Cold extrusion forming die for aluminum alloy connecting knuckle

Abstract

A cold extrusion forming die for an aluminum alloy connecting yoke, comprising an upper die assembly and a lower die assembly, the upper die assembly comprising an upper punch, and the lower die assembly comprising a lower cavity die; the depth of the cavity of the lower cavity die is greater than or equal to the length of the yoke forging after forming, and the lower part of the cavity is provided with yoke cavities for forming two yoke ends of the yoke forging; the lower part of the lower cavity die is further provided with a round top ejection hole and two square top ejection holes, the two square top ejection holes are symmetrically arranged below the two yoke cavities with respect to the round top ejection hole, and the square top ejection holes on the same side and the yoke cavities are vertically aligned and communicated; the lower die assembly further comprises a round top ejector and two square top ejectors, the lower end of the round top ejector and the lower end of the square top ejector are installed on the ejector fixing block; the round top ejector is inserted into the round top ejection hole upward, and the square top ejector is inserted into the square top ejection hole upward. The utility model can improve the production efficiency and reduce the production cost under the premise of ensuring the quality of the parts.

Description

Technical Field

[0001] This utility model belongs to the category of, specifically relating to, a cold extrusion forming die for an aluminum alloy connecting fork. Background Technology

[0002] The connecting fork acts as a bridge for torque transmission in a car's steering wheel, transferring the rotational torque input from the steering wheel to the steering gear via a spline structure. For new energy vehicles, the connecting fork not only transmits torque but also incorporates sensor mounting surfaces. These sensors provide real-time feedback on the vehicle's steering conditions, thereby optimizing and simulating the driver's steering wheel feel. With the rapid development of the new energy vehicle industry, the demand for lightweight vehicles is increasing. Aluminum alloy connecting forks (density 2.7g / cm³) are used. 3 Compared to steel components, it can achieve a weight reduction of 40%-50%, which not only directly reduces the inertia of the steering system, but also improves the response speed of the electric power steering motor (the measured delay of the EPS system is reduced by 0.05-0.1s), providing important support for the performance improvement of new energy vehicles.

[0003] Currently, the processing of aluminum alloy connecting forks typically involves extruding round bars using floating extrusion dies to form fork blanks, followed by additional machining to obtain the final aluminum alloy connecting fork product. However, this traditional processing method has many drawbacks in practical applications, limiting its further development and application.

[0004] The following are the main drawbacks when using floating extrusion dies for extrusion forming: (1) There will be burrs and flash on the parting surface of the blank. These burrs and flash not only affect the appearance quality of the parts, but may also cause other problems in the subsequent use, such as increased wear and affecting assembly. (2) In order to ensure that the blank can remain stably in the die during the upward process of the upper die after extrusion, a resistance groove is usually designed on the inner wall of the die to increase the friction with the blank. However, although this design solves the problem of blank retention, it has a negative impact on the surface quality of the outer circle of the blank, resulting in scratches, unevenness and other defects on the outer circle surface, which in turn affects the overall quality of the part. (3) During the floating extrusion process, ejection is usually carried out by setting an ejector from inside the blank. However, due to the limited solid wall thickness of the blank (6±0.25mm), the fork end of the blank often undergoes opening deformation due to insufficient strength after ejection. This deformation not only affects the dimensional accuracy of the part, but may also lead to functional failures in the part during subsequent use.

[0005] To address issues (1) and (2) above, the current solution is to perform additional machining on the outer diameter of the blank after forming to remove burrs and flash, and to ensure the surface quality and dimensional accuracy of the parts. For issue (3), a straightening process is required to correct the deformation of the blank. However, these additional machining processes not only increase production costs but also reduce production efficiency, making it difficult for this machining method to meet the market demand for efficient and low-cost production of aluminum alloy connecting forks.

[0006] Therefore, there is an urgent need for a new processing method or mold structure that can improve production efficiency and reduce production costs while ensuring the quality of parts, so as to adapt to the rapid development of the new energy vehicle industry. Utility Model Content

[0007] The purpose of this invention is to provide a cold extrusion forming die for aluminum alloy connecting forks, which can improve production efficiency and reduce production costs while ensuring part quality, so as to adapt to the rapid development of the new energy vehicle industry.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a cold extrusion forming die for an aluminum alloy connecting fork, comprising an upper die assembly and a lower die assembly. The upper die assembly includes an upper punch, and the lower die assembly includes a lower die. The upper punch enters the cavity of the lower die to extrude the blank. The cavity depth of the lower die is greater than or equal to the length of the fork forging after forming. A fork cavity is provided at the lower part of the die cavity for forming the two fork ends of the fork forging. The lower part of the lower die also provides a dome outlet and two square outlets. The two square outlets are symmetrically arranged below the two fork cavities about the dome outlet, and the square outlets on the same side are aligned vertically and connected to the fork cavity. The lower mold assembly also includes a dome ejector and two square ejectors. The lower ends of the dome ejector and the square ejectors are mounted on the ejector fixing block. The dome ejector is inserted upward into the dome outlet hole, and the square ejectors are inserted upward into the corresponding square outlet hole.

[0009] Furthermore, the lower die is pressed into the lower die middle ring, and the lower die middle ring is assembled into the lower die outer ring.

[0010] Furthermore, the outer circular surface of the lower die is a conical surface, and a lower die positioning groove extending axially and penetrating the upper and lower end faces is provided on the conical surface. The inner wall of the lower die middle ring is provided with a lower die middle ring positioning groove. The lower die positioning groove and the lower die middle ring positioning groove can form a positioning hole. The lower die and the lower die middle ring are circumferentially positioned by inserting a positioning pin into the positioning hole.

[0011] Furthermore, a lower mold pad is provided inside the outer ring of the lower mold, and the bottom surfaces of the lower die and the lower mold middle ring are in contact with the upper end surface of the lower mold pad; the lower mold pad is provided with through holes for the dome and the square dome to pass through.

[0012] Furthermore, the lower mold assembly also includes an intermediate template, the lower mold outer ring and the intermediate template are fixedly connected, and the intermediate template is provided with through holes through which the dome and square dome pass.

[0013] Furthermore, the lower mold assembly also includes a mold base and a lower mold plate. The upper end face of the mold base and the lower end face of the lower mold plate are in close contact. The ejector fixing block is installed in the through hole of the mold base and supported on the ejector pad block in the through hole. A push rod is slidably provided on the lower mold plate. The push rod is located below the ejector pad block and is used to push the ejector pad block upward.

[0014] Furthermore, the lower template is provided with a limiting member, the top rod is movably inserted into the limiting member, and the upper end of the top rod is provided with a limiting ring, which can be locked onto the upper end face of the limiting member.

[0015] Furthermore, the limiting component is a nut with external threads, which is threaded to the lower template. The push rod passes through the inner hole of the nut, and the upper end of the push rod is provided with a T-shaped head for locking onto the upper end face of the nut.

[0016] Furthermore, the lower template and the intermediate template are connected by equal-height screws.

[0017] Furthermore, the upper punch has several protrusions on its circumferential surface to form the spline structure of the inner hole of the aluminum alloy connecting joint fork.

[0018] The beneficial effects of this utility model are as follows: In this utility model, the fork cavity used to form the fork end in the lower die is located in the lower part of the lower die cavity. In this way, the fork forging is inverted and formed in the lower die cavity with the fork end facing down. During the ejection of the fork forging, the fork end is located in the lower die cavity, and there will be no problem of the fork end opening and deformation. No additional straightening process is required afterward.

[0019] Moreover, since the fork forging is entirely located within the lower die cavity, the contact area between the fork forging and the lower die cavity is larger, providing sufficient frictional resistance. Therefore, there is no need to set resistance grooves in the lower die cavity. The outer surface of the fork forging is smooth and flat with high precision. After subsequent ejection, there is no need to machine the outer surface of the fork forging, saving processes. On the other hand, overflow flash can be eliminated from the fork end, and the machining allowance at the fork end is small (in order to keep the forging in the lower die, the upper fork position needs to be designed with overflow, resulting in a large machining allowance), further saving processes.

[0020] Compared to finished aluminum alloy connecting fork parts, the forged fork produced using the cold extrusion forming die of this invention requires only minor machining on the end faces, fork end lugs, and through holes connecting the fork end and spline; the rest is entirely forged. Therefore, the cold extrusion forming die of this invention utilizes the near-net-shape forming characteristics of materials to create a high-precision part requiring minimal machining. This shortens the processing cycle, improves production efficiency, reduces production costs, and is easy to operate, facilitating mechanization and automation, thereby enhancing market competitiveness. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the aluminum alloy connecting fork forging formed by the cold extrusion forming die of the present invention; Figure 2 This is a schematic diagram of the overall assembly of the cold extrusion forming die of this utility model; Figure 3 This is a schematic diagram of the upper punch of the cold extrusion forming die of the present invention; Figure 4 This is a schematic diagram of the lower die of the cold extrusion forming die of this utility model; Figure 5 This is a top view of the lower die of the cold extrusion forming die of this utility model; Figure 6 for Figure 5 AA section view in the middle; Figure 7 This is a schematic diagram of the structure of the dome part of the cold extrusion forming die of this utility model; Figure 8 This is a schematic diagram of the square ejector of the cold extrusion forming die of this utility model; Figure 9 This is a schematic diagram of the ejector fixing hole of the cold extrusion forming die of this utility model; The markings in the diagram are: 1. Upper mold plate, 2. Upper mold pad, 3. Upper mold sleeve, 4. Upper punch, 401. Thrust, 5. Lower die, 501. Lower mold cavity, 502. Lower die positioning groove, 503. Dome ejector hole, 504. Square ejector hole, 505. Fork cavity, 6. Lower mold middle ring, 7. Lower mold outer ring, 8. Lower mold pad, 9. Dome ejector, 10. Square ejector, 11. Intermediate mold plate, 12. Ejector fixing block, 1201. Round mounting hole, 1202. Square mounting hole, 13. Mold base, 14. Ejector pad, 15. Lower mold plate, 16. Ejector rod, 17. Nut, 18. Equal height screw, 19. Guide sleeve, 20. Guide post; 100. Fork section forging; 200. Fork end. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention in any way.

[0023] See attached document Figure 2-8 As shown, a cold extrusion forming die for an aluminum alloy connecting fork includes an upper die assembly and a lower die assembly.

[0024] like Figure 2 As shown, the upper mold assembly includes an upper template 1, an upper mold pad 2, an upper mold sleeve 3, and an upper punch 4. The upper mold sleeve 3 has a through hole, which is a stepped hole with a diameter decreasing from top to bottom. The stepped hole has two sections, with the diameter of the upper section being larger than that of the lower section. The upper mold pad 2 is installed in the upper section of the stepped hole in the upper mold sleeve 3, and the upper mold pad 2 is flush with the upper end face of the upper mold sleeve 3. The upper punch 4 is installed in the lower section of the stepped hole in the upper mold sleeve 3 and transitionally fits with the upper mold sleeve 3. The upper end face of the upper punch 4 abuts against the lower surface of the upper mold pad 2, and the lower end face of the upper punch 4 extends downwards from the through hole of the upper mold sleeve 3 by a certain length.

[0025] The upper punch 4 has a protrusion 401 on its circumferential surface, which is used to squeeze the blank during the mold closing process and form a spline structure inside the connecting fork in the inner hole formed by the blank.

[0026] The assembly sequence of the upper mold assembly is as follows: First, the upper punch 4 is inserted into the lower stepped hole of the upper mold sleeve 3 from top to bottom, and is limited by the stepped surface of the lower stepped hole to prevent the upper punch 4 from falling out; second, the upper mold pad 2 is inserted into the upper stepped hole of the upper mold sleeve 3 from top to bottom, and is in contact with the upper end face of the upper punch 4; finally, the upper mold sleeve 3 is fixed to the lower surface of the upper template 1 with screws, and the upper mold pad 2 is clamped between the upper template 1 and the upper punch 4.

[0027] like Figure 2 As shown, the lower mold assembly includes a lower die 5, a lower mold middle ring 6, a lower mold outer ring 7, a lower mold pad 8, a round ejector 9, a square ejector 10, an intermediate template 11, an ejector fixing block 12, a mold base 13, an ejector pad 14, a lower template 15, and an ejector rod 16.

[0028] like Figure 4 , 5 As shown in Figures 6 and 7, the lower die 5 has a lower die cavity 501 for forming. Figure 1The aluminum alloy connecting fork forging 100 has a lower part of the lower die cavity 501 used to form the fork ends 200 on both sides of the fork forging 100. Therefore, after the fork forging 100 is formed in the lower die cavity 501, it is in a state where the fork ends 200 face downwards. Thus, the entire fork forging 100 is completely located in the lower die cavity 501 of the lower die 5, and no burrs or flash are generated at the root of the fork ends 200 of the fork forging 100. The lower part of the lower die 5 is also provided with ejection holes for the ejector to pass through. There are two types of ejection holes: a round ejection hole 503 and a square ejection hole 504. The round ejection hole 503 is centrally located and is used for the round ejector 9 to pass upwards and press against the position between the two fork ends 200 of the fork forging 100. Two square ejection holes 504 are provided, symmetrically distributed on both sides of the round ejection hole 503, and are used for the square ejector 10 to pass upwards and press against the end faces of the two fork ends 200 of the fork forging 100, thereby pushing the fork forging 100 upwards under the combined action of the three ejectors. The outer circular surface of the lower die 5 is also provided with an axially extending lower die positioning groove 502 with an arc-shaped cross-section. Furthermore, the outer circular surface of the lower die 5 is a conical surface, with a smaller upper surface and a larger lower surface.

[0029] The lower die 5, lower die middle ring 6, and lower die outer ring 7 are sequentially fitted together from the inside out. The inner wall of the lower die middle ring 6 has a lower die middle ring positioning groove with an arc-shaped cross-section. The lower die middle ring positioning groove and the lower die positioning groove 502 are correspondingly arranged and can complement each other to form a positioning hole with a circular cross-section. After a positioning pin is inserted into the positioning hole, part of the positioning pin is located in the lower die positioning groove 502, and the other part of the positioning pin is located in the lower die middle ring positioning groove, thereby preventing the lower die 5 and the lower die middle ring 6 from rotating relative to each other. Furthermore, the lower ends of the lower die 5 and the lower die middle ring 6 are supported on the upper end of the lower die pad 8, and the lower die pad 8 is located inside the lower die outer ring 7. The lower die outer ring 7 and the intermediate template 11 are connected together by screws, so that the lower die pad 8 is supported on the upper end of the intermediate template 11. The intermediate template 11 is supported on the upper end of the mold base 13, and the mold base 13 is supported on the lower template 15. The lower template 15 and the intermediate template 11 are connected together by equal-height screws 18.

[0030] The structures of the dome-shaped component 9 and the square dome-shaped component 10 are as follows: Figure 7 , 8 As shown, in the lower mold assembly, the lower ends of one round ejector 9 and two square ejector 10 are mounted on an ejector fixing block 12. Figure 9 As shown, the top piece fixing block 12 is provided with a round mounting hole 1201 and two square mounting holes 1202. The two square mounting holes 1202 are located on both sides of the round mounting hole 1201 and are arranged opposite each other. The lower end of the round top piece 9 is installed in the round mounting hole 1201 and the lower end of the square top piece 10 is installed in the square mounting hole 1202.

[0031] The ejector fixing block 12 and ejector pad 14, which are used to install the round ejector 9 and the square ejector 10, are slidably arranged in the mold base 13. The ejector fixing block 12 is supported on the ejector pad 14, and the round ejector 9 and the square ejector 10 extend into the corresponding ejection holes in the lower die 54 after passing through the intermediate template 11 and the lower die pad 8.

[0032] The lower template 15 has a through hole located below the ejector fixing block 12. The ejector rod 16 passes through the through hole and is used to push the ejector pad 14 and the ejector fixing block 12 upward under the pushing action of the lower ejector cylinder.

[0033] Furthermore, a nut 17 is installed on the through hole of the lower template 15. The nut 17 has external threads and is threadedly connected to the through hole. The inner hole of the nut 17 is a smooth hole, through which the push rod 16 passes and slides up and down. The upper end of the push rod 16 is provided with a T-shaped head, which can be locked onto the upper end of the nut 17 to prevent the push rod 16 from falling off the nut 17.

[0034] The assembly sequence of the lower mold assembly is as follows: (1) The lower die middle ring 6 and the lower die outer ring 7 are thermally fitted together, the lower die 5 is tapered and pressed into the lower die middle ring 6, and the lower die 5 and the lower die middle ring 6 are circumferentially positioned using locating pins; (2) The lower mold pad 8 is installed in the lower part of the lower mold outer ring 7, and the lower mold outer ring 7 and the intermediate template 11 are fixed with screws, thereby fixing the lower die 5, the lower mold middle ring 6, the lower mold outer ring 7, the lower mold pad 8 and the intermediate template 11 together. (3) The dome assembly 9, the square dome assembly 10 and the dome assembly fixing block 12 are slightly interference fit; (4) Secure the mold base 13 and the lower template 15 with screws; (5) Insert the ejector fixing block 12 and ejector pad 14 into the through hole of the mold base 13 from above. Then, insert the upper ends of the round ejector 9 and the square ejector 10 through the intermediate template 11 and the lower mold pad 8 into the round mounting hole 503 and the square mounting hole 504 of the lower die 5. Then, use the equal height screw 18 to fix the intermediate template 11 and the lower template 15 together. (6) After the top rod 16 passes through the inner hole of the nut 17 from top to bottom, the nut 17 is screwed onto the lower template 15.

[0035] The upper and lower die assemblies of this utility model's cold extrusion forming die are guided by the sliding fit of guide posts 20 and guide sleeves 19 when moving relative to each other vertically, ensuring the positional accuracy of the upper and lower die assemblies. Guide sleeves 19 are disposed on the upper template 1 and the intermediate template 11, corresponding vertically. Guide posts 20 are fixed within the guide sleeves 19 of the upper template 1, and the lower ends of guide posts 20 are slidably inserted into the guide sleeves 19 of the intermediate template 11.

[0036] The cold extrusion forming die of this invention operates in the following sequence when forming an aluminum alloy connecting fork: (1) The upper mold assembly and the lower mold assembly are aligned by the cooperation of the guide sleeve 19 and the guide post 20. The upper template 1 of the upper mold assembly is fixed to the slide of the hydraulic press by bolts and the pressure plate. The lower template 15 of the lower mold assembly is fixed to the lower mold platform of the hydraulic press by bolts and the pressure plate. (2) The aluminum alloy blank is placed into the cavity 501 of the lower die 5. The slide of the hydraulic press drives the upper die assembly to move downward as a whole. The upper punch 4 contacts the aluminum alloy blank. As the slide continues to move downward, the aluminum alloy blank is extruded and formed under the action of the upper punch 4. After extrusion, the hydraulic press drives the slide to return to the position. The lower cylinder of the hydraulic press pushes out and pushes the ejector rod 16 upward. The ejector rod 16 pushes the ejector pad 14 upward, and pushes the round ejector 9 and the square ejector 10 upward. The round ejector 9 and the square ejector 10 push the formed fork forging 100 out of the lower die 5. (3) After the ejection action is completed, remove the fork forging 100.

[0037] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific implementation of this utility model with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model are within the protection scope of the pending claims.

Claims

1. A cold extrusion forming die for an aluminum alloy connecting fork, comprising an upper die assembly and a lower die assembly, the upper die assembly comprising an upper punch (4), the lower die assembly comprising a lower die (5), the upper punch (4) entering the lower die cavity (501) of the lower die (5) to extrude a blank; characterized in that: The lower die cavity (501) of the lower die (5) has a depth greater than or equal to the length of the forked section forging (100) after forming. The lower part of the lower die cavity (501) is provided with two fork cavities (505), which are used to form the two fork ends (200) of the forked section forging (100). The lower part of the lower die (5) is also provided with a dome outlet hole (503) and two square outlet holes (504). The two square outlet holes (504) are symmetrically arranged below the two fork cavities about the dome outlet hole (503), and the square outlet holes (504) and the fork cavity (505) on the same side are aligned and connected vertically. The lower mold assembly also includes a dome ejector (9) and two square ejectors (10). The lower ends of the dome ejector (9) and the square ejectors (10) are mounted on the ejector fixing block (12). The dome ejector (9) is inserted upward into the dome outlet hole (503) and is used to press against the position between the two fork ends (200) of the fork forging (100). The square ejectors (10) are inserted upward into the corresponding square ejector hole (504) and are used to press against the end face of the corresponding fork end (200) of the fork forging (100).

2. The cold extrusion forming die according to claim 1, characterized in that: The lower die (5) is pressed into the lower die middle ring (6), and the lower die middle ring (6) is assembled into the lower die outer ring (7).

3. The cold extrusion forming die according to claim 2, characterized in that: The outer circular surface of the lower die (5) is a conical surface, and a lower die positioning groove (502) is provided on the conical surface, extending axially and penetrating the upper and lower end faces. The inner wall of the lower die middle ring (6) is provided with a lower die middle ring positioning groove. The lower die positioning groove (502) and the lower die middle ring positioning groove can form a positioning hole. The lower die (5) and the lower die middle ring (6) are circumferentially positioned by inserting a positioning pin into the positioning hole.

4. The cold extrusion forming die according to claim 2, characterized in that: The lower mold outer ring (7) is also provided with a lower mold pad (8), and the bottom surfaces of the lower die (5) and the lower mold middle ring (6) are in contact with the upper end surface of the lower mold pad (8); the lower mold pad (8) is provided with through holes for the dome part (9) and the square dome part (10) to pass through.

5. The cold extrusion forming die according to claim 2, characterized in that: The lower mold assembly also includes an intermediate template (11), the lower mold outer ring (7) and the upper end face of the intermediate template (11) are fixedly connected, and the intermediate template (11) is provided with through holes for the dome piece (9) and the square dome piece (10) to pass through.

6. The cold extrusion forming die according to claim 5, characterized in that: The lower mold assembly also includes a mold base (13) and a lower template (15). The upper end face of the mold base (13) and the lower end face of the lower template (11) are in contact. The ejector fixing block (12) is installed in the through hole of the mold base (13) and supported on the ejector pad (14) in the through hole. A push rod (16) is slidably provided on the lower template (15). The push rod (16) is located below the ejector pad (14) and is used to push the ejector pad (14) upward.

7. The cold extrusion forming die according to claim 6, characterized in that: The lower template (15) is provided with a limiting member, the top rod (16) is movably inserted into the limiting member, and the upper end of the top rod (16) is provided with a limiting ring, which can be locked onto the upper end face of the limiting member.

8. The cold extrusion forming die according to claim 7, characterized in that: The limiting component is a nut (17), which has an external thread and is threaded to the lower template (15). The push rod (16) passes through the inner hole of the nut (17), and the upper end of the push rod (16) is provided with a T-shaped head for locking onto the upper end face of the nut (17).

9. The cold extrusion forming die according to claim 6, characterized in that: The lower template (15) and the intermediate template (11) are connected by equal-height screws (18).

10. The cold extrusion forming die according to claim 1, characterized in that: The upper punch (4) has several protrusions (401) on its circumferential surface, which are used to form the spline structure of the inner hole of the aluminum alloy connecting joint fork.

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