Drawing die structure

Abstract

The utility model relates to a drawing die structure, which belongs to the technical field of automobile dies and comprises an upper die holder, a lower die holder, a blank holder, a male die and a female die. The female die is installed at the bottom of the upper die base, and the male die is arranged in the middle of the top face of the lower die base and is locked and fixed through a plurality of locking block screws arranged on the side face of the male die in a surrounding mode. The blank holder comprises a blank holder body and a blank holder molded surface; the blank holder body is arranged on the outer side of the male die in a sleeving mode and installed on the lower die base, and the blank holder molded surface surrounds the male die and is installed on the blank holder body. And the female die is positioned above the male die and the blank holder molded surface. The upper die base, the lower die base and the blank holder body are reused under similar parts of the same type, only the molded surfaces of the male die, the female die and the blank holder need to be switched according to the parts, the one-time tool input cost of die development is reduced, and the development period is shortened.

Description

Technical Field

[0001] This utility model relates to the field of automotive mold technology, and in particular to a drawing die structure. Background Technology

[0002] Currently, competition in the domestic automotive market is becoming increasingly fierce. With the exception of a very few manufacturers, the total sales volume of a single model's product lifecycle is rapidly decreasing for most OEMs. OEMs are accelerating the pace of new model development and model updates, leading to increasingly significant cost reductions in new model development and manufacturing. Stamping dies and tooling account for the majority of tooling costs and play a dominant role in controlling overall vehicle development and manufacturing costs.

[0003] In terms of current automotive stamping manual drawing dies, dies are generally divided into four main parts: upper die, lower die, punch, and blank holder. The main weight of the die is generated by these four parts. During the development of stamping dies for different car models, the cost of castings and processing for each newly developed die is very high. However, due to increased competition, the production volume of single-type parts for many car models is not large. The repetitive development of dies for similar parts of the same type and size results in a significant waste of die development costs.

[0004] Moreover, in the traditional development model, molds for different OEMs are basically made in the form of multiple complete process molds for one part. Because of the different OEM projects, the mold factory needs to develop them separately according to the requirements of the delivered molds, and finally hand over the molds. The overall mold making process is large and the molds are heavy. With the rise of small-batch customized business, many OEMs no longer require the handover of molds, but only need to provide stamped products. If complete process molds are still developed separately according to the mold requirements of different projects, it will result in a waste of development costs for both OEMs and mold factories. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides a drawing die structure. Based on the existing drawing die, by splitting the drawing die core part, the traditional drawing die base or die frame is standardized. For drawing dies of the same type of parts in the same project or different projects, only the die core part needs to be developed. This achieves the effect of reusing the upper and lower die base bodies, the blank holder body, and the positioning guide parts, effectively reducing the material costs of various components in the early stage of die investment, saving die development and manufacturing costs, reducing one-time investment in tooling, saving development and design, processing and manufacturing cycles, saving on-site debugging workload, and saving warehouse space, etc.

[0006] To achieve the above objectives, the specific technical solution of this utility model is as follows:

[0007] A drawing die structure, the drawing die structure comprising an upper die base, a lower die base, a blank holder, a punch, and a die;

[0008] The concave mold is installed at the bottom of the upper mold base, and the punch is placed in the middle of the top surface of the lower mold base and is fixed by a plurality of locking block screws arranged around the side of the punch;

[0009] The pressure ring includes a pressure ring body and a pressure ring profile; the pressure ring body is sleeved on the outside of the punch and mounted on the lower die base, and the pressure ring profile is mounted around the punch on the pressure ring body; the die is located above the punch and the pressure ring profile.

[0010] Furthermore, the pressure ring also includes a backing plate, and the pressure ring body and the pressure ring profile are separated by the backing plate.

[0011] Furthermore, the pad has an L-shaped backrest and a pressing surface around its sides. The pad is inserted from the bottom of the pressing ring body between the pressing ring body and the pressing ring surface, and is initially positioned and secured by the L-shaped backrest and pressing surface of the pad, and then fixed by screws.

[0012] Furthermore, the size of the mounting surface of the pad is fixed, the size of the outer ring of the pad is designed according to the parts within the predetermined range of different projects, and the size of the inner ring of the pad is designed according to the parting line clearance of different projects.

[0013] Furthermore, the pressure ring is initially positioned around its perimeter using an L-shaped backrest with a backrest key. The backrest key is inserted between the pressure ring body and the pressure ring surface and secured with screws.

[0014] Furthermore, the pressure ring body is provided with a balance top rod at each of the four corners around its perimeter; the pressure ring body is also provided with a positioning groove at each of the four corners that is perpendicular to the part sheet, and a material support positioning device is installed in the positioning groove.

[0015] Furthermore, the lower die base has multiple positioning keys on its top surface, and the bottom of the punch has a keyway hole corresponding to the positioning keys; when the punch is installed, the positioning keys are embedded in the keyway hole.

[0016] Furthermore, the upper mold base and the cavity mold adopt a separate structure; the bottom surface of the upper mold base has a recessed area in the middle, and the upper mold base is provided with upper fixing holes spaced around the recessed area; the cavity mold is placed in the recessed area and is secured by reverse screws through the upper fixing holes.

[0017] Furthermore, the initial positioning of the cavity die and the upper die base is achieved by using a backrest and clamping key for clamping.

[0018] Furthermore, safety bolts are installed at the four corners of the recessed area of ​​the upper mold base, and the upper mold base is connected to the cavity mold through the safety bolts.

[0019] The beneficial effects of this utility model are:

[0020] This utility model of a drawing die structure is used for the development of drawing dies for similar parts of different car models. It can reuse the upper and lower die bases, the blank holder body and the positioning guide, effectively reducing the overall weight of the die, effectively reducing the overall development cost of the die, reducing long-term tooling investment, accelerating the development cycle, and effectively overcoming the disadvantages of high die material cost and long design cycle in the prior art.

[0021] The pressure ring of this utility model adopts a split structure. While the main body of the pressure ring is shared, it also takes into account the needs of adjusting and changing the parting line of the pressure ring of different parts. The mold core of the middle surface of the mold can be adjusted according to the actual size of the part, so as to realize the sharing of the main body of the pressure ring between different parts and increase the sharing ratio of the overall mold structure.

[0022] This invention achieves the sharing of three main casting components for drawing dies: the upper die holder, the lower die holder, and the blank holder ring. It also enables the reuse of over 70% of the original die's standard and non-standard parts, saving on die structure procurement costs. Furthermore, the shared components account for over 60% of the weight, saving on casting material costs and reducing subsequent processing costs for multiple uses. It is expected to shorten the drawing die development cycle by more than two days, reduce die storage space by approximately 50%, and reduce die design time by approximately 60-70%. In addition, this invention standardizes the manufacturing of shared components; the more frequently they are reused in different projects and dies, the more significant the overall die development and manufacturing cost reduction will be, aligning with current trends in stamping die development. Attached Figure Description

[0023] Figure 1 This is an overall structural diagram of the iron front guard body drawing common upper and lower die bases and pressure ring of this utility model;

[0024] Figure 2 This is a cross-sectional view of the iron front guard body drawing common upper and lower die bases and pressure ring structure of this utility model;

[0025] Figure 3 This is a schematic diagram of the lower die holder and punch structure in this utility model;

[0026] Figure 4 This is a top view of the lower mold base of this utility model;

[0027] Figure 5 This is a top view of the intermediate pressure edge ring structure of this utility model;

[0028] Figure 6This is a bottom view of the pressure ring structure of this utility model;

[0029] Figure 7 This is a schematic diagram of the upper mold base structure in this utility model;

[0030] Figure 8 This is a bottom view of the upper mold base in this utility model.

[0031] Wherein: 1-Upper mold base, 2-Lower mold base, 3-Pressure ring body, 4-Punch, 5-Die, 6-Pressure ring profile, 7-Backing plate, 8-Bottom block, 9-Stroke limit bolt, 10-Positioning key, 14-Lower fixing hole, 15-Ejector rod through hole, 16-First wear-resistant plate, 17-Balance block, 18-Backrest key, 19-Positioner, 20-Ejector rod pad, 21-Fixed block, 22-Clamping key, 23-Second wear-resistant plate, 24-Upper fixing hole, 25-Safety bolt, 26-Locking block. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of this application, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] The directional terms such as above, below, left, right, front, and back used in this application are based on the positional relationships shown in the attached drawings. Different attached drawings may result in different positional relationships, therefore they should not be interpreted as limitations on the scope of protection.

[0034] In this utility model, the terms "installation," "connection," "interlocking," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a connection that allows communication, a direct connection, or an indirect connection through an intermediate medium. They can also refer to the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0035] This embodiment describes a drawing die structure, which is mainly used in the development of stamping, drawing and casting dies for automotive sheet metal. By switching the core area on the same standard die base, it effectively solves the problem of stamping and drawing die development for similar parts of different projects and models.

[0036] This embodiment uses a small-batch customized project for an OEM (Original Equipment Manufacturer) involving a steel front bumper drawing die as an example to illustrate the solution. The steel front bumper part is made of DC06 steel and has a thickness of 2mm. During the die development and design process, the drawing die is designed to be shared by the upper and lower die bases and the main body of the pressure ring. Subsequent projects can reuse the main body of the die, only requiring adjustment of the die core in the middle profile of the die according to the actual size of the part, resulting in a good cost reduction effect.

[0037] Specifically, such as Figure 1 and Figure 2 As shown, the drawing die structure includes an upper die base 1, a lower die base 2, a blank holder ring, a punch 4, and a die 5. The die 5 is installed at the bottom of the upper die base 1, and the punch 4 and the blank holder ring are respectively installed on the lower die base 2, with the blank holder ring sleeved on the outside of the punch 4. The upper die base 1 and the die 5 move from top to bottom relative to the lower die base 2 and the punch 4 to press the material on the punch 4 and the blank holder ring.

[0038] In this embodiment, the lower mold base 2 and the punch 4 adopt a split structure, and the two can be made using HT300 to reduce the overall material cost.

[0039] like Figure 3 and Figure 4 As shown, the punch 4 is placed in the middle of the top surface of the lower die base 2. Multiple lower fixing holes 14 are arranged on the top surface of the lower die base 2 in a manner that is sparse in the middle and dense at both ends. Multiple locking blocks 26 are arranged around the side of the punch 4. The locking blocks 26 are in close contact with the punch 4. The mounting holes on the locking blocks 26 are vertically aligned with the corresponding lower fixing holes 14. The locking blocks 26 are fixed to the lower die base 2 by screws, which can prevent the punch 4 from moving back and forth or left and right.

[0040] To ensure accurate positioning and installation of the punch 4, positioning keys 10 are provided on the upper surface of the lower die holder 2 along the horizontal and vertical axes of the lower die holder 2. The mounting holes on the positioning keys 10 are vertically aligned with the corresponding lower fixing holes 14. The positioning keys 10 are installed on the lower die holder 2 by screws. The bottom of the punch 4 has a keyway hole corresponding to the positioning keys 10. When the positioning keys 10 are embedded in the keyway hole, the punch 4 is accurately positioned on the lower die holder 2. The setting of the positioning keys 10 facilitates the punch 4 to be quickly aligned and positioned on the lower die holder 2, thereby improving the installation efficiency of the punch 4.

[0041] Two locating keys 10 are arranged along the horizontal axis along the length of the lower die base 2. These two locating keys 10 are symmetrically installed on the left and right sides of the upper surface of the lower die base 2 with the vertical axis as the center. One locating key 10 is installed along the vertical axis along the width of the lower die base 2 (maximum one more, depending on the actual situation). The screws securing the punch 4 are arranged in multiple rows. Two locating pins can also be diagonally arranged at the bottom of the punch 4. Corresponding locating pin mounting holes are provided on the upper surface of the lower die base 2 (initially, more locating pin mounting holes can be arranged on the lower die base 2 to facilitate the installation of punches 4 of different types and sizes later), facilitating the quick positioning and installation of the punch 4. The dimensions of the lower die base 2 accommodate the installation of punches 4 of different sizes within a certain range, facilitating the switching of punches 4 to suit the drawing of similar parts within a certain specification range.

[0042] In this embodiment, the lower mold base 2 is provided with multiple ejector pin through holes 15 in the form of full ejector pins. The multiple ejector pin through holes 15 are arranged in a matrix. When drawing similar parts of different projects within a certain specification range, the corresponding number of ejector pins can be arranged in the ejector pin through holes 15 at the corresponding positions according to the actual working conditions, so as to provide a force source for part forming and demolding.

[0043] In this embodiment, multiple bottom blocks 8 are evenly distributed around the top surface of the lower mold base 2. When arranging them, they are staggered as much as possible from the press T-slots to limit the movement of the upper mold base 1 downward and the installation of the pressure ring, so as to prevent excessive compression of the empty part of the lower mold base 2 and prevent the upper mold base 1, pressure ring, lower mold base 2 and other castings from deforming.

[0044] Symmetrical travel limit bolts 9 are provided on the front and rear sides of the top surface of the lower mold base 2 to limit the vertical movement of the pressure ring, ensuring that the pressure ring part of the mold is not carried up by the upper mold base 1, thus playing a safety protection role.

[0045] In addition, the left and right ends of the top surface of the lower mold base 2 are respectively provided with upwardly extending and front-backed lower guide legs for positioning and guiding with the pressure ring body 3. The outer sides of the lower guide legs are connected by connecting plates, which serve as transport connection and protection. Between the front and rear lower guide legs, there are two rows of bottom blocks 8. The outer row of bottom blocks 8 is used to limit the maximum downward stroke of the corner of the pressure ring body 3 when it presses down on the lower mold base 2 to maintain balance. The inner row of bottom blocks 8 on the lower mold base 2 corresponds to the balance blocks 17 on the top surface of the pressure ring body 3, so that the force when the pressure ring body 3 is formed to the bottom is supported to the maximum extent and transmitted to the lower machine table, which provides the best protection for the lower mold base 2 and the pressure ring body 3, facilitates the fitter to adjust the quality of the parts, and limits the maximum downward stroke of the pressure ring body 3.

[0046] In addition, the bottom of the lower die holder 2 is provided with positioning mounting holes and keyway holes. The positioning mounting holes match the positioning mounting holes on the lower machine platform, and the keyway holes match the positioning keys on the lower machine platform. By fixing the positioning guide pins and positioning keys on the positioning mounting holes, the lower die holder 2 can be quickly aligned and positioned and installed on the lower machine platform, thereby improving the installation efficiency of the drawing die structure on the lower machine platform.

[0047] The pressure ring in this embodiment is as follows: Figure 5 , Figure 6 The diagram shows a pressure ring body 3, a pressure ring profile 6, and a backing plate 7. The pressure ring body 3 and pressure ring profile 6 are separate structures. The pressure ring body 3 is made of HT300 material, and the pressure ring profile 6 is made of MoCr material. Due to the price difference between the two materials, the casting cost can be significantly reduced. The pressure ring body 3 has a recessed area in the middle, which is hollow. The pressure ring body 3 is fitted onto the lower die base 2 on the outside of the punch 4. The pressure ring profile 6 is installed around the punch 4 on the recessed area of ​​the pressure ring body 3. Initially, the pressure ring profile 6 is positioned around the perimeter using the L-shaped backrest of the backrest key 18. Then, the backrest key 18 is used to squeeze into the gap between the pressure ring body 3 and the pressure ring profile 6, and the front screws are used to secure the pressure ring profile 6. A front pin is used for precision positioning to connect the pressure ring profile 6 and the pressure ring body 3. In this embodiment, the inner cavity size of the pressure ring body 3 meets the length, width, and height requirements of the pressure ring profile 6 for parts within a certain specification range, so as to switch between using the same pressure ring body 3 when drawing parts within a certain specification range. The pressure ring profile 6 is set according to the edge shape of the part. The installation position of the backrest key 18 and different specifications meet the installation requirements of the pressure ring profile 6 for different projects within the specified range, realizing the switching of the pressure ring profile 6.

[0048] In this drawing die structure, a shim 7 is provided between the blank holder body 3 and the blank holder profile 6 for separation. The shim 7 is a separate piece due to the different parting line sizes and positions of the punches 4 for different parts. When drawing the same type of parts for different projects, the parting line of the punches 4 can be adjusted by changing the shim 7 according to the parts. The shim 7 has an L-shaped backrest and a clamping surface around its sides. The shim 7 is inserted from the bottom of the blank holder body 3 between the blank holder body 3 and the blank holder profile 6, and is initially positioned and locked by the L-shaped backrest and the clamping surface, and then fixed by screws. The shim 7 has bosses corresponding to the ejector pin and the stop block 21 respectively. The lower die base 2 has a coaxial ejector pin boss clearance hole, and the ejector pin pad 20 is installed on the ejector pin boss to transmit the output force of the ejector pin of the lower die base upward. A dead block 21 is installed on the corresponding boss on the base plate 7. Adjustment shims can be set on the boss of the dead block to adjust the clearance around the parting line of the pressure ring to the bottom, so as to achieve force balance when the mold is bottomed. The size of the mounting surface of the base plate 7 is basically determined in the early design. The size of the outer ring of the base plate 7 is based on the part design within the predetermined range of different projects. The size of the inner ring of the base plate 7 can be designed to avoid gaps in the parting line of different projects, so as to realize the switching of the base plate 7.

[0049] In this embodiment, multiple dead blocks 21 are evenly spaced around the bottom surface of the pressure ring body 3, and the dead blocks 21 correspond to the balance blocks 17 on the top surface of the pressure ring body 3, which are used to limit the pressure ring body 3 when it is fully installed under the upper mold base 1. The arrangement of the dead blocks 21 is staggered from the T-slot of the press to ensure that the mold is balanced under the force.

[0050] The pressure ring body 3 has a longitudinal balancing rod at each of its four corners to prevent uneven stress on the pressure ring and maintain balance. The pressure ring body 3 has positioning grooves for material support locators 19 on its front, back, left, and right sides. The length of the positioning grooves is perpendicular to the sheet metal. The material support locators 19 are installed in the positioning grooves with screws to position the drawn sheet metal, preventing sagging and instability after initial sheet metal placement. The material support locators 19 are adjustable; the mounting holes for the screws in the positioning grooves are elongated slots in the front-back direction, allowing for adjustment of the material support locator 19's position to accommodate dimensional fluctuations within the specified range, thus better meeting the requirements for drawing parts within the specified range.

[0051] Multiple balance blocks 17 are spaced around the top surface of the blank holder body 3 to ensure balanced and stable pressing, and improve the stability of drawing. The balance blocks 17 are evenly arranged and do not interfere with the blank holder surface 6 within the specified range of similar parts in different projects, ensuring that the drawing die can be properly debugged and used.

[0052] The left and right ends of the pressure ring body 3 are respectively provided with guide structures. The internal dimensions of the guide structures are adapted to the dimensions of the upper guide legs of the upper mold base 1, and the external dimensions of the guide structures are adapted to the dimensions between the front and rear lower guide legs of the lower mold base 2. When the pressure ring is pressed onto the lower mold base 2, the guide structures at the left and right ends of the pressure ring body 3 are inserted between the front and rear lower guide legs of the lower mold base 2. The pressure ring body 3 has first wear-resistant plates 16 installed at the middle of the inner end of the guide structure and on the front and rear sides of the guide structure (i.e., the four corners of the pressure ring body 3). When the pressure ring body 3 moves relative to the lower mold base 2, it is guided by the first wear-resistant plates 16 at the four corners. When the upper mold base 1 presses down on the pressure ring body 3, it is guided by the upper guide legs and the first wear-resistant plates 16 and second wear-resistant plates 23 at the inner end of the pressure ring guide structure. The size of the first wear-resistant plates 16 on the side guide structures of the lower mold base 2 and the pressure ring body 3, which have a large stroke and irregular shape, meets the guiding requirements of large stroke molds.

[0053] In this embodiment, the upper mold base 1 and the cavity mold 5 adopt a split structure. The upper mold base 1 is made of HT300 material, and the cavity mold 5 is made of MoCr material. Due to the price difference between the two materials, the casting cost can be greatly reduced. Figure 7 , Figure 8 As shown, the upper mold base 1 has a recessed area in the center of its bottom surface. Upper fixing holes 24 are spaced around the perimeter of this recessed area. The die 5 is placed within this recessed area. The die 5 is initially positioned by a backrest and clamping keys 22 between its perimeter and the upper mold base 1. It is then secured with screws through the upper fixing holes 24 and finely positioned with pins through the upper fixing holes 24. In this embodiment, securing the die 5 from the back helps to reduce its size, and the screw and pin positions can be arranged according to the positions of the fixing holes 24 when switching die 5 later. The recessed area of ​​the upper mold base 1 in this embodiment can accommodate die 5s within the specified range for different projects. Initial positioning of die 5s of different specifications can be achieved by replacing clamping keys 22 of different sizes. In other words, the external size of the die 5 within the specified range for different projects can be designed according to the space available for the die 5 to meet installation requirements.

[0054] In this embodiment, safety bolts 25 are fixed at the four corners of the recessed area of ​​the upper mold base 1. The upper mold base 1 and the die 5 are connected by the safety bolts 25, which not only ensures the safety of the connection between the two, but also facilitates the precise positioning and locking of the two. In this embodiment, the position of the safety bolts 25 remains unchanged. The die 5 that is replaced later can only be set according to the shape and size of the concave surface of the die 5 according to the shape of the corresponding part, which reduces the redesign of the outside of the die 5, thereby reducing some design content and ensuring the precise installation of the die 5.

[0055] In this embodiment, the upper mold base 1 has downwardly extending upper guide legs at the bottom center of both the left and right ends. Second wear-resistant plates 23 are installed on the front and rear sides of the upper guide legs. When the upper mold base 1 presses down the pressure ring 3, the upper guide legs are inserted into the guide structures at both ends of the pressure ring and pressed together with the pressure ring into the space between the front and rear lower guide legs of the lower mold base 2, and guided by the first wear-resistant plate 16 and the second wear-resistant plate 23.

[0056] In this embodiment, the first wear-resistant plate 16 and the second wear-resistant plate 23 not only serve as guides, but also increase the wear resistance of the pressure ring, the upper die holder 1 and the lower die holder 2, so as to prevent the pressure ring, the upper die holder 1 and the lower die holder 2 from being severely worn at the joint due to long-term drawing operations, which would make it impossible to guarantee vertical downward pressure and thus affect the quality of the drawn product.

[0057] In addition, in this embodiment, lifting bolts are provided at the left and right ends of the front and rear sides of the pressure ring, the upper die holder 1 and the lower die holder 2, so as to facilitate the installation of the drawing die structure by lifting.

[0058] The drawing die structure of this embodiment does not require the production of a die base and pressure ring for each part. The shared use of the upper die base 1, lower die base 2 and pressure ring body 3 can significantly reduce the cost of die development and use, thereby minimizing the initial investment in tooling and making full use of resources. This can effectively enhance the competitiveness of enterprises and meet the deep-seated development needs of the automotive flexible customization industry.

[0059] Although the principles of this utility model have been described in detail above with reference to preferred embodiments, those skilled in the art should understand that the above embodiments are merely illustrative explanations of the implementation of this utility model and are not intended to limit the scope of this utility model. The details in the embodiments do not constitute a limitation on the scope of this utility model. Any obvious changes, such as equivalent transformations or simple substitutions, based on the technical solution of this utility model without departing from its spirit and scope fall within the protection scope of this utility model.

Claims

1. A drawing die structure, characterized in that, The drawing die structure includes an upper die base (1), a lower die base (2), a blank holder, a punch (4), and a die (5); The concave mold (5) is installed at the bottom of the upper mold base (1), and the punch (4) is placed in the middle of the top surface of the lower mold base (2), and is fixed by screws of multiple locking blocks (26) arranged around the side of the punch (4); The pressure ring includes a pressure ring body (3), a pressure ring profile (6), and a pad (7); the pressure ring body (3) is fitted on the outside of the punch (4) and mounted on the lower die base (2); the pressure ring profile (6) is mounted on the pressure ring body (3) around the punch (4); the pad (7) has an L-shaped backrest and a pressing surface around its side; the pad (7) is inserted from the bottom of the pressure ring body (3) between the pressure ring body (3) and the pressure ring profile (6), and is initially positioned and locked by the L-shaped backrest and pressing surface of the pad (7); the die (5) is located above the punch (4) and the pressure ring profile (6).

2. The drawing die structure according to claim 1, characterized in that, The mounting surface size of the pad (7) is fixed. The outer ring size of the pad (7) is designed according to the parts within the predetermined range of different projects in the later stage. The inner ring size of the pad (7) is designed according to the parting line clearance of different projects.

3. The drawing die structure according to claim 1, characterized in that, The pressure ring surface (6) is initially positioned around the L-shaped backrest of the backrest key (18). The backrest key (18) is squeezed between the pressure ring body (3) and the pressure ring surface (6) and is secured by screws.

4. The drawing die structure according to claim 1, characterized in that, The pressure ring body (3) is provided with a balance top rod at each of the four corners around its perimeter; the pressure ring body (3) is also provided with a positioning groove at each of the four corners that is perpendicular to the part sheet, and a material support positioning device (19) is installed in the positioning groove.

5. The drawing die structure according to claim 1, characterized in that, The lower mold base (2) is provided with a plurality of positioning keys (10) on its top surface, and the bottom of the punch (4) has a keyway hole corresponding to the positioning keys (10); when the punch (4) is installed, the positioning keys (10) are embedded in the keyway hole.

6. The drawing die structure according to claim 1, characterized in that, The upper mold base (1) and the cavity mold (5) adopt a split structure; the upper mold base (1) has a recessed area in the middle of the bottom surface, and the upper mold base (1) is provided with upper fixing holes (24) spaced around the recessed area; the cavity mold (5) is placed in the recessed area and is fastened with reverse screws through the upper fixing holes (24).

7. The drawing die structure according to claim 6, characterized in that, The concave mold (5) and the upper mold base (1) are initially positioned by a backrest and a clamping key (22).

8. The drawing die structure according to claim 1, characterized in that, Safety bolts (25) are installed at the four corners of the recessed area of ​​the upper mold base (1), and the upper mold base (1) is connected to the concave mold (5) through the safety bolts (25).

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