Hydraulic expansion mold with movable mold core

Abstract

The utility model discloses a hydraulic expansion mould with a movable mould core, which comprises an upper module and a lower module, the upper module comprises an upper mould, the lower module comprises a lower mould, the upper mould forms an upper mould cavity, the lower mould forms a lower mould cavity, and the upper mould and the lower mould form a lower mould cavity. The upper mold cavity and the lower mold cavity are opposite to each other and are combined to form a final forming cavity for accommodating a preformed pipe blank, so that a final forming pipe blank is formed through stamping; a pitched roof insert capable of floating up and down is arranged at the position, located in the middle of the lower mold cavity, in the lower mold, and the end face of the abutting end of the pitched roof insert is matched with the lower surface of the bulging part of the finally-formed pipe blank in a concave-convex mode. According to the utility model, the two ends are fixed without floating, and the middle part is movably stamped through the inclined top insert and is expanded through high-pressure liquid, so that a pipe blank is completely attached to the die, the cracking problem caused by non-uniform wall thickness is effectively avoided, and the rejection rate is reduced.

Description

Technical Field

[0001] This utility model relates to the field of metal workpiece processing technology, specifically to a core-moving hydraulic expansion mold. Background Technology

[0002] Tubular hollow products are used in many fields. These products are generally manufactured using hydroforming. Hydroforming involves placing a tubular blank of a certain length into a mold, and under the pressure of an internal liquid (liquid or oil), the blank expands radially outward by controlling the internal pressure, resulting in plastic deformation to form a hollow structural component. However, some materials, due to their inherent physical properties—for example, bridge housings are made of carbon steel—have a low expansion coefficient due to the material's inherent properties. Furthermore, bridge housings are large-section, irregularly shaped, and complex structures, especially the lower rear cover area which has multiple right-angle, small-radius corner structures—making forming difficult and causing problems such as cracking and inability to form. In general expansion forming processes, the material stagnates during forming due to the right-angle corner structures, preventing further expansion and stretching, which could lead to cracking. Utility Model Content

[0003] To address the technical problems existing in the prior art, the purpose of this utility model is to provide a hydraulic expansion mold with a movable mold core, which produces bridge housing products with uniform wall thickness and is not prone to cracking.

[0004] The objective of this utility model is achieved through the following technical solution: a core-moving hydraulic expansion mold, comprising an upper mold assembly and a lower mold assembly, wherein the upper mold assembly includes an upper mold, and the lower mold assembly includes a lower mold, wherein the upper mold forms an upper mold cavity, and the lower mold forms a lower mold cavity, wherein the upper mold cavity and the lower mold cavity are opposite to each other and combined to form a final forming cavity for accommodating a preformed tube blank, for stamping to form a final formed tube blank; wherein a vertically floating inclined top insert is provided in the lower mold at the middle position of the lower mold cavity, and the end face of the abutment of the inclined top insert matches the concave and convex lower surface of the bulge of the final formed tube blank.

[0005] Furthermore, a lower middle module is provided in the lower mold at the middle position of the lower mold cavity. The upper surface of the lower middle module forms a bulging cavity. The lower middle module is provided with an inclined through groove that penetrates the surface of the bulging cavity formed by the lower middle module. The through groove is movably connected to the inclined top insert. One end of the inclined top insert is connected to the telescopic rod of the driving device, and the other end of the inclined top insert extends into the through groove. This extended end is the abutment end of the inclined top insert. Under the drive of the driving device, the abutment end of the inclined top insert can extend further from the through groove into the bulging cavity formed by the lower middle module.

[0006] Specifically, there are two inclined top inserts, and correspondingly, there are also two through slots, and the center lines of the two through slots intersect in the bulging cavity formed by the lower middle module.

[0007] Furthermore, the lower module also includes a lower mold base, and the lower mold also includes a lower left module and a lower right module. The lower left module and the lower right module are located on both sides of the lower middle module, and the lower left module, the lower middle module and the lower right module are integrally formed with the lower mold base.

[0008] Furthermore, the upper module also includes an upper mold base, through which the upper mold is mounted; the upper mold includes an upper left module, a middle upper module group, and an upper right module, with the upper left module and the upper right module located on both sides of the middle upper module group.

[0009] Specifically, the upper mold base is provided with a left cavity, a middle cavity and a right cavity, which are respectively installed with the upper left module, the upper middle module group and the upper right module.

[0010] Furthermore, the left cavity is provided with a first spring group, and the two ends of each spring in the first spring group abut against the upper left module and the upper mold base respectively; the right cavity is provided with a second spring group, and the two ends of each spring in the second spring group abut against the upper right module and the upper mold base respectively.

[0011] Specifically, the upper middle module group includes an upper middle module, four upper punches, and two stops. The four upper punches surround the upper middle module. Two of the upper punches connect to the upper left module on both sides of the semi-tubular cavity formed by the upper left module in the radial direction. These two upper punches are the upper left punches. The other two upper punches connect to the upper right module on both sides of the semi-tubular cavity formed by the left and right modules in the radial direction. These two upper punches are the upper right punches. Each stop is located between the upper left punch and the upper right punch on the same side, so that the upper middle module, the four upper punches, and the two stops form a bulging cavity.

[0012] Furthermore, the surfaces of the four upper punches used to form the cavity are partially concave to form inclined surfaces. These inclined surfaces are located at the points where they connect with the upper left or upper right module, and are used to punch out the connection points between the shrinking and bulging parts of the final formed tube blank.

[0013] Specifically, it also includes two sealing plugs, which are respectively set on both sides of the upper module and the lower module.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] 1. Compared with existing technologies, the left and right ends of the existing final forming mold are floating, while the middle part is fixed and cannot float. The products produced in this process still have uneven wall thickness, which easily leads to cracking in actual applications. In contrast, this utility model uses a fixed end that does not float, while the middle part uses a sliding top insert for moving stamping and high-pressure liquid expansion to ensure that the tube blank is completely attached to the mold. This effectively avoids cracking due to uneven wall thickness and reduces the scrap rate.

[0016] 2. The lower left module, lower middle module and lower right module in the lower mold of this utility model can be integrally formed with the lower mold base, simplifying the structure.

[0017] 3. This utility model uses the first spring group and the second spring group to elastically abut against the upper left and upper right modules of the upper mold, so that the fastening force that holds the two ends of the tube blank in place is gentle and has a buffer space.

[0018] 4. The upper and middle module assembly of this utility model consists of an upper and middle module, four upper punches, and two stops, which together form a bulging cavity, effectively restricting the expansion of the tube blank. Furthermore, the inclined surface of the upper punches effectively punches out the connection between the shrinking and bulging parts of the final formed tube blank, helping the manufactured product to meet the required shape.

[0019] 5. The final tube blank produced by this utility model has good concentricity and coaxiality. Attached Figure Description

[0020] Figure 1 This is a half-sectional view of the present invention.

[0021] Figure 2 This is an exploded view of the lower middle module and the inclined top insert of this utility model.

[0022] Figure 3 This is an anatomical diagram of the upper and lower modules of this utility model.

[0023] Figure 4 This is a schematic diagram of the structure of the present invention for removing the upper mold base.

[0024] Figure 5 This is an anatomical diagram of the upper mold base and the middle and upper module assembly of this utility model.

[0025] Figure 6 This is a schematic diagram of the upper punch and stop block of this utility model.

[0026] Figure 7 This is a schematic diagram of the preformed tube blank.

[0027] Figure 8 This is a schematic diagram of the final formed tube blank, with the upper surface of the tube blank facing upwards.

[0028] Figure 9 This is a schematic diagram of the final formed tube blank, with the lower surface of the tube blank facing upwards.

[0029] For ease of understanding, all the above figures are longitudinal sectional views.

[0030] In the picture:

[0031] 10-Upper module; 12-Upper mold base; 121-Left cavity; 122-Middle cavity; 123-Right cavity; 140-Upper mold cavity; 141-Upper left module; 1425-Upper middle module; 1426-Upper punch; 14260-Sloping surface; 1427-Stop block; 143-Upper right module; 17-First spring group; 18-Second spring group;

[0032] 20 - Lower module; 23 - Lower mold base; 250 - Lower mold cavity; 251 - Lower left module; 2522 - Lower middle module; 25220 - Through slot; 2524 - Angled top insert; 25240 - Top abutment; 2526 - Drive device; 253 - Lower right module;

[0033] 30 - Sealing plug;

[0034] G0 - Preformed tube blank; G - Final formed tube blank; 601 - Bulging part; 603 - Shrinking part; 605 - Connecting part. Detailed Implementation

[0035] To facilitate understanding of this utility model, the technical solutions and advantages of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Any mechanisms or methods not elaborated in this utility model can be referred to in the prior art. The specific structures and features of this utility model are illustrated below by way of example and should not constitute any limitation on this utility model. Furthermore, any technical feature mentioned below (including implicit or disclosed features), as well as any technical feature directly shown or implied in the figures, can be arbitrarily combined or deleted among these technical features to form more other embodiments that may not be directly or indirectly mentioned in this utility model. The accompanying drawings show preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0036] This utility model discloses a core-moving hydraulic expansion mold, comprising an upper mold assembly and a lower mold assembly. The upper mold assembly includes an upper mold base and an upper mold, while the lower mold assembly includes a lower mold base and a lower mold. The upper mold is mounted via the upper mold base, and the lower mold is mounted via the lower mold base. The upper mold forms an upper mold cavity, and the lower mold forms a lower mold cavity. The upper mold cavity and the lower mold cavity are opposite to each other and combined to form a final forming cavity for accommodating a preformed tube blank, thereby forming the final formed tube blank by stamping. A vertically floating inclined top insert is provided in the lower mold at the center of the lower mold cavity. The end face of the top of the inclined top insert matches the concave and convex shape of the lower surface of the bulge portion of the final formed tube blank.

[0037] like Figure 1-9 As shown, the hydraulic expansion mold with movable mold core in this embodiment includes an upper mold assembly 10, a lower mold assembly 20, and a sealing plug 30. The upper mold assembly 10 is disposed above the lower mold assembly 20, and there are two sealing plugs 30, which are respectively disposed on both sides of the upper mold assembly 10 and the lower mold assembly 20.

[0038] Specifically, the upper module 10 includes an upper mold base 12 and an upper mold. The upper mold is installed through the upper mold base 12 and forms a downward-facing upper mold cavity 140.

[0039] The upper mold includes an upper left module 141, an upper middle module group, and an upper right module 143. The upper left module 141 and the upper right module 143 are located on both sides of the upper middle module group, and their shapes and structures are mirror images of each other. Correspondingly, the upper mold base 12 has a left cavity 121, a middle cavity 122, and a right cavity 123, which are respectively installed on the upper left module 141, the upper middle module group, and the upper right module 143. The left cavity 121 is provided with a first spring group 17. The two ends of each spring in the first spring group 17 abut against the upper left module 141 and the upper mold base 12, respectively. The first spring group 17 is used to elastically press the upper left module 141 downwards, and the lower surface of the upper left module 141 forms a semi-tubular cavity. The right cavity 123 is provided with a second spring group 18. The two ends of each spring in the second spring group 18 abut against the upper right module 143 and the upper mold base 12 respectively. The second spring group 18 is used to elastically press the upper right module 143 downward. The lower surface of the upper right module 143 forms a semi-tubular cavity.

[0040] The upper middle module group includes an upper middle module 1425, four upper punches 1426, and two stops 1427. The four upper punches 1426 surround the upper middle module 1425. Two of the upper punches 1426 connect to the upper left module 141 on both radial sides of the semi-tubular cavity formed by the upper left module 141, and these two upper punches 1426 are the upper left punches 1426. The remaining two upper punches 1426 connect to the upper right module 143 on both radial sides of the semi-tubular cavity formed by the left and right modules, and these two upper punches 1426 are the upper right punches 1426. Each stop 1427 is positioned between the upper left punch 1426 and the upper right punch 1426 on the same side, so that the upper middle module 1425, the four upper punches 1426, and the two stops 1427 form a bulging cavity. When the preformed tube blank G0 is placed inside and high-pressure liquid is injected, the bulging cavity formed by the upper and middle module group restricts the expansion of the tube blank, making it conform to the outer contour requirements of the upper surface of the final formed tube blank G. Specifically, the surfaces of the four upper punches 1426 that form the cavity are partially concave to form inclined surfaces 14260. The inclined surfaces 14260 are located at the connection points with the upper left module 141 or the upper right module 143, and are used to punch out the connection 605 between the constricted portion 603 and the bulging portion 601 of the final formed tube blank G. The semi-tubular cavities formed by the upper left module 141 and the upper right module 143 and the bulging cavity formed by the upper and middle module group are connected to form the upper mold cavity 140.

[0041] The lower module 20 includes a lower mold base 23 and a lower mold. The lower mold is installed through the lower mold base 23 and forms an upward-facing lower mold cavity 250.

[0042] The lower mold includes a lower left module 251, a lower middle module group, and a lower right module 253. The lower left module 251 and the lower right module 253 are located on either side of the lower middle module group, and their shapes and structures are mirror images of each other. The upper surfaces of the lower left module 251 and the lower right module 253 each form a semi-tubular cavity. The lower left module 251 corresponds to the upper left module 141, and the lower right module 253 corresponds to the upper right module 143.

[0043] The lower and middle module assembly includes a lower and middle module 2522, two inclined top inserts 2524, and a driving device 2526. The upper surface of the lower and middle module 2522 forms a bulging cavity that matches and connects with the bulging cavity formed by the upper and middle module assemblies. The lower and middle module 2522 has two inclined through slots 25220 that penetrate the surface of the bulging cavity formed by the lower and middle module 2522, and the centerlines of the two through slots 25220 intersect within the bulging cavity formed by the lower and middle module 2522. The through slots 25220 are movably connected to the inclined top inserts 2524. One end of the inclined top insert 2524 is connected to the telescopic rod of the driving device 2526; this end is the connecting end of the inclined top insert 2524. The other end of the inclined top insert 2524 extends into the through slot 25220; this extended end is the abutment 25240 of the inclined top insert 2524. Driven by the drive device 2526, the abutment 25240 of the inclined top insert 2524 can extend further into the bulging cavity formed by the middle and lower module 2522 through the through groove 25220. The end face of the abutment 25240 matches the concave and convex lower surface of the bulging part of the final formed tube blank G to stamp out the outer contour of the lower surface of the bulging part of the final formed tube blank G.

[0044] The lower left module 251, the lower middle module 2522, and the lower right module 253 can be integrally formed with the lower mold base 23, simplifying the structure. The semi-tubular cavities formed by the lower left module 251 and the lower right module 253 are connected with the bulging cavity formed by the lower middle module group to form the lower mold cavity 250. The upper mold cavity 140 is opposite to the lower mold cavity 250, and the two are combined to form the final forming cavity for accommodating the preformed tube blank G0, so as to stamp the final formed tube blank G.

[0045] There are two sealing plugs 30, namely a left sealing plug 30 and a right sealing plug 30, which are respectively set on both sides of the upper module 10 and the lower module 20. The sealing plugs 30 are used to seal the G0 pipe opening of the preformed tube blank. The internal high-pressure equipment connects to the inside of the tube blank through the sealing plug 30 via the filling pipeline.

[0046] Instructions for using this invention to prepare the final tube blank G:

[0047] First, the preformed tube blank G0 is placed between the upper and lower molds, and the preformed tube blank G0 is held in place by the upper mold cavity 140 and the lower upper mold cavity 140. The sealing plug 30 seals both ends of the preformed tube blank G0. At this time, the inclined top insert 2524 is in the state of being withdrawn from the bulging cavity.

[0048] Then, the upper mold moves downward under the action of the hydraulic cylinder, and the lower mold forces the first spring group 17 and the second spring group 18 to compress. The upper mold and the lower mold fit together without any irregularities. The sealing plug 30 enters the interior of the preformed tube blank G0 to the appropriate position, and the filling pipeline begins to fill the interior of the preformed tube blank G0 with high pressure, so that the bulge of the preformed tube blank G0 expands to fit the mold cavity.

[0049] Subsequently, the drive unit lifts the inclined ejector block 2524, pressing the pre-formed tube blank G0. Specifically, a high-pressure water pressure of 60-80 MPa is applied first, the inclined ejector block 2524 lifts the tube blank, and a high pressure of 140 MPa is maintained for 3-5 seconds, allowing sufficient space for retraction and forming to prevent cracking. Under the combined action of the high-pressure liquid and the inclined ejector block 2524, the tube blank expands until it is completely attached to the mold, completing the forming process.

[0050] Finally, remove the mold and take out the final shaped tube blank G.

[0051] Compared to existing technologies, the left and right ends of the current final forming mold are floating, while the middle part is fixed and cannot float. This process still results in uneven wall thickness in the product, which easily leads to cracking in practical applications. In contrast, the hydraulic expansion mold with a movable mold core in this embodiment uses a fixed, non-floating end design, with the middle part utilizing a sliding top insert for pressing and high-pressure liquid expansion, ensuring the tube blank completely adheres to the mold. This effectively avoids cracking caused by uneven wall thickness and reduces the scrap rate. The final formed tube blank produced by this embodiment exhibits good concentricity and coaxiality.

[0052] The above embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of protection of the present utility model. For those skilled in the art, it will be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A hydraulic expansion mold with a movable mold core, characterized in that, The device includes an upper module and a lower module. The upper module includes an upper mold, and the lower module includes a lower mold. The upper mold forms an upper mold cavity, and the lower mold forms a lower mold cavity. The upper mold cavity and the lower mold cavity are opposite to each other and combined to form a final forming cavity for accommodating a preformed tube blank, so as to stamp and form a final formed tube blank. In the lower mold, a sloping top insert that can float up and down is provided at the middle of the lower mold cavity. The end face of the top of the sloping top insert matches the concave and convex shape of the lower surface of the bulge of the final formed tube blank.

2. The core-moving hydraulic bulging mold as described in claim 1, characterized in that, A lower middle module is also provided in the lower mold at the middle part of the lower mold cavity. The upper surface of the lower middle module forms a bulging cavity. The lower middle module is provided with an inclined through groove that penetrates the surface of the bulging cavity formed by the lower middle module. The through groove is movably connected to the inclined top insert. One end of the inclined top insert is connected to the telescopic rod of the driving device, and the other end of the inclined top insert extends into the through groove. The other end of the inclined top insert is the abutment of the inclined top insert. Under the drive of the driving device, the abutment of the inclined top insert can extend further from the through groove into the bulging cavity formed by the lower middle module.

3. The core-moving hydraulic bulging mold as described in claim 2, characterized in that, There are two inclined top inserts, and correspondingly, there are also two through slots, and the center lines of the two through slots intersect in the bulging cavity formed by the lower middle module.

4. The core-moving hydraulic bulging mold as described in claim 2, characterized in that, The lower module also includes a lower mold base, and the lower mold also includes a lower left module and a lower right module. The lower left module and the lower right module are located on both sides of the lower middle module, and the lower left module, the lower middle module and the lower right module are integrally formed with the lower mold base.

5. The hydraulic expansion mold with movable mold core as described in claim 1, characterized in that, The upper module also includes an upper mold base, through which the upper mold is mounted; the upper mold includes an upper left module, a middle upper module group and an upper right module, with the upper left module and the upper right module located on both sides of the middle upper module group.

6. The core-moving hydraulic bulging mold as described in claim 5, characterized in that, The upper mold base is provided with a left cavity, a middle cavity and a right cavity, which are respectively installed with the upper left module, the upper middle module group and the upper right module.

7. The core-moving hydraulic bulging mold as described in claim 6, characterized in that, The left cavity is provided with a first spring group, and the two ends of each spring in the first spring group abut against the upper left module and the upper mold base respectively; the right cavity is provided with a second spring group, and the two ends of each spring in the second spring group abut against the upper right module and the upper mold base respectively.

8. The core-moving hydraulic bulging mold as described in claim 5, characterized in that, The upper and middle module group includes an upper and middle module, four upper punches, and two stops. The four upper punches surround the upper and middle module. Two of the upper punches connect to the upper left module on both sides of the semi-tubular cavity formed by the upper left module in the radial direction. These two upper punches are the upper left punches. The other two upper punches connect to the upper right module on both sides of the semi-tubular cavity formed by the left and right modules in the radial direction. These two upper punches are the upper right punches. Each stop is located between the upper left punch and the upper right punch on the same side, so that the upper and middle module, the four upper punches, and the two stops form a bulging cavity.

9. The core-moving hydraulic bulging mold as described in claim 8, characterized in that, The surfaces of the four upper punches that form the cavity are partially concave to form inclined surfaces. These inclined surfaces are located at the junctions with the upper left or upper right module and are used to punch out the junctions between the shrinking and bulging portions of the final formed tube blank.

10. The core-moving hydraulic bulging mold as described in claim 1, characterized in that, It also includes two sealing plugs, which are respectively located on both sides of the upper and lower modules.

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