Double-blind-hole fan shaft forging die and forming process

Abstract

A forging die for a double-blind-hole fan shaft, comprising a fixed base, a lower die is arranged on the fixed base, a semi-spindle-shaped cavity is arranged in the lower die, and a first blind-hole forging part is arranged at the bottom; the forging die further comprises an upper die, the upper die is detachably installed at the power output end of a forging press and can be slidably connected with the inner wall of the semi-spindle-shaped cavity, and the upper die comprises a flat pressing upper die and a forging upper die. This die can realize the integral forming of the double-blind-hole fan shaft through one-time heating and two working steps, and the obtained finished part has good tissue uniformity, complete streamline conformity, and improved fatigue performance. The present invention also provides a forming process for a double-blind-hole fan shaft.

Description

Technical Field

[0001] The present invention belongs to the field of aeroengines, and particularly relates to a forging die and forming process for a double-blind-hole fan shaft. Background Art

[0002] With the rapid development of aviation technology, the power performance of aero turbofan engines has been continuously improved. As the main component providing power for the engine, the fan shaft of the engine needs to bear huge torque loads during operation. The fan shaft needs to transmit the turbine power to the fan to drive the large-sized fan to rotate and generate thrust. The fan shafts of traditional engines mostly involve a gradually changing drum-shaped structure. With the rapid development of fan shaft design, a necked bottle-shaped fan shaft with complex structural features such as unequal-diameter inner diameters, variable cross-sections inside and outside, convex platforms on the outer wall end faces, and convex platforms in the middle of the inner wall has become the current research direction.

[0003] Traditional fan shafts can be formed by processes such as combined die forging or open die forging. Solid forging is adopted and then the rod part is freely drawn out and the head part is die forged respectively. The process is simple, the equipment requirements are low, and it is easy to operate. However, the inventor has recognized that when dealing with new fan shafts with complex structures, such as semi-spindle-shaped fan shafts with double blind holes, the existing simple dies and traditional processes have problems such as small deformation amounts, uneven stress distribution, and local air burning during multi-pass heating, resulting in poor tissue uniformity of the finished product, damage to the deformed tissue streamline, and low material utilization rate. Therefore, it is very necessary to provide an efficient forging die for a double-blind-hole fan shaft. Summary of the Invention

[0004] The purpose of the present invention is to provide a forging die for a double-blind-hole fan shaft to achieve the integral forming of a semi-spindle-shaped fan shaft with double blind holes, improve the tissue uniformity and streamline integrity of the fan shaft forging, and improve production efficiency and finished product quality. The present invention also provides a forming process for a double-blind-hole fan shaft.

[0005] According to one aspect of an embodiment of the present invention, a forging die for a double-blind-hole fan shaft is provided, including a fixed base, a lower die is arranged on the fixed base, a semi-spindle-shaped cavity is arranged in the lower die, and a first blind-hole forging part is arranged at the bottom of the semi-spindle-shaped cavity; the forging die for the double-blind-hole fan shaft further includes an upper die, the upper die is detachably installed at the power output end of a forging press and can be slidably connected with the inner wall of the semi-spindle-shaped cavity. The upper die includes a flat pressing upper die or a forging upper die, and a second blind-hole forging part is arranged on the forging upper die. By using the first blind-hole forging part and the second blind-hole forging part, a semi-spindle-shaped fan shaft body with double blind holes can be forged by sequential heating, saving processing costs and avoiding local air burning of the material.

[0006] Further, the first blind hole forging part includes a connecting part and a first blind hole rod. The connecting part is detachably installed on the lower die, and the first blind hole rod is arranged on the upper surface of the connecting part. While forming the semi-spindle-shaped profile of the fan shaft, the forging of the first blind hole at the lower part can be completed through the first blind hole rod. When the first blind hole does not need to be forged, the first blind hole forging part can be removed.

[0007] Further, a necking part is arranged at the lower part of the semi-spindle-shaped cavity. The necking part is configured as an annular block installed on the inner wall of the semi-spindle-shaped cavity, and the side surface of the connecting part abuts against the annular block. Through the necking part, the forming of the necking structure at one end of the fan shaft can be completed at one time, and the detachable annular block is convenient for replacement and die repair.

[0008] Further, a special-shaped forging part is also detachably installed in the semi-spindle-shaped cavity. The special-shaped forging part can be circumferentially disassembled into at least two arc-shaped forging parts, and the radian of the arc-shaped forging part does not exceed π. Through the detachable special-shaped forging part, a boss can be directly forged on the fan shaft, avoiding subsequent cutting processing.

[0009] Further, the special-shaped forging part includes a stepped forging part and a protruding forging part. The inner diameter of the protruding forging part is larger than the inner diameter of the necking part, and the inner diameter of the stepped forging part gradually expands from the end close to the protruding forging part to the distal end. The variable cross-section forging of the fan shaft is realized through the special-shaped forging part.

[0010] Further, the stepped forging part and the protruding forging part are configured to be integrally formed, simplifying the die structure.

[0011] Optionally, the second blind hole forging part includes a connecting seat, which can be detachably installed on the power output end of the forging press. The second blind hole rod is arranged on the lower surface of the connecting seat; the second blind hole forging part also includes an end face forging block, which can be slidably connected to the inner wall of the semi-spindle-shaped cavity. The second blind hole rod is arranged in the end face forging block and is slidably connected to the end face forging block. After the forming forging of the first blind hole is completed, the forging of the second blind hole at the upper part can be completed through the second blind hole rod without demolding.

[0012] Further, an outer end face forging part is arranged on the circumferential side of the bottom of the end face forging block. The end face forging part can form the outer end face structure of the fan shaft as required, saving the time and cost of subsequent processing.

[0013] According to another aspect of the embodiments of the present invention, a double-blind hole fan shaft forming process is provided. Using the double-blind hole fan shaft forging die described above, the double-blind hole two-way extrusion near-net forming manufacturing of the fan shaft is carried out through one hot working and two working steps. The process includes the following steps:

[0014] S1. Place the billet heated to the extrusion temperature into the semi-spindle cavity of the preheated double-blind-hole fan shaft forging die, and move the flat pressing upper die downward to extrude the billet, so that the billet forms a first blind hole under the action of the first blind hole forging part;

[0015] S2. The flat pressing upper die returns to the initial position, disassemble the flat pressing upper die and replace it with the forging upper die, and the forging upper die presses down, so that the billet forms a second blind hole under the action of the second blind hole forging part.

[0016] Further, the forming process further includes the following steps:

[0017] S3. After the forging finished product is demolded, radially remove the arc-shaped forging parts that are demolded with the double-blind-hole fan shaft respectively. Description of the Drawings

[0018] Figure 1 Shown is a schematic structural diagram of a finished double-blind-hole fan shaft in an embodiment;

[0019] Figure 2 Shown is a schematic diagram of forging the first blind hole using a double-blind-hole fan shaft forging die in an embodiment;

[0020] Figure 3 Shown is a schematic diagram of forging the second blind hole using a double-blind-hole fan shaft forging die in an embodiment.

[0021] Meanings of the reference numerals: 100 - first blind hole; 200 - second blind hole; 300 - fixed base; 400 - lower die; 410 - semi-spindle cavity; 420 - flat pressing upper die; 430 - forging upper die; 500 - first blind hole forging part; 510 - connecting part; 520 - first blind hole rod; 600 - second blind hole forging part; 610 - end face forging block; 611 - outer end face forging part; 630 - connecting seat; 700 - necking part; 710 - annular block; 800 - special-shaped forging part; 810 - variable diameter forging part; 820 - convex forging part.

[0022] The purpose of the above drawings is to make a detailed description of the technical features of the present invention, so that those skilled in the art can understand the technical concept of the present invention, rather than aiming to limit the present invention. It should be understood that the above drawings only schematically mark the structures related to the technical features of the present invention, and do not strictly draw all the part structures and detailed features according to the scale. Detailed Embodiments

[0023] The following further describes the present invention in detail through specific embodiments in conjunction with the drawings.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the present invention; the terms "comprising" and "having" and their equivalent expressions in the description of this specification, claims and the above drawings are intended to cover non-exclusive inclusion relationships.

[0025] Reference to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art should be able to understand that the embodiments herein can be combined with other embodiments without structural conflicts.

[0026] In the description herein, terms indicating orientation or positional relationships such as "upper", "lower", "circumferential", "radial", etc. are for the purpose of accurately describing the embodiments and simplifying the description, rather than limiting the parts or structures involved to having a specific orientation, being installed or operated in a specific orientation, and should not be construed as a limitation on the embodiments herein.

[0027] Unless otherwise clearly specified and defined, technical terms such as "installation", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a rigid connection, an elastic connection, a detachable connection, or integrated. For those skilled in the art, the specific meanings of the above terms in the description of the embodiments can be understood according to specific circumstances.

[0028] An embodiment of the present invention, as Figure 2 and Figure 3 shown, provides a forging die for a double-blind-hole fan shaft, which is used to forge a fan shaft as Figure 1 shown. Both ends of the fan shaft respectively have a first blind hole 100 and a second blind hole 200, and the first blind hole 100 and the second blind hole 200 are drilled through by separate processes in subsequent processing.

[0029] Referring to Figure 2 and Figure 3 , the die includes a fixed base 300, and a lower die 400 is arranged on the fixed base 300. The fixed base 300 fixes the lower die 400 at the fixed end of the forging equipment. A semi-spindle-shaped cavity 410 is arranged in the lower die 400. The main body of the cavity includes at least two columnar wall surfaces with decreasing inner diameters, and the wall surfaces are transitioned by conical surfaces, which is used to forge the main external contour of the fan shaft; a first blind hole forging part 500 is arranged at the bottom of the lower die 400, which is used to forge the first blind hole. Combining Figure 2 and Figure 3, the mold further includes an upper mold detachably installed at the power output end of a forging press, including a flat pressing upper mold 420 and a forging upper mold 430, and the upper mold can be slidably connected to the inner wall of the semi-spindle cavity 410.

[0030] Optionally, the first blind hole forging part 500 includes a connecting part 510 and a first blind hole rod 520. The first blind hole forging part 500 is fixedly connected to the lower mold 400 through the connecting part 510, and the forging function of the first blind hole 100 is realized through the first blind hole rod 520.

[0031] Further optionally, a necking part 700 is further provided at the lower part of the semi-spindle cavity 410 for forming a necking structure at one end of the fan shaft. The necking part 700 includes an annular block 710 fixed to the inner wall of the semi-spindle cavity, and the annular block 710 is connected to the side surface of the connecting part 510.

[0032] Further optionally, a detachable special-shaped forging part 800 is further provided inside the semi-spindle cavity 410. The special-shaped forging part 800 can be disassembled circumferentially into at least 2 annular forging parts, and the radian of each annular forging part does not exceed π. For example, it can be disassembled into 2 semi-circles or evenly divided into 3 arc-shaped forging parts of 120° for disassembly during demolding.

[0033] Further optionally, the special-shaped forging part 800 includes an integrally formed variable-diameter forging part 810 and a convex forging part 820. Among them, the inner diameter of the convex forging part 820 is larger than the inner diameter of the necking part 700 for forging the external convex structure near the end of the fan shaft; the inner diameter of the variable-diameter forging part 810 gradually expands from the end close to the convex forging part 820 to the distal end for forging the conical surface structure on the fan shaft.

[0034] Optionally, the second blind hole forging part 600 includes a connecting seat 630, and the connecting seat 630 can be detachably installed at the power output end of the forging press; a second blind hole rod 620 is provided on the lower surface of the connecting seat 630 for forging the second blind hole 200; the second blind hole forging part 600 further includes an end face pressing block 610 that can be slidably connected inside the semi-spindle cavity 410 for providing end face pressure during forging the second blind hole. The second blind hole rod 620 is inserted into the end face pressing block 610 and is slidably connected to it.

[0035] Further optionally, an outer end face pressing part 611 is provided on the circumferential side of the bottom of the end face pressing block 610, which can press out the required shape of the outer end face of the fan shaft according to design requirements to reduce the workload of subsequent processing.

[0036] According to another embodiment of the present invention, a double-blind hole fan shaft forming process is provided, which uses the double-blind hole fan shaft forging mold in any of the foregoing embodiments to perform integrated two-way extrusion near-net forming manufacturing of the double-blind hole fan shaft.

[0037] Furthermore, the forming process includes the following steps:

[0038] S0. Heat the bar blank to the initial extrusion temperature and preheat the die. The diameter of the bar blank should be able to pass through the narrowest cross-section of the semi-spindle-shaped cavity;

[0039] S1. Take the heated bar blank out of the furnace, apply a lubricant on the operating table, such as applying a glass lubricant in a roller coating manner, and use a manipulator to transfer the bar blank into the semi-spindle-shaped cavity 410 of the die; install a flat pressing upper die 420 on the forging press, and extrude the bar blank so that the bar blank forms a first blind hole 100 under the action of the first blind hole forging part 500;

[0040] S2. The flat pressing upper die 420 resets and is replaced by a forging upper die 430, and the bar blank is extruded again so that the bar blank forms a second blind hole 200 under the action of the second blind hole forging part 600;

[0041] S3. Demold the forged product, and respectively remove each arc-shaped forging part of the special-shaped forging part 800 that is demolded with the double-blind hole fan shaft along the radial direction to obtain the finished product.

[0042] During the forging process, the first blind hole forging part 500 and the second blind hole forging part 600 respectively complete the forming of the first blind hole 100 and the second blind hole 200; the annular block 710 forms a necking part at the lower end of the fan shaft; the special-shaped forging part 800 forms a variable cross-section part and an outer convex platform structure of the fan shaft. The entire forming process only heats the bar blank and the die once, and through the combination of forward extrusion and backward extrusion in two working steps for overall forming, a nearly net-shaped complex fan shaft structure is directly obtained. This process enables the finished part to be deformed fully and evenly, with good tissue uniformity, complete and conforming streamline, and nearly net-shaped inner and outer surfaces, which can improve the rotational fatigue performance of the fan shaft part, achieve an average crystal grain size of the forging in the forged state greater than or equal to 5 levels, and a strength fluctuation within 1.5%.

[0043] It should be understood that the purpose of the above embodiments is to make a detailed description of the present invention in combination with the drawings, so that those skilled in the art can understand the technical concept of the present invention, rather than aiming to limit the present invention. Within the scope of the claims of the present invention, optimizing or equivalently replacing the involved part structures and method steps all fall within the protection scope of the present invention.

Claims

1. A forging die for a double-blind-hole fan shaft, characterized in that: It includes a fixed base, a lower die is arranged on the fixed base, a semi-spindle-shaped cavity is arranged in the lower die, and a first blind-hole forging part is arranged at the bottom of the semi-spindle-shaped cavity; The forging die for the double-blind-hole fan shaft further includes an upper die, the upper die is detachably installed at the power output end of the forging press and can be slidably connected to the inner wall of the semi-spindle-shaped cavity. The upper die includes a flat pressing upper die and a forging upper die, and a second blind-hole forging part is arranged on the forging upper die; The first blind-hole forging part includes a connecting part and a first blind-hole rod, the connecting part is detachably installed with the lower die, and the first blind-hole rod is arranged on the upper surface of the connecting part; A necking part is arranged at the lower part of the semi-spindle-shaped cavity, and the necking part is configured as an annular block installed on the inner wall of the semi-spindle-shaped cavity, and the side surface of the connecting part is connected with the annular block; An irregular forging part is also detachably installed in the semi-spindle-shaped cavity, and the irregular forging part can be circumferentially disassembled into at least 2 arc-shaped forging parts, and the radian of the arc-shaped forging part does not exceed π.

2. The double-blind-hole fan shaft forging die according to claim 1, wherein The irregular forging part includes a variable-diameter forging part and a convex forging part, the inner diameter of the convex forging part is larger than the inner diameter of the necking part, and the inner diameter of the variable-diameter forging part gradually expands from one end close to the convex forging part to the distal end.

3. The forging die for a double-blind-hole fan shaft according to claim 2, characterized in that, The variable-diameter forging part and the convex forging part are configured to be integrally formed.

4. The forging die for the double-blind-hole fan shaft according to claim 1, characterized in that The second blind-hole forging part includes a connecting seat, the connecting seat can be detachably installed at the power output end of the forging press, and a second blind-hole rod is arranged on the lower surface of the connecting seat; the second blind-hole forging part further includes an end face forging block, the end face forging block can be slidably connected to the inner wall of the semi-spindle-shaped cavity, and the second blind-hole rod is arranged in the end face forging block and is slidably connected to the end face forging block.

5. The double-blind-hole fan shaft forging die according to claim 4, wherein An outer end face forging part is arranged on the circumferential side of the bottom of the end face forging block.

6. A double-blind-hole fan shaft forming process, characterized in that, Using the forging die for the double-blind-hole fan shaft according to any one of claims 1 to 5, the near-net forming manufacturing of the double-blind-hole of the fan shaft by double-sided extrusion through one heating and two working steps includes the following steps: S1. Put the billet heated to the extrusion temperature into the semi-spindle-shaped cavity of the preheated forging die for the double-blind-hole fan shaft, and move the flat pressing upper die downward to extrude the billet, so that the billet forms a first blind hole under the action of the first blind-hole forging part; S2. The flat pressing upper die returns to the initial position, the flat pressing upper die is disassembled and replaced with the forging upper die, and the forging upper die is pressed downward, so that the billet forms a second blind hole under the action of the second blind-hole forging part.

7. The double-blind-hole fan shaft forming process according to claim 6, wherein, It also includes the following steps: S3. After the forged product is demolded, the arc-shaped forging parts that are demolded with the double-blind-hole fan shaft are respectively removed along the radial direction.

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