Body structural members

Abstract

To provide a vehicle body structure member that is disposed on each of left and right sides of a body front part or body rear part and can exert energy absorption performance and rigidity retention performance against not only a collision in a fore-and-aft direction of a vehicle body but also a collision in an oblique direction.SOLUTION: A vehicle body structure member made of a fiber-reinforced resin and disposed at least in either a body front part or a body rear part includes a first member whose content percentage of continuous fibers, which are oriented in a fore-and-aft direction of a vehicle body and a vehicle width direction, out of contained continuous fibers exceeds 50%, and a second member whose content percentage of continuous fibers, which are oriented in a direction tilted leftward or rightward by a predetermined angle from the fore-and-aft direction of the vehicle body, that is, a direction oblique to each of the fore-and-aft direction of the vehicle body and the vehicle width direction, with respect to the contained continuous fibers exceeds 50%. The first member is disposed outside in the vehicle width direction, and the second member is disposed inside in the vehicle width direction. The first member and second member are joined.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle body structural member made of fiber-reinforced resin. [Background technology]

[0002] An automobile body structure includes front side members on both the left and right sides of the front of the vehicle in the vehicle width direction. In recent years, with the aim of reducing the vehicle body weight, it has been considered to manufacture some of the structural members constituting the vehicle body using fiber-reinforced resin containing reinforcing fibers such as carbon fiber. For example, Patent Document 1 proposes an energy-absorbing structure that can efficiently absorb energy during a vehicle collision while maintaining rigidity. Specifically, Patent Document 1 discloses a front side member in which energy-absorbing sections, each of which is a hollow member covered with a covering member, and rigidity-retaining sections are alternately arranged. The hollow member is made of a UD material in which reinforcing fibers are oriented in one direction along the extension direction of the front section. The covering members include a first covering member and a second covering member that forms the upper surface and the other side surface of the front section. The first covering member and the second covering member are made of fiber-reinforced resin using cross material oriented intersecting the extension direction of the front section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-001238 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the front side members described in Patent Document 1 are configured primarily for the purpose of absorbing energy and maintaining rigidity in a collision from the front in the longitudinal direction of the vehicle body (hereinafter also referred to as a "frontal collision"). Therefore, there is a risk that energy absorption will be insufficient in a collision from an oblique direction relative to the longitudinal direction of the vehicle body, such as an oblique collision or an offset collision, and the impact transmitted to vehicle occupants will not be reduced. It is also desirable for the rear side members provided on both the left and right rear sides of the vehicle body to adequately absorb energy and maintain rigidity in a collision from the rear in the longitudinal direction of the vehicle body (hereinafter also referred to as a "rear collision") and in a collision from an oblique direction.

[0005] Therefore, the present disclosure has been made in consideration of the above problems, and an object of the present disclosure is to provide a vehicle body structural member that is provided on both the left and right sides of the front or rear of the vehicle body and is capable of exhibiting energy absorption performance and rigidity retention performance not only in collisions from the fore-and-aft direction of the vehicle body but also in collisions from diagonal directions. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, according to one aspect of the present disclosure, there is provided a vehicle body structural member made of fiber-reinforced resin and provided in at least one of the front or rear of the vehicle body, the vehicle body structural member including: a first member having a content ratio of continuous fibers oriented along the vehicle body longitudinal direction and the vehicle width direction of greater than 50% among the continuous fibers; and a second member having a content ratio of continuous fibers oriented along directions inclined with respect to the vehicle body longitudinal direction and the vehicle width direction, and inclined at a predetermined angle to the left and right with respect to the vehicle body longitudinal direction, the first member being positioned on the outside in the vehicle width direction, and the second member being positioned on the inside in the vehicle width direction, and the first member and the second member being joined to each other. [Effects of the Invention]

[0007] As described above, according to the present disclosure, the cushions are provided on both the left and right sides of the front or rear of the vehicle body, and can exhibit energy absorption and rigidity retention performance not only in the event of a collision from the fore-and-aft direction of the vehicle body, but also in the event of a collision from an oblique direction. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a vehicle body front structure including a vehicle body structural member according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a perspective view of the structural member according to the embodiment, as viewed from the front side. [Figure 3] FIG. 2 is a plan view of the structural member according to the embodiment, as viewed from above. [Figure 4] 4 is a cross-sectional view of section II in FIG. 3 as viewed in the direction of the arrow. [Figure 5] FIG. 2 is a plan view of a first member and a second member of the structural member according to the embodiment, as viewed from above. [Figure 6] 10A and 10B are diagrams for explaining the function of the structural member according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0010] FIG. 1 is a schematic diagram of a vehicle front structure including vehicle body structural members (hereinafter also simply referred to as "structural members") 10L, 10R according to an embodiment of the present disclosure. The vehicle front structure shown in FIG. 1 includes structural members 10L, 10R joined to the left and right rear sides of a bumper beam 1. The structural members 10L, 10R are structural members formed from a fiber-reinforced resin composite material, and are joined to the bumper beam 1 at their front sides and to support members 3L, 3R at their rear sides. The support members 3L, 3R are not particularly limited as long as they are structural parts that support the structural members 10L, 10R at their rear sides, and may be structural members such as side members provided on the left and right sides, for example.

[0011] The structural members 10L, 10R and the bumper beam 1 or the support members 3L, 3R may be joined using, for example, an adhesive or fastening members such as bolts and nuts. The structural members 10L, 10R are located at the lower front of the vehicle body, with, for example, an internal combustion engine, a drive motor, a transmission, etc. located above them. The structural members 10L, 10R have the function of absorbing input energy in the event of a vehicle collision to mitigate the impact on vehicle occupants and maintaining rigidity to protect the occupants.

[0012] Figures 2 to 5 are diagrams for explaining a structural member 10L provided on the left side of the vehicle body front structure. Figure 2 is a perspective view of the structural member 10L seen from the front side, Figure 3 is a plan view of the structural member 10L seen from above, and Figure 4 is a cross-sectional view of section II in Figure 3 seen in the direction of the arrow. Figure 5 is a plan view of the first member 11 and the second member 13 seen from above.

[0013] The structural member 10L includes a first member 11, a second member 13, and a covering member 15. The first member 11, the second member 13, and the covering member 15 are each made of a fiber-reinforced resin composite material. Of these, at least the first member 11 and the second member 13 contain continuous fibers oriented in a predetermined direction. Examples of reinforcing fibers include carbon fiber, but other fibers may also be used, and a combination of multiple fibers may also be used. However, since carbon fiber has excellent mechanical properties, it is preferable that the reinforcing fibers include carbon fiber.

[0014] The matrix resin of the fiber-reinforced resin may be a thermoplastic resin or a thermosetting resin. Examples of thermoplastic resins include polyethylene resin, polypropylene resin, polyvinyl chloride resin, ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin), polystyrene resin, AS resin (acrylonitrile-styrene copolymer synthetic resin), polyamide resin, polyacetal resin, polycarbonate resin, polyester resin, PPS (polyphenylene sulfide) resin, fluororesin, polyetherimide resin, polyetherketone resin, and polyimide resin.

[0015] The matrix resin may be one of these thermoplastic resins or a mixture of two or more of them. Alternatively, the matrix resin may be a copolymer of these thermoplastic resins. When the thermoplastic resin is a mixture, a compatibilizer may be used in combination. Furthermore, a flame retardant such as a bromine-based flame retardant, a silicon-based flame retardant, or red phosphorus may be added to the thermoplastic resin.

[0016] Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenolic resins, polyurethane resins, and silicone resins. One or a mixture of two or more of these thermosetting resins can be used as the matrix resin. When using these thermosetting resins, an appropriate curing agent or reaction accelerator may be added to the thermosetting resin.

[0017] The first member 11 is disposed on the outer side in the vehicle width direction and is formed in a hollow cylindrical shape with a cross-sectional area that gradually decreases from the front side of the vehicle body to the rear side. That is, the first member 11 of the structural member 10L provided on the front left side of the vehicle body is disposed on the left side of the vehicle body. In the case of the structural member 10R provided on the front right side of the vehicle body, the first member 11 is disposed on the right side of the vehicle body. In this embodiment, the rear side of the first member 11 has a shape that forms an acute angle when viewed from above, but the rear side of the first member 11 may also be configured to have a thickness that provides a predetermined cross-sectional area. The first member 11 is configured so that the content ratio of continuous fibers oriented in the vehicle front-rear direction and the vehicle width direction, respectively, exceeds 50%.

[0018] For example, when forming the first member 11 by a layup method in which a plurality of fiber-reinforced resin sheets (prepregs) are laminated, the number of laminated fiber-reinforced resin sheets (cross material) containing continuous fibers oriented along the vehicle body longitudinal direction and vehicle width direction is designed so that the content ratio of continuous fibers oriented along the vehicle body longitudinal direction and vehicle width direction, respectively, exceeds 50%. Alternatively, when forming the first member 11 by a layup method, the arrangement direction and number of laminated fiber-reinforced resin sheets (UD material) containing continuous fibers oriented in one direction are designed so that the content ratio of continuous fibers oriented along the vehicle body longitudinal direction and vehicle width direction, respectively, exceeds 50%.

[0019] Among the continuous fibers contained in the first member 11, the content ratio of continuous fibers oriented along the vehicle body longitudinal direction and the vehicle width direction exceeds 50%. Therefore, the first member 11 has excellent strength characteristics against a load Fs in the vehicle body longitudinal direction, and also has excellent energy absorption characteristics against a load Fo applied in a diagonal direction relative to the vehicle body longitudinal direction (see FIG. 6).

[0020] The second member 13 is disposed on the inside in the vehicle width direction and is formed in a hollow cylindrical shape with its axial direction aligned with the vehicle front-rear direction. That is, the second member 13 of the structural member 10L provided on the front left side of the vehicle body is disposed to the right of the first member 11. In the case of the structural member 10R provided on the front right side of the vehicle body, the second member 13 is disposed to the left of the first member 11. The rear end of the second member 13 is supported by the support member 3L. In this embodiment, the cross-sectional area of ​​the second member 13 is constant from the front side to the rear side of the vehicle body, but the cross-sectional area may change along the way. The second member 13 is configured so that the content ratio of continuous fibers oriented in a direction inclined with respect to both the vehicle front-rear direction and the vehicle width direction and inclined at a predetermined angle to the left and right directions with respect to the vehicle front-rear direction exceeds 50%.

[0021] For example, when forming the second member 13 by a layup method in which multiple fiber-reinforced resin sheets (prepregs) are stacked, the number of fiber-reinforced resin sheets (cross material) containing continuous fibers oriented in directions inclined at a predetermined angle to the left and right relative to the longitudinal direction of the vehicle body is designed so that the content of continuous fibers oriented in directions inclined at a predetermined angle to the left and right relative to the longitudinal direction of the vehicle body exceeds 50%. Alternatively, when forming the second member 13 by a layup method, the arrangement direction and number of fiber-reinforced resin sheets (UD material) containing continuous fibers oriented in one direction are designed so that the content of continuous fibers oriented in directions inclined at a predetermined angle to the left and right relative to the longitudinal direction of the vehicle body exceeds 50%. The second member 13 may also be formed by a method in which continuous fibers impregnated with a matrix resin are wound around a jig, such as a filament winding method.

[0022] Of the continuous fibers contained in the second member 13, the content ratio of continuous fibers oriented in directions inclined at a predetermined angle to the left and right with respect to the longitudinal direction of the vehicle body exceeds 50%, so the second member 13 has excellent strength characteristics against a load Fo applied in an oblique direction with respect to the longitudinal direction of the vehicle body, and also has excellent energy absorption characteristics against a load Fs in the longitudinal direction of the vehicle body (see FIG. 6). Because the rear end side of the second member 13 is supported by the support member 3L, the energy absorption characteristics of the second member 13 can be effectively exhibited when a collision load is applied from the front of the vehicle.

[0023] The inclination angle of the continuous fibers contained in the second member 13, which are oriented along directions inclined at a predetermined angle to the left and right with respect to the longitudinal direction of the vehicle body, with respect to the longitudinal direction of the vehicle body, is preferably designed to be within a range of, for example, 30 to 45 degrees. This inclination angle affects how the vehicle collapses in response to an input load from the front of the vehicle body. This inclination angle also affects the strength characteristics with respect to an input load from the diagonally front left of the vehicle body. Therefore, the inclination angle may be designed so that the energy absorption characteristics with respect to an input load from the front of the vehicle body and the strength characteristics with respect to an input load from the diagonally front left of the vehicle body are desired. However, if the inclination angle is within a range of 30 to 45 degrees, both the energy absorption characteristics with respect to an input load from the front of the vehicle body and the strength characteristics with respect to an input load from the diagonally front left of the vehicle body can be exhibited in a balanced manner.

[0024] In this embodiment, the first member 11 has a quadrangular pyramid shape, and the second member 13 has a quadrangular prism shape. The first member 11 and the second member 13 are surface-bonded to each other. Furthermore, the first member 11 and the second member 13 are held together by being wrapped around them with a covering member 15. The covering member 15 may be a fiber-reinforced resin member containing continuous fibers, or a fiber-reinforced resin member containing short or long fibers. It may also be a resin member containing no reinforcing fibers. The energy absorption characteristics and load-bearing characteristics of the structural member 10 can be varied by appropriately designing the length or orientation direction of the fibers contained in the covering member 15.

[0025] Furthermore, because the first member 11 and the second member 13 are surface-joined to each other at a joint surface that extends in the vehicle height direction, when a collision load is received from the front left of the vehicle body, the first member 11 can be supported by the second member 13, which has high strength characteristics against loads from oblique directions. This helps prevent the first member 11 from being crushed axially, allowing the first member 11 to effectively exhibit its energy absorption characteristics.

[0026] Furthermore, in this embodiment, when structural member 10 is viewed in the height direction of the vehicle body, the outline 11a (see FIGS. 3 and 5) of first member 11 located on the outer side in the vehicle width direction moves inward in the vehicle width direction with increasing distance from the corner at the front left of the vehicle body, and the area of ​​the cross section perpendicular to outline 11a increases with increasing distance from the corner. Therefore, when a collision load is applied from the front left of the vehicle body, after first member 11 starts to collapse, it becomes easier for the corner side of first member 11 to gradually collapse, allowing first member 11 to effectively exhibit its energy absorption characteristics.

[0027] The structural member 10R provided on the right front side of the vehicle body is configured by inverting the structural member 10L provided on the left side, so that the structural member 10R can achieve the same effect as the structural member 10L.

[0028] The rear side members provided on the left and right rear sides of the vehicle body may also be configured in accordance with the configuration of structural members 10L, 10R. Specifically, the first member is disposed on the outer side in the vehicle width direction, and the second member is disposed on the inner side in the vehicle width direction. When the first member is viewed in the vehicle height direction, the outline of the first member located on the outer side in the vehicle width direction moves inward in the vehicle width direction as it moves away from the corner of the vehicle body, and the area of ​​the cross section perpendicular to the outline increases as it moves away from the corner. In other words, the configuration is the same as when the upper side of FIG. 1 is viewed as the rear side of the vehicle body.

[0029] As a result, the structural member made of fiber-reinforced resin installed at the rear of the vehicle body can exhibit excellent energy absorption characteristics against both collision loads from the rear of the vehicle body and collision loads from oblique directions, and can maintain a predetermined rigidity against both collision loads from the rear of the vehicle body and collision loads from oblique directions.

[0030] The space inside at least one of the first member 11 and the second member 13 may be filled with or placed with another member for increasing rigidity or for controlling energy absorption characteristics.

[0031] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to these examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these naturally fall within the technical scope of the present disclosure. Furthermore, combinations of the above-described embodiments and each modified example also naturally fall within the technical scope of the present disclosure. [Explanation of symbols]

[0032] 10·10L·10R: body structural member, 11: first member, 11a: outer periphery, 13: second member

Claims

1. A vehicle body structural member made of fiber reinforced resin and provided on both the left and right sides of at least one of the front and rear portions of the vehicle body, A first member in which the content ratio of continuous fibers oriented along the vehicle body longitudinal direction and the vehicle width direction exceeds 50% among the continuous fibers contained therein; a second member in which, among the continuous fibers contained therein, a content ratio of continuous fibers oriented along directions inclined at a predetermined angle to each of the vehicle body longitudinal direction and the vehicle width direction exceeds 50%, and the first member is disposed on the outer side in the vehicle width direction, the second member is disposed on the inner side in the vehicle width direction, The first member and the second member are joined to each other, When each of the vehicle body structural members is viewed in the height direction of the vehicle body, an outer contour line of the first member disposed on the outer side in the vehicle width direction moves inward in the vehicle width direction as it moves away from the corner side of the vehicle body, and A vehicle body structural member, wherein the area of ​​a cross section perpendicular to the outline increases with increasing distance from the corner.

2. 2. The vehicle body structural member according to claim 1, wherein the inclination angle of the continuous fibers contained in the second member and oriented along the direction inclined at the predetermined angle with respect to the vehicle body longitudinal direction is within a range of 30 to 45 degrees.

3. The vehicle body structural member according to claim 1 , wherein the first member and the second member each have a hollow cross section, and the first member and the second member are surface-joined to each other.

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