Hydraulic forming method and device for large-diameter metal sealing ring of aero-engine

Abstract

The invention provides a hydraulic forming method and device for a large-diameter metal sealing ring of an aero-engine. According to the forming method, the action area of the liquid pressure is limited through the round pipe blank, and therefore the mold clamping force and the feeding load needed by forming of the large-diameter sealing ring are greatly reduced. 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 sliding block, a right movable die, a right forming sliding block and a positioning block. The forming die device is simple in structure and convenient to disassemble and assemble, and the large-diameter metal sealing ring can be formed through small loads. The diameter of the large-diameter sealing ring is more than 600mm, and a used forming blank is a round tube blank, so that the sealing structure of a forming die can be simplified, the die locking load can be reduced, the blank can bear higher shaping pressure, and the size precision of a sealing ring part can be improved.

Description

Technical Field

[0001] The invention belongs to the field of hydraulic forming, and more specifically, relates to a method and a 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 basic components in high-temperature and high-pressure sealing environments, and are used in important parts such as the combustion chamber, casing, and gas path of aircraft engines. Their airtightness is directly related to the safety, working efficiency, and service life of aircraft engines. Large-diameter sealing rings refer to metal sealing rings with a diameter of more than 600mm. Compared with sealing rings of general size, 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 diameter of the part exceeds 800mm, its cross-sectional shape is complex, and its size is small, and the wall thickness is ultra-thin (only 0.254mm). Due to the large difference between the cross-sectional size and the diameter, it is difficult to ensure the consistency of the cross-sectional size, which puts higher requirements on the forming process of the sealing ring.

[0003] Hydroforming is one of the main methods for precision forming of sealing rings. During the hydroforming process, the material is supplemented at both ends, the component is less thinned (less than 10%), and the forming force in the radial direction of the sealing ring is balanced. The formed waveform is also more uniform. The forming accuracy is guaranteed by the mold, and the roundness and flatness are good. However, the hydroforming process needs to consider the effective sealing of high-pressure fluids. At present, the hydroforming of sealing rings mainly uses annular blanks. The corresponding hydroforming mold must be designed with a sealing structure to ensure the application of high-pressure fluids, resulting in relatively complex mold structure and assembly process, which is not suitable for the forming and manufacturing of large-diameter metal sealing rings. Summary of the invention

[0004] The present invention provides a method and device for hydraulically forming a large-diameter metal sealing ring for an aircraft engine. 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 action area of ​​the liquid pressure, thereby greatly reducing the clamping force required for the forming of the large-diameter sealing ring. The blank can withstand a greater shaping pressure, which is beneficial to improving the forming quality of the sealing ring parts.

[0005] The specific technical scheme of the present invention is as follows: a method and device for hydraulically forming a large-diameter metal sealing ring for an aircraft engine, wherein the blank used in the forming method is a round tube blank (20) in the shape of a ring-shaped round tube, on which a hydraulic pipe joint (22) is welded, and a high-pressure fluid is passed into the inside of the round tube blank to provide bulging pressure. The round tube blank is placed on a blank constraint groove (25), and part 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 feature 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 target 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, which ensures the stability of the structures of the left blank fixed mold and the right blank fixed mold while achieving a large degree of weight reduction of the mold.

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

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

[0009] The left movable mold (2) and the right movable mold (8) are of substantially the same shape, and are provided with a left movable mold annular positioning groove (11) and a right movable mold annular positioning groove (12) at 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 boss is processed with a left forming slider forming surface (15) and a 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 is installed by matching 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 part (13) and a positioning block hanging part (14), wherein the positioning block hanging part is hung on the left movable mold (2) and the right movable mold (8), and the positioning block positioning part 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 part 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 a 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 fixing mold (3) and the right blank fixing mold (9) are provided with blank fixing 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), and 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) in the axial direction, wherein the outer end faces of the left forming slider and the right forming slider are clearance-matched 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) are axially aligned with the left blank fixed mold (3), the right blank fixed mold (9), 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 in the circumferential direction.

[0018] Furthermore, there is a forming slider baffle plate boss (24) 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 too much toward the non-forming area during the forming process.

[0019] The present invention provides a method for hydraulically forming a large-diameter metal sealing ring of 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 into place until they can no longer move forward, determine the initial positions of the left movable mold and the right movable mold, and then take out 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, the force applied to the upper core mold and the left and right movable molds is maintained to keep them stationary, and the 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 cavity of the forming area to form the required sealing annular surface.

[0023] Furthermore, the initial liquid chamber pressure and high-pressure shaping pressure should be determined in appropriate value ranges according to the performance of the material used for the target sealing ring parts, and the appropriate pressure forming curve should be determined through process tests or finite element simulation. The initial liquid chamber pressure should be greater than the minimum hydraulic pressure required to cause the blank to begin plastic deformation. The high-pressure shaping pressure should be selected at a higher pressure by comprehensively considering the clamping force, etc.

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

[0025] Furthermore, the size of the round tube blank radius needs to be determined in an appropriate range according to the material properties and forming requirements of the target sealing ring part, and the appropriate value is determined through process tests or finite element simulation. Under the condition that the thinning rate of the sealing ring part meets the forming requirements, the smaller the round tube blank radius is, the better, but it cannot be less than the distance of the moving mold closing and feeding.

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

[0027] 1) The present invention uses a round tube blank to perform hydraulic forming 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, which can simplify the sealing structure of the hydraulic forming mold. The forming mold has relatively few parts, a simple structure, and is easy to assemble, which can improve the production efficiency of the sealing ring;

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

[0029] 3) In the sealing ring forming die device of the present invention, the left forming slide block and the right forming slide block are both provided with a forming slide block material baffle plate boss, which can effectively solve the problem that the blank is severely bulged toward the non-forming area during the forming process, resulting in a lack of material in the forming area, and is conducive to reducing the thinning rate of the sealing ring component and improving the forming quality of the sealing ring parts;

[0030] 4) The forming blank used in the present invention is a round tube blank, which is used to reduce the action area of ​​the liquid pressure, thereby greatly reducing the clamping force required for forming 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 topological optimization, 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 It is a schematic diagram of a large diameter metal sealing ring part.

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

[0034] Figure 3a , Figure 3b This is a schematic diagram of the structure when the forming mold device has been assembled but forming has not yet begun.

[0035] Figure 4 for Figure 3a A partial 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 schematic diagram of the structure 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 block; 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 baffle plate boss; 25-blank constraint groove;

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

[0048] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments 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 protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0050] This embodiment provides a method and device for hydraulically forming a large diameter metal sealing ring of an aircraft engine. 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 figure shows a schematic diagram of a large-diameter metal sealing ring part. The sealing ring is an annular part made of GH4169. The diameter of the sealing ring is 888mm, and the cross-section of the sealing ring is W-shaped. The wall thickness of the W-shaped cross-section is 0.254mm, the maximum height is 3mm, the width is 5.2mm, and the inner diameters of the three corners are all 1mm. According to the specific size parameters of the sealing ring, the approximate shape and size parameters of the corresponding hydraulic forming mold are designed.

[0052] Figure 2 The flowchart shown is a 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, take the non-characteristic area of ​​the mold as the design domain, take 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 constraints 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 schematic structural diagram of the optimized left blank fixed mold is shown, and 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 a cross-sectional view of the large diameter metal sealing ring hydraulic forming die after assembly. Figure 3b The figure shows the axial view of the large diameter metal sealing ring hydraulic forming die after assembly in this example. At this time, the die device has been assembled but 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, and are provided with a semicircular blank constraint groove 25 for accommodating the round tube blank on the inner end surface, and the shape of the blank constraint groove is a semicircle with an opening; a central through hole 26 of the blank fixing die is opened along the axial center, and the shape of the through hole is obtained by 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, and the inner end faces are provided with a left movable mold annular positioning groove 11 and a right movable mold annular positioning groove 12, and a cylindrical groove is opened along the axial direction at the center of the end face to ensure that the left movable mold and the right movable mold can slide along the axial feed, and 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, both of which are cylindrical structures. A through hole is opened along the axis at 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 left forming slider forming surface 15 and the right forming slider forming surface 16 are processed at the inner end surface boss;

[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 are respectively processed with positioning boss holes and bosses on the fitting surfaces, and 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 part 13 and a positioning block hanging part 14. The positioning block hanging part is hung on the left movable mold 2 and the right movable mold 8. The positioning block positioning part 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 part is the distance of the left movable mold or the right movable mold for mold closing and feeding.

[0058] Figure 5 The figure shows a partial enlarged schematic diagram of the forming die device at the welding hydraulic pipe joint of the round pipe blank. Figures 4-5 As shown, the blank used by the forming device is a round tube blank 20, which is in the shape of a ring-shaped round tube, and a hydraulic pipe joint 22 is welded on it, through which high-pressure fluid is passed into the inside 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 through hole diameter is larger than the diameter of the hydraulic pipe joint 22 welded on the round tube blank and can allow the high-pressure pipe to pass smoothly.

[0060] Specifically, Figure 4 As shown, the left blank fixing mold 3 is evenly provided with blank fixing mold threaded holes 19 along the circumferential direction, and the right blank fixing mold 9 is evenly provided with the same blank fixing mold threaded holes along the circumferential direction corresponding to the opening positions of the left blank fixing mold, and screws pass through the blank fixing mold threaded holes to fix the left and right blank fixing molds in connection.

[0061] Specifically, Figure 4 As shown, the left movable mold 2 and the right movable mold 8 are evenly provided with movable mold threaded holes 18 along the circumferential direction, and the left forming slider 4 and the right forming slider 7 are evenly provided with corresponding threaded holes corresponding to the opening positions of the left movable mold and the right movable mold along the circumferential direction, and 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 together;

[0062] Specifically, 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 along 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, Figure 4As shown, 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 left blank fixed mold 3, the right blank fixed mold 9, and the cylindrical grooves on the inner end faces of the left movable mold and the right movable mold and the inner end faces of 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, 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.

[0064] In particular, such as Figure 4 As shown, there is a forming slider baffle plate boss 24 below the inner end surface forming area of ​​the left forming slider 4 and the right forming slider 7, which is used to prevent excessive bulging of the blank into the non-forming area during the forming process, thereby improving the quality of the formed sealing ring parts.

[0065] Figure 7 The figure shows a partial enlarged schematic diagram of the mold structure after the forming mold device of this example completes the forming, wherein the left forming slider and the right forming slider have completed the mold closing, and the left forming slider forming surface 15, the right forming slider forming surface 16 and the core mold forming surface 17 together constitute a complete forming area cavity of the target sealing ring part.

[0066] Specifically, the radius of the round tube blank is confirmed by the following method: under the condition that the wall thickness reduction rate of the sealing ring meets the forming requirements, the smaller the radius of the round tube blank is, the better, but it cannot be less than the distance of the left movable mold or the right movable mold for closing and feeding. Finite element simulation is carried out at different round tube blank radii. Through finite element simulation, the radius of the round tube blank with high film pasting accuracy and the wall thickness reduction rate of the sealing ring meeting the requirement of less than 10% is 30mm.

[0067] Specifically, the opening size of the blank constraint groove is confirmed 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 expanded length of the sealing ring cross-section. Finite element simulation is performed under different blank constraint groove opening sizes. The blank constraint groove opening size of 15mm that can obtain high film pasting accuracy and a sealing ring wall thickness thinning rate that meets the requirement of less than 10% is selected through finite element simulation.

[0068] The present invention provides a method and device for hydraulically forming a large-diameter metal sealing ring for an aircraft engine, which can form a round tube blank into Figure 1 The large diameter metal sealing ring part shown in the figure includes four operation steps: assembly, mold feeding, high pressure shaping, and trimming:

[0069] Assembly steps: 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 by screws, the left forming slider 4 and the right forming slider 7 are fixedly connected with the corresponding left movable mold 2 and the right movable mold 8 by 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 cannot move forward, and the position is determined to be the initial position of the left movable mold, and then the positioning block is taken out, and the steps are repeated to confirm the initial position of the right movable mold, and 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 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 interior of the round tube blank through a hydraulic pipe joint to fill the interior 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 slide block and the right forming slide block. Under the action of the initial liquid chamber pressure and the closing feed of the left and right forming area slide blocks, 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 cavity of the forming area 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 may be made to the embodiments of the present invention without departing from the inventive concept of the present invention, all of which fall within the protection scope of the present invention.

Claims

1. A hydroforming device for a large diameter metal sealing ring of an aircraft engine, characterized in that: The forming device comprises: a lower core mold, a left movable mold, a left blank fixed mold, a left forming slide block, a positioning block, an upper core mold, a right forming slide block, 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 surfaces of the left movable mold and the right movable mold are both provided with a left movable mold annular positioning groove and 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 blank fixing mold and the right blank fixing mold are both provided with a blank constraint groove for accommodating the round tube blank, and the shape of the blank constraint groove is 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 outer end surfaces of the left forming slider and the right forming slider are installed in the left movable die annular positioning groove and the right movable die annular positioning groove, and the inner end surface boss is processed with the left forming slider forming surface and the right forming slider forming surface; The positioning block includes a positioning block positioning part and a positioning block hanging part. The positioning block hanging part is hung 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 for mold closing and feeding.

2. The hydroforming device for large diameter metal sealing ring of an aircraft engine according to claim 1, characterized in that: 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.

3. The large diameter metal sealing ring hydraulic forming device for an aircraft engine according to claim 1, characterized in that: Through holes are provided at the edges of the left movable die and the left blank fixed die, and 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 connection can pass smoothly.

4. A hydroforming device for a large diameter metal sealing ring of an aircraft engine according to claim 1 or 3, characterized in that: The left blank fixing mold and the right blank fixing mold are provided with blank fixing mold threaded holes, which 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, which are connected by screws.

5. The hydroforming device for large diameter metal sealing ring of aircraft engine according to claim 1, characterized in that: The left movable mold, the right movable mold, the left forming slider, and the 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-matched with the semi-cylindrical grooves on the inner end faces of the upper core mold and the lower core mold in the circumferential direction.

6. The hydroforming device for large diameter metal sealing ring of 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 in the circumferential direction.

7. The hydroforming device for large diameter metal sealing ring of aircraft engine according to claim 1, characterized in that: There is a forming slider baffle 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.

8. A forming method for realizing the large diameter metal sealing ring hydraulic forming device of aircraft engine according to claim 1, characterized in that: The steps include: 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 into place until they can no longer move forward, determine the initial positions of the left movable mold and the right movable mold, and then take out 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 movable mold and the right movable mold, and the left movable mold and the right movable mold begin to feed material into the middle mold; Step 3: After the left and right movable molds are closed, the force applied to the upper core mold and the left and right movable molds is maintained to keep them stationary, and the 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 cavity of the forming area to form the required sealing annular surface.

9. The forming method according to claim 8, characterized in that: The initial liquid chamber pressure and the high-pressure shaping pressure are used to determine the appropriate pressure forming curve 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.

10. The forming method according to claim 8, characterized in that: The radius of the round tube blank is as small as possible while ensuring that the thinning rate of the sealing ring part meets the forming requirements, but it cannot be smaller than the distance of the left movable mold or the right movable mold for closing and feeding.

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