Invention title: Center pillar inner and center pillar
Technical field
[0001]
　The present invention relates to an automobile center pillar inner.
Background technology
[0002]
　FIG. 1 is a diagram showing a general automobile body structure, and members such as a center pillar, a roof side rail, and a side sill are provided in a portion corresponding to a vehicle side surface. The upper end of the center pillar is joined to the roof side rail, and the lower end is joined to the side sill. The center pillar is required to have impact resistance to protect the occupants in the event of a side collision of an automobile, and technological development to improve the impact resistance has been promoted.
[0003]
　Patent Document 1 discloses that the inner member is made of CFRP (carbon fiber reinforced resin) among the outer member and the inner member constituting the center pillar. Patent Document 2 discloses that the outer member is made of aluminum and the inner member is made of CFRP. Patent Document 3 discloses that a reinforcing member made of CFRP is filled between the outer member and the inner member.
Prior art literature
Patent documents
[0004]
Patent Document 1: Japanese Patent Application Laid-Open No. 2013-221731
Patent Document 2: International Publication No. 2015/025572
Patent Document 3: Japanese Patent Application Laid-Open No. 2014-080183
Outline of the invention
Problems to be solved by the invention
[0005]
　When CFRP is applied as the inner member of the center pillar as in Patent Documents 1 and 2, the impact resistance required for the center pillar is not guaranteed because it is lighter than metal but has low elongation. Further, it is not preferable to use the inner member as it is as CFRP because the cost increases remarkably as compared with the case where metal is used.
[0006]
　Further, in recent years, it has been emphasized to reduce the weight of the vehicle in order to improve fuel efficiency. However, if a reinforcing member is filled between the outer member and the inner member as in Patent Document 3, the size of the reinforcing member becomes large. Is inevitable, leading to a further increase in weight. In the case of Patent Document 3, for example, it is conceivable to reduce the plate thickness of the inner member in order to reduce the weight of the vehicle, but this does not sufficiently secure the impact resistance of the center pillar.
[0007]
　The present invention has been made in view of the above circumstances, and an object of the present invention is to achieve both weight reduction and impact resistance of the center pillar while suppressing an increase in cost.
Means to solve problems
[0008]
　In order to solve the above problems, according to the present invention, an inner member having an opening as a mounting point for the retractor of the seat belt and a side sill mounting portion as a mounting point for the side sill is joined to the surface of the inner member. The CFRP member includes carbon fibers in the fiber direction within the range of −5 ° to 5 ° with respect to the longitudinal direction of the inner member, and the matrix resin is a thermoplastic resin. A center pillar inner is provided in which the CFRP member is provided at least between the opening and the side sill mounting portion.
[0009]
　According to the present invention from another viewpoint, the center pillar is provided with the center pillar outer and the center pillar inner described above, and the center pillar outer and the center pillar inner are joined to each other at a flange portion. Provided.
Effect of the invention
[0010]
　According to the present invention, it is possible to achieve both weight reduction and impact resistance of the center pillar while suppressing an increase in cost.
A brief description of the drawing
[0011]
[Fig. 1] Fig. 1 is a diagram showing a general automobile body structure.
FIG. 2 is a diagram showing a schematic configuration of a center pillar according to the first embodiment of the present invention.
FIG. 3 is an exploded view of a center pillar according to a first embodiment of the present invention.
FIG. 4 is a diagram showing an inner member of a center pillar according to the first embodiment of the present invention.
5 is a sectional view taken along the line AA in FIG. 2. FIG.
6 is a sectional view taken along the line BB in FIG. 2. FIG.
FIG. 7 is a diagram showing a schematic configuration of a center pillar according to a second embodiment of the present invention.
FIG. 8 is a diagram corresponding to the AA cross section in FIG. 2 of the center pillar according to the second embodiment of the present invention.
FIG. 9 is a diagram corresponding to a BB cross section in FIG. 2 of the center pillar according to the second embodiment of the present invention.
FIG. 10 is a diagram showing a schematic configuration of a center pillar according to a third embodiment of the present invention.
FIG. 11 is a diagram showing a schematic configuration of a center pillar according to a fourth embodiment of the present invention.
[Fig. 12] Fig. 12 is a diagram showing an analysis model of a side collision simulation in an example.
Embodiment for carrying out the invention
[0012]
　Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and the drawings, the elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.
[0013]

　As shown in FIG. 2, the center pillar 1 of the first embodiment is composed of a center pillar outer 10 and a center pillar inner 20. The center pillar outer 10 is a member made of, for example, a cold-rolled steel plate or a hot-stamped steel plate. As shown in FIGS. 2 and 3, the center pillar inner 20 is composed of an inner member 21 joined to the center pillar outer 10 and a CFRP member 22 joined to the inner member 21. The inner member 21 is, for example, a member made of a cold-rolled steel plate, a hot-stamped steel plate, a hot-rolled steel plate, or the like. The material constituting the center pillar outer 10 and the inner member 21 is not particularly limited as long as it is made of metal, and may be, for example, an aluminum alloy or the like. The CFRP member 22 is a member made of a carbon fiber reinforced resin in which carbon fibers are contained as a reinforced fiber resin in a predetermined matrix resin. The matrix resin and carbon fiber constituting the CFRP member will be described in detail later.
[0014]
　As shown in FIG. 4, the inner member 21 which is a component of the center pillar inner 20 has an opening 21a provided so that a retractor (winding device) of a seat belt can be attached, and a side sill 30 can be attached. It has a side sill mounting portion 21b provided in the above. The side sill mounting portion 21b corresponds to a portion of the inner member 21 when the inner member 21 and the side sill 30 are joined and covered with the side sill 30. Therefore, the opening 21a corresponds to the seatbelt retractor mounting location, and the side sill mounting portion 21b corresponds to the side sill 30 mounting location. The side sill mounting portion 21b of the first embodiment is formed in a planar shape so as to be in surface contact with the side sill 30, but the shape of the side sill mounting portion 21b is not particularly limited.
[0015]
　As shown in FIGS. 2 to 6, the shape from the lower side of the opening portion 21a of the inner member 21 to the upper end portion 21c is a hat shape in a cross-sectional view perpendicular to the height direction, and the flange portion 21d is formed. ing. The center pillar 1 is manufactured by joining the flange portion 21d of the inner member 21 and the flange portion 10a of the center pillar outer 10 having a hat shape similar to the inner member 21 to each other by spot welding, for example.
[0016]
　In the first embodiment, the CFRP member 22 is provided on the entire surface of the inner member 21. The shape of the CFRP member 22 is the same as the shape between the side sill mounting portion 21b and the upper end portion 21c of the inner member 21, and the CFRP member 22 is covered with, for example, the opening portion 21a of the inner member 21. A hole 22a (FIG. 3) having the same shape as the opening 21a is provided so that there is no such hole. The thickness of the CFRP member 22 is appropriately changed depending on the required impact resistance and weight limitation, but is preferably 1.0 to 4.0 mm, for example. Practically, it is preferably 1.0 to 2.0 mm.
[0017]
　The CFRP member 22 is joined to the inner surface of the inner member 21 on the inside of the vehicle. The method of joining the inner member 21 and the CFRP member 22 is not particularly limited, but the inner member 21 and the CFRP member 22 are joined by using, for example, an adhesive. Further, if the matrix resin of the CFRP member 22 is a thermoplastic resin, the CFRP member 22 may be heated and bonded to the inner member 21 by heat fusion. Therefore, for example, in the center pillar inner 20, after joining the inner member 21 and the center pillar outer 10, the CFRP member 22 is attached to the inner surface of the inner member 21 by using an adhesive or by heat fusion. Manufactured by attaching. When an adhesive is used, it can be confirmed by looking at the cross section of the center pillar inner 20 that the adhesive exists between the inner member 21 and the CFRP member 22.
[0018]
　Further, for example, in the center pillar inner 20, the CFRP member 22 whose shape is arranged so as not to cover the opening 21a of the blank is bonded or heat-sealed to the blank of the inner member 21 on which the opening 21a is formed. It is manufactured by joining by pressing and then pressing. When the inner member 21 and the CFRP member 22 are joined before the center pillar outer 10 and the center pillar inner 20 are joined, the spot welding dots of the center pillar outer 10 and the center pillar inner 20 are covered by the CFRP member 22. The CFRP member 22 is provided with a hole (not shown) in advance at a position corresponding to a spot welding spot position so as not to be in a broken state.
[0019]
　If the matrix resin of the CFRP member 22 is a thermoplastic resin, the bonding between the inner member 21 and the CFRP member 22 is compared with the case where a thermosetting resin is used by adhesive or heat fusion as described above. Then, it can be joined more firmly. As a result, even if an impact is applied to the center pillar inner 20 at the time of a side collision, the CFRP member 22 follows the deformation of the inner member 21, so that the effect of reinforcement is enhanced. Further, CFRP using a thermoplastic resin has a larger elongation than CFRP using a thermosetting resin (about 1 to 2%). Therefore, if the thermoplastic resin is applied to the CFRP member 22, the amount of work due to the pulling of the CFRP member 22 at the time of a side collision becomes larger than that when the thermosetting resin is used, so that the impact resistance is further improved. The specific joining method between the inner member 21 and the CFRP member 22 will be described later.
[0020]
　The center pillar inner 20 of the first embodiment and the center pillar 1 including the center pillar inner 20 are configured as described above. At the time of side collision, a compressive load is applied to the center pillar outer 10 and a tensile load is applied to the center pillar inner 20, but the center pillar inner 20 of the first embodiment is provided with the CFRP member 22. Therefore, the CFRP member 22 can receive the tensile load generated at the time of side collision. Since CFRP has excellent specific strength, it is possible to improve impact resistance while achieving weight reduction without increasing the strength of the inner member 21. Along with this, it becomes possible to use a metal such as a mild steel plate having high ductility for the inner member 21, and it is also possible to suppress the breakage of the center pillar inner 20 at the time of a side collision.
[0021]
　In this way, if the CFRP member 22 is joined to the inner member 21 to form the center pillar inner 20, the impact resistance of the center pillar 1 can be improved. In other words, by using the center pillar inner 20 of the first embodiment, sufficient impact resistance can be ensured even if the plate thickness of the inner member 21 is reduced for the purpose of reducing the weight of the vehicle. That is, it is possible to achieve both weight reduction and impact resistance of the center pillar 1. Further, in the center pillar inner 20 as in the first embodiment, it is possible to suppress an increase in cost as compared with the case where the entire inner member 21 is made of CFRP.
[0022]
　Further, if the amount of the CFRP member 22 is sufficient to be used for the center pillar inner 20, the inner member 21 and the CFRP member 22 are used when the center pillar inner 20 is reused as scrap, especially when the inner member 21 is a steel plate. Is not separated and can be smelted even if it is directly put into a converter of a steel mill and melted, so that impurities do not increase excessively. Therefore, the center pillar inner 20 to which the CFRP member 22 is joined to the inner member 21 is also excellent in recyclability.
[0023]

　As shown in FIGS. 7 to 9, the CFRP member 22 of the second embodiment is not provided on the entire surface of the inner member 21 as in the first embodiment, and the inner member is not provided. It is provided in the region between the opening portion 21a of the 21 and the side sill mounting portion 21b and in the entire flange portion 21d of the inner member 21. In the following description, the region between the opening portion 21a of the inner member 21 and the side sill mounting portion 21b is referred to as a “lower portion 21e” of the inner member 21.
[0024]
　At the time of a side collision, a large plastic strain is likely to occur in the lower portion 21e of the inner member 21 and the flange portion 21d on the side of the opening 21a, but the center pillar inner 20 of the second embodiment has the lower portion 21e and the flange. Since the CFRP member 22 is provided on the entire portion 21d, it is possible to effectively reinforce a portion that is easily deformed at the time of a side collision. That is, the flange portion 21d is a joint portion with the center pillar outer 10 and is a portion susceptible to an impact input to the center pillar outer 10. By providing the CFRP member 22 on the flange portion 21d, it is possible to suppress the deformation of the flange portion 21d according to the deformation of the center pillar outer 10 due to a side collision. As a result, the impact resistance of the center pillar inner 20 can be effectively improved. Therefore, if the center pillar inner 20 of the second embodiment is used, the amount of the CFRP member 22 used is reduced and the cost is reduced as compared with the case where the CFRP member 22 is provided on the entire surface of the inner member 21 as in the first embodiment. Sufficient impact resistance can be ensured while suppressing and reducing the weight.
[0025]

　As shown in FIG. 10, the CFRP member 22 of the third embodiment is provided on the lower portion 21e of the inner member 21 and the flange portion 21d'on the side of the opening portion 21a. As described above, the plastic strain of the inner member 21 generated at the time of a side collision tends to be large at the lower portion 21e and the flange portion 21d'on the side of the opening portion 21a, so that the CFRP member 22 opens as in the second embodiment. Even if the flange portion 21d'located above the portion 21a is not provided, if the CFRP member 22 is provided on the flange portion 21d'on the side of the opening 21a, the inner member 21 is effectively reinforced. be able to. Therefore, if the center pillar inner 20 of the third embodiment is used, the amount of the CFRP member 22 used is further reduced as compared with the center pillar inner 20 of the second embodiment, while cost reduction and weight reduction are achieved. Sufficient impact resistance can be ensured.
[0026]

　As shown in FIG. 11, the CFRP member 22 of the fourth embodiment is provided only on the lower portion 21e of the inner member 21. The plastic strain of the inner member 21 that occurs at the time of a side collision tends to be remarkably large in the lower portion 21e that is between the side sill mounting portion 21b and the opening portion 21a in the inner member 21. Therefore, even when the CFRP member 22 is provided only on the lower portion 21e as in the fourth embodiment, the inner member 21 can be effectively reinforced. Therefore, if the center pillar inner 20 of the fourth embodiment is used, sufficient impact resistance can be ensured while further reducing the weight of the center pillar inner 20 of the third embodiment, and the weight can be secured. The efficiency is even better.
[0027]
　As described in the first to fourth embodiments above, there are a plurality of embodiments for the joints of the CFRP member 22 to the inner member 21, but the weight reduction and impact resistance are suppressed while suppressing the increase in cost. From the viewpoint of achieving both, the CFRP member 22 needs to be provided at least in the lower portion 21e of the inner member 21 where the plastic strain is the largest at the time of a side collision.
[0028]
　Although the embodiments of the present invention have been described above, the present invention is not limited to such examples. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention also includes them. It is understood that it belongs to.
[0029]
　For example, in the first to fourth embodiments, the CFRP member 22 is joined to the inner surface of the inner member 21 on the inner side of the vehicle, but the CFRP member 22 may be joined to the outer surface of the inner member 21 on the outer side of the vehicle. .. That is, the CFRP member 22 may be provided between the center pillar outer 10 and the inner member 21. In this case, the center pillar inner 20 is manufactured by performing press molding in a state where the blank of the inner member 21 and the CFRP member 22 are previously joined. After that, the center pillar 1 is formed by joining the center pillar outer 10 and the center pillar inner 20 by, for example, spot welding. When spot welding is performed, the CFRP member 22 is provided with a hole (not shown) in advance at a position corresponding to the spot welding spot position so that the CFRP member 22 does not cover the spot welding spot of the inner member 21. Will be.
[0030]
　As described above, when the CFRP member 22 is provided between the center pillar outer 10 and the inner member 21, either the center pillar outer 10 or the center pillar inner 20 is provided with a hole for spot welding in the CFRP member 22. Processing such as providing a seat surface for spot welding is required. Therefore, since there is a concern that the processing cost will increase and the member rigidity will decrease due to processing, it is preferable that the portion where the CFRP member 22 is joined is the inner surface of the inner member 21.
[0031]
The CFRP
　member that can be attached to the inner member in each embodiment means a carbon fiber reinforced resin member made of a matrix resin and a carbon fiber material contained in the matrix resin and composited. do. As the carbon fiber, for example, PAN-based or pitch-based carbon fibers can be used. By using carbon fiber, it is possible to efficiently improve the strength against weight and the like. The CFRP used here has a carbon fiber content volume ratio of 50 to 70%, and the fiber direction of the carbon fiber is along the longitudinal direction of the center pillar inner (the center pillar inner is gently curved in the longitudinal direction). If so, it is preferable to follow the curve), and specifically, it is desirable that the fiber direction of the carbon fiber is within the range of −5 ° to 5 ° with respect to the direction. The orientation of the carbon fibers in the CFRP can be identified by observing and analyzing the CFRP member using a microfocus X-ray CT (X-ray Computed Tomography). It is preferable that the CFRP in that direction has a tensile strength of 1500 MPa or more, a Young's modulus of 102 GPa or more, and a breaking elongation of 1.5% or more.
[0032]
　As the matrix resin used for the CFRP member, a thermoplastic resin can be used. Examples of the thermoplastic resin include polyolefins (polyethylene, polypropylene, etc.) and acid-modified products thereof, polyamide resins such as nylon 6 and nylon 66, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, and polyether sulfone. , Polyphenylene ether and its modified products, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone, styrene resin such as vinyl chloride and polystyrene, and phenoxy resin. The matrix resin may be formed of a plurality of types of resin materials.
[0033]
　Considering the application to the metal member, the thermoplastic resin is used as the matrix resin from the viewpoint of workability and productivity, and from the viewpoint of following the deformation of the metal member due to the large tensile elongation. Furthermore, by using a phenoxy resin as the matrix resin, the density of the reinforcing fiber material can be increased, and the adhesion to the metal member and the followability to the deformation of the metal member are improved, resulting in CFRP. The peeling of the metal member is suppressed, energy absorption at the time of impact load input is efficiently performed, and the energy absorption capacity is improved. Further, since the phenoxy resin has a molecular structure very similar to that of the epoxy resin which is a thermosetting resin, it has the same heat resistance as the epoxy resin. Further, by further adding a curing component, it can be applied to a high temperature environment. When the curing component is added, the amount to be added may be appropriately determined in consideration of the impregnation property into the reinforcing fiber material, the brittleness of the FRP member, the tact time, the processability and the like.
[0034]

　When the reinforcing member is formed of a CFRP member or the like, an adhesive resin layer is provided between the CFRP member and the metal member (inner member 21 in the above embodiment), and the adhesive resin layer is used to form the CFRP member. It may be bonded to a metal member.
[0035]
　The type of the adhesive resin composition forming the adhesive resin layer is not particularly limited. For example, the adhesive resin composition may be either a thermosetting resin or a thermoplastic resin. The types of the thermosetting resin and the thermoplastic resin are not particularly limited. For example, examples of the thermoplastic resin include polyolefins and acid-modified products thereof, polystyrenes, polymethylmethacrylates, AS resins, ABS resins, thermoplastic aromatic polyesters such as polyethylene terephthalates and polybutylene terephthalates, polycarbonates, polyimides, polyamides and polyamides. Use one or more selected from imide, polyetherimide, polyethersulfone, polyphenylene ether and its modified products, polyphenylene sulfide, polyoxymethylene, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone and the like. can do. Further, as the thermosetting resin, for example, one or more selected from epoxy resin, vinyl ester resin, phenol resin, and urethane resin can be used.
[0036]
　The adhesive resin composition can be appropriately selected depending on the characteristics of the matrix resin constituting the CFRP member, the characteristics of the reinforcing member, or the characteristics of the metal member. For example, by using a resin having a polar functional group or an acid-modified resin as the adhesive resin layer, the adhesiveness is improved.
[0037]
　As described above, by adhering the CFRP member to the metal member using the above-mentioned adhesive resin layer, the adhesion between the CFRP member and the metal member can be improved. Then, when a load is input to the metal member, the deformation followability of the CFRP member can be improved. In this case, the effect of the CFRP member on the deformed body of the metal member can be more reliably exerted.
[0038]
　The form of the adhesive resin composition used for forming the adhesive resin layer can be, for example, a powder, a liquid such as varnish, or a solid such as a film.
[0039]
　Further, the crosslinkable adhesive resin composition may be formed by blending a crosslinkable curable resin and a crosslinking agent with the adhesive resin composition. As a result, the heat resistance of the adhesive resin composition is improved, so that it can be applied in a high temperature environment. As the crosslinkable curable resin, for example, a bifunctional or higher functional epoxy resin or a crystalline epoxy resin can be used. Further, as a cross-linking agent, an amine, an acid anhydride or the like can be used. Further, the adhesive resin composition may contain various additives such as various rubbers, inorganic fillers and solvents as long as the adhesiveness and physical characteristics are not impaired.
[0040]
　Composite of the CFRP member into a metal member is realized by various methods. For example, it can be obtained by adhering a CFRP molding prepreg which is a CFRP member or a precursor thereof and a metal member with the above-mentioned adhesive resin composition and solidifying (or curing) the adhesive resin composition. .. In this case, for example, the CFRP member and the metal member can be combined by performing heat crimping.
[0041]
　Adhesion of the above-mentioned CFRP or CFRP molding prepreg to a metal member may be performed before, during or after molding the part. For example, after molding a metal material to be processed into a metal member, CFRP or a CFRP molding prepreg may be bonded to the metal member. Further, after CFRP or a prepreg for CFRP molding is bonded to the work material by heat crimping, the work material to which the CFRP member is bonded may be molded to obtain a composite metal member. If the matrix resin of the CFRP member is a thermoplastic resin, it is also possible to perform molding such as bending on the portion to which the CFRP member is adhered. Further, when the matrix resin of the CFRP member is a thermoplastic resin, composite batch molding in which the heat crimping step and the molding step are integrated may be performed.
[0042]
　The method of joining the CFRP member and the metal member is not limited to the above-mentioned bonding by the adhesive resin layer. For example, the CFRP member and the metal member may be mechanically joined. More specifically, holes for fastening are formed at the corresponding positions of the CFRP member and the metal member, and these are fastened through the holes by fastening means such as bolts and rivets, whereby the CFRP member and the metal are fastened. It may be joined to the member. Alternatively, the CFRP member and the metal member may be joined by a known joining means. Further, the CFRP member and the metal member may be joined in a composite manner by a plurality of joining means. For example, the bonding by the adhesive resin layer and the fastening by the fastening means may be used in combination.
[0043]

　The metal member according to the present invention may be plated. This improves corrosion resistance. In particular, when the metal member is a steel material, it is more suitable. The type of plating is not particularly limited, and known plating can be used. For example, as plated steel sheets (steel materials), hot-dip galvanized steel sheets, hot-dip alloyed zinc-plated steel sheets, Zn-Al-Mg-based alloy-plated steel sheets, aluminum-plated steel sheets, electrogalvanized steel sheets, electric Zn-Ni-based alloy-plated steel sheets, etc. Can be used.
[0044]
　Further, the surface of the metal member may be coated with a film called chemical conversion treatment. This further improves the corrosion resistance. As the chemical conversion treatment, a generally known chemical conversion treatment can be used. For example, as the chemical conversion treatment, zinc phosphate treatment, chromate treatment, chromate-free treatment and the like can be used. Further, the film may be a known resin film.
[0045]
　Further, the metal member may be one having a generally known coating. This further improves the corrosion resistance. A known resin can be used for coating. For example, as the coating, an epoxy resin, a urethane resin, an acrylic resin, a polyester resin, a fluorine-based resin, or the like can be used as the main resin. Further, generally known pigments may be added to the coating, if necessary. Further, the coating may be a clear coating to which no pigment is added. Such coating may be applied to the metal member in advance before the CFRP member is composited, or may be applied to the metal member after the CFRP member is composited. Further, the CFRP member may be composited after the metal member has been painted in advance, and then the coating may be applied. The paint used for painting may be a solvent-based paint, a water-based paint, a powder paint, or the like. As a method of applying coating, a generally known method can be applied. For example, as a coating method, electrodeposition coating, spray coating, electrostatic coating, dip coating, or the like can be used. Electrodeposition coating is suitable for covering the end faces and gaps of metal members, and therefore has excellent corrosion resistance after coating. Further, by applying a generally known chemical conversion treatment such as zinc phosphate treatment or zirconia treatment to the surface of the metal member before painting, the adhesion to the coating film is improved.
Example
[0046]
　In order to evaluate the impact resistance due to the difference in the configuration of the center pillar inner, an analysis model as shown in FIG. 12 was created and a side collision simulation was carried out. The simulation conditions are based on the conditions of the side collision test of JNCAP (JAPAN New Car Assessment Program). Table 1 below shows the configuration of each center pillar for which side collision simulation was performed.
[0047]
[table 1]

[0048]
　The center pillar inner of Comparative Example 1 is composed of only a steel plate having a thickness of 0.95 mm and a tensile strength of 340 MPa. The center pillar inner of Comparative Example 2 is composed of only a steel plate having a thickness of 0.6 mm and a tensile strength of 340 MPa. The steel plate of Comparative Example 2 is a so-called thin steel plate having a thinner plate thickness than the steel plate of Comparative Example 1.
[0049]
　The center pillar inner of Example 1 has a configuration in which a CFRP member having a plate thickness of 2 mm is attached to the entire surface of the steel plate of Comparative Example 2 using an adhesive, and is the same as the first embodiment shown in FIG. It is a composition. The center pillar inner of Example 2 has a configuration in which a CFRP member having a plate thickness of 2 mm is attached to the entire lower portion and flange portion of the steel plate of Comparative Example 2 using an adhesive, and is shown in FIG. It has the same configuration as the embodiment. The center pillar inner of Example 3 has a configuration in which a CFRP member having a plate thickness of 2 mm is attached to the lower portion of the steel plate of Comparative Example 2 and the flange portion on the side of the opening by using an adhesive. It has the same configuration as the 4th embodiment shown in the above. The center pillar outer is common to each embodiment and is composed only of a hot stamped steel plate having a tensile strength of 1.5 GPa. Here, the matrix resins used in the CFRP members of Examples 1 to 3 are all phenoxy resins, which are thermoplastic resins. Further, the phenoxy resin and CFRP having a matrix resin used here have a carbon fiber content volume ratio of 50%, and the fiber direction of the carbon fibers is along the longitudinal direction of the center pillar inner (the center pillar inner is the longitudinal direction). If the curve is gently drawn, it should be along the curve). The tensile strength of CFRP in that direction was 1500 MPa, the Young's modulus was 102 GPa, and the elongation at break was 1.5%. The adhesive strength between the steel sheet and CFRP was analyzed with a shear fracture stress of 30 MPa.
[0050]
　Further, the center pillar inner of Comparative Example 3 has the same configuration as that of Example 1, and only the matrix resin used for the CFRP member is an epoxy resin which is a thermosetting resin. The center pillar inner of Comparative Example 4 has the same configuration as that of Example 2, and only the matrix resin used for the CFRP member is an epoxy resin which is a thermosetting resin. The center pillar inner of Comparative Example 5 has the same configuration as that of Example 3, and only the matrix resin used for the CFRP member is an epoxy resin which is a thermosetting resin. CFRP whose matrix resin is epoxy resin used in these comparative examples has a carbon fiber content volume ratio of 50%, and the fiber direction of the carbon fibers is along the longitudinal direction of the center pillar inner (the center pillar inner is in the longitudinal direction). If the curve is gently drawn, the fiber is along the curve), and the CFRP of the epoxy resin in that direction has a tensile strength of 1500 MPa, a Young ratio of 102 GPa, and a breaking elongation of 0.9%. The adhesive strength between the steel sheet and CFRP was analyzed with a shear fracture stress of 30 MPa.
[0051]
　The numerical values ​​in parentheses shown in the item of total weight in Table 1 indicate the difference from the total weight of the center pillar of Comparative Example 1.
[0052]
　In the side collision simulation conducted under the above conditions, the amount of penetration of the center pillar into the vehicle interior and the weight efficiency at the ground height corresponding to the chest and waist of the occupant were evaluated. In Table 2 below, the rate of change in the amount of pillar penetration (collision reduction in Table 2) and weight efficiency (collision reduction) in the center pillars of Comparative Examples 1, 3 to 5 and Examples 1 to 3 with respect to the center pillar of Comparative Example 2 are shown. / Weight increase) is shown.
[0053]
[Table 2]

[0054]
　As shown in Table 2, the center pillars of Examples 1 to 3 have improved weight efficiency regarding the collision reduction effect in both the chest and the waist as compared with the center pillar of Comparative Example 1 in which the plate thickness of the inner member is large. Further, in this simulation, the effect of improving the weight efficiency on the chest was the largest in Example 1, and the effect of improving the weight efficiency on the lumbar region was the largest in Example 2. Also in the third embodiment, the effect of improving the weight efficiency on the lumbar region is the same as that of the second embodiment, and the weight efficiency is excellent.
[0055]
　The center pillar of Example 1 does not have a large effect of weight reduction as compared with Comparative Example 1 in which the plate thickness of the inner member is large, but in view of the results shown in Table 2 above, the center pillar inner of Example 1 In the case of the configuration, it is presumed that sufficient impact resistance can be obtained even if the plate thickness of the inner member is further reduced. Therefore, it is possible to secure impact resistance equal to or higher than that of Comparative Example 1 while further reducing the weight. Therefore, if the center pillar inner of the first embodiment is used, both weight reduction and impact resistance can be achieved at the same time.
[0056]
　The collision reducing effect of the center pillar of Example 2 is at the same level as that of Comparative Example 1 in both the chest and the lumbar region, but the weight efficiency is improved. Therefore, if the center pillar inner of the second embodiment is used, both weight reduction and impact resistance can be achieved at the same time. Further, the collision reducing effect of the center pillar of Example 3 is that the impact resistance of the center pillar as a whole including the chest and the waist is at the same level as that of Comparative Example 1 in which the plate thickness of the inner member is large. Further, as shown in Table 2, the center pillar of Example 3 has a great effect of weight reduction as compared with Comparative Example 1 in which the inner member has a large plate thickness. Therefore, if the center pillar inner of the third embodiment is used, both weight reduction and impact resistance can be achieved at the same time. Further, in Example 3, since the effect of weight reduction is greater than that of Comparative Example 1, even if the plate thickness of the CFRP member is increased by, for example, about 0.1 mm to improve the impact resistance, it is compared with Comparative Example 1. The effect of weight reduction can be sufficiently obtained.
[0057]
　Further, the configuration of the center pillar inner of the third embodiment is such that the lower portion of the inner member and the CFRP member are provided on the flange portion on the side of the opening. However, in view of the result of the third embodiment, the side collision occurs. It is presumed that sufficient impact resistance can be obtained even when the CFRP member is provided only on the lower portion of the inner member where the plastic strain sometimes increases. Therefore, even if the CFRP member is a center pillar inner provided only in the lower portion of the inner member, both weight reduction and impact resistance can be achieved at the same time, and the cost of the material can be suppressed.
[0058]
　Further, when Examples 1 to 3 and Comparative Examples 3 to 5 were compared, Comparative Examples 3 to 5 had a low collision reducing effect in both the chest and the waist, and were significantly inferior in weight efficiency. This is because the thermosetting resin (epoxy resin) has a lower plastic deformability than the thermoplastic resin (phenoxy resin), and the CFRP member itself breaks during the collision and the CFRP peels off from the steel plate. be. As shown in Table 2, in Comparative Examples 3 to 5, the weight efficiency is about 1% or 1% or less, which is almost the same as that of Comparative Example 2 not reinforced by the CFRP member.
[0059]
　On the other hand, in Examples 1 to 3, a thermoplastic resin (phenoxy resin) is used as the CFRP member, and the CFRP member does not peel off or the CFRP member itself breaks during the collision, and exhibits excellent performance. I know.
[0060]
　That is, from the comparison between Examples 1 to 3 and Comparative Examples 3 to 5, the CFRP member to be attached to the center pillar inner is a phenoxy resin which is a thermoplastic resin rather than an epoxy resin which is a thermosetting resin. It turns out that is preferable.
[0061]
　At the time of a collision, the center pillar mainly positively plastically deforms the lower part (lower side of the vehicle body) to absorb energy. On the other hand, from the viewpoint of protecting the head and chest of the occupant on the upper side (upper side of the vehicle body) in the event of a collision, it is required to suppress the amount of the member invading the inside of the vehicle without actively deforming it. The deformation of the lower portion is mainly bending deformation, and the tensile force becomes higher toward the outside of the bending. Therefore, it is considered effective to arrange the CFRP member with high strength on the outside of the bend.
[0062]
　When a CFRP member having a high tensile force is placed outside the bend, applying a thermosetting resin having low ductility (for example, an epoxy resin) as the CFRP member is not preferable because the thermosetting resin breaks (Comparative Example 3). See ~ 5). On the other hand, when a highly ductile thermoplastic resin (for example, a phenoxy resin) is applied as a CFRP member, breakage is unlikely to occur, so energy absorption is efficiently performed. Based on the above findings and the comparison between Examples 1 to 3 and Comparative Examples 3 to 5, the ductility is high in order to exert the energy absorption effect predominantly by attaching the resin to the outside of the bend (that is, the vehicle body interior side). It is preferable to apply a thermoplastic resin (for example, a phenoxy resin) as a CFRP member.
Industrial applicability
[0063]
　The present invention can be used for the center pillar of an automobile.
Code description
[0064]
1 Center pillar
10 Center pillar outer
10a Center pillar outer flange
20 Center pillar inner
21 Inner member
21a Inner member opening
21b Inner member side sill mounting
21c Inner member upper end
21d Inner member flange
21d'Opening Side flange portion
21e Inner member lower portion
22 CFRP member
22a CFPR member hole
30 Side sill
The scope of the claims
[Claim 1]
The CFRP member comprises an inner member having an opening serving as a mounting portion for a retractor of the seat belt, a side sill mounting portion serving as a mounting portion for the side sill, and
　a CFRP member bonded to the surface of the inner member
　. It contains carbon fibers in the fiber direction within the range of −5 ° to 5 ° with respect to the longitudinal direction of the inner member, the matrix resin is a thermoplastic resin, and the
　CFRP member is at least the opening and the side sill mounting portion. Center pillar inner provided between and.
[Claim 2]
The center pillar inner according to claim 1, wherein the CFRP member is further provided on the flange portion of the inner member on the side of the opening.
[Claim 3]
The center pillar inner according to claim 2, wherein the CFRP member is further provided on a flange portion of the inner member located above the opening.
[Claim 4]
The center pillar inner according to any one of claims 1 to 3, wherein the thermoplastic resin is a phenoxy resin.
[Claim 5]
A center pillar comprising a center pillar outer and the center pillar inner according
　to any one of claims 1 to 4,wherein the center pillar outer and the center pillar inner are joined to each other at a flange portion.