Internal high-pressure pre-expansion forming die

Abstract

The utility model discloses an internal high-pressure pre-expansion forming die. The internal high-pressure pre-expansion forming die comprises an upper die base, a lower die base, an upper movable die, a lower movable die, an upper middle limiting block and a lower middle limiting block, the upper die base is arranged above the lower die base, and the upper movable die, the lower movable die, the upper middle limiting block and the lower middle limiting block are arranged between the upper die base and the lower die base. The upper movable mold and the upper middle limiting block are correspondingly located above the lower movable mold and the lower middle limiting block respectively, a forming cavity is formed between the upper movable mold and the upper middle limiting block and between the lower movable mold and the lower middle limiting block, the two ends of the forming cavity are cylindrical, and the middle of the forming cavity is provided with a bulging part; the upper middle limiting block and the lower middle limiting block are located in the middle of the bulging part of the forming cavity. According to the pre-expansion forming mold, the straight pipe blank is subjected to pre-expansion treatment firstly, so that a semi-finished pipe with the middle part bulging and the wall thickness the same as that of a finished product is obtained, the number of times of subsequent pipe contracting and pipe expanding procedures can be reduced, the weight of the pipe is reduced, and the quality of the finished pipe product is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of metal workpiece processing, in particular to an internal high-pressure pre-expansion forming die. Background Art

[0002] Metal tubular hollow products are widely used in aerospace, automobile manufacturing, petrochemical and other industries. In the prior art, such products are generally prepared by pre-cutting to obtain an initial straight tube blank, and then the tube blank is subjected to an equal wall shrinking process through a tube shrinking machine in conjunction with a tube shrinking mold and other equipment. Finally, the shrunk tube is expanded according to the tubular structure required by the industry, and finally a finished tube with uniform wall thickness distribution in the entire forming area and a bulge in the middle is obtained. It can be seen that the processing procedures of the existing tubes with a bulge in the middle are mostly to first perform equal wall shrinking on the straight tube blank, and then use a mold to expand the tube at a preset position. However, in most cases, such tube shrinking and tube expansion processes cannot be achieved in one step, and may require two or even multiple steps of tube shrinking and tube expansion operations to finally form the final tube, which increases production costs and has low efficiency.

[0003] To this end, it is necessary to improve the processing procedure and design a pre-expansion forming mold. First, the straight tube blank is pre-expanded to obtain a semi-finished tube with a bulge in the middle and a wall thickness the same as the finished product. Then, the subsequent shrinking and expanding processes are carried out. This can reduce the number of subsequent shrinking and expanding processes, improve the quality of the finished tube, and reduce material costs. Utility Model Content

[0004] In order to overcome the deficiencies of the prior art, the utility model aims to provide an internal high-pressure pre-expansion forming die.

[0005] The purpose of the utility model is achieved by the following technical solution: an internal high-pressure pre-expansion forming mold, comprising an upper mold base, a lower mold base, an upper movable mold, a lower movable mold, an upper middle limit block, and a lower middle limit block; the upper mold base is arranged above the lower mold base, and the upper movable mold, the lower movable mold, the upper middle limit block, and the lower middle limit block are arranged between the upper mold base and the lower mold base;

[0006] The upper movable die and the upper middle limit block are respectively located above the lower movable die and the lower middle limit block. A forming cavity for placing the tube blank is provided between the upper movable die and the upper middle limit block and the lower movable die and the lower middle limit block. The forming cavity is a cavity with cylindrical ends and a bulging portion in the middle.

[0007] The upper middle limit block and the lower middle limit block are located in the middle of the bulging part of the molding cavity. There are two upper movable molds and two lower movable molds, which are respectively distributed on both sides of the upper middle limit block and the lower middle limit block.

[0008] Furthermore, the upper mold base is provided with a left-side limiting cavity, a middle limiting cavity, and a right-side limiting cavity for sequentially limiting the upper movable mold, the upper middle limiting block, and the upper movable mold, and the upper movable mold, the upper middle limiting block, and the upper movable mold are sequentially installed in the left-side limiting cavity, the middle limiting cavity, and the right-side limiting cavity; the lower mold base is provided with a left-side limiting cavity, a middle limiting cavity, and a right-side limiting cavity for sequentially limiting the lower movable mold, the lower middle limiting block, and the lower movable mold, and the lower movable mold, the lower middle limiting block, and the lower movable mold are sequentially installed in the left-side limiting cavity, the middle limiting cavity, and the right-side limiting cavity.

[0009] Furthermore, the internal high-pressure pre-expansion forming mold also includes a slide bar, and the upper mold base and the lower mold base are provided with installation steps for installing the slide bar, and the sides of the upper movable mold and the lower movable mold are recessed with slide grooves, and the upper movable mold and the lower movable mold are slidably mounted on the upper mold base and the lower mold base respectively through the slide bar.

[0010] Furthermore, a wear-resistant sheet is provided between the upper die base and the upper movable die; a wear-resistant sheet is provided between the lower die base and the lower movable die, and the wear-resistant sheet is composed of two layers, one layer of the wear-resistant sheet is fixed in the limiting groove of the upper die base or the lower die base, and the other layer of the wear-resistant sheet is fixed in the limiting groove of the upper movable die or the lower movable die.

[0011] Further, a limit groove is provided at the bottom of the upper movable mold, and a limit block which is adapted to the shape and size of the limit groove is provided at the top of the upper movable mold; or a limit block is provided at the bottom of the upper movable mold, and a limit groove which is adapted to the shape and size of the limit groove is provided at the top of the upper movable mold; or a limit block and a limit groove are provided at the bottom of the upper movable mold, and a limit groove and a limit block which are adapted to the shape and size of the limit block and the limit groove respectively are provided at the top of the upper movable mold.

[0012] Furthermore, the upper middle limit block and the contact position of the upper movable mold are respectively provided with an elastic member accommodating cavity, and an elastic member is arranged in the elastic member accommodating cavity; the lower middle limit block and the contact position of the lower movable mold are respectively provided with an elastic member accommodating cavity, and an elastic member is arranged in the elastic member accommodating cavity.

[0013] Furthermore, L-shaped limit blocks for limiting the ejection stroke of the upper movable mold and the lower movable mold are respectively provided on both sides of the upper mold base and the lower mold base; the L-shaped limit blocks on the same side are symmetrically arranged on the upper mold base and the lower mold base.

[0014] Furthermore, outer heads for covering the ends of the tube blanks are provided on both sides of the upper movable die and the lower movable die, and a sealing cavity is provided at the contact point between the outer head and the tube blank, and a sealing member is provided in the sealing cavity.

[0015] Furthermore, the outer head is provided with a water injection port for injecting high-pressure liquid into the tube blank.

[0016] Furthermore, equal-height columns are provided between the upper die base and the lower die base.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) The present application designs a pre-expansion forming die, which first pre-expands a straight tube blank to obtain a semi-finished tube with a bulge in the middle and a wall thickness that is the same as the wall thickness of the finished product, and then performs subsequent shrinking and expanding processes. This can reduce the number of subsequent shrinking and expanding processes and improve the quality of the finished tube.

[0019] In addition, in the pre-expansion forming mold, by designing an upper middle limit block and a lower middle limit block in the internal high-pressure pre-expansion forming mold, the forming pipe is clamped from the upper and lower positions, and the outer heads on the left and right sides simultaneously push the upper movable mold and the lower movable mold to move inward. The high-pressure liquid inside the pipe serves as support, so that the middle position of the pipe bulges. On the one hand, it can effectively limit the maximum expansion size so that the pre-forming wall thickness meets the forming wall thickness requirement, and the degree of standardization is high. On the other hand, it can effectively prevent the material from reducing the wall thickness during the high-pressure liquid push forming process, especially the middle position of the bulging part of the forming cavity, which is the position most prone to deformation.

[0020] (2) By designing a plurality of the above-mentioned limiting cavities, the present application can effectively fix a plurality of movable molds and middle limiting blocks on the upper mold base and the lower mold base, thereby meeting the mold limiting requirements for molding under high pressure conditions and improving the uniformity of the wall thickness of the molded pipe.

[0021] (3) The present application designs a slide bar, which, on the one hand, provides a certain guiding space for the installation of the movable mold and the mold base, and on the other hand, further improves the tight limiting effect between the upper mold base, the upper movable mold and the lower mold base, the lower movable mold, improves the sealing degree of the high-pressure molding conditions, effectively prevents horizontal displacement between the movable mold and the mold base, and further improves the wall thickness stability of the molded pipe.

[0022] (4) The present application designs two layers of wear-resistant sheets to effectively reduce the friction between the mold base and the movable mold, thereby increasing the service life of the upper and lower movable molds and improving the molding consistency of the internal high-pressure preforming.

[0023] (5) The present application designs a locking fit between the limit block and the limit groove, which, on the one hand, provides a certain alignment space for the installation of the upper movable mold and the lower movable mold, and on the other hand, further improves the tight limiting effect between the upper mold base, the upper movable mold and the lower mold base, the lower movable mold, improves the sealing degree of the high-pressure molding conditions, effectively prevents the movable mold and the mold base from shifting left and right, and further improves the wall thickness stability of the formed pipe.

[0024] (6) By setting an elastic component accommodating cavity between the middle limit block and the movable mold, when the tube blank completes the internal high-pressure pre-expansion forming, the movable molds on both sides are popped open by the elastic component, and the mold can be automatically popped open, which is convenient for taking out the product. The structure is simple and easy to disassemble.

[0025] (7) The present application designs an L-shaped limit block, which can effectively limit the ejection stroke of the movable mold and avoid safety accidents.

[0026] (8) The present application designs an external sealing head to wrap the two ends of the pipe inside, which can effectively prevent the leakage of high-pressure liquid and help the inner cavity of the pipe to establish internal high pressure to avoid deformation of the two ends. In addition, by providing a water injection port, high-pressure liquid is injected from the pipe blank to control the hydraulic pressure of the high-pressure liquid to meet the expansion requirements of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the cross-sectional structure of the high-pressure pre-bulking forming die in a preferred embodiment of the utility model;

[0028] Figure 2 It is a structural schematic diagram of another cross section of the high pressure pre-bulking forming die in a preferred embodiment of the utility model;

[0029] Figure 3 This is a structural schematic diagram of an upper die base or a lower die base of a preferred embodiment of the utility model;

[0030] Figure 4 This is a schematic diagram of the structure of the upper movable mold and the lower movable mold of a preferred embodiment of the utility model;

[0031] Figure 5 This is a schematic diagram of the structure of the upper middle limit block or the lower middle limit block of a preferred embodiment of the utility model;

[0032] Figure 6 This is a disassembly schematic diagram of a high-pressure pre-expansion forming mold in a preferred embodiment of the utility model;

[0033] Figure 7 This is a schematic diagram of the structure of the high pressure pre-bulking forming mold after assembly in a preferred embodiment of the utility model;

[0034] Figure 8 A schematic diagram of a formed pipe after being pre-expanded by a high pressure pre-expanding forming die in a preferred embodiment of the utility model;

[0035] In the figure: 1. Upper die base; 101. Left limit cavity; 102. Middle limit cavity; 103. Right limit cavity; 104. Mounting step; 105. Limiting groove; 2. Lower die base; 201. Left limit cavity; 202. Middle limit cavity; 203. Right limit cavity; 204. Mounting step; 205. Limiting groove; 3. Upper movable die; 301. Slide; 302. Limiting groove; 303. Limiting groove; 4. Lower movable die; 401, slide groove; 402, limit block; 403, limit groove; 5, upper middle limit block; 501, elastic member accommodating chamber; 6, lower middle limit block; 601, elastic member accommodating chamber; 7, forming chamber; 701, cylindrical; 702, bulging part; 8, slide bar; 9, wear-resistant sheet; 10, L-shaped limit block; 11, outer head; 1101, sealing chamber; 1102, water injection port; 12, equal height column; G0, tube blank; G1, formed pipe. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0037] like Figure 1-8 As shown, an internal high-pressure pre-expansion forming mold comprises an upper mold base 1, a lower mold base 2, an upper movable mold 3, a lower movable mold 4, an upper middle limit block 5, and a lower middle limit block 6; the upper mold base 1 is arranged above the lower mold base 2, and the upper movable mold 3, the lower movable mold 4, the upper middle limit block 5, and the lower middle limit block 6 are arranged between the upper mold base 1 and the lower mold base 2;

[0038] The upper movable mold 3 and the upper middle limit block 5 are respectively located above the lower movable mold 4 and the lower middle limit block 6. A forming cavity 7 for placing the tube blank G0 is provided between the upper movable mold 3, the upper middle limit block 5 and the lower movable mold 4, the lower middle limit block 6. The forming cavity 7 is a cavity with cylindrical ends 701 and a bulging portion 702 in the middle.

[0039] The upper middle limit block 5 and the lower middle limit block 6 are located in the middle of the bulging portion 702 of the molding cavity 7. There are two upper movable molds 3 and two lower movable molds 4, which are respectively distributed on both sides of the upper middle limit block 5 and the lower middle limit block 6.

[0040] The present application designs a pre-expansion forming die, which first pre-expands the straight tube blank G0 to obtain a semi-finished tube with a bulge in the middle and a wall thickness the same as the finished product wall thickness, and then performs subsequent shrinking and expanding processes. This can reduce the number of subsequent shrinking and expanding processes and improve the quality of the finished tube.

[0041] In addition, in the pre-expansion forming mold, by designing the upper middle limit block 5 and the lower middle limit block 6 in the internal high-pressure pre-expansion forming mold, the middle position of the bulging portion 702 of the forming tube is clamped from the upper and lower positions. On the one hand, it can effectively limit the maximum expansion amplitude, so that the molding quality is highly standardized. On the other hand, it can effectively prevent the material from wrinkling during the high-pressure liquid push molding process, especially the middle position of the bulging portion 702 of the molding cavity 7, which is the position most prone to deformation.

[0042] As a further preferred embodiment, the upper mold base 1 is provided with a left-side limiting cavity 101, a middle limiting cavity 102, and a right-side limiting cavity 103 for sequentially limiting the upper movable mold 3, the upper middle limiting block 5, and the upper movable mold 3. The upper movable mold 3, the upper middle limiting block 5, and the upper movable mold 3 are sequentially installed in the left-side limiting cavity 101, the middle limiting cavity 102, and the right-side limiting cavity 103; the lower mold base 2 is provided with a left-side limiting cavity 201, a middle limiting cavity 202, and a right-side limiting cavity 203 for sequentially limiting the lower movable mold 4, the lower middle limiting block 6, and the lower movable mold 4. The lower movable mold 4, the lower middle limiting block 6, and the lower movable mold 4 are sequentially installed in the left-side limiting cavity 201, the middle limiting cavity 202, and the right-side limiting cavity 203.

[0043] By designing a plurality of the above-mentioned limiting cavities, a plurality of movable molds and middle limiting blocks can be effectively fixed on the upper mold base 1 and the lower mold base 2, meeting the mold limiting requirements for molding under high pressure conditions and improving the wall thickness uniformity of the molded pipe G1.

[0044] As a further preferred embodiment, the internal high-pressure pre-expansion forming mold also includes a slide bar 8, and the upper mold base 1 and the lower mold base 2 are provided with installation steps 104 / 204 for installing the slide bar 8, and the sides of the upper movable mold 3 and the lower movable mold 4 are recessed with slide grooves 301 / 401, and the upper movable mold 3 and the lower movable mold 4 are slidably mounted on the upper mold base 1 and the lower mold base 2 respectively through the slide bar 8.

[0045] The present application designs a slide bar, on the one hand, to provide a certain guide space for the installation of the movable mold and the mold base, and on the other hand, to further improve the tight limiting effect between the upper mold base 1, the upper movable mold 3 and the lower mold base 2, the lower movable mold 4, improve the sealing degree of the high-pressure molding conditions, effectively prevent horizontal displacement between the movable mold and the mold base, and further improve the wall thickness stability of the formed tube G1.

[0046] As a further preferred embodiment, a wear-resistant sheet 9 is provided between the upper die base 1 and the upper movable die 3; a wear-resistant sheet 9 is provided between the lower die base 2 and the lower movable die 4, and the wear-resistant sheet 9 is two-layered, one layer of the wear-resistant sheet 9 is fixed in the limiting groove 105 / 205 of the upper die base 1 or the lower die base 2, and the other layer of the wear-resistant sheet 9 is fixed in the limiting groove 303 / 403 of the upper movable die 3 or the lower movable die 4.

[0047] The present application designs two layers of wear-resistant sheets 9 to effectively reduce the friction between the die base and the movable die, thereby improving the service life and molding quality of the internal high-pressure preforming.

[0048] As a further preferred scheme, a limit groove 302 is provided at the bottom of the upper movable mold 3, and a limit block 402 which is adapted to the shape and size of the limit groove is provided at the top of the upper movable mold 3; or a limit block is provided at the bottom of the upper movable mold 3, and a limit groove which is adapted to the shape and size of the limit groove is provided at the top of the upper movable mold 3; or a limit block and a limit groove are provided at the bottom of the upper movable mold 3, and a limit groove and a limit block which are adapted to the shape and size of the limit block and the limit groove respectively are provided at the top of the upper movable mold 3.

[0049] The present application designs the locking fit of the limit block and the limit groove, which, on the one hand, provides a certain alignment space for the installation of the upper movable mold 3 and the lower movable mold 4, and on the other hand, in order to further improve the tight limiting effect between the upper mold base 1, the upper movable mold 3 and the lower mold base 2, the lower movable mold 4, so that the pipe can be effectively prevented from being compressed, deformed and dislocated during pre-forming, and the left and right displacement between the movable mold and the mold base can be effectively prevented, thereby further improving the wall thickness stability of the formed pipe G1.

[0050] As a further preferred solution, the contact positions of the upper middle limit block 5 and the upper movable mold 3 are respectively provided with elastic member accommodating cavities 501, and elastic members are arranged in the elastic member accommodating cavities 501; the contact positions of the lower middle limit block 6 and the lower movable mold 4 are respectively provided with elastic member accommodating cavities 601, and elastic members (not shown in the figure) are arranged in the elastic member accommodating cavities 601. Preferably, the present application adopts a spring.

[0051] By setting an elastic component accommodating cavity between the middle limit block and the movable mold, when the tube blank G0 completes the internal high-pressure pre-expansion forming, the movable molds on both sides are popped open by the elastic component, and the movable molds at both ends of the mold can be automatically popped open, which is convenient for taking out the formed tube G1. The mold structure is simple and easy to disassemble.

[0052] As a further preferred solution, L-shaped limit blocks 10 for limiting the pop-up stroke of the upper movable mold 3 and the lower movable mold 4 are respectively provided on both sides of the upper mold base 1 and the lower mold base 2; the L-shaped limit blocks 10 on the same side are symmetrically arranged on the upper mold base 1 and the lower mold base 2.

[0053] The present application designs an L-shaped limit block 10, which can effectively limit the ejection stroke of the movable mold and avoid safety accidents.

[0054] As a further preferred embodiment, outer heads 11 for covering the ends of the tube blanks are provided on both sides of the upper movable mold 3 and the lower movable mold 4, and a sealing cavity 1101 is provided at the contact between the outer head 11 and the tube blank G0, and a high-pressure seal (not shown) is provided in the sealing cavity 1101.

[0055] As a further preferred solution, the outer head 11 is provided with a water injection port 1102 for injecting high-pressure liquid into the tube blank G0.

[0056] The present application designs an outer end cap 11 to wrap the two ends of the pipe inside, effectively preventing the pipe walls at both ends of the pipe from being compressed and deformed. In addition, a water injection port 1102 is provided to inject high-pressure liquid from the tube blank G0, and the hydraulic pressure of the high-pressure liquid is controlled to meet the expansion requirements of the material.

[0057] As a further preferred solution, equal-height columns 12 are further provided between the upper die base 1 and the lower die base 2 .

[0058] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. An internal high pressure pre-bulging forming die, characterized in that: It includes an upper die base, a lower die base, an upper movable die, a lower movable die, an upper middle limit block, and a lower middle limit block; the upper die base is arranged above the lower die base, and the upper movable die, the lower movable die, the upper middle limit block, and the lower middle limit block are arranged between the upper die base and the lower die base; The upper movable die and the upper middle limit block are respectively located above the lower movable die and the lower middle limit block. A forming cavity for placing the tube blank is provided between the upper movable die and the upper middle limit block and the lower movable die and the lower middle limit block. The forming cavity is a cavity with cylindrical ends and a bulging portion in the middle. The upper middle limit block and the lower middle limit block are located in the middle of the bulging part of the molding cavity. There are two upper movable molds and two lower movable molds, which are respectively distributed on both sides of the upper middle limit block and the lower middle limit block.

2. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: The upper mold base is provided with a left-side limiting cavity, a middle limiting cavity, and a right-side limiting cavity for sequentially limiting the upper movable mold, the upper middle limiting block, and the upper movable mold. The upper movable mold, the upper middle limiting block, and the upper movable mold are sequentially installed in the left-side limiting cavity, the middle limiting cavity, and the right-side limiting cavity; the lower mold base is provided with a left-side limiting cavity, a middle limiting cavity, and a right-side limiting cavity for sequentially limiting the lower movable mold, the lower middle limiting block, and the lower movable mold. The lower movable mold, the lower middle limiting block, and the lower movable mold are sequentially installed in the left-side limiting cavity, the middle limiting cavity, and the right-side limiting cavity.

3. The internal high pressure pre-bulking forming die according to claim 2, characterized in that: The internal high-pressure pre-expansion forming mold also includes a slide bar. The upper mold base and the lower mold base are provided with installation steps for installing the slide bar. The sides of the upper movable mold and the lower movable mold are recessed with slide grooves. The upper movable mold and the lower movable mold are slidably mounted on the upper mold base and the lower mold base respectively through the slide bar.

4. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: A wear-resistant sheet is provided between the upper die base and the upper movable die; a wear-resistant sheet is provided between the lower die base and the lower movable die, and the wear-resistant sheet is composed of two layers, one of which is fixed in the limiting groove of the upper die base or the lower die base, and the other is fixed in the limiting groove of the upper movable die or the lower movable die.

5. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: A limiting groove is provided at the bottom of the upper movable mold, and a limiting block which is adapted to the shape and size of the limiting groove is provided at the top of the upper movable mold; or a limiting block is provided at the bottom of the upper movable mold, and a limiting groove which is adapted to the shape and size of the limiting groove is provided at the top of the upper movable mold; or a limiting block and a limiting groove are provided at the bottom of the upper movable mold, and a limiting groove and a limiting block which are adapted to the shape and size of the limiting block and the limiting groove respectively are provided at the top of the upper movable mold.

6. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: The upper middle limit block and the upper movable mold contact position are respectively provided with an elastic component accommodating cavity, and an elastic component is arranged in the elastic component accommodating cavity; the lower middle limit block and the lower movable mold contact position are respectively provided with an elastic component accommodating cavity, and an elastic component is arranged in the elastic component accommodating cavity.

7. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: L-shaped limit blocks for limiting the ejection stroke of the upper movable mold and the lower movable mold are respectively arranged on both sides of the upper mold base and the lower mold base; the L-shaped limit blocks on the same side are symmetrically arranged on the upper mold base and the lower mold base.

8. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: External sealing heads for covering the ends of the tube blanks are arranged on both sides of the upper movable die and the lower movable die, and a sealing cavity is arranged at the contact point between the external sealing head and the tube blank, and a sealing member is arranged in the sealing cavity.

9. The internal high pressure pre-bulging forming die according to claim 8, characterized in that: The outer sealing head is provided with a water injection port for injecting high-pressure liquid into the tube blank.

10. The internal high pressure pre-bulging forming die according to claim 1, characterized in that: Equal height columns are also provided between the upper die base and the lower die base.

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