Single-point incremental composite hydroforming device

Abstract

The present invention discloses a single-point incremental composite hydraulic forming device for simultaneously forming thin-walled parts with complex shapes and concave-convex features in a single clamping operation. The device comprises a single-point incremental forming device and a hydraulic bulging device. The single-point incremental forming device comprises an oil chamber cylinder with an open top, an upper end cap disposed on the top end face of the oil chamber cylinder, a hollow middle portion of the upper end cap, an edge of a sheet to be formed positioned between the top end of the oil chamber cylinder and the upper end cap, a forming tool disposed above the sheet to be formed, and the oil chamber cylinder is connected to the hydraulic bulging device. The present invention can simultaneously form parts with complex shapes and concave-convex features in a single clamping operation, without requiring the use of molds, the addition of forming tools, the replacement of the size and shape of the forming tools, or the flipping of the sheet.

Description

Technical Field

[0001] The invention belongs to the technical field of metal sheet plastic forming equipment and relates to a single-point incremental composite hydraulic forming device. Background Art

[0002] Single-point incremental forming (SPIF) is a fast and flexible sheet metal forming process that uses only a single forming tool to form sheet metal into designed thin-walled parts by cumulative deformation point by point. Compared with traditional stamping and stretching processes, SPIF does not require dedicated molds and fixtures, offering advantages such as high flexibility, high efficiency, and low cost. It holds great promise for the small-batch, high-variety production of thin-walled parts such as covers, lids, shells, and plates in aerospace, new automobiles, and medical implants. However, without flipping the sheet, using molds, or adding additional forming tools, SPIF can only be used to form parts with concave features, such as frustums, truncated pyramids, and convex curved cones. Summary of the Invention

[0003] The purpose of the present invention is to provide a single-point incremental composite hydraulic forming device, which can simultaneously realize the forming of thin-walled parts with complex shapes and concave and convex features in one clamping.

[0004] The technical solution adopted by the present invention is a single-point incremental composite hydraulic forming device for processing the plate to be formed, including a single-point incremental forming device and a hydraulic bulging device. The single-point incremental forming device includes an oil cavity cylinder with an opening at the top, and the top end face of the oil cavity cylinder is provided with an upper end cover, the middle part of the upper end cover is empty, the edge of the plate to be formed is located between the top end of the oil cavity cylinder and the upper end cover, a forming tool is provided above the plate to be formed, and the oil cavity cylinder is connected to the hydraulic bulging device.

[0005] The present invention is also characterized in that:

[0006] A buffer pad is provided between the plate to be formed and the upper end cover.

[0007] A sealing groove is provided on the top end surface of the oil cavity cylinder, and a sealing ring is provided in the sealing groove.

[0008] The forming tool is a cylindrical bar stock, a movable ball is provided at the processing end of the forming tool, an oil hopper is provided on the side wall of the forming tool, and an oil path is provided in the forming tool, and the oil path leads from the oil hopper outlet to the movable ball.

[0009] Half of the movable ball body is a hemisphere and the other half is a semi-ellipsoid. The diameter of the hemisphere is equal to the diameter of the long axis of the hemisphere. A round rod shaft is arranged in the movable ball along the straight line where the long axis diameter of the hemisphere is located. Both ends of the round rod shaft are fixed to the processing end of the forming tool. The movable ball can rotate with the round rod shaft as the axis. The shape of the processing end of the forming tool matches the hemisphere of the movable ball. When the hemisphere of the movable ball is fully exposed, the hemisphere of the movable ball is completely embedded in the cylindrical bar stock, and the surface of the hemisphere fits the cylindrical bar stock.

[0010] A round zeolite is arranged in the oil funnel.

[0011] The oil cavity cylinder is provided with an oil inlet and an oil outlet. The oil inlet is arranged at a higher height than the oil outlet. The oil inlet and the oil outlet are respectively connected to the hydraulic bulging equipment through high-pressure hoses.

[0012] The hydraulic bulging equipment includes an oil tank, an upper cover plate is provided on the top of the oil tank, the oil tank is provided with a liquid level gauge, an air filter, and an oil suction filter, the oil suction filter is connected to a plunger pump, the plunger pump is connected to a three-phase asynchronous motor, the plunger pump is connected to one end of a one-way valve, the one-way valve is connected to a relief valve, a pressure gauge, an accumulator, and a reversing valve through a high-pressure hose, one end of the reversing valve is connected to the relief valve, the pressure gauge, and the accumulator, the other end of the reversing valve is connected to one end of a stop valve through a high-pressure hose, the other end of the stop valve is connected to the oil inlet of the single-point incremental forming equipment through the high-pressure hose, and the oil outlet of the single-point incremental forming equipment is connected to the inside of the oil tank through a high-pressure hose.

[0013] The beneficial effects of the present invention are:

[0014] The single-point incremental composite hydraulic forming device of the present invention combines single-point incremental forming and hydraulic bulging. During the single-point incremental forming process, by increasing the hydraulic bulging pressure to a certain extent, the forming of concave features and convex features can be simultaneously achieved in a one-time forming process. The present invention adds a buffer pad between the upper end cover and the plate to be formed, which can prevent the hydraulic oil between the upper end cover, the oil cavity and the plate from micro-leakage during excessive hydraulic bulging, thereby avoiding obvious wrinkles on the edge of the plate. The end of the forming tool that participates in the single-point incremental forming is equipped with a movable ball. The movable ball composed of a semi-ellipsoid and a semi-sphere can perform alternating rolling on the plate, converting part of the friction resistance into forming power and improving the lubrication effect. The side wall of the forming tool is provided with an oil hopper. The lubricating oil in the duckbill-shaped oil hopper containing round zeolite can be more accurately, evenly and stably applied to the surface of the plate to be formed through the movable ball, which is conducive to improving the surface quality of the formed part.

[0015] The accumulator in the hydraulic bulging equipment can store the pressure required for bulging in advance, which is conducive to the quantitative, instantaneous and stable supply of bulging pressure. This design not only realizes thin-walled parts with concave and convex features in one clamping and one forming, but also has good part forming quality, high cost-effectiveness and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the single-point incremental composite hydroforming device of the present invention;

[0017] Figure 2 is a cross-sectional view of a forming tool in a single-point incremental composite hydroforming device of the present invention;

[0018] Figure 3 Schematic diagram of the deformation process of the single-point incremental composite hydroforming device of the present invention;

[0019] Figure 4 This is a diagram of the actual forming process of the single-point incremental composite hydroforming device of the present invention when the buffer pad is not added and the oil funnel is added;

[0020] Figure 5 This is a diagram of the actual forming process of the single-point incremental composite hydraulic forming device of the present invention when a buffer pad is added but no oil hopper is added;

[0021] Figure 6 This is a real picture of the single-point incremental composite hydraulic forming device of the present invention when a buffer pad, an oil hopper and an accumulator are added.

[0022] In the figure, 1. oil chamber, 2. upper end cover, 3. buffer pad, 4. forming tool, 5. sheet to be formed, 6. sealing ring, 7. oil inlet, 8. oil outlet, 9. movable ball, 10. oil funnel, 11. oil tank, 12. liquid level gauge, 13. air filter, 14. oil suction filter, 15. plunger pump, 16. three-phase asynchronous motor, 17. one-way valve, 18. relief valve, 19. pressure gauge, 20. accumulator, 21. reversing valve, 22. stop valve, 23. upper cover, 24. high-pressure hose, 25. sheet to be formed. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] Example 1

[0025] This embodiment provides a single-point incremental composite hydraulic forming device for processing a circular plate 5 to be formed with a thickness of less than 5 mm. Figure 1 As shown, it includes a single-point incremental forming device and a hydraulic bulging device. The single-point incremental forming device includes a cylindrical oil cavity tube 1 with an opening at the top. The oil cavity tube 1 is filled with hydraulic oil. The top end face of the oil cavity tube 1 is provided with an upper end cover 2. The middle part of the upper end cover 2 is hollow. A side wall extends from the outer edge of the upper end cover 2. The inner side of the side wall of the upper end cover 2 is connected to the outer side of the side wall of the oil cavity tube 1 by a thread. The edge of the sheet material 5 to be formed is located between the top end of the oil cavity tube 1 and the upper end cover 2. An annular buffer pad 3 is provided between the sheet material 5 to be formed and the upper end cover 2. A sealing groove is provided on the top end face of the oil cavity tube 1. A sealing ring 6 is provided in the sealing groove. A forming tool 4 is provided above the sheet material 5 to be formed. The oil cavity tube 1 is connected to the hydraulic bulging device.

[0026] The single-point incremental composite hydraulic forming equipment can not only realize the single-point incremental forming of complex thin-walled plates with concave and convex features, but also prevent micro-leakage of hydraulic oil between the upper end cover 2 and the oil cavity cylinder 1 and the plate to be formed 5 during excessive hydraulic bulging, thereby avoiding wrinkles on the edge of the plate.

[0027] This embodiment only represents a preferred implementation of the single-point incremental composite hydraulic forming device of the present invention. Any forming device designed with similar technical features to the present invention will fall within the protection scope of the single-point incremental composite hydraulic forming device of the present invention.

[0028] Example 2

[0029] This embodiment provides a single-point incremental composite hydroforming device. Based on the embodiment 1, Figure 2 As shown, the forming tool 4 is a cylindrical rod, and the processing end of the forming tool 4 is equipped with a movable ball 9 through a round rod shaft. A duckbill oil funnel 10 is provided on the side wall of the forming tool 4, and a round zeolite is provided in the oil funnel 10. An oil circuit is provided in the forming tool 4, and the oil circuit leads from the outlet of the oil funnel 10 to the movable ball 9. After the lubricating oil in the duckbill oil funnel 10 is filtered and buffered by the internal round zeolite, it can be applied to the surface of the sheet to be formed more accurately, evenly and stably, which is conducive to improving the surface quality of the formed part.

[0030] The movable ball 9 has a half hemispherical body and a half ellipsoidal body. The diameter of the hemispherical body is equal to the long diameter of the hemispheroidal body. A round rod shaft is provided along the line of the long axis diameter of the hemispheroidal body in the movable ball 9. The two ends of the round rod shaft are fixed to the processing end of the forming tool 4. The movable ball 9 can rotate around the round rod shaft. The shape of the processing end of the cylindrical bar matches the hemispherical body of the movable ball 9. When the hemispherical body of the movable ball 9 is fully exposed, the hemispherical body of the movable ball 9 is completely embedded in the cylindrical bar, and the surface of the hemispherical body fits the cylindrical bar. The movable ball 9 can perform alternating rolling on the plate, thereby reducing the friction between the ball 9 and the plate 5 and increasing the forming power by changing the direction of the friction. At the same time, when the semicircular profile of the movable ball 9 completes contact with the plate 5, it enters the contact process of the semi-elliptical profile with the plate 5. During this process, there is a moment of separation between the movable ball 9 and the plate 5, and the lubricating oil will enter the separation gap, thereby improving the lubrication effect.

[0031] This embodiment only represents a preferred implementation of the single-point incremental composite hydraulic forming device of the present invention. Any forming device designed with similar technical features to the present invention will fall within the protection scope of the single-point incremental composite hydraulic forming device of the present invention.

[0032] Example 3

[0033] This embodiment provides a single-point incremental composite hydroforming device, based on the embodiment 1-2, as shown in FIG. Figure 1 As shown, the oil chamber cylinder 1 is provided with an oil inlet 7 and an oil outlet 8. The oil inlet 7 is arranged at a higher height than the oil outlet 8. The oil inlet 7 and the oil outlet 8 are respectively connected to the hydraulic bulging equipment through a high-pressure hose 24.

[0034] The hydraulic bulging equipment includes an oil tank 11, which is filled with hydraulic oil. The top of the oil tank 11 is provided with an upper cover 23 by screws. The oil tank 11 is provided with a liquid level gauge 12, an air filter 13, and an oil suction filter 14. The liquid level gauge 12, the air filter 13, and the oil suction filter 14 are placed inside the oil tank through the reserved holes on the oil tank upper cover 23, and the tops of the liquid level gauge 12, the air filter 13, and the oil suction filter 14 are respectively fixed to the upper cover 23 by screws. The oil suction filter 14 is connected to a plunger pump 15 provided inside the oil tank 11, and the plunger pump 15 is connected to a plunger pump located in the oil tank 11. The three-phase asynchronous motor 16 and the plunger pump 15 outside the box are connected to one end of the one-way valve 17. The one-way valve 17 is respectively connected to the overflow valve 18, the pressure gauge 19, the accumulator 20, and the reversing valve 21 through a high-pressure hose 24. One end of the reversing valve 21 is connected to the overflow valve 18, the pressure gauge 19, and the accumulator 20. The other end of the reversing valve 21 is connected to one end of the stop valve 22 through a high-pressure hose 24. The other end of the stop valve 22 is connected to the oil inlet 7 of the single-point incremental forming device through the high-pressure hose 24. The oil outlet 8 of the single-point incremental forming device is connected to the inside of the oil tank 11 through the high-pressure hose 24.

[0035] This embodiment only represents a preferred implementation of the single-point incremental composite hydraulic forming device of the present invention. Any forming device designed with similar technical features to the present invention will fall within the protection scope of the single-point incremental composite hydraulic forming device of the present invention.

[0036] like Figure 3 As shown, the hydraulic bulging equipment can provide a reverse bulging force to the sheet 25 being formed; while providing a smaller bulging pressure to the sheet being formed, the sheet is subjected to single-point incremental forming, and the sheet area not participating in the single-point incremental forming will gradually form convex features under the influence of the bulging pressure and the rebound of the sheet; storing the pressure in the accumulator 20 in advance is conducive to the instantaneous, quantitative and stable supply of the required pressure, avoiding the pressure fluctuations and extended bulging time caused by manual pressure adjustment (inconsistent bulging time will seriously affect the bulging height).

[0037] Compare Figure 4-5 and Figure 6 It can be found that when the single-point incremental composite hydraulic forming device of the present invention is used for forming without a cushion and an oil hopper, wrinkles will form on the edge of the sheet metal. However, with the oil hopper, the surface quality is acceptable. When the single-point incremental composite hydraulic forming device of the present invention is used for forming with a cushion but without an oil hopper, the surface quality of the sheet metal's concave features is low. However, when the single-point incremental composite hydraulic forming device of the present invention is used for forming with a cushion, an oil hopper, and an accumulator, the part forming quality is the highest. Therefore, the forming device of the present invention can simultaneously produce thin-walled parts with both concave and convex features in a single clamping and forming process without using a mold, increasing the number of forming tools, flipping the sheet metal, or changing the forming tools. Furthermore, the part forming quality is excellent, cost-effective, and easy to implement. This combination of equipment achieves the combined forming of single-point incremental forming and hydraulic bulging.

Claims

1. A single-point incremental composite hydraulic forming device for thin-walled parts with concave and convex features, used for processing a sheet material to be formed (5), characterized in that: It comprises a single-point incremental forming device and a hydraulic bulging device, wherein the single-point incremental forming device comprises an oil cavity cylinder (1) with an opening at the top, an upper end cover (2) is provided at the top end face of the oil cavity cylinder (1), the middle portion of the upper end cover (2) is hollow, the edge of the sheet material (5) to be formed is located between the top end of the oil cavity cylinder (1) and the upper end cover (2), a forming tool (4) is provided above the sheet material (5) to be formed, and the oil cavity cylinder (1) is connected to the hydraulic bulging device; A buffer pad (3) is provided between the plate to be formed (5) and the upper end cover (2); The forming tool (4) is a cylindrical bar stock, a movable ball (9) is provided at the processing end of the forming tool (4), an oil funnel (10) is provided on the side wall of the forming tool (4), and an oil path is provided in the forming tool (4), and the oil path is connected to the movable ball (9) from the outlet of the oil funnel (10); The movable ball (9) has a half-hemisphere and a half-ellipsoid, and is used for alternating rolling of the plate. The diameter of the hemisphere is equal to the diameter of the long axis of the hemisphere. A round rod shaft is provided in the movable ball (9) along the straight line where the long axis diameter of the hemisphere is located. Both ends of the round rod shaft are fixed to the processing end of the forming tool (4). The movable ball (9) can rotate around the round rod shaft. The shape of the processing end of the forming tool (4) matches the hemisphere of the movable ball (9). When the hemisphere of the movable ball (9) is fully exposed, the hemisphere of the movable ball (9) is completely embedded in the cylindrical bar material, and the surface of the hemisphere fits the cylindrical bar material. The oil chamber cylinder (1) is provided with an oil inlet (7) and an oil outlet (8), wherein the oil inlet (7) is arranged at a higher height than the oil outlet (8), and the oil inlet (7) and the oil outlet (8) are respectively connected to the hydraulic bulging equipment through a high-pressure hose (24); The hydraulic bulging equipment comprises an oil tank (11), a top cover plate (23) is provided on the top of the oil tank (11), the oil tank (11) is provided with a liquid level gauge (12), an air filter (13), and an oil suction filter (14), the oil suction filter (14) is connected to a plunger pump (15), the plunger pump (15) is connected to a three-phase asynchronous motor (16), the plunger pump (15) is connected to one end of a one-way valve (17), and the one-way valve (17) is respectively connected to an overflow valve (18), a pressure gauge (19), an accumulator (20), a reversing valve ( 21), one end of the reversing valve (21) is connected to the overflow valve (18), the pressure gauge (19), and the accumulator (20), the other end of the reversing valve (21) is connected to one end of the stop valve (22) through a high-pressure hose (24), the other end of the stop valve (22) is connected to the oil inlet (7) of the single-point incremental forming device through the high-pressure hose (24), and the oil outlet (8) of the single-point incremental forming device is connected to the inside of the oil tank (11) through the high-pressure hose (24); the single-point incremental composite hydraulic forming device can simultaneously realize the forming of complex-shaped parts with concave and convex features in one clamping.

2. The single-point incremental composite hydroforming device according to claim 1, characterized in that: The top end surface of the oil cavity cylinder (1) is provided with a sealing groove, and a sealing ring (6) is provided in the sealing groove.

3. The single-point incremental composite hydroforming device according to claim 1, characterized in that: Round zeolite is arranged in the oil funnel (10).

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