A method and device for integrally forming a titanium alloy casing of an aero-engine

Abstract

The application discloses an aero-engine titanium alloy shell integral forming method and device, and the forming method comprises the following steps of blanking, hot stretching forming, machining shape and pickling in sequence. The plate material with the same wall thickness as the final titanium alloy shell is cut into a circular ring-shaped rough material in the blanking. The cylindrical surface, two taper surfaces and two transition fillets are completed at one time in the hot stretching forming. The hot stretching die adopted by the application comprises a concave die, a convex die, a top plate, a pull rod and a beating plate, and the beating plate can rotate around the pull rod. The forming method adopted by the application can improve the processing efficiency, shorten the processing period and avoid the wrinkle problem at the transition fillets.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy hot forming technology, specifically a method and apparatus for integral forming of titanium alloy shell for aero-engines. Background Technology

[0002] The aircraft engine casing is made of TC1 material with a thickness of t = 1 mm. The part is a titanium alloy rotating structure, consisting of two conical surfaces and one cylindrical surface. The small end diameter is D3, the large end diameter is D1, and the middle cylindrical surface is D2. The two conical surfaces form angles A and B with the part's axis, respectively. The transition radii between the two conical surfaces and the cylindrical surface are R1 and R2, respectively. Specific dimensions are as follows... Figure 1 As shown.

[0003] Currently, the shell is processed using a process of split thermoforming → welding → hot straightening. The parts have two longitudinal weld seams. During the split thermoforming process, wrinkles are easily formed near the corners of the parts. Furthermore, during welding, the welding process is difficult due to the welding of the parts with attached profiles, making ventilation and protection difficult. After the parts are welded into a cylinder, they are hot straightened. Each part requires two thermoforming processes in total, resulting in long processing time and low processing efficiency. Summary of the Invention

[0004] The present invention aims to provide a method and apparatus for integral forming of titanium alloy housing for aero-engines, which shortens processing time, improves processing efficiency, and avoids wrinkling problems near the transition fillets of titanium alloy housings.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An integral forming device for aero-engine titanium alloy casing, comprising:

[0007] Download template;

[0008] Upper template, wherein a through groove is formed on the upper template;

[0009] The punch includes a convex surface for forming the inner surface of the titanium alloy shell. The punch is fixed to the upper end face of the lower template and has a first through hole coaxial with the punch.

[0010] The die includes a concave surface for forming the outer surface of the titanium alloy shell. The die is fixed to the lower end face of the upper template. The bottom of the concave surface of the die has a second through hole that communicates with the through groove of the upper template.

[0011] A top plate, wherein the top plate is an annular component, and the punch is placed in the inner annular surface of the top plate;

[0012] A pull rod is placed in the first through hole of the punch. The upper end of the pull rod extends from the opening of the first through hole away from the lower template and extends at least into the second through hole. A groove is opened on the upper end face of the pull rod, and the groove extends along the axial direction of the pull rod. A limiting structure is provided at the lower end of the pull rod to prevent the pull rod from disengaging from the first through hole.

[0013] The striking plate is rotatably connected to the slot on the upper end face of the pull rod. The length of the striking plate is greater than the diameter of the first through hole on the punch, the width of the striking plate is less than the diameter of the first through hole on the punch, and the rotation radius of the striking plate (i.e., the straight distance from one end of the striking plate in the length direction to the rotating shaft) is less than the length of the slot along the axis of the pull rod.

[0014] Furthermore, the integral forming device for the titanium alloy casing of aero-engines also includes:

[0015] The first cylindrical pin is rotatably connected to the slot on the upper end face of the pull rod via the first cylindrical pin;

[0016] The second cylindrical pin is used to fix the die to the lower end face of the upper template.

[0017] The screws are also connected to the circumferential surfaces of the lower template and the upper template, and the screws are used for hoisting the lower template and the upper template;

[0018] Bolts are used to fix the punch to the upper end face of the lower template.

[0019] Top rod holes, multiple top rod holes are opened on the lower template at the corresponding positions of the top plate.

[0020] Alternatively, the limiting structure includes a limiting groove and a third cylindrical pin. The limiting groove is located at the lower end of the punch and communicates with the first through hole. The third cylindrical pin passes through the lower end of the pull rod and is placed in the limiting groove of the punch.

[0021] Alternatively, the striking plate has two circular holes, and the axis of rotation of the striking plate is located between the two circular holes.

[0022] A method for integrally forming a titanium alloy housing for an aero-engine, the titanium alloy housing comprising a cylindrical surface and a conical surface at each axial end of the cylindrical surface, wherein the smaller diameter end of one conical surface is connected to the cylindrical surface via a transition fillet, and the larger diameter end of the other conical surface is connected to the cylindrical surface via a transition fillet, characterized in that the integral forming process includes the following steps:

[0023] S1, blanking: using a sheet material with the same final thickness as the titanium alloy shell of the aero-engine as the blank material, and cutting the blank material into a circular ring shape;

[0024] S2, hot stretching forming, the annular material in S1 is placed into the stretching die and then hot stretched to obtain a cylindrical shape, two conical shapes, and the transition fillet at the connection between the cylindrical and conical surfaces.

[0025] S3, Machining the outer shape, machining the cylindrical surface and two conical surfaces after hot stretching and forming in S2. The machining dimensions are executed according to the drawing of the titanium alloy shell part of the aero-engine.

[0026] S4, pickling, to remove the oxide scale from the surface of the part after machining in S3.

[0027] Furthermore, in step S1, the sheet material is cut into circular ring-shaped blanks using laser cutting.

[0028] Alternatively, in S2, the aforementioned integral forming device for the titanium alloy shell of an aero-engine is used as a stretching die. After the annular blank is loaded into the stretching die, it is placed into the thermoforming equipment for hot stretching.

[0029] Furthermore, step S2 includes the following steps:

[0030] S21, rotate the beater plate to make it parallel to the axis of the tie rod, and lift the top plate upward until the upper end face of the top plate is not lower than the upper end face of the punch;

[0031] S22, Place the annular material on the top plate, wherein the inner ring hole of the annular material is fitted onto the pull rod;

[0032] S23, rotate the beater plate again to make it perpendicular to the axis of the pull rod;

[0033] S24, drive the die to move toward the punch to perform hot stretching and forming of the annular blank until the die and punch are closed.

[0034] S25, drive the die away from the punch, rotate the beater plate again to make it parallel to the axis of the tie rod, drive the top plate to move upward to eject the stretched part from the punch.

[0035] Furthermore, prior to step S21, boron nitride is applied to the convex surface of the punch, the concave surface of the die, and the surface of the annular material.

[0036] Compared with traditional methods, the forming method of the present invention can be used in the integral forming of titanium alloy shells for aero-engines. This processing method eliminates the weld seams of the parts, solves the wrinkling problem of the parts during forming, reduces two hot forming processes to one hot forming process, greatly shortens the part processing cycle, and improves the part processing efficiency.

[0037] The titanium alloy shell has now been hot-stretched and formed. The wall thickness of the formed part meets the requirements of the drawings, thus achieving the invention's purpose and technical requirements. Attached Figure Description

[0038] Figure 1 This is a two-dimensional dimensional drawing of the titanium alloy shell;

[0039] Figure 2 This is a schematic diagram showing the dimensions of the titanium alloy shell after laser cutting.

[0040] Figure 3 General drawing of the hot stretching die for titanium alloy shell;

[0041] Figure 4 This is a schematic diagram showing the fit between the punch and the tie rod.

[0042] In the diagram: 1—lower template, 2—top plate, 3—punch, 4—tie rod, 5—die, 6—upper template, 7—beater plate, 8—first cylindrical pin, 9—second cylindrical pin, 10—screw, 11—bolt, 12—third cylindrical pin. Detailed Implementation

[0043] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0044] This invention utilizes a sheet metal hot stretching forming method to process titanium alloy shells. Considering that sheet metal stretching can easily lead to material thinning, the flange edge (the outer circumference of the blank material) should not be too large during stretching. An excessively large flange edge hinders material feeding during stretching and may cause the part to thin or even crack. The final part processing route is: laser blanking → hot forming → machining → pickling, as detailed below:

[0045] (1) Blanking: Use 1mm thick sheet metal for laser two-dimensional blanking;

[0046] (2) Thermoforming: The raw material is placed into a stretching die and then hot-stretched in a thermoforming equipment;

[0047] (3) Machining the outline: Machining the outline according to the part dimensions;

[0048] (4) Pickling: Removes the oxide scale remaining after the parts are thermoformed.

[0049] Determination of part forming method: Based on the verification results of sheet metal simulation, the part is formed by hot stretching of sheet metal.

[0050] Material selection before part forming: Considering that the sheet metal needs to be thinned during stretching to form the part, relying solely on the outer diameter of the sheet metal for stretching can easily lead to thinning. Therefore, a circular hole is machined in the center of the sheet metal. This allows the sheet metal to feed simultaneously from both the inner diameter ΦD5 and the outer diameter ΦD4 during stretching, thereby reducing material thinning during stretching. Specifically, as follows... Figure 2 As shown.

[0051] Determination of part forming mold: adopted Figure 2 The shown raw material undergoes hot stretching. Because the part is processed while hot, it may stick to the upper die after stretching. Therefore, a stripping mechanism needs to be added to the stretching die design. This mechanism ensures the part can be smoothly removed as the upper die rises after stretching. The specific stretching die structure is as follows: Figure 3 As shown.

[0052] Figure 3 The punch 3 and die 5 are respectively fixed to the lower template 1 and the upper template 6 by bolts 11 and the second cylindrical pin 9. The convex surface of the punch 3 is composed of a conical surface, a transition fillet, a cylindrical surface, a transition fillet, and a conical surface connected in sequence. It is used to form the inner cylindrical surface, two inner conical surfaces, and the inner surface of the two transition fillets of the titanium alloy shell. The concave surface of the die 5 is composed of a conical surface, a transition fillet, a cylindrical surface, a transition fillet, and a conical surface connected in sequence. It is used to form the outer cylindrical surface, two outer conical surfaces, and the outer surface of the two transition fillets of the titanium alloy shell. The punch plate 7 is a rectangular plate. The midpoint of the punch plate 7 along its length is connected to the pull rod 4 by the first cylindrical pin 8. The punch plate 7 can rotate around the first cylindrical pin 8 in the through groove of the upper template 6 and the second through hole area of ​​the die 5. The punch plate 7 has two circular holes. Figure 3 Two circular holes are symmetrically distributed about the first cylindrical pin 8. Before forming, the punch plate 7 and the pull rod 4 are lifted upwards a certain distance by the circular holes on the punch plate 7. Then, the punch plate 7 is rotated around the first cylindrical pin 8, so that the punch plate 7 enters the slot of the pull rod 4. Finally, the punch plate 7 is positioned vertically (i.e., in a straight line with the pull rod 4). The blank is placed into the mold and positioned with the pull rod 4 through the circular hole (ΦD5) on the blank. After the blank is positioned, the punch plate 7 and the pull rod 4 are lifted upwards again by the circular holes on the punch plate 7. Then, the punch plate 7 is rotated to be positioned horizontally (i.e., perpendicular to the pull rod 4). Figure 4The upper platform of the thermoforming equipment drives the die 5 downward (the top plate 2 moves synchronously with the die 5 to press and stretch the annular blank). The die 5 gradually stretches the blank to form the part's profile (including two conical angles A and B, and the transition radii R1 and R2 between the two conical and cylindrical surfaces). When the die 5 and the punch 3 are closed, the upper platform of the thermoforming equipment drives the die 5 upward. If the part sticks to the die 5 after stretching, the punch plate 7 can block the part from moving upward when the die 5 moves upward, thus unloading the part. When removing the part, the pull rod 4 is pulled upward through the round hole on the punch plate 7, and the punch plate 4 is rotated to be in the vertical direction. The lifting rod of the thermoforming equipment passes through the ejector hole of the lower template 1 and pushes the top plate 2 to eject the part, which can then be removed.

[0053] like Figure 4 A limiting groove is formed on the lower end face of the punch 3, which communicates with the lower end of the first through hole on the punch 3. The pull rod 4 is placed in the first through hole, and a third cylindrical pin 12 is connected through the lower end of the pull rod 4 corresponding to the limiting groove area. The length of the third cylindrical pin 12 is greater than the diameter of the first through hole, which limits the upward lifting height of the pull rod 4. The purpose of allowing the pull rod 4 to be lifted a certain distance is to expose the groove on the pull rod 4 on the upper end face of the punch 3, so that the rotating die plate 7 can easily enter the groove without interference. The outer diameter of the upper end face of the punch 3 is greater than the inner diameter ΦD5 of the annular blank, and the length of the die plate 7 is greater than the inner diameter ΦD5 of the annular blank. This design ensures that the length of the die plate 7 can limit the part from sticking to the die 5 and rising during hot stretching.

[0054] Hot stretching forming: Before processing, the stretching die needs to be installed in the thermoforming equipment and the ejector pin needs to be leveled. That is, the ejector pin pushes the ejector plate 2 upward to be flush with or higher than the upper end face of the punch 3, and ensures that the upper end face of the ejector plate 2 is parallel to the lower end face of the die 5 and the upper end face of the punch 3 (that is, the end face gap of the clamping annular blank is consistent and there is no skew). This ensures that the blank holder force is uniform during stretching. Boron nitride should be evenly applied to the blank and the stretching die to reduce the frictional resistance during hot stretching and facilitate the stretching and feeding of the part. During the processing of the part, the blank holder force can be adjusted appropriately by observing the feeding situation of the part to ensure the final material thickness requirement of the part, and finally complete the thermoforming of the part.

[0055] Machining and pickling are performed using machining methods. Figure 1 Medium dimensions D1, D2, D3 and H are pickled after machining (the transition fillets R1 and R2 can be corrected during machining).

[0056] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A device for integral molding of titanium alloy housing for aero-engines, characterized in that, include: Template (1); Upper template (6), the upper template (6) has a through groove; The punch (3) includes a convex surface for forming the inner surface of the titanium alloy shell. The punch (3) is fixed on the upper end face of the lower template (1). A first through hole coaxial with the punch (3) is opened on the punch (3). The die (5) includes a concave surface for forming the outer surface of the titanium alloy shell. The die (5) is fixed to the lower end face of the upper template (6). The bottom of the concave surface of the die (5) has a second through hole that communicates with the through groove of the upper template (6). Top plate (2), the top plate (2) is an annular part, and the punch (3) is placed in the inner annular surface of the top plate (2); A pull rod (4) is placed in the first through hole of the punch (3). The upper end of the pull rod (4) extends from the opening of the first through hole away from the lower template (1) and extends at least into the second through hole. A groove is opened on the upper end face of the pull rod (4). The groove extends along the axial direction of the pull rod (4). A limiting structure is provided at the lower end of the pull rod (4) to prevent the pull rod (4) from disengaging from the first through hole. The striking plate (7) is rotatably connected to the slot on the upper end face of the pull rod (4). The length of the striking plate (7) is greater than the diameter of the first through hole on the punch (3), the width of the striking plate (7) is less than the diameter of the first through hole on the punch (3), and the rotation radius of the striking plate (7) is less than the length of the slot along the axis of the pull rod (4).

2. The integral forming device for aero-engine titanium alloy housing according to claim 1, characterized in that, Also includes: The first cylindrical pin (8) and the plate (7) are rotatably connected to the slot on the upper end face of the pull rod (4) through the first cylindrical pin (8); The second cylindrical pin (9) is used to fix the die (5) to the lower end face of the upper template (6); The screw (10) is also connected to the circumferential surfaces of the lower template (1) and the upper template (6). Bolt (11) and punch (3) are fixed to the upper end face of the lower template (1) by the bolt (11); Top rod holes, multiple top rod holes are opened on the lower template (1) at the position corresponding to the top plate (2).

3. The integral forming device for aero-engine titanium alloy housing according to claim 1, characterized in that: The limiting structure includes a limiting groove and a third cylindrical pin (12). The limiting groove is opened at the lower end of the punch (3) and communicates with the first through hole. The third cylindrical pin (12) passes through the lower end of the pull rod (4) and is placed in the limiting groove of the punch (3).

4. The integral forming device for aero-engine titanium alloy housing according to claim 1, characterized in that: The striking plate (7) has two round holes, and the axis of rotation of the striking plate (7) is located between the two round holes.

5. A method for integrally forming a titanium alloy housing for an aero-engine, the titanium alloy housing comprising a cylindrical surface and a conical surface at each axial end of the cylindrical surface, wherein the smaller diameter end of one conical surface is connected to the cylindrical surface via a transition fillet, and the larger diameter end of the other conical surface is connected to the cylindrical surface via a transition fillet, characterized in that... The integral molding process includes the following steps: S1, blanking: using a sheet material with the same final thickness as the titanium alloy shell of the aero-engine as the blank material, and cutting the blank material into a circular ring shape; S2, hot stretching forming, the annular material in S1 is placed into the stretching die and then hot stretched to obtain a cylindrical shape, two conical shapes, and the transition fillet at the connection between the cylindrical and conical surfaces. S3, Machining the outer shape, machining the cylindrical surface and two conical surfaces after hot stretching and forming in S2. The machining dimensions are executed according to the drawing of the titanium alloy shell part of the aero-engine. S4, pickling, to remove the oxide scale from the surface of the parts after machining in S3; In step S2, the integral forming device for the titanium alloy shell of the aero-engine described in claim 1 is used as the stretching mold. After the annular blank is loaded into the stretching mold, it is placed into the thermoforming equipment for hot stretching.

6. The method for integral forming of a titanium alloy housing for an aero-engine according to claim 5, characterized in that: In step S1, laser cutting is used to cut the sheet material into circular rough pieces.

7. The method for integral forming of a titanium alloy housing for an aero-engine according to claim 5, characterized in that: S2 includes the following steps: S21, rotate the beater plate (7) to make it parallel to the axis of the tie rod (4), and lift the top plate (2) upward until the upper end face of the top plate (2) is not lower than the upper end face of the punch (3); S22, place the annular material on the top plate (2), wherein the inner ring hole of the annular material is fitted onto the pull rod (4); S23, rotate the beater (7) again to make it perpendicular to the axis of the pull rod (4); S24, drive the die (5) to move toward the punch (3) to perform hot stretching and forming of the annular material until the die (5) and the punch (3) are closed; S25, drive the die (5) away from the punch (3), rotate the beater (7) again to make it parallel to the axis of the tie rod (4), drive the top plate (2) to move upward and push the stretched part out from the punch (3).

8. The method for integral forming of a titanium alloy housing for an aero-engine according to claim 7, characterized in that: Before step S21, boron nitride is applied to the convex surface of the punch (3), the concave surface of the die (5), and the surface of the annular material.

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