Method for improving rib thickness uniformity of high-rib thin-wall cylindrical component formed through local shearing

Abstract

The invention relates to the technical field of metal plastic processing, and discloses a method for improving thickness uniformity of a rib part of a high-rib thin-wall cylindrical component formed by local shearing, which comprises the following steps of: clamping a cylinder blank to a mandrel of a spinning machine tool by applying radial constraining force; a flowing spinning roller of a double-conical-surface structure is selected for flowing spinning, the flowing spinning roller is controlled to conduct one-pass overall thinning on a barrel body of the barrel blank from a forming working face of the flowing spinning roller, then second-pass local thinning is conducted on part of barrel sections, and a step-shaped forming face is formed at the tail end of the second-pass local thinning barrel section; and a shearing spinning roller is selected to conduct local shearing forming, the bottom of the forming face serves as a shearing starting position, the shearing spinning roller is controlled to conduct axial shearing feeding on the non-thinned barrel section, and the annular outer rib barrel-shaped piece is obtained. The method is simple, compared with the prior art, the process device is further simplified, the thickness uniformity of the high ribs is improved, and the requirements of a multi-rib structural component and a variable-wall-thickness component can be met.

Description

Technical Field

[0001] The invention relates to the technical field of metal plastic processing, and in particular to a method for improving the thickness uniformity of the ribs of a locally shear-formed high-rib thin-walled cylindrical component. Background Art

[0002] With the rapid development of aerospace and advanced weapons and equipment, the demand for ribbed structural parts is also increasing. Among them, for thin-walled annular outer ribbed cylindrical parts, due to the particularity of their own structure, the existing process has great limitations in forming thin-walled annular outer ribbed cylindrical parts.

[0003] The Chinese patent with patent number CN202111514553.5 discloses a shear forming method for annular outer rib cylindrical parts. The invention is based on the characteristics of local loading progressive (spinning) forming. The central axis of the shearing wheel is arranged at a certain angle to the axis of the core shaft, making full use of shear deformation to promote the flow of materials in the radial and axial directions. However, with the increase of the axial feed length, the wall thickness of the ribs is unevenly distributed. In the Chinese patent with patent number 202211614009.2, a processing method for large thin-walled flanges is disclosed. In this method, an annular back pressure die is additionally provided on the basis of the shear forming process. This method requires the shaping of the formed rib structure through the joint extrusion of the back pressure die and the spinning wheel. Due to the insufficient flexibility of the back pressure die, it is difficult to meet the needs of forming multiple rib components and variable wall thickness cylindrical wall components.

[0004] The Chinese patent number CN202111514518.3 discloses a method for heat-assisted multi-rotor spinning to form high-ribbed thin-walled cylindrical parts. This method uses an external heat source to soften the blank, then uses a flow wheel to thin the cylindrical blank in sections; finally, a shear wheel is used to form high-ribbed thin-walled components. However, the softening of the material reduces the reverse bending effect brought by the new surface of the rib structure, which makes the rib structure prone to bending during the forming process.

[0005] In summary, the existing plastic forming process of cylindrical parts has certain limitations. Under the premise of ensuring uniform distribution of rib width, how to simplify the process equipment and simultaneously meet the forming of multiple conditions and multiple working conditions is an urgent problem to be solved. To this end, this patent proposes to first thin the cylindrical blank as a whole, and then thin it in sections, making full use of the forming angle exit angle left by the flow wheel on the blank, and using the material work hardening effect to reduce the fluctuation range of the main shear surface angle during the local shear forming process, thereby achieving the control of the uneven distribution of rib wall thickness. Summary of the invention

[0006] In view of the above-mentioned technical problems, the present invention provides a method for improving the uniformity of the rib thickness of locally shear-formed high-rib thin-walled cylindrical components. The method is based on the local shear forming and flow spinning process of annular outer rib cylindrical parts. According to the characteristics of work hardening of materials during deformation, active local loading deformation is combined with passive material hardening. The distribution of rib width is improved while simplifying the process equipment, thereby achieving an improvement in the uniformity of high rib thickness.

[0007] To achieve the above object, the present invention provides a method for improving the uniformity of rib thickness distribution of a locally shear-formed high-rib thin-walled cylindrical component, which comprises the following steps:

[0008] S1. Install the tube blank:

[0009] Clamp the tube blank onto the mandrel of the spinning machine, and start the spinning machine to drive the tube blank to rotate synchronously with the mandrel;

[0010] S2, Flow Spinning:

[0011] A flow spinning wheel with a double-conical surface structure is selected for flow spinning. The flow spinning wheel includes a forming working surface and an exiting working surface connected by a circular arc working surface transition. The feed angle of the forming working surface is α p , 15 degrees <α p <45 degrees; the flow wheel is controlled to firstly perform one-pass overall thinning on the cylindrical blank, and then perform two-pass local thinning on the cylindrical blank, and a step-shaped forming surface is formed at the thinning feeding end of the two-pass local thinning section, and the angle α1 between the forming surface and the axial direction of the cylindrical blank is equal to α p ;

[0012] S3, Shearing Forming:

[0013] A shearing wheel is selected for local shearing and forming. The angle between the upper shearing working surface and the lower shearing working surface of the shearing wheel is 90 degrees. The lower shearing working surface is fitted to the outer surface of the second-pass locally thinned cylinder segment, and the bottom of the step of the forming surface in step S2 is used as the shearing starting position. The shearing wheel is controlled to perform axial shearing and feeding on the single-thinned cylinder segment. The shearing feed direction is consistent with the thinning feed direction until the shearing feed distance reaches a preset value to prepare a high-rib thin-walled cylindrical part.

[0014] As a further preferred technical solution of the present invention, the overall thinning amount in one pass in step S2 is 20% to 30% of the thickness of the tube blank, the total thinning amount of the two passes of local thinning of the tube section after two passes of thinning (the sum of the thinning amount in the first pass and the second pass) is 40% to 60% of the thickness of the tube blank, and the shearing feed distance in step S3 is 3 to 8 times the total thinning amount. Further preferably, the overall thinning amount of the tube blank in the first pass is 20% of the thickness of the tube blank, the total thinning amount of the local area in two passes is 60% of the thickness of the tube blank, and the shearing feed distance is 6 to 7 times the thinning amount.

[0015] As a further preferred technical solution of the present invention, in step S2, the flow wheel first thins the tube blank as a whole, and then thins it locally by segmented thinning. Along the local thinning feed direction, a forming surface is formed at the end of each locally thinned tube segment. Through step S3, annular external ribs can be formed at the thinning feed end of each locally thinned tube segment.

[0016] As a further preferred technical solution of the present invention, the exit angle of the exit working surface of the flow wheel is β p , β p If the angle is less than 30 degrees, the flow roller is controlled to feed in the opposite direction of the thinning feed in step S2 so as to reshape the root of the annular outer rib formed in step S3 by exiting the working surface.

[0017] As a further preferred technical solution of the present invention, 10 degrees < β p <30 degrees.

[0018] As a further preferred technical solution of the present invention, there are multiple flow wheels, which are evenly arranged around the tube blank in a circumferential direction. The multiple flow wheels operate synchronously during the flow spinning process to act on the tube blank at the same time.

[0019] The method of improving the uniformity of the thickness of the ribs of a locally sheared high-rib thin-walled cylindrical component of the present invention adopts the above technical solution, and can achieve the following beneficial effects:

[0020] 1) The processing method provided by the present invention applies radial constraints to the cylindrical part, and then uses a flow roller to first perform overall thinning on the cylindrical blank, and then performs secondary thinning at a preset special position, so as to form a step-shaped forming surface between the single-thinned barrel section and the secondary-thinned barrel section of the cylindrical blank, and then uses the bottom of the forming surface as the shearing starting position to feed shear toward the single-thinned barrel section through the shearing roller, thereby forming a high-rib structure with uniform rib thickness distribution. In addition, since the cylindrical part is first flow-spun before shearing and forming, the cylindrical part blank is hardened as a whole, and it is not easy to produce the defect of diameter expansion in the process of forming the high-rib structure; when forming a multi-rib structure, the exit surface after flow spinning can be fully utilized to reduce the problem of the widest root of the rib in the local shearing forming process.

[0021] 2) The method of the present invention is simple and further simplifies the process device compared with the prior art. It not only improves the uniformity of high-rib thickness, but also meets the needs of multi-rib structural components and variable wall thickness components. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Figure 1 and Figure 2 It is a schematic diagram of the state in which the flow spinning wheel of the present invention performs flow spinning on the tube blank.

[0024] Figure 3 It is a schematic diagram of the state in which the shearing wheel of the present invention performs local shearing and forming on the tube blank.

[0025] Figure 4 It is a schematic diagram of the structure of the flow wheel of the present invention;

[0026] Figure 5 It is a partial enlarged view of the flow wheel of the present invention;

[0027] Figure 6 It is a structural schematic diagram of the shearing wheel of the present invention;

[0028] Figure 7 The annular outer rib cylindrical parts are obtained by processing the cylindrical blanks in Example 1 and Comparative Example 1 respectively, wherein a is the cross section of the second high rib structure; b is the cross section of the first high rib structure.

[0029] Figure 8 This is the influence diagram of overall spinning on local shear forming components. It can be clearly seen that after overall thinning, the work hardening effect of the cylindrical blank plays an important role in improving the rib thickness.

[0030] In the figure: 1, tube blank, 2, mandrel, 3, flow wheel, 301, forming working surface, 302, arc working surface, 303, exiting working surface, 4, shearing wheel, 401, upper shearing working surface, 402, lower shearing working surface, 5, forming surface.

[0031] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The terms such as "upper", "lower", "left", "right", "middle" and "one" cited in the embodiments are only for the convenience of description, and are not used to limit the scope of the present invention. The change or adjustment of the relative relationship shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0033] Example 1

[0034] like Figure 1-3 The present embodiment provides a method for improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component, which specifically includes the following steps:

[0035] S1. Install the tube blank:

[0036] The tube blank 1 with a wall thickness of t=12mm is clamped to the mandrel 2 of the spinning machine, and the spinning machine is started to drive the tube blank 1 to rotate synchronously with the mandrel 2. The tube blank can be fixed by radial constraint through an annular back pressure die, or other clamps can be used to fix the tube blank, which is not limited here, as long as the tube blank 1 and the mandrel 2 can be relatively fixed and remain stable during the subsequent spinning process.

[0037] S2, Flow Spinning:

[0038] Select the flow wheel 3 with double cone structure (see Figure 4 and 5 As shown in FIG. 1 , the flow spinning is performed, the flow spinning wheel 3 includes a forming working surface 301 and an exiting working surface 303 connected by a transition of a circular arc working surface 302, and the feed angle α of the forming working surface p = 30 degrees; control the radial direction of the flow wheel 3 to be perpendicular to the axial direction of the tube blank 1, firstly, the cylindrical blank is thinned as a whole (see Figure 1 As shown), the thinning amount is 2mm, and after pressing, the axial thinning feed is started until the wall thickness of the tube blank 1 becomes 10mm as a whole; then the thinned tube blank 1 is locally thinned for the second time (see Figure 2 As shown in the figure, for the local area, the total amount of thinning reaches 6mm, and while thinning the cylindrical part, a step-shaped forming surface 5 is formed at the thinning feeding end of the second-pass local thinning barrel section (i.e., the transition part between the first-pass thinning barrel section and the second-pass local thinning barrel section), and the angle α1 between the forming surface and the axial direction of the barrel blank 1 is equal to 30 degrees, and then the flow wheel 3 is withdrawn in the radial direction;

[0039] S3, local shear forming:

[0040] Select Shear Wheel 4 (see Figure 6The angle between the upper shearing working surface 401 and the lower shearing working surface 402 of the shearing wheel is 90 degrees, and the lower shearing working surface is fitted to the outer surface of the thinned barrel section (the shearing amount is equal to 40% (and 4mm) of the single thinning amount of the second pass local thinning area in step S2, and the corresponding relative shearing amount is 40%), and the bottom of the forming surface in step S2 (the outer surface of the barrel that has been partially thinned) is used as the shearing starting position ( Figure 3 ), control the shearing wheel to perform axial shearing feed on the unthinned cylinder section, the shearing feed direction is consistent with the thinning feed direction, until the shearing feed distance reaches a preset value of 28mm, the shearing wheel is radially withdrawn, and an annular outer rib cylindrical part with a first high rib structure is prepared, and the cylindrical part is removed from the core mold.

[0041] Comparative Example 1

[0042] As a comparative experiment of Example 1, the cylindrical part with annular outer ribs formed in Example 1 is further processed to form a high-rib structure by using a traditional shearing process on the cylinder section (wall thickness of 10 mm) on the cylinder blank that has not been locally thinned. The specific operation is as follows:

[0043] Referring to step S1 of embodiment 1, the cylinder blank is installed, and the cylinder section on the cylinder blank that is not locally thinned is located on the outside;

[0044] The same shearing forming process as step S3 in Example 1 is selected, and the end of the non-locally thinned tube section of the tube blank is taken as the shearing starting position. The shearing wheel is controlled to perform axial shearing feed on the non-thinned tube section. The shearing depth is consistent with the shearing thickness of 4mm in Example 1 (the relative shearing amount is 40%), until the shearing feed distance reaches the preset value of 28mm, so as to form a second high rib structure on the annular outer rib cylindrical part of Example 1.

[0045] The outer shape structure of the annular outer rib cylindrical member having the first high rib structure and the second high rib structure is as follows: Figure 7 As shown, through the cross-section of the first high-rib structure and the second high-rib structure, it can be observed that the rib width of the first high-rib structure is relatively uniform, which is significantly improved compared to the second high-rib structure, and the cylinder body at the location of the second high-rib structure has a diameter expansion defect, and the warping deformation can be clearly seen through the cross-section. In the process of shearing the high-rib structure in Comparative Example 1, the forming of the cylinder section is basically achieved by the deformation of diameter expansion-neck contraction. Under such deformation conditions, the cylinder section is prone to diameter expansion defects.

[0046] In a specific embodiment, in order to make the annular outer rib cylindrical part have a plurality of first high rib structures, in step S2, the cylindrical blank is thinned in sections by a flow roller, and a plurality of locally thinned cylindrical sections are obtained in sequence along the thinning feeding direction, so that a forming surface is formed at the end of each locally thinned cylindrical section (see Figure 2As shown), then through step S3, an annular outer rib can be formed on each locally thinned barrel segment.

[0047] In another specific embodiment, the exit angle of the exit working surface of the flow wheel is β p , and β p Less than 30 degrees, after the first high rib structure is completed in step 3 of embodiment 1, the flow wheel is controlled to feed in the opposite direction of the thinning feed in step S2, so as to reshape the root of the annular outer rib formed in step S3 by exiting the working surface, and then remove the cylindrical part after reshaping. In this way, the width of the rib root can be further improved, and at the same time, the strain-hardened material can be prevented from cracking during the shear deformation process.

[0048] Comparative Example 2:

[0049] As a comparative experiment of Example 1, an original tube blank with a wall thickness of 10 mm was selected for direct local shearing and forming to compare the uniformity of the formed high-rib wall thickness. The specific operation steps are as follows:

[0050] Install the tube blank according to step S1 of Example 1;

[0051] The same shearing forming process as step S3 in Example 1 is selected, and the end of the tube blank is used as the shearing starting position. The shearing wheel is controlled to perform axial shearing feed. The shearing depth is consistent with the shearing thickness of 4mm in Example 1 (the relative shearing amount is 40%), until the shearing feed distance reaches the preset value of 28mm, so as to directly form a high-rib structure on the original tube blank that has not been thinned.

[0052] The slices of the workpiece with high rib structure formed in Example 1 and Comparative Example 2 are compared. Figure 8 As shown in the figure, it can be seen that the uniformity of thickness from the top of the rib to the root of the rib is significantly improved after the overall thinning by flow spinning, local thinning, and finally shearing. Therefore, the overall thinning of the present invention is to process harden the material as a whole, and the material after process hardening has obvious advantages in the uniformity of forming high rib structure.

[0053] 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 improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component, characterized in that: The following steps are involved: S1. Install the tube blank: Clamp the tube blank onto the mandrel of the spinning machine, and start the spinning machine to drive the tube blank to rotate synchronously with the mandrel; S2, Flow Spinning: A flow spinning wheel with a double-conical surface structure is selected for flow spinning. The flow spinning wheel includes a forming working surface and an exiting working surface connected by a circular arc working surface transition. The feed angle of the forming working surface is α p , 15 degrees <α p <45 degrees; the flow wheel is controlled to firstly perform one-pass overall thinning on the cylindrical blank, and then perform two-pass local thinning on the cylindrical blank, and a step-shaped forming surface is formed at the thinning feeding end of the two-pass local thinning section, and the angle α1 between the forming surface and the axial direction of the cylindrical blank is equal to α p ; S3, Shearing Forming: A shearing wheel is selected for local shearing and forming. The angle between the upper shearing working surface and the lower shearing working surface of the shearing wheel is 90 degrees. The lower shearing working surface is fitted to the outer surface of the second-pass locally thinned cylinder segment, and the bottom of the step of the forming surface in step S2 is used as the shearing starting position. The shearing wheel is controlled to perform axial shearing and feeding on the single-thinned cylinder segment. The shearing feed direction is consistent with the thinning feed direction until the shearing feed distance reaches a preset value to prepare a high-rib thin-walled cylindrical part.

2. The method for improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component according to claim 1, characterized in that: In step S2, the amount of thinning in the first pass of overall thinning is 20% to 30% of the thickness of the tube blank, and the total amount of thinning in the second pass of local thinning of the tube section is 40% to 60% of the thickness of the tube blank; in step S3, the shearing feed distance is 3 to 8 times the thinning amount.

3. The method for improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component according to claim 1, characterized in that: In step S2, the flow roller first performs one-pass overall thinning on the tube blank, and then performs two-pass local thinning in a segmented thinning manner, so that a forming surface is formed at the end of each locally thinned tube segment along the local thinning feed direction. Through step S3, annular external ribs can be formed at the thinning feed end of each locally thinned tube segment.

4. The method for improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component according to claim 1, characterized in that: The exit angle of the exit working surface of the flow wheel is β p , β p If the angle is less than 30 degrees, the flow roller is controlled to feed in the opposite direction of the thinning feed in step S2 so as to reshape the root of the annular outer rib formed in step S3 by exiting the working surface.

5. The method for improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component according to claim 4, characterized in that: 10 degrees < β p <30 degrees.

6. The method for improving the uniformity of rib thickness of a locally shear-formed high-rib thin-walled cylindrical component according to any one of claims 1 to 5, characterized in that: The rollers are symmetrically distributed on both sides of the cylindrical blank, and the various rollers are operated step by step during the forming process to act on the cylindrical blank at the same time.

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