Full stream line near net shape front axle forging

Abstract

This invention relates to the field of vehicle component technology, and in particular to a fully streamlined near-net-shape front axle forging. The fully streamlined near-net-shape front axle forging includes a kingpin, a bend arm, leaf spring seats, and an I-beam. Leaf spring seats are connected to both ends of the I-beam, and the two leaf spring seats are connected to the kingpin via the bend arm. The leaf spring seats have a fully streamlined near-net-shape structure, while the I-beam has an asymmetrical structure. The fully streamlined near-net-shape front axle forging is integrally forged from non-quenched and tempered steel using precision forging. After forging, controlled temperature cooling results in uniform and stable surface hardness, high strength, and minimal deformation. The fully streamlined structure of the front axle forging reduces the size of the leaf spring seats and the weight of the front axle forging. The near-net-shape structure facilitates shorter forging, inspection, and machining processes, improving processing efficiency. Simultaneously, the asymmetrical design of the I-beam contributes to the lightweighting of the front axle forging.

Description

Technical Field

[0001] This invention relates to the field of vehicle parts technology, and in particular to a fully streamlined near-net-shape front axle forging. Background Technology

[0002] As a crucial safety component of a vehicle, the front axle's strength and rigidity directly affect the vehicle's safety and stability during driving. The main structure of the front axle includes the kingpin, hinged arms, leaf spring seats, and I-beams, with symmetrical structures at both ends. The kingpins are located at both ends of the front axle and connect to the leaf spring seats via the hinged arms; the I-beams are located in the middle of the front axle, connecting the leaf spring seats at both ends.

[0003] Currently, traditional automotive front axle forgings use quenched and tempered steel. After quenching and tempering, the surface hardness of the forgings is uneven and unstable, affecting the strength and rigidity of the front axle. The workpieces suffer from severe bending and torsion deformation after heat treatment, requiring cold straightening to meet machining requirements. Furthermore, the upper and lower planes, or the upper plane, of the front axle leaf spring seats need to be machined to meet the dimensional and positional tolerances and precision requirements of the finished product. The forging and machining processes are lengthy and inefficient. Machining disrupts the forging flow lines of the front axle, reducing its strength and rigidity. The forging inspection process is lengthy, requiring two or more installations and datum changes for inspection, resulting in low inspection efficiency and insufficient accuracy. Moreover, the inspection datum is not consistent with the machining positioning datum, leading to low machining quality and efficiency. While the I-beam section has a fully symmetrical structure (either vertically or horizontally) and a relatively high and thick web, which meets the strength and rigidity requirements of the front axle, the front axle is still relatively heavy, hindering its weight reduction. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a fully streamlined near-net-shape front axle forging to solve the problems of uneven and unstable surface hardness of the front axle, low forging, inspection and machining efficiency, unstable product quality, heavy forgings and finished products, and poor appearance and marketability in the prior art.

[0005] To achieve the above and other related objectives, the present invention provides a fully streamlined near-net-shape front axle forging. The fully streamlined near-net-shape front axle forging is integrally forged from non-quenched and tempered steel material and includes a kingpin, a bent arm, a leaf spring seat, and an I-beam. The two ends of the I-beam are respectively connected to the leaf spring seats, and the two leaf spring seats are respectively connected to the kingpin through the bent arm. The leaf spring seat is a fully streamlined near-net-shape structure, and the I-beam is an asymmetrical structure.

[0006] The fully streamlined near-net-shape front axle forging of the present invention has at least the following beneficial effects: the fully streamlined near-net-shape front axle forging is integrally forged from non-quenched and tempered steel material through precision forging; after forging, the surface hardness is uniform and stable, with high strength and small deformation due to controlled temperature cooling; the front axle forging has a fully streamlined structure, reducing the length, width, and height dimensions of the leaf spring seat and reducing the weight of the front axle forging; it only requires one installation, and inspection can be completed in two states, with or without pins, without changing the inspection datum, shortening the forging inspection process, improving the efficiency and accuracy of forging inspection, and simultaneously unifying the inspection datum with the machining positioning datum, improving the quality and efficiency of machining; the near-net-shape structure is conducive to shortening the machining process and improving machining efficiency, while the I-beam adopts an asymmetrical structural design, achieving lightweighting of the front axle forging.

[0007] Optionally, the surface hardness difference of the fully streamlined near-net-shape front shaft forging is less than or equal to HB20.

[0008] Optionally, both the upper and lower planes of the leaf spring seat are heat-corrected planes. Temperature-controlled cooling after forging results in minimal deformation, eliminating the need for cold straightening and machining to meet the dimensional and positional tolerances and precision requirements of the finished front axle.

[0009] Optionally, the upper surface of the leaf spring seat is a smooth and flat surface, and the upper surface has a bright edge band; wherein the bright edge band accounts for more than 95% of the cut edge area of ​​the upper surface, and the upper surface shows no magnetic traces after thermal correction and magnetic particle inspection.

[0010] Optionally, the connection points between the upper plane and the curved arm and the I-beam are all smoothly transitioned by a large rounded corner structure. The large rounded corner structure includes a concave first rounded corner and a convex second rounded corner. One end of the second rounded corner is connected to the upper plane, and the other end of the second rounded corner is connected to the curved arm and the I-beam through the first rounded corner. This large rounded corner structure avoids stress concentration during the front axle's stress process, improving the front axle's strength; it also facilitates material flow and filling, extending the mold's lifespan.

[0011] Optionally, the radius of the first fillet is R. 11 The R 11 The range is 60–180 mm; the radius of the second fillet is r. 11 The r 11 The range is 3 to 6 mm.

[0012] Optionally, both the edges in the width direction of the upper plane and the edges in the width direction of the lower plane are forged with a convex third fillet.

[0013] Optionally, the radius of the third fillet is r. 12 The r 12The range is 3 to 6 mm.

[0014] Optionally, the flatness of the upper plane and the flatness of the lower plane are both less than or equal to 0.8 mm; the flatness between the upper planes of the two leaf spring seats is less than or equal to 1.5 mm; the parallelism between the upper plane and the lower plane is less than or equal to 1.3 mm; and the symmetry of the centers of the two leaf spring seats with respect to the line connecting the centers of the two kingpins is less than or equal to 1.5 mm.

[0015] Optionally, the I-beam includes a web, an upper flange, and a lower flange. The top and bottom of the web are connected to the upper flange and the lower flange, respectively. The upper flange includes an upper wide wing and an upper narrow wing, the width of which is greater than or equal to the width of which is which. The lower flange includes a lower wide wing and a lower narrow wing, the width of which is greater than the width of which is which. The upper wide wing and the lower narrow wing are located on a first side of the web, and the upper narrow wing and the lower wide wing are located on a second side of the web. The first side of the web faces the reversing direction of the vehicle, and the second side of the web faces the forward direction of the vehicle. The width direction of the upper wide wing, the upper narrow wing, the lower wide wing, and the lower narrow wing is the driving direction of the vehicle.

[0016] Optionally, the width of the upper wide wing is smaller than the width of the lower wide wing; the width of the upper narrow wing is less than or equal to the width of the lower narrow wing. Attached Figure Description

[0017] Figure 1 The diagram shown is a structural schematic of an embodiment of the streamlined near-net-shape front shaft forging of the present invention.

[0018] Figure 2 Displayed as Figure 1 A schematic diagram of the cross-section of a steel leaf spring seat;

[0019] Figure 3 Displayed as Figure 1 A schematic diagram showing the dimensional accuracy of the leaf spring seat in the near-net-shape front axle forging with full streamline;

[0020] Figure 4-1 Displayed as Figure 1 A cross-sectional view of the leaf spring seat of the front axle forging with full streamline near-net-shape forming.

[0021] Figure 4-2 Displayed as Figure 1 Streamline diagram of the leaf spring seat of the front axle forging with full streamline near-net-shape forming;

[0022] Figure 4-3 Displayed as Figure 1 A cross-sectional view of the leaf spring seat of the near-net-shape front axle forging during the straightening process;

[0023] Figure 4-4 Displayed as Figure 1 A cross-sectional view of the leaf spring seat of the front shaft forging in the final forging process during the full-stream near-net-shape forming process;

[0024] Figure 5-1 Shown is a cross-sectional view of a leaf spring seat as a conventional first front axle forging finished product;

[0025] Figure 5-2 Shown as a streamline diagram of a conventional first front axle forging finished steel leaf spring seat;

[0026] Figure 5-3 Shown is a cross-sectional view of the leaf spring seat of the conventional first front axle forging during the straightening process;

[0027] Figure 5-4 Shown is a cross-sectional view of the leaf spring seat of the traditional first front axle forging in the final forging process;

[0028] Figure 6-1 Shown is a cross-sectional view of a leaf spring seat as a conventional second front axle forging;

[0029] Figure 6-2 Shown as a streamline diagram of a conventional second front axle forged leaf spring seat;

[0030] Figure 6-3 Shown is a cross-sectional view of a leaf spring seat in the straightening process of a conventional second front axle forging;

[0031] Figure 6-4 Shown is a cross-sectional view of the leaf spring seat of a conventional second front axle forging in the final forging process;

[0032] Figure 7 Displayed as Figure 1 Front view of a near-net-shape forging structure with full streamline;

[0033] Figure 8 Displayed as Figure 7 Cross-sectional view of section A1-A1;

[0034] Figure 9 The diagram shows a cross-sectional view of the I-beam portion, representing another embodiment of a fully streamlined near-net-shape forging structure.

[0035] Part Number Explanation

[0036] 100 - I-shaped section; 101 - Web plate; 102 - Upper flange; 1021 - Upper wide flange; 1022 - Upper narrow flange; 103 - Lower flange; 1031 - Lower wide flange; 1032 - Lower narrow flange; 200 - Leaf spring seat; 201 - Upper plane; 202 - Lower plane; 203 - Streamlined anatomical surface; 204 - Slit edge bright band; 300 - Bent arm; 400 - Kingpin. Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show components relevant to the present invention and are not drawn according to the actual number, shape, and size of components in implementation. In actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the component layout may be more complex. The structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives of the present invention, should still fall within the scope of the technical content disclosed in the present invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0039] Before describing the embodiments of the present invention in detail, the application environment of the present invention will be described first. The technology of the present invention is mainly applied to automotive front axles, especially to fully streamlined near-net-shape front axle forgings. The present invention solves the problems of uneven and unstable hardness after traditional front axle quenching and tempering heat treatment, complex processing procedures, low production efficiency of forging, inspection and machining, heavy product weight and poor appearance. Therefore, the fully streamlined near-net-shape front axle forgings provided by this application have uniform and stable surface hardness and high strength. They do not require cold straightening and subsequent machining, and can meet the form and position tolerances and precision requirements of the finished product, improve the appearance of the product, achieve lightweighting of the finished product, ensure product quality and improve production efficiency.

[0040] See Figure 1In one embodiment, this application provides a fully streamlined near-net-shape front axle forging. This forging is integrally forged from non-quenched and tempered steel, specifically using a near-net-shape forging process. The fully streamlined near-net-shape front axle forging includes a kingpin 400, a bent arm 300, a leaf spring seat 200, and an I-beam 100. Leaf spring seats 200 are connected to both ends of the I-beam 100, and the two leaf spring seats 200 are connected to the kingpin 400 via the bent arm 300. The fully streamlined near-net-shape front axle forging has a symmetrical structure at both ends, with the I-beam 100 located in the middle. The kingpin 400, bent arm 300, and leaf spring seat 200 are all symmetrically distributed around the center of the I-beam 100. The leaf spring seat has a fully streamlined near-net-shape structure, while the I-beam has an asymmetrical structure.

[0041] Optionally, the surface hardness difference of the fully streamlined near-net-shape front shaft forging is less than or equal to HB20.

[0042] The aforementioned streamlined near-net-shape front axle forging is integrally forged from non-quenched and tempered steel, which improves the strength of the leaf spring seat, shortens the machining process, increases processing efficiency, and maximizes material utilization. Specifically, the front axle forging uses high-strength non-quenched and tempered steel, resulting in uniform and stable surface hardness and high strength. The streamlined forging structure meets the strength and stiffness requirements of the front axle while reducing the length, width, and height of the leaf spring seat, thus reducing the weight of both the forging and the finished product. Its near-net-shape forging structure minimizes workpiece deformation during controlled-temperature cooling after forging, eliminating the need for cold straightening and machining to meet the dimensional and positional tolerances and precision requirements of the finished front axle. Furthermore, it facilitates shorter forging and machining processes, improving overall processing efficiency.

[0043] See Figures 1 to 3 In one embodiment, the upper plane 201 and lower plane 202 of the leaf spring seat 200 are both heat-corrected planes. During heat correction, the good appearance of the front axle forging is maintained to the maximum extent, forming a fully streamlined, near-net-shape forging structure, improving the strength and rigidity of the front axle. Furthermore, the upper and lower planes of the leaf spring seat can meet the finished product's form and position tolerances and accuracy requirements without cold straightening or machining, shortening the forging and machining process and improving processing efficiency. Specifically, since the upper and lower planes of the leaf spring seat do not require machining, the inspection of the front axle forging and subsequent machining of other parts are based on the upper plane of the leaf spring seat. Inspection can be completed in only one installation state, using either a pin-attached or non-pin-attached configuration, without needing to change the inspection datum. This helps shorten the forging inspection process, improves the inspection efficiency and accuracy of the forging, and simultaneously unifies the forging inspection datum with the machining positioning datum, improving the quality and efficiency of machining.

[0044] Optionally, the upper surface 201 of the leaf spring seat 200 is a smooth and flat surface, and the upper surface 201 has a kerfed bright band 204; wherein the kerfed bright band 204 accounts for more than 95% of the kerfed area of ​​the upper surface, and no magnetic trace is shown after magnetic particle inspection after heat correction. It is understood that the production process of the fully streamlined near-net-shape front axle forging of this application includes a final forging process, a kerfing process, and a heat correction process, and the final forging process, the kerfing process, and the heat correction process are performed sequentially. The final forging process obtains the final forging, and the upper surface of the leaf spring seat of the final forging is kerfed in the kerfing process, and then corrected in the heat correction process after the kerfing is completed.

[0045] Optionally, the flatness of the upper plane 201 and the flatness of the lower plane 202 are both less than or equal to 0.8 mm.

[0046] Optionally, the flatness between the upper surfaces 201 of the two leaf spring seats 200 is less than or equal to 1.5 mm.

[0047] Optionally, the parallelism between the upper plane 201 and the lower plane 202 is less than or equal to 1.3 mm.

[0048] Optionally, the symmetry of the center of the two leaf spring seats 200 with respect to the line connecting the centers of the two kingpins 400 is less than or equal to 1.5 mm.

[0049] See Figure 1 , Figure 2 , Figures 4-1 to 4-4 In one embodiment, the connection points between the upper plane 201 and the curved arm 300 and the I-beam 100 are all smoothly transitioned by a large rounded corner structure. The large rounded corner structure includes a concave first rounded corner and a convex second rounded corner. One end of the second rounded corner is connected to the upper plane 201, and the other end of the second rounded corner is connected to the curved arm 300 and the I-beam 100 respectively through the first rounded corner. The large rounded corner structure, composed of the second and first rounded corners, improves the structure of the front axle forging, facilitates material flow and filling, and increases material utilization. Specifically, the first rounded corner is a concave large rounded corner, and the second rounded corner is a convex large rounded corner. This avoids stress concentration caused by step differences and small-radius concave arcs after machining, avoids sharp corners and burrs on the upper and lower plane edges after machining, prevents defects in the finished front axle, facilitates material flow and filling during the forging process, and extends die life.

[0050] Optionally, the radius of the first fillet is R. 11 R 11 The range can be 60 to 180 mm.

[0051] Optionally, the radius of the second fillet is r. 11 r 11 The range can be 3 to 6 mm.

[0052] Optionally, the corrected part (i.e., the cold-forged front axle) obtained from the front axle forging during the correction process has the same structural dimensions and precision as the leaf spring seat of the finished front axle forging, i.e., BC. 11 =b 11 HC 11 =h 11 LC 11 =l 11 DC 11 =d 11 .

[0053] Optionally, the front axle forging of this application is used to obtain the final forging BF in the final forging process. 11 With HF 11 The ratio is relatively small, and the leaf spring seat adopts a segmented draft structure, in which β 12 <β 11 This not only improves the filling properties of the forging but also ensures that the bright band on the cut edge accounts for more than 95% of the cut edge area after hot straightening, and no magnetic traces are detected by magnetic particle inspection. Furthermore, the second fillet radius r of the final forging... 11 A variable fillet radius means that the radius of the fillet is not always the same; it changes slightly from the beginning to the end of the fillet, gradually decreasing or increasing. This is achieved through the second fillet radius r of the final forging. 11 Compensation designs such as variable fillet radius enable thermally corrected LC... 11 =l 11 This creates a smooth structure with the second fillet and the large fillet of the first fillet, improving the strength and rigidity of the front axle.

[0054] The fully streamlined near-net-shape front axle forging described above helps to meet the strength and stiffness requirements of the front axle while reducing the length, width, and height dimensions of the leaf spring seat, thus reducing the weight of the front axle forging and the finished product.

[0055] See Figure 1 , Figure 2 , Figures 4-1 to 4-4 In one embodiment, the edges of the upper plane 201 in the width direction and the edges of the lower plane 202 in the width direction are both forged with a convex third rounded corner.

[0056] Optionally, the radius of the third fillet is r. 12 r 12 The range can be 3 to 6 mm.

[0057] The streamlined near-net-shape front axle forging described above has forged second and third fillets, which improves the marketability of the front axle appearance and saves the deburring process, thus improving the front axle processing efficiency.

[0058] See Figures 4-1 to 6-4To further demonstrate the characteristics of the fully streamlined near-net-shape front axle forging of this application, the fully streamlined near-net-shape front axle forging of this application is compared with the conventional first front axle forging and second front axle forging.

[0059] See Figures 5-1 to 5-4 The fully streamlined near-net-shape front axle forging of this application is compared with the traditional first front axle forging, specifically including comparison of finished products, comparison of corrected parts, and comparison of final forgings:

[0060] Comparing the finished products, the raw material of the first front axle forging is quenched and tempered steel, which has uneven and unstable hardness after heat treatment; the deformation after heat treatment is large, and cold straightening is required to meet the requirements of machining; the upper and lower surfaces of the leaf spring seat are both machined surfaces, and after machining, there are continuous and / or discontinuous irregular steps and small concave rounded corners at the connection between the upper surface of the leaf spring seat and the bent arm and I-beam, which affects the appearance and marketability of the finished product, and stress concentration is easily generated at this part during the front axle under stress, reducing the strength of the front axle; after machining, there are sharp corners and burrs on the upper and lower edges of the leaf spring seat, which need to be ground off, which is inefficient; machining destroys the forging flow lines of the upper and lower surfaces of the leaf spring seat, reducing the strength of the front axle; in order to meet the strength and rigidity of the front axle, the length, width and height of the leaf spring seat are large, resulting in a large finished product weight.

[0061] Comparing the calibration parts, the first front axle forging yields a calibration part after the calibration process. The upper and lower surfaces of the leaf spring seat in this calibration part are both draft angles of the final forging, requiring machining to meet the dimensional and positional tolerances and precision requirements of the finished product. Specifically, the draft angle α on the upper and lower surfaces of the leaf spring seat in the calibration part... 21 and β 21 Large, and machining allowance δ 21 and t 21 Larger, HC 21 =δ 21 +h 21 +t 21 Low processing efficiency and high processing cost; has a processing allowance δ 21 and draft angle β 21 The resulting steps, at the connection between the upper surface of the leaf spring seat and the bent arm and I-beam, have continuous and / or discontinuous irregular steps and small concave rounded corners, affecting the appearance and marketability of the finished product. Furthermore, stress concentration is easily generated at this location during the front axle's stress process, reducing the front axle's strength. Sharp corners and burrs exist on the edges of the upper and lower surfaces of the leaf spring seat after machining, affecting the product's appearance and requiring grinding removal, which is inefficient. The forging inspection process is lengthy, requiring two installations and two changes of inspection datum to complete the inspection, resulting in low inspection efficiency and insufficient accuracy. Moreover, the inspection datum is not consistent with the machining positioning datum, leading to low machining quality and efficiency.

[0062] Comparison of final forgings: The final forging and the corrected part have the same structural dimensions. LF21 =LC 21 BF 21 =BC 21 HF 21 =HC 21 ; Final forging BF 21 With HF 21 A large ratio indicates poor filling properties in the forging; large draft angles α are required on both the upper and lower surfaces of the leaf spring seat. 21 and β 21 Furthermore, the machining allowance is relatively large, requiring large-diameter billets for forging, resulting in low material utilization; the final forging has machining allowance and draft angle β. 21 The resulting step has a small-radius outward convex arc r. 21 Through the concave arc R 21 With concave arc R 22 The first end is connected, with an inward concave arc R 22 The second end connects to the bend arm and the I-beam, with a smaller outward convex arc r at the step. 21 and concave arc R 21 This increases the difficulty of forging, and the poor fluidity of the material makes it easy for the forging to be incompletely filled.

[0063] See Figures 6-1 to 6-4 The comparison between the fully streamlined near-net-shape front axle forging of this application and the traditional second front axle forging specifically includes a comparison of finished products, a comparison of corrected parts, and a comparison of the final forging:

[0064] Comparing the finished products, the raw material for the second front axle forging is quenched and tempered steel, which results in uneven and unstable hardness after heat treatment; the heat treatment deformation is large, requiring cold straightening to meet machining requirements; the upper surface of the leaf spring seat is a machined surface with a large machining allowance and low machining efficiency; the lower surface is a heat straightening surface, i.e., d 32 =DC 32 The upper surface has a machining allowance δ 31 The resulting steps, after machining, create continuous and / or discontinuous irregular steps and small concave rounded corners at the connection between the upper surface of the leaf spring seat and the I-beam and the curved arm. This affects the appearance and marketability of the finished product, and also easily causes stress concentration at this location during the front axle's stress process, reducing the strength of the front axle. Extrusion protrusions exist at the connection between the leaf spring seat and the curved arm and I-beam, affecting the appearance and increasing the weight of the front axle forging. Sharp burrs on the edges of the upper surface of the machined leaf spring seat affect the appearance and marketability of the finished product, requiring grinding removal and reducing efficiency. Machining disrupts the forging flow lines of the upper surface of the leaf spring seat, reducing the strength of the front axle. To meet the strength and rigidity requirements of the front axle, the length, width, and height dimensions of the leaf spring seat are relatively large, resulting in a large forging or finished product weight.

[0065] Comparing the calibration parts, although the upper and lower surfaces of the leaf spring seat of the calibration part are heat-calibrated planes, the width BC of the upper plane of the leaf spring seat of the calibration part is different. 31 The presence of abnormal protrusions and burrs on both sides, along with unevenness at the cut edges, necessitates a machining allowance on the upper surface of the leaf spring seat. Machining is required to meet the dimensional and positional tolerances and precision requirements of the finished product. The upper surface has a machining allowance δ. 31 The resulting steps can easily lead to continuous and / or discontinuous irregular steps and small concave fillets at the connection between the upper surface of the leaf spring seat and the bend arm and I-beam after machining, affecting the appearance and marketability. Furthermore, stress concentration is likely to occur at this location during the front axle's stress process, reducing the strength of the front axle. Extrusion protrusions exist at the connection between the leaf spring seat and the bend arm and I-beam, resulting in poor appearance and increased forging quality. The forging inspection process is lengthy, requiring three installations and two changes of inspection datum to complete the inspection, resulting in low inspection efficiency and insufficient inspection accuracy. Moreover, the inspection datum is not consistent with the machining positioning datum, leading to low machining quality and efficiency.

[0066] Comparison of final forgings: The upper and lower surfaces of the final forged leaf spring seat are both draft slopes; BF 31 With HF 31 The ratio is relatively large, the forging has poor filling properties, and a large draft angle α is required on both the upper and lower surfaces of the leaf spring seat. 31 and β 31 Furthermore, the large machining allowance necessitates the forging of large-diameter blanks, resulting in low raw material utilization; the final forging exhibits machining allowance and draft angle β. 31 The resulting step has a small-radius outward convex arc r. 31 and a smaller concave arc R 31 This increases the difficulty of forging, and the poor fluidity of the material makes it easy for the forging to be incompletely filled.

[0067] See Figures 4-1 to 6-4 The streamlined near-net-shape front axle forging of this application uses high-strength non-quenched and tempered steel. After forging, controlled-temperature cooling results in uniform and stable surface hardness, high strength, and minimal deformation. Precision forging can achieve the required form and position tolerances and precision of the finished front axle. In contrast, the first and second front axle forgings are made of quenched and tempered steel, resulting in uneven and unstable surface hardness after heat treatment and significant deformation. Only subsequent cold straightening and machining can achieve the required form and position tolerances and precision of the finished product. While ensuring the strength and rigidity of the front axle forging, the length, width, and height dimensions of the front axle forging in this application are minimized, meaning the cross-sectional and longitudinal areas of the front axle are minimized. The mass of the leaf spring seat portion of the front axle forging is reduced by 3%–7%, the billet diameter of the raw material is reduced, and the utilization rate of the raw material is increased by approximately 3%–7%. That is, the length l 11 <l 21 ≤l 31 Width b 11 <b31 =b 21 Height h 11 <h 31 =h 21 Thermal correction or machining depth d 11 <d 31 <d 21 The upper and lower planes of the leaf spring seat in this application are both heat-corrected planes, with over 95% of the cut edges showing a bright band, and no magnetic traces are detected by magnetic particle inspection. Temperature-controlled cooling results in minimal deformation, eliminating the need for cold straightening and machining to meet the finished product's dimensional and positional tolerances and precision requirements, thus achieving a fully streamlined forging structure. The connection between the upper plane and the curved arm and I-beam is a smooth, large-rounded structure formed by the second and first rounded corners, facilitating material flow and filling, and extending mold life. This shortens the forging inspection process, requiring only one installation and allowing inspection to be completed in both pin-inserted and pin-free states, without needing to change the inspection datum, thus improving the efficiency and precision of forging inspection. Simultaneously, it unifies the forging inspection datum and machining positioning datum, improving processing quality and efficiency. The leaf spring seat's width-direction edges have a third rounded corner, resulting in a better appearance and saving the deburring process, thus increasing efficiency. In contrast, the upper and lower planes, or the upper plane, of the leaf spring seats in the first and second front axle forgings require machining to meet the finished product's dimensional and positional tolerances and precision requirements. The following issues exist: After machining, the upper surface of the leaf spring seat has continuous and / or discontinuous irregular steps and small concave rounded corners at the connection between the I-beam and the curved arm. This affects the finished product's appearance and can easily cause stress concentration at this location during front axle loading, reducing the front axle's strength. Sharp burrs on the edges of the machined leaf spring seat also affect the finished product's appearance and require grinding removal, which is inefficient. Machining disrupts the forging flow lines on the upper surface of the leaf spring seat, reducing the front axle's strength. To meet the strength and rigidity requirements of the front axle, the length, width, and height dimensions of the leaf spring seats in the first and second front axle forgings are relatively large, resulting in a larger forging or finished product weight. Furthermore, the connection between the second front axle leaf spring seat and the curved arm and I-beam has extrusion protrusions, affecting the appearance and increasing the weight of the front axle forging. The forging inspection process is lengthy, requiring two or more installations and reference changes for inspection, resulting in low inspection efficiency and insufficient accuracy. Additionally, the inspection reference is not consistent with the machining positioning reference, leading to low machining quality and efficiency.

[0068] See Figures 4-1 to 6-4 The corrected part obtained from the near-net-shape streamlined front axle forging of this application during the correction process is compared with the corrected parts obtained from the first front axle forging and the second front axle forging during the correction process. In terms of structural dimensions, the length LC 11 <LC 21 ≤LC 31 Width BC 11 <BC 31 =BC 21 High HC11 <HC 31 <HC 21 Thermal correction depth DC 11 <DC 31 After the front axle forging undergoes hot straightening during the hot straightening process, the upper and lower planes of the leaf spring seat do not require machining to meet the form and position tolerances and precision requirements of the finished front axle, i.e., b. 11 =BC 11 h 11 =HC 11 , l 11 =LC 11 d 11 =DC 11 The innovative design of the forging with large, rounded corners and a smooth structure facilitates material flow and filling, extending mold life. It shortens the forging inspection process, requiring only one installation and allowing inspection in both pin-inserted and pinless states without changing the inspection datum, thus improving inspection efficiency and accuracy. Simultaneously, it unifies the inspection datum with the machining positioning datum, improving machining quality and efficiency. The near-net-shape forging structure further shortens the machining process and improves machining efficiency. The innovative asymmetrical I-beam design achieves lightweighting of the front axle forging. However, after hot straightening in the first front axle forging process, the upper and lower surfaces of the leaf spring seat are draft angles, requiring machining to meet the assembly and precision requirements of the finished front axle. After hot straightening in the second front axle forging process, the lower surface of the leaf spring seat becomes the hot straightening surface, i.e., DC. 31 =d 31 BC of the upper plane 31 The presence of abnormal protrusions and burrs on both sides, along with unevenness at the cut edges, necessitates machining of the upper surface of the leaf spring seat to meet the assembly and precision requirements of the finished product. The upper surfaces of the first and second front axle forgings have steps formed by machining allowances and draft angles. After machining, the connection between the upper surface of the leaf spring seat and the I-beam and the bend arm exhibits continuous and / or discontinuous irregular steps and small concave fillets, affecting the finished product's appearance and commercial viability. Furthermore, stress concentration is likely to occur at this location during front axle loading, reducing the front axle's strength. The edges of the machined leaf spring seat also have sharp burrs, further impacting the finished product's appearance and requiring further machining. Grinding and cleaning reduce efficiency; machining damages the forging flow lines of the leaf spring seats, reducing the strength of the front axle; to meet the strength and rigidity requirements of the front axle, the length, width, and height dimensions of the leaf spring seats in the first and second front axle forgings are relatively large, resulting in a larger forging or finished product weight; and the connection between the second front axle leaf spring seat and the bend arm and I-beam has extrusion protrusions, affecting the appearance and increasing the weight of the front axle forgings; the forging inspection process is lengthy, requiring two or more installations and changes in reference for inspection, resulting in low inspection efficiency and insufficient inspection accuracy, and the inspection reference is not consistent with the machining positioning reference, leading to low machining quality and efficiency.

[0069] See Figures 4-1 to 6-4 Compared with the final forgings obtained in the final forging process of the fully streamlined near-net-shape front axle forging of this application, the final forging of the same forging process of the first and second front axle forgings has the following structural dimensions: LF length 11 <LF 21 ≤LF 31 Width BF 11 <BF 31 <BF 21 ; HF height 11 <HF 31 <HF 21 Draft angle β 11 <β 31 <β 21 ;β 12 <β 11 ;α 11 <α 31 <α 21 The front axle forgings in this application undergo final forging followed by BF (Browser Forging). 11 With HF 11 The ratio is relatively small, and the leaf spring seat adopts a segmented draft structure, in which β 12 <β 11 This improved the filling properties of the forgings, meeting the requirement of no magnetic marks on the cut edges after hot straightening, while also reducing the size of the raw materials and increasing their utilization rate. Furthermore, the structural dimensions of the forgings in the first front axle final forging process are the same as those in the straightening process. 21 =LC 21 BF 21 =BC 21 HF 21 =HC 21 BF 21 With HF 21 A large ratio indicates poor filling properties in the forging, requiring large draft angles α on both the upper and lower surfaces of the leaf spring seat. 21 and β 21 Furthermore, it requires large-scale raw materials for forging, resulting in low material utilization. The BF (Burning Factor) of the final forging obtained from the second front axle final forging process... 31 With HF 31 The ratio is relatively large, the forging has poor filling properties, and a large draft angle α is required on both the upper and lower surfaces of the leaf spring seat. 31 and β 31 Furthermore, it requires larger raw material specifications, resulting in low material utilization. Additionally, the fully streamlined near-net-shape front shaft forging of this application, through the final forging process, utilizes the second fillet radius r of the final forging. 11 Compensation designs such as variable fillet radius enable thermally corrected LC... 11 =l 11This creates a smooth structure with a large rounded corner between the second and first rounded corners, improving the strength and rigidity of the front axle. The final forgings of both the first and second front axles have steps formed by machining allowances and draft angles, with a small-radius outward-convex arc r on the step. 21 / r 31 and a smaller concave arc R 21 / R 31 This increases the difficulty of forging, and the poor fluidity of the material makes it easy for the forging to be incompletely filled.

[0070] See Figure 1 , Figures 7 to 9 In some embodiments, the H-beam 100 includes a web 101, an upper flange 102, and a lower flange 103. The top and bottom of the web 101 are connected to the upper flange 102 and the lower flange 103, respectively. The upper flange 102 includes an upper wide wing 1021 and an upper narrow wing 1022, the width D1 of the upper wide wing 1021 being greater than or equal to the width D2 of the upper narrow wing 1022. The lower flange 103 includes a lower wide wing 1031 and a lower narrow wing 1032, the width D3 of the lower wide wing 1031 being greater than the width D4 of the lower narrow wing 1032. The upper wide wing 1021 and the lower narrow wing 1032 are located on a first side of the web 101, and the upper narrow wing 1022 and the lower wide wing 1031 are located on a second side of the web 101. Among them, the first side and the second side are the two sides of the web plate opposite each other. The first side of the web plate 101 faces the direction of the vehicle's reversal, and the second side of the web plate 101 faces the direction of the vehicle's forward movement. That is, the upper wide wing 1021 and the lower narrow wing 1032 are distributed on the side of the web plate 101 facing the direction of the vehicle's reversal, and the upper narrow wing 1022 and the lower wide wing 1031 are distributed on the side of the web plate 101 facing the direction of the vehicle's forward movement.

[0071] The I-beam 100 of the fully streamlined near-net-shape front axle forging in the above embodiment adopts an asymmetrical structural design, such that the width D2 of the upper flange of the I-beam in the forward direction of the vehicle, centered on the web, is less than or equal to the width D1 in the reverse direction of the vehicle, and the width D4 of the lower flange of the I-beam in the reverse direction of the vehicle, centered on the web, is less than the width D3 in the forward direction of the vehicle. This reduces the overall width of the upper flange 102 and the overall width of the lower flange 103, and reduces the height and thickness of the web 101. This ensures the strength and stiffness performance of the main stress-bearing parts of the front axle under dynamic load, steering, braking, and acceleration conditions, while eliminating material from areas with excess strength. This minimizes the size of the I-beam, reduces the overall weight of the front axle, achieves lightweight design, saves materials, and reduces costs.

[0072] See Figure 1 , Figure 7 and Figure 8In one embodiment, the width direction of the upper wide wing 1021, the upper narrow wing 1022, the lower wide wing 1031, and the lower narrow wing 1032 is the driving direction of the vehicle, that is, the width direction of the upper flange 102 and the lower flange 103 is parallel to the driving direction of the vehicle.

[0073] See Figure 7 and Figure 8 In one embodiment, the width of the upper wide wing 1021 is 1 to 1.5 times the width of the upper narrow wing 1022, including 1 and 1.5 times, that is, the ratio of width D1 to width D2 is 1 to 1.5. The width ratio includes the end values ​​of 1 and 1.5. The appropriate width ratio makes the stress borne by the upper flange of the front axle I-beam equivalent under various working conditions, and reduces the mass of the part with excess strength.

[0074] See Figure 8 In one embodiment, the width of the lower wide wing 1031 is greater than the width of the lower narrow wing 1032, and the width of the lower wide wing 1031 is less than or equal to 1.5 times the width of the lower narrow wing 1032. That is, the ratio of width D3 to width D4 is 1 to 1.5. The width ratio does not include the end value 1, but includes the end value 1.5. The appropriate width ratio makes the stress borne by the lower flange 103 of the front axle I-beam equivalent under various working conditions, and reduces the mass of the part with excess strength.

[0075] See Figure 8 In one embodiment, the width D1 of the upper wing 1021 is smaller than the width D3 of the lower wing 1031.

[0076] See Figure 8 In one embodiment, the width D2 of the upper narrow wing 1022 is less than or equal to the width D4 of the lower narrow wing 1032.

[0077] See Figure 8 In one embodiment, the width of the upper flange 102 is 55mm to 120mm, that is, the sum of the width D1 and the width D2 is 55mm to 120mm.

[0078] Optionally, the width of the lower flange 103 is 55mm to 120mm, that is, the sum of the widths D3 and D4 is 55mm to 120mm.

[0079] Optionally, the width of the upper flange 102 is smaller than the width of the lower flange 103.

[0080] The lightweight front axle forging described above reduces the width of the upper flange 102 of the I-beam by about 25-35% compared to the width of the conventional upper flange of the front axle, and reduces the width of the lower flange 103 of the I-beam by about 3-7% compared to the width of the conventional lower flange of the front axle. This reduces the weight while ensuring the performance of the front axle, thus balancing the performance of the front axle with the lightweight design.

[0081] See Figure 8 In one embodiment, the thickness D5 of the web 101 is 7mm to 10mm, and the thickness direction of the web 101 is the driving direction of the vehicle, that is, the thickness direction of the web 101 is parallel to the driving direction of the vehicle.

[0082] In the above embodiments, the thickness of the web 101 is reduced by 25-35% compared with the web thickness of the traditional front axle, and the height H of the web 101 is reduced by about 5-8% compared with the traditional front axle, which reduces the weight without affecting the strength and rigidity of the front axle forging.

[0083] See Figure 8 In one embodiment, both the upper flange 102 and the lower flange 103 are perpendicularly connected to the web 101.

[0084] Optionally, the upper flange 102, lower flange 103, and web 101 are an integral structure.

[0085] Optionally, the connection between the upper flange 102, the lower flange 103, and the web 101 is rounded.

[0086] The fully streamlined near-net-shape front axle forging of this application integrates advancements in materials technology, equipment technology, and process technology. It uses non-quenched and tempered steel, and the surface hardness is stable and uniform after controlled temperature cooling, resulting in high strength and minimal deformation. Structural improvements are made to the leaf spring seat and the I-beam section, which not only meet the strength and stiffness requirements of the front axle but also significantly reduce the overall weight of the front axle forging, balancing lightweight design and performance, and improving economic efficiency. In this application, the front axle forging can form a fully streamlined, near-net-shape unmachined leaf spring seat structure during hot straightening, reducing the cross-sectional area of ​​the leaf spring seat and the longitudinal section, thus reducing the overall weight of the forging and the size of the raw material billet. Compared with traditional front axles, the length, width, and thickness of the leaf spring seat are minimized, meaning the cross-sectional area of ​​the front axle is minimized. This reduces the weight of the leaf spring seat portion of the front axle forging by approximately 3-7% and improves the utilization rate of raw materials by approximately 3-7%. Furthermore, improvements to the I-beam section can reduce the overall weight of the front axle forging by approximately 13-17%. The forging inspection process is shortened, requiring only one installation. Inspection can be completed in both pinned and unpinned states without changing the inspection datum, improving the inspection efficiency and accuracy of the forging. At the same time, it achieves the unification of the forging inspection datum and the machining datum, improving the quality and efficiency of machining.

[0087] In the description of this specification, the references to terms such as "this embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0088] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A fully streamlined near-net-shape front shaft forging, characterized in that: The streamlined near-net-shape front axle forging is integrally forged from non-quenched and tempered steel. The surface hardness difference of the streamlined near-net-shape front axle forging is less than or equal to HB20. The streamlined near-net-shape front axle forging includes a kingpin, a bent arm, leaf spring seats, and an I-beam. The two ends of the I-beam are respectively connected to the leaf spring seats. The two leaf spring seats are respectively connected to the kingpin through the bent arm. The symmetry of the centers of the two leaf spring seats with respect to the line connecting the centers of the two kingpins is less than or equal to 1.5 mm. The leaf spring seats are streamlined near-net-shape structures. The upper and lower surfaces of the leaf spring seat are both heat-corrected planes. The flatness of the upper and lower surfaces is less than or equal to 0.8 mm, the flatness between the upper surfaces of the two leaf spring seats is less than or equal to 1.5 mm, and the parallelism between the upper and lower surfaces is less than or equal to 1.3 mm. The upper surface of the leaf spring seat is a smooth and flat surface, and the upper surface has a bright edge band, which accounts for more than 95% of the area of ​​the cut edge of the upper surface. After heat correction, magnetic particle inspection shows no magnetic traces on the upper surface. The I-beam is an asymmetrical structure, comprising a web, an upper flange, and a lower flange. The top and bottom of the web are connected to the upper flange and the lower flange, respectively. The upper flange includes a wide upper wing and a narrow upper wing, the width of which is greater than or equal to the width of which is the narrow upper wing. The lower flange includes a wide lower wing and a narrow lower wing, the width of which is greater than the width of which is the narrow lower wing. The wide upper wing and the narrow lower wing are located on a first side of the web, and the narrow upper wing and the wide lower wing are located on a second side of the web. The first side of the web faces the reversing direction of the vehicle, and the second side of the web faces the forward direction of the vehicle. The width of the wide upper wing is less than the width of the wide lower wing; the width of the narrow upper wing is less than or equal to the width of the narrow lower wing; the width directions of the wide upper wing, the narrow upper wing, the wide lower wing, and the narrow lower wing are in the driving direction of the vehicle.

2. The streamlined near-net-shape front shaft forging according to claim 1, characterized in that: The connection between the upper plane and the curved arm and the I-beam is smoothed by a large rounded corner structure; the large rounded corner structure includes a concave first rounded corner and a convex second rounded corner, one end of the second rounded corner is connected to the upper plane, and the other end of the second rounded corner is connected to the curved arm and the I-beam respectively through the first rounded corner.

3. The streamlined near-net-shape front shaft forging according to claim 2, characterized in that: The radius of the first fillet is R. 11 The R 11 The range is 60–180 mm; the radius of the second fillet is r. 11 The r 11 The range is 3 to 6 mm.

4. The streamlined near-net-shape front shaft forging according to claim 1, characterized in that: Both the upper plane and the lower plane have forged outwardly convex third rounded corners along their width direction.

5. The streamlined near-net-shape front shaft forging according to claim 4, characterized in that: The radius of the third fillet is r. 12 The r 12 The range is 3 to 6 mm.

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