Bending forming die and bending method

Abstract

The invention discloses a bending forming die which comprises a female die, a central male die, a side male die and a compression spring. The two side male dies are symmetrically distributed on the two sides of the center male die, and the center male die can move relative to the side male dies. The female die is provided with a groove and two inclined forming surfaces, and the intersection point of extension lines of the two inclined forming surfaces is located in the groove. The central convex die is provided with a bending head which is arranged corresponding to the groove; the cross section of the bending head is V-shaped, and the bending head is provided with an upper surface; a compression spring is arranged between the side male die and the center male die, and the side male die abuts against the upper surface of the bending head under the action of the compression spring. And the bending head and the two side male dies form a V-shaped male die together. According to the invention, a bent part with good dimensional precision can be obtained only through any single-action press and one-time bending forming action; the die is simple in structure and has the advantages of being convenient to operate, high in forming precision, large in machining flexibility and the like.

Description

Technical Field

[0001] The invention relates to a bending forming die and a bending method, belonging to the technical field of plate bending forming. Background Art

[0002] In actual engineering applications, when conventional bending methods are used to bend sheet metal, the springback is often large, requiring multiple bendings, which affects the dimensional accuracy of the product. When the stretch bending process is used for bending, the requirements for the shape of the parts are relatively strict, and the processing efficiency is low. When the press bending method is used to reduce springback, on the one hand, the required forming force is large, which reduces the durability of the mold, and on the other hand, it will cause indentations on the surface of the sheet metal, affecting the appearance quality. The bending method that compensates for springback has the disadvantage of poor processing flexibility, that is, a set of molds can only maintain high-precision forming for a certain material and a specific specification. Summary of the invention

[0003] In order to overcome the problems existing in the prior art, the present invention provides a bending forming die and a bending method, which are beneficial to reducing the springback after bending. The specific technical solution is as follows.

[0004] A bending forming die, characterized in that it comprises a concave die, a central convex die, a side convex die and a compression spring;

[0005] The two side punches are symmetrically distributed on both sides of the central punch, and the central punch can move relative to the side punches;

[0006] The concave mold has a groove and two inclined molding surfaces, and the intersection of the extended lines of the two inclined molding surfaces is located in the groove;

[0007] The central male mold has a bending head, the bending head is arranged corresponding to the groove, and the cross-sectional width of the bending head is smaller than the cross-sectional width of the groove; the cross-sectional shape of the bending head is V-shaped, and the bending head has an upper surface;

[0008] The compression spring is arranged between the side punch and the center punch, and the side punch abuts against the upper surface of the bending head under the action of the compression spring; the bending head and the two side punches together form a V-shaped punch.

[0009] By adopting the above technical solution, the bending head and the two side punches together form a V-shaped punch, which can bend the plate in cooperation with the die. At the same time, after the plate is bent, the center punch can continue to press down relative to the side punches for further bending, thereby reducing the amount of springback of the bent plate.

[0010] Furthermore, the central punch comprises a vertical support component, a horizontal support component and the bending head, the two side punches are located on both sides of the vertical support component, the bending head is fixed to the lower end of the vertical support component, and the bending head is also located below the side punch; the horizontal support component is fixedly connected to the vertical support component, and the horizontal support component is located above the side punch, and the compression spring is located between the horizontal support component and the side punch. The horizontal support component is provided to better set the compression spring to ensure that the side punch can move between the bending head and the horizontal support component; the vertical support component can be used as a sliding guide component of the side punch to limit the relative movement position relationship between the side punch and the vertical support component.

[0011] Furthermore, the horizontal support component is provided with a through hole, the side punch is provided with a screw hole corresponding to the through hole, a bolt passes through the through hole and is screwed into the screw hole, and the compression spring is sleeved on the bolt. The compression spring applies a downward elastic force to the side punch so that the side punch abuts against the upper surface of the bending head. The bolt is used to position the compression spring and to change the spacing between the horizontal support component and the side punch to accommodate further downward pressure of the center punch. At the same time, by replacing different compression springs, the elastic force of the compression spring can be adjusted, that is, the pressure of the side punch pressing the sheet can be adjusted to accommodate the bending requirements of different materials.

[0012] Based on the same inventive concept, the present invention also relates to a bending method, which adopts the above-mentioned bending forming mold and mainly includes the following steps:

[0013] 1) placing a sheet on the die, and moving the central punch and the side punch together downward to bend the sheet, and the bent sheet is clamped between the die and the side punch;

[0014] 2) While keeping the side punch in close contact with the sheet, the center punch moves further downward to press the sheet, and at this time, the side punch is separated from the upper surface of the bending head;

[0015] 3) The center punch and the side punch move upward to take out the plate.

[0016] Furthermore, in the above step 2), the distance that the center punch moves downward is 0.08-0.5 times the thickness of the plate; preferably, the distance that the center punch moves downward is 0.1 times the thickness of the plate.

[0017] The present invention can obtain bent parts with good dimensional accuracy by any single-action press only with one bending and forming action; the mold structure of the present invention is simple, and has the characteristics of convenient operation, high forming accuracy, and great processing flexibility, that is, only one set of molds is needed to form bent parts of various materials and different specifications with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the bending forming die of the present invention (first stage of bending);

[0019] Figure 2 is a schematic diagram of the bending forming die of the present invention (second stage of bending);

[0020] Figure 3 It is a schematic diagram of the concave die;

[0021] Figure 4 is a schematic diagram of the center punch;

[0022] Figure 5 is a schematic diagram of the side punch;

[0023] Figure 6 yes Figure 1 A magnified image of area A;

[0024] Figure 7 This is a simulation diagram of the bending of a traditional one-piece bending punch, where (a) shows the angle before springback, (b) shows the angle after springback, and (c) shows the change in sheet thickness;

[0025] Figure 8 It is a simulation diagram of the split bending punch bending of the present invention, wherein (a) shows the angle before springback, (b) shows the angle after springback, and (c) shows the change in plate thickness.

[0026] In the figure: die 1, groove 1.1, inclined forming surface 1.2, center punch 2, bending head 2.1, upper surface 2.1.1, vertical support part 2.2, horizontal support part 2.3, through hole 2.3.1, side punch 3, screw hole 3.1, compression spring 4, bolt 5, plate 6. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0028] See also Figure 1-Figure 6 , a bending forming die, which includes a concave die 1, a central punch 2, a side punch 3 and a compression spring 4;

[0029] The two side punches 3 are symmetrically distributed on both sides of the center punch 2, and the center punch 2 can move relative to the side punches 3;

[0030] The die 1 has a groove 1.1 and two inclined molding surfaces 1.2, and the intersection point of the extended lines of the two molding surfaces 1.2 is located in the groove 1.1;

[0031] The central punch 2 has a bending head 2.1, which is arranged corresponding to the groove 1.1, and the cross-sectional width of the bending head 2.1 is smaller than the cross-sectional width of the groove 1.1; the cross-sectional width of the bending head 2.1 is V-shaped, and the bending head 2.1 has an upper surface 2.1.1; wherein the cross-sectional width of the bending head 2.1 is smaller than the cross-sectional width of the groove 1.1 to ensure that the bending head 2.1 can extend into the groove 1.1 to achieve secondary stretching of the bent sheet;

[0032] A compression spring 4 is provided between the side punch 3 and the center punch 2. The side punch 3 abuts against the upper surface 2.1.1 of the bending head 2.1 under the action of the compression spring 4; the bending head 2.1 and the two side punches 3 together form a V-shaped punch.

[0033] Among them, the central punch 2 includes a vertical support component 2.2, a horizontal support component 2.3 and a bending head 2.1, two side punches 3 are located on both sides of the vertical support component 2.2, the bending head 2.1 is fixed to the lower end of the vertical support component 2.2, and the bending head 2.1 is also located below the side punch 3; the horizontal support component 2.3 is fixedly connected to the vertical support component 2.2, and the horizontal support component 2.3 is located above the side punch 3, and the compression spring 4 is located between the horizontal support component 2.3 and the side punch 3. The horizontal support component 2.3 is provided in order to better arrange the compression spring 4 to ensure that the side punch 3 can move between the bending head 2.1 and the horizontal support component 2.3; the vertical support component 2.2 can be used as a sliding guide component of the side punch 3 to limit the relative movement position relationship between the side punch 3 and the vertical support component 2.2. The vertical support member 2.2 and the horizontal support member 2.3 can be integrally formed or split; the vertical support member 2.2 and the horizontal support member 2.3 can be detachably connected by fasteners. In a preferred embodiment, the bending head 2.1 is detachably connected to the vertical support member 2.2, so that when a bending head 2.1 with a different bending angle is needed, the corresponding bending head 2.1 can be easily replaced.

[0034] Preferably, the horizontal support component 2.3 is provided with a through hole 2.3.1, the side punch 3 is provided with a screw hole 3.1 corresponding to the through hole 2.3.1, the bolt 5 passes through the through hole 2.3.1 and is screwed into the screw hole 3.1, and the compression spring 4 is sleeved on the bolt 5. The compression spring 4 applies a downward elastic force to the side punch 3, so that the side punch 3 abuts against the upper surface 2.1.1 of the bending head 2.1. The bolt 5 is used to position the compression spring 4 and to change the spacing between the horizontal support component 2.3 and the side punch 3 to accommodate further downward pressure of the center punch 2. At the same time, by replacing different compression springs 4, the elastic force of the compression spring 4 can be adjusted, that is, the pressure of the side punch 3 pressing the plate 6 can be adjusted to accommodate the bending requirements of different materials.

[0035] The present invention also relates to a bending method, which adopts the above-mentioned bending forming mold and mainly comprises the following steps:

[0036] 1) Place the sheet 6 on the die 1, move the center punch 2 and the side punch 3 downward together, bend the sheet 6, and the bent sheet 6 is clamped between the die 1 and the side punch 3 (the first stage of bending);

[0037] 2) While keeping the side punch 3 close to the plate 6, the center punch 2 moves further downward to press the plate 6. At this time, the side punch 3 is separated from the upper surface 2.1.1 of the bending head 2.1 (the first stage of bending);

[0038] 3) The center punch 2 and the side punch 3 move upward to take out the plate 6.

[0039] Furthermore, in the above step 2), the distance that the center punch 2 moves downward is 0.08-0.5 times the thickness of the plate 6; preferably, the distance that the center punch 2 moves downward is 0.1 times the thickness of the plate 6. The center punch 2 can continue to be pressed downward relative to the side punch 3 to further bend, thereby reducing the springback amount of the bent plate 6.

[0040] Figure 7-Figure 8 The simulation of bending a 2mm thick plate using a conventional one-piece bending punch and a split bending punch (separate center punch and side punch) of the present application is shown. The springback angle of the conventional one-piece bending punch after bending is 1.2 degrees, while the springback angle of the split bending punch of the present application after bending is 0.3 degrees, wherein the distance that the center punch 2 moves further into the lower groove 1.1 is 0.1 times the thickness of the plate 6. At the same time, the thinnest thickness of the plate after bending by the two bending methods differs by only 0.01mm, which shows that the bending method of the present application has little effect on the change of plate thickness.

[0041] The embodiments of the present invention are described above in conjunction with the accompanying drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention is not limited to the above-mentioned specific implementations, which are merely illustrative and not restrictive. Under the enlightenment of the present invention, those skilled in the art can also make many forms without departing from the scope of protection of the present invention and the claims, all of which belong to the protection scope of the present invention.

Claims

1. A bending forming die, characterized in that: It comprises a concave die (1), a central convex die (2), a side convex die (3) and a compression spring (4); The two side punches (3) are symmetrically distributed on both sides of the central punch (2), and the central punch (2) is movable relative to the side punches (3); The concave mold (1) has a groove (1.1) and two inclined molding surfaces (1.2), and the intersection point of the extended lines of the two inclined molding surfaces (1.2) is located in the groove (1.1); The central punch (2) has a bending head (2.1), the bending head (2.1) is arranged corresponding to the groove (1.1), and the cross-sectional width of the bending head (2.1) is smaller than the cross-sectional width of the groove (1.1); the cross-sectional shape of the bending head (2.1) is V-shaped, and the bending head (2.1) has an upper surface (2.1.1); The compression spring (4) is arranged between the side punch (3) and the center punch (2); the side punch (3) abuts against the upper surface (2.1.1) of the bending head (2.1) under the action of the compression spring (4); the bending head (2.1) and the two side punches (3) together form a V-shaped punch.

2. A bending forming mold according to claim 1, characterized in that: The central punch (2) comprises a vertical supporting component (2.2), a horizontal supporting component (2.3) and a bending head (2.1); the two side punches (3) are located on both sides of the vertical supporting component (2.2); the bending head (2.1) is fixed to the lower end of the vertical supporting component (2.2); and the bending head (2.1) is also located below the side punch (3); the horizontal supporting component (2.3) is fixedly connected to the vertical supporting component (2.2), and the horizontal supporting component (2.3) is located above the side punch (3); and the compression spring (4) is located between the horizontal supporting component (2.3) and the side punch (3).

3. A bending forming mold according to claim 2, characterized in that: The horizontal supporting component (2.3) is provided with a through hole (2.3.1), the side punch (3) is provided with a screw hole (3.1) corresponding to the through hole (2.3.1), the bolt (5) passes through the through hole (2.3.1) and is screwed into the screw hole (3.1), and the compression spring (4) is sleeved on the bolt (5).

4. A bending method, which uses the bending forming mold according to any one of claims 1 to 3, mainly comprising the following steps: 1) placing a plate (6) on the die (1), moving the central punch (2) and the side punch (3) downward together to bend the plate (6), and the bent plate (6) is clamped between the die (1) and the side punch (3); 2) While keeping the side punch (3) in close contact with the plate (6), the center punch (2) moves further downward to press the plate (6), at which time the side punch (3) is separated from the upper surface (2.1.1) of the bending head (2.1); 3) The central punch (2) and the side punch (3) move upward to take out the plate (6).

5. A bending forming die according to claim 4, characterized in that: In the above step 2), the distance that the central punch (2) moves downward is 0.08-0.5 times the thickness of the plate (6).

6. A bending forming mold according to claim 5, characterized in that: The distance that the central punch (2) moves downward is 0.1 times the thickness of the plate (6).

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