Non-pneumatic tire having metal spokes formed by thermomechanical control process

Abstract

A method of manufacturing a spoke for a non-pneumatic tire, the method comprising: providing a steel plate; heating the steel sheet to a temperature of at least 1000 DEG C; and rolling the steel sheet at a temperature of at least 900 DEG C until the thickness of the steel sheet has reduced by at least 80%. The method further includes first quenching the steel sheet and reheating the steel sheet. The method further includes rolling the steel sheet until the thickness of the steel sheet is further reduced by at least 80%, air cooling the steel sheet, and reheating the steel sheet. The method also includes secondary quenching of the steel sheet and tempering of the steel sheet. The method also includes cutting the steel sheet into a plurality of steel strips and shaping the steel strips into a plurality of steel spokes.

Description

Technical Field

[0001] The present disclosure relates to a non-pneumatic tire. More specifically, the present disclosure relates to a non-pneumatic tire having spokes formed by a thermomechanically controlled process. The resulting spokes can be formed from multiple layers. Background Art

[0002] Various tire constructions have been developed that enable the tire to be driven in an uninflated or underinflated state. Non-pneumatic tires do not require inflation, while "run-flat tires" can continue to be driven at relatively high speeds for extended periods of time after being punctured and partially or completely depressurized. Non-pneumatic tires may include support structure, such as spokes or webs, connecting a lower ring to an upper ring. In some non-pneumatic tires, a circumferential tread may be attached to the upper ring of the tire.

[0003] Non-pneumatic tires can use high-strength, high-toughness materials to achieve the required performance. Steel components can be used as load-bearing components in non-pneumatic tires due to the many options and preparation methods available to produce the required properties. Summary of the Invention

[0004] In one embodiment, a method of manufacturing a non-pneumatic tire includes: providing a lower ring; providing an upper ring; providing a plurality of steel plates; and heating the plurality of steel plates to a temperature between 1000°C and 1200°C. The method also includes: stacking the plurality of steel plates on top of each other to form a layered steel plate having a first thickness; and rolling the layered steel plates at a temperature between 900°C and 1100°C until the layered steel plate has a second thickness less than the first thickness. The method also includes: performing a first quench on the layered steel plates; and reheating the layered steel plates to a temperature between 400°C and 500°C. The method also includes: rolling the layered steel plates until the layered steel plates have a third thickness less than the second thickness; and air cooling the layered steel plates to room temperature. The method also includes: reheating the layered steel plates to a temperature between 790°C and 830°C; performing a second quench on the layered steel plates; and tempering the layered steel plates at a temperature between 200°C and 300°C. The method further includes: cutting the layered steel plate into a plurality of layered steel strips; and forming the layered steel strips into a plurality of layered steel spokes, wherein each of the plurality of layered steel spokes has a first end and a second end. The method further includes: connecting the first end of each of the plurality of layered steel spokes to the lower ring; and connecting the second end of each of the plurality of layered steel spokes to the upper ring. The method further includes: applying a tread layer to the upper surface of the upper ring.

[0005] In another embodiment, a non-pneumatic tire includes: a lower ring having a first diameter; and an upper ring coaxial with the lower ring and having a second diameter greater than the first diameter. The non-pneumatic tire also includes a plurality of spokes extending from the lower ring to the upper ring, wherein each of the plurality of spokes has a first end connected to the lower ring and a second end connected to the upper ring. Each of the plurality of spokes is formed from a plurality of steel layers, wherein each steel layer extends from the first end of the spoke to the second end of the spoke. The plurality of steel layers includes at least one first steel layer having a first carbon content, a first strength, and a first elongation. The plurality of steel layers also includes at least one second steel layer having a second carbon content, a second strength, and a second elongation, wherein the first carbon content is greater than the second carbon content, the first strength is greater than the second strength, and the first elongation is less than the second elongation.

[0006] In another embodiment, a method of manufacturing a spoke for a non-pneumatic tire includes providing a steel plate; heating the steel plate to a temperature of at least 1000°C; and rolling the steel plate at a temperature of at least 900°C until the thickness of the steel plate has been reduced by at least 80%. The method also includes performing a first quench on the steel plate and reheating the steel plate to a temperature of at least 400°C. The method also includes rolling the steel plate until the thickness of the steel plate has been further reduced by at least 80%, air cooling the steel plate, and reheating the steel plate to a temperature of at least 790°C. The method also includes performing a second quench on the steel plate and tempering the steel plate at a temperature of at least 200°C. The method also includes cutting the steel plate into a plurality of steel strips and forming the steel strips into a plurality of steel spokes. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the accompanying drawings, structures are shown which, together with the detailed description provided below, describe exemplary embodiments of the invention as claimed. Similar elements are designated by the same reference numerals. It should be understood that elements shown as a single component may be replaced with multiple components, and elements shown as multiple components may be replaced with a single component. The drawings are not drawn to scale, and the proportions of certain elements may be exaggerated for illustrative purposes.

[0008] Figure 1 is a side view of one embodiment of a non-pneumatic tire,

[0009] Figure 2 yes Figure 1 Detail of a portion of a , with some features removed for clarity,

[0010] Figure 3 This is a perspective view of the steel plate.

[0011] Figure 4is a time-temperature diagram of an exemplary method for processing a steel plate,

[0012] Figure 5A and Figure 5B is a simplified diagram showing an exemplary steel plate stack,

[0013] 6A to 6D is a simplified diagram showing an additional exemplary steel plate stack, and

[0014] Figure 7A and Figure 7B is a simplified diagram of a layered spoke. DETAILED DESCRIPTION

[0015] The following includes definitions of selected terms used herein. These definitions include various examples or forms of components that fall within the scope of the term and can be used for implementation. The examples are not intended to be limiting. Both singular and plural forms of the terms may be included within the definitions.

[0016] "Axial" and "axially" refer to directions parallel to the tire's axis of rotation.

[0017] “Circumferential” and “circumferentially” refer to directions perpendicular to the axial direction extending along the circumference of the surface of the tread.

[0018] "Radial" and "radially" refer to directions perpendicular to the tire's axis of rotation.

[0019] As used herein, "tread" means that portion of the tire that comes into contact with the road or ground under normally inflated and normally loaded conditions.

[0020] Although similar terms are used in the following description to describe common tire components, it should be understood that because these terms carry slightly different meanings, one of ordinary skill in the art would not consider any of the following terms to be completely interchangeable with another term used to describe common tire components.

[0021] Directions are described herein with reference to the tire's axis of rotation. The terms "upward" and "upwardly" refer to a general direction toward the tire's tread, while "downward" and "downwardly" refer to a general direction toward the tire's axis of rotation. Thus, when relative directional terms such as "upper" and "lower" or "top" and "bottom" are used in conjunction with an element, the "upper" or "top" element is spatially closer to the tread than the "lower" or "bottom" element. Furthermore, when relative directional terms such as "above" or "below" are used in conjunction with an element, if an element is "above" another element, it means that the element is closer to the tread than the other element.

[0022] The terms "inwardly" and "inwardly" refer to general directions toward the equatorial plane of the tire, while "outwardly" and "outwardly" refer to general directions away from the equatorial plane of the tire and toward the sides of the tire. Thus, when relative directional terms such as "inner" and "outer" are used in connection with an element, the "inner" element is spatially closer to the equatorial plane of the tire than the "outer" element.

[0023] Figure 1 and Figure 2 One embodiment of a non-pneumatic tire 10 is shown. The non-pneumatic tire 10 is shown for exemplary purposes only and is not intended to be limiting. In the illustrated embodiment, the non-pneumatic tire 10 includes a generally annular lower ring 20. The lower ring 20 can engage a vehicle wheel hub (not shown) to attach the tire 10 to the vehicle. The lower ring 20 can be made of a polymeric material, an elastomeric material, a metal, a composite material composed of a polymer reinforced with glass or carbon fiber, or any other desired material or combination of materials.

[0024] The non-pneumatic tire 10 also includes a generally annular upper ring 30. The upper ring 30 has a diameter greater than the diameter of the lower ring 20 and is substantially coaxial with the lower ring 20. The upper ring 30 can be made of a polymeric material, an elastomeric material, a metal, a composite material composed of a polymer reinforced with glass or carbon fiber, or any other desired material or combination of materials. The lower ring 20 and the upper ring 30 can be made of the same material or different materials.

[0025] A circumferential tread 40 is attached to the upper ring 30. The circumferential tread 40 may be attached to the upper ring 30 adhesively, mechanically, or by any other desired arrangement. The circumferential tread 40 may be made of rubber and may include tread elements (not shown) such as grooves, ribs, blocks, lugs, sipes, studs, or any other desired tread elements. The tread band may include a filament assembly.

[0026] In the illustrated embodiment, the circumferential tread 40 is shown as a single layer. In alternative embodiments, the tread may be a multi-layer belt. Such a multi-layer tread band may include one or more layers of substantially inextensible material. These layers may be formed from sheets of material, strands of material, filaments of material, or any other desired arrangement. In other alternative embodiments, the multi-layer tread band may include layers of extensible material, such as an elastomer. In one exemplary embodiment, the tread band may include a pair of inextensible layers separated by a layer of extensible material. In other alternative embodiments, the tread band may include a belt known as a shear belt, shear element, or a thin, annular, high-strength belt element.

[0027] Spokes 50 connect lower ring 20 to upper ring 30. Each spoke 50 has a first end connected to lower ring 20 and a second end connected to upper ring 30. In the illustrated embodiment, the spokes 50 are arranged in two axially spaced sets of spokes, including a first set of spokes extending in a first direction and a second set of spokes extending in a second direction opposite the first direction. In alternative embodiments, a single set of spokes may be employed, with each spoke extending in the same direction. In yet another alternative embodiment, three or more axially spaced sets of spokes may be employed.

[0028] In the illustrated embodiment, a first end of each spoke 50 is directly connected to the lower ring 20. The first ends of the spokes 50 can be connected to the lower ring 20 by welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), a key / keyway connection, or any other desired arrangement. The second end of each spoke 50 is connected to the flexure member 60, which is in turn connected to the upper ring 30. In other words, the second end of each spoke 50 is indirectly connected to the upper ring 30.

[0029] The flexure member 60 can be made of a polymer (e.g., polyurethane or rubber), a thin, bent piece of metal, or any other desired material or combination of materials. In the illustrated embodiment, the flexure member 60 is configured as a rectangular parallelepiped and is arranged so that the ends of the flexure member 60 are aligned with the second ends of the spokes 50. In other alternative embodiments, the flexure member can be arranged so that the ends of the flexure member are set back relative to the second ends of the spokes, or can be arranged so that the ends of the flexure member extend beyond the second ends of the spokes. In other alternative embodiments, the flexure member can be replaced with a mechanical pin joint (i.e., a hinge).

[0030] The flexure member 60 includes a spoke-facing surface and a ring-facing surface. The spoke-facing surface of the flexure member 60 is attached to the spokes 50, and the ring-facing surface is attached to the upper ring 30. Attachment between the flexure member 60 and the spokes 50 or between the flexure member 60 and the upper ring 30 can be achieved using welding, brazing, soldering, adhesives, mechanical fasteners (e.g., bolts, rivets), a key / keyway connection, or any other desired arrangement. For example, attachment can be provided by pouring polyurethane directly onto the spokes, with or without first coating the spokes with a primer.

[0031] Although the illustrated embodiment shows the first end of each spoke 50 being directly connected to the lower ring 20 and the second end being indirectly connected to the upper ring 30, it should be understood that other arrangements may be used. For example, in an alternative embodiment, the first end of each spoke is indirectly connected to the lower ring, and the second end of each spoke is directly connected to the upper ring. In another alternative embodiment, the first end of each spoke is indirectly connected to the lower ring, and the second end of each spoke is also indirectly connected to the upper ring. In another alternative embodiment, the first end of each spoke is directly connected to the lower ring, and the second end of each spoke is also directly connected to the upper ring.

[0032] Figure 2 is a detailed view of a portion of a non-pneumatic tire 10, with some features removed for clarity. As can be seen in this view, each spoke 50 has a thickness t in a generally circumferential direction. Thickness t can range from 1.5 mm to 5 mm. In one specific embodiment, each spoke 50 has a thickness t of 3 mm. In the illustrated embodiment, each spoke 50 has a constant thickness t. In alternative embodiments, the thickness of the spoke can vary between the first and second ends. For example, the spoke can have relatively thicker portions at the first and second ends, and a relatively thinner portion between the ends. Each spoke also has a width in a generally axial direction.

[0033] In one embodiment, each spoke 50 is constructed of steel. More specifically, the spoke 50 is constructed of ultra-high strength steel produced using a thermo-mechanically controlled process (TMCP) production method. In one embodiment, the spoke 50 is a layered spoke constructed of multiple steel layers.

[0034] The foundation behind TMCP steel production is that a controlled temperature profile within the steel plate ensures the formation of the desired steel microstructure. Warm rolling is also utilized to mechanically reduce the gauge of the steel, reduce the grain size of the constituents within the matrix, and accelerate the production of a microstructure capable of achieving ultra-high strength (i.e., strength greater than or equal to 2000 MPa) while maintaining acceptable elongation (i.e., at least 3% elongation). TMCP has previously been used in large applications involving thick plate, such as steel plates for ship hulls. However, TMCP is challenging at thinner gauges because it is more difficult to control the properties of the resulting product. Consequently, TMCP has long been considered unsuitable for smaller applications requiring thin steel plates, such as those less than 1 cm thick.

[0035] Figure 3is a perspective view of an exemplary steel plate 100 for forming a plurality of spokes. In one embodiment, a single steel plate is used to form the spokes. In an alternative embodiment, multiple steel plates can be stacked and processed to ultimately form layered spokes. The steel plate 100 can be formed from any number of steel types. For example, the steel plate 100 can be Damascus steel or blade steel, or similar steel types. Such steel types have a high carbon content of at least 0.60%, ultra-high strength (i.e., an ultimate tensile strength of at least 2000 MPa or 290 ksi), and medium elongation (i.e., an elongation of at least 3%). For another example, the steel plate 100 can be formed from steel having a low-medium carbon content of less than 0.60%, high strength (i.e., an ultimate tensile strength of 1200 MPa to 2000 MPa or 174 ksi to 290 ksi), and high elongation (i.e., an elongation of at least 10%). For another example, a plate of two steel types can be used.

[0036] The initial thickness t0 of the plate 100 can be significantly greater than the thickness t of each spoke 50. Where the spoke 50 is formed from a single steel plate 100, the plate can have an initial thickness t0 between 50 mm and 500 mm. Where the spoke 50 is formed from a plurality of stacked plates, the stack can have a combined initial thickness between 50 mm and 500 mm.

[0037] Figure 4 FIG2 is a time-temperature graph for an exemplary method of processing a steel plate using TMCP. The graph is not drawn to scale. Although certain temperature values ​​and other symbols are shown on the graph, it should be understood that these values ​​are merely exemplary.

[0038] The process begins by heating a steel plate 100 (or multiple steel plates) to an elevated temperature. In a time-temperature diagram, the plate is heated to a temperature of 1200°C and then held at that temperature for two hours. In one embodiment, it takes 30 minutes per inch of thickness to reach a temperature of 1200°C. In an alternative embodiment, the plate can be heated to a temperature between 900°C and 1300°C and held at that temperature for two hours. Heating the plate to such a temperature homogenizes the steel. The temperature can be selected based on the carbon content of the steel. Temperatures between 900°C and 1300°C are suitable for steels with a carbon content of 0.15% to 0.80%.

[0039] Where multiple plates are used, the multiple steel plates are stacked on top of each other during or immediately after the initial heating phase. The stacking of multiple plates produces a layered steel plate.

[0040] Figure 5A and Figure 5B is a simplified diagram illustrating an exemplary steel plate stack 200 . Figure 5AA steel plate stack 200A is shown having alternating layers of high carbon steel plates 210 and low carbon steel plates 220. Each high carbon steel plate 210 has a carbon content of at least 0.60%, while the low carbon steel plates 220 have a carbon content of less than 0.60%. Figure 5A In the embodiment, the high carbon steel plate 210 forms the outermost layer and sandwiches the low carbon steel plate 220 .

[0041] The high-carbon steel plates 210 can be referred to as a plurality of first steel plates having a first strength and a first elongation, and the low-carbon steel plates 220 can be referred to as second steel plates having a second strength and a second elongation. The first strength is greater than the second strength, and the second elongation is greater than the first elongation. For example, the first strength of the finished product can be at least 2000 MPa, while the second strength is between 1200 MPa and 2000 MPa. The first elongation of the finished product can be at least 3%, while the second elongation can be at least 10%.

[0042] Figure 5B A steel plate stack 200B is shown having alternating layers of high carbon steel plates 210 and low carbon steel plates 220. The high carbon steel plates 210 and low carbon steel plates 220 are similar to those described above with reference to Figure 5A The steel plates are essentially the same. Figure 5B In the embodiment, the low carbon steel plates 220 form the outermost layer and sandwich the high carbon steel plates 210 in between.

[0043] Figure 5A and Figure 5B Three layers are shown for illustrative purposes. In practice, it may be desirable to form spokes with more layers. 6A to 6D is a simplified diagram showing additional exemplary layers of a steel plate. Figure 6A A steel plate stack 200C is shown having three high carbon steel plates 210 and three low carbon steel plates 220. In this embodiment, one high carbon steel plate 210 forms a first outer layer, while one low carbon steel plate 220 forms a second outer layer opposite the first outer layer.

[0044] Figure 6B A steel plate stack 200D is shown having five high carbon steel plates 210 and five low carbon steel plates 220. In this embodiment, one high carbon steel plate 210 forms a first outer layer, while one low carbon steel plate 220 forms a second outer layer opposite the first outer layer.

[0045] Figure 6C A steel plate stack 200E is shown having ten high carbon steel plates 210 and ten low carbon steel plates 220. In this embodiment, one high carbon steel plate 210 forms a first outer layer, while one low carbon steel plate 220 forms a second outer layer opposite the first outer layer.

[0046] Figure 6DA steel plate stack 200F is shown having twenty high carbon steel plates 210 and twenty low carbon steel plates 220. In this embodiment, one high carbon steel plate 210 forms a first outer layer, while one low carbon steel plate 220 forms a second outer layer opposite the first outer layer.

[0047] Figures 5A to 5B and 6A to 6D The embodiments shown in are merely exemplary and non-limiting. In one known embodiment, each steel spoke is made from a stack of 10 to 20 steel plates. In another known embodiment, each steel spoke is made from a stack of 20 to 30 steel plates. In another known embodiment, each steel spoke is made from a stack of 30 to 40 steel plates. In another known embodiment, each steel spoke is made from a stack of 40 to 50 steel plates. In other words, each steel spoke may be made from a stack of 10 to 50 steel plates. In each case, the layers may alternate between a first steel plate and a second steel plate. In alternative embodiments, it may be desirable to use a continuous plate of the same material. In other alternative embodiments, it may be desirable to use three or more different types of steel plates. The outer layers of each stack may be formed from the same steel type or different steel types.

[0048] return Figure 4 After the initial heating step is completed, the steel plate 100 (or steel plate stack 200) is rolled at a normalized temperature between 900°C and 1100°C until the thickness of the plate 100 (or steel plate stack) has been reduced by 90%. This rolling step can be referred to as a hot rolling process. In other embodiments, the plate can be rolled until its thickness has been reduced by 80% to 99%. In other words, after this rolling process, the thickness of the steel plate 100 (or steel plate stack 200) can be between 1% and 20% of the initial thickness. In one embodiment, at this stage, the thickness of the steel plate or steel plate stack is between 10 mm and 100 mm.

[0049] After the rolling process, the steel plate 100 (or steel plate stack 200) is rapidly cooled by a first quench. As shown in the temperature-time diagram, the quench is an oil quench. The oil quench cools the steel at a rate between 5°C / min and 10°C / min and creates a martensitic structure within the steel plate 100. In other embodiments, alternative quenching media, such as ethylene glycol, water, or nitrogen, may be used.

[0050] The steel plates 100 (or stack of steel plates 200) are then subjected to a deformation tempering ("TF") step, in which the plates are reheated at a rate between 5°C / min and 10°C / min to a temperature of 500°C. The heating rate will affect the grain growth within each plate.

[0051] In other embodiments, the plate is reheated to a temperature between 400° C. and 600° C. Importantly, the plate is reheated to a temperature below the point at which ferrite transforms to austenite, which is depicted as A1 in the temperature time diagram.

[0052] When the steel is at an elevated temperature, the steel plate 100 (or steel plate stack 200) is rolled again. This process may be referred to as rewarming. Figure 4 As shown in the time-temperature diagram of , the steel plate 100 (or steel plate stack 200) is rolled until its thickness is reduced by another 85%. In other embodiments, the plate is rolled until its thickness has been reduced by 80% to 99%. In other words, the thickness of the steel plate 100 (or steel plate stack 200) can be between 1% and 20% of the previous thickness. This thickness is the final plate specification. In one embodiment, at this stage, the thickness of the steel plate or steel plate stack is between 2mm and 5mm. When using a steel plate stack, at this stage, each layer of steel can be between 0.04mm and 0.5mm (40μm to 500μm).

[0053] This rewarming process results in a microstructure of ultrafine elongated ferrite grains and fine carbides uniformly distributed throughout the matrix. Deforming at these lower temperatures requires significant forces because the steel is quite hard, but is necessary to introduce plastic deformation into the steel.

[0054] After the warm rolling process is complete, the steel plate 100 (or steel plate stack 200) is air-cooled until it reaches room temperature. After cooling, the steel plate 100 (or steel plate stack 200) is reheated again. This time it is reheated to a temperature A2 above the point at which ferrite transforms into austenite. For example, the plate can be heated to a temperature between 790°C and 830°C. The plate is then held at this temperature to allow carbides to dissolve, thereby allowing the grain size in the final martensite to grow. In one embodiment, this can occur in less than ten minutes. In other embodiments, it can be maintained for a significantly longer period of time.

[0055] The steel plate 100 (or steel plate stack 200) is then subjected to a second quench. In one embodiment, the second quench is a water quench, which reduces the temperature at a rate between 10°C / min and 20°C / min, depending on the water temperature. In alternative embodiments, the second quench can be performed using oil, ethylene glycol, or nitrogen. This second quench produces the final ultrafine martensitic structure. The steel plate 100 (or steel plate stack 200) is then tempered at a relatively low temperature (200°C to 300°C) to relieve internal stress and increase the material's overall elongation. The steel plate 100 (or steel plate stack 200) is then air-cooled again to room temperature.

[0056] After the TMCP process is completed, the steel sheets 100 (or the stack of steel sheets 200 ) may then be formed into spokes. Figure 7A and Figure 7B is a simplified diagram of a layered spoke 300. In both figures, each layer extends along the entire length of the spoke 300 from a first end of the spoke to a second end of the spoke.

[0057] Figure 7A A spoke 300A is shown in which a high carbon steel layer 310 surrounds a low carbon steel layer 320. This arrangement corresponds to Figure 5A The steel plate stack 200A is shown in FIG.

[0058] Figure 7B A spoke 300B is shown in which a low carbon steel layer 320 surrounds a high carbon steel layer 310. This arrangement corresponds to Figure 5A The steel plate stack 200A is shown in FIG.

[0059] It should be understood that Figure 7A and Figure 7B The spokes 300 in FIG. 3 are merely exemplary. The spokes may be formed from a single plate or any stack of the above plates.

[0060] To form the spokes, the operator cuts the steel sheet 100 (or the stack of steel sheets 200) into a plurality of steel strips. The steel strips may be solid steel strips or layered steel strips. The operator then shapes the steel strips into a plurality of steel spokes, each of the plurality of layered steel spokes having a first end and a second end. In one embodiment, the operator forms at least one curve in the steel strip to form the spokes. Figure 7A and Figure 7B In the embodiment shown, the operator forms a plurality of curves in the steel strip to form the spokes 300. The operator then connects the first end of each steel spoke to the lower ring and the second end of each of the plurality of layered steel spokes to the upper ring. This forms a non-pneumatic tire structure such as Figure 1 The operator may then apply the tread layer to the upper surface of the upper ring to complete the construction of the non-pneumatic tire.

[0061] In one embodiment, the spokes are formed after the TF process but before reheating and a second quench. In another embodiment, the spokes are formed after reheating and a second quench. Forming the spokes before reheating and a second quench can prevent the part from cracking during forming.

[0062] To the extent that the terms "including" or "having" are used in the specification or claims, they are intended to be inclusive in a manner similar to the way the term "comprising" is understood when used as a transition word in the claims. Furthermore, to the extent that the term "or" is used (e.g., A or B), the term is intended to mean "A or B or both." When the applicant intends to indicate "only A or B but not both," the term "only A or B but not both" will be used. Thus, the use of the term "or" herein is inclusive and not exclusive. See Bryan A. Garner, A Dictionary of Modern Legal Usage 624 (2d. Ed. 1995). Furthermore, to the extent that the terms "in" or "into" are used in the specification and claims, the terms are intended to mean "on" or "onto." Furthermore, to the extent the term “connected” is used in the specification or claims, the term is intended to mean not only “directly connected to,” but also “indirectly connected to,” such as connected through another component or components.

[0063] While the present application has been illustrated by way of description of its embodiments, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such details. Additional advantages and modifications will be readily apparent to those skilled in the art. Therefore, the present application, in its broader aspects, is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. For example, each spoke may be provided with a rubber coating to cushion the impact when contact occurs between adjacent spokes. Accordingly, departures from such details may be made without departing from the spirit or scope of the applicant's overall inventive concept.

Claims

1. A method for manufacturing a non-pneumatic tire, the method comprising: Provide lower ring; Provide upper ring; Provide multiple steel plates; heating the plurality of steel plates to a temperature between 1000° C. and 1200° C.; stacking the plurality of steel plates on top of each other to form a layered steel plate having a first thickness; rolling the layered steel sheet at a temperature between 900° C. and 1100° C. until the layered steel sheet has a second thickness less than the first thickness; performing a first quenching on the layered steel plate; reheating the layered steel sheet to a temperature between 400° C. and 500° C.; rolling the layered steel plate until the layered steel plate has a third thickness that is less than the second thickness; air-cooling the layered steel plates to room temperature; reheating the layered steel sheet to a temperature between 790° C. and 830° C.; performing a second quenching on the layered steel plate; Tempering the layered steel sheet at a temperature between 200° C. and 300° C.; cutting the layered steel plate into a plurality of layered steel strips; forming the layered steel strip into a plurality of layered steel spokes, each steel spoke in the plurality of layered steel spokes having a first end and a second end; connecting the first end of each of the plurality of layered steel spokes to the lower ring; connecting the second end of each of the plurality of layered steel spokes to the upper ring; as well as A tread layer is applied to the upper surface of the upper ring.

2. The method according to claim 1, wherein The plurality of steel plates include a plurality of first steel plates having a first strength and a first elongation and a plurality of second steel plates having a second strength and a second elongation, wherein the first intensity is greater than the second intensity, and Wherein, the second elongation is greater than the first elongation.

3. The method according to claim 2, wherein: The first strength is at least 2000 MPa, and the second strength is between 1200 MPa and 2000 MPa. The method of claim 2 , wherein the first elongation is at least 3% and the second elongation is at least 10%. The method of claim 1 , wherein the second thickness is 1% to 20% of the first thickness, and wherein the third thickness is 1% to 20% of the second thickness. The method of claim 1 , wherein the third thickness is between 2 mm and 5 mm. The method of claim 1 , wherein the first quenching is performed using oil. The method according to claim 1 , wherein the second quenching is performed using water.

9. A non-pneumatic tire, comprising: a lower ring having a first diameter; an upper ring having a second diameter greater than the first diameter, the upper ring being coaxial with the lower ring; a plurality of spokes extending from the lower ring to the upper ring, wherein each of the plurality of spokes has a first end connected to the lower ring and a second end connected to the upper ring, wherein each of the plurality of spokes is formed from a plurality of steel layers, wherein each of the plurality of steel layers extends from the first end of the spoke to the second end of the spoke, wherein the plurality of steel layers include at least one first steel layer, the first steel layer having a first carbon content, a first strength, and a first elongation, wherein the plurality of steel layers include at least one second steel layer, the second steel layer having a second carbon content, a second strength, and a second elongation, wherein the first carbon content is greater than the second carbon content, wherein the first intensity is greater than the second intensity, and Wherein, the first elongation is smaller than the second elongation.

10. The non-pneumatic tire according to claim 9, wherein: The first end of each of the plurality of spokes is directly connected to the lower ring, and wherein the second end of each of the plurality of spokes is indirectly connected to the upper ring.

11. The non-pneumatic tire according to claim 9, wherein: The plurality of steel layers includes at least ten steel layers.

12. The non-pneumatic tire according to claim 9, wherein: The plurality of steel layers includes 30 to 50 steel layers.

13. The non-pneumatic tire according to claim 9, wherein: Each spoke of the plurality of spokes has a thickness of less than 5 mm.

14. The non-pneumatic tire according to claim 9, wherein: The first carbon content is at least 0.60%, and wherein the second carbon content is less than 0.60%.

15. The non-pneumatic tire according to claim 9, wherein: The plurality of steel layers includes alternating first steel layers and second steel layers.

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