Head forming mold and head forming method

Abstract

The present invention provides a head forming mold and a head forming method, which are implemented through the head forming mold. The head forming mold includes a male mold, a first edge pressing mold and a second edge pressing mold. The first edge pressing mold is arranged around the outer side of the circumference of the male mold, and the second edge pressing mold is arranged corresponding to the first edge pressing mold; the first edge pressing mold moves toward the second edge pressing mold to press the plate between the first edge pressing mold and the second edge pressing mold; during the pressing and forming process, the pressure of the first edge pressing mold on the plate is reduced. By reducing the pressure of the first edge pressing mold on the plate during the pressing and forming of the plate by the male mold, that is, reducing the clamping pressure of the first edge pressing mold and the second edge pressing mold on the plate, the plate material between the first edge pressing mold and the second edge pressing mold moves toward the male mold / mold cavity, thereby slowing down the speed of local stretching and thinning, so that the thickness of the formed head is more uniform. Therefore, on the basis of meeting the minimum thickness of each part of the head, the thickness of the plate material is reduced, and the cost of raw materials is reduced.

Description

Technical Field

[0001] The invention relates to a head forming technology, in particular to a head forming die and a head forming method. Background Art

[0002] Tank containers used to hold goods are widely used in the field of chemical product storage and transportation. The most common type of tank is composed of a cylindrical part in the middle and a head part at both ends. Depending on the size of the volume, the diameter of the cylinder and the head can be of various specifications. Among them, the head is generally made of a sheet through a pressing process. During the forming process, the sheet is pressed by the punch and deformed, and the sheet will be thinned to a certain extent relative to the original thickness after forming.

[0003] At present, in the existing head forming process, after the edge of the plate is clamped and fixed by the upper and lower clamping dies, during the process of the punch pressing the plate, the clamping force of the upper and lower clamping dies on the edge of the plate remains basically unchanged, while the magnitude of the tensile force and the tensile time applied to different parts of the plate are different, which is a factor leading to the relatively uneven thickness of the various parts of the head after forming.

[0004] To ensure that the minimum thickness of each part of the head must be greater than or equal to the minimum allowable thickness, thicker plates are required as forming raw materials, which makes the initial thickness of the raw materials required to be larger and the material cost higher. Summary of the invention

[0005] In order to solve the problems in the prior art of uneven thickness of end caps and high cost of raw materials, the present invention provides an end cap forming die and an end cap forming method.

[0006] A head forming method is implemented by a head forming mold.

[0007] The end-cap forming die comprises a male die, a first edge pressing die and a second edge pressing die, wherein the first edge pressing die is arranged around the outer side of the male die, and the second edge pressing die is arranged corresponding to the first edge pressing die;

[0008] A curved protrusion is provided on a side of the first edge pressing die facing the second edge pressing die, and a curved groove matching the curved protrusion is provided on a side of the second edge pressing die facing the first edge pressing die;

[0009] The plate is placed on the second edge-holding die, and the first edge-holding die moves toward the second edge-holding die to press the plate between the first edge-holding die and the second edge-holding die;

[0010] The convex die performs press forming on the plate, and during the press forming process, the pressure of the first edge clamping die on the plate is reduced.

[0011] Furthermore, the convex die performs press forming on the plate, and during the press forming process, the pressure of the first edge holding die on the plate is reduced, including:

[0012] The pressing movement stroke after the punch contacts the plate is divided into a plurality of stroke sections, and the pressure is reduced in sequence before each stroke section starts.

[0013] Furthermore, the diameter of the head is 2000-2500 mm, and the thickness of the plate is 5-8 mm;

[0014] The plurality of travel sections include a first travel section from 0 mm to 100-230 mm, a second travel section from 100-230 mm to 310-440 mm, a third travel section from 310-440 mm to 380-510 mm, and a fourth travel section from 380-510 mm to 470-600 mm;

[0015] Before the first stroke begins, the pressure is reduced to 25,500 to 26,500 kN;

[0016] Before the start of the second stroke, the pressure is reduced to 21500-22500 kN;

[0017] Before the third stroke section begins, the pressure is reduced to 19500-20500 kN;

[0018] Before the fourth stroke section begins, the pressure is reduced to 15500-16500 kN.

[0019] A head forming die, used in any of the head forming methods described above, comprising the male die, the first edge holding die and the second edge holding die;

[0020] The first edge clamping die is arranged around the outer side of the male die, and the second edge clamping die is arranged corresponding to the first edge clamping die. The male die is used for pressing the sheet material into shape, and the first edge clamping die is used for pressing the sheet material onto the second edge clamping die with adjustable pressure.

[0021] A curved protrusion is provided on a side of the first edge-pressing die facing the second edge-pressing die, and a curved groove matched with the curved protrusion is provided on a side of the second edge-pressing die facing the first edge-pressing die.

[0022] Furthermore, a first transition arc surface is provided at the bottom of the first edge-holding die near the male die, and the first transition arc surface is smoothly connected to a side surface of the second edge-holding die near the male die.

[0023] Furthermore, a second transition arc surface is provided at the bottom of the first edge-holding die, and the second transition arc surface is smoothly connected to the first transition arc surface.

[0024] Furthermore, a boss is provided at the bottom of the first edge-holding die near another side surface opposite to the one side surface, and the boss is pressed against the second edge-holding die to stop the first edge-holding die from continuing to move toward the second edge-holding die.

[0025] Furthermore, there is a gap between the side surface of the second edge holding die close to the punch and the punch.

[0026] Furthermore, the punch is a rotating body, the first edge-holding die is in a ring shape coaxial with the punch, and the second edge-holding die is in a ring shape corresponding to the first edge-holding die.

[0027] Furthermore, it also includes a concave die, which is fixedly arranged with the second edge-holding die and faces the convex die.

[0028] It can be seen from the above technical solution that the present invention has at least the following advantages and positive effects:

[0029] The head forming method of the present invention reduces the pressure of the first edge clamping die on the plate during the process of the punch pressing the plate, that is, reduces the clamping pressure of the first edge clamping die and the second edge clamping die on the plate, so that the plate material between the first edge clamping die and the second edge clamping die moves toward the punch and the die cavity, thereby alleviating the local excessive stretching and thinning, and making the thickness of the formed head more uniform. Therefore, on the basis of meeting the minimum thickness of each part of the head, the thickness requirement for the plate material can be reduced, and the cost of raw materials can be reduced. Moreover, since the thickness of each part of the head is relatively uniform, on the basis of meeting the minimum thickness of each part of the head, the weight of the head can also be reduced. The design of the curved surface protrusion on the first edge clamping die and the design of the curved surface groove on the second edge clamping die can make the plate part between the first edge clamping die and the second edge clamping die move toward the punch and the die cavity with a more appropriate friction force during the pressing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the steps of a head forming method in one embodiment of the present invention.

[0031] Figure 2 It is a schematic diagram of the partial cross-sectional structural state of the head forming mold in one embodiment of the present invention when the plate is placed on the second edge clamping mold and the punch and the first edge clamping mold are in contact with the plate.

[0032] Figure 3 and Figure 6 yes Figure 2 Schematic diagram of the partially enlarged structure.

[0033] Figure 4It is a schematic diagram of the local cross-sectional structure in which a sheet is placed on a lower edge-holding die and an upper edge-holding die contacts the sheet in a conventional solution.

[0034] Figure 5 yes Figure 2 Schematic diagram of the partially enlarged structure of the first edge-holding die.

[0035] The following are the descriptions of the reference numerals:

[0036] 1. Punch; 2. First pressing die; 21. Curved protrusion; 22. First transition arc surface; 23. Second transition arc surface; 24. Boss; 3. Second pressing die; 31. Curved groove; 4. Plate; 5. Gap. DETAILED DESCRIPTION

[0037] Although the present invention can be easily embodied in different forms of embodiments, only some of the specific embodiments are shown in the drawings and will be described in detail in this specification. It should be understood that this description should be regarded as an exemplary illustration of the principles of the present disclosure and is not intended to limit the present invention to that described herein.

[0038] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present disclosure, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0039] In the embodiments shown in the drawings, the indications of directions (such as up, down, left, right, front and back) used to explain the structure and movement of various elements of the present invention are not absolute but relative. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indications of these directions also change accordingly.

[0040] The preferred embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of this specification.

[0041] refer to Figure 1 and Figure 2 The head forming method of this embodiment is implemented by a head forming mold. The head forming mold includes a male mold 1, a first edge pressing mold 2 and a second edge pressing mold 3. The first edge pressing mold 2 is arranged around the outer side of the male mold 2, and the second edge pressing mold 3 is arranged corresponding to the first edge pressing mold 2.

[0042] The first edge-holding die 2 is provided with a curved protrusion 21 on one side facing the second edge-holding die 3, and the second edge-holding die 3 is provided with a curved groove 31 matching the curved protrusion 21 on one side facing the first edge-holding die 2. During the pressing process, the plate portion between the first edge-holding die 2 and the second edge-holding die 3 is moved toward the punch and the die cavity with a more appropriate friction force.

[0043] Generally, the second edge pressing die 3 is located below the first edge pressing die 2 and is fixedly arranged, so the second edge pressing die 3 is also called the edge pressing lower die. The first edge pressing die 2 is located above the second edge pressing die 3 and is also called the edge pressing upper die. The first edge pressing die 2 can be raised and lowered relative to the second edge pressing die 3 to press or unload the sheet 4.

[0044] The cross section of the tank body perpendicular to the axis is generally circular, so the end cap is a corresponding butterfly-shaped rotating body. When the end cap is a corresponding butterfly-shaped rotating body, the punch 1 for manufacturing the end cap is also a corresponding rotating body, and the plate 4 is a corresponding circular plate. The following describes the process steps of the end cap forming method of the present invention in the case where the punch 1 is a rotating body:

[0045] Step S1, placing the sheet on the second edge pressing die, the first edge pressing die moves toward the second edge pressing die, and the sheet is pressed between the first edge pressing die and the second edge pressing die;

[0046] Step S2, the convex die presses the plate into shape, and during the pressing process, the pressure of the first edge pressing die on the plate is reduced;

[0047] Step S3, releasing the pressure and demoulding, taking down the formed head, and producing the finished head through mechanical processing, shaping and trimming.

[0048] As described in step S1 above, the plate 4 is first placed on the second blanking die 3. When placing the plate 4 on the second blanking die 3, the portion of the plate 4 close to the circumferential edge should contact the second blanking die 3. Since the second blanking die 3 is an annular arrangement corresponding to the first blanking die 2, the plate 4 is supported on the second blanking die 3 by the portion close to the circumferential edge thereof, and the circumferential center of the plate 4 is opposite to the rotation center of the punch 1.

[0049] The first edge clamping die 2 moves downward under the drive of the edge clamping driving mechanism, and then clamps the plate 4 between the first edge clamping die 2 and the second edge clamping die 3 through its edge portion, preparing for the next step of the punch 1 to press and form the plate 4. The edge clamping driving mechanism is a thrust mechanism such as a hydraulic press.

[0050] As described in the above step S2, the punch 1 moves downward under the drive of the forming drive mechanism, contacts and presses the plate 4, so that the plate 4 is formed into a head shape similar to the punch 1 through the pressing and stretching of the plate 4 by the punch 1. Among them, the forming drive mechanism is a thrust mechanism such as a hydraulic press. In the process of pressing and forming, the edge clamping drive mechanism reduces the thrust on the first edge clamping die 2, thereby reducing the pressure of the first edge clamping die 2 on the plate 4, that is, reducing the clamping force of the first edge clamping die 2 and the second edge clamping die 3 on the plate 4, so that the edge of the plate 4 between the first edge clamping die 2 and the second edge clamping die 3 moves toward the punch 1 and the mold cavity.

[0051] As described in step S3 above, after the punch 1 completes the pressing and forming of the plate 4, it rises and resets under the drive of the forming drive mechanism. The first edge pressing die 2 rises under the drive of the edge pressing drive mechanism to release the pressure on the edge of the plate 4. Thus, the plate 4 that has been pressed is demoulded, and then the excess edge part of the plate 4 is trimmed, and the finished head is obtained through subsequent processes.

[0052] Along the moving direction of the punch 1, the angles between the sections corresponding to the curved surfaces of each part and the moving direction are different. The area of ​​the punch contacting the plate and the action time on each contact part are also increasing. That is, the magnitude of the tensile force and the tensile time of each part of the plate are different, which is a factor that leads to the uneven thickness of each part of the head after forming.

[0053] Through the above steps S1 and S2, during the process of the punch 1 pressing the sheet 4, the clamping force of the first and second edge clamping dies 2 and 3 on the edge of the sheet 4 is reduced, so that the sheet 4 material between the first and second edge clamping dies 2 and 3 moves toward the punch 1 and the die cavity, thereby slowing down the local stretching and thinning, and making the thickness of the formed head more uniform. Thus, on the basis of meeting the minimum thickness of each part of the head, the thickness of the sheet material is reduced, and the cost of raw materials is reduced. Moreover, since the thickness of each part of the head is relatively uniform, on the basis of meeting the minimum thickness of each part of the head, the weight of the head can also be reduced.

[0054] The step S2 in which the punch 1 presses the plate 4 and reduces the pressure of the first edge-holding die 2 on the plate 4 during the pressing process comprises:

[0055] Step S201, dividing the pressing movement stroke of the punch 1 after it contacts the plate 4 into a plurality of stroke sections, and reducing the pressure in sequence before the start of each stroke section according to the sequence of the stroke sections.

[0056] When the first clamping die 2 presses the edge portion of the plate 4 onto the second clamping die 3, the clamping drive mechanism applies a greater pressure to the first clamping die 2, so that the contact surface between the plate 4 and the curved protrusion 21 of the first clamping die 2 and the curved groove 31 of the second clamping die 3 is more closely fitted to ensure the clamping effect.

[0057] As described in step S201 above, after the punch 1 contacts the sheet 4, the pressing movement stroke of the sheet 4 is divided into multiple stroke sections. According to the sequence of the stroke sections, before the start of each stroke section, the pressure of the first pressing die 2 on the sheet 4 is reduced in sequence by the pressing drive mechanism. For example:

[0058] The pressing movement stroke after the punch 1 contacts the sheet 4 is divided into the first stroke section, the second stroke section, the third stroke section and the fourth stroke section in order. Before the punch 1 starts the first stroke section pressing the sheet 4, the pressure of the first edge pressing die 2 on the sheet 4 is first reduced, and then the punch 1 moves downward to complete the first stroke section of pressing. After completing the first stroke section, before starting the second stroke section, the pressure of the first edge pressing die 2 on the sheet 4 is further reduced, and then the second stroke section is completed. And so on, until the last stroke section is completed, the entire stroke of the punch pressing the sheet is completed.

[0059] Along the moving direction of the punch 1, the angles between the sections corresponding to the curved surfaces of each part and the moving direction are different. The section near the vertex of the punch 1 has a larger angle with the moving direction, while the section far from the vertex of the punch 1 has a smaller angle with the moving direction. As the pressing stroke of the punch 1 on the sheet 4 increases, the tension on the sheet 4 becomes greater and greater. By reducing the pressure of the first clamping die 2 on the sheet 4 in stages, the sheet material sandwiched between the first clamping die 2 and the second clamping die 3 can move toward the punch 1 and the mold cavity, thereby effectively slowing down the tendency of the sheet 4 to become rapidly thinned due to the increasing tension.

[0060] Embodiment 1:

[0061] The diameter of the end product is required to be 2000 mm, the initial pressure of the first blank holder 2 on the plate 4 is 28000 kN, and the four stroke sections of the punch 1 are divided as follows:

[0062] The first stroke section is from 0 mm to 100 mm after the punch 1 contacts the plate 4, the second stroke section is from 100 mm to 310 mm, the third stroke section is from 310 mm to 380 mm, and the fourth stroke section is from 380 mm to 470 mm.

[0063] Before each stroke section begins, the pressure of the first edge holding die 2 on the sheet 4 is reduced and adjusted as follows:

[0064] Before the first stroke begins, the pressure is reduced to 25,500 kN;

[0065] Before the start of the second stroke, the pressure is reduced to 21500 kN;

[0066] Before the third stroke section begins, the pressure is reduced to 19500 kN;

[0067] Before the fourth stroke section begins, the pressure is reduced to 15,500 kN.

[0068] According to the above parameter settings, the head product is obtained through the forming process.

[0069] According to actual measurement, the thickness of the plate material is 8 mm, which can make the thickness of each part of the formed head meet the minimum thickness requirement, while the ordinary head forming process requires the thickness of the plate material to be at least 8.3 mm so that the thickness of each part of the formed head can meet the minimum thickness requirement. That is, the thickness of the plate material can be reduced by at least 0.3 mm through the process parameter setting.

[0070] Embodiment 2:

[0071] The diameter of the head product is required to be 2500 mm, the initial pressure of the first blank holder on the plate is 28000 kN, and the four stroke sections of the punch 1 are divided as follows:

[0072] The first stroke section is from 0 mm to 230 mm after the punch 1 contacts the plate 4, the second stroke section is from 230 mm to 440 mm, the third stroke section is from 440 mm to 510 mm, and the fourth stroke section is from 510 mm to 600 mm.

[0073] Before each stroke section begins, the pressure of the first edge holding die 2 on the sheet 4 is reduced and adjusted as follows:

[0074] Before the first stroke begins, the pressure is reduced to 26500 kN;

[0075] Before the second stroke begins, the pressure is reduced to 22500 kN;

[0076] Before the third stroke section begins, reducing the pressure to 20500 kN;

[0077] Before the fourth stroke section begins, the pressure is reduced to 16500 kN.

[0078] According to the above parameter settings, the head product is obtained through the forming process.

[0079] According to actual measurement, the thickness of the plate material is 6 mm, which can make the thickness of each part of the formed head meet the minimum thickness requirement, while the ordinary head forming process requires the plate material thickness to be at least 6.25 mm so that the thickness of each part of the formed head can meet the minimum thickness requirement. That is, through the setting of this process parameter, the thickness of the plate material can be reduced by at least 0.25 mm.

[0080] Embodiment three:

[0081] The diameter of the head product is required to be 2380 mm, the initial pressure of the first blank holder on the plate is 28000 kN, and the four stroke sections of the punch are divided as follows:

[0082] The first stroke section is from 0 mm to 200 mm after the punch 1 contacts the plate 4, the second stroke section is from 200 mm to 410 mm, the third stroke section is from 410 mm to 480 mm, and the fourth stroke section is from 480 mm to 570 mm.

[0083] Before each stroke section begins, the pressure of the first edge holding die 2 on the sheet 4 is reduced and adjusted as follows:

[0084] Before the first stroke begins, the pressure is reduced to 26,000 kN;

[0085] Before the second stroke begins, the pressure is reduced to 22,000 kN;

[0086] Before the third stroke section begins, reducing the pressure to 20,000 kN;

[0087] Before the fourth stroke section begins, the pressure is reduced to 16,000 kN.

[0088] The stroke and pressure parameter settings are as follows:

[0089] Table 1 Stroke and pressure parameters

[0090]

[0091] According to the above parameter settings, the head product is obtained through the forming process.

[0092] According to actual measurement, the thickness of the plate material is 5.4 mm, which can make the thickness of each part of the formed head meet the minimum thickness requirement, while the ordinary head forming process requires the plate material thickness to be at least 5.6 mm to make the thickness of each part of the formed head meet the minimum thickness requirement. That is, the thickness of the plate material can be reduced by at least 0.20 mm through the process parameter setting.

[0093] In other embodiments, the pressure of the first edge clamping die on the sheet can be gradually and continuously reduced during the entire pressing movement after the punch contacts the sheet.

[0094] Continue to refer Figure 2 The present invention also provides a head forming die for realizing the above head forming method, comprising a male die 1, a female die, a first edge pressing die 2, a second edge pressing die 3, a forming drive mechanism and an edge pressing drive mechanism. The first edge pressing die 2 is arranged around the outer circumference of the male die, and the second edge pressing die 3 is arranged corresponding to the first edge pressing die 2.

[0095] The punch 1 is a rotating body, the first edge pressing die 2 is annular and coaxial with the punch 1, and the second edge pressing die 3 is annular and corresponds to the first edge pressing die 2. The concave die faces the punch 1 and is fixedly arranged on the lower die seat with the second edge pressing die 3.

[0096] The forming drive mechanism drives the punch 1 to complete the pressing and forming of the plate 4, and the edge pressing drive mechanism drives the first edge pressing die 2 to press the plate 4 between the first edge pressing die 2 and the second edge pressing die 3 with adjustable pressure. The edge pressing drive mechanism and the forming drive mechanism can be hydraulic cylinders.

[0097] Thus, in the process of the forming drive mechanism driving the punch 1 to press the plate 4 downward, the clamping force of the first clamping die 2 on the edge of the plate 4 can be reduced, so that the plate 4 raw material between the first clamping die 2 and the second clamping die 3 can move toward the punch 1 and the mold cavity, thereby slowing down the local stretching and thinning, making the thickness of the formed head more uniform, and reducing the thickness of the plate 4 raw material on the basis of meeting the minimum thickness of each part of the head, thereby reducing the raw material cost and the weight of the finished head.

[0098] refer to Figure 3 and Figure 4 The first margin die 2 is provided with a curved protrusion 21 on one side facing the second margin die 3. The curved protrusion 21 is cut with the plane where the axis of the punch 1 is located as the cross section, and the edge of the cut surface of the curved protrusion 21 is a smooth curve. The second margin die 3 is provided with a curved groove 31 that matches the curved protrusion 21 on one side facing the first margin die 2. The curved protrusion 21 and the curved groove 31 correspondingly arranged on the first margin die 2 and the second margin die 3 can not only reliably press the edge portion of the plate 4, but also, compared with the flat-bottom groove of the conventional margin die and the flat-bottom protrusion correspondingly arranged on the margin die, can reduce the resistance of the edge portion of the plate 4 clamped between the first margin die 2 and the second margin die 3 to move toward the punch 1 and the mold cavity during the process in which the punch 1 presses the plate 4 downward to deform the plate 4 downward into a head shape.

[0099] A boss 24 is provided at the bottom of the first edge clamping die 2 near the other side surface, and the boss 24 presses against the second edge clamping die 3 to stop the first edge clamping die 2 from moving further toward the second edge clamping die 3. Furthermore, there is a certain gap between the bottom of the first edge clamping die 2 and the second edge clamping die 3, except for the contact part of the boss 24, to prevent the pressure of the first edge clamping die 2 on the plate 4 from exceeding the set range.

[0100] refer to Figure 5 A first transition arc surface 22 is provided at the bottom of the first clamping die 2 near the punch 1, and the first transition arc surface 22 is smoothly connected to a side surface of the second clamping die 3 near the punch 1. The first transition arc surface 22 can be a circular arc chamfer at the intersection of the bottom surface of the first clamping die 2 and the side surface near the punch 1. A second transition arc surface 23 is provided at the bottom of the first clamping die 2, one end of the second transition arc surface 23 is smoothly connected to the first transition arc surface 22, and the other end of the second transition arc surface 23 is smoothly connected to the part of the bottom surface of the first clamping die near it.

[0101] When the first clamping die 2 presses the edge of the plate 4 downward, due to the extrusion effect of the curved protrusion 21 of the first clamping die 2 and the curved groove 31 of the second clamping die 3, the portion of the plate 4 close to the edge is bent into a shape suitable for the curved protrusion 21 and the curved groove 31, and then in the process of applying pressure, the rest of the plate 4 is warped upward. The setting of the first transition arc surface 22 and the second transition arc surface 23 can effectively reduce the friction of the bottom edge of the first clamping die 2 on the plate 4.

[0102] refer to Figure 6 There is a gap 5 between the side of the second edge clamping die 3 close to the punch 1 and the punch 1, which provides space for the plate 4 pressed between the first edge clamping die 2 and the second edge clamping die 3 to move toward the punch 1 and the die cavity. The size of the gap 5 is based on the standard of providing space for the plate 4 to move and having appropriate friction. Depending on the plate, the size of the gap 5 should be set between 5.5 mm and 9.5 mm to ensure that the plate has appropriate friction when moving.

[0103] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the present invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A head forming method, characterized in that: Implemented through the head forming mold, The end-cap forming die comprises a male die, a first edge pressing die and a second edge pressing die, wherein the first edge pressing die is arranged around the outer side of the male die, and the second edge pressing die is arranged corresponding to the first edge pressing die; A curved protrusion is provided on a side of the first edge pressing die facing the second edge pressing die, and a curved groove matching the curved protrusion is provided on a side of the second edge pressing die facing the first edge pressing die; The plate is placed on the second edge-holding die, and the first edge-holding die moves toward the second edge-holding die to press the plate between the first edge-holding die and the second edge-holding die; The punch presses the sheet and reduces the pressure of the first edge pressing die on the sheet during the pressing process, including: dividing the pressing movement stroke of the punch after it contacts the sheet into a plurality of stroke segments, and reducing the pressure before each stroke segment starts in sequence according to the sequence of the stroke segments; The diameter of the head is 2000-2500 mm, and the thickness of the plate is 5-8 mm; The plurality of travel segments include a first travel segment of ≥0 mm and <100 mm, a second travel segment of ≥100 mm and <310 mm, a third travel segment of ≥310 mm and <380 mm, and a fourth travel segment of ≥380 mm and ≤470 mm; or, A first travel section of ≥0 mm and <200 mm, a second travel section of ≥200 mm and <410 mm, a third travel section of ≥410 mm and <480 mm, and a fourth travel section of ≥480 mm and ≤570 mm; or, The first stroke section is ≥0 mm and <230 mm, the second stroke section is ≥230 mm and <440 mm, the third stroke section is ≥440 mm and <510 mm, and the fourth stroke section is ≥510 mm and ≤600 mm; Before the first stroke begins, reduce the pressure to 25,500-26,500 kN; Before the start of the second stroke, the pressure is reduced to 21500~22500 kN; Before the third stroke section begins, the pressure is reduced to 19500-20500 kN; Before the fourth stroke section begins, the pressure is reduced to 15500-16500 kN.

2. A head forming mold, characterized in that: The head forming mold can be used to form the head using the head forming method as claimed in claim 1; The first edge pressing die is used to press the plate onto the second edge pressing die with adjustable pressure; A first transition arc surface is provided at the bottom of the first edge pressing die near the male die, and the first transition arc surface is smoothly connected to a side surface of the first edge pressing die near the male die; A boss is provided at the bottom of the first edge pressing die near the other side surface opposite to the one side surface, and the boss is pressed against the second edge pressing die to stop the first edge pressing die from continuing to move toward the second edge pressing die.

3. The head forming mold according to claim 2, characterized in that: A second transition arc surface is provided at the bottom of the first edge pressing die, and the second transition arc surface is smoothly connected to the first transition arc surface.

4. The head forming mold according to claim 2, characterized in that: There is a gap between the side surface of the second edge holding die close to the punch and the punch.

5. The head forming mold according to claim 2, characterized in that: The punch is a rotating body, the first edge-holding die is in a ring shape coaxial with the punch, and the second edge-holding die is in a ring shape corresponding to the first edge-holding die.

6. The head forming mold according to claim 2, characterized in that: It also includes a concave die, which is fixedly arranged with the second edge-holding die and faces the convex die.

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