Forming process of automobile connecting plate and automobile connecting plate

Abstract

The application relates to the technical field of automobile part manufacturing, and discloses a forming method of an automobile connecting plate and the automobile connecting plate. The automobile connecting plate comprises a bending part and a flange. The forming method of the automobile connecting plate comprises the following steps: S1, a pre-stretching process, a blank is stretched into a pre-stretching piece by using a pre-stretching die. The pre-stretching piece comprises a pre-stretching bending part and a pre-stretching flange; S2, a secondary stretching process, the pre-stretching piece is stretched into a secondary stretching piece by using a secondary stretching die. The secondary stretching piece comprises a secondary stretching bending part and a secondary stretching flange; and S3, edge cutting, the secondary stretching end pressing area in the secondary stretching piece is cut off. The forming method of the automobile connecting plate and the automobile connecting plate can improve the forming process flow of the automobile connecting plate, solve the round corner cracking problem of the connecting plate, and reduce the rebound and wrinkle conditions of the connecting plate.

Description

Technical Field

[0001] This invention relates to the field of automotive parts manufacturing technology, and in particular to a molding process for an automotive connecting plate and the automotive connecting plate itself. Background Technology

[0002] Currently, vehicle body strength refers to the body's ability to withstand significant external forces, such as collisions, without easily being damaged. Insufficient strength will affect the vehicle's safety performance. Therefore, connecting plates are installed between body assemblies to improve body strength. These connecting plates are mostly made of high-strength steel 340 / 590DP. While 340 / 590DP is high-strength steel, its formability is relatively poor. Connecting plates made from this material are prone to springback during the forming process, cracking around the rounded corners, and wrinkling in the connecting sections.

[0003] In the existing technology, the above-mentioned problems cannot be well eliminated in the preparation of the connecting plate. Summary of the Invention

[0004] The purpose of this invention is to provide a molding method for automotive connecting plates to improve the molding process of automotive connecting plates, solve the problem of corner cracking of connecting plates, and reduce the springback and wrinkling of connecting plates.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for forming an automotive connecting plate, the automotive connecting plate comprising a bent portion and flanges, the bent portion comprising a top plate and side plates respectively connected to both sides of the top plate, the top plate and the side plates being connected by a stretch fillet, the central angle of the stretch fillet being α, the bent portion being concave when viewed from the side, and the flanges being respectively disposed along the bottom edge of the side plates, comprising the following steps:

[0007] S1. Pre-stretching process: A pre-stretching die is used to stretch a blank into a pre-stretched part. The pre-stretched part includes a pre-stretching bending section and pre-stretching flanges. The pre-stretching bending section includes a pre-stretching top plate and pre-stretching side plates connected to both sides of the pre-stretching top plate. The pre-stretching top plate and the pre-stretching side plates are connected by a transition fillet. The central angle of the transition fillet is α1, and α1 < α. When viewed from the side, the pre-stretching bending section is concave. The pre-stretching flanges are respectively set along the bottom edge of the pre-stretching side plates. The pre-stretching flanges include a pre-stretching end pressure area and a pre-stretching side pressure area connected sequentially from front to back. The pre-stretching die includes a pre-stretching die, which includes a first working surface and a second working surface connected sequentially from front to back. The first working surface and the second working surface have a smooth transition. The pre-stretching die also includes a pre-stretching portion, which is located in the middle of the second working surface, and the front end of the pre-stretching portion extends forward to the first working surface. A pre-stretching bending portion is formed on the pre-stretching portion, a pre-stretching end pressure area is formed on the first working surface, and a pre-stretching side pressure area is formed on the second working surface. After the pre-stretching process is completed, at least part of the front edge of the pre-stretched part does not extend to the first working surface.

[0008] S2. Secondary stretching process: A secondary stretching die is used to stretch the pre-stretched part into a secondary stretched part. The secondary stretched part includes a secondary stretching bend and secondary stretching flanges. The secondary stretching bend includes a secondary stretching top plate and secondary stretching side plates connected to both sides of the secondary stretching top plate. The secondary stretching top plate and the secondary stretching side plates form a stretching fillet. Viewed from the side, the secondary stretching bend is concave. The secondary stretching flanges are respectively provided along the bottom edge of the secondary stretching side plates. The pre-stretched flange includes a secondary stretching end pressure area and a secondary stretching side pressure area connected sequentially from front to back. The secondary stretching die includes a secondary stretching die, which includes... The third and fourth working surfaces are connected sequentially from front to back, with a smooth transition between them. The secondary stretching die also includes a secondary stretching section located in the middle of the fourth working surface, with its front end extending forward onto the third working surface. The secondary stretching bending section is formed on the secondary stretching section, the secondary stretching end pressure area is formed on the third working surface, and the secondary stretching side pressure area is formed on the fourth working surface. After the secondary stretching process is completed, the pre-stretched bending section is formed into a secondary stretching bending section through secondary stretching. The secondary stretching bending section is the bending section of the automotive connecting plate, and the pre-stretched flange is formed into the secondary stretching flange.

[0009] S3. Trim the edge: Cut off the secondary stretching end pressure area in the secondary stretching member.

[0010] Further, in step S1, when viewed along any cross-section of the pre-stretched member, the height of the pre-stretched bending portion is h1, and when viewed along any cross-section of the secondary stretching member, the height of the secondary stretching bending portion is h2, where h1 < h2.

[0011] Furthermore, h2 = 15 to 20h1.

[0012] Furthermore, in step S1, α1 = 0.5 to 0.75α.

[0013] Further, in step S1, the first working surface is a plane, and the angle between the tangent direction of the second working surface at the position where it connects to the first working surface and the first working surface is 120° to 160°; the third working surface is a plane, and the angle between the tangent direction of the fourth working surface at the position where it connects to the third working surface and the fourth working surface is 120° to 160°.

[0014] Further, in step S1, the blank includes a body and end corners, and the pre-stretch end pressing zone is formed in the pre-stretch mold through the end corners.

[0015] Furthermore, in step S1, a pre-stretching die fillet is connected between the first working surface and the second working surface; a secondary stretching die fillet is connected between the third working surface and the fourth working surface.

[0016] Furthermore, the radii corresponding to the fillets of the pre-stretching mold and the secondary stretching mold are both greater than 10cm.

[0017] Furthermore, after the secondary stretching process is completed, the extension length of the secondary stretching end pressure zone along the front-to-back direction is 8 to 15 cm.

[0018] Secondly, the present invention provides an automotive connecting plate, which is prepared by the molding method of the automotive connecting plate in the first aspect.

[0019] The present invention discloses a method for forming an automotive connecting plate, and the automotive connecting plate, compared with the prior art, has the following advantages: Firstly, the automotive connecting plate is pre-formed through a pre-stretching process to harden the transition fillets, and then the fillets are stretched through a secondary stretching process, reducing the springback problem of the automotive connecting plate; Two working surfaces are respectively set in the pre-stretching and secondary stretching molds, with a large included angle at the junction of the two working surfaces, and the double working surface contact reduces wrinkling during the stretching process; During pre-stretching, the pre-stretching flange covers the fillet of the first mold, and the middle of the pre-stretched part does not completely cover the fillet of the first mold, facilitating the flow of excess material along the two end-pressure zones, solving the problem of thinning in the end-pressure zones, and thus improving the cracking and wrinkling problems in the end-pressure zones. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the pre-stretched part and the pre-stretched die according to an embodiment of the present invention;

[0021] Figure 2 yes Figure 1 Schematic diagram of AA section;

[0022] Figure 3 This is a schematic diagram of the structure of the secondary stretching component according to an embodiment of the present invention;

[0023] Figure 4 This is an overall schematic diagram of the automotive connecting plate according to an embodiment of the present invention;

[0024] In the picture,

[0025] 1. Automotive connecting plate; 11. Bending section; 111. Roof plate; 112. Side plate; 113. Stretch fillet; 12. Flange;

[0026] 2. Pre-stretched part; 21. Pre-stretched bending section; 211. Pre-stretched top plate; 212. Pre-stretched side plate; 213. Transition fillet; 22. Pre-stretched flange; 221. Pre-stretched end pressure area; 222. Pre-stretched side pressure area; 3. Pre-stretched die; 31. First working surface; 32. Second working surface; 33. Pre-stretched section; 34. Pre-stretched die fillet;

[0027] 4. Secondary stretching component; 41. Secondary stretching bending section; 411. Secondary stretching top plate; 412. Secondary stretching side plate; 42. Secondary stretching flange. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0029] In the description of this invention, the terms "upper," "lower," "left," "right," "front," "rear," "inner," "outer," "lateral," and "longitudinal," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation, and therefore should not be construed as limiting this utility model. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0030] In the description of this invention, the terms "provided with," "set up," "connected," and "placed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0032] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings.

[0033] A preferred embodiment of the present invention provides a method for forming an automotive connecting plate 1. The automotive connecting plate 1 includes a bent portion 11 and flanges 12. The bent portion 11 includes a top plate 111 and side plates 112 respectively connected to both sides of the top plate 111. The top plate 111 and the side plates 112 are connected by a stretch fillet 113, the central angle of which is α. Viewed from the side, the bent portion 11 is concave. The flanges 12 are respectively provided along the bottom edge of the side plates 112. The method includes the following steps:

[0034] S1. Pre-stretching process: The blank is stretched into a pre-stretched part 2 using a pre-stretching die. The pre-stretched part 2 includes a pre-stretched bending section 21 and pre-stretched flanges 22. The pre-stretched bending section 21 includes a pre-stretched top plate 211 and pre-stretched side plates 212 connected to both sides of the pre-stretched top plate 211. The pre-stretched top plate 211 and the pre-stretched side plates 212 are connected by a transition fillet 213. The central angle of the transition fillet 213 is α1, and α1 < α. When viewed from the side, the pre-stretched bending section 21 is concave. The pre-stretched flanges 22 are respectively set along the bottom edge of the pre-stretched side plates 212. The pre-stretched flanges 22 include a pre-stretched end pressure area 221 connected sequentially from front to back and... The pre-stretch side pressure area 222; the pre-stretch die includes a pre-stretch die 3, which includes a first working surface 31 and a second working surface 32 connected sequentially from front to back. The first working surface 31 and the second working surface 32 have a smooth transition. The pre-stretch die 3 also includes a pre-stretch portion 33, which is located in the middle of the second working surface 32, and the front end of the pre-stretch portion 33 extends forward to the first working surface 31; the pre-stretch bending portion 21 is formed on the pre-stretch portion 33, the pre-stretch end pressure area 221 is formed on the first working surface 31, and the pre-stretch side pressure area 222 is formed on the second working surface 32; after the pre-stretching process is completed, at least part of the front edge of the pre-stretched part 2 does not extend to the first working surface 31.

[0035] S2. Secondary stretching process: The pre-stretched part 2 is stretched into a secondary stretched part 4 using a secondary stretching die. The secondary stretched part 4 includes a secondary stretching bending section 41 and secondary stretching flanges 42. The secondary stretching bending section 41 includes a secondary stretching top plate 411 and secondary stretching side plates 412 connected to both sides of the secondary stretching top plate 411. The secondary stretching top plate 411 and the secondary stretching side plates 412 are connected by a stretching fillet 113. Viewed from the side, the secondary stretching bending section 41 is concave. The secondary stretching flanges 42 are provided along the bottom edge of the secondary stretching side plates 412. The secondary stretching flanges 42 include a secondary stretching end pressure area and a secondary stretching side pressure area connected sequentially from front to back. Secondary stretching die The device includes a secondary stretching die, which includes a third working surface and a fourth working surface connected sequentially from front to back, with a smooth transition between the third and fourth working surfaces. The secondary stretching die also includes a secondary stretching section located in the middle of the fourth working surface, with its front end extending forward to the third working surface. A secondary stretching bending section 41 is formed on the secondary stretching section, a secondary stretching end pressure area is formed on the third working surface, and a secondary stretching side pressure area is formed on the fourth working surface. After the secondary stretching process is completed, the pre-stretched bending section 21 is formed into the secondary stretching bending section 41 through secondary stretching. The secondary stretching bending section 41 is the bending section 11 of the automotive connecting plate 1, and the pre-stretched flange 22 is formed into the secondary stretching flange 42.

[0036] S3. Trim the edge: Cut off the secondary stretching end pressure area in the secondary stretching part 4.

[0037] Based on the above technical solution, the process flow of the molding method for automotive connecting plates is as follows:

[0038] The blank is placed in the pre-stretching mold to form a pre-stretched part. The pre-stretching part 33 of the pre-stretching mold forms the pre-stretching bending part 21, the first working surface 31 forms the pre-stretching end pressure area 221, and the second working surface 32 forms the pre-stretching side pressure area 222.

[0039] The pre-stretched part 2 is placed in the secondary stretching mold. The pre-stretched bending part 21 is positioned in conjunction with the secondary stretching part. The secondary stretching part shapes the pre-stretched bending part 21 into the secondary stretching bending part 41. The third working surface forms the second stretching end pressure area, and the fourth working surface forms the second stretching side pressure area.

[0040] After the stretching process is completed, the remaining material of the secondary stretched part is trimmed to obtain the automotive connecting plate 1.

[0041] Preferably, in step S1, when viewed along any cross-section of the pre-stretched member 2, the height of the pre-stretched bent portion 21 is h1, and when viewed along any cross-section of the secondary stretched member 4, the height of the secondary stretched bent portion 41 is h2, where h1 < h2. The height of the secondary stretched side plate 412 is set greater than the height of the pre-stretched side plate 212 to form the bent portion 11 of the automotive connecting plate 1, and the fitting depth of the groove in the bent portion 11 conforms to the height of the automotive connecting beam.

[0042] More preferably, h2 = 15-20h1, and more preferably h2 = 16h1. The height of the secondary stretching side plate 412 is set to 15-20 times the height of the pre-stretching side plate 212 to prevent damage or breakage from excessive secondary stretching forming height.

[0043] Preferably, in step S1, α1 = 0.5 to 0.75α, and more preferably α is 0.66α. The transition fillet 213 formed by the pre-stretching process is set to 0.5 to 0.75 times the stretching fillet 113 of the automotive connecting plate 1. First, the stretching fillet 113 is partially formed by the pre-stretching process to harden the fillet, reduce the springback of the secondary stretching, and at the same time ensure that the pre-stretched part is stably positioned in the secondary stretching mold.

[0044] Preferably, in step S1, the first working surface 31 is a plane, and the angle between the tangent direction of the second working surface 32 at the position where it connects to the first working surface 31 and the first working surface 31 is 120° to 160°, preferably 140°; the third working surface is a plane, and the angle between the tangent direction of the fourth working surface at the position where it connects to the third working surface and the fourth working surface is 120° to 160°, preferably 140°. The angle between the connection point of the first working surface 31 and the second working surface 32 is set to 120° to 160°, and the angle between the connection point of the third working surface and the fourth working surface is set to 120° to 160°. During the pre-stretching and secondary stretching steps, the pre-stretched part and the secondary stretched part 4 come into contact with each other in two directions, reducing wrinkling during the molding process.

[0045] Preferably, in step S1, the blank includes a body and end corners, and the pre-stretch end-pressing zone 221 is formed in the pre-stretching mold through the end corners. By reshaping the shape of the blank and increasing the end corners, it is ensured that the material elongation of the pre-stretch end-pressing zone 221 and the secondary stretching zone of the pre-stretched part 2 and the secondary stretching part 4 in the pre-stretching and secondary stretching processes is sufficient, preventing the end corners from becoming excessively thin and cracking.

[0046] Preferably, in step S1, a pre-stretching die fillet 34 connects the first working surface 31 and the second working surface 32; a secondary stretching die fillet connects the third working surface and the fourth working surface. Providing pre-stretching die fillets 34 and secondary stretching die fillets on the pre-stretching die and the secondary stretching die respectively prevents stress concentration points from forming on the corresponding parts at the connection points of the working surfaces, thus preventing damage to the parts.

[0047] More preferably, the radii corresponding to the pre-stretching die fillet 34 and the secondary stretching die fillet are both greater than 10cm. Setting the radii of the pre-stretching die fillet 34 and the secondary stretching die fillet to be greater than 10cm helps to reduce stress concentration at the connection points of the corresponding working surfaces of the parts.

[0048] Preferably, after the secondary stretching process is completed, the extension length of the secondary stretching end pressure zone in the front-to-back direction is 8-15 cm. The extension length of the secondary stretching end pressure zone in the front-to-back direction is determined based on the molding CAE analysis. When the length is too long, the wrinkling condition of the part corresponding to the rounded corner of the second mold is improved, but the cracking of the secondary stretching end pressure zone is severe. When the length is too short, neither the wrinkling condition of the part corresponding to the rounded corner of the second mold nor the cracking of the second stretching end pressure zone can be improved.

[0049] Secondly, the present invention provides an automotive connecting plate 1, which is prepared by the molding method of the automotive connecting plate 1 in the first aspect.

[0050] The working process of this invention is as follows: A blank with end corners is formed through a blanking process. The blank is placed in a pre-stretching mold, with the end corners connected to the first working surface 31. The pre-stretching part 33 of the pre-stretching mold forms a pre-stretching bent part 21. The first working surface 31 forms a pre-stretching end pressure area 221, and the second working surface 32 forms a pre-stretching side pressure area 222. The pre-stretched part 2 is placed in a secondary stretching mold. The pre-stretching bent part 21 is positioned in conjunction with the secondary stretching part. The secondary stretching part forms the pre-stretching bent part 21 into a secondary stretching bent part 41. The third working surface forms a second stretching end pressure area, and the fourth working surface forms a second stretching side pressure area. After the stretching process is completed, the remaining material of the secondary stretching part is trimmed to obtain the automotive connecting plate 1.

[0051] In summary, the embodiments of the present invention provide a forming method for an automotive connecting plate and an automotive connecting plate. The method involves pre-forming the automotive connecting plate using a pre-stretching process to harden the transition fillets, followed by a secondary stretching process to stretch the fillets, thus mitigating the springback problem of the automotive connecting plate. Two working surfaces are respectively provided in the pre-stretching and secondary stretching molds, with a large included angle at the junction of the two working surfaces. The double working surface contact reduces wrinkling during the stretching process. During pre-stretching, the pre-stretching flange covers the fillet of the first mold, while the middle of the pre-stretched part does not completely cover the fillet of the first mold, facilitating the flow of excess material along the two end-pressure zones, solving the problem of thinning in the end-pressure zones, and thus improving the cracking and wrinkling problems in the end-pressure zones.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A method for forming an automotive connecting plate, used to prepare an automotive connecting plate, the automotive connecting plate including a bent portion and flanges, the bent portion including a top plate and side plates respectively connected to both sides of the top plate, the top plate and the side plates being connected by a stretch fillet, the central angle of the stretch fillet being α, the bent portion being concave when viewed from the side, and the flanges being respectively provided along the bottom edge of the side plates, characterized in that... Includes the following steps: S1. Pre-stretching process: A pre-stretching die is used to stretch a blank into a pre-stretched part. The pre-stretched part includes a pre-stretching bending section and pre-stretching flanges. The pre-stretching bending section includes a pre-stretching top plate and pre-stretching side plates connected to both sides of the pre-stretching top plate. The pre-stretching top plate and the pre-stretching side plates are connected by a transition fillet. The central angle of the transition fillet is α1, and α1 < α. When viewed from the side, the pre-stretching bending section is concave. The pre-stretching flanges are respectively set along the bottom edge of the pre-stretching side plates. The pre-stretching flanges include a pre-stretching end pressure area and a pre-stretching side pressure area connected sequentially from front to back. The pre-stretching die includes a pre-stretching die, which includes a first working surface and a second working surface connected sequentially from front to back. The first working surface and the second working surface have a smooth transition. The pre-stretching die also includes a pre-stretching portion, which is located in the middle of the second working surface, and the front end of the pre-stretching portion extends forward to the first working surface. A pre-stretching bending portion is formed on the pre-stretching portion, a pre-stretching end pressure area is formed on the first working surface, and a pre-stretching side pressure area is formed on the second working surface. After the pre-stretching process is completed, at least part of the front edge of the pre-stretched part does not extend to the first working surface. S2. Secondary stretching process: A secondary stretching die is used to stretch the pre-stretched part into a secondary stretched part. The secondary stretched part includes a secondary stretching bend and secondary stretching flanges. The secondary stretching bend includes a secondary stretching top plate and secondary stretching side plates connected to both sides of the secondary stretching top plate. The secondary stretching top plate and the secondary stretching side plates form a stretching fillet. Viewed from the side, the secondary stretching bend is concave. The secondary stretching flanges are respectively provided along the bottom edge of the secondary stretching side plates. The secondary stretching flanges include a secondary stretching end pressure area and a secondary stretching side pressure area connected sequentially from front to back. The secondary stretching die includes a secondary stretching die, which includes... The third and fourth working surfaces are connected sequentially from front to back, with a smooth transition between them. The secondary stretching die also includes a secondary stretching section located in the middle of the fourth working surface, with its front end extending forward onto the third working surface. The secondary stretching bending section is formed on the secondary stretching section, the secondary stretching end pressure area is formed on the third working surface, and the secondary stretching side pressure area is formed on the fourth working surface. After the secondary stretching process is completed, the pre-stretched bending section is formed into a secondary stretching bending section through secondary stretching. The secondary stretching bending section is the bending section of the automotive connecting plate, and the pre-stretched flange is formed into the secondary stretching flange. S3. Trim the edge: Cut off the secondary stretching end pressure area in the secondary stretching member.

2. The method for forming an automotive connecting plate according to claim 1, characterized in that: In step S1, when viewed along any cross-section of the pre-stretched member, the height of the pre-stretched bending portion is h1, and when viewed along any cross-section of the secondary stretching member, the height of the secondary stretching bending portion is h2, where h1 < h2.

3. The method for forming an automotive connecting plate according to claim 2, characterized in that: h2 = 15 ~ 20h1.

4. The method for forming an automotive connecting plate according to claim 1, characterized in that: In step S1, α1 = 0.5 to 0.75α.

5. The method for forming an automotive connecting plate according to claim 1, characterized in that: In step S1, the first working surface is a plane, and the angle between the tangent direction of the second working surface at the position where it connects to the first working surface and the first working surface is 120° to 160°; the third working surface is a plane, and the angle between the tangent direction of the fourth working surface at the position where it connects to the third working surface and the fourth working surface is 120° to 160°.

6. The method for forming an automotive connecting plate according to claim 1, characterized in that: In step S1, the blank includes a body and end corners, and the pre-stretched end pressing zone is formed in the pre-stretching mold through the end corners.

7. The method for forming an automotive connecting plate according to claim 1, characterized in that: In step S1, a pre-stretching die fillet is connected between the first working surface and the second working surface; a secondary stretching die fillet is connected between the third working surface and the fourth working surface.

8. The method for forming an automotive connecting plate according to claim 7, characterized in that: The radii corresponding to the fillets of the pre-stretching mold and the secondary stretching mold are both greater than 10cm.

9. The method for forming an automotive connecting plate according to claim 7, characterized in that: After the secondary stretching process is completed, the extension length of the secondary stretching end pressure zone along the front-to-back direction is 8 to 15 cm.

10. An automotive connecting plate, characterized in that: It is prepared by the molding method of the automotive connecting plate as described in any one of claims 1-9.

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