Thin-walled high rib ring-cylinder envelope forming method capable of controlling high rib growth and forming load

Abstract

The present application relates to a kind of thin-walled high rib ring cylinder envelope forming method of controllable high rib growth and forming load, comprising the following steps: ring blank is loaded into constraint mould, it is attached with the inner circumferential surface of constraint mould, ensure that ring blank outer diameter is invariable;Two ring baffles are fixed at the two ends of constraint mould respectively, it is coaxial with constraint mould, ensure that ring blank height is invariable;Envelope mould is loaded in constraint mould, it is attached with the inner circumferential surface of ring blank, simultaneously make envelope mould axis and constraint mould axis parallel;Under the joint action of constraint mould, envelope mould and two ring baffles, envelope geometry movement relationship is formed between envelope mould and ring blank along circumferential direction and axial direction, make ring blank occur continuous local plastic deformation, until ring blank inner circumferential surface high rib is completely enveloped and formed by envelope mould.The present application can realize thin-walled high rib ring cylinder near net forming, its manufacturing efficiency is high, material utilization is high, can refine grain and form continuous metal streamline simultaneously, to greatly improve the mechanical properties of thin-walled high rib ring cylinder.

Description

Technical Field

[0001] This invention relates to the field of integral forming methods for thin-walled, high-ribbed ring cylinders, and more specifically, to an envelope forming method for thin-walled, high-ribbed ring cylinders that can control the growth of high ribs and the forming load. Background Technology

[0002] Thin-walled, highly ribbed ring cylinders are critical load-bearing components in aerospace and launch vehicles. These structures feature thin webs, high and wide ribs, and are made from lightweight, high-strength, and difficult-to-machine materials, making high-performance and high-efficiency manufacturing challenging. Currently, these components are primarily manufactured through machining. However, machining requires the removal of a significant amount of material, resulting in low processing efficiency, low material utilization, severe product deformation, and disruption of metal flow lines. Therefore, machining cannot meet the high-performance and high-efficiency manufacturing requirements of thin-walled, highly ribbed ring cylinders. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for enveloping and forming thin-walled high-rib ring cylinders with controllable high-rib growth and forming load, thereby realizing high-performance and high-efficiency manufacturing of thin-walled high-rib ring cylinders.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: A method for enveloping and forming a thin-walled high-rib ring cylinder with controllable high-rib growth and forming load is constructed. The forming device includes a constraint mold, an annular baffle, and an enveloping mold. The constraint mold consists of two semi-circular rings, with the inner radius of the constraint mold equal to the outer radius of the ring blank, and the axial height of the constraint mold equal to the axial height of the ring blank. The enveloping mold includes a gourd-shaped loading area and two cylindrical clamping areas. A cavity for forming high ribs is provided on the outer surface of the loading area. The two clamping areas are located at both ends of the loading area and connected to the drive mechanism of the enveloping forming device. The two clamping areas are coaxial with the loading area. The generatrix of the outer contour of the loading area is arc-shaped, and the length of the generatrix is ​​equal to the axial length of the loading area of ​​the thin-walled high-rib ring cylinder. The single-sided distance between the clamping area of ​​the enveloping mold and the outer contours at both ends of the loading area is greater than the target rib height of the thin-walled high-rib ring cylinder.

[0005] The forming method includes the following steps:

[0006] The ring blank is inserted into the constraint mold, ensuring it fits against the inner circumferential surface of the mold and maintaining a constant outer diameter. Two annular baffles are fixed at both ends of the constraint mold, coaxial with it, ensuring a constant height of the ring blank. The enveloping mold is placed inside the constraint mold, fitting against the inner circumferential surface of the ring blank, with its axis parallel to the constraint mold axis. The constraint mold drives the ring blank and the two annular baffles to rotate around its own axis at a speed of w1. The enveloping mold performs multi-degree-of-freedom motion: it feeds radially along the ring blank at a speed of v1 and rotates around its own axis at a speed of w2. The ring blank rotates while simultaneously rolling back and forth in the plane passing through the axis of the enveloping mold and the axis of the constraining mold. This back-and-forth rolling can be decomposed into a rotational motion around the center of the arc generatrix of the enveloping mold and the ring blank at an angular velocity of w3, and a translational motion along the axis of the constraining mold at a velocity of v2. Under the combined action of the constraining mold, the enveloping mold, and the two annular baffles, an enveloping geometric motion relationship is formed between the enveloping mold and the ring blank in both the circumferential and axial directions, causing the ring blank to undergo continuous local plastic deformation until the high ribs on the inner circumferential surface of the ring blank are completely enveloped and formed by the enveloping mold.

[0007] According to the above scheme, the method for designing the loading region cavity of the envelope mold includes the following steps:

[0008] The transverse rib cavity of the envelope mold is designed based on the axial reverse envelope principle of the thin-walled high-rib ring cylinder. A rectangular coordinate system S0 is established with the position of the envelope mold contacting the middle of the inner wall of the ring blank as a reference, and the center of the arc generatrix contacting the inner wall of the ring blank as the origin O. The z-axis of this rectangular coordinate system is parallel to the axis of the constraint mold, and the x-axis lies in a plane passing through the axis of the envelope mold and the axis of the constraint mold. An axial section without longitudinal ribs is cut along the x-axis on the thin-walled high-rib ring cylinder, and a point P1(x1,z1) is arbitrarily selected on the inner contour line of this axial section. Point P1 is first moved downwards along the axial direction by L to the upper limit position of the loading area of ​​the thin-walled high-rib ring cylinder, and simultaneously oscillates clockwise by θ / 2 around the center of the arc generatrix contacting the inner wall of the ring blank. The following relationship is satisfied between L and θ:

[0009]

[0010] Where L is 1 / 2 of the axial length of the loading zone of the thin-walled high-ribbed ring cylinder, and θ is the angle by which the envelope mold swings from the upper limit position of the loading zone of the thin-walled high-ribbed ring cylinder to its lower limit position;

[0011] In the rectangular coordinate system S0, point P1 moves along the z-direction with velocity v2 for time t. At this time, point P1 moves to point P2, the rectangular coordinate system S0 moves to S1, and the origin O moves to point O'. Simultaneously, in the rectangular coordinate system S1, point P2 is rotated around point O' with angular velocity -w3 for time t, causing point P2 to move to point P3 (x3, z3). During the process of the envelope module moving from the middle position of the loading area of ​​the thin-walled high-ribbed annular cylinder to its lower limit position, the motion trajectory equation of any point on the inner contour line of the axial section in the coordinate system S0 is:

[0012]

[0013] Where x1 is the x-coordinate value of any point on the inner contour line of the above-mentioned axial section in the coordinate system S0, z1 is the z-coordinate value of any point on the inner contour line of the above-mentioned axial section in the coordinate system S0, x3 is the x-coordinate value of any point on the inner contour line of the above-mentioned axial section in the coordinate system S0 at time t, and z3 is the z-coordinate value of any point on the inner contour line of the above-mentioned axial section in the coordinate system S0 at time t.

[0014] During the process of the envelope mold moving from the lower limit position to the upper limit position of the loading zone of the thin-walled, high-ribbed annular cylinder, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is:

[0015]

[0016] During the process of the envelope mold moving from the upper limit position of the loading zone of the thin-walled, high-ribbed annular cylinder to its middle position, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is:

[0017]

[0018] Discretize the inner contour line of the axial section of the thin-walled, highly ribbed ring cylinder into a point cloud P. s ={P1,P2,P3…P n} Calculate the motion trajectory of all points in the point cloud according to the established motion trajectory equation, and draw the trajectory curves of all points undergoing axial anti-envelope motion, thus forming a family of curves C of axial anti-envelope motion trajectories. s ={C1,C2,C3…C n The inner contour line enclosed by the family of curves is the contour line of the transverse rib cavity of the envelope mold; combined with the inner contour line of the transverse rib cavity of the envelope mold, the transverse rib cavity is machined on the loading area of ​​the envelope mold to ensure that the envelope mold does not interfere with the transverse ribs of the thin-walled high-rib ring cylinder.

[0019] Obtain the inner contour line of the longitudinal rib cavity of the envelope mold; combine the inner contour line of the longitudinal rib cavity of the envelope mold, and machine the longitudinal rib cavity on the surface of the loading area of ​​the envelope mold to ensure that the envelope mold does not interfere with the longitudinal ribs of the thin-walled high-rib ring cylinder.

[0020] According to the above scheme, the design method for the envelope mode motion is as follows:

[0021] In the multi-degree-of-freedom envelope forming process of thin-walled high-rib ring cylinder, the envelope die first rolls upward along the axial direction to the upper limit position of the loading area of ​​the thin-walled high-rib ring cylinder, then rolls downward along the axial direction to the lower limit position of the loading area of ​​the thin-walled high-rib ring cylinder, and then rolls upward along the axial direction to the middle of the loading area of ​​the thin-walled high-rib ring cylinder. The above process is exactly one axial rolling cycle of the envelope die; one rotation of the constraint die is exactly one envelope forming pass; in order to ensure the surface quality of the thin-walled high-rib ring cylinder, the rolling direction of the envelope die needs to be changed between adjacent envelope forming passes.

[0022] To maintain a pure rolling motion relationship between the enveloping die and the inner wall of the ring blank, the rotational speed w1 of the constraint die and the rotational speed w2 of the enveloping die must satisfy the following relationship:

[0023]

[0024] Where r1 is the inner radius of the ring blank, and r2 is the maximum radius of the loading area of ​​the envelope mold;

[0025] Meanwhile, the angular velocity w3 of the envelope mold about the center of the arc generatrix in contact with the annular blank and its moving speed v2 along the axial direction of the constraint roller satisfy the following relationship:

[0026] v2=w3R (6)

[0027] Where R is the radius corresponding to the generatrix of the circular arc in the envelope loading region;

[0028] To ensure that the envelope die returns to its initial position at the end of each envelope forming pass, the following kinematic relationship should be satisfied between the envelope die and the constraint die:

[0029]

[0030] Where L is half the distance from the upper limit point to the lower limit point of the loading zone of the thin-walled, high-strength ring cylinder.

[0031] According to the above scheme, the outer radius of the annular baffle is equal to the outer radius of the constraint mold, and the inner radius of the annular baffle is smaller than the inner radius of the web of the thin-walled, high-ribbed annular cylinder.

[0032] According to the above scheme, the difference between the inner radius of the web of the thin-walled high-ribbed ring cylinder and the inner radius of the annular baffle is greater than the target rib height of the thin-walled high-ribbed ring cylinder, and the difference between the inner radius of the web of the thin-walled high-ribbed ring cylinder and the inner radius of the annular baffle is less than the single-sided distance between the two ends of the outer contour of the envelope mold clamping area and the loading area.

[0033] The thin-walled, high-ribbed ring forming method of the present invention, which allows for controllable high-rib growth and forming load, has the following beneficial effects:

[0034] 1. The present invention provides a high-performance, high-efficiency, multi-degree-of-freedom envelope forming method for thin-walled high-ribbed ring cylinders that can control the growth of high ribs and reduce forming load. This method can achieve near-net-shape forming of thin-walled high-ribbed ring cylinders, with high manufacturing efficiency and high material utilization. At the same time, it can refine grains and form continuous metal flow lines, thereby significantly improving the mechanical properties of thin-walled high-ribbed ring cylinders.

[0035] 2. The high-performance, high-efficiency, multi-degree-of-freedom enveloping forming method for thin-walled high-ribbed ring cylinders that can control the growth of high ribs and reduce forming load can significantly reduce the contact area between the enveloping mold and the ring blank, thereby significantly reducing the forming load.

[0036] 3. The high-performance, high-efficiency, multi-degree-of-freedom envelope forming method for thin-walled high-rib ring cylinders that can control the growth of high ribs and reduce forming load can realize multi-degree-of-freedom movement of the envelope mold, control the flow pattern of metal inside the ring blank, and control the deformation of the ring blank along the circumferential and axial directions, thereby achieving precise control of the rib height and anisotropic properties of the thin-walled high-rib ring cylinder.

[0037] 4. The high-performance, high-efficiency, multi-degree-of-freedom envelope forming method for thin-walled high-rib ring cylinders that can control the growth of high ribs and reduce the forming load of the present invention has good versatility. It can realize high-performance, high-efficiency, multi-degree-of-freedom envelope forming of various types of thin-walled high-rib ring cylinders, such as thin-walled mesh rib ring cylinders, thin-walled transverse rib ring cylinders, and thin-walled longitudinal rib ring cylinders. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0039] Figure 1 Schematic diagram of a thin-walled mesh-reinforced ring cylinder;

[0040] Figure 2 This is a schematic diagram of a ring-shaped billet;

[0041] Figure 3 A schematic diagram illustrating the multi-degree-of-freedom envelope forming principle of a thin-walled mesh-reinforced ring cylinder;

[0042] Figure 4 Exploded view of a multi-degree-of-freedom envelope forming mechanism for a thin-walled mesh-reinforced ring cylinder;

[0043] Figure 5 A schematic diagram of the envelope motion trajectory of the enveloped model on the circumferential unfolded diagram of the thin-walled mesh-reinforced annular cylinder;

[0044] Figure 6 A schematic diagram of the axial reverse envelope principle of the axial section of a thin-walled mesh-reinforced ring cylinder;

[0045] Figure 7 The contour of the transverse rib cavity of the envelope mold obtained by the principle of axial reverse envelope;

[0046] Figure 8A schematic diagram illustrating the principle of creating the horizontal and vertical rib cavities of the envelope mold;

[0047] Figure 9 The angular velocity of the oscillation mold and its axial movement speed along the constraint mold are set for the multi-degree-of-freedom envelope forming process of thin-walled mesh-reinforced ring cylinder.

[0048] Figure 10 The variation law of the outer contour during the multi-degree-of-freedom envelope forming process of thin-walled mesh-reinforced ring cylinder;

[0049] Figure 11 This study investigates the variation law of radial load on the envelope mold during the multi-degree-of-freedom envelope forming process of a thin-walled mesh-reinforced ring cylinder. Detailed Implementation

[0050] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0051] Figure 1 This is a three-dimensional schematic diagram of the thin-walled mesh-reinforced annular cylinder in the example. It consists of one annular cylindrical web, four transverse reinforcements and twelve longitudinal reinforcements. The spacing between adjacent transverse reinforcements is equal, and the twelve longitudinal reinforcements are evenly distributed along the inner circumference of the annular cylindrical web. Figure 2 This is a 3D schematic diagram of the ring blank required for the thin-walled mesh-reinforced ring cylinder in this example. The dimensions of the thin-walled mesh-reinforced ring cylinder and the ring blank in this example are shown in Table 1.

[0052] Table 1. Dimensions of the thin-walled mesh-reinforced ring cylinder and the ring blank in this example.

[0053]

[0054] A high-performance, high-efficiency, multi-degree-of-freedom envelope forming method for thin-walled, highly ribbed ring cylinders that can control the growth of ribs and reduce forming load includes the following steps:

[0055] S1. Insert the ring blank 3 into the constraint mold 4, ensuring it fits against the inner circumferential surface of the constraint mold 4, thus maintaining the outer diameter of the ring blank 3. Fix the annular baffle 2 and annular baffle 5 to both ends of the constraint mold 4, ensuring they are coaxial with the constraint mold 4, thus maintaining the height of the ring blank 3. Insert the enveloping mold 1 into the constraint mold 4, ensuring it fits against the inner circumferential surface of the ring blank 3, while simultaneously ensuring the axis of the enveloping mold 1 is parallel to the axis of the constraint mold 4.

[0056] S2, the constraint mold 4 drives the ring blank 3, annular baffle 2, and annular baffle 5 to rotate around their own axis at a speed of w1. The enveloping mold 1 performs multi-degree-of-freedom motion: it translates radially along the ring blank at a speed of v1, rotates around its own axis at a speed of w2, and simultaneously rolls back and forth in a plane passing through the axis of the enveloping mold 1 and the axis of the constraint mold 4. This back-and-forth rolling can be decomposed into rotational motion around the center of the arc generatrix of the contact between the enveloping mold 1 and the ring blank 3 at an angular velocity of w3, and back-and-forth translational motion along the axial direction of the constraint mold 4 at a speed of v2. Under the combined action of the constraint mold 4, the enveloping mold 1, the annular baffle 2, and the annular baffle 5, an enveloping motion relationship is formed between the enveloping mold 1 and the ring blank 3 in both the circumferential and axial directions, causing continuous local plastic deformation of the ring blank until the longitudinal and transverse ribs on the inner circumferential surface of the ring blank are completely enveloped and formed by the enveloping mold.

[0057] S3, Constraint mold 4 design: The constraint mold 4 consists of two semicircular rings, which is to facilitate the thin-walled high-rib ring cylinder 6 to detach from the constraint mold 4. The inner radius of the two semicircular rings is equal to the outer radius of the ring blank 3, and the axial height of the two semicircular rings is equal to the axial height of the ring blank 3.

[0058] S4, Structural Design of Enveloping Mold 1: Enveloping mold 1 includes a gourd-shaped loading area and two cylindrical clamping areas. The outer surface of the loading area has cavities for forming longitudinal and transverse ribs. The two clamping areas are located at both ends of the loading area and connected to the drive mechanism of the enveloping forming equipment. The two clamping areas are coaxial with the loading area, and the generatrix of the outer contour of the loading area is arc-shaped. The length of the generatrix of the outer contour of the loading area is equal to the axial length of the loading area of ​​the thin-walled high-rib ring cylinder 6. To ensure that the clamping areas of enveloping mold 1 do not interfere with the longitudinal and transverse ribs, the single-side distance between the clamping areas of enveloping mold 1 and the outer contours at both ends of the loading area is greater than the target rib height of the thin-walled high-rib ring cylinder 6. When designing the diameter of the clamping areas of enveloping mold 1, it is necessary to ensure that the clamping areas do not interfere with the inner walls of the annular baffles 2 and 5 during the movement of enveloping mold 1, and also to ensure that the clamping areas do not break during the multi-degree-of-freedom enveloping forming process of the thin-walled mesh-rib ring cylinder 6. Designing the loading surface of the loading area of ​​the enveloping mold 1 as an arc surface has the following functions: 1) It significantly reduces the contact area between the enveloping mold 1 and the ring blank 3, thereby significantly reducing the radial load on the enveloping mold 1; 2) It enables the enveloping mold 1 to perform circumferential and axial rolling on any position of the inner wall of the ring blank 3, thereby realizing the multi-degree-of-freedom enveloping forming of the thin-walled high-rib ring cylinder 6; 3) It makes the movement mode of the enveloping mold 1 easy to control, thereby controlling the metal flow mode inside the ring blank 3 and the deformation of the ring blank 3 along the circumferential and axial directions, thereby realizing the precise control of the rib height and anisotropic properties of the thin-walled mesh-rib ring cylinder 6.

[0059] S5, Design of the loading area cavity of envelope mold 1: In order to ensure that the loading area cavity of envelope mold 1 does not interfere with the longitudinal and transverse ribs, the cavity in the loading area of ​​envelope mold 1 needs to be designed according to the following steps.

[0060] S51, the transverse rib cavity of the envelope mold 1 is designed based on the axial reverse envelope principle of the thin-walled mesh-reinforced annular cylinder 6. Taking the position where the envelope mold 1 contacts the middle of the inner wall of the annular blank 3 as a reference, and establishing a rectangular coordinate system S0 with the center of the arc generatrix contacting the inner wall of the annular blank 3 as the origin O, the z-axis of this rectangular coordinate system is parallel to the axis of the constraint mold 4, and the x-axis of this rectangular coordinate system lies in the plane passing through the axis of the envelope mold 1 and the axis of the constraint mold 4. An axial section without longitudinal ribs is cut along the x-axis on the thin-walled mesh-reinforced annular cylinder 6, and a point P1(x1,z1) is arbitrarily selected from the inner contour line of this axial section. Point P1 is first moved downwards along the axial direction by L to the upper limit position of the loading area of ​​the thin-walled mesh-reinforced annular cylinder 6, and simultaneously oscillates clockwise by θ / 2 around the center of the arc generatrix contacting the inner wall of the annular blank 3. The following relationship is satisfied between L and θ:

[0061]

[0062] Where L is half of the axial length of the loading area of ​​the thin-walled mesh ring cylinder 6, and θ is the angle at which the envelope mold 1 swings from the upper limit position of the loading area of ​​the thin-walled mesh ring cylinder 6 to its lower limit position.

[0063] In the rectangular coordinate system S0, point P1 moves along the z-direction with velocity v2 for time t. At this time, point P1 moves to point P2, the rectangular coordinate system S0 moves to S1, and the origin O moves to point O'. Simultaneously, in the rectangular coordinate system S1, point P2 rotates around point O' with angular velocity -w3 for time t, causing point P2 to move to point P3 (x3, z3). During the process of the envelope module 1 moving from the middle position of the loading area of ​​the thin-walled mesh ring cylinder 6 to its lower limit position, the trajectory equation of any point on the inner contour line of the axial section in the coordinate system S0 is:

[0064]

[0065] Where x1 is the x-coordinate value of any point on the inner contour line of the aforementioned axial section in the coordinate system S0, z1 is the z-coordinate value of any point on the inner contour line of the aforementioned axial section in the coordinate system S0, x3 is the x-coordinate value of any point on the inner contour line of the aforementioned axial section in the coordinate system S0 at time t, and z3 is the z-coordinate value of any point on the inner contour line of the aforementioned axial section in the coordinate system S0 at time t.

[0066] During the process of the envelope module 1 moving from the lower limit position of the loading area of ​​the thin-walled mesh ring cylinder 6 to its upper limit position, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is:

[0067]

[0068] During the process of the envelope module 1 moving from the upper limit position of the loading area of ​​the thin-walled mesh ring cylinder 6 to its middle position, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is:

[0069]

[0070] Formulas (4)-(6) are the axial reverse envelope motion trajectory equations for any point on the inner contour line of the axial section of the thin-walled mesh-reinforced ring cylinder 6. The inner contour line of the axial section of the thin-walled mesh-reinforced ring cylinder is discretized into a point cloud P. s ={P1,P2,P3…P n} Calculate the motion trajectory of all points in the point cloud according to the established motion trajectory equation, and draw the trajectory curves of all points undergoing axial anti-envelope motion, thus forming a family of curves C of axial anti-envelope motion trajectories. s ={C1,C2,C3…C n The inner contour line enclosed by the family of curves is the contour line of the transverse rib cavity of the envelope mold 1. Based on the inner contour line of the transverse rib cavity of the envelope mold 1, the transverse rib cavity is machined on the loading area of ​​the envelope mold 1 to ensure that the envelope mold 1 does not interfere with the transverse ribs of the thin-walled high-rib ring cylinder 6.

[0071] S52, referring to the axial reverse envelopment design method of S51, obtain the inner contour line of the longitudinal rib cavity of the envelope mold 1. Based on the inner contour line of the longitudinal rib cavity of the envelope mold 1, the longitudinal rib cavity is machined on the surface of the loading area of ​​the envelope mold 1 to ensure that the envelope mold 1 does not interfere with the longitudinal ribs of the thin-walled high-rib ring cylinder 6.

[0072] S6, Design of the motion of the enveloping die 1: During the multi-degree-of-freedom enveloping forming process of the thin-walled mesh-reinforced ring cylinder 6, the enveloping die 1 first rolls upward along the axial direction to the upper limit position of the loading area of ​​the thin-walled mesh-reinforced ring cylinder 6, then rolls downward along the axial direction to the lower limit position of the loading area of ​​the thin-walled mesh-reinforced ring cylinder 6, and then rolls upward along the axial direction to the middle of the loading area of ​​the thin-walled mesh-reinforced ring cylinder 6. The above process is exactly one axial rolling cycle of the enveloping die 1. One rotation of the constraint die 4 is exactly one enveloping forming pass. At the end of each enveloping forming pass, the enveloping die 1 will return to its initial position. In order to ensure the surface quality of the thin-walled mesh-reinforced ring cylinder 6, the rolling direction of the enveloping die 1 needs to be changed between adjacent enveloping forming passes. In order to maintain a pure rolling motion relationship between the enveloping die 1 and the inner wall of the ring blank 3, the rotational speed w1 of the constraint die 4 and the rotational speed w2 of the enveloping die 1 satisfy the following relationship:

[0073]

[0074] Where r1 is the inner radius of the ring blank 1, and r2 is the maximum radius of the loading area of ​​the envelope mold 1.

[0075] Meanwhile, the angular velocity w3 of the envelope mold 1 about the center of the arc generatrix that contacts the annular blank 3 and its moving velocity v2 along the axial direction of the constraint mold 4 satisfy the following relationship:

[0076] v2=w3R (2)

[0077] Where R is the radius corresponding to the arc generatrix of the loading region of envelope module 1.

[0078] To ensure that the envelope mold 1 returns to its initial position at the end of each envelope forming pass, the following kinematic relationship should be satisfied between the envelope mold 1 and the constraint mold 4:

[0079]

[0080] Where L is half the distance from the upper limit point to the lower limit point of the loading zone of the thin-walled high-ribbed ring cylinder 6.

[0081] S7, Design of Annular Baffles 2 and 5: The outer radius of annular baffles 2 and 5 is equal to the outer radius of constraint mold 4, and the inner radius of annular baffles 2 and 5 is smaller than the inner radius of the web of thin-walled mesh reinforcement ring cylinder 6. The difference between the inner radius of the web of thin-walled mesh reinforcement ring cylinder 6 and the inner radius of annular baffles 2 and 5 is greater than the target rib height of thin-walled mesh reinforcement ring cylinder 6, and the difference between the inner radius of the web of thin-walled mesh reinforcement ring cylinder 6 and the inner radius of annular baffles 2 and 5 is less than the single-sided distance between the outer contours of the clamping area and the loading area of ​​the enveloping mold 1. When designing the axial height of annular baffles 2 and 5, it is necessary to ensure that the axial baffles 2 and 5 will not break during the multi-degree-of-freedom enveloping forming process of thin-walled mesh reinforcement ring cylinder 6.

[0082] To analyze the effect of multi-degree-of-freedom envelope forming of thin-walled mesh-reinforced ring cylinders, a finite element simulation of the multi-degree-of-freedom envelope forming process of thin-walled mesh-reinforced ring cylinder 6 was performed using DEFORM-3D finite element software. The ring blank material was 2219 aluminum alloy, the ring blank forming temperature was 460℃, the rotational speed of constraint mold 4 was 6.28 rad / s, the feed speed of constraint mold 4 was 0.5 mm / s, the total radial feed of constraint mold 4 was 4.2 mm, and the rotational speed of envelope mold 1 was 12.56 rad / s. The oscillation angular velocity setting of envelope mold 1 and the moving speed setting of envelope mold 1 along the axial direction of constraint mold 4 were respectively as follows. Figure 9 As shown in (a) and (b).

[0083] The overall contour changes during the multi-degree-of-freedom envelope forming process of the thin-walled mesh-reinforced ring cylinder are as follows: Figure 10As shown, at the end of the multi-degree-of-freedom envelope forming of the thin-walled mesh-reinforced ring cylinder 6, the heights of both the transverse and longitudinal ribs are close to 25mm. This is because during the multi-degree-of-freedom envelope forming process of the thin-walled mesh-reinforced ring cylinder 6, due to the multi-degree-of-freedom motion of the envelope mold 1, the envelope mold 1 can simultaneously roll along the circumference and axial direction of the ring blank 3, causing the metal inside the ring blank 3 to flow simultaneously along the circumference and axial direction. This metal flow mode is beneficial to the growth of the transverse and longitudinal ribs. The variation law of the radial load of the envelope mold 1 during the multi-degree-of-freedom envelope forming process of the thin-walled mesh-reinforced ring cylinder 6 is as follows: Figure 11 As shown in the figure, the maximum radial load of the envelope mold 1 is less than 60 tons. This is because during the multi-degree-of-freedom envelope forming process of the thin-walled mesh-ribbed ring cylinder 6, the generatrix of the outer contour of the loading area of ​​the envelope mold 1 is an arc, which is in almost point contact with the generatrix of the loading area of ​​the ring blank 3, resulting in a small contact area between the envelope mold 1 and the inner circumferential surface of the ring blank 3, thus causing a small radial load on the envelope mold 1.

[0084] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for controlling the growth and forming load of thin-walled, highly ribbed ring cylinders, characterized in that, The forming device includes a constraint mold, an annular baffle, and an envelope mold. The constraint mold consists of two semi-circular rings, with the inner radius of the constraint mold equal to the outer radius of the ring blank, and the axial height of the constraint mold equal to the axial height of the ring blank. The envelope mold includes a gourd-shaped loading area and two cylindrical clamping areas. The outer surface of the loading area is provided with a cavity for forming high ribs. The two clamping areas are located at both ends of the loading area and connected to the drive mechanism of the envelope forming device. The two clamping areas are coaxial with the loading area. The generatrix of the outer contour of the loading area is arc-shaped, and the length of the generatrix of the outer contour of the loading area is equal to the axial length of the loading area of ​​the thin-walled high-rib ring cylinder. The single-sided distance between the clamping area of ​​the envelope mold and the outer contours at both ends of the loading area is greater than the target rib height of the thin-walled high-rib ring cylinder. The forming method includes the following steps: The ring blank is inserted into the constraint mold, ensuring it fits against the inner circumferential surface of the mold and maintaining a constant outer diameter. Two annular baffles are fixed to both ends of the constraint mold, coaxial with it, ensuring a constant height. An envelope mold is installed inside the constraint mold, fitting against the inner circumferential surface of the ring blank, with its axis parallel to the constraint mold axis. The constraint mold moves the ring blank and the two annular baffles... w A rotational speed of 1 rotates around its own axis, enveloping the model in multi-degree-of-freedom motion: with v Feed the ring blank radially at a speed of 1. w The rotational speed of 2 is about its own axis, while simultaneously rolling back and forth in a plane passing through the axis of the envelope mold and the axis of the constraint mold. This back-and-forth rolling can be decomposed into... w The angular velocity of 3 rotates around the center of the arc generatrix where the envelope mold contacts the annular blank, and at a speed of 3 v 2. The speed moves in translational motion along the axis of the constraint mold; under the combined action of the constraint mold, the envelope mold and the two annular baffles, the envelope mold and the ring blank form an envelope geometric motion relationship in both the circumferential and axial directions, causing the ring blank to undergo continuous local plastic deformation until the high ribs on the inner circumferential surface of the ring blank are completely enveloped and formed by the envelope mold. The method for designing the loading region cavity of the envelope mold includes the following steps: The transverse rib cavity of the envelope mold is designed based on the axial reverse envelope principle of a thin-walled, high-ribbed annular cylinder. Taking the contact position between the envelope mold and the middle of the inner wall of the annular blank as a reference, and with the center of the arc generatrix contacting the inner wall of the annular blank as the origin O, a rectangular coordinate system S0 is established. z The axis is parallel to the axis of the constraint module, and this rectangular coordinate system... x The axis lies in the plane passing through the envelope mold axis and the constraint mold axis; along x A cross-section without longitudinal reinforcement is cut from the thin-walled, highly ribbed annular cylinder, and an arbitrary point is selected on the inner contour line of this cross-section. P 1( x 1, z 1) Make the point P 1. First move downwards along the axis L It reaches the upper limit of the loading zone of the thin-walled, high-ribbed annular cylinder, and simultaneously swings clockwise around the center of the arc generatrix that contacts the inner wall of the annular billet. θ / 2, L and θ The following relationship exists between them: in, L It is half the axial length of the loading zone of the thin-walled, highly reinforced annular cylinder. θ The angle by which the envelope mold swings from the upper limit position of the loading zone of the thin-walled, high-ribbed annular cylinder to its lower limit position; In the rectangular coordinate system S0, point P 1. Speed v 2 along z Towards the Movement t Time, this point in time P 1. Move to point P 2. The rectangular coordinate system S0 is moved to S1, and the origin O is moved to point O'; simultaneously, within the rectangular coordinate system S1, point... P 2 with angular velocity - w 3. Rotate around point O' t At any moment, make a point P 2. Movement to point P 3( x 3, z 3) During the process of the envelope mold moving from the middle position of the loading zone of the thin-walled high-ribbed annular cylinder to its lower limit position, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is: in, x 1 represents any point on the inner contour line of the above-mentioned axial section within the coordinate system S0. x To coordinate values, z 1 represents any point on the inner contour line of the above-mentioned axial section within the coordinate system S0. z To coordinate values, x 3 is in t At any given moment, any point on the inner contour line of the aforementioned axial section lies within the coordinate system S0. x To coordinate values, z 3 is in t At any given moment, any point on the inner contour line of the aforementioned axial section lies within the coordinate system S0. z To coordinate values; During the process of the envelope mold moving from the lower limit position to the upper limit position of the loading zone of the thin-walled, high-ribbed annular cylinder, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is: During the process of the envelope mold moving from the upper limit position of the loading zone of the thin-walled, high-ribbed annular cylinder to its middle position, the motion trajectory equation of any point on the inner contour line of the axial section in coordinate system S0 is:

2. The method for controlling the growth and forming load of thin-walled, highly ribbed ring cylinders according to claim 1, characterized in that, Discretize the inner contour line of the axial section of the thin-walled, high-ribbed ring cylinder into a point cloud. P s ={ P 1, P 2, P 3… P n } Calculate the motion trajectory of all points in the point cloud according to the established motion trajectory equation, and draw the trajectory curves of all points undergoing axial anti-envelope motion, thus forming a family of curves representing axial anti-envelope motion trajectories. C s ={ C 1, C 2, C 3… C n The inner contour line enclosed by the family of curves is the contour line of the transverse rib cavity of the envelope mold; combined with the inner contour line of the transverse rib cavity of the envelope mold, the transverse rib cavity is machined on the loading area of ​​the envelope mold to ensure that the envelope mold does not interfere with the transverse ribs of the thin-walled high-rib ring cylinder. Obtain the inner contour line of the longitudinal rib cavity of the envelope mold; combine the inner contour line of the longitudinal rib cavity of the envelope mold, and machine the longitudinal rib cavity on the surface of the loading area of ​​the envelope mold to ensure that the envelope mold does not interfere with the longitudinal ribs of the thin-walled high-rib ring cylinder.

3. The method for controlling the growth and forming load of thin-walled, highly ribbed ring cylinders according to claim 1, characterized in that, The method for designing the envelope mode motion is as follows: In the multi-degree-of-freedom envelope forming process of thin-walled high-rib ring cylinder, the envelope die first rolls upward along the axial direction to the upper limit position of the loading area of ​​the thin-walled high-rib ring cylinder, then rolls downward along the axial direction to the lower limit position of the loading area of ​​the thin-walled high-rib ring cylinder, and then rolls upward along the axial direction to the middle of the loading area of ​​the thin-walled high-rib ring cylinder. The above process is exactly one axial rolling cycle of the envelope die; one rotation of the constraint die is exactly one envelope forming pass; in order to ensure the surface quality of the thin-walled high-rib ring cylinder, the rolling direction of the envelope die needs to be changed between adjacent envelope forming passes. To maintain a purely rolling motion relationship between the enveloping die and the inner wall of the ring blank, the rotational speed of the constraint die is... w 1. Rotation speed of the envelope mode w The following relationship exists between 2: in, r 1 represents the inner radius of the ring blank. r 2 represents the maximum radius of the envelope module loading region; Simultaneously, the angular velocity of the envelope mold around the center of the arc generatrix in contact with the annular blank... w 3 and its moving speed along the axial direction of the constraint roller v The following relationship exists between 2: in, R The radius corresponding to the generatrix of the circular arc in the loading region of the envelope module; To ensure that the envelope die returns to its initial position at the end of each envelope forming pass, the following kinematic relationship should be satisfied between the envelope die and the constraint die: in, L It is half the distance from the upper limit point to the lower limit point of the loading zone of the thin-walled, highly reinforced ring cylinder.

4. The method for controlling the growth and forming load of thin-walled, highly ribbed ring cylinders according to claim 1, characterized in that, The outer radius of the annular baffle is equal to the outer radius of the constraint mold, and the inner radius of the annular baffle is smaller than the inner radius of the web of the thin-walled, high-ribbed annular cylinder.

5. The method for controlling the growth and forming load of thin-walled, highly ribbed ring cylinders according to claim 1, characterized in that, The difference between the inner radius of the web of the thin-walled high-ribbed ring cylinder and the inner radius of the annular baffle is greater than the target rib height of the thin-walled high-ribbed ring cylinder. The difference between the inner radius of the web of the thin-walled high-ribbed ring cylinder and the inner radius of the annular baffle is less than the single-sided distance between the two ends of the outer contour of the envelope mold clamping area and the loading area.

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