A mold for upsetting and thickening hollow automobile front axle tube blank and its forming method

Abstract

This invention discloses a upset thickening mold and forming method for hollow automotive front axle tube blanks, relating to the field of seamless steel pipe plastic forming technology. The upset thickening mold for hollow automotive front axle tube blanks, used on a three-axis hydraulic press, includes an upper and lower template arranged vertically opposite each other, and two upset die assemblies arranged horizontally opposite each other. A central clamping die assembly for horizontally fixing the tube blank is provided between the upper and lower templates. The two upset die assemblies are respectively used to upset the two ends of the tube blank. Using the upset thickening mold of this invention, the wall thickness of the tube blank ends can be increased by more than 100% in one process, resulting in high production efficiency; moreover, the forming quality is good and the tube blank does not become unstable.

Description

Technical Field

[0001] This invention relates to the field of seamless steel pipe plastic forming technology, specifically to a hollow automobile front axle tube billet upsetting and thickening mold and forming method. Background Technology

[0002] The front axle of a car is one of the most important components of the chassis. During vehicle operation, the front axle needs to withstand loads generated by uneven road surfaces, emergency braking, and continuous cornering, requiring high strength, rigidity, and fatigue life. The front axle generally consists of a crossbeam, two side bends, and a shank.

[0003] Automotive front axles can be categorized based on their manufacturing process into three types: integral forged front axles, steel tube composite welded front axles, and sheet metal stamping and welding front axles. Integral forged front axles are currently the mainstream structure for commercial vehicles. The leaf spring seats are integrally formed with the front axle, reducing the impact of welding and achieving a material utilization rate of 80%–85%. They are widely used in front axles with axle loads of 3.5T–7T. However, the products are relatively heavy, the forging process requires large forging equipment, and mold development costs are high, with limited flexibility in design. Steel tube composite welded front axles have lower bending resistance due to the round tube crossbeam, and the welding quality requirements at both ends of the crossbeam and the leaf spring seats are high. They are mainly used in small front axles with axle loads less than 3.5T. Sheet metal stamping and welding front axles have a relatively simple structure, do not require large forging equipment, and have lower mold development costs. However, the manufacturing process is complex, fatigue life is low, and impact resistance is poor. They are mainly used in engineering vehicles and special vehicles with axle loads greater than 7T and operating at low speeds.

[0004] With the continuous advancement of automotive lightweighting requirements, the market needs to develop a new type of front axle that is lightweight and high-performance. Reports have emerged of seamless steel tube integrally formed hollow automotive front axles.

[0005] Chinese patent [CN115194419A] discloses a method for forming a hollow front axle with a large drop, and discloses the manufacturing process of the hollow front axle: blanking of a round tube blank - thickening - bending - pressing - machining - welding accessories - heat treatment. The whole tube blank is pressed and formed by using a mold to obtain a crossbeam, a bend, and a fist with rectangular cross sections of different sizes. The fist is a rectangular tube with a large rectangular hole and a uniform height, width, and variable wall thickness. The curved surface of the machined end of the fist of the pressed tube blank and the sealing hole are welded and sealed.

[0006] The integral forming of hollow automotive front axles using seamless steel tubes involves significant deformation and thickening of the tube blank ends, as well as the integral forming of rectangular tubes with large height differences. This process is very challenging and has not yet been mass-produced. Existing literature discloses integrally formed hollow automotive front axles using seamless steel tubes with large lengths (generally greater than 2200 mm) and a large length-to-outer-diameter ratio (greater than 13). This requires end thickening of more than 100%, making forming difficult. The middle portion of the tube blank is prone to instability. Multiple hot extrusion methods are typically used, requiring multiple heating processes, which is inefficient and affects the strength of the final tube ends. Summary of the Invention

[0007] In view of the defects existing in the prior art, the purpose of this invention is to provide a mold and forming method for upsetting and thickening hollow automobile front axle tube blanks, which can increase the thickness of the tube blank end by more than 1 times in one process, and the forming quality is high, completely solving the problem of instability in the middle.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a hollow automobile front axle tube blank upsetting and thickening mold, used on a three-way hydraulic press, including an upper template and a lower template arranged vertically opposite each other, and two upsetting mold assemblies arranged horizontally opposite each other; a middle clamping mold assembly for horizontally fixing the tube blank is provided between the upper template and the lower template; the two upsetting mold assemblies are respectively used to upset the two ends of the tube blank.

[0009] Based on the above technical solution, the upsetting die assembly includes a side template, a pad mold, a sleeve, an upsetting die, and an end cap; one end of the sleeve is connected to the pad mold and the side template by screws, and both ends of the pad mold are respectively assembled into the cylindrical hole II of the sleeve and the cylindrical hole of the side template; the other end of the sleeve is connected to the end cap by screws, and the end cap protrusion is assembled into the cylindrical hole I of the sleeve; the outer cylinder of the upsetting die is assembled into the cylindrical hole I of the sleeve, and both ends of the upsetting die abut against the pad mold and the end cap protrusion, respectively, and do not rotate during the upsetting process.

[0010] Based on the above technical solution, the middle clamping mold assembly includes a middle upper clamping mold, a middle upper fixed mold, a middle lower clamping mold, and a middle lower fixed mold; the upper end of the middle upper fixed mold is embedded in the rectangular groove I of the upper template and fixed by screws, and the lower end of the middle upper fixed mold is provided with a middle upper fixed mold semi-cylindrical hole; the middle upper clamping mold is a semi-stepped shaft with flanges at both ends, and the middle upper clamping mold step in the middle of the middle upper clamping mold is assembled in the middle upper fixed mold semi-cylindrical hole, and the middle upper clamping mold... The upper clamping mold flanges at both ends are fixed to the upper fixed mold at the middle by screws; the lower end of the lower fixed mold at the middle is embedded in the rectangular groove I of the lower template and fixed by screws; the upper end of the upper fixed mold at the middle is provided with a semi-cylindrical hole of the lower fixed mold at the middle; the lower clamping mold at the middle is a semi-stepped shaft with flanges at both ends; the lower clamping mold step in the middle of the lower clamping mold is assembled in the semi-cylindrical hole of the lower fixed mold at the middle; the lower clamping mold flanges at both ends of the lower clamping mold at the middle are fixed to the lower fixed mold at the middle by screws.

[0011] Based on the above technical solution, left and right side clamping mold assemblies are arranged opposite to each other on both sides of the central clamping mold assembly;

[0012] Based on the above technical solution, the left and right side clamping mold assembly includes left and right side upper clamping molds, left and right side upper fixed molds, left and right side lower clamping molds, and left and right side lower fixed molds; the upper ends of the left and right side upper fixed molds are embedded in the rectangular grooves II of the upper template and fixed with screws, and the lower ends of the left and right side upper fixed molds are provided with semi-cylindrical holes; the left and right side upper clamping molds are semi-stepped shafts, including a first step of the upper clamping mold, an upper clamping mold flange, and a second step of the upper clamping mold; the upper clamping mold flange is fixed to the left and right side upper fixed molds with screws, and the second step of the upper clamping mold is assembled into the semi-cylindrical holes of the left and right side upper fixed molds. In the cylindrical hole, the first step of the upper clamping mold enters the cylindrical hole of the end cap during upsetting and thickening; the lower ends of the left and right lower fixing molds are embedded in the rectangular groove II of the lower template and fixed by screws, and the upper ends of the left and right lower fixing molds are provided with semi-cylindrical holes; the left and right lower clamping molds are semi-stepped shafts, including the first step of the lower clamping mold, the lower clamping mold flange, and the second step of the lower clamping mold; the lower clamping mold flange is fixed to the left and right lower fixing molds with screws, the second step of the lower clamping mold is assembled in the semi-cylindrical holes of the left and right lower fixing molds, and the first step of the lower clamping mold enters the cylindrical hole of the end cap during upsetting and thickening.

[0013] Based on the above technical solution, the middle lower clamping mold and the left and right lower clamping molds are all provided with a semi-cylindrical cavity with a radius of R2, and the radius R2 is slightly larger than the outer radius R0 of the initial tube blank.

[0014] Based on the above technical solution, the middle upper clamping mold is provided with a semi-cylindrical cavity with a radius of R3, and the left and right upper clamping molds are provided with semi-cylindrical cavities with a radius of R4; the radius R3 is slightly larger than the radius R4, and both R3 and R4 are smaller than the outer radius R0 of the initial tube blank, so that the clamping force between the left and right upper clamping molds and the left and right lower clamping molds is greater than the clamping force between the middle upper clamping mold and the middle lower clamping mold.

[0015] Based on the above technical solution, the radius R2 is 0.3-0.5 mm larger than the outer radius R0 of the initial tube blank; the radius R4 is smaller than the radius R3, and R4 is 0.5-0.8 mm smaller than the outer radius R0 of the initial tube blank, and the radius R3 is 0.3-0.5 mm smaller than the radius R0.

[0016] Based on the above technical solution, the upsetting die has a length of L1, an inner diameter of d1, and an outer diameter of d2, wherein d1 is 2-3 mm larger than the outer diameter d0 of the initial tube blank, and d2 is 90-120 mm larger than d1. L1 is the length L of the thickened area at the end of the upsetting thickened tube blank. 02 2.3-2.7 times; the outer diameter of the end cap protrusion is the same as the outer diameter d2 of the upsetting die, the length of the cylindrical hole of the end cap is L2 and the inner diameter is d3, where d3 is 50-70mm smaller than d2, and L2 = 60-80mm.

[0017] The present invention also provides a forming method based on the above-mentioned upsetting and thickening die for hollow automotive front axle tube blank, comprising the following steps:

[0018] Step 1: Heating both ends of the initial tube blank. The initial tube blank has an outer diameter of d0, a wall thickness of t0, and a length of L0. The lengths of the heating zones at both ends are L. 01 ;

[0019] Step 2: Billet loading. The loading robot places the heated billet at both ends onto the lower clamping mold in the middle and the lower clamping molds on the left and right sides.

[0020] Step 3: Position the tube blank left and right. The left and right sliders of the three-way hydraulic press drive the left and right upsetting die assemblies to feed during the idle stroke, so that the heated ends of the tube blank slide into the cavity of the upsetting die and press against the pad die.

[0021] Step 4: The tube blank is clamped from top to bottom. The main slide of the three-way hydraulic press drives the upper template to move downward. The upper clamping mold on the left and right sides and the lower clamping mold on the left and right sides, as well as the upper clamping mold in the middle and the lower clamping mold in the middle, clamp the tube blank at the same time.

[0022] Step 5: Upsetting and Thickening. The left and right sliders of the three-way hydraulic press drive the left and right upsetting die assemblies to advance by a feed amount of s, thereby upsetting and thickening the ends of the heated tube blank. The outer diameter of the upset and thickened tube blank ends remains basically unchanged, while the wall thickness increases by more than 1 times from the initial t0, with a length of L. 02 ;

[0023] Step 6: The hydraulic press returns. The left and right sliders of the three-way hydraulic press first drive the left and right upsetting die assemblies to return, and then the main slider drives the upper template to return.

[0024] Step 7: The robot retrieves the item.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention can manufacture pipe fittings with large deformation and thickening, and the wall thickness of the pipe fitting after thickening can be more than twice that of the original pipe fitting; the forming quality is good, no serious warping deformation occurs, and the pipe fitting with this wall thickness is formed in one process. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the upsetting and thickening mold for the hollow automobile front axle tube blank in an embodiment of the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the structure after upsetting;

[0029] Figure 3 This is a schematic diagram of the initial tube blank in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the upsetting and thickening tube blank in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the upsetting die assembly in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the sleeve structure in an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the structure of the pad mold in an embodiment of the present invention;

[0034] Figure 8 This is a schematic diagram of the side template structure in an embodiment of the present invention;

[0035] Figure 9 This is a schematic diagram of the end cap structure in an embodiment of the present invention;

[0036] Figure 10 This is a schematic diagram of the upsetting die structure in an embodiment of the present invention;

[0037] Figure 11 This is a schematic diagram of the structure of the middle clamping mold assembly in an embodiment of the present invention;

[0038] Figure 12 This is a schematic diagram of the structure of the upper and lower clamping molds in the middle section of an embodiment of the present invention;

[0039] Figure 13 This is a schematic diagram of the structure of the left and right clamping mold assembly in an embodiment of the present invention;

[0040] Figure 14 This is a schematic diagram of the structure of the upper left and lower left and right clamping molds in an embodiment of the present invention;

[0041] Figure label:

[0042] 1-Upper template; 11-Upper template rectangular groove I; 12-Upper template rectangular groove II;

[0043] 2-Lower template; 21-Lower template rectangular groove I; 22-Lower template rectangular groove II;

[0044] 3-Upsetting die assembly; 31-Sleeve; 311-Sleeve cylindrical hole II; 312-Sleeve cylindrical hole I; 32-Pad die; 33-Side template; 331-Side template cylindrical hole; 34-End cap; 341-End cap protrusion; 342-End cap cylindrical hole; 35-Upsetting die;

[0045] 4-Middle clamping mold assembly; 41-Middle upper fixed mold; 411-Middle upper fixed mold semi-cylindrical hole; 42-Middle upper clamping mold; 421-Middle upper clamping mold flange; 422-Middle upper clamping mold step; 43-Middle lower fixed mold; 431-Middle lower fixed mold semi-cylindrical hole; 44-Middle lower clamping mold; 441-Middle lower clamping mold flange; 442-Middle lower clamping mold step;

[0046] 5-Left and right side clamping mold assembly; 51-Left and right side upper fixed mold; 511-Left and right side upper fixed mold semi-cylindrical hole; 52-Left and right side upper clamping mold; 521-Upper clamping mold flange; 522-Upper clamping mold first step; 523-Upper clamping mold second step; 53-Left and right side lower fixed mold; 531-Left and right side lower fixed mold semi-cylindrical hole; 54-Left and right side lower clamping mold; 541-Lower clamping mold flange; 542-Lower clamping mold first step; 543-Lower clamping mold second step;

[0047] 6-Initial tube blank;

[0048] 7-Upsetting and thickening of tube blank. Detailed Implementation

[0049] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0050] In the description of this invention, it should be noted that the directional terms such as "center", "horizontal (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature. In the description of this invention, "several" or "a number" means two or more, unless otherwise explicitly specified.

[0052] The following description, in conjunction with the accompanying drawings, further illustrates specific embodiments of the present invention, making the technical solution and its beneficial effects clearer and more explicit. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the invention.

[0053] See Figures 1-4 As shown, this embodiment of the invention provides a hollow automobile front axle tube blank upsetting and thickening mold, which is used on a three-way hydraulic press. It includes an upper template 1 and a lower template 2 arranged vertically opposite each other, and two upsetting mold assemblies 3 arranged horizontally opposite each other. A middle clamping mold assembly 4 for horizontally fixing the tube blank is provided between the upper template 1 and the lower template 2. The two upsetting mold assemblies 3 are respectively used to upset the two ends of the tube blank.

[0054] See Figures 5-9 As shown, the upsetting die assembly 3 includes a side template 33, a pad mold 32, a sleeve 31, an upsetting die 35, and an end cap 34. One end of the sleeve 31 is connected to the pad mold 32 and the side template 33 by screws. The two ends of the pad mold 32 are respectively fitted into the cylindrical holes I111 of the sleeve and I311 of the side template. The other end of the sleeve 31 is connected to the end cap 34 by screws. The end cap protrusion 341 is fitted into the cylindrical hole I312 of the sleeve. The outer cylinder of the upsetting die 35 is fitted into the cylindrical hole I312 of the sleeve. The two ends of the upsetting die 35 abut against the pad mold 32 and the end cap protrusion 341, respectively, and do not rotate during the upsetting process.

[0055] See Figures 11-12As shown, the middle clamping mold assembly 4 includes a middle upper clamping mold 42, a middle upper fixed mold 41, a middle lower clamping mold 44, and a middle lower fixed mold 43. The upper end of the middle upper fixed mold 41 is embedded in the rectangular groove I11 of the upper template and fixed by screws. The lower end of the middle upper fixed mold 41 is provided with a middle upper fixed mold semi-cylindrical hole 411. The middle upper clamping mold 42 is a semi-stepped shaft with flanges at both ends. The middle upper clamping mold step 422 in the middle of the middle upper clamping mold 42 is assembled in the middle upper fixed mold semi-cylindrical hole 411. The middle upper part of the middle upper clamping mold 42 is located at both ends of the middle upper part of the upper mold. The clamping mold flange 421 is fixed to the middle upper fixed mold 41 by screws; the lower end of the middle lower fixed mold 43 is embedded in the lower template rectangular groove I21 and fixed by screws; the upper end of the middle upper fixed mold 41 is provided with a middle lower fixed mold semi-cylindrical hole 431; the middle lower clamping mold 44 is a semi-stepped shaft with flanges at both ends; the middle lower clamping mold step 442 in the middle of the middle lower clamping mold 44 is assembled in the middle lower fixed mold semi-cylindrical hole 431; the middle lower clamping mold flanges 441 at both ends of the middle lower clamping mold 44 are fixed to the middle lower fixed mold 43 by screws.

[0056] See Figures 13-14 As shown, left and right clamping mold assemblies 5 are arranged opposite each other on both sides of the central clamping mold assembly 4. Specifically, the left and right clamping mold assemblies 5 include left and right upper clamping molds 52, left and right upper fixing molds 51, left and right lower clamping molds 54, and left and right lower fixing molds 53. The upper ends of the left and right upper fixing molds 51 are embedded in the rectangular groove II12 of the upper template and fixed by screws. The lower ends of the left and right upper fixing molds 51 are provided with left and right upper fixing mold semi-cylindrical holes 511. The left and right upper clamping molds 52 are semi-stepped shafts, including an upper clamping mold first step 522, an upper clamping mold flange 521, and an upper clamping mold second step 523. The upper clamping mold flange 521 is fixed to the left and right upper fixing molds 51 by screws, and the upper clamping mold second step 523 is assembled on the left and right upper clamping molds 54. In the semi-cylindrical hole 511 of the fixed mold, the first step 522 of the upper clamping mold enters the cylindrical hole 342 of the end cap during upsetting and thickening; the lower end of the left and right lower fixed molds 53 is embedded in the rectangular groove II22 of the lower template and fixed by screws, and the upper end of the left and right lower fixed molds 53 is provided with the semi-cylindrical holes 531 of the left and right lower fixed molds; the left and right lower clamping molds 54 are semi-stepped shafts, including the first step 542 of the lower clamping mold, the flange 541 of the lower clamping mold and the second step 543 of the lower clamping mold; the flange 541 of the lower clamping mold is fixed to the left and right lower fixed molds 53 by screws, the second step 543 of the lower clamping mold is assembled in the semi-cylindrical hole 531 of the left and right lower fixed molds, and the first step 542 of the lower clamping mold enters the cylindrical hole 342 of the end cap during upsetting and thickening. The first step of the lower clamping die enters the cylindrical hole of the end cap during upsetting and thickening. Its length is L3 = 60 mm and its outer radius is R1 = 83.5 mm.

[0057] Specifically, both the central lower clamping mold 44 and the left and right lower clamping molds 54 are provided with semi-cylindrical cavities with a radius of R2, and the radius R2 is slightly larger than the outer radius R0 of the initial tube blank 6. In this embodiment, R2 = 60.8 mm. The length of the semi-cylindrical holes of the left and right lower clamping molds is L4, L4 = 300 mm; the length of the semi-cylindrical hole of the central lower clamping mold is L5, L5 = 310 mm.

[0058] Specifically, the upper clamping mold 42 in the middle has a semi-cylindrical cavity with a radius of R3, and the upper clamping molds 52 on the left and right sides have semi-cylindrical cavities with a radius of R4. The radius R3 is slightly larger than the radius R4, and both R3 and R4 are smaller than the outer radius R0 of the initial tube blank 6, so that the clamping force between the upper clamping molds 52 on the left and right sides and the lower clamping molds 54 on the left and right sides is greater than the clamping force between the upper clamping mold 42 in the middle and the lower clamping mold 44 in the middle. In this embodiment, R3 = 60.2 mm and R4 = 60 mm.

[0059] The length of the semi-cylindrical hole of the upper clamping mold in the middle is the same as the length of the semi-cylindrical hole of the lower clamping mold in the middle, L4. The length of the lower clamping mold on the left and right sides is the same as the length of the upper clamping mold on the left and right sides, L5.

[0060] In this embodiment, the total length L of the upset thickened tube blank is... 03 =2030mm, outer diameter d0=φ121mm and wall thickness t0=13mm in the middle section; length L of the thickened area at the left and right ends 02 =150mm, outer diameter d 01 =φ123mm, maximum wall thickness t1=28mm, which is 1.15 times greater than the middle wall thickness t0.

[0061] Specifically, radius R2 is 0.3-0.5 mm larger than the outer radius R0 of the initial tube blank 6; radius R4 is smaller than radius R3, and R4 is 0.5-0.8 mm smaller than the outer radius R0 of the initial tube blank 6, and radius R3 is 0.3-0.5 mm smaller than radius R0.

[0062] Specifically, the upsetting die 35 has a length of L1, an inner diameter of d1, and an outer diameter of d2. d1 is 2-3 mm larger than the outer diameter d0 of the initial tube blank 6, and d2 is 90-120 mm larger than d1. L1 is the length L of the thickened area at the end of the upsetting thickened tube blank 7. 02The outer diameter of the end cap protrusion 341 is the same as the outer diameter d2 of the upsetting die 35. The length of the cylindrical hole 342 of the end cap is L2 and the inner diameter is d3, where d3 is 50-70mm smaller than d2, and L2 = 60-80mm. In this embodiment, the length of the upsetting die is L1, the inner diameter is φd1, and the outer diameter is φd2, where d1 = φ123.5mm, d2 = φ230mm, and L1 = 370mm. The outer diameter of the end cap protrusion is the same as the outer diameter d2 of the upsetting die, and the length of the cylindrical hole of the end cap is L2 = 65mm and the inner diameter d3 = φ170mm.

[0063] This invention also provides a forming method based on the above-mentioned upsetting and thickening die for hollow automotive front axle tube blanks, comprising the following steps:

[0064] Step 1: Heating both ends of the initial tube blank 6. The initial tube blank 6 has an outer diameter of d0, a wall thickness of t0, and a length of L0. The lengths of the heating zones at both ends are L. 01 In this embodiment, the initial tube blank has an outer diameter of d0 = φ121mm, a wall thickness of t0 = 13mm, and a length of L0 = 2240mm. The lengths of the heating zones at both ends are L... 01 =250mm;

[0065] Step 2: Billet loading. The loading robot places the heated billet at both ends onto the lower clamping mold 44 in the middle and the lower clamping molds 54 on the left and right sides.

[0066] Step 3: Position the tube blank left and right. The left and right sliders of the three-way hydraulic press drive the left and right upsetting die assemblies 3 to feed in the idle stroke, so that the heated ends of the tube blank slide into the inner cavity of the upsetting die 35 and press against the pad die 32.

[0067] Step 4: The tube blank is clamped from top to bottom. The main slide of the three-way hydraulic press drives the upper template 1 to move downward. The upper clamping molds 52 on the left and right sides and the lower clamping molds 54 on the left and right sides, as well as the upper clamping mold 42 and the lower clamping mold 44 in the middle, clamp the tube blank at the same time.

[0068] Step 5: Upsetting and Thickening. The left and right sliders of the three-way hydraulic press drive the left and right upsetting die assemblies 3 to feed forward by a feed amount of s, thereby upsetting and thickening the ends of the heated tube blank. The outer diameter of the upset and thickened tube blank 7 ends remains basically unchanged, while the wall thickness increases by more than 1 times from the initial t0, with a length of L. 02 In this embodiment, t0 = 13 mm, s = 105 mm, L 02 =150mm.

[0069] Step 6: The hydraulic press returns. The left and right sliders of the three-way hydraulic press first drive the left and right upsetting die assemblies 3 to return, and then the main slider drives the upper template 1 to return.

[0070] Step 7: The robot retrieves the item.

[0071] In the description of this specification, references to terms such as "an embodiment," "preferred," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. Illustrative expressions of the above terms in this specification 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.

[0072] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A die for upsetting and thickening hollow automotive front axle tube blanks, used on a three-axis hydraulic press, characterized in that: It includes an upper template (1) and a lower template (2) arranged vertically opposite each other, and two upsetting die assemblies (3) arranged horizontally opposite each other; a middle clamping die assembly (4) for horizontally fixing the tube blank is provided between the upper template (1) and the lower template (2); the two upsetting die assemblies (3) are respectively used to upset the two ends of the tube blank; The middle clamping mold assembly (4) includes a middle upper clamping mold (42), a middle upper fixed mold (41), a middle lower clamping mold (44), and a middle lower fixed mold (43). The upper end of the middle upper fixed mold (41) is embedded in the upper template rectangular groove I (11) and fixed by screws. The lower end of the middle upper fixed mold (41) is provided with a middle upper fixed mold semi-cylindrical hole (411). The middle upper clamping mold (42) is a semi-stepped shaft with flanges at both ends. The middle upper clamping mold step (422) in the middle of the middle upper clamping mold (42) is assembled in the middle upper fixed mold semi-cylindrical hole (411). The middle upper clamping mold (42) has flanges at both ends. The clamping mold flange (421) is fixed to the middle upper fixed mold (41) by screws; the lower end of the middle lower fixed mold (43) is embedded in the lower template rectangular groove I (21) and fixed by screws; the upper end of the middle upper fixed mold (41) is provided with a middle lower fixed mold semi-cylindrical hole (431); the middle lower clamping mold (44) is a semi-stepped shaft with flanges at both ends; the middle lower clamping mold step (442) in the middle of the middle lower clamping mold (44) is assembled in the middle lower fixed mold semi-cylindrical hole (431); the middle lower clamping mold flanges (441) at both ends of the middle lower clamping mold (44) are fixed to the middle lower fixed mold (43) by screws; The middle clamping mold assembly (4) has left and right side clamping mold assemblies (5) arranged opposite to each other on both sides. The left and right side clamping mold assembly (5) includes left and right side upper clamping molds (52), left and right side upper fixing molds (51), left and right side lower clamping molds (54), and left and right side lower fixing molds (53); the upper end of the left and right side upper fixing molds (51) is embedded in the upper template rectangular groove II (12) and fixed by screws, and the lower end of the left and right side upper fixing molds (51) is provided with left and right side upper fixing mold semi-cylindrical holes (511); the left and right side upper clamping molds (52) are semi-stepped shafts, including upper clamping mold first step (522), upper clamping mold flange (521), and upper clamping mold second step (523); the upper clamping mold flange (521) is fixed to the left and right side upper fixing molds (51) by screws, and the upper clamping mold second step (523) is assembled in the left and right side upper fixing mold semi-cylindrical holes (511), and the upper clamping mold... The first step (522) of the mold enters the cylindrical hole (342) of the end cap during upsetting and thickening; the lower end of the left and right lower fixing molds (53) is embedded in the rectangular groove II (22) of the lower template and fixed by screws; the upper end of the left and right lower fixing molds (53) is provided with the left and right lower fixing mold semi-cylindrical holes (531); the left and right lower clamping molds (54) are semi-stepped shafts, including the lower clamping mold first step (542), the lower clamping mold flange (541) and the lower clamping mold second step (543); the lower clamping mold flange (541) is fixed to the left and right lower fixing molds (53) with screws; the lower clamping mold second step (543) is assembled in the left and right lower fixing mold semi-cylindrical holes (531); the lower clamping mold first step (542) enters the cylindrical hole (342) of the end cap during upsetting and thickening. The middle lower clamping mold (44) and the left and right lower clamping molds (54) are both provided with a semi-cylindrical cavity with a radius of R2, and the radius R2 is slightly larger than the outer radius R0 of the initial tube blank (6); The upper clamping mold (42) in the middle section is provided with a semi-cylindrical cavity with a radius of R3, and the upper clamping molds (52) on the left and right sides are provided with semi-cylindrical cavities with a radius of R4. The radius R3 is slightly larger than the radius R4, and both R3 and R4 are smaller than the outer radius R0 of the initial tube blank (6), so that the clamping force between the upper clamping molds (52) on the left and right sides and the lower clamping molds (54) on the left and right sides is greater than the clamping force between the upper clamping mold (42) in the middle section and the lower clamping mold (44) in the middle section. The radius R2 is 0.3-0.5 mm larger than the outer radius R0 of the initial tube blank (6); the radius R4 is smaller than the radius R3, and R4 is 0.5-0.8 mm smaller than the outer radius R0 of the initial tube blank (6), and the radius R3 is 0.3-0.5 mm smaller than the radius R0.

2. The upsetting and thickening die for hollow automotive front axle tube blank as described in claim 1, characterized in that: The upsetting die assembly (3) includes a side template (33), a pad mold (32), a sleeve (31), an upsetting die (35), and an end cap (34). One end of the sleeve (31) is connected to the pad mold (32) and the side template (33) by screws. The two ends of the pad mold (32) are respectively fitted into the cylindrical hole II (311) of the sleeve and the cylindrical hole (331) of the side template. The other end of the sleeve (31) is connected to the end cap (34) by screws. The end cap protrusion (341) is fitted into the cylindrical hole I (312) of the sleeve. The outer cylinder of the upsetting die (35) is fitted into the cylindrical hole I (312) of the sleeve. The two ends of the upsetting die (35) abut against the pad mold (32) and the end cap protrusion (341) respectively, and do not rotate during the upsetting process.

3. The upsetting and thickening die for hollow automotive front axle tube blank as described in claim 2, characterized in that: The upsetting die (35) has a length of L1, an inner diameter of d1, and an outer diameter of d2, where d1 is 2-3 mm larger than the outer diameter d0 of the initial tube blank (6), and d2 is 90-120 mm larger than d1. L1 is the length of the thickened area at the end of the upsetting thickened tube blank (7). 02 2.3-2.7 times; the outer diameter of the end cap protrusion (341) is the same as the outer diameter d2 of the upsetting die (35), the length of the end cap cylindrical hole (342) is L2 and the inner diameter is d3, where d3 is 50-70mm smaller than d2, and L2=60-80mm.

4. A forming method based on the upsetting and thickening die for hollow automobile front axle tube blanks according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step 1: Heating both ends of the initial tube blank (6). The initial tube blank (6) has an outer diameter of d0, a wall thickness of t0, and a length of L0. The lengths of the heating zones at both ends are L. 01 ; Step 2: Billet loading. The loading robot places the heated billet at both ends onto the middle lower clamping mold (44) and the left and right lower clamping molds (54). Step 3: Position the tube blank left and right. The left and right sliders of the three-way hydraulic press drive the left and right upsetting die assemblies (3) to feed during the idle stroke, so that the heated ends of the tube blank slide into the cavity of the upsetting die (35) and press against the pad die (32). Step 4: The tube blank is clamped from top to bottom. The main slide of the three-way hydraulic press drives the upper template (1) to move downward. The upper clamping mold (52) on the left and right sides and the lower clamping mold (54) on the left and right sides, as well as the upper clamping mold (42) and the lower clamping mold (44) in the middle, clamp the tube blank at the same time. Step 5: Upsetting and thickening. The left and right sliders of the three-way hydraulic press drive the left and right upsetting die assemblies (3) to feed, with a feed amount of s, so that the ends of the tube blank heated at both ends are upset and thickened. The outer diameter of the upset and thickened tube blank (7) ends remains basically unchanged, and the wall thickness increases by more than 1 times from the initial t0, with a length of L. 02 ; Step 6: The hydraulic press returns. The left and right sliders of the three-way hydraulic press first drive the left and right upsetting die assemblies (3) to return, and then the main slider drives the upper template (1) to return. Step 7: The robot retrieves the item.

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