A one-piece steering knuckle variable direction forming process with tie rod arms and steering arms

Abstract

The application provides a steering knuckle variable direction forming process with a pull rod arm and a steering arm, and comprises the following steps: S1, heating and horizontally placing a blank, and radially flattening; S2, compound extruding the flattened blank to form a disc part, a shaft part, a first straight arm and a second straight arm; S3, horizontally placing the blank formed in the step S2 into a semi-closed pre-forging die, and forming the first straight arm into a pull rod arm and an ear part of the pull rod arm by pressing the upper die, and meanwhile, the second straight arm is extruded to further separate a steering arm blank; S4, vertically placing the blank formed in the step S3 into a semi-closed final forging die to form a required steering arm shape of a final forging part, and completing the final forging of the steering knuckle. The blank extruded from the steering arm part is used as a front preparation of the steering arm of the final forging part, thus avoiding the large tensile stress generated by the existing bending process and the hidden danger of the root crack of the steering arm, and making the mechanical property of the formed steering knuckle with the pull rod arm and the steering arm more reliable.

Description

Technical Field

[0001] This invention relates to the field of steering knuckle technology, and more particularly to an integral steering knuckle forming process with tie rod arm and steering arm. Background Technology

[0002] During driving, a car frequently needs to change its direction of travel (steering). Typically, when a vehicle is turning, the driver applies a steering torque to the steering wheel. This torque travels through the steering shaft, drive shaft, and steering gear. After being amplified by the steering gear, the torque is transmitted to the steering rocker arm, then through the steering tie rod to the steering knuckle and the steering arm on the steering knuckle, and finally to the wheel hub, causing the wheels to turn. The steering arm is the final stage of force transmission in the steering transmission system. In current automotive design, the steering knuckle is generally forged as a single piece, undergoing multiple processes such as heating, pre-forging, molding, shaping, and trimming to achieve initial forming before machining. The lugs, disc (flange), and rod of the steering knuckle are a single integral structure, while the steering arm is connected to the steering knuckle after machining via bolts or ball joints.

[0003] To reduce product weight, production costs, and manufacturing and maintenance difficulties, some steering knuckles integrate the steering arm and steering knuckle into one unit. For example, patent application number 202122486200.0 discloses a steering knuckle that integrates a steering trapezoidal arm. Another example is the invention patent "Integral Steering Knuckle Device" (patent application number CN93104332), which discloses a steering knuckle with a steering arm and a steering tie rod arm and provides a forging process. However, judging from its process diagram, there is still room for further improvement in material utilization.

[0004] Another Chinese invention patent, "Automotive Steering Knuckle Integrated with Steering Arm and Its Processing Technology" (patent application number 201710885583.4), is also an integrated steering knuckle with two arms in one segment. However, its disclosed forming process also has shortcomings. In the bending process, due to the small bending radius and large bending angle, cracks may occur at the root of the steering arm, affecting the yield. In subsequent use, cracks may also occur at the root due to the complex loads borne by the steering knuckle. Summary of the Invention

[0005] In view of this, the present invention proposes an integral steering knuckle deflection forming process with tie rod arm and steering arm. Compared with the existing bending forming process, it can avoid the risk of cracks at the root of the steering arm during bending and improve the mechanical performance of the steering knuckle.

[0006] The technical solution of this invention is implemented as follows:

[0007] This invention provides a forming process for an integral steering knuckle with a tie rod arm and a steering arm, comprising the following steps:

[0008] S1. Heat the billet to the forging temperature, lay it horizontally, and flatten it radially by free forging.

[0009] S2. The flattened blank is placed into the extrusion cavity for compound extrusion to form the disc part and the shaft part, and the first straight arm and the second straight arm are extruded.

[0010] S3. Place the blank formed in step S2 into a semi-closed pre-forging cavity. Press down with the upper die to form the first straight arm into a tie rod arm and its ear. At the same time, the second straight arm is squeezed to further separate the steering arm blank.

[0011] S4. Change the workpiece orientation and place the billet formed in step S3 into the semi-closed final forging cavity to form the steering arm shape required by the final forging, thus completing the final forging of the steering knuckle.

[0012] Based on the above technical solution, preferably, in step S2, the disc and shaft are formed into the shape required by the final forging in the compound extrusion, and in step S3, the first straight arm is pre-forged into the shape required by the tie rod arm and its ear.

[0013] Based on the above technical solution, preferably, in the material separation operation of the first straight arm and the second straight arm in the compound extrusion, the volume of the first straight arm and the second straight arm is 5% to 10% larger than the actual volume of the corresponding ear and arm of the final forging, the width of the first straight arm and the second straight arm is 100% to 110% of the maximum width of the corresponding ear of the final forging, and the thickness of the first straight arm and the second straight arm is 90% to 100% of the maximum thickness of the corresponding ear of the final forging.

[0014] Based on the above technical solution, preferably, step S3 includes a pre-forging upper die and a pre-forging lower die for pre-forging forming, wherein the pre-forging upper die includes a first upper module and a second upper module arranged on the left and right sides;

[0015] The surface of the first upper module is provided with a first upper cavity, and the surface of the pre-forging lower die is provided with a first lower cavity that mates with the first upper cavity. The first upper cavity and the first lower cavity are used to press down the formed shaft and disc. The top surface of the first upper module is provided with a nitrogen spring that is connected to the upper die frame.

[0016] The surface of the second upper module is provided with a first forging upper cavity, and the surface of the pre-forging lower die is provided with a first forging lower cavity. The first forging upper cavity and the first forging lower cavity cooperate with each other to complete the final forging of the tie rod arm and its ear.

[0017] An extrusion structure is provided between the second upper module and the pre-forging lower die. The extrusion structure is used to extrude the second straight arm and further separate the blank corresponding to the steering arm.

[0018] Furthermore, preferably, the clamping force provided by the nitrogen spring must exceed the maximum compressive deformation force by 5% to 10%.

[0019] Furthermore, preferably, a flash groove is provided on the outer side of both the first forging upper cavity and the first forging lower cavity.

[0020] Based on the above technical solution, preferably, the extrusion structure includes an insert disposed on the second upper module and a first cavity disposed on the pre-forging lower die;

[0021] The thickness of the insert is the same as the thickness of the second straight arm, the width is 65% to 85% of the length of the second straight arm, and the height must be such that when the second upper module and the pre-forging lower die are fully closed, the billet is squeezed downward into 75% to 85% of its volume. The left end face of the insert is aligned with the top of the second straight arm, and the insert is located directly above the second straight arm.

[0022] The depth of the first cavity is approximately 80% to 100% of the length of the final forged steering arm, the thickness of the first cavity is consistent with the thickness of the second straight arm, and the width is adapted to the width of the insert.

[0023] Furthermore, preferably, the left end face of the insert is provided with a draft angle of 1°~2°, and the right end face of the insert is provided with a certain tilt angle α, where the value of α ranges from (90°-b+c)+3°~5°, where b represents the bending angle of the steering arm and c represents the draft angle or the angle of the conical surface.

[0024] Based on the above technical solution, preferably, step S4 includes a final forging upper die and a final forging lower die for performing final forging, wherein the final forging lower die includes a first lower module and a second lower module arranged on the left and right sides;

[0025] The first lower module and the second lower module have a second cavity on their mating side. After the two modules are tightly fitted together, they clamp the already formed shaft and disc parts to fix the workpiece. The shaft cavity is vertically set in the second cavity.

[0026] The bottom surface of the final forging die is provided with a third cavity that is consistent with the shape of the tie rod arm of the final forging, which is used to accommodate and correct the formed tie rod arm;

[0027] The surface of the final forging upper die is provided with a second forging upper cavity, and the surface of the final forging lower die is provided with a second forging lower cavity. The second forging upper cavity and the second forging lower cavity cooperate with each other to complete the final forging of the steering arm and its lug.

[0028] Furthermore, preferably, a flash groove is provided on the outer side of both the second forging upper cavity and the second forging lower cavity.

[0029] The present invention has the following advantages over the prior art:

[0030] (1) The integral steering knuckle forming process with tie rod arm and steering arm disclosed in this invention forms the shaft part, disc part, first straight arm and second straight arm by compound extrusion forming. The first straight arm is formed into tie rod arm and its corresponding ear by the downward pressure of the upper die in horizontal pre-forging. At the same time, the second straight arm is extruded into the pre-designed orientation by the downward pressure of the upper die, and the corresponding blank of the steering arm is further separated. After changing the orientation of the workpiece, the steering arm and its ear are formed by subsequent vertical final forging. During the extrusion process of horizontal pre-forging, the upper die will generate large compressive stress at the contact point with the root of the steering arm blank. In the prior art, the reason why root cracks may occur when "the straight arm is formed first and then bent" is because large tensile stress will be generated near the surface of the metal on the outside of the bent part during bending. This is the reason why this invention avoids the root cause of cracks by adjusting the process and avoids the hidden danger of large tensile stress generated by bending. The mechanical performance of the steering knuckle during service will also be more reliable.

[0031] (2) The present invention can avoid the large-area flash between the two ears and two arms in the steering knuckle forming process in the prior art through the new forming process design, ensuring high material utilization. In addition, both the pre-forging and final forging adopt semi-closed forging, which can achieve near-net-shape forming effect. It has the advantages of energy saving, shortening the product manufacturing cycle and reducing production costs. It can also obtain a reasonable metal flow distribution, improve the load-bearing capacity of the parts, avoid additional connection structures, reduce the weight of the parts, and improve the safety, reliability and service life of the products. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the integral steering knuckle forming process with tie rod arm and steering arm disclosed in this invention.

[0034] Figure 2 This is a schematic diagram of the state during the forming process of the steering knuckle disclosed in this invention;

[0035] Figure 3 This is a schematic diagram of the structure of the pre-forging upper die and the pre-forging lower die disclosed in this invention;

[0036] Figure 4 This is a schematic diagram of the structure of the pre-forging upper die disclosed in this invention;

[0037] Figure 5This is a schematic diagram showing the state of the pre-forging part formed by the pre-forging upper die and the pre-forging lower die disclosed in this invention;

[0038] Figure 6 This is a schematic diagram showing the state of the final forging part formed by the final forging upper die and the final forging lower die disclosed in this invention.

[0039] Figure 7 This is a schematic diagram of the structure of the first lower module, the second lower module, and the final forging upper die disclosed in this invention.

[0040] Figure 8 Schematic diagram of bending stress deformation and compressive stress deformation;

[0041] Figure label:

[0042] 1. Billet; 11. Disc section; 12. Shaft section; 13. First straight arm; 14. Second straight arm;

[0043] 2. Pre-forged part; 21. Tie rod arm; 22. Steering arm blank; 21a. Ear corresponding to the tie rod arm; 31a. Ear corresponding to the steering arm;

[0044] 3. Final forging; 31. Steering arm;

[0045] 4. Pre-forging upper die; 5. Pre-forging lower die; 41. First upper module; 42. Second upper module; 411. First upper cavity; 51. First lower cavity; 412. Nitrogen spring; 421. First forging upper cavity; 52. First forging lower cavity; 422. Insert; 53. First cavity;

[0046] 6. Final forging upper die; 7. Final forging lower die; 71. First lower die; 72. Second lower die; 73. Second cavity; 61. Third cavity; 62. Second forging upper cavity; 74. Second forging lower cavity. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] like Figure 1 As shown, combined with Figure 2 This invention discloses a forming process for an integral steering knuckle with tie rod arm and steering arm, including the following steps:

[0049] S1. Heat the billet 1 to the forging temperature, lay it horizontally, and flatten it radially by free forging. This is to flatten the billet 1 to make it easier for subsequent forging.

[0050] When heating billet 1, a medium-frequency induction furnace can be used to heat it at a temperature of 1200℃ to 1240℃, which facilitates flattening.

[0051] During billet preparation, the billet 1 is flattened and formed into a rectangular prism. The length and width of the billet are 6-10 mm smaller than the projected outer contours of the two ears and the disc 11 of the final forging 3.

[0052] S2. The flattened blank is placed into the extrusion cavity for compound extrusion to form the disc portion 11 and the shaft portion 12, and the first straight arm 13 and the second straight arm 14 are extruded. The first straight arm 13 and the second straight arm 14 are located on both sides of the disc portion 11 away from the shaft portion 12. The first straight arm 13 and the second straight arm 14 are arranged parallel to each other at intervals. The first straight arm 13 serves as the blank for forming the tie rod arm and its lug, and the second straight arm 14 serves as the blank for forming the steering arm and its lug. It is worth noting that the lug 21a of the tie rod arm and the lug 31a of the steering arm are both connected to the disc portion 11.

[0053] In the above steps, during the material distribution operation of the first straight arm 13 and the second straight arm 14 in the compound extrusion, the volume of the first straight arm 13 and the second straight arm 14 is 5% to 10% larger than the actual volume of the corresponding ears and arms of the final forging 3. The width of the first straight arm 13 and the second straight arm 14 is 100% to 110% of the maximum width of the corresponding ears of the final forging 3, and the thickness of the first straight arm 13 and the second straight arm 14 is 90% to 100% of the maximum thickness of the corresponding ears of the final forging 3.

[0054] In actual production, after determining the volume, width, and thickness of the first straight arm 13 and the second straight arm 14 according to the above requirements, the length of the entire billet can be calculated. That is, the lengths of the first straight arm 13 and the second straight arm 14 are adaptive to the above parameter settings. With this setting, the thickness can ensure that the first straight arm 13 and the second straight arm 14 can be smoothly placed into the mold, and the volume margin can ensure that the second straight arm 14 is compressed during pre-forging. At that time, a large compressive stress will be generated inside the billet, preventing the root of the second straight arm 14 from cracking. The length and width margins together constitute the volume margin, which allows the corresponding billet 22 of the steering arm to be better filled during pre-forging and final forging, and its stress and the generated flash will be more uniform.

[0055] S3. The blank formed in step S2 is placed horizontally into a semi-closed pre-forging mold. The first straight arm 13 is formed into a tie rod arm 21 and its ear 21a by pressing down with the upper mold. At the same time, the second straight arm 14 is squeezed to further separate the steering arm blank 22.

[0056] The billet after compound extrusion has a disc portion 11, a shaft portion 12, a first straight arm 13 and a second straight arm 14, wherein the disc portion 11 and the shaft portion 12 are formed into the shape required by the final forging 3 in the compound extrusion, and the first straight arm 13 is pre-forged into a tie rod arm and its ear portion 21a into the shape required by the final forging 3.

[0057] Specifically, refer to the appendix Figure 3-5 As shown, the semi-closed pre-forging mold used in step S2 includes a pre-forging upper mold 4 and a pre-forging lower mold 5. The pre-forging upper mold 4 includes a first upper module 41 and a second upper module 42 arranged on the left and right sides.

[0058] The surface of the first upper module 41 is provided with a first upper cavity 411, and the surface of the pre-forging lower die 5 is provided with a first lower cavity 51 that mates with the first upper cavity 411. The first upper cavity 411 and the first lower cavity 51 are used to press down the already formed shaft portion 12 and disc portion 11. Since the shaft portion 12 and disc portion 11 have already been formed into the shape required by the final forging 3 in the compound extrusion process, it is only necessary to press down the disc portion 11 and shaft portion 12 during the pre-forging process. The billet after compound extrusion is placed in the first lower cavity 51 of the pre-forging lower die 5, and the billet can be pressed and positioned by the cooperation of the first upper module 41 and the pre-forging lower die 5.

[0059] In order to ensure that the first upper module 41 can first contact the pre-forging lower die 5 to effectively compress the billet, the first upper module 41 and the second upper module 42 share an upper die frame to apply the downward forging force.

[0060] In this embodiment, a nitrogen spring 412 connected to the upper mold frame is provided on the top surface of the first upper module 41. As such, in the initial state, due to the action of the nitrogen spring 412, the first upper module 41 is lower than the second upper module 42. When the upper mold frame drives the first upper module 41 and the second upper module 42 to press down towards the pre-forging lower mold 5 simultaneously, the first upper module 42 contacts the pre-forging lower mold first. After the first upper module 41 and the pre-forging lower mold 5 are completely closed and pressed together, the blank can be fixed in the first upper cavity 411 and the first lower cavity 51, avoiding the blank from moving or flipping. During the continuous pressing process, the nitrogen spring 412 can apply a strong clamping force to the blank, providing conditions for the second module 42 to be formed.

[0061] In this embodiment, the clamping force provided by the nitrogen spring 412 must exceed the maximum extrusion deformation force by 5% to 10%. This is to prevent the billet from not moving on the pre-forging die during the pre-forging and extrusion process, thus ensuring the accuracy of pre-forging and extrusion.

[0062] The second upper module 42 has a first forging upper cavity 421 on its surface, and the pre-forging lower die 5 has a first forging lower cavity 52 on its surface. The first forging upper cavity 421 and the first forging lower cavity 52 cooperate to complete the final forging of the tie rod arm 21 and the ear 21a. That is, the first forging upper cavity 421 and the first forging lower cavity 52 cooperate to forge, so that the tie rod arm 21 formed by the first straight arm 13 is the shape required by the final forging 3. After the tie rod arm 21 is formed, it is not necessary to perform final forging of the tie rod arm 21 in the subsequent final forging process, which can save processes and improve forming efficiency.

[0063] In the above embodiment, a flash groove is provided on the outer side of both the first forging upper cavity 421 and the first forging lower cavity 52. ​​This design allows the tie rod arm 21 to be formed with only a small amount of flash, thereby improving material utilization.

[0064] An extrusion structure is provided between the second upper module 42 and the pre-forging lower die 5. The extrusion structure is used to extrude the second straight arm 14 to further separate the blank 22 required for the subsequent forging of the steering arm. This step replaces the steering arm forming achieved by bending process in the prior art.

[0065] During the pressing process, the second upper module 42 not only forms the tie rod arm 21, but also, through the extrusion structure between the second upper module 42 and the pre-forging lower die 5, extrudes the blank corresponding to the steering arm, i.e., the second straight arm 14, towards the pre-designed orientation. The extrusion structure generates significant compressive stress at its contact point with the root of the steering arm blank 22. (Refer to the attached diagram.) Figure 8 As shown. In the case of direct bending forming, large tensile stress will be generated near the surface of the metal on the outer side of the bending part during bending. Large tensile stress will cause root cracking. However, the extrusion structure in this embodiment generates large compressive stress at the part in contact with the root of the steering arm blank 22, which can avoid or reduce the occurrence of cracks and avoid the hidden danger of large tensile stress generated by bending. It also makes the mechanical performance of the one-piece steering knuckle more reliable during service.

[0066] In order to extrude the steering arm blank 22, this embodiment shows a preferred embodiment of the extrusion structure. Specifically, the extrusion structure includes an insert 422 disposed on the second upper module 42 and a first cavity 53 disposed on the pre-forging lower die 5.

[0067] The insert 422 is a long, straight protrusion. The thickness of the insert is the same as the thickness of the second straight arm 14. The width is 65% to 85% of the length of the second straight arm 14. The height must be such that when the second upper module 42 and the pre-forging lower die 5 are fully closed, the second straight arm 14 is squeezed downward by 75% to 85% of its volume. The left end face of the insert 422 is aligned with the top of the blank. The insert 422 is located directly above the blank.

[0068] The depth of the first cavity 53 is approximately 80% to 100% of the length of the steering arm of the final forging 3, the thickness of the first cavity 53 is consistent with the thickness of the second straight arm 14, and the width is compatible with the width 422 of the insert.

[0069] The left end face of insert 422 is aligned with the top of the second straight arm 14. Its width ensures that insert 422 can correctly act on the second straight arm 14 corresponding to the steering arm. Insert 422 is pressed down together with the second upper module 42, and the second straight arm 14 is squeezed into the first cavity 53. The depth, thickness, and width of the first cavity 53 are designed to ensure that its volume is smaller than the volume of the extruded blank, thus causing the blank to flow back. Furthermore, as mentioned above, the second straight arm 14 itself has allowance in its length and width. Both aspects ensure that the second straight arm 14 is compressed. During filling, this portion of the blank also generates high compressive stress internally, especially in the bending area, thereby preventing tearing caused by the bending process.

[0070] The area corresponding to the gap between the steering arm and the disc 11 in the final forging should be set as a solid with an inclination angle of at least 1° to 2° to the vertical direction, rather than a cavity. In this way, as the upper die is pressed down further, the tie rod arm 21 is forged and formed on the one hand, and the steering arm blank 22 is squeezed in a specified direction by means of the protrusion of the upper die, in preparation for the final forging of the steering arm.

[0071] Depending on the actual bending angle of the steering arm and its draft angle (or cone angle), a draft angle of 1°~2° is set on the left end face of the insert, and a certain inclination angle 'a' is set on the right end face of the insert. The inclination angle is set as 'a', and the value of 'a' ranges from (90°-b+c)+3°~5°, where b represents the bending angle of the steering arm and c represents the draft angle or cone angle. The (90°-b+c) is for the draft angle and also to ensure that the angle between the axis of the extruded steering arm blank and the axis of the ear blank is close to that of the final forging. The additional 3°~5° is to reserve a certain space between the steering arm blank and the disc to prepare for the next step of final forging the steering arm. Otherwise, the two modules of the final forging die will be difficult to close, and even if they do close, the steering arm blank will deform and warp upwards, interfering with the final forging.

[0072] In this example, the steering arm is bent at a right angle and has a draft angle of 2°. Taking a margin of 3°, the slope angle should be set to 5°.

[0073] In step S3 above, the blank extruded from the second straight arm 14 is the blank corresponding to the steering arm. The steering arm blank 22 and its ear blank 31a are bent at an angle. The ear blank is connected to the disc. The entire step S3 is to achieve the shape of the steering arm blank 22 through the extrusion process. The extrusion process generates large compressive stress at the connection between the steering arm blank 22 and the ear blank, especially at the bending part, avoiding the tensile stress caused by traditional bending, and thus solving the problem of tearing caused by the bending process.

[0074] S4. Change the orientation of the workpiece and place the blank formed in step S3 into the semi-closed final forging mold to form the steering arm 31 shape required by the final forging 3, thus completing the final forging of the steering knuckle.

[0075] In step S4, refer to the appendix Figure 6 and 7 As shown, the semi-closed final forging die includes an upper final forging die 6 and a lower final forging die 7. The lower final forging die 7 includes a first lower module 71 and a second lower module 72 arranged on the left and right sides.

[0076] The first lower module 71 and the second lower module 72 have a second cavity 73 on their mating surfaces, which is used to clamp the formed shaft portion 12 and disc portion 11 to fix the workpiece. The shaft portion cavity 12 is vertically arranged in the lower second cavity 73. In specific implementation, the blank from step S3 is placed vertically, with the tie rod arm 21 vertically upward and the corresponding shaft portion 12 vertically downward. The first lower module 71 and the second lower module 72 press the disc portion 11 and the shaft portion 12 through their second cavities 73. At this time, the steering arm blank 22 is in a state that is approximately parallel to the disc portion 11. In order to clamp the blank, the first lower module 71 and the second lower module 72 can apply a clamping force in the left and right directions to the final forging die 7 to ensure that the blank in the final forging die 7 does not shift.

[0077] The bottom surface of the final forging die 6 is provided with a third cavity 61 that is consistent with the shape of the tie rod arm of the final forging. During the pressing process of the final forging die 6, the third cavity 61 can accommodate and correct the already formed tie rod arm 21 without performing secondary forging on this arm.

[0078] The upper forging die 6 has a second forging upper cavity 62 on its surface, and the lower forging die 7 has a second forging lower cavity on its surface. The second forging upper cavity 62 and the second forging lower cavity 74 cooperate with each other to complete the final forging of the steering arm. During the closing process of the upper forging die 6 and the lower forging die 7, the steering arm blank 22 is forged through the second forging upper cavity 62 and the second forging lower cavity 74 to form the final steering arm that meets the design requirements. The arm portion and the ear portion 31a in the steering arm 31 are the shapes required for the final forging.

[0079] A flash groove is provided on the outer side of both the upper forging cavity 62 and the lower forging cavity 74, so that only a small amount of flash occurs during the forming of the steering arm, thereby improving material utilization.

[0080] In summary, during the process design, the lugs and arms on both sides of the workpiece are first considered as derived from two branches. This simplifies the integral steering knuckle to three parts in the blanking stage: the shaft 12, the disc 11, and the two straight arms. The shape is relatively regular and easy to form. Then, through a two-step forging process of "pre-forging (forming and material distribution) - final forging (final forming)," the forging is completed using a horizontal or vertical workpiece, a mold with a specific structure, and matching process parameters. The resulting steering arm has more reliable mechanical properties than that obtained by bending. After forging, the final forged part 3 is machined according to actual needs to obtain the final product.

[0081] In addition, the present invention avoids the large-area flash between the two ears and two arms that occurs during the forming process of the steering knuckle in the prior art through a new forming process design, ensuring high material utilization. In addition, both the pre-forging and final forging adopt semi-closed forging, which can ultimately achieve a near-net-shape forming effect. It has the advantages of energy saving, shortening the product manufacturing cycle, and reducing production costs. It can also obtain a reasonable metal flow distribution, improve the load-bearing capacity of the parts, avoid additional connection structures, reduce the weight of the parts, and improve the safety, reliability and service life of the products.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A one-piece steering knuckle forming process with tie rod arms and steering arms, characterized by, The method comprises the following steps: S1, heating the blank to a forging temperature, laying horizontally, and radially flattening by free forging; S2, putting the flattened blank into an extrusion cavity for compound extrusion to form a disc part and a shaft part, and extruding a first straight arm and a second straight arm; S3, laying the blank formed in step S2 horizontally into a semi-closed pre-forging cavity, and pressing down the upper die to form the first straight arm into a pull rod arm and its ear part, while the second straight arm is extruded to further separate the steering arm blank; S4, changing the direction of the workpiece, and standing the blank formed in step S3 into a semi-closed finish forging cavity to form the required shape of the steering arm of the finish forging piece, and completing the final forging of the steering knuckle; In step S2, the disc part and the shaft part are formed into the required shape of the finish forging piece in the compound extrusion, and in step S3, the pull rod arm and its ear part formed by pre-forging of the first straight arm are the required shape of the finish forging piece; In step S3, a pre-forging upper die and a pre-forging lower die for pre-forging are included, the pre-forging upper die comprises a first upper die block and a second upper die block arranged on the left and right sides; The surface of the first upper die block is provided with a first upper cavity, and the surface of the pre-forging lower die is provided with a first lower cavity matched with the first upper cavity, the first upper cavity and the first lower cavity are used to press the formed shaft part and disc part, and the top surface of the first upper die block is provided with a nitrogen gas spring connected with the upper die frame; The surface of the second upper die block is provided with a first forging upper cavity, and the surface of the pre-forging lower die is provided with a first forging lower cavity, the first forging upper cavity and the first forging lower cavity are matched with each other to complete the final forging of the pull rod arm and its ear part; An extrusion structure is arranged between the second upper die block and the pre-forging lower die, and the extrusion structure is used to extrude the second straight arm to further separate the blank corresponding to the steering arm; The extrusion structure comprises an insert arranged on the second upper die block and a first cavity arranged on the pre-forging lower die; The thickness of the insert is consistent with the thickness of the second straight arm, the width is 65% to 85% of the length of the second straight arm, and the height must make the blank be extruded into 75% to 85% of the volume when the second upper die block and the pre-forging lower die are completely closed, the left end surface of the insert is aligned with the top end of the second straight arm, and the insert is located directly above the second straight arm; The depth of the first cavity is equivalent to 80% to 100% of the length of the steering arm of the finish forging piece, the thickness of the first cavity is consistent with the thickness of the second straight arm, and the width is adapted to the width of the insert.

2. The one-piece steering knuckle with drag link arm and steering arm forming process of claim 1 wherein: In the blank separation operation of the first straight arm and the second straight arm in the compound extrusion, the volume of the first straight arm and the second straight arm is 5% to 10% more than the actual volume of the corresponding ear part and arm part of the finish forging piece, the width of the first straight arm and the second straight arm is 100% to 110% of the maximum width of the corresponding ear part of the finish forging piece, and the thickness of the first straight arm and the second straight arm is 90% to 100% of the maximum thickness of the corresponding ear part of the finish forging piece.

3. The one-piece steering knuckle with spindie arm and steering arm forming process of claim 1 wherein: The pressing force provided by the nitrogen gas spring must be 5% to 10% higher than the maximum extrusion deformation force.

4. The one-piece steering knuckle with spindie arm and steering arm forming process of claim 1 wherein: A circle of flash groove is arranged on the outside of the first forging upper cavity and the first forging lower cavity.

5. The one-piece steering knuckle with spindie and steering arm forming process of claim 1 wherein: The left end surface of the insert is provided with a draft angle of 1°-2°, and the right end surface of the insert is provided with a certain inclination angle a, the value range of a is (90°-b+c)+3°-5°, wherein b represents the bending angle of the steering arm, and c represents the draft angle or the taper angle.

6. The one-piece steering knuckle with spindie arm and steering arm forming process of claim 1 wherein: In step S4, a finish-forging upper die and a finish-forging lower die for performing finish-forging forming are included, and the finish-forging lower die includes a first lower die block and a second lower die block arranged left and right; One surface of the first lower die block and the second lower die block in cooperation is provided with a second cavity, after the two blocks are closely attached, the shaft part and the disc part which have been formed are clamped, the workpiece is fixed, and the shaft part cavity is vertically arranged in the second cavity; The bottom surface of the finish-forging upper die is provided with a third cavity which is consistent with the shape of the pull rod arm of the finish-forging part, for accommodating and correcting the formed pull rod arm; The surface of the finish-forging upper die is provided with a second forging upper cavity, and the surface of the finish-forging lower die is provided with a second forging lower cavity, the second forging upper cavity and the second forging lower cavity are mutually matched for completing the final forging of the steering arm and the ear part thereof.

7. The one-piece steering knuckle with drag link arm and steering arm forming process of claim 6 wherein: A circle of flash grooves are arranged outside the second forging upper cavity and the second forging lower cavity.

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