Forming process and forming die for the outlet end cone of an automotive exhaust system

Abstract

The present invention discloses a forming process and a forming die for the outlet end cone of an automobile exhaust system. The process includes processing steps such as blanking, forming the profile, pre-punching the small-diameter end, trimming, flanging the large-diameter end, punching and forming the small-diameter end, and flanging the small-diameter end. The outlet end cone shell is formed by high-quality stamping, which can effectively avoid phenomena such as wrinkles and cracks on the outer wall of the shell. The transitions at various places are uniform, and the qualified rate of the finished product is high.

Description

Technical Field

[0001] The present invention belongs to the field of stamping forming, and particularly relates to a forming process and a forming die for the outlet end cone of an automobile exhaust system. Background Art

[0002] As shown in the Figure 1 figure, an outlet end cone housing 100 of an automobile exhaust system has a variable-diameter bent tube structure and is made of stainless steel. It includes a large-diameter end 101 and a small-diameter end 102, and the large-diameter end 101 and the small-diameter end 102 respectively include a large-diameter flanging 103 and a small-diameter flanging 104. Both the large-diameter flanging 103 and the small-diameter flanging 104 are regular circular ring structures, and there is a convex structure 105 protruding outward on the outer bent wall of the outlet end cone. Since the distance between the large-diameter end 101 and the small-diameter end 102 is small, it is not easy to process. Summary of the Invention

[0003] Object of the Invention: In order to overcome the deficiencies in the prior art, the present invention provides a forming process and a forming die for the outlet end cone of an automobile exhaust system to stamp and form the outlet end cone housing with high quality.

[0004] Technical Solution: To achieve the above object, the technical solution of the present invention is as follows:

[0005] A forming process for the outlet end cone of an automobile exhaust system includes the following steps:

[0006] S1: Blanking: Using a straight double-row layout method, the blanking sheet has a circular sheet structure, and there are two coplanar lugs on the circular contour, and the two lugs are symmetrically distributed;

[0007] S2: Forming the profile: Form the inner cavity and outer profile of the outlet end cone housing through a stamping die, and the sheet metal corresponding to the small-diameter end is not drawn and ruptured;

[0008] S3: Pre-punching the small-diameter end: Pre-punch the sheet metal corresponding to the small-diameter end in step S2 through a punching die, and the diameter of the pre-punched hole is smaller than the port size of the small-diameter end;

[0009] S4: Trimming: Cut off the surplus material of the outer contour of the large-diameter end in step S3;

[0010] S5: Flanging the large-diameter end: Flange the large-diameter end through a flanging die to form a regular circular port;

[0011] S6: Punching and forming the small-diameter end: Punch and process the small-diameter end through a punching die;

[0012] S7: Flanging the small-diameter end: Expand and flange the small-diameter end outward to form a regular circular port;

[0013] S8: Bulging: Processing and forming the convex structure.

[0014] A combined mold for forming an air outlet end cone, including an upper template and a lower template that open and close with each other, and a punching and forming module, a hole flanging and forming module, and a bulging and forming module are sequentially arranged adjacent to each other between the upper template and the lower template. The punching and forming module, the hole flanging and forming module, and the bulging and forming module respectively perform small-diameter end punching and forming processing, small-diameter end hole flanging and forming, and bulging and forming of the convex structure on the semi-finished product of the air outlet end cone shell.

[0015] Further, the punching and forming module includes a first pressure plate, a first punching punch, a first punching die, and a first die insert. The first punching die is arranged on the lower template, and the first die insert is detachably arranged on the first punching die. The first die insert includes a first positioning surface A, and the first positioning surface A is adapted to the inner contour surface of the air outlet end cone. A punching opening is formed through the first die insert, and the punching opening has a regular circular structure, and the axial direction of the punching opening is vertically downward; the first pressure plate is elastically telescopically arranged on the upper template, and the bottom surface of the first pressure plate includes a first positioning surface B adapted to the outer contour surface of the air outlet end cone shell. The first punching punch is arranged on the upper template, and the first punching punch passes through the first pressure plate corresponding to the punching opening.

[0016] Further, the hole flanging and forming module includes a second pressure plate, a second forming die, and a second hole flanging and forming punch. The second pressure plate is elastically telescopically arranged on the lower template. A second hole flanging and forming punch is arranged on the lower template, and the second hole flanging and forming punch extends upward through the second pressure plate. The second forming die is fixedly arranged on the bottom surface of the upper template, and the bottom surface of the second forming die is recessed with a second positioning surface A adapted to the outer contour of the air outlet end cone. A hole flanging and forming die corresponding to the second hole flanging and forming punch is formed through the second forming die; in the closed mold state, the second hole flanging and forming punch extends into the hole flanging and forming die to expand and flange the small-diameter end port of the hole.

[0017] Further, the second hole flanging and forming punch includes a second positioning part and a hole flanging part integrally arranged. The second positioning part is connected to the second pressure plate, and the second positioning part includes a second positioning surface B adapted to the inner contour surface of the air outlet end cone. The hole flanging part is a cylindrical rod structure, and the axis of the hole flanging part is vertically arranged.

[0018] Further, it further includes a second upper top plate. The second upper top plate is arranged in the hole flanging and forming die with a gap, and the bottom end of the second upper top plate includes an annular upper top ring, and the inner diameter of the upper top ring is smaller than the diameter of the hole flanging part; in the closed mold state, the upper top ring presses against the small-diameter end port of the air outlet end cone.

[0019] Furthermore, the convex forming module includes a third pressure plate, a convex punching rod, and a third convex die and concave die. The third pressure plate is elastically telescopic and arranged on the lower template. The third pressure plate is provided with a third positioning profile adapted to the inner contour of the air outlet end cone. The third pressure plate is vertically provided with a guiding through hole. The bottom end of the convex punching rod is fixedly arranged on the lower template, and the other end of the convex punching rod vertically penetrates through the guiding through hole. The third convex die and concave die is arranged on the upper template corresponding to the third pressure plate, and a forming groove corresponding to the convex punching rod is recessed on the third convex die and concave die.

[0020] Beneficial effects: The process steps of the present invention can stamping and forming process the air outlet end cone shell with high quality, and can effectively avoid phenomena such as wrinkles and cracks on the outer wall of the shell. The transitions and turns at various places are uniform, and the qualified rate of the finished product is high. Description of the Drawings

[0021] Attached Figure 1 is a schematic structural diagram of the air outlet end cone shell processed by the present invention;

[0022] Attached Figure 2 is a layout schematic diagram in process step S1 of the present invention;

[0023] Attached Figure 3 is a schematic diagram of the forming profile in process step S2 of the present invention;

[0024] Attached Figure 4 is a schematic diagram of the pre-punching of the small-diameter end in process step S3 of the present invention;

[0025] Attached Figure 5 is a trimming schematic diagram in process step S4 of the present invention;

[0026] Attached Figure 6 is a flanging schematic diagram of the large-diameter end in process step S5 of the present invention;

[0027] Attached Figure 7 is a punching and forming schematic diagram of the small-diameter end in process step S6 of the present invention;

[0028] Attached Figure 8 is a hole flanging schematic diagram of the small-diameter end in process step S7 of the present invention;

[0029] Attached Figure 9 is a convex forming schematic diagram in process step S8 of the present invention;

[0030] Attached Figure 10 is a front view of the overall structure of the combined die of the present invention;

[0031] Attached Figure 11 is a top view of the lower template of the combined die of the present invention;

[0032] Attached Figure 12 Perspective view of the upper template of the combined mold of the present invention. Detailed implementation manners

[0033] The present invention will be further described below with reference to the accompanying drawings.

[0034] As shown in the attached Figure 2 to the attached Figure 9 A forming process for the outlet end cone of an automotive exhaust system includes the following steps:

[0035] S1: Blanking: Using a straight double-row nesting method, the blanking piece has a circular sheet structure and includes two coplanar lug ears on the circular contour, and the two lug ears are symmetrically distributed; the function of the lug ears is to ensure rapid positioning of the blanking piece when forming the profile.

[0036] S2: Forming the profile: Forming the inner cavity and outer profile of the outlet end cone housing through a stamping die to form a convex structure, and the sheet metal corresponding to the small-diameter end is not drawn and ruptured.

[0037] S3: Pre-punching the small-diameter end: Pre-punching the sheet metal corresponding to the small-diameter end in step S2 through a punching die, and the diameter of the pre-punched hole is smaller than the port size of the small-diameter end.

[0038] S4: Trimming: Removing the excess material of the outer contour of the large-diameter end in step S3.

[0039] S5: Flanging the large-diameter end: Flanging the large-diameter end through a flanging die to form a regular circular port.

[0040] S6: Punching and forming the small-diameter end: Punching and forming the small-diameter end through a punching die.

[0041] S7: Flanging the small-diameter end: Flanging and expanding the small-diameter end outward to form a regular circular port.

[0042] S8: Boss forming: Machining and forming the boss structure.

[0043] As shown in the attached Figure 10 to the attached Figure 12 A combined mold for forming the outlet end cone of an automotive exhaust system includes an upper template 1 and a lower template 2 that open and close with each other, and a punching and forming module, a flanging and forming module, and a boss forming module are sequentially arranged adjacent to each other between the upper template 1 and the lower template 2. The punching and forming module, the flanging and forming module, and the boss forming module respectively perform punching and forming processing on the small-diameter end, flanging and forming on the small-diameter end, and boss forming on the raised structure of the semi-finished product of the outlet end cone housing. Through the co-mold setting of the three modules, different forming processes can be simultaneously performed on multiple outlet end cone housings 100 during one opening and closing process of the mold, which can greatly improve the processing efficiency and reduce the manufacturing cost of the mold.

[0044] The punching and forming module includes a first pressure plate 11, a first punching punch 11, a first punching die 18 and a first die insert 16. The first punching die 18 is arranged on the lower template 2, and the first die insert 16 is detachably arranged on the first punching die 18. The first die insert 16 includes a first positioning surface A13, and the first positioning surface A13 is adapted to the inner contour surface of the air outlet end cone. A punching opening 19 is formed through the first die insert 16. The punching opening 19 has a regular circular structure, and the axis of the punching opening 19 is vertically downward; the first pressure plate 11 is elastically telescopically arranged on the upper template 1 and is guided by a guide block 17. The bottom surface of the first pressure plate 11 includes a first positioning surface B adapted to the outer contour surface of the air outlet end cone housing. The first punching punch 11 is arranged on the upper template, and the first punching punch 11 passes through the first pressure plate corresponding to the punching opening 19. When the mold is closed, the first punching punch 11 moves up and down to punch the small-diameter end 102 of the air outlet end cone housing to ensure that the cut edge of the small-diameter end port is flat.

[0045] The hole flanging and forming module includes a second pressure plate 20, a second forming die 22 and a second hole flanging and forming punch 23. The second pressure plate 20 is elastically telescopically arranged on the lower template 2. The second hole flanging and forming punch 23 is arranged on the lower template 2 and extends upward through the second pressure plate 20. The second forming die 22 is fixedly arranged on the bottom surface of the upper template 1, and the bottom surface of the second forming die 22 is recessed with a second positioning surface A25 adapted to the outer contour of the air outlet end cone housing 100. A hole flanging and forming die 26 corresponding to the second hole flanging and forming punch 25 is formed through the second forming die 22; in the closed mold state, the second hole flanging and forming punch 23 extends into the hole flanging and forming die 26 to expand and flange the small-diameter end port. By arranging the second pressure plate 20 on the lower template and the second hole flanging and forming die 22 on the upper template, in the open mold state, the second pressure plate 20 rebounds upward to position and support the air outlet end cone housing 100 through the second pressure plate 20, and when the mold is closed, the small-diameter end of the air outlet end cone housing is expanded and flanged by the second hole flanging and forming punch 23.

[0046] Wherein, the second hole flanging and forming punch 23 includes a second positioning part and a hole flanging part integrally arranged. The second positioning part is connected to the second pressure plate 20, and the second positioning part includes a second positioning surface B24 adapted to the inner contour surface of the air outlet end cone. The hole flanging part is a cylindrical rod structure, and the axis of the hole flanging part is vertically arranged.

[0047] It further includes a second upper top plate 21 which is arranged in the flanging forming female die 22 with a gap, and the bottom end of the second upper top plate 21 includes an annular upper top ring 27, the inner diameter of the upper top ring 27 being smaller than the diameter of the flanging part; in the mold closing state, the upper top ring 27 presses against the small-diameter end port of the air outlet end conical shell 100 to ensure the flatness of the small-diameter end port, and enables the sheet material at the small end port to be extruded and formed between the flanging forming female die 22 and the flanging part.

[0048] The convex forming module includes a third pressure plate 33, a convex punching rod 32 and a third convex forming female die 31. The third pressure plate 33 is elastically telescopic and arranged on the lower template 2. The third pressure plate is provided with a third positioning surface adapted to the inner contour of the air outlet end cone. The third pressure plate 33 is provided with a guiding through hole 34 penetrating in the vertical direction. The bottom end of the convex punching rod 32 is fixedly arranged on the lower template 2, and the other end of the convex punching rod 32 vertically penetrates through the guiding through hole 34. The third convex forming female die 31 is arranged on the upper template corresponding to the third pressure plate 31, and a forming groove 35 corresponding to the convex punching rod 32 is recessed on the third convex forming female die 31. The convex punching rod 32 is vertically arranged and perpendicular to the outwardly bent plate body. When the mold is closed, the convex structure 105 is processed and formed by the convex punching rod 32.

[0049] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A forming process for the outlet end cone of an automotive exhaust system, characterized in that: It includes the following steps: S1: Blanking: In a straight double-row nesting method, the blanking piece is in a circular sheet structure and has two coplanar lug ears on the circular contour, and the two lug ears are symmetrically distributed; S2: Forming the profile: The inner cavity and outer profile of the outlet end cone shell are formed by a stamping die, and the sheet metal corresponding to the small-diameter end is not drawn and cracked; S3: Pre-punching the small-diameter end: The sheet metal corresponding to the small-diameter end in step S2 is pre-punched through a punching die, and the diameter of the pre-punched hole is smaller than the port size of the small-diameter end; S4: Trimming: The surplus material of the outer contour of the large-diameter end in step S3 is removed; S5: Flanging the large-diameter end: The large-diameter end is flanged through a flanging die to form a regular circular port; S6: Punching and forming the small-diameter end: The small-diameter end is processed and formed by punching through a punching die; S7: Flanging the small-diameter end: The small-diameter end is expanded and flanged outward to form a regular circular port; S8: Boss forming: The boss structure is processed and formed.

2. A combined die for implementing the forming process of the outlet end cone described in claim 1, characterized in that: It includes an upper template (1) and a lower template (2) that open and close with each other, and a punching and forming module, a flanging and forming module, and a boss forming module are sequentially arranged adjacent to each other between the upper template (1) and the lower template (2). The punching and forming module, the flanging and forming module, and the boss forming module respectively perform small-diameter end punching and forming processing, small-diameter end flanging and forming, and boss forming of the outlet end cone shell semi-finished product; The boss forming module includes a third pressure plate (33), a boss punching rod (32), and a third boss punching die (31). The third pressure plate (33) is elastically telescoped on the lower template (2). The third pressure plate has a third positioning profile adapted to the inner contour of the outlet end cone. The third pressure plate (33) is provided with a guiding through hole (34) penetrating in the vertical direction. The bottom end of the boss punching rod (32) is fixedly arranged on the lower template (2), and the other end of the boss punching rod (32) vertically penetrates through the guiding through hole (34). The third boss punching die (31) is arranged on the upper template corresponding to the third pressure plate, and a forming groove (35) corresponding to the boss punching rod (32) is recessed on the third boss punching die (31).

3. A combined die for implementing the forming process of the outlet end cone according to claim 2, characterized in that: The punching and forming module includes a first pressure plate, a first punching punch (11), a first punching die (18), and a first die insert (16). The first punching die (18) is disposed on the lower template (2), and the first die insert (16) is detachably disposed on the first punching die (18). The first die insert (16) includes a first positioning surface A (13), and the first positioning surface A (13) is adapted to the inner contour surface of the air outlet end cone. A punching opening (19) is formed through the first die insert (16). The punching opening (19) has a regular circular structure, and the axis of the punching opening (19) is vertically downward. The first pressure plate is elastically telescopically disposed on the upper template (1). The bottom surface of the first pressure plate includes a first positioning surface B adapted to the outer contour surface of the air outlet end cone housing. The first punching punch (11) is disposed on the upper template, and the first punching punch (11) passes through the first pressure plate corresponding to the punching opening (19).

4. The combined die for implementing the forming process of the air outlet end cone according to claim 2, characterized in that: The hole flanging and forming module includes a second pressure plate (20), a second forming die (22), and a second hole flanging and forming punch (23). The second pressure plate (20) is elastically telescopically disposed on the lower template (2). The second hole flanging and forming punch (23) is disposed on the lower template (2), and the second hole flanging and forming punch (23) extends upward through the second pressure plate (20). The second forming die (22) is fixedly disposed on the bottom surface of the upper template (1), and the bottom surface of the second forming die (22) is recessed with a second positioning surface A (25) adapted to the outer contour of the air outlet end cone housing (100). A hole flanging and forming die (26) corresponding to the second hole flanging and forming punch is formed through the second forming die (22). In the closed die state, the second hole flanging and forming punch (23) extends into the hole flanging and forming die (26) to expand the port of the small diameter end of the hole flanging.

5. The combined die for implementing the forming process of the air outlet end cone according to claim 4, characterized in that: The second hole flanging and forming punch (23) includes a second positioning portion and a hole flanging portion integrally provided. The second positioning portion is connected to the second pressure plate (20), and the second positioning portion includes a second positioning surface B (24) adapted to the inner contour surface of the air outlet end cone. The hole flanging portion has a cylindrical rod structure, and the axis of the hole flanging portion is vertically arranged.

6. The combined die for implementing the forming process of the air outlet end cone according to claim 5, characterized in that: It further includes a second upper top plate (21). The second upper top plate (21) is disposed in the hole flanging and forming die (22) with a gap. The bottom end of the second upper top plate (21) includes an annular upper top ring (27), and the inner diameter of the upper top ring (27) is smaller than the diameter of the hole flanging portion. In the closed die state, the upper top ring (27) presses against the port of the small diameter end of the air outlet end cone housing (100).

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