary mechanism for fixing and rotating prefabricated workpieces about an axis; A mold is placed below the precast workpiece and acts on the bottom of the precast workpiece for forming part at more than 1 / 36 of the circumference, for limiting the bottom shape of the precast workpiece to a part of the mold that is consistent with the metal workpiece. A forming mechanism that is positioned above the precast workpiece, cooperates with the aforementioned mold, and shapes the precast workpiece by means of driving force; In the portion of the mold that mates with the forming mechanism, the width of the mold portion is greater than the width of the forming mechanism.

[0008] Preferably, the prefabricated workpiece is a conical part, the large end diameter of the conical part is greater than the long axis diameter of the partial mold, the small end diameter of the conical part is smaller than the inner hole diameter of the metal workpiece, and the height of the conical part is greater than the depth of the partial mold.

[0009] As a further preferred embodiment, the prefabricated workpiece is obtained by cutting and rolling a sheet metal and welding it.

[0010] As a further preferred embodiment, the thickness of the sheet metal is the same as that of the metal workpiece.

[0011] Preferably, the arc length of the partial mold in the minor axis direction is less than or equal to the arc length of the partial mold in the major axis direction, and the arc length of the partial mold in the major axis direction is less than 1 / 3 of the circumference of the preformed workpiece used for forming the part.

[0012] Preferably, the partial mold acts on more than 1 / 18 of the circumferential direction of the bottom of the preformed workpiece for forming the portion.

[0013] As a further preferred embodiment, the partial mold acts on more than 1 / 6 of the circumferential direction of the bottom of the preformed workpiece for forming the portion.

[0014] Preferably, the rotary mechanism includes: The upper rotary mechanism is used to fix the long shaft end of the prefabricated workpiece. And a lower rotary mechanism for fixing the short shaft end of the prefabricated workpiece; The upper rotary mechanism and the lower rotary mechanism have the same angular velocity when rotating the prefabricated workpiece around the axis.

[0015] Preferably, the forming mechanism uses electromagnetic induction, electro-hydraulic explosion, or wire electro-explosion to generate a driving force in a direction perpendicular to the top of the preform, so as to form the preform.

[0016] As a further preferred embodiment, the system also includes a robotic arm for changing the direction and position of the driving force exerted by the forming mechanism on the preformed workpiece.

[0017] According to another aspect of this application, a method for manufacturing metal workpieces using the aforementioned large thin-walled rotary metal workpiece forming apparatus is provided.

[0018] According to another aspect of this application, a metal workpiece manufactured using the above-described method is also provided.

[0019] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: 1. While using partial molds, the rotary mechanism rotates the precast workpiece, so that different parts of the precast workpiece are formed sequentially through partial molds; thus replacing the complete mold that requires a lot of cost, greatly saving the production cost of molds for large thin-walled rotary metal workpieces; 2. Since the forming mechanism does not need to form the metal workpiece in one go, but forms it while rotating the preform, the power capacity is reduced from the MJ level to the kJ level, which improves the scalability of the forming mechanism, especially when using electromagnetic forming. 3. Compared to directly deforming a flat blank into a metal workpiece, the deformation amount of a prefabricated workpiece into a metal workpiece is smaller, the workpiece is thinner, and the wall thickness distribution is more uniform. 4. Pre-fabricated workpieces are preferably obtained by shearing and rolling sheet metal. Sheet metal with a thickness similar to that of metal workpieces can be used for forming, eliminating the need for subsequent machining and greatly improving production efficiency. 5. The forming mechanism preferably adopts forming methods such as electromagnetic induction, electro-hydraulic explosion, and metal wire electric explosion pulse force, which are flexible and controllable, and do not require the press or other table of traditional forming equipment, greatly reducing the equipment's footprint and cost. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the metal workpiece when viewed along the central axis of this application; Figure 2 This is a schematic diagram of the structure of the metal workpiece when viewed from a direction perpendicular to the central axis. Figure 3 This is a schematic diagram of the structure of the large thin-walled rotary metal workpiece forming device of this application; Figure 4 This is a schematic diagram of the structure of the rotary mechanism in some embodiments of this application; Figure 5 These are schematic diagrams of the shapes of some molds in some embodiments of this application; Figure 6 This is a schematic diagram of the morphology of the metal workpiece and the prefabricated workpiece provided in the embodiments of this application; Figure 7 This is a schematic diagram of the design parameters of the prefabricated workpiece provided in the embodiments of this application.

[0021] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-rotating mechanism; 11-upper rotating mechanism; 12-lower rotating mechanism; 2-forming mechanism; 3-prefabricated workpiece; 4-partial mold; 5-metal workpiece. Detailed Implementation

[0022] For ease of understanding, some terms used in this specific embodiment are defined as follows: Metal workpiece: In this application, it specifically refers to a large, thin-walled, rotating metal workpiece, which has a thin-walled, curved surface of revolution and appears circular when viewed along its central axis, such as... Figure 1 As shown, when viewed from the central axis perpendicular to the thin-walled surface of revolution, it appears bowl-shaped, as... Figure 2 As shown; some metal workpieces have round holes at the bottom, which are not shown in the figure; Prefabricated workpiece: In the embodiments of this application, the material of the metal workpiece can be obtained by processing a large thin-walled rotary metal workpiece forming device. The shape and size are usually similar to the metal workpiece, but a certain amount of allowance is left at the edge to facilitate subsequent shearing. Complete mold: A mold used in the prior art to form a pre-made workpiece, typically with a top shape and size almost identical to the metal workpiece; Z-axis: In this application, it is defined as an axis parallel to the centerline of the metal workpiece; XY plane: In this application, it is defined as a plane perpendicular to the Z-axis; Bottom: The bowl-shaped exterior of the metal workpiece; Top: The bowl-shaped interior of a metal workpiece; Major axis direction: the direction close to the upper edge of the bowl-shaped part of the metal workpiece; Short axis direction: The direction closest to the intersection of the central axis and the bottom of the metal workpiece; The definitions of the corresponding terms for metal workpieces can also be used for the bottom, top, major axis direction, and minor axis direction of complete molds, partial molds, and prefabricated workpieces; It should be understood that the terms "top," "bottom," "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," "X-axis," "Y-axis," "Z-axis," "XY plane," "XZ plane," and "YZ plane," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] This application provides a large thin-walled rotary metal workpiece forming apparatus for obtaining metal workpieces from pre-made workpieces. The pre-made workpiece is not part of the large thin-walled rotary metal workpiece forming apparatus; it is typically a tapered part with a shape close to that of the metal workpiece, obtained by shearing, rolling, and welding a sheet metal of similar thickness. The large end diameter of the tapered part is larger than the major axis diameter of the partial mold, the small end diameter is smaller than the inner diameter of the metal workpiece, and the height of the tapered part is greater than the depth of the partial mold to allow for additional shearing and processing later. It should be noted that the forming apparatus of this application is applicable even to large thin-walled rotary metal workpieces without an inner hole. In the design, the relatively flat bottom portion can be independently designed as a metal disc; the area where the metal disc is removed is the inner hole. During final forming, the metal disc is welded to the metal workpiece obtained by the method of this application.

[0025] The large thin-walled rotary metal workpiece forming device includes the following structure, such as Figure 3 As shown: A rotary mechanism 1 for fixing and rotating the prefabricated workpiece 3 about the axis; Located below the preformed workpiece 3, acting on the bottom of the preformed workpiece 3 for forming part at more than 1 / 36 of the circumference, for limiting the bottom shape of the preformed workpiece 3 to a part of the mold that is consistent with the metal workpiece. The forming mechanism 2 is positioned above the precast workpiece 3 and generates driving force in a direction perpendicular to the top of the precast workpiece 3. It cooperates with the partial mold 4 to form the precast workpiece 3. In the part where the partial mold 4 cooperates with the forming mechanism 2, the width of the partial mold 4 is greater than the width of the forming mechanism 2, so as to ensure that the forming mechanism 2 does not cause deformation of the preformed workpiece 3 when it generates a driving force on the preformed workpiece 3 from the top of the preformed workpiece 3.

[0026] In some embodiments, to more firmly fix the prefabricated workpiece 3 and ensure its uniform rotation, the rotary mechanism 1 includes: The upper rotary mechanism 11 is used to fix the long shaft end of the prefabricated workpiece 3; And a lower rotary mechanism 12 for fixing the short shaft end of the prefabricated workpiece 3, wherein the upper rotary mechanism 11 and the lower rotary mechanism 12 have the same angular velocity when rotating the prefabricated workpiece 3 about the axial direction.

[0027] In some embodiments, the upper rotary mechanism 11 and the lower rotary mechanism 12 are coaxial and annular. The pre-made workpiece 3 is fixed to the rotary mechanism by means of a pressure ring, etc. As the upper rotary mechanism 11 and the lower rotary mechanism 12 rotate synchronously and coaxially, it is gradually formed by a portion of the mold 4 and the forming mechanism 2, such as... Figure 4 As shown.

[0028] The principle of the partial mold 4 and the forming mechanism 2 is as follows: they cooperate with each other, first acting on a certain area of ​​a fan-shaped portion of the prefabricated workpiece 3; then changing their relative position with the prefabricated workpiece 3 around the axial direction, acting on the corresponding areas of the remaining fan-shaped portions, until all areas of all fan-shaped portions of the prefabricated workpiece 3 are completely formed. Therefore, the wider the area that the partial mold 4 acts on the prefabricated workpiece 3 at one time, the faster the forming speed, and the narrower the area, the more cost-effective it is. From the perspective of cost saving, in some embodiments, the arc length (or length) of the partial mold 4 in the long axis direction is less than 1 / 3 of the circumference of the prefabricated workpiece 3 used for forming the portion; from the perspective of forming speed, in some embodiments, the partial mold 4 acts on more than 1 / 18 of the circumference of the bottom curved surface of the prefabricated workpiece 3 used for forming the portion; in other embodiments, the partial mold 4 acts on more than 1 / 6 of the circumference of the bottom curved surface of the prefabricated workpiece 3 used for forming the portion.

[0029] In some embodiments, to ensure the smooth forming of the prefabricated workpiece 3, the actual area of ​​a portion of the mold 4 is slightly larger than the area acting on the prefabricated workpiece 3. However, since the arc length (or length) in the minor axis direction is smaller than the arc length (or length) in the major axis direction, the portion of the mold 4 can be made in a shape where the arc length (or length) in the minor axis direction is less than or equal to the arc length (or length) in the major axis direction, such as an isosceles trapezoid, an isosceles triangle, or a rectangle. It should be noted that the above shapes are the shapes of the portion of the mold 4 projected onto the XY plane or when unfolded. In the device of this application, to ensure the forming of the prefabricated workpiece 3, the portion of the mold 4 has a certain curvature from the major axis direction to the minor axis direction. In some embodiments, to facilitate the fabrication of the portion of the mold 4, the portion of the mold 4 is designed as a rectangle, such as... Figure 5 As shown.

[0030] Since the forming mechanism 2 is usually unable to act on the entire fan-shaped portion of the mold 4 for forming at one time, in some embodiments, the large thin-walled rotary metal workpiece forming device also includes a robotic arm for changing the direction and position of the force applied by the forming mechanism 2 to the preformed workpiece 3, which is not shown in the figure.

[0031] This large, thin-walled rotary metal workpiece forming apparatus can be used to manufacture metal workpieces. In some embodiments, the workflow is as follows: (1) First, according to the final shape of the required metal workpiece, a plate with a thickness similar to that of the metal workpiece is processed into a prefabricated workpiece by rolling, bending and welding. (2) The preformed workpiece is fixed to the rotary mechanism by the pressure ring. The forming mechanism generates a driving force that cooperates with part of the mold by means of electromagnetic induction, electro-hydraulic explosion or metal wire electric explosion. This driving force can generate pressure or partial pressure in the direction perpendicular to the top of the preformed workpiece. If necessary, the mechanical arm is used to move the position and direction of the forming mechanism until a fan-shaped part of the preformed workpiece is formed. (3) The rotary mechanism drives the precast workpiece to rotate, changing the interaction position between the precast workpiece and some molds and forming mechanism, so that a fan-shaped part of the precast workpiece is formed again; this process is repeated until all parts of the precast workpiece used for forming are completely formed by the forming mechanism and some molds, becoming a metal workpiece. In a certain part of the prefabricated workpiece used for forming, a fan-shaped part can be formed at once; in other embodiments, in step (3), the prefabricated workpiece can also be driven by a rotary mechanism. After the mold and forming mechanism work together to form the prefabricated workpiece at a certain height, the height and direction of the driving force generated by the forming mechanism can be changed by a robotic arm until it is finally finely formed into a metal workpiece.

[0032] The following is an example: This embodiment discloses a method for manufacturing a large thin-walled rotary metal workpiece forming device, which uses a rotary mechanism, a forming mechanism, and a mold to manufacture a pre-made workpiece into a finished product.

[0033] Taking the metal workpiece 5 at the bottom of a semi-ellipsoidal rocket fuel tank as an example, its parameters are an ellipsoid with a major axis of 3350 mm and a semi-axial length of 2240 mm. Therefore, we designed a prefabricated workpiece 3 that meets the requirements. Using sheet metal, through rolling, bending, and welding processes, the prefabricated workpiece 3 is prefabricated to the shape described above, such as... Figure 6 As shown.

[0034] Pre-fabricated workpiece 3 is a conical part with a large end diameter of 3799mm, a small end diameter of 200mm, and a height of 1274mm. Figure 7 As shown; while part of the mold 4 has a major axis of 3350mm and a minor axis of 1120mm, which is part of the curved surface.

[0035] The prefabricated workpiece 3 is fixed on the rotary mechanism 1; the forming mechanism 2 in this embodiment uses an electromagnetic force drive method to drive the prefabricated workpiece 3 to deform and form.

[0036] The forming mechanism 2 drives the preformed workpiece 3 to deform, and the partial mold 4 is used to limit the forming shape of the preformed workpiece; the rotary mechanism 1 drives the preformed workpiece 3 to rotate through the motor reduction mechanism until the preformed workpiece 3 is formed into the outline of the metal workpiece 5.

[0037] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0040] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A large-scale thin-walled rotary metal workpiece forming device, used to form a pre-made workpiece into a metal workpiece, characterized in that, include: A rotary mechanism for fixing and rotating prefabricated workpieces about an axis; A mold is placed below the precast workpiece and acts on the bottom of the precast workpiece for forming part at more than 1 / 36 of the circumference, for limiting the bottom shape of the precast workpiece to a part of the mold that is consistent with the metal workpiece. A forming mechanism that is positioned above the precast workpiece, cooperates with the aforementioned mold, and shapes the precast workpiece by means of driving force; In the portion of the mold that mates with the forming mechanism, the width of the mold portion is greater than the width of the forming mechanism. The prefabricated workpiece is a tapered part, the large end diameter of the tapered part is larger than the long axis diameter of the partial mold, the small end diameter of the tapered part is smaller than the inner hole diameter of the metal workpiece, and the height of the tapered part is greater than the depth of the partial mold. The rotary mechanism includes: an upper rotary mechanism for fixing the long shaft end of the preformed workpiece, and a lower rotary mechanism for fixing the short shaft end of the preformed workpiece; the upper rotary mechanism and the lower rotary mechanism have the same angular velocity when rotating the preformed workpiece around the axial direction. The forming mechanism uses electromagnetic induction, electro-hydraulic explosion, or metal wire electro-explosion to generate a driving force in a direction perpendicular to the top of the preform, so as to form the preform.

2. The large thin-walled rotary metal workpiece forming apparatus as described in claim 1, characterized in that, The prefabricated workpiece is obtained by cutting, rolling, and welding sheet metal.

3. The large thin-walled rotary metal workpiece forming apparatus as described in claim 1, characterized in that, The arc length of the partial mold in the short axis direction is less than or equal to the arc length of the partial mold in the long axis direction, and the arc length of the partial mold in the long axis direction is less than 1 / 3 of the circumference of the preformed workpiece used for forming the part.

4. The large thin-walled rotary metal workpiece forming apparatus as described in claim 1, characterized in that, The mold portion acts on more than 1 / 18 of the circumference of the bottom of the preformed workpiece for forming the portion.

5. The large thin-walled rotary metal workpiece forming apparatus as described in claim 4, characterized in that, The molded portion acts on more than 1 / 6 of the circumferential portion of the bottom of the preformed workpiece used for forming.

6. The large thin-walled rotary metal workpiece forming apparatus according to any one of claims 1-5, characterized in that, It also includes a robotic arm for changing the direction and position of the driving force of the forming mechanism on the preformed workpiece.

7. A method for manufacturing a metal workpiece using the large thin-walled rotary metal workpiece forming apparatus according to any one of claims 1-6.

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