Orifice deburring reinforcement forming tool and method

Abstract

The present application relates to a kind of orifice chamfering reinforcement forming tool and method thereof.It includes support seat, conical surface pressure head, roller and cage;The orifice chamfering reinforcement forming tool is used to roll the orifice edge into target orifice chamfer;Support seat lower part is support platform, and support shaft is vertically extended on support platform;Conical surface pressure head is rotary body, and central shaft hole is opened, and the lower end of the conical surface pressure head forms outer conical surface, and the conical surface angle of outer conical surface is identical with the chamfer angle of target orifice chamfer;Ring groove is opened on the outer conical surface, and cage and multiple rollers are arranged in the ring groove, and the spacing between the roller is kept under the limitation of the cage, while rolling in the ring groove in ring direction.The beneficial residual compressive stress is generated in the surface layer and subsurface of orifice chamfer after rolling extrusion, and the hardness of metal surface, the strength of material and surface finish are improved.

Description

Technical Field

[0001] This invention relates to the field of fatigue-resistant manufacturing technology for metal parts, and specifically to a tool and method for strengthening the beveling of bore openings. Background Technology

[0002] Currently, many parts in helicopter structures are assembled using fasteners with load-bearing holes. However, due to stress concentration around these holes, they are subjected to combined stress, strain, and impact loads during aircraft service. This can lead to premature fatigue cracking on the hole walls, severely reducing the fatigue life of structural components. Fatigue failure has become a major failure mode for aircraft structural components, and its danger and destructiveness are extremely high due to the lack of obvious plastic deformation and accident signs beforehand. In particular, critical structural components of the rotor system are subjected to complex high-frequency vibrations and alternating loads, making them prone to fatigue cracks or even fractures at the edge of the fastener hole, resulting in loss of control functions. Load-bearing holes are subject to multi-field thermo-mechanical coupling during processing, easily generating multi-scale errors and defects in geometry and surface properties. Fasteners on load-bearing structural components of aircraft are stress concentration points with relatively weak fatigue strength; failure of the hole structure often leads to airframe failure. Therefore, research and application of fatigue-resistant strengthening technology for critical load-bearing holes is an urgent problem to be solved and a key research direction in helicopter fatigue-resistant manufacturing.

[0003] Fatigue-resistant manufacturing technology refers to manufacturing techniques that improve the fatigue life of parts by altering the material's microstructure and stress distribution during the manufacturing process without changing the material or cross-sectional dimensions. In current production practice, various methods exist for fatigue-resistant manufacturing, which can be broadly categorized as mechanical, physical, chemical, and high-energy beam methods. The prominent feature of mechanical methods is the use of cold deformation technology to create a work-hardened layer on the surface of the metal material and introduce high residual compressive stress. This reduces crack nucleation under fatigue stress and inhibits early crack propagation, while simultaneously improving surface finish. This significantly enhances the mechanical parts' resistance to fatigue fracture and stress corrosion cracking. Key process methods include rolling, extrusion, shot peening, and interference fit.

[0004] Currently, the main methods for strengthening load-bearing hole structures include hole extrusion strengthening, hole rolling strengthening, and ultrasonic vibration rolling strengthening. However, due to limitations in the process methods, the strengthening is mainly concentrated on the inner wall of the load-bearing hole, and is not applicable to the chamfered areas on both sides of the hole opening. Summary of the Invention

[0005] The purpose of this invention is to provide a tool and processing method for strengthening the chamfering of load-bearing holes in aerospace materials such as aluminum alloys and titanium alloys, which significantly improves the hardness of the metal surface, the strength of the material, and the surface finish, thereby improving fatigue resistance and stress corrosion resistance.

[0006] The technical solution of the present invention:

[0007] A tool for beveling and reinforcing an orifice is provided, comprising a support base, a conical pressure head 4, a roller 5, and a retainer 6; the tool is used to roll the edge of an orifice into a target beveled shape.

[0008] The lower part of the support base is a support platform 3, and a support shaft 2 extends vertically from the support platform;

[0009] The conical indenter is a rotating body with a central shaft hole. The lower end of the conical indenter forms an outer conical surface, and the conical angle of the outer conical surface is the same as the chamfer angle of the target hole opening. The outer diameter of the outer conical surface is larger than the outer diameter of the target hole opening chamfer.

[0010] An annular groove is formed on the outer conical surface. A retainer 6 and a plurality of rollers are arranged in the annular groove. The rollers maintain the spacing between the rollers under the constraint of the retainer 6, and roll circumferentially in the annular groove at the same time.

[0011] The support shaft and the central shaft hole of the conical indenter are in a sliding friction fit, which allows the conical indenter to rotate relative to the support shaft.

[0012] Furthermore, the material hardness of the roller 5 is higher than that of the orifice.

[0013] Furthermore, multiple rollers 5 are evenly distributed circumferentially.

[0014] Furthermore, the conical indenter is a component, and the conical indenter in the component has different outer conical surface angles. Different outer conical surface angles correspond to different angle requirements for the chamfering angle of the orifice.

[0015] A method for strengthening the beveling edge of the orifice based on the above-mentioned orifice beveling strengthening forming tool is also provided.

[0016] Step 1: Preliminary processing

[0017] The primary bore chamfer is machined by cutting process. During the machining process, it is ensured that the axial length of the primary bore chamfer is the same as the axial length of the target bore chamfer, and the taper angle of the primary bore chamfer is greater than the taper angle of the target bore chamfer.

[0018] Step 2, Pre-spinning judgment

[0019] The maximum compression J of the chamfered edge after cutting is determined, and the maximum compression J is obtained by the following formula:

[0020]

[0021] Where J is a preset constant in mm; A is the axial length of the primary and target bore chamfers in mm; ov is the tapered width of the primary bore chamfer; C is the tapered angle of the target bore chamfer; X is the angle difference between the tapered angle of the target bore chamfer and the tapered angle of the primary bore chamfer; and X+C is the tapered angle of the primary bore chamfer.

[0022] Determine whether the maximum compression J is within the compression range of the matrix material of the hole. If it is, continue to step 3; otherwise, return to step 1.

[0023] Step 3: Spinning and beveling

[0024] The support shaft of the support base passes through the central shaft hole, and the support platform is supported at the lower end of the hole. The roller presses against the chamfer of the primary hole, causing the conical pressure head 4 to rotate M, which in turn drives the roller to roll. An axial thrust F is applied to the conical pressure head 4, and the roller rolls against the chamfer of the primary hole. The axial feed of the conical pressure head is monitored in real time, and the rotation and axial feed of the conical pressure head are stopped when the axial feed H is reached.

[0025] feed rate

[0026] Furthermore, the substrate material of the hole 1 is ultra-high strength steel, and the value of J is 0.1 to 0.2 mm.

[0027] Furthermore, the base material of the hole is alloy structural steel, and J is taken as 0.1 to 0.3 mm.

[0028] Furthermore, the base material of the hole is aluminum alloy, and J is 0.2 to 0.3 mm.

[0029] Furthermore, the base material of the pore is titanium alloy, and J is 0.1 to 0.3 mm.

[0030] Furthermore, the base material of the hole is stainless steel, and J is 0.2 to 0.3 mm.

[0031] Furthermore, at the beginning of step 3, lubricant is applied to the conical surface of the primary orifice bevel.

[0032] Furthermore, the rotational speed of the conical indenter is 1-2 revolutions / second, and the axial feed speed of the conical indenter is 0.05-0.08 mm / s.

[0033] The beneficial effects of this invention are as follows: By applying force to the surface of a metal part using a tool with a higher strength and hardness than the metal part itself, and utilizing the self-centering property of the taper, under the combined action of axial pressure and rotational torque (rotational action), the tool of this invention causes the chamfer of the bearing hole to undergo a "rolling dough" forced movement. The surface material of the metal part undergoes forced flow and elastoplastic deformation, resulting in grain breakage and refinement, and an increase in dislocation density. This generates beneficial residual compressive stress on the surface and subsurface layers of the chamfered hole after rolling and extrusion, thereby improving the hardness of the metal surface, the strength of the material, and the surface finish, and thus improving fatigue resistance and stress corrosion resistance. Attached Figure Description

[0034] When read in conjunction with the accompanying drawings, the exemplary embodiments, preferred modes of use, other objects, and description thereof will be best understood by referring to the following detailed description of examples of the invention, wherein:

[0035] Figure 1 This is a schematic diagram illustrating the structure and use of the present invention;

[0036] Figure 2 A cross-sectional view showing the structure and use of the present invention;

[0037] Figure 3 Exploded view of the support platform, conical indenter, rollers, and cage;

[0038] Figure 4 This is a schematic diagram of the support structure.

[0039] Figure 5 A diagram illustrating the principles of various parameters in the rolling process;

[0040] Among them, 1-the base of the hole, 2-the support shaft, 3-the support platform, 4-the conical pressure head, 5-the roller, and 6-the cage. Detailed Implementation

[0041] The disclosed examples will be described more fully with reference to the accompanying drawings, in which some (but not all) of the disclosed examples are shown. In fact, many different examples may be described, and these examples should not be construed as limited to those set forth herein. Rather, these examples are described so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0042] See the example. Figure 1 A tool for strengthening and forming a beveled opening is provided, comprising a support base, a conical pressure head 4, a roller 5, and a retainer 6; the tool is used to roll the edge of a hole into a target beveled opening.

[0043] The lower part of the support base is a support platform 3, and a support shaft 2 extends vertically from the support platform;

[0044] The conical indenter is a rotating body with a central shaft hole. The lower end of the conical indenter forms an outer conical surface, and the conical angle of the outer conical surface is the same as the chamfer angle of the target hole opening. The outer diameter of the outer conical surface is larger than the outer diameter of the target hole opening chamfer.

[0045] An annular groove is formed on the outer conical surface. A retainer 6 and a plurality of rollers are arranged in the annular groove. The rollers maintain the spacing between the rollers under the constraint of the retainer 6, and roll circumferentially in the annular groove at the same time.

[0046] The support shaft and the central shaft hole of the conical indenter are in a sliding friction fit, which allows the conical indenter to rotate relative to the support shaft.

[0047] Furthermore, the material hardness of the roller 5 is higher than that of the orifice.

[0048] Furthermore, multiple rollers 5 are evenly distributed circumferentially.

[0049] Furthermore, the conical indenter is a component, and the conical indenter in the component has different outer conical surface angles. Different outer conical surface angles correspond to different angle requirements for the chamfering angle of the orifice.

[0050] A method for strengthening the beveling edge of the orifice based on the above-mentioned orifice beveling strengthening forming tool is also provided.

[0051] Step 1: Preliminary processing

[0052] The primary bore chamfer is machined by cutting process. During the machining process, it is ensured that the axial length of the primary bore chamfer is the same as the axial length of the target bore chamfer, and the taper angle of the primary bore chamfer is greater than the taper angle of the target bore chamfer.

[0053] Step 2, Pre-spinning judgment

[0054] The maximum compression J of the chamfered edge after cutting is determined, and the maximum compression J is obtained by the following formula:

[0055]

[0056] Where J is a preset constant in mm; A is the axial length of the primary and target bore chamfers in mm; ov is the tapered width of the primary bore chamfer; C is the tapered angle of the target bore chamfer; X is the angle difference between the tapered angle of the target bore chamfer and the tapered angle of the primary bore chamfer; and X+C is the tapered angle of the primary bore chamfer.

[0057] Determine whether the maximum compression J is within the compression range of the matrix material of the hole. If it is, continue to step 3; otherwise, return to step 1.

[0058] Step 3: Spinning and beveling

[0059] The support shaft of the support base passes through the central shaft hole, and the support platform is supported at the lower end of the hole. The roller presses against the chamfer of the primary hole, causing the conical pressure head 4 to rotate M, which in turn drives the roller to roll. An axial thrust F is applied to the conical pressure head 4, and the roller rolls against the chamfer of the primary hole. The axial feed of the conical pressure head is monitored in real time, and the rotation and axial feed of the conical pressure head are stopped when the axial feed H is reached.

[0060] feed rate

[0061] The substrate material of the hole is ultra-high strength steel, and the value of J is 0.1 to 0.2 mm.

[0062] At the beginning of step 3, apply lubricant to the tapered surface of the primary bore bevel.

[0063] The rotational speed of the conical indenter is 1-2 revolutions / s, and the axial feed speed of the conical indenter is 0.05-0.08 mm / s.

[0064] The various examples of systems, apparatuses, and methods disclosed herein include a wide range of components, features, and functions. It should be understood that the various examples of systems, apparatuses, and methods disclosed herein may include any of the components, features, and functions of any of the other examples of systems, apparatuses, and methods disclosed herein in any combination or sub-combination, and all such possibilities are intended to fall within the scope of the invention.

[0065] Descriptions of various advantageous arrangements have been shown for illustrative and descriptive purposes, but such descriptions are not intended to be exclusive or limited to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different advantageous examples may describe different advantages compared to other advantageous examples. One or more examples have been selected and described in order to best illustrate the principles and practical application of the examples, and to enable those skilled in the art to understand that this disclosure contains various examples with various modifications suitable for the particular intended use.

Claims

1. A tool for strengthening and shaping by beveling the opening, characterized in that: It includes a support base, a conical pressure head, rollers, and a retainer; the orifice chamfering and strengthening forming tool is used to roll the orifice edge into the target orifice chamfer; The lower part of the support base is a support platform, and a support shaft extends vertically from the support platform; The conical indenter is a rotating body with a central shaft hole. The lower end of the conical indenter forms an outer conical surface, and the conical angle of the outer conical surface is the same as the chamfer angle of the target hole opening. The outer diameter of the outer conical surface is larger than the outer diameter of the target hole opening chamfer. An annular groove is formed on the outer conical surface. A retainer and a plurality of rollers are arranged in the annular groove. The rollers maintain the spacing between the rollers under the constraint of the retainer, and roll circumferentially in the annular groove at the same time. The support shaft and the central shaft hole of the conical indenter are in a sliding friction fit, which allows the conical indenter to rotate relative to the support shaft. The roller is made of a material with a higher hardness than the orifice. Multiple rollers are evenly distributed circumferentially; The conical indenter is a component, and the conical indenters in the component have different outer conical angles.

2. A method for strengthening the beveling edge of an orifice, using the beveling edge strengthening forming tool described in claim 1, characterized in that, Includes the following steps: Step 1: Preliminary processing The primary bore chamfer is machined by cutting process. During the machining process, it is ensured that the axial length of the primary bore chamfer is the same as the axial length of the target bore chamfer, and the taper angle of the primary bore chamfer is greater than the taper angle of the target bore chamfer. Step 2, Pre-spinning judgment The maximum compression J of the chamfered edge after cutting is determined, and the maximum compression J is obtained by the following formula: Where J is a preset constant in mm; A is the axial length of the primary and target bore chamfers in mm; ov is the tapered width of the primary bore chamfer; C is the tapered angle of the target bore chamfer; X is the angle difference between the tapered angle of the target bore chamfer and the tapered angle of the primary bore chamfer; and X+C is the tapered angle of the primary bore chamfer. Determine whether the maximum compression J is within the compression range of the matrix material of the hole. If it is, continue to step 3; otherwise, return to step 1. Step 3: Spinning and beveling The support shaft of the support base passes through the central shaft hole, and the support platform is supported at the lower end of the hole. The roller presses against the chamfer of the primary hole, causing the conical pressure head 4 to rotate M, which in turn drives the roller to roll. An axial thrust F is applied to the conical pressure head 4, and the roller rolls against the chamfer of the primary hole. The axial feed of the conical pressure head is monitored in real time, and the rotation and axial feed of the conical pressure head are stopped when the axial feed H is reached. feed rate 3. The orifice beveling strengthening method according to claim 2, characterized in that: The base material of the hole is ultra-high strength steel, and J is 0.1 to 0.2 mm.

4. The orifice beveling strengthening method according to claim 2, characterized in that: The base material of the hole is alloy structural steel, and J is 0.1 to 0.3 mm.

5. The orifice beveling strengthening method according to claim 2, characterized in that: The base material of the hole is aluminum alloy, and J is 0.2 to 0.3 mm.

6. The orifice beveling reinforcement method according to claim 2, characterized in that: The base material of the hole is titanium alloy, and J is 0.1 to 0.3 mm.

7. The orifice beveling strengthening method according to claim 2, characterized in that: The base material of the hole is stainless steel, and J is 0.2 to 0.3 mm.

Images