Method of manufacturing an integrated wheel

Abstract

The invention relates to a method (100) for producing a one-piece vehicle wheel (1), wherein the vehicle wheel (1) has a wheel disc segment (2) and a wheel rim segment (3), and wherein the method (100) comprises: providing (101) a one-piece preform (4) of a metal material, in particular a circular blank (4) of a metal material or a strip (4) of a metal material, wherein the metal material is specified by material quality and / or material thickness; forming a cylinder (5) from the provided one-piece preform (4) of a metal material, wherein the cylinder (5) comprises the wheel disc segment (2) and the wheel rim segment (3); profiling (103) the respective material thickness in different regions of the respective segment (2, 3) of the wheel disc segment (2) and / or the wheel rim segment (3) of the one-piece vehicle wheel (1) based on a cold forming method, in particular based on a spinning forming method.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a one-piece wheel. Furthermore, this invention also relates to a wheel and an apparatus for this purpose. Background Technology

[0002] Wheels are a crucial component in ensuring the safe and efficient operation of vehicles, especially those used in passenger cars and commercial vehicles. Wheel manufacturing typically employs established methods based on various technologies and taking into account requirements for weight, strength, durability, and manufacturing cost.

[0003] For example, one known method for manufacturing wheels is forging. In this process, aluminum or steel billets are pressed into the desired shape under high pressure. Forging is characterized by producing parts with high strength and load-bearing capacity. However, its disadvantages are high energy consumption and consequently high cost. Furthermore, so-called casting processes, particularly low-pressure casting, are commonly used to manufacture aluminum wheels. In this process, molten aluminum is poured into a mold and then cooled in a controlled manner. Complex geometries can be achieved using modern casting techniques. However, the casting process can produce porous structures that require additional post-processing or heat treatment to improve material properties. Finally, so-called spinning processes are commonly used to manufacture wheels for passenger cars and / or commercial vehicles. In this process, wheel blanks are machined while being rotated and subjected to applied forces to achieve the desired final shape and material thickness. This process is particularly useful for manufacturing high-load-bearing wheels.

[0004] Recent developments have demonstrated the possibility of using additive manufacturing methods, such as 3D printing, to create prototypes or special wheels. These methods are capable of producing highly complex geometries and enabling wheel personalization. However, additive manufacturing currently has very limited application in mass production due to its long production times and high costs.

[0005] The ETRTO standard (European Technical Organization for Tires and Rim) defines the technical specifications for tires and rims for passenger cars and commercial vehicles, particularly regarding their dimensions, tolerances, valve connections, and assembly requirements. The standard aims to ensure the interoperability and safety of tires and rims, regardless of their manufacturer. Specifically, the ETRTO standard specifies geometric parameters such as flange width, flange height, profile shape, and mounting angles, which are crucial for tire and rim compatibility. The ETRTO standard has an indirect but significant impact on the manufacturing methods of passenger car and commercial vehicle wheels. On the one hand, the prescribed specifications influence the structural requirements that must be considered when designing rims. On the other hand, these requirements influence the choice of manufacturing methods, such as in the forging, casting, or rolling of rims, because certain geometries and tolerances must be precisely maintained to ensure compliance with the standard.

[0006] Furthermore, advancements in wheel manufacturing technology have led to the development of innovative manufacturing methods that ensure compliance with ETRTO standards.

[0007] Despite the existence of standardization, existing technologies still provide room for innovation, particularly in improving manufacturing precision, material utilization, and adapting to specific application requirements (e.g., wheels for electric vehicles or special commercial vehicles). Such developments aim to meet standard requirements while achieving additional features, such as improved energy efficiency or enhanced load-bearing capacity.

[0008] Known steel wheels consist of a rim and a disc mounted on the rim. For example, in commercial vehicle wheels, the disc is pressed into the rim with a slight interference fit and then permanently joined by a circumferential (partially interrupted) weld. The disc is joined either in the transition area of ​​the rim (the so-called Ledge, the cylindrical transition area between the rim shoulder and the groove) or directly in the groove. To achieve this, the profiles of the rim and disc extend adjacent to each other in the axial direction from the outside of the wheel to the weld, resulting in increased material usage and a gap between them. This gap between the disc and rim profiles typically degrades the wheel's aerodynamic performance. Therefore, for aerodynamic optimization, some vehicle manufacturers use wheel covers, which fully cover the wheel to improve its aerodynamic performance.

[0009] There are also structural forms where the wheel disc and rim are connected in the outer shoulder area. However, these structural forms have obvious disadvantages, namely, due to the 5° or 15° shoulder slope, the fit between the two parts can only be produced at a high cost, and the material overlap here also leads to an increase in material usage and wheel weight.

[0010] The known manufacturing methods have drawbacks, namely, the challenges of further reducing weight, optimizing costs, and integrating new material technologies, which provides room for innovative approaches. Summary of the Invention

[0011] One object of the present invention is to overcome, at least in part, the disadvantages of the prior art described above. In particular, an object of the present invention is to provide an improved method for manufacturing wheels.

[0012] Invention disclosure

[0013] The subject of this invention is a method having the features of claim 1, a wheel having the features of claim 16, and an apparatus having the features of claim 17. Other features and details of the invention derive from their respective dependent claims, description, and drawings. Herein, the features and details described in conjunction with the method according to the invention also apply to the wheel according to the invention and the apparatus according to the invention, and vice versa; therefore, reference can always be made to the disclosure of this invention.

[0014] The subject of this invention is particularly a method for manufacturing a one-piece wheel, wherein the wheel has a disc section and a rim section, and the method includes:

[0015] - Provide integral preforms of metal materials, particularly round billets or strips of metal materials, wherein the metal material is specified by material quality and / or material thickness;

[0016] - A cylindrical component is formed from a single precast blank of the provided metal material, wherein the cylindrical component includes the disc section and the rim section;

[0017] - Based on cold forming methods, especially spin forming methods, the material thickness of the disc section and / or rim section of a one-piece wheel is profiled in different regions of each section.

[0018] The advantage of this is that by using a one-piece preform of metal material, which is then separately formed into the disc and rim segments of the one-piece wheel, the manufacturability of the one-piece wheel is significantly simplified and improved. Variable material thickness can be achieved by contouring the individual segments to meet desired and / or necessary requirements, such as those of ETRTO standards. Furthermore, this ensures the stability and strength of the wheel for safe operation.

[0019] Within the scope of this invention, if the diameter of the rim section corresponds to a specified diameter of the rim groove of the wheel after the cylindrical member is formed, and the method further includes the following steps, another advantage can be achieved:

[0020] - The transition area of ​​the wheel is finally shaped in the wheel manufacturing mold using a working medium.

[0021] The working medium acts on the tool's die under controlled pressure such that a transition area is formed based on a specified specification of the wheel profile. This transition area is designated as a region of the wheel, located between the hub mounting surface of the disc section and the outer rim shoulder of the rim section, preferably at the outer rim flange of the rim section.

[0022] This allows the unibody wheel to have a continuously extending profile in the transition area, satisfying both aerodynamic and functional requirements, as is required for passenger or commercial vehicles. Furthermore, this enables a high degree of flexibility in the shape design of the unibody wheel, as final molding costs are lower and adjustments are faster. Additionally, the final molding of the transition area is significantly improved through the use of the working medium, as the wheel profile in the transition area can be manufactured more precisely and quickly. Moreover, this has the advantage of allowing the transition area to be optimized through special surface design of the profile, thereby improving aerodynamics. Furthermore, it is advantageous that the flexibility and adaptability of the working medium allows for the manufacture of difficult and irregular geometries that are difficult or impossible to achieve using rigid tools.

[0023] Within the scope of this invention, the working medium should be understood as a medium used in the forming process to act on a workpiece, such as a metal preform or a cylindrical metal part, through pressure or other physical influence, and to shape it into a specific form, such as a wheel. In wheel manufacturing, particularly in the manufacturing of wheel discs and / or rim sections, the working medium can be used to form the material and ensure a uniform force distribution.

[0024] Typical working media can be oil, water, or an oil-water mixture. These media are used, for example, in so-called internal high-pressure forming (IHU). In IHU, or hydroforming, a liquid medium such as oil or water is forced into a pre-formed workpiece under very high pressure. This forces the material against the cavity walls (mold) and shapes the cavity profile.

[0025] Alternatively, an elastic medium, such as an elastomer or similar elastic plastic, can be used. This elastic medium acts on the material of the wheel to be manufactured according to the same principle as a liquid medium, and deforms it through controlled pressure.

[0026] This principle corresponds to the Guerin process, which uses a flexible rubber pad as the working medium to uniformly press material against a rigid mold during the pressing process. The rubber pad acts as an adaptive medium, conforming to the shape of the workpiece to apply uniform pressure to the material. For this reason, these technologies have been largely unused in rim manufacturing to date, as the industry demands more stringent strength and precision standards. Long-term expert assessments have shown that liquid or elastic forms of working media (such as those used in the IHU or Guerin processes) are not employed in rim manufacturing because rims must meet high structural requirements. Surprisingly, however, tests using the working media described in this invention have demonstrated significant advantages in terms of precision, safety, and efficiency (including cost-effectiveness) in this innovative manufacturing method.

[0027] It can be envisioned that the metal preform comprises a seamless tube of metal material. This tube can then be cut accordingly to fit the wheel to be manufactured, and thus essentially constitutes the preform.

[0028] Then, during wheel manufacturing, the outer diameter, wall thickness, and length of the tube are selected to meet the basic requirements of the finished wheel. In this step, the cross-section of the tube can also be adjusted, for example, by generating the desired contours for the wheel rim and disc segments. The tube can also be further shaped, for example, by rotational forming or rolling. Depending on the wheel design, complex patterns can be created by laser cutting, especially in lightweight applications. Based on an internal high-pressure forming process, the tube can be placed in a mold, and the material is pressed against the cavity wall using a liquid acting medium to form the wheel rim and disc segments. This method is particularly suitable for manufacturing one-piece, seamless wheels. Alternatively, the disc segment can be produced, for example, by spin forming, where material can be pulled from the tube and evenly distributed. This allows for precise control of material thickness and increases material strength through cold work hardening. Other advantages of this method are that the finished wheel does not contain welds or connection points, which improves the structural integrity and strength of the wheel, and the diverse tubular preforms offer high versatility, allowing for flexible adjustments to meet different design requirements and application scenarios.

[0029] It can be further envisioned that a portion of the method of the present invention is based on hot forming, which can be combined with other forming methods. Furthermore, it is specified that this type of forming is performed above the respective recrystallization temperature of the metals used. Hot forming is advantageously suited for components that must withstand high loads, such as wheels. Examples of hot forming methods include forging, hot rolling, or deformation heat treatment.

[0030] The recrystallization temperature can be described as the temperature at which a metal completely recrystallizes within a specific observation period. It is typically estimated, using empirical rules, to be 40% or 50% of the absolute melting temperature of the metal. Recrystallization is a technical term in metallurgy and crystallography, referring to the process by which changes in the microstructure induced by nucleation and grain growth reduce lattice defects within the grains. This process is accompanied by a decrease in strength and usually produces a grain refinement effect. A prerequisite is the introduction of dislocations through forming processes, which can act as nuclei for new grain formation. When the forming process is carried out above the recrystallization temperature, dynamic recrystallization of the corresponding metal can be observed.

[0031] Alternatively, it can be envisioned that the method further includes, prior to the final shaping of the transition region:

[0032] - The cylindrical part is placed into a tool for further final shaping of the various sections of the wheel, wherein the tool is horizontally or vertically split, and wherein each split tool is provided as a female mold for final shaping of the transition area.

[0033] This simplifies the handling of cylindrical parts due to their cylindrical or rotationally symmetric geometry, such as that of a wheel, which allows the blank to be held in its natural horizontal orientation. The split structure enables precise centering and forming of the wheel. Furthermore, the horizontal split structure of the tool allows for a more compact machine design, saving production space.

[0034] The vertical split structure facilitates precise alignment of the workpiece, which is especially important for rotationally symmetrical components (such as wheel rims) to avoid imbalance.

[0035] Furthermore, the advantage of vertical split-type tools lies in their greater adaptability to multi-level production line layouts, as they allow for dual-sided operating channels. For large and heavy workpieces, vertical positioning can utilize gravity assistance to achieve more convenient handling operations.

[0036] Within the scope of this invention, if, during the forming of the transition region in a vertical split tool, the working medium is squeezed horizontally from both sides according to controlled pressure, causing the transition region of the cylindrical part to be pressed against the female mold of the vertical split tool, and the method further includes at least one of the following steps, then another advantage can be achieved:

[0037] - The follow-up feed medium supports the final shaping of the transition region;

[0038] - Support the open end of the rim section to prevent the rim section from buckling or bulging.

[0039] In this way, the method for manufacturing one-piece wheels allows for precise control over the final forming of the transition area, ensuring that this area is pressed and formed by the expansion of the working medium into the female mold of the vertical split tool. Precise control over the final forming of the transition area can be achieved by following the feeding of the working medium and supporting the open end of the rim section, thus preventing buckling or bulging of the rim section of the cylindrical part. Follow-up feeding refers to the controlled directional conveying or movement of the working medium, components, or materials continuously or gradually adjusted by one or more mechanisms according to set process parameters (such as pressure). This control can be achieved individually or in combination by hydraulic, pneumatic, mechanical, electromagnetic, thermal, or software-based means. Follow-up feeding or controlled directional conveying does not require that the components be physically fixed to the conveying mechanism, and also includes guiding the working medium along a predetermined path by intentionally designing a pressure gradient.

[0040] According to the present invention, any method comprising the following steps constitutes a follow-up feeding of the working medium within the scope of the claims, particularly a directional feeding of the working medium: (i) injecting the working medium into the transition region; (ii) applying a directional force (such as pressure, flow rate, heat, sound waves or electromagnetic fields); and (iii) adjusting the force in real time using at least one feedback element.

[0041] According to another possibility, the method may also include, when finally shaping the transition area in a horizontally split tool, the following:

[0042] - Fill the cylindrical component with the working medium;

[0043] - The cylindrical part is sealed at the open end of the rim section using a sealing device;

[0044] - A controlled pressure is applied to the working medium using a pressure device, so that the working medium is pressed toward the transition area and the area is pressed into the female mold of the horizontal split tool;

[0045] - The sealing device is dynamically controlled based on the diffusion of the working medium through the controlled pressure.

[0046] In this way, the method of manufacturing a one-piece wheel allows for precise control over the final shaping of the transition area, ensuring that this area is pressed against the female mold of the horizontally split tool. Precise control over the final shaping of the transition area is achieved through a follow-up control sealing device. Using a liquid or elastic action medium to form the wheel ensures a uniform pressure distribution of the action medium in the transition area and / or conserves material in the transition area.

[0047] Furthermore, the follow-up control of the sealing device (especially the sealing cylinder) enables it to track the contour of the hub edge, that is, to establish and maintain the pressure of the working medium through the follow-up movement of the sealing device.

[0048] The follow-up control of the sealing device described herein refers to the controlled positioning, displacement, or driving of the sealing device in a manner dynamically correlated with the spatial expansion of the working medium—this spatial expansion itself is achieved by applying controllable pressure to the medium. Such follow-up control can be implemented through pressure, heat, or electromagnetic effects. According to the present invention, any method comprising the following steps falls within the scope of follow-up control of the sealing device: (i) detecting the spatial propulsion state of the working medium; (ii) applying controlled pressure to the medium; and (iii) driving the sealing device in a manner functionally dependent on the detected propulsion state. This functional dependency can be linear, nonlinear, piecewise, or event-triggered, and the driving method can be continuous or discrete.

[0049] It is further advantageous that the action medium may be specified to be in liquid form and / or elastic form, wherein the liquid form is preferably water, and / or the elastic form is preferably elastic plastic, particularly an elastomer.

[0050] This allows liquid media (such as oil or water) to uniformly distribute pressure across the entire surface of the workpiece, unaffected by tool geometry. This effectively reduces the risk of localized deformation, cracking, or material failure in the manufactured wheels. Based on this characteristic, this solution can employ processes such as internal high-pressure forming to achieve precise deformation of the wheels. Furthermore, in fluid-based forming processes (such as internal high-pressure forming), the material is pressed against the existing cavity wall that serves as the mold, meaning that the structure of the required tools can be simplified.

[0051] In the case of an elastic medium, such as an elastomer, it flexibly adapts to complex geometries and uniformly presses the material against the mold. This advantageously minimizes stress in the wheel material. Furthermore, the mold (forming tool) only needs to be manufactured from one side, as the elastic medium applies pressure from the other side. This advantageously and significantly reduces tooling costs. Therefore, using a liquid or elastic medium to form wheels offers advantages such as uniform pressure distribution, material savings, the possibility of manufacturing complex geometries, and reduced tooling costs.

[0052] It can also be envisioned that the diameter in the transition region between the wheel disc segment and the rim segment substantially corresponds to the specified final diameter of the wheel disc segment, and the method further includes:

[0053] - A transition region is finally formed based on the spinning method, wherein the transition region is arranged between the hub mounting surface of the wheel disc section and the outer rim shoulder of the rim section, preferably at the outer rim flange of the rim section.

[0054] The advantage of this is that the transition area can be flexibly adjusted in terms of material thickness and design. Furthermore, this allows the unibody wheel to have a continuously extending profile in the transition area that meets both aerodynamic and functional requirements, as is required for passenger cars or commercial vehicles.

[0055] For example, the method may be specified to also include:

[0056] - Place the cylindrical part into a tool containing a first mold and a second mold;

[0057] - The diameter of the rim section is reduced by using a second mold.

[0058] This allows for the supply of the desired shape of the rim section to be manufactured to meet predetermined standard requirements. Furthermore, the rim diameter required for, for example, passenger cars or commercial vehicles can be advantageously provided during this process.

[0059] The mold used for rim manufacturing is generally understood as a robust, precision-manufactured, high-strength steel tool. It has a hollow cylindrical shape, with its inner contour precisely corresponding to the required shape of the rim. The mold surface is smooth and polished to ensure high surface quality of the produced rims.

[0060] Furthermore, it is advantageous if the contour machining of the wheel disc section and / or rim section is performed based on a combination of external high-pressure forming and spinning forming methods.

[0061] In external high-pressure forming (AHU), the disc segment and / or rim segment are formed or finalized to create a continuous, extended profile for the wheel. AHU is already used in the automotive industry for body parts, particularly where precise external profiles are required to meet aerodynamic or aesthetic requirements. It can be used alone or in combination with other methods to effectively finalize specific areas of the disc segment and / or rim segment when manufacturing unibody wheels.

[0062] It can also be envisioned that the method includes:

[0063] - A stretching process is applied to the preform, particularly a strip of metal, to reduce the thickness of the preform material in sections and thereby increase the width of the preform, particularly the strip of metal, thereby strengthening specific portions of the rim section, preferably the inner and / or outer rim flanges;

[0064] - The spun forming method is used to profile the stretched material of the rim section to form the required material quality and final shape of the rim section profile.

[0065] Stretching allows metal preforms (such as steel strips) to be stretched into desired shapes or sizes by mechanical force. This advantageously and positively affects the material properties and geometry of the preform.

[0066] Furthermore, within the scope of this invention, it may be advantageous if the method further includes at least one of the following steps:

[0067] - Cut at least one opening in the region of the wheel section by means of stamping, laser cutting, plasma or water jet cutting;

[0068] - At least three openings are cut into the region of the wheel segment by means of stamping, laser cutting, plasma or water jet cutting, wherein each opening has the same shape, and / or wherein the at least three openings are arranged at equal distances from each other in the region of the wheel segment.

[0069] Taking stamping as an example, this technology enables the mechanical cutting of openings from the material using a punch and die. Wheel disc sections processed using this method have the significant advantage of clean and precise cut edges. Furthermore, this process can be efficiently integrated into production lines that include other forming processes. When forming wheel disc sections (such as deep drawing or spinning), the opening operation can be completed simultaneously using pre-set embossing or punching tools, thereby reducing the number of independent processing steps. Similarly, efficient and precise opening processing can be achieved using laser cutting, plasma cutting, or waterjet cutting technologies, which is particularly advantageous for manufacturing wheel designs with complex structures or fine textures. These advanced processes also have the advantage of reducing the load stress on the wheel material, thus effectively preventing cracks and deformation.

[0070] Within the scope of this invention, it is also conceivable that the method may further include:

[0071] - The wheel disc section, especially the transition area and the hub mounting surface, is contoured to provide an outer, closed profile.

[0072] This ensures that the profile of the wheel disc section guarantees favorable aerodynamic characteristics for the corresponding individual wheel arch. Furthermore, the profile of the wheel from the hub mounting surface to the outer rim flange allows for material savings, which positively impacts the product's CO2 footprint.

[0073] If, within the scope of this invention, the method further includes the following steps, it may be advantageous:

[0074] - The wheel disc section, especially the transition area, is contoured so that the transition element in the transition area has an axial direction from the outside to the inside, from the inside to the outside, or substantially perpendicular to the wheel's central axis relative to the wheel's central axis.

[0075] The advantage of this manufacturing principle is that wheels produced based on this principle can flexibly adapt to different vehicle models (provided they have the appropriate wheel offset). Offset refers to the axial distance between the inner mounting surface of the wheel and the center line of the rim profile. This characteristic allows for the manufacture of customized wheels with corresponding wheel disc transition element orientations for various vehicles such as passenger cars, commercial trucks, heavy-duty trucks, and trailers.

[0076] It can also be envisioned that the method includes:

[0077] - The diameter of the rim section is calibrated according to the material quality.

[0078] This ensures uniform and precise adherence to the predetermined diameter. Furthermore, it minimizes deviations and ensures optimal wheel fit. Additionally, it allows the calibration process to smooth out minor surface irregularities that may occur in the rim section area during manufacturing.

[0079] According to another possibility, it can be stipulated that after the cylindrical component is formed, the diameter of the rim section corresponds to the specified diameter of the rim groove of the wheel, and

[0080] The contour processing further includes:

[0081] - The transition area between the wheel disc section and the rim section is finalized using rotating contour rollers.

[0082] After the transition area is finally formed, the disc segment has a circular geometry.

[0083] The advantages of this technical solution are as follows: the one-piece wheel has a continuously extending contour in the transition area. This contour design meets both aerodynamic requirements and the functional needs of the wheel—just as the standards required for passenger cars and commercial vehicles. Furthermore, using contour rollers to form the transition area further improves process quality, as this method can process the contour of the wheel's transition area faster and more accurately. In addition, by specially designing the contour surface, aerodynamic optimization of the transition area can be achieved, thereby effectively improving the overall aerodynamic performance of the vehicle.

[0084] It can be further specified that the contour machining of the rim section also includes at least one of the following steps:

[0085] - Further contouring steps are performed using rotating contour rollers to provide a tapered end on the open side of the cylindrical part;

[0086] - Multiple further contouring steps are performed using rotating contour rollers, so that the material of the rim section flows only from the open side of the cylindrical part toward the transition area during the multiple contouring steps, in order to reshape the predetermined rim profile.

[0087] This technical solution enables the fabrication of rim segments with the required shape and material quality, thereby meeting established standard requirements. Furthermore, this process can flexibly produce specific rim diameters suitable for different vehicle models, such as passenger cars or commercial vehicles. Particularly advantageous is that the desired rim profile can be decomposed into one or more profile forming steps, thereby achieving uniform deformation during the implementation of the method of this invention—the process only allows unidirectional flow of rim material from the open side of the cylindrical component. Thus, in multi-stage profile processing, the first profile step can complete the forming of the transition area between the disc segment and the rim segment, while in subsequent profile processing of the rim segment, the disc segment can be essentially decoupled from such subsequent steps.

[0088] The subject matter of this invention also relates to a vehicle wheel, particularly suitable for passenger cars or commercial vehicles, manufactured according to the method of the invention. Therefore, the wheel according to the invention possesses the same technical advantages as those described in detail with reference to the method of the invention.

[0089] The subject matter of this invention also relates to an apparatus for manufacturing wheels, comprising corresponding components configured to perform the method of the invention. Thus, it is evident that the apparatus according to the invention also possesses all the technical advantages described in detail with reference to the method of the invention. Attached Figure Description

[0090] Other advantages, features, and details of the invention will become apparent from the following description, in which embodiments of the invention are described in detail with reference to the accompanying drawings. Technical features mentioned in the claims and specification, whether alone or in any combination, constitute the essence of the invention. In the drawings:

[0091] Figure 1 A schematic visualization of a method according to an embodiment of the present invention is shown.

[0092] Figure 2 A schematic representation of a process according to an embodiment of the present invention is shown.

[0093] Figure 3 Another illustrative representation of a portion of the process according to an embodiment of the present invention is shown.

[0094] Figure 4 Another illustrative representation of a portion of the process according to an embodiment of the present invention is shown.

[0095] Figure 5 Another illustrative representation of a portion of the process according to an embodiment of the present invention is shown, and

[0096] Figure 6 A schematic representation of a wheel according to an embodiment of the present invention is shown.

[0097] In the following figures, the same reference numerals are used for the same technical features, even if they come from different embodiments.

[0098] List of reference numerals

[0099] 1. Wheel

[0100] 2-wheel section

[0101] 3. Wheel rim section

[0102] 4. Precast billets, round billets, and strips

[0103] 5. Cylindrical components

[0104] 6. Working medium

[0105] 10. Wheel hub mounting surface

[0106] 11 Transition Components

[0107] 12. Outer rim flange

[0108] 13. Internal rim flange

[0109] 14. Outer rim shoulder

[0110] 15. Inner rim shoulder

[0111] 16. Rim groove

[0112] 40 Transition Zone

[0113] 50 tools, vertical split structure

[0114] 51. Lower part of the tool

[0115] 52 Support ring

[0116] 53 Mold

[0117] 54 Another mold, another tool

[0118] 60 tools, horizontal split structure

[0119] 61 upper mold

[0120] 62 Lower mold

[0121] 63 Sealing device, sealing cylinder

[0122] 70 Manufacturing Equipment

[0123] 100 methods

[0124] 101 provides

[0125] 102 Formation

[0126] 103 Contour Machining Detailed Implementation

[0127] Figure 1 A schematic visualization of a method according to an embodiment of the present invention is shown. In particular, Figure 1 A method 100 for manufacturing a one-piece wheel 1 is shown, wherein the wheel 1 has a disc segment 2 and a rim segment 3. The method 100 includes: in step 101, providing a one-piece preform 4 of metal material, particularly a circular blank 4 of metal material or a strip 4 of metal material, wherein the metal material is specified by material mass and / or material thickness. In step 102, forming a cylindrical part 5 from the provided one-piece preform 4 of metal material, wherein the cylindrical part 5 includes the disc segment 2 and the rim segment 3. In step 103, contouring the respective material thicknesses of the disc segment 2 and / or the rim segment 3 of the one-piece wheel 1 in different regions of the respective segments 2, 3, based on a cold forming method, particularly based on a spin forming method.

[0128] also, Figure 1 An apparatus 70 for manufacturing a one-piece wheel 1 is shown, comprising components, particularly tools 50 and 60, which are configured to perform the method 100 of the present invention.

[0129] Figure 2 A schematic representation of a process according to an embodiment of the present invention is shown. In particular, Figure 2 An exemplary process flow for manufacturing a one-piece wheel is illustrated. The manufacturing of the one-piece wheel 1 involves a multi-stage process, which includes various technologies and procedures to achieve the final shape and structure of the wheel 1. An exemplary process flow is described in detail below:

[0130] Step 201 may include, for example, unwinding a metal strip or bar from a provided metal coil. The metal may be, for example, any type of high-quality steel alloy or aluminum. After unwinding in step 201, the strip may be further processed or adjusted according to further steps 202, 203, wherein the adjustment may include straightening the strip, for example, straightening the surface and removing burrs from the edges of the metal strip. Subsequently, in step 204, the thus processed metal strip is cut to the desired length, corresponding to the rim size to be produced. The cut material (i.e., the cut strip, particularly steel strip) is bent into a circular or cylindrical shape in step 205 to form a one-piece preform for the wheel to be manufactured. In step 206, the ends of the thus bent steel strip may be welded together at the flat ends to form a closed loop. After welding, the rim surface is smoothed in step 207 to remove irregularities, such as weld seams. For the stretching process, in step 208, the circularly bent steel strip is placed between stretching tools. For the stretching process, special tools (e.g., calendering rolls) are used, configured to locally and specifically reduce the thickness of the steel strip. The material displaced by the calendering rolls causes the strip to increase in width in the axial direction. Through the flow forming process in step 209, the rim material is further segmented and deformed under pressure, thereby increasing strength and reducing weight. Furthermore, in this step, the desired diameter of the rim 2 is provided such that it corresponds to the predetermined rim groove diameter of the wheel 1. A shape is produced in this process, specifically the so-called cylindrical member 5, which has an open side.

[0131] The next processing step 210 includes a contouring and calibration process, wherein the rim contour of the rim 2 is progressively segmented or partially formed through multiple (e.g., up to three) processing steps to achieve the final contour. The contouring performed during processing step 210 (which may include multiple contouring steps) may also include final shaping 210a of the transition region 40 between the wheel disc 2 or wheel disc segment 2 and the rim 3 or rim segment 3 using a rotating contouring roller, wherein after the transition region 40 is finalized, the wheel disc segment 2 has a circular geometry. For example, the contouring of the rim segment 3 in step 210 may further include at least one of the following steps 210b, 210c:

[0132] - Perform a further contouring step 210b, using a rotating contouring roller to provide a tapered end on the open side of the cylindrical part;

[0133] - Perform multiple further contouring steps 210c, using rotating contouring rollers, so that the material of the rim section flows only from the opening side of the cylindrical part to the transition area during the multiple contouring steps, in order to reshape the predetermined rim profile.

[0134] The transition region 40 includes, for example, transition element 11, outer rim flange 12 of wheel 1, and outer rim shoulder 14. In other words, each element 11, 12, and 14 of the transition region 40 is ultimately formed through the contour machining step of the above-described machining step 210.

[0135] Then, in step 211, holes for the valve stem can be punched in rim section 3. Finally, the dimensions of the completed rim section 3 (not shown) can be checked.

[0136] Figure 3 A schematic representation of a portion of the process according to an embodiment of the present invention is shown. In particular, Figure 3 A portion of the wheel 1 manufacturing process is shown, demonstrating the final shaping of the cylindrical part 5 using the working medium 6 in a vertical split tool 50. Figure 4 The left half shows the time stages before final shaping. Figure 4 The right half shows the time stage after the final shaping of the wheel 1 transition area 40.

[0137] The cylindrical component 5 can be placed in the tool 50 for further final shaping of the various segments 2, 3 or the cylindrical component 5 of the wheel 1, and is adjacent to the mold 53 above. The mold 53 forms the female mold of the desired wheel 1. The transition region 40 can here be designated as a region of the wheel, which is arranged between the hub mounting surface of the disc segment 2 and the outer rim shoulder, preferably the outer rim flange 12, of the rim segment 3 to form an integral, continuously extending profile of the wheel 1. That is, for example, a mold with a split tool 50 is provided as a female mold for the final shaping of the transition region.

[0138] like Figure 3 As shown, the diameter of the rim section 3 of the cylindrical component 5 can correspond to the specified diameter of the rim groove 16 of the wheel 1 (see also...). Figure 6 During the final forming of the transition region 40, the action medium 6 is pressed into the tool's female mold 53 in the tool 50 by controlled pressure, so that the transition region 40 is formed based on the specified specifications of the wheel 1 profile, thereby forming an integral, continuously extending profile of the wheel 1.

[0139] Furthermore, during the final shaping of the transition region 40 in the vertical split tool 50, the actuating medium 6 is squeezed horizontally from both sides under controlled pressure, causing the transition region 40 of the cylindrical part 5 to be pressed against the female mold of the mold 53. Optionally, a follow-up feed actuating medium 6 can be specified to support the final shaping of the transition region 40. Additionally, for example, support can be provided for the open end of the rim section 3 or the cylindrical part 5 to prevent buckling or bulging of the rim section 3 or the cylindrical part 5.

[0140] Figure 4 Another illustrative representation of a portion of the process according to an embodiment of the present invention is shown. In particular, Figure 4 A portion of the manufacturing process of wheel 1 is shown, demonstrating the final shaping of cylindrical part 5 in a horizontal split tool 50 using working medium 6. Figure 4 The upper part shows the time stages before final shaping. Figure 4 The lower half shows the time stage after the final forming of the wheel 1 transition area 40.

[0141] The cylindrical part 5 placed in the horizontal split tool 60 can be filled with an action medium 6, such as liquid form 6 or liquid medium 6, for final shaping. The liquid action medium 6 can be a liquid such as water or oil. Then, the cylindrical part 5 can be closed at its open end (rim section 3) by a sealing device 63 (e.g., a sealing cylinder 63). By applying controlled pressure to the action medium 6, and by means of a pressure device acting on the sealing device 63, the liquid 6 as the action medium can be forced towards the transition region 40, thereby pressing the region 40 into the female molds of the upper and lower molds 61, 62 to form the transition region 40, for example in Figure 4The lower half is shown. The sealing device 63 is dynamically controlled according to the diffusion of the working medium 6 on the working medium 6 by the controlled pressure, so that the precise final forming process of the transition region 40 can be achieved.

[0142] Figure 5 Another illustrative representation of a portion of the process according to an embodiment of the present invention is shown. In particular, Figure 5 A portion of the wheel 1 manufacturing process is shown, demonstrating the thinning of the rim section 3 of the cylindrical part 5 in a horizontal split tool 50. Figure 5 The left half of the diagram exemplarily illustrates the time phase before the diameter of rim segment 3 is reduced or before it becomes thinner. Figure 5 The right half shows the time phase after the transition area 40 of wheel 1 becomes thinner.

[0143] When machining the cylindrical part 5, it can be specified, for example, that the diameter of the transition area between the disc section 2 and the rim section 3 substantially corresponds to the specified final diameter of the disc section 2, such as... Figure 5 The left half is shown.

[0144] The final forming of the transition region 40 can be, for example, based on a spinning method, wherein the transition region 40 is arranged between the hub mounting surface 10 of the disc section 2 and the outer rim shoulder 14, preferably the outer rim flange 12, of the rim section 3 to form an integral, continuously extending profile of the wheel.

[0145] For example, the cylindrical part 5 can be first placed into the mold 54 of the vertical split tool 50. Then, the rim section 3 (and / or disc section 2) can be formed, for example, using the respective mold 54 or alternatively using another tool 54, such that the diameter of the rim section 3 is reduced or thinned.

[0146] Figure 6 A schematic sketch of a wheel profile according to an embodiment of the present invention is shown. Figure 6 A schematic cross-section of a wheel 6 according to the invention is shown, for example for passenger cars, commercial vehicles such as urban delivery vehicles or vans, or for trailers. The wheel 1 includes a disc section 2 and a rim section 3. A transition region 40 is arranged between the hub mounting surface 10 of the disc section 2 and the outer rim shoulder 14 of the rim section 3, preferably the outer rim flange 12 of the rim section. Figure 6 As shown, the transition region 40 includes a transition element 11, an outer rim flange 12, and an outer rim shoulder 14.

[0147] Wheel disc segment 2 includes a hub mounting surface 10 and a transition element 11 for connecting wheel 1 to a vehicle hub (hub not shown), wherein the transition element is arranged between the hub mounting surface 10 and the outer rim flange 12. A transition region 40 includes the area between the hub mounting surface 10 and the outer rim shoulder 14, i.e., this region 40 includes, for example, the transition element 11 and the outer rim flange 12 and the outer rim shoulder 14. The transition element 11 of wheel disc segment 2 is directly arranged on or integrally connected to the outer rim flange 12 of rim segment 3. Figure 6 The transition element 11 is shown in an axial direction from the outside to the inside relative to the central axis of the wheel 1. Figure 6 The rim profile shown is applicable to passenger vehicles. Alternatively, the transition element 11 may be specified in other directions relative to the wheel's central axis, such as axially from the inside out or substantially perpendicular to the central axis of the wheel 1. The transition element 11 and the outer rim flange 12 are formed as a seamless circumferential segment of material for the wheel 1.

[0148] The rim segment 3 can be designed, for example, as a deep-groove rim 3, which can be formed, for example, as a 5° or 15° sloping shoulder rim. Furthermore, the rim segment 3 can be symmetrical. The profile of the rim segment 3 can include different parts. According to... Figure 6 In one embodiment, the rim segment 3 includes an outer and an inner rim flange 12, 13, an outer rim shoulder 14, and an inner rim shoulder 15. A deep groove 16 is formed between the two rim shoulders 14, 15, the deep groove including its bottom. Optionally, a so-called hump may be arranged between the rim shoulders 14, 15 and the deep groove 16.

[0149] In addition, the transition element 11 may have a notch for the valve passage or include a vent.

[0150] The foregoing explanation of the embodiments is merely an example to describe the present invention. Of course, features of the various embodiments can be freely combined with each other as long as they are technically meaningful, without departing from the scope of the present invention.

[0151] Cross-references to related applications

[0152] This application claims priority to German patent application filed on November 28, 2024 (previous application number: 10 2024 135329.5). All disclosures of the aforementioned application are incorporated herein by reference.

Claims

1. A method (100) for manufacturing an integral wheel (1), wherein, The wheel (1) has a disc section (2) and a rim section (3), and the method (100) includes: - Provide (101) an integral preform (4) of metal material, particularly a circular billet (4) of metal material or a strip (4) of metal material, wherein the metal material is specified by material mass and / or material thickness; - A cylindrical part (5) is formed (102) from a one-piece preform (4) of the provided metal material, wherein the cylindrical part (5) includes the wheel disc section (2) and the wheel rim section (3). - Based on cold forming methods, especially based on spinning forming methods, the material thickness of the disc segment (2) and / or the rim segment (3) of the integral wheel (1) in different regions of each segment (2, 3) is profiled (103).

2. The method (100) according to claim 1. in, After forming the cylindrical member (5) as described in (102), the diameter of the rim section (3) corresponds to the specified diameter of the rim groove (16) of the wheel (1), and The method (100) further includes: - Using the working medium (6), the transition area (40) of the wheel (1) is finally shaped in the tools (50, 60) used to manufacture the wheel (1). The working medium (6) acts on the female mold of the tool (50, 60) under controlled pressure such that the transition area (40) is formed according to the specified specifications of the contour of the wheel (1). The transition area (40) is designated as a region of the wheel (1) between the hub mounting surface (10) of the disc section (2) and the outer rim shoulder (14) of the rim section (3).

3. The method (100) according to claim 2. in, The method (100) further includes the following steps before the transition region (40) is finally formed: - The cylindrical component (5) is placed into the tools (50, 60) for further final shaping of the various segments (2, 3) of the wheel (1). The tools (50, 60) are horizontally or vertically split, and each split tool (50, 60) is provided as a female mold for the final shaping of the transition area (40).

4. The method (100) according to claim 3. in, When the transition region (40) is finally formed in the vertical split tool (50), the action medium (6) is squeezed from both sides in the horizontal direction according to the controlled pressure, so that the transition region (40) of the cylindrical part (5) is pressed against the female mold of the vertical split tool (50), and the method (100) further includes at least one of the following steps: - The working medium (6) is fed in a follow-up manner to support the final shaping of the transition region (40); - Support the open end of the rim section (3) to prevent the rim section (3) from buckling or bulging.

5. The method (100) according to claims 2 and 3. in, The method (100) further includes, when finally shaping the transition region (40) in the horizontal split tool (60): - Fill the cylindrical component (5) with the working medium (6); - The cylindrical part (5) is closed at the open end of the rim section (3) by means of a sealing device (63); - A controlled pressure is applied to the working medium (6) by means of a pressure device, so that the working medium (6) presses against the transition region (40) and presses the region (40) into the female mold of the horizontal split tool (60); - The sealing device (63) is controlled according to the diffusion of the working medium (6) on the working medium (6) by the controlled pressure.

6. The method (100) according to any one of claims 2 to 5. in, The working medium (6) has a liquid form and / or an elastic form, wherein the liquid form is preferably water, and / or the elastic form is preferably an elastic plastic, particularly an elastomer.

7. The method (100) according to claim 1. in, The diameter in the transition region (11) between the wheel disc section (2) and the rim section (3) substantially corresponds to the specified final diameter of the wheel disc section (2), and The method (100) further includes: - The final forming of the transition region (40) is based on the spinning forming method, wherein the transition region (40) is arranged between the hub mounting surface (10) of the wheel disc section (2) and the outer rim shoulder (14) of the rim section (3).

8. The method (100) according to any one of the preceding claims. in, The method (100) further includes: - The cylindrical part (5) is placed into a tool (50), which includes a first mold (53) and a second mold (54); - The diameter of the rim section (3) is reduced by means of the second mold (54).

9. The method (100) according to any one of the preceding claims. in, The contour processing (103) of the wheel disc segment (2) and / or the rim segment (3) is performed based on a combination of external high pressure forming and spinning forming methods.

10. The method (100) according to any one of the preceding claims. in, The method (100) further includes: - A stretching process is applied to the preform (4), particularly the metal strip (4), to reduce the thickness of the material of the preform (4) in segments and thereby increase the width of the preform (4), particularly the metal strip (4), thereby strengthening a specific portion of the rim section (3), preferably the inner and / or outer rim flanges (12, 13). - The spun forming method is used to profile the stretched material of the rim segment (3) to form the material quality and final shape required for the profile of the rim segment (3).

11. The method (100) according to any one of the preceding claims. in, The method (100) further includes at least one of the following steps: - Cut at least one opening in the region of the wheel section (2) by stamping, laser cutting, plasma or water jet cutting methods; - At least three openings are cut in the region of the wheel segment (2) by stamping, laser cutting, plasma or water jet cutting, wherein each opening has the same shape, and / or wherein the at least three openings are arranged at equal distances from each other in the region of the wheel segment (2).

12. The method (100) according to any one of the preceding claims. in, The method (100) further includes at least one of the following steps: - The wheel disc segment (2), particularly the transition area (40) and the hub mounting surface (10) are contoured to provide an outer, closed contour orientation; - The wheel section (2), particularly the transition region (40), is contoured such that the transition element (11) of the transition region (40) has an axial direction from the outside to the inside, an axial direction from the inside to the outside, or substantially perpendicular to the central axis of the wheel (1) relative to the central axis of the wheel (1).

13. The method (100) according to claim 1. in, After forming (102) the cylindrical member (5), the diameter of the rim section (3) corresponds to the specified diameter of the rim groove (16) of the wheel (1), and wherein the method (100) further includes: - The transition area (40) between the disc section (2) and the rim section (3) of the wheel (1) is finally shaped by means of a rotating contour roller. During and after the final forming of the transition region (40), the disc segment (2) has a circular geometry.

14. The method (100) according to claim 13. in, The contour machining of the rim section (103) also includes at least one of the following steps: - Perform further contouring steps, using rotating contouring rollers to provide a tapered end on the open side of the cylindrical part; - Perform multiple further contouring steps using the rotating contouring rollers, such that the material of the rim segment flows only from the open side of the cylindrical member toward the transition region during the multiple contouring steps, to reshape the predetermined rim profile.

15. An apparatus (70) for manufacturing wheels, wherein, The apparatus (70) includes components configured to perform the method according to any one of claims 1 to 14.

Images