A forging method for increasing the service life of aircraft landing gear parts

Abstract

The invention discloses a forging forming method for improving the service life of an aircraft landing gear. The method uses a tooling component to be set and cooperates with a forging process, and uses the tooling to repeatedly upset and press a blank to form an asymmetric structure blank. The invention can upset a rod-shaped blank at an inclined angle relative to the upsetting direction. Under the blocking effect of the side wall of the lower die, the rod-shaped blank will flow in a target direction, so that most of the material flows to the other side of the lower die. By reasonably setting the characteristic parameters of the tooling, the distribution ratio of the material flowing to the left and right sides can be controlled, so that the material can be fully utilized and the waste of the material can be reduced. Compared with the prior art that adopts the method of offsetting the upper and lower flat anvils to achieve material gathering through a single-side lower step, the invention is simple to operate, can reduce the forging cost, ensure the integrity of the metal streamline, and improve the service life of the forging.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft landing gear manufacturing, and in particular to a forging forming method for improving the service life of an aircraft landing gear. Background Art

[0002] Aircraft landing gear is an important safety functional component of the aircraft. It is an important support system for the aircraft's takeoff, landing, ground taxiing and parking. It is a key and important load-bearing component of the aircraft.

[0003] The outer tube part of the aircraft landing gear is a key load-bearing part of the aircraft. It is the largest, heaviest and most complex component in the landing gear system. The forgings used to process this part must ensure streamlined shape during the forging process and have strict process stability and controllability. Therefore, very high requirements are placed on the manufacturing process of the aircraft landing gear outer tube forgings.

[0004] For asymmetric complex landing gear forgings, such as typical asymmetric "L"-shaped parts, which include a rod and a head, the head is not symmetrical relative to the center line of the rod, and there is a height difference between the head and the rod, this type of forging is difficult to form. At present, the main production method for this type of parts is dressing, which makes the asymmetric structure symmetrical or the upper and lower anvils staggered during forging deformation. The dressing method is to add materials to eliminate the asymmetric structure and simplify production, but ultimately it is necessary to remove excess material on one side of the head, resulting in the streamline being cut off and a lot of material waste; the upper and lower anvils are offset to achieve material gathering through a single-sided lower step. This method has poor controllability and complex operation; the above problems will reduce the service life of components and are not conducive to the long-life manufacturing of landing gear components. Summary of the invention

[0005] To solve the above problems, the purpose of the present invention is to provide a forging forming method for improving the service life of aircraft landing gear. The method is simple to operate, with less material waste, and avoids the cutting of part streamlines, thereby improving fatigue performance and extending service life.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A forging method for increasing the life of an aircraft landing gear comprises the following steps:

[0008] (1) Tooling preparation

[0009] The tooling includes three sets of tooling, namely the first tooling, the second tooling and the third tooling;

[0010] The first tooling includes a flat anvil and a lower die, the lower die is provided with a discharge cavity opening upward, the discharge cavity includes a bottom, a first side wall and a second side wall, the first side wall is perpendicular to the bottom, an angle β is formed between the second side wall and the first side wall, an angle ε is formed between the bottom of the discharge cavity and the horizontal line of the lower die, the top of the lower die located on the first side wall is higher than the top of the lower die located on the second side wall by a characteristic height H, a chamfer γ is formed between the upper part of the first side wall and the top surface of the lower die, a chamfer θ is formed between the upper part of the second side wall and the top surface of the lower die, and an angle α is formed between the center line of the discharge cavity and the center line of the lower die;

[0011] The second tooling comprises an upper flat anvil and a lower flat anvil, the upper flat anvil and the lower flat anvil have the same structure and are symmetrically arranged along a horizontal plane;

[0012] The third tooling comprises an upper anvil and a lower anvil, the upper anvil and the lower anvil have the same structure and are symmetrically arranged along the horizontal plane, and are rectangular as a whole, with a chamfer δ formed between the anvil surface and one side surface;

[0013] (2) Forging

[0014] (21) Obtain a rod-shaped blank, and place the rod-shaped blank in the discharge cavity of the lower die, control the flat anvil to press the rod-shaped blank, and upset the head of the rod-shaped blank located outside the discharge cavity; because there is an angle α between the center line of the discharge cavity and the center line of the lower die, the metal flow direction during upsetting can be guided, and then combined with the characteristic height H, the metal flows in a direction away from the characteristic height, thereby obtaining material distribution and gathering in a specific direction, and the chamfer θ and the chamfer γ form a certain angle between the head and the rod to form an asymmetric L-shaped head, and obtain an inclined blank after upsetting;

[0015] (22) placing the oblique blank between an upper flat anvil and a lower flat anvil that are arranged opposite to each other, so that the unnecessary side material of the head of the oblique blank faces the anvil surface, and pressing the side material of the oblique blank toward the required side by the upper flat anvil and the lower flat anvil;

[0016] (23) placing the inclined blank rod portion pressed by the second tooling into the discharge cavity, repeating steps (21) to (22), repeatedly upsetting and pressing, guiding the metal at the blank head to flow away from the characteristic height direction, thereby forming a blank head and obtaining an eccentric blank;

[0017] (24) placing the eccentric blank between an upper anvil and a lower anvil that are arranged opposite to each other, and pressing the rod of the eccentric blank in the length direction by the extrusion force generated when the upper anvil and the lower anvil are closed, thereby shaping the rod, and finally obtaining an asymmetric structure blank;

[0018] (25) The rough blank is then heated and die-forged to obtain a final forging of an aircraft landing gear outer tube having metal streamlines.

[0019] Furthermore, the angle β and the angle ε of the lower die are both 1° to 5°, the chamfer θ and the chamfer γ are both 30° to 90°, the angle α is 1° to 10°, and the characteristic height is ≥50 mm.

[0020] Furthermore, the chamfer angle δ of the third tooling is 20° to 60°.

[0021] Furthermore, the anvil surface and two side surfaces of the upper anvil and the lower anvil are both chamfered with a chamfer angle δ.

[0022] The present invention can upset the rod-shaped blank at an inclined angle relative to the upsetting direction. Under the blocking effect of the side wall of the lower die, the rod-shaped blank will flow toward the target direction, so that most of the material flows to the other side of the lower die. By reasonably setting the characteristic parameters of the tooling, the distribution ratio of the material flowing to the left and right sides can be controlled, so that the material can be fully utilized and the waste of material can be reduced. Compared with the prior art that adopts the method of offsetting the upper and lower flat anvils to achieve material gathering through a single-sided lower step, the present invention is simple to operate, can reduce forging costs, ensure the integrity of metal streamlines, and increase the life of forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the first tooling structure of the present invention.

[0024] Figure 2 It is a schematic diagram of the second tooling structure of the present invention.

[0025] Figure 3 It is a schematic diagram of the third tooling structure of the present invention.

[0026] Figure 4 It is a schematic diagram of the forging forming process of the present invention.

[0027] Markings in the figure: 100, flat anvil; 200, lower die; 210, discharge cavity; 211, bottom; 212, first side wall; 213, second side wall; 220, characteristic height; 300, second tooling; 400, third tooling. DETAILED DESCRIPTION

[0028] A forging method for increasing the life of an aircraft landing gear provided in this embodiment comprises the following steps:

[0029] (1) Tooling preparation

[0030] The tooling described in this embodiment includes three sets of tooling, namely a first tooling, a second tooling 300 and a third tooling 400. The three sets of tooling cooperate with each other to forge a forging with an asymmetric structure, without the need for dressing or cutting.

[0031] The first tool is mainly used for forging the blank to form an asymmetric head structure, such as Figure 1As shown, it includes a flat anvil 100 and a lower die 200. The flat anvil 100 adopts the flat anvil 100 tooling of the prior art, and cooperates with the lower die 200 to apply forging force to the blank to form it; the lower die 200 is provided with a discharge cavity 210 with an opening upward, and the discharge cavity 210 includes a bottom 211, a first side wall 212 and a second side wall 213. The first side wall 212 is perpendicular to the bottom 211, and there is an angle β between the second side wall 213 and the first side wall 212, and the angle β is 1° to 5°; there is an angle ε between the bottom 211 of the discharge cavity 210 and the horizontal line of the lower die 200, and the angle ε is 1° to 5°; the top of the lower die 200 located at the first side wall 212 is larger than that located at the bottom The top of the lower die 200 of the second side wall 213 is higher than a characteristic height 220H, and the characteristic height 220H is ≥50mm. There is a chamfer γ between the upper part of the first side wall 212 and the top surface of the lower die 200, and the angle of the chamfer γ is 30°~90°; there is a chamfer θ between the upper part of the second side wall 213 and the top surface of the lower die 200, and the angle of the chamfer θ is 30°~90°; there is an angle α between the center line of the discharge cavity 210 and the center line of the lower die 200, and the angle α is 1~10°; by setting the position, angle and characteristic height 220 of the discharge cavity 210, during the forging process, the billet metal can be moved according to the set flow direction to achieve asymmetric head forging.

[0032] The second tool 300 is mainly used to press the side material of the inclined blank to the required side, such as Figure 2 As shown, it comprises an upper flat anvil and a lower flat anvil. The upper flat anvil and the lower flat anvil of this embodiment adopt the flat anvil tooling assembly of the prior art. The upper flat anvil and the lower flat anvil have the same structure, and the anvil surface thereof is a smooth plane.

[0033] The third tool 400 is mainly used to shape the rod of the eccentric blank to make it longer. Figure 3 As shown, it includes an upper anvil and a lower anvil, which are symmetrical along the horizontal plane and are rectangular as a whole. A chamfer δ is formed between the anvil surface and one side surface, and the angle of the chamfer δ is 20 to 60 degrees, which can ensure that the blank will not have defects such as folding and tearing at the transition position during drawing. For ease of installation, the anvil surface and the two vertical side surfaces form chamfers with the same angle. At the same time, the upper anvil and the lower anvil surface forge and shape the rod to extend it.

[0034] (2) Forging

[0035] The tooling of step (1) is installed on a forging machine, and cooperates with a robot arm to process the rod-shaped blank into an outer cylinder forging with an asymmetric head, such as Figure 4 As shown, forging includes the following steps:

[0036] (21) Obtain a rod-shaped blank A, and place the rod-shaped blank in the discharge cavity 210 of the lower die 200, control the flat anvil 100 to press the rod-shaped blank, and upset the head of the rod-shaped blank outside the discharge cavity 210; because there is an angle α between the center line of the discharge cavity 210 and the center line of the lower die 200, the metal flow direction during upsetting can be guided, and then combined with the characteristic height H, it can flow in a direction away from the characteristic height 220, thereby obtaining material distribution and gathering in a specific direction, and the chamfer θ and chamfer γ can form a certain angle between the head and the rod, thereby forming an asymmetric L-shaped head, and obtaining an inclined blank B; the angle β between the first side wall 212 and the second side wall 213 of the lower die 200 facilitates the inclined blank to move to the discharge cavity 210.

[0037] (22) placing the oblique blank between the upper flat anvil and the lower flat anvil that are arranged opposite to each other, so that the unnecessary side material of the blank head faces the anvil surface, and the side material of the eccentric blank is pressed toward the required side by the upper flat anvil and the lower flat anvil to obtain the oblique blank C, thereby further realizing the material separation;

[0038] (23) Place the stem of the inclined blank C into the discharge cavity 210, repeat steps (21) to (22), repeatedly upsetting and flattening, and guide the metal at the head of the blank to flow away from the characteristic height toward the lower die 200 until the blank head is formed, thereby producing an eccentric blank D.

[0039] (24) The eccentric blank D is placed between the upper anvil and the lower anvil which are arranged opposite to each other. Due to the height difference between the head and the rod, in order to ensure that the metal streamlines follow the shape in the transition area, the chamfer δ of the anvil can ensure that the blank will not have defects such as folding and tearing at the transition position during drawing. Through the extrusion effect generated when the anvil is closed, the material of the "L"-shaped blank with a short rod is pressed in the length direction, thereby completing the drawing and forming, and finally obtaining an asymmetric structure blank E.

[0040] (25) The obtained blank E has good size and surface quality control, so it does not need machining to remove flaws, mill the shape, or other processing steps that damage the streamlines. It can directly proceed to subsequent heating, die forging, and other processes, and can obtain a die forging with a complete metal streamline.

[0041] The present embodiment adopts multiple sets of tooling, and selectively guides the flow direction of the metal by adjusting the characteristic structural parameters. The flat anvil 100 performs local upsetting on the rod-shaped blank along the direction of the center line of the discharge cavity 210 of the lower die 200. The end material of the rod-shaped blank will flow in the target metal flow direction under the upsetting force of the flat anvil 100, so that most of the material flows to one side of the lower die 200, while the other side is relatively less. By reasonably setting the characteristic angle α, the distribution ratio of the material flowing to the left and right sides can be controlled, so as to obtain an inclined blank of the required size. The inclined blank is then stretched and formed under the action of the second tooling 300 (upper flat anvil and lower flat anvil) and the third tooling 400 (upper die anvil and lower die anvil), and finally a target blank with an asymmetric structure is obtained. The target blank has better size and surface quality control, and does not require machining to remove defects, milling the shape and other processing steps that destroy the streamline. It can be subjected to subsequent heating, die forging and other processes, and can obtain a die forging with a completed metal streamline.

[0042] This embodiment can fully utilize materials and reduce material waste. Compared with the method of achieving material gathering through a single-side lower step by staggered upper and lower flat anvils 100, the method provided by this embodiment is simple to operate and the internal metal streamlines of the forgings are better.

[0043] The above description is only a preferred implementation manner of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention should be included in the protection scope of the present invention.

Claims

1. A forging method for increasing the life of an aircraft landing gear, characterized in that: The steps include: (1) Tooling preparation The tooling includes three sets of tooling, namely the first tooling, the second tooling and the third tooling; The first tooling includes a flat anvil and a lower die, the lower die is provided with a discharge cavity opening upward, the discharge cavity includes a bottom, a first side wall and a second side wall, the first side wall is perpendicular to the bottom, an angle β is formed between the second side wall and the first side wall, an angle ε is formed between the bottom of the discharge cavity and the horizontal line of the lower die, the top of the lower die located on the first side wall is higher than the top of the lower die located on the second side wall by a characteristic height H, a chamfer γ is formed between the upper part of the first side wall and the top surface of the lower die, a chamfer θ is formed between the upper part of the second side wall and the top surface of the lower die, and an angle α is formed between the center line of the discharge cavity and the center line of the lower die; the angle β and the angle ε of the lower die are both 1° to 5°, the chamfer θ and the chamfer γ are both 30° to 90°, the angle α is 1° to 10°, and the characteristic height H is ≥50mm; The second tooling comprises an upper flat anvil and a lower flat anvil, the upper flat anvil and the lower flat anvil have the same structure and are symmetrically arranged along a horizontal plane; The third tooling includes an upper anvil and a lower anvil, the upper anvil and the lower anvil have the same structure and are symmetrically arranged along the horizontal plane, and are rectangular as a whole, with a chamfer δ formed between the anvil surface and a side surface; the chamfer δ of the third tooling is 20° to 60°; (2) Forging (21) Obtain a rod-shaped blank, and place the rod-shaped blank in the discharge cavity of the lower die, control the flat anvil to press the rod-shaped blank, and upset the head of the rod-shaped blank located outside the discharge cavity; because there is an angle α between the center line of the discharge cavity and the center line of the lower die, the metal flow direction during upsetting can be guided, and then combined with the characteristic height H, the metal flows in a direction away from the characteristic height H, thereby obtaining material distribution and gathering in a specific direction, and the chamfer θ and the chamfer γ form a certain angle between the head and the rod to form an asymmetric L-shaped head, and obtain an inclined blank after upsetting; (22) placing the oblique blank between an upper flat anvil and a lower flat anvil that are arranged opposite to each other, so that the unnecessary side material of the head of the oblique blank faces the anvil surface, and pressing the side material of the oblique blank toward the required side by the upper flat anvil and the lower flat anvil; (23) placing the inclined blank rod portion pressed by the second tooling into the discharge cavity, repeating steps (21) to (22), repeatedly upsetting and pressing, guiding the metal at the blank head to flow away from the characteristic height H, thereby forming a blank head and obtaining an eccentric blank; (24) placing the eccentric blank between an upper anvil and a lower anvil that are arranged opposite to each other, and pressing the rod of the eccentric blank in the length direction by the extrusion force generated when the upper anvil and the lower anvil are closed, thereby shaping the rod, and finally obtaining an asymmetric structure blank; (25) The rough blank is then heated and die-forged to obtain a final forging of an aircraft landing gear outer tube having metal streamlines.

2. A forging method for increasing the life of an aircraft landing gear according to claim 1, characterized in that: The anvil surface and two side surfaces of the upper anvil and the lower anvil are both chamfered with a chamfer angle δ.

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