Clutch hub forming method, die, and clutch hub

Abstract

This disclosure relates to a method for forming a clutch hub, a mold, and a clutch hub. The method for forming a clutch hub includes: obtaining an aluminum alloy melt; providing an extrusion casting mold for the clutch hub and filling the extrusion casting mold's cylinder with the aluminum alloy melt; pressing and holding the aluminum alloy melt after filling to form a solidified aluminum alloy casting; performing an incomplete solution treatment on the solidified aluminum alloy casting; performing an aging treatment on the aluminum alloy casting after the incomplete solution treatment; and finishing the outer surface and inner assembly surfaces of the aging aluminum alloy casting to obtain the finished clutch hub.

Description

Technical Field

[0001] This disclosure relates to the field of clutch processing, and in particular to a method for forming a clutch hub, a mold, and a clutch hub. Background Technology

[0002] The clutch is a common component in mechanical transmissions, consisting of a clutch hub, friction plates, steel plates, shaft, and bearings. During operation, the clutch engages or disengages torque transmission through the pressing and releasing of the friction plates against the clutch hub. As a key component for torque transmission, the precision and strength of the clutch hub directly affect the performance and lifespan of the gearbox.

[0003] A clutch hub typically consists of a splined area with circumferential teeth for mating with the friction plates and an annular hub base. The machining quality of the circumferential teeth in the splined area directly affects the assembly accuracy between the clutch hub and the friction plates. The hub base connects to the shaft, transmitting torque, and also meshes with the piston, ensuring that the piston engages the steel plates with the friction plates under hydraulic pressure.

[0004] In related technologies, in order to meet the mechanical performance requirements of the clutch hub, the clutch hub is usually formed by two methods: stamping and forming in one piece, and processing and welding the upper and lower parts separately. Summary of the Invention

[0005] The inventors discovered through research that the stamping one-piece forming method in related technologies is a plastic deformation process. During the stamping process, the material flows under stress, resulting in different thinning rates in different areas. Uneven thickness causes the tooth tip roundness to fail to meet dimensional requirements, leading to poor circumferential tooth profile machining quality and consequently insufficient assembly precision between the clutch hub and friction plates. Furthermore, the method of processing and welding the upper and lower parts separately presents problems such as complex processing steps, high manufacturing costs, and difficulty in ensuring the coaxiality of the hub after welding.

[0006] In view of this, the present disclosure provides a clutch hub forming method, a mold, and a clutch hub, which can improve the processing quality of the clutch hub while meeting the mechanical performance requirements of the clutch hub.

[0007] In one aspect of this disclosure, a method for forming a clutch hub body is provided, comprising:

[0008] Obtain aluminum alloy melt;

[0009] A die for extrusion casting of the clutch hub is provided, and the molten aluminum alloy is filled into the barrel of the die for extrusion casting.

[0010] After the aluminum alloy melt has been filled into the mold, it is pressurized and held to form a solidified aluminum alloy casting.

[0011] The solidified aluminum alloy casting is subjected to incomplete solution treatment.

[0012] Aging treatment is performed on aluminum alloy castings that have undergone incomplete solution treatment.

[0013] The outer surface and inner assembly surface of the aluminum alloy casting that has undergone aging treatment are precision machined to obtain the finished clutch hub body.

[0014] In some embodiments, the pressure holding step includes:

[0015] Apply pressure at 200-300 MPa and hold for 30-40 seconds.

[0016] In some embodiments, the extrusion casting mold includes a moving mold assembly, a fixed mold assembly, a material cylinder seat, a first mechanical locking mechanism, and a second mechanical locking mechanism. The material cylinder is disposed on the material cylinder seat. The fixed mold assembly is located on the upper side of the material cylinder seat and can be locked to the material cylinder seat by the first mechanical locking mechanism. The moving mold assembly is located on the upper side of the fixed mold assembly and can move relative to the fixed mold assembly to form a cavity communicating with the material cylinder. It can also be locked to the fixed mold assembly by the second mechanical locking mechanism.

[0017] The step of providing an extrusion casting mold for the clutch hub and filling the cylinder of the extrusion casting mold with molten aluminum alloy includes:

[0018] The extrusion casting mold is preheated;

[0019] The moving mold assembly is moved upward relative to the fixed mold assembly, and a release agent is sprayed onto the portions of the moving mold assembly and the fixed mold assembly that form the cavity, respectively.

[0020] The moving mold assembly moves downward relative to the fixed mold assembly and closes with the fixed mold assembly. Then, the moving mold assembly and the fixed mold assembly are locked by the second mechanical locking mechanism.

[0021] The moving mold assembly and the fixed mold assembly of the mold closing assembly are moved upward relative to the material cylinder seat, and a portion of the molten aluminum alloy is filled into the material cylinder;

[0022] The moving mold assembly and the fixed mold assembly are moved downward relative to the material cylinder seat and closed with the material cylinder seat. Then, the fixed mold assembly is locked to the material cylinder seat by the first mechanical locking mechanism.

[0023] A portion of the molten aluminum alloy is injected into the cavity through the barrel at a speed of 0.1 to 0.4 m / s.

[0024] In some embodiments, the step of preheating the extrusion casting mold includes:

[0025] The extrusion casting mold is preheated to maintain its temperature at 160-220°C.

[0026] In some embodiments, the step of performing incomplete solution treatment on the aluminum alloy casting includes:

[0027] The solidified aluminum alloy casting is removed from the extrusion casting mold and placed in water at 60-100°C to cool.

[0028] In some embodiments, the step of aging an aluminum alloy casting that has undergone incomplete solution treatment includes:

[0029] The aluminum alloy castings that have undergone non-solution treatment are held in a heat treatment furnace at 170-200℃ for 5-8 hours, and then removed from the furnace and air-cooled.

[0030] In some embodiments, the aluminum alloy melt has the following composition by mass percentage (wt%): Si: 7-9, Cu: 2-4, Mg: 0.4-0.8, Mn: 0.3-0.6, Fe: 0.1-0.4, Ni: 0.4-0.6, Sr: 0.1-0.3, with the remainder being Al and unavoidable impurities, and the total amount of impurities ≤ 0.4%.

[0031] In some embodiments, the step of obtaining aluminum alloy melt includes:

[0032] According to the composition of the aluminum alloy melt by mass percentage (wt%), weigh out the following: aluminum ingots, aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, aluminum-nickel alloy, magnesium ingots encased in aluminum-copper alloy, and aluminum-strontium alloy.

[0033] Aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots encased in aluminum-copper alloys, and aluminum-strontium alloys are symmetrically taken in a melting furnace and smelted to obtain the aluminum alloy melt.

[0034] In some embodiments, prior to the step of melting and weighing the aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, or aluminum-nickel alloys, the method further includes:

[0035] The weighed aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys are placed in a drying furnace and preheated at a temperature of 150-250°C.

[0036] In some embodiments, the step of smelting symmetrically selected aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots encased in aluminum-copper alloys, and aluminum-strontium alloys in a smelting furnace includes:

[0037] Preheated aluminum ingots are added to a melting furnace and heated to 700-760°C to melt the aluminum ingots into molten aluminum.

[0038] The aluminum-silicon alloy, the aluminum-copper alloy, the aluminum-manganese alloy, and the aluminum-nickel alloy are weighed and added to the molten aluminum in order of increasing melting point, so as to melt the aluminum-silicon alloy, the aluminum-copper alloy, the aluminum-manganese alloy, and the aluminum-nickel alloy.

[0039] Add the weighed magnesium ingots encased in an aluminum-copper alloy and stir electromagnetically.

[0040] A rotary degassing method is used to introduce nitrogen or inert gas into the bottom of the smelting furnace for degassing.

[0041] Add the weighed aluminum-strontium alloy and perform a modification treatment;

[0042] A slag remover is added to the smelting furnace to remove slag.

[0043] In some embodiments, the clutch hub includes a hub base and a cylindrical structure integrally formed with the hub base, the cylindrical structure having an internal spline, the internal spline including a plurality of key teeth arranged circumferentially;

[0044] The steps for finishing the outer surface and inner assembly surfaces of the aluminum alloy castings that have undergone aging treatment include:

[0045] The aluminum alloy casting that has undergone aging treatment is precision machined on both axial end faces of the portion corresponding to the hub base, as well as on the outer peripheral surface and axial end face of the portion corresponding to the cylindrical structure.

[0046] Annular grooves for mounting friction plates are machined on the aluminum alloy castings that have undergone aging treatment, corresponding to the plurality of key teeth.

[0047] In one aspect of this disclosure, a clutch hub body is provided, which is obtained by the aforementioned clutch hub body forming method.

[0048] In some embodiments, the clutch hub has a hardness ≥150HBW, a yield strength ≥320MPa, a tensile strength ≥400MPa, and an elongation after fracture ≥4%.

[0049] In some embodiments, the clutch hub includes a hub base and a cylindrical structure integrally formed with the hub base. The cylindrical structure has an internal spline, which includes a plurality of key teeth arranged circumferentially. The surface roughness Ra of the plurality of key teeth is ≤1.6μm, and the tooth profile accuracy is grade 7-8.

[0050] In one aspect of this disclosure, a squeeze casting mold is provided for the aforementioned clutch hub forming method, comprising:

[0051] The material cylinder seat is equipped with a material cylinder;

[0052] A fixed mold assembly is located on the upper side of the material cylinder seat and has a recess. The bottom of the recess can communicate with the material cylinder when the fixed mold assembly and the material cylinder seat are closed.

[0053] A moving mold assembly is located above the fixed mold assembly and has a protrusion that can be inserted into the recess when the moving mold assembly and the fixed mold assembly are closed to form a cavity with the recess.

[0054] A first mechanical locking mechanism is configured to lock the fixed mold assembly and the material cylinder seat when the fixed mold assembly and the material cylinder seat are closed; and

[0055] The second mechanical locking mechanism is configured to lock the moving mold assembly and the fixed mold assembly when the moving mold assembly and the fixed mold assembly are closed.

[0056] In some embodiments, the first mechanical locking mechanism includes:

[0057] The first locking block is disposed on the outer wall of the material cylinder seat;

[0058] A second locking block is disposed on the outer wall of the mold assembly; and

[0059] A first U-lock is used to lock the relative positions of the first locking block and the second locking block.

[0060] In some embodiments, the second mechanical locking mechanism includes:

[0061] A third locking block is disposed on the outer wall of the fixed mold assembly;

[0062] A fourth locking block is disposed on the outer wall of the moving mold assembly; and

[0063] A second U-shaped lock is used to lock the relative positions of the third locking block and the fourth locking block.

[0064] In some embodiments, the clutch hub includes a hub base and a cylindrical structure integrally formed with the hub base. The cylindrical structure has an internal spline, which includes a plurality of key teeth arranged circumferentially. The inner wall of the recess has an axial draft angle of 0.3°, the region of the protrusion corresponding to the tooth tips of the plurality of key teeth has an axial draft angle of 0.5°, and the region of the protrusion corresponding to the tooth flank surfaces of the plurality of key teeth has an axial draft angle of 0.3°.

[0065] In some embodiments, the extrusion casting mold further includes:

[0066] An ejector pin assembly is located above the moving mold assembly and has multiple ejector pins that can pass through the moving mold assembly and be used for demolding solidified aluminum alloy castings.

[0067] Therefore, according to the embodiments of this disclosure, an aluminum alloy molten material is extruded into a clutch hub using an extrusion casting mold. The resulting aluminum alloy casting is then subjected to incomplete solution treatment and aging treatment. Finally, the outer surface and inner assembly surfaces of the aged aluminum alloy casting are precision machined to obtain the finished clutch hub. The aluminum alloy casting obtained by extrusion casting has high forming quality and is very dense, which is beneficial for forming and processing. It can also be used for heat treatment to improve performance, in order to meet the performance requirements of a high-precision, high-strength, and high-toughness hub. Furthermore, the incomplete solution treatment of the obtained aluminum alloy casting can effectively save energy consumption and production cycle, which is beneficial for improving production efficiency and reducing costs. Compared with the high thermal stress caused by high temperature during complete solution treatment, this embodiment can reduce the generation of thermal stress, thereby reducing the risk of deformation or cracking of the aluminum alloy casting. Attached Figure Description

[0068] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0069] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein:

[0070] Figure 1 This is a schematic flowchart of a clutch hub forming method according to some embodiments of the present disclosure;

[0071] Figure 2 This is a cross-sectional schematic diagram of an extrusion casting mold according to some embodiments of the present disclosure;

[0072] Figure 3 This is a schematic diagram of the process of melting aluminum alloy melt in a clutch hub forming method according to some embodiments of the present disclosure;

[0073] Figure 4 This is a schematic flowchart of the extrusion casting process in a clutch hub forming method according to some embodiments of the present disclosure;

[0074] Figure 5 This is a schematic diagram of the structure of a clutch hub according to some embodiments of the present disclosure.

[0075] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components. Detailed Implementation

[0076] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0077] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0078] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0079] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0080] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0081] Figure 1 This is a schematic flowchart of a clutch hub forming method according to some embodiments of the present disclosure. Figure 2 This is a cross-sectional schematic diagram of an extrusion casting mold according to some embodiments of the present disclosure.

[0082] refer to Figure 1 and Figure 2This disclosure provides a method for forming a clutch hub, including steps S1 to S6.

[0083] In step S1, an aluminum alloy melt is obtained.

[0084] In step S2, an extrusion casting mold for the clutch hub is provided, and the molten aluminum alloy is filled into the barrel 11 of the extrusion casting mold.

[0085] In step S3, after the aluminum alloy melt has been filled, it is pressurized and held to form a solidified aluminum alloy casting.

[0086] In step S4, the solidified aluminum alloy casting is subjected to incomplete solution treatment.

[0087] In step S5, the aluminum alloy casting that has undergone incomplete solution treatment is subjected to aging treatment;

[0088] In step S6, the outer surface and inner assembly surface of the aluminum alloy casting that has undergone aging treatment are precision machined to obtain the finished clutch hub body.

[0089] In this embodiment, the aluminum alloy melt filled into the mold is extruded and cast using an extrusion casting mold for the clutch hub body. Then, the resulting aluminum alloy casting is subjected to incomplete solution treatment and aging treatment. Finally, the outer surface and inner assembly surface of the aged aluminum alloy casting are finished to obtain the finished clutch hub body.

[0090] In related technologies, aluminum alloy workpieces can also be formed using die casting. Die casting is typically used for thin-walled parts, and although the processing speed is fast, the density is insufficient, making it unsuitable for heat treatment. Furthermore, the aluminum alloy grades used cannot meet the performance requirements of the clutch hub. In contrast, the aluminum alloy casting obtained by queeze casting used in this embodiment has higher forming quality and is very dense, which is beneficial for forming and processing. It can also be used for heat treatment to improve performance, thereby achieving the performance requirements of a high-precision, high-strength, and tough hub.

[0091] Compared to the stamping integral forming method and the upper and lower parts processing and welding forming method in related technologies, considering the complex structure of the clutch hub and the large variation in wall thickness, the aluminum alloy casting obtained by extrusion casting in this embodiment has higher forming quality, which is convenient for subsequent precision machining and can achieve higher processing quality.

[0092] In addition, the incomplete solution treatment of the obtained aluminum alloy castings can effectively save energy consumption and production cycle, which is conducive to improving production efficiency and reducing costs. Compared with the high thermal stress caused by high temperature during complete solution treatment, this embodiment can reduce the generation of thermal stress, thereby reducing the risk of deformation or cracking of aluminum alloy castings.

[0093] In some embodiments, the aluminum alloy melt obtained in step S1 has the following composition by mass percentage (wt%):

[0094] Si: 7~9, can be 7, 7.5, 8, 8.5 or 9;

[0095] Cu: 2 to 4, which can be 2, 2.5, 3, 3.5 or 4;

[0096] Mg: 0.4–0.8, optionally 0.4, 0.5, 0.6, 0.7, or 0.8;

[0097] Mn: 0.3~0.6, which can be selected as 0.3, 0.4, 0.5 or 0.6;

[0098] Fe: 0.1–0.4, which can be selected as 0.1, 0.2, 0.3, or 0.4;

[0099] Ni: 0.4~0.6, selectable as 0.4, 0.45, 0.5, 0.55 or 0.6;

[0100] Sr: 0.1~0.3, selectable as 0.1, 0.15, 0.2, 0.25 or 0.3;

[0101] The remainder consists of Al and unavoidable impurities, with the total impurity ≤ 0.4, which can be selected as 0.4, 0.35, 0.3, 0.25, 0.2 or 0.1.

[0102] In this aluminum alloy melt, appropriate amounts of Si and Mn can improve its fluidity, achieving a good filling effect; appropriate amounts of Mg, Ni, and Fe can increase the strength of the aluminum alloy and improve the toughness of the clutch hub; appropriate amounts of Sr can improve the morphology of eutectic silicon, enhancing the toughness of the clutch hub; and appropriate amounts of Cu can improve the strength and heat treatment properties of the aluminum alloy, as well as enhance the corrosion resistance of the clutch hub. Combined with the aforementioned extrusion casting and heat treatment processes, a high-precision, high-strength, and high-toughness aluminum alloy clutch hub can be obtained.

[0103] According to the above-mentioned composition in wt%, in some embodiments, the step of obtaining the aluminum alloy melt in step S1 includes: weighing aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots encased in aluminum-copper alloys, and aluminum-strontium alloys according to the composition of the aluminum alloy melt in wt% by mass; and smelting the symmetrically taken aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots encased in aluminum-copper alloys, and aluminum-strontium alloys in a smelting furnace to obtain the aluminum alloy melt.

[0104] Using magnesium ingots encased in an aluminum-copper alloy during the smelting process can reduce magnesium oxidation, thereby reducing oxide impurities in the aluminum alloy.

[0105] In some embodiments, before the step of melting and weighing the aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys, the method further includes: placing the weighed aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys into a drying furnace and preheating them at a preheating temperature of 150-250°C.

[0106] Preheating aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys to 150-250°C (e.g., 150°C, 175°C, 200°C, 225°C, or 250°C) helps improve melting efficiency, enhances temperature uniformity among various materials, and facilitates the production of more uniform aluminum alloy melts.

[0107] Figure 3 This is a schematic diagram of the process of melting aluminum alloy melt in a clutch hub forming method according to some embodiments of the present disclosure.

[0108] refer to Figure 3 In some embodiments, the steps of smelting the aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots wrapped in aluminum-copper alloys, and aluminum-strontium alloys symmetrically taken in the smelting furnace include steps S11 to S16.

[0109] In step S11, the preheated aluminum ingot is added to the melting furnace and heated to 700-760°C (e.g., 700°C, 710°C, 720°C, 730°C, 740°C, 750°C or 760°C) to melt the aluminum ingot into molten aluminum.

[0110] In step S12, the weighed aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, and aluminum-nickel alloy are added to the molten aluminum in order of increasing melting point, so as to melt the aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, and aluminum-nickel alloy.

[0111] In step S13, a weighed magnesium ingot wrapped in an aluminum-copper alloy is added and electromagnetically stirred.

[0112] In step S14, nitrogen or inert gas is introduced into the bottom of the smelting furnace using a rotary degassing method for degassing.

[0113] In step S15, the weighed aluminum-strontium alloy is added and subjected to modification treatment.

[0114] In step S16, a slag remover is added to the smelting furnace to remove slag.

[0115] In step S15 above, an aluminum-strontium alloy for modification treatment is added after degassing. This not only achieves modification treatment but also prevents the strontium element from being melted and lost over a long period of time if it is added earlier.

[0116] In the above embodiment, the step of pressurizing and holding in step S3 includes: applying pressure at a compression pressure of 200-300 MPa (e.g., 200 MPa, 220 MPa, 250 MPa, 280 MPa or 300 MPa) and holding it for 30-40 seconds (e.g., 30s, 35s or 40s).

[0117] By using greater extrusion pressure during pressurization, the casting can be solidified under high pressure, reducing the possibility of shrinkage cavities and effectively improving the density of the aluminum alloy hub, thus meeting the density requirements of the clutch hub under load.

[0118] Figure 4 This is a schematic flowchart of the extrusion casting process in a clutch hub forming method according to some embodiments of the present disclosure.

[0119] refer to Figure 2 The extrusion casting mold shown includes a moving mold assembly 30, a fixed mold assembly 20, a material cylinder seat 10, a first mechanical locking mechanism 40, and a second mechanical locking mechanism 50. The material cylinder 11 is disposed on the material cylinder seat 10. The fixed mold assembly 20 is located above the material cylinder seat 10 and can be locked to the material cylinder seat 10 by the first mechanical locking mechanism 40. The moving mold assembly 30 is located above the fixed mold assembly 20 and can move relative to the fixed mold assembly 20 to form a cavity communicating with the material cylinder 11. It can also be locked to the fixed mold assembly 20 by the second mechanical locking mechanism 50.

[0120] Accordingly, refer to Figure 4 In some embodiments, the step of providing the extrusion casting mold for the clutch hub body in step S2 and filling the barrel 11 of the extrusion casting mold with the molten aluminum alloy includes steps S21 to S26.

[0121] In step S21, the extrusion casting mold is preheated. Extrusion casting can be performed on a dedicated vertical hydraulic press. The extrusion casting mold is pre-installed on the hydraulic press and preheated to maintain the temperature of the extrusion casting mold at 160-220°C (e.g., 160°C, 180°C, 200°C, or 220°C).

[0122] In step S22, the moving mold assembly 30 is moved upward relative to the fixed mold assembly 20, and release agent is sprayed onto the portions of the moving mold assembly 30 and the fixed mold assembly 20 that form the mold cavity. If the moving mold assembly 30 and the fixed mold assembly 20 have been previously locked by the second mechanical locking mechanism 50, the second mechanical locking mechanism 50 can be opened first, and the moving mold assembly 30 can be moved upward relative to the fixed mold assembly 20. Then, a suitable amount of release agent can be sprayed onto the mold cavity using a special spray gun.

[0123] In step S23, the moving mold assembly 30 is moved downward relative to the fixed mold assembly 20 and closes with the fixed mold assembly 20. Then, the moving mold assembly 30 and the fixed mold assembly 20 are locked by the second mechanical locking mechanism 50.

[0124] In step S24, the moving mold assembly 30 and the fixed mold assembly 20 are moved upward relative to the material cylinder seat 10, and a portion of the molten aluminum alloy is filled into the material cylinder 11.

[0125] In step S25, the moving mold assembly 30 and the fixed mold assembly 20 are moved downward relative to the material cylinder seat 10 and closed with the material cylinder seat 10. Then, the fixed mold assembly 20 is locked to the material cylinder seat 10 by the first mechanical locking mechanism 40.

[0126] In step S26, a portion of the molten aluminum alloy is injected into the mold cavity through the barrel 11 at a speed of 0.1–0.4 m / s. Specifically, the molten aluminum alloy can be pushed by a piston to slowly fill the mold. After filling is completed, a pressure holding procedure is immediately started to solidify the aluminum alloy solution under high pressure.

[0127] In this embodiment, in order to apply a larger extrusion pressure of 200-300 MPa during pressurization, steps S23 and S25 respectively employ the first mechanical locking mechanism and the second mechanical locking mechanism to lock the mold during mold closing, thereby preventing the aluminum alloy melt from being squeezed out of the gap when subjected to a large extrusion pressure.

[0128] In some embodiments, step S4, which involves performing incomplete solution treatment on the aluminum alloy casting, includes: removing the solidified aluminum alloy casting from the extrusion casting mold and immersing it in water at 60-100°C for cooling.

[0129] By directly immersing the solidified aluminum alloy casting in water for cooling, the residual heat of the casting is utilized, eliminating the need for traditional air cooling and reheating to high temperatures, thus saving energy consumption. By omitting the air cooling and reheating steps, the manufacturing cycle is effectively shortened, and production efficiency is improved. Furthermore, it reduces the use of heating equipment and energy, contributing to cost reduction.

[0130] In some embodiments, step S5, which involves aging the aluminum alloy casting that has undergone incomplete solution treatment, includes: holding the aluminum alloy casting that has undergone incomplete solution treatment in a heat treatment furnace at 170-200°C (e.g., 170°C, 180°C, 190°C, or 200°C) for 5-8 hours (5h, 6h, 7h, or 8h), and then removing it from the furnace and air-cooling it.

[0131] By aging aluminum alloy castings that have undergone incomplete solution treatment at 170-200℃ for 5-8 hours, internal stresses can be effectively eliminated, the microstructure and dimensions stabilized, and mechanical properties improved.

[0132] Figure 5 This is a schematic diagram of the structure of a clutch hub according to some embodiments of the present disclosure.

[0133] refer to Figure 5 In some embodiments, the clutch hub includes a hub base HS and a cylindrical structure HT integrally formed with the hub base HS. The cylindrical structure HT has an internal spline IS, which includes a plurality of key teeth arranged circumferentially. Accordingly, step S6, which involves finishing the outer surface and inner assembly surface of the aged aluminum alloy casting, includes: finishing the two axial end faces of the portion of the aged aluminum alloy casting corresponding to the hub base HS, and the outer peripheral surface and axial end faces of the portion corresponding to the cylindrical structure HT; and machining annular grooves RG for mounting friction plates on the aged aluminum alloy casting corresponding to the plurality of key teeth.

[0134] The clutch hub obtained by the clutch hub forming method of the above embodiment can obtain good mechanical properties: the clutch hub has a hardness ≥150HBW, a yield strength ≥320MPa, a tensile strength ≥400MPa, and an elongation after fracture ≥4%.

[0135] for Figure 5 The clutch hub shown includes a hub base HS and a cylindrical structure HT integrally formed with the hub base HS. The cylindrical structure HT has an internal spline IS, which includes multiple key teeth arranged circumferentially. The surface roughness Ra of the multiple key teeth is ≤1.6μm, and the tooth profile accuracy is grade 7-8. The surface roughness and tooth profile accuracy requirements are met without the need for finishing of the key teeth's surface.

[0136] The following examples illustrate the clutch hub forming process and the performance of the resulting clutch hub.

[0137] Example 1

[0138] In this embodiment, the aluminum alloy melt has the following composition by mass percentage (wt%): Si 8%, Cu 3%, Mg 0.6%, Mn 0.5%, Fe 0.3%, Ni 0.5%, Sr 0.2%, with the remainder being Al and unavoidable impurities, and the total amount of impurity elements ≤0.4%.

[0139] 1. A certain amount of aluminum ingots (i.e., pure aluminum ingots), aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys are preheated in a drying furnace at a preheating temperature of 150℃.

[0140] 2. Add aluminum ingots to the melting furnace and heat to 700℃ to melt them. Add aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, and aluminum-nickel alloy until the raw materials melt. Add magnesium ingots encased in aluminum-copper alloy using a press-fit method and stir electromagnetically for 10 minutes.

[0141] 3. Use a rotary degassing method, introducing nitriding or inert gas into the bottom of the melting furnace for 10 minutes. Add aluminum-strontium alloy for modification treatment. Add a slag remover to the melting furnace for slag removal treatment.

[0142] 4. A measured amount of refined aluminum alloy molten material is poured into a casting cylinder for extrusion casting. The hydraulic press has a clamping force of 450 tons, a mold temperature of 160℃, and the pressure head moves at a speed of 0.1 m / s, pushing the aluminum alloy molten material through the gating system into the mold cavity. After filling, a high pressure of 200 MPa is applied and maintained for 30 seconds to allow the casting to solidify under high pressure, thus preventing shrinkage cavities. After the pressure holding period, the mold is opened, the casting is removed, and it is quickly placed in water at 60-100℃ for cooling.

[0143] 5. Place the hub casting into a 170℃ heat treatment furnace, hold for 5 hours, and then air cool after removal from the furnace.

[0144] 6. According to the technical requirements of the drawings, perform precision machining on the upper and lower end faces, outer surface and assembly surface of the hub body to obtain the final product.

[0145] The clutch hub prepared by the above method was subjected to non-destructive testing, hardness, tensile testing, surface roughness and tooth profile accuracy testing. It was found that there were no defects such as pores, looseness and shrinkage cavities inside. The hardness was 150HBW, the yield strength was 335MPa, the tensile strength was 415MPa, the elongation after fracture was 6%, the tooth surface roughness Ra was 1.4μm, and the tooth profile accuracy was grade 7.

[0146] Example 2

[0147] In this embodiment, the aluminum alloy melt has the following composition by mass percentage (wt%): Si 8%, Cu 3%, Mg 0.6%, Mn 0.5%, Fe 0.3%, Ni 0.5%, Sr 0.2%, with the remainder being Al and unavoidable impurities, and the total amount of impurity elements ≤0.4%.

[0148] The method for preparing the aluminum alloy clutch hub in this embodiment includes the following steps:

[0149] 1. A certain amount of aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys are preheated in a drying furnace at a preheating temperature of 200℃.

[0150] 2. Add aluminum ingots to the melting furnace and heat to 730℃ to melt them. Add aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, and aluminum-nickel alloy until the raw materials melt. Add magnesium ingots encased in an aluminum-copper alloy sheath using a press-in method, and stir electromagnetically for 10 minutes.

[0151] 3. Use a rotary degassing method, introducing nitriding or inert gas into the bottom of the melting furnace for 10 minutes. Add aluminum-strontium alloy for modification treatment. Add a slag remover to the melting furnace for slag removal treatment.

[0152] 4. A measured amount of refined aluminum alloy molten material is poured into a casting cylinder for extrusion casting. The hydraulic press has a clamping force of 450 tons, a mold temperature of 180℃, and the pressure head moves at a speed of 0.2 m / s, pushing the aluminum alloy molten material through the gating system into the mold cavity. After filling, a high pressure of 250 MPa is applied and maintained for 35 seconds to allow the casting to solidify under high pressure, thus preventing shrinkage cavities. After the pressure holding period, the mold is opened, the casting is removed, and it is quickly placed in water at 60-100℃ for cooling.

[0153] 5. Place the hub casting into a 180℃ heat treatment furnace, hold for 6 hours, and then air cool after removal from the furnace.

[0154] 6. According to the technical requirements of the drawings, perform precision machining on the upper and lower end faces, outer surface and assembly surface of the hub body to obtain the final product.

[0155] The clutch hub prepared by the above method was tested for hardness, tensile strength, surface roughness and tooth profile accuracy. Its hardness was 156HBW, yield strength was 368MPa, tensile strength was 435MPa, elongation after fracture was 5.5%, tooth surface roughness Ra was 1.2μm and tooth profile accuracy was grade 8.

[0156] Example 3

[0157] In this embodiment, the aluminum alloy melt has the following composition by mass percentage (wt%): Si 9%, Cu 4%, Mg 0.8%, Mn 0.6%, Fe 0.4%, Ni 0.6%, Sr 0.3%, with the remainder being Al and unavoidable impurities, and the total amount of impurity elements ≤0.4%.

[0158] The method for preparing the aluminum alloy clutch hub in this embodiment includes the following steps:

[0159] 1. A certain amount of aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys are preheated in a drying furnace at a preheating temperature of 250℃.

[0160] 2. Add aluminum ingots to the melting furnace and heat to 760℃ to melt them. Add aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, and aluminum-nickel alloy until the raw materials melt. Add magnesium ingots encased in aluminum-copper alloy using a press-fit method and stir electromagnetically for 10 minutes.

[0161] 3. Using a rotary degassing method, nitriding or inert gas is introduced into the bottom of the melting furnace for 20 minutes for degassing. An aluminum-strontium alloy is added for modification treatment. A slag remover is then added to the melting furnace for slag removal.

[0162] 4. A measured amount of refined aluminum alloy molten material is poured into a casting cylinder for extrusion casting. The hydraulic press has a clamping force of 450 tons, a mold temperature of 200℃, and the pressure head moves at a speed of 0.4 m / s, pushing the aluminum alloy molten material through the gating system into the mold cavity. After filling, a high pressure of 300 MPa is applied and maintained for 40 seconds to allow the casting to solidify under high pressure, thus preventing shrinkage cavities. After the pressure holding period, the mold is opened, the casting is removed, and it is quickly placed in water at 60-100℃ for cooling.

[0163] 5. Place the hub casting into a 200℃ heat treatment furnace, keep it at that temperature for 8 hours, and then air cool it after removing it from the furnace.

[0164] 6. According to the technical requirements of the drawings, perform precision machining on the upper and lower end faces, outer surface and assembly surface of the hub body to obtain the final product.

[0165] The clutch hub prepared by the above method was tested for hardness, tensile strength, surface roughness and tooth profile accuracy. Its hardness was 165HBW, yield strength was 382MPa, tensile strength was 451MPa, elongation after fracture was 4.5%, tooth surface roughness Ra was 1.0μm and tooth profile accuracy was grade 8.

[0166] refer to Figure 2 This disclosure provides an extrusion casting mold for use in the clutch hub forming method of any of the foregoing embodiments. The extrusion casting mold includes: a cylinder seat 10, a fixed mold assembly 20, a moving mold assembly 30, a first mechanical locking mechanism 40, and a second mechanical locking mechanism 50. The cylinder seat 10 is provided with a material cylinder 11. The fixed mold assembly 20 is located on the upper side of the cylinder seat 10 and has a recess 23. The bottom of the recess 23 can communicate with the material cylinder 11 when the fixed mold assembly 20 and the cylinder seat 10 are closed.

[0167] The moving mold assembly 30 is located above the fixed mold assembly 20 and has a protrusion 33. The protrusion 33 can be inserted into the recess 23 when the moving mold assembly 30 and the fixed mold assembly 20 are closed to form a cavity. A first mechanical locking mechanism 40 is configured to lock the fixed mold assembly 20 and the material cylinder seat 10 when the fixed mold assembly 20 is closed. A second mechanical locking mechanism 50 is configured to lock the moving mold assembly 30 and the fixed mold assembly 20 when the moving mold assembly 30 and the fixed mold assembly 20 are closed.

[0168] By employing a first mechanical locking mechanism and a second mechanical locking mechanism for locking during mold closing, additional clamping force can be provided outside the hydraulic press, preventing the molten aluminum alloy from being squeezed out of the gap when subjected to a large extrusion pressure of 200-300 MPa.

[0169] exist Figure 2 In this configuration, the first mechanical locking mechanism 40 may include: a first locking block 41, a second locking block 42, and a first U-lock 43. The first locking block 41 is disposed on the outer wall of the material cylinder seat 10, the second locking block 42 is disposed on the outer wall of the fixed mold assembly 20, and the first U-lock 43 is used to lock the relative positions of the first locking block 41 and the second locking block 42.

[0170] The second mechanical locking mechanism 50 may include: a third locking block 51, a fourth locking block 52, and a second U-lock 53. The third locking block 51 is disposed on the outer wall of the fixed mold assembly 20, the fourth locking block 52 is disposed on the outer wall of the moving mold assembly 30, and the second U-lock 53 is used to lock the relative positions of the third locking block 51 and the fourth locking block 52.

[0171] As mentioned earlier, in some embodiments, the clutch hub includes a hub base HS and a cylindrical structure HT integrally formed with the hub base HS. The cylindrical structure HT has an internal spline IS, which includes a plurality of key teeth arranged circumferentially. Accordingly, in the extrusion casting mold, the inner wall of the recess 23 has an axial draft angle of 0.3°, the region of the protrusion 33 corresponding to the tooth tips of the plurality of key teeth has an axial draft angle of 0.5°, and the region of the protrusion 33 corresponding to the tooth flank surfaces of the plurality of key teeth has an axial draft angle of 0.3°. These draft angles ensure smooth demolding of the aluminum alloy casting of the clutch hub and enable the acquisition of a high-precision tooth surface.

[0172] In some embodiments, the extrusion casting mold further includes an ejector pin assembly 60. The ejector pin assembly 60 is located above the moving mold assembly 30 and has a plurality of ejector pins 61 that can pass through the moving mold assembly 30 and be used for demolding the solidified aluminum alloy casting. The solidified casting can be ejected from the cavity by means of the ejector pin assembly 60.

[0173] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0174] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A method for forming a clutch hub, comprising: Obtain aluminum alloy melt; Provide the extrusion casting mold for the clutch hub body, and fill the barrel (11) of the extrusion casting mold with the molten aluminum alloy. After the aluminum alloy melt has been filled into the mold, it is pressurized and held to form a solidified aluminum alloy casting. The solidified aluminum alloy casting is subjected to incomplete solution treatment. Aging treatment is performed on aluminum alloy castings that have undergone incomplete solution treatment. The outer surface and inner assembly surface of the aluminum alloy casting that has undergone aging treatment are precision machined to obtain the finished clutch hub body; The step of performing incomplete solution treatment on the aluminum alloy casting includes: The solidified aluminum alloy casting is removed from the extrusion casting mold and placed in water at 60-100°C to cool.

2. The clutch hub forming method according to claim 1, wherein, The pressurization and maintenance steps include: Apply pressure at 200-300 MPa and hold for 30-40 seconds.

3. The clutch hub forming method according to claim 2, wherein, The extrusion casting mold includes a moving mold assembly (30), a fixed mold assembly (20), a material cylinder seat (10), a first mechanical locking mechanism (40), and a second mechanical locking mechanism (50). The material cylinder (11) is disposed on the material cylinder seat (10). The fixed mold assembly (20) is located on the upper side of the material cylinder seat (10) and can be locked with the material cylinder seat (10) by the first mechanical locking mechanism (40). The moving mold assembly (30) is located on the upper side of the fixed mold assembly (20) and can move relative to the fixed mold assembly (20) to form a cavity communicating with the material cylinder (11). It can also be locked with the fixed mold assembly (20) by the second mechanical locking mechanism (50). The step of providing the extrusion casting mold for the clutch hub and filling the cylinder (11) of the extrusion casting mold with the molten aluminum alloy includes: The extrusion casting mold is preheated; The moving mold assembly (30) is moved upward relative to the fixed mold assembly (20), and the mold release agent is sprayed onto the parts of the moving mold assembly (30) and the fixed mold assembly (20) that are used to form the cavity, respectively. The moving mold assembly (30) is moved downward relative to the fixed mold assembly (20) and closes with the fixed mold assembly (20). Then, the moving mold assembly (30) and the fixed mold assembly (20) are locked by the second mechanical locking mechanism (50). The moving mold assembly (30) and the fixed mold assembly (20) of the mold closing mechanism are moved upward relative to the material cylinder seat (10), and the aluminum alloy melt is filled into the material cylinder (11). The moving mold assembly (30) and the fixed mold assembly (20) are moved downward relative to the material cylinder seat (10) and closed with the material cylinder seat (10). Then, the fixed mold assembly (20) is locked with the material cylinder seat (10) by the first mechanical locking mechanism (40). The aluminum alloy melt is filled into the cavity through the barrel (11) at a speed of 0.1~0.4m / s.

4. The clutch hub forming method according to claim 3, wherein, The step of preheating the extrusion casting mold includes: The extrusion casting mold is preheated to maintain its temperature at 160-220°C.

5. The clutch hub forming method according to claim 1, wherein, The steps for aging aluminum alloy castings that have undergone incomplete solution treatment include: The aluminum alloy castings that have undergone incomplete solution treatment are held in a heat treatment furnace at 170-200℃ for 5-8 hours, and then removed from the furnace and air-cooled.

6. The clutch hub forming method according to claim 1, wherein, The aluminum alloy melt has the following composition by mass percentage (wt%): Si: 7-9, Cu: 2-4, Mg: 0.4-0.8, Mn: 0.3-0.6, Fe: 0.1-0.4, Ni: 0.4-0.6, Sr: 0.1-0.3, with the remainder being Al and unavoidable impurities, and the total impurities ≤ 0.4%.

7. The clutch hub forming method according to claim 6, wherein, The steps to obtain molten aluminum alloy include: According to the composition of the aluminum alloy melt by mass percentage (wt%), weigh out the following: aluminum ingots, aluminum-silicon alloy, aluminum-copper alloy, aluminum-manganese alloy, aluminum-nickel alloy, magnesium ingots encased in aluminum-copper alloy, and aluminum-strontium alloy. Aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots encased in aluminum-copper alloys, and aluminum-strontium alloys are symmetrically taken in a melting furnace and smelted to obtain the aluminum alloy melt.

8. The clutch hub forming method according to claim 7, wherein, Before the step of melting and weighing the aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys, the process also includes: The weighed aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, and aluminum-nickel alloys are placed in a drying furnace and preheated at a temperature of 150-250°C.

9. The clutch hub forming method according to claim 7, wherein, The steps for smelting symmetrically selected aluminum ingots, aluminum-silicon alloys, aluminum-copper alloys, aluminum-manganese alloys, aluminum-nickel alloys, magnesium ingots encased in aluminum-copper alloys, and aluminum-strontium alloys in a smelting furnace include: Preheated aluminum ingots are added to a melting furnace and heated to 700-760°C to melt the aluminum ingots into molten aluminum. The aluminum-silicon alloy, the aluminum-copper alloy, the aluminum-manganese alloy, and the aluminum-nickel alloy are weighed and added to the molten aluminum in order of increasing melting point, so as to melt the aluminum-silicon alloy, the aluminum-copper alloy, the aluminum-manganese alloy, and the aluminum-nickel alloy. Add the weighed magnesium ingots encased in an aluminum-copper alloy and stir electromagnetically. A rotary degassing method is used to introduce nitrogen or inert gas into the bottom of the smelting furnace for degassing. Add the weighed aluminum-strontium alloy and perform a modification treatment; A slag remover is added to the smelting furnace to remove slag.

10. The clutch hub forming method according to claim 1, wherein, The clutch hub includes a hub base (HS) and a cylindrical structure (HT) integrally formed with the hub base (HS). The cylindrical structure (HT) has an internal spline (IS) and the internal spline (IS) includes a plurality of key teeth arranged circumferentially. The steps for finishing the outer surface and inner assembly surfaces of the aluminum alloy castings that have undergone aging treatment include: The aluminum alloy casting that has undergone aging treatment is precision machined on both axial end faces of the portion corresponding to the hub base (HS) and the outer peripheral surface and axial end face of the portion corresponding to the cylindrical structure (HT). Annular grooves for mounting friction plates are machined on the aluminum alloy castings that have undergone aging treatment, corresponding to the plurality of key teeth.

11. A clutch hub body, obtained by the clutch hub body forming method according to any one of claims 1 to 10.

12. The clutch hub according to claim 11, wherein, The clutch hub has a hardness ≥150HBW, yield strength ≥320MPa, tensile strength ≥400MPa, and elongation after fracture ≥4%.

13. The clutch hub according to claim 11, wherein, The clutch hub includes a hub base (HS) and a cylindrical structure (HT) integrally formed with the hub base (HS). The cylindrical structure (HT) has an internal spline (IS), which includes multiple key teeth arranged circumferentially. The surface roughness Ra of the multiple key teeth is ≤1.6μm, and the tooth profile accuracy is grade 7-8.

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