Lower cross member of vehicle

Abstract

The present invention discloses a lower cross beam of a vehicle. The lower cross beam comprises a core member, a lower layer and an upper layer, wherein the core member is configured to be arranged on a vehicle floor so as to extend in the width direction of the vehicle, is formed of a composite material comprising unidirectional carbon fiber or bidirectional carbon fiber, and has a cross section comprising at least one closed curve; the lower layer is configured to extend in the extension direction of the core member, is arranged between the core member and the vehicle floor, and is formed of a composite material comprising a first multi-axial glass fiber fabric; the upper layer is configured to extend in the extension direction of the core member, is arranged on the upper surface of the core member, and is formed of a composite material comprising a second multi-axial glass fiber fabric.

Description

Technical Field

[0001] The present invention relates to a lower cross member of a vehicle. Specifically, a novel seat cross member is provided herein, which can help increase load distribution, buckling resistance and rigidity, reduce the number of parts and the number of processes, and reduce weight and cost. Background Art

[0002] Among the performance factors of electric vehicles, the cruising range is an important factor for consumers when determining whether to purchase a vehicle. In particular, compared with hybrid electric vehicles (HEV) or fuel-cell electric vehicles (FCEV), battery electric vehicles (BEV) driven by batteries are not configured with a separate charging unit to charge the batteries during driving, and therefore, the cruising range is a very important performance factor. There are various methods of increasing the cruising range of BEVs, and fundamentally, a large number of batteries must be installed in order to ensure a sufficient cruising range. In this sense, for most electric vehicles, the battery is arranged under the passenger compartment.

[0003] However, if the battery is arranged in the lower part of the vehicle, the battery is subjected to impact force due to deformation of the vehicle body during a side collision, thereby causing a fire hazard. In order to prevent this problem, it is necessary to maintain sufficient collision space between the door sill of the vehicle body and the battery, and as the collision space increases, the battery capacity decreases in proportion to the increase in collision space, and the benefits of battery arrangement in the lower part of the vehicle may be lost. Therefore, the side collision performance of electric vehicles is not only simply used to protect passengers, but also plays an important performance factor in ensuring the cruising range.

[0004] Generally, as a strategy for coping with a side collision of an electric vehicle to protect the battery, as described below, the door sill area is set as an energy absorption space and the remaining interior space is set as a safety space. In order to effectively cope with a side collision, the energy absorption space must be deformed to the maximum extent to absorb the collision energy, while the deformation of the safety space must be minimized to avoid contact between the vehicle body and the battery. To this end, the interior cross member of the vehicle must have a sufficiently high strength so as not to deform during a side collision.

[0005] The above description is provided to help understanding the background of the present invention and should not be construed as conventional techniques known to those skilled in the art. Summary of the invention

[0006] Preferably, a novel lower cross member is provided that can help increase load distribution, buckling resistance and rigidity, reduce the number of parts and the number of processes, and reduce weight and cost.

[0007] In one aspect, provided is a lower cross member of a vehicle, comprising: (i) a core member configured to be arranged on a vehicle floor so as to extend in the width direction of the vehicle, formed of a composite material comprising unidirectional carbon fibers or bidirectional carbon fibers, and having a cross-section comprising at least one closed curve; (ii) a lower layer configured to extend in the extension direction of the core member, arranged between the core member and the vehicle floor, and formed of a composite material comprising a first multi-axial glass fiber fabric; (iii) an upper layer configured to extend in the extension direction of the core member, arranged on the upper surface of the core member, and formed of a composite material comprising a second multi-axial glass fiber fabric. The term "glass fiber fabric" as used herein may appropriately include a plurality of yarns containing glass filaments or fibers. Glass filaments and glass fibers may include a composite material of glass and non-glass materials, such as a glass-polyester blend or a glass-olefin composite material (e.g., St. Gobain's ) and other olefin coated C or E glass fibers and fiber fabrics. In addition, "glass" can be considered to be a molten inorganic product that has been cooled to a rigid condition without crystallization. For example, glass fibers can be suitably spun from a molten inorganic product that has been cooled to a rigid condition without crystallization.

[0008] As used herein, the term "multiaxial" refers to having directional properties along more than one axis. For example, a multiaxial fiber fabric may have strength (e.g., elongation, inherent strength, or primary tensile strength) along more than one axis (direction). Thus, a multiaxial fiberglass fabric as used herein may include glass fibers arranged in a number of directions, such as in bundles or groups, without limitation to the number of directions. Multi-axial fiberglass fabrics can be formed by arranging glass fibers in a random or irregular pattern or in directions at various angles, for example, ranging from ±5°, ±10°, ±15°, ±20°, ±25°, ±30°, ±35°, ±40°, ±45°, ±50°, ±55°, ±60°, ±65°, ±70°, ±75°, ±80°, ±85°, ±90°, ±95°, ±100°, ±105°, ±110°, ±115°, ±120°, ±125°, ±130°, ±135°, ±140°, ±145°, ±150°, ±155°, ±160°, ±165°, ±170°, ±175°, or ±180°.

[0009] The first and second multi-axial glass fiber fabrics can be of the same or different types. For example, if the first and second multi-axial glass fiber fabrics are different, the first multi-axial glass fiber fabric can have glass fiber fabrics arranged in a random or irregular pattern, and the second multi-axial glass fiber fabric can have fibers arranged in a pattern at different angles. Alternatively, both the first and second multi-axial glass fiber fabrics can be regular patterns, but the fibers in the patterns are in different orientations, for example, with at least 5 degrees, 10 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 60 degrees, 70 degrees, 80 degrees, or 90 degrees different between the respective patterns of the first and second multi-axial glass fiber fabrics.

[0010] The lower cross member may include at least one inner member configured to be coupled to the inner peripheral surface of the core member along a closed curve formed by a cross section of the core member, extending in an extending direction of the core member, and formed of a composite material including a third multi-axial glass fiber fabric.

[0011] The third multi-axial fiberglass fabric can be of the same type as at least one of the first and second multi-axial fiberglass fabrics, or of a different type than the first and second multi-axial fiberglass fabrics. For example, if the first and second multi-axial fiberglass fabrics are the same, such as both are non-random, and the fibers are arranged in the same orientation, the third multi-axial fiberglass fabric can have glass fibers arranged in a random or irregular pattern. Alternatively, the first, second, and third multi-axial fiberglass fabrics can be regular patterns, but the fibers in the patterns are in different orientations, for example, where there is a difference of at least 5 degrees, 10 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 60 degrees, 70 degrees, 80 degrees, or 90 degrees between the respective patterns of the first, second, and third multi-axial fiberglass fabrics.

[0012] The core member may include a horizontal portion, a reinforcement portion and an extension portion; the horizontal portion is connected to the upper surface of the lower layer; the reinforcement portion protrudes from the horizontal portion in an upward direction of the vehicle to form an internal space therein; the extension portion is configured to extend from the front and rear ends of the horizontal portion in the front-rear direction of the vehicle respectively, and the upper layer may be formed into a shape having the reinforcement portion and the extension portion covering the core member.

[0013] The core member may include a horizontal portion and a reinforcement portion, the horizontal portion being configured to be connected to the upper surface of the lower layer; the reinforcement portion being configured to protrude from the horizontal portion in an upward direction of the vehicle to form an internal space therein, and both ends of the lower layer and both ends of the upper layer extending in the front-rear direction of the vehicle may be connected to each other so as to surround the core member so that the lower layer and the upper layer are connected to the core member, and an internal member formed along a closed curve of the core member may be connected to the inner peripheral surface of the core member.

[0014] Each of the lower layer and the upper layer may be formed of a composite material including non-conductive glass fiber, aramid fiber, or polyethylene fiber.

[0015] At least one of the inner members may be formed from a composite material including multi-axial glass fibers, aramid fibers, or polyethylene fibers.

[0016] A support portion configured to extend in a direction intersecting an extending direction of the horizontal portion and to cross an internal space formed by the horizontal portion and the reinforcement portion may be provided between the horizontal portion and the reinforcement portion of the core member.

[0017] A plurality of mounting holes may be formed from an upper surface of the upper layer through the lower cross member in a vertical direction of the vehicle.

[0018] The core member may include a horizontal portion and a reinforcement portion, wherein the horizontal portion is configured to be connected to the upper surface of the lower layer; the reinforcement portion is configured to protrude from the horizontal portion in an upward direction of the vehicle to form an internal space therein, and a rib may be provided between the horizontal portion and the reinforcement portion of the core member, and is configured to be located adjacent to the mounting hole so as to increase the strength of the lower cross beam in the vertical direction of the vehicle and to cross the internal space formed by the reinforcement portion in a direction intersecting with the extension direction of the horizontal portion.

[0019] The ribs may be formed from a composite material including multi-axial glass fibers or unidirectional carbon fibers.

[0020] Flange portions configured to be bent upward from both ends of the lower layer extending in the front-rear direction of the vehicle so as to surround both ends of the core member and the upper layer extending in the front-rear direction of the vehicle may be formed.

[0021] A recessed portion configured to be depressed may be formed in an upper surface of the upper layer or a lower surface of the lower layer, and the recessed portion may extend in an extending direction of the upper layer or the lower layer.

[0022] A through hole may be formed through the lower cross member in the front-rear direction of the vehicle, and a component extending in the front-rear direction of the vehicle may pass through the lower cross member via the through hole.

[0023] A vehicle is also provided, comprising the lower cross member described herein.

[0024] Other aspects of the invention are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and other advantages of the present invention will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0026] Figure 1An exemplary lower cross member according to an exemplary embodiment of the present invention is shown;

[0027] Figure 2 shows the obtained along line AA Figure 1 sectional view of;

[0028] Figure 3 shows the obtained along line BB Figure 1 sectional view of;

[0029] Figure 4A Show description Figure 1 A perspective view of the front crossbeam;

[0030] Figure 4B shows the obtained along line CC Figure 4A sectional view of;

[0031] Figure 5A Show description Figure 1 A perspective view of the rear cross member;

[0032] Figure 5B shows the obtained along line DD Figure 5A sectional view of;

[0033] Fig. 6A and Figure 6B A cross-sectional view and an exploded perspective view illustrating an exemplary lower cross member according to an exemplary embodiment of the present invention are respectively shown.

[0034] Figures 7 to 9 A cross-sectional view illustrating an exemplary lower cross member according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0035] The specific structure or function description in the embodiment of the present invention set forth in the following description will be exemplarily given to describe the embodiment of the present invention. However, the present invention can be implemented in many alternative forms and should not be interpreted as being limited to the embodiment set forth herein.

[0036] Embodiments of the present invention may be variously modified and changed, so specific embodiments of the present invention will be shown in the accompanying drawings and described in detail in the following description of various exemplary embodiments of the present invention. However, these exemplary embodiments of the present invention are provided only to fully disclose the present invention and fully inform the technical personnel in the field of the scope of the present invention.

[0037] In the following description of the embodiment, it will be understood that when the terms "first", "second", etc. are used to describe various elements, these terms are not used to limit the elements. That is, these terms are only used to distinguish one element from other elements. For example, unless otherwise specified, within the technical scope of the present invention, a first element may be referred to as a second element, and similarly a second element may be referred to as a first element.

[0038] In the following description of the embodiments, it will be understood that when an element is "connected to," "coupled to," etc. another element, the two elements may be directly connected or coupled, or one or more other elements may be between the two elements. On the other hand, it will be understood that when an element is "directly connected to," "directly coupled to," etc. another element, no element may be between the two elements. In the following description of the embodiments, other terms representing the relationship between elements, such as "between" and "directly between" or "adjacent to" and "directly adjacent to." will be interpreted in the same manner.

[0039] It will be understood that the terms used in the following description of the embodiment are only used to describe specific embodiments and are not intended to limit the present invention, unless otherwise specified, the singular expression of an element covers the plural expression of the element. In the following description of the embodiment, the terms "including", "having", etc. will be interpreted as indicating the existence of the features, quantities, steps, operations, elements or parts stated in the specification, or a combination thereof, and do not exclude the existence of one or more features, quantities, steps, operations, elements, parts, or a combination thereof, or the possibility of adding them.

[0040] Unless otherwise stated or apparent from the context, as used herein, the term "about" is understood to be within the normal tolerance range in the art, such as within 2 standard deviations of the mean. "About" may be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the specified value. Unless the context clearly indicates otherwise, all numerical values ​​provided herein are modified by the term "about".

[0041] It should be understood that the term "vehicle" or "vehicle-based" or other similar terms used herein generally include motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, ships including various boats, vessels, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-fossil energy sources). As mentioned herein, a hybrid vehicle is a vehicle having two or more power sources, such as a vehicle having both gasoline power and electric power.

[0042] It will be understood that, unless otherwise defined, all terms (including technical or scientific terms) used in the following description of the embodiment have the same meaning as those generally understood by those skilled in the art. In addition, it will be explained that the terms defined in the general dictionary have the meaning consistent with the contextual meaning in the relevant technology, and unless explicitly defined, do not have an ideal or overly formal meaning.

[0043] Hereinafter, reference will be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. In the following description of the embodiments and the drawings, when the same or similar elements are described in different drawings, they are represented by the same reference numerals.

[0044] like Figures 1 to 3 as well as FIG. 4A to FIG. 5B As shown, a lower cross member 1000 of a vehicle according to an exemplary embodiment of the present invention includes: (i) a core member 100, which is arranged on a vehicle floor so as to extend in a width direction of the vehicle, is formed of a composite material including unidirectional carbon fibers or bidirectional carbon fibers, and has a cross-section including at least one closed curve; (ii) a lower layer 200, which is configured to extend in an extending direction of the core member 100, is arranged between the core member 100 and the vehicle floor, and is formed of a composite material including a first multi-axial glass fiber fabric; and (iii) an upper layer 300, which is configured to extend in an extending direction of the core member 100, is arranged on an upper surface of the core member 100, and is formed of a composite material including a second multi-axial glass fiber fabric.

[0045] The present invention provides a lower cross beam structure of a passenger compartment for satisfying the side collision performance of an electric vehicle (EV) in which a battery is installed in the lower part of the vehicle. During a side collision of an electric vehicle (EV), if a door sill seriously intrudes into the passenger compartment, the door sill hits the battery, causing serious safety problems such as fire. In conventional technology, since the lower cross beam of the passenger compartment is made of steel or aluminum, when a side collision occurs, the lower cross beam will be severely damaged and the door sill seriously intrudes into the passenger compartment. Therefore, in order to protect the battery, the space between the battery and the door sill must be sufficiently widened. However, in this case, the absolute size of the battery is reduced, and thus, the cruising range of the electric vehicle (EV) is reduced.

[0046] Therefore, in order to solve the above problems, this article provides a lower cross beam structure of a passenger compartment, which can minimize the intrusion of the door sill into the passenger compartment during a side collision, thereby ensuring the side collision stability by only utilizing the space between the battery and the door sill, and thereby maximizing the cruising range of the electric vehicle.

[0047] Among the performance factors of electric vehicles, the cruising range is an important factor for consumers when determining whether to purchase a vehicle. In particular, compared with a hybrid electric vehicle (HEV) or a fuel cell electric vehicle (FCEV), a battery electric vehicle (BEV) driven by a battery is not configured with a separate charging unit to charge the battery during driving, and therefore, the cruising range is a very important performance factor. There are various methods of increasing the cruising range of a BEV, and fundamentally, a large number of batteries must be installed in order to ensure a sufficient cruising range. In this sense, for most electric vehicles, the battery can be arranged under the passenger compartment.

[0048] However, if the battery is arranged in the lower part of the vehicle, the battery is subjected to impact force due to deformation of the vehicle body during a side collision, thereby causing a fire hazard. In order to prevent this problem, it is necessary to maintain a sufficient collision space between the door sill of the vehicle body and the battery, and as the collision space increases, the battery capacity decreases in proportion to this increase, thereby possibly losing the benefit of arranging the battery in the lower part of the vehicle.

[0049] Therefore, the side collision performance of electric vehicles is not only used to simply protect passengers, but also plays an important performance factor in ensuring the driving range. In order to effectively cope with side collisions, the energy absorbing part must be deformed maximally in order to absorb the collision energy, while the deformation of the safety space must be kept to a minimum in order to suppress the contact between the body and the battery. To this end, the vehicle's interior cross member must have a high enough strength not to deform during a side collision.

[0050] Therefore, the present invention provides a composite material including carbon fiber, glass fiber or resin as an anisotropic material applied to a vehicle interior cross beam, and the strength of the vehicle interior cross beam in each direction can be determined according to the needs of the designer.

[0051] For example, in order to increase the strength of the cross member in the width direction of the vehicle, the largest amount of unidirectional carbon fibers formed by extending the core member 100 may be arranged in the width direction of the vehicle.

[0052] However, when carbon fibers are arranged only in the width direction, the core member 100 may be easily broken when cracking occurs due to external contact in the front-rear direction or in the vertical direction, buckling, or load of the vehicle. Therefore, the upper layer 300 formed of a composite material including a second multi-axial glass fiber fabric may be arranged on the upper surface of the core member 100.

[0053] Furthermore, since the core member 100 is formed of carbon fiber, a lower layer 200 formed of a non-conductive material, which can block electrical conduction to vehicle body parts formed of other materials and prevent galvanic corrosion, may be disposed on a lower surface of the core member 100 .

[0054] In addition, at least one inner member 400 coupled to the inner circumferential surface of the core member 100 along a closed curve formed by the cross section of the core member 100 , extending in the extending direction of the core member 100 , and formed of a composite material including a third multi-axial glass fiber fabric may be provided.

[0055] The inner member 400 may have the same properties and functions as the upper layer 300, that is, may prevent the core member 100 from being easily broken when the core member 100 is slightly cracked due to external contact, buckling, or a load of a vehicle in the front-rear direction or a load of a vehicle in the vertical direction.

[0056] Therefore, if Figures 1 to 3 as well as FIG. 4A to FIG. 5B As shown, as the lower cross beam 1000, a plurality of front cross beams 1100 and a plurality of rear cross beams 1200 can be provided, which are made of the same material as described above to have the same structure. Since the front cross beam 1100 and the rear cross beam 1200 can have the same structure but different shapes, for the convenience of description, both the front cross beam 1100 and the rear cross beam 1200 are defined as the lower cross beam 1000.

[0057] like Figure 2 As shown, a through hole 1120 may be formed through the front cross member 1100 in the front-rear direction of the vehicle, and a component extending in the front-rear direction of the vehicle may pass through the inner space 410 formed in the front cross member 1100 via the through hole 1120 .

[0058] A sunken recess 1110 may be formed in the upper surface of the upper layer 300 or the lower surface of the lower layer 200 , and the recess 1110 may extend in an extending direction of the upper layer 300 or the lower layer 200 .

[0059] Preferably, the recess 1100 may more effectively absorb and support a side impact, and the recess 1100 may be formed adjacent to a path through which an air conditioning duct or an electric wire passing through the through hole 1120 passes.

[0060] In addition, if Figure 3 As shown, a plurality of mounting holes 1010 may be formed from an upper surface of the upper layer 300 through the rear cross member 1200 in a vertical direction of the vehicle.

[0061] That is, the rear cross beam 1200 may be coupled to a seat frame of the vehicle through the mounting hole 1010. A cross beam in a vehicle (such as a seat cross beam) needs to cope with high-strength installation such as seat installation. For example, only the mounting hole 1010 and the area of ​​the rear cross beam 1200 around the mounting hole 1010 need high strength, respectively, and therefore, the rear cross beam 1200 designed only to cope with collision loads may have difficulty coping with such high-strength installation.

[0062] To solve this problem, if the composition of the composite material of the rear beam 1200 is changed, the overall weight of the rear beam 1200 will increase. Therefore, a steel reinforcing plate may be further provided at the inner surface of the rear beam 1200 or at the area adjacent to the mounting hole 1010 on the upper surface of the rear beam 1200.

[0063] In addition, a rib 500 may be further provided, which is located adjacent to the mounting hole 1010 so as to increase the strength of the rear cross member 1200 in the vertical direction of the vehicle, and is provided between the horizontal portion 110 and the reinforcement portion 120 of the core member 100 so as to cross the internal space 410 formed by the reinforcement portion 120 in a direction intersecting with the extension direction of the horizontal portion 110.

[0064] As described above, the core member 100 may be formed of unidirectional carbon fiber or bidirectional carbon fiber, and each of the lower layer 200, the upper layer 300, and the rib 500 may include one or more layers formed of multi-axial glass fiber or resin. Preferably, the glass fiber may be woven by crossing wires at an angle of about +45° and at an angle of about -45°.

[0065] like Fig. 6A and Figure 6B As shown, in the lower cross member 1000 according to the exemplary embodiment of the present invention, the core member 100 may include a horizontal portion 110, a reinforcement portion 120, and an extension portion 130; the horizontal portion 110 is coupled to the upper surface of the lower layer 200; the reinforcement portion 120 protrudes from the horizontal portion 110 in the upward direction of the vehicle to form an internal space therein; the extension portion 130 extends from the front and rear ends of the horizontal portion 110 in the front-rear direction of the vehicle, respectively, and the upper layer 300 may be formed to have a shape having the reinforcement portion 120 and the extension portion 130 covering the core member 100. The extension portion 130 may extend from the horizontal portion 110 so as to prevent the horizontal portion 110 and the reinforcement portion 120 from being separated from each other in the front-rear direction of the vehicle when an external force is applied to the lower cross member 1000 in the vertical direction of the vehicle under the condition that the horizontal portion 110 and the reinforcement portion 120 are coupled.

[0066] In addition, the lower layer 200 may be installed between the core member 100 and the vehicle floor, and the inner member 400 installed on the inner circumferential surface of the core member 100 may be arranged along a closed curve formed by the cross section of the core member 100. The core member 100, the upper layer 300, the lower layer 200, and the inner member 400 may be coupled to form a trapezoidal support structure, thereby being able to provide a stronger supporting force.

[0067] like Figure 7As shown, in the stacking structure of the lower cross beam 1000 according to an exemplary embodiment of the present invention, the core member 100 may include a horizontal portion 110, a reinforcement portion 120 and an extension portion 130, the horizontal portion 110 being connected to the upper surface of the lower layer 200; the reinforcement portion 120 protruding from the horizontal portion 110 in the upward direction of the vehicle to form an internal space therein; the extension portion 130 extending from the front and rear ends of the horizontal portion 110 in the front-rear direction of the vehicle, respectively, and a rib 500 crossing the internal space 410 may be provided between the horizontal portion 110 and the reinforcement portion 120 of the core member 100.

[0068] The rib 500 may increase the rigidity of the core member 100 in the vertical direction of the vehicle.

[0069] Furthermore, one or more closed curves are formed in the core member 100 by the ribs 500 , so that the plurality of inner members 400 may be mounted on the inner circumferential surface of the core member 100 along the closed curve formed by the cross section of the core member 100 .

[0070] The core member 100 may be formed of a composite material including a conductive material, and thus a flange portion 210 may be formed that is bent upward from both ends of the lower layer 200 in the front-rear direction so as to surround both ends of the core member 100 and the upper layer 300 extending in the front-rear direction, thereby blocking electrical conduction to vehicle body parts formed of other materials and preventing galvanic corrosion.

[0071] like Figure 8 As shown, in the stacking structure of the lower cross beam 1000 according to an exemplary embodiment of the present invention, the core member 100 may include a horizontal portion 110, a reinforcement portion 120 and an extension portion 130, the horizontal portion 110 being connected to the upper surface of the lower layer 200; the reinforcement portion 120 protruding from the horizontal portion 110 in the upward direction of the vehicle to form an internal space therein; the extension portion 130 extending from the front and rear ends of the horizontal portion 110 in the front-rear direction of the vehicle, respectively, and a support portion 140 may be further provided between the horizontal portion 110 and the reinforcement portion 120 of the core member 100, the support portion 140 extending in a direction intersecting with the extension direction of the horizontal portion 110 and crossing the internal space 410 formed by the horizontal portion 110 and the reinforcement portion 120.

[0072] Furthermore, one or more closed curves are formed in the core 100 by the support portion 140 , so that the plurality of inner members 400 may be mounted on the inner circumferential surface of the core member 100 along the closed curve formed by the cross section of the core member 100 .

[0073] For example, the core member 100 may be formed of a composite material including a conductive material, and thus flange portions 210 may be formed that are bent upward from both ends of the lower layer 200 extending in the front-rear direction so as to surround both ends of the core member 100 and the upper layer 300 extending in the front-rear direction, thereby blocking electrical conduction to vehicle body parts formed of other materials and preventing galvanic corrosion.

[0074] In addition, the through hole 1120 formed through the lower cross member 1000 may extend to the support portion 140 or the rib 500, and the support portion 140 or the rib 500 may be cut into a region in which the through hole 1120 is formed so that an air conditioning duct or component extending in the front-rear direction of the vehicle passes through the through hole 1120.

[0075] like Fig. 9 As shown, in the stacking structure of the lower cross beam 1000 according to an exemplary embodiment of the present invention, the core member 100 may include a horizontal portion 110 and a reinforcement portion 120, the horizontal portion 110 being connected to the upper surface of the lower layer 200; the reinforcement portion 120 protrudes from the horizontal portion 110 in the upward direction of the vehicle to form an internal space therein, both ends of the lower layer 200 and both ends of the upper layer 300 extending in the front-rear direction of the vehicle may be connected to each other so as to surround the core member 100, and an internal member formed along a closed curve formed by a cross section of the core member 100 may be installed on the inner circumferential surface of the core member 100.

[0076] As a method for stacking the respective elements of the lower cross beam 1000 according to various exemplary embodiments of the present invention, the lower cross beam 1000 may be formed by stacking the horizontal portion 110 and the extension portion 130 connected to each other of the core member 100, stacking the inner member 400 on the upper surface of the horizontal portion 110 in sequence, stacking the reinforcement portion 120 on the upper surface of the inner member 400 so as to surround the inner member 400 and be connected to the horizontal portion 110 to form the core member 100, and stacking the upper layer 300 on the upper surface of the core member 100. Since the core member 100 is formed of unidirectional carbon fiber or bidirectional carbon fiber, the horizontal portion 110 and the reinforcement portion 120 may be easily stacked.

[0077] The lower cross member 1000 according to various exemplary embodiments of the present invention, which is formed of an anisotropic material so as to increase the strength of only a necessary portion thereof, can provide an excellent weight reduction effect compared to conventional technologies, is not deformed during a side collision so as to firmly protect a safety area, and helps to reduce the space required for a collision passing therethrough, thereby being able to secure additional battery capacity, thereby increasing the cruising range of the electric vehicle.

[0078] As is apparent from the above description, the lower cross member of a vehicle according to various exemplary embodiments of the present invention exhibits the following effects.

[0079] Compared to a conventional lower cross member formed of steel, the lower cross member of the present invention can achieve a weight reduction of about 48%, forms a closed cross section, and additionally includes ribs.

[0080] Furthermore, the lower cross member can be produced using inexpensive construction methods, so that there is no heavy burden on production costs due to the use of composite materials.

[0081] Furthermore, the lower cross member is hardly damaged during a side collision, thereby firmly protecting the safety space and reducing the necessary space therethrough to counter the side collision, thereby being able to secure additional battery capacity, thereby increasing the cruising range of the electric vehicle.

[0082] Although exemplary embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. A lower cross beam of a vehicle, comprising: a core member configured to be arranged on a vehicle floor so as to extend in a width direction of the vehicle, the core member being formed of a composite material including unidirectional carbon fibers or bidirectional carbon fibers and having a cross section including at least one closed curve; a lower layer configured to extend in an extending direction of the core member to be arranged between the core member and a vehicle floor, the lower layer being formed of a composite material including a first multi-axial glass fiber fabric; as well as an upper layer configured to extend in an extending direction of the core member to be arranged on an upper surface of the core member, the upper layer being formed of a composite material including a second multi-axial glass fiber fabric, wherein the core member comprises a horizontal portion, a reinforcement portion and an extension portion; the horizontal portion is configured to be coupled to an upper surface of a lower layer; the reinforcement portion is configured to protrude from the horizontal portion in an upward direction of the vehicle to form an internal space therein; the extension portion is configured to extend from a front end and a rear end of the horizontal portion in a front-rear direction of the vehicle, respectively, The upper layer is formed to have a shape covering the reinforcement portion and the extension portion of the core member.

2. The lower cross member of a vehicle according to claim 1, wherein: A support portion is provided between the horizontal portion and the reinforcement portion of the core member, the support portion being configured to extend in a direction intersecting an extending direction of the horizontal portion and to cross an inner space support portion formed by the horizontal portion and the reinforcement portion.

3. The lower cross member of the vehicle according to claim 1, further comprising at least one inner member configured to be coupled to the inner peripheral surface of the core member along a closed curve formed by a cross section of the core member to extend in an extending direction of the core member, the inner member being formed of a composite material including a third multi-axial glass fiber fabric.

4. The lower cross member of a vehicle according to claim 1, wherein: Each of the lower layer and the upper layer is formed of a composite material including non-conductive glass fiber, aramid fiber, or polyethylene fiber.

5. The lower cross member of a vehicle according to claim 3, wherein: At least one inner member is formed from a composite material including multi-axial glass fibers, aramid fibers, or polyethylene fibers.

6. The lower cross member of a vehicle according to claim 1, wherein: A plurality of mounting holes are formed from an upper surface of the upper layer through the lower cross member in a vertical direction of the vehicle.

7. The lower cross member of a vehicle according to claim 6, wherein: The core member includes a rib portion provided between the horizontal portion of the core member and the reinforcement portion, the rib portion being configured to be located adjacent to the mounting hole so as to increase the strength of the lower cross member in a vertical direction of the vehicle and to cross an inner space formed by the reinforcement portion in a direction intersecting an extending direction of the horizontal portion.

8. The lower cross member of a vehicle according to claim 7, wherein: The rib is formed of a composite material including multi-axial glass fibers or unidirectional carbon fibers.

9. The lower cross member of a vehicle according to claim 1, wherein: Flange portions configured to be bent upward from both ends of a lower layer extending in the front-rear direction of the vehicle are formed so as to surround both ends of the core member and the upper layer extending in the front-rear direction of the vehicle. 10 . The lower cross member of the vehicle according to claim 1 , further comprising a recessed portion configured to be sunken formed in an upper surface of the upper layer or a lower surface of the lower layer, wherein the recessed portion extends in an extending direction of the upper layer or the lower layer.

11. The lower cross member of a vehicle according to claim 1, wherein: A through hole is formed through the lower cross member in the front-rear direction of the vehicle, and a member extending in the front-rear direction of the vehicle passes through the lower cross member via the through hole.

12. A vehicle comprising the lower cross member of the vehicle according to claim 1.

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