Hydroforming method and device for large-diameter metal sealing ring of an aero-engine

Abstract

The application provides a hydraulic forming method and device for a large-diameter metal sealing ring of an aero-engine. The forming method utilizes a circular pipe blank to limit the action area of liquid pressure, thereby greatly reducing the locking force and feeding load required for forming the large-diameter sealing ring. The forming device comprises a left blank fixing die, a right blank fixing die, an upper core die, a lower core die, a left movable die, a left forming slider, a right movable die, a right forming slider and a positioning block. The forming die device has a simple structure and is convenient to disassemble and assemble, and can form a large-diameter metal sealing ring by using a smaller load. The diameter of the large-diameter sealing ring is greater than 600 mm, the forming blank used is a circular pipe blank, the sealing structure of the forming die can be simplified, the locking load is reduced, the blank can bear a larger shaping pressure, and the size precision of the sealing ring part is improved.

Description

Technical Field

[0001] The present invention belongs to the field of hydraulic forming, and more specifically, relates to a method and device for hydraulic forming a large-diameter metal sealing ring of an aero-engine. Background Art

[0002] Metal sealing rings are widely used as key components in high-temperature, high-pressure sealing environments, including in combustion chambers, casings, and air paths in aircraft engines. Their airtightness is directly related to the safety, operating efficiency, and service life of aircraft engines. Large-diameter sealing rings are those with a diameter of 600mm or more. Compared to standard-sized sealing rings, they have a larger diameter-to-wall-thickness ratio. Figure 1 This is a schematic diagram of a large-diameter W-shaped sealing ring part and its cross-section. The part's diameter exceeds 800mm, and its cross-sectional shape is complex, its dimensions are tiny, and its wall thickness is ultra-thin (only 0.254mm). Because the cross-sectional dimensions differ significantly from the diameter, ensuring cross-sectional dimensional consistency is difficult, placing higher demands on the sealing ring's forming process.

[0003] Hydroforming is one of the primary methods for precision forming sealing rings. During the hydroforming process, material is added at both ends, resulting in minimal component thinning (less than 10%). Furthermore, the forming force in the radial direction of the sealing ring is balanced, resulting in a relatively uniform wave form. Forming precision is ensured by the mold, with good roundness and flatness. However, the hydroforming process requires effective sealing against high-pressure fluids. Currently, hydroforming of sealing rings primarily uses annular blanks. The corresponding hydroforming molds must be designed with sealing structures to ensure the application of high-pressure fluids. This results in a relatively complex mold structure and assembly process, making it unsuitable for forming large-diameter metal sealing rings. Summary of the Invention

[0004] The present invention provides a method and device for hydraulically forming large-diameter metal sealing rings for aircraft engines. A round tube blank is used in the forming process, which can simplify the sealing structure of the forming mold. The round tube blank is used to limit the area where liquid pressure acts, thereby significantly reducing the clamping force required for forming large-diameter sealing rings. The blank can withstand greater shaping pressure, which is beneficial to improving the forming quality of the sealing ring parts.

[0005] The specific technical solution of the present invention is as follows: a method and apparatus for hydraulically forming a large-diameter metal sealing ring for an aircraft engine, wherein the blank used in the forming method is a circular tube blank (20) in the shape of an annular circular tube, on which a hydraulic pipe joint (22) is welded, through which a high-pressure fluid is introduced into the interior of the circular tube blank to provide bulging pressure. The circular tube blank is placed on a blank constraint groove (25), and a portion of the blank outside the semicircular opening of the blank constraint groove is not constrained and participates in the forming of the sealing ring;

[0006] The forming method adopts a topology optimization method to perform lightweight design on the left blank fixed mold (3) and the right blank fixed mold (9). The specific process of topology optimization is as follows: Figure 2 As shown in the figure, the integrity of the characteristic areas such as the blank constraint groove and screw hole is ensured, the non-feature area of ​​the mold is used as the design domain, the strain energy and volume of the mold components are used as the design response of the topology optimization, the optimization goal is set to minimize the global strain energy of the mold, the stamping manufacturing constraints are set, the volume fraction constraints are continuously adjusted, and the mold is topologically optimized until an optimization result with good manufacturability is obtained. While ensuring the structural stability of the left blank fixed mold and the right blank fixed mold, the mold can achieve a large degree of weight reduction.

[0007] The forming device comprises: a lower core mold (1), a left movable mold (2), a left blank fixed mold (3), a left forming slider (4), a positioning block (5), an upper core mold (6), a right forming slider (7), a right movable mold (8), and a right blank fixed mold (9);

[0008] The left blank fixing die (3) and the right blank fixing die (9) have substantially the same shape, and both are provided with a constraint groove (25) for accommodating a circular tube blank on their inner end faces, the shape of the constraint groove being a semicircle with an opening; a central through hole (26) of the blank fixing die is opened along the axial center, the shape of the through hole being obtained by topological optimization; an additional blank fixing die through hole (21) is opened on the blank constraint groove of the left blank fixing die (3);

[0009] The left movable mold (2) and the right movable mold (8) are of substantially the same shape, and are both provided with a left movable mold annular positioning groove (11) and a right movable mold annular positioning groove (12) on their inner end surfaces, and an additional left movable mold through hole (10) is provided at the edge of the left movable mold;

[0010] The left forming slider (4) and the right forming slider (7) have the same shape, and the outer end faces are installed in the left movable die annular positioning groove (11) and the right movable die annular positioning groove (12), and the inner end face bosses are processed with the left forming slider forming surface (15) and the right forming slider forming surface (16);

[0011] The upper core mold (6) and the lower core mold (1) are of substantially the same shape, and a core mold forming surface (17) is processed at the root, and are mounted through the positioning boss hole of the upper core mold and the positioning boss of the lower core mold;

[0012] The positioning block (5) comprises a positioning block positioning portion (13) and a positioning block hanging portion (14), wherein the positioning block hanging portion is hung on the left movable mold (2) and the right movable mold (8), and the positioning block positioning portion is placed between the upper core mold (6), the lower core mold (1) and the two end surfaces of the left movable mold (2) and the right movable mold (8), and the thickness of the positioning block positioning portion is the distance of the left movable mold or the right movable mold for mold closing and feeding;

[0013] The left forming slider forming surface (15), the right forming slider forming surface (16) and the core mold forming surface (17) together constitute the forming area cavity of the sealing ring part.

[0014] Furthermore, through holes (10, 21) are provided at the edges of the left movable die and the left blank fixed die (3), the diameter of the through holes being larger than the diameter of the hydraulic pipe joint (22) welded on the round tube blank and enabling the high-pressure pipe to pass smoothly.

[0015] Furthermore, the left blank fixed mold (3) and the right blank fixed mold (9) are provided with blank fixed mold threaded holes (19) and are connected by screws, and the left movable mold (2), the right movable mold (8) and the left forming slider (4), the right forming slider (7) are provided with movable mold threaded holes (18) and are connected by screws.

[0016] Furthermore, the left movable mold (2), the right movable mold (8), the left forming slider (4), and the right forming slider (7) are axially aligned with the semi-cylindrical grooves (23) on the inner end faces of the upper core mold (6) and the lower core mold (1), wherein the outer end faces of the left forming slider and the right forming slider are clearance-fitted with the semi-cylindrical grooves on the inner end faces of the upper core mold and the lower core mold in the circumferential direction.

[0017] Furthermore, the left movable mold (2), the right movable mold (8), the left forming slider (4), the right forming slider (7) and the left blank fixed mold (3) and the right blank fixed mold (9) are axially aligned, and the inner end faces of the left movable mold, the right movable mold, the left forming slider and the right forming slider are clearance-matched with the outer end faces of the left blank fixed mold and the right blank fixed mold in the circumferential direction.

[0018] Furthermore, a forming slider block plate boss (24) is provided below the forming area of ​​the inner end surface of the left forming slider (4) and the right forming slider (7), which can prevent the blank from bulging excessively toward the non-forming area during the forming process.

[0019] The present invention provides a method for hydroforming a large-diameter metal sealing ring for an aero-engine, comprising the following steps:

[0020] Step 1: Place the round tube blank on the blank constraint groove, install the left forming slider and the right forming slider on the corresponding left movable mold and right movable mold respectively, hang the positioning blocks on the left movable mold and the right movable mold in turn, push the left movable mold and the right movable mold in until they can no longer move forward, determine the initial positions of the left movable mold and the right movable mold, and then remove the positioning blocks;

[0021] Step 2: Apply clamping force to the upper core mold, introduce hydraulic fluid into the inside of the round tube blank to fill it, establish initial liquid chamber pressure, bulge the round tube blank, apply feed force to the left and right movable molds, and the left and right movable molds begin to feed material into the middle mold.

[0022] Step 3: After the left and right movable molds are closed, maintain the force applied to the upper core mold and the left and right movable molds to keep them stationary, and continue to increase the pressure inside the round tube blank until the high-pressure shaping pressure requirement is reached. Under the action of high pressure, the blank is tightly attached to the forming area cavity to form the required sealing annular surface.

[0023] Furthermore, the initial liquid chamber pressure and high-pressure shaping pressure must be determined within appropriate ranges based on the properties of the target sealing ring material. A suitable pressure forming curve should be determined through process testing or finite element simulation. The initial liquid chamber pressure should be greater than the minimum hydraulic pressure required to initiate plastic deformation of the blank. The high-pressure shaping pressure should be selected at a higher pressure, taking into account factors such as clamping force.

[0024] Furthermore, the size of the blank constraint groove opening needs to be determined based on the material properties and forming requirements of the target sealing ring part through process testing or finite element simulation to ensure that the blank has good fluidity and meets the thinning rate requirements of the sealing ring forming.

[0025] Furthermore, the radius of the round tube blank must be determined within an appropriate range based on the material properties and forming requirements of the target sealing ring component, and the appropriate value should be determined through process testing or finite element simulation. While ensuring that the thinning ratio of the sealing ring component meets the forming requirements, the radius of the round tube blank should be as small as possible, but it should not be smaller than the distance required for the movable mold to close and feed the material.

[0026] The beneficial effects of the present invention are:

[0027] 1) The present invention uses a round tube blank for hydroforming of a metal sealing ring. During the forming process, only the sealing of the welded hydraulic pipe joint on the round tube blank needs to be considered. This simplifies the sealing structure of the hydroforming mold. The forming mold has relatively few parts, a simple structure, and is easy to assemble, thereby improving the production efficiency of the sealing ring.

[0028] 2) In the large-diameter sealing ring hydraulic forming die assembly of the present invention, the die components constituting the forming area cavity are of an insert structure, which is convenient and quick to disassemble and replace. The corresponding slider components can be replaced according to the target sealing ring shape, which improves the die utilization rate and effectively reduces the production cost of the die assembly;

[0029] 3) In the sealing ring forming die device of the present invention, both the left and right forming slides are provided with forming slide block plate bosses, which can effectively solve the problem of severe bulging of the blank toward the non-forming area during the forming process, resulting in material shortage in the forming area. This helps to reduce the thinning rate of the sealing ring component and improve the forming quality of the sealing ring part.

[0030] 4) The forming blank used in the present invention is a round tube blank. The round tube blank is used to reduce the area where the liquid pressure acts, thereby significantly reducing the clamping force required to form a large-diameter sealing ring, and can form a metal sealing ring with a smaller load;

[0031] 5) Some mold components of the present invention are lightweighted by using a topology optimization method, which can effectively reduce the weight of the mold while ensuring the structural strength of the mold, making it easier to install the mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a large-diameter metal sealing ring part.

[0033] Figure 2 Flowchart for lightweight design of blank fixed mold using topology optimization method.

[0034] Figure 3a 、 Figure 3b This is a structural diagram of the forming mold device after assembly is completed and forming has not yet begun.

[0035] Figure 4 for Figure 3a A partially enlarged schematic diagram of the forming area of ​​the forming mold device.

[0036] Figure 5 It is a partially enlarged schematic diagram of the forming die installed at the hydraulic pipe joint of the round pipe blank.

[0037] Figure 6 It is a structural diagram of the left blank fixed mold.

[0038] Figure 7 It is a partial enlarged schematic diagram of the forming area after the forming mold device completes the mold closing.

[0039] The numbers in the figure are explained as follows:

[0040] 1-lower core mold; 2-left movable mold; 3-left blank fixed mold; 4-left forming slide; 5-positioning block;

[0041] 6-upper core mold; 7-right forming slider; 8-right movable mold; 9-right blank fixed mold; 10-left movable mold through hole;

[0042] 11- annular positioning groove of the left movable mold; 12- annular positioning groove of the right movable mold; 13- positioning part of the positioning block;

[0043] 14-positioning block hanging part; 15-left forming slider forming surface; 16-right forming slider forming surface;

[0044] 17- forming surface of core mold; 18- threaded hole of movable mold; 19- threaded hole of blank fixed mold;

[0045] 20-round tube blank; 21-blank fixed die through hole; 22-hydraulic pipe joint;

[0046] 23-semi-cylindrical groove on the inner end face of the core mold; 24-forming slider block plate boss; 25-blank constraint groove;

[0047] 26-Central through hole of blank fixing mold. DETAILED DESCRIPTION

[0048] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features therein can be combined with each other without conflict.

[0049] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0050] This embodiment provides a method and device for hydroforming a large diameter metal sealing ring of an aircraft engine, such as Figures 1 to 7 As shown, the blank used in the forming process is a round tube blank, and the forming device includes: a lower core mold 1, a left movable mold 2, a left blank fixed mold 3, a left forming slider 4, a positioning block 5, an upper core mold 6, a right forming slider 7, a right movable mold 8, a right blank fixed mold 9, etc.;

[0051] Figure 1 The diagram below shows a large-diameter metal sealing ring. This ring is annular and made of GH4169. The ring has a diameter of 888mm and a W-shaped cross-section with a wall thickness of 0.254mm, a maximum height of 3mm, a width of 5.2mm, and an inner diameter of 1mm at each of the three corners. The general shape and dimensions of the hydroforming die were designed based on the specific dimensional parameters of the sealing ring.

[0052] Figure 2 The figure shows a flow chart of lightweight design of the left blank fixed mold and the right blank fixed mold using the topology optimization method. The topology optimization method is used to lightweight and reduce the weight of the preliminarily designed left blank fixed mold and the right blank fixed mold. The specific process is to ensure the integrity of the characteristic areas such as the blank constraint groove and the screw hole, use the non-characteristic area of ​​the mold as the design domain, use the strain energy and volume of the mold parts as the design response of the topology optimization, set the optimization target to minimize the global strain energy of the mold, set the volume fraction constraint, perform topology optimization on the mold, and continuously adjust the constraint to ensure the structural stability of the left blank fixed mold and the right blank fixed mold while achieving a large degree of weight reduction of the mold. Finally, when the volume fraction constraint is 45%, it is obtained Figure 6 The structural schematic diagram of the optimized left blank fixed mold is shown in the figure. The optimized shape of the design domain of the right blank fixed mold is the same as that of the left blank fixed mold.

[0053] Figure 3a The figure shows the cross-sectional view of the large diameter metal sealing ring hydraulic forming die after assembly. Figure 3b The figure shows an axial view of the large diameter metal sealing ring hydraulic forming die after assembly. At this time, the die assembly is completed and forming has not yet begun. Figure 6 Shown is a schematic structural diagram of the left blank fixed mold. Figure 3a 、 Figure 6 The left blank fixing die 3 and the right blank fixing die 9 are roughly the same in shape, both of which are cylindrical structures. A semicircular blank constraint groove 25 is provided on the inner end surface for accommodating the round tube blank. The blank constraint groove is in the shape of a semicircle with an opening. A central through hole 26 of the blank fixing die is opened along the axial center. The shape of the through hole is obtained through topological optimization. An additional through hole 21 is opened on the blank constraint groove of the left blank fixing die.

[0054] Figure 4 Shown Figure 3a A partial enlarged view of Figure 3a 、 Figure 3b 、 Figure 4 As shown, the left movable mold 2 and the right movable mold 8 are roughly the same in shape, both of which are cylindrical structures. The inner end surfaces of the left movable mold are provided with a left movable mold annular positioning groove 11 and a right movable mold annular positioning groove 12. A cylindrical groove is opened along the axial direction in the center of the end surface to ensure that the left movable mold and the right movable mold can slide along the axial feed. An additional left movable mold through hole 10 is opened at the edge of the left movable mold;

[0055] Figure 3a 、 Figure 4 The left forming slider 4 and the right forming slider 7 have the same shape and are both cylindrical structures. A through hole is opened along the axis in the center of the end surface, which can allow the left blank fixed mold and the right blank fixed mold to pass smoothly, ensuring that the left forming slider and the right forming slider can slide along the axial feed. The outer end surface is installed on the left movable mold annular positioning groove 11 and the right movable mold annular positioning groove 12, and the inner end surface boss is processed with the left forming slider forming surface 15 and the right forming slider forming surface 16;

[0056] Figure 3a 、 Figure 4 The upper core mold 6 and the lower core mold 1 are roughly the same in shape, and the root is processed with a core mold forming surface 17. The upper core mold and the lower core mold fitting surface are respectively processed with positioning boss holes and bosses, which are installed through the positioning boss holes of the upper core mold and the positioning bosses of the lower core mold;

[0057] Figure 3a 、 Figure 4The middle positioning block 5 includes a positioning block positioning portion 13 and a positioning block hanging portion 14. The positioning block hanging portion is suspended on the left movable mold 2 and the right movable mold 8. The positioning block positioning portion is placed between the lower core mold 1, the upper core mold 6 and the two end surfaces of the left movable mold 2 and the right movable mold 8. The thickness of the positioning block positioning portion is the distance of the left movable mold or the right movable mold clamping feed;

[0058] Figure 5 The figure shows a partial enlarged schematic diagram of the forming die device at the hydraulic pipe joint where the round pipe blank is welded. Figures 4-5 As shown, the blank used in the forming device is a round tube blank 20, which is in the shape of a ring-shaped circular tube and has a hydraulic pipe joint 22 welded thereon, through which high-pressure fluid is passed into the interior of the round tube blank to provide bulging pressure;

[0059] In particular, such as Figure 3b 、 Figure 5 As shown, through holes 10 and 21 are opened at the edge positions of the left movable mold and the left blank fixed mold. The through holes are axially aligned with the hydraulic pipe joints welded on the round tube blank. The diameter of the through holes is larger than the diameter of the hydraulic pipe joints 22 welded on the round tube blank, and can allow the high-pressure pipe to pass through smoothly.

[0060] Specifically, such as Figure 4 As shown, the left blank fixing mold 3 has blank fixing mold threaded holes 19 evenly distributed along the circumferential direction, and the right blank fixing mold 9 has the same blank fixing mold threaded holes evenly distributed along the circumferential direction corresponding to the left blank fixing mold opening positions, and screws pass through the blank fixing mold threaded holes to fix the left and right blank fixing molds together.

[0061] Specifically, such as Figure 4 As shown, the left movable mold 2 and the right movable mold 8 are evenly distributed with movable mold threaded holes 18 along the circumferential direction, and the left forming slider 4 and the right forming slider 7 are evenly distributed with corresponding threaded holes along the circumferential direction corresponding to the opening positions of the left movable mold and the right movable mold. Screws pass through the movable mold threaded holes to fix the left movable mold, the right movable mold and the corresponding left forming slider and the right forming slider;

[0062] Specifically, such as Figure 4 As shown, a semi-cylindrical groove 23 is opened on the inner side of the upper and lower core molds along the axial direction. The left movable mold 2, the right movable mold 8 and the left forming slider 4, the right forming slider 7 are axially aligned with the semi-cylindrical groove 23 of the inner end surface of the core mold of the upper core mold 6 and the lower core mold 1 in the axial direction, wherein the outer end surfaces of the left forming slider and the right forming slider and the semi-cylindrical groove of the inner end surface of the core mold of the upper core mold and the lower core mold are clearance-matched in the circumferential direction, ensuring that the left movable mold, the right movable mold and the left forming slider and the right forming slider can slide along the axial feed.

[0063] Specifically, such as Figure 4As shown, the left movable die 2, the right movable die 8 and the left forming slider 4, the right forming slider 7 are axially centered with the left blank fixing die 3, the right blank fixing die 9, and the inner end face cylindrical groove of the left movable die, the right movable die and the inner end face of the left forming slider, the right forming slider are clearance fitted with the outer end face of the left blank fixing die, the right blank fixing die in the circumferential direction, so as to ensure that the left movable die, the right movable die and the left forming slider, the right forming slider can slide along the axial feeding.

[0064] In particular, as Figure 4 As shown, the inner end face forming area of the left forming slider 4, the right forming slider 7 is provided with a forming slider material blocking plate boss 24 below, which is used for preventing the excessive expansion of the blank to the non-forming area during the forming process, and improving the quality of the formed sealing ring part.

[0065] Figure 7 As shown in the partial enlarged view of the mold structure after the forming of the mold device of the present example, the left forming slider and the right forming slider have completed the clamping, and the left forming slider forming surface 15, the right forming slider forming surface 16 and the core mold forming surface 17 together constitute the complete forming area cavity of the target sealing ring part.

[0066] Specifically, the radius of the circular tube blank is determined by the following method: in the case of ensuring that the sealing ring wall thickness reduction rate meets the forming requirements, the smaller the radius of the circular tube blank is, the better, but it cannot be smaller than the distance of the left movable die or the right movable die clamping feeding, finite element simulation is carried out under different circular tube blank radii, and the circular tube blank radius of 30mm is selected through finite element simulation, which can obtain high film adhesion precision and meet the requirement that the sealing ring wall thickness reduction rate is less than 10%.

[0067] Specifically, the opening size of the blank constraint groove is determined by the following method: the opening size of the blank constraint groove cannot be larger than the radius of the circular tube blank, and cannot be smaller than half of the developed length of the sealing ring cross section, finite element simulation is carried out under different opening sizes of the blank constraint groove, and the opening size of 15mm of the blank constraint groove is selected through finite element simulation, which can obtain high film adhesion precision and meet the requirement that the sealing ring wall thickness reduction rate is less than 10%.

[0068] The present application provides a hydraulic forming method and device for large-diameter metal sealing ring of an aero-engine, which can form a circular tube blank into Figure 1 As shown in the large-diameter metal sealing ring part, the specific embodiment includes four operation steps of assembly, clamping feeding, high-pressure shaping and edge cutting:

[0069] Assembly step: as Figure 3a , Figure 3b , Figure 4As shown, the round tube blank 20 is placed on the blank constraint groove 25 of the left blank fixed mold 3, the left blank fixed mold 3 and the right blank fixed mold 9 are connected with screws, the left forming slider 4 and the right forming slider 7 are fixedly connected with the corresponding left movable mold 2 and right movable mold 8 with screws, the lower core mold 1 is placed in the specified position of the external hydraulic device, the upper core mold 6 is connected to the lower core mold 1, the left movable mold connected with the left forming slider is placed on the lower core mold, the assembled left blank fixed mold and the right blank fixed mold are placed on the left movable mold, the right movable mold is placed on the lower core mold, the positioning block 5 is hung on the left movable mold, and the left movable mold is pushed in until it can no longer move forward, and this position is determined to be the initial position of the left movable mold, then the positioning block is taken out, and this step is repeated to confirm the initial position of the right movable mold, then the positioning block is taken out, and the external hydraulic pipe is connected to the hydraulic pipe joint of the round tube blank, and the assembly preparation is completed;

[0070] Mould closing and feeding steps: Figure 3a 、 Figure 3b 、 Figure 4 As shown, a clamping force is applied to the upper core mold through an external hydraulic device, and hydraulic fluid is introduced into the inside of the round tube blank through a hydraulic pipe joint to fill the inside of the round tube blank, establish an initial liquid chamber pressure, and bulge the round tube blank. A feed force is applied to the left movable mold and the right movable mold through an external hydraulic device, and the left movable mold and the right movable mold start to close the mold together with the corresponding left forming slider and the right forming slider. Under the action of the initial liquid chamber pressure and the closing feed of the left and right forming area sliders, the blank gradually expands toward the forming area cavity to form the approximate shape of the sealing ring.

[0071] High pressure shaping steps: Figure 7 As shown in the figure, after the left and right movable molds are closed, the pressure applied to the upper core mold and the left and right movable molds is maintained to keep the mold components stationary, and the hydraulic pressure inside the round tube blank is continued to increase until the high-pressure shaping pressure requirement is reached. Under the action of high pressure, the blank is tightly attached to the forming area cavity to form the target sealing annular surface.

[0072] Trimming steps: After forming is completed, remove the external hydraulic pipe, remove the right movable mold and the right forming slider connected to it, remove the right blank fixed mold and the round tube blank and left blank fixed mold connected to it, remove the screws fixing the left blank fixed mold and the right blank fixed mold, take out the formed sealing ring parts, and then use the trimming device to cut off the excess blank to obtain the target large-diameter sealing ring.

[0073] For those skilled in the art, several modifications and improvements can be made to the embodiments of the present invention without departing from the inventive concept of the present invention, and all of these modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A hydroforming device for large-diameter metal sealing rings for aircraft engines, characterized by: The forming device comprises: a lower core mold, a left movable mold, a left blank fixed mold, a left forming slider, a positioning block, an upper core mold, a right forming slider, a right movable mold and a right blank fixed mold; The roots of the upper core mold and the lower core mold are processed with core mold forming surfaces, which are installed through the positioning boss holes of the upper core mold and the positioning bosses of the lower core mold; The inner end surface of the left movable mold is provided with a left movable mold annular positioning groove, the inner end surface of the right movable mold is provided with a right movable mold annular positioning groove, and an additional left movable mold through hole is opened at the edge of the left movable mold; The inner end surfaces of the left and right blank fixing molds are both provided with blank constraint grooves for accommodating the circular tube blank. The circular tube blank is in the shape of an annular circular tube, and the blank constraint groove is in the shape of a semicircle with an opening. A central through hole of the blank fixing mold is opened along the axial center, and the shape of the through hole is obtained by topological optimization. An additional blank fixing mold through hole is opened on the blank constraint groove of the left blank fixing mold. The left forming slider and the right forming slider have the same shape and are both cylindrical structures. A through hole is opened along the axis at the center of the end surface to allow the left blank fixed mold and the right blank fixed mold to pass smoothly, ensuring that the left forming slider and the right forming slider slide along the axial feed. The outer end surface of the left forming slider is installed on the annular positioning groove of the left movable mold, and the outer end surface of the right forming slider is installed on the annular positioning groove of the right movable mold. The left forming slider forming surface and the right forming slider forming surface are processed at the inner end surface boss. The positioning block includes a positioning block positioning part and a positioning block hanging part. The positioning block hanging part is suspended on the left movable mold and the right movable mold. The positioning block positioning part is placed between the upper core mold, the lower core mold and the two end surfaces of the left movable mold and the right movable mold. The thickness of the positioning block positioning part is the distance of the left movable mold or the right movable mold clamping feed; The left forming slider forming surface, the right forming slider forming surface and the core mold forming surface together constitute the forming area cavity of the sealing ring.

2. The hydroforming device for a large-diameter metal sealing ring for an aircraft engine according to claim 1, characterized in that: Through holes are opened at the edges of the left movable die and the left blank fixed die. The diameter of the through holes is larger than the diameter of the hydraulic pipe joint welded on the round tube blank, so that the high-pressure pipe can pass through smoothly.

3. The hydroforming device for a large-diameter metal sealing ring for an aircraft engine according to claim 1 or 2, characterized in that: The left blank fixed mold and the right blank fixed mold are provided with blank fixed mold threaded holes and are connected by screws; the left movable mold, the right movable mold and the left forming slide block and the right forming slide block are provided with movable mold threaded holes and are connected by screws.

4. The hydroforming device for a large-diameter metal sealing ring for an aircraft engine according to claim 1, characterized in that: The left movable mold, right movable mold, left forming slider and right forming slider are axially aligned with the semi-cylindrical grooves on the inner end faces of the upper core mold and the lower core mold in the axial direction, wherein the outer end faces of the left forming slider and the right forming slider are clearance-fitted with the semi-cylindrical grooves on the inner end faces of the upper core mold and the lower core mold in the circumferential direction.

5. The hydroforming device for a large-diameter metal sealing ring for an aircraft engine according to claim 1, characterized in that: The left movable mold, the right movable mold, the left forming slider, the right forming slider are axially aligned with the left blank fixed mold and the right blank fixed mold, and the inner end surfaces of the left movable mold, the right movable mold, the left forming slider, and the right forming slider are clearance-matched with the outer end surfaces of the left blank fixed mold and the right blank fixed mold along the circumferential direction.

6. The hydroforming device for a large-diameter metal sealing ring for an aircraft engine according to claim 1, characterized in that: There is a forming slider block plate boss below the forming area of ​​the inner end surface of the left forming slider and the right forming slider, which reduces the degree of bulging of the blank toward the non-forming area during the forming process.

7. A forming method for a large-diameter metal sealing ring of an aircraft engine based on the hydroforming device of claim 1, characterized in that: The steps are as follows: Step 1: Place the round tube blank on the blank constraint groove, install the left forming slider and the right forming slider on the corresponding left movable mold and right movable mold respectively, hang the positioning blocks on the left movable mold and the right movable mold in turn, push the left movable mold and the right movable mold in until they can no longer move forward, determine the initial positions of the left movable mold and the right movable mold, and then remove the positioning blocks; Step 2: Apply clamping force to the upper core mold, introduce hydraulic fluid into the inside of the round tube blank to fill it, establish initial liquid chamber pressure, bulge the round tube blank, apply feed force to the left and right movable molds, and the left and right movable molds begin to feed material into the middle mold; Step 3: After the left and right movable molds are closed, maintain the force applied to the upper core mold and the left and right movable molds to keep them stationary, and continue to increase the pressure inside the round tube blank until the high-pressure shaping pressure requirement is reached. Under the action of high pressure, the blank is tightly attached to the forming area cavity to form the required sealing annular surface.

8. The forming method according to claim 7, wherein: The initial liquid chamber pressure and high-pressure shaping pressure are used to determine appropriate pressure forming curves through process tests or finite element simulations; the initial liquid chamber pressure should be greater than the minimum hydraulic pressure required to cause the blank to begin plastic deformation.

9. The forming method according to claim 7, wherein: The radius of the round tube blank should be as small as possible while ensuring that the thinning rate of the sealing ring part meets the forming requirements, but it should not be smaller than the distance between the left movable mold and the right movable mold for closing and feeding.

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