Hot-press forming die and hot forming process for light-weight parts of vehicle body

Abstract

The invention discloses a hot-press forming die and a hot forming process for light-weight parts of a vehicle body, and belongs to the technical field of dies. Comprising an upper die assembly and a lower die assembly which are connected in a sliding mode, a male die is installed on the upper die assembly, a female die is installed on the lower die assembly, an adjusting plate is connected to the male die in a sliding mode, and a plurality of sliding blocks are connected to the male die in a sliding mode; the pushing and ejecting assembly comprises a supporting pipe connected with the lower die assembly in a sliding mode, an ejecting plate is fixedly installed on the supporting pipe, a punch matched with the female die in an inserted mode is fixedly installed on the ejecting plate, an ejecting column is connected into the supporting pipe in a sliding mode, and a lifting frame connected with the supporting pipe in a sliding mode is fixedly installed on the ejecting column. By means of the process design that hot press forming is conducted firstly and then ring cutting is delayed, burr deformation caused by high-temperature edge cutting is avoided, low-temperature brittle cracking is prevented, the part edge cutting precision and quality are improved, meanwhile, the secondary laser cutting procedure needed by a traditional process is omitted, and the process complexity and the production cost are reduced.

Description

Technical Field

[0001] The present invention relates to the field of mold technology, and more specifically, to a hot pressing mold for lightweight vehicle body parts and a hot forming process thereof. Background Art

[0002] Hot pressing technology has significant advantages in the field of automobile body manufacturing. Its process characteristics are mainly reflected in the following aspects: First, this technology can produce ultra-high-strength body structural parts; second, it can effectively reduce the weight of the body; third, it can improve the safety and comfort of the body; fourth, it significantly improves the dimensional accuracy of parts; fifth, it enhances surface hardness, dent resistance and corrosion resistance.

[0003] After thermoforming, existing lightweight components still require laser cutting equipment for contour finishing to ensure dimensional stability. This not only increases the complexity of the production process but also raises overall manufacturing costs. To address this, we propose a thermoforming die and thermoforming process for lightweight vehicle body components. Summary of the Invention

[0004] The purpose of the present invention is to provide a hot pressing forming mold and a hot pressing process for lightweight car body parts, which are used to solve the technical problem in the prior art that hot pressing forming and ring cutting of forming materials require two production processes, increasing the process complexity and production cost.

[0005] An embodiment of the present invention provides a hot pressing forming die for lightweight vehicle body parts, comprising an upper die assembly and a lower die assembly slidably connected to each other, wherein a punch is mounted on the upper die assembly, and a die is mounted on the lower die assembly. An adjustment plate is slidably connected to the punch, and a plurality of sliders are slidably connected to the punch, and the sliders push the adjustment plate to align with the punch forming surface.

[0006] The ejector assembly includes a support tube slidably connected to the lower die assembly, a top plate fixedly mounted on the support tube, a punch fixedly mounted on the top plate that plugs and cooperates with the die, a top column slidably connected in the support tube, and a lifting frame slidably connected to the support tube fixedly mounted on the top column;

[0007] The top column drives the lifting frame to rise ahead of the support tube under the driving action, so that the lifting frame lifting control slider releases the adjustment plate limit. The rising of the support tube can enable the punch to cut the edge of the molding material in the set temperature range.

[0008] As a further description of the above technical solution, a shift rod is fixedly mounted on the slider, and a guide groove and a reversing groove that are interconnected are provided on the lifting frame, and the shift rod slides in the guide groove and the reversing groove.

[0009] As a further description of the above technical solution, a third elastic member is mounted on the top column and is used to push the lifting frame and abut the top of the support tube.

[0010] As a further description of the above technical solution, it also includes a plurality of ejector rods slidably connected to the lower mold assembly, the ejector rods are inserted into the die, the end faces of the ejector rods are aligned with the cavity surface of the die, and positioning blocks are fixedly installed on the ejector rods;

[0011] A push plate is fixedly installed at the bottom of the lifting frame, and the push plate is used to control the push rod to slide in the die.

[0012] As a further description of the above technical solution, the lower die assembly includes a lower die base, a ramp block is slidably connected to the lower die base, and a first elastic member for pushing the ramp block toward the support tube is installed in the lower die base;

[0013] A fourth elastic member for rebounding the ejector rod is installed on the lower die base.

[0014] As a further description of the above technical solution, a plurality of pull rods slidably connected to the adjustment plate are fixedly mounted on the punch, and a second elastic member for pushing the adjustment plate to align with the punch forming surface is mounted on the punch.

[0015] As a further description of the above technical solution, the top of the punch is aligned with the top of the die, and the inner side of the punch is aligned with the inner edge of the adjustment plate.

[0016] As a further description of the above technical solution, the lifting frame is slidably connected to the upper mold assembly and the lower mold assembly.

[0017] As a further description of the above technical solution, a circulating water channel for cooling the molding material is provided on the male mold.

[0018] The present invention also provides a thermoforming process for lightweight vehicle body parts, comprising the following steps:

[0019] S1, heating the blank to 900-950°C and transferring it to the cavity of the hot pressing mold;

[0020] S2, the hot press drives the punch down and cooperates with the die to hot press the blank;

[0021] S3. When the molding material is cooled to 110-190℃, the hot press drives the ejector assembly to rise and cut the edge of the molding material;

[0022] S4. After the circular cutting is completed, the hot press drives the ejector assembly to descend and controls the ejector rod to rise to eject the molding material out of the concave mold cavity.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] 1. The present invention adopts a process design of first hot pressing and then delayed ring cutting, which not only avoids burr deformation caused by high-temperature cutting, but also prevents low-temperature brittle cracking, improves the precision and quality of component cutting, and eliminates the secondary laser cutting process required by traditional processes, reducing process complexity and production costs.

[0025] 2. The present invention cooperates with the pre-compression amount of the third elastic part through the top column and the support tube, so that the slider can first release the limit of the adjustment plate and then drive the punch to cut the forming material in a circular manner, so that the adjustment plate has a restraining force on the blank during the forming stage, reducing problems such as edge warping of parts. At the same time, after the circular cutting, the adjustment plate can effectively push the cutting material to the punch, reducing the difficulty of subsequent transfer.

[0026] 3. When the push column of the present invention drives the push plate to descend, it can push the inclined block to move, and then the inclined block controls the push rod to rise, so as to eject the molding material in the concave mold cavity and reduce the difficulty of unloading. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the overall structure of a hot pressing mold for a lightweight vehicle body component disclosed in a preferred embodiment of the present invention;

[0028] Figure 2 A cross-sectional view of a hot pressing mold for a lightweight vehicle body component disclosed in a preferred embodiment of the present invention;

[0029] Figure 3 A schematic diagram of a portion of the structure of a hot pressing mold for a lightweight vehicle body component disclosed in a preferred embodiment of the present invention;

[0030] Figure 4 A schematic diagram of the installation position of the top plate of a hot pressing mold for a lightweight vehicle body component disclosed in a preferred embodiment of the present invention;

[0031] Figure 5 A preferred embodiment of the present invention discloses a hot pressing mold for lightweight vehicle body parts Figure 2 Enlarged view of point A in the middle;

[0032] Figure 6 A preferred embodiment of the present invention discloses a hot pressing mold for lightweight vehicle body parts Figure 2 Enlarged view of point B in the middle;

[0033] Figure 7 A schematic diagram of the punch connection structure of a hot pressing die for a lightweight vehicle body component disclosed in a preferred embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the connection structure of the ejector assembly of a hot pressing mold for a lightweight vehicle body component disclosed in a preferred embodiment of the present invention;

[0035] Figure 9This is a schematic diagram of the lifting plate structure of a hot pressing mold for lightweight vehicle body parts disclosed in a preferred embodiment of the present invention.

[0036] Explanation of the numbers in the figure: 1. upper mold assembly; 2. lower mold assembly; 11. upper mold base; 12. pad; 3. punch; 13. through hole; 14. first guide plate; 21. lower mold base; 22. fixed plate; 23. pad; 24. fixed column; 4. die; 25. second guide plate; 26. groove; 27. oblique block; 28. first elastic member; 31. circulating water channel; 32. adjusting plate; 33. pull rod; 34. second elastic member; 35. limiting groove; 36. slider; 37. connecting plate; 38. lever; 5. ejector assembly; 6. punch; 51. support tube; 52. ejector plate; 53. support column; 54. ejector column; 55. support plate; 56. lifting plate; 57. guide groove; 58. reversing groove; 59. third elastic member; 510. ejector plate; 7. ejector rod; 71. positioning block; 72. fourth elastic member. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] Reference Figures 1 to 9 The present embodiment discloses a hot pressing forming mold for lightweight vehicle body parts, including an upper mold assembly 1 and a lower mold assembly 2. The upper mold assembly 1 includes an upper mold base 11, a pad 12 is fixedly mounted on the upper mold base 11, a punch 3 is fixedly mounted on the pad 12, a through hole 13 is opened on the upper mold base 11, a first guide plate 14 is fixedly mounted on the upper mold base 11, and the upper mold base 11 is fixedly mounted on the output end of the elevator on the upper side of the hot press. The output end of the elevator of the hot press drives the upper mold base 11 and the punch 3 to rise and fall, so as to realize the mold opening and closing actions.

[0039] Reference Figures 1 to 5The lower die assembly 2 includes a lower die base 21, a fixed plate 22 is fixedly mounted on the lower die base 21, a pad 23 and a plurality of fixed columns 24 are fixedly mounted on the fixed plate 22, the die 4 is fixedly mounted on the pad 23 and the fixed columns 24, and a second guide plate 25 is fixedly mounted on the lower die base 21. A groove 26 is provided at the bottom of the lower die base 21, and an inclined block 27 is slidably connected in the groove 26. The two ends of the inclined block 27 are inclined, and a first elastic member 28 is installed in the groove 26. One end of the first elastic member 28 is fixedly connected to the groove 26, and the other end is fixedly connected to the inclined block 27. The first elastic member 28 is used to push the inclined block 27 to slide toward the center of the groove 26, and slides with the guide sleeve and the guide column to realize the sliding connection between the upper die base 11 and the lower die base 21. The lower die base 21 is fixedly mounted on the base of the hot press.

[0040] Reference Figure 2 、 Figure 3 and Figure 6 The punch 3 is provided with a circulating water channel 31, which is connected to the water supply equipment and is used for cooling the parts after hot pressing. An adjusting plate 32 is slidably connected to the punch 3, and a number of pull rods 33 are fixedly installed on the punch 3 to be slidably connected to the adjusting plate 32. A second elastic member 34 is mounted on the pull rod 33, and one end of the second elastic member 34 is fixedly connected to the punch 3, and the other end is fixedly connected to the adjusting plate 32. A limiting block is provided at the bottom of the pull rod 33 to prevent the adjusting plate 32 and the pull rod 33 from detaching. The second elastic member 34 is used to push the adjusting plate 32 down to the maximum limit. The lower surface of the adjusting plate 32 at the maximum limit is aligned with the forming surface of the punch 3, that is, the two surfaces have a smooth transition, thereby ensuring that the edge size is stable during hot pressing of the parts to avoid warping or bending problems.

[0041] The punch 3 is provided with a limiting groove 35, to which two sets of sliders 36 are slidably connected. The sliders 36 are provided with inclined surfaces. A connecting plate 37 is fixedly mounted on one side of the slider 36, and a lever 38 is fixedly mounted on the connecting plate 37. By lowering the punch 3 to engage the cavity of the die 4, the flat part is hot-pressed into a part with a certain cavity depth. The bottom surface of the slider 36 is inserted into the limiting groove 35. At this time, the adjustment plate 32 is at its maximum limit position, that is, the adjustment plate 32 and the bottom of the punch 3 are aligned. The slider 36 limits the adjustment plate 32, which can be fixed in position, thereby ensuring the stable shape and size of the part during hot pressing, reducing the risk of warping, and improving the forming accuracy.

[0042] Reference Figure 1 、 Figure 2 、 Figures 4 to 9The mold also includes a pushing assembly 5 and a punch 6. The pushing assembly 5 includes a support tube 51 slidably connected to the fixed plate 22. The support tube 51 passes through the fixed plate 22 and is fixedly installed with a top plate 52. The fixed column 24 passes through the top plate 52 and is slidably connected to the top plate 52. A support column 53 slidably connected to the die 4 is fixedly installed on the top plate 52. The punch 6 is fixedly installed on the top of the support column 53. The punch 6 is annular and inserted into the die 4 for cutting the edges of the parts after hot pressing. When the bottom of the top plate 52 contacts the fixed plate 22, the top of the punch 6 is flush with the top of the die 4, and the inner side of the punch 6 is aligned with the inner edge of the adjustment plate 32.

[0043] It should be noted that the hot pressing molding and the edge ring cutting of the blank of the present invention are carried out asynchronously. The present invention adopts the method of first hot pressing the blank, and then when the temperature of the molding material drops to 110-190°C, the punch 6 performs ring cutting on the edge of the molding material. At this time, the molding material has been partially hardened, avoiding direct ring cutting under high temperature conditions, which is easy to cause deformation or burrs of the cutting edge due to the molding material being too soft, and can reduce edge warping or collapse, improve the edge quality of the molded part, and the blank still retains a certain plasticity within this temperature range, avoiding the brittle cracks that may be caused by punching after complete cooling and the problem of increasing production costs and complexity of the production process by secondary cutting with laser equipment. The temperature detection of the molding material can be carried out by infrared temperature measurement or embedded thermocouple temperature measurement to detect the temperature of the molding material. This is a prior art and will not be described in detail.

[0044] A top post 54 is slidably connected within the support tube 51. A support plate 55, which is slidably connected to the support tube 51, is fixedly mounted on the top post 54. The support plate 55 passes through the support tube 51, and a lifting plate 56 is fixedly mounted on each end. The lifting plate 56 is slidably connected to the first guide plate 14 and the second guide plate 25. The through hole 13 is used for avoiding the lifting plate 56 when it rises. The lifting plate 56 is provided with a guide groove 57 and a reversing groove 58 that are interconnected. The guide groove 57 is located above the reversing groove 58 and is parallel to the movement direction of the top post 54. The shift rod 38 slides in the guide groove 57 and the reversing groove 58 to control the slider 36 to enter or exit the limit groove 35, thereby controlling the limit state of the adjustment plate 32. The top post 54 is fixedly connected to the top rod at the bottom of the hot press. The top rod is the output end of the lifting mechanism at the bottom of the hot press and can drive the top post 54 to move up and down.

[0045] A third elastic member 59 is mounted on the top post 54. One end of the third elastic member 59 is fixedly connected to the support tube 51, and the other end is fixedly connected to the support plate 55. The third elastic member 59 is used to push the support plate 55 against the top of the support tube 51. A push plate 510 is fixedly mounted on the bottom of the support plate 55. The push plate 510 is inserted into the groove 26 and pushes the inclined block 27 to compress the first elastic member 28. During the hot press forming process, the third elastic member 59 is in a compressed state, that is, there is a certain distance between the support plate 55 and the top of the support tube 51, such as at half the length of the support tube 51. This prepares the slider 36 for subsequent movement before the punch 6. At the same time, the pushing force exerted by the third elastic member 59 on the support tube 51 effectively ensures the stability of the end position of the punch 6 during the forming process.

[0046] Reference Figure 2 、 Figure 5 and Figure 8 The mold also includes two sets of ejector pins 7, which pass through the lower die base 21, the fixed plate 22, the ejector plate 52 and the die 4 in sequence from bottom to top. The end of the ejector pin 7 is aligned with the cavity surface of the die 4 and contacts the bottom surface of the part after molding, which is used for auxiliary molding of the bottom surface of the part. A positioning block 71 is fixedly installed on the ejector pin 7, and a fourth elastic member 72 is sleeved on the ejector pin 7. One end of the fourth elastic member 72 is fixedly connected to the lower die base 21, and the other end is fixedly connected to the ejector pin 7. The fourth elastic member 72 is used to drive the ejector pin 7 to move downward so that the positioning block 71 is limited on the fixed plate 22. When the positioning block 71 is limited on the fixed plate 22, the top of the ejector pin 7 is aligned with the cavity surface of the die 4. An avoidance hole is opened on the ejector plate 52. The inner diameter of the avoidance hole is larger than the outer diameter of the positioning block 71 to avoid interference and collision between the positioning block 71 and the ejector plate 52 when the ejector pin 7 rises to push the molded parts.

[0047] This embodiment also discloses a thermoforming process for lightweight vehicle body parts, comprising the following steps:

[0048] S1. Cut the steel plate into blanks of specific contours by laser cutting or blanking process, and heat the blanks to 900-950℃ in a walking beam furnace for 3-5 minutes to fully austenitize the steel.

[0049] S2. The heated blank is clamped by a manipulator or robot and quickly transferred to the cavity of the hot pressing mold;

[0050] S3, the output end of the elevator on the upper side of the hot press drives the punch 3 to descend and cooperate with the die 4 to achieve hot pressing of the blank;

[0051] It should be noted that during the hot pressing process, the bottom of the slider 36 is inserted into the limit groove 35, so that the bottom surface of the adjustment plate 32 is aligned with the bottom surface of the punch 3. In this process, the adjustment plate 32 is used to assist in the forming of the blank, avoiding problems such as warping of the edge of the blank, and ensuring the stability of the edge size of the blank; when the punch 3 descends, the slider 36 follows and descends synchronously, and the shift rod 38 slides in the guide groove 57, and the blank is formed when the punch 3 and the die 4 are in contact. At this time, the shift rod 38 moves to the connection point between the guide groove 57 and the reversing groove 58.

[0052] S4. Cooling water enters the circulating water circuit 31 to cool the molding material. When the molding material temperature is detected to be between 110°C and 190°C, the ejector rod at the bottom of the hot press drives the ejector column 54, the support plate 55, and the lifting plate 56 upward until the support plate 55 contacts the top of the support tube 51. During this process, the third elastic member 59 continues to rebound but remains in a compressed state. The shifting rod 38 moves from the guide groove 57 into the reversing groove 58, driving the connecting plate 37 and the slider 36 to move outward from the limiting groove 35 until the bottom of the slider 36 is clear of the adjustment plate 32.

[0053] S5. The top rod of the hot press continues to drive the top column 54, the support plate 55, the lifting plate 56 and the support tube 51 to rise, and the support tube 51 drives the top plate 52, the support column 53 and the punch 6 to rise, and the punch 6 performs ring cutting on the edge of the molding material; when the punch 6 rises to perform ring cutting, the adjustment plate 32 will follow the rise, and after the ring cutting is completed, the adjustment plate 32 descends under the action of the second elastic member 34, thereby pushing the ring cut material out of the punch 3.

[0054] S6. After the ring cutting is completed, the output end of the elevator at the top of the hot press drives the upper mold assembly 1 and the punch 3 to rise, and the ejector rod at the bottom of the hot press drives the ejector assembly 5 and the punch 6 to continue to descend and compress the third elastic member 59. The push plate 510 follows and descends and pushes the inclined block 27 to compress the first elastic member 28. When the inclined block 27 moves, it pushes the plurality of ejector rods 7 to rise and compress the fourth elastic member 72, thereby ejecting the molding material from the cavity of the die 4, reducing the difficulty of demolding the molding material;

[0055] S7, after demoulding is completed, the ejector rod pushes the ejector column 54 upward, so that the support plate 55 returns to the set position of the support tube 51, preparing for the next thermoforming. The manipulator or robot takes out the cut material and the molded material from the cavity of the die 4 and separates them.

[0056] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. Hot pressing mold for lightweight car body parts, characterized by: The present invention comprises an upper die assembly (1) and a lower die assembly (2) which are slidably connected to each other, wherein a punch (3) is mounted on the upper die assembly (1), and a die (4) is mounted on the lower die assembly (2), an adjustment plate (32) is slidably connected to the punch (3), and a plurality of sliders (36) are slidably connected to the punch (3), and the sliders (36) push the adjustment plate (32) to align with the forming surface of the punch (3); The ejection assembly (5) includes a support tube (51) slidably connected to the lower die assembly (2), a top plate (52) fixedly mounted on the support tube (51), a punch (6) plug-fitted with the die (4) fixedly mounted on the top plate (52), a top column (54) slidably connected in the support tube (51), and a lifting frame slidably connected to the support tube (51) fixedly mounted on the top column (54); The top column (54) drives the lifting frame to rise before the support tube (51) under the driving action, so that the lifting frame rises and the control slider (36) releases the limit of the adjustment plate (32). The rise of the support tube (51) enables the punch (6) to cut the edge of the molding material in the set temperature range.

2. The hot pressing mold for lightweight vehicle body parts according to claim 1, characterized in that: A shifting rod (38) is fixedly mounted on the slider (36), and a guide groove (57) and a reversing groove (58) that are interconnected are provided on the lifting frame, and the shifting rod (38) slides in the guide groove (57) and the reversing groove (58).

3. The hot pressing mold for lightweight vehicle body parts according to claim 1, characterized in that: The top column (54) is provided with a third elastic member (59) for pushing the lifting frame and abutting against the top of the support tube (51).

4. The hot pressing forming die for lightweight vehicle body parts according to claim 1, characterized in that: It also includes a plurality of ejector rods (7) slidably connected to the lower die assembly (2), the ejector rods (7) being inserted into the die (4), the end faces of the ejector rods (7) being aligned with the cavity face of the die (4), and positioning blocks (71) being fixedly mounted on the ejector rods (7); A push plate (510) is fixedly mounted on the bottom of the lifting frame, and the push plate (510) is used to control the push rod (7) to slide in the die (4).

5. The hot pressing mold for lightweight vehicle body parts according to claim 4, characterized in that: The lower die assembly (2) includes a lower die base (21), a slanted block (27) is slidably connected to the lower die base (21), and a first elastic member (28) is installed in the lower die base (21) for pushing the slanted block (27) toward the support tube (51); A fourth elastic member (72) for rebounding the ejector rod (7) is mounted on the lower die base (21).

6. The hot pressing mold for lightweight vehicle body parts according to claim 1, characterized in that: A plurality of pull rods (33) slidably connected to the adjustment plate (32) are fixedly mounted on the punch (3), and a second elastic member (34) for pushing the adjustment plate (32) to align with the forming surface of the punch (3) is mounted on the punch (3).

7. The hot pressing mold for lightweight vehicle body parts according to claim 1, characterized in that: The top of the punch (6) is aligned with the top of the die (4), and the inner side of the punch (6) is aligned with the inner edge of the adjustment plate (32).

8. The hot pressing mold for lightweight vehicle body parts according to claim 1, characterized in that: The lifting frame is slidably connected to the upper mold assembly (1) and the lower mold assembly (2).

9. The hot pressing mold for lightweight vehicle body parts according to any one of claims 1 to 8, characterized in that: The male mold (3) is provided with a circulating water channel (31) for cooling the molding material.

10. A thermoforming process for lightweight vehicle body parts, characterized by: The following steps are involved: S1, heating the blank to 900-950°C and transferring it to the cavity of the hot pressing mold; S2, the hot press drives the punch (3) to descend and cooperate with the die (4) to hot press the blank; S3, when the molding material is cooled to 110-190°C, the hot press drives the ejector assembly (5) to rise and cut the edge of the molding material; S4. After the ring cutting is completed, the hot press drives the ejector assembly (5) to descend and controls the ejector rod (7) to ascend to eject the molding material out of the cavity of the die (4).

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