JP6784493B2 - Lower arm - Google Patents

Description

The present invention relates to a fiber reinforced resin structure.

In recent years, fiber reinforced resins such as carbon fiber reinforced plastic (CFRP) have been used in various structures in order to improve the strength while reducing the weight. The fiber reinforced resin structure, which is a structure made of such a fiber reinforced resin, may include two or more fiber reinforced resin members. Then, in the field of a fiber reinforced resin structure including two or more fiber reinforced resin members, a technique for improving the mechanical properties of the fiber reinforced resin structure has been proposed.

For example, in Patent Document 1, the ends of a sandwich structure can be joined together easily and inexpensively without using a fastening member or the like, and sufficiently high strength and rigidity can be imparted to the joined portion, and the appearance is also improved. In order to provide an excellent sandwich structure, in a sandwich structure having a core material and FRP skin plates arranged on both sides thereof and butt-joining the ends, an FRP connecting layer extending over the surfaces of both ends is provided. , A technique of providing a layer containing a resin diffusion medium between the butt end faces is disclosed.

JP-A-2000-108232

By the way, as for the structural parts of an automobile body, components using a fiber reinforced resin such as carbon fiber reinforced resin (CFRP) are being used in order to reduce the weight of the body. For example, a fiber reinforced resin structure including two or more fiber reinforced resin members and having a joint portion between the fiber reinforced resin members can be applied to such a structural component of an automobile body. Here, a relatively large load that causes bending deformation may be input to the structural parts of the automobile body. When a structural part having a joint is bent and deformed, the tensile force or compressive force generated by the bending deformation may cause fracture starting from the joint, which is generally weak in strength. Therefore, when a fiber reinforced resin structure having a joint is applied to a structural part of an automobile body, it is considered desirable to improve the strength of the fiber reinforced resin structure against bending deformation.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved fiber reinforced resin structure capable of improving the strength against bending deformation. To do.

In order to solve the above problems, according to a certain viewpoint of the present invention, the lower arm including the upper member made of fiber reinforced resin and the lower member and mounted on the vehicle extends over the upper member and the lower member. The upper member and the reinforcing member extending along the joint portion of the lower member are provided, and the reinforcing member is a front side reinforcing member located on the front side of the vehicle body and a rear side located on the rear side of the vehicle body. The front side reinforcing member includes the reinforcing member, and the front side reinforcing member strengthens the rigidity in the direction of the tensile force applied to the vehicle body front side portion of the joint portion when the lower arm is bent and deformed, and the rear side reinforcing member. Strengthens the rigidity of the joint portion in the direction of the tensile force applied to the rear portion of the vehicle body when the lower arm is bent and deformed, and each of the upper member and the lower member is provided with a recess. A closed space is formed on the inner side of the lower arm by facing the recesses of the upper member and the lower member, and the reinforcing member is provided along the direction of the tensile force to form the closed space. A lower arm is provided that has a protruding portion that projects to the side . Further, the reinforcing member is provided over the upper member and the lower member, and further has a crossover portion extending along the joint portion, and the protrusion portion is from the crossover portion to the closed space side. It may protrude.

The reinforcing member may be a unidirectional fiber reinforced resin member in which reinforcing fibers are oriented along the direction of the tensile force.

The protrusions of the reinforcing member before Symbol junction, may be sandwiched between the upper member and the lower member.

The reinforcing member may be provided over the outer peripheral portion of the upper member and the lower member .

It includes a first base on the front side of the vehicle body and a second base on the rear side of the vehicle body supported by the vehicle body, and the front side reinforcing member is between the tip end portion of the lower arm and the first base portion at the joint portion. When the lower arm is bent and deformed along the portion of, the rigidity with respect to the direction of the tensile force applied to the portion between the tip portion of the lower arm and the first base portion at the joint portion is strengthened, and the rear portion The side reinforcing member is along the portion between the tip of the lower arm and the second base at the joint, and when the lower arm is bent and deformed, the tip of the lower arm and the second at the joint are formed. Rigidity in the direction of the tensile force applied to the portion between and the base of the

As described above, according to the present invention, it is possible to improve the strength against bending deformation in the fiber reinforced resin structure.

It is a schematic diagram which shows an example of the structure of the suspension system provided with the lower arm which concerns on embodiment of this invention. It is an exploded perspective view of a lower arm and a suspension cross member. It is a perspective view which shows an example of the lower arm which concerns on this embodiment. It is explanatory drawing for demonstrating the pulling force and compressive force applied to the joint part when bending deformation occurs in a lower arm. It is explanatory drawing for demonstrating the pulling force and compressive force applied to the joint part when bending deformation occurs in a lower arm. It is sectional drawing in the cross section substantially orthogonal to the vehicle width direction for demonstrating an example of the structure of the lower arm which concerns on a comparative example. It is sectional drawing in the cross section substantially orthogonal to the vehicle width direction for demonstrating an example of the structure of the lower arm which concerns on this embodiment. It is sectional drawing in the cross section substantially orthogonal to the vehicle width direction for demonstrating an example of the structure of the lower arm which concerns on a modification.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted. Further, in the present specification and the drawings, a plurality of components having substantially the same functional configuration may be distinguished by adding different alphabets after the same reference numerals. However, if it is not necessary to distinguish each of the plurality of components having substantially the same functional configuration, only the same reference numerals are given.

<1. Suspension device>
First, the suspension device 1 provided with the lower arm 20 of the vehicle corresponding to the fiber-reinforced resin structure according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic view showing an example of the configuration of the suspension device 1 for the front wheels of the vehicle provided with the lower arm 20, and FIG. 2 is an exploded perspective view of the lower arm 20 and the suspension cross member 8. Further, FIG. 3 is a perspective view showing an example of the lower arm 20.

As shown in FIG. 1, in the suspension device 1, the left and right sides of the engine room 2 are partitioned by a front wheel apron 3 which is a component of a vehicle body frame. The front wheel apron 3 is joined to a pair of left and right side frames 5 extending in the front-rear direction of the vehicle body. Further, a strut tower 6 is formed at the rear portion of the front wheel apron 3. A strut-type suspension 7 is housed in the strut tower 6. The upper part of the suspension 7 is supported by the strut support portion 6a formed on the upper part of the strut tower 6 via the strut upper mount 7a.

A suspension cross member 8 is arranged in the lower part of the engine room 2. The upper surfaces of both ends of the suspension cross member 8 in the vehicle width direction are fixed to the side frame 5 via fasteners such as bolts and nuts. Further, on the upper surface of the suspension cross member 8, a rear portion of an engine (not shown) is mounted via an engine mount. Further, arm support portions 9 are projected from the lower surfaces of both ends of the suspension cross member 8 in the vehicle width direction. As shown in FIG. 2, each of the left and right arm support portions 9 is provided with a pair of brackets 9a and 9b facing each other in front, back, left and right at predetermined intervals, and bolt insertion holes 9c are bored in the brackets 9a and 9b. ing. Between the brackets 9a and 9b, a tubular first base portion 21 provided at one base end of the lower arm 20 is arranged.

The lower arm 20 is continuous from the first base portion 21 which is one base end to the tip portion 23, and is continuous from the central portion and extends rearward to the second base portion 22 which is the other base end. It has a T-shaped or L-shaped planar shape. A cylindrical member (not shown) is press-fitted into the first base 21 of the lower arm 20. The shaft portion of the bolt 12 inserted from the outside is penetrated through the bolt insertion hole 9c bored in the brackets 9a and 9b, and the shaft portion of the bolt 12 is fastened by the nut 13. There is.

Further, a cylindrical member (not shown) is press-fitted into the second base portion 22. The second base portion 22 is pivotally supported by the side frame 5 via the cylindrical member. Further, a cylindrical member (not shown) is press-fitted into the tip portion 23 which is the swing end. The tip portion 23 is connected to a ball joint (not shown) via the cylindrical member, and a wheel hub (not shown) for fixing the front wheel 11 is rotatably supported. As a result, the lower arm 20 supports the lower portion of the suspension 7 via a hub housing (not shown) and is swingably supported by the suspension cross member 8 and the side frame 5.

As shown in FIG. 3, the lower arm 20 includes a first base portion 21 connected to the suspension cross member 8, a second base portion 22 connected to the side frame, and a tip portion 23 to which the ball joint is connected. Has. A cylindrical member 27 is press-fitted into the first base 21. A cylindrical member 28 is press-fitted into the second base 22. A cylindrical member 29 is press-fitted into the tip portion 23. The cylindrical member 27 press-fitted into the first tubular base 21 has a central axis that substantially coincides with the front-rear direction of the vehicle, and enables the tip portion 23 to swing in the vertical direction. Further, the cylindrical member 28 press-fitted into the second base portion 22 has a central axis along a substantially vertical direction, and enables the tip portion 23 to swing in the horizontal direction.

Further, the lower arm 20 according to the present embodiment is a fiber reinforced resin structure including two or more fiber reinforced resin members, and has a joint portion between the fiber reinforced resin members. Specifically, as shown in FIG. 3, the lower arm 20 is obtained by joining the upper member 210 and the lower member 220 at the joint portion 240. A recess is provided in each of the upper member 210 and the lower member 220, and when the recesses face each other, a closed space is formed on the inner side of the lower arm 20. When a member having a three-dimensional shape such as the lower arm 20 is molded by a fiber reinforced resin, it may be generally difficult to mold the member by press working. Therefore, as will be described later, the upper member 210 and the lower member 220 can be manufactured, for example, by bringing the laminated fiber-reinforced resin sheet into close contact with the molding surface of the molding die and curing it. In the upper member 210 and the lower member 220 manufactured in this way, the processing accuracy of the surface on the molding surface side is relatively high. Therefore, the lower arm 20 having a three-dimensional shape is manufactured by joining the portions of the upper member 210 and the lower member 220 manufactured in this manner on the opposite sides to the molding surfaces.

As will be described later, a relatively large load that causes bending deformation may be input to the lower arm 20 described above. When the lower arm 20 is bent and deformed, a tensile force and a compressive force are applied to the joint portion 240 of the lower arm 20. The lower arm 20 according to the present embodiment includes a reinforcing member (not shown) for strengthening the rigidity in the direction of the tensile force applied to the joint portion 240. As a result, according to the present embodiment, even when the lower arm 20 is bent and deformed, it is possible to prevent the occurrence of fracture starting from the joint portion 240. Hereinafter, after the bending deformation that occurs in the lower arm 20, the details of the lower arm 20 that can improve the strength against the bending deformation will be described.

<2. Lower arm ＞
(2-1. Bending deformation of lower arm)
First, the bending deformation that occurs in the lower arm 20 will be described with reference to FIGS. 4 to 6. 4 and 5 are explanatory views for explaining the tensile force and the compressive force applied to the joint portion 240 when the lower arm 20 is bent and deformed. 4 and 5 show a schematic view of the lower arm 20 shown in FIG. 3 as viewed from the upper member 210 side.

FIG. 4 shows a state in which a force facing the rear side of the vehicle body is applied to the tip portion 23. The arrow F10 in FIG. 4 indicates the direction of the force applied to the tip portion 23. As shown in FIG. 4, the force applied to the tip portion 23 has a component in the direction from the first base portion 21 to the second base portion 22. In the lower arm 20, the first base 21 and the second base 22 are fixed to the vehicle body. Therefore, as shown in FIG. 4, when a force toward the rear side of the vehicle body is applied to the tip portion 23, the lower arm 20 undergoes bending deformation such that the tip portion 23 bends toward the rear side of the vehicle body. As a result, a tensile force is applied to the portion 240a on the front side of the vehicle body of the joint portion 240 located between the tip portion 23 and the first base portion 21. On the other hand, a compressive force is applied to the portion 240b on the rear side of the vehicle body of the joint portion 240 located between the tip portion 23 and the second base portion 22.

FIG. 5 shows a state in which a force facing the front side of the vehicle body is applied to the tip portion 23. The arrow F20 in FIG. 5 indicates the direction of the force applied to the tip portion 23. As shown in FIG. 5, the force applied to the tip portion 23 has a component in the direction from the second base portion 22 to the first base portion 21. As shown in FIG. 5, when a force toward the front side of the vehicle body is applied to the tip portion 23, the lower arm 20 undergoes bending deformation such that the tip portion 23 bends toward the front side of the vehicle body. As a result, a compressive force is applied to the portion 240a on the front side of the vehicle body of the joint portion 240. On the other hand, a tensile force is applied to the portion 240b on the rear side of the vehicle body of the joint portion 240.

In the above, referring to FIGS. 4 and 5, the directions of the tensile force and the compressive force applied to the joint portion 240 of the upper member 210 and the lower member 220 in the bending deformation that occurs in the lower arm 20, and the joint portion 240. Although the example in which the extending directions of the above are substantially the same has been described, the directions of the tensile force and the compressive force may be different from the extending directions.

Here, unlike the lower arm 20 according to the present embodiment, the joint portion of the lower arm according to the comparative example not provided with the reinforcing member will be described. FIG. 6 is a cross-sectional view of a cross section substantially orthogonal to the vehicle width direction for explaining an example of the configuration of the lower arm 90 according to the comparative example. FIG. 6 shows a cross section at the tip of the lower arm 90 according to the comparative example, and is a cross section substantially orthogonal to the vehicle width direction at the tip 23 of the lower arm 20 shown in FIGS. 4 and 5. Correspond.

As shown in FIG. 6, the lower arm 90 according to the comparative example is a fiber reinforced resin structure obtained by joining the upper member 910 and the lower member 920, which are fiber reinforced resin members. The upper member 910 and the lower member 920 are joined by bringing the lower end of the upper member 910 and the upper end of the lower member 920 into contact with each other at the joint portion 940 and joining them with an adhesive. As the adhesive that can be used for joining the upper member 910 and the lower member 920, an epoxy resin-based adhesive, an acrylic resin-based adhesive, a urethane resin-based adhesive, or the like can be appropriately used. A recess 912 and a recess 922 are provided in each of the upper member 910 and the lower member 920, and the recess 912 and the recess 922 face each other to form a closed space 930 on the inner side of the lower arm 90. The portion 940a on the vehicle body front side of the joint portion 940 shown in FIG. 6 is located between the tip portion of the joint portion 940 and the first base portion. Further, the portion 940b on the rear side of the vehicle body of the joint portion 940 shown in FIG. 6 is located between the tip portion and the second base portion of the joint portion 940.

As described with reference to FIG. 4, in a state where a force toward the rear side of the vehicle body is applied to the tip end portion of the lower arm 90, a tensile force is applied to the portion 940a on the front side of the vehicle body of the joint portion 940 shown in FIG. A compressive force is applied to the front and rear portions 940b of the joint portion 940. Further, as described with reference to FIG. 5, in a state where a force toward the front side of the vehicle body is applied to the tip end portion of the lower arm 90, compression is applied to the portion 940a on the front side of the vehicle body of the joint portion 940 shown in FIG. A force is applied, and a tensile force is applied to the front and rear portions 940b of the joint portion 940.

In the comparative example, the strength against the tensile force and the compressive force applied to the joint portion 940 when the lower arm 90 is bent and deformed depends on the joint strength between the upper member 910 and the lower member 920 at the joint portion 940. Here, the joint strength at the joint portion of the two members becomes smaller as the contact area of the two members becomes smaller. Therefore, in the lower arm 90, when the contact area between the upper member 910 and the lower member 920 cannot be sufficiently secured, the pulling force or the compressive force generated by the bending deformation may cause the fracture starting from the joint portion 940.

(2-2. Configuration)
Subsequently, the configuration of the lower arm 20 according to the present embodiment will be described with reference to FIG. 7. FIG. 7 is a cross-sectional view of a cross section substantially orthogonal to the vehicle width direction for explaining an example of the configuration of the lower arm 20 according to the present embodiment. Specifically, FIG. 7 is a cross-sectional view taken along the line AA which is a cross section substantially orthogonal to the vehicle width direction at the tip portion 23 of the lower arm 20 according to the present embodiment shown in FIGS. 4 and 5.

As shown in FIG. 7, the lower arm 20 according to the present embodiment includes an upper member 210, a lower member 220, and a reinforcing member 250. The lower arm 20 corresponds to the fiber reinforced resin structure according to the present invention, which includes two or more fiber reinforced resin members. Further, the upper member 210 and the lower member 220 correspond to the fiber reinforced resin member according to the present invention.

Each of the upper member 210 and the lower member 220 can be manufactured by various manufacturing methods. For example, each of the upper member 210 and the lower member 220 is obtained by laminating a fiber-reinforced resin sheet in which reinforcing fibers are impregnated with a matrix resin on a molding surface of a molding mold made of, for example, metal or fiber-reinforced resin. By covering the reinforced resin laminate with a coating material and using a vacuum pump to reduce the pressure in the space between the coating material and the molding die, the fiber reinforced resin laminate is brought into close contact with the molding surface of the molding die and cured. , Manufactured.

Further, each of the upper member 210 and the lower member 220 is made by laminating a fiber reinforced resin sheet on a molding surface of a molding die, covering the obtained fiber reinforced resin laminate with a coating material, and forming the coating material and the coating material. By sending air or steam into the space between the fixing member fixed upward and pressurizing the space, the fiber reinforced plastic laminate is brought into close contact with the molding surface of the molding die via the covering material and cured. It may be manufactured by. The space between the covering material and the fixing member fixed above the covering material may be pressurized while being heated by using an autoclave device.

Further, each of the upper member 210 and the lower member 220 depressurizes the space between the covering material and the molding die, and pressurizes the space between the covering material and the fixing member fixed above the covering material. And, may be manufactured by performing in parallel.

The fiber-reinforced resin sheet used as a molding material is formed by impregnating reinforcing fibers with a matrix resin. The reinforcing fibers used are not particularly limited, and may be, for example, carbon fibers, glass fibers, aramid fibers, or the like, and further, these reinforcing fibers may be used in combination. Among them, it is preferable that the reinforcing fiber contains carbon fiber because the carbon fiber has high mechanical properties and the strength can be easily designed.

The reinforcing fiber may be a continuous fiber continuous from one end to the other end of the fiber reinforced resin sheet, or may be a short fiber shorter than the length from one end to the other end of the fiber reinforced resin sheet. In addition, continuous fiber and short fiber may be mixed in one fiber reinforced resin sheet. The fiber-reinforced resin sheet laminated in the manufacturing process of the upper member 210 and the lower member 220 may include a fiber-reinforced resin sheet in which the fibers are oriented in one direction, and the reinforcing fibers are arranged in a plurality of directions. A fiber reinforced resin sheet may be included. By aligning the orientation directions of the reinforcing fibers of the fiber-reinforced resin sheets, the strength of the obtained upper member 210 or lower member 220 with respect to the orientation direction can be effectively improved. Further, by making the orientation direction of the reinforcing fibers of at least one fiber-reinforced resin sheet of the laminated fiber-reinforced resin sheets different, the strength of the obtained upper member 210 or lower member 220 is made anisotropic. be able to.

Further, a thermoplastic resin or a thermosetting resin is used as the matrix resin of the fiber reinforced resin sheet. Examples of the thermoplastic resin include polyethylene resin, polypropylene resin, polyvinyl chloride resin, ABS resin, polystyrene resin, AS resin, polyamide resin, polyacetal resin, polycarbonate resin, thermoplastic polyester resin, PPS (polyphenylene sulfide) resin, and fluorine. Examples thereof include resins, polyetherimide resins, polyether ketone resins, and polyimide resins.

As the matrix resin, one kind or a mixture of two or more kinds of these thermoplastic resins can be used. Alternatively, the matrix resin may be a copolymer of these thermoplastic resins. Further, when the matrix resin is used as a mixture of these thermoplastic resins, a compatibilizer may be used in combination. Further, the matrix resin may contain a brominated flame retardant as a flame retardant, a silicon flame retardant, red phosphorus and the like.

In this case, examples of the thermoplastic resin used include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyether ketones. Examples thereof include resins such as polyether sulfone and aromatic polyamide. Among them, the thermoplastic matrix resin is preferably at least one selected from the group consisting of polyamide, polyphenylene sulfide, polypropylene, polyetheretherketone and phenoxy resin.

Examples of the thermosetting resin that can be used as the matrix resin include epoxy resin, unsaturated polyester resin, vinyl ester resin, phenol resin, polyurethane resin, and silicon resin. As the matrix resin, one kind or a mixture of two or more kinds of these thermosetting resins can be used. When these thermosetting resins are used in the matrix resin, an appropriate curing agent or reaction accelerator may be added to the thermosetting resin.

The fiber-reinforced resin sheet is produced, for example, by a process such as a general film impregnation method or a melt impregnation method, in which the reinforcing fibers are impregnated with the matrix resin while continuously delivering the reinforcing fibers. By cutting this fiber-reinforced resin sheet to a desired size, a fiber-reinforced resin sheet as a molding material can be obtained. The widthwise ends of the plurality of fiber-reinforced resin sheets cut to a desired size may be joined to each other with an adhesive or the like to form a fiber-reinforced resin sheet having a desired width and length. The thickness of the fiber reinforced resin sheet can be, for example, a value in the range of 0.03 to 1 mm.

The upper member 210 and the lower member 220 are joined either directly or via other members. For example, the upper member 210 and the lower member 220 are joined by bringing the lower end of the upper member 210 and the upper end of the lower member 220 into contact with each other at the joint portion 240 and joining them with an adhesive. .. As the adhesive that can be used for joining the upper member 210 and the lower member 220, an epoxy resin-based adhesive, an acrylic resin-based adhesive, a urethane resin-based adhesive, or the like can be appropriately used. In the joining between the members using the adhesive described below, the above-mentioned adhesive exemplified as an adhesive that can be used for joining the upper member 210 and the lower member 220 can be appropriately used. A recess 212 and a recess 222 are provided in each of the upper member 210 and the lower member 220, and the recess 212 and the recess 222 face each other to form a closed space 230 on the inner side of the lower arm 20.

As shown in FIG. 7, the reinforcing member 250 is provided over the upper member 210 and the lower member 220, and extends along the joint portion 240 of the upper member 210 and the lower member 220. The reinforcing member 250 is, for example, a member made of a fiber reinforced resin, and may be manufactured by the same manufacturing method as the upper member 210 and the lower member 220. Specifically, the reinforcing member 250 is provided from the side surface of the lower end portion of the upper member 210 to the side surface of the upper end portion of the lower member 220, and is joined to the upper member 210 and the lower member 220. For example, the reinforcing member 250 is joined to the side surface of the lower end portion of the upper member 210 and the side surface of the upper end portion of the lower member 220 by using an adhesive.

In the lower arm 20 according to the present embodiment, the upper member 210 and the lower member 220 are joined by providing the reinforcing member 250 which is provided over the upper member 210 and the lower member 220 and extends along the joint portion 240. The bonding area between members that contributes to strength can be increased. Therefore, the joint strength between the upper member 210 and the lower member 220 can be increased.

Further, the reinforcing member 250 strengthens the rigidity in the direction of the tensile force applied to the joint portion 240 of the upper member 210 and the lower member 220 when the lower arm 20 is bent and deformed. Specifically, the reinforcing member 250 according to the present embodiment is a unidirectional fiber reinforced resin member in which the reinforcing fibers are oriented along the direction of the tensile force applied to the joint portion 240. Here, by aligning the orientation directions of the reinforcing fibers contained in the fiber-reinforced resin member, the tensile strength of the fiber-reinforced resin member with respect to the orientation direction can be effectively improved. Therefore, by using the unidirectional fiber reinforced resin member in which the reinforcing fibers are oriented along the direction of the tensile force applied to the joint portion 240 as the reinforcing member 250, the rigidity with respect to the direction of the tensile force applied to the joint portion 240 is increased. Can be strengthened.

Specifically, the front side reinforcing member 250a, which is a reinforcing member 250 located on the front side of the vehicle body, enhances the rigidity of the joint portion 240 in the direction of the tensile force applied to the portion 240a on the front side of the vehicle body. Further, the rear side reinforcing member 250b, which is a reinforcing member 250 located on the rear side of the vehicle body, enhances the rigidity of the joint portion 240 in the direction of the tensile force applied to the portion 240b on the rear side of the vehicle body.

As a result, as shown in FIG. 4, when a force toward the rear side of the vehicle body is applied to the tip portion 23 of the lower arm 20, the lower arm 20 is deformed by the pulling force applied to the portion 240a on the front side of the vehicle body of the joint portion 240. Can be suppressed by the front side reinforcing member 250a. Further, as shown in FIG. 5, when a force toward the front side of the vehicle body is applied to the tip portion 23 of the lower arm 20, the lower arm 20 is deformed by the pulling force applied to the portion 240b on the rear side of the vehicle body of the joint portion 240. , It can be suppressed by the rear side reinforcing member 250b. Therefore, the strength of the lower arm 20 against bending deformation can be improved. Therefore, even when the lower arm 20 is bent and deformed, it is possible to prevent the occurrence of fracture starting from the joint portion 240. In this way, tensile forces can be generated at different positions in the joint portion 240 depending on the direction of the load input to the lower arm 20. In the present embodiment, as described above, the reinforcing member 250 is provided at a position where a tensile force is generated at the joint portion 240 in each of the load input directions to the lower arm 20. As a result, bending deformation of the lower arm 20 can be appropriately suppressed according to the direction of the load input to the lower arm 20.

Further, as shown in FIG. 7, the reinforcing member 250 may be provided over the outer peripheral portions of the upper member 210 and the lower member 220. Specifically, a recessed portion 214 and a recessed portion 224 recessed toward the inside of the lower arm 20 are provided at the lower portion of the outer peripheral portion of the upper member 210 and the upper portion of the outer peripheral portion of the lower member 220, respectively, and the upper member 210 and the lower portion are provided. In the state where the member 220 is joined, the recessed portion 214 and the recessed portion 224 are adjacent to each other. The reinforcing member 250, for example, can be joined to the upper member 210 and the lower member 220 in a state of being installed in the recess space formed by the recess portion 214 and the recess portion 224.

The shape of the recessed space formed by the recessed portion 214 and the recessed portion 224 may be a shape corresponding to the shape of the reinforcing member 250. For example, when the shape of the reinforcing member 250 is a band shape, the shape of the recessed space may be a groove shape having a slightly larger width direction than the reinforcing member 250. As a result, the reinforcing member 250 can be more easily positioned when the reinforcing member 250 is adhered to the upper member 210 and the lower member 220.

Generally, when a bending deformation occurs in an object, the position where the maximum tensile stress is applied in the object is the surface layer portion of the object. Therefore, when the reinforcing member 250 is provided over the outer peripheral portions of the upper member 210 and the lower member 220, when the lower arm 20 is bent and deformed, the outer peripheral portion is a position where a relatively large tensile force can be generated in the lower arm 20. Strength can be improved. Therefore, the strength of the lower arm 20 against bending deformation can be improved more effectively.

<3. Modification example>
In the above, by using the unidirectional fiber reinforced resin member in which the reinforcing fibers are oriented along the direction of the tensile force applied to the joint portion 240 as the reinforcing member 250, the rigidity with respect to the direction of the tensile force applied to the joint portion 240 I explained an example of strengthening. In the following, with reference to FIG. 8, the direction of the tensile force applied to the joint 340 by using the reinforcing member 350 provided with the protrusion 354 along the direction of the tensile force applied to the joint 340. An example of modification for strengthening the rigidity against the vehicle will be described.

FIG. 8 is a cross-sectional view of a cross section substantially orthogonal to the vehicle width direction for explaining an example of the configuration of the lower arm 30 according to the modified example. FIG. 8 shows a cross section at the tip of the lower arm 30 according to the modified example, and is a cross section substantially orthogonal to the vehicle width direction at the tip 23 of the lower arm 20 shown in FIGS. 4 and 5. Correspond.

As shown in FIG. 8, the lower arm 30 according to the modified example includes an upper member 310, a lower member 320, and a reinforcing member 350. The lower arm 30 corresponds to the fiber reinforced resin structure according to the present invention, which includes two or more fiber reinforced resin members. Further, the upper member 310 and the lower member 320 correspond to the fiber reinforced resin member according to the present invention.

Each of the upper member 310 and the lower member 320 can be manufactured by the same manufacturing method as the upper member 210 and the lower member 220 of the lower arm 20 described with reference to FIG. 7. In the modified example, the upper member 310 and the lower member 320 are joined via the reinforcing member 350. A recess 312 and a recess 322 are provided in each of the upper member 310 and the lower member 320, and the recess 312 and the recess 322 face each other to form a closed space 330 on the inner side of the lower arm 20.

As shown in FIG. 8, the reinforcing member 350 includes a crossover portion 352 and a protrusion portion 354. In the following, the crossing portion and the protrusion portion of the front side reinforcing member 350a, which is the reinforcing member 350 located on the front side of the vehicle body, will be referred to as a crossing portion 352a and the protrusion portion 354a, respectively, and the reinforcing member 350 is located on the rear side of the vehicle body. The crossovers and protrusions of the rear reinforcing member 350b are referred to as crossovers 352b and protrusions 354b, respectively.

The reinforcing member 350 is different from the reinforcing member 250 described with reference to FIG. 7 in that it includes a protrusion 354. The reinforcing member 350 is, for example, a member made of a fiber reinforced resin. The crossover portion 352 is provided over the upper member 310 and the lower member 320, and extends along the joint portion 340 of the upper member 310 and the lower member 320. Specifically, the crossover portion 352 is provided from the side surface of the lower end portion of the upper member 310 to the side surface of the upper end portion of the lower member 320, and is joined to the upper member 310 and the lower member 320. The crossover portion 352 is joined to, for example, the side surface of the lower end portion of the upper member 310 and the side surface of the upper end portion of the lower member 320 by using an adhesive.

In the lower arm 30 according to the modified example, the lower arm 20 is provided with reference to FIG. 7 by providing a crossing portion 352 provided over the upper member 310 and the lower member 320 and extending along the joint portion 340. Similarly, the bonding area between the members that contributes to the joint strength between the upper member 310 and the lower member 320 can be increased. Therefore, the joint strength between the upper member 310 and the lower member 320 can be increased.

Further, the crossover portion 352 may be provided over the outer peripheral portions of the upper member 310 and the lower member 320. Specifically, the crossover portion 352 is installed over the recessed portion 314 and the recessed portion 324 provided at the lower portion of the outer peripheral portion of the upper member 310 and the upper portion of the outer peripheral portion of the lower member 320, respectively, and the upper member 310. And can be joined to the lower member 320.

The protrusion 354 is provided on the crossover 352 along the direction of the tensile force applied to the joint 340. Thereby, the moment of inertia of area of the lower arm 30 in the cross section substantially orthogonal to the direction of the tensile force applied to the joint portion 340, which is represented by the cross section shown in FIG. 8, can be increased. Therefore, the rigidity in the direction of the tensile force applied to the joint portion 340 can be enhanced.

Further, the protrusion 354 of the reinforcing member 350 may protrude toward the inside of the lower arm 30. Specifically, the protrusion 354 projects from the central portion of the crossover portion 352 toward the closed space 330 side of the lower arm 30. In that case, the protrusion 354 is sandwiched between the upper member 310 and the lower member 320 at the joint portion 340. The protrusion 354 is joined to the upper member 310 and the lower member 320 in a state of being sandwiched between the lower end of the upper member 310 and the upper end of the lower member 320 at the joint 340. For example, the upper part of the protrusion 354 and the lower end of the upper member 310 and the lower part of the protrusion 354 and the upper end of the lower member 320 are joined by using an adhesive.

As described above, as shown in FIG. 4, when a force toward the rear side of the vehicle body is applied to the tip end portion of the lower arm 30, a tensile force is applied to the portion 340a on the front side of the vehicle body of the joint portion 340 to join. A compressive force is applied to the portion 340b on the rear side of the vehicle body of the portion 340. When a unidirectional fiber reinforced resin member in which reinforcing fibers are oriented along the direction of the tensile force applied to the joint 340 is used as the reinforcing member 350, the rigidity in the direction of the tensile force applied to the joint 340 is to be strengthened. Can be done. In such a case, the deformation of the lower arm 30 due to the pulling force applied to the portion 340a on the front side of the vehicle body of the joint portion 340 can be suppressed by the front reinforcing member 350a.

Here, it is generally known that the neutral axis in bending deformation of an object may not be located at the center of the object. Therefore, when the lower arm 30 is deformed and a compressive force is applied to the rear portion 340b of the joint portion 340, the protrusion 354b protruding toward the closed space 330 provided in the rear reinforcing member 350b. Tensile forces may be applied to at least part of it. In such a case, in the modified example, the deformation of the lower arm 30 can be suppressed more effectively by receiving a part of the pulling force generated on the lower arm 30 by the protrusion 354b.

<4. Summary>
As described above, according to the present embodiment, the reinforcing member 250 is provided over the upper member 210 and the lower member 220, and extends along the joint portion 240 of the upper member 210 and the lower member 220. Thereby, the adhesive area between the members that contributes to the joint strength between the upper member 210 and the lower member 220 can be increased. Therefore, the joint strength between the upper member 210 and the lower member 220 can be increased. Further, the reinforcing member 250 strengthens the rigidity in the direction of the tensile force applied to the joint portion 240 of the upper member 210 and the lower member 220 when the lower arm 20 is bent and deformed. As a result, when a relatively large load that causes bending deformation is input to the lower arm 20, the deformation of the lower arm 20 can be suppressed. Therefore, the strength of the lower arm 20 against bending deformation can be improved.

In the above, an example in which the reinforcing member 250 or the crossover portion 352 is provided over the outer peripheral portions of the upper member and the lower member has been described, but the positional relationship between the reinforcing member 250 or the crossover portion 352 and the upper member and the lower member is relevant. Not limited to the example. For example, the reinforcing member 250 or the crossover portion 352 may be provided over the inner peripheral portions of the upper member and the lower member.

Further, in the above description, the example in which the protrusion 354 projects toward the inside of the lower arm 30 has been described, but the protrusion 354 may protrude toward the outside of the lower arm 30. In such a case, the protrusion 354 projects from the crossover 352 to the side opposite to the closed space 330 of the lower arm 30, for example.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or applications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1 Suspension device 2 Engine room 3 Front wheel apron 5 Side frame 6 Strut tower 6a Strut support 7 Suspension 7a Strut upper mount 8 Suspension cross member 9 Arm support 9a, 9b Bracket 9c Bolt insertion hole 11 Front wheel 12 Bolt 13 Nut 20, 30, 90 Lower arm 21 First base 22 Second base 23 Tip 27 Bush 28 Bush 29 Bush 210, 310, 910 Upper member 212, 312, 912 Recess 214, 314 Recess 220, 320, 920 Lower member 222, 322, 922 Recesses 224, 324 Recesses 230, 330, 930 Closed spaces 240, 340, 940 Joints 250, 350 Reinforcing members 352 Crossing 354 Protrusions

Claims (6)

A lower arm mounted on a vehicle including an upper member made of fiber reinforced plastic and a lower member.
A reinforcing member provided over the upper member and the lower member and extending along a joint portion of the upper member and the lower member is provided.
The reinforcing member includes a front side reinforcing member located on the front side of the vehicle body and a rear side reinforcing member located on the rear side of the vehicle body.
The front side reinforcing member enhances the rigidity in the direction of the tensile force applied to the front side portion of the vehicle body of the joint portion when the lower arm is bent and deformed.
The rear side reinforcing member enhances the rigidity in the direction of the tensile force applied to the rear side portion of the vehicle body of the joint portion when the lower arm is bent and deformed .
Each of the upper member and the lower member is provided with a recess.
By facing the recesses of the upper member and the lower member, a closed space is formed on the inner side of the lower arm.
The reinforcing member is provided along the direction of the pulling force and has a protrusion protruding toward the closed space side.
Lower arm. The reinforcing member further has a crossover portion that is provided across the upper member and the lower member and extends along the joint.
The protrusion protrudes from the crossover toward the closed space side.
The lower arm according to claim 1. The lower arm according to claim 1 or 2 , wherein the reinforcing member is a unidirectional fiber reinforced resin member in which reinforcing fibers are oriented along the direction of the tensile force. The protrusions of the reinforcing member before Symbol junction, the sandwiched by the upper member and the lower member, the lower arm according to any one of claims 1-3. The lower arm according to any one of claims 1 to 4, wherein the reinforcing member is provided over the upper member and the outer peripheral portion of the lower member. It has a first base on the front side of the vehicle body and a second base on the rear side of the vehicle body supported by the vehicle body.
The front side reinforcing member is along the portion between the tip of the lower arm and the first base at the joint, and when the lower arm is bent and deformed, the tip of the lower arm at the joint and the front are said. Strengthen the rigidity in the direction of the tensile force applied to the portion between the first base and
The rear reinforcing member is along a portion between the tip of the lower arm and the second base at the joint, and the tip of the lower arm at the joint and the tip of the lower arm at the joint when the lower arm is bent and deformed. Strengthens the rigidity in the direction of the tensile force applied to the portion between the second base,
The lower arm according to any one of claims 1 to 5 .

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