Three-way catalyst reducer shaping tool composite mold set

Abstract

The application discloses a three-way catalyst reducer shaping tool composite die set, which comprises a fixed die seat, the upper end face of which is provided with a lower die seat in parallel, two symmetrically arranged side die frames, which are symmetrically fixed on the fixed die seat and located on the two sides of the lower die seat, an upper stamping seat arranged above the fixed die seat, a first forming die set and a second forming die set, each of which is composed of two model plates arranged in an up-down mode, a die closing mechanism arranged below the lower die seat, and a plurality of reducer units, each of which is arranged at two reducer shaping ports of the first forming die set and the second forming die set. The double die set design of the application combines pre-reducing with accurate reducing, step-by-step forming is realized, size out-of-control caused by single large deformation is avoided, and a micro dynamic spinning shaping force is applied to the inside of the shell, so that the rebound is significantly reduced and the size stability after reducing is ensured.

Description

Technical Field

[0001] This invention belongs to the field of composite mold technology, specifically a composite mold assembly for three-way catalytic converter diameter reduction and shaping. Background Technology

[0002] The three-way catalytic converter is a core purification device in the automotive exhaust system. Its shell is typically made of metal (such as stainless steel) and encapsulated with a honeycomb ceramic carrier. Traditional external extrusion or stamping dies are prone to issues such as excessive ellipticity, axial bending, or uneven wall thickness reduction after diameter reduction. For example, in the utility model patent with publication number CN217798491U, the tooling cylinder is composed of multiple contoured long strips. During use, it relies solely on the external mold for forming, especially when the diameter reduction at both ends of the shell is large. With only external mold pressure and a lack of internal rigid support, the material shaping is uncontrollable, resulting in a large deviation between the actual inner diameter after diameter reduction and the design value. In addition, the metal shell is prone to elastic recovery after diameter reduction, and traditional static extrusion cannot effectively eliminate the rebound, causing the diameter reduction orifice to swell. This often requires secondary or multiple finishing processes, resulting in low production efficiency and high costs.

[0003] Therefore, it is necessary to provide a composite mold assembly for the three-way catalytic converter diameter reduction and shaping tooling to solve the problems mentioned in the background art. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a composite mold assembly for three-way catalytic converter diameter reduction and shaping, comprising: A fixed mold base is provided with a lower mold base parallel to its upper end face; The side mold frames are two symmetrically arranged, and the two side mold frames are symmetrically fixed on the fixed mold base and located on both sides of the lower mold base; The upper stamping base is horizontally set above the fixed mold base. Connecting frames are symmetrically fixed on both sides of the upper stamping base. Guide holes are opened through the connecting frames. Each side mold base is vertically fixed with a guide post. The upper end of the guide post is slidably connected to the guide hole. Both the first forming module and the second forming module are composed of two mold plates distributed vertically. The lower mold plate is embedded and fixed in the lower mold base, and the upper mold plate is embedded and fixed in the upper stamping base. The mold closing mechanism is located below the lower mold base; Multiple diameter reduction units are configured, and each diameter reduction unit is located at two diameter reduction shaping ports of the first forming module and the second forming module, respectively.

[0005] Furthermore, preferably, a propulsion device for driving the upper stamping seat to move downward is provided above the upper stamping seat; Furthermore, a transfer robotic arm is provided outside the fixed mold base. The transfer robotic arm is used to transport the pre-formed shell in the first molding module to the second molding module for precise diameter reduction and shaping.

[0006] Furthermore, preferably, the mold clamping mechanism includes: The spring support pillars are arranged vertically and symmetrically, and each spring support pillar is connected to the lower end face of the lower mold base. The lower end of the spring support pillar is slidably connected to the fixed mold base. Positioning pins are fixed at the four corners of the upper end face of the lower die base, and positioning holes corresponding to the positioning pins are opened in the upper stamping base; The template is horizontally set on the lower end face of the fixed template base, and the lower end of the spring support is connected to the template.

[0007] Furthermore, preferably, the diameter reduction unit includes: A support frame is horizontally slidably mounted on one side of a side mold frame, and two limiting plates are symmetrically fixed to the side mold frame by bolts; The hydraulic cylinder is horizontally fixed on the support frame; A diameter reduction device is installed at the telescopic end of the hydraulic cylinder; A fixed frame is fixed on the side mold frame and located below the support frame. Two guide rods are horizontally slidably connected to the fixed frame, and the other end of each guide rod is connected to the support frame. A cam is rotatably mounted within the fixed frame, and a transmission rod is hinged to the cam. The other end of the transmission rod is connected to the guide rod.

[0008] Furthermore, preferably, the diameter reduction device includes: A guide shaft, one end of which is coaxially connected to the telescopic end of the hydraulic cylinder; A bushing is coaxially sleeved on the end of the guide shaft away from the hydraulic cylinder. Multiple inward blocks are distributed around the circumference of the end of the bushing away from the hydraulic cylinder, and each inward block is hinged to the bushing. The inner mold core is fixed at the other end of the guide shaft.

[0009] Furthermore, as a preferred embodiment, a support spring is provided on the guide shaft and inside the bushing tube, and the support spring pushes the bushing tube away from the inner mold core in its natural state; Furthermore, a groove is provided inside the upper stamping seat, and the bushing tube is slidably positioned within the groove.

[0010] Furthermore, as a preferred embodiment, a guide tube is horizontally fixed on the side mold frame, and an outer section tube is horizontally rotatably connected to the support frame. One end of the outer section tube extends into and is connected to the guide tube, and the guide shaft is slidably connected to the outer section tube. A sliding groove is provided on the inner wall of the guide tube. The guide shaft is rotatably connected to the telescopic end of the hydraulic cylinder, and a guide pin is vertically fixed on the side wall of the outer section tube, and the guide pin is slidably connected to the slide groove.

[0011] Furthermore, as a preferred embodiment, the slide is configured with a wavy line structure, and each corner of the slide is provided with an arc-shaped guide groove, and the inner wall of the slide is provided with a backstop protrusion on the side near the corner.

[0012] Furthermore, as a preferred embodiment, each of the inner shrink blocks consists of two mutually hinged root diameter sections and inner wall sections, and a torsion spring is provided between the inner shrink block and the bushing.

[0013] Furthermore, preferably, a drive motor is installed below the fixing frame, and the output end of the drive motor is connected to the cam; During the axial sliding of the inner mold core, the root diameter section of the inner shrinkage block makes close contact with the inner mold core before the inner wall section.

[0014] Compared with the prior art, the beneficial effects of the present invention are: In this invention, a first forming module and a second forming module are respectively provided on a fixed mold base. The first forming module can cooperate with the diameter reduction unit to pre-reduced the diameter of the shell, so that the two ends of the shell can initially form a diameter reduction profile. The second forming module cooperates with the diameter reduction unit to precisely reduce the diameter of the shell, ensuring that the inner diameter of the shell after diameter reduction reaches the assembly accuracy and avoiding dimensional loss caused by a single large deformation. The main reducing unit can, on the one hand, use the extension and retraction of the hydraulic cylinder to pull the inner mold core and the inner reducing block to perform internal static support and shaping of the housing diameter. This internal rigid support can effectively correct ellipticity, prevent uneven wall thickness, and significantly improve roundness and coaxiality. On the other hand, the drive motor can drive the cam to rotate, so that the outer tube and the guide shaft can perform axial reciprocating motion. At this time, it can not only form dynamic shaping of the housing diameter, eliminate or significantly reduce springback and ensure dimensional stability after reducing diameter, but also use the relative sliding of the outer tube and the guide tube to achieve unidirectional deflection of the guide shaft, thereby achieving internal spinning of the housing diameter and ensuring dimensional stability after reducing diameter. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the mold closing mechanism in this invention; Figure 3 This is a schematic diagram of the diameter reduction unit in this invention; Figure 4 This is a schematic diagram of the diameter reduction device in this invention; Figure 5This is a schematic diagram of the slide groove in the present invention; Figure 6 This is a schematic diagram of the internal shrinkage block in this invention; In the diagram: 1. Fixed mold base; 11. Side mold frame; 12. Lower mold base; 13. Upper stamping base; 14. Connecting frame; 15. Guide post; 16. First forming module; 17. Second forming module; 2. Mold closing mechanism; 21. Spring support column; 22. Positioning post; 23. Closing plate; 3. Diameter reduction unit; 31. Support frame; 32. Limiting plate; 33. Hydraulic cylinder; 34. Fixed frame; 35. Cam; 36. Transmission rod; 4. Diameter reduction device; 41. Guide shaft; 42. Bushing; 43. Inner mold core; 44. Support spring; 45. Guide tube; 46. Slide groove; 47. Arc-shaped guide groove; 48. Anti-reverse flange; 49. Outer section tube; 5. Inner shrinkage block; 51. Root diameter section; 52. Inner wall section. Detailed Implementation

[0016] Please see Figures 1-6 In this embodiment of the invention, a composite mold assembly for three-way catalytic converter diameter reduction and shaping includes: The fixed mold base 1 is set as a rectangular cast iron base, with a lower mold base 12 arranged parallel to its upper end face; The two side mold frames 11 are symmetrically arranged and are symmetrically fixed on the fixed mold base 1 and located on both sides of the lower mold base 12. The upper stamping seat 13 is horizontally arranged above the fixed mold base 1. Connecting frames 14 are symmetrically fixed on both sides of the upper stamping seat 13. Guide holes are opened through the connecting frames 14, and guide posts 15 are vertically fixed on each of the side mold bases 11. The upper end of the guide post 15 is slidably connected to the guide hole. The first forming module 16 and the second forming module 17 are each composed of two mold plates distributed vertically. The lower mold plate is embedded and fixed in the lower mold base 12, and the upper mold plate is embedded and fixed in the upper stamping base 13. The two mold plates have forming contour cavities on their opposite surfaces. The forming contour cavities have tapered conical surfaces at both ends for reducing the diameter contour of the two ends of the shell. In addition, the cavity surfaces of the first forming module 16 and the second forming module 17 are coated with a wear-resistant coating to reduce the coefficient of friction and improve wear resistance. The mold closing mechanism 2 is located below the lower mold base 12. The mold closing mechanism 2 can control the lower mold base 12 to close and contact with the upper stamping base 13 to form a whole. Multiple diameter reduction units 3 are configured, and each diameter reduction unit 3 is located at two diameter reduction shaping ports of the first forming module 16 and the second forming module 17, respectively.

[0017] In this embodiment, a propulsion device for driving the upper stamping seat 13 to move downward is provided above the upper stamping seat 13; Furthermore, the fixed mold base 1 is equipped with a transfer robotic arm (not shown in the figure). The transfer robotic arm is used to transport the pre-formed shell in the first forming module 16 to the second forming module 17 for precise diameter reduction and shaping. With this configuration, the shell can be formed in steps through the first forming module 16 and the second forming module 17, avoiding dimensional loss caused by a single large deformation and ensuring that the inner diameter after diameter reduction accurately meets the assembly requirements. It should be noted that the tapered angle of the tapered surface in the first molding module 16 is 10°-20°, and the inner diameter of the straight section in the middle of the cavity is 1-1.5 mm larger than the inner diameter of the final product, leaving room for subsequent finishing; while the tapered angle of the cavity in the second molding module 17 is the final molding angle, and the inner diameter of the straight section is consistent with the required size of the finished product, with a tolerance of ±0.5 mm.

[0018] In a preferred embodiment, the mold clamping mechanism 2 includes: The spring support pillars 21 are arranged vertically and symmetrically. Each spring support pillar 21 is connected to the lower end face of the lower mold base 12, and the lower end of the spring support pillar 21 is slidably connected to the fixed mold base 1. Positioning pins 22 are fixed at the four corners of the upper end face of the lower mold base 12, and positioning holes corresponding to the positioning pins 22 are opened in the upper stamping base 13, so as to realize the precise positioning and mold closing of the lower mold base 12 and the upper stamping base 13. The mold plate 23 is horizontally set on the lower end face of the fixed mold base 1. The lower end of the spring support 21 is connected to the mold plate 23. The mold plate 23 is provided with a mold closing cylinder. Specifically, the housing is placed in the first molding module 16 and the second molding module 17 respectively. The mold closing cylinder pushes the lower mold base 12 to move upward until the end face of the lower mold base 12 is flush with the end face of the side mold frame 11. Then, one end of each diameter reduction unit 3 extends into the housing and the upper stamping seat 13 is pushed downward by the propulsion device, thereby realizing the initial mold closing of the upper stamping seat 13 and the lower mold base 12. After the mold closing is completed, the mold closing cylinder continues to apply the mold closing force to ensure that the upper stamping seat 13 and the lower mold base 12 are completely and tightly fitted.

[0019] In this embodiment, the diameter reduction unit 3 includes: The support frame 31 is horizontally slidably installed on one side of the side mold frame 11. Two limiting plates 32 are symmetrically fixed on the side mold frame 11 by bolts to limit the sliding movement of the support frame 31. Hydraulic cylinder 33 is horizontally fixed on the support frame 31; The diameter reduction device 4 is installed at the telescopic end of the hydraulic cylinder 33; in this way, the hydraulic cylinder 33 can drive the diameter reduction device 4 to extend into or detach from the housing under the telescopic action; the diameter reduction device 4 can form an internal rigid support for the housing. Compared with the traditional mold that only extrudes externally, the internal rigid support can effectively correct the ellipticity, prevent uneven wall thickness, and greatly improve the roundness and coaxiality. A fixing frame 34 is fixed on the side mold frame 11 and located below the support frame 31. Two guide rods are horizontally slidably connected to the fixing frame 34, and the other end of each guide rod is connected to the support frame 31. A cam 35 is rotatably mounted within the fixed frame 34. A transmission rod 36 is hinged to the cam 35, and the other end of the transmission rod 36 is connected to the guide rod. When the cam 35 rotates continuously, it can use the transmission rod 36 to push the support frame 31 to move radially and horizontally back and forth. The displacement distance is short and the movement frequency is high, so that the diameter reduction device 4 at the end of the hydraulic cylinder 33 can form a dynamic, micro-amplitude reciprocating shaping force within the housing. This dynamic loading can break the balance of the elastic recovery of the metal, causing the housing material to deform sufficiently, thereby eliminating or significantly reducing springback and ensuring dimensional stability after diameter reduction.

[0020] In this embodiment, the diameter reduction device 4 includes: The guide shaft 41 has one end coaxially connected to the telescopic end of the hydraulic cylinder 33; A bushing 42 is coaxially sleeved on the end of the guide shaft 41 away from the hydraulic cylinder 33. Multiple inner shrink blocks 5 are distributed circumferentially on the end of the bushing 42 away from the hydraulic cylinder 33, and each inner shrink block 5 is hinged to the bushing 42. The inner mold core 43 is fixed at the other end of the guide shaft 41. When the inner mold core 43 is in close contact with multiple inner shrink blocks 5, it can form a regular conical structure that is consistent with the inner contour of the shell diameter reduction shaping.

[0021] In this embodiment, a support spring 44 is provided on the guide shaft 41 and inside the bushing 42. The support spring 44 pushes the bushing 42 away from the inner mold core 43 in its natural state. Furthermore, the upper stamping seat 13 has a tube groove (not shown in the figure), and the bushing tube 42 is slidably positioned in the tube groove. Specifically, when the mold closing cylinder pushes the lower mold seat 12 upward until the end face of the lower mold seat 12 is flush with the end face of the side mold frame 11, the hydraulic cylinder 33 pushes the guide shaft 41 axially, so that the inner mold core 43 and the inner shrinking block 5 are fully inserted into the housing; then the upper stamping seat 13 moves downward and contacts and cooperates with the lower mold seat 12. At this time, part of the bushing tube 42 is inserted into the housing, and the other part is in the tube groove of the upper stamping seat 13; during the diameter reduction and shaping, the hydraulic cylinder 33 hydraulically contracts and pulls the guide shaft 41 to slide axially. When the end of the bushing tube 42 reaches the end of the tube groove, the bushing tube 42 stops sliding due to the limit. At this time, the guide shaft 41 continues to move axially, and the inner mold core 43 gradually contacts and cooperates with the inner shrinking block 5 until a regular conical structure is completely formed, thereby realizing the internal support and shaping of the housing; After the diameter reduction and shaping are completed, the hydraulic cylinder 33 extends hydraulically to realize the reverse sliding of the guide shaft 41. The guide shaft 41 gradually extends into the housing. At this time, the inner mold core 43 and the inner shrink block 5 gradually disengage. When the upper punch seat 13 moves upward and disengages from the lower mold seat 12, the hydraulic cylinder 33 can remove the diameter reduction device 4 from the housing under hydraulic contraction. It should be noted that the overall size of the diameter reduction device 4 in its natural state should be smaller than the inner diameter of the housing after the diameter reduction and shaping, so that the diameter reduction device 4 can be freely removed from the housing after shaping.

[0022] In a preferred embodiment, a guide tube 45 is horizontally fixed on the side mold frame 11, and an outer section tube 49 is horizontally rotatably connected to the support frame 31. One end of the outer section tube 49 extends into and is connected to the guide tube 45, and the guide shaft 41 is slidably connected to the outer section tube 49. A sliding groove 46 is provided on the inner wall of the guide tube 45. The guide shaft 41 is rotatably connected to the telescopic end of the hydraulic cylinder 33, and a guide pin is vertically fixed on the side wall of the outer section tube 49. The guide pin is slidably connected to the slide groove 46.

[0023] In this embodiment, the slide groove 46 is configured with a wave-shaped structure. Arc-shaped guide grooves 47 are provided at each corner of the slide groove 46 to provide a smooth transition surface, allowing the guide pin to move smoothly along the wave trajectory of the slide groove 46. Furthermore, a check flange 48 is provided on the inner wall of the slide groove 46 near the corner, similar to a one-way check structure of a limit block, to enable continuous unidirectional movement of the guide pin along the slide groove 46. Specifically, when the cam 35 rotates continuously, it can use the transmission rod 36 to push the support frame 31 radially and horizontally back to its original position. At this time, the outer section tube 49 on the support frame 31 and the guide shaft 4 at the end of the hydraulic cylinder 33... 1. Both reciprocate synchronously with the support frame 31. When the outer section tube 49 moves in a straight forward direction, the guide pin is forced to move along the curved trajectory of the slide groove 46. The lateral offset of the guide pin will generate a torque around the axis of the outer section tube 49, forcing the outer section tube 49 to deflect at a small angle to conform to the direction of the slide groove 46, so that the guide shaft 41 deflects continuously at a small angle with the outer section tube 49. When the outer section tube 49 moves in a straight reverse direction, at the corner, the arc-shaped guide groove 47 will guide the guide pin to continue sliding along the slide groove 46, while the anti-reverse flange 48 is used to prevent the guide pin from returning along the original wave trajectory, thereby realizing the continuous, unidirectional, step-by-step small-angle deflection of the guide shaft 41. With this configuration, the guide shaft 41 deflects by a small angle with each reciprocating motion. At this time, the end of the bushing 42 abuts against the tube groove. This deflection causes the inner shrinkage block 5 to generate supporting spin forming on the inner wall of the housing, thereby obtaining a high-precision formed inner wall. At the same time, the axial reciprocating motion itself provides dynamic shaping force. The combination of these two functions simultaneously completes multiple functions such as eliminating springback, uniform stress, and inner wall spin forming within one tooling cycle, significantly improving the quality and efficiency of diameter reduction forming.

[0024] In this embodiment, each of the inner shrinking blocks 5 is composed of two mutually hinged root diameter sections 51 and inner wall sections 52. A torsion spring is provided between the inner shrinking block 5 and the bushing tube 42 to ensure that each inner shrinking block 5 can retract into the axis of the bushing tube 42 in a natural state so that the subsequent diameter reduction device 4 can be safely removed from the shaped housing.

[0025] In this embodiment, a drive motor is installed below the fixing frame 34, and the output end of the drive motor is connected to the cam 35; During the axial sliding of the inner mold core 43, the root diameter section 51 of the inner shrinking block 5 makes close contact with the inner mold core 43 before the inner wall section 52. Specifically, in the shrinking shaping process, the inner mold core 43 first cooperates with the root diameter section 51 to support and shape the shell port area. This area has small deformation and the highest dimensional accuracy requirements. The inner mold core 43 first expands the root diameter section 51, so that the shell port area first obtains rigid support. Then, the inner mold core 43 cooperates with the inner wall section 52 to shape the inner wall, avoiding material deformation interference caused by the simultaneous force on the port and the inner wall. Compared with the traditional technology, the inner shrinking block 5 is usually an integral rigid structure. When the inner mold core 43 is axially advanced, the entire inner shrinking block 5 is expanded at the same time. This device avoids the inner wall of the port being subjected to excessive instantaneous radial pressure due to the integral inner shrinking block 5, which could cause microcracks or wall thickness reduction. It allows the port area to obtain an intermediate transition support force in advance. After the shell material is initially stabilized, the expansion force of the inner wall section 52 is mainly transmitted through the inner wall, improving the shaping accuracy. Furthermore, the inner mold core 43 and the inner shrinking block 5 can form various contact fit patterns by changing their relative positions (i.e., by controlling the extension and retraction of the hydraulic cylinder 33). Under different contact patterns, the cam 35 can drive the guide shaft 41 to move radially and horizontally back and forth to gradually spin the shell. Each reciprocation can cause a slight change in the contact pattern between the inner mold core 43 and the inner shrinking block 5 (e.g., from incomplete contact to complete contact), thereby achieving gradual spinning of the shell material from local to overall. Compared with one-time large deformation extrusion, gradual spinning significantly reduces the peak stress of a single loading, avoiding buckling instability or local cracking of the shell during the diameter reduction process.

[0026] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter, characterized in that, It includes: A fixed mold base (1) has a lower mold base (12) arranged parallel to its upper end face; The two side mold frames (11) are symmetrically arranged and are symmetrically fixed on the fixed mold base (1) and located on both sides of the lower mold base (12); The upper stamping seat (13) is horizontally set above the fixed mold base (1). Connecting frames (14) are symmetrically fixed on both sides of the upper stamping seat (13). Guide holes are opened through the connecting frames (14), and guide posts (15) are vertically fixed on each side mold base (11). The upper end of the guide post (15) is slidably connected to the guide hole. The first forming module (16) and the second forming module (17) are both composed of two model plates distributed vertically. The lower model plate is embedded and fixed in the lower mold base (12), and the upper model plate is embedded and fixed in the upper stamping base (13). The mold closing mechanism (2) is located below the lower mold base (12); Multiple diameter reduction units (3) are configured, and each diameter reduction unit (3) is located at the two diameter reduction shaping ports of the first molding module (16) and the second molding module (17).

2. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 1, characterized in that: A propulsion device for driving the upper stamping seat (13) to move downward is provided above the upper stamping seat (13); Furthermore, the fixed mold base (1) is provided with a transfer robotic arm, which is used to transport the pre-formed shell in the first molding module (16) to the second molding module (17) for precise diameter reduction and shaping.

3. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 1, characterized in that, The mold closing mechanism (2) includes: The spring support (21) consists of multiple spring supports arranged vertically and symmetrically. Each spring support (21) is connected to the lower end face of the lower mold base (12), and the lower end of the spring support (21) is slidably connected through the fixed mold base (1). Positioning pins (22) are fixed at the four corners of the upper end face of the lower die base (12), and positioning holes corresponding to the positioning pins (22) are provided in the upper stamping base (13); The template (23) is horizontally set on the lower end face of the fixed mold base (1), and the lower end of the spring support (21) is connected to the template (23).

4. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 3, characterized in that, The reduced diameter unit (3) includes: A support frame (31) is horizontally slidably installed on one side of a side mold frame (11), and two limiting plates (32) are symmetrically fixed on the side mold frame (11) by bolts. The hydraulic cylinder (33) is horizontally fixed on the support frame (31); A diameter reduction device (4) is installed at the telescopic end of the hydraulic cylinder (33); A fixing frame (34) is fixed on the side mold frame (11) and located below the support frame (31). Two guide rods are horizontally slidably connected on the fixing frame (34), and the other end of each guide rod is connected to the support frame (31). A cam (35) is rotatably mounted inside the fixed frame (34), and a transmission rod (36) is hinged to the cam (35). The other end of the transmission rod (36) is connected to the guide rod.

5. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 4, characterized in that, The diameter reduction device (4) includes: The guide shaft (41) has one end coaxially connected to the telescopic end of the hydraulic cylinder (33); A bushing (42) is coaxially sleeved on the end of the guide shaft (41) away from the hydraulic cylinder (33). Multiple inner shrink blocks (5) are distributed circumferentially on the end of the bushing (42) away from the hydraulic cylinder (33), and each inner shrink block (5) is hinged to the bushing (42). The inner mold core (43) is fixed at the other end of the guide shaft (41).

6. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 5, characterized in that: A support spring (44) is fitted on the guide shaft (41) and inside the bushing (42). The support spring (44) pushes the bushing (42) away from the inner mold core (43) in its natural state. Furthermore, a tube groove is provided inside the upper stamping seat (13), and the bushing tube (42) is slidably positioned inside the tube groove.

7. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 6, characterized in that: A guide tube (45) is horizontally fixed on the side mold frame (11), and an outer section tube (49) is horizontally rotatably connected on the support frame (31). One end of the outer section tube (49) extends into and is connected to the guide tube (45), and the guide shaft (41) is slidably connected to the outer section tube (49). A sliding groove (46) is provided on the inner wall of the guide tube (45). The guide shaft (41) is rotatably connected to the telescopic end of the hydraulic cylinder (33), and a guide pin is vertically fixed on the side wall of the outer section tube (49), and the guide pin is slidably connected to the slide groove (46).

8. The composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 7, characterized in that: The slide (46) is configured with a wave-shaped structure. Each corner of the slide (46) is provided with an arc-shaped guide groove (47), and the inner wall of the slide (46) is provided with a backstop protrusion (48) on the side near the corner.

9. A composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 5, characterized in that: Each of the inner shrink blocks (5) consists of two mutually hinged root diameter sections (51) and inner wall sections (52), and a torsion spring is provided between the inner shrink blocks (5) and the bushing (42).

10. A composite mold assembly for reducing and shaping the diameter of a three-way catalytic converter according to claim 9, characterized in that: A drive motor is installed below the fixed frame (34), and the output end of the drive motor is connected to the cam (35); During the axial sliding of the inner mold core (43), the root diameter section (51) in the inner shrinkage block (5) makes close contact with the inner mold core (43) before the inner wall section (52).

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