Integral forming method of Γ-shaped rib cylindrical part

Abstract

The present invention relates to the technical field of plastic processing of thin-walled parts, and discloses a method for integrally forming a Γ-shaped ribbed cylindrical part. First, a cylindrical part with nearly Γ-shaped ribs is prepared by shearing and spinning the cylindrical part blank, and gradient heating is applied to the ribs formed by shearing. Then, a flat rotating wheel is used to axially shape the Γ-shaped ribs, and finally a Γ-shaped ribbed cylindrical part is obtained. The present invention proposes a method for integrally forming a Γ-shaped ribbed cylindrical part. This forming method can not only significantly increase the rib height and inhibit cracking, but also facilitates the adjustment of process parameters, thereby realizing the regulation of the shape and size of the Γ-shaped ribbed cylindrical part. It uses local loading of two rotating wheels to put the material in a deformation state in which the shear deformation mode is the main mode and the upsetting deformation is the auxiliary mode, which significantly improves the rib height limit. By introducing a thermal field, the structure can undergo dislocation rearrangement and polygonization through dynamic recovery, thereby reducing deformation resistance and preventing rib cracking.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic processing of thin-walled parts, and in particular to an integral forming method of a Γ-shaped ribbed cylindrical part. Background Art

[0002] Γ-ribbed cylindrical components are thin-walled, ribbed cylindrical parts with complex cross-sectional shapes, consisting of a thin-walled cylinder and circumferential Γ-shaped reinforcing ribs. This complex cross-sectional shape effectively improves the strength and structural rigidity of cylindrical components while significantly reducing their mass, attracting widespread attention in fields such as aerospace and transportation. The characteristics and forming difficulties of these components primarily lie in the combination of a large-diameter cylinder (m-scale) and locally complex Γ-shaped ribs (cm-scale).

[0003] For this type of component, the main manufacturing methods currently used are mechanical processing or block forming followed by riveting / welding. Mechanical processing forms the required cross-sectional ribs by removing a large amount of material from the thick cylinder. This not only results in low material utilization and increased costs, but also cuts off metal streamlines, generates complex residual stresses, causes shape distortion and microcrack initiation, and restricts the shape accuracy and fatigue life of the component. Block forming followed by riveting / welding means first dividing the component into a thin-walled cylinder and ribs that can be spun or simply machined, and then connecting the formed cylinder and ribs together by riveting or welding. This forming method not only has problems such as many steps, a long process, and weight gain caused by rivets / welds, but also the residual stress at the connection point will greatly reduce the reliability and fatigue life of the component. With the continuous improvement of the requirements for lightweight, high performance, high reliability and long life of high-end equipment such as aerospace vehicles, new manufacturing processes need to be developed to achieve high-precision and high-performance integral forming of Γ-shaped ribbed cylindrical parts.

[0004] In the prior art, there are high-precision and high-performance integral forming methods for ribbed cylindrical parts. In the Chinese patent application document with application number 202111514553.5, a shear forming method for annular outer rib cylindrical parts is disclosed. This method uses axial loading of a shear wheel to shear and separate the material, and transfers it radially to form ribs. The formed ribs have the advantage of a large aspect ratio, but the cross-sectional shape is I-shaped. In the Chinese patent application document with application number 202310239465.1, a step-by-step shear forming method for T-ribbed cylindrical parts is disclosed. This method realizes the forming of complex T-section ribs through multi-directional collaborative loading of multiple wheels such as shear wheels, flow wheels and fractal wheels, but is not suitable for the forming of Γ-section ribs. The Chinese patent application document with application number 202110974901.0 discloses a method for rotary extrusion of a reinforced cylindrical shell. This method uses hot spinning to fill the material into the rib groove of the core mold, and improves the rib height limit and overall performance of the ribbed parts through multiple heat treatments. However, it is only suitable for the forming of ribs in I-sections, and has high requirements for the spinning core mold, making it difficult to extend to Γ-shaped ribbed cylindrical parts.

[0005] In summary, existing methods for integrally forming ribbed cylindrical components are limited to forming I- and T-shaped ribbed cylindrical components, and they also present problems such as uneven rib hardness distribution and susceptibility to cracking at the rib top. Therefore, it is necessary to propose a method for integrally forming Γ-shaped ribbed cylindrical components to broaden the application of such components. Summary of the Invention

[0006] In order to solve the above-mentioned technical problems existing in the prior art, the present invention provides an integral forming method for Γ-shaped ribbed cylindrical parts. This forming method can not only significantly increase the rib height and inhibit cracking, but also facilitate the adjustment of process parameters, thereby realizing the regulation of the shape and size of the Γ-shaped ribbed cylindrical parts.

[0007] To achieve the above object, the present invention provides a method for integrally forming a Γ-shaped ribbed cylindrical part, which comprises the following steps:

[0008] S1. Install the core mold on the mandrel of the spinning machine, clamp the positioning sleeve on the core mold, clamp the cylindrical blank on the core mold and position it using the positioning sleeve, install the shearing wheel and the horizontal wheel on the wheel frame of the spinning machine respectively, and assemble the flame spray gun on the spinning machine;

[0009] Among them, the initial wall thickness tb0 of the cylindrical blank satisfies the formula: Where D0 is the outer diameter of the cylindrical blank, d0 is the inner diameter of the cylindrical blank;

[0010] S2. Start the spinning machine, let the core shaft drive the cylindrical blank to rotate, and control the shearing wheel to cut to the preset depth a. p∈[0.2tb0,0.5tb0] feed f along the axial direction, f ≥ 30mm; then control the shearing wheel to withdraw in the radial direction, and use a flame spray gun to perform gradient heating on the rib formed by shearing during shearing and spinning. The forming temperature of the rib top is 100℃~800℃, and the forming temperature of the rib bottom is below 200℃ and lower than the forming temperature of the rib top, so as to prepare a nearly Γ-shaped ribbed cylindrical part;

[0011] S3, continuing the rotation state of the cylindrical blank and the heating state of the flame spray gun on the rib in step S2, controlling the flat-rotating wheel to feed axially according to the preset Γ-shaped rib height h until the wheel and the rib are no longer in contact, and then controlling the flat-rotating wheel to withdraw radially, finally preparing a Γ-shaped rib cylindrical part;

[0012] In the above steps, the parameters related to forming the Γ-shaped ribbed cylindrical part meet the following conditions:

[0013] t1<3.28a p ;

[0014] t2≤t1;

[0015]

[0016] d1≥d0;

[0017] dt1≥dt0;

[0018] L1 ≥ L0;

[0019]

[0020] Among them, t1 is the web width of the Γ-shaped rib, t2 is the flange width of the Γ-shaped rib, h is the rib height of the Γ-shaped rib, w is the rib width of the Γ-shaped rib, D1 is the outer diameter of the Γ-shaped rib cylindrical part, d1 is the inner diameter of the Γ-shaped rib cylindrical part, dt1 is the outer diameter of the positioning step in the Γ-shaped rib cylindrical part, L1 is the length of the Γ-shaped rib cylindrical part, tb1 is the wall thickness of the formed area of ​​the Γ-shaped rib cylindrical part, dt0 is the outer diameter of the positioning step in the cylindrical part blank, L0 is the length of the cylindrical part blank, a p is the preset shear depth and f is the axial feed distance.

[0021] As a further preferred technical solution of the present invention, the height of the positioning sleeve is less than or equal to the rib height of the Γ-shaped rib.

[0022] As a further preferred technical solution of the present invention, a positioning step is processed on the rear end portion of the cylindrical blank, and the height s of the positioning step is slightly smaller than the height of the groove on the positioning sleeve.

[0023] As a further preferred technical solution of the present invention, the shearing wheel includes an upper working surface and a lower working surface with an angle of 90° between them, and the upper and lower working surfaces are connected by a transition fillet with a radius of 0.5 to 1.5 mm; and / or, the installation angle of the shearing wheel relative to the core shaft is 45°.

[0024] As a further preferred technical solution of the present invention, the flat-rotating wheel includes a right working surface and a lower working surface with an angle of 90° between them, and the right and lower working surfaces are connected by a transition fillet with a radius of 1 to 5 mm; and / or, the installation angle of the flat-rotating wheel relative to the core shaft is 90°.

[0025] As a further preferred technical solution of the present invention, there are two shearing wheels and two flat wheels.

[0026] As a further preferred technical solution of the present invention, in step S2, the core shaft rotation speed is 30-90 rpm, and the shear wheel feed speed is 0.1-1.5 mm / s.

[0027] As a further preferred technical solution of the present invention, in step S3, the feeding speed of the flat-rotating wheel is 0.1 to 2.5 mm / s.

[0028] Compared with the existing technology, the beneficial effects achieved are:

[0029] 1. The present invention proposes a method for integrally forming a Γ-shaped ribbed cylindrical component. By locally loading the material with two rotating wheels, the material is subjected to a deformation state characterized by shear deformation as the primary mode and upsetting deformation as the secondary mode, significantly increasing the rib height limit.

[0030] 2. The present invention proposes a method for integrally forming a Γ-shaped ribbed cylindrical component. By introducing a thermal field, the structure can undergo dynamic recovery, causing dislocation rearrangement and polygonization, thereby reducing deformation resistance and preventing rib cracking.

[0031] 3. The present invention proposes a method for integrally forming a Γ-shaped ribbed cylindrical part, which includes a positioning sleeve, a shearing wheel, and a flat wheel. The method has a simple structure, is easy to install, and is convenient to operate, thereby improving the flexibility of the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 This is a schematic diagram of the integral forming process of a Γ-shaped ribbed cylindrical part;

[0034] Figure 2 It is a structural diagram of the positioning sleeve;

[0035] Figure 3 Schematic diagram of the structure of the shear wheel;

[0036] Figure 4 It is a structural diagram of the flat-rotating wheel;

[0037] Figure 5 It is a schematic diagram of the structural dimensions of the blank;

[0038] Figure 6 It is a schematic diagram of the structural dimensions of a Γ-shaped ribbed cylindrical part;

[0039] Figure 7 It is the Γ-shaped rib cylindrical member of Example 1;

[0040] Figure 8 The utility model is an I-shaped rib cylindrical part formed by an existing method.

[0041] In the figure: 1. Mandrel; 2. Mandrel; 3. Positioning sleeve; 4. Blank; 5. Shearing wheel; 6. I-shaped rib cylindrical part; 7. Near-Γ-shaped rib cylindrical part; 8. Flat wheel; 9. Γ-shaped rib cylindrical part; 10. Threaded hole; 11. Through hole; 12. Slot; 13. Upper working surface; 14. Lower working surface; 15. Right working surface; 16. Lower working surface; 17. Positioning step.

[0042] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Terms such as "upper," "lower," "left," "right," "center," and "one" used in the preferred embodiments are for ease of description and are not intended to limit the scope of the present invention. Changes or adjustments to these relative terms, without substantially altering the technical content, are also considered within the scope of the present invention.

[0044] Example 1:

[0045] like Figure 1 As shown, the embodiment provides a method for integrally forming a Γ-shaped rib cylindrical part, comprising the following steps:

[0046] S1. Install the mold and blank

[0047] Install the universal core mold 2 (inner diameter 201mm) on the core shaft 1 of the spinning machine, apply lubricant on the core mold 2, clamp the positioning sleeve 3 (inner diameter 201mm, height 30mm) on the universal core mold 2, clamp the cylindrical part blank 4 made of 6061 aluminum alloy (inner diameter 201mm, wall thickness 20mm, length 98mm) on the universal core mold 2 and the positioning sleeve 3, install the shearing wheel 5 (wheel corner radius 0.5mm) and the flat wheel 8 (wheel corner radius 2mm) on the wheel frame of the spinning machine respectively, and assemble a flame spray gun (one) on the spinning machine.

[0048] In step S1, the structure of the positioning sleeve 3 is as follows Figure 2 As shown, the reserved threaded hole 10 is used to connect the petaled positioning sleeve to increase the total height of the positioning sleeve and improve the rib height limit of the Γ-shaped rib proposed by the present invention; the through hole 11 is used to fix the positioning sleeve 3 to the core mold 2; the slot 12 is used to fix the cylindrical blank 4 to the positioning sleeve 3. The structure of the cylindrical blank 4 is as shown Figure 3 As shown, the positioning step 17 is used to fix the cylindrical blank 4 to the positioning sleeve 3, D0 is the outer diameter of the cylindrical part, d0 is the inner diameter of the cylindrical part, L0 is the length of the cylindrical part, dt0 is the outer diameter of the positioning step, s is the depth of the positioning step, and c is the length of the positioning step.

[0049] S2. Shearing and forming I-shaped rib tube → Shearing and forming nearly Γ-shaped rib tube → Shearing wheel exit

[0050] Start the spinning machine, and let the core shaft 2 drive the 6061 aluminum alloy cylindrical blank 4 to rotate (rotation speed 60rpm), control the shearing wheel 5 to feed 80mm in the axial direction according to the process parameters of shear depth 6mm and feed speed 0.5mm / s, and then control the shearing wheel to withdraw in the radial direction according to the process parameters of feed speed 0.5mm / s. At the same time, use a flame spray gun to adopt gradient heating for the rib, that is, the heating temperature of the top of the rib is high (the temperature of the top of the rib is about 250℃) and the heating temperature of the bottom of the rib is low (the temperature of the bottom of the rib is about 100℃). The I-shaped rib is formed by shearing and then heated by gradient heating. At this time, the top of the I-shaped rib will undergo dynamic recovery, reducing the deformation resistance and stiffness of the material, while the bottom of the I-shaped rib is mainly affected by work hardening, with a low degree of dynamic recovery and a large stiffness of the rib. Therefore, under the axial loading of the wheel, the rib will tilt toward the free surface side, thereby preparing a nearly Γ-shaped rib cylindrical part 7.

[0051] In step S2, the structure of the shearing wheel 5 is as follows: Figure 4 As shown, the shear wheel includes an upper working surface 13 and a lower working surface 14 with an angle of 90° between them. The upper working surface 13 and the lower working surface 14 are connected by a transition fillet with a radius of 0.5 mm. The installation angle of the shear wheel relative to the core shaft is 45°.

[0052] In step S2, the flame spray gun is located on the side of the cylindrical part close to the core shaft 2, the flame is aimed at the top of the rib, and gradually moves outward as the rib grows. The temperature of the rib is monitored in real time by an infrared thermal imager to ensure that the rib temperature is within a preset state and range.

[0053] It is worth noting that in this processing process, the cylindrical blank 4 is first sheared to form an I-rib cylindrical part 6, and then when the axial feed distance of the shearing wheel 5 is about 30 mm, the cylindrical blank 4 is transformed from an I-rib cylindrical part 6 to a nearly Γ-rib cylindrical part 7.

[0054] S3, horizontal rotary wheel feed → axial shaping to form Γ-shaped rib cylinder → horizontal rotary wheel exit → unloading

[0055] Continuing with the rotation of the cylindrical blank and the flame spray gun heating the ribs in step S2, the horizontal rotating wheel 8 is controlled to advance 100 mm axially, according to the process parameters of a Γ-rib height of 30 mm and a feed rate of 0.5 mm / s. The horizontal rotating wheel is then controlled to withdraw radially, also at a feed rate of 0.5 mm / s, to form a Γ-rib cylindrical part 9. Finally, the Γ-rib cylindrical part 9 is removed from the spinning machine and subjected to further machining and heat treatment to further control the shape, size, and overall performance of the Γ-rib cylindrical part.

[0056] In step S3, the structure of the flat-rotating wheel 8 is as follows: Figure 5 As shown, the flat-rotating wheel includes a right working surface 15 and a lower working surface 16 with an angle of 90° between them. The right working surface 15 and the lower working surface 16 are connected by a transition fillet with a radius of 2 mm. The installation angle of the flat-rotating wheel relative to the core shaft is 90°.

[0057] The structure of the finally formed Γ-shaped rib cylindrical member 9 is as follows Figure 6 As shown, D1 is the outer diameter of the cylindrical part, d1 is the inner diameter of the cylindrical part, L1 is the length of the cylindrical part, dt0 is the outer diameter of the positioning step, h is the rib height of the Γ-shaped rib, w is the rib width of the Γ-shaped rib, t1 is the web width of the Γ-shaped rib, and t2 is the wing width of the Γ-shaped rib.

[0058] like Figure 7 As shown, it can be seen that the surface quality of the Γ-shaped rib of the finally formed Γ-shaped rib cylindrical part is good, without macro cracks and defects.

[0059] Comparative Example 1:

[0060] As a control experiment for Example 1, based on the preparation method of Example 1, the gradient heating operation in step 2 was omitted, and the same tooling and forming parameters were used to process the same blank. An I-shaped rib cylindrical part was formed by axial shearing in step 2 (omitting the gradient heating). However, compared with Example 1, the total amount of material deformation and axial feed distance required for the Γ-shaped rib cylindrical part were larger, and cracking occurred when the axial feed distance was about 80 mm. Figure 8 As shown. Furthermore, if an I-shaped rib cylindrical part is formed at a smaller axial feed distance (e.g., 54 mm) and then axial shaping is continued according to step 3 of Example 1, the rib top will crack due to the excessive total deformation, and ultimately, a Γ-shaped rib cylindrical part cannot be formed. In summary, the gradient heating and shearing forming method for Γ-shaped rib cylindrical parts proposed in the present invention can achieve the integral forming of Γ-shaped rib cylindrical parts and improve the forming limit of the Γ-shaped rib.

[0061] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to the embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is limited only by the appended claims.

Claims

1. A method for integrally forming a Γ-shaped ribbed cylindrical part, characterized in that: The following steps are involved: S1. Install the core mold on the mandrel of the spinning machine, clamp the positioning sleeve on the core mold, clamp the cylindrical blank on the core mold and position it using the positioning sleeve, install the shearing wheel and the horizontal wheel on the wheel frame of the spinning machine respectively, and assemble the flame spray gun on the spinning machine; Among them, the initial wall thickness tb0 of the cylindrical blank satisfies the formula: , where D0 is the outer diameter of the cylindrical blank and d0 is the inner diameter of the cylindrical blank; S2. Start the spinning machine, let the core shaft drive the cylindrical blank to rotate, and control the shearing wheel to cut to the preset depth a. p ∈[0.2tb0,0.5tb0] is fed in the axial direction, and then the shearing wheel is controlled to withdraw in the radial direction. During the shearing and spinning, the rib formed by shearing is heated in a gradient manner using a flame spray gun. The forming temperature of the rib top is 100℃~800℃, and the forming temperature of the rib bottom is below 200℃ and lower than the forming temperature of the rib top, thereby forming a nearly Γ-shaped ribbed cylindrical part. Among them, the axial feed distance f of the shear wheel is ≥30mm; S3, continuing the rotation state of the cylindrical blank and the heating state of the flame spray gun on the rib in step S2, controlling the flat-rotating wheel to feed axially according to the preset Γ-shaped rib height h until the wheel and the rib are no longer in contact, and then controlling the flat-rotating wheel to withdraw radially, finally preparing a Γ-shaped rib cylindrical part; In the above steps, the parameters related to forming the Γ-shaped ribbed cylindrical part meet the following conditions: ； ； ； ； ； ； ； ； Among them, t1 is the web width of the Γ-shaped rib, t2 is the flange width of the Γ-shaped rib, h is the rib height of the Γ-shaped rib, w is the rib width of the Γ-shaped rib, D1 is the outer diameter of the Γ-shaped rib cylindrical part, d1 is the inner diameter of the Γ-shaped rib cylindrical part, dt1 is the outer diameter of the positioning step in the Γ-shaped rib cylindrical part, L1 is the length of the Γ-shaped rib cylindrical part, tb1 is the wall thickness of the formed area of ​​the Γ-shaped rib cylindrical part, dt0 is the outer diameter of the positioning step in the cylindrical part blank, L0 is the length of the cylindrical part blank, a p is the preset shearing depth and f is the axial shearing feed distance.

2. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: The height of the positioning sleeve is less than or equal to the rib height of the Γ-shaped rib.

3. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: A positioning step is processed on the rear end portion of the cylindrical blank, and the height s of the positioning step is slightly smaller than the height of the clamping groove on the positioning sleeve.

4. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: The shearing wheel includes an upper working surface and a lower working surface with an angle of 90° between them, and the upper and lower working surfaces are connected by a transition fillet with a radius of 0.5-1.5 mm; and / or, the installation angle of the shearing wheel relative to the core shaft is 45°.

5. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: The flat-rotating wheel includes a right working surface and a lower working surface with an angle of 90° between them. The right and lower working surfaces are connected by a transition fillet with a radius of 1-5 mm; and / or, the installation angle of the flat-rotating wheel relative to the core shaft is 90°.

6. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: The number of the shearing wheels and the flat wheels are both two.

7. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: In step S2, the spindle speed is 30-90 rpm, and the shear wheel feed speed is 0.1-1.5 mm / s.

8. The integral forming method of a Γ-shaped rib cylindrical part according to claim 1, characterized in that: In step S3, the feeding speed of the flat-rotating wheel is 0.1-2.5 mm / s.

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