Vehicle wheel disk

Abstract

The present invention provides a vehicle wheel disk comprising: a fixing unit; and a spoke unit extending radially outward from the fixing unit. The fixing unit comprises: a fixing body having a fixing hole formed through the center portion thereof; and multiple fastening portions formed in the fixing body and spaced apart from each other around the fixing hole to be fastened to an object to be fixed. When a virtual circle connecting the center portions of fastening holes of the fastening portions is referred to as a hole connection circle and when a portion surrounded by the hole connection circle, the spoke unit, and the fastening portions is referred to as a reference area, the fixing unit comprises a reference surface that is brought into contact with the object to be fixed in at least a partial area of the reference area when installed on the object to be fixed.

Description

wheel discs for vehicles

[0001] The present invention relates to a wheel disc for a vehicle.

[0002] It is to be noted that the content described in this section merely provides background information for the present invention and does not constitute prior art.

[0003] As illustrated in Fig. 1, a durability performance evaluation (Cornering Fatigue Test) can be performed on a conventional steel wheel for a vehicle. Of course, the same durability performance evaluation can be performed by mounting a vehicle wheel disk (10) of the present invention, which will be described later, instead of the vehicle wheel disk (10) of a conventional steel wheel for a vehicle.

[0004] The durability performance evaluation method illustrated in Fig. 1 is briefly described as follows.

[0005] As shown in Fig. 1, a conventional vehicle wheel disk (10) is bolted and connected to a drum (20) connected to an axle (40), and a wheel rim (30) connected to the vehicle wheel disk (10) is fixed to a rotating table (50).

[0006] Afterwards, a load is applied in a direction perpendicular to the direction of the axle (40) from the lower part of the axle (40), and the durability performance can be evaluated by rotating the rotating table (50) to apply a moment load.

[0007] Referring to FIG. 2, a conventional steel wheel has a vehicle wheel disk (10) mounted on a drum (20), and a reference surface (11) can be mounted (in contact) on the drum (20).

[0008] Referring to FIGS. 1 and 2, since the conventional steel wheel has a large circular surface (11) and is mounted on the drum (20), the shaking of the vehicle wheel disk (10) is reduced when evaluating durability, thereby reducing the stress applied to the bolt and improving the durability life of the bolt.

[0009] Most conventional steel wheels have a circular base surface (11), and a large surface area is generally in contact with the drum (20). Therefore, when evaluating the durability of a conventional steel wheel vehicle wheel disc (10), the bolts rarely break or become loose during the durability evaluation.

[0010] However, as in recent times, when the material of the vehicle wheel disc (10) is made of high strength and is not well seated on the drum (20), there is a problem in that the bolts fixing the vehicle wheel disc (10) are preferentially broken before the vehicle wheel disc (10) is broken during the durability performance evaluation.

[0011] (Patent Document 1) KR 10-1518626 B1

[0012] In one aspect, the present invention aims to provide a wheel disk for a vehicle that can prevent bolts from loosening or breaking when evaluating the durability of the wheel disk.

[0013] The objectives of the present invention are not limited to the above-described scope. Those skilled in the art will have no difficulty understanding the additional objectives of the present invention from the overall content of this specification.

[0014] In one aspect for achieving the above object, the present invention provides a wheel disk for a vehicle, comprising: a fixed unit; and a spoke unit formed to extend radially outward from the fixed unit; wherein the fixed unit comprises: a fixed body having a fixed hole formed through a central portion thereof; and a plurality of fastening portions formed in the fixed body and spaced apart from the periphery of the fixed hole so as to be fastened to a fixed object; wherein an imaginary circle connecting the central portions of the fastening holes of the fastening portions is referred to as a hole connecting circle, and a portion surrounded by the hole connecting circle, the spoke unit, and the fastening portion is referred to as a reference area; and wherein the fixed unit, when installed on the fixed object, includes a reference surface that comes into contact with the fixed object in at least a portion of the reference area.

[0015] The vehicle wheel disc of the present invention has the effect of preventing bolts from loosening or breaking when evaluating the durability of the vehicle wheel disc.

[0016] The above reference surface can be in contact with the fixed object in the entire area of ​​the above reference area.

[0017] The above-mentioned fixed unit may include: a reference surface formed in a portion of the reference area and in contact with the fixed object; and a first step surface formed in a portion of the reference area excluding the reference surface and not in contact with the fixed object.

[0018] The above fixed unit may include a second step surface, at least a portion of which is not in contact with the fixed object, on the radially inner side of the hole connecting member.

[0019] The above-mentioned fixed unit may have a hole edge formed on the edge portion that contacts the above-mentioned fixed hole, and the above-mentioned fastening portion may be installed to connect between the above-mentioned spoke unit and the above-mentioned hole edge.

[0020] The area of ​​the reference plane on the plane may be 20% or more of the area of ​​the reference area.

[0021] The first step surface and the second step surface may have a distance of less than 1 mm from the fixed object in the axial direction.

[0022] The above reference surface may be formed at a portion of the above reference area that is in contact with the connecting point where the spoke unit and the fastening portion are connected.

[0023] Two of the above reference areas can be arranged with one of the above fastening portions in between.

[0024] The reference area can be arranged in a symmetrical manner based on the hole extension line, which is a virtual extension line connecting the center part of the above-mentioned fixed hole and the center part of the above-mentioned fastening hole.

[0025] The above spoke unit may be formed so that at least a portion thereof extends to an inner area of ​​the hole connecting member, or may be arranged to be in contact with the hole connecting member.

[0026] The above spoke unit may include a spoke bead that protrudes while covering a portion where the spoke unit and the fastening portion come into contact, or a spoke bead that protrudes while covering a portion where the spoke unit and the fastening portion come into contact.

[0027] The above fixed unit may further include a fixed bead that connects the fastening portion and the spoke unit, or connects the fastening portion and the hole edge, in the inner area of ​​the hole connecting member.

[0028] The above fixed unit and the above spoke unit may be made of steel.

[0029] According to one embodiment of the present invention, there is an effect of preventing bolts from loosening or breaking when evaluating the durability of a vehicle wheel disk.

[0030] Figure 1 is a front view showing a state in which durability performance is evaluated for a conventional steel wheel for a vehicle.

[0031] Figure 2 is a plan view illustrating a conventional steel wheel for a vehicle.

[0032] FIG. 3 is a plan view illustrating a vehicle wheel including a vehicle wheel disc according to one embodiment of the present invention.

[0033] FIG. 4 is a plan view clearly illustrating the boundaries between the fixed unit and the spoke unit in the vehicle wheel disc included in FIG. 3.

[0034] Figure 5 is an enlarged detailed view of the square portion of Figure 4.

[0035] FIG. 6a is a plan view showing a partial detail of a vehicle wheel disc according to one embodiment of the present invention.

[0036] FIG. 6b is a plan view showing a partial detail of a vehicle wheel disc according to another embodiment of the present invention.

[0037] Fig. 7a is a plan view showing a vehicle wheel disk having a large area of ​​the reference surface in the vehicle wheel disk of Fig. 4.

[0038] Fig. 7b is a plan view showing a vehicle wheel disk having a smaller area of ​​the reference surface than the vehicle wheel disk of Fig. 4.

[0039] Fig. 8a is a drawing showing details around the reference plane of Fig. 7a.

[0040] Figure 8b is a drawing showing details around the reference plane of Figure 7b.

[0041] Fig. 9a is a cross-sectional view showing an example of the AA' direction of Fig. 8a.

[0042] Fig. 9b is a cross-sectional view showing another example in the AA' direction of Fig. 8a.

[0043] Figure 9c is a cross-sectional view taken along the BB' direction of Figure 8b.

[0044] Fig. 9d is a cross-sectional view showing another example in the BB' direction of Fig. 8b.

[0045] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. However, the embodiments of the present invention may be modified in various ways, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. The shapes and sizes of elements in the drawings may be exaggerated for clarity.

[0046] In describing the embodiments of the present invention, if a detailed description of a known technology related to the present invention is judged to unnecessarily obscure the gist of the present invention, such detailed description will be omitted. In addition, the terms described below are terms defined in consideration of their functions in the present invention, and these may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout this specification. The terminology used in the detailed description is only for the purpose of describing the embodiments of the present invention and should in no way be limiting. Unless clearly defined otherwise, expressions in the singular form include plural meanings.

[0047] In this description, expressions such as "including" or "having" are intended to indicate certain features, numbers, steps, operations, elements, portions or combinations thereof, and should not be construed to exclude the presence or possibility of one or more other features, numbers, steps, operations, elements, portions or combinations thereof other than those described.

[0048] In this specification, terms such as 'top', 'upper part', 'top surface', 'bottom', 'lower part', 'bottom', 'side', etc. are based on the drawings, and in reality, they may vary depending on the direction in which the elements or components are arranged.

[0049] Additionally, throughout the specification, when we say that a part is 'connected' to another part, this includes not only cases where it is 'directly connected', but also cases where it is 'indirectly connected' with other elements in between.

[0050] Below, the present invention will be described in detail through each embodiment or example of the present invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may be combined with other embodiments or examples. Therefore, the citation of a claim in the patent claims is only an example of an embodiment, and the technical concept of the present invention should not be interpreted solely as a combination with the cited claim, and combinations with various claims also fall within the scope of the technical concept of the present invention.

[0051] Hereinafter, the present invention will be described in detail through examples. However, it should be noted that the examples described below are intended only to illustrate and concretize the present invention and are not intended to limit the scope of the invention. This is because the scope of the invention is determined by the matters set forth in the patent claims and matters reasonably inferred therefrom.

[0052] A vehicle wheel may include a wheel rim (30) and a vehicle wheel disc (10).

[0053] Wheels for vehicles are one of the chassis components that must be durable enough to absorb vibrations and shocks from the road surface and support the weight of the vehicle.

[0054] The wheel rim (30) serves to maintain the tire attached to the vehicle wheel. The vehicle wheel disk (10) can be connected to a fixed object (20) such as a drum to prevent deformation of the wheel rim (30) and to connect it to the axle.

[0055] A vehicle wheel disc (10) can be respectively coupled to a fixed object (20) and a wheel rim (30), and the vehicle wheel disc (10) can connect between the fixed object (20) and the wheel rim (30).

[0056] Hereinafter, components included in a vehicle wheel disc (10) according to one embodiment of the present invention will be specifically described with reference to FIGS. 3 to 5.

[0057] FIG. 3 is a plan view illustrating a vehicle wheel including a vehicle wheel disc according to one embodiment of the present invention.

[0058] FIG. 4 is a plan view clearly illustrating the boundary between the fixed unit (100) and the spoke unit (200) in the vehicle wheel disk (10) included in FIG. 3, and FIG. 5 is an enlarged detailed view of the square portion of FIG. 4.

[0059] A vehicle wheel disc (10) according to one embodiment of the present invention may include a fixed unit (100) and a spoke unit (200). The fixed unit (100) may include a fixed body (110) and a fastening portion (130).

[0060] The fixed unit (100) can be fixed to a fixed object (20). For example, the fixed object (20) can be a drum coupled to an axle.

[0061] The fixed object (20) may be a portion to which the fixed unit (100) is fixed. For example, the fixed object (20) may be configured as a drum that is connected to an axle and rotates together with the axle. The fixed unit (100) is fixed to the fixed object (20), and the axle, the fixed object (20), and the fixed unit (100) can rotate together. Therefore, when the axle rotates, the fixed object (20), the vehicle wheel disk (10), and the wheel rim (30) can rotate together.

[0062] The fixed unit (100) may include a fixed body (110) and a fastening part (130).

[0063] The fixed body (110) may have a fixing hole (111) formed through the central portion.

[0064] A fastening portion (130) is formed on the fixed body (110), and a plurality of fastening portions are arranged spaced apart from each other around the fastening hole (111) so that they can be fastened to the fixed object (20). When a fastening member such as a bolt is fastened to each fastening portion (130), the fastening unit (100) can be fastened to the fixed object (20).

[0065] For example, four fastening parts (130) can be spaced apart and arranged around the fixing hole (111), and can be arranged radially at a 90-degree angle with respect to the fixing hole (111).

[0066] The spoke unit (200) may be formed to extend radially outward from the fixed unit (100). One side of the spoke unit (200) may be connected to the fixed unit (100), and the other side of the spoke unit (200) may be connected to the wheel rim (30). The spoke unit (200) may connect the fixed unit (100) and the wheel rim (30), and a vent hole (210) may be formed through the spoke unit (200).

[0067] When the area surrounded by the hole connection circle (S), the spoke unit (200) and the fastening portion (130), which is a virtual circle connecting the central portions of the fastening holes (131) of the fastening portion (130), is referred to as a reference area (P), the fastening unit (100), when installed on the fixed object (20), may include a reference surface (P1) that comes into contact with the fixed object (20) in at least a portion of the reference area (P).

[0068] The reference plane (P1) is a portion that comes into contact with the fixed object (20). When the vehicle wheel disc (10) of the present invention is installed on the fixed object (20), the reference plane (P1) can come into contact with the fixed object (20). Specifically, the reference plane (P1) is a portion where the fixed unit (100) of the vehicle wheel disc (10) comes into contact with the fixed object (20) before the fixed unit (100) is bolted to the fixed object (20).

[0069] When the fixed unit (100) and the fixed object (20) are fastened with bolts at multiple fastening portions (130), as the fixed unit (100) is deformed, a part of the first step surface (P2) described later may come into contact with the fixed object (20). However, even if the first step surface (P2) comes into contact with the fixed object (20) as the bolt is fastened, the first step surface (P2) that was not in contact with the fixed object (20) before the bolt fastening is not the reference surface (P1).

[0070] Referring to FIG. 5, the fixed unit (100) has a hole edge (150) formed on the edge portion that contacts the fixed hole (111), and the fastening portion (130) can be installed to connect between the spoke unit (200) and the hole edge (150).

[0071] For example, the fastening portion (130) may include a fastening bead (133) that protrudes while covering the portion where the fastening portion (130) and the hole edge (150) come into contact. As another example, the fastening portion (130) may include a fastening bead (133) that protrudes while covering the portion where the fastening portion (130) and the hole edge are close to each other.

[0072] A second step surface (Q) can be formed in the area between the hole connecting member (S) and the hole edge (150). That is, the hole edge (150) does not correspond to the second step surface (Q), and the hole edge (150) can have a separation distance (R) exceeding 1 mm from the fixed object (20) in the axial direction (D).

[0073] The hole frame (150) can be installed in a ring shape surrounding the fixing hole (111). The distance (R) between the hole frame (150) and the fixed object (20) can increase from the side farther from the fixing hole (111) to the side closer to the fixing hole (111).

[0074] The spoke unit (200) may be formed to extend to at least a portion of the inner area of ​​the hole connecting member (S) or may be arranged to be in contact with the hole connecting member (S). Accordingly, the reference area (P) may be defined as a certain area surrounded by the hole connecting member (S), the spoke unit (200), and the fastening portion (130).

[0075]

[0076] *For example, if the spoke unit (200) is formed such that at least a portion thereof extends to the inner area of ​​the hole connecting member (S), a portion where the inner areas of the spoke unit (200) and the hole connecting member (S) overlap occurs, and the reference area (P) can be specified as a certain area surrounded by the hole connecting member (S), the spoke unit (200), and the fastening portion (130).

[0077] As another example, when the spoke unit (200) is arranged so that at least some area is in contact with the hole connecting member (S), the reference area (P) can be specified as a certain area surrounded by the hole connecting member (S), the spoke unit (200), and the fastening portion (130).

[0078] Referring to FIG. 5, the spoke unit (200) may include a spoke bead (230) that protrudes while covering a portion where the spoke unit (200) and the fastening portion (130) come into contact, or that protrudes while covering a portion where the spoke unit (200) and the fastening portion (130) come into contact.

[0079] The spoke bead (230) is a component of the spoke unit (200), and when the spoke unit (200) includes the spoke bead (230), the reference area (P) can be specified as a portion surrounded by the spoke unit (200) including the spoke bead (230), the hole connecting member (S), and the fastening portion (130).

[0080] The fixed unit (100) and spoke unit (200) may be made of steel. That is, the vehicle wheel disc (10) may be made of steel.

[0081] The fixed unit (100) and the spoke unit (200) can be distinguished based on the bold line illustrated in Fig. 5. The fixed unit (100) can be placed on the inner side based on the bold line illustrated in Fig. 5. The spoke unit (200) can be placed on the outer side based on the bold line illustrated in Fig. 5.

[0082] FIG. 6a is a plan view showing a partial detail of a vehicle wheel disc (10) according to one embodiment of the present invention, and FIG. 6b is a plan view showing a partial detail of a vehicle wheel disc (10) according to another embodiment of the present invention.

[0083] The fixed unit (100) may further include a fixed bead (170). The fixed bead (170) may connect the fastening portion (130) and the spoke unit (200) in the internal area of ​​the hole connecting member (S) of the fixed unit (100), or connect the fastening portion (130) and the hole edge (150). The fixed bead (170) may protrude from the upper surface of the fixed body (110).

[0084] Referring to FIGS. 5 and 6a, the fixed bead (170) is installed along the hole connecting circle (S) and can connect the fastening portion (130) and the spoke unit (200).

[0085] Referring to FIG. 6b, two fixed beads (170) can be installed, one fixed bead (170) is installed along the hole connecting circle (S) and connects the fastening portion (130) and the spoke unit (200), and the remaining one fixed bead (170) has a 'V shape' or 'U shape' and can connect the fastening portion (130) and the hole edge (150).

[0086] FIG. 7a is a plan view illustrating a vehicle wheel disc (10) having a large area (V2) of a reference surface in the vehicle wheel disc (10) of FIG. 4, and FIG. 7b is a plan view illustrating a vehicle wheel disc (10) having a small area (V2) of a reference surface in the vehicle wheel disc (10) of FIG. 4.

[0087] Fig. 8a is a drawing showing details around the reference plane (P1) of Fig. 7a, and Fig. 8b is a drawing showing details around the reference plane (P1) of Fig. 7b.

[0088] Fig. 9a is a cross-sectional view illustrating an example of the AA' direction of Fig. 8a. Fig. 9b is a cross-sectional view illustrating another example of the AA' direction of Fig. 8a. Fig. 9c is a cross-sectional view illustrating an example of the BB' direction of Fig. 8b. Fig. 9d is a cross-sectional view illustrating another example of the BB' direction of Fig. 8b.

[0089] For reference, FIGS. 7a, 8a, 9a, and 9b are drawings illustrating a vehicle wheel disc (10) having a large area (V2) of the reference surface. FIGS. 7b, 8b, 9c, and 9d are drawings illustrating a vehicle wheel disc (10) having a small area (V2) of the reference surface.

[0090] Referring to FIGS. 7a and 8a, when the fixed unit (100) forms a reference surface (P1) in the entire reference area (P), there may be no first step surface (P2) in the reference area (P).

[0091] The reference surface (P1) can be in contact with the fixed object (20) in the entire area of ​​the reference area (P).

[0092] Referring to FIG. 7b and FIG. 8b, when the fixed unit (100) forms a reference plane (P1) in a part of the reference area (P), a first step plane (P2) can be formed in the remaining part of the reference area (P) excluding the reference plane (P1).

[0093] The fixed unit (100) may include a reference surface (P1) and a first step surface (P2).

[0094] The reference surface (P1) is formed in a part of the reference area (P) and can come into contact with the fixed object (20).

[0095] The first step surface (P2) is formed in the remaining portion of the reference area (P) excluding the reference surface (P1) and may not be in contact with the fixed object (20). The first step surface (P2) may not be in contact with the fixed object (20) in the remaining portion excluding the reference surface (P1).

[0096] The vehicle wheel disc (10) of the present invention includes a reference surface (P1) and a first step surface (P2) in a reference area (P), so that when a fixed object (20) and a fixed unit (100) are fastened with a bolt, the first step surface (P2) can be deformed in a direction closer to the fixed object (20) according to the fastening of the bolt, and the bolt can be prevented from being loosened by a force that causes the first step surface (P2) to return in a direction away from the fixed object (20).

[0097] The first step surface (P2) is connected to the reference surface (P1), and the first step surface (P2) can form a step with the reference surface (P1). The first step surface (P2) can be spaced apart from the fixed object (20) and not in contact with it.

[0098] Referring to FIGS. 8a and 8b, the fixed unit (100) may include a second step surface (Q).

[0099] The second step surface (Q) can be out of contact with the fixed object (20) at least in a portion of the radially inner side of the hole connection circle (S).

[0100] Referring to FIGS. 9A and 9B, the second step surface (Q) is connected to the reference surface (P1), and the second step surface (Q) can be spaced apart from the fixed object (20) and not in contact with it. The second step surface (Q) can be positioned at a position that protrudes from the reference surface (P1) in the axial direction (D). Specifically, the second step surface (Q) can be positioned to protrude in a direction away from the fixed object (20) than the reference surface (P1).

[0101] For example, the fixed object (20) may have a flat shape at a portion in contact with the reference plane (P1). For example, the fixed object (20) may have a flat shape at a portion facing the second step surface (Q).

[0102] Referring to FIGS. 9c and 9d, the second step surface (Q) may be connected to the first step surface (P2), and the first step surface (P2) may be connected to the reference surface (P1). The first and second step surfaces (P2, Q) may be spaced apart from and not in contact with the fixed object (20), respectively. The first and second step surfaces (P2, Q) may be arranged at positions that protrude more than the reference surface (P1) in the axial direction (D). Specifically, the first and second step surfaces (P2, Q) may be arranged to protrude in a direction away from the fixed object (20) more than the reference surface (P1).

[0103] For example, the fixed object (20) may have a flat shape at a portion in contact with the reference plane (P1). For example, the fixed object (20) may have a flat shape at a portion facing the first and second step planes (P2, Q).

[0104] On a plane, the area of ​​the reference surface (V2) may be 20% or more of the area of ​​the reference area (P) (V1).

[0105] In this way, the area (V2) of the reference surface on the plane must be formed to be at least 20% of the area (V1) of the reference area (P) so that the bolts do not break or loosen when evaluating the durability of the vehicle wheel disk (10).

[0106] Referring to Fig. 8a, the area (V2) of the reference plane and the area (V1) of the reference area (P) on the plane may be the same. In this case, the area (V2) of the reference plane on the plane may be 100% of the area (V1) of the reference area (P). In Figs. 9a and 9b, the areas (V2) of the reference plane on the plane may be the same.

[0107] Referring to Fig. 8b, the area (V2) of the reference plane on the plane may be a portion of the area (V1) of the reference area (P). For example, the area (V2) of the reference plane may be 20% or more of the area (V1) of the reference area (P). In Figs. 9c and 9d, the areas (V2) of the reference plane on the plane may be the same.

[0108] Referring to FIGS. 9a to 9d, the first step surface (P2) and the second step surface (Q) may have a separation distance (R) of less than 1 mm from the fixed object (20) in the axial direction (D).

[0109] For example, referring to FIGS. 9a and 9b, a step is formed between the reference plane (P1) and the second step plane (Q), and the second step plane (Q) protrudes more than the reference plane (P1) in the axial direction (D), so that the two can have a height difference in the axial direction (D). At this time, the height difference in the axial direction (D) between the reference plane (P1) and the second step plane (Q) can be within 1 mm.

[0110] As another example, referring to FIGS. 9c and 9d, a step is formed between the reference plane (P1) and the first step plane (P2), and the first step plane (P2) protrudes more than the reference plane (P1) in the axial direction (D), so that the two can have a height difference in the axial direction (D). At this time, the height difference in the axial direction (D) between the reference plane (P1) and the first step plane (P2) can be within 1 mm.

[0111] The reference surface (P1) is in contact with the fixed object (20), and the first and second step surfaces (P2, Q) are not in contact with the fixed object (20), while the first and second step surfaces (P2, Q) can be spaced apart from the fixed object (20) in the axial direction (D).

[0112] The first step surface (P2) and the second step surface (Q) must be formed to have a distance (R) of less than 1 mm from the fixed object (20) in the axial direction (D) so that the bolts do not break or loosen when evaluating the durability of the disk.

[0113] The reference surface (P1) can be formed at a portion of the reference area (P) that is in contact with the connecting point where the spoke unit (200) and the fastening portion (130) are connected.

[0114] Two reference areas (P) can be arranged with one fastening portion (130) between them.

[0115] For example, if the entire vehicle wheel disc (10) has four fastening portions (130), eight reference areas (P) can be arranged. A reference plane (P1) is formed in at least a portion of each reference area (P), and eight reference planes (P1) can be arranged in the entire vehicle wheel disc (10).

[0116] The reference area (P) can be arranged in a symmetrical manner based on the hole extension line (T), which is a virtual extension line connecting the center part of the fixed hole (111) and the center part of the fastening hole (131).

[0117] The hole extension line (T) is an extension of a straight line, and two reference areas (P) can be arranged symmetrically based on the hole extension line (T).

[0118] Referring to Fig. 9a, the second step surface (Q) may include a vertical surface (J) that forms a step with the reference surface (P1). When the vertical surface (J) is arranged on the second step surface (Q), the second step surface (Q) may form a step with the reference surface (P1).

[0119] Referring to Fig. 9b, the second step surface (Q) may include an inclined surface (K) that forms a step with the reference surface (P1). When the inclined surface (K) is arranged on the second step surface (Q), the second step surface (Q) may form a step with the reference surface (P1).

[0120] Referring to FIGS. 9a and 9b, when the fixed unit (100) forms a reference plane (P1) in the entire reference area (P) and there is no first step plane (P2) in the reference area (P), the second step plane (Q) can be connected to the first reference plane (P1). The second step plane (Q) can be non-contacted while forming a step with the reference plane (P1) and being spaced apart from the fixed object (20).

[0121] Referring to Fig. 9c, the first step surface (P2) may include a vertical surface (J) that forms a step with the reference surface (P1). When the vertical surface (J) is arranged on the first step surface (P2), the first step surface (P2) may form a step with the reference surface (P1).

[0122] Referring to FIG. 9d, the first step surface (P2) may include an inclined surface (K) that forms a step with the reference surface (P1). When the inclined surface (K) is arranged on the first step surface (P2), the first step surface (P2) may form a step with the reference surface (P1).

[0123] Referring to FIGS. 9c and 9d, the fixed unit (100) may form a reference plane (P1) in a portion of the reference area (P), and there may be a first step plane (P2) and a second step plane (Q) in the reference area (P). In this case, the first step plane (P2) may be connected to the first reference plane (P1). The first step plane (P2) may form a step with the reference plane (P1), and the first step plane (P2) may be spaced apart from the fixed object (20) and may not be in contact with it.

[0124] Hereinafter, with reference to Tables 1 and 2 and the drawings, the maximum bolt stress applied during the durability performance evaluation will be compared for a wheel disk of a conventional vehicle steel wheel (10, hereinafter referred to as a 'conventional wheel disk', see FIG. 2), Example 1 of a vehicle wheel disk (10) of the present invention (hereinafter referred to as a 'vehicle wheel disk of Example 1', see FIG. 6a), and Example 2 of a vehicle wheel disk (10) of the present invention (hereinafter referred to as a 'vehicle wheel disk of Example 2', see FIG. 6b).

[0125] The vehicle wheel disc (10) of the conventional vehicle steel wheel utilized the vehicle wheel disc (10) illustrated in FIG. 2.

[0126] In Example 1, a vehicle wheel disc (10) was used in which a reference surface (P1) was formed in the entire reference area (P) shown in Fig. 6a, and one fixed bead (170) was installed in a fixed unit (100).

[0127]

[0128] *In Example 2, a vehicle wheel disk (10) was used in which a reference surface (P1) was formed in the entire reference area (P) shown in Fig. 6a, and two fixed beads (170) were installed in a fixed unit (100).

[0129] Referring to FIG. 2, in the case of a conventional wheel disc, the reference surface (11) where the vehicle wheel disc (10) comes into contact with the fixed object (20) is secured considerably wide as a portion indicated by a circle, so that the vehicle wheel disc (10) is stably seated on the fixed object (20), and thus, shaking is reduced during durability performance evaluation, and the stress applied to the bolt can be reduced.

[0130] Referring to FIGS. 6a and 6b, the vehicle wheel disc (10) of Examples 1 and 2 cannot sufficiently secure a reference surface (P1, see FIG. 8a) where the vehicle wheel disc (10) comes into contact with the fixed object (20), unlike the conventional vehicle wheel disc (10) due to its designed shape.

[0131] Accordingly, the present invention provides a vehicle wheel disc (10) that can prevent bolts from loosening or breaking when evaluating durability of the vehicle wheel disc (10) even when the reference surface (P1) where the vehicle wheel disc (10) comes into contact with the fixed object (20) is smaller than that of a conventional vehicle wheel disc (10) in a designed shape, as in Examples 1 and 2.

[0132] Table 1 below is the analysis result derived through structural analysis of the stress applied to a conventional vehicle wheel disc (10) and the wheel disc bolts of Examples 1 and 2.

[0133]

[0134] STEP 1 of Table 1 shows the maximum bolt stress applied to the vehicle wheel disc (10) of Examples 1 and 2 and the conventional vehicle wheel disc (10) in a state where the vehicle wheel disc (10) and the fixed object (20) are pre-fastened with bolts (bolt_pretension).

[0135] STEP 2 of Table 1 shows the maximum bolt stress applied to the vehicle wheel disk (10) of Examples 1 and 2 and the conventional vehicle wheel disk (10) in a state where the vehicle wheel disk (10) and the fixed object (20) are completely fastened with bolts (bolt_fix).

[0136] Referring to STEP 1 and 2 of Table 1, it was found that there was no significant difference in the maximum bolt stress applied to the bolt between the vehicle wheel disc (10) of Examples 1 and 2 of the present invention and the conventional vehicle wheel disc (10).

[0137] Therefore, it was found that the maximum bolt stress applied to the bolt did not change according to the area of ​​the reference surface (V2) when the bolt was temporarily tightened (STEP 1) or when the bolt was fully tightened (STEP 2).

[0138] Table 2 below is the analysis result derived through structural analysis of the durability performance evaluation of the conventional vehicle wheel disc (10) and Examples 1 and 2 of the vehicle wheel disc (10) of the present invention by the durability performance evaluation method illustrated in Fig. 1.

[0139]

[0140] First, with regard to Table 2, the durability performance evaluation method illustrated in Fig. 1 is briefly described as follows.

[0141] As shown in Fig. 1, a conventional vehicle wheel disk (10) is bolted and connected to a fixed object (20) connected to an axle, and a wheel rim (30) connected to the vehicle wheel disk (10) is fixed to a rotating table (50).

[0142] Afterwards, durability performance can be evaluated by applying a moment load by rotating the rotating table (50) while applying a load in a direction perpendicular to the axle direction to the lower portion of the axle (40).

[0143] STEPs 1 to 30 in Table 2 are the results of a durability performance evaluation conducted while applying a moment load while the rotating table (50) rotated 12 degrees in 30 steps. This may mean that the durability performance evaluation was conducted under uniform conditions for the entire circumferential direction of the vehicle wheel disk (10) by rotating the vehicle wheel disk (10) 360 degrees in the circumferential direction.

[0144] X and Y of the load [N] in Table 2 represent the direction in which the load is applied. Specifically, the X direction may be the front-rear direction of the vehicle from the center portion of the fixed unit (100) of the vehicle wheel. The Y direction may be the up-down direction in which the tire touches the ground from the center portion of the fixed unit (100) of the vehicle wheel. Accordingly, the X direction (front-rear direction) and the Y direction (up-down direction) may be directions that intersect vertically while forming a 90-degree angle.

[0145] The loads are expressed separately in the X and Y directions because the loads are expressed as vectors. At this time, if you calculate the resultant force of the loads in the X and Y directions in STEPs 1 to 30, you can see that they are all 1837 N. The resultant force of the loads in STEPs 1 to 30 is all 1837 N.

[0146] When evaluating the durability of vehicle wheels, bolts can exhibit different stress distributions depending on their location. In Table 2, the maximum bolt stress [MPa] refers to the stress at the point where the greatest stress is applied among the stresses distributed across the bolt when evaluating the durability of vehicle wheels. Among steps 1 to 30, the highest maximum bolt stress is observed in step 26.

[0147] Referring to Table 2, it can be seen that there is no significant difference in the maximum bolt stress applied to the vehicle wheel disc (10) of Example 1 in STEPs 1 to 30. Of course, it can be seen that the same applies to the vehicle wheel disc (10) of Example 2 and the conventional vehicle wheel disc (10).

[0148] Therefore, it is sufficient to select and compare the result value in any one of STEPs 1 to 30. For example, if the result value in STEP 26, which has the highest maximum bolt stress among STEPs 1 to 30, is selected and compared, Example 1 has a maximum bolt stress of 481.8 MPa, Example 2 has a maximum bolt stress of 488 MPa, and the conventional method has a maximum bolt stress of 422 MPa.

[0149] It can be seen that Example 1 of the present invention has a bolt maximum stress of 481.8 MPa, which is a 14.2% increase in bolt maximum stress compared to the conventional case, and Example 2 of the present invention has a bolt maximum stress of 488 MPa, which is a 15.6% increase in bolt maximum stress compared to the conventional case.

[0150] That is, it can be seen that the vehicle wheel disc (10) of Examples 1 and 2 has a significantly increased maximum bolt stress compared to the conventional vehicle wheel disc (10). As such, the vehicle wheel disc (10) of Examples 1 and 2 has a significantly increased maximum bolt stress, and there is a concern that the disc wheel may break without the bolt breaking during the durability performance evaluation shown in Fig. 1. Therefore, it is necessary to appropriately set the area (V2) of the reference surface to prevent this.

[0151] In addition, when durability performance evaluation was performed on the vehicle wheel disc (10) of Examples 1 and 2 and the conventional vehicle wheel disc (10) using the durability performance evaluation method illustrated in FIG. 1, it was found that the maximum stress of the applied bolt significantly changed the result value depending on the area (V2) of the reference surface.

[0152] Therefore, the reference surface (P1) where the vehicle wheel disc (10) comes into contact with the fixed object (20) can be made smaller compared to the conventional vehicle wheel disc (10) with a shape designed as in Embodiments 1 and 2 of the present invention. Even when the reference surface (P1) where the vehicle wheel disc (10) comes into contact with the fixed object (20) becomes smaller as in Embodiments 1 and 2 of the present invention, it is necessary to appropriately set the area (V2) of the reference surface to prevent the bolt from loosening or breaking when evaluating the durability of the vehicle wheel disc (10).

[0153] The vehicle wheel disc (10) of the present invention has an area (V2) of a reference surface that is 20% or more of the area (V1) of a reference area (P), so that when evaluating the durability of the vehicle wheel disc (10), breakage or loosening of the bolts does not occur.

[0154] Accordingly, the vehicle wheel disc (10) of the present invention cannot secure a wide reference surface (P1) where the vehicle wheel disc (10) comes into contact with the fixed object (20) as in the past due to its designed shape, but has the effect of providing a vehicle wheel disc (10) that can satisfy the intended design shape within a range where bolts do not loosen or break when evaluating the durability of the vehicle wheel disc (10).

[0155] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible within a scope that does not depart from the technical spirit of the present invention described in the claims.

[0156] [Explanation of symbols]

[0157] 10: Vehicle wheel disc 11: Reference surface

[0158] 20: Fixed object 30: Wheel rim

[0159] 40: Axle 50: Rotating table

[0160] 100: Fixed unit 110: Fixed body

[0161] 111: Fixed hole 130: Fastening part

[0162] 131: Fastening hole 133: Fastening bead

[0163] 150: Hole frame 170: Fixed bead

[0164] 200: Spoke unit 210: Vent hole

[0165] 230: Spoke bead D: Axle direction

[0166] E: Radial

[0167] J: vertical plane K: inclined plane

[0168] P: Reference area P1: Reference plane

[0169] P2: First step surface Q: Second step surface

[0170] R: Separation distance S: Hole connection circle

[0171] T: Hole extension line V1: Area of ​​reference area

[0172] V2: Area of ​​the reference surface

Claims

1. Fixed unit; and A spoke unit formed to extend radially outward from the above fixed unit; The above fixed unit is, A fixed body having a fixing hole formed through the central portion; and It includes a plurality of fastening parts formed on the above fixed body and spaced apart from each other around the above fixed hole and capable of fastening to a fixed object; The imaginary circle connecting the center of the fastening holes of the above fastening part is called the hole connecting circle. When the area surrounded by the above-mentioned hole connection circle, the above-mentioned spoke unit and the above-mentioned fastening portion is called the reference area, The above fixed unit is, A vehicle wheel disc, comprising a reference surface that comes into contact with the fixed object in at least a portion of the reference area when installed on the fixed object.

2. In paragraph 1, The above reference surface is a vehicle wheel disk that comes into contact with the fixed object over the entire area of ​​the above reference area.

3. In paragraph 1, The above fixed unit is, The reference surface formed in a part of the above reference area and in contact with the fixed object; and A vehicle wheel disc comprising a first step surface formed in the remaining portion of the above reference area excluding the reference surface and not in contact with the fixed object.

4. In paragraph 3, The above fixed unit is, A vehicle wheel disc comprising a second step surface having at least a portion of a radially inner side of the hole connecting member that does not contact the fixed object.

5. In paragraph 1, The above fixed unit has a hole edge formed on the edge portion that contacts the above fixed hole, The above-mentioned fastening portion is a vehicle wheel disc installed to connect between the above-mentioned spoke unit and the above-mentioned hole frame.

6. In paragraph 1, A vehicle wheel disc, characterized in that the area of ​​the reference surface on a plane is 20% or more of the area of ​​the reference area.

7. In paragraph 4, A vehicle wheel disk wherein the first step surface and the second step surface have a distance of less than 1 mm from the fixed object in the axle direction.

8. In paragraph 1, The above reference surface is a vehicle wheel disc formed at a portion of the above reference area that is in contact with the connecting point where the spoke unit and the fastening portion are connected.

9. In paragraph 1, A vehicle wheel disc in which two of the above-mentioned reference areas are arranged with one of the above-mentioned fastening parts in between.

10. In paragraph 9, A vehicle wheel disc in which the reference area is arranged symmetrically based on a hole extension line, which is an imaginary extension line connecting the center part of the above-mentioned fixed hole and the center part of the above-mentioned fastening hole.

11. In paragraph 1, A vehicle wheel disc in which the spoke unit is formed such that at least a portion thereof extends to an inner area of ​​the hole connecting member or is positioned in contact with the hole connecting member.

12. In paragraph 1, The above spoke unit is, A vehicle wheel disc including a spoke bead that protrudes while covering a portion where the spoke unit and the fastening portion are in contact, or a portion where the spoke unit and the fastening portion are close to each other.

13. In paragraph 5, A vehicle wheel disc further comprising a fixed bead that connects the fastening portion and the spoke unit, or connects the fastening portion and the hole edge, in an inner area of ​​the hole connecting member.

14. In paragraph 1, A vehicle wheel disc in which the above fixed unit and the above spoke unit are made of steel.

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