Cold extrusion pre-treatment die and molding process for airbag component end face using the same

Abstract

The present application relates to the technical field of automobile and rail vehicle part processing, and particularly relates to a cold extrusion pretreatment die and a forming process of an airbag part end face using the same, comprising: a lower die unit and an upper die unit suitable for opening and closing movement; wherein the lower die unit comprises a guide block suitable for limiting the inner contour of a product to be processed, and a necking convex die for pre-extruding the inner edge of an opening of the product to be processed; the upper die unit comprises a necking concave die suitable for limiting the outer contour and the outer edge of the opening of the product to be processed, and a top piece movably arranged in the necking concave die and used for abutting against the outer contour of the product to be processed from the opposite side of the guide block; when the upper die unit and the lower die unit are in a closed die state, the necking convex die is suitable for forming a ring-shaped necking with an inner recess on the inner edge of the opening of the product to be processed. The present application can effectively reduce the processing cost and improve the product forming effect.

Description

Technical Field

[0001] This invention relates to the field of automotive and rail vehicle component processing technology, and in particular to a cold extrusion pretreatment mold and a forming process for the end face of an airbag component using the same. Background Technology

[0002] During the manufacturing process, the edges and end faces of automotive airbag components require surface finishing to meet requirements such as smoothness and burr-free surfaces. Specifically, automotive airbag components are made of high-strength materials with a thickness of 2.0 mm, and are installed using an extrusion friction welding process. Therefore, this product has high requirements for the outer dimensions and roundness of the housing, especially the end face dimensions, which need to be at least 55% of the side wall thickness; otherwise, the weld strength will be affected. Common end face finishing methods include the following:

[0003] The first method is the straight cutting method. This processing method is the simplest, but the cutting edge of the straight cutting die is a fast cutting edge. In order not to scratch the outer shape of the housing when cutting the outer shape, the outer diameter of the die is generally designed to be 0.05 mm larger than the housing. Therefore, a small step will be formed at the root of the cut housing. This cutting method is obviously not suitable for airbag parts.

[0004] The second method is the ring cutting method. This processing method is relatively complicated. The principle is to cut the casing from the side to complete the cutting. This method requires a complex mold structure. For high-strength materials such as airbags, the cutting force required to cut from the side is very large. Moreover, the roundness of the cut product is not good, which cannot meet the requirements of the product.

[0005] The third method is extrusion cutting. This processing method uses a rounded corner at the opening of the cutting die. This structure prevents the product from being scratched when entering the die, thus eliminating the need to manually enlarge the die size to ensure the cut product meets the drawing requirements. However, for this processing method, the extrusion cutting process commonly used in existing technologies is prone to chipping at the cut edge due to the high strength of the materials used in automotive airbag products, as revealed by actual research. Figures 1 to 3As shown, after conventional extrusion cutting, the product exhibits an unsightly fracture surface 102 on its edge end face, and the orifice size is also too large. Furthermore, the effective end face 101 required by the product, upon actual measurement, is only 0.4–0.8 mm, barely reaching 20% ​​of the sidewall material thickness. This fails to meet usage requirements, and insufficient thickness directly increases the risk of subsequent extrusion and welding processes, thus significantly impacting product quality. A common solution is to raise the product's casing by 3 mm and then remove the excess portion through machining to meet processing requirements. However, this method not only increases the required blank diameter, raising material costs, but also adds a machining step, reducing overall processing efficiency. Therefore, for extrusion cutting, existing methods struggle to effectively balance cost reduction and product forming quality. Summary of the Invention

[0006] The first objective of this invention is to provide a cold extrusion pretreatment mold to solve the technical problem of optimizing the forming effect on the end face of the product.

[0007] The second objective of this invention is to provide a molding process for the end face of an airbag component, so as to solve the technical problem of effectively balancing the reduction of processing costs and the effect of product molding.

[0008] The cold extrusion pretreatment die of the present invention is implemented as follows:

[0009] A cold extrusion pretreatment die includes: a lower die unit and an upper die unit adapted for opening and closing movements; wherein

[0010] The lower die unit includes a guide block adapted to limit the inner contour of the product to be processed, and a stop punch for pre-extruding with the inner edge of the opening of the product to be processed.

[0011] The upper mold unit includes a stop die suitable for limiting the outer contour and outer edge of the opening of the product to be processed, and a top piece movably disposed in the stop die for abutting the outer contour of the product to be processed from the opposite side of the guide block.

[0012] When the upper mold unit and the lower mold unit are in the closed state, the stop punch is adapted to form an inwardly recessed annular stop at the inner edge of the opening of the product to be processed.

[0013] In an optional embodiment of the present invention, the upper mold unit further includes a die base for fixing the stop die and an upper ejector rod movably disposed in the die base; wherein

[0014] The upper ejector rod extends from one end toward the lower mold unit at the side end of the die base toward the lower mold unit.

[0015] In an optional embodiment of the present invention, the concave cavity of the stop die has an arc-shaped chamfer formed on the side edge facing the stop punch.

[0016] In an optional embodiment of the present invention, the lower die unit further includes a lower die base for supporting the stop punch and a stripper plate movably disposed on the lower die base for carrying the product to be extruded; wherein

[0017] The unloading plate is movably connected to the lower mold base via a gas spring; and

[0018] The unloading plate has through holes suitable for the guide block and the stop punch to pass through.

[0019] In an optional embodiment of the present invention, the guide block is disposed on one side of the stop punch facing away from the lower die base; and

[0020] The stop die has a through hole, and the lower die base has a support column that passes through the through hole and connects to the guide block.

[0021] The molding process for the end face of the airbag component of the present invention is achieved as follows:

[0022] A molding process for the end face of an airbag component, comprising:

[0023] Step S1: Using the cold extrusion pretreatment mold, an annular stop with an inwardly recessed shape is formed on the inner edge of the opening of the airbag component, so as to reduce the thickness of the connection between the flange on the outer edge of the opening of the airbag component and the airbag component.

[0024] Step S2: Cut the flange at the outer edge of the opening of the airbag component to separate the flange from the airbag component.

[0025] In an optional embodiment of the present invention, the outer diameter of the stop punch of the cold extrusion pretreatment die is larger than the outer diameter of the extrusion cut surface of the outer contour of the airbag component.

[0026] In an optional embodiment of the present invention, the outer diameter of the stop punch of the cold extrusion pretreatment die is 0.4 to 0.6 mm larger than the outer diameter of the extrusion cut surface of the outer contour of the airbag component.

[0027] In an optional embodiment of the present invention, the stop punch of the cold extrusion pretreatment mold used in step S1 is used to extrude the inner edge of the opening of the airbag component, so that the width of the flat end face of the inner edge of the opening of the airbag component is increased to 1.1 to 1.4 mm.

[0028] In an optional embodiment of the present invention, the thickness of the connecting portion is 0.4 to 0.6 mm.

[0029] By adopting the above technical solution, the present invention has the following beneficial effects: The cold extrusion pretreatment mold of the present invention and the forming process of the end face of the airbag component using it, through the cooperation of the stop die and the ejector, as well as the guide block and the stop punch, make the stop punch form an inwardly concave annular stop at the inner edge of the opening of the product to be processed. The forming of this annular stop reduces the thickness of the connection between the flange at the outer edge of the opening of the product to be processed and the product to be processed, and increases the width of the flat end face of the inner edge of the opening of the product to be processed. Thus, the fracture layer at the product cut point basically disappears when the product to be processed is extruded, which can ensure the stability of the product during the production process and ensure that the effective end face of the product meets the requirements after extrusion. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the airbag components before they are extruded and cut.

[0031] Figure 2 This is a schematic diagram of the structure of an airbag component after it has been extruded and cut in the prior art;

[0032] Figure 3 yes Figure 2 A magnified structural diagram of part A;

[0033] Figure 4 This is a schematic diagram of the upper and lower die units of the cold extrusion pretreatment mold in an open state according to an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of the upper and lower die units of the cold extrusion pretreatment mold in an embodiment of the present invention, in a closed state.

[0035] Figure 6 This is a schematic diagram of the stop die of the cold extrusion pretreatment mold according to an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the structure of the airbag component after it has been processed by the cold extrusion pretreatment mold of Example 1;

[0037] Figure 8 yes Figure 7 A schematic diagram of the enlarged structure of part B;

[0038] Figure 9 This is a schematic diagram of the structure of the airbag component after it has been extruded and cut in this embodiment.

[0039] In the diagram: 1. Product to be processed; 2. Ejector plate; 3. Punch fixing plate; 4. Punch pad; 5. Stop punch; 6. Punch fixing seat; 7. Ejector spacer rod; 8. Gas spring; 9. Die fixing plate; 11. Die pad; 10. Upper ejector rod; 12. Stop die; 13. Concave cavity; 131. Arc chamfer; 132. Ejector piece; 14.

[0040] The airbag component 100, effective end face 101, fracture surface 102, semi-circular arc structure 103, annular flange 200, and connecting part 300. Detailed Implementation

[0041] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0042] Example 1:

[0043] Please see Figure 4 and Figure 5 As shown, this embodiment provides a cold extrusion pretreatment mold, including: a lower mold unit and an upper mold unit suitable for opening and closing movements; in terms of the conventional mold usage orientation, the lower mold unit is located below and the upper mold unit is located above. Generally, the mold closing and opening operations of the upper mold unit and the lower mold unit are achieved by the lifting and lowering movement of the upper mold unit.

[0044] To meet the molding requirements of the product 1 to be processed, the lower mold unit generally includes a guide block 5 suitable for limiting the inner contour of the product 1 to be processed, and a stop punch 6 for pre-extruding with the inner edge of the opening of the product 1 to be processed. The upper mold unit includes a stop die 13 suitable for limiting the outer contour and the outer edge of the opening of the product 1 to be processed, and an ejector 14 movably disposed in the stop die 13 for abutting against the outer contour of the product 1 to be processed from the opposite side of the guide block 5. Here, the guide block 5 and the ejector 14 respectively form the positioning of the product 1 to be processed from two different side end faces of the product 1 to be processed, while the stop die 13 forms the limitation of the outer contour of the product 1 to be processed. In this way, the stability of the position of the product 1 to be processed during the operation of the stop die 13 is effectively guaranteed by the cooperation of the stop die 13, the ejector 14 and the guide block 5, ensuring that the product 1 to be processed does not wobble. In this regard, when the upper mold unit and the lower mold unit are in the closed state, the stop punch 6 is adapted to form an inwardly recessed annular stop at the inner edge of the opening of the product 1 to be processed.

[0045] Next, referring to the accompanying drawings, the upper mold unit further includes a mold base for fixing the stop mold 13 and an upper ejector rod 12 movably disposed in the mold base; wherein one end of the upper ejector rod 12 facing the lower mold unit extends from the side end of the mold base facing the lower mold unit. Regarding the mold base, in order to facilitate assembly with the upper ejector rod 12 and the stop mold 13, the mold base can be an assembly formed by multiple structures, which at least includes a mold fixing plate 11 and a mold pad plate 10 connected together; the upper ejector rod 12 and the mold fixing plate 11 have a movable fit structure, and an elastic structure, such as, but not limited to, a spring, is provided on the side of the upper ejector rod 12 facing away from the lower mold unit, so that the upper ejector rod 12 can push the spring, and the upper ejector rod 12 can be partially retracted into the mold base, thereby meeting the mold closing requirements of the upper mold unit and the lower mold unit.

[0046] Based on the above structure, furthermore, for the ejector 14 which is movably connected to the concave cavity 131 of the stop die 13, an elastic structure, such as but not limited to a spring, is provided on the side of the ejector 14 facing away from the lower die unit, so that the ejector 14 can push the spring and move towards the side facing away from the lower die unit to provide clearance space for the product to be processed 1 to enter the stop die 13, and the spring on the side of the ejector 14 ensures the pushing force of the ejector 14 on the product to be processed 1.

[0047] In addition, it is necessary to explain that, on the one hand, considering the rapid fit between the concave cavity 131 of the stop die 13 and the product 1 to be processed, and on the other hand, to improve the fitting effect between the stop die 13 and the outer contour of the product 1 to be processed, and to avoid interference at the end corner of the stop die 13 due to the precision of the mold, the concave cavity 131 of the stop die 13 used in this embodiment has an arc-shaped chamfer 132 formed on the side edge of the stop punch 6.

[0048] Next, let's discuss the lower die unit: The lower die unit used in this embodiment also includes a lower die base for supporting the stop punch 6 and a stripper plate 2 movably disposed on the lower die base for carrying the product to be extruded; wherein the stripper plate 2 is movably connected to the lower die base via a gas spring 9; and the stripper plate 2 has through holes suitable for the guide block 5 and the stop punch 6 to pass through. Regarding the punch base here, in order to facilitate assembly with the gas spring 9 and the stop punch 6, the punch base can be an assembly formed by multiple structures, which at least includes a punch fixing plate 3 and a punch pad 4 that are mated and connected. Here, a punch fixing seat 7 is also provided between the punch fixing plate 3 and the stop punch 6.

[0049] Based on the above, furthermore, a stripper spacing rod 8 is provided between the stripper plate 2 and the punch base. One end of the stripper spacing rod 8 is fixed on the punch base, and the other end is movably connected to the stripper plate 2. During the mold closing process of the upper mold unit and the lower mold unit, the end of the stripper spacing rod 8 facing away from the punch base can be inserted into the die base.

[0050] In addition, it is necessary to explain that the guide block 5 is located on the side of the stop punch 6 facing away from the lower die base; and the stop die 13 is provided with a through hole, and the lower die base is provided with a support column that passes through the through hole and connects to the guide block 5.

[0051] For the cold extrusion pretreatment mold used in this embodiment:

[0052] As the upper ejector rod 12 of the upper die unit moves downward, when it contacts the stripper plate 2, the elastic force on the upper ejector rod 12 is greater than the elastic force of the gas spring 9 on one side of the stripper plate 2. This causes the stripper plate 2 to overcome the upward unloading force of the gas spring 9, and the upper ejector rod 12 pushes the stripper plate 2 downward. As a result, the product to be processed 1, which is carried on the stripper plate 2, moves downward with the stripper plate 2 under the action of gravity until it is fitted onto the guide block 5. The upper die unit continues to move downward. After the ejector 14 presses down on the product to be processed 1, after the product to be processed 1 enters the stop die 13, the product to be processed 1 continues to move downward with the upper die unit. After the stripper plate 2 contacts the lower die base, it stops moving. Then the upper die unit continues to move downward, and the upper ejector rod 12 overcomes the elastic force of its corresponding elastic structure and moves upward, so that the product to be processed 1, which is pressed down by the back stop die 13, contacts the stop punch 6, completing one cold extrusion pretreatment.

[0053] Example 2:

[0054] Please see Figures 4 to 9 As shown, based on the cold extrusion pretreatment mold of Example 1, this embodiment provides a forming process for the end face of an airbag component 100. It should be noted that the airbag component 100 involved in this embodiment is generally a cylindrical shell with an opening at one end. Before extrusion cutting, an annular flange 200 is connected to the edge of the opening of the cylindrical shell. In this embodiment, the forming process for the end face of the airbag component 100 ultimately requires separating the annular flange 200 from the airbag component 100 and reducing the probability of a fracture surface 102 appearing at the separation surface. Furthermore, it is necessary to note that, in conjunction with a conventional airbag component 100, the inner corner edge of its opening also forms a semi-circular arc structure 103.

[0055] To achieve the above effects, this embodiment employs the following method, which includes:

[0056] First, step S1: using the cold extrusion pretreatment mold of Example 1, an annular stop with an inwardly recessed shape is formed on the inner edge of the opening of the airbag component 100, so as to reduce the thickness of the connection portion 300 between the flange on the outer edge of the opening of the airbag component 100 and the airbag component 100.

[0057] In this step, it should be noted that the outer diameter of the stop punch 6 of the cold extrusion pretreatment die is larger than the outer diameter of the extrusion cut surface of the outer contour of the airbag component 100.

[0058] More specifically, the outer diameter of the stop punch 6 of the cold extrusion pretreatment die is 0.4 to 0.6 mm larger than the outer diameter of the extrusion cut surface of the airbag component 100. This allows some material from the annular flange 200 to be extruded into the stop die 13 through the stop punch 6 during the cold extrusion pretreatment process, thereby filling the gap in the opening material. Of course, the difference in outer diameter between the two should not be too large, otherwise the opening diameter of the airbag component 100 will be too large, thus affecting the outer diameter of the airbag component 100.

[0059] Based on the above, step S1 of this embodiment, by compressing the inner edge of the opening of the airbag component 100, transforms the semi-circular arc structure 103 of the inner corner edge of the opening of the airbag component 100 into a circular arc segment, and reduces the thickness of the cut surface, thereby changing the length of the fracture layer. Since the width of the flat end face (effective end face 101) of the inner edge of the opening of the airbag component 100 is equal to the thickness of the sidewall material, the length of the fracture surface 102, and the width of the semi-circular arc structure 103, step S1 of this embodiment can directly and effectively increase the width of the effective end face 101 of the opening of the airbag component 100.

[0060] Furthermore, it should be noted that the stop punch 6 of the cold extrusion pretreatment die used in step S1 is used to extrude the inner edge of the opening of the airbag component 100, thereby increasing the width of the flat end face of the inner edge of the opening of the airbag component 100 to 1.1–1.4 mm. Moreover, the thickness of the connecting portion 300 is 0.4–0.6 mm. Under this structure, the effective end face 101 width is stable and suitable for mass production. Specifically, when the thickness of the connecting portion 300 is less than 0.3 mm, the corresponding width of the flat end face of the inner edge of the opening of the airbag component 100 is 1.3–1.6 mm. Although the effective end face 101 is maximized at this time, the airbag component 100 is prone to detaching from the annular flange 200, thus failing to meet the requirements of mass production. Conversely, when the thickness of the connecting portion 300 is greater than 0.8 mm, the corresponding width of the flat end face of the inner edge of the opening of the airbag component 100 is less than 0.9 mm, thus minimizing the effective end face 101.

[0061] The next step is step S2: the connection 300 between the flange at the outer edge of the opening of the airbag component 100 and the airbag component 100 is extruded and cut to separate the flange from the airbag component 100. It should be noted that for the extrusion and cutting operation between the flange and the airbag component 100 in this step, any mature extrusion die in the prior art can be used, and this embodiment does not make an absolute limitation on this.

[0062] In summary, for the molding process of the end face of the airbag component 100 in this embodiment, since it is no longer necessary to machine and remove the waste edges, the blank of the product can be reduced. Specifically, the blank can be reduced by 2.0 mm on one side, thereby reducing the overall material loss of the airbag component 100 by 8%, thereby reducing the production cost of the product.

[0063] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0064] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0065] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

Claims

1. A cold extrusion pretreatment die, characterized in that, include: Lower mold unit and upper mold unit suitable for opening and closing motion; in The lower die unit includes a guide block adapted to limit the inner contour of the product to be processed, and a stop punch for pre-extruding with the inner edge of the opening of the product to be processed. The upper mold unit includes a stop die suitable for limiting the outer contour and outer edge of the opening of the product to be processed, and a top piece movably disposed in the stop die for abutting the outer contour of the product to be processed from the opposite side of the guide block. When the upper mold unit and the lower mold unit are in the closed state, the stop punch is adapted to form an inwardly recessed annular stop at the inner edge of the opening of the product to be processed; the concave cavity of the stop die has an arc-shaped chamfer on the side edge facing the stop punch. The upper mold unit also includes a die base for fixing the stop die and an upper ejector rod movably disposed in the die base; one end of the upper ejector rod extending out of the side end of the die base facing the lower mold unit. The lower die unit also includes a lower die base for supporting the stop punch and a stripper plate movably disposed on the lower die base for carrying the product to be extruded. The stripper plate is movably connected to the lower die base via a gas spring; the stripper plate has a through hole suitable for the guide block and the stop punch to pass through; the guide block is located on the side of the stop punch facing away from the lower die base.

2. The cold extrusion pretreatment die according to claim 1, characterized in that, The stop die has a through hole, and the lower die base has a support column that passes through the through hole and connects to the guide block.

3. A molding process for the end face of an airbag component, characterized in that, include: Step S1: Using the cold extrusion pretreatment mold as described in claim 1 or 2, an annular stop with an inwardly recessed shape is formed on the inner edge of the opening of the airbag component, so as to reduce the thickness of the connection between the flange at the outer edge of the opening of the airbag component and the airbag component. Step S2: Cut the flange at the outer edge of the opening of the airbag component to separate the flange from the airbag component.

4. The molding process for the end face of the airbag component according to claim 3, characterized in that, The outer diameter of the stop punch of the cold extrusion pretreatment die is larger than the outer diameter of the extrusion cut surface of the outer contour of the airbag component.

5. The molding process for the end face of the airbag component according to claim 4, characterized in that, The outer diameter of the stop punch of the cold extrusion pretreatment die is 0.4 to 0.6 mm larger than the outer diameter of the extrusion cut surface of the airbag component.

6. The molding process for the end face of the airbag component according to any one of claims 3 to 5, characterized in that, The stop punch of the cold extrusion pretreatment mold used in step S1 is used to extrude the inner edge of the opening of the airbag component, so that the width of the flat end face of the inner edge of the opening of the airbag component is increased to 1.1 to 1.4 mm.

7. The molding process for the end face of the airbag component according to claim 6, characterized in that, The thickness of the connecting part is 0.4 to 0.6 mm.

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